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https://www.readbyqxmd.com/read/28742082/bacterial-deception-of-mait-cells-in-a-cloud-of-superantigen-and-cytokines
#1
Johan K Sandberg, Anna Norrby-Teglund, Edwin Leeansyah
The bacterium Staphylococcus aureus is an important cause of the life-threatening condition toxic shock syndrome in humans. Bacterial toxins known as superantigens (SAgs) generate this illness by acting as broad activators of a substantial fraction of all T lymphocytes, bypassing the normally highly stringent T-cell receptor antigen specificity to cause a systemic inflammatory cytokine storm in the host. In a new study, Shaler et al. found that immune cells called mucosa-associated invariant T (MAIT) cells make an unexpectedly large contribution to the SAg response in a largely T-cell receptor-independent, cytokine-driven manner...
July 24, 2017: PLoS Biology
https://www.readbyqxmd.com/read/28737000/chemoprofile-and-functional-diversity-of-fungal-and-bacterial-endophytes-and-role-of-ecofactors-a-review
#2
REVIEW
Aiyatullah Shah, Qazi Parvaiz Hassan, Saleem Mushtaq, Aabid Manzoor Shah, Aehtesham Hussain
Endophytes represent a hidden world within plants. Almost all plants that are studied harbor one or more endophytes, which help their host to survive against pathogens and changing adverse environmental conditions. Fungal and bacterial endophytes with distinct ecological niches show important biological activities and ecological functions. Their unique physiological and biochemical characteristics lead to the production of niche specific secondary metabolites that may have pharmacological potential. Identification of specific secondary metabolites in adverse environment can also help us in understanding mechanisms of host tolerance against stress condition such as biological invasions, salt, drought, temperature...
July 24, 2017: Journal of Basic Microbiology
https://www.readbyqxmd.com/read/28736259/molecular-epidemiology-and-antimicrobial-susceptibility-of-clostridium-difficile-isolated-from-the-chinese-people-s-liberation-army-general-hospital-in-china
#3
Rui Wang, Hui Xia Chen, Lin Jian Song, Yue Yun Shen, Yan Ping Luo
Clostridium difficile is a gram-positive, spore-forming obligate anaerobe responsible for antibiotic-associated diarrhea. Its virulence is associated with the production of endotoxins A and B and endospores, which can cause symptoms, such as diarrhea, toxic megacolon and pseudomembranous colitis. Given the increasing elderly population and the well-recognized problem of over-prescribing of broad spectrum antibiotics, it is critical to understand molecular epidemiology and antimicrobial susceptibility in China...
July 20, 2017: International Journal of Infectious Diseases: IJID
https://www.readbyqxmd.com/read/28733486/%C3%AE-toxin-regulates-local-granulocyte-expansion-from-hematopoietic-stem-and-progenitor-cells-in-staphylococcus-aureus-infected-wounds
#4
Patrick C Falahee, Leif S Anderson, Mack B Reynolds, Mauricio Pirir, Bridget E McLaughlin, Carly A Dillen, Ambrose L Cheung, Lloyd S Miller, Scott I Simon
The immune response to Staphylococcus aureus infection in skin involves the recruitment of polymorphonuclear neutrophils (PMNs) from the bone marrow via the circulation and local granulopoiesis from hematopoietic stem and progenitor cells (HSPCs) that also traffic to infected skin wounds. We focus on regulation of PMN number and function and the role of pore-forming α-toxin (AT), a virulence factor that causes host cell lysis and elicits inflammasome-mediated IL-1β secretion in wounds. Infection with wild-type S...
July 21, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
https://www.readbyqxmd.com/read/28733288/bacillomycin-d-produced-by-bacillus-amyloliquefaciens-is-involved-in-the-antagonistic-interaction-with-the-plant-pathogenic-fungus-fusarium-graminearum
#5
Qin Gu, Yang Yang, Qiming Yuan, Guangming Shi, Liming Wu, Zhiying Lou, Rong Huo, Huijun Wu, Rainer Borriss, Xuewen Gao
Fusarium graminearum (teleomorph: Ascomycota, Hypocreales, Gibberella, Gibberella zeae) is a destructive fungal pathogen that threatens the production and quality of wheat and barley worldwide. Controlling this toxin-producing pathogen is a significant challenge. In the present study, the commercially available strain Bacillus amyloliquefaciens (Bacteria, Firmicutes, Bacillales, Bacillus) FZB42 showed strong activity against F. graminearum The lipopeptide, bacillomycin D, produced by FZB42, was proven to contribute to the antifungal activity...
