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1.
《Phytomedicine》2014,21(3):286-289
Resveratrol, a phytochemical commonly found in the skin of grapes and berries, was tested for its biofilm inhibitory activity against Vibrio cholerae. Biofilm inhibition was assessed using crystal violet assay. MTT assay was performed to check the viability of the treated bacterial cells and the biofilm architecture was analysed using confocal laser scanning microscopy. The possible target of the compound was determined by docking analysis. Results showed that subinhibitory concentrations of the compound could significantly inhibit biofilm formation in V. cholerae in a concentration-dependent manner. AphB was found to be the putative target of resveratrol using docking analysis. The results generated in this study proved that resveratrol is a potent biofilm inhibitor of V. cholerae and can be used as a novel therapeutic agent against cholera. To our knowledge, this is the first report of resveratrol showing antibiofilm activity against V. cholerae. 相似文献
2.
Vibrio cholerae is the causative agent of water-borne diarrheal disease, cholera. The formation of biofilm favors survival and persistence
of V. cholerae in the aquatic environment and also inside the host. AHL lactonase (AiiA), a metallo-beta-lactamase produced by Bacillus spp., blocks quorum sensing in Gram-negative bacteria by hydrolyzing N-acyl-homoserine lactones (AHLs). In the present investigation,
AiiA-mediated inhibition of V. cholerae biofilm was studied. Two novel alleles of aiiA-encoding genes from Bacillus spp. were expressed in E. coli, and the results demonstrated that AiiA enzyme is a potent inhibitor of V. cholerae biofilm. 相似文献
3.
M. Anibou A. Chait A. Zyad M. Taourirt Y. Ouhdouch A. Benherref 《World journal of microbiology & biotechnology》2008,24(10):2019-2025
In our screening for actinomycetes showing cytotoxic activities, 8 samples were collected from various Moroccan habitats,
136 isolates were tested for their capacity to produce antibacterial compounds against gram positive bacteria. Thirty-seven
strains of these isolates were active against Gram-positive bacteria. Using the following steps of primary screening: antibacterial
activity, confrontation between the isolates and toxicity to Artemia salina; fifteen different isolates were used for further investigation. The aqueous extracts of Streptomyces sp. T5 and Streptomyces sp. AS8 were selected for their cytotoxic activity against Hep2, BSR and P815 cell lines, and two active compounds were observed
on HPLC. The two isolates exhibited high activity against human cancer cell lines and were inactive on PBMC cell lines. Furthermore,
the Streptomyces sp. T5 extract showed a proliferative activity. 相似文献
4.
Certain species of Vibrio cholerae have evolved mechanisms to become pathogenic to humans, with the potential to cause a severe life-threatening diarrheal disease,
cholera. Cholera can emerge as explosive outbreaks in the human population. V. cholerae illness is produced primarily through the expression of a potent toxin (cholera toxin) within the human intestine. The present
study has been carried out on a novel toxin purified from V. cholerae W07, an epidemic cholera strain devoid of cholera toxin gene (ctx). A modified method of purification improved purification fold as well as yield of this toxin. Heating was found to be the
essential and sufficient condition for dissociation of the two subunits (58 kDa and 40 kDa) of this toxin (pI 5.2). The 40-kDa
subunit of the purified toxin was identified as the carbohydrate binding subunit. This toxin was found to induce apoptosis
in HEp-2 cells. Thus, the WO7 toxin seems to have potential importance in the pathogenesis of disease associated with Vibrio cholerae WO7. 相似文献
5.
Endophytic actinomycetes from Azadirachta indica A. Juss. were screened and evaluated for their anti-microbial activity against an array of pathogenic fungi and bacteria.
