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1578 records returned

The Tat pathway of plant pathogen Dickeya dadantii 3937 contributes to virulence and fitnessEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Protein secretion plays a very important role in the virulence of the bacterium Dickeya dadantii, the causative agent of soft rot disease, in a wide range of plant species. We studied the contribution of the twin-arginine translocation (Tat) protein system to the adaptation of D. dadantii 3937 to different growth conditions and to the interaction with the plant host. First, a list of 44 putative Tat substrates was obtained using bioinformatic programs taking advantage of the availability of the complete sequence of this bacterium. Second, a tatC mutant strain was constructed and analysed. The mutant displayed a pleiotropic...
Source: FEMS Microbiology Letters - November 20, 2009 Category: Microbiology Authors: Manuel Rodríguez-Sanz, María Antúnez-Lamas, Carlos Rojas, Emilia López-Solanilla, José M. Palacios, Pablo Rodríguez-Palenzuela, Luis Rey Source Type: journals

Analyses of binding sequences of the PhaR protein of Rhodobacter sphaeroides FJ1Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we determined that PhaR binds to an 11-bp palindromic sequence, 5'-CTGCN3GCAG-3', located at nucleotides [minus]69 to [minus]59 and [minus]97 to [minus]87 relative to the translation start site of phaP. Substitution of the three spacer nucleotides with any three or four nucleotides in this sequence had no effect on PhaR binding, but all other base deletions or substitutions in this sequence abolished its ability to bind PhaR both in vitro and in vivo. These results suggest that PhaR regulates the expression of phaP in R. sphaeroides FJ1. (Source: FEMS Microbiology Letters)
Source: FEMS Microbiology Letters - November 18, 2009 Category: Microbiology Authors: Min-En Chou, Mei-Kwei Yang Source Type: journals

Effect of cyclic bis(3'–5')diguanylic acid and its analogs on bacterial biofilm formationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cyclic bis(3'[ndash]5')diguanylic acid (cyclic-di-GMP) functions as a second messenger in diverse species of bacteria to trigger wide-ranging physiological changes. We measured cyclic-di-GMP and its structural analogs such as cyclic bis(3'[ndash]5')guanylic/adenylic acid (cyclic-GpAp), cyclic bis(3'[ndash]5')guanylic/inosinic acid (cyclic-GpIp) and monophosphorothioic acid of cyclic-di-GMP (cyclic-GpGps) for effects on the biofilm formation of Staphylococcus aureus and Pseudomonas aeruginosa. We constructed a knockout mutant of SA0701, which is a GGDEF motif protein relevant to diguanylate cyclase from S. aureus 2507. We c...
Source: FEMS Microbiology Letters - November 13, 2009 Category: Microbiology Authors: Yuka Ishihara, Mamoru Hyodo, Yoshihiro Hayakawa, Taichi Kamegaya, Keiko Yamada, Akira Okamoto, Tadao Hasegawa, Michio Ohta Source Type: journals

Potentiality of the cox1 gene in the taxonomic resolution of soil fungiEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We explored the potential of the cox1 gene in the species resolution of soil fungi and compared it with the nuclear internal transcribed spacer (ITS) and small subunit (SSU)-rDNA. Conserved primers allowing the amplification of the fungal cox1 gene were designed, and a total of 47 isolates of Zygomycota and Ascomycota were investigated. The analysis revealed a lack of introns in >90% of the isolates. Comparison of the species of each of the six studied genera showed high interspecific sequence polymorphisms. Indeed, the average of nucleotide variations (4.2[ndash]11%) according to the genus, due mainly to the nucleotide su...
Source: FEMS Microbiology Letters - November 11, 2009 Category: Microbiology Authors: Claire Molitor, Beatrice Inthavong, Lucile Sage, Roberto A. Geremia, Bello Mouhamadou Source Type: journals

The stress response protein Gls24 is induced by copper and interacts with the CopZ copper chaperone of Enterococcus hiraeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Intracellular copper routing in Enterococcus hirae is accomplished by the CopZ copper chaperone. Under copper stress, CopZ donates Cu+ to the CopY repressor, thereby releasing its bound zinc and abolishing repressor[ndash]DNA interaction. This in turn induces the expression of the cop operon, which encodes CopY and CopZ, in addition to two copper ATPases, CopA and CopB. To gain further insight into the function of CopZ, the yeast two-hybrid system was used to screen for proteins interacting with the copper chaperone. This led to the identification of Gls24, a member of a family of stress response proteins. Gls24 is part of...
Source: FEMS Microbiology Letters - November 10, 2009 Category: Microbiology Authors: Jivko V. Stoyanov, Stefano Mancini, Zen Huat Lu, Frédéric Mourlane, Kristian R. Poulsen, Reinhard Wimmer, Marc Solioz Source Type: journals

Deletion of the C-terminus of polynucleotide phosphorylase increases twitching motility, a virulence characteristic of the anaerobic bacterial pathogen Dichelobacter nodosusEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we compared PNPase activity in three virulent and four benign strains of D. nodosus and found that PNPase activity is lower in virulent strains. We disrupted the pnpA gene in three benign D. nodosus strains and two virulent strains and showed that deletion of the S1 domain of PNPase reduced catalytic activity. In all but one case, deletion of the PNPase S1 domain had no effect on the thermostability of extracellular proteases. However, this deletion resulted in an increase in twitching motility in benign, but not in virulent strains. Reconstruction of the pnpA gene in two mutant benign strains reduced twitch...
Source: FEMS Microbiology Letters - November 7, 2009 Category: Microbiology Authors: Suresh K.A. Palanisamy, Carrie Fletcher, Livia Tanjung, Margaret E. Katz, Brian F. Cheetham Source Type: journals

