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1.
Background
The type III secretion system (TTSS) is an important virulence determinant of Gram-negative bacterial pathogens. It enables the injection of effector proteins into the cytosol of eukaryotic cells. These effectors ultimately manipulate the cellular functions of the infected organism. Salmonella enterica serovar Typhimurium encodes two virulence associated TTSSs encoded by the Salmonella Pathogenicity Islands (SPI) 1 and 2 that are required for the intestinal and systemic phases of the infection, respectively. However, recent studies suggest that the roles of these TTSSs are not restricted to these compartments. The regulation of TTSSs in Salmonella is very complex with several regulators operating to activate or to repress expression depending on the environmental conditions. 相似文献2.
Salmonella causes the majority of infections in humans and homeothermic animals. This article describes a specific polymerase chain
reaction (PCR) method developed for a rapid identification of Salmonella. A gyrB-targeted species-specific primer pair, S-P-for (5′-GGT GGT TTC CGT AAA AGT A-3′) and S-P-rev (5′-GAA TCG CCT GGT TCT TGC-3′),
was successfully designed. PCR with all the Salmonella strains produced a 366- bp DNA fragment that was absent from all the non-Salmonella strains tested. The detection limit of the PCR was 0.01 ng with genomic DNA or 3.2 cells per assay. Good specificity was
also demonstrated by fecal samples, from which only the gyrB gene of Salmonella was amplified. Using the culture-PCR method, 27 isolates on Salmonella-Shigella (SS) medium were rapidly identified as Salmonella, which was confirmed by the sequencing of the gyrB gene. 相似文献
3.
Jiu-Cun Wang Syeling Lai Xinjian Guo Xuefeng Zhang Benoit de Crombrugghe Sonali Sonnylal Frank C Arnett Xiaodong Zhou 《Arthritis research & therapy》2010,12(2):R60
Introduction
SPARC is a matricellular protein, which, along with other extracellular matrix components including collagens, is commonly over-expressed in fibrotic diseases. The purpose of this study was to examine whether inhibition of SPARC can regulate collagen expression in vitro and in vivo, and subsequently attenuate fibrotic stimulation by bleomycin in mouse skin and lungs. 相似文献4.
Chai-Hoon Khoo Yoke-Kqueen Cheah Learn-Han Lee Jiun-Horng Sim Noorzaleha Awang Salleh Shiran Mohd Sidik Son Radu Sabrina Sukardi 《Antonie van Leeuwenhoek》2009,96(4):441-457
The increased occurrence of Salmonella occurrence in local indigenous vegetables and poultry meat can be a potential health hazards. This study is aimed to detect
the prevalence of twenty different virulence factors among Salmonella enterica strains isolated from poultry and local indigenous vegetables in Malaysia via an optimized, rapid and specific multiplex
PCR assay. The assay encompasses a total of 19 Salmonella pathogenicity islands genes and a quorum sensing gene (sdiA) in three multiplex reaction sets. A total of 114 Salmonella
enterica isolates belonging to 38 different serovars were tested. Each isolate in under this study was found to possess up to 70%
of the virulence genes tested and exhibited variable pathogenicity gene patterns. Reproducibility of the multiplex PCR assay
was found to be 100% and the detection limit of the optimized multiplex PCR was tested with lowest detectable concentration
of DNA 0.8 pg μl−1. This study demonstrated various Salmonella pathogenicity island virulence gene patterns even within the same serovar. This sets of multiplex PCR system provide a fast
and reliable typing approach based on Salmonella pathogenicity islands, thus enabling an effective monitoring of emerging pathogenic Salmonella strains as an additional tool in Salmonella surveillance studies. 相似文献
5.
Masaaki Urata Rei Iwata Kenichi Noda Yuji Murakami Akio Kuroda 《Biotechnology letters》2009,31(5):737-741
ATP-based bioluminescence using mutant firefly luciferase was combined with an immunochromatographic lateral flow test strip
assay for Salmonella enteritidis detection. In this combination method, the Salmonella-antibody–gold complex captured at the test line on the test strip was lysed by heat-treatment, and the ATP released from
the cells was measured using mutant luciferase. This method resulted in approximately 1,000 times higher sensitivity in the
detection of Salmonella (i.e. 103 c.f.u./ml) compared to immunochromatographic lateral flow assay. 相似文献
6.
