Δημοφιλείς αναρτήσεις

! # Ola via Alexandros G.Sfakianakis on Inoreader

Κυριακή, 12 Μαΐου 2019

Pediatric Radiology

Magnetic resonance neurography of traumatic pediatric peripheral nerve injury: beyond birth-related brachial palsy

Abstract

Traumatic peripheral nerve injury occurs more frequently in the pediatric population than previously recognized. High-resolution magnetic resonance (MR) imaging in the form of MR neurography can serve as a powerful noninvasive tool for detecting and characterizing peripheral nerve injury in children. In this review article we briefly discuss optimal methods of MR neurography image acquisition, highlighting core MR sequences necessary to characterize peripheral nerve injury. In addition, we illustrate the MR neurography appearance of normal and abnormal peripheral nerves in children, with emphasis on commonly used Seddon and Sunderland classification schemes to characterize peripheral nerve injury severity. The primary and secondary features associated with peripheral nerve injury including skeletal muscle denervation are reviewed in addition to key distinctive features that can impact operative versus nonoperative management of children. We include a checklist approach to interpreting MR neurography for the assessment of peripheral nerve injury.



Correction to: European Society of Paediatric Radiology abdominal imaging task force: statement on imaging in very early onset inflammatory bowel disease

The above article was published online with incorrect author name. The right spelling should be Damjana Kljucevsek instead of Damjana Kjucevsek. The correct name is presented here.



Evaluating growth failure with diffusion tensor imaging in pediatric survivors of high-risk neuroblastoma treated with high-dose cis-retinoic acid

Abstract

Background

The survival of patients with high-risk neuroblastoma has increased with multimodal therapy, but most survivors demonstrate growth failure.

Objective

To assess physeal abnormalities in children with high-risk neuroblastoma in comparison to normal controls by using diffusion tensor imaging (DTI) of the distal femoral physis and adjacent metaphysis.

Materials and methods

We prospectively obtained physeal DTI at 3.0 T in 20 subjects (mean age: 12.4 years, 7 females) with high-risk neuroblastoma treated with high-dose cis-retinoic acid, and 20 age- and gender-matched controls. We compared fractional anisotropy (FA), normalized tract volume (cm3/cm2) and tract concentration (tracts/cm2) between the groups, in relation to height Z-score and response to growth hormone therapy. Tractography images were evaluated qualitatively.

Results

DTI parameters were significantly lower in high-risk neuroblastoma survivors compared to controls (P<0.01), particularly if the patients were exposed to both cis-retinoic acid and total body irradiation (P<0.05). For survivors and controls, DTI values were respectively [mean ± standard deviation]: tract concentration (tracts/cm2), 23.2±14.7 and 36.7±10.5; normalized tract volume (cm3/cm2), 0.44±0.27 and 0.70±0.21, and FA, 0.22±0.05 and 0.26±0.02. High-risk neuroblastoma survivors responding to growth hormone compared to non-responders had higher FA (0.25±0.04 and 0.18±0.03, respectively, P=0.02), and tract concentration (tracts/cm2) (31.4±13.7 and 14.8±7.9, respectively, P<0.05). FA, normalized tract volume and tract concentration were linearly related to height Z-score (R2>0.31; P<0.001). Qualitatively, tracts were nearly absent in all non-responders to growth hormone and abundant in all responders (P=0.02).

Conclusion

DTI shows physeal abnormalities that correlate with short stature in high-risk neuroblastoma survivors and demonstrates response to growth hormone treatment.



Functional and structural connectivity of the brain in very preterm babies: relationship with gestational age and body and brain growth

Abstract

Background

Structural and functional changes of the brain have been reported in premature babies.

Objective

To evaluate the relationship of functional and structural connectivity with gestational age, body growth and brain maturation in very preterm babies.

Materials and methods

We studied 18 very preterm babies (gestational age: mean ± standard deviation, 29.7±1.7 weeks). We examined functional connectivity by multivariate pattern analysis of resting-state functional MRI data. We assessed structural connectivity by analysis of diffusion tensor imaging data and probabilistic tractography.

Results

The average functional connectivity of the medial orbitofrontal cortex with the rest of the brain was positively associated with gestational age (P<0.001). Fractional anisotropy of the right inferior fronto-occipital fasciculus was positively associated with head circumference at term-equivalent age. Structural connectivity of the inferior fronto-occipital fasciculus with the medial orbitofrontal cortex was positively associated with head circumference at term-equivalent age. Body weight at term-equivalent age was the only independent predictor of average structural connectivity of the medial orbitofrontal cortex with the rest of the brain (P=0.020).

Conclusion

Structural and functional connectivity of the medial orbitofrontal cortex with the rest of the brain depend on body growth and degree of prematurity, respectively.



Pediatric optic nerve and optic nerve sheath diameter on magnetic resonance imaging

Abstract

Background

The normal values of optic nerve diameter and optic nerve sheath diameter might be beneficial in defining an abnormality such as optic nerve hypoplasia, or enlarged subarachnoid space, reflecting the state of increased intracranial pressure.

Objective

To study the normal optic nerve diameter and optic nerve sheath diameter on magnetic resonance imaging (MRI) in the early years of postnatal visual development from MRI of the brain.

Materials and methods

MRI of the brain in patients ages 4 years and younger were gathered. Forty-two studies with normal intracranial findings and a lack of history of increased intracranial pressure were retrospectively reviewed by two reviewers using axial T2-weighted images. Measurements were performed in transverse diameter perpendicular to the optic nerve at 3 mm behind the globe.

Results

The mean optic nerve diameter of the 77 optic nerves were 2.5 mm (95% confidence interval [CI] 2.4–2.6). The mean optic nerve sheath diameter values of the 79 optic nerve sheath complexes were 5.0 mm (95% CI 4.9–5.1). The mean±standard deviation optic nerve diameter and optic nerve sheath diameter stratified by each age groups were, respectively, 0 to <1 year: 2.3±0.40 and 4.81±0.37; 1 to <2 years: 2.6±0.2 and 5.0±0.4; 2 to <3 years: 2.4±0.3 and 4.9±0.6, and 3 to <4 years: 2.9±0.4 and 5.2±0.60 mm.

Conclusion

Seventy-four of the 77 measurements (96%) were of the measurements were above the threshold of 2 mm for optic nerve diameter. Seventy-seven of the 79 measurements (97%) were of the measurements were below the threshold of 6 mm for optic nerve sheath diameter.



Magnetic resonance imaging T1 relaxation times for the liver, pancreas and spleen in healthy children at 1.5 and 3 tesla

Abstract

Background

T1 relaxation time is a potential magnetic resonance imaging (MRI) biomarker for fibrosis and inflammation of the solid abdominal organs. However, normal T1 relaxation times of the solid abdominal organs have not been defined for children.

Objective

The purpose of this study was to measure T1 relaxation times of the liver, pancreas and spleen in healthy children.

Materials and methods

This was an institutional review board-approved study of a convenience sample of prospectively recruited, healthy children ages 7 to 17 years undergoing research abdominal MRI (1.5 or 3 T) as part of a larger research study between February 2018 and October 2018. For the current study, T1 mapping was performed with a Modified Look-Locker sequence covering the upper abdomen. A single reviewer placed freehand regions of interest on the T1 parametric maps in the liver, pancreas and spleen, inclusive of as much parenchyma as possible. Student's t-tests and linear regression were used to compare T1 values by age and gender.

