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Bacteria host pathogen

Guirong Tang, Qiong Li, Shenghui Xing, Ningning Li, Zheng Tang, Liangliang Yu, Junhui Yan, Xuan Li, Li Luo
Agrobacterium tumefaciens infects and causes crown galls in dicot plants by transferring T-DNA from the Ti plasmid to the host plant via a type IV secretion system (T4SS). This process requires appropriate environmental conditions, certain plant secretions and bacterial regulators. In our previous work, a member of the LysR family of transcriptional regulators (LsrB) in Sinorhizobium meliloti was found to modulate its symbiotic interactions with the host plant alfalfa. However, the function of its homologue in A...
March 16, 2018: Molecular Plant-microbe Interactions: MPMI
Piera Valenti, Luigi Rosa, Daniela Capobianco, Maria Stefania Lepanto, Elisa Schiavi, Antimo Cutone, Rosalba Paesano, Paola Mastromarino
The innate defense system of the female mucosal genital tract involves a close and complex interaction among the healthy vaginal microbiota, different cells, and various proteins that protect the host from pathogens. Vaginal lactobacilli and lactoferrin represent two essential actors in the vaginal environment. Lactobacilli represent the dominant bacterial species able to prevent facultative and obligate anaerobes outnumber in vaginal microbiota maintaining healthy microbial homeostasis. Several mechanisms underlie the protection exerted by lactobacilli: competition for nutrients and tissue adherence, reduction of the vaginal pH, modulation of immunity, and production of bioactive compounds...
2018: Frontiers in Immunology
BoYoon Chang, BongSeong Koo, HyeonCheol Lee, Joa Sub Oh, SungYeon Kim
Background: The innate immune system plays a crucial role in the initiation and subsequent direction of adaptive immune responses, as well as in the removal of pathogens that have been targeted by an adaptive immune response. Objective: Morus alba L. was reported to have immunostimulatory properties that might protect against infectious diseases. However, this possibility has not yet been explored. The present study investigated the protective and immune-enhancing ability of M...
2018: Food & Nutrition Research
Riyoko Tamai, Michiyo Kobayashi-Sakamoto, Yusuke Kiyoura
Galectin-1 and galectin-3 are C-type lectin receptors that bind to lipopolysaccharide (LPS) in the cell wall of gram-negative bacteria. In this study, we investigated the effects of galectin-1 and galectin-3 on adhesion to and invasion of the human gingival epithelial cell line Ca9-22 by Porphyromonas gingivalis, a periodontal pathogenic gram-negative bacterium. Recombinant galectin-1, but not galectin-3, enhanced P. gingivalis adhesion and invasion, although both galectins bound similarly to P. gingivalis...
March 15, 2018: Canadian Journal of Microbiology
Valerie F L Yong, Min Min Soh, Tavleen Kaur Jaggi, Micheál Mac Aogáin, Sanjay H Chotirmall
Pseudomonas aeruginosa is a major pathogen responsible for both acute and chronic infection. Known as a colonising pathogen of the cystic fibrosis (CF) lung, it is implicated in other settings such as bronchiectasis. It has the ability to cause acute disseminated or localised infection particularly in the immunocompromised. Human hormones have been highlighted as potential regulators of bacterial virulence through crosstalk between analogous "quorum sensing" (QS) systems present in the bacteria that respond to mammalian hormones...
March 14, 2018: Archivum Immunologiae et Therapiae Experimentalis
Kui Huang, Hui Xia, Ying Wu, Jingyang Chen, Guangyu Cui, Fusheng Li, Yongzhi Chen, Nan Wu
Diverse antibiotic resistance genes (ARGs) present in sewage sludge are difficult to be eliminated using conventional sludge treatment processes. To date, little remains known on the fate of the ARGs during vermicomposting of sludge. This study aimed to investigate the effect of earthworms on the fate of tetracycline and fluoroquinolone resistance genes, and integrons during vermicomposting of sewage sludge through contrasting two systems of sludge stabilization with and without earthworms. Compared to the control without earthworms, vermicomposting significantly (p < 0...
March 7, 2018: Bioresource Technology
Winnie-Pui-Pui Liew, Sabran Mohd-Redzwan
The secondary metabolites produced by fungi known as mycotoxins, are capable of causing mycotoxicosis (diseases and death) in human and animals. Contamination of feedstuffs as well as food commodities by fungi occurs frequently in a natural manner and is accompanied by the presence of mycotoxins. The occurrence of mycotoxins' contamination is further stimulated by the on-going global warming as reflected in some findings. This review comprehensively discussed the role of mycotoxins (trichothecenes, zearalenone, fumonisins, ochratoxins, and aflatoxins) toward gut health and gut microbiota...
