Displaying publications 21 - 40 of 44 in total

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  1. Fulltext Vibrio parahaemolyticus: a review on the pathogenesis, prevalence, and advance molecular identification techniques
    Letchumanan V, Chan KG, Lee LH
    Front Microbiol, 2014;5:705.
    PMID: 25566219 DOI: 10.3389/fmicb.2014.00705
    Vibrio parahaemolyticus is a Gram-negative halophilic bacterium that is found in estuarine, marine and coastal environments. V. parahaemolyticus is the leading causal agent of human acute gastroenteritis following the consumption of raw, undercooked, or mishandled marine products. In rare cases, V. parahaemolyticus causes wound infection, ear infection or septicaemia in individuals with pre-existing medical conditions. V. parahaemolyticus has two hemolysins virulence factors that are thermostable direct hemolysin (tdh)-a pore-forming protein that contributes to the invasiveness of the bacterium in humans, and TDH-related hemolysin (trh), which plays a similar role as tdh in the disease pathogenesis. In addition, the bacterium is also encodes for adhesions and type III secretion systems (T3SS1 and T3SS2) to ensure its survival in the environment. This review aims at discussing the V. parahaemolyticus growth and characteristics, pathogenesis, prevalence and advances in molecular identification techniques.
    Matched MeSH terms: Hemolysin Proteins
  2. The role of genomic islands in Escherichia coli K1 interactions with intestinal and kidney epithelial cells
    Yousuf FA, Rafiq S, Siddiqui R, Khan NA
    Microb Pathog, 2016 Apr;93:145-51.
    PMID: 26867478 DOI: 10.1016/j.micpath.2016.02.002
    The completion of Escherichia coli K1 genome has identified several genomic islands that are present in meningitis-causing E. coli RS218 but absent in the non-pathogenic E. coli MG1655. In this study, the role of various genomic islands in E. coli K1 interactions with intestinal epithelial cells (Caco-2) and kidney epithelial cells (MA104) was determined. Using association assays, invasion assays, and intracellular survival assays, the findings revealed that the genomic island deletion mutants of RS218 related to P fimbriae, S fimbriae, F17-like fimbriae, non-fimbrial adhesins, Hek and hemagglutinin, protein secretion system (T1SS for hemolysin; T2SS; T5SS for antigen 43), Iro system and hmu system), invasins (CNF1, IbeA), toxins (α-hemolysin), K1 capsule biosynthesis, metabolism (d-serine catabolism, dihydroxyacetone, glycerol, and glyoxylate metabolism), prophage genes, showed reduced interactions with both cell types. Next, we determined the role of various genomic islands in E. coli K1 resistance to serum. When exposed to the normal human serum, the viability of the genomic island deletion mutants related to adhesins such as S fimbriae, P fimbriae, F17-like fimbriae, non-fimbrial adhesins, Hek and hemagglutinin, antigen 43 and T5SS for antigen 43, T2SS, and T1SS for hemolysin, Iro system and hmu system, prophage genes, metabolism (sugar metabolism and d-serine catabolism), K1 capsule biosynthesis, and invasins such as CNF1 was affected, suggesting their role in bacteremia. The characterization of these genomic islands should reveal mechanisms of E. coli K1 pathogenicity that could be of value as therapeutic targets.
    Matched MeSH terms: Hemolysin Proteins
  3. Fulltext Survival study and haemolysin activity of Escherichia coli in raw and pasteurized milk produced in Negeri Sembilan
    Farra Amira Mohamed, Aimi Nadia Ramli,, Noorlis Ahmad
    Journal of Academia Universiti Teknologi MARA Negeri Sembilan, 2020;8(1):66-77.
    MyJurnal
    Demand for milk has increased in Malaysia due to the increased in awareness of healthy foods consumption.
    Hence, research of milk is crucial to ensure that it is not contaminated with Escherichia coli. This study
    evaluated the survival of Escherichia coli at different temperature and haemolysin activity of Escherichia
    coli on blood agar. A total of 8 samples of raw fresh and pasteurized milk were collected from nearby farm
    and market in Negeri Sembilan, Malaysia. After an overnight exposure to four different temperatures of
    0
    0C, 280C, 350C and 450C, the bacteriological test of milk was evaluated for the presence of Escherichia
    coli. Overall, all raw fresh milk sampled exceeded the acceptable limit of bacterial count of 1 x 105 CFU/ml.
