The type VI secretion system (T6SS) is a powerful tool deployed by Gram-negative bacteria to antagonize neighboring organisms. Here, we report that ATCC 17978 (Ab17978) secretes D-lysine (D-Lys), increasing the extracellular pH and enhancing the peptidoglycanase activity of the T6SS effector Tse4. This synergistic effect of D-Lys on Tse4 activity enables Ab17978 to outcompete Gram-negative bacterial competitors, demonstrating that bacteria can modify their microenvironment to increase their fitness during bacterial warfare. Remarkably, this lethal combination also results in T6SS-mediated killing of Gram-positive bacteria. Further characterization revealed that Tse4 is a bifunctional enzyme consisting of both lytic transglycosylase and endopeptidase activities, thus representing a family of modularly organized T6SS peptidoglycan-degrading effectors with an unprecedented impact in antagonistic bacterial interactions.
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http://dx.doi.org/10.1073/pnas.2106555118 | DOI Listing |
Foot Ankle Spec
January 2025
Department of Trauma Surgery, Northwest Clinics, Alkmaar, the Netherlands.
Surgical site infections (SSIs) are the most common complication after surgery for ankle fractures. This retrospective study aimed to determine the pathogens cultured in SSI and their antimicrobial susceptibility patterns to provide a recommendation for empirical therapy. Patients who underwent surgical treatment for an ankle fracture were included.
View Article and Find Full Text PDFProtein Sci
February 2025
Department of Chemistry, Institute of Biochemistry, BOKU University, Vienna, Austria.
Prokaryotic heme biosynthesis in Gram-positive bacteria follows the coproporphyrin-dependent heme biosynthesis pathway. The last step in this pathway is catalyzed by the enzyme coproheme decarboxylase, which oxidatively transforms two propionate groups into vinyl groups yielding heme b. The catalytic reaction cycle of coproheme decarboxylases exhibits four different states: the apo-form, the substrate (coproheme)-bound form, a transient three-propionate intermediate form (monovinyl, monopropionate deuteroheme; MMD), and the product (heme b)-bound form.
View Article and Find Full Text PDFMicrob Cell Fact
January 2025
Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, Amsterdam, 1098 XH, The Netherlands.
Background: Ribosome pausing slows down translation and can affect protein synthesis. Improving translation efficiency can therefore be of commercial value. In this study, we investigated whether ribosome pausing occurs during production of the α-amylase AmyM by the industrial production organism Bacillus subtilis under repeated batch fermentation conditions.
View Article and Find Full Text PDFBMC Microbiol
January 2025
State Key Laboratory of Oral Diseases, West China School of Stomatology, National Clinical Research Center for Oral Diseases, Sichuan University, Chengdu, China.
Background: Streptococcus mutans is recognized as a key pathogen responsible for the development of dental caries. With the advancement of research on dental caries, the understanding of its pathogenic mechanism has gradually shifted from the theory of a single pathogenic bacterium to the theory of oral microecological imbalance. Acidogenic and aciduric microbial species are also recognized to participate in the initiation and progression of dental caries.
View Article and Find Full Text PDFWorld J Microbiol Biotechnol
January 2025
Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, 72 Binhai Road, Jimo, Qingdao, 266237, China.
Catabolic plasmids are critical factors in the degradation of recalcitrant xenobiotics, such as dioxins. Understanding the persistence and evolution of native catabolic plasmids is pivotal for controlling their function in microbial remediation. Here, we track the fitness and evolution of Rhodococcus sp.
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