The target range of a bacterial secretion system can be defined by effector substrate specificity or by the efficacy of effector delivery. Here, we report the crystal structure of Tse1, a type VI secretion (T6S) bacteriolytic amidase effector from Pseudomonas aeruginosa. Consistent with its role as a toxin, Tse1 has a more accessible active site than related housekeeping enzymes. The activity of Tse1 against isolated peptidoglycan shows its capacity to act broadly against Gram-negative bacteria and even certain Gram-positive species. Studies with intact cells indicate that Gram-positive bacteria can remain vulnerable to Tse1 despite cell wall modifications. However, interbacterial competition studies demonstrate that Tse1-dependent lysis is restricted to Gram-negative targets. We propose that the previously observed specificity for T6S against Gram-negative bacteria is a consequence of high local effector concentration achieved by T6S-dependent targeting to its site of action rather than inherent effector substrate specificity.
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http://dx.doi.org/10.1016/j.celrep.2012.05.016 | DOI Listing |
Sci Rep
January 2025
Department of Clinical Laboratory, Children's Hospital of Fudan University, National Children's Medical Center, 399 Wanyuan Rd, Minhang District, Shanghai, 201102, China.
China has adhered to policies of zero-COVID for almost three years since the outbreak of COVID-19, which has remarkably affected the circulation of respiratory pathogens. However, China has begun to end the zero-COVID policies in late 2022. Here, we reported a resurgence of common respiratory viruses and Mycoplasma pneumoniae with unique epidemiological characteristics among children after ending the zero-COVID policy in Shanghai, China, 2023.
View Article and Find Full Text PDFCell Commun Signal
January 2025
Beijing An Zhen Hospital, Capital Medical University, The Key Laboratory of Remodeling Cardiovascular Diseases, Ministry of Education; Collaborative Innovation Center for Cardiovascular Disorders, Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing, 100029, China.
Background: The potential role of Klebsiella pneumoniae (K.pn) in hypertension development has been emphasized, although the specific mechanisms have not been well understood. Bacterial extracellular vesicles (BEVs) released by Gram-negative bacteria modulate host cell functions by delivering bacterial components to host cells.
View Article and Find Full Text PDFJ Ethnopharmacol
January 2025
Jiangxi Key Laboratory of Natural Product and Functional Food, College of Food Science and Engineering, Jiangxi Agricultural University, Nanchang 330045, China. Electronic address:
Ethnopharmacological Relevance: As an important component of the cell wall of Gram-negative bacteria, lipopolysaccharide (LPS) is an important inducer of inflammation in humans. Smilax china L. is known for its diverse bioactive functions, particularly its anti-inflammatory effects.
View Article and Find Full Text PDFJ Comp Pathol
January 2025
Histologia i Anatomia Patològica, Facultat de Veterinària (UAB), 08193 Bellaterra (Barcelona), Spain.
Nocardia spp are ubiquitous, gram-positive, variably acid-fast, branching and beaded filamentous, facultative intracellular bacteria that are resistant to phagocytosis and can cause localized or systemic disease in a variety of mammals, including humans, as well as in birds, fish and reptiles. Seventeen pet domestic ferrets (Mustela putorius furo) were diagnosed with nocardiosis by several methods including cytological evaluation, histopathology, Ziehl-Neelsen staining and polymerase chain reaction (PCR). All except two ferrets were 2 years old or older at the time of clinical presentation.
View Article and Find Full Text PDFArch Microbiol
January 2025
Department of Botany, CMS College Kottayam, Kottayam, Kerala, 686001, India.
Among all photosynthetic life forms, cyanobacteria exclusively possess a water-soluble, light-sensitive carotenoprotein complex known as orange carotenoid proteins (OCPs), crucial for their photoprotective mechanisms. These protein complexes exhibit both structural and functional modularity, with distinct C-terminal (CTD) and N-terminal domains (NTD) serving as light-responsive sensor and effector regions, respectively. The majority of cyanobacterial genomes contain genes for OCP homologs and related proteins, highlighting their essential role in survival of the organism over time.
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