2018: Frontiers in Cellular and Infection Microbiology
Sonja Oehmcke-Hecht, Juliane Köhler
The name human contact system is related to its mode of action, as "contact" with artificial negatively charged surfaces triggers its activation. Today, it is generally believed that the contact system is an inflammatory response mechanism not only against artificial material but also against misfolded proteins and foreign organisms. Upon activation, the contact system is involved in at least two distinct (patho)physiologic processes: i . the trigger of the intrinsic coagulation via factor XI and ii ...
2018: Frontiers in Immunology
Santosh K Ghosh, Zhimin Feng, Hisashi Fujioka, Renate Lux, Thomas S McCormick, Aaron Weinberg
Human beta defensins (hBDs) are small cationic peptides, expressed in mucosal epithelia and important agents of innate immunity, act as antimicrobial and chemotactic agents at mucosal barriers. In this perspective, we present evidence supporting a novel strategy by which the oral bacterium Fusobacterium nucleatum induces hBDs and other antimicrobial peptides (AMPs) in normal human oral epithelial cells (HOECs) and thereby protects them from other microbial pathogens. The findings stress (1) the physiological importance of hBDs, (2) that this strategy may be a mechanism that contributes to homeostasis and health in body sites constantly challenged with bacteria and (3) that novel properties identified in commensal bacteria could, one day, be harnessed as new probiotic strategies to combat colonization of opportunistic pathogens...
2018: Frontiers in Microbiology
Xiang Zhang, Adil Mardinoglu, Leo A B Joosten, Jan A Kuivenhoven, Yang Li, Mihai G Netea, Albert K Groen
Immunity and cellular metabolism are tightly interconnected but it is not clear whether different pathogens elicit specific metabolic responses. To address this issue, we studied differential metabolic regulation in peripheral blood mononuclear cells (PBMCs) of healthy volunteers challenged by Candida albicans, Borrelia burgdorferi , lipopolysaccharide, and Mycobacterium tuberculosis in vitro . By integrating gene expression data of stimulated PBMCs of healthy individuals with the KEGG pathways, we identified both common and pathogen-specific regulated pathways depending on the time of incubation...
2018: Frontiers in Physiology
Amy N Jacobson, Biswa P Choudhury, Michael A Fischbach
Lipopolysaccharide (LPS), a cell-associated glycolipid that makes up the outer leaflet of the outer membrane of Gram-negative bacteria, is a canonical mediator of microbe-host interactions. The most prevalent Gram-negative gut bacterial taxon, Bacteroides , makes up around 50% of the cells in a typical Western gut; these cells harbor ~300 mg of LPS, making it one of the highest-abundance molecules in the intestine. As a starting point for understanding the biological function of Bacteroides LPS, we have identified genes in Bacteroides thetaiotaomicron VPI 5482 involved in the biosynthesis of its lipid A core and glycan, generated mutants that elaborate altered forms of LPS, and used matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry to interrogate the molecular features of these variants...
March 13, 2018: MBio
Karissa L Cross, Payal Chirania, Weili Xiong, Clifford J Beall, James G Elkins, Richard J Giannone, Ann L Griffen, Adam M Guss, Robert L Hettich, Snehal S Joshi, Elaine M Mokrzan, Roman K Martin, Igor B Zhulin, Eugene J Leys, Mircea Podar
The human oral microbiota encompasses representatives of many bacterial lineages that have not yet been cultured. Here we describe the isolation and characterization of previously uncultured Desulfobulbus oralis , the first human-associated representative of its genus. As mammalian-associated microbes rarely have free-living close relatives, D. oralis provides opportunities to study how bacteria adapt and evolve within a host. This sulfate-reducing deltaproteobacterium has adapted to the human oral subgingival niche by curtailing its physiological repertoire, losing some biosynthetic abilities and metabolic independence, and by dramatically reducing environmental sensing and signaling capabilities...
March 13, 2018: MBio
Claudia C Paredes-Amaya, Gilberto Valdés-García, Víctor R Juárez-González, Enrique Rudiño-Piñera, Víctor H Bustamante
HilD is an AraC-like transcriptional regulator that plays a central role in Salmonella virulence. HilD controls the expression of the genes within the Salmonella pathogenicity island 1 (SPI-1) and of several genes located outside SPI-1, which are mainly required for Salmonella invasion of host cells. The expression, amount and activity of HilD are tightly controlled by the activities of several factors. The HilE protein represses the expression of the SPI-1 genes through its interaction with HilD; however, the mechanism by which HilE affects HilD is unknown...