A total of 55 separate isolates were obtained from 20 plants, and 60% of these showed inhibitory activity against one or more
pathogenic fungi and bacteria. Actinomycetes were most commonly recovered from roots (54.5% of all isolates), followed by
stems (23.6%), and leaves (21.8%). The dominant genus was Streptomyces (49.09% of all isolates), while Streptosporangium (14.5%), Microbispora (10.9%), Streptoverticillium (5.5%), Sacchromonospora sp. (5.5%), and Nocardia (3.6%) were also recovered. Streptomyces isolates AzR 006, 011, and 031 (all from roots) had acute activity against Pseudomonas fluorescens, while AzR027, 032, and 051 (also all from roots) showed activity against Escherichia coli. Meanwhile, an isolate of Nocardia sp. from leaves (AzL025) showed antagonism against Bacillus subtilis. Overall, 32 of the 55 were found to have broad spectrum significant antimicrobial activity, while about 4% of them showed
strong and acute inhibition to pathogenic fungi and bacteria. Isolates of Streptomyces AzR031, 008, and 047, Nocardia sp. AzL025, and Streptosporangium sp. AzR 021 and 048 are of particular interest because they showed significant antagonistic activity against root pathogens,
including Pythium and Phytophthora sp. Thus, many of the isolates recovered from A. indica in this study may be used in developing potential bio-control agents against a range of pathogenic fungi and bacteria and
in the production of novel natural antimicrobial compounds. These results not only further our understanding of plant–microbe
interactions but also indicate that there is an untapped resource of endophytic microorganisms that could be exploited in
the biotechnological, medicinal, and agricultural industries. 相似文献
6.
Promnuan Yaowanoot Kudo Takuji Chantawannakul Panuwan 《World journal of microbiology & biotechnology》2009,25(9):1685-1689
Actinomycetes are one of the main microbial groups that produce bioactive compounds used as antibiotics. Although bacteria,
mold and yeast have frequently been found in bees, the presence of actinomycetes in bee hives had not been previously identified
or reported. The aim of our research was to focus on the diversity of actinomycetes in bee hives in Thailand. Bees, brood
cells and hive materials were collected from apiaries and natural sources. Thirty-two isolates of actinomycetes were isolated
and identified using morphological, physiological, chemical and molecular characterization. Most of the isolates belonged
to the genus Streptomyces. Some less frequent isolates were classified in the genera Nonomuraea, Nocardiopsis and Actinomadura. 相似文献
7.
Isolation of endophytic actinomycetes from selected plants and their antifungal activity 总被引:9,自引:0,他引:9
Taechowisan Thongchai Peberdy John F. Lumyong Saisamorn 《World journal of microbiology & biotechnology》2003,19(4):381-385
The isolation of endophytic actinomycetes from surface-sterilized tissues of 36 plant species was made using humic acid–vitamin (HV) agar as a selection medium. Of the 330 isolates recovered, 212 were from roots, 97 from leaves and 21 isolates from stems with a prevalence of 3.9, 1.7 and 0.3%, respectively. Identification of endophytic actinomycetes was based on their morphology and the amino acid composition of the whole-cell extract. Most isolates were classified as Streptomyces sp. (n = 277); with the remainder belonging to Microbispora sp. (n = 14), Nocardia sp. (n = 8) and Micromonospora sp. (n = 4). Four isolates were unclassified and 23 were lost during subculture. The most prevalent group of isolates were the Streptomyces sp. occurring in 6.4% of the tissue samples of Zingiber officinale. Scanning electron microscopy investigation of this plant revealed that 7.5% of the root and 5% of the leaf samples contained endophytes. Three of the Streptomyces sp. isolates strongly inhibited Colletotrichum musae, five were very active against Fusarium oxysporum and two strongly inhibited growth of both test fungi. 相似文献
8.
J. J. Kingston K. Thavachelvam U. Tuteja T. James B. Janardhanan H. V. Batra 《Indian journal of microbiology》2009,49(1):84-88
The genotype and antibiotic resistance pattern of the toxigenic Vibrio cholerae strains associated with cholera outbreaks vary frequently. Fifty-one V. cholerae strains isolated from cholera outbreaks in Chennai (2002–2005) were screened for the presence of virulence and regulatory
genes by multiplex polymerase chain reaction (PCR) assay. Genotyping of the isolates was done by VC1 primers derived from
enterobacterial repetitive intergenic consensus (ERIC)-related sequence in V. cholerae. All the isolates possessed toxigenic genes, such as ctxA, ctxB, tcpA, ace, ompU, toxR and zot. Two different El Tor genotypes and one O139 genotype could be delineated by VC1-PCR. One of the El Tor genotypes was similar
to the El Tor strains isolated from Bhind district and Delhi during 2004. Antibiotic susceptibility testing revealed greater
variability among the isolates tested. All the isolates were found to be susceptible to norfloxacin, ciprofloxacin and tetracycline.
