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1.
Molecular chaperone proteins play a pivotal role in the protozoan parasite Leishmania donovani, controlling cell fate and ensuring intracellular survival. In higher eukaryotes, the so-called co-chaperone proteins are
required for client protein recognition and proper function of chaperones, among them the small glutamine-rich tetratricopeptide
repeat proteins (SGT) which interact with both HSP70 and HSP90 chaperones. An atypical SGT homolog is found in the L. donovani genome, encoding a protein lacking the C-terminal glutamine-rich region, normally typical for SGT family members. The gene
is expressed constitutively during the life cycle and is essential for survival and/or growth of the parasites. LdSGT forms
large, stable complexes that also include another putative co-chaperone, HSC70 interacting protein (HIP). The gene product
forms cytoplasmic clusters, matching the subcellular distribution of HIP and partly that of the major cytoplasmic chaperones,
HSP70 and HSP90, reflecting a direct molecular interaction with both chaperones. 相似文献
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Maqsud Hossain Sharon A Egan Tracey Coffey Philip N Ward Ray Wilson James A Leigh Richard D Emes 《BMC genomics》2015,16(1)
Background
Streptococcus uberis, a Gram-positive, catalase-negative member of the family Streptococcaceae is an important environmental pathogen responsible for a significant proportion of subclinical and clinical bovine intramammary infections. Currently, the genome of only a single reference strain (0140J) has been described. Here we present a comparative analysis of complete draft genome sequences of an additional twelve S. uberis strains.Results
Pan and core genome analysis revealed the core genome common to all strains to be 1,550 genes in 1,509 orthologous clusters, complemented by 115-246 accessory genes present in one or more S. uberis strains but absent in the reference strain 0140J. Most of the previously predicted virulent genes were present in the core genome of all 13 strains but gene gain/loss was observed between the isolates in CDS associated with clustered regularly interspaced short palindromic repeats (CRISPRs), prophage and bacteriocin production. Experimental challenge experiments confirmed strain EF20 as non-virulent; only able to infect in a transient manner that did not result in clinical mastitis. Comparison of the genome sequence of EF20 with the validated virulent strain 0140J identified genes associated with virulence, however these did not relate clearly with clinical/non-clinical status of infection.Conclusion
The gain/loss of mobile genetic elements such as CRISPRs and prophage are a potential driving force for evolutionary change. This first “whole-genome” comparison of strains isolated from clinical vs non-clinical intramammary infections including the type virulent vs non-virulent strains did not identify simple gene gain/loss rules that readily explain, or be confidently associated with, differences in virulence. This suggests that a more complex dynamic determines infection potential and clinical outcome not simply gene content.Electronic supplementary material
The online version of this article (doi:10.1186/s12864-015-1512-6) contains supplementary material, which is available to authorized users. 相似文献4.
Pseudomonas syringae pv. tabaci causes wildfire disease in tobacco plants. The hrp pathogenicity island (hrp PAI) of P. syringae pv. tabaci encodes a type III secretion system (TTSS) and its regulatory system, which are required for pathogenesis in plants.