Identification of first exfoliative toxin in Staphylococcus pseudintermediusEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Staphylococcus aureus, Staphylococcus hyicus, and Staphylococcus chromogenes are known to cause skin infections in human or animals by producing exfoliative toxins (ETs). Staphylococcus pseudintermedius can also cause canine pyoderma, but no exfoliative toxins or similar toxins have been reported. PCR with degenerate primers targeted to the conserved regions in ETA, ETB, and ETD from S. aureus and SHETB from S. hyicus, and subsequent chromosome walking identified a novel gene, designated as exi (exfoliative toxin of pseudintermedius) in S. pseudintermedius. EXI had significant homologies with the exfoliative toxins (43[nda...
Source: FEMS Microbiology Letters - November 6, 2009 Category: Microbiology Authors: Keiko Futagawa-Saito, Shinichiroh Makino, Fujiko Sunaga, Yukio Kato, Naomi Sakurai-Komada, William Ba-Thein, Tsuguaki Fukuyasu Source Type: journals

Enteroinvasive Escherichia coli vs. Shigella flexneri : how different patterns of gene expression affect virulenceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Important features of the enteroinvasive Escherichia coli (EIEC) phenotype and gene expression likely to confer EIEC with a lower ability to cause disease than Shigella flexneri were described here for the first time. To confirm the lower pathogenicity of EIEC, we have analyzed the keratoconjunctivitis developed in guinea-pigs with EIEC or S. flexneri. Shigella flexneri induced a more pronounced proinflammatory response, whereas EIEC induced a mild form of the disease. EIEC showed a significantly less efficient cell-to-cell Caco-2 dissemination when compared with S. flexneri. Plaques formed by EIEC during intercellular spr...
Source: FEMS Microbiology Letters - November 5, 2009 Category: Microbiology Authors: Ana Carolina Ramos Moreno, Lucas Gonçalves Ferreira, Marina Baquerizo Martinez Source Type: journals

tmRNA – a novel high-copy-number RNA diagnostic target – its application for Staphylococcus aureus detection using real-time NASBAEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A real-time nucleic acid sequence-based amplification assay, targeting tmRNA, was designed for the rapid identification of Staphylococcus aureus. The selectivity of the assay was confirmed against a panel of 76 Staphylococcus strains and species and 22 other bacterial species. A detection limit of 1 cell equivalent was determined for the assay. A chimeric in vitro transcribed internal amplification control was developed and included in the assay. Application of the assay in natural and artificially contaminated unpasteurized (raw) milk enabled detection of 1[ndash]10 CFUS. aureus mL[minus]1 in 3[ndash]4 h, without the need...
Source: FEMS Microbiology Letters - November 3, 2009 Category: Microbiology Authors: Justin O'Grady, Katrina Lacey, Barry Glynn, Terry J. Smith, Thomas Barry, Majella Maher Source Type: journals

Virulence analysis and gene expression profiling of the pigment-deficient mutant of Xanthomonas oryzae pathovar oryzaeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Xanthomonas oryzae pathovar oryzae (Xoo) causes bacterial blight disease in rice (Oryza sativa L.). For a study of function, we constructed a random insertion mutant library of Xoo using a Tn5 transposon and isolated the mutant strain (M11; aroK∷Tn5) that had extremely low pigment production. In addition, M11 had decreased virulence against the susceptible rice cultivar IR24. Thermal asymmetric interlaced-PCR and sequence analysis of M11 revealed that the transposon was inserted into the aroK gene (which encodes a shikimate kinase). To investigate the expression patterns of the pigment- and virulence-deficient mutan...
Source: FEMS Microbiology Letters - November 2, 2009 Category: Microbiology Authors: Young-Jin Park, Eun-Sung Song, Tae-Hwan Noh, Hyungtae Kim, Kap-Seok Yang, Jang-Ho Hahn, Hee-Wan Kang, Byoung-Moo Lee Source Type: journals

Fast DNA-based identification of the black truffle Tuber melanosporum with direct PCR and species-specific primersEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A quick and sensitive DNA-based assay for identifying the black truffle species Tuber melanosporum is presented. Both direct PCR and species-specific primers are used to amplify a phylogenetically informative region of T. melanosporum rDNA. This method was successfully used to screen fresh and frozen T. melanosporum fruitbodies, and could be modified for the molecular detection of other truffle and mushroom species. (Source: FEMS Microbiology Letters)
Source: FEMS Microbiology Letters - October 30, 2009 Category: Microbiology Authors: Gregory Bonito Source Type: journals

The ToxT-dependent methyl-accepting chemoreceptors AcfB and TcpI contribute to Vibrio cholerae intestinal colonizationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Vibrio cholerae colonizes the human intestine and causes the acute diarrheal disease cholera. Flagellar-mediated chemotaxis contributes to intestinal colonization as well as infectivity. The virulence-regulatory protein ToxT activates transcription of the genes encoding the major virulence factors cholera toxin and toxin coregulated pilus. ToxT additionally activates transcription of two genes, tcpI and acfB, located within the Vibrio Pathogenicity Island predicted to encode methyl-accepting chemoreceptors. We show that disruption of either tcpI or acfB individually does not noticeably affect V. cholerae intestinal coloniz...
Source: FEMS Microbiology Letters - October 28, 2009 Category: Microbiology Authors: Adriana Paola Chaparro, Syed Khalid Ali, Karl E. Klose Source Type: journals