Thiry-three per cent of the isolates were found to be resistant to more than 4 antibiotics and could be termed as multiple
antibiotic resistant. Coexistence of O139 serogroup along with the El Tor biotype could be identified among the strains recovered
during the period 2002–2004. The O139 isolates were found to be more susceptible to the antibiotics tested when compared to
the El Tor isolates. 相似文献
9.
The occurrence of Aeromonas spp., Vibrio cholerae, and Plesiomonas shigelloides in fresh water from various sources in Araraquara, State of S?o Paulo, Brazil was determined. Samples from ten distinct irrigation
systems used in vegetable cultivation, from five distinct streams, from two reservoirs, from one artificial lake, and from
three distinct springs were analyzed. All isolates were serotyped and tested for hemolysin, cytotoxin, heat-stable (ST) and
heat-labile (LT) enterotoxins production; presence of plasmid; autoagglutination and drug resistance. V. cholerae isolates were also tested for cholera enterotoxin (CT) production, and Aeromonas isolates for suicide phenomenon. No P. shigelloides was found. V. cholerae non 01 was found in five irrigation water samples and in three stream samples. Aeromonas sp. were isolated in two samples of irrigation water, in three streams, and in one reservoir. All the V. cholerae and Aeromonas isolates were positive for β-hemolysin production, and all Aeromonas isolates were positive for suicide phenomenon; cytotoxic activities were observed in two Aeromonas strains. Cholera enterotoxin was not found in eight V. cholerae non-01 isolates tested by the Y-1 mouse adrenal cell. All isolates were also negative for the other virulence markers. V. cholerae isolates were found to be sensitive to the majority of drugs tested, while Aeromonas strains presented multiple drug resistance.
Received: 4 November 1997 / Accepted: 23 January 1998 相似文献
10.
Toxigenic Vibrio cholerae in the Aquatic Environment of Mathbaria, Bangladesh 总被引:2,自引:0,他引:2
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Munirul Alam Marzia Sultana G. Balakrish Nair R. Bradley Sack David A. Sack A. K. Siddique Afsar Ali Anwar Huq Rita R. Colwell 《Applied microbiology》2006,72(4):2849-2855
Toxigenic Vibrio cholerae, rarely isolated from the aquatic environment between cholera epidemics, can be detected in what is now understood to be a dormant stage, i.e., viable but nonculturable when standard bacteriological methods are used. In the research reported here, biofilms have proved to be a source of culturable V. cholerae, even in nonepidemic periods. Biweekly environmental surveillance for V. cholerae was carried out in Mathbaria, an area of cholera endemicity adjacent to the Bay of Bengal, with the focus on V. cholerae O1 and O139 Bengal. A total of 297 samples of water, phytoplankton, and zooplankton were collected between March and December 2004, yielding eight V. cholerae O1 and four O139 Bengal isolates. A combination of culture methods, multiplex-PCR, and direct fluorescent antibody (DFA) counting revealed the Mathbaria aquatic environment to be a reservoir for V. cholerae O1 and O139 Bengal. DFA results showed significant clumping of the bacteria during the interepidemic period for cholera, and the fluorescent micrographs revealed large numbers of V. cholerae O1 in thin films of exopolysaccharides (biofilm). A similar clumping of V. cholerae O1 was also observed in samples collected from Matlab, Bangladesh, where cholera also is endemic. Thus, the results of the study provided in situ evidence for V. cholerae O1 and O139 in the aquatic environment, predominantly as viable but nonculturable cells and culturable cells in biofilm consortia. The biofilm community is concluded to be an additional reservoir of cholera bacteria in the aquatic environment between seasonal epidemics of cholera in Bangladesh. 相似文献
11.
