[Show abstract][Hide abstract] ABSTRACT: Trichophyton rubrum, an anthropophilic and cosmopolitan fungus, is the most common agent of superficial mycoses. In this study, T. rubrum infection was modeled by adding human skin sections to a limited medium containing glucose, and cDNA microarrays were used to monitor T. rubrum gene expression patterns on a global level. We observed that exposure to human skin resulted in up-regulation of the expression levels of T. rubrum genes related to many cellular and biological processes, including transcription and translation; metabolism and secondary transport; stress response; and signaling pathways. These results provide a reference set of T. rubrum genes whose expression patterns change upon infection and reveal previously unknown genes that probably correspond to proteins that should be considered as virulence factor candidates and potential new drug targets for T. rubrum infection.
Journal of Medical Microbiology 02/2014; · 2.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Accumulating evidence demonstrates that non-coding RNAs (ncRNAs) are indispensable components of many organisms and play important roles in cellular events, regulation, and development.
Here, we analysed the small non-coding RNA (ncRNA) transcriptome of Trichophyton rubrum by constructing and sequencing a cDNA library from conidia and mycelia. We identified 352 ncRNAs and their corresponding genomic loci. These ncRNA candidates included 198 entirely novel ncRNAs and 154 known ncRNAs classified as snRNAs, snoRNAs and other known ncRNAs. Further bioinformatic analysis detected 96 snoRNAs, including 56 snoRNAs that had been annotated in other organisms and 40 novel snoRNAs. All snoRNAs belonged to two major classes--C/D box snoRNAs and H/ACA snoRNAs--and their potential target sites in rRNAs and snRNAs were predicted. To analyse the evolutionary conservation of the ncRNAs in T. rubrum, we aligned all 352 ncRNAs to the genomes of six dermatophytes and to the NCBI non-redundant nucleotide database (NT). The results showed that most of the identified snRNAs were conserved in dermatophytes. Of the 352 ncRNAs, 102 also had genomic loci in other dermatophytes, and 27 were dermatophyte-specific.
Our systematic analysis may provide important clues to the function and evolution of ncRNAs in T. rubrum. These results also provide important information to complement the current annotation of the T. rubrum genome, which primarily comprises protein-coding genes.
[Show abstract][Hide abstract] ABSTRACT: Tuberculosis (TB) is an infectious bacterial disease that causes morbidity and mortality, especially in developing countries. Although the efficacy against TB has displayed a high degree of variability (0-80%) in different trials, Mycobacterium bovis bacillus Calmette-Guerin (BCG) has been recognized as an important weapon for preventing TB worldwide for over 80 years. Because secreted proteins often play vital roles in the interaction between bacteria and host cells, the secretome of mycobacteria is considered to be an attractive reservoir of potential candidate antigens for the development of novel vaccines and diagnostic reagents. In this study, we performed a proteomic analysis of BCG culture filtrate proteins using SDS-PAGE and high-resolution Fourier transform mass spectrometry. In total, 239 proteins (1555 unique peptides) were identified, including 185 secreted proteins or lipoproteins. Furthermore, 17 novel protein products not annotated in the BCG database were detected and validated by RT-PCR at the transcriptional level. Additionally, the translational start sites of 52 proteins were confirmed, and 22 proteins were validated by extension of the translational start sites based on N-terminus-derived peptides. Compared with previous studies on the mycobacterial secretome, there are 103 secreted proteins that have not been reported that are unique to our study. The physicochemical characteristics of the secreted proteins were determined. Major components from the culture supernatant, including low-molecular-weight antigens, lipoproteins, PE and PPE family proteins and Mce family proteins, were discussed; some components represent potential predominant antigens in the humoral and cellular immune responses.
[Show abstract][Hide abstract] ABSTRACT: Trichophyton rubrum (T. rubrum) is a common superficial fungus. Molecular and genetic studies of T. rubrum are still limited. In this paper, we report the global analysis of gene expression profiles at different growth phases using cDNA microarray technology. A total of 2044 differentially expressed genes were obtained and clustered into three expression patterns. Our data confirmed previous results that many mRNAs were pre-stored in the conidia of T. rubrum. Transcriptional profiling and function analysis showed that some glycolytic enzymes share similar expression patterns and may be coregulated during the transition of growth phases. Some genes involved in small GTPase signaling pathways, and in cAMP-dependent and MAPK regulation pathways were induced in response to the growth dynamics of T. rubrum. Although the detailed biological roles of these T. rubrum genes are still unknown, our results suggest that these genes may be involved in regulation mechanisms in the life cycle of the fungus.
