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Bacterial pathogenesis

Shachi Joglekar, Mohamed Suliman, Michael Bartsch, Vivek Halder, Jens Maintz, Jaqueline Bautor, Jürgen Zeier, Jane E Parker, Erich Kombrink
In a chemical screen we identified thaxtomin A (TXA), a phytotoxin from plant pathogenic Streptomyces scabies, as a selective and potent activator of Flavin-dependent monooxygenase1 (FMO1) expression in Arabidopsis (Arabidopsis thaliana). TXA induction of FMO1 was unrelated to the production of reactive oxygen species (ROS), plant cell death or its known inhibition of cellulose synthesis. TXA-stimulated FMO1 expression was strictly dependent on Enhanced disease susceptibility1 (EDS1) and Phytoalexin deficient4 (PAD4) but independent of salicylic acid (SA) synthesis via Isochorismate synthase1 (ICS1)...
June 21, 2018: Plant & Cell Physiology
Stefania Senger, Laura Ingano, Rachel Freire, Antony Anselmo, Weishu Zhu, Ruslan Sadreyev, William Allan Walker, Alessio Fasano
Background & Aims: Untreated necrotizing enterocolitis (NEC) can lead to massive inflammation resulting in intestinal necrosis with a high mortality rate in preterm infants. Limited access to human samples and relevant experimental models have hampered progress in NEC pathogenesis. Earlier evidence has suggested that bacterial colonization of an immature and developing intestine can lead to an abnormally high inflammatory response to bacterial bioproducts. The aim of our study was to use human fetal organoids to gain insights into NEC pathogenesis...
2018: Cellular and Molecular Gastroenterology and Hepatology
Larissa O C P Rodrigues, Rodrigo S F Graça, Leticia A M Carneiro
Activation of an appropriate innate immune response to bacterial infection is critical to limit microbial spread and generate cytokines and chemokines to instruct appropriate adaptive immune responses. Recognition of bacteria or bacterial products by pattern recognition molecules is crucial to initiate this response. However, it is increasingly clear that the context in which this recognition occurs can dictate the quality of the response and determine the outcome of an infection. The cross talk established between host and pathogen results in profound alterations on cellular homeostasis triggering specific cellular stress responses...
2018: Frontiers in Immunology
Leticia Rojas, Samanta Melgar-Rodríguez, Jaime Díaz-Zúñiga, Carla Alvarez, Gustavo Monasterio, Carolina Rojas, Paola Carvajal, Rolando Vernal
OBJECTIVE: In Aggregatibacter actinomycetemcomitans, different serotypes have been described based on LPS antigenicity. Mixed infection with the different A. actinomycetemcomitans serotypes is frequent in periodontitis patients; accordingly, the role of this bacterial species in the pathogenesis of periodontitis may differ depending whether patients or periodontal lesions harbour one or more of the A. actinomycetemcomitans serotypes. We hypothesized that different combinations of these serotypes could be associated with distinct host responses and hence different inflammatory patterns...
June 12, 2018: Archives of Oral Biology
Xiao-Yan Yuan, Ying Wang, Ming-Yi Wang
Helicobacter pylori (H. pylori) has an essential role in the pathogenesis of gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue lymphoma and gastric cancer. The severity of the host inflammatory responses against the bacteria have been straightly associated with a special bacterial virulence factor, the cag pathogenicity island, which is a type IV secretion system (T4SS) to deliver CagA into the host cells. Besides cag-T4SS, the chromosomes of H. pylori can encode another three T4SSs, including comB, tfs3 and tfs4...
June 21, 2018: Future Microbiology
Yu-Jin Jeong, Sung-Kyun Park, Sung-Jin Yoon, Young Jun Park, Moo-Seung Lee
Shiga toxins (Stxs) are the main virulence factors expressed by the pathogenic Stx-producing bacteria, namely, Shigella dysenteriae serotype 1 and certain Escherichia coli strains. These bacteria cause widespread outbreaks of bloody diarrhea (hemorrhagic colitis) that in severe cases can progress to life-threatening systemic complications, including hemolytic uremic syndrome (HUS)characterized by the acute onset of microangiopathic hemolytic anemia and kidney dysfunction.Shiga toxicosis has a distinct pathogenesis and animal models of Stxs-associated HUS have allowed us to investigate this...
May 11, 2018: Journal of Microbiology and Biotechnology
Emad Kordbacheh, Shahram Nazarian, Davoud Sadeghi, Abbas Hajizadeh
Objectives: Enterotoxigenic Escherichia coli (ETEC) is known as the most common bacterial causes of diarrheal diseases related to morbidity and mortality. Heat-labile enterotoxin (LT) is a part of major virulence factors in ETEC pathogenesis. Antigen entrapment into nanoparticles (NPs) can protect them and enhance their immunogenicity. Materials and Methods: In the present study, recombinant LTB protein was expressed in E. coli BL21 (DE3) and purified by an Ni-NTA agarose column...
