Read by QxMD icon Read

Virulence Regulation

Sukhendu Mandal, Semanti Ghosh, Debabrata Sinha, Soham Seal, Avisek Mahapa, Soumitra Polley, Deeya Saha, Keya Sau, Angshuman Bagchi, Subrata Sau
SarA, a winged-helix DNA binding protein, is a global virulence regulator in Staphylococcus aureus. The putative DNA binding region of SarA is located between amino acid residues Leu 53 and Gln 97. Previous studies have demonstrated that residues at positions 84, 88, 89, and 90 are critical for its function. To precisely understand the roles of the DNA binding residues, we have investigated nine mutants of a recombinant SarA (rSarA) along with the rSarA mutants carrying mutations at the above four positions...
March 12, 2018: International Journal of Biological Macromolecules
Jianrong Li, Qilin Yu, Bing Zhang, Chenpeng Xiao, Tianyu Ma, Xiao Yi, Chao Liang, Mingchun Li
Cellular stresses could activate several response processes, such as the unfolded protein response (UPR), autophagy and oxidative stress response to restore cellular homeostasis or render cell death. Herein, we identified the Candida albicans stress-associated endoplasmic reticulum protein 1 (SERP1), also known as Ysy6, which was involved in endoplasmic reticulum (ER) stress response. We found that deletion of both SERP1/YSY6 and ATG8 led to hypersensitivity to tunicamycin (TN), and resulted in severe mitochondrial dysfunction under this stress...
March 6, 2018: International Journal of Medical Microbiology: IJMM
Olivier Poupel, Caroline Proux, Bernd Jagla, Tarek Msadek, Sarah Dubrac
The success of Staphylococcus aureus, as both a human and animal pathogen, stems from its ability to rapidly adapt to a wide spectrum of environmental conditions. Two-component systems (TCSs) play a crucial role in this process. Here, we describe a novel staphylococcal virulence factor, SpdC, an Abi-domain protein, involved in signal sensing and/or transduction. We have uncovered a functional link between the WalKR essential TCS and the SpdC Abi membrane protein. Expression of spdC is positively regulated by the WalKR system and, in turn, SpdC negatively controls WalKR regulon genes, effectively constituting a negative feedback loop...
March 2018: PLoS Pathogens
Qing Cai, Sen-Miao Tong, Wei Shao, Sheng-Hua Ying, Ming-Guang Feng
Histone acetyltransferases (HATs) and deacetylases (HDACs) maintain dynamics of lysine acetylation/deacetylation on histones and non-histone substrates involved in gene regulation and cellular events. Hos2 is a class I HDAC that deacetylates unique histone H4-K16 site in yeasts. Here, we report that orthologous Hos2 deacetylates H4-K16 and is also involved in the acetylation of histone H3-K56 and the phosphorylation of histone H2A-S129 and cyclin-dependent kinase 1 CDK1-Y15 in Beauveria bassiana, a filamentous fungal insect pathogen...
March 15, 2018: Cellular 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
Arwa Abu Khweek, Amal O Amer
Legionella pneumophila ( L. pneumophila ) is an opportunistic waterborne pathogen and the causative agent for Legionnaires' disease, which is transmitted to humans via inhalation of contaminated water droplets. The bacterium is able to colonize a variety of man-made water systems such as cooling towers, spas, and dental lines and is widely distributed in multiple niches, including several species of protozoa In addition to survival in planktonic phase, L. pneumophila is able to survive and persist within multi-species biofilms that cover surfaces within water systems...
2018: Frontiers in Cellular and Infection Microbiology
Qingyun Dai, Lei Xu, Lu Xiao, Kaixiang Zhu, Yunhong Song, Changfu Li, Lingfang Zhu, Xihui Shen, Yao Wang
Urease acts as an important acid resistance system and virulence factor that is widespread among microorganisms. RovM is a global regulator that regulates a series of genes and pathways including acid survival systems in the enteric bacterium Yersinia pseudotuberculosis (Yptb) . However, whether RovM regulates the urease activity in Yptb was still unknown. In this study, by using qualitative and quantitative urease assays, we show that the urease expression responds to nutrient conditions and the RovM protein represses urease expression by binding to its promoter...