    Raw fresh milk recorded the highest count at 35oC with 4.4 x 107 CFU/ml and the lowest at 0oC with 8.3 x
    104 CFU/ml. The presence of Escherichia coli was detected in 7/20(35%) of the total raw fresh milk
    samples. All pasteurized milk showed no presence of Escherichia coli due to the effectiveness of heat
    treatment. Haemolysin test showed no haemolytic activity. Milk contaminated with Escherichia coli can
    cause diarrheal, gastrointestinal diseases and urinary infection. Hence, it is important to study the survival
    rate of Escherichia coli and its pathogenicity in milk to ensure public safety.
    Matched MeSH terms: Hemolysin Proteins
  4. Fulltext Molecular characterisation of Vibrio parahaemolyticus carrying tdh and trh genes using ERIC-, RAPD- and BOX-PCR on local Malaysia bloody clam and Lala
    Yoke-Kqueen, C., Teck-Ee, K., Son, R, Yoshitsugu, N., Mitsuaki, N.
    International Food Research Journal, 2013;20(6):3299-3305.
    MyJurnal
    Molecular typing methods have been widely applied for many purposes. In this study, such methods were adopted as DNA fingerprinting tools to determine the origin and divergence of virulent Vibrio parahaemolyticus strains found in local seafood. Although not all strain carry virulent tdh and trh gene, increasing prevalence demands an effective fingerprinting scheme which can constantly monitor and trace the sources of such emerging food pathogens. By using ERIC-, RAPD-, and BOX-PCR methods, 33 Vibrio parahaemolyticus isolates from local Malaysia bloody clam (Anadara granosa) and Lala (Orbicularia orbiculata) with confirmed presence of tdh and trh gene were characterised, followed by determination of clonal relatedness among virulent strains using cluster analysis and discriminatory index. This study also involved application of Immunomagnetic Separation (IMS) Method which significantly improved the specificity of strain isolation. Cluster analysis using Unweighted Pair Group Mathematical Averaging (UPGMA) and Dice Coefficient shown clustering according to isolation food source, IMS level and haemolysin gene possessed. Nevertheless, different DNA fingerprinting methods generated different clustering at different similarity cut-off percentage, regardless as individual or as composite dendrograms. ERIC- and RAPD-PCR composite fingerprinting relatively shown the highest discriminatory index at following similarity cutoff percentage: 0.68 at 50%; 0.83 at 65%; and 0.93 at 75%. Discriminatory power increased with similarity cut-off percentage. However, result also suggested that BOX-PCR might be an effective fingerprinting tool, as it generated three clusters with no single-colony isolate at 70% similarity cut-off. This study not only achieved its objective to determine clonal relatedness among virulent strains from local seafood via characterisation, but also speculated the best possible combination of molecular typing methods to effectively do so.
    Matched MeSH terms: Hemolysin Proteins
  5. Fulltext Detection of aerolysin and hemolysin genes in Aeromonas spp. isolated from environmental and shellfish sources by polymerase chain reaction
    Yousr, A.H., Nipis, S., Rusul, G.R.A., Son, R.
    International Food Research Journal, 2007;14(2):115-122.
    MyJurnal
    Polymerase chain reaction (PCR) technique was used to assay for the detection of specific genes in the genomes of the Aeromonas spp. isolated from environmental and shellfish sources, particularly aero and hlyA genes, responsible for aerolysin and hemolysin toxins production in this genus. The results showed that: (i) the 1500 bp amplicon of the hlyA gene was detected in 20/38 of the Aeromonas hydrophila, 13/38 of the A. caviae and 6/9 of the A. veronii biovar sobria isolates; (ii) the 690 bp amplicon of the aero gene was detected in 20/38 of A. hydrophila, 17/38 of A. caviae and 6/9 of A. veronii biovar sobria isolates; (iii) the nucleotide blast results of aerolysin gene sequences of the representative strains of A. hydrophila, A. caviae and A. veronii biovar sobria revealed a high homology of 94%, 95% and 95% with published sequences, respectively and ; (iv) the protein blast showed 97%, 94% and 96% homology when compared to the published sequences, respectively. The finding of A. hydrophila virulence genes in other members of the genus Aeromonas, may give a new perspective to the significance of these results. The method described here may be a useful detection tool to assist in further investigation of aero and hlyA genes in the genus Aeromonas, especially for food microbiologist.
