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Infections in compromised host

Nicole Robbins, Gerard D Wright, Leah E Cowen
Invasive fungal infections are becoming an increasingly important cause of human mortality and morbidity, particularly for immunocompromised populations. The fungal pathogens Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus collectively contribute to over 1 million human deaths annually. Hence, the importance of safe and effective antifungal therapeutics for the practice of modern medicine has never been greater. Given that fungi are eukaryotes like their human host, the number of unique molecular targets that can be exploited for drug development remains limited...
October 2016: Microbiology Spectrum
Aditya K Sharma, Divya Arora, Lalit K Singh, Aakriti Gangwal, Andaleeb Sajid, Virginie Molle, Yogendra Singh, Vinay K Nandicoori
Protein phosphatases play vital roles in phosphorylation-mediated cellular signaling. While there are 11 serine/threonine protein kinases in Mycobacterium tuberculosis, only one serine/threonine phosphatase, PstP, has been identified. Although PstP has been biochemically characterized and multiple in vitro substrates identified, its physiological role has not yet been elucidated. In this study we have investigated the impact of PstP on cell growth and survival of the pathogen in the host. Overexpression of PstP led to elongated cells and partially compromised survival...
October 7, 2016: Journal of Biological Chemistry
John Moat, Athanasios Rizoulis, Graeme Fox, Mathew Upton
The domestic environment can be a source of pathogenic bacteria. We show here that domestic shower hoses may harbour potentially pathogenic bacteria and fungi. Well-developed biofilms were physically removed from the internal surface of shower hoses collected in four locations in England and Scotland. Amplicon pyrosequencing of 16S and 18S rRNA targets revealed the presence of common aquatic and environmental bacteria, including members of the Actinobacteria, Alphaproteobacteria, Bacteroidetes and non-tuberculous Mycobacteria...
October 2016: Journal of Water and Health
Richard L Hodinka
Acute upper and lower respiratory infections are a major public health problem and a leading cause of morbidity and mortality worldwide. At greatest risk are young children, the elderly, the chronically ill, and those with suppressed or compromised immune systems. Viruses are the predominant cause of respiratory tract illnesses and include RNA viruses such as respiratory syncytial virus, influenza virus, parainfluenza virus, metapneumovirus, rhinovirus, and coronavirus. Laboratory testing is required for a reliable diagnosis of viral respiratory infections, as a clinical diagnosis can be difficult since signs and symptoms are often overlapping and not specific for any one virus...
August 2016: Microbiology Spectrum
Deepika Sharma, Brijendra Kumar Tiwari, Subhash Mehto, Cecil Antony, Gunjan Kak, Yogendra Singh, Krishnamurthy Natarajan
The prevalence of Mycobacterium tuberculosis (M. tb) strains eliciting drug resistance has necessitated the need for understanding the complexities of host pathogen interactions. The regulation of calcium homeostasis by Voltage Gated Calcium Channel (VGCCs) upon M. tb infection has recently assumed importance in this area. We previously showed a suppressor role of VGCC during M. tb infections and recently reported the mechanisms of its regulation by M. tb. Here in this report, we further characterize the role of VGCC in mediating defence responses of macrophages during mycobacterial infection...
2016: PloS One
Juan Liu, XueJiao Zhang, YueKun Yang, Ni Hong, GuoPing Wang, Aiming Wang, LiPing Wang
BACKGROUND: Heat treatment (known as thermotherapy) together with in vitro culture of shoot meristem tips is a commonly used technology to obtain virus-free germplasm for the effective control of virus diseases in fruit trees. RNA silencing as an antiviral defense mechanism has been implicated in this process. To understand if high temperature-mediated acceleration of the host antiviral gene silencing system in the meristem tip facilitates virus-derived small interfering RNAs (vsiRNA) accumulation to reduce the viral RNA titer in the fruit tree meristem tip cells, we used the Apple stem grooving virus (ASGV)-Pyrus pyrifolia pathosystem to explore the possible roles of vsiRNA in thermotherapy...
October 6, 2016: Virology Journal
Arunava Bandyopadhaya, Amy Tsurumi, Damien Maura, Kate L Jeffrey, Laurence G Rahme
The mechanisms by which pathogens evade elimination without affecting host fitness are not well understood. For the pathogen Pseudomonas aeruginosa, this evasion appears to be triggered by excretion of the quorum-sensing molecule 2-aminoacetophenone, which dampens host immune responses and modulates host metabolism, thereby enabling the bacteria to persist at a high burden level. Here, we examined how 2-aminoacetophenone trains host tissues to become tolerant to a high bacterial burden, without compromising host fitness...
