journal
https://read.qxmd.com/read/38421161/mutation-of-wbtj-a-n-formyltransferase-involved-in-o-antigen-synthesis-results-in-biofilm-formation-phase-variation-and-attenuation-in-francisella-tularensis
#1
JOURNAL ARTICLE
Kevin D Mlynek, Ronald G Toothman, Elsie E Martinez, Ju Qiu, Joshua B Richardson, Joel A Bozue
Two clinically important subspecies, Francisella tularensis subsp. tularensis (type A) and F. tularensis subsp. holarctica (type B) are responsible for most tularaemia cases, but these isolates typically form a weak biofilm under in vitro conditions. Phase variation of the F. tularensis lipopolysaccharide (LPS) has been reported in these subspecies, but the role of variation is unclear as LPS is crucial for virulence. We previously demonstrated that a subpopulation of LPS variants can constitutively form a robust biofilm in vitro, but it is unclear whether virulence was affected...
February 2024: Microbiology
https://read.qxmd.com/read/38385784/ecological-dependencies-and-the-illusion-of-cooperation-in-microbial-communities
#2
JOURNAL ARTICLE
Elze Hesse, Siobhán O'Brien
Ecological dependencies - where organisms rely on other organisms for survival - are a ubiquitous feature of life on earth. Multicellular hosts rely on symbionts to provide essential vitamins and amino acids. Legume plants similarly rely on nitrogen-fixing rhizobia to convert atmospheric nitrogen to ammonia. In some cases, dependencies can arise via loss-of-function mutations that allow one partner to benefit from the actions of another. It is common in microbiology to label ecological dependencies between species as cooperation - making it necessary to invoke cooperation-specific frameworks to explain the phenomenon...
February 2024: Microbiology
https://read.qxmd.com/read/38376387/-shigella-sonnei-utilises-colicins-during-inter-bacterial-competition
#3
JOURNAL ARTICLE
P B Leung, X M Matanza, B Roche, K P Ha, H C Cheung, S Appleyard, T Collins, O Flanagan, B S Marteyn, A Clements
The mammalian colon is one of the most densely populated habitats currently recognised, with 1011 -1013 commensal bacteria per gram of colonic contents. Enteric pathogens must compete with the resident intestinal microbiota to cause infection. Among these enteric pathogens are Shigella species which cause approximately 125 million infections annually, of which over 90 % are caused by Shigella flexneri and Shigella sonnei. Shigella sonnei was previously reported to use a Type VI Secretion System (T6SS) to outcompete E...
February 2024: Microbiology
https://read.qxmd.com/read/38373028/p-type-atpase-zinc-transporter-rv3270-of-mycobacterium-tuberculosis-enhances-multi-drug-efflux-activity
#4
JOURNAL ARTICLE
Debasmita Chatterjee, Aditya Prasad Panda, A R Daya Manasi, Anindya S Ghosh
Metal homeostasis is maintained by the uptake, storage and efflux of metal ions that are necessary for the survival of the bacterium. Homeostasis is mostly regulated by a group of transporters categorized as ABC transporters and P-type ATPases. On the other hand, efflux pumps often play a role in drug-metal cross-resistance. Here, with the help of antibiotic sensitivity, antibiotic/dye accumulation and semi-quantitative biofilm formation assessments we report the ability of Rv3270, a P-type ATPase known for its role in combating Mn2+ and Zn2+ metal ion toxicity in Mycobacterium tuberculosis , in influencing the extrusion of multiple structurally unrelated drugs and enhancing the biofilm formation of Escherichia coli and Mycobacterium smegmatis...
February 2024: Microbiology
https://read.qxmd.com/read/38363712/identification-of-novel-tail-anchored-membrane-proteins-integrated-by-the-bacterial-twin-arginine-translocase
#5
JOURNAL ARTICLE
José Jesús Gallego-Parrilla, Emmanuele Severi, Govind Chandra, Tracy Palmer
The twin-arginine protein transport (Tat) system exports folded proteins across the cytoplasmic membranes of prokaryotes and the energy transducing-membranes of plant thylakoids and mitochondria. Proteins are targeted to the Tat machinery by N-terminal signal peptides with a conserved twin-arginine motif, and some substrates are exported as heterodimers where the signal peptide is present on one of the partner proteins. A subset of Tat substrates is found in the membrane. Tat-dependent membrane proteins usually have large globular domains and a single transmembrane helix present at the N- or C-terminus...