May 2018: Iranian Journal of Basic Medical Sciences
P J Tozer, P Lung, A J Lobo, S Sebastian, S R Brown, A L Hart, N Fearnhead
BACKGROUND: Evidence from groups who have studied fistula aetiology and extrapolation from interventional studies supports a multifactorial hypothesis of Crohn's perianal fistula, with several pathophysiological elements that may contribute to fistula formation, persistence and resistance to treatment. AIM: An evidence synthesis of current understanding of pathophysiological factors underlying Crohn's perianal fistula is presented, exploring the fundamental reasons why some treatments succeed and others fail, as a means of focussing clinical knowledge on improving treatment of Crohn's perianal fistula...
June 19, 2018: Alimentary Pharmacology & Therapeutics
Jai W Mehat, Simon F Park, Arnoud H M van Vliet, Roberto M La Ragione
Campylobacter jejuni is recognized as an important causative agent of bacterial gastroenteritis in the developed world. Despite the identification of several factors contributing to infection, characterization of the virulence strategies employed by C. jejuni remains a significant challenge. Bacterial autotransporter proteins are a major class of secretory proteins in Gram-negative bacteria and notably many autotransporter proteins contribute to bacterial virulence. The aim of this study was to characterise the C...
June 18, 2018: Applied and Environmental Microbiology
Stephanus T Malherbe, Léanie Kleynhans, Gerhard Walzl
The development of an improved vaccine to stimulate an effective response against Mycobacterium tuberculosis (MTB) infection and disease will be a major breakthrough in the fight against TB. A lack of tools to adequately track the progression or resolution of events in TB pathogenesis that occur at bacterial loads below the threshold for culture in human samples seriously hampers vaccine development and evaluation. In this review we discuss recent studies that use new imaging applications, modalities and analysis techniques to provide insight into the dynamic processes of MTB infection and disease that are challenging to monitor...
June 15, 2018: Seminars in Immunology
Marlies Elderman, Floor Hugenholtz, Clara Belzer, Mark Boekschoten, Adriaan van Beek, Bart de Haan, Huub Savelkoul, Paul de Vos, Marijke Faas
BACKGROUND: A dysbiosis in the intestinal microbiome plays a role in the pathogenesis of several immunological diseases. These diseases often show a sex bias, suggesting sex differences in immune responses and in the intestinal microbiome. We hypothesized that sex differences in immune responses are associated with sex differences in microbiota composition. METHODS: Fecal microbiota composition (MITchip), mRNA expression in intestinal tissue (microarray), and immune cell populations in mesenteric lymph nodes (MLNs) were studied in male and female mice of two mouse strains (C57B1/6OlaHsd and Balb/cOlaHsd)...
June 18, 2018: Biology of Sex Differences
Annelies Michiels, Ioannis Arsenakis, Anneleen Matthijs, Filip Boyen, Geert Haesaert, Kris Audenaert, Mia Eeckhout, Siska Croubels, Freddy Haesebrouck, Dominiek Maes
BACKGROUND: The mycotoxin deoxynivalenol (DON) is highly prevalent in cereals in moderate climates and therefore pigs are often exposed to a DON-contaminated diet. Pigs are highly susceptible to DON and intake of DON-contaminated feed may lead to an altered immune response and may influence the pathogenesis of specific bacterial diseases. Therefore, the maximum guidance level in feed is lowest in this species and has been set at 900 μg/kg feed by the European Commission. This study aimed to determine the effect of in-feed administration of a moderately high DON concentration (1514 μg/kg) on the severity of an experimental Mycoplasma hyopneumoniae (M...
June 18, 2018: BMC Veterinary Research
George Tetz, Victor Tetz
The pathogenesis of numerous human multifaceted devastating diseases, including a variety of neurodegenerative and autoimmune diseases, is associated with alterations in the gut microbiota; however, the underlying mechanisms are not completely understood. Our recent human metagenome and phagobiota proteome analyses and studies in relevant animal models suggested that bacterial viruses might be implicated in the progression and maintenance of at least some pathologies, including those associated with protein misfolding...
June 16, 2018: Microorganisms
Thomas W Carion, Matthew Greenwood, Abdul Shukkur Ebrahim, Andrew Jerome, Susmit Suvas, Karsten Gronert, Elizabeth A Berger
Although autacoids primarily derived from the cyclooxygenase-2 and 5-lipoxygenase (LOX) pathways are essential mediators of inflammation, endogenous specialized proresolving mediators (SPMs) act as robust agonists of resolution. SPM biosynthesis is initiated by the conversion of arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid primarily via the 12/15-LOX pathway. Although 12/15-LOX activity is prominent in the cornea, the role of SPM pathway activation during infection remains largely unknown and is the focus of the current study...