2018: Frontiers in Microbiology
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
Yinghang Liu, Kunlong Yang, Qiuping Qin, Guinan Lin, Tianran Hu, Zhangling Xu, Shihua Wang
The heterotrimeric G proteins are critical for signal transduction and function in numerous biological processes including vegetative growth, asexual development and fungal virulence in fungi. Here, we identified four G protein alpha subunits (GanA, GpaB, FadA and GaoC) in the notorious Aflatoxin-producing fungus Aspergillus flavus . GanA, GpaB and FadA have homologues in other fungal species, while GaoC is a novel one. Here, we showed that the loss function of gpaB displayed a defect in conidiophore formation and considerably reduced expression levels of conidia-specific genes brlA and abaA ...
March 10, 2018: Toxins
Xiliang Qi, Xiaokang Li, Huiming Guo, Ning Guo, Hongmei Cheng
The soil-borne ascomycete fungus Verticillium dahliae causes vascular wilt disease and can seriously diminish the yield and quality of important crops. Functional analysis of growth- and pathogenicity-related genes is essential for revealing the pathogenic molecular mechanism of V. dahliae . Phospholipase is an important virulence factor in fungi that hydrolyzes phospholipids into fatty acid and other lipophilic substances and is involved in hyphal development. Thus far, only a few V. dahliae phospholipases have been identified, and their involvement in V...
March 13, 2018: Genes
Donghoon Kang, Daniel R Kirienko, Phillip Webster, Alfred L Fisher, Natalia V Kirienko
Pseudomonas aeruginosa, a re-emerging, opportunistic human pathogen, encodes a variety of virulence determinants. Pyoverdine, a siderophore produced by this bacterium, is essential for pathogenesis in mammalian infections. This observation is generally attributed to its roles in acquiring iron and/or regulating other virulence factors. Here we report that pyoverdine translocates into the host, where it binds and extracts iron from the host prior to its eventual exit. Pyoverdine-mediated iron extraction damages host mitochondria, disrupting their function and triggering mitochondrial turnover via autophagy...
March 13, 2018: Virulence
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
Nishanth Makthal, Hackwon Do, Arica R VanderWal, Randall J Olsen, James M Musser, Muthiah Kumaraswami
Bacterial virulence factor production is a highly coordinated process. The temporal pattern of bacterial gene expression varies in different host anatomic sites to overcome niche-specific challenges. The human pathogen group A streptococcus (GAS) produces a potent secreted protease, SpeB, that is crucial for pathogenesis. Recently, we discovered that a quorum-sensing pathway comprised of a leaderless short peptide, SpeB-inducing peptide (SIP), and cytosolic global regulator, RopB, controls speB expression in concert with bacterial population density...
March 12, 2018: Infection and Immunity
Divya Arora, Yogesh Chawla, Basanti Malakar, Archana Singh, Vinay Kumar Nandicoori
The cell wall of Mycobacterium tuberculosis (Mtb) is a complex structure that protects the pathogen in hostile environments. Peptidoglycan (PG), which helps determine the morphology of the cell envelope, undergoes substantial remodeling under stress. This meshwork of linear chains of sugars, crosslinked through attached peptides, is generated through the sequential action of enzymes termed transglycosylases and transpeptidases. The Mtb genome encodes two classical transglycosylases and four transpeptidases, the functions of which are not fully elucidated...
March 12, 2018: Journal of Biological Chemistry
Jee Youn Hwang, Kesavan Markkandan, Mun Gyeong Kwon, Jung Soo Seo, Seung-Il Yoo, Seong Don Hwang, Maeng-Hyun Son, Junhyung Park
Olive flounder (Paralichthys olivaceus) is one of the most valuable marine aquatic species in South Korea and faces tremendous exposure to the viral hemorrhagic septicemia virus (VHSV). Given the growing importance of flounder, it is therefore essential to understand the host defense of P. olivaceus against VHSV infection, but studies on its immune mechanism are hindered by the lack of genomic resources. In this study, the P. olivaceus was infected with disease-causing VHSV isolates, ADC-VHS2012-11 and ADC-VHS2014-5 which showed moderate virulent (20% mortality) and high virulent (65% mortality), in order to investigate the effect of difference in pathogenicity in head kidney during 1, 3, 7 days of post-infection using Illumina sequencing...
