Lytic transglycosylase repertoire diversity enables intrinsic antibiotic resistance and daughter cell separation in under acidic stress.

Peptidoglycan (PG) is an important architectural element that imparts physical toughness and rigidity to the bacterial envelope. It is also a dynamic structure that undergoes continuous turnover or autolysis. possesses redundant PG degradation enzymes responsible for PG turnover; however, the advantage afforded by the existence of numerous PG degradation enzymes remains incompletely understood.

Biological production of epicoccamide-aglycone and its cytotoxicity.

Epicoccamide (EPC) is an O-d-mannosylated acyltetramic acid of Epicoccum origin and is a bolaamphiphilic fungal polyketide. EPC displays weak toxicity against Staphylococcus aureus and HeLa cell lines. The EPC biosynthetic gene cluster was previously identified in Epicoccum nigrum and knockout of the glycosyltransferase gene (epcB) abolished EPC production.

Rapid Assembly of Pyrrole-Ligated 1,3,4-Oxadiazoles and Excellent Antibacterial Activity of Iodophenol Substituents.

Pyrrole-ligated 1,3,4-oxadiazole is a very important pharmacophore which exhibits broad therapeutic effects such as anti-tuberculosis, anti-epileptic, anti-HIV, anti-cancer, anti-inflammatory, antioxidant, and antibacterial activities. A one-pot Maillard reaction between D-Ribose and an L-amino methyl ester in DMSO with oxalic acid at 2.5 atm and 80 °C expeditiously produced pyrrole-2-carbaldehyde platform chemicals in reasonable yields, which were utilized for the synthesis of pyrrole-ligated 1,3,4-oxadiazoles.

Coordinated and Distinct Roles of Peptidoglycan Carboxypeptidases DacC and DacA in Cell Growth and Shape Maintenance under Stress Conditions.

Peptidoglycan (PG) is an essential bacterial architecture pivotal for shape maintenance and adaptation to osmotic stress. Although PG synthesis and modification are tightly regulated under harsh environmental stresses, few related mechanisms have been investigated. In this study, we aimed to investigate the coordinated and distinct roles of the PG dd-carboxypeptidases (DD-CPases) DacC and DacA in cell growth under alkaline and salt stresses and shape maintenance in Escherichia coli.

Divergent Effects of Peptidoglycan Carboxypeptidase DacA on Intrinsic β-Lactam and Vancomycin Resistance.

Vancomycin and β-lactams are clinically important antibiotics that inhibit the formation of peptidoglycan cross-links, but their binding targets are different. The binding target of vancomycin is d-alanine-d-alanine (d-Ala-d-Ala), whereas that of β-lactam is penicillin-binding proteins (PBPs). In this study, we revealed the divergent effects of peptidoglycan (PG) carboxypeptidase DacA on vancomycin and β-lactam resistance in Escherichia coli and Bacillus subtilis.

Distinct Amino Acid Availability-Dependent Regulatory Mechanisms of MepS and MepM Levels in .

Peptidoglycan (PG) hydrolases play important roles in various aspects of bacterial physiology, including cytokinesis, PG synthesis, quality control of PG, PG recycling, and antibiotic resistance. However, the regulatory mechanisms of their expression are poorly understood. In this study, we have uncovered novel regulatory mechanisms of the protein levels of the synthetically lethal PG endopeptidases MepS and MepM, which are involved in PG synthesis.

Phenotypic characterization of a conserved inner membrane protein YhcB in Escherichia coli.

Although bacteria have diverse membrane proteins, the function of many of them remains unknown or uncertain even in Escherichia coli. In this study, to investigate the function of hypothetical membrane proteins, genome-wide analysis of phenotypes of hypothetical membrane proteins was performed under various envelope stresses. Several genes responsible for adaptation to envelope stresses were identified.

Distinct Roles of Outer Membrane Porins in Antibiotic Resistance and Membrane Integrity in .

A defining characteristic of Gram-negative bacteria is the presence of an outer membrane, which functions as an additional barrier inhibiting the penetration of toxic chemicals, such as antibiotics. Porins are outer membrane proteins associated with the modulation of cellular permeability and antibiotic resistance. Although there are numerous studies regarding porins, a systematic approach about the roles of porins in bacterial physiology and antibiotic resistance does not exist yet.

Characterization of a Novel Neoagarobiose-Producing GH42 β-Agarase, AgaJ10, from Gayadomonas joobiniege G7.

Gayadomonas joobiniege G7 is an agar-degrading bacterium, which produces various agarases that have been biochemically characterized recently. In this study, we biochemically characterized a new β-agarase AgaJ10 belonging to the glycoside hydrolase (GH) 42 family from G. joobiniege G7.

Antimicrobial Agents That Inhibit the Outer Membrane Assembly Machines of Gram-Negative Bacteria.

Gram-negative pathogens, such as , , and , pose a serious threat to public health worldwide, due to high rates of antibiotic resistance and the lack of development of novel antimicrobial agents targeting Gram-negative bacteria. The outer membrane (OM) of Gram-negative bacteria is a unique architecture that acts as a potent permeability barrier against toxic molecules, such as antibiotics. The OM is composed of phospholipids, lipopolysaccharide (LPS), outer membrane β-barrel proteins (OMP), and lipoproteins.

Effect of the RNA pyrophosphohydrolase RppH on envelope integrity in Escherichia coli.

The bacterial enzyme RppH initiates mRNA decay by removing pyrophosphate from 5΄-triphosphorylated mRNA. Escherichia coli RppH has promiscuous substrate specificity, but relatively few transcripts are affected by loss of RppH. The phenotypic analysis of the rppH mutant is required for understanding the physiological role of RppH, but the phenotype of the rppH mutant has not yet been determined.

Increased expression of genes involved in uptake and degradation of murein tripeptide under nitrogen starvation in Escherichia coli.

Peptidoglycan (also known as murein) is an important envelope component of bacteria, and its turnover usually takes place at considerable levels during normal growth. Amino sugars and murein tripeptide resulting from murein degradation are used for resynthesis of peptidoglycan or as self-generated nutrients or energy sources for cell growth. PgrR (regulator of peptide glycan recycling; formerly YcjZ) was recently identified as a repressor of several genes participating in uptake and degradation of murein tripeptide.