Three important regulatory proteins-HrpR, HrpS, and HrpL-have been identified to activate hrp PAI gene expression. The bacterial Lon protease regulates the expression of various genes. To investigate the regulatory
mechanism of the Lon protease in P. syringae pv. tabaci 11528, we cloned the lon gene, and then a Δlon mutant was generated by allelic exchange. lon mutants showed increased UV sensitivity, which is a typical feature of such mutants. The Δlon mutant produced higher levels of tabtoxin than the wild-type. The lacZ gene was fused with hrpA promoter and activity of β-galactosidase was measured in hrp-repressing and hrp-inducing media. The Lon protease functioned as a negative regulator of hrp PAI under hrp-repressing conditions. We found that strains with lon disruption elicited the host defense system more rapidly and strongly
than the wild-type strain, suggesting that the Lon protease is essential for systemic pathogenesis. 相似文献
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Sanjay MK Srideshikan SM Vanishree VL Usha MS Raj AP Gaddad SM Shivannavar CT 《Indian journal of microbiology》2011,51(3):326-331
Superoxide dismutase has been discovered within the periplasm of several Gram-negative pathogens. We studied the Cu,Zn-SOD
enzyme in Escherichia coli isolated from clinical samples (stool samples) collected from patients suffering from diarrhea. Antibiogram studies of the
isolates were carried out to determine the sensitive and resistant strains. The metal co-factor present in the enzyme was
confirmed by running samples in native gels and inhibiting with 2 mM potassium cyanide. A 519 bp sodC gene was amplified from resistant and sensitive strains of Escherichia coli. Cloning and sequencing of the sodC gene indicated variation in the protein and amino acid sequences of sensitive and resistant isolates. The presence of sodC in highly resistant Escherichia coli isolates from diarrheal patients indicates that sodC may play role in enhancing the pathogenicity by protecting cells from exogenous sources of superoxide, such as the oxidative
burst of phagocytes. The presence of SodC could be one of the factors for bacterial virulence. 相似文献
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The marine-estuarine bacterium Vibrio harveyi is an important pathogen of invertebrates, most significantly, the larvae of commercially important shrimp Penaeus monodon. In this study, we analyzed V. harveyi isolated from shrimp hatchery environments for understanding the distribution of putative virulence genes and antimicrobial
drug resistance. The putative genes targeted for PCR detection included four reversible toxin (Rtx)/hemolysin genes, a gene
encoding homologue of Vibrio
cholerae zonula occludens toxin (Zot) and a hemolysin-coregulated protein gene (hcp) by polymerase chain reaction (PCR). Of the four putative reversible toxin genes, vhh-1 was detected in 31% of the isolates, vhh-2 in 46%, vhh-3 in 23% and vhh-4 was detected in 27% of the isolates. A zot-like sequence of bacteriophage f237 was present in 15%, while hcp sequence was detected in 48% of the isolates. The antimicrobial susceptibility test revealed resistance to several groups
of antibiotics including β-lactams, cephalosporins, macrolides, quinolones, nitrofurantoin and tetracycline. 相似文献
9.
Water samples of the river Narmada from the source to the mouth were analyzed for the presence of shigellae and the Shigella isolates from 180 water samples were characterized by biotyping, serotyping and molecular typing. Out of all the 40 isolates,
23 were identified as S. flexneri, 10 as S. sonnei and 7 as S. dysenteriae. Serotyping was found to be the better identification method than biotyping. In the present investigation, amplified ribosomal
DNA restriction analysis (ARDRA) with a probe complementary to 16S rRNA was performed. Repeated ARDRA analysis established
the similarities between the isolates and thus suggested ARDRA as authentic and precise detection protocol. The isolates were
also analyzed for the presence of virulence genes including ipaBCD, ipaH and stx1. All the 40 isolates of Shigella were found to be positive for the ipaH gene. The plasmid encoded invasion-associated genes ipaBCD were present only in S. flexneri and the stx1 gene was found only in S. dysenteriae. This study demonstrated the existence of Shigella in the river Narmada and the dispersion of different virulence genes among the isolates, which appear to constitute an environmental
reservoir of Shigella-specific virulence genes. 相似文献
10.
The ATPases associated with various cellular activities (AAA) proteins are widespread in living organisms. Some of the AAA-type
ATPases possess metalloprotease activities. Other members constitute the 26S proteasome complexes. In recent years, a few
AAA members have been implicated in vesicle-mediated secretion, membrane fusion, cellular organelle biogenesis, and hypersensitive
responses (HR) in plants. However, the physiological roles and biochemical activities of plant AAA proteins have not yet been
defined at the molecular level, and regulatory mechanisms underlying their functions are largely unknown. In this study, we
showed that overexpression of an Arabidopsis gene encoding a mitochondrial AAA protein, ATPase-in-Seed-Development (ASD), induces morphological and anatomical defects
in seed maturation. The ASD gene is expressed at a high level during the seed maturation process and in mature seeds but is repressed rapidly in germinating
seeds. Transgenic plants overexpressing the ASD gene are morphologically normal. However, seed formation is severely disrupted in the transgenic plants. The ASD gene is
induced by abiotic stresses, such as low temperatures and high salinity, in an abscisic acid (ABA)-dependent manner. The ASD
protein possesses ATPase activity and is localized into the mitochondria. Our observations suggest that ASD may play a role
in seed maturation by influencing mitochondrial function under abiotic stress. 相似文献
11.
