The action of a sporulation-specific seryl protease on antibiotic-free extracts of Bacillus licheniformis cells yields a peptide that is identified as bacitracin by its biological activity, its spectral properties, and its comigration with genuine bacitracin in both paper and thin-layer chromatography. During proteolysis, a chemical structure is generated with the spectral properties of a delta-2 thiazoline ring. The yield in vitro, 4 microgram of bacitracin per mg of protein, is less than the maximal yield from sporulating cells, 75 microgram of bacitracin per mg of cell protein, but is a linear function of the amount of protein in the reaction system. Approximately 30% of the protein yielding the antibiotic is ribosomal associated, and only 25% of that amount can be removed by washing with 1 M NH4Cl. The substrate protein is a constant fraction of the cell protein throughout exponential growth and very early sporulation stages of culture development.
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http://dx.doi.org/10.1128/jb.131.3.897-905.1977 | DOI Listing |
JCI Insight
January 2025
CNRS UMR 5164, INSERM ERL 1303, ImmunoConcEpT, University of Bordeaux, Bordeaux, France.
CD8+ T cells are critical for immune protection against severe COVID-19 during acute infection with SARS-CoV-2. However, the induction of antiviral CD8+ T cell responses varies substantially among infected people, and a better understanding of the mechanisms that underlie such immune heterogeneity is required for pandemic preparedness and risk stratification. In this study, we analyzed SARS-CoV-2-specific CD4+ and CD8+ T cell responses in relation to age, clinical status, and inflammation among patients infected primarily during the initial wave of the pandemic in France or Japan.
View Article and Find Full Text PDFTransl Vis Sci Technol
January 2025
Department of Ophthalmology, Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
Purpose: Regulating intraocular pressure (IOP), mainly via the trabecular meshwork (TM), is critical in developing glaucoma. Whereas current treatments aim to lower IOP, directly targeting the dysfunctional TM tissue for therapeutic intervention has proven challenging. In our study, we utilized Dexamethasone (Dex)-treated TM cells as a model to investigate how extracellular vesicles (EVs) from immortalized corneal stromal stem cells (imCSSCs) could influence ANGPTL7 and MYOC genes expression within TM cells.
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
January 2025
Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan.
Purpose: To investigate the effect of Rho-associated protein kinase (ROCK) inhibitor Y27632 on bioenergetic capacity and resilience of corneal endothelial cells (CECs) under metabolic stress.
Methods: Bovine CECs (BCECs) were treated with Y27632 and subjected to bioenergetic profiling using the Seahorse XFp Analyzer. The effects on adenosine triphosphate (ATP) production through oxidative phosphorylation and glycolysis were measured.
Invest Ophthalmol Vis Sci
January 2025
Wilmer Eye Institute, Johns Hopkins Medical Institute, Baltimore, Maryland, United States.
Purpose: Although mechanical injury to the cornea (e.g. chronic eye rubbing) is a known risk factor for keratoconus progression, how it contributes to loss of corneal integrity is not known.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Max Perutz Labs, Vienna Biocenter Campus, Vienna 1030, Austria.
RNA G-quadruplexes (rG4s), the four-stranded structures formed by guanine-rich RNA sequences, are recognized by regions in RNA-binding proteins (RBPs) that are enriched in arginine-glycine repeats (RGG motifs). Importantly, arginine and glycine are encoded by guanine-rich codons, suggesting that some RGG motifs may both be encoded by and interact with rG4s in autogenous messenger RNAs (mRNAs). By analyzing transcriptome-wide rG4 datasets, we show that hundreds of RGG motifs in humans are at least partly encoded by rG4s, with an increased incidence for longer RGG motifs (~10 or more residues).
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