    Matched MeSH terms: Hemolysin Proteins
  6. Fulltext Genome-based proteomic analysis of Lignosus rhinocerotis (Cooke) Ryvarden sclerotium
    Yap HY, Fung SY, Ng ST, Tan CS, Tan NH
    Int J Med Sci, 2015;12(1):23-31.
    PMID: 25552915 DOI: 10.7150/ijms.10019
    Lignosus rhinocerotis (Cooke) Ryvarden (Polyporales, Basidiomycota), also known as the tiger milk mushroom, has received much interest in recent years owing to its wide-range ethnobotanical uses and the recent success in its domestication. The sclerotium is the part with medicinal value. Using two-dimensional gel electrophoresis coupled with mass spectrometry analysis, a total of 16 non-redundant, major proteins were identified with high confidence level in L. rhinocerotis sclerotium based on its genome as custom mapping database. Some of these proteins, such as the putative lectins, immunomodulatory proteins, superoxide dismutase, and aegerolysin may have pharmaceutical potential; while others are involved in nutrient mobilization and the protective antioxidant mechanism in the sclerotium. The findings from this study provide a molecular basis for future research on potential pharmacologically active proteins of L. rhinocerotis.
    Matched MeSH terms: Hemolysin Proteins/pharmacology
  7. Fulltext Antihaemolytic and snake venom neutralizing effect of some Indian medicinal plants
    Kumarapppan C, Jaswanth A, Kumarasunderi K
    Asian Pac J Trop Med, 2011 Sep;4(9):743-7.
    PMID: 21967700 DOI: 10.1016/S1995-7645(11)60185-5
    OBJECTIVE: To validate traditional claims of usefulness of the Indian plants in management of poisonous snakebite and evaluate the antivenom properties displayed by the alcoholic extracts of Andrographis paniculata (A. paniculata), Crateva magna (C. magna), Gloriosa superba (G. superba) and Hydrocotyle javanica (H. javanica).

    METHODS: These plants were collected, identified and the extracts were prepared by using conventional Soxhlet ethanol extraction technique. The venom neutralization activity was accessed in mice (20-25g) and number of mortalities was observed against clinically important snake (Naja nigricollis) venom. Present study also deals with in vitro membrane stabilizing activity of these plants against hyposaline induced human red blood corpuscles (HRBC).

    RESULTS: Extracts of H. javanica and G. superba gave 80 % and 90 % protection to mice treated with minimum lethal dose of venom (LD(99)). These two plants showed significant neutralization effect against the venoms of Naja nigricollis venom. H. javanica and G. superba (25-100 mg/mL) produced significant changes of membrane stabilization of human red blood cells (HRBC) exposed to hyposaline-induced haemolysis.

    CONCLUSIONS: We conclude that probably due to presence of various phytochemicals plays an important role in the anti-venom potential of these Indian medicinal plants against Naja nigricollis venom. The above observations confirmed that A. paniculata, C. magna, G. superba and H. javanica plant extracts possess potent snake venom neutralizing capacity and could potentially be used as an adjuvants for antivenin therapy in case of snakebite envenomation, especially against the local effects of cobra venoms.

    Matched MeSH terms: Hemolysin Proteins/antagonists & inhibitors*
  8. Enhanced secretory production of hemolysin-mediated cyclodextrin glucanotransferase in Escherichia coli by random mutagenesis of the ABC transporter system
    Low KO, Mahadi NM, Abdul Rahim R, Rabu A, Abu Bakar FD, Abdul Murad AM, et al.