The PhoB regulatory system modulates biofilm formation and stress response in El Tor biotype Vibrio choleraeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The PhoBR regulatory system is required for the induction of multiple genes under conditions of phosphate limitation. Here, we examine the role of PhoB in biofilm formation and environmental stress response in Vibrio cholerae of the El Tor biotype. Deletion of phoB or hapR enhanced biofilm formation in a phosphate-limited medium. Planktonic and redispersed biofilm cells of the [Delta]phoB mutant did not differ from wild type for the expression of HapR, suggesting that PhoB negatively affects biofilm formation through an HapR-independent pathway. The [Delta]phoB mutant exhibited elevated expression of exopolysaccharide gene...
Source: FEMS Microbiology Letters - October 28, 2009 Category: Microbiology Authors: Syed Zafar Sultan, Anisia J. Silva, Jorge A. Benitez Source Type: journals

Temporal variation of magnetotactic bacterial communities in two freshwater sediment microcosmsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Magnetotactic bacteria (MTB), which can mineralize nanosized magnetite or greigite crystals within cells, play important roles in biogeochemical processes, for example iron and sulfur cycling, and depositional remanent magnetization acquisitions. Despite decades of research, the knowledge of MTB distribution and ecology is still limited. In the present study, we investigated the temporal variation of MTB communities in freshwater sediment microcosms based on 16S rRNA genes and unifrac analyses. Two microcosms (MY8 and MY11) collected from two separate sites in Lake Miyun (Beijing, China) were analyzed. The majority of retr...
Source: FEMS Microbiology Letters - October 28, 2009 Category: Microbiology Authors: Wei Lin, Yongxin Pan Source Type: journals

FabH selectivity for anteiso branched-chain fatty acid precursors in low-temperature adaptation in Listeria monocytogenesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Gram-positive bacteria, including Listeria monocytogenes, adjust membrane fluidity by shortening the fatty acid chain length and increasing the proportional production of anteiso fatty acids at lower growth temperatures. The first condensation reaction in fatty acid biosynthesis is carried out by [beta]-ketoacyl-acyl carrier protein synthase III (FabH), which determines the type of fatty acid produced in bacteria. Here, we measured the initial rates of FabH-catalyzed condensation of malonyl-acyl carrier protein and alternate branched-chain precursor acyl-CoAs utilizing affinity-purified His-tagged L. monocytogenes FabH het...
Source: FEMS Microbiology Letters - October 27, 2009 Category: Microbiology Authors: Atul K. Singh, Yong-Mei Zhang, Kun Zhu, Chitra Subramanian, Zhong Li, Radheshyam K. Jayaswal, Craig Gatto, Charles O. Rock, Brian J. Wilkinson Source Type: journals

Expression of Escherichia coli Min system in Bacillus subtilis and its effect on cell divisionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In both rod-shaped Bacillus subtilis and Escherichia coli cells, Min proteins are involved in the regulation of division septa formation. In E. coli, dynamic oscillation of MinCD inhibitory complex and MinE, a topological specificity protein, prevents improper polar septation. However, in B. subtilis no MinE is present and no oscillation of Min proteins can be observed. The function of MinE is substituted by that of an unrelated DivIVA protein, which targets MinCD to division sites and retains them at the cell poles. We inspected cell division when the E. coli Min system was introduced into B. subtilis cells. Expression of...
Source: FEMS Microbiology Letters - October 23, 2009 Category: Microbiology Authors: Nad'a Pavlendová, Katarína Muchová, Imrich Barák Source Type: journals

Analysis of the mucR gene regulating biosynthesis of exopolysaccharides: implications for biofilm formation in Sinorhizobium meliloti Rm1021Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Bacterial surface polysaccharides are crucial for establishment of successful rhizobia[ndash]legume symbiosis, and in most bacteria, are also critical for biofilm formation and surface colonization. In Sinorhizobium meliloti, the regulatory protein MucR controls exopolysaccharide production. To clarify the relationship between exopolysaccharide synthesis and biofilm formation, we studied mucR expression under growth conditions that influence attachment to polyvinylchloride, developed a microtiter plate assay to quantify biofilm formation in S. meliloti strain Rm1021 and mutants defective in succinoglycan (EPS I) and/or gal...
Source: FEMS Microbiology Letters - October 22, 2009 Category: Microbiology Authors: Luciana V. Rinaudi, Fernando Sorroche, Ángeles Zorreguieta, Walter Giordano Source Type: journals

Phenotypic and genetic characterizations of Streptococcus dysgalactiae strains isolated from fish collected in Japan and other Asian countriesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Lancefield group C Streptococcus dysgalactiae is an emerging fish pathogen, which was first isolated in 2002 in Japan. Streptococcus dysgalactiae isolates collected from diseased fish in Japan (n=12), Taiwan (n=12), China (n=2), Malaysia (n=3), and Indonesia (n=1) were characterized using biased sinusoidal field gel electrophoresis (BSFGE), sodA gene sequence analysis, and antimicrobial susceptibility. These isolates exhibited high phenotypic homogeneity irrespective of the countries from where the strains were collected. Seventeen isolates were found to be resistant to oxytetracycline and carried the tet(M) gene, except f...
Source: FEMS Microbiology Letters - October 22, 2009 Category: Microbiology Authors: Mohamed Abdelsalam, Shih-Chu Chen, Terutoyo Yoshida Source Type: journals

