共查询到20条相似文献,搜索用时 31 毫秒
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Ramona Barbieri Marianna Pesce Simonetta Franchelli Ilaria Baldelli Andrea De Maria Anna Marchese 《BMC microbiology》2015,15(1)
Background
Staphylococcus epidermidis and S. aureus have been identified as the most common bacteria responsible for sub-clinical and overt breast implant infections and their ability to form biofilm on the implant as been reported as the essential factor in the development of this type of infections. Biofilm formation is a complex process with the participation of several distinct molecules, whose relative importance in different clinical settings has not yet been fully elucidated. To our knowledge this is the first study aimed at characterizing isolates causing breast peri-implant infections.Results
Thirteen S. aureus and seven S. epidermidis causing breast peri-implant infections were studied.Using the broth microdilution method and the E-test, the majority of the strains were susceptible to all antibiotics tested. Methicillin resistance was detected in two S. epidermidis. All strains had different RAPD profiles and were able to produce biofilms in microtitre plate assays but, while all S. aureus carried and were able to express icaA and icaD genes, this was only true for one S. epidermidis. Biofilm development was glucose- and NaCl-induced (5 S. aureus and 1 S. epidermidis) or glucose-induced (the remaining strains). Proteinase K and sodium metaperiodate treatment had different effects on biofilms dispersion revealing that the strains studied were able to produce chemically different types of extracellular matrix mediating biofilm formation.All S. aureus strains harboured and expressed the atlA, clfA, FnA, eno and cna genes and the majority also carried and expressed the sasG (10/13), ebpS (10/13) genes.All S. epidermidis strains harboured and expressed the atlE, aae, embp genes, and the majority (six strains) also carried and expressed the fbe, aap genes.Genes for S. aureus capsular types 5 and 8 were almost equally distributed. The only leukotoxin genes detected were lukE/lukD (6/13).Conclusions
S. aureus and S. epidermidis breast peri-implant infections are caused by heterogeneous strains with different biofilm development mechanisms.Since the collagen adhesin (cna) gene is not ubiquitously distributed among S. aureus, this protein could have an important role in the cause of breast peri-implant infections.Electronic supplementary material
The online version of this article (doi:10.1186/s12866-015-0368-x) contains supplementary material, which is available to authorized users. 相似文献5.
Background
Transposable elements constitute an important part of the genome and are essential in adaptive mechanisms. Transposition events associated with phenotypic changes occur naturally or are induced in insertional mutant populations. Transposon mutagenesis results in multiple random insertions and recovery of most/all the insertions is critical for forward genetics study. Using genome next-generation sequencing data and appropriate bioinformatics tool, it is plausible to accurately identify transposon insertion sites, which could provide candidate causal mutations for desired phenotypes for further functional validation.Results
We developed a novel bioinformatics tool, ITIS (Identification of Transposon Insertion Sites), for localizing transposon insertion sites within a genome. It takes next-generation genome re-sequencing data (NGS data), transposon sequence, and reference genome sequence as input, and generates a list of highly reliable candidate insertion sites as well as zygosity information of each insertion. Using a simulated dataset and a case study based on an insertional mutant line from Medicago truncatula, we showed that ITIS performed better in terms of sensitivity and specificity than other similar algorithms such as RelocaTE, RetroSeq, TEMP and TIF. With the case study data, we demonstrated the efficiency of ITIS by validating the presence and zygosity of predicted insertion sites of the Tnt1 transposon within a complex plant system, M. truncatula.Conclusion
This study showed that ITIS is a robust and powerful tool for forward genetic studies in identifying transposable element insertions causing phenotypes. ITIS is suitable in various systems such as cell culture, bacteria, yeast, insect, mammal and plant.Electronic supplementary material
The online version of this article (doi:10.1186/s12859-015-0507-2) contains supplementary material, which is available to authorized users. 相似文献6.
Joyce Wang Justin R Pritchard Louis Kreitmann Alexandre Montpetit Marcel A Behr 《BMC genomics》2014,15(1)
Background
Mycobacterium avium subsp. paratuberculosis (MAP) is an obligate intracellular pathogen that infects many ruminant species. The acquisition of foreign genes via horizontal gene transfer has been postulated to contribute to its pathogenesis, as these genetic elements are absent from its putative ancestor, M. avium subsp. hominissuis (MAH), an environmental organism with lesser pathogenicity. In this study, high-throughput sequencing of MAP transposon libraries were analyzed to qualitatively and quantitatively determine the contribution of individual genes to bacterial survival during infection.Results
Out of 52384 TA dinucleotides present in the MAP K-10 genome, 12607 had a MycoMarT7 transposon in the input pool, interrupting 2443 of the 4350 genes in the MAP genome (56%). Of 96 genes situated in MAP-specific genomic islands, 82 were disrupted in the input pool, indicating that MAP-specific genomic regions are dispensable for in vitro growth (odds ratio = 0.21). Following 5 independent in vivo infections with this pool of mutants, the correlation between output pools was high for 4 of 5 (R = 0.49 to 0.61) enabling us to define genes whose disruption reproducibly reduced bacterial fitness in vivo. At three different thresholds for reduced fitness in vivo, MAP-specific genes were over-represented in the list of predicted essential genes. We also identified additional genes that were severely depleted after infection, and several of them have orthologues that are essential genes in M. tuberculosis.Conclusions
This work indicates that the genetic elements required for the in vivo survival of MAP represent a combination of conserved mycobacterial virulence genes and MAP-specific genes acquired via horizontal gene transfer. In addition, the in vitro and in vivo essential genes identified in this study may be further characterized to offer a better understanding of MAP pathogenesis, and potentially contribute to the discovery of novel therapeutic and vaccine targets.Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-415) contains supplementary material, which is available to authorized users. 相似文献7.