February 2024: Microbiology
https://read.qxmd.com/read/38363121/twists-and-turns-40-years-of-investigating-how-and-why-bacteria-swim
#6
JOURNAL ARTICLE
Judith P Armitage
Fifty years of research has transformed our understanding of bacterial movement from one of description, based on a limited number of electron micrographs and some low-magnification studies of cells moving towards or away from chemical effectors, to probably the best understood behavioural system in biology. We have a molecular understanding of how bacteria sense and respond to changes in their environment and detailed structural insights into the workings of one of the most complex motor structures we know of...
February 2024: Microbiology
https://read.qxmd.com/read/38358391/molecular-insights-into-the-determinants-of-substrate-specificity-and-efflux-inhibition-of-the-rnd-efflux-pumps-acrb-and-adeb
#7
JOURNAL ARTICLE
Julia Wilhelm, Klaas Martinus Pos
Gram-negative bacterial members of the Resistance Nodulation and cell Division (RND) superfamily form tripartite efflux pump systems that span the cell envelope. One of the intriguing features of the multiple drug efflux members of this superfamily is their ability to recognize different classes of antibiotics, dyes, solvents, bile salts, and detergents. This review provides an overview of the molecular mechanisms of multiple drug efflux catalysed by the tripartite RND efflux system AcrAB-TolC from Eschericha coli ...
February 2024: Microbiology
https://read.qxmd.com/read/38358321/predatory-bacteria-prevent-the-proliferation-of-intraocular-serratia-marcescens-and-fluoroquinolone-resistant-pseudomonas-aeruginosa
#8
JOURNAL ARTICLE
Eric G Romanowski, Kimberly M Brothers, Rachel C Calvario, Nicholas A Stella, Tami Kim, Mennat Elsayed, Daniel E Kadouri, Robert M Q Shanks
Endogenous endophthalmitis caused by Gram-negative bacteria is an intra-ocular infection that can rapidly progress to irreversible loss of vision. While most endophthalmitis isolates are susceptible to antibiotic therapy, the emergence of resistant bacteria necessitates alternative approaches to combat intraocular bacterial proliferation. In this study the ability of predatory bacteria to limit intraocular growth of Pseudomonas aeruginosa , Serratia marcescens , and Staphylococcus aureus was evaluated in a New Zealand white rabbit endophthalmitis prevention model...
February 2024: Microbiology
https://read.qxmd.com/read/38334478/structure-and-ligand-binding-in-the-putative-anti-microbial-peptide-transporter-protein-yeja
#9
JOURNAL ARTICLE
Bryony K Ackroyd, Eleanor J Dodson, Javeria Mehboob, Adam A Dowle, Gavin H Thomas, Anthony J Wilkinson
YejABEF is an ATP-binding cassette transporter that is implicated in the sensitivity of Escherichia coli to anti-microbial peptides, the best-characterized example being microcin C, a peptide-nucleotide antibiotic that targets aspartyl-tRNA synthetase. Here the structure of the extracellular solute binding protein, YejA, has been determined, revealing an oligopeptide-binding protein fold enclosing a ligand-binding pocket larger than those of other peptide-binding proteins of known structure. Prominent electron density in this cavity defines an undecapeptide sequence LGEPRYAFNFN, an observation that is confirmed by mass spectrometry...
February 2024: Microbiology
https://read.qxmd.com/read/38329407/microbial-primer-bacterial-growth-kinetics
#10
JOURNAL ARTICLE
Lorena T Fernández-Martínez, Arnaud Javelle, Paul A Hoskisson
tGrowth of microorganisms and interpretation of growth data are core skills required by microbiologists. While science moves forward, it is of paramount importance that essential skills are not lost. The bacterial growth curve and the information that can gleaned from it is of great value to all of microbiology, whether this be a simple growth experiment, comparison of mutant strains or the establishment of conditions for a large-scale multi-omics experiment. Increasingly, the basics of plotting and interpreting growth curves and growth data are being overlooked...
