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Dulanthi Weerasekera, Tamara Fastner, Roland Lang, Andreas Burkovski, Lisa Ott
In this study, seven non-toxigenic C. diphtheriae strains and one toxigenic strain were analyzed with regard to their interaction with murine macrophages (BMM) and human THP-1 macrophage-like cells. Proliferation assays with BMM and THP-1 revealed similar intracellular CFUs for the different C. diphtheriae strains independent of the host cell. Strain ISS4060 showed highest intracellular CFUs, while the toxigenic DSM43989 was almost not detectable. This result was confirmed by TLR 9 reporter assays, showing a low signal for DSM43989, indicating that the bacteria are not endocytosed...
May 6, 2019: Virulence
Parvaneh Mehrbod, Sudharsana R Ande, Javad Alizadeh, Shahrzad Rahimizadeh, Aryana Shariati, Hadis Malek, Mohammad Hashemi, Kathleen K M Glover, Affan A Sher, Kevin M Coombs, Saeid Ghavami
Virus infection induces different cellular responses in infected cells. These include cellular stress responses like autophagy and unfolded protein response (UPR). Both autophagy and UPR are connected to programmed cell death I (apoptosis) in chronic stress conditions to regulate cellular homeostasis via Bcl2 family proteins, CHOP and Beclin-1. In this review article we first briefly discuss arboviruses, influenza virus, and HIV and then describe the concepts of apoptosis, autophagy and UPR. Finally, we focus upon how apoptosis, autophagy and UPR are involved in regulation of cellular responses to arboviruses, influenza virus and HIV infections...
April 10, 2019: Virulence
Tomas Erban, Justyna Zitek, Miroslava Bodrinova, Pavel Talacko, Milan Bartos, Jaroslav Hrabak
American foulbrood is a quarantine disease of the honeybee Apis mellifera L. in many countries and contributes greatly to colony losses. We performed a label-free proteomics study of exoprotein fractions produced in vitro by Paenibacillus larvae reference strains of the ERIC I-IV genotypes. A quantitative comparison was performed of previous studied protein-based virulence factors and many newly identified putative virulence factors. Among the multiple proteases identified, key virulence factors included the microbial collagenase ColA and immune inhibitor A (InhA, an analog of the Bacillus thuringiensis protein InhA)...
April 8, 2019: Virulence
Jiao-Yu Wang, Ling Li, Rong-Yao Chai, Hai-Ping Qiu, Zhen Zhang, Yan-Li Wang, Xiao-Hong Liu, Fu-Cheng Lin, Guo-Chang Sun
Peroxisomes are ubiquitous organelles in eukaryotic cells that fulfill multiple important types of metabolism. Pex13 and Pex14 are two key components of the peroxisomal docking complex that play crucial roles in the import of peroxisomal matrix proteins into peroxisomes in yeasts and mammals. In the present work, we investigated the roles of the homologues of Pex13 and Pex14 (Mopex13 and Mopex14) in the rice blast fungus Magnaporthe oryzae. Mopex13 and Mopex14 were distributed on the peroxisomal membrane and were both essential for the maintenance of Mopex14/17 on the peroxisomal membrane...
March 25, 2019: Virulence
Shao Wei, Jianwei Huang, Zhexi Liu, Mengyao Wang, Bingkun Zhang, Zhengxing Lian, Yuming Guo, Hongbing Han
With a broad range of hosts, Salmonella enterica serovar Typhimurium (S. Typhimurium) is the major cause of gastroenteritis in human beings and systemic disease in susceptible mice strains. However, different S. Typhimurium strains differ in regard to virulence and host adaptation. Here, C57BL/6 mice were infected respectively with different S. Typhimurium strains SL1344 (calf), CVCC541 (chicken) and CMCC50115 (mutton) to determine their virulence and host immune responses. It was found that mice were less susceptible to infection by S...
March 21, 2019: Virulence
Lisa Kirchhoff, Maike Olsowski, Peter-Michael Rath, Joerg Steinmann
The black yeast Exophiala dermatitidis is an opportunistic pathogen, causing phaeohyphomycosis in immunosuppressed patients, chromoblastomycosis and fatal infections of the central nervous system in otherwise healthy Asian patients. In addition, it is also regularly isolated from respiratory samples from cystic fibrosis patients, with rates varying between 1% and 19%. Melanin, as part of the cell wall of black yeasts, is one major factor known contributing to the pathogenicity of E. dermatitidis and increased resistance against host defense and anti-infective therapeutics...