In Drosophila, the gustatory receptor (Gr) gene family contains 60 family members that encode 68 proteins through alternative splicing. Some gustatory receptors (Grs)
are involved in the sensing of sugars, bitter substrates, CO2, pheromones, and light. Here, we systematically examined the expression of all 68 Grs in abdominal neurons which project
to the abdominal ganglion of the central nervous system using the GAL4/UAS system. Gr gene expression patterns have been successfully analyzed in previous studies by using the GAL4/UAS system to drive reporter gene expression. Interestingly, 21 Gr-GAL4 drivers showed abdominal ganglion projection, and 18 of these 21 Gr-GAL4 drivers labeled multidendritic neurons of the abdominal wall. 4 drivers also labeled neuronal processes innervating the reproductive
organs. The peripheral expression of Gr-GAL4 drivers in abdominal multidendritic neurons or neurons innervating the reproductive organs suggests that these Grs have atypical
sensory functions in these organs not limited to conventional taste sensing. 相似文献
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Vipin Chandra Kalia Ravi Kumar Prasun Kumar Shikha Koul 《Indian journal of microbiology》2016,56(1):46-58
The use of rrs (16S rRNA) gene is widely regarded as the “gold standard” for identifying bacteria and determining their phylogenetic relationships. Nevertheless, multiple copies of this gene in a genome is likely to give an overestimation of the bacterial diversity. In each of the 50 Streptococcus genomes (16 species, 50 strains), 4–7 copies of rrs are present. The nucleotide sequences of these rrs genes show high similarity within and among genomes, which did not allow unambiguous identification. A genome-wide search revealed the presence of 27 gene sequences common to all the Streptococcus species. Digestion of these 27 gene sequences with 10 type II restriction endonucleases (REs) showed that unique RE digestion in purH gene is sufficient for clear cut identification of 30 genomes belonging to 16 species. Additional gene-RE combinations allowed identification of another 15 strains belonging to S. pneumoniae, S. pyogenes, and S. suis. For the rest 5 strains, a combination of 2 genes was required for identifying them. The proposed strategy is likely to prove helpful in proper detection of pathogens like Streptococcus.
Electronic supplementary material
The online version of this article (doi:10.1007/s12088-015-0561-5) contains supplementary material, which is available to authorized users. 相似文献14.
Korean salamanders of the genus Hynobius are currently classified into 3 species, H. leechii, H. quelpaertensis, and H. yangi. To investigate the phylogenetic relationship of these species, we analyzed the partial sequence of mitochondrial cytochrome
b gene (907 bp) of 197 specimens from 43 regions in South Korea. Of these specimens, 93 were additionally examined with 12S
rRNA (799 bp). Based on the partial sequence of the mitochondrial cytochrome b gene and 12S rRNA, 89 and 36 haplotypes were
defined, respectively, consisting of six subclades (H. leechii, H. quelpaertensis, H. yangi, HC1, HC2, and HC3). Among these subclades, the three subclades (HC1, HC2, and HC3) were clearly separated from the 3 previously
reported species in the genus Hynobius. Pairwise sequence divergence between the six subclades ranged from 6.3 to 11.2% in cytochrome b gene and 2.0 to 4.3% in 12S rRNA. These results indicate there may be more divergent populations than the three currently
described. Moreover, the estimation of divergence time revealed that the Hynobius species in South Korea diverged during the
Miocene epoch, approximately 9 — 5 MYA. In addition, we confirmed the distribution of the three known species (H. leechii, H. quelpaertensis, and H. yangi) and determined the distributions of new, distinct groups (or subclades; HC1, HC1, and HC3). To more accurately establish
the taxonomic status and population structure, further genetic, morphological, and ecological studies will be needed. 相似文献
15.