Rapid cloning, identification, and application of one novel crystal protein gene cry30Fa1 from Bacillus thuringiensisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, a fast and efficient strategy has been developed for identifying and isolating novel cry genes from Bacillus thuringiensis by combining the PCR-restriction fragment length polymorphism and the single-oligonucleotide nested-PCR method. Using this method, one novel holotype cry gene, cry30Fa1, encoding a polypeptide of 687 amino acid residues with a molecular mass of 77.1 kDa, 74% identical to Cry30Aa1, was cloned from the B. thuringiensis strain BtMC28. Furthermore, the cry30Fa1 gene was successfully expressed in Escherichia coli BL21 (DE3). The Cry30Fa1 proteins, isolated from the cultures of recombinant E. ...
Source: FEMS Microbiology Letters - October 22, 2009 Category: Microbiology Authors: Furong Tan, Aiping Zheng, Jun Zhu, Lingxia Wang, Shuangcheng Li, Qiming Deng, Shiquan Wang, Ping Li, Xueming Tang Source Type: journals

Recombinant expression and redox properties of triheme c membrane-bound quinol peroxidaseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The qpo gene of Aggregatibacter actinomycetemcomitans encodes a triheme c-containing membrane-bound enzyme, quinol peroxidase (QPO) that catalyzes peroxidation reaction in the respiratory chain and uses quinol as the physiological electron donor. The QPO of A. actinomycetemcomitans is the only characterized QPO, but homologues of the qpo gene are widely distributed among many gram-negative bacteria, including Haemophils ducreii, Bacteroides fragilis, and Escherichia coli. One-third of the amino acid sequence of QPO from the N-terminal end is unique, whereas two-thirds of the sequence from the C-terminal end exhibits high h...
Source: FEMS Microbiology Letters - October 22, 2009 Category: Microbiology Authors: Eizo Takashima, Hiroyuki Yamada, Tetsuo Yamashita, Kazunobu Matsushita, Kiyoshi Konishi Source Type: journals

Disruption of cagA, the apoprotein gene of chromoprotein antibiotic C-1027, eliminates holo-antibiotic production, but not the cytotoxic chromophoreEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
C-1027 is a chromoprotein of the nine-membered enediyne antitumour antibiotic family, comprising apoprotein to stabilize and transport the enediyne chromophore. The disruption of apoprotein gene cagA within the C-1027 biosynthetic gene cluster abolished C-1027 holo-antibiotic production detected by an antibacterial assay, as well as the expression of the apoprotein and C-1027 chromophore extracted following protein precipitation of the culture supernatant. Complementation of the cagA-disrupted mutant AKO with the intact cagA gene restored C-1027 production, suggesting that cagA is indispensable for holo-antibiotic producti...
Source: FEMS Microbiology Letters - October 21, 2009 Category: Microbiology Authors: Zhihui Cui, Lifei Wang, Songmei Wang, Guangwei Li, Bin Hong Source Type: journals

A physiologically significant role in nitrite reduction of the CcoP subunit of the cytochrome oxidase cbb3 from Neisseria gonorrhoeaeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The CcoP subunit of cytochrome oxidase cbb3 of Neisseria gonorrhoeae is predicted to include a C-terminal extension in which there is a C-A-A-C-H- motif typical of heme attachment sites in c-type cytochromes. Substitutions of key cysteine and histidine residues of this motif resulted in mutants that grew normally in oxygen-sufficient cultures and reduced oxygen at the same rate as the parent strain. In contrast, after oxygen-limited growth in the presence of nitrite, rates of nitrite reduction were significantly lower than those of the parent, consistent with a role for this third heme-binding domain in electron transfer t...
Source: FEMS Microbiology Letters - October 21, 2009 Category: Microbiology Authors: Amanda Hopper, Nicholas Tovell, Jeffrey Cole Source Type: journals

Identification of Salmonella enterica subspecies I, Salmonella enterica serovars Typhimurium, Enteritidis and Typhi using multiplex PCREmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study was designed to develop a multiplex PCR method with five specific primer pairs for the detection of Salmonella spp., Salmonella subspecies I, Salmonella enterica serovars Typhimurium, Typhi and Enteritidis. A multiplex PCR was constructed with five primer pairs for the detection of Salmonella and pathogenic Salmonella serovars, including a specific primer pair for Salmonella Typhi, based on the sequence comparison between genomic DNA sequences of 12 Salmonella strains. Each primer pair was specifically targeted to Salmonella spp., Salmonella subspecies I, Salmonella Typhimurium, Typhi and Enteritidis. This multi...
Source: FEMS Microbiology Letters - October 16, 2009 Category: Microbiology Authors: Si Hong Park, Hyun Joong Kim, Woo Hee Cho, Jae Hwan Kim, Mi Hwa Oh, Sung Hun Kim, Bok Kwon Lee, Steven C. Ricke, Hae Yeong Kim Source Type: journals

The synergistic activity of triclosan and ciprofloxacin on biofilms of Salmonella TyphimuriumEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Triclosan is a biocide whose wide use has raised a debate about the potential benefits vs. hazards of the incorporation of antimicrobials in consumer products. The purpose of the present study was to determine whether exposure of biofilms of Salmonella enterica serovar Typhimurium to triclosan influences the tolerance of the bacteria towards antibiotics such as ciprofloxacin and vice versa. A synergistic antibiofilm activity was observed when the biofilms were treated with triclosan before or together with ciprofloxacin, and an additive activity was observed with planktonic cells. For example 500 [mu]g mL[minus]1 triclosan...
Source: FEMS Microbiology Letters - October 15, 2009 Category: Microbiology Authors: Mina Tabak, Keren Scher, Michael L. Chikindas, Sima Yaron Source Type: journals