March 19, 2019: Virulence
Jingjing Huang, Zhihua Ma, Guowei Zhong, Donald C Sheppard, Ling Lu, Shizhu Zhang
Aspergillus fumigatus is the most prevalent airborne fungal pathogen that causes invasive fungal infections in immunosuppressed individuals. Adaptation to iron limited conditions is crucial for A. fumigatus virulence. To identify novel genes that play roles in adaptation to low iron conditions we performed an insertional mutagenesis screen in A. fumigatus. Using this approach, we identified the tptA gene in A. fumigatus, which shares homology with the Saccharomyces cerevisiae thiamine pyrophosphate (ThPP) transporter encoding gene tpc1...
March 18, 2019: Virulence
Michael Payne, Harshini Weerasinghe, Irma Tedja, Alex Andrianopoulos
Aspartyl proteases are a widely represented class of proteolytic enzymes found in eukaryotes and retroviruses. They have been associated with pathogenicity in a range of disease causing microorganisms. The dimorphic human-pathogenic fungus Talaromyces marneffei has a large expansion of these proteases identified through genomic analyses. Here we characterise the expansion of these genes (pop - paralogue of pep) and their role in T. marneffei using computational and molecular approaches. Many of the genes in this monophyletic family show copy number variation and positive selection despite the preservation of functional regions and possible redundancy...
March 18, 2019: Virulence
Andreas Nerlich, Antje-Maria Lapschies, Thomas P Kohler, Ingrid Cornax, Inga Eichhorn, Oliver Goldmann, Petra Krienke, Simone Bergmann, Victor Nizet, Sven Hammerschmidt, Manfred Rohde, Marcus Fulde
Streptococcus canis is a zoonotic agent that causes serious invasive diseases in domestic animals and humans, but knowledge about its pathogenic potential and underlying virulence mechanisms is limited. Here, we report on the ability of certain S. canis isolates to form large bacterial aggregates when grown in liquid broth. Bacterial aggregation was attributed to the presence and the self-binding activity of SCM, the M protein of S. canis, as evaluated by bacterial sedimentation assays, immunofluorescence- and electron microscopic approaches...
March 4, 2019: Virulence
Sona Sarmirova, Maria Borsanyiova, Brigita Benkoova, Michaela Pospisilova, Rajkumar Arumugam, Katarina Berakova, Pavol Gomolcak, Jay Reddy, Shubhada Bopegamage
Enteroviral infections are frequent, often asymptomatic in humans and during gravidity. The present study is an extension of our previous investigations where we had shown pancreatitis in challenged pups of CVB4-E2 infected dams. Present investigation describes the effect of gestational infection with this virus on the pancreas of both dams and their challenged pups. Gravid CD1 outbred mice were orally infected with CVB4-E2 virus at different gestation times. Pups were challenged orally with the same virus after 25 days of birth...
March 4, 2019: Virulence
Marion Gardette, Simon Le Hello, Patricia Mariani-Kurkdjian, Laetitia Fabre, François Gravey, Annie Garrivier, Estelle Loukiadis, Grégory Jubelin
Enterohaemorrhagic Escherichia coli (EHEC) are foodborne pathogens responsible for bloody diarrhoea and renal failure in humans. While Shiga toxin (Stx) is the cardinal virulence factor of EHEC, its production by E. coli is not sufficient to cause disease and many Shiga-toxin producing E. coli (STEC) strains have never been implicated in human infection. So far, the pathophysiology of EHEC infection is not fully understood and more knowledge is needed to characterize the "auxiliary" factors that enable a STEC strain to cause disease in humans...
February 26, 2019: Virulence
Xuwen Gao, Yingying Ma, Zhuo Wang, Jing Bai, Shuo Jia, Baohua Feng, Yanping Jiang, Wen Cui, Lijie Tang, Yijing Li, Li Wang, Yigang Xu
Clostridium perfringens α-toxin is one of the major virulence factors during C. perfringens infection, causing hemolysis of erythrocytes in various species. Here, genetically engineered Lactobacillus casei (pPG-α/L. casei 393) constitutively expressing the toxoid of C. perfringens α-toxin was generated and its immunogenicity in mice for induction of protective immunity against the α-toxin was evaluated via oral immunization. The α-toxoid was constitutively expressed by pPG-α/L. casei 393 without a specific inducer, as confirmed by western blotting, laser confocal microscopy, and flow cytometry...
February 26, 2019: Virulence
Yao-Wen Wu, Fu Li
Autophagy is a conserved and fundamental cellular process mainly to recycle or eliminate dysfunctional cellular organelles or proteins. As a response to cellular stress, autophagy is used as a defense mechanism to combat the infection with pathogenic bacteria. However, many intracellular bacteria have developed diverse mechanisms to evade recognition, to manipulate the autophagic pathway, and to hijack the autophagosomal compartment for replication. In this review, we discuss recent understandings on how bacteria interact with host autophagy...