April 13, 2018: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
Tristan P Lindberg, Melissa J Caimano, James I Hagadorn, Erin M Bennett, Kendra Maas, Elizabeth A Brownell, Adam P Matson
OBJECTIVES: To define gut microbial patterns in preterm infants with and without necrotizing enterocolitis (NEC) and to characterize clinical factors related to the composition of the preterm intestinal microbiome. METHODS: Fecal samples were collected at 1-week intervals from infants with gestational ages < 30 weeks at a single level IV neonatal intensive care unit. Using 16S rRNA gene sequencing, the composition and diversity of microbiota were determined in samples collected from five NEC infants and five matched controls...
June 18, 2018: Journal of Maternal-fetal & Neonatal Medicine
Qinying Wang, Haihong Chen, Yang Yang, Bo Wang
OBJECTIVE: Adherence of pathogen to nasal mucosa and colonization is the first step of bacterial biofilm(BBF) formation in patients with chronic rhinosinusitis (CRS).Terminal sialic acids presenting on cell surface are potential targets for bacterial binding, thus may partly contribute to the pathogenesis of CRS. However, little has been published in this respect, the purpose of our study aimed to investigate the expression of sialic acids on the nasal mucosa in CRS patients and its possible effect on BBF formation...
June 12, 2018: Microbial Pathogenesis
Zhe Xun, Qian Zhang, Tao Xu, Ning Chen, Feng Chen
Inflammatory bowel diseases (IBDs) are chronic, idiopathic, relapsing disorders of unclear etiology affecting millions of people worldwide. Aberrant interactions between the human microbiota and immune system in genetically susceptible populations underlie IBD pathogenesis. Despite extensive studies examining the involvement of the gut microbiota in IBD using culture-independent techniques, information is lacking regarding other human microbiome components relevant to IBD. Since accumulated knowledge has underscored the role of the oral microbiota in various systemic diseases, we hypothesized that dissonant oral microbial structure, composition, and function, and different community ecotypes are associated with IBD; and we explored potentially available oral indicators for predicting diseases...
2018: Frontiers in Microbiology
Miki Yamada, Naoki Takahashi, Yumi Matsuda, Keisuke Sato, Mai Yokoji, Benso Sulijaya, Tomoki Maekawa, Tatsuo Ushiki, Yoshikazu Mikami, Manabu Hayatsu, Yusuke Mizutani, Shigenobu Kishino, Jun Ogawa, Makoto Arita, Koichi Tabeta, Takeyasu Maeda, Kazuhisa Yamazaki
Several studies have demonstrated the remarkable properties of microbiota and their metabolites in the pathogenesis of several inflammatory diseases. 10-Hydroxy-cis-12-octadecenoic acid (HYA), a bioactive metabolite generated by probiotic microorganisms during the process of fatty acid metabolism, has been studied for its protective effects against epithelial barrier impairment in the intestines. Herein, we examined the effect of HYA on gingival epithelial barrier function and its possible application for the prevention and treatment of periodontal disease...
June 13, 2018: Scientific Reports
Catherine J Andersen
Cellular cholesterol metabolism, lipid raft formation, and lipoprotein interactions contribute to the regulation of immune-mediated inflammation and response to pathogens. Lipid pathways have been implicated in the pathogenesis of bacterial and viral infections, whereas altered lipid metabolism may contribute to immune dysfunction in autoimmune diseases, such as systemic lupus erythematosus, multiple sclerosis, and rheumatoid arthritis. Interestingly, dietary cholesterol may exert protective or detrimental effects on risk, progression, and treatment of different infectious and autoimmune diseases, although current findings suggest that these effects are variable across populations and different diseases...
June 13, 2018: Nutrients
Chukwunonso Onyilagha, Shiby Kuriakose, Nnamdi Ikeogu, Ping Jia, Jude Uzonna
Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of bone marrow-derived myeloid cells that have immune-suppressive activities. These cells have been reported to suppress T cell immunity against tumors as well as in some parasitic and bacterial infections. However, their role during Trypanosoma congolense infection has not been studied. Given that immunosuppression is a hallmark of African trypanosomiasis, we investigated the role of MDSCs in immunity to T. congolense infection. We found increased numbers of MDSCs in the spleen and liver of infected mice, which correlated with increased parasitemia...
June 13, 2018: Journal of Immunology: Official Journal of the American Association of Immunologists
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