scholarly journals The Role of Cellulose and O-Antigen Capsule in the Colonization of Plants by Salmonella enterica

2007 ◽  
Vol 20 (9) ◽  
pp. 1083-1091 ◽  
Author(s):  
Jeri D. Barak ◽  
Courtney E. Jahn ◽  
Deanna L. Gibson ◽  
Amy O. Charkowski
Keyword(s):  
Extracellular Matrix ◽  
Salmonella Enterica ◽  
Cellulose Synthesis ◽  
Salmonella Spp ◽  
O Antigen ◽  
Promoter Probe ◽  
Polymerase Chain ◽  
Capsule Assembly ◽  
Alfalfa Sprouts

Numerous salmonellosis outbreaks have been associated with vegetables, in particular sprouted seed. Thin aggregative fimbriae (Tafi), a component of the extracellular matrix responsible for multicellular behavior, are important for Salmonella enterica attachment and colonization of plants. Here, we demonstrate that the other surface polymers composing the extracellular matrix, cellulose, and O-antigen capsule also play a role in colonization of plants. Mutations in bacterial cellulose synthesis (bcsA) and O-antigen capsule assembly and translocation (yihO) reduced the ability to attach to and colonize alfalfa sprouts. A colanic acid mutant was unaffected in plant attachment or colonization. Tafi, cellulose synthesis, and O-antigen capsule, all of which contribute to attachment and colonization of plants, are regulated by AgfD, suggesting that AgfD is a key regulator for survival outside of hosts of Salmonella spp. The cellulose biosynthesis regulator adrA mutant was not affected in the ability to attach to or colonize plants; however, promoter probe assays revealed expression by cells attached to alfalfa sprouts. Furthermore, quantitative reverse-transcriptase polymerase chain reaction revealed differential expression of agfD and adrA between planktonic and plant-attached cells. In addition, there was no correlation among mutants between biofilm formation in culture and attachment to plants. Outside of animal hosts, S. enterica appears to rely on an arsenal of adhesins to persist on plants, which can act as vectors and perpetuate public health concerns.

scholarly journals DETECTION OF VIRULENCE GENES phoP AND phoQ IN Salmonella spp. USING IN SILICO POLYMERASE CHAIN REACTION

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Stalis Norma Ethica ◽  
Hayatun Fuad ◽  
Nur Hidayah ◽  
Sri Sinto Dewi ◽  
Aditya Rahman Ernanto ◽  
...  
Keyword(s):  
In Silico ◽  
Salmonella Enterica ◽  
Virulence Genes ◽  
Gene Detection ◽  
Chain Reaction ◽  
Salmonella Spp ◽  
Detection Tool ◽  
In Silico Study ◽  
Polymerase Chain ◽  
In Silico Pcr

Detection of Salmonella bacteria based on their virulence genes is among essential steps in the eradication of clinical infection by bacteria. In this study, two pair of primers, PhoPF-PhoPR: 5’- CCGCGCAGGAAAAACTCAAA-3’ and 5’-ATCTGTTCCAGCATCACCGG -3’ as well as PhoQF-PhoQR: 5’-AGAGATGATGCGCGTACTGG-3’ and 5’- CAGACGCCCCATGAGAACAT-3’, had been successfully designed using Primer3Plus to detect the presence of phoP and phoQ genes in Salmonella spp. Using genomic DNA of 44 genomic data of Salmonella spp. as templates, PhoPF-PhoPR could produce 520-bp amplicon, while PhoQF-PhoQR could result in 598-bp amplicon. Results of in silico PCR showed that both pairs of primers PhoPF-PhoPR and PhoQF-PhoQR could detect only Salmonella enterica species, and no Salmonella bongori species could be detected based on phoP and phoQ sequences. Both pairs of PhoPF-PhoPR and PhoQF-PhoQR primers were also able to detect the virulence genes in most of the studied subspecies of Salmonella enterica available in silico database unless Arizona subspecies. As conclusion, based on this in silico study, phoP and phoQ genes appeared to be biomarkers for Salmonella enterica species. Both pairs of primers designed in this study has potential to be used as detection tool to differentiate species Salmonella enterica from Salmonella bongori, and also to distinguish S.enterica subsp. enterica from subsp. Arizonae.Keywords: Gene detection, bacterial virulence, phoP, phoQ, Salmonella spp.