March 13, 2018: Journal of Biological Chemistry
Daniel J Becker, Gábor Á Czirják, Dmitriy V Volokhov, Alexandra B Bentz, Jorge E Carrera, Melinda S Camus, Kristen J Navara, Vladimir E Chizhikov, M Brock Fenton, Nancy B Simmons, Sergio E Recuenco, Amy T Gilbert, Sonia Altizer, Daniel G Streicker
Human activities create novel food resources that can alter wildlife-pathogen interactions. If resources amplify or dampen, pathogen transmission probably depends on both host ecology and pathogen biology, but studies that measure responses to provisioning across both scales are rare. We tested these relationships with a 4-year study of 369 common vampire bats across 10 sites in Peru and Belize that differ in the abundance of livestock, an important anthropogenic food source. We quantified innate and adaptive immunity from bats and assessed infection with two common bacteria...
May 5, 2018: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Christopher J Anderson, John Satkovich, Volkan K Köseoğlu, Hervé Agaisse, Melissa M Kendall
Ethanolamine is a ubiquitous and essential molecule within a host. Significantly, bacterial pathogens exploit ethanolamine during infection to promote growth and regulate virulence. The ethanolamine permease EutH is dispensable for growth in vitro under standard conditions, whereas EutH is required for ethanolamine utilization at low pH. These findings suggested a model in which EutH facilitates diffusion of ethanolamine into the bacterial cell in acidic environments. To date, the ecological significance of this model has not been thoroughly investigated, and the importance of EutH to bacterial growth under physiologically relevant conditions is not known...
March 12, 2018: Infection and Immunity
Roberta J Melander, Daniel V Zurawski, Christian Melander
While broad spectrum antibiotics play an invaluable role in the treatment of bacterial infections, there are some drawbacks to their use, namely selection for and spread of resistance across multiple bacterial species, and the detrimental effect they can have upon the host microbiome. If the causitive agent of the infection is known, the use of narrow-spectrum antibacterial agents has the potential to mitigate some of these issues. This review outlines the advantages and challenges of narrow-spectrum antibacterial agents, discusses the progress that has been made toward developing diagnostics to enable their use, and describes some of the narrow-spectrum antibacterial agents currently being investigated against some of the most clinically important bacteria including Clostridium difficile, Mycobacterium tuberculosis and several ESKAPE pathogens...
2018: MedChemComm
Carmen Gómez-Lama Cabanás, Garikoitz Legarda, David Ruano-Rosa, Paloma Pizarro-Tobías, Antonio Valverde-Corredor, José L Niqui, Juan C Triviño, Amalia Roca, Jesús Mercado-Blanco
The use of biological control agents (BCA), alone or in combination with other management measures, has gained attention over the past decades, driven by the need to seek for sustainable and eco-friendly alternatives to confront plant pathogens. The rhizosphere of olive ( Olea europaea L.) plants is a source of bacteria with potential as biocontrol tools against Verticillium wilt of olive (VWO) caused by Verticillium dahliae Kleb. A collection of bacterial isolates from healthy nursery-produced olive (cultivar Picual, susceptible to VWO) plants was generated based on morphological, biochemical and metabolic characteristics, chemical sensitivities, and on their in vitro antagonistic activity against several olive pathogens...
2018: Frontiers in Microbiology
Yafei Duan, Yun Wang, Jiasong Zhang, Qingsong Liu, Xian Ding
The shrimp intestine barrier serves as the first line of the host defense against pathogen infection. Lipopolysaccharide (LPS) is the cell wall component of gram-negative bacteria, which known as endotoxin and induce the intestine inflammation. In this study, the acute toxicity effects of LPS injection on the morphology, digestive enzymes and immunological responses of intestine from Litopenaeus vannamei was investigated. HE stain showed that LPS injection damaged the intestine connective and epithelium tissue...
March 8, 2018: Journal of Invertebrate Pathology
Lingxiao Gong, Wenyan Cao, Jie Gao, Jing Wang, Huijuan Zhang, Baoguo Sun, Meng Yin
The gut microbiota has recently become a new route for research at the intersection of diet and human health. The aim of this study was to investigate whether whole Tibetan hull-less barley (WHB) and refined Tibetan hull-less barley (RHB) caused differentiation of the fecal microbiota in vitro. The microbiota-accessible ingredients in the 2 barley samples were studied using an in vitro enzymatic digestion procedure. After in vitro digestion, insoluble dietary fiber, phenolic compounds, proteins, and β-glucans were 93...
March 10, 2018: Journal of Food Science
Rafael S Aquino, Yvonne Hui-Fang Teng, Pyong Woo Park
Syndecan-1 (Sdc1) is a major cell surface heparan sulfate (HS) proteoglycan of epithelial cells, a cell type targeted by many bacterial pathogens early in their pathogenesis. Loss of Sdc1 in mice is a gain-of-function mutation that significantly decreases the susceptibility to several bacterial infections, suggesting that subversion of Sdc1 is an important virulence strategy. HS glycosaminoglycan (GAG) chains of cell surface Sdc1 promote bacterial pathogenesis by facilitating the attachment of bacteria to host cells...
March 9, 2018: Biochemical Society Transactions
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