Results

Thirty-two participants were included (16 female:16 male; mean age: 12.2±3.1 years; n=16 at 1.5 T). Median T1 relaxation times (ms) per organ were liver: 581±64 (1.5 T), 783±88 (3 T); pancreas: 576±55 (1.5 T), 730±30 (3 T), and spleen: 1,172±71 (1.5 T), 1,356±87 (3 T). T1 values were not statistically significantly different between males and females. At both 1.5 and 3 T field strengths, linear regression showed no significant association between age and T1 values for the liver, pancreas and spleen.

Conclusion

We report normal T1 relaxation times for the liver, pancreas and spleen at 1.5 and 3 T in a cohort of healthy children.



Correction to: The value of postmortem computed tomography in paediatric natural cause of death: a Dutch observational study

When first published, this article inadvertently listed the Dutch NODO group individually within the author list without specifying the names of the collaborators. The collaborators have been listed within the Acknowledgements section only. The corrected author list is presented in this Correction.



Correction to: A consensus response on the complete picture: reply to Lynøe and Eriksson

The original version on this paper contained an error. The COI statement is incorrectly presented.



Correction to: The spectrum of cloacal malformations: how to differentiate each entity prenatally with fetal MRI

The published version of this article unfortunately contained a mistake. Author name Mariana Z. Meyers was incorrect. The correct middle initial is given above.



Pediatric radiologists and burnout: identifying stressors and moving forward


Cell and Tissue Biology

Multinucleated Cells Resistant to Genotoxic Factors within Human Glioblastoma Cell Lines

Abstract

Glioblastoma tumors are characterized by a high phenotype diversity among patients and by a high cellular heterogeneity within each tumor instance. Here, we report the effects of photon irradiation of various dosage and regime onto cells of two reference (T98G and A172) and two novel (T2 and R1) human glioblastoma cell lines. In contrast to the A172 and R1 lines, where all cells were perished upon relatively low-dose irradiation, a population of resistant cells within the T98G and T2 lines survived even after a high-dose irradiation. These radio-resistant cells were large single- or multinucleated non-proliferating cells, that remained viable over one month after irradiation. The cells had markedly elevated expression levels of genes coding for factors promoting growth and angiogenesis, components of the extracellular matrix, and marker genes in-herent for mesenchymal phenotype. The expression profile of these genes in the radiation-induced growth-arrested cells T98G and Т2 was similar to that of the cell lines treated with another genotoxic factor, the fotemustine. Therefore, radio-resistant growth-arrested cells are characterized by a high activity of genes encoding proteins affecting both the tumor cells and their microenvironment.



Specific Features of the Ultrastructure and Biochemical Composition of Triticum spelta L . Leaf Mesophile Cells in the Initial Period of Stress Temperature Action

Abstract

Under controlled conditions, the effect of high (40°C, 2 h) and positive low (4°C, 2 h) temperatures on the ultrastructure of mesophyll cells of the leaf and the content of photosynthetic pigments, phenols, and flavonoids in 2-week-old Triticum spelta plants was studied. The ultrastructure of the mesophyll cells of the leaf of the control plants was typical: a developed thylakoid system was clearly seen that was immersed in a fine-grained stroma in the chloroplasts of regular lenticular shape. Short-term hyperthermia caused a partial destruction of thylakoid membranes. Wave-shaped packing of grana thylakoids, significant expansion of lumen intervals, disturbance of the structural bond between the grana thylacoids and stroma thylakoids was noted. With hyperthermia, the mitochondria noticeably "swelled," while the cristae membranes became less contrasting. The number of lipid droplets increased in the cytoplasm of cells. In the leaves, the content of chlorophylls and carotenoids decreased, however, the number of common phenols and flavonoids increased. Short-term hypothermia caused intense formation of plastoglobules, and an increase in the number and size of starch grains. Destruction of thylakoid membranes was not observed. Some of the mitochondria were rounded (40%), with their size being close to the control values, and some organelles were lenticular, "dumbbell," and "cup-shaped." Under hyper- and hypothermia, the T. spelta leaf mesophyll cells showed a tendency to increase the degree of chromatin condensation in the nucleus. Under hypothermia, the content and ratio of chlorophylls and carotenoids in leaves did not differ much from the control plants, and no significant quantitative changes in the total phenols and flavonoids were recorded.



Chromosomal Instability and Evolution of Transformed Phenotype in Cell Lines Selected from Senescent Rat Embryonic Fibroblasts with Rapamycin

Abstract

The karyotype and phenotype evolution in cell lines (Rapa) obtained by rapamycin selection from rat embryonic fibroblasts (REF) has been studied. Rapamycin, an inhibitor of mTORC1 kinase, prevents replicative aging of REF cells starting after seven to ten passages in vitro. The karyotype of the established cell lines undergoes an evolution upon their cultivation in vitro. On early passages, clonal chromosome rearrangements, more specifically trisomy of chromosome 7 and translocations t(2;7) or t(4;11), were observed. Chromosome rearrangements (CR) accumulated at late passages. Simultaneously, signs of the transformed phenotype appeared: capacity for clonal growth, a decrease in contact inhibition, and high proliferation rate in the monolayer at saturating density. The evolution of the transformed phenotype was accompanied by the loss of G1/S and/or G2/M checkpoint control. Rapa lines were characterized by accumulation of γH2AX and p53BP foci, which, however, did not colocalize. Thus indicates the accumulation of unrepaired double-strand DNA breaks (DSB). The Rapa lines are shown to express the pluripotency markers Nanog and Oct3/4. The causes of genetic and karyotype instability of Rapa lines during long-term cultivation have been discussed.



Entosis and Cell Cycle in Tumor Cell Culture

Abstract

Entosis is a type of cell cannibalism during which one tumor cell invades another. The fate of the inner cell can vary. It can leave the entotic vacuole, divide within it, or be subjected to lysosome-mediated degradation. The aim of our work was to determine whether MCF7 (p53+) human breast adenocarcinoma cells and A431 (p53-) human epidermoid carcinoma cells can pass through the cell cycle during entosis. The percentage of entotic cells was 1.01 ± 0.37% in MCF7 culture and 0.42 ± 0.27% in A431 culture. It was shown that inner cells, as well as outer cells, can synthesize DNA (BrdU incorporation) and enter mitosis. Morphometric analysis showed polyploidization of outer cells. This process is most pronounced in the A431 (p53–) cell line. In addition, polyploid cells may be the preferred targets of invasion in this culture. In the MCF-7 cell line, the number of G1-phase entotic cells was higher, probably due to p53-mediated cell cycle arrest or the preferred cell invasion in the G1-phase. Overall, in tumors with active p53 protein expression, the entosis contribution to polyploidy and genetic instability of tumor cells is less than in p53 tumor cells.



Intranuclear Actin Distribution at the Four- and Eight-Cell Stages of Mouse Embryo Development

Abstract

Intranuclear distribution of actin was studied in mouse embryos in the middle and end of the four-cell stage of development, as well as in the blastomeres of uncompacted eight-cell embryos. Actin was visualized with direct fluorescence, indirect immunofluorescence and confocal microscopy. It was found that nuclei at these stages of development contained monomeric, as well as polymeric actin, differing from conventional filamentous. The pattern of actin distribution in the nuclei at the middle-stage four-cell embryos and uncompacted eight-cell embryos was similar. Comparison of this pattern with nuclear actin distribution in the two-cell embryos that we examined previously showed that at the early stages of embryo cleavage the intranuclear actin localization was not stage-specific and was stably reproduced in the nuclei of the embryos during transition from earlier to later stage of embryogenesis. Filamentous actin that had not been found in the nuclei of middle-stage four-cell embryos was detected by fluorescent phalloidin in the nuclei of the embryos at the end of a four-cell stage of development, shortly before the beginning of the third cleavage division. The appearance of nuclear filamentous actin is possibly related to the preparation of embryos to the following cleavage division.