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Background
The two-spotted spider mite, Tetranychus urticae, is infected with Wolbachia, which have the ability to manipulate host reproduction and fitness. MicroRNAs (miRNAs) are small non-coding RNAs that are involved in many biological processes such as development, reproduction and host-pathogen interactions. Although miRNA was observed to involve in Wolbachia-host interactions in the other insect systems, its roles have not been fully deciphered in the two-spotted spider mite.Results
Small RNA libraries of infected and uninfected T. urticae for both sexes (in total four libraries) were constructed. By integrating the mRNA data originated from the same samples, the target genes of the differentially expressed miRNAs were predicted. Then, GO and pathway analyses were performed for the target genes. Comparison of libraries showed that Wolbachia infection significantly regulated 91 miRNAs in females and 20 miRNAs in males, with an overall suppression of miRNAs in Wolbachia-infected libraries. A comparison of the miRNA and mRNA data predicted that the differentially expressed miRNAs negatively regulated 90 mRNAs in females and 9 mRNAs in males. An analysis of target genes showed that Wolbachia-responsive miRNAs regulated genes with function in sphingolipid metabolism, lysosome function, apoptosis and lipid transporting in both sexes, as well as reproduction in females.Conclusion
Comparisons of the miRNA and mRNA data can help to identify miRNAs and miRNA target genes involving in Wolbachia-host interactions. The molecular targets identified in this study should be useful in further functional studies.Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-1122) contains supplementary material, which is available to authorized users. 相似文献9.
Stefano Pessina Stefano Pavan Domenico Catalano Alessandra Gallotta Richard GF Visser Yuling Bai Mickael Malnoy Henk J Schouten 《BMC genomics》2014,15(1)
Background
Powdery mildew (PM) is a major fungal disease of thousands of plant species, including many cultivated Rosaceae. PM pathogenesis is associated with up-regulation of MLO genes during early stages of infection, causing down-regulation of plant defense pathways. Specific members of the MLO gene family act as PM-susceptibility genes, as their loss-of-function mutations grant durable and broad-spectrum resistance.Results
We carried out a genome-wide characterization of the MLO gene family in apple, peach and strawberry, and we isolated apricot MLO homologs through a PCR-approach. Evolutionary relationships between MLO homologs were studied and syntenic blocks constructed. Homologs that are candidates for being PM susceptibility genes were inferred by phylogenetic relationships with functionally characterized MLO genes and, in apple, by monitoring their expression following inoculation with the PM causal pathogen Podosphaera leucotricha.Conclusions
Genomic tools available for Rosaceae were exploited in order to characterize the MLO gene family. Candidate MLO susceptibility genes were identified. In follow-up studies it can be investigated whether silencing or a loss-of-function mutations in one or more of these candidate genes leads to PM resistance.Electronic supplementary material
The online version of this article (doi:10.1186/1471-2164-15-618) contains supplementary material, which is available to authorized users. 相似文献10.
Background
Anthocyanins are a group of flavonoid compounds. As a group of important secondary metabolites, they perform several key biological functions in plants. Anthocyanins also play beneficial health roles as potentially protective factors against cancer and heart disease. To elucidate the anthocyanin biosynthetic pathway in Brassica rapa, we conducted comparative genomic analyses between Arabidopsis thaliana and B. rapa on a genome-wide level.Results
In total, we identified 73 genes in B. rapa as orthologs of 41 anthocyanin biosynthetic genes in A. thaliana. In B. rapa, the anthocyanin biosynthetic genes (ABGs) have expanded and most genes exist in more than one copy. The anthocyanin biosynthetic structural genes have expanded through whole genome and tandem duplication in B. rapa. More structural genes located upstream of the anthocyanin biosynthetic pathway have been retained than downstream. More negative regulatory genes are retained in the anthocyanin biosynthesis regulatory system of B. rapa.Conclusions
These results will promote an understanding of the genetic mechanism of anthocyanin biosynthesis, as well as help the improvement of the nutritional quality of B. rapa through the breeding of high anthocyanin content varieties.Electronic supplementary material
The online version of this article (doi: 10.1186/1471-2164-15-426) contains supplementary material, which is available to authorized users. 相似文献11.