Rakesh Kumar P. K. Surendran Nirmala Thampuran 《World journal of microbiology & biotechnology》2008,24(5):627-631
A rapid and sensitive 8-h PCR assay has been developed for detection of Salmonella serovars in seafood. A total of 110 fresh and raw seafood samples were analysed for the presence of Salmonella using different enrichment periods prior to PCR assay. Seafood samples included in this study were fish, shrimps, mussels,
crabs, edible oysters, and clams, collected from local fish markets in Cochin (India). The assay was performed with a Salmonella-specific 284 bp invA gene amplicon. Specificity and sensitivity of the assay were ascertained with seafoods spiked with viable Salmonella cells to a level of 106 to 2 CFU per 25 g. Detection efficiency of the assay increased with increasing enrichment period for seafood, and 33.6% of
seafood samples were found positive for Salmonella by 8-h PCR assay. Detection limit for the 8-h PCR assay showed visible 284 bp amplicon from seafood homogenates spiked with 2 CFU per 25 g.
Seafood samples spiked with different Salmonella serovars, namely Salmonella typhi, Salmonella typhimurium, Salmonella enteritidis, Salmonella mbandka, Salmonella bareilly, and Salmonella weltevreden, were detected, confirming this technique would be ideal for detection of the Salmonella serovars prevalent in seafood. This study also covered inhibition by the seafood matrix and the detection limit for dead
Salmonella cells during the PCR assay. There was no visible inhibition of this Salmonella PCR assay by seafood matrices. The detection limit for dead Salmonella cells by 8-h PCR assay was 2 × 103 CFU per 25 g seafood. The data indicated that dead cells of Salmonella in naturally contaminated seafood samples do not interfere with the assay resulting in false positives. 相似文献
7.
Mohammad Jahangir Alam David Renter Ethel Taylor Diana Mina Rodney Moxley David Smith 《Current microbiology》2009,58(4):354-359
Salmonella enterica in cattle production systems may be associated with important human and animal disease issues. However, tremendous diversity
exists among Salmonella recovered, and more information is needed about strains of greatest potential health concern, particularly those that are
multidrug resistant (MDR). By characterizing Salmonella isolates from commercial feedlot pens, this study aimed to evaluate the strain diversity and prevalence of MDR Salmonella from different types of composite pen samples. Antimicrobial susceptibility profiles, serotype, and presence or absence of
the integron-encoded intI1 gene were determined for 530 Salmonella isolates recovered using composite rope (n = 335), feces (n = 59), and water (n = 136) samples from 21 pens in 3 feedlots. The study investigated only pens with available isolates from multiple sample
types. Most isolates (83.0%) of the 19 Salmonella serotypes identified were susceptible or intermediately susceptible to all the antimicrobials evaluated. Resistance to sulfisoxazole
(14.9%), streptomycin (3.8%), and tetracycline (3.6%) were the most common. None of the isolates tested positive for a class
1 integron, and only 2.5% were resistant to multiple antimicrobials. All the MDR isolates, namely, serotypes Uganda (n = 9), Typhimurium (n = 2), and Give (n = 2), were resistant to at least five antimicrobials. Most MDR isolates (n = 11) were from two pens during 1 week within one feedlot. Overall, many Salmonella isolates collected within a pen were similar in terms of serotype and antimicrobial susceptibility regardless of sample type.
However, MDR Salmonella and rare serotypes were not recovered frequently enough to suggest a general strategy for appropriate composite sampling
of feedlot cattle populations for Salmonella detection and monitoring. 相似文献
8.
Background
Salmonella enterica is a facultative intracellular pathogen that replicates within a membrane-bound compartment termed Salmonella containing vacuole (SCV). The biogenesis of SCV requires Salmonella type III protein secretion/translocation system and their effector proteins which are translocated into host cells to exploit the vesicle trafficking pathways. SseF is one of these effectors required for SCV formation and Intracellular Salmonella replication through unknown mechanisms. 相似文献9.
