Displaying publications 1 - 20 of 44 in total

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  1. Sayyed AH, Omar D, Wright DJ
    Pest Manag Sci, 2004 Aug;60(8):827-32.
    PMID: 15307676
    Resistance to the bacteria-derived insecticides spinosad (Conserve), abamectin (Vertimec), Bacillus thuringiensis var kurstaki (Btk) (Dipel), B thuringiensis var aizawai (Bta) (Xentari), B thuringiensis crystal endotoxins Cry1Ac and Cry1Ca, and to the synthetic insecticide fipronil was estimated in a freshly-collected field population (CH1 strain) of Plutella xylostella (L) from the Cameron Highlands, Malaysia. Laboratory bioassays at G1 indicated significant levels of resistance to spinosad, abamectin, Cry1Ac, Btk, Cry1Ca, fipronil and Bta when compared with a laboratory insecticide-susceptible population. Logit regression analysis of F1 reciprocal crosses indicated that resistance to spinosad in the CH1 population was inherited as a co-dominant trait. At the highest dose of spinosad tested, resistance was close to completely recessive, while at the lowest dose it was incompletely dominant. A direct test of monogenic inheritance based on a back-cross of F1 progeny with CH1 suggested that resistance to spinosad was controlled by a single locus.
    Matched MeSH terms: Hemolysin Proteins
  2. 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
  3. 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*
  4. 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
  5. Sayyed AH, Raymond B, Ibiza-Palacios MS, Escriche B, Wright DJ
    Appl Environ Microbiol, 2004 Dec;70(12):7010-7.
    PMID: 15574894
    The long-term usefulness of Bacillus thuringiensis Cry toxins, either in sprays or in transgenic crops, may be compromised by the evolution of resistance in target insects. Managing the evolution of resistance to B. thuringiensis toxins requires extensive knowledge about the mechanisms, genetics, and ecology of resistance genes. To date, laboratory-selected populations have provided information on the diverse genetics and mechanisms of resistance to B. thuringiensis, highly resistant field populations being rare. However, the selection pressures on field and laboratory populations are very different and may produce resistance genes with distinct characteristics. In order to better understand the genetics, biochemical mechanisms, and ecology of field-evolved resistance, a diamondback moth (Plutella xylostella) field population (Karak) which had been exposed to intensive spraying with B. thuringiensis subsp. kurstaki was collected from Malaysia. We detected a very high level of resistance to Cry1Ac; high levels of resistance to B. thuringiensis subsp. kurstaki Cry1Aa, Cry1Ab, and Cry1Fa; and a moderate level of resistance to Cry1Ca. The toxicity of Cry1Ja to the Karak population was not significantly different from that to a standard laboratory population (LAB-UK). Notable features of the Karak population were that field-selected resistance to B. thuringiensis subsp. kurstaki did not decline at all in unselected populations over 11 generations in laboratory microcosm experiments and that resistance to Cry1Ac declined only threefold over the same period. This finding may be due to a lack of fitness costs expressed by resistance strains, since such costs can be environmentally dependent and may not occur under ordinary laboratory culture conditions. Alternatively, resistance in the Karak population may have been near fixation, leading to a very slow increase in heterozygosity. Reciprocal genetic crosses between Karak and LAB-UK populations indicated that resistance was autosomal and recessive. At the highest dose of Cry1Ac tested, resistance was completely recessive, while at the lowest dose, it was incompletely dominant. A direct test of monogenic inheritance based on a backcross of F1 progeny with the Karak population suggested that resistance to Cry1Ac was controlled by a single locus. Binding studies with 125I-labeled Cry1Ab and Cry1Ac revealed greatly reduced binding to brush border membrane vesicles prepared from this field population.
    Matched MeSH terms: Hemolysin Proteins
  6. Sayyed AH, Haward R, Herrero S, Ferré J, Wright DJ
    Appl Environ Microbiol, 2000 Apr;66(4):1509-16.
    PMID: 10742234
    Four subpopulations of a Plutella xylostella (L.) strain from Malaysia (F(4) to F(8)) were selected with Bacillus thuringiensis subsp. kurstaki HD-1, Bacillus thuringiensis subsp. aizawai, Cry1Ab, and Cry1Ac, respectively, while a fifth subpopulation was left as unselected (UNSEL-MEL). Bioassays at F(9) found that selection with Cry1Ac, Cry1Ab, B. thuringiensis subsp. kurstaki, and B. thuringiensis subsp. aizawai gave resistance ratios of >95, 10, 7, and 3, respectively, compared with UNSEL-MEL (>10,500, 500, >100, and 26, respectively, compared with a susceptible population, ROTH). Resistance to Cry1Ac, Cry1Ab, B. thuringiensis subsp. kurstaki, and B. thuringiensis subsp. aizawai in UNSEL-MEL declined significantly by F(9). The Cry1Ac-selected population showed very little cross-resistance to Cry1Ab, B. thuringiensis subsp. kurstaki, and B. thuringiensis subsp. aizawai (5-, 1-, and 4-fold compared with UNSEL-MEL), whereas the Cry1Ab-, B. thuringiensis subsp. kurstaki-, and B. thuringiensis subsp. aizawai-selected populations showed high cross-resistance to Cry1Ac (60-, 100-, and 70-fold). The Cry1Ac-selected population was reselected (F(9) to F(13)) to give a resistance ratio of >2,400 compared with UNSEL-MEL. Binding studies with (125)I-labeled Cry1Ab and Cry1Ac revealed complete lack of binding to brush border membrane vesicles prepared from Cry1Ac-selected larvae (F(15)). Binding was also reduced, although less drastically, in the revertant population, which indicates that a modification in the common binding site of these two toxins was involved in the resistance mechanism in the original population. Reciprocal genetic crosses between Cry1Ac-reselected and ROTH insects indicated that resistance was autosomal and showed incomplete dominance. At the highest dose of Cry1Ac tested, resistance was recessive while at the lowest dose it was almost completely dominant. The F(2) progeny from a backcross of F(1) progeny with ROTH was tested with a concentration of Cry1Ac which would kill 100% of ROTH moths. Eight of the 12 families tested had 60 to 90% mortality, which indicated that more than one allele on separate loci was responsible for resistance to Cry1Ac.
    Matched MeSH terms: Hemolysin Proteins
  7. Vinazzer H
    Subsid Med, 1974;4:53-5.
    PMID: 4450561
    Matched MeSH terms: Hemolysin Proteins/pharmacology*; Hemolysin Proteins/therapeutic use*
  8. 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
  9. Chai PF, Rathinam X, Solayappan M, Ahmad Ghazali AH, Subramaniam S
    Microscopy (Oxf), 2014 Oct;63(5):371-5.
    PMID: 24943903 DOI: 10.1093/jmicro/dfu022
    The current study focused on the microscopic studies of a native Bacillus thuringiensis strain isolated from Malaysia, Bt-S84-13a, that produced an unusual crystal type. Primary detection of parasporal inclusions using a phase contrast microscope presented one to two small crystal proteins in the