scholarly journals The enzyme phosphoglucomutase (Pgm) is required by Salmonella enterica serovar Typhimurium for O-antigen production, resistance to antimicrobial peptides and in vivo fitness

Microbiology ◽  
2009 ◽  
Vol 155 (10) ◽  
pp. 3403-3410 ◽  
Author(s):  
G. K. Paterson ◽  
D. B. Cone ◽  
S. E. Peters ◽  
D. J. Maskell
Keyword(s):  
Antimicrobial Peptides ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Live Attenuated Vaccine ◽  
Antigen Production ◽  
O Antigen ◽  
Serovar Typhimurium

The enzyme phosphoglucomutase (Pgm) catalyses the interconversion of glucose 1-phosphate and glucose 6-phosphate and contributes to glycolysis and the generation of sugar nucleotides for biosynthesis. To assess the role of this enzyme in the biology of the pathogen Salmonella enterica serovar Typhimurium we have characterized a pgm deletion mutant in strain SL1344. Compared to SL1344, SL1344 pgm had impaired growth in vitro, was deficient in the ability to utilize galactose as a carbon source and displayed reduced O-antigen polymer length. The mutant was also more susceptible to antimicrobial peptides and showed decreased fitness in the mouse typhoid model. The in vivo phenotype of SL1344 pgm indicated a role for pgm in the early stages of infection, most likely through deficient O-antigen production. Although pgm mutants in other pathogens have potential as live attenuated vaccine strains, SL1344 pgm was not sufficiently attenuated for such use.

scholarly journals Role of RpoS in Fine-Tuning the Synthesis of Vi Capsular Polysaccharide in Salmonella enterica Serotype Typhi

2006 ◽  
Vol 75 (3) ◽  
pp. 1382-1392 ◽  
Author(s):  
Javier Santander ◽  
Soo-Young Wanda ◽  
Cheryl A. Nickerson ◽  
Roy Curtiss
Keyword(s):  
Salmonella Enterica ◽  
Capsular Polysaccharide ◽  
Fine Tuning ◽  
O Antigen ◽  
Native Promoter ◽  
Regulatory Systems ◽  
Polysaccharide Synthesis ◽  
Clinical Detection ◽  
Vi Capsular Polysaccharide

ABSTRACT Regulation of the synthesis of Vi polysaccharide, a major virulence determinant in Salmonella enterica serotype Typhi, is under the control of two regulatory systems, ompR-envZ and rscB-rscC, which respond to changes in osmolarity. Some serotype Typhi strains exhibit overexpression of Vi polysaccharide, which masks clinical detection of lipopolysaccharide O antigen. This variation in Vi polysaccharide and O antigen display (VW variation) has been observed since the initial studies of serotype Typhi. In this study, we report that rpoS plays a role in this increased expression in Vi polysaccharide. We constructed a variety of isogenic serotype Typhi mutants that differed in their expression levels of RpoS and examined the role of the rpoS product in synthesis of Vi polysaccharide under different osmolarity conditions. Vi polysaccharide synthesis was also examined in serotype Typhi mutants in which the native promoter of the rpoS was replaced by an araCPBAD cassette, so that the expression of rpoS was arabinose dependent. The RpoS− strains showed increased syntheses of Vi polysaccharide, which at low and medium osmolarities masked O antigen detection. In contrast, RpoS+ strains showed lower syntheses of Vi polysaccharide, and an increased detection of O antigen was observed. During exponential growth, when rpoS is unstable or present at low levels, serotype Typhi RpoS+ strains overexpress the Vi polysaccharide at levels comparable to those for RpoS− strains. Our results show that RpoS is another regulator of Vi polysaccharide synthesis and contributes to VW variation in serotype Typhi, which has implications for the development of recombinant attenuated Salmonella vaccines in humans.