    J Biotechnol, 2010 Dec;150(4):453-9.
    PMID: 20959127 DOI: 10.1016/j.jbiotec.2010.10.001
    The hemolysin transport system was found to mediate the release of cyclodextrin glucanotransferase (CGTase) into the extracellular medium when it was fused to the C-terminal 61 amino acids of HlyA (HlyAs(61)). To produce an improved-secretion variant, the hly components (hlyAs, hlyB and hlyD) were engineered by directed evolution using error-prone PCR. Hly mutants were screened on solid LB-starch plate for halo zone larger than the parent strain. Through screening of about 1 × 10(4) Escherichia coli BL21(DE3) transformants, we succeeded in isolating five mutants that showed a 35-217% increase in the secretion level of CGTase-HlyAs(61) relative to the wild-type strain. The mutation sites of each mutant were located at HlyB, primarily along the transmembrane domain, implying that the corresponding region was important for the improved secretion of the target protein. In this study we describe the finding of novel site(s) of HlyB responsible for enhancing secretion of CGTase in E. coli.
    Matched MeSH terms: Hemolysin Proteins/metabolism*
  9. Cross-resistance between a Bacillus thuringiensis Cry toxin and non-Bt insecticides in the diamondback moth
    Sayyed AH, Moores G, Crickmore N, Wright DJ
    Pest Manag Sci, 2008 Aug;64(8):813-9.
    PMID: 18383197 DOI: 10.1002/ps.1570
    Bacillus thuringiensis Berliner (Bt) crystal (Cry) toxins are expressed in various transgenic crops and are also used as sprays in integrated pest management and organic agricultural systems. The diamondback moth (Plutella xylostella L.) is a major worldwide pest of crucifer crops and one that has readily acquired field resistance to a broad range of insecticides.
    Matched MeSH terms: Hemolysin Proteins/pharmacology*
  10. Fulltext Evaluation of PAIusp subtyping to characterize uropathogenic E. coli isolates
    Lai YM, Zaw MT, Shamsudin SB, Lin Z
    J Infect Dev Ctries, 2016 Oct 31;10(10):1053-1058.
    PMID: 27801366 DOI: 10.3855/jidc.6944
    INTRODUCTION: Uropathogenic virulence factors have been identified by comparing the prevalence of these among urinary tract isolates and environmental strains. The uropathogenic-specific protein (USP) gene is present on the pathogenicity island (PAI) of uropathogenic Escherichia coli (UPEC) and, depending on its two diverse gene types and the sequential patterns of three open reading frame units (orfUs) following it, there is a method to characterize UPEC epidemiologically called PAIusp subtyping.
    METHODOLOGY: A total of 162 UPEC isolates from Sabah, Malaysia, were tested for the presence of the usp gene and the sequential patterns of three orfUs following it using polymerase chain reaction (PCR). In addition, by means of triplex PCR, the prevalence of the usp gene was compared with other two VFs of UPEC, namely alpha hemolysin (α-hly) and cytotoxic necrotizing factor (cnf-1) genes encoding two toxins.
    RESULTS: The results showed that the usp gene was found in 78.40% of UPEC isolates, indicating that its prevalence was comparable to that found in a previous study in Japan. The two or three orfUs were also associated with the usp gene in this study. All the PAIusp subtypes observed in Japan were present in this study, while subtype IIa was the most common in both studies. The usp gene was observed in a higher percentage of isolates when compared with α-hly and cnf-1 genes.
    CONCLUSIONS: The findings in Japan and Sabah, East Malaysia, were similar, indicating that PAIusp subtyping is applicable to the characterization of UPEC strains epidemiologically elsewhere in the world.
    Matched MeSH terms: Hemolysin Proteins/genetics
  11. Fulltext Prevalence, virulence and antifungal activity of C. albicans isolated from infected root canals
    Abraham SB, Al Marzooq F, Himratul-Aznita WH, Ahmed HMA, Samaranayake LP
    BMC Oral Health, 2020 12 01;20(1):347.
