Search Results for: microbiolog

Author: Rasmussen, T.B.; Givskov, M. Description: Quorum-sensing (QS) signalling systems of pathogens are central regulators for the expression of virulence factors and represent highly attractive targets for the development of novel therapeutics. In Pseudomonas aeruginosa, QS systems are also involved in elevated antibiotic tolerance of biofilms as well as elevated tolerance to the activity of the innate immune system. Gram-negative bacteria commonly use N-acyl homoserine lactones (AHL) as QS signal molecules. The use of signal molecule based drugs to attenuate bacterial pathogenecity rather than bacterial growth is attractive for several…

Author: Lam, S.J.; O’Brien-Simpson, N.M.; Pantarat, N.; Sulistio, A.; Wong, E.H.H.; Chen, Y.-Y.; Lenzo, J.C.; Holden, J.A.; Blencowe, A.; Reynolds, E.C.; Qiao, G.G. Description: With the recent emergence of reports on resistant Gram-negative ‘superbugs’, infections caused by multidrug-resistant (MDR) Gram-negative bacteria have been named as one of the most urgent global health threats due to the lack of effective and biocompatible drugs. Here, we show that a class of antimicrobial agents, termed ‘structurally nanoengineered antimicrobial peptide polymers’ (SNAPPs) exhibit sub-muM activity against all Gram-negative bacteria tested, including ESKAPE and colistin-resistant…

Author: Nicolaou, S.A.; Gaida, S.M.; Papoutsakis, E.T. Description: Metabolites, substrates and substrate impurities may be toxic to cells by damaging biological molecules, organelles, membranes or disrupting biological processes. Chemical stress is routinely encountered in bioprocessing to produce chemicals or fuels from renewable substrates, in whole-cell biocatalysis and bioremediation. Cells respond, adapt and may develop tolerance to chemicals by mechanisms only partially explored, especially for multiple simultaneous stresses. More is known about how cells respond to chemicals, but less about how to develop tolerant strains. Aiming to stimulate new metabolic engineering…

Author: Baker-Austin, C.; Wright, M.S.; Stepanauskas, R.; McArthur, J.V. Description: There is growing concern that metal contamination functions as a selective agent in the proliferation of antibiotic resistance. Documented associations between the types and levels of metal contamination and specific patterns of antibiotic resistance suggest that several mechanisms underlie this co-selection process. These co-selection mechanisms include co-resistance (different resistance determinants present on the same genetic element) and cross-resistance (the same genetic determinant responsible for resistance to antibiotics and metals). Indirect but shared regulatory responses to metal and antibiotic exposure such…

Author: Bai, X.; Ma, X.; Xu, F.; Li, J.; Zhang, H.; Xiao, X. Description: Two waterworks, with source water derived from the Huangpu or Yangtze River in Shanghai, were investigated, and the effluents were plate-screened for antibiotic-resistant bacteria (ARB) using five antibiotics: ampicillin (AMP), kanamycin (KAN), rifampicin (RFP), chloramphenicol (CM) and streptomycin (STR). The influence of water treatment procedures on the bacterial antibiotic resistance rate and the changes that bacteria underwent when exposed to the five antibiotics at concentration levels ranging from 1 to 100 mug/mL were studied. Multi-drug resistance…

Author: Joshi, A.; Kostiuk, B.; Rogers, A.; Teschler, J.; Pukatzki, S.; Yildiz, F.H. Description: Microbial species often exist in complex communities where they must avoid predation and compete for favorable niches. The type VI secretion system (T6SS) is a contact-dependent bacterial weapon that allows for direct killing of competitors through the translocation of proteinaceous toxins. Vibrio cholerae is a Gram-negative pathogen that can use its T6SS during antagonistic interactions with neighboring prokaryotic and eukaryotic competitors. The T6SS not only promotes V. cholerae’s survival during its aquatic and host life cycles,…

Author: Prince, B.T.; Mandel, M.J.; Nadeau, K.; Singh, A.M. Description: The impact of gut microbiome on human development, nutritional needs, and disease has become evident with advances in the ability to study these complex communities of microorganisms, and there is growing appreciation for the role of the microbiome in immune regulation. Several studies have examined associations between changes in the commensal microbiota and the development of asthma, allergic rhinitis, and asthma, but far less have evaluated the impact of the microbiome on the development of food allergy. This article reviews…

Author: Klatt, N.R.; Cheu, R.; Birse, K.; Zevin, A.S.; Perner, M.; Noel-Romas, L.; Grobler, A.; Westmacott, G.; Xie, I.Y.; Butler, J.; Mansoor, L.; McKinnon, L.R.; Passmore, J.-A.S.; Abdool Karim, Q.; Abdool Karim, S.S.; Burgener, A.D. Description: Antiretroviral-based strategies for HIV prevention have shown inconsistent results in women. We investigated whether vaginal microbiota modulated tenofovir gel microbicide efficacy in the CAPRISA (Centre for the AIDS Program of Research in South Africa) 004 trial. Two major vaginal bacterial community types-one dominated by Lactobacillus (59.2%) and the other where Gardnerella vaginalis predominated with…

Author: Wilson, D.N. Description: The ribosome is one of the main antibiotic targets in the bacterial cell. Crystal structures of naturally produced antibiotics and their semi-synthetic derivatives bound to ribosomal particles have provided unparalleled insight into their mechanisms of action, and they are also facilitating the design of more effective antibiotics for targeting multidrug-resistant bacteria. In this Review, I discuss the recent structural insights into the mechanism of action of ribosome-targeting antibiotics and the molecular mechanisms of bacterial resistance, in addition to the approaches that are being pursued for the…

Author: Hong, K.-J.; Lee, C.-H.; Kim, S.W. Description: This study evaluated the effect of fermentation on the nutritional quality of food-grade soybeans and feed-grade soybean meals. Soybeans and soybean meals were fermented by Aspergillus oryzae GB-107 in a bed-packed solid fermentor for 48 hours. After fermentation, their nutrient contents as well as trypsin inhibitor were measured and compared with those of raw soybeans and soybean meals. Proteins were extracted from fermented and non-fermented soybeans and soybean meals, and the peptide characteristics were evaluated after electrophoresis. Fermented soybeans and fermented soybean…