Mononuclear Cells of Peripheral Blood in vitro. A Model of Antipsychotic Therapy Personalization

Abstract

The implementation of a unified strategy for prescribing antipsychotics has proved to be an ineffective approach to the treatment of mentally ill patients. The study of the efficiency of pharmacological drugs on models mimicking the individual pathophysiology of the patient is one means of personalized (predictive) therapy. We evaluated the mRNA level for the genes of the neurotransmitters' receptors (ADR1BHRH1HTR2АDRD1DRD2DRD4, and DRD5). These are targets of antipsychotic drugs; therefore, they can be used as the probable biomarkers of the success of the treatment of mental illnesses of schizophrenic spectrum. We used peripheral blood mononuclear cells (PBMC) in vitro as the therapeutic model. The study included 108 patients with a proved diagnosis of schizophrenia spectrum disorders, receiving a haloperidol or olanzapine as a monotherapy. The patients were divided into two groups based on their response to the pharmacotherapy (effective or ineffective). The response was estimated with psychometric analysis performed on 28 ± 2 days of the treatment. In the group with ineffective therapy, the level of expression of the studied genes in PBMC in vitro had increased with the presence of the antipsychotic drug, while, in the group of patients with positive dynamics of mental status normalization, the analyzed level of expression remained virtually unchanged. The highest significant differences for patients with different responses on the pharmacological treatment were observed for the ADR1B and HRH1 genes in the case of olanzapine therapy (Р = 0.004 and 0.038, respectively) and for the HTR2A gene in the case of haloperidol therapy (Р = 0.039). At the same time, basic levels of gene expression in non-cultivated PBMC were not associated with the patient's response to therapy. Thus, the mRNA level for genes of neurotransmission in PBMC in vitro in the presence of antipsychotics can be proposed as a biomarker for predicting the pharmacotherapy outcome for mentally ill patients.



Comparative Morphometry of Epithelial- and Fibroblast-like Type Cells in Culture

Abstract

Two morphological types, epithelial- and fibroblast-like, can be visually observed in cultivated cells. The first includes rounded and inactive cells. The cells of the second type have an elongated shape and filopodia-like outgrowths. It is obvious that these characteristics are largely subjectively determined; this complicates studying the biology of the cells adaptable and adapted to growth in culture. We have proposed a quantitative characteristic (EF indices) for their formalization. They can be used to estimate the percentage of the contribution of, respectively, filopodia (EF1), elongation or polarization (EF2), and the cell roundness (EF3) to the cell shape using the example of six different cell lines, it was demonstrated that EF1 = 15.4 ± 2.6, EF2 = 2.9 ± 1.9, and EF3 = 81.7 ± 3.2% for epithelial-like cells and 39.9 ± 5.9, 4.5 ± 0.4, and 55.6 ± 5.6% for fibroblast-like cells. It was concluded that, if the cells of two lines have differences in at least one of the indices, they can be assigned to different cell types.



Additional Prognostic Markers of Human Colon Adenocarcinoma

Abstract

The expression of potential prognostic markers of human colon adenocarcinoma in tumor and adjacent normal tissue, as well as the relationship between their expression levels was studied. The expression of potential prognostic markers (IGFBP3, AhR, CYP1A1, CYP1B1, HIF-1α, OCT4A, OCT4B, OCT4B1) was assayed with quantitative RT-PCR (qPCR). A correlation between IGFBP3 and AhR expression was found. AhR signaling was analyzed in the primary culture of human colon adenocarcinoma BSK 8 with IGFBP3 gene knockout. It was found that the enhanced expression of AhR can be an additional diagnostic criterion for colon cancer. The correlation between the expression level of HIF-1α, IGFPB3, and OCT4 isoforms and clinic stage (TNM) was not estimated. Clones with IGFBP3 gene knockout had augmented doubling time and increased resistance to the cytostatic drug 5-ftoruracile after modulated activity of dioxin receptor with its agonist—indol-3-carbinol.



CD4+ T-Cell Cycling in HIV-Infected Patients with the Discordant Immunologic Response to the Antiretroviral Therapy

Abstract

Discordant immune response to antiretroviral therapy (ART) in HIV infection is characterized by insufficient reconstitution of peripheral CD4+ T lymphocyte numbers despite suppression of virus replication. The causes of inefficient regeneration of CD4+ T cells on ART remain elusive. The paper reports the study involving two groups of HIV-positive patients: patients with discordant response to ART (n = 20) and patients with standard response to therapy (n = 21). The numbers of cycling (Ki-67+), senescent (CD57+), and exhausted (PD-1+) CD4+ T lymphocytes of varying degree of maturity have been determined in peripheral blood and lymph nodes of HIV-positive individuals. CD4+ T cell division asymmetry index after in vitro stimulation has been analyzed. Histological study of the lymph nodes of HIV-infected patients was carried out. It has been demonstrated that in the individuals with discordant immune response to ART, intensive CD4+ T cell cycling does not result in the increase in their count neither in peripheral blood, nor in the secondary lymphoid organs. At the same time, in the patients with impaired immune system recovery, increased cell proliferation is followed by the accumulation of exhausted CD4+ T lymphocytes. Moreover, patients with discordant immune response to ART revealed an asymmetric division of in vitro stimulated CD4+ T cells. The observed defects may be the cause of inefficient immune system recovery in HIV-infected patients on ART.



Analysis of NAD and NAD-Dependent Protein Deacetylation in Mouse Tissues

Abstract

Nicotinamide adenine dinucleotide (NAD) plays a key role in the vital metabolic and regulatory processes in mammals. Disturbance of the NAD level regulation is associated with the development of such serious diseases as pellagra, neurodegenerative and cardiovascular disorders, diabetes, cancer and others. This paper presents an experimental approach that allows to determine the amount of NAD+ in mouse tissues using NMR spectroscopy, as well as the level of NAD+-dependent deacetylation of proteins in the cytosol and mitochondria.



Radiation and Environmental Biophysics

Correction to: Dose–responses for mortality from cerebrovascular and heart diseases in atomic bomb survivors: 1950–2003

The article Dose–responses for mortality from cerebrovascular and heart diseases in atomic bomb survivors: 1950–2003, written by Helmut Schöllnberger.



Obituary Prof. Dr. Dietrich Harder (11 February 1930–10 February 2019)


Improved identification of DNA double strand breaks: γ-H2AX-epitope visualization by confocal microscopy and 3D reconstructed images

Abstract

Currently, in the context of radiology, irradiation-induced and other genotoxic effects are determined by visualizing DSB-induced DNA repair through γ-H2AX immunofluorescence and direct counting of the foci by epifluorescence microscopy. This procedure, however, neglects the 3D nature of the nucleus. The aim of our study was to use confocal microscopy and 3D reconstructed images to improve documentation and analysis of γ-H2AX fluorescence signals after diagnostic examinations. Confluent, non-dividing MRC-5 lung fibroblasts were irradiated in vitro with a Cs-137 source and exposed to radiation doses up to 1000 mGy before fixation and staining with an antibody recognizing the phosphorylated histone variant γ-H2AX. The 3D distribution of γ-H2AX foci was visualized using confocal laser scanning microscopy. 3D reconstruction of the optical slices and γ-H2AX foci counting were performed using Imaris Image Analysis software. In parallel, γ-H2AX foci were counted visually by epifluorescence microscopy. In addition, whole blood was exposed ex vivo to the radiation doses from 200 to 1600 mGy. White blood cells (WBCs) were isolated and stained for γ-H2AX. In fibroblasts, epifluorescence microscopy alone visualized the entirety of fluorescence signals as integral, without correct demarcation of single foci, and at 1000 mGy yielded on average 11.1 foci by manual counting of 2D images in comparison to 36.1 foci with confocal microscopy and 3D reconstruction (p < 0.001). The procedure can also be applied for studies on WBCs. In contrast to epifluorescence microscopy, confocal microscopy and 3D reconstruction enables an improved identification of DSB-induced γ-H2AX foci, allowing for an unbiased, ameliorated quantification.