February 2024: Microbiology
https://read.qxmd.com/read/38314762/current-understandings-of-colibactin-regulation
#11
JOURNAL ARTICLE
Emily Addington, Sofia Sandalli, Andrew J Roe
The biosynthetic machinery for the production of colibactin is encoded by 19 genes ( clbA - S ) within the pks pathogenicity island harboured by many E. coli of the B2-phylogroup. Colibactin is a potent genotoxic metabolite which causes DNA-damage and which has potential roles in microbial competition and fitness of pks + bacteria. Colibactin has also been strongly implicated in the development of colorectal cancer. Given the genotoxicity of colibactin and the metabolic cost of its synthesis, the regulatory system governing the clb cluster is accordingly highly complex, and many of the mechanisms remain to be elucidated...
February 2024: Microbiology
https://read.qxmd.com/read/38289644/construction-and-characterisation-of-a-structured-tuneable-and-transparent-3d-culture-platform-for-soil-bacteria
#12
JOURNAL ARTICLE
Liam M Rooney, Lionel X Dupuy, Paul A Hoskisson, Gail McConnell
We have developed a tuneable workflow for the study of soil microbes in an imitative 3D soil environment that is compatible with routine and advanced optical imaging, is chemically customisable, and is reliably refractive index matched based on the carbon catabolism of the study organism. We demonstrate our transparent soil pipeline with two representative soil organisms, Bacillus subtilis and Streptomyces coelicolor , and visualise their colonisation behaviours using fluorescence microscopy and mesoscopy. This spatially structured, 3D approach to microbial culture has the potential to further study the behaviour of bacteria in conditions matching their native environment and could be expanded to study microbial interactions, such as competition and warfare...
January 2024: Microbiology
https://read.qxmd.com/read/38261525/time-lapse-mesoscopy-of-candida-albicans-and-staphylococcus-aureus-dual-species-biofilms-reveals-a-structural-role-for-the-hyphae-of-c-albicans-in-biofilm-formation
#13
JOURNAL ARTICLE
Katherine J Baxter, Fiona A Sargison, J Ross Fitzgerald, Gail McConnell, Paul A Hoskisson
Polymicrobial infection with Candida albicans and Staphylococcus aureus may result in a concomitant increase in virulence and resistance to antimicrobial drugs. This enhanced pathogenicity phenotype is mediated by numerous factors, including metabolic processes and direct interaction of S. aureus with C. albicans hyphae. The overall structure of biofilms is known to contribute to their recalcitrance to treatment, although the dynamics of direct interaction between species and how it contributes to pathogenicity is poorly understood...
January 2024: Microbiology
https://read.qxmd.com/read/38226962/microbial-primer-the-bacterial-flagellum-how-bacteria-swim
#14
JOURNAL ARTICLE
Judith P Armitage
Bacteria swim using membrane-spanning, electrochemical gradient-powered motors that rotate semi-rigid helical filaments. This primer provides a brief overview of the basic synthesis, structure and operation of these nanomachines. Details and variations on the basic system can be found in suggested further reading.
January 2024: Microbiology
https://read.qxmd.com/read/38193814/a-toolbox-for-manipulating-the-genome-of-the-major-goat-pathogen-mycoplasma-capricolum-subsp-capripneumoniae
#15
JOURNAL ARTICLE
Géraldine Gourgues, Lucía Manso-Silván, Catherine Chamberland, Pascal Sirand-Pugnet, François Thiaucourt, Alain Blanchard, Vincent Baby, Carole Lartigue
Mycoplasma capricolum subspecies capripneumoniae ( Mccp ) is the causative agent of contagious caprine pleuropneumonia (CCPP), a devastating disease listed by the World Organisation for Animal Health (WOAH) as a notifiable disease and threatening goat production in Africa and Asia. Although a few commercial inactivated vaccines are available, they do not comply with WOAH standards and there are serious doubts regarding their efficacy. One of the limiting factors to comprehend the molecular pathogenesis of CCPP and develop improved vaccines has been the lack of tools for Mccp genome engineering...