Pseudomonas aeruginosa PA14 cupD transcription is activated by the RcsB response regulator, but repressed by its putative cognate sensor RcsCEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The opportunistic pathogen Pseudomonas aeruginosa PA14 possesses four fimbrial cup clusters, which may confer the ability to adapt to different environments. cupD lies in the pathogenicity island PAPI-1 next to genes coding for a putative phosphorelay system composed of the hybrid histidine kinase RcsC and the response regulator RcsB. The main focus of this work was the regulation of cupD at the mRNA level. It was found that the HN-S-like protein MvaT does not exert a strong influence on cupD transcript levels, as it does for cupA. cupD transcription is higher in cultures grown at 28 °C, which agrees with a cupD mutant pr...
Source: FEMS Microbiology Letters - October 14, 2009 Category: Microbiology Authors: Gianlucca G. Nicastro, Ana Laura Boechat, Cecília M. Abe, Gilberto H. Kaihami, Regina L. Baldini Source Type: journals

Serum resistance of Acinetobacter baumannii through the binding of factor H to outer membrane proteinsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Bacteremia is a common systemic disease caused by Acinetobacter baumannii, an important hospital-acquired pathogen among critically ill patients. The complement system is central to innate immune defense against invading bacteria in the blood. The present study investigated the susceptibility of clinical A. baumannii isolates to normal human sera (NHS), and determined the resistance mechanism of A. baumannii against complement-mediated lysis. The survival of A. baumannii isolates from bacteremic patients was significantly decreased in undiluted NHS, but they were resistant to 40% NHS. The alternative complement pathway was...
Source: FEMS Microbiology Letters - October 13, 2009 Category: Microbiology Authors: Sang Woo Kim, Chul Hee Choi, Dong Chan Moon, Jong Sook Jin, Jung Hwa Lee, Ji-Hyun Shin, Jung Min Kim, Yoo Chul Lee, Sung Yong Seol, Dong Taek Cho, Je Chul Lee Source Type: journals

SdrI of Staphylococcus saprophyticus is a multifunctional protein: localization of the fibronectin-binding siteEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Staphylococcus saprophyticus, an important cause of urinary tract infections in young women, expresses the surface protein SdrI, a member of the serine-aspartate repeat (SD) protein family. Here we analyse the fibronectin-binding ability of SdrI, as S. saprophyticus is known to bind fibronectin and there is no known SD protein with this function. This protein does not contain the binding motif typical for fibronectin-binding proteins. Using recombinant fragments of SdrI, we localized the binding domain in the A region and show that SdrI bound to the N-terminal 30-kDa fragment of fibronectin. The fibronectin-binding functio...
Source: FEMS Microbiology Letters - October 12, 2009 Category: Microbiology Authors: Türkân Sak[iota]nç, Britta Kleine, Nadine Michalski, Martin Kaase, Sören G. Gatermann Source Type: journals

Use of isothermal microcalorimetry to monitor microbial activitiesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Isothermal calorimetry measures the heat flow of biological processes, which is proportional to the rate at which a given chemical or physical process takes place. Modern isothermal microcalorimeters make measurements of less than a microwatt of heat flow possible. As a result, as few as 10 000[ndash]100 000 active bacterial cells in culture are sufficient to produce a real-time signal dynamically related to the number of cells present and their activity. Specimens containing bacteria need little preparation, and isothermal microcalorimetry (IMC) is a nondestructive method. After IMC measurements, the undisturbed samples c...
Source: FEMS Microbiology Letters - October 12, 2009 Category: Microbiology Authors: Olivier Braissant, Dieter Wirz, Beat Göpfert, Alma U. Daniels Source Type: journals

A cytosolic phospholipase A2-like protein in the filamentous fungus Aspergillus oryzae localizes to the intramembrane space of the mitochondriaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we characterize the putative cPLA2-like protein, AoPlaA, in the filamentous fungus Aspergillus oryzae. When AoPlaA-EGFP was expressed in A. oryzae, it localized to the tubular structures that was costained by the marker dye for the mitochondria. A biochemical fractionation experiment showed that AoPlaA was present in the mitochondria-enriched fraction. The presence of an N-terminal cleavable mitochondrial targeting signal in AoPlaA was demonstrated by N-terminal amino acid sequence analysis, and by showing that chimeric proteins consisting of N-terminal 65 or 50 amino acids of AoPlaA fused to enhanced green ...
Source: FEMS Microbiology Letters - October 10, 2009 Category: Microbiology Authors: Kohei Takaya, Yujiro Higuchi, Katsuhiko Kitamoto, Manabu Arioka Source Type: journals

Involvement of MmoR and MmoG in the transcriptional activation of soluble methane monooxygenase genes in Methylosinus trichosporium OB3bEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Methanotrophs oxidize methane to methanol using the enzyme methane monooxygenase. Methylosinus trichosporium OB3b has two such enzymes: a membrane-bound particulate methane monooxygenase (pMMO) and a soluble, cytoplasmic methane monooxygenase (sMMO). In methanotrophs possessing both enzymes, the expression of the genes encoding sMMO and pMMO is regulated by copper ions, with sMMO expressed solely when copper is limiting. Virtually nothing is known about the specific machinery involved in the copper-regulated transcription of mmo genes except the identification of two proteins necessary for the expression: a [sigma]54-depen...
Source: FEMS Microbiology Letters - October 10, 2009 Category: Microbiology Authors: Julie Scanlan, Marc G. Dumont, J. Colin Murrell Source Type: journals