Influence of the external and internal radioactive contamination of the body and the clothes on the results of the thyroidal 131 I measurements conducted in Belarus after the Chernobyl accident—Part 2: Monte Carlo simulation of response of detectors near the thyroid

Abstract

This paper describes the calculation of the response of the most common types of radiation detectors that were used within the first few weeks after the Chernobyl accident to determine the activity of 131I in the thyroids of Belarusian subjects of an epidemiologic study of thyroid cancer. The radiation detectors, which were placed against the necks of the subjects, measured the exposure rates due to the emission of gamma rays resulting from the radioactive decay of 131I in their thyroids. Because of the external and internal radioactive contamination of the monitored subjects, gamma radiation from many radionuclides in various locations contributed to the exposure rates recorded by the detectors. To estimate accurately the contribution from gamma rays emitted from various internal and external parts of the body, the calibration factors of the radiation detectors, expressed in kBq per µR h− 1, were calculated, by means of Monte Carlo simulation, for external irradiation from unit activities of 17 radionuclides located on 19 parts of the body, as well as for internal irradiation from the same 17 radionuclides in the lungs, from caesium radionuclides distributed uniformly in the whole body, and from 131I in the thyroid. The calculations were performed for six body sizes, representative of the age range of the subjects. In a companion paper, the levels of external and internal contamination of the body were estimated for a variety of exposure conditions. The results presented in the two papers were combined to calculate the 131I activities in the thyroids of all 11,732 Belarusian study subjects of an epidemiologic study of thyroid cancer and, in turn, their thyroid doses.



A study of the protective actions for a hypothetical accident of the Bushehr nuclear power plant at different meteorological conditions

Abstract

In this work, protective actions have been studied assuming a hypothetical severe accident of the Bushehr nuclear power plant at different meteorological conditions. Simulations of the atmospheric dispersion of accidental airborne releases were performed using the RASCAL code. Total effective dose equivalent (TEDE) and thyroid dose received by members of the public living within a radius of 40 km around the reactor site were calculated for various atmospheric stability classes and weather conditions. According to the results of the dose assessment and by following the protective action guide of the Environmental Protection Agency (EPA), the critical zone and appropriate protective actions were determined depending on various metrological conditions. It was found that, for atmospheric stability class F and calm weather conditions, the maximum distance from the site of release for which TEDE is greater than the corresponding dose limit and for which sheltering or evacuation response actions are required, is 11 km. For the same weather conditions, the corresponding maximum distance for which iodine prophylaxis is required is 32 km. Based on the present simulations, it can be concluded that the metrological condition has a great influence on the radionuclide atmospheric dispersion and, consequently, on the critical zone where protective actions are required after the assumed accident condition.



Efficient parameter estimation in multiresponse models measuring radioactivity retention

Abstract

After incorporation of radioactive substances, workers are routinely checked by bioassays (isotopic activity excreted via urine, measurements of radionuclides retained in the whole body or in the lungs, etc.). From the results, the isotopic activity incorporated by the worker is inferred, as well as the values of other parameters related to the metabolism of the incorporated substance, using the 'response function'. This function depends on several factors and it is usually obtained by solving a system of linear differential equations, resulting from the compartmental model which describes the human body (or a part of it). The possibility of using different types of bioassays from the same worker improves estimation of some of the parameters that characterize the solution of the system of equations, specially the unknown incorporated activity to the system. The transfer coefficients are usually considered to be known, using the values that are published in the corresponding International Commission of Radiological Protection (ICRP) publication. In the present study some practical cases will be presented, and optimal design criteria are developed that allow taking the bio-samples at the most informative times. The methodology presented here requires solving the models of element distribution in the human organism as a function of time, for which the recently updated models recommended by the ICRP have been used. Initially thought for workers in facilities dealing with radioactive substances, the study results, procedures and conclusions can be applied to other clinical or laboratory settings, and to the design of action protocols in case of environmental public exposure.



Dose optimization of lithium to increase the uptake and retention of I-131 in rat thyroid

Abstract

The present study was undertaken to optimize the dose of lithium, with an aim to increase the retention of I-131 in the thyroid follicles while maintaining the euthyroid state. 24 female Wistar rats weighing 110 ± 20 g were segregated into four groups. Animals in group I were fed standard laboratory feed and water throughout the period of experimentation. Animals in group II, III and IV were additionally fed with lithium in the form of lithium carbonate orally, at a dose of 10 mg/kg body weight, 20 mg/kg body weight, 30 mg/kg body weight respectively. The dose of lithium was started 1 week prior to radioiodine administration and continued thereafter for another 8 days. After 7 days of lithium treatment, 0.48 MBq of carrier-free I-131 was injected intraperitoneally into each rat, of the four groups. I-131 thyroidal uptake and biokinetics, as well as serum TSH, T3, T4 levels were estimated in all the treatment groups. A significant increase in the thyroid and whole body counts was observed after 4 and 24 h of I-131 aministration in lithium treated rats, compared to control animals. An increase in thyroidal effective t1/2 and serum TSH levels, along with decrease in the levels of serum T3 and T4 was observed with a dose of 20 mg/kg or higher. In Conclusion, a Lithium dose of 10 mg/kg body weight in rats could increase the uptake of I-131 in the thyroid, without disturbing the control circulating levels of thyroid hormones.



Validation of a system of models for plutonium decorporation therapy

Abstract

A recently proposed system of models for plutonium decorporation (SPD) was developed using data from an individual occupationally exposed to plutonium via a wound [from United States Transuranium and Uranium Registries (USTUR) Case 0212]. The present study evaluated the SPD using chelation treatment data, urine measurements, and post-mortem plutonium activities in the skeleton and liver from USTUR Case 0269. This individual was occupationally exposed to moderately soluble plutonium via inhalation and extensively treated with chelating agents. The SPD was linked to the International Commission on Radiological Protection (ICRP) Publication 66 Human Respiratory Tract Model (HRTM) and the ICRP Publication 30 Gastrointestinal Tract model to evaluate the goodness-of-fit to the urinary excretion data and the predictions of post-mortem plutonium retention in the skeleton and liver. The goodness-of-fit was also evaluated when the SPD was linked to the ICRP Publication 130 HRTM and the ICRP Publication 100 Human Alimentary Tract Model. The present study showed that the proposed SPD was useful for fitting the entire, chelation-affected and non-affected, urine bioassay data, and for predicting the post-mortem plutonium retention in the skeleton and liver at time of death, 38.5 years after the accident. The results of this work are consistent with the conclusion that Ca-EDTA is less effective than Ca-DTPA for enhancing urinary excretion of plutonium.