    PMID: 33256696 DOI: 10.1186/s12903-020-01347-5
    BACKGROUND: There is limited data on the prevalence of Candida species in infected root canal systems of human teeth. We attempted to investigate the prevalence, genotype, virulence and the antifungal susceptibility of Candida albicans isolated from infected root canals of patients with primary and post-treatment infections in a UAE population.

    METHODS: Microbiological samples from 71 subjects with infected root canals were aseptically collected, and cultured on Sabouraud dextrose agar, and C. albicans was identified using multiplex polymerase chain reaction, and the isolates were further subtyped using ABC genotyping system. Their relative virulence was compared using further four archival samples of endodontic origin from another geographical region, and four more salivary isolates, as controls. The virulence attributes compared were biofilm formation, and production of phospholipase and haemolysin, and the susceptibility to nystatin, amphotericin B, ketoconazole, and fluoconazole was also tested.

    RESULTS: 4 out of 71 samples (5.6%) yielded Candida species. On analysis of variance among the groups, the intracanal isolates, mainly Genotype A, possessed a high degree of phospholipase and haemolysin activity (p 

    Matched MeSH terms: Hemolysin Proteins
  12. Cloning and expression of the first anaerobic toxin gene from Clostridium bifermentans subsp. malaysia, encoding a new mosquitocidal protein with homologies to Bacillus thuringiensis delta-endotoxins
    Barloy F, Delécluse A, Nicolas L, Lecadet MM
    J Bacteriol, 1996 Jun;178(11):3099-105.
    PMID: 8655486
    A gene (cbm71) encoding a 71,128-Da mosquitocidal protein (Cbm71) was obtained by screening a size-fractionated XbaI digest of total genomic DNA from Clostridium bifermentans subsp. malaysia CH18 with two gene-specific oligonucleotide probes. The sequence of the Cbm71 protein, as deduced from the sequence of cbm71, corresponds to that of the 66-kDa protein previously described as one of the mosquitocidal components of C. bifermentans subsp. malaysia. Cbm71 shows limited similarities with Bacillus thuringiensis delta-endotoxins, especially in the four first conserved blocks. However, Cbm71 was not immunologically related to any of the Cry toxins and thus belongs to a novel class of mosquitocidal protein. The cbm71 gene was expressed in a nontoxic strain of B. thuringiensis, and Cbm71 was produced during sporulation and secreted to the supernatant of culture. Trichloroacetic-precipitated supernatant preparations were toxic for mosquito larvae of the species Aedes aegypti, Culex pipiens, and Anopheles stephensi.
    Matched MeSH terms: Hemolysin Proteins
  13. Rapid detection and enumeration of pathogenic Vibrio parahaemolyticus in raw vegetables from retail outlets
    International Food Research Journal, 2011;18(1):67-78.
    MyJurnal
    This study aims to determine the frequency and density of potentially pathogenic Vibrio parahaemolyticus, defined as those possessing thermostable-direct hemolysin (tdh) and/or tdh-related hemolysin (trh) genes, in raw salad vegetables at retail level in Selangor, Malaysia. A combination of Most Probable Number - Polymerase Chain Reaction (MPN-PCR) method was applied to detect the presence of tdh and/or trh gene-possessing V. parahaemolyticus and to enumerate their density in the samples. A total of 276 samples of vegetables commonly eaten raw in Malaysia (Cabbage = 30; Carrot = 31; Cucumber = 28; Four winged bean = 26; Indian pennywort = 17; Japanese parsley = 21; Lettuce = 16; Long bean = 32; Sweet potato = 29; Tomato = 38; Wild cosmos = 8) were analyzed. The samples were purchased from two supermarkets (A and B) and two wet markets (C and D). With the MPN-PCR technique, about 12.0% of the samples were positive for the presence of V. parahaemolyticus tdh-positive, with maximum densities of up to 39 MPN/g. The total frequency of V. parahaemolyticus trh-positive in the samples was 10.1%, with maximum concentration 15 MPN/g. V. parahaemolyticus tdh-positive was most prevalent in samples from Wet Market C (20.78%) and also in vegetable type Oenanthe stolonifera (Japanese parsley) with 19.0%, while V. parahaemolyticus trhpositive was predominant in samples from Wet Market D (16.7%) and was most frequent in both Oenanthe stolonifera (Japanese parsley) and Cucumis sativus (Cucumber) with 14.3% prevalence for each type. The results highlighted the fact that raw vegetables could be contaminated with virulent V. parahaemolyticus and could act as a transmission route, thus poses risk to consumers from the consumption of raw vegetables. To the author’s knowledge, this is the first assessment of V. parahaemolyticus carrying tdh and trh genes in raw
    vegetables from retail outlets in Malaysia.