December 2019: Virulence
Irene Rodríguez-Arce, Tamim Al-Jubair, Begoña Euba, Ariadna Fernández-Calvet, Celia Gil-Campillo, Sara Martí, Susanna Törnroth-Horsefield, Kristian Riesbeck, Junkal Garmendia
Nutrient iron sequestration is the most significant form of nutritional immunity and causes bacterial pathogens to evolve strategies of host iron scavenging. Cigarette smoking contains iron particulates altering lung and systemic iron homeostasis, which may enhance colonization in the lungs of patients suffering chronic obstructive pulmonary disease (COPD) by opportunistic pathogens such as nontypeable. NTHi is a heme auxotroph, and the NTHi genome contains multiple heme acquisition systems whose role in pulmonary infection requires a global understanding...
December 2019: Virulence
Jesús Arenas, Ruth Bossers-de Vries, José Harders-Westerveen, Herma Buys, Lisette M F Ruuls-van Stalle, Norbert Stockhofe-Zurwieden, Edoardo Zaccaria, Jan Tommassen, Jerry M Wells, Hilde E Smith, Astrid de Greeff
Streptococcus suis is a Gram-positive bacterium and a zoonotic pathogen residing in the nasopharynx or the gastrointestinal tract of pigs with a potential of causing life-threatening invasive disease. It is endemic in the porcine production industry worldwide, and it is also an emerging human pathogen. After invasion, the pathogen adapts to cause bacteremia and disseminates to different organs including the brain. To gain insights in this process, we infected piglets with a highly virulent strain of S. suis, and bacterial transcriptomes were obtained from blood and different organs (brain, joints, and heart) when animals had severe clinical symptoms of infection...
December 2019: Virulence
Wioletta Adamus-Białek, Monika Wawszczak, Michał Arabski, Michał Majchrzak, Martyna Gulba, Dariusz Jarych, Paweł Parniewski, Stanisław Głuszek
Antibiotic therapy and its consequences in bacterial and human aspects are widely investigated. Despite this, the emergence of new multidrug resistant bacteria is still a current problem. The scope of our work included the observation of changes among uropathogenic Escherichia coli strains after the treatment with a subinhibitory concentration of different antibiotics. The sensitive strains with or without virulence factors were incubated with amoxicillin, ciprofloxacin, gentamycin, or tobramycin. After each passage, the E...
December 2019: Virulence
Daniel R Kollath, Karis J Miller, Bridget M Barker
The genus Coccidioides consists of two species: C. immitis and C. posadasii. Prior to 2000, all disease was thought to be caused by a single species, C. immitis. The organism grows in arid to semiarid alkaline soils throughout western North America and into Central and South America. Regions in the United States, with highest prevalence of disease, include California, Arizona, and Texas. The Mexican states of Baja California, Coahuila, Sonora, and Neuvo Leon currently have the highest skin test positive results...
December 2019: Virulence
Ana Florencia Casassa, María Cristina Vanrell, María Isabel Colombo, Roberta A Gottlieb, Patricia Silvia Romano
Autophagy is a catabolic pathway required for cellular and organism homeostasis. Autophagy participates in the innate and adaptive immune responses at different levels. Xenophagy is a class of selective autophagy that involves the elimination of intracellular pathogens. Trypanosoma cruzi is the causative agent of Chagas, a disease that affects 8 million individuals worldwide. Previously, our group has demonstrated that autophagy participates in the invasion of T. cruzi in non-phagocytic cells. In this work we have studied the involvement of autophagy in the development of T...
December 2019: Virulence
Carrie M Long, Paul A Beare, Diane C Cockrell, Charles L Larson, Robert A Heinzen
Coxiella burnetii is an intracellular, gram-negative bacterium that causes the zoonosis Q fever. This disease typically presents as an acute flu-like illness with persistent, focalized infections occurring less frequently. Clinical outcomes of Q fever have been associated with distinct genomic groups of C. burnetii, suggesting that gene content is responsible for virulence potential. To investigate this hypothesis, the virulence of thirteen C. burnetii strains (representing genomic groups I-VI) was evaluated in a guinea pig infection model by intraperitoneal injection...
December 2019: Virulence
Bingbing Zong, Yanyan Zhang, Xiangru Wang, Manli Liu, Tongchao Zhang, Yongwei Zhu, Yucheng Zheng, Linlin Hu, Pei Li, Huanchun Chen, Chen Tan
Porcine extra-intestinal pathogenic Escherichia coli (ExPEC) causes great economic losses to the pig industry and poses a serious threat to public health worldwide. Some secreted virulence factors have been reported to be involved in the pathogenicity of the infection caused by ExPEC. Type-VI secretion system (T6SS) is discovered in many Gram-negative bacteria and contributes to the virulence of pathogenic bacteria. Valine-glycine repeat protein G (VgrG) has been reported as an important component of the functional T6SS...
December 2019: Virulence
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