Monte Carlo-based determination of radiation leakage dose around a dedicated IOERT accelerator

Abstract

Evaluating the stray radiation around medical electron accelerators is a mandatory issue. Surveying the radiation leakage dose is important for patients, technicians, and health physicists, due to radiation protection aspects. Consequently, radiation leakage dose around the head of a mobile-dedicated intraoperative radiotherapy accelerator (LIAC), at different electron energies and field sizes have been evaluated in this study. More specifically, the MCNPX Monte Carlo code was used to model the LIAC head, connected applicator, and employed water phantom. Radiation leakage dose around the LIAC head was calculated for different energy and field sizes through tuning the Monte Carlo results to the practically measured doses. These measurements were performed using an Advance Markus ionization chamber inside an automated MP3-XS water phantom. The good agreement between the calculated dose distributions within the water tank and corresponding dose measurements show that the simulation model of the LIAC head is appropriate for radiation leakage assessment. The obtained radiation leakage dose distribution highly depends on the electron energy and applicator diameter. With increasing the electron energy, the leakage dose decreased, while increasing the field size increased the leakage dose. It is concluded that the rate of stray radiation and leakage dose around the LIAC head in both vertical and horizontal planes were acceptable according to the recommended radiation protection criteria. To meet the recommended dose limit (100 µSv/week for controlled areas), the maximum number of patients should be kept to four patients per week inside a standard and unshielded operating room.



Thyroid doses due to Iodine-131 inhalation among Chernobyl cleanup workers

Abstract

Several hundred thousand individuals, called 'cleanup workers' or 'liquidators', who took part in decontamination and recovery activities between 1986 and 1990 within the 30-km zone around the Chernobyl nuclear power plant in Ukraine, were mainly exposed to external irradiation. However, those who were involved in cleanup activities during the 10-day period of atmospheric releases also received doses to the thyroid gland due to internal irradiation resulting essentially from inhalation of 131I. The paper presents the methodology and results of the calculation of individual thyroid doses for cleanup workers. The model that was used considers several factors, including the ground-level outdoor air concentrations of 131I at the locations of residence and work of the cleanup workers, the reduction of 131I activity in inhaled air associated with indoor occupancy, the time spent indoors, the breathing rate, which depends on the type of physical activity, and the possible intake of potassium iodine (KI) for iodine prophylaxis. Thyroid doses were calculated for a group of 594 cleanup workers with individual measurements of exposure rate against the neck, called 'direct thyroid measurements', that were performed from 30 April to 5 May 1986. The measured values of exposure rate were corrected to subtract the contribution of short-lived radioiodine isotopes in the thyroid to the detector response. The average thyroid dose due to 131I inhalation by the cleanup workers was estimated to be 180 mGy, while the median was 110 mGy. Most of the cleanup workers (73%) received thyroid doses ranging from 50 to 500 mGy. The highest individual dose from 131I inhalation among the cleanup workers with direct thyroid measurements was 4.5 Gy. To validate the model, the 131I activities in the thyroids that were calculated using the model were compared with those derived from the direct thyroid measurements. The mean of the ratios of measured-to-calculated activities of 131I in the thyroid was found to be 1.6 while the median of those ratios was 0.8. For 60 cleanup workers with direct thyroid measurements, a detailed description of hour-by-hour whereabouts and work history was available. For these cleanup workers the mean of the ratios of measured-to-calculated activities was found to be 1.2 and the median of those ratios was 1.0. These encouraging results suggest that the thyroid dose due to 131I inhalation could be estimated for Chernobyl cleanup workers with a reasonable degree of reliability even in the absence of direct thyroid measurements. However, this conclusion assumes that detailed information on whereabouts and work history could be obtained for those cleanup workers who were not measured.



Biology

Longitudinal Stolon Pulsations in the Colonial Hydroid Dynamena pumila (Linnaeus, 1758)

Abstract

It is established via time-lapse video microscopy that the zone of longitudinal extension of the stolon coenosarc in the colonial hydroid Dynamena pumila can extend over two interstitial sites (modules). The stretching occurs in the form of oscillations with a period corresponding to the growth pulsations of the stolon tip. Consequently, the growth zone is not restricted to one stolon module, and the main condition for longitudinal growth of the coenosarc appears to be the stretching created by the advancing growth tip, not only by the increasing number of cells in the growth zone, as the main cause of coenosarc elongation.



Impact of Spatial Heterogeneity on Drosophila melanogaster Adaptation to Unfavourable Food Media: The Results of an Experimental Evolution Study

Abstract

The spatiotemporal variability of environmental conditions is assumed to have a strong impact on the course of microevolution processes, including the efficiency of adaptation to unfavourable conditions and the probability of ecological specialization or, conversely, generalization (the acquisition of multipurpose adaptations). The experimentаl research on these effects is still at the initial stage, and the temporal, rather than spatial, heterogeneity of the environment is analyzed in most studies. We performed an evolution experiment that involved the adaptation of Drosophila melanogaster lines to two unfavourable media: a high-salt (S) medium and a starch-based (St) medium of low nutritional value. Some of the experimental lines had access to one of the two unfavourable media only (homogeneous environment), whereas the others had access to both media and could choose between them (heterogeneous environment). The control lines were reared on a normal laboratory medium (N) that provided favourable conditions for the species. The degree of adaptation of lines obtained on the S, St, and N media was assessed after one and a half years of adaptation. The reproduction efficiency (the amount of adult progeny derived from a pair of parents within a specified time interval), adult lifespan, oviposition rate, and ageing-related changes in the former were assessed. Flies reared in a heterogeneous environment were superior to those reared in a homogeneous one with regard to most adaptation parameters on all three media. The results agree with the hypothesis concerning the promotion of generalization and more efficient adaptation to unfavourable conditions upon spatial heterogeneity of the environment. The obtained data do not support the hypothesis of antagonistic pleiotropy, which leads to "evolutionary trade-offs" and a lower competitiveness of generalists than that of specialists under stable conditions.



Growth, Coenosarc Pulsations, and Hydroplasm Movement in the Colonial Hydroid Dynamena pumila (L., 1758) Placed in Flow-Through and Nonflow Cuvettes

Abstract

The coenosarc pulsations of the stolon and hydroplasmic flows (HFs) in the colonial hydroid Dynamena pumila (L., 1758) have been recorded in flow-through and nonflow, shallow cuvettes via time-lapse video microscopy. The water in the flow-through cuvette was refreshed during every 24 s. Each episode was video recorded for 2 h. Eleven indicators were used to compare hydroid reactions to maintenance in flowing and nonflowing water: the period and amplitude of pulsations of the stolon growing tip; the hourly stolon growth; the period and amplitude of transverse coenosarc pulsations; the period of unidirectional HF rate pulsations; the maximum velocity of HFs to and from the stolon tip; the distance of particle transfer per act of unidirectional HF; the volume of displaced hydroplasm per HF; and the percentage of the rest ratio in coenosarc pulsations and hydroplasm movement. On the whole, no significant changes in the coenosarc pulsations or in the growth and displacement of the hydroplasm were detected when they were compared sequentially in the same colonies in nonflowing and flowing water. At the same time, there were no changes in the growth, the frequency and amplitude of the transverse pulsations of the coenosarc, or the activity and extent of the hydroplasm currents. However, it was found that the period of growth pulsations increases by 20% in the regime with water exchange in comparison with the previous regime without flowing water. The period of HFs in the stolon increases by 42%, and the maximum current velocity decreases by 20% in flowing water. As a result, the calculated volume of moved hydroplasm in the stolon for one HF decreased by 30% in flow conditions.



Parasitic Manipulations of the Host Phenotype: Effects in Internal and External Environments

Abstract

Parasites can influence their hosts in various ways. When a parasite changes the phenotype of its host to increase its own fitness, it is called parasitic manipulation of host phenotype. Perhaps, not all parasites are manipulators, but manipulations are undoubtedly a widespread natural phenomenon and well-established scientific concept. Parasites can manipulate the host phenotype to ensure their additional safety within the host body, create optimal conditions for their growth and development, and promote transmission from one host to another. Parasitic manipulative strategies are highly diverse and tightly connected with the parasite's life cycle. The review gives insight into the most common types of manipulative strategies and discusses (i) the evolutionary advantages of these strategies, (ii) why some strategies are more common than others, and (iii) how manipulative strategies change in the course of parasite growth and development. Recently, it has become clear that parasitic manipulations can be an important factor influencing the relationships in both the parasitic infracommunity within the host and the ecosystem in general. The last two sections of the review describe the conflicts and cooperation within the parasitic infrapopulation and the role of parasitic manipulations in ecosystems. The review concludes with a short, imaginary journey into the future that discusses how climate change may influence the role of parasites and their manipulations in the ever-changing environment.