Vibrios in the Louisiana gulf coast environment 总被引:3,自引:0,他引:3
A polyphasic approach, using bacteriological, immunological, and molecular biological techniques was used to elucidate the distribution of pathogenicVibrio species in the Louisiana coastal environment. A variety ofVibrio species pathogenic for man, includingV. cholerae, V. parahaemolyticus, V. fluvialis, andV. vulnificus, were found to be ubiquitous in Louisiana.Vibrio species monitored were shown to fluctuate in response to environmental factors of temperature, salinity, and nutrient level, and to vary independently of fecal coliform counts. A comprehensive serological screening system, based on species specific H antigens, was developed to identify pathogenicVibrio sp. 1 step after primary isolation.Vibrio sp. were correctly identified with accuracies ranging from 93–100%, depending on the specific H antiserum. Over 2,500V. cholerae isolates were rapidly screened for production of cholera toxin by DNA hybridization of specific toxin gene probes to colonies inoculated on nitrocellulose filter paper. The toxin gene probes, together with O antigen analysis, revealed that enterotoxigenicV. cholerae 01 serovars were recovered only from sewage stations or human disease, whereas enterotoxigenicV. cholerae non 01 serovars were recovered from environmental samples in addition to clinical and sewage samples. The results of this study indicate that techniques of immunology and molecular biology are very valuable supplements to conventional bacteriological techniques in studying the epidemiology and ecology of pathogenicVibrio sp. 相似文献
12.
Sutthinan Khamna Akira Yokota Saisamorn Lumyong 《World journal of microbiology & biotechnology》2009,25(4):649-655
A total of 445 actinomycete isolates were obtained from 16 medicinal plant rhizosphere soils. Morphological and chemotaxonomic
studies indicated that 89% of the isolates belonged to the genus Streptomyces, 11% were non-Streptomycetes: Actinomadura sp., Microbispora sp., Micromonospora sp., Nocardia sp, Nonomurea sp. and three isolates were unclassified. The highest number and diversity of actinomycetes were isolated from Curcuma mangga rhizosphere soil. Twenty-three Streptomyces isolates showed activity against at least one of the five phytopathogenic fungi: Alternaria brassicicola, Collectotrichum gloeosporioides, Fusarium oxysporum, Penicillium digitatum and Sclerotium
rolfsii. Thirty-six actinomycete isolates showed abilities to produce indole-3-acetic acid (IAA) and 75 isolates produced siderophores
on chrome azurol S (CAS) agar. Streptomyces CMU-PA101 and Streptomyces CMU-SK126 had high ability to produced antifungal compounds, IAA and siderophores. 相似文献
13.
To verify the hypothesis on the involvement of commensal actinomycetes in the biosynthesis of plant maytansinoids that belong
to the ansamycin family, selective isolation and targeted screenings were conducted. In total, 164 endophytic actinomycetes
isolates were obtained from the roots, twigs, seeds, callus, and germ-free seedlings of “maytansinoids-producing” Trewia nudiflora Linn. by selective isolation methods. Crude extracts of the isolates were screened by antifungal bioassay against Penicillium avellaneum UC-4376, thin-layer chromatography, and liquid chromatography–mass spectrometry detection according to the bioactivity as
well as structural characteristics of maytansinoids. Respectively, 25.0%, 64.8%, and 26.7% of the extracts were positive in
corresponding screenings. Ten isolates showed positive results in all three different screenings. To confirm on a genetic
level, 28 representative isolates from 20 morphological groups were screened by polymerase chain reaction with 3-amino-5-hydroxybenzoic
acid synthase gene and carbamoyltransferase gene primers, both of which were involved in the biosynthesis of ansamycins. According
to the results of the targeted screenings, two isolates Streptomyces sp. 5B and Streptomyces sp. M27m3 might have the potential of producing ansamycins, which further enhanced the hypothesis that endophyte(s) might
be involved in the biosynthesis of plant maytansinoids. 相似文献
14.
Tadayori Shimizu Yasutake Yanagihara Yasunori Isshiki Yasuhisa Kawamata Seiichi Kondo Kazuhito Hisatsune 《Microbiology and immunology》1994,38(6):471-474
Biological activities of lipopolysaccharide (LPS) isolated from Vibrio cholerae O139, a new causative agent for recent cholera epidemic in Indian subcontinent, were investigated in comparison with those of LPS from O1 V. cholerae. V. cholerae O139 LPS exerted mitogenic activity, lethal toxicity and Shwartzman reaction to the same extent as those observed for O1 V. cholerae LPS, although these activities except for lethal toxicity were obviously lower than those of Salmonella typhimurium LT-2 LPS used as a reference. It was, therefore, suggested that O139 LPS does not contribute to the high infective and pathogenic potentials of the V. cholerae O139 strain as in the case of O1 V. cholerae. 相似文献
15.