Science China. Life sciences 06/2011; 54(7):675-82. · 2.02 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Bacillus cereus strain Q1 was isolated from a deep-subsurface oil reservoir in the Daqing oil field in northeastern China. This strain is able to produce biosurfactants and to survive in extreme environments. Here we report the finished and annotated genome sequence of this organism.
Journal of bacteriology 01/2009; 191(3):1120-1. · 3.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In China, comparatively little research has been directed at serogroup B meningococci, which are mainly isolated from healthy individuals. We attempted to study the genotypic characterization of Neisseria meningitidis serogroup B strains.
We analyzed 150 N. meningitidis strains isolated in China during 1975-2005 by multilocus sequence typing (MLST) and porA typing.
A total of 88 different sequence types (STs) were identified by MLST, 73 of which were newly identified. Seven complexes previously identified in other countries and three unique clonal lineages first identified in China were detected, seven of which had previously been described as 'hyperinvasive meningococcal lineages'. Several lineages were found in specified period. A total of 63 different porA types were found, 11 of which were novel. The most common porA types were P1.5-1,2-2 (17 isolates), P1.5-1,10-4 (12 isolates), P1.5-2,2-2 (eight isolates) and P1.7-2,4 (seven isolates).
In this context, serogroup B meningococci provide a diverse, continually reassorted gene pool from which new genotypes arise. The most important mechanism is probably horizontal genetic exchange among N. meningitidis serogroup B strains, possibly resulting in the emergence of new meningococcal clones. These results may help our understanding of the genotypic distribution of serogroup B meningococci and provide clues for further study of this organism.
The Journal of infection 04/2008; 56(3):211-8. · 4.13 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: An outbreak associated with Streptococcus suis infection in humans emerged in Sichuan province, China in 2005. The outbreak is atypical for the apparent large number of human cases, high fatality rate and geographical spread. To determine whether the bacterium has changed, we compared both human and animal isolates from the Sichuan outbreak with those collected previously within China and in other countries using whole genome PCR scanning (WGPScaning) comparative sequencing of several known virulence factor genes and multilocus sequence typing (MLST) analysis. WGPScanning analysis showed that all primer pairs yielded PCR products of the expected sizes in all four strains tested. The nucleotide sequences of all the detected virulence factor genes are identical in the four strains and MLST results showed that the four isolates studied and reference strain all belonged to the ST1 complex. No new genetic changes were found in the genome structure of the isolates from this Sichuan outbreak.
Science in China Series C Life Sciences 02/2008; 51(1):21-6. · 1.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ten outbreaks of a new serogroup C meningococcal disease emerged during 2003-2005 in China. The multilocus sequence typing results indicated that unique sequence type 4821 clone meningococci were responsible for these outbreaks. Herein, we determined the entire genomic DNA sequence of serogroup C isolate 053442, which belongs to ST-4821. Comparison of 053442 gene contents with other meningococcal genomes shows that they have similar characteristics, including thousands of repetitive elements and simple sequence repeats, numerous phase-variable genes, and similar virulence-related factors. However, many strain-specific regions were found in each genome. We also present the results of a genomic comparison of 28 ST-4821 complex isolates that were isolated from different serogroups using comparative genomic hybridization analysis. Genome comparison between the newly emerged hyperinvasive isolates belonging to different serogroups will further our understanding of their respective pathogenetic mechanisms.
[Show abstract][Hide abstract] ABSTRACT: An increase in the number of serogroup C meningococcal disease cases occurred in China from September 2003 to January 2006 as a result of several successive outbreaks. In addition, the proportion of serogroup C Neisseria meningitidis isolates from sporadic cases and carriers has also increased. In this study, 113 serogroup C meningococcal isolates were characterized by multilocus sequence typing (MLST) and PorA typing. These isolates comprised those from outbreak cases and their close contacts, the national carriage survey conducted during the same period and some historical isolates from 1966-2002. Twenty MLST sequence types (STs) and 21 PorA variable region (VR) types were identified in the collection. The ST-4821 complex, a newly identified lineage, was the most prevalent lineage (95/113). These data also showed a high level of diversification of serogroup C isolates, as indicated by the number of variants of the ST-4821 clone and the VR types present. There were ten PorA VR types among the ST-4821 isolates, and certain VR types (P1.7-2,14, P1.12-1,16-8) were associated with isolates from outbreak cases. The results of this study allow us to draw a profile of the molecular characteristics of serogroup C strains in China. These data are helpful for monitoring the spread of virulent strains and will provide valuable information for the prevention of bacterial meningitis in China.