Contribution of the RsaL global regulator to Pseudomonas aeruginosa virulence and biofilm formationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In Pseudomonas aeruginosa, acyl-homoserine-lactone quorum sensing (acyl-HSL QS) regulates the expression of virulence factors and biofilm formation in response to cell density. The RsaL protein represses transcription of the lasI gene, encoding the 3OC12-HSL signal synthase. The level of 3OC12-HSL is 10-fold higher in an rsaL mutant than in the wild type. In this work, we studied the effect of 3OC12-HSL overproduction caused by the rsaL mutation by comparing the transcriptional profiles and virulence-related phenotypes of a P. aeruginosa rsaL mutant and its wild-type parent. Results showed that the rsaL mutant overproduces...
Source: FEMS Microbiology Letters - October 10, 2009 Category: Microbiology Authors: Giordano Rampioni, Martin Schuster, Everett Peter Greenberg, Elisabetta Zennaro, Livia Leoni Source Type: journals

Characterization of SgcE6, the flavin reductase component supporting FAD-dependent halogenation and hydroxylation in the biosynthesis of the enediyne antitumor antibiotic C-1027Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The C-1027 enediyne antitumor antibiotic from Streptomyces globisporus possesses an (S)-3-chloro-5-hydroxy-[beta]-tyrosine moiety, the chloro- and hydroxy-substituents of which are installed by a flavin-dependent halogenase SgcC3 and monooxygenase SgcC, respectively. Interestingly, a single flavin reductase, SgcE6, can provide reduced flavin to both enzymes. Bioinformatics analysis reveals that, similar to other flavin reductases involved in natural product biosynthesis, SgcE6 belongs to the HpaC-like subfamily of the Class I flavin reductases. The present study describes the steady-state kinetic characterization of SgcE6 ...
Source: FEMS Microbiology Letters - October 8, 2009 Category: Microbiology Authors: Steven G. Van Lanen, Shuangjun Lin, Geoff P. Horsman, Ben Shen Source Type: journals

Programmed cell death and the pathogenesis of tissue injury induced by type A Francisella tularensisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Francisella tularensis is a highly virulent bacterial species that causes various forms of tularemia in humans. The urgency in understanding the pathogenesis of these diseases has stimulated unprecedented interest in this bacterial species over the past few years. Recent findings underscore a number of important distinctions between the Francisella ssp. and emphasize the importance of using type A F. tularensis strains when characterizing pathophysiological responses that are relevant to the lethal forms of human disease. This review focuses on the mediators of cell death induction in infected tissues and the implications ...
Source: FEMS Microbiology Letters - October 7, 2009 Category: Microbiology Authors: Michael J. Parmely, Jeffrey L. Fischer, David M. Pinson Source Type: journals

The metal efflux island of Legionella pneumophila is not required for survival in macrophages and amoebasEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Legionella pneumophila is an intracellular pathogen causing pneumonia-like disease in humans. A 43-kb putative heavy metal efflux gene island was found on the L. pneumophila genome. Large Legionella deletion strains of the metal efflux genes were tested in human THP-1-derived macrophages and amoebal Acanthamoeba castellanii cells and were able to survive and replicate similar to the wild type, suggesting that they do not play a significant role within the intracellular environment. Examination of the sequence of this genomic island revealed that some genes were not accurately annotated and there were no known metal-respons...
Source: FEMS Microbiology Letters - October 7, 2009 Category: Microbiology Authors: Eun-Hae Kim, Xavier Charpentier, Oscar Torres-Urquidy, Megan M. McEvoy, Christopher Rensing Source Type: journals

Cell-surface phytase on Pichia pastoris cell wall offers great potential as a feed supplementEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cell-surface expression of phytase allows the enzyme to be expressed and anchored on the cell surface of Pichia pastoris. This avoids tedious downstream processes such as purification and separation involved with extracellular expression. In addition, yeast cells with anchored proteins can be used as a whole-cell biocatalyst with high value added. In this work, the phytase was expressed on the cell surface of P. pastoris with a glycosylphosphatidylinositol anchoring system. The recombinant phytase was shown to be located at the cell surface. The cell-surface phytase exhibited high activity with an optimal temperature at 50...
Source: FEMS Microbiology Letters - October 5, 2009 Category: Microbiology Authors: Piyanun Harnpicharnchai, Warasirin Sornlake, Kittapong Tang, Lily Eurwilaichitr, Sutipa Tanapongpipat Source Type: journals

Pythium burgundicum sp. nov. isolated from soil samples taken in French vineyardsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
During the course of investigation on pythiaceous fungi occurring in the Burgundian vineyards, a new species of Pythium has been isolated. This oomycete is characterized by its nonproliferating and nonsporulating, spherical to cylindrical type of sporangia (hyphal bodies) germinating through germ tubes, smooth-walled oogonia that are supplied with hypogynous, monoclinous or rarely diclinous antheridia, and smooth-walled oospores. The antheridial cells are very prominent and are reminiscent of Pythium bifurcatum, Pythium segnitium and Pythium longandrum described previously by the author. The internal transcribed spacer reg...
Source: FEMS Microbiology Letters - October 5, 2009 Category: Microbiology Authors: Bernard Paul Source Type: journals

Effector gene screening allows unambiguous identification of Fusarium oxysporum f. sp. lycopersici races and discrimination from other formae specialesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, a large, worldwide collection of F. oxysporum isolates was screened for the presence of seven SIX genes (SIX1[ndash]SIX7). The results convincingly show that identification of F. oxysporum formae speciales and races based on host-specific virulence genes can be very robust. SIX1, SIX2, SIX3 and SIX5 can be used for unambiguous identification of the forma specialis lycopersici. In addition, SIX4 can be used for the identification of race 1 strains, while polymorphisms in SIX3 can be exploited to differentiate race 2 from race 3 strains. For SIX6 and SIX7, close homologs were found in a few other formae specia...
Source: FEMS Microbiology Letters - October 2, 2009 Category: Microbiology Authors: Bart Lievens, Petra M. Houterman, Martijn Rep Source Type: journals