October 3, 2016: Nature Microbiology
E A F Camargo, J T F Camargo, M F Neves, L F Simões, L A D Bastos, L A Magalhães, E M Zanotti-Magalhães
Fluctuations in population density of planorbid hosts of S. mansoni are influenced by climatic factors. The knowledge about interference from changes in water temperature in these populations is an important aspect of the epidemiology of schistosomiasis. In this experiment, it is explored the influence of different temperatures on the development of Schistosoma mansoni in Biomphalaria glabrata melanic and albino variants. The results indicated an intrinsic relationship between temperature and development of the parasite in the intramollusc phase, independent of the pigmentation of the mantle of the molluscs...
September 26, 2016: Brazilian Journal of Biology, Revista Brasleira de Biologia
Zachary M Parker, Tracy Jo Pasieka, George A Parker, David A Leib
: The interferon (IFN) response to viral pathogens is critical for host survival. In humans and mouse models, defects in IFN responses can result in lethal herpes simplex type-1 (HSV-1) infections, usually from encephalitis. Although rare, HSV-1 can also cause fulminant hepatic failure which is often fatal. While herpes simplex encephalitis has been extensively studied, HSV-1 generalized infections and subsequent acute liver failure are less well understood. We previously demonstrated that IFNαβγR(-/-) mice are exquisitely susceptible to liver infection following corneal infection with HSV-1...
September 28, 2016: Journal of Virology
Chao Wang, John R McPherson, Lian-Hui Zhang, Steve Rozen, Kanaga Sabapathy
Pseudomonas aeruginosa is an opportunistic pathogen which infects cystic fibrosis and cancer patients with compromised immune systems. LasR is a master regulator which controls the virulence of P. aeruginosa in response to bacterial cell-density and host signals. During infection, lasR is frequently mutated, conferring P. aeruginosa a growth advantage in hosts and enhances resistance to widely used antibiotics. However, the mechanistic basis of lasR mutation is not well understood. We have tested here the hypothesis that transcription strength is a contributory determinant of lasR mutagenesis...
October 2016: DNA Repair
Tackmin Kwon
The efficiency of Agrobacterium-mediated transformation in plants depends on the virulence of Agrobacterium strains, the plant tissue culture conditions, and the susceptibility of host plants. Understanding the molecular interactions between Agrobacterium and host plant cells is crucial when manipulating the susceptibility of recalcitrant crop plants and protecting orchard trees from crown gall disease. It was discovered that Arabidopsis voltage-dependent anion channel 1 (atvdac1) mutant has drastic effects on Agrobacterium-mediated tumorigenesis and growth developmental phenotypes, and that these effects are dependent on a Ws-0 genetic background...
September 2016: Molecules and Cells
Julio Gallego-Delgado, Upal Basu-Roy, Maureen Ty, Matilde Alique, Cristina Fernandez-Arias, Alexandru Movila, Pollyanna Gomes, Ada Weinstock, Wenyue Xu, Innocent Edagha, Samuel C Wassmer, Thomas Walther, Marta Ruiz-Ortega, Ana Rodriguez
Cerebral malaria is characterized by cytoadhesion of Plasmodium falciparum-infected red blood cells (Pf-iRBCs) to endothelial cells in the brain, disruption of the blood-brain barrier, and cerebral microhemorrhages. No available antimalarial drugs specifically target the endothelial disruptions underlying this complication, which is responsible for the majority of malaria-associated deaths. Here, we have demonstrated that ruptured Pf-iRBCs induce activation of β-catenin, leading to disruption of inter-endothelial cell junctions in human brain microvascular endothelial cells (HBMECs)...
October 3, 2016: Journal of Clinical Investigation
Joaquina X Mascarenhas, Nikolay Korokhov, Lisa Burger, Ademola Kassim, Jason Tuter, Daniel Miller, Trissa Borgschulte, Henry J George, Audrey Chang, David J Pintel, David Onions, Kevin J Kayser
Contamination by the parvovirus minute virus of mice (MVM) remains a challenge in Chinese hamster ovary (CHO) biopharmaceutical production processes. Although infrequent, infection of a bioreactor can be catastrophic for a manufacturer, can impact patient drug supply and safety, and can have regulatory implications. We evaluated engineering a CHO parental cell line (CHOZN(®) GS(-/-) ) to create a new host cell line that is resistant to MVM infection by modifying the major receptors used by the virus to enter cells...