Trends of Intraspecific Differentiation in the Beaked Redfish Sebastes mentella (Scorpaenidae) from the Atlantic Ocean and Adjacent Waters

Abstract

Based on studies of the population structure of the beaked redfish Sebastes mentella in the Atlantic and Arctic oceans, a conclusion has been made about the existence of another, epigenetic, trend of its intraspecific differentiation, in addition to the population trend. Analysis of the vast array of our data and those available in literature, which were obtained by the methodological approaches accepted in population biology, made it possible to distinguish three isolated populations of beaked redfish: the North Atlantic, the Norwegian Barents Sea, and the Flemish Cap. The first two are subdivided into demersal and pelagic epigenetic groups that differ morphophysiologically and ecologically. One of the main factors of the epigenetic differentiation of beaked redfish is ontogenetic—individuals reach sexual maturity at different times. Based on the dynamics of the physiological condition of gonads, two groups of fish are identified: early maturing individuals that mainly inhabit the ocean pelagic zone and late-maturing fish that predominantly live in the near-bottom layer along the continental slope. In the first group, the mass maturation of redfish (50% of individuals) occurs at an FL of 29–33 cm and the age of 9–12 years; in the second group, it occurs at an FL of 35–43 cm and the age of 14–19 years. Another factor of epigenetic differentiation is biotopic; it is manifested as the association of discrete groups with different biotopes. Late-maturing redfish stay in the near-bottom layer of the continental and island slopes throughout the year, while early maturing individuals tend to live in the pelagic zone of open ocean areas. The biotopic epigenetic differentiation is closely related to the onset of return migrations from the nursery grounds of juveniles upon their reaching maturity. Juvenile beaked redfish stay in the nursery ground, which is located in the shelf and shallow coastal waters, up to the age 6–10 years. Early maturing individuals are the first to leave the juvenile grounds and move to the ocean pelagic waters. Late-maturing fish, as they grow during prolonged (up to 5–7 years) migration, are recruited to demersal aggregations in deep-sea areas on continental slopes. The complication of the species' ecological structure due to the differentiation of epigenetic groups by biotopes has led to trophic specialization and weakening of the competitive interactions between them. Their habitation in different biotopes and the physiological polymorphism of redfish have not affected the unity of species populations. In the breeding season, there is no spatiotemporal isolation between the epigenetic groups, and the demersal and pelagic aggregations are replenished by common sources.



Modeling of the Damage Sustained by Forest Coenoses and Their Destruction under the Impact of Point Contamination Sources

Abstract

This paper addresses novel approaches to the description of ecosystem changes under the impact of contaminants, depending on their local concentration and impact duration. It is shown that, with quite simple assumptions about the biotic effects of a contaminant, this process can be considered an environmental analog of a second-order phase transition. Data on forest ecosystems in the vicinity of major point sources of contamination (copper smelting plants) were used for the analysis and verification of the proposed model.



Analyzing the Fine-Scale Dynamics of Two Dominant Species in a Polytrichum–Myrtillus Pine Forest. II. An Inhomogeneous Markov Chain and Averaged Indices

Abstract

Data from six repeated observations in a Polytrichum-type Scots pine forest are used to construct a nonautonomous Markov model of fine-scale dynamics of the two dominant species, bilberry (Vaccinium myrtillus) and lingonberry (V. vitis-idaea), at the late stages of postfire succession. The model consists of five transition matrices dependent on the observation year, and transition to the average matrix results in a homogeneous model. The design of the field experiment featured a large sample size on permanent transects (2000 quadrats × 6 observations), a 5-year reexamination interval, and the use of species rooting frequency on 20 × 20 cm quadrats over 25 years. The discrete Markov chain used to model the observed process of species alternation on the quadrats consists of four states: an absence of both species from the quadrat, the presence of one species of the two, and the joint presence of both species. The model time step coincides with the interval between the observations. The data allow for a unique calibration of the transition matrix for each pair of sequential observations, and the formulas of finite Markov chain theory yield the vectors of steady-state square distributions for each of the five temporal transitions. Fluctuations in the species rooting frequency among the observations are shown to exert substantial effects on the values of certain elements in the transition matrices and the components of the corresponding steady-state vectors (for particular pairs of observations), but there are no major changes in the conclusions concerning the dominating components (dominating states of the quadrats), regardless of the fluctuations. The geometric mean of five transition matrices recapitulates the spatial and temporal characteristics of the process over the entire observation period. We show that the stable terminal outcome of species dynamics is expected to involve the following distribution of quadrats among the states: 37% of the quadrats with V. myrtillus alone, 11% with V. vitis-idaea alone, 38% quadrats with both species present, and 14% "empty" quadrats. It is shown for the first time that the share of quadrats with V. vitis-idaea alone decreases considerably in the course of succession, whereas the share of quadrats with both species growing together increases. The averaged characteristics of the cyclicity and stage duration of the fine-scale dynamics make it possible to estimate the total duration of the secondary postfire succession (to reach a nearly terminal state) at 46–50 years. The quadrats with V. vitis-idaea alone have the shortest average lifetime among the described states (9 years), and those with both V. myrtillus and V. vitis-idaea have the longest average lifetime (18 years), which is partly explained by the different lifetimes of the species' shoots.



The Relation between the Species Diversity Index and Characteristics of Organism Communities in Waterbodies

Abstract

Based on literature data and our own, changes in the Shannon diversity index for the communities of organisms under changing environmental factors are considered. The eutrophication and pollution of waterbodies are shown to reduce the diversity of the communities; they become simpler, and the ratio of steno- to eurybiotic species decreases.



Estuarine Ecosystems and Their Place in Natural River Mouth Complexes of the Arctic: A Case Study of the Yenisei Mouth Area

Abstract

The estuarine ecosystem is characterized by the mixing of seawater and freshwater with a resulting salinity of 0.5 to 22–26‰, which is preserved for no less than 2–3 weeks, and by the presence of specific brackish water species. The distinguishing features of Arctic estuarine ecosystems are a sharp thermohaline stratification of the waters and, as a consequence, a difference in the boundaries of the brackish water biota distribution near the bottom and in the pelagic zone. Note that only the bottom estuarine biocenoses are characteristic of the river mouth area. The most important factor in the Arctic estuarine ecosystems is the longitudinal migrations of the halocline, especially seasonal ones. The coincidence of the borders of distribution of the true brackish water species with the borders of hydrological and morphological regions of the Yenisei River estuary defined according to long-term observations is noteworthy. Given the relative similarity of the Arctic estuarine ecosystems in their physical, chemical, and biotic components associated with the latitudinal uniformity of the mouths, we assume the presence of this correlation in other estuarine areas as well. In this case, a single survey of the benthos may give the same result as multiyear series of hydrological observations in the regionalization of an estuarine ecosystem.



