Aspergillus fumigatus adhesion factors in dormant conidia revealed through comparative phenotypic and transcriptomic analyses
Abstract
Aspergillus fumigatus is an important fungal pathogen of humans. Inhaled conidia of A. fumigatus adhere to pulmonary epithelial cells, causing oportunistic infection. However, little is known about the molecular mechanism of the adherence of resting conidia. Fungal molecules adhesive to host cells are presumed to be displayed on the conidial surface during conidial formation as a result of changes in gene expression. Therefore, we exhaustively searched for adhesion molecules by comparing the phenotypes and the gene expression profiles of A. fumigatus strains that have conidia showing either high or low adherence t...
Source: Cellular Microbiology - November 1, 2017 Category: Microbiology Authors: Azusa Takahashi ‐Nakaguchi, Kanae Sakai, Hiroki Takahashi, Daisuke Hagiwara, Takahito Toyotome, Hiroji Chibana, Akira Watanabe, Takashi Yaguchi, Masashi Yamaguchi, Katsuhiko Kamei, Tohru Gonoi Tags: RESEARCH ARTICLE Source Type: research
Neutrophils differentially attenuate immune response to Aspergillus infection through complement receptor 3 and induction of myeloperoxidase
Summary
Invasive aspergillosis (IA) remains a major cause of morbidity in immunocompromised hosts. This is due to the inability of the host immunity to respond appropriately to Aspergillus. An established risk factor for IA is neutropenia which is encountered by patients undergoing chemotherapy. Herein we investigate the role of neutrophils in modulating host response to Aspergillus. We found that neutrophils had the propensity to suppress proinflammatory cytokine production but through different mechanisms for specific cytokines. Cellular contact was requisite for the modulation of interleukin‐1 beta production by Asper...
Source: Cellular Microbiology - October 31, 2017 Category: Microbiology Authors: Jessamine G. Goh, Sharada Ravikumar, Mar Soe Win, Qiong Cao, Ai Ling Tan, Joan H.J. Lim, Winnie Leong, Raoul Herbrecht, Peter F. Troke, Bart Jan Kullberg, Mihai G. Netea, Wee Joo Chng, Yock Young Dan, Louis Y.A. Chai Tags: RESEARCH ARTICLE Source Type: research
Proteomics analysis of Medicago truncatula response to infection by the phytopathogenic bacterium Ralstonia solanacearum points to jasmonate and salicylate defence pathways
Abstract
The infection of the model legume Medicago truncatula with Ralstonia solanacearum GMI1000 gives rise to bacterial wilt disease via colonization of roots. The root and leaf responses to early infection (one and three days post infection) were characterized to investigate the molecular mechanisms of plant resistance or susceptibility. A proteomics approach based on pools of susceptible and resistant recombinant inbred lines was used to specifically target the mechanisms for tolerance. Differential abundances were evidenced for proteins involved in defense (e.g. PR5, PR10 or Kunitz protease inhibitors) and signaling ...
Source: Cellular Microbiology - October 31, 2017 Category: Microbiology Authors: Ahad Yamchi Tags: RESEARCH ARTICLE Source Type: research
Tracking elusive cargo: Illuminating spatio ‐temporal type 3 effector protein dynamics using reporters
Summary
Type 3 secretion systems (T3SS) form an integral part of the arsenal of many pathogenic bacteria. These injection machines, together with their cargo of subversive effector proteins are capable of manipulating the cellular environment of the host in order to ensure persistence of the pathogen. In order to fully appreciate the functions of Type 3 effectors it is necessary to gain spatio‐temporal knowledge of each effector during the process of infection. A number of genetic modifications have been exploited in order to reveal effector protein secretion, translocation and subsequent activity and localisation within...