Wei Zhang Hideo Tsurushima Ayako Oyane Yushin Yazaki Yu Sogo Atsuo Ito Akira Matsumura 《Journal of biomedical science》2011,18(1):62
Background
Safe and efficient gene transfer systems are needed for tissue engineering. We have developed an apatite composite layer including the bone morphogenetic protein-2 (BMP-2) gene and fibronectin (FB), and we evaluated its ability to induce bone formation. 相似文献16.
The development and rapid spread of chloroquine resistance (CQR) in
Plasmodium falciparum have triggered the identification of
several genetic target(s) in the P. falciparum genome. In
particular, mutations in the Pfcrt gene, specifically, K76T and
mutations in three other amino acids in the region adjoining K76 (residues 72, 74, 75
and 76), are considered to be highly related to CQR. These various mutations form
several different haplotypes and Pfcrt gene polymorphisms and the
global distribution of the different CQR- Pfcrt haplotypes in
endemic and non-endemic regions of P. falciparum malaria have been
the subject of extensive study. Despite the fact that the Pfcrt gene
is considered to be the primary CQR gene in P. falciparum , several
studies have suggested that this may not be the case. Furthermore, there is a poor
correlation between the evolutionary implications of the Pfcrt
haplotypes and the inferred migration of CQR P. falciparum based on
CQR epidemiological surveillance data. The present paper aims to clarify the existing
knowledge on the genetic basis of the different CQR- Pfcrt
haplotypes that are prevalent in worldwide populations based on the published
literature and to analyse the data to generate hypotheses on the genetics and
evolution of CQR malaria. 相似文献
17.
Kim SN Shim HP Jeon BN Choi WI Hur MW Girton JR Kim SH Jeon SH 《Molecules and cells》2011,32(6):549-554
Polycomb group (PcG) proteins maintain the spatial expression patterns of genes that are involved in cell-fate specification
along the anterior-posterior (A/P) axis. This repression requires cis-acting silencers, which are called PcG response elements (PREs). One of the PcG proteins, Pleiohomeotic (Pho), which has
a zinc finger DNA binding protein, plays a critical role in recruiting other PcG proteins to bind to PREs. In this study,
we characterized the effects of a pho mutation on embryonic segmentation. pho maternal mutant embryos showed various segmental defects including pair-rule gene mutant patterns. Our results indicated
that engrailed and even-skipped genes were misexpressed in pho mutant embryos, which caused embryonic segment defects. 相似文献
18.
Urinary tract infection (UTI) with E. coli (UPEC) is one of the most common bacterial infections among human beings. In addition to the host predisposing factors, genes
are also proposed to have an important role in the occurrence of UTIs. This study investigated the distribution of three pathogenic
genes including aggR, aap and aatA among UPEC infected samples and their linkage with stbA, the essential gene for maintaining of pAA plasmid. A total of 244 samples were collected from patients with UTIs through
clinical laboratories located in western side of Tehran (Iran) during years 2008–2009. E. coli isolation was performed according to standard laboratory methods. DNAs were extracted from samples using Boiling method,
and the presence of aap, aggR, aatA and stbA genes were investigated by PCR. No pathogenic genes (aap, aggR, aatA) were found in 104 out of 244 UPEC samples, while 14 of them were carrying stbA gene. Out of 140 UPEC samples with pathogenic genes, 94 (46.6%) were carrying aap gene, 52 (23%) aggR gene, and 80 (35.4%) aatA gene. A total of 18 samples were also carrying all pathogenic genes together. Moreover, 44 out of 144 samples were carrying
stbA gene. The results obtained by this study showed that the aggR, aap and aatA pathogenic genes have different existence patterns in different E. coli strains that infect different organs. Our study also showed that these three plasmid genes in EAEC strains are able to transpose
in the genome and change their level of linkage with pAA plasmid essential gene stbA. Meanwhile, this study confirmed that aggR, aap and aatA genes are not specific to only EAEC strains. 相似文献
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