Background
Salmonella enterica serotype Enteritidis (SE) is considered to be one of the most potent pathogenic Salmonella serotypes causing food-borne disease in humans. Since a live bacterial vaccine based on surface display of antigens has many advantages over traditional vaccines, we have studied the surface display of the SE antigenic proteins, H:gm and SefA in Escherichia coli by the β-autotransporter system, AIDA. This procedure was compared to protein translocation in Staphylococcus carnosus, using a staphylococci hybrid vector earlier developed for surface display of other vaccine epitopes. 相似文献10.
Yanmei Zhang Fei Li Dongchang Sun Jiangdong Liu Na Liu Qixing Yu 《Molecular biology reports》2011,38(1):275-282
R-spondin1 (RSPO1) is a potential female-determining gene in human (Homo sapiens) and mouse (Mus musculus). Its differential expression in these mammals is correlated with signaling for sex determination. As a way of studying sex
determination in fish we cloned and analyzed a RSPO1 gene in zebrafish (Danio rerio). Using real-time PCR, we observed that RSPO1 is expressed more strongly in ovaries than in testes, suggesting that RSPO1 may have a role in gonad differentiation. High RSPO1 expression was detected in some non-gonadal organs like muscle and kidneys. In situ hybridization results demonstrate that
RSPO1 is expressed in premature germ cells, in oogonia and primary oocytes in ovaries and in spermatogonia and spermatocytes in
testes. It is also expressed in gonad somatic cells during gonadal development: in granulosa cells and theca cells of early
and late cortical-alveolar stage follicles in ovaries, and in Leydig cells in testes. This differential expression may indicate
that RSPO1 has a role(s) in zebrafish gonad development and differentiation. By fusing zebrafish RSPO1 with a green fluorescent protein gene, we found that RSPO1 is located in the cytosol and Golgi apparatus but not the nucleus
of fish epithelioma papulosum cyprinid (EPC) cells. These preliminary findings suggest some aspects of RSPO1 like differential
expression linked to sex determination may be conserved in fish while other aspects like subcellular localization differ from
the mammalian RSPO1. 相似文献
11.
12.
Karen A. Silverman Revati A. Koratkar Linda D. Siracusa Arthur M. Buchberg 《Mammalian genome》2003,14(2):119-129
Abstract
We recently identified the Modifier of Min 2 (Mom2) locus. Mom2 is a new modifier of intestinal tumorigenesis that resulted from a spontaneous mutation in a B6 Apc
Min/+ mouse. The presence of one resistant Mom2
R allele results in a significant reduction in small intestinal polyp number and colon polyp incidence in Apc
Min/+ mice. Through linkage analysis, we previously localized Mom2 to a 14-cM region on mouse Chromosome (Chr) 18, distal to the Apc gene. This region is syntenic with human Chr 18q, which frequently undergoes loss of heterozygosity (LOH) in several human cancers, including colorectal cancer. Residing in this region are the Madh2 and Madh4 genes, which have both been implicated in human colorectal cancer. Based on meiotic recombinations within the Mom2 region in the derivation of our congenic animals, we have narrowed the location of the Mom2 locus and excluded Madh2, Madh4, and Madh7, as well as Mbd1, Mbd2, Dcc, and Tcf4, as candidates for the Mom2 gene. 相似文献
13.
14.
