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outer membrane protein and biofilm formation

Aidan J Taylor, Shadi A I Zakai, David J Kelly
The outer membrane (OM) of Gram-negative pathogenic bacteria is a key structure in host-pathogen interactions that contains a plethora of proteins, performing a range of functions including adhesion, nutrient uptake, export of effectors and interaction with innate and adaptive components of the immune system. In addition, the OM can exclude drugs and thus contribute to antimicrobial resistance. The OM of the food-borne pathogen Campylobacter jejuni contains porins, adhesins and other virulence factors that must be specifically localized to this membrane, but the protein sorting mechanisms involved are only partially understood...
2017: Frontiers in Microbiology
Sandro Roier, Franz G Zingl, Fatih Cakar, Stefan Schild
Outer membrane vesicle (OMV) release by Gram-negative bacteria has been observed and studied for decades. First considered as a by-product of cell lysis, it soon became evident that OMVs are actively secreted from the outer membrane (OM) of Gram-negative bacteria. Accordingly, these small particles (~ 10-300 nm in diameter) consist mainly of OM components like phospholipids (PLs), OM proteins, and lipopolysaccharides or lipooligosaccharides. However, OMVs may also comprise periplasmic, inner membrane, or cytoplasmic components...
May 10, 2016: Microbial Cell
Shakiba Darwish Alipour Astaneh, Iraj Rasooli, Seyed Latif Mousavi Gargari
Increased resistance and survival, as well as immune evasion, play a significant role in the pathogenicity of Acinetobacter baumannii. Here, we report on the adhesion of the bacterium to epithelial cells and formation of biofilm on abiotic surfaces. We identificed autotransporter (AT) genes that encode homologues (Fha-like) of the two-partner secretion system (TPS) in A.baumannii (ATCC19606) which we designate as FhaB (exoprotein) and FhaC (transporter) and demonstrate that these novel genes, are under the control of distinct regulatable promoters within either the same (FhaBC) or two distinct (FhaB and FhaC) cells...
March 1, 2017: Frontiers in Bioscience (Elite Edition)
Toan Phuoc Hong, Michelle Q Carter, Paolo Struffi, Stefano Casonato, Youai Hao, Joseph S Lam, Stephen Lory, Olivier Jousson
BACKGROUND: Pseudomonas aeruginosa pathogenicity island 1 (PAPI-1) is one of the largest genomic islands of this important opportunistic human pathogen. Previous studies have shown that PAPI-1 encodes several putative virulence factors, including a major regulator of biofilm formation and antibiotic-resistance traits. PAPI-1 is horizontally transferable into recipient strains lacking this island via conjugation mediated by the specialized type IV pilus. The PAPI-1 encodes a cluster of ten genes associated with the synthesis and assembly of the type IV pilus...
February 7, 2017: BMC Microbiology
Bruno P Lima, Wenyuan Shi, Renate Lux
To successfully colonize the oral cavity, bacteria must directly or indirectly adhere to available oral surfaces. Fusobacterium nucleatum plays an important role in oral biofilm community development due to its broad adherence abilities, serving as a bridge between members of the oral biofilm that cannot directly bind to each other. In our efforts to characterize the molecular mechanisms utilized by F. nucleatum to physically bind to key members of the oral community, we investigated the involvement of F. nucleatum outer membrane proteins in its ability to bind to the pioneer biofilm colonizer, Streptococcus gordonii...
February 7, 2017: MicrobiologyOpen
Loreine Agulló, María José Romero-Silva, Mirian Domenech, Michael Seeger
p-Cymene is an aromatic terpene that is present in diverse plant species. The aims of this study were to study the p-cymene metabolism in the model aromatic-degrading bacterium Burkholderia xenovorans LB400, and its response to p-cymene. The catabolic p-cymene (cym) and p-cumate (cmt) genes are clustered on the LB400 major chromosome. B. xenovorans LB400 was able to grow on p-cymene as well as on p-cumate as a sole carbon and energy sources. LB400 growth attained higher cell concentration at stationary phase on p-cumate than on p-cymene...
2017: PloS One
Hideo Yonezawa, Takako Osaki, Toshiyuki Fukutomi, Tomoko Hanawa, Satoshi Kurata, Cynthia Zaman, Fuhito Hojo, Shigeru Kamiya
Helicobacter pylori is one of the most common causes of bacterial infection in humans, and it forms biofilms on human gastric mucosal epithelium as well as on in vitro abiotic surfaces. Bacterial biofilm is critical not only for environmental survival but also for successful infection. We previously demonstrated that strain TK1402, which was isolated from a Japanese patient with duodenal and gastric ulcers, has high biofilm-forming ability in vitro relative to other strains. In addition, we showed that outer membrane vesicles (OMV) play an important role in biofilm formation...