In vitro Callus as a Model System for the Study of Plant Stress-Resistance to Abiotic Factors (on the Example of Cereals)

Abstract

The data on various aspects of the use of cereals callus cultures in vitro as model systems for the study of the plant stress-resistance to abiotic factors are presented. The focus is on studies of in vitro calli for the assessment of plant stress-resistance to drought stress. The advantages and limitations of callus cultures in vitro are considered as experimental methods to obtain stress-resistant regenerants. The issue of studying anti-stress effects in callus cultures in vitro is analyzed. The prospects of studying the mechanisms of the action of abiotic stressors and their resistance in plants at the cellular and tissue levels in the model conditions of in vitro callus culture are shown. It is emphasized that the basis for the use of calli as model systems is both the important role of the cell in all of the morphogenetic events of the plant organism in vivo and in vitro and the similarity of responses of plants in vivo, calli in vitro, and calli regenerants in vitro and ex vitro.



Fundamental and applied aspects of microbiology

Whole genome sequencing of a ST2594 MRSA strain causing non-mucosal preoperative colonization and low-grade postoperative infection

Abstract

We present a post-operative infection caused by a methicillin-resistant Staphylococcus aureus strain, previously isolated in the preoperative screening, in a patient submitted to femoral osteosynthesis, successfully treated with oral ciprofloxacin. The isolate exhibited in vitro resistance to ciprofloxacin, Staphylococcal Cassette Chromosome mec type IV, it was negative for the lukS-PV Panton–Valentine leucocidin gene and belonged to ST2594 in multilocus sequence typing analysis. Whole genome sequencing revealed a genome size of 2,818,289 base pairs. The annotated genomes of ST2594 and N315 strains were compared, looking for genes related to virulence and resistance. The lack of the tstsecsel genes, associated with a mutation in the clfA gene, may partially explain the low morbity in this case.



Renaming of ' Candidatus Methylocucumis oryzae' as Methylocucumis oryzae gen. nov., sp. nov., a novel Type I methanotroph isolated from India

Abstract

Candidatus Methylocucumis (Mcu.) oryzae, strain Sn10-6, a Gram-negative, pale pink pigmented, motile, large Type I methanotroph (3–6 µm × 1.5–2 µm) was recently isolated from an Indian rice field. Due to the difficulties in preservation of the strain it could not be deposited and preserved in two recognised culture collections with public access located in two different countries. Hence, Sn10-6 was described as a member of a Candidatusgenus and species, 'Ca. Mcu. oryzae'. Subsequent to the publication, the strain has been preserved in the Japan Collection of Microorganisms, Japan (JCM 32869T) in addition to its earlier preservation in the Korean collection for type cultures, KCTC, Korea and in National Centre for Microbial Resources, India. Addition of DMSO as a cryopreserving agent proved to be useful in the preservation of the strain. The deposition of the strain in two recognised culture collections in two different countries and additionally in the home country repository makes the strain eligible to be proposed as the type strain of the type species of a new genus and species with the name Methylocucumis oryzae strain Sn10-6T. In this paper we formally propose the name Mcu. oryzae, with Sn10-6T as the type strain, for the earlier described Ca. Mcu. oryzae. Other characteristics including the digital protologue of the culture (CA00040) remain the same as described earlier for Ca. Mcu. oryzae (Pandit et al. in Antonie Van Leeuwenhoek 111:2473–2484, 2018). Mcu. oryzae Sn10-6T (= MCC 3492 = KCTC 15683 = JCM 32869) represents a new genus and species within the family Methylococcaceae of the class Gammaproteobacteria.



Paracoccus indicus sp. nov., isolated from surface seawater in the Indian Ocean

Abstract

Strain IO390502T, isolated from surface seawater in the Indian Ocean, was characterised using a polyphasic taxonomy approach. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain IO390502T belongs to the genus Paracoccus and is closely related to Paracoccus seriniphilus DSM 14827T (97.6%), followed by P. zeaxanthinifaciens JCM 21774T (97.5%), P. homiensis DSM 17862T (97.3%), P. marcusiiDSM 11574T (97.2%), P. haeundaensis BC 74171T (97.0%) and P. carotinifaciens E-396T (97.0%). Cells are Gram-negative, aerobic, poly-β-hydroxybutyrate-accumulating, motile, rod-shaped, and forms creamy-white colonies. Optimal growth occurred at 25–30 °C, pH 5–8, and in the presence of 3–8% NaCl. The genome of strain IO390502T has a G+C content of 64.9 mol% and a 3.5 Mb chromosome. The in silico DNA–DNA hybridisation and average nucleotide identity values between strain IO390502T and the three closely related taxa, P. seriniphilus DSM 14827TP. zeaxanthinifaciens JCM 21774T and P. homiensis DSM 17862T, are 19.6%, 21.9% and 20.6%, and 76.0%, 79.9% and 77.8%, respectively. Phosphatidylglycerol is the major lipid present, ubiquinone-10 (Q-10) is the sole isoprenoid quinone, and the major cellular fatty acid is C18:1ω7c. Based on data from phenotypic tests and genotypic differences between strain IO390502T and its close phylogenetic relatives, strain IO390502T represents a new species belonging to the genus Paracoccus, for which the name Paracoccus indicus sp. nov. is proposed. The type strain is IO390502T (= JCM 32637T = CCTCC AB 2018071T).



Description of Wenzhouxiangella salilacus sp. nov., a moderate halophilic bacterium isolated from a salt lake in Xinjiang Province, China

Abstract

A Gram-stain negative, non-motile, strictly aerobic and rod-shaped bacterium, designated as 15181T, was isolated from a salt lake in Xinjiang Province, China. Strain 15181T was able to grow at 10–40 °C (optimum 37 °C), pH 6.0–8.5 (optimum 7.0) and with 1–14% NaCl (optimum 4%, w/v). According to phylogenetic analysis based on 16S rRNA gene sequences, strain 15181T was assigned to the genus Wenzhouxiangella with high 16S rRNA gene sequence similarity of 97.4% to Wenzhouxiangella sediminis XDB06T, followed by Wenzhouxiangella marina KCTC 42284T (95.9%). Strain 15181T exhibited ANI values of 80.0% and 72.0% to W. sediminisXDB06T and W. marina KCTC 42284T, respectively. The in silico DDH analysis revealed that strain 15181T shared 19.1% and 18.7% DNA relatedness with W. sediminis XDB06T and W. marina KCTC 42284T, respectively. Chemotaxonomic analysis showed that the sole respiratory quinone was ubiquinone-8, the major fatty acids included iso-C15:0, iso-C16:0 and summed feature 9 (C16:0 10-methyl and/or iso-C17:1ω9c). The major polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified glycolipids, two unidentified phospholipids, two unidentified aminophospholipids and an unidentified lipid. On the basis of phenotypic, genotypic and chemotaxonomic characteristics presented in this study, strain 15181T is concluded to represent a novel species in the genus Wenzhouxiangella, for which the name Wenzhouxiangella salilacussp. nov. is proposed. The type strain is 15181T (=KCTC 62172T=MCCC 1K03442T).



Description and genomic characterization of Massiliimalia massiliensis gen. nov., sp. nov., and Massiliimalia timonensis gen. nov., sp. nov., two new members of the family Ruminococcaceae isolated from the human gut

Abstract

Using the culturomics approach, we isolated two strains, Marseille-P2963 and Marseille-P3753, from the intestinal microbiota of a 19-year-old healthy Saudi Arabian Bedouin male and from a 32-year-old healthy Senegalese male faecal transplant donor. Here, we studied their phenotypic, phylogenetic and genomic characteristics. Both strains were phylogenetically related, but different from Ruminococcus species. Bacterial cells were anaerobic, rod-shaped, non-spore-forming and not motile, with neither catalase nor oxidase activities. Their growth temperatures ranged from 28 to 45 °C, with an optimal growth at 37 °C. The genomes are 2,842,720 bp- and 2,707,061 bp-long respectively. The G + C contents are 47.18% and 46.90%, respectively. Based on these characteristics, we propose the creation of a new genus within the family Ruminococcaceaenamed Massiliimalia gen. nov., that contains the new species Massiliimalia massiliensis gen. nov., sp. nov., and Massiliimalia timonensis gen. nov., sp. nov. Strains Marseille-P2963T (= CSUR P2963 = DSM 106837) and Marseille-P3753T (= CSUR P3753 = CCUG 71632) are their type strains, respectively.



