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Host Pathogen Dynamics

Jose Luis Del Pozo
Biofilm formation represents a protected mode of growth that renders bacterial cells less susceptible to antimicrobials and to killing by host immune effector mechanisms and so enables the pathogens to survive in hostile environments and also to disperse and colonize new niches. Biofilm disease includes device-related infections, chronic infections in the absence of a foreign body, and even malfunction of medical devices. Areas covered: This review puts forward a new medical entity that represents a major public health issue, which we have named "biofilm-related disease"...
December 13, 2017: Expert Review of Anti-infective Therapy
Roman Zug, Peter Hammerstein
Maternally inherited symbionts such as Wolbachia have long been seen mainly as reproductive parasites, with deleterious effects on host fitness. It is becoming clear, however, that, frequently, these symbionts also have beneficial effects on host fitness, either along with reproductive parasitism or not. Using the examples of cytoplasmic incompatibility (CI) and male-killing (MK), we here analyze the effect of direct fitness benefits on the evolution of reproductive parasites. By means of a simple theoretical framework, we synthesize and extend earlier modeling approaches for CI and MK, which usually ignore fitness benefits...
December 13, 2017: Heredity
Eirini Moysi, Kartika Padhan, Giulia Fabozzi, Constantinos Petrovas
PURPOSE OF REVIEW: To describe recent findings on the effect of HIV/SIV infection on lymph node viral and T-cell dynamics using imaging-based methodologies. RECENT FINDINGS: Chronic infection, particularly HIV/SIV, alters dramatically the microenvironment, immune cell frequency, distribution, function and tissue organization of secondary lymphoid tissues. These changes are not always reversible. Over the past few years, the implementation of advanced imaging protocols on human lymph node biopsies as well as on longitudinal lymphoid tissues samples from nonhuman primates (NHP) have provided a wealth of information on how local immune responses evolve over time in response to a persisting retroviral pathogen...
December 8, 2017: Current Opinion in HIV and AIDS
Lauren M Segal, Richard A Wilson
Fungal interactions with plants can involve specific morphogenetic developments to access host cells, the suppression of plant defenses, and the establishment of a feeding lifestyle that nourishes the colonizer often-but not always-at the expense of the host. Reactive oxygen species (ROS) metabolism is central to the infection process, and the stage-specific production and/ or neutralization of ROS is critical to the success of the colonization process. ROS metabolism during infection is dynamic-sometimes seemingly contradictory-and involves endogenous and exogenous sources...
December 7, 2017: Fungal Genetics and Biology: FG & B
Wei Shi, Zhi-Yong Wei, Hany M Elsheikha, Fu-Kai Zhang, Zhao-An Sheng, Ke-Jing Lu, Dong-Ying Wang, Wei-Yi Huang, Xing-Quan Zhu
BACKGROUND: Determining the mechanisms involved in the immune-pathogenesis of the tropical liver fluke, Fasciola gigantica, is crucial to the development of any effective therapeutic intervention. Here, we examined the differential gene expression of cytokines and transcription factors in the liver of F. gigantica-infected buffaloes, over the course of infection. METHODS: Water buffaloes (swamp type) were infected orally with 500 F. gigantica encysted metacercariae...
December 8, 2017: Parasites & Vectors
Alice Labaronne, Sigrid Milles, Amélie Donchet, Malene Ringkjøbing Jensen, Martin Blackledge, Jean-Marie Bourhis, Rob W H Ruigrok, Thibaut Crépin
Influenza viruses are negative strand RNA viruses that replicate in the nucleus of the cell. The viral nucleoprotein (NP) is the major component of the viral ribonucleoprotein. In this paper we show that the NP of influenza B has a long N-terminal tail of 70 residues with intrinsic flexibility. This tail contains the Nuclear Location Signal (NLS). The nuclear trafficking of the viral components mobilizes cellular import factors at different stages, making these host-pathogen interactions promising targets for new therapeutics...
December 7, 2017: Scientific Reports
Sayoko Oiki, Reiko Kamochi, Bunzo Mikami, Kousaku Murata, Wataru Hashimoto
Glycosaminoglycans (GAGs), constituted by repeating uronate and amino sugar units, are major components of mammalian extracellular matrices. Some indigenous and pathogenic bacteria target GAGs for colonization to and/or infection of host mammalian cells. In Gram-negative pathogenic Streptobacillus moniliformis, the solute-binding protein (Smon0123)-dependent ATP-binding cassette (ABC) transporter incorporates unsaturated GAG disaccharides into the cytoplasm after depolymerization by polysaccharide lyase. Smon0123, composed of N and C domains, adopts either a substrate-free open or a substrate-bound closed form by approaching two domains at 47° in comparison with the open form...