Journal of Medical Microbiology 10/2007; 56(Pt 9):1224-9. · 2.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To serologically and genetically characterize other serogroups (except A, B, and C) of Neisseria meningitidis isolates in China, we collected 56 strains of other serogroups, identified by serogroup typing and multilocus sequence typing (MLST). All of them are non-invasive isolates. The serogroups of the 56 Chinese isolates were W135 (11 isolates), Y (4), X (15), 29E (15), D (1), H (4), I (3), K (2), and non-groupable (1). By MLST, 34 different sequence types (STs) were identified, 28 of which were not found in the MLST database as of July 2006 and seemed to be unique to China. Statistical analysis of the MLST results revealed that, although the Chinese isolates seemed to be genetically divergent, they could be classified into 5 major clonal groups and other minor groups. Among these isolates, none of the well-documented ST complexes found worldwide was present.
[Show abstract][Hide abstract] ABSTRACT: The theory that Shigella is derived from multiple independent origins of Escherichia coli (Pupo et al. 2000) has been challenged by recent findings that the virulence plasmids (VPs) and the chromosomes share a similar evolutionary history (Escobar-Paramo et al. 2003), which suggests that an ancestral VP entered an E. coli strain only once, which gave rise to Shigella spp. In an attempt to resolve these conflicting theories, we constructed three phylogenetic trees in this study: a robust chromosomal tree using 23 housekeeping genes from 46 strains of Shigella and enteroinvasive E. coli (EIEC), a chromosomal tree using 4 housekeeping genes from 19 EcoR strains and 46 Shigella/EIEC strains, and a VP tree using 5 genes outside of the VP cell-entry region from 38 Shigella/EIEC strains. Both chromosomal trees group Shigella into three main clusters and five outliers, and strongly suggest that Shigella has multiple origins within E. coli. Most strikingly, the VP tree shows that the VPs from two main Shigella clusters, C1 and C2, are more closely related, which contradicts the chromosomal trees that place C2 and C3 next to each other but C1 at a distance. Additionally, we have identified a complete tra operon of the F-plasmid in the genome sequence of an EIEC strain and found that two other EIEC strains are also likely to possess a complete tra operon. All lines of evidence support an alternative multiorigin theory that transferable diverse ancestral VPs entered diverse origins of E. coli multiple times during a prolonged period of time, resulting in Shigella species with diverse genomes but similar pathogenic properties.
Journal of Molecular Evolution 02/2007; 64(1):71-9. · 2.15 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Conidia are considered to be the primary cause of infections by Trichophyton rubrum.
We have developed a cDNA microarray containing 10250 ESTs to monitor the transcriptional strategy of conidial germination. A total of 1561 genes that had their expression levels specially altered in the process were obtained and hierarchically clustered with respect to their expression profiles. By functional analysis, we provided a global view of an important biological system related to conidial germination, including characterization of the pattern of gene expression at sequential developmental phases, and changes of gene expression profiles corresponding to morphological transitions. We matched the EST sequences to GO terms in the Saccharomyces Genome Database (SGD). A number of homologues of Saccharomyces cerevisiae genes related to signalling pathways and some important cellular processes were found to be involved in T. rubrum germination. These genes and signalling pathways may play roles in distinct steps, such as activating conidial germination, maintenance of isotropic growth, establishment of cell polarity and morphological transitions.
Our results may provide insights into molecular mechanisms of conidial germination at the cell level, and may enhance our understanding of regulation of gene expression related to the morphological construction of T. rubrum.
[Show abstract][Hide abstract] ABSTRACT: In this study, we constructed single mutants MTS-1, MTS-2 of IroN and ShuA gene and double mutant MTS of them in Shigella dysenteriae A1 strain 51197 by insert and absence. The functional detection of every mutant was performed at the level of culture medium and cell experiment. The gene expression profiles of the mutants and the wild-type strains under iron-enriched and iron-limited conditions were analyzed by the SD51197 whole genomic microarray. The results showed that all the mutants grew obviously less well than the wild-type strains in L broth appending iron chelator DIP. The addition of iron to the cultures can stimulate the growth of mutants back to wild-type levels. In either the experiments on the ability of intracellular multiplication or the cell-to-cell spread in HeLa and U937 cell lines, mutants showed no obvious change in virulence compared with the parental strain SD51197. However when DIP was added to the cultured HeLa cells, the ability of intracellular multiplication of MTS-1, MTS-2, MTS has reduced about 23.4%, 25.2%, 43.6% respectively. The analysis of expression profiles under the iron-limited condition showed that the mutants were more sensitive for the changes of iron deficiency than the wild-type strains, many genes have been altered. Up-regulated genes mainly involved genes of transcription, coenzyme metabolism, amino acid transport and metabolism, and unknown functional genes, while down-regulated genes mainly involved genes of energy and carbohydrate metabolism and unknown function genes; the expression levels of known iron-transport associated genes generally showed up-regulated. The results demonstrated that iron-transport associated genes IroN, ShuA were likely to have some effects on the virulence and growth of S. dysenteriae.
