Ιατρικά Άρθρα Αλέξανδρος Γ. Σφακιανάκης

Previously, it has been reported that a novel PepGel (h9e peptide) can be triggered into a solid physical hydrogel by the addition of selected ions and proteins for various biomedical applications. Moreover, PepGel displays shear-thinning and repeatedly reversible sol–gel transfer properties that enable it to be easily transferred via an injector. In this study, PepGel is proposed as a carrier for controlled releases of bovine serum albumin (BSA)-bound or -linked drugs. BSA-linked cisplatin (BSA–CP) is used as a model drug in this study and plays two roles: as a trigger of hydrogel and as a target drug for controlled release. Results of fluorescence instrument show that PepGel significantly quenches the fluorescence of Trp in the hydrophobic subdomain of BSA, indicating a strong interaction. Images of TEM and fluorescence confocal microscopy indicate that BSA–CP is dispersed in the PepGel fibers and at the same time enhances the fiber aggregation. Through UV instrument, it is found that PepGel can effectively inhibit the diffusion of BSA–CP even at concentrations below 0.3 wt% and that the rate of BSA–CP release could be controlled by adjusting the concentration of PepGel. Cell culture studies on the performance of the PepGel are carried out using HeLa cells, and the cell viability is observed to be consistent with the data of drug release. The results showed that PepGel nanofiber scaffolds could potentially be used as an effective carrier for controlled releases of BSA-bound or -linked drugs.

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An Ethical Dilemma: To Share or Not To Share Your Paper Published in Lipids Using an On-Line Outlet

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Bdm-Mediated Regulation of Flagellar Biogenesis in Escherichia coli and Salmonella enterica Serovar Typhimurium

Abstract

Synthesis of the flagellar apparatus in Escherichia coli is mediated via complex regulatory pathways. A previous study indicated that the protein encoded by the biofilm-dependent modulation (bdm) gene is linked closely with a regulatory pathway for flagellar assembly. However, the specific role of Bdm in flagellar biogenesis remains unknown. Herein, we showed that Bdm interacts with FlgM and inhibits its function as an anti-σ28 factor, which induces the transcription of flagellar late-class genes in E. coli. In addition, we observed that deletion of the yddX gene, a potential Salmonella enterica serovar Typhimurium homolog of bdm, also resulted in downregulation of flagellar late-class genes and in the formation of short flagella, leading to decreased virulence in mice. The expression levels of late-class flagellar genes in yddX-deleted S. Typhimurium cells were restored to those of the wild type when either E. coli bdm or S. Typhimurium yddX was expressed exogenously. These results suggest that Bdm-mediated regulation of flagellar assembly is a conserved regulatory pathway in those members of the Enterobacteriaceae family whose genomes show the existence of homologs of bdm.

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ATP Sulfurylase is Essential for the Utilization of Sulfamate as a Sulfur Source in the Yeast Komagataella pastoris (syn. Pichia pastoris )

Abstract

The methylotrophic yeast Komagataella pastoris (syn. Pichia pastoris) is one of the few known yeasts that can utilize sulfamate ( \({\text{NH}}_{2} {\text{SO}}_{3}^{ - }\) ) as a sulfur source. The biochemical pathway responsible for the catabolism of sulfamate has yet to be identified. The present study sought to investigate whether sulfamate catabolism proceeds through either of the inorganic sulfur intermediates sulfate ( \({\text{SO}}_{4}^{2 - }\) ) or sulfite ( \({\text{SO}}_{3}^{2 - }\) ) before its assimilation and subsequent incorporation into sulfur-containing amino acids and their derivatives. Two key genes in the K. pastoris inorganic sulfur assimilation pathway were deleted separately and the ability of each deletion mutant to utilize sulfamate and other selected sulfur sources was studied. Deletion of the MET3 gene (which encodes the enzyme ATP sulfurylase) did not affect growth on l-methionine, sulfite, methanesulfonate, or taurine but completely abolished growth on sulfate, methyl sulfate and sulfamate. Deletion of the MET5 gene (which encodes the β subunit of the enzyme sulfite reductase) abolished growth on all tested sulfur sources except l-methionine. These results suggest that the catabolism of sulfamate proceeds through a sulfate intermediate before its assimilation.

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Ιατρικά Άρθρα Αλέξανδρος Γ. Σφακιανάκης

Πληροφορίες

Κυριακή 11 Ιουνίου 2017

Hyperspectral X-ray transmission imaging................................3D chemical imaging

Persistent lesion hyperintensity on brain diffusion-weighted MRI

Nausea, vomiting, loss of appetite and oliguria : haemoglobin =12.7 g/dL, indirect bilirubin =2.0 mg/dL, haptoglobin ≤6 mg/dL, platelet count =121 000/μL and schistocytes on peripheral smear.

Controlled release of BSA-linked cisplatin through a PepGel self-assembling peptide nanofiber hydrogel scaffold

Abstract

An Ethical Dilemma: To Share or Not To Share Your Paper Published in Lipids Using an On-Line Outlet

Bdm-Mediated Regulation of Flagellar Biogenesis in Escherichia coli and Salmonella enterica Serovar Typhimurium

Abstract

ATP Sulfurylase is Essential for the Utilization of Sulfamate as a Sulfur Source in the Yeast Komagataella pastoris (syn. Pichia pastoris )

Abstract

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