scholarly journals Salmonella enterica in semi-aquatic turtles in Colombia

2011 ◽  
Vol 5 (05) ◽  
pp. 361-364 ◽  
Author(s):  
Miryan Margot Sánchez-Jiménez ◽  
Paula Andrea Rincón-Ruiz ◽  
Sara Duque ◽  
María Adelaida Giraldo ◽  
Diber Marcela Ramírez-Monroy ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Salmonella Enterica ◽  
Chain Reaction ◽  
Salmonella Spp ◽  
Wildlife Protection ◽  
Polymerase Chain

Introduction: Turtles can be hosts of Salmonella enterica serovars which can cause disease both in the animals themselves and in people they come into contact with, especially when the turtles are kept as pets. To investigate the prevalence of Salmonella in turtles in Colombia, we studied animals at a wildlife protection centre. The turtles had either been confiscated or donated to the centre. Methodology: Detection of Salmonella spp. was conducted in feces samples using bacteriological cultures and polymerase chain reaction to identify genus and serovar.  Results: By PCR and culture, 30/110 samples (27%) were positive while by PCR alone eight further samples were positive (total of 38/110 (35%) positive). The most common serovar was S. Enteritidis (26/38 (68%) with only one isolate being S. Typhimurium (3%).  Four (11%) samples were positive for both serovars and seven (18%) could only be identified as Salmonella enterica spp. Conclusions: These results show that turtles in Colombia are commonly infected with Salmonella and are a risk for infection to people who come into contact with them.

scholarly journals Salmonella Produces an O-Antigen Capsule Regulated by AgfD and Important for Environmental Persistence

2006 ◽  
Vol 188 (22) ◽  
pp. 7722-7730 ◽  
Author(s):  
D. L. Gibson ◽  
A. P. White ◽  
S. D. Snyder ◽  
S. Martin ◽  
C. Heiss ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Structural Analysis ◽  
Immune Serum ◽  
Extracellular Polysaccharides ◽  
Survival Strategy ◽  
Environmental Persistence ◽  
O Antigen ◽  
Expression Studies ◽  
Carbohydrate Transport ◽  
Capsule Assembly

ABSTRACT In this study, we show that Salmonella produces an O-antigen capsule coregulated with the fimbria- and cellulose-associated extracellular matrix. Structural analysis of purified Salmonella extracellular polysaccharides yielded predominantly a repeating oligosaccharide unit similar to that of Salmonella enterica serovar Enteritidis lipopolysaccharide O antigen with some modifications. Putative carbohydrate transport and regulatory operons important for capsule assembly and translocation, designated yihU-yshA and yihVW, were identified by screening a random transposon library with immune serum generated to the capsule. The absence of capsule was confirmed by generating various isogenic Δyih mutants, where yihQ and yihO were shown to be important in capsule assembly and translocation. Luciferase-based expression studies showed that AgfD regulates the yih operons in coordination with extracellular matrix genes coding for thin aggregative fimbriae and cellulose. Although the capsule did not appear to be important for multicellular behavior, we demonstrate that it was important for survival during desiccation stress. Since the yih genes are conserved in salmonellae and the O-antigen capsule was important for environmental persistence, the formation of this surface structure may represent a conserved survival strategy.

The PmrA/PmrB regulatory system controls the expression of the wzzfepE gene involved in the O-antigen synthesis of Salmonella enterica serovar Typhimurium

Microbiology ◽  
2011 ◽  
Vol 157 (9) ◽  
pp. 2515-2521 ◽  
Author(s):  
María de las Mercedes Pescaretti ◽  
Fabián E. López ◽  
Roberto D. Morero ◽  
Mónica A. Delgado
Keyword(s):  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Regulatory System ◽  
Polymyxin B ◽  
Degree Of Polymerization ◽  
O Antigen ◽  
Functional Differences ◽  
Serovar Typhimurium ◽  
Direct Binding

The degree of polymerization of O-antigen from Salmonella enterica serovar Typhimurium is controlled by the products of the wzzs t and wzzfepE genes. In the present study we investigated the role of the PmrA/PmrB regulatory system in wzzfepE transcription. We report that the direct binding of the PmrA regulator to a specific promoter site induces the expression of the wzzfepE gene. This effect increases the amount of very long (VL) O-antigen, which is required for the resistance of Salmonella to serum human complement and polymyxin B, and for the replication of the bacteria within macrophages. The results obtained here highlight functional differences between WzzfepE and Wzzst, although the genes for both proteins are regulated in a PmrA-dependent way.