March 15, 2017: Journal of Bacteriology
Liangyou Zhao, Xueli Gao, Chaonan Liu, Xiaoping Lv, Nan Jiang, Shimin Zheng
Haemophilus parasuis is an important pathogen causing severe infections in pigs. However, the specific bacterial factors that participate in pathogenic process are poorly understood. VacJ protein is a recently discovered outer membrane lipoprotein that relates to virulence in several pathogens. To characterize the function of the vacJ gene in H. parasuis virulent strain HS49, a vacJ gene-deletion mutant ΔvacJ and its complemented strain were constructed. Our findings supported that VacJ is essential for maintenance of cellular integrity and stress tolerance of H...
March 1, 2017: Gene
Anchanee Kubera, Arinthip Thamchaipenet, Menachem Shoham
Pasteurella multocida (Pm) is the causative agent of atrophic rhinitis in swine. This study aimed to discover biofilm inhibitors against swine Pm to counteract antibiotic resistance and decrease virulence. The virulence factor outer membrane protein A (OmpA) was targeted. A library of drugs approved by the Food and Drug Administration (FDA) was used to perform virtual screening against PmOmpA. The top-scoring compounds had no effect on the growth of Pm serotype A or D. Mycophenolate mofetil showed the highest efficacy in inhibiting biofilm formation by Pm serotype A, with an IC50 of 7...
January 2017: Biofouling
Eric Hong Jian Wong, Chow Goon Ng, Eng Guan Chua, Alfred Chin Yen Tay, Fanny Peters, Barry J Marshall, Bow Ho, Khean Lee Goh, Jamuna Vadivelu, Mun Fai Loke
BACKGROUND: Biofilm formation by Helicobacter pylori may be one of the factors influencing eradication outcome. However, genetic differences between good and poor biofilm forming strains have not been studied. MATERIALS AND METHODS: Biofilm yield of 32 Helicobacter pylori strains (standard strain and 31 clinical strains) were determined by crystal-violet assay and grouped into poor, moderate and good biofilm forming groups. Whole genome sequencing of these 32 clinical strains was performed on the Illumina MiSeq platform...
2016: PloS One
Adina R Bujold, Josée Labrie, Mario Jacques, Janet I MacInnes
Actinobacillus suis is an opportunistic pathogen that resides in the tonsils of the soft palate of swine. Unknown stimuli can cause this organism to invade the host, resulting in septicaemia and sequelae including death. To better understand its pathogenesis, the expression of several adhesin genes was evaluated by semi-quantitative real-time PCR in A. suis grown in conditions that mimic the host environment, including different nutrient and oxygen levels, exponential and stationary phases of growth, and in the presence of the stress hormone epinephrine...
November 15, 2016: Veterinary Microbiology
Martin Lappann, Andreas Otto, Madita Brauer, Dörte Becher, Ulrich Vogel, Kay Johswich
Neisseria meningitidis, the meningococcus, bears the potential to cause life-threatening invasive diseases, but it usually colonizes the nasopharynx without causing any symptoms. Within the nasopharynx, Neisseria meningitidis must face temperature changes depending on the ambient air temperature. Indeed, the nasopharyngeal temperature can be substantially lower than 37°C, the temperature commonly used in experimental settings. Here, we compared the levels of meningococcal biofilm formation, autoaggregation, and cellular adherence at 32°C and 37°C and found a clear increase in all these phenotypes at 32°C suggestive of a stronger in vivo colonization capability at this temperature...
December 2016: Infection and Immunity
Kathryn L Naylor, Magdalena Widziolek, Stuart Hunt, Mary Conolly, Matthew Hicks, Prachi Stafford, Jan Potempa, Craig Murdoch, C W Ian Douglas, Graham P Stafford
Outer membrane protein A (OmpA) is a key outer membrane protein found in Gram-negative bacteria that contributes to several crucial processes in bacterial virulence. In Porphyromonas gingivalis, OmpA is predicted as a heterotrimer of OmpA1 and OmpA2 subunits encoded by adjacent genes. Here we describe the role of OmpA and its individual subunits in the interaction of P. gingivalis with oral cells. Using knockout mutagenesis, we show that OmpA2 plays a significant role in biofilm formation and interaction with human epithelial cells...
February 2017: MicrobiologyOpen
Sarath Chandra Dantu, Sagar Khavnekar, Avinash Kale
Peb4 from Campylobacter jejuni is an intertwined dimeric, periplasmic holdase, which also exhibits peptidyl prolyl cis/trans isomerase (PPIase) activity. Peb4 gene deletion alters the outer membrane protein profile and impairs cellular adhesion and biofilm formation for C. jejuni. Earlier crystallographic study has proposed that the PPIase domains are flexible and might form a cradle for holding the substrate and these aspects of Peb4 were explored using sub-microsecond molecular dynamics simulations in solution environment...