Science in China Series C Life Sciences 07/2006; 49(3):251-8. · 1.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We determined and analyzed the Shigella flexneri serotype 5 (pSF5) and S. dysenteriae serotype 1 (pSD1) virulence plasmid genomes. The total length of pSF5 is 136513 bp, including 165 open reading frames (ORFs). Of these ORFs, 133 were identified and 32 of those had no significant homology to proteins with known functions. The length of pSD1 is 182545 bp, including 224 ORFs, of which we identified 181. The remaining 43 ORFs were not significantly homologous to proteins with known functions. The insertion sequence (IS) elements are 53787 bp in pSF5, and 49616 bp in pSD1, which represents 39.4% and 27.1% of the genome, respectively. There are 22 IS element types in pSF5 and pSD1, among which we report ISEc8 and ISSbo6 for the first time in the Shigella virulence plasmid. Compared to pCP301, there are a large number of deleted genes and gene inversions in both pSF5 and pSD1. The ipa-mxi-spa locus in pSF5 is completely absent, and the genes related to the O-antigen biosynthesis are partially missing. In contrast, the above genes in pSD1 are integral, with the exception of virF. The whole genome analysis of the two plasmids shows that the loss of genes related to gene invasion or regulation also obliterates the ability of pPF5 and pSD1 to bind Congo red (Crb). Whether these genes determine the Crb function requires continued investigation.
Science in China Series C Life Sciences 05/2006; 49(2):141-8. · 1.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Comparative Genomic Hybridization (CGH) microarray analysis was used to compare the genomic compositions of all eighteen Shigella boydii serotype representative strains. The results indicated the genomic "backbone" of this subgroup contained 2552 ORFs homologous to nonpathogenic E. coli K12. Compared with the genome of K12199 ORFs were found to be absent in all S. boydii serotype representatives, including mainly outer membrane protein genes and O-antigen biosynthesis genes. Yet the specific ORFs of S. boydii subgroup contained basically bacteriophage genes and the function unknown (FUN) genes. Some iron metabolism, transport and type II secretion system related genes were found in most representative strains. According to the CGH phylogenetic analysis, the eighteen S. boydii serotype representatives were divided into four groups, in which serotype C13 strain was remarkably distinguished from the other serotype strains. This grouping result corresponded to the distribution of some metabolism related genes. Furthermore, the analysis of genome backbone genes, specific genes, and the phylogenetic trees allowed us to discover the evolution laws of S. boydii and to find out important clues to pathogenesis research, vaccination and the therapeutic medicine development.
Science in China Series C Life Sciences 03/2006; 49(1):46-52. · 1.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Dermatophytes are the primary causative agent of dermatophytoses, a disease that affects billions of individuals worldwide. Trichophyton rubrum is the most common of the superficial fungi. Although T. rubrum is a recognized pathogen for humans, little is known about how its transcriptional pattern is related to development of the fungus and establishment of disease. It is therefore necessary to identify genes whose expression is relevant to growth, metabolism and virulence of T. rubrum.
We generated 10 cDNA libraries covering nearly the entire growth phase and used them to isolate 11,085 unique expressed sequence tags (ESTs), including 3,816 contigs and 7,269 singletons. Comparisons with the GenBank non-redundant (NR) protein database revealed putative functions or matched homologs from other organisms for 7,764 (70%) of the ESTs. The remaining 3,321 (30%) of ESTs were only weakly similar or not similar to known sequences, suggesting that these ESTs represent novel genes.
The present data provide a comprehensive view of fungal physiological processes including metabolism, sexual and asexual growth cycles, signal transduction and pathogenic mechanisms.