Luciana Delgado-Benarroch Barry Causier Julia Weiss Marcos Egea-Cortines 《Planta》2009,229(6):1219-1229
Control of organ size is the product of coordinated cell division and expansion. In plants where one of these pathways is
perturbed, organ size is often unaffected as compensation mechanisms are brought into play. The number of founder cells in
organ primordia, dividing cells, and the period of cell proliferation determine cell number in lateral organs. We have identified
the Antirrhinum FORMOSA (FO) gene as a specific regulator of floral size. Analysis of cell size and number in the fo mutant, which has increased flower size, indicates that FO is an organ-specific inhibitor of cell division and activator of cell expansion. Increased cell number in fo floral organs correlated with upregulation of genes involved in the cell cycle. In Arabidopsis the AINTEGUMENTA (ANT) gene promotes cell division. In the fo mutant increased cell number also correlates with upregulation of an Antirrhinum ANT-like gene (Am-ANT) in inflorescences that is very closely related to ANT and shares a similar expression pattern, suggesting that they may be functional equivalents. Increased cell proliferation
is thought to be compensated for by reduced cell expansion to maintain organ size. In Arabidopsis petal cell expansion is inhibited by the BIGPETAL (BPE) gene, and in the fo mutant reduced cell size corresponded to upregulation of an Antirrhinum BPE-like gene (Am-BPE). Our data suggest that FO inhibits cell proliferation by negatively regulating Am-ANT, and acts upstream of Am-BPE to coordinate floral organ size. This demonstrates that organ size is modulated by the organ-specific control of both general
and local gene networks.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
15.
16.
Salmonella enterica is divided into four subspecies containing a large number of different serovars, several of which are important zoonotic
pathogens and some show a high degree of host specificity or host preference. We compare 45 sequenced S. enterica genomes that are publicly available (22 complete and 23 draft genome sequences). Of these, 35 were found to be of sufficiently
good quality to allow a detailed analysis, along with two Escherichia coli strains (K-12 substr. DH10B and the avian pathogenic E. coli (APEC O1) strain). All genomes were subjected to standardized gene finding, and the core and pan-genome of Salmonella were estimated to be around 2,800 and 10,000 gene families, respectively. The constructed pan-genomic dendrograms suggest
that gene content is often, but not uniformly correlated to serotype. Any given Salmonella strain has a large stable core, whilst there is an abundance of accessory genes, including the Salmonella pathogenicity islands (SPIs), transposable elements, phages, and plasmid DNA. We visualize conservation in the genomes in
relation to chromosomal location and DNA structural features and find that variation in gene content is localized in a selection
of variable genomic regions or islands. These include the SPIs but also encompass phage insertion sites and transposable elements.
The islands were typically well conserved in several, but not all, isolates—a difference which may have implications in, e.g.,
host specificity. 相似文献
17.
Technology for monitoring in vivo microRNA (miRNA) activity is extremely important for elucidating miRNA biology. However, in vivo studies of miRNA have been hampered by the lack of a convenient approach to reliably reflect real-time functional changes
in miRNAs. Sensors for miRNA were developed by adding miRNA target sequences to the 3′-untranslated region of Gaussia princeps luciferase (Gluc) mRNA. These sensors were then evaluated in vitro and in vivo by measuring Gluc activity in cell supernatants and in peripheral blood. Sensors driven by the CMV promoter were effective
for monitoring miR-122 in living cells, but not for the long-term monitoring of miR-122 or miR-142 in mouse liver because
of CMV-promoter silencing. Replacing the CMV promoter with a CAG promoter rendered these sensors effective for the long-term
monitoring of relevant liver miRNA activities. We subsequently used the CAG-promoter-based sensor for the long-term monitoring
of endogenous liver miR-122, miR142 and miR-34a activities, as well as for exogenous miR-34a activity. Our study demonstrates
that real-time in vivo activities of miRNAs can be continuously and conveniently detected in mouse liver using the sensors that we have developed. 相似文献
18.
Porteen Kannan Mahesh Dharne Allen Smith Jeffrey Karns Arvind A. Bhagwat 《Current microbiology》2009,59(6):641-645
19.
Salmonella Typhimurium contains 13 operons coding for fimbriae with unique binding specificities to host epithelial surfaces. stj operon is only detected in S. Typhimurium genome suggesting that Stj fimbria may effect serovarspecific virulence characteristics. In this study, the
role of stj fimbrial operon in the long-term persistence of S. Typhimurium was identified by competitive infection experiment in genetically resistant mouse (CBA) model system. Knock-out
mutation of stjA (major subunit of the Stj fimbria) gene reduced recovery of S. Typhimurium from fecal samples and its colonization to spleen, cecum and mesenteric lymph nodes over a 34-day time period
(p < 0.05). This data indicate that stj fimbrial operon has a role in long-term intestinal persistence of S. Typhimurium in CBA mice. 相似文献
20.