Genomic island excisions in Bordetella petrii

Background  

Among the members of the genus Bordetella B. petrii is unique, since it is the only species isolated from the environment, while the pathogenic Bordetellae are obligately associated with host organisms. Another feature distinguishing B. petrii from the other sequenced Bordetellae is the presence of a large number of mobile genetic elements including several large genomic regions with typical characteristics of genomic islands collectively known as integrative and conjugative elements (ICEs). These elements mainly encode accessory metabolic factors enabling this bacterium to grow on a large repertoire of aromatic compounds.     

A family history of DUX4: phylogenetic analysis of DUXA, B, C and Duxbl reveals the ancestral DUX gene

Background  

DUX4 is causally involved in the molecular pathogenesis of the neuromuscular disorder facioscapulohumeral muscular dystrophy (FSHD). It has previously been proposed to have arisen by retrotransposition of DUXC, one of four known intron-containing DUX genes. Here, we investigate the evolutionary history of this multi-member double-homeobox gene family in eutherian mammals.     

Effect of iron on the expression of sirR and sitABC in biofilm-associated Staphylococcus epidermidis

Background  

Different gene expression patterns correlate with the altered phenotype in biofilm-associated bacteria. Iron and iron-linked genes are thought to play a key-role in biofilm formation. The expression of Fe-linked genes (sirR, sitABC operon) in Staphylococcus epidermidis, was compared in planktonic versus sessile bacteria in vitro and in vivo in a subcutaneous foreign body rat model.     

Multiple invasions of Gypsy and Micropia retroelements in genus Zaprionus and melanogaster subgroup of the genus Drosophila

Background  

The Zaprionus genus shares evolutionary features with the melanogaster subgroup, such as space and time of origin. Although little information about the transposable element content in the Zaprionus genus had been accumulated, some of their elements appear to be more closely related with those of the melanogaster subgroup, indicating that these two groups of species were involved in horizontal transfer events during their evolution. Among these elements, the Gypsy and the Micropia retroelements were chosen for screening in seven species of the two Zaprionus subgenera, Anaprionus and Zaprionus.     

Prezygotic reproductive isolation between Saccharomyces cerevisiae and Saccharomyces paradoxus

Background  

Matings between different Saccharomyces sensu stricto yeast species produce sexually sterile hybrids, so individuals should avoid mating with other species. Any mechanism that reduces the frequency of interspecific matings will confer a selective advantage. Here we test the ability of two closely-related Saccharomyces sensu stricto species to select their own species as mates and avoid hybridisation.     

Identification and characterization of the heme-binding proteins SeShp and SeHtsA of Streptococcus equi subspecies equi

Background  

Heme is a preferred iron source of bacterial pathogens. Streptococcus equi subspecies equi is a bacterial pathogen that causes strangles in horses. Whether S. equi has a heme acquisition transporter is unknown.     

Resistance to organic hydroperoxides requires ohr and ohrR genes in Sinorhizobium meliloti

Background  

Sinorhizobium meliloti is a symbiotic nitrogen-fixing bacterium that elicits nodules on roots of host plants Medicago sativa. During nodule formation bacteria have to withstand oxygen radicals produced by the plant. Resistance to H₂O₂ and superoxides has been extensively studied in S. meliloti. In contrast resistance to organic peroxides has not been investigated while S. meliloti genome encodes putative organic peroxidases. Organic peroxides are produced by plants and are highly toxic. The resistance to these oxygen radicals has been studied in various bacteria but never in plant nodulating bacteria.     

Paracoccidioides brasiliensis pancreatic destruction in Calomys callosus experimentally infected

Background  

The wild rodent Calomys callosus is notably resistant to Trypanosoma cruzi infection. In order to better characterize this animal model for experimental infections, we inoculated C. callosus intraperitoneally with Paracoccidioides brasiliensis, a thermally dimorphic fungus that causes a chronic disease with severe granuloma formation in the mouse and humans. The dissemination of P. brasiliensis cells through the lungs, liver, pancreas, and spleen was assessed by histological analysis.     

Binding of protegrin-1 to Pseudomonas aeruginosa and Burkholderia cepacia

Background  

Pseudomonas aeruginosa and Burkholderia cepacia infections of cystic fibrosis patients' lungs are often resistant to conventional antibiotic therapy. Protegrins are antimicrobial peptides with potent activity against many bacteria, including P. aeruginosa. The present study evaluates the correlation between protegrin-1 (PG-1) sensitivity/resistance and protegrin binding in P. aeruginosa and B. cepacia.     