December 5, 2017: Scientific Reports
Servane Le Guillouzer, Marie-Christine Groleau, Eric Déziel
The genome of the bacterium Burkholderia thailandensis encodes three complete LuxI/LuxR-type quorum sensing (QS) systems: BtaI1/BtaR1 (QS-1), BtaI2/BtaR2 (QS-2), and BtaI3/BtaR3 (QS-3). The LuxR-type transcriptional regulators BtaR1, BtaR2, and BtaR3 modulate the expression of target genes in association with various N-acyl-l-homoserine lactones (AHLs) as signaling molecules produced by the LuxI-type synthases BtaI1, BtaI2, and BtaI3. We have systematically dissected the complex QS circuitry of B. thailandensis strain E264...
December 5, 2017: MBio
Pauline Vitry, Claire Valotteau, Cécile Feuillie, Simon Bernard, David Alsteens, Joan A Geoghegan, Yves F Dufrêne
Bacterial pathogens that colonize host surfaces are subjected to physical stresses such as fluid flow and cell surface contacts. How bacteria respond to such mechanical cues is an important yet poorly understood issue. Staphylococcus aureus uses a repertoire of surface proteins to resist shear stress during the colonization of host tissues, but whether their adhesive functions can be modulated by physical forces is not known. Here, we show that the interaction of S. aureus clumping factor B (ClfB) with the squamous epithelial cell envelope protein loricrin is enhanced by mechanical force...
December 5, 2017: MBio
Abraham J Waldman, Emily P Balskus
Despite significant advances in treating infectious diseases worldwide, morbidity and mortality associated with these pathogens remains extraordinarily high and represents a critical scientific and global health challenge. Current strategies to combat these infectious agents include a combination of vaccines, small molecule drugs, increased hygiene standards, and disease-specific interventions. While these approaches have helped to drastically reduce the incidence and number of deaths associated with infection, continued investment in current strategies and the development of novel therapeutic approaches will be required to address these global health threats...
December 5, 2017: ACS Infectious Diseases
Ayan Roy, Arnab Sen, Sourav Chakrobarty, Indrani Sarkar
Mycobacterium is an interesting genus which not only includes intimidating pathogens, associated with severe devastations globally, but also comprises of non-pathogenic eco-friendly members that detoxify environmental pollutants. Secretory proteins of the mycobacterial communities are essential components which are firmly believed to facilitate proper cross-talk and apt communication with host cellular surroundings and environmental niche. Secretory elements also play vital roles in mycobacterial pathogenesis...
December 4, 2017: World Journal of Microbiology & Biotechnology
Kendal G Cooper, Audrey Chong, Tregei Starr, Ciaran E Finn, Olivia Steele-Mortimer
Here we describe the use of synthetic genetic elements to improve the predictability and tunability of episomal protein production in Salmonella. We used a multi-pronged approach, in which a series of variable-strength synthetic promoters were combined with a synthetic transcriptional terminator, and plasmid copy number variation. This yielded a series of plasmids that drive uniform production of fluorescent and endogenous proteins, over a wide dynamic range. We describe several examples where this system is used to fine-tune constitutive expression in Salmonella, providing an efficient means to titrate out toxic effects of protein production...
2017: Frontiers in Cellular and Infection Microbiology
Jesse D Pyle, K-B G Scholthof
Panicum mosaic virus (PMV) is a helper RNA virus for satellite RNAs (satRNAs) and a satellite virus (SPMV). Here, we describe modifications that occur at the 3'-end of a satRNA of PMV, satS. Co-infections of PMV+satS result in attenuation of the disease symptoms induced by PMV alone in Brachypodium distachyon and proso millet. The 375 nt satS acquires ~100-200 nts from the 3'-end of PMV during infection and is associated with decreased abundance of the PMV RNA and capsid protein in millet. PMV-satS chimera RNAs were isolated from native infections of St...