March 9, 2018: Fish & Shellfish Immunology
Gaby E R Monteiro, Petrus Jansen Van Vanuren, Paul J Wichgers Schreur, Lieza Odendaal, Sarah J Clift, Jeroen Kortekaas, Janusz T Paweska
The NSs protein encoded by the S segment of Rift Valley fever virus (RVFV) is the major virulence factor, counteracting the host innate antiviral defence. It contains five highly conserved cysteine residues at positions 39, 40, 149, 178 and 194, which are thought to stabilize the tertiary and quaternary structure of the protein. Here, we report significant differences between clinical, virological, histopathological and host gene responses in BALB/c mice infected with wild-type RVFV (wtRVFV) or a genetic mutant having a double cysteine-to-serine substitution at residues 39 and 40 of the NSs protein (RVFV-C39S/C40S)...
March 9, 2018: Virus Research
Pei Lin Zhuang, Li Xia Yu, Juan Kun Liao, Yan Zhou, Huan Cai Lin
BACKGROUND: The VicRK two-component signalling system regulates virulence and cariogenicity in Streptococcus mutans (S. mutans). The purpose of this study was to explore the genetic polymorphisms of the vicR and vicK genes, which are associated with dental caries in children with S. mutans. METHODS: In this study, 121 (from each group) clinical S. mutans strains were isolated from caries-free children and children with high-severity caries to sequence the vicR and vicK genes...
March 12, 2018: BMC Oral Health
Sakshi Agarwal, Prabhakar Tiwari, Amar Deep, Saqib Kidwai, Shamba Gupta, Krishan Gopal Thakur, Ramandeep Singh
Toxin-antitoxin (TA) systems are bicistronic genetic modules that are ubiquitously present in bacterial genomes. Mycobacterium tuberculosis (Mtb) genome encodes for 90 putative TA systems and these are considered to be associated with maintenance of bacterial genomic stability or its survival under unfavorable environment. Majority of these in Mtb have been annotated as belonging to the Virulence associated protein B and C (VapBC) family. However, their precise role in bacterial physiology has not been elucidated...
February 24, 2018: Journal of Infectious Diseases
Moran Brenner, Lior Lobel, Ilya Borovok, Nadejda Sigal, Anat A Herskovits
Listeria monocytogenes (Lm) is a saprophyte and intracellular pathogen. Transition to the pathogenic state relies on sensing of host-derived metabolites, yet it remains unclear how these are recognized and how they mediate virulence gene regulation. We previously found that low availability of isoleucine signals Lm to activate the virulent state. This response is dependent on CodY, a global regulator and isoleucine sensor. Isoleucine-bound CodY represses metabolic pathways including branched-chain amino acids (BCAA) biosynthesis, however under BCAA depletion, as occurs during infection, BCAA biosynthesis is upregulated and isoleucine-unbound CodY activates virulence genes...
March 12, 2018: PLoS Genetics
Munmun Nandi, Jacqueline MacDonald, Peng Liu, Brian Weselowski, Ze-Chun Yuan
Bacterial canker disease is considered one of the most destructive diseases of tomato (Solanum lycopersicum), and is caused by the seed-borne gram-positive bacterium Clavibacter michiganensis subsp. michiganensis (Cmm). This vascular pathogen generally invades and proliferates in the xylem through natural openings or wounds, causing wilt and canker symptoms. The incidence of symptomless latent infections and the invasion of tomato seeds by Cmm are widespread. Pathogenicity is mediated by virulence factors and transcriptional regulators encoded by the chromosome and two natural plasmids...
March 12, 2018: Molecular Plant Pathology
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"