Vibrio cholerae, the etiologic agent of cholera, is autochthonous to various aquatic environments. Recently, it was found that chironomid
(nonbiting midges) egg masses serve as a reservoir for the cholera bacterium and that flying chironomid adults are possible
windborne carriers of V. cholerae non-O1 non-O139. Chironomids are the most widely distributed insect in freshwater. Females deposit egg masses at the water's
edge, and each egg mass contains eggs embedded in a gelatinous matrix. Hemagglutinin/protease, an extracellular enzyme of
V. cholerae, was found to degrade chironomid egg masses and to prevent them from hatching. In a yearly survey, chironomid populations
and the V. cholerae in their egg masses followed phenological succession and interaction of host–pathogen population dynamics. In this report,
it is shown via FISH technique that most of the V. cholerae inhabiting the egg mass are in the viable but nonculturable (VBNC) state. The diversity of culturable bacteria from chironomid
egg masses collected from two freshwater habitats was determined. In addition to V. cholerae, representatives of the following genera were isolated: Acinetobacter, Aeromonas, Klebsiella, Shewanella, Pseudomonas, Paracoccus, Exiguobacterium, and unidentified bacteria. Three important human pathogens, Aeromonas
veronii, A. caviae, and A. hydrophila, were isolated from chironomid egg masses, indicating that chironomid egg masses may be a natural reservoir for pathogenic
Aeromonas species in addition to V. cholerae. All isolates of V. cholerae were capable of degrading chironomid egg masses. This may help explain their host–pathogen relationship with chironomids.
In contrast, almost none of the other bacteria that were isolated from the egg masses possessed this ability. Studying the
interaction between chironomid egg masses, the bacteria inhabiting them, and V. cholerae could contribute to our understanding of the nature of the V. cholerae–egg mass interactions. 相似文献
16.
Goel AK Jain M Kumar P Sarguna P Bai M Ghosh N Gopalan N 《Journal of microbiology (Seoul, Korea)》2011,49(2):280-284
Thirty-four Vibrio cholerae isolates collected from a cholera outbreak in Hyderabad, South India were found to belong to serogroup Ol biotype El Tor
serotype Ogawa. The genotype of all the isolates was confirmed by PCR assays. All the isolates were found PCR positive for
ctxAB, ompW, rflOl, rtxC, and tcpA genes. All the isolates but one harboured rstR
El Tor
allele. However, one isolate carried both rstR
EL Tor
as well as rstR
Classical
alleles. Cholera toxin (ctxB) genotyping of the isolates confirmed the presence of altered cholera toxin B of classical biotype in all the isolates. All
the isolates except VCH35 harboured an RS1-CTX prophage array on the large chromosome. The isolate VCH35 contained a tandem
repeat of classical CTX prophage on the small chromosome. The clonal relationship among the V. cholerae isolates as carried out by enterobacterial repetitive intergenic consensus sequences PCR, BOX PCR and randomly amplified
polymorphic DNA, uniformly showed a genetic relationship among the outbreak isolates. The results of this study suggest that
altered El Tor biotype V. cholerae with the classical cholera toxin gene are involved in cholera outbreaks in India. 相似文献
17.
Vibrio cholerae produces cholera toxin (CT) that consists of two subunits, A and B, and is encoded by a filamentous phage CTXΦ. The A subunit
carries enzymatic activity that ribosylates ADP, whereas the B subunit binds to monosialoganglioside (GM1) receptor in epithelial
cells. Molecular analysis of toxigenic V. cholerae strains indicated the presence of multiple ctxB genotypes. In this study, we employed a comparative modeling approach to
define the structural features of all known variants of ctxB found in O139 serogroup V. cholerae. Modeling, molecular dynamics and docking simulations studies suggested subtle variations in the binding ability of ctxB
variants to carbohydrate ligands of GM1 (galactose, sialic acid and N-acetyl galactosamine). These findings throw light on the molecular efficiencies of pathogenic isolates of V. cholerae harboring natural variants of ctxB in causing the disease, thus suggesting the need to consider ctxB variations when designing vaccines against cholera. 相似文献
18.