Ethanol stress responses of Kluyveromyces marxianus CCT 7735 revealed by proteomic and metabolomic analyses

Abstract

Kluyveromyces marxianus CCT 7735 offers advantages to ethanol production over Saccharomyces cerevisiae, including thermotolerance and the ability to convert lactose to ethanol. However, its growth is impaired at high ethanol concentrations. Herein we report on the protein and intracellular metabolite profiles of K. marxianus at 1 and 4 h under ethanol exposure. The concentration of some amino acids, trehalose and ergosterol were also measured. We observed that proteins and metabolites from carbon pathways and translation were less abundant, mainly at 4 h of ethanol stress. Nevertheless, the concentration of some amino acids and trehalose increased at 8 and 12 h under ethanol stress, indicating an adaptive response. Moreover, our results show that the abundance of proteins and metabolites related to the oxidative stresses responses increased. The results obtained in this study provide insights into understanding the physiological changes in K. marxianus under ethanol stress, indicating possible targets for ethanol tolerant strains construction.



Rhodobacter thermarum sp. nov., a novel phototrophic bacterium isolated from sediment of a hot spring

Abstract

An ovoid to rod-shaped, phototrophic, purple non-sulfur bacterium was isolated from a sediment sample of a hot spring in Tibet, China. Cells of strain YIM 73036T were Gram-stain negative, non-motile and multiplied by binary fission. Strain YIM 73036T grew optimally at pH 7.0–7.5 at 37–45 °C. Growth occurred in 0.5–3.5% (w/v) NaCl. Vitamins were not required for growth. The presence of photosynthesis genes pufL and pufM were shown and photosynthesis pigments were formed. Bacteriochlorophyll α, the bacteriopheophytin and carotenoids were present as photosynthetic pigments. Internal cytoplasmic membranes were of the lamellar type. The organism YIM 73036T was able to grow chemo-organoheterophically, chemo-lithoautotrophically and photo-organoheterotrophically but photo-lithoautotrophic and fermentative growth were not demonstrated. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain YIM 73036T is closely related to Rhodobacter blasticus ATCC 33485T (96.65% sequence similarity) and clustered with species of the genus Rhodobacter of the family Rhodobacteraceae. Whole-genome sequence analyses based on the average nucleotide BLAST identity (ANI < 82%) indicated that this isolate belongs to a novel species. The genomic DNA G+C content of organism YIM 73036T was determined to be 66.0 mol%. Strain YIM 73036T contained Q-10 as the predominant ubiquinone and C18:1ω7c, C18:1ω7c 11-methyl and C18:0 as the major fatty acids. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and unidentified phospholipid. Differential phenotypic and chemotaxonomic properties, together with the phylogenetic distinctiveness, demonstrated that strain YIM 73036T is distinguishable from other species of the genus Rhodobacter. On the basis of the data presented, strain YIM 73036T is considered to represent a novel species of the genus Rhodobacter, for which the name Rhodobacter thermarum sp. nov. [type strain YIM 73036T (= KCTC 52712T = CCTCC AB 2016298T)] is proposed.



Dysgonomonas massiliensis sp. nov., a new species isolated from the human gut and its taxonogenomic description

Abstract

Culturomics has allowed the isolation of a significant number of new bacterial species from the human gut microbiota and proved to be a valuable complement to culture-independent techniques. Using this culture-based approach, a new bacterial species has been isolated from a stool sample of a 39-year-old healthy Pygmy male and described using the taxonogenomic strategy. Cells of strain Marseille-P4356T are Gram-stain negative cocci. The strain grows optimally at 37 °C and is catalase positive but oxidase negative. Its 16S rRNA gene sequence exhibited 92.96% sequence similarity with Dysgonomonas gadei strain JCM 16698T (NR_113134.1), currently its phylogenetically closest species that has been validly named. The genome of strain Marseille-P4356T is 3,472,011 bp long with 37.3 mol% G+C content. Phenotypic, biochemical, proteomic, genomic and phylogenetic analyses, clearly demonstrate that strain Marseille-P4356T (= CCUG 71356T = CSUR P4356T) represents a new species within the genus Dysgonomonas, for which we propose the name Dysgonomonas massiliensis sp. nov.



Salipaludibacillus keqinensis sp. nov., a moderately halophilic bacterium isolated from a saline–alkaline lake

Abstract

A novel Gram-stain positive, short rod, forming sub-terminal endospores of ellipsoidal shape, halophilic, alkaliphilic and aerobic bacterium, designated strain KQ-12T, was isolated from a saline–alkaline lake in China, and characterised by a polyphasic taxonomic approach. The isolate grew at 4–40 °C (optimum, 25 °C), at pH 8.0–10.0 (pH 9.0) and in the presence of 0–16% (w/v) NaCl (8%). 16S rRNA gene sequence similarity of KQ-12T to species in the genera Salipaludibacillus ranged from 96.6 to 98.1%. Phylogenetic trees indicated that the strain should be assigned to the genus Salipaludibacillus. The polar lipids of KQ-12T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and an unidentified phospholipid and its major cellular fatty acids were anteiso-C15:0, anteiso-C17:0, iso-C15:0, and C16:0. The isoprenoid quinone was MK-7. These key chemotaxonomic properties also confirmed the affiliation of the strain to the genus Salipaludibacillus. However, some physiological, biochemical properties, low average nucleotide identity and low digital DNA–DNA hybridization relatedness values enabled the strain to be differentiated from closely related species of the genus Salipaludibacillus. Thus, KQ-12T can be classified as a novel species in the genus Salipaludibacillus, for which the name Salipaludibacillus keqinensis sp. nov. is proposed. The type strain is KQ-12T ( =  ACCC 60430T   =  KCTC 33935T).



Nocardioides speluncae sp. nov., a novel actinobacterium isolated from a karstic subterranean environment sample

Abstract

A novel actinobacterial strain, designated YIM ART13T, was isolated from a soil sample collected from a karst cave in Xingyi county, Guizhou province, South western China. The taxonomic position of the strain was investigated using a polyphasic approach. Cells of the strain were found to aerobic and Gram-stain positive. On the basis of 16S rRNA gene sequence analysis, strain YIM ART13T was found to be closely related to Nocardioides pakistanensis NCCP 1340T (96.1% sequence similarity) and is therefore considered to represent a member of the genus Nocardioides. In addition, ll-diaminopimelic acid was identified as the diagnostic diamino acid in the cell wall peptidoglycan. The whole cell sugars were found to be mannose, galactose, glucose and ribose. The major isoprenoid quinone was identified as MK-8(H4), while the major fatty acids (> 10%) were identified as iso-C16:0, C18:1ω9c and C18:0 10-methyl. The polar lipids were found to contain diphosphatidylglycerol, phosphatidylglycerol phosphatidylinositol and phosphatidylinositol mannoside, an unidentified phospholipid. The genomic DNA G+C content of strain YIM ART13T was determined from the draft genome sequence to be 70.1 mol%. On the basis of phenotypic, genotypic and phylogenetic data, strain YIM ART13Trepresents a novel species of the genus Nocardioides, for which the name Nocardioides speluncae sp. nov. is proposed. The type strain is YIM ART13T (= KCTC 39593T = DSM 100493T).