July 21, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28732463/common-and-phylogenetically-widespread-coding-for-peptides-by-bacterial-small-rnas
#6
Robin C Friedman, Stefan Kalkhof, Olivia Doppelt-Azeroual, Stephan A Mueller, Martina Chovancová, Martin von Bergen, Benno Schwikowski
BACKGROUND: While eukaryotic noncoding RNAs have recently received intense scrutiny, it is becoming clear that bacterial transcription is at least as pervasive. Bacterial small RNAs and antisense RNAs (sRNAs) are often assumed to be noncoding, due to their lack of long open reading frames (ORFs). However, there are numerous examples of sRNAs encoding for small proteins, whether or not they also have a regulatory role at the RNA level. METHODS: Here, we apply flexible machine learning techniques based on sequence features and comparative genomics to quantify the prevalence of sRNA ORFs under natural selection to maintain protein-coding function in 14 phylogenetically diverse bacteria...
July 21, 2017: BMC Genomics
https://www.readbyqxmd.com/read/28730326/infectious-diseases-causing-autonomic-dysfunction
#7
REVIEW
Francisco Javier Carod Artal
OBJECTIVES: To review infectious diseases that may cause autonomic dysfunction. METHODS: Review of published papers indexed in medline/embase. RESULTS: Autonomic dysfunction has been reported in retrovirus (human immunodeficiency virus (HIV), human T-lymphotropic virus), herpes viruses, flavivirus, enterovirus 71 and lyssavirus infections. Autonomic dysfunction is relatively common in HIV-infected patients and heart rate variability is reduced even in early stages of infection...
July 20, 2017: Clinical Autonomic Research: Official Journal of the Clinical Autonomic Research Society
https://www.readbyqxmd.com/read/28729858/toxin-antitoxin-systems-in-estuarine-synechococcus-strain-cb0101-and-their-transcriptomic-responses-to-environmental-stressors
#8
David Marsan, Allen Place, Daniel Fucich, Feng Chen
Bacterial toxin-antitoxin (TA) systems are genetic elements composed of a toxin gene and its cognate antitoxin, with the ability to regulate growth. TA systems have not previously been reported in marine Synechococcus or Prochlorococcus. Here we report the finding of seven TA system pairs (Type II) in the estuarine Synechococcus CB0101, and their responses of these TA genes to under different stress conditions, which include; nitrogen and phosphate starvation, phage infection, zinc toxicity, and photo-oxidation...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28727722/an-attenuated-shigella-mutant-lacking-the-rna-binding-protein-hfq-provides-cross-protection-against-shigella-strains-of-broad-serotype
#9
Jiro Mitobe, Ritam Sinha, Soma Mitra, Dhrubajyoti Nag, Noriko Saito, Ken Shimuta, Nobuo Koizumi, Hemanta Koley
Few live attenuated vaccines protect against multiple serotypes of bacterial pathogen because host serotype-specific immune responses are limited to the serotype present in the vaccine strain. Here, immunization with a mutant of Shigella flexneri 2a protected guinea pigs against subsequent infection by S. dysenteriae type 1 and S. sonnei strains. This deletion mutant lacked the RNA-binding protein Hfq leading to increased expression of the type III secretion system via loss of regulation, resulting in attenuation of cell viability through repression of stress response sigma factors...
July 20, 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28726545/the-t-6-a-modification-acts-as-a-positive-determinant-for-the-anticodon-nuclease-prrc-and-is-distinctively-nonessential-in-streptococcus-mutans
#10
Jo Marie Bacusmo, Silvia S Orsini, Jennifer Hu, Michael DeMott, Patrick C Thiaville, Ameer Elfarash, Mellie June Paulines, Diego Rojas-Benítez, Birthe Meineke, Chris Deutsch, Dirk Iwata-Reuyl, Patrick A Limbach, Peter C Dedon, Kelly C Rice, Stewart Shuman, Valérie de Crécy-Lagard
Endoribonuclease toxins (ribotoxins) are produced by bacteria and fungi to respond to stress, eliminate non-self competitor species, or interdict virus infection. PrrC is a bacterial ribotoxin that targets and cleaves tRNA(Lys)UUU in the anticodon loop. In vitro studies suggested that the post-transcriptional modification threonylcarbamoyl adenosine (t(6)A) is required for PrrC activity but this prediction had never been validated in vivo. Here, by using t(6)A-deficient yeast derivatives, it is shown that t(6)A is a positive determinant for PrrC proteins from various bacterial species...