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Keven M Robinson Benjamin Lee Erich V Scheller Sivanarayana Mandalapu Richard I Enelow Jay K Kolls John F Alcorn 《Respiratory research》2015,16(1)
Background
Influenza is a common respiratory virus and Staphylococcus aureus frequently causes secondary pneumonia during influenza infection, leading to increased morbidity and mortality. Influenza has been found to attenuate subsequent Type 17 immunity, enhancing susceptibility to secondary bacterial infections. IL-27 is known to inhibit Type 17 immunity, suggesting a potential critical role for IL-27 in viral and bacterial co-infection.Methods
A murine model of influenza and Staphylococcus aureus infection was used to mimic human viral, bacterial co-infection. C57BL/6 wild-type, IL-27 receptor α knock-out, and IL-10 knock-out mice were infected with Influenza H1N1 (A/PR/8/34) or vehicle for 6 days followed by challenge with Staphylococcus aureus or vehicle for 24 hours. Lung inflammation, bacterial burden, gene expression, and cytokine production were determined.Results
IL-27 receptor α knock-out mice challenged with influenza A had increased morbidity compared to controls, but no change in viral burden. IL-27 receptor α knock-out mice infected with influenza displayed significantly decreased IL-10 production compared to wild-type. IL-27 receptor α knock-out mice co-infected with influenza and S. aureus had improved bacterial clearance compared to wild-type controls. Importantly, there were significantly increased Type 17 responses and decreased IL-10 production in IL-27 receptor α knock-out mice. Dual infected IL-10−/− mice had significantly less bacterial burden compared to dual infected WT mice.Conclusions
These data reveal that IL-27 regulates enhanced susceptibility to S. aureus pneumonia following influenza infection, potentially through the induction of IL-10 and suppression of IL-17. 相似文献17.
Beatriz Vásquez-Soto Nicolás Manríquez Mirna Cruz-Amaya Jan Zouhar Natasha V Raikhel Lorena Norambuena 《Biological research》2015,48(1)
Background
A highly regulated trafficking of cargo vesicles in eukaryotes performs protein delivery to a variety of cellular compartments of endomembrane system. The two main routes, the secretory and the endocytic pathways have pivotal functions in uni- and multi-cellular organisms. Protein delivery and targeting includes cargo recognition, vesicle formation and fusion. Developing new tools to modulate protein trafficking allows better understanding the endomembrane system mechanisms and their regulation. The compound Sortin2 has been described as a protein trafficking modulator affecting targeting of the vacuolar protein carboxypeptidase Y (CPY), triggering its secretion in Saccharomyces cerevisiae.Results
A reverse chemical-genetics approach was used to identify key proteins for Sortin2 bioactivity. A genome-wide Sortin2 resistance screen revealed six yeast deletion mutants that do not secrete CPY when grown at Sortin2 condition where the parental strain does: met18, sla1, clc1, dfg10, dpl1 and yjl175w. Integrating mutant phenotype and gene ontology annotation of the corresponding genes and their interactome pointed towards a high representation of genes involved in the endocytic process. In wild type yeast endocytosis towards the vacuole was faster in presence of Sortin2, which further validates the data of the genome-wide screen. This effect of Sortin2 depends on structural features of the molecule, suggesting compound specificity. Sortin2 did not affect endocytic trafficking in Sortin2-resistant mutants, strongly suggesting that the Sortin2 effects on the secretory and endocytic pathways are linked.Conclusions
Overall, the results reveal that Sortin2 enhances the endocytic transport pathway in Saccharomyces cerevisiae. This cellular effect is most likely at the level where secretory and endocytic pathways are merged. Them Sortin2 specificity over the endomembrane system places it as a powerful biological modulator for cell biology.Electronic supplementary material
The online version of this article (doi:10.1186/s40659-015-0032-9) contains supplementary material, which is available to authorized users. 相似文献18.
Albert B Raquin C Prigent M Nadot S Brisset F Yang M Ressayre A 《Annals of botany》2011,107(8):1421-1426
Background and Aims
The tam (tardy asynchronous meiosis) mutant of Arabidopsis thaliana, which exhibits a modified cytokinesis with a switch from simultaneous to successive cytokinesis, was used to perform a direct test of the implication of cytokinesis in aperture-pattern ontogeny of angiosperm pollen grains. The aperture pattern corresponds to the number and arrangement of apertures (areas of the pollen wall permitting pollen tube germination) on the surface of the pollen grain.Methods
A comparative analysis of meiosis and aperture distribution was performed in two mutant strains of arabidopsis: quartet and quartet-tam.Key Results
While the number of apertures is not affected in the quartet-tam mutant, the arrangement of the three apertures is modified compared with the quartet, resulting in a different aperture pattern.Conclusions
These results directly demonstrate the relationship between the type of sporocytic cytokinesis and pollen aperture-pattern ontogeny. 相似文献19.