Adherence to host extracellular matrix and serum components by Enterococcus faecium isolates of diverse originEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Enterococcus faecium has emerged as an important cause of nosocomial infections over the last two decades. We recently demonstrated collagen type I (CI) as a common adherence target for some E. faecium isolates and a significant correlation was found to exist between acm-mediated CI adherence and clinical origin. Here, we evaluated 60 diverse E. faecium isolates for their adherence to up to 15 immobilized host extracellular matrix and serum components. Adherence phenotypes were most commonly observed to fibronectin (Fn) (20% of the 60 isolates), fibrinogen (17%) and laminin (Ln) (13%), while only one or two of the isolates...
Source: FEMS Microbiology Letters - September 30, 2009 Category: Microbiology Authors: Meng Zhao, Jouko Sillanpää, Sreedhar R. Nallapareddy, Barbara E. Murray Source Type: journals

Steroids mediate resistance to the bactericidal effect of phosphatidylcholines against Helicobacter pyloriEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we have found that phosphatidylcholine carrying a linoleic acid molecule or arachidonic acid molecule has the potential to kill steroid-free H. pylori. The bactericidal action of phosphatidylcholines against H. pylori was due to the lytic activity of the phosphatidylcholines themselves and not due to the lytic activity of the unsaturated fatty acids or lyso-phosphatidylcholine resulting from the hydrolysis of the phosphatidylcholines. In contrast to the steroid-free H. pylori, the organism that absorbed and glucosylated free cholesterol was unaffected by the bactericidal action of the phosphatidylcholines. S...
Source: FEMS Microbiology Letters - September 30, 2009 Category: Microbiology Authors: Hirofumi Shimomura, Kouichi Hosoda, Shunji Hayashi, Kenji Yokota, Keiji Oguma, Yoshikazu Hirai Source Type: journals

Cellulosic alcoholic fermentation using recombinant Saccharomyces cerevisiae engineered for the production of Clostridium cellulovorans endoglucanase and Saccharomycopsis fibuligeraβ-glucosidaseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, we have demonstrated the construction of a yeast strain capable of conversion of a cellulosic substrate to ethanol, representing significant progress towards the realization of processing of cellulosic biomass in a consolidated bioprocessing configuration. (Source: FEMS Microbiology Letters)
Source: FEMS Microbiology Letters - September 30, 2009 Category: Microbiology Authors: Eugene Jeon, Jeong eun Hyeon, Lee Sung Eun, Byeoung-Soo Park, Seung Woo Kim, Jinwon Lee, Sung Ok Han Source Type: journals

Physiological role of NahW, the additional salicylate hydroxylase found in Pseudomonas stutzeri AN10Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The physiological role of NahW, the second salicylate hydroxylase of Pseudomonas stutzeri AN10, has been analysed by gene mutation and further complementation. When grown on naphthalene as a unique carbon and energy source, the nahW mutant showed a strong decrease in salicylate hydroxylase activity when compared with the wild-type strain, exhibited lower specific growth rates and accumulated salicylate in culture supernatants. Similarly, lower specific growth rates and salicylate accumulation were observed for the nahW mutant when growth on naphthalene supplemented with succinate or pyruvate. When P. stutzeri AN10 was grow...
Source: FEMS Microbiology Letters - September 30, 2009 Category: Microbiology Authors: Mariana P. Lanfranconi, Joseph A. Christie-Oleza, Cèlia Martín-Cardona, Lady Y. Suárez-Suárez, Jorge Lalucat, Balbina Nogales, Rafael Bosch Source Type: journals

Yeast as a tool for characterizing mono-ADP-ribosyltransferase toxinsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The emergence of bacterial antibiotic resistance poses a significant challenge in the pursuit of novel therapeutics, making new strategies for drug discovery imperative. We have developed a yeast growth-defect phenotypic screen to help solve this current dilemma. This approach facilitates the identification and characterization of a new diphtheria toxin (DT) group, ADP-ribosyltransferase toxins from pathogenic bacteria. In addition, this assay utilizes Saccharomyces cerevisiae, a reliable model for bacterial toxin expression, to streamline the identification and characterization of new inhibitors against this group of bact...
Source: FEMS Microbiology Letters - September 28, 2009 Category: Microbiology Authors: Zachari Turgeon, Dawn White, René Jørgensen, Danielle Visschedyk, Robert J. Fieldhouse, Dev Mangroo, A. Rod Merrill Source Type: journals

The Ile13 residue of microcin J25 is essential for recognition by the receptor FhuA, but not by the inner membrane transporter SbmAEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Entry of the peptide antibiotic microcin J25 (MccJ25) into target cells is mediated by the outer membrane receptor FhuA and the inner membrane protein SbmA. The latter also transports MccB17 into the cell cytoplasm. Comparison of MccJ25 and MccB17 revealed a tetrapeptide sequence (VGIG) common to both antibiotics. We speculated that this structural feature in MccJ25 could be a motif recognized by SbmA. To test this hypothesis, we used a MccJ25 variant in which the isoleucine in VGIG (position 13 in the MccJ25 sequence) was replaced by lysine (I13K). In experiments in which the FhuA receptor was bypassed, the substituted mi...
Source: FEMS Microbiology Letters - September 24, 2009 Category: Microbiology Authors: Sergio B. Socias, Konstantin Severinov, Raul A. Salomon Source Type: journals