July 19, 2016: Journal of Biomolecular Structure & Dynamics
Florencia A Ficarra, Carolina Grandellis, Estela M Galván, Luis Ielpi, Regina Feil, John E Lunn, Natalia Gottig, Jorgelina Ottado
Xanthomonas citri ssp. citri (Xcc) causes canker disease in citrus, and biofilm formation is critical for the disease cycle. OprB (Outer membrane protein B) has been shown previously to be more abundant in Xcc biofilms compared with the planktonic state. In this work, we showed that the loss of OprB in an oprB mutant abolishes bacterial biofilm formation and adherence to the host, and also compromises virulence and efficient epiphytic survival of the bacteria. Moreover, the oprB mutant is impaired in bacterial stress resistance...
June 2017: Molecular Plant Pathology
Luhua Zhang, Ying Li, Yiping Wen, Gee W Lau, Xiaobo Huang, Rui Wu, Qigui Yan, Yong Huang, Qin Zhao, Xiaoping Ma, Xintian Wen, Sanjie Cao
Haemophilus parasuis is an opportunistic pathogen that causes Glässer's disease in swine, with polyserositis, meningitis, and arthritis. The high-temperature requirement A (HtrA)-like protease, which is involved in protein quality control, has been reported to be a virulence factor in many pathogens. In this study, we showed that HtrA of H. parasuis (HpHtrA) exhibited both chaperone and protease activities. Finally, nickel import ATP-binding protein (NikE), periplasmic dipeptide transport protein (DppA), and outer membrane protein A (OmpA) were identified as proteolytic substrates for HpHtrA...
August 2016: Infection and Immunity
Tobias Dörr, Fernanda Delgado, Benjamin D Umans, Matthew A Gerding, Brigid M Davis, Matthew K Waldor
Gram-negative bacteria are notoriously resistant to a variety of high-molecular-weight antibiotics due to the limited permeability of their outer membrane (OM). The basis of OM barrier function and the genetic factors required for its maintenance remain incompletely understood. Here, we employed transposon insertion sequencing to identify genes required for Vibrio cholerae resistance to vancomycin and bacitracin, antibiotics that are thought to be too large to efficiently penetrate the OM. The screen yielded several genes whose protein products are predicted to participate in processes important for OM barrier functions and for biofilm formation...
August 2016: Antimicrobial Agents and Chemotherapy
Min Xu, Xuan Yang, Xiu-An Yang, Lei Zhou, Tie-Zheng Liu, Zusen Fan, Tao Jiang
YfiBNR is a recently identified bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) signaling system in opportunistic pathogens. It is a key regulator of biofilm formation, which is correlated with prolonged persistence of infection and antibiotic drug resistance. In response to cell stress, YfiB in the outer membrane can sequester the periplasmic protein YfiR, releasing its inhibition of YfiN on the inner membrane and thus provoking the diguanylate cyclase activity of YfiN to induce c-di-GMP production. However, the detailed regulatory mechanism remains elusive...
June 2016: Protein & Cell
Livia Pilatti, Jacqueline Boldrin de Paiva, Thaís Cabrera Galvão Rojas, Janaína Luisa Leite, Rogério Arcuri Conceição, Gerson Nakazato, Wanderley Dias da Silveira
BACKGROUND: Avian pathogenic Escherichia coli strains cause extraintestinal diseases in birds, leading to substantial economic losses to the poultry industry worldwide. Bacteria that invade cells can overcome the host humoral immune response, resulting in a higher pathogenicity potential. Invasins are members of a large family of outer membrane proteins that allow pathogen invasion into host cells by interacting with specific receptors on the cell surface. RESULTS: An in silico analysis of the genome of a septicemic APEC strain (SEPT362) demonstrated the presence of a putative invasin homologous to the ychO gene from E...
March 10, 2016: BMC Microbiology
Yan Wang, Archana Andole Pannuri, Dongchun Ni, Haizhen Zhou, Xiou Cao, Xiaomei Lu, Tony Romeo, Yihua Huang
The partially de-N-acetylated poly-β-1,6-N-acetyl-d-glucosamine (dPNAG) polymer serves as an intercellular biofilm adhesin that plays an essential role for the development and maintenance of integrity of biofilms of diverse bacterial species. Translocation of dPNAG across the bacterial outer membrane is mediated by a tetratricopeptide repeat-containing outer membrane protein, PgaA. To understand the molecular basis of dPNAG translocation, we determined the crystal structure of the C-terminal transmembrane domain of PgaA (residues 513-807)...
May 6, 2016: Journal of Biological Chemistry
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