January 2024: Microbiology
https://read.qxmd.com/read/38189440/identification-of-a-system-for-hydroxamate-xenosiderophore-mediated-iron-transport-in-burkholderia-cenocepacia
#16
JOURNAL ARTICLE
Syakira Mohammed Hussein, Aderonke Sofoluwe, Ameya Paleja, Anne Duhme-Klair, Mark S Thomas
One of the mechanisms employed by the opportunistic pathogen Burkholderia cenocepacia to acquire the essential element iron is the production and release of two ferric iron chelating compounds (siderophores), ornibactin and pyochelin. Here we show that B. cenocepacia is also able to take advantage of a range of siderophores produced by other bacteria and fungi ('xenosiderophores') that chelate iron exclusively by means of hydroxamate groups. These include the tris-hydroxamate siderophores ferrioxamine B, ferrichrome, ferricrocin and triacetylfusarinine C, the bis-hydroxamates alcaligin and rhodotorulic acid, and the monohydroxamate siderophore cepabactin...
January 2024: Microbiology
https://read.qxmd.com/read/38180462/genomic-and-functional-insights-into-antibiotic-resistance-genes-flor-and-stra-linked-with-the-sxt-element-of-vibrio-cholerae-non-o1-non-o139
#17
JOURNAL ARTICLE
Mousumi Saha, Agila Kumari Pragasam, Shashi Kumari, Jyoti Verma, Bhabatosh Das, Rupak K Bhadra
The emergence and spread of antibiotic-resistant bacterial pathogens are a critical public health concern across the globe. Mobile genetic elements (MGEs) play an important role in the horizontal acquisition of antimicrobial resistance genes (ARGs) in bacteria. In this study, we have decoded the whole genome sequences of multidrug-resistant Vibrio cholerae clinical isolates carrying the ARG-linked SXT, an integrative and conjugative element, in their large chromosomes. As in others, the SXT element has been found integrated into the 5'-end of the prfC gene (which encodes peptide chain release factor 3 involved in translational regulation) on the large chromosome of V...
January 2024: Microbiology
https://read.qxmd.com/read/38180461/an-assessment-of-the-airborne-longevity-of-group-a-streptococcus
#18
JOURNAL ARTICLE
Henry P Oswin, Evie Blake, Allen E Haddrell, Adam Finn, Shiranee Sriskandan, Jonathan P Reid, Alice Halliday, Anu Goenka
Group A streptococcus (GAS) infections result in more than 500 000 deaths annually. Despite mounting evidence for airborne transmission of GAS, little is known about its stability in aerosol. Measurements of GAS airborne stability were carried out using the Controlled Electrodynamic Levitation and Extraction of Bioaerosols onto a Substrate (CELEBS) instrument. CELEBS measurements with two different isolates of GAS suggest that it is aerostable, with approximately 70 % of bacteria remaining viable after 20 min of levitation at 50 % relative humidity (RH), with lower survival as RH was reduced...
January 2024: Microbiology
https://read.qxmd.com/read/38117289/atomistic-modelling-and-nmr-studies-reveal-that-gallium-can-target-the-ferric-pqs-uptake-system-in-p-aeruginosa-biofilms
#19
JOURNAL ARTICLE
Oliver J Hills, Isaac O K Noble, Alex Heyam, Andrew J Scott, James Smith, Helen F Chappell
Intravenous gallium nitrate therapy is a novel therapeutic strategy deployed to combat chronic Pseudomonas aeruginosa biofilm infections in the lungs of cystic fibrosis (CF) patients by interfering with iron (Fe3+ ) uptake. The therapy is a source of Ga3+ , which competes with Fe3+ for siderophore binding, subsequently disrupting iron metabolism and inhibiting biofilm proliferation in vivo . It was recently demonstrated that the Pseudomonas quinolone signal (PQS) can chelate Fe3+ to assist in bacterial iron uptake...
December 2023: Microbiology
https://read.qxmd.com/read/38116759/interbacterial-competition-mediated-by-the-type-viib-secretion-system
#20
JOURNAL ARTICLE
Eleanor R Boardman, Tracy Palmer, Felicity Alcock
Successful occupancy of a given niche requires the colonising bacteria to interact extensively with the biotic and abiotic environment, including other resident microbes. Bacteria have evolved a range of protein secretion machines for this purpose with eleven such systems identified to date. The type VIIb secretion system (T7SSb) is utilised by Bacillota to secrete a range of protein substrates, including antibacterial toxins targeting closely related strains, and the system as a whole has been implicated in a range of activities such as iron acquisition, intercellular signalling, host colonisation and virulence...
December 2023: Microbiology
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