November 29, 2017: Virology
Srayan Ghosh, Poonam Kanwar, Gopaljee Jha
Sheath blight disease is one of the predominant diseases of rice and it is caused by the necrotrophic fungal pathogen Rhizoctonia solani. The mechanistic insight about its widespread success as a broad host range pathogen is limited. In this study, we endeavor to identify pathogenicity determinants of R. solani during infection process in rice. Through RNAseq analysis, we identified a total of 65 and 232 R. solani (strain BRS1) genes to be commonly upregulated in three different rice genotypes (PB1, Tetep, and TP309) at establishment and necrotrophic phase, respectively...
December 1, 2017: Current Genetics
Lianguo Chen, Yongyong Guo, Chenyan Hu, Paul K S Lam, James C W Lam, Bingsheng Zhou
Gut microbiota is of critical relevance to host health. However, toxicological understanding of environmental pollutants on gut microbiota is limited, not to mention their combined effects. In the present study, adult zebrafish (Danio rerio) were exposed to titanium dioxide nanoparticles (nano-TiO2; 100 μg/L), bisphenol A (BPA; 0, 2, and 20 μg/L) or their binary mixtures for three months. Sequencing of 16S rRNA amplicons found that nano-TiO2 and BPA coexposure shifted the intestinal microbial community, interacting in an antagonistic manner when the BPA concentration was low but in a synergistic manner at a higher BPA concentration...
November 27, 2017: Environmental Pollution
Alice M Laughton, Cian O O'Connor, Robert J Knell
Environmental temperature has important effects on the physiology and life history of ectothermic animals, including investment in the immune system and the infectious capacity of pathogens. Numerous studies have examined individual components of these complex systems, but little is known about how they integrate when animals are exposed to different temperatures. Here, we use the Indian meal moth (Plodia interpunctella) to understand how immune investment and disease resistance react and potentially trade-off with other life-history traits...
November 2017: Ecology and Evolution
Michael Habig, Jakob Quade, Eva Holtgrewe Stukenbrock
The fungal wheat pathogen Zymoseptoria tritici possesses a large complement of accessory chromosomes showing presence/absence polymorphism among isolates. These chromosomes encode hundreds of genes; however, their functional role and why the chromosomes have been maintained over long evolutionary times are so far not known. In this study, we addressed the functional relevance of eight accessory chromosomes in reference isolate IPO323. We induced chromosome losses by inhibiting the β-tubulin assembly during mitosis using carbendazim and generated several independent isogenic strains, each lacking one of the accessory chromosomes...
November 28, 2017: MBio
Florence Abdallah, Lily Mijouin, Chantal Pichon
The skin is an essential organ to the human body protecting it from external aggressions and pathogens. Over the years, the skin was proven to have a crucial immunological role, not only being a passive protective barrier but a network of effector cells and molecular mediators that constitute a highly sophisticated compound known as the "skin immune system" (SIS). Studies of skin immune sentinels provided essential insights of a complex and dynamic immunity, which was achieved through interaction between the external and internal cutaneous compartments...
2017: Mediators of Inflammation
Xiuling Yang, Bi Wang, Junbo Luan, Yan Xie, Shusheng Liu, Xueping Zhou
Insect vectors play significant roles in geminivirus spread and evolution in nature. To date little is known about the population dynamics of begomoviruses in their insect vector Bemisia tabaci. In this study we analyzed the genetic variation of tomato yellow leaf curl virus (TYLCV) in its host plant, Solanum lycopersicum, in its transmission vector B. tabaci raised on TYLCV-infected S. lycopersicum plants, and in B. tabaci after being transferred from S. lycopersicum to Gossypium hirsutum. We found that the levels of variability of TYLCV remained stable in S...
November 27, 2017: Scientific Reports
Prerna Vohra, Marie Bugarel, Frances Turner, Guy H Loneragan, Jayne C Hope, John Hopkins, Mark P Stevens
Salmonella enterica is an animal and zoonotic pathogen of worldwide importance. Serovars exist that differ in their host and tissue tropism. Cattle are an important reservoir of human non-typhoidal salmonellosis and contaminated bovine peripheral lymph nodes enter the food chain via ground beef. The relative ability of different serovars to survive within the bovine lymphatic system is poorly understood and constrains the development of control strategies. This problem was addressed by developing a massively-parallel whole genome sequencing method to study mixed-serovar infections in vivoSalmonella serovars differ genetically by naturally occurring single nucleotide polymorphisms (SNPs) in certain genes...
November 27, 2017: Applied and Environmental Microbiology
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