September 19, 2016: Biotechnology and Bioengineering
Javier Cabrera-Perez, Vladimir P Badovinac, Thomas S Griffith
Sepsis is a poorly understood syndrome of systemic inflammation responsible for hundreds of thousands of deaths every year. The integrity of the gut epithelium and competence of adaptive immune responses are notoriously compromised during sepsis, and the prevalent assumption in the scientific and medical community is that intestinal commensals have a detrimental role in the systemic inflammation and susceptibility to nosocomial infections seen in critically ill, septic patients. However, breakthroughs in the last decade provide strong credence to the idea that our mucosal microbiome plays an essential role in adaptive immunity, where a human host and its prokaryotic colonists seem to exist in a carefully negotiated armistice with compromises and benefits that go both ways...
September 15, 2016: Experimental Biology and Medicine
Wei X Teo, Markus C Kerr, Rohan D Teasdale
The intracellular pathogen Salmonella enterica servovar Typhimurium (S.typhimurium) modulates the host cell's phosphoinositide (PI) metabolism to establish its intracellular replicative niche, the Salmonella-containing vacuole (SCV). Upon invasion, phosphoinositide 3-phosphate (PI(3)P) and other early endosomal markers are rapidly recruited to and remain associated with the SCV throughout its early maturation. While the phosphoinositide 3-phosphatase myotubularin 4 (MTMR4) has an established role in regulating autophagy and cellular PI(3)P-content, two processes associated with the intracellular survival of S...
2016: Frontiers in Cellular and Infection Microbiology
Ling-Ling An, Jacob V Gorman, Geoffrey Stephens, Bonnie Swerdlow, Paul Warrener, Jessica Bonnell, Tomas Mustelin, Michael Fung, Roland Kolbeck
Severe bacterial infection results in both uncontrolled inflammation and immune suppression in septic patients. Although there is ample evidence that complement activation provokes overwhelming pro-inflammatory responses, whether or not it plays a role in immune suppression in this case is unclear. Here, we identify that complement C5a directly participates in negative regulation of immune responses to bacteria-induced inflammation in an ex vivo model of human whole blood. Challenge of whole blood with heat-killed Pseudomonas aeruginosa induces PD-L1 expression on monocytes and the production of IL-10 and TGF-β, which we show to be inhibited by C5a blockade...
2016: Scientific Reports
M Daben J Libardo, Vitaliy Y Gorbatyuk, Alfredo M Angeles-Boza
Ticks transmit multiple pathogens to different hosts without compromising their health. Their ability to evade microbial infections is largely a result of their effective innate immune response including various antimicrobial peptides. Therefore, a deep understanding of how ticks (and other arthropod vectors) control microbial loads could lead to the design of broad-spectrum antimicrobial agents. In this paper we study the role of the amino-terminal copper and nickel (ATCUN)-binding sequence in the peptide ixosin, isolated from the salivary glands of the hard tick Ixodes sinensis...
January 8, 2016: ACS Infectious Diseases
Moon Y F Tay, Kate Smith, Ivan H W Ng, Kitti W K Chan, Yongqian Zhao, Eng Eong Ooi, Julien Lescar, Dahai Luo, David A Jans, Jade K Forwood, Subhash G Vasudevan
Dengue virus NS5 is the most highly conserved amongst the viral non-structural proteins and is responsible for capping, methylation and replication of the flavivirus RNA genome. Interactions of NS5 with host proteins also modulate host immune responses. Although replication occurs in the cytoplasm, an unusual characteristic of DENV2 NS5 is that it localizes to the nucleus during infection with no clear role in replication or pathogenesis. We examined NS5 of DENV1 and 2, which exhibit the most prominent difference in nuclear localization, employing a combination of functional and structural analyses...
September 2016: PLoS Pathogens
Jonathan E Schmitz, Takako Taniguchi, Naoaki Misawa, Timothy L Cover
: Helicobacter cinaedi is an emerging opportunistic pathogen associated with infections of diverse anatomic sites. Nevertheless, the species demonstrates fastidious axenic growth-it is described as requiring a microaerobic atmosphere, along with a strong preference for supplemental H2-gas. In this context, we examined the hypothesis that in vitro growth of H. cinaedi could be enhanced by co-culture with human epithelial cells. When inoculated (in Ham's F12) over Caco-2 monolayers, the type strain (ATCC BAA-847(T)) gained the ability to proliferate under H2-free aerobic conditions...
September 9, 2016: Applied and Environmental Microbiology
Yuka Kobayashi, Takeshi Watanabe
We previously generated artificial lymph node-like tertiary lymphoid organs (artTLOs) in mice using lymphotoxin α-expressing stromal cells. Here, we show the construction of transplantable and functional artTLOs by applying soluble factors trapped in slow-releasing gels in the absence of lymphoid tissue organizer stromal cells. The resultant artTLOs were easily removable, transplantable, and were capable of attracting memory B and T cells. Importantly, artTLOs induced a powerful antigen-specific secondary immune response, which was particularly pronounced in immune-compromised hosts...
2016: Frontiers in Immunology
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