All the V. cholerae non-O1, non-O139 isolates from ground and surface water samples collected during the rainy season (rainfall contributes significantly
in the spread of cholera) contained ompW and a regulatory toxR gene, while many others possessed accessory cholera toxin (ace), hemolysin (hlyA) and outer membrane protein (ompU) genes. All the isolates lacked ctxAB, tcp, zot, rfbO1 and rfbO139 genes. The strains could be grouped into two main clusters colligating the isolates from ground water and surface water samples.
The results suggest that surface water harbors various virulent V. cholerae strains that contaminate the ground water due to rain or poor hygienic practices, and result in the emergence of new toxigenic
strains for cholera. 相似文献
19.
Joseph J. Kingston Kuruvilla Zachariah Urmil Tuteja Sanjay Kumar Harsh Vardhan Batra 《Journal of microbiology (Seoul, Korea)》2009,47(1):110-115
Vibrio cholerae isolates recovered from cholera outbreaks in Bhind district of Madhya Pradesh and Delhi, Northern India were characterized.
The O1 serogroup isolates from Bhind outbreak were of Inaba serotype whereas both Ogawa and Inaba serotypes were recovered
from Delhi. PCR analysis revealed that only O1 serogroup V. cholerae isolates carried the virulence-associated genes like ctxA, tcpA, ace, and zot. Molecular typing by repetitive sequence based ERIC, VCR1, and VC1 PCR’s revealed similar DNA profile for both Inaba and
Ogawa serotypes. A discrete VC1-PCR band identified among the El Tor strains had greater similarity (>97%) to the V. cholerae genome sequence and therefore has the potential to be used as a marker for the identification of the V. cholerae strains. Non-O1 strains recovered from Bhind region differed among themselves as well as from that of the O1 isolates. All
the O1 serogroup isolates possessed SXT element and were uniformly resistant to the antibiotics nalidixic acid, polymyxin-B,
furazolidone, cloxacilin, trimethoprim-sulfamethaxazole, and vibriostatic agent 0129. Inaba strains from both Delhi and Bhind
differed from Ogawa strains by their resistance to streptomycin despite sharing similar DNA patterns in all the three rep-PCRs.
Though Delhi and Bhind are separate geographical regions in Northern India, Inaba strains from both these places appear to
be closely related owing to their similarity in antibiogram and genetic profile. 相似文献
20.
Kirschner AK Schauer S Steinberger B Wilhartitz I Grim CJ Huq A Colwell RR Herzig A Sommer R 《Microbial ecology》2011,61(3):496-506
Vibrio cholerae is a human pathogen and natural inhabitant of aquatic environments. Serogroups O1/O139 have been associated with epidemic cholera, while non-O1/non-O139 serogroups usually cause human disease
other than classical cholera. V. cholerae non-O1/non-O139 from the Neusiedler See, a large Central European lake, have caused ear and wound infections, including one
case of fatal septicaemia. Recent investigations demonstrated rapid planktonic growth of V. cholerae non-O1/non-O139 and correlation with zooplankton biomass. The aim of this study was to elucidate the interaction of autochthonous
V. cholerae with two dominant crustacean zooplankton species in the lake and investigate the influence of the natural bacterial community
on this interaction. An existing data set was evaluated for statistical relationships between zooplankton species and V. cholerae and co-culture experiments were performed in the laboratory. A new fluorescence in situ hybridisation protocol was applied
for quantification of V. cholerae non-O1/non-O139 cells, which significantly reduced analysis time. The experiments clearly demonstrated a significant relationship
of autochthonous V. cholerae non-O1/non-O139 with cladocerans by promoting growth of V. cholerae non-O1/non-O139 in the water and on the surfaces of the cladocerans. In contrast, copepods had a negative effect on the growth
of V. cholerae non-O1/non-O139 via competing bacteria from their surfaces. Thus, beside other known factors, biofilm formation by V. cholerae on crustacean zooplankton appears to be zooplankton taxon specific and may be controlled by the natural bacterial community. 相似文献