Source: Cellular Microbiology - October 31, 2017 Category: Microbiology Authors: Nicky O'Boyle, James P.R. Connolly, Andrew J. Roe Tags: MICROREVIEW Source Type: research
Proteomics analysis of Medicago truncatula response to infection by the phytopathogenic bacterium Ralstonia solanacearum points to jasmonate and salicylate defence pathways
Cellular Microbiology,Volume 20, Issue 4, April 2018. (Source: Cellular Microbiology)
Source: Cellular Microbiology - October 30, 2017 Category: Microbiology Source Type: research
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Cellular Microbiology,Volume 20, Issue 4, April 2018. (Source: Cellular Microbiology)
Source: Cellular Microbiology - October 30, 2017 Category: Microbiology Source Type: research
Bacterial lipoproteins and other factors released by Francisella tularensis modulate human neutrophil lifespan: effects of a TLR1 SNP on apoptosis inhibition.
ABSTRACT
F. tularensis infects several cell types including neutrophils, and aberrant neutrophil accumulation contributes to tissue destruction during tularemia. We demonstrated previously that F. tularensis strains Schu S4 and LVS markedly delay human neutrophil apoptosis and thereby prolong cell lifespan, but the bacterial factors that mediate this aspect of virulence are undefined. Herein, we demonstrate that bacterial conditioned medium (CM) can delay apoptosis in the absence of direct infection. Biochemical analyses show that CM contained F. tularensis surface factors as well as outer membrane components. Our previous...
Source: Cellular Microbiology - October 24, 2017 Category: Microbiology Authors: Lauren C. Kinkead, Laura C. Whitmore, Jenna M. McCracken, Joshua R. Fletcher, Brandi B. Ketelsen, Justin W. Kaufman, Bradley D. Jones, David S. Weiss, Jason H. Barker, Lee ‐Ann H. Allen Tags: RESEARCH ARTICLE Source Type: research
Leucocyte recruitment and molecular fortification of keratinocytes triggered by streptococcal M1 protein
This study was undertaken to investigate if soluble M1 protein can aggravate the severity of streptococcal skin infections in respect to inflammation, leucocyte recruitment, and tissue remodelling as seen in patients with cellulitis and necrotizing fasciitis. We found that HaCaT cells are able to recruit activated leucocytes when encountering M1 protein. Neither the bacterial protein nor activated leucocytes caused cell damage on HaCaT cells, instead HaCaT cells responded to the bacterial virulence factor by releasing several proteins protective against bacterial infection and leucocyte responses. However, although not cyt...
Source: Cellular Microbiology - October 19, 2017 Category: Microbiology Authors: Sandra T. Persson, Simon Hauri, Johan Malmstr öm, Heiko Herwald Tags: RESEARCH ARTICLE Source Type: research
Functional analysis of Toxoplasma lactate dehydrogenases suggests critical roles of lactate fermentation for parasite growth in vivo
In this study, we knocked out the two LDH genes individually and in combination, and found that neither gene was required for tachyzoite growth in vitro under standard growth conditions. However during infection in mice, Δldh1 and Δldh1 Δldh2 mutants were unable to propagate and displayed significant virulence attenuation and cyst formation defects. LDH2 only played minor roles in these processes. To further elucidate the mechanisms underlying the critical requirement of LDH in vivo, we found that Δldh1 Δldh2 mutants replicated significantly more slowly than wild type parasites when cultured under conditions with phys...
Source: Cellular Microbiology - October 13, 2017 Category: Microbiology Authors: Ningbo Xia, Jichao Yang, Shu Ye, Lihong Zhang, Yanqin Zhou, Junlong Zhao, L. David Sibley, Bang Shen Tags: RESEARCH ARTICLE Source Type: research
Issue Information
No abstract is available for this article. (Source: Cellular Microbiology)
Source: Cellular Microbiology - October 12, 2017 Category: Microbiology Tags: ISSUE INFORMATION Source Type: research
A novel in vitro model for haematogenous spreading of S. aureus device biofilms demonstrating clumping dispersal as an advantageous dissemination mechanism
Summary
Staphylococcus aureus is able to disseminate from vascular device biofilms to the blood and organs, resulting in life‐threatening infections such as endocarditis. The mechanisms behind spreading are largely unknown, especially how the bacterium escapes immune effectors and antibiotics in the process. Using an in vitro catheter infection model, we studied S. aureus biofilm growth, late‐stage dispersal, and reattachment to downstream endothelial cell layers. The ability of the released biofilm material to resist host response and disseminate in vivo was furthermore studied in whole blood and phagocyte survival as...