Effects of angiotensin II on cultured rat renomedullary interstitial cells are mediated by AT1A receptors

1996 ◽  
Vol 271 (5) ◽  
pp. F1020-F1028 ◽  
Author(s):  
C. Maric ◽  
G. P. Aldred ◽  
A. M. Antoine ◽  
R. G. Dean ◽  
E. Eitle ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Angiotensin Ii ◽  
Interstitial Cells ◽  
Receptor Subtype ◽  
Ang Ii ◽  
Sprague Dawley ◽  
Vasoactive Peptides ◽  
Polymerase Chain ◽  
Second Messenger Pathways

Renomedullary interstitial cells (RMICs) are prominent in the inner medullary interstitium and have binding sites for several vasoactive agents, including angiotensin II (ANG II). Although the functional role of RMICs remains largely unknown, it is likely that the interaction between RMICs and vasoactive peptides is important in the regulation of renal function. The current investigation characterizes the cellular responses following treatment of RMICs with ANG II. Studies were performed on RMICs isolated from Sprague-Dawley rat kidneys. 125I-labeled [Sar1,Ile8]ANG II specifically bound to RMICs at sites determined by reverse transcription-polymerase chain reaction to be of the AT1A subtype. ANG II (10(-6) and 10(-10) M) had no effect on either basal or forskolin-stimulated adenosine 3',5'-cyclic monophosphate accumulation in RMICs but increased intracellular inositol 1,4,5-trisphosphate concentration after 10 s and intracellular calcium concentration after 18 s. For RMICs plated at low densities, ANG II (10(-6) M) induced an increase in [3H]thymidine incorporation, mediated through the AT1-receptor subtype. For RMICs plated at high densities, ANG II (10(-6) M) induced an increase in extracellular matrix synthesis as detected by trans-35S incorporation, an effect also mediated by AT1 receptors. We conclude that ANG II AT1A receptors on cultured RMICs are coupled to intracellular second messenger pathways leading to hyperplasia and synthesis of extracellular matrix.

Extracellular matrix: the gatekeeper of tumor angiogenesis

2019 ◽  
Vol 47 (5) ◽  
pp. 1543-1555 ◽  
Author(s):  
Maurizio Mongiat ◽  
Simone Buraschi ◽  
Eva Andreuzzi ◽  
Thomas Neill ◽  
Renato V. Iozzo
Keyword(s):  
Extracellular Matrix ◽  
Tumor Angiogenesis ◽  
Signaling Cascades ◽  
Cancer Growth ◽  
Cell Behavior ◽  
Metastatic Progression ◽  
Surface Receptors ◽  
The Matrix ◽  
Multiple Signaling

Abstract The extracellular matrix is a network of secreted macromolecules that provides a harmonious meshwork for the growth and homeostatic development of organisms. It conveys multiple signaling cascades affecting specific surface receptors that impact cell behavior. During cancer growth, this bioactive meshwork is remodeled and enriched in newly formed blood vessels, which provide nutrients and oxygen to the growing tumor cells. Remodeling of the tumor microenvironment leads to the formation of bioactive fragments that may have a distinct function from their parent molecules, and the balance among these factors directly influence cell viability and metastatic progression. Indeed, the matrix acts as a gatekeeper by regulating the access of cancer cells to nutrients. Here, we will critically evaluate the role of selected matrix constituents in regulating tumor angiogenesis and provide up-to-date information concerning their primary mechanisms of action.

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