July 20, 2017: RNA Biology
https://www.readbyqxmd.com/read/28724903/co-expression-network-analysis-of-toxin-antitoxin-loci-in-mycobacterium-tuberculosis-reveals-key-modulators-of-cellular-stress
#11
Amita Gupta, Balaji Venkataraman, Madavan Vasudevan, Kiran Gopinath Bankar
Research on toxin-antitoxin loci (TA loci) is gaining impetus due to their ubiquitous presence in bacterial genomes and their observed roles in stress survival, persistence and drug tolerance. The present study investigates the expression profile of all the seventy-nine TA loci found in Mycobacterium tuberculosis. The bacterium was subjected to multiple stress conditions to identify key players of cellular stress response and elucidate a TA-coexpression network. This study provides direct experimental evidence for transcriptional activation of each of the seventy-nine TA loci following mycobacterial exposure to growth-limiting environments clearly establishing TA loci as stress-responsive modules in M...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28724662/the-role-of-antibiotics-in-modulating-virulence-in-staphylococcus-aureus
#12
REVIEW
Elisabeth Hodille, Warren Rose, Binh An Diep, Sylvain Goutelle, Gerard Lina, Oana Dumitrescu
Staphylococcus aureus is often involved in severe infections, in which the effects of bacterial virulence factors have great importance. Antistaphylococcal regimens should take into account the different effects of antibacterial agents on the expression of virulence factors and on the host's immune response. A PubMed literature search was performed to select relevant articles on the effects of antibiotics on staphylococcal toxin production and on the host immune response. Information was sorted according to the methods used for data acquisition (bacterial strains, growth models, and antibiotic concentrations) and the assays used for readout generation...
October 2017: Clinical Microbiology Reviews
https://www.readbyqxmd.com/read/28720729/inhibition-of-inflammasome-dependent-interleukin-1%C3%AE-production-by-streptococcal-nad-glycohydrolase-evidence-for-extracellular-activity
#13
Dóra Hancz, Elsa Westerlund, Benedicte Bastiat-Sempe, Onkar Sharma, Christine Valfridsson, Lena Meyer, John F Love, Maghnus O'Seaghdha, Michael R Wessels, Jenny J Persson
Group A Streptococcus (GAS) is a common human pathogen and the etiologic agent of a large number of diseases ranging from mild, self-limiting infections to invasive life-threatening conditions. Two prominent virulence factors of this bacterium are the genetically and functionally linked pore-forming toxin streptolysin O (SLO) and its cotoxin NAD(+)-glycohydrolase (NADase). Overexpression of these toxins has been linked to increased bacterial virulence and is correlated with invasive GAS disease. NADase can be translocated into host cells by a SLO-dependent mechanism, and cytosolic NADase has been assigned multiple properties such as protection of intracellularly located GAS bacteria and induction of host cell death through energy depletion...
July 18, 2017: MBio
https://www.readbyqxmd.com/read/28718822/a-bacterial-toxin-with-analgesic-properties-hyperpolarization-of-drg-neurons-by-mycolactone
#14
Ok-Ryul Song, Han-Byul Kim, Samuel Jouny, Isabelle Ricard, Alexandre Vandeputte, Nathalie Deboosere, Estelle Marion, Christophe J Queval, Pierre Lesport, Emmanuel Bourinet, Daniel Henrion, Seog Bae Oh, Guillaume Lebon, Guillaume Sandoz, Edouard Yeramian, Laurent Marsollier, Priscille Brodin
Mycolactone, a polyketide molecule produced by Mycobacterium ulcerans, is the etiological agent of Buruli ulcer. This lipid toxin is endowed with pleiotropic effects, presents cytotoxic effects at high doses, and notably plays a pivotal role in host response upon colonization by the bacillus. Most remarkably, mycolactone displays intriguing analgesic capabilities: the toxin suppresses or alleviates the pain of the skin lesions it inflicts. We demonstrated that the analgesic capability of mycolactone was not attributable to nerve damage, but instead resulted from the triggering of a cellular pathway targeting AT₂ receptors (angiotensin II type 2 receptors; AT₂R), and leading to potassium-dependent hyperpolarization...
July 18, 2017: Toxins
https://www.readbyqxmd.com/read/28716396/the-role-of-pilin-protein-of-xenorhabdus-nematophila-against-immune-defense-reactions-of-insects
#15
Reyhaneh Darsouei, Javad Karimi, Gary B Dunphy
Xenorhabdus nematophila is a symbiotic bacterium of the entomopathogenic nematode Steinernema carpocapsae (Weiser). It produces several toxic proteins which interfere with the immune system of insects. The current study shows that purified pilin protein could be a virulence trait of X. nematophila. The fifth instar larvae of Spodoptera exigua (Hübner) was injected with purified pilin. Changes in the cellular defenses in terms of total haemocyte counts and granulocyte percentage and humoral factors including total protease, phospholipase A2, and phenoloxidase activities (humoral defense) as well as the expression of the three main antimicrobial peptides attacin, cecropin, and spodoptericin were measured at specific times...