Source: Cellular Microbiology - October 4, 2017 Category: Microbiology Authors: R. B. Gr ønnemose, K. L. Saederup, H. J. Kolmos, S. W. K. Hansen, C. A. Asferg, K. J. Rasmussen, Y. Palarasah, T. E. Andersen Tags: RESEARCH ARTICLE Source Type: research
Leukocyte recruitment and molecular fortification of keratinocytes triggered by streptococcal M1 protein
Summary
Streptococcus pyogenes of the M1 serotype is commonly associated with invasive streptococcal infections and development of streptococcal toxic shock syndrome. The M1 protein is a powerful inducer of inflammatory responses for several human cell types, but the reason why M1 protein‐related strains is over‐represented in invasive streptococcal diseases is still not understood. The present study was undertaken to investigate if soluble M1 protein can aggravate the severity of streptococcal skin infections in respect to inflammation, leukocyte recruitment, and tissue remodeling as seen in patients with cellulitis a...
Source: Cellular Microbiology - October 3, 2017 Category: Microbiology Authors: Sandra T. Persson, Simon Hauri, Johan Malmstr öm, Heiko Herwald Tags: RESEARCH ARTICLE Source Type: research
Novel T3SS Effector EseK in Edwardsiella piscicida is Chaperoned by EscH and EscS to Express Virulence
ABSTRACT
Bacterium usually utilizes type III secretion systems (T3SS) to deliver effectors directly into host cells with the aids of chaperones. Hence, it is very important to identify bacterial T3SS effectors and chaperones for better understanding of host‐pathogen interactions. Edwardsiella piscicida is an invasive enteric bacterium, which infects a wide range of hosts from fish to human. Given E. piscicida encodes a functional T3SS to promote infection, very few T3SS effectors and chaperones have been identified in this bacterium so far. Here, we reported that EseK is a new T3SS effector protein translocated by E. pis...
Source: Cellular Microbiology - October 1, 2017 Category: Microbiology Authors: Huifang Cao, Cuiting Yang, Shu Quan, Tianjian Hu, Lingzhi Zhang, Yuanxing Zhang, Dahai Yang, Qin Liu Tags: RESEARCH ARTICLE Source Type: research
Mechanisms and functions of guanylate ‐binding proteins and related interferon‐inducible GTPases: roles in intracellular lysis of pathogens
Abstract
Guanylate‐binding proteins (GBPs) are a group interferon‐inducible GTPases within the constellation of the dynamin GTPase superfamily. These proteins restrict the replication of intracellular pathogens in both immune and non‐immune cells. GBPs and their related family members Immunity‐related GTPases (IRGs) target and lyse the membrane of the pathogen‐containing vacuole, destroying the residential niche of vacuolar protozoal and bacterial pathogens. They also prevent virion infectivity and target replication complexes of RNA viruses. The exciting concept that GBPs and IRGs can directly target the membran...
Source: Cellular Microbiology - October 1, 2017 Category: Microbiology Authors: Chinh C. Ngo, Si Ming Man Tags: MICROREVIEW Source Type: research
Sweet host revenge: galectins and GBPs join forces at broken membranes
Summary
Most bacterial pathogens enter and exit eukaryotic cells during their journey through the vertebrate host. In order to endure inside a eukaryotic cell, bacterial invaders commonly employ bacterial secretion systems to inject host cells with virulence factors that co‐opt the host's membrane trafficking systems and thereby establish specialized pathogen‐containing vacuoles (PVs) as intracellular niches permissive for microbial growth and survival. To defend against these microbial adversaries hiding inside PVs, host organisms including humans evolved an elaborate cell‐intrinsic armory of antimicrobial weapons t...
Source: Cellular Microbiology - October 1, 2017 Category: Microbiology Authors: J örn Coers Tags: MICROREVIEW Source Type: research