[Show abstract][Hide abstract] ABSTRACT: Influenza B virus is a cause of substantial morbidity and mortality in humans and current vaccination strategies and antiviral drugs only provide limited protection. Here, we report the evaluation of small interfering RNA (siRNA) for repression of viral replication in cultured cells as well as in chicken embryos. Several siRNAs targeting conserved regions of the virus (in chemically synthesized or plasmid-encoded forms) were found to effectively block the replication of the influenza B virus. The siRNAs were found to offer broad protection over several strains of influenza B virus (B/Beijing/76/98, B/Beijing/37/99 and B/Jiangsu/10/03) that differ substantially in their genetic content. The antiviral effects of 500 ng siRNA-encoding plasmids or 60 nmoles synthetic siRNA were found to be comparable to that of 3.6 microg ribavirin. These results indicated that RNA interference warrants further study for management of influenza B virus infections.
[Show abstract][Hide abstract] ABSTRACT: Shigella bacteria cause dysentery, which remains a significant threat to public health. Shigella flexneri is the most common species in both developing and developed countries. Five Shigella genomes have been sequenced, revealing dynamic and diverse features. To investigate the intra-species diversity of S. flexneri genomes further, we have sequenced the complete genome of S. flexneri 5b strain 8401 (abbreviated Sf8401) and compared it with S. flexneri 2a (Sf301).
The Sf8401 chromosome is 4.5-Mb in size, a little smaller than that of Sf301, mainly because the former lacks the SHI-1 pathogenicity island (PAI). Compared with Sf301, there are 6 inversions and one translocation in Sf8401, which are probably mediated by insertion sequences (IS). There are clear differences in the known PAIs between these two genomes. The bacteriophage SfV segment remaining in SHI-O of Sf8401 is clearly larger than the remnants of bacteriophage SfII in Sf301. SHI-1 is absent from Sf8401 but a specific related protein is found next to the pheV locus. SHI-2 is involved in one intra-replichore inversion near the origin of replication, which may change the expression of iut/iuc genes. Moreover, genes related to the glycine-betaine biosynthesis pathway are present only in Sf8401 among the known Shigella genomes.
Our data show that the two S. flexneri genomes are very similar, which suggests a high level of structural and functional conservation between the two serotypes. The differences reflect different selection pressures during evolution. The ancestor of S. flexneri probably acquired SHI-1 and SHI-2 before SHI-O was integrated and the serotypes diverged. SHI-1 was subsequently deleted from the S. flexneri 5b genome by recombination, but stabilized in the S. flexneri 2a genome. These events may have contributed to the differences in pathogenicity and epidemicity between the two serotypes of S. flexneri.
[Show abstract][Hide abstract] ABSTRACT: Four gene clusters associated with denitrification were identified in the genome of A1501 strain, nar, nir, nor and nos, including 40 genes totally, which encode proteins for substance transportation, gene regulation and reductases. The three gene clusters, nir, nor and nos are adjacent on chromosome and are far from nar gene cluster. Compared with other denitrifying bacteria, the 40 denitrification genes in A1501 strain compose a complete denitrification catalysis system. In A1501 strain, this system has the following characteristics: (i) only one copy of narK gene is found in nar gene cluster; (ii) a narM gene is present between narK and narG; (iii) two genes, dnarE and orfl are identified at downstream of narX and narL genes, of which dnrE perhaps is a transcriptional factor belonging to FNR family; (iv) there are 16 nir genes in A1501, the most in the known denitrifying bacteria; (v) it is for the first time that norR gene has been found in A1501 and also in Pseudomonas; (vi) nos gene cluster is relatively conservative, with a completely identical composition and arrangement of genome to the reference bacteria strain.
Science in China Series C Life Sciences 01/2006; 48(6):585-92. · 1.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The complete sequence of pSS, which is the large virulence plasmid of Shigella sonnei, was determined. The 214-kb plasmid is composed of segments of virulence-associated genes, the O-antigen gene clusters, a range of replication and maintenance genes, and large numbers of insertion sequence (IS) elements. Two hundred and forty-one open reading frames (ORFs) were identified, of which 117 are highly homologous to IS elements or transposases, 57 are homologous to known pathogenesis-associated proteins, and 30 are related to replication, plasmid maintenance, or other metabolic functions. Thirty-seven ORFs have no similarity to proteins with a known function, including two with no significant similarity to any hypothetical proteins. Interestingly, 10 ORFs encoding O-antigen gene clusters were identified on the plasmid and this is markedly different from most other Shigella spp. virulent plasmids. A novel toxin-antitoxin system, a series of stbDE homologs, was found on the plasmid immediately downstream of the replication region; the sole segregation stability system may be responsible for the instability of pSS. The pSS plasmid is a mixture of genes with different origins and functions. The sequence suggests a remarkable history of IS-mediated recombination and acquisition of DNA across a range of bacterial species.