July 14, 2017: Journal of Insect Physiology
https://www.readbyqxmd.com/read/28715501/diversity-and-distribution-of-nuclease-bacteriocins-in-bacterial-genomes-revealed-using-hidden-markov-models
#16
Connor Sharp, James Bray, Nicholas G Housden, Martin C J Maiden, Colin Kleanthous
Bacteria exploit an arsenal of antimicrobial peptides and proteins to compete with each other. Three main competition systems have been described: type six secretion systems (T6SS); contact dependent inhibition (CDI); and bacteriocins. Unlike T6SS and CDI systems, bacteriocins do not require contact between bacteria but are diffusible toxins released into the environment. Identified almost a century ago, our understanding of bacteriocin distribution and prevalence in bacterial populations remains poor. In the case of protein bacteriocins, this is because of high levels of sequence diversity and difficulties in distinguishing their killing domains from those of other competition systems...
July 17, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28713333/algevir-an-expression-system-for-microalgae-based-on-viral-vectors
#17
Bernardo Bañuelos-Hernández, Elizabeth Monreal-Escalante, Omar González-Ortega, Carlos Angulo, Sergio Rosales-Mendoza
The use of recombinant algae for the production of valuable compounds is opening promising biotechnological applications. However, the development of efficient expression approaches is still needed to expand the exploitation of microalgae in biotechnology. Herein, the concept of using viral expression vectors in microalgae was explored for the first time. An inducible geminiviral vector leading to Rep-mediated replication of the expression cassette allowed the production of antigenic proteins at high levels...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28712711/specificity-and-putative-mode-of-action-of-a-mosquito-larvicidal-toxin-from-the-bacterium-xenorhabdus-innexi
#18
Il-Hwan Kim, Jerald Ensign, Do-Young Kim, Hoe-Yune Jung, Na-Ri Kim, Bo-Hwa Choi, Sun-Min Park, Que Lan, Walter G Goodman
Reduction of mosquito-borne diseases relies, in part, on the use of synthetic pesticides to control pest mosquitoes. This reliance has led to genetic resistance, environmental contamination and the nondiscriminatory elimination of both pest and non-pest species. To expand our options for control, we screened entomopathogenic bacteria for potential larvicidal activity. A lipopeptide from the bacterium, Xenorhabdus innexi, was discovered that displayed potent larvicidal activity. The LC50s of the lipopeptide towards Aedes aegypti, Culex pipiens and Anopheles gambiae larvae were 1...
July 13, 2017: Journal of Invertebrate Pathology
https://www.readbyqxmd.com/read/28711253/the-capacity-of-silage-inoculant-bacteria-to-bind-aflatoxin-b1-in-vitro-and-in-artificially-contaminated-corn-silage
#19
Z X Ma, F X Amaro, J J Romero, O G Pereira, K C Jeong, A T Adesogan
The objectives were to examine the aflatoxin B1 (AFB1)-binding capacity of silage bacteria and factors affecting the responses. Experiments 1 and 2 examined the effects of bacterial strain and population on the AFB1-binding capacity of 10 bacteria. When applied at 10(6) cfu/mL to an in vitro medium, only Lactobacillus plantarum PT5B bound the AFB1 and the binding capacity was low (4%). When applied at 10(9) cfu/mL, all 10 bacteria bound AFB1, but L. plantarum R2014 (Lp) and EQ12, Lactobacillus buchneri R1102 (Lb), and Pediococcus acidilactici R2142 and EQ01 (Pa) had the greatest capacity (23...
July 12, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28711159/-hemolytic-and-uremic-syndrome-and-related-thrombotic-microangiopathies-epidemiology-pathophysiology-and-clinics
#20
C Rafat, P Coppo, F Fakhouri, V Frémeaux-Bacchi, C Loirat, J Zuber, E Rondeau
Thrombotic microangiopathies (TMA) represent an eclectic group of conditions, which share hemolytic anemia and thrombocytopenia as a common defining basis. Remarkable breakthroughs in the physiopathological setting have allowed for a thorough recomposition of the disparate syndromes, which form the constellation of TMA. In this view, clinicians now discriminate thrombocytopenic thrombotic purpura (TTP) defined by a severe deficiency in ADAMTS13, which is rarely associated with a severe renal involvement and the hemolytic and uremic syndrome (HUS) in which renal impairment is the most prominent clinical feature...
July 12, 2017: La Revue de Médecine Interne
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