Processing of predicted substrates of fungal Kex2 proteinases from Candida albicans, C. glabrata, Saccharomyces cerevisiae and Pichia pastoris

Background  

Kexin-like proteinases are a subfamily of the subtilisin-like serine proteinases with multiple regulatory functions in eukaryotes. In the yeast Saccharomyces cerevisiae the Kex2 protein is biochemically well investigated, however, with the exception of a few well known proteins such as the α-pheromone precursors, killer toxin precursors and aspartic proteinase propeptides, very few substrates are known. Fungal kex2 deletion mutants display pleiotropic phenotypes that are thought to result from the failure to proteolytically activate such substrates.     

Allelic diversity and phylogeny of homB, a novel co-virulence marker of Helicobacter pylori

Background  

The homB gene is a Helicobacter pylori disease-marker candidate, strongly associated with peptic ulcer disease, while homA, its paralogue gene with 90% sequence identity, is correlated with non-ulcer dyspepsia. The HomB encoded outer membrane protein was shown to contribute to the proinflammatory properties of H. pylori and also to be involved in bacterial adherence.     

Copia and Gypsy retrotransposons activity in sunflower (Helianthus annuus L.)

Background  

Retrotransposons are heterogeneous sequences, widespread in eukaryotic genomes, which refer to the so-called mobile DNA. They resemble retroviruses, both in their structure and for their ability to transpose within the host genome, of which they make up a considerable portion. Copia- and Gypsy-like retrotransposons are the two main classes of retroelements shown to be ubiquitous in plant genomes. Ideally, the retrotransposons life cycle results in the synthesis of a messenger RNA and then self-encoded proteins to process retrotransposon mRNA in double stranded extra-chromosomal cDNA copies which may integrate in new chromosomal locations.     

Polyploid evolution in Oryza officinalis complex of the genus Oryza

Background  

Polyploidization is a prominent process in plant evolution, whereas the mechanism and tempo-spatial process remained poorly understood. Oryza officinalis complex, a polyploid complex in the genus Oryza, could exemplify the issues not only for it covering a variety of ploidy levels, but also for the pantropical geographic pattern of its polyploids in Asia, Africa, Australia and Americas, in which a pivotal genome, the C-genome, witnessed all the polyploidization process.     

Ds tagging of BRANCHED FLORETLESS 1 (BFL1) that mediates the transition from spikelet to floret meristem in rice (Oryza sativa L)

Background  

The genetics of spikelet formation, a feature unique to grasses such as rice and maize, is yet to be fully understood, although a number of meristem and organ identity mutants have been isolated and investigated in Arabidopsis and maize. Using a two-element Ac/Ds transposon tagging system we have isolated a rice mutant, designated branched floretless 1 (bfl1) which is defective in the transition from spikelet meristem to floret meristem.     

Synergistic effect of imp/ostA and msbA in hydrophobic drug resistance of Helicobacter pylori

Background  

Contamination of endoscopy equipment by Helicobacter pylori (H. pylori) frequently occurs after endoscopic examination of H. pylori-infected patients. In the hospital, manual pre-cleaning and soaking in glutaraldehyde is an important process to disinfect endoscopes. However, this might not be sufficient to remove H. pylori completely, and some glutaraldehyde-resistant bacteria might survive and be passed to the next patient undergoing endoscopic examination through unidentified mechanisms. We identified an Imp/OstA protein associated with glutaraldehyde resistance in a clinical strain, NTUH-C1, from our previous study. To better understand and manage the problem of glutaraldehyde resistance, we further investigated its mechanism.     

Characterization of N -acylhomoserine lactone-degrading bacteria associated with the Zingiber officinale (ginger) rhizosphere: Co-existence of quorum quenching and quorum sensing in Acinetobacter and Burkholderia

Background  

Cell-to-cell communication (quorum sensing (QS)) co-ordinates bacterial behaviour at a population level. Consequently the behaviour of a natural multi-species community is likely to depend at least in part on co-existing QS and quorum quenching (QQ) activities. Here we sought to discover novel N -acylhomoserine lactone (AHL)-dependent QS and QQ strains by investigating a bacterial community associated with the rhizosphere of ginger (Zingiber officinale) growing in the Malaysian rainforest.     

Improving Salmonella vector with rec mutation to stabilize the DNA cargoes

Background  

Salmonella has been employed to deliver therapeutic molecules against cancer and infectious diseases. As the carrier for target gene(s), the cargo plasmid should be stable in the bacterial vector. Plasmid recombination has been reduced in E. coli by mutating several genes including the recA, recE, recF and recJ. However, to our knowledge, there have been no published studies of the effect of these or any other genes that play a role in plasmid recombination in Salmonella enterica.     

Coordinated spatial and temporal expression ofHox genes during embryogenesis in the acoelConvolutriloba longifissura

Background  

Hox genes are critical for patterning the bilaterian anterior-posterior axis. The evolution of their clustered genomic arrangement and ancestral function has been debated since their discovery. As acoels appear to represent the sister group to the remaining Bilateria (Nephrozoa), investigatingHox gene expression will provide an insight into the ancestral features of theHox genes in metazoan evolution.