    Matched MeSH terms: Hemolysin Proteins
  14. Fulltext Detection and antibiotic susceptibility profiles of Listeria monocytogenes in wildlife and water samples in Kubah National Park, Sarawak, Malaysia
    Lesley, M.B., Velnetti, L., Fazira, A.A., Kasing, A., Samuel, L., Micky, V., et al.
    International Food Research Journal, 2016;23(1):360-365.
    MyJurnal
    This study was conducted to detect the presence of Listeria monocytogenes (L. monocytogenes)
    and screen for its antibiotic susceptibility characteristic from wildlife and water samples at
    Kubah National Park, Sarawak, Malaysia. Samples collected were incubated and streaked on
    selective medium PALCAM agar to confirm the presence of Listeria spp. before they were
    further tested using molecular analysis. Specific Polymerase Chain Reaction (PCR) assay were
    performed to target specific virulence gene, haemolysin gene, hlyA to further distinguish the
    presence of this pathogenic bacteria in the samples. Overall, out of the 30 samples tested, 10
    samples were confirmed as to contain L. monocytogenes strains and selected to subsequent
    antibiotic susceptibility test. Susceptibility patterns to 10 antibiotics were investigated
    among the L. monocytogenes strains. All strains were uniformly resistant to tetracycline and
    erythromycin. On the other hand, all strains were sensitive to gentamycin and tobramycin. The
    multiple antibiotic resistance shown by the strains in this study indicate the potential health
    hazard associated with the possible transmission between wildlife and water to its surrounding
    environment especially visitors and workers of Kubah National Park, Sarawak, Malaysia.
    Matched MeSH terms: Hemolysin Proteins
  15. Fipronil resistance in the diamondback moth (Lepidoptera: Plutellidae): inheritance and number of genes involved
    Sayyed AH, Wright DJ
    J Econ Entomol, 2004 Dec;97(6):2043-50.
    PMID: 15666763
    Bioassays (at generation 1, G1) using fipronil, spinosad, indoxacarb, and Bacillus thuringiensis toxins Cry1Ac and Cry1Ca with a newly collected field population of Plutella xylostella (L.) from farmers fields in the Cameron Highlands, Malaysia, indicated a resistance ratio of approximately 400-, 1,170-, 330-, 2,840-, and 1,410-fold, respectively, compared with a laboratory-susceptible population of P. xylostella (ROTH). At G3, the field-derived population was divided into two subpopulations, one was selected (G3 to G7) with fipronil (fip-SEL), whereas the second was left unselected (UNSEL). Bioassays at G8 found that selection with fipronil gave a resistance ratio of approximately 490 compared with UNSEL and approximately 770 compared with ROTH. The resistance ratio for fipronil, spinosad, indoxacarb, Cry1Ac, and Cry1Ca in the UNSEL population declined significantly by G8. Logit regression analysis of F1 reciprocal crosses between fip-SEL (at G8) and UNSEL indicated that resistance to fipronil in the fip-SEL population was inherited as an autosomal, incompletely recessive (D(LC) = 0.37) trait. At the highest dose of fipronil tested, resistance was completely recessive, whereas at the lowest dose it was incompletely recessive. A direct test of monogenic inheritance based on a backcross of F1 progeny with fip-SEL suggested that resistance to fipronil was controlled by a single locus. The fip-SEL population at G8 showed little change in its response to spinosad and indoxacarb compared with G1, whereas its susceptibility to Cry1Ac and Cry1Ca increased markedly over the selection period. This suggests that there may be some low level of cross-resistance between fipronil, spinosad, and indoxacarb.