Molecular analysis of Leptospira spp. isolated from humans by restriction fragment length polymorphism, real-time PCR and pulsed-field gel electrophoresisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A total of 17 Leptospira clinical strains isolated from humans in Croatia were serologically and genetically analysed. For serovar identification, the microscopic agglutination test (MAT) and pulsed-field gel electrophoresis (PFGE) were used. To identify isolates on genomic species level, PCR-based restriction fragment length polymorphism (RFLP) and real-time PCR were performed. MAT revealed the following serogroup affinities: Grippotyphosa (seven isolates), Icterohaemorrhagiae (eight isolates) and Javanica (two isolates). RFLP of PCR products from a 331-bp-long fragment of rrs (16S rRNA gene) digested with endonucleases M...
Source: FEMS Microbiology Letters - September 24, 2009 Category: Microbiology Authors: Nenad Turk, Zoran Milas, Vesna Mojcec, Eva Ruzic-Sabljic, Vilim Staresina, Zrinka Stritof, Josipa Habus, Daniele Postic Source Type: journals

Pseudomonas fluorescens CHA0 can kill subterranean termite Odontotermes obesus by inhibiting cytochrome c oxidase of the termite respiratory chainEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we show that cyanide of bacterial origin may inhibit cytochrome c oxidase (CCO) of the termite respiratory chain and demonstrate that HCN-producing bacteria such as P. fluorescens can actually kill a macroscopic insect pest by cyanide poisoning. This ability of pseudomonad metabolites such as cyanide, which can bring about pest death by blocking respiration through inhibition of CCO rather than infection or predation, can potentially overcome the behavioural adaptations of social insect pests such as termites and represents an attractive option for insect pest management. (Source: FEMS Microbiology Letters)
Source: FEMS Microbiology Letters - September 23, 2009 Category: Microbiology Authors: Karunanidhi Kanchana Devi, David Kothamasi Source Type: journals

Identification of a new promoter for the response regulator rcsB expression in Salmonella enterica serovar TyphimuriumEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The RcsCDB (Rcs) phosphorelay system regulates capsule synthesis, flagella production and other cellular activities in several enteric bacteria. This system consists of three proteins: the sensor RcsC, the cognate response regulator RcsB and the histidine-containing phosphotransfer protein RcsD (YojN), which is hypothesized to act as an intermediary in the phosphotransfer from RcsC to RcsB. The rcsC gene is convergently transcribed toward rcsB, which follows rcsD in what appears to be a two-gene operon. Here, it is reported that the overproduction of the rcsB gene represses rcsD transcription, but has a weak effect on its ...
Source: FEMS Microbiology Letters - September 22, 2009 Category: Microbiology Authors: María de las Mercedes Pescaretti, Roberto Morero, Mónica A. Delgado Source Type: journals

Functional analysis of γ-carotene ketolase involved in the carotenoid biosynthesis of Deinococcus radioduransEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Deinococcus radiodurans strain R1 synthesizes a unique ketocarotenoid product named deinoxanthin. The detailed steps involved in the biosynthesis of deinoxanthin remain unresolved. A carotene ketolase homologue encoded by dr0093 was inactivated by gene mutation to verify its function in the native host D. radiodurans. Analysis of the carotenoids in the resultant mutant R1[Delta]crtO demonstrated that dr0093 encodes [gamma]-carotene ketolase (CrtO) catalysing the introduction of one keto group into the C-4 position of [gamma]-carotene derivatives to form ketolated carotenoids. The mutant R1[Delta]crtO became more sensitive ...
Source: FEMS Microbiology Letters - September 20, 2009 Category: Microbiology Authors: Zongtao Sun, Shaochuan Shen, Bing Tian, Hu Wang, Zhenjian Xu, Liangyan Wang, Yuejin Hua Source Type: journals

Dynamin inhibitor impairs Toxoplasma gondii invasionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The protozoan parasite Toxoplasma gondii infects its host cells through an active mechanism. In this work, we obtained evidence that host cells also play a fundamental role during the infection process. We found that previous incubation of the host cells, but not the parasites, with Dynasore, a small molecule that inhibits dynamin GTPase activity, markedly reduced the penetration of T. gondii tachyzoites into LLC-MK2 cells. In contrast, parasite adhesion to the host cell surface increased, as observed both by light and electron microscopy. Intriguingly, the few parasites internalized by Dynasore-treated cells remained in v...
Source: FEMS Microbiology Letters - September 20, 2009 Category: Microbiology Authors: Lucio Ayres Caldas, Márcia Attias, Wanderley de Souza Source Type: journals

Legionella pneumophila secretes an endoglucanase that belongs to the family-5 of glycosyl hydrolases and is dependent upon type II secretionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Examination of cell-free culture supernatants revealed that Legionella pneumophila strains secrete an endoglucanase activity. Legionella pneumophila lspF mutants were deficient for this activity, indicating that the endoglucanase is secreted by the bacterium's type II protein secretion (T2S) system. Inactivation of celA, encoding a member of the family-5 of glycosyl hydrolases, abolished the endoglucanase activity in L. pneumophila culture supernatants. The cloned celA gene conferred activity upon recombinant Escherichia coli. Thus, CelA is the major secreted endoglucanase of L. pneumophila. Mutants inactivated for celA gr...
Source: FEMS Microbiology Letters - September 20, 2009 Category: Microbiology Authors: Meghan M. Pearce, Nicholas P. Cianciotto Source Type: journals