    Matched MeSH terms: Hemolysin Proteins
  16. Fulltext Suppression of Staphylococcus aureus biofilm formation and virulence by a benzimidazole derivative, UM-C162
    Kong C, Chee CF, Richter K, Thomas N, Abd Rahman N, Nathan S
    Sci Rep, 2018 02 09;8(1):2758.
    PMID: 29426873 DOI: 10.1038/s41598-018-21141-2
    Staphylococcus aureus is a major cause of nosocomial infections and secretes a diverse spectrum of virulence determinants as well as forms biofilm. The emergence of antibiotic-resistant S. aureus highlights the need for alternative forms of therapeutics other than conventional antibiotics. One route to meet this need is screening small molecule derivatives for potential anti-infective activity. Using a previously optimized C. elegans - S. aureus small molecule screen, we identified a benzimidazole derivative, UM-C162, which rescued nematodes from a S. aureus infection. UM-C162 prevented the formation of biofilm in a dose-dependent manner without interfering with bacterial viability. To examine the effect of UM-C162 on the expression of S. aureus virulence genes, a genome-wide transcriptome analysis was performed on UM-C162-treated pathogen. Our data indicated that the genes associated with biofilm formation, particularly those involved in bacterial attachment, were suppressed in UM-C162-treated bacteria. Additionally, a set of genes encoding vital S. aureus virulence factors were also down-regulated in the presence of UM-C162. Further biochemical analysis validated that UM-C162-mediated disruption of S. aureus hemolysins, proteases and clumping factors production. Collectively, our findings propose that UM-C162 is a promising compound that can be further developed as an anti-virulence agent to control S. aureus infections.
    Matched MeSH terms: Hemolysin Proteins
  17. Isolation and Identification of novel toxins from a new mosquitocidal isolate from Malaysia, Bacillus thuringiensis subsp. jegathesan
    Kawalek MD, Benjamin S, Lee HL, Gill SS
    Appl Environ Microbiol, 1995 Aug;61(8):2965-9.
    PMID: 7487029
    A new mosquitocidal Bacillus thuringiensis subsp., jegathesan, has recently been isolated from Malaysia. Parasporal crystal inclusions were purified from this strain and bioassayed against fourth-instar larvae of Culex quinquefasciatus, Aedes aegypti, Aedes togoi, Aedes albopictus, Anopheles maculatus, and Mansonia uniformis. The 50% lethal concentration of crystal inclusions for each species was 0.34, 8.08, 0.34, 17.59, 3.91, and 120 ng/ml, respectively. These values show that parasporal inclusions from this new subspecies have mosquitocidal toxicity comparable to that of inclusions isolated from B. thuringiensis subsp. israelensis. Solubilized and chymotrypsin-activated parasporal inclusions possessed low-level hemolytic activity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the crystals were composed of polypeptides of 77, 74, 72, 68, 55, 38, 35, 27, and 23 kDa. Analysis by Western blotting (immunoblotting) with polyclonal antisera raised against toxins purified from B. thuringiensis subsp. israelensis reveals that proteins in parasporal inclusions of subsp. jegathesan are distinct, because little cross-reactivity was shown. Analysis of the plasmid content of B. thuringiensis subsp. jegathesan indicates that the genes for toxin production may be located on 105- to 120-kb plasmids. Cry- clones that have been cured of these plasmids are nontoxic. Southern blot analysis of plasmid and chromosomal DNA from subsp. jegathesan showed little or low homology to the genes coding for CryIVA, CryIVB, and CryIVD from B. thuringiensis subsp. israelensis.
    Matched MeSH terms: Hemolysin Proteins
  18. Application of streptavidin mass spectrometric immunoassay tips for immunoaffinity based antibody phage display panning
    Chin CF, Ler LW, Choong YS, Ong EB, Ismail A, Tye GJ, et al.
    J Microbiol Methods, 2016 Jan;120:6-14.
    PMID: 26581498 DOI: 10.1016/j.mimet.2015.11.007
    Antibody phage display panning involves the enrichment of antibodies against specific targets by affinity. In recent years, several new methods for panning have been introduced to accommodate the growing application of antibody phage display. The present work is concerned with the application of streptavidin mass spectrometry immunoassay (MSIA™) Disposable Automation Research Tips (D.A.R.T's®) for antibody phage display. The system was initially designed to isolate antigens by affinity selection for mass spectrometry analysis. The streptavidin MSIA™ D.A.R.T's® system allows for easy attachment of biotinylated target antigens on the solid surface for presentation to the phage library. As proof-of-concept, a domain antibody library was passed through the tips attached with the Hemolysin E antigen. After binding and washing, the bound phages were eluted via standard acid dissociation and the phages were rescued for subsequent panning rounds. Polyclonal enrichment was observed for three rounds of panning with five monoclonal domain antibodies identified. The proposed method allows for a convenient, rapid and semi-automated alternative to conventional antibody panning strategies.
    Matched MeSH terms: Hemolysin Proteins/chemistry
  19. Detection of Vibrio parahaemolyticus in cockle (Anadara granosa) by PCR
    Bilung LM, Radu S, Bahaman AR, Rahim RA, Napis S, Ling MW, et al.
    FEMS Microbiol Lett, 2005 Nov 1;252(1):85-8.
    PMID: 16216442
    This study aimed to determine the occurrence of Vibrio parahaemolyticus in cockles (Anadara granosa) at a harvesting area and to detect the presence of virulent strains carrying the thermostable direct hemolysin (tdh) and TDH-related hemolysin genes (trh) using PCR. Of 100 samples, 62 were positive for the presence of V. parahaemolyticus with an MPN (most probable number) value greater than 3.0 (>1100 MPN per g). The PCR analysis revealed 2 samples to be positive for the tdh gene and 11 to be positive for the trh gene. Hence, these results demonstrate the presence of pathogenic V. parahaemolyticus in cockles harvested in the study area and reveal the potential risk of illness associated with their consumption.
    Matched MeSH terms: Hemolysin Proteins
  20. Cross-resistance and inheritance of resistance to Bacillus thuringiensis toxin Cry1Ac in diamondback moth (Plutella xylostella L) from lowland Malaysia
    Sayyed AH, Wright DJ
    Pest Manag Sci, 2001 May;57(5):413-21.
    PMID: 11374157
    A field population of Plutella xylostella from Malaysia (SERD4) was divided into five sub-populations and four were selected (G2-G5) with the Bacillus thuringiensis insecticidal crystal (Cry) toxins Cry1Ac, Cry1Ab, Cry1Ca and Cry1Da. Bioassay at G6 gave resistance ratios of 88, 5, 2 and 3 for Cry1Ac, Cry1Ab, Cry1Ca and Cry1Da respectively compared with the unselected sub-population (UNSEL-SERD4). The Cry1Ac-selected population showed little cross-resistance to Cry1Ab, Cry1Ca and Cry1Da, (3-, 2- and 3-fold compared with UNSEL-SERD4), whereas the Cry1Ab-SEL sub-population showed marked cross-resistance to Cry1Ac (40-fold), much greater than Cry1Ab itself. In contrast, the Cry1Ca- and Cry1Da-SEL sub-population showed little if any cross-resistance to Cry1Ac and Cry1Ab. The mode of inheritance of resistance to Cry1Ac was examined in Cry1Ac-selected SERD4 by standard reciprocal crosses and back-crosses using a laboratory insecticide-susceptible population (ROTH). Logit regression analysis of F1 reciprocal crosses indicated that resistance to Cry1Ac was inherited as an incompletely dominant trait. At the highest dose of Cry1Ac tested, resistance was recessive, while at the lowest dose it was almost completely dominant. The F2 progeny from a back-cross of F1 progeny with ROTH were tested with a concentration of Cry1Ac that would kill 100% of ROTH. The mortality ranged between 50 and 95% in seven families of back-cross progeny, which indicated that more than one allele on separate loci were responsible for resistance to Cry1Ac.
    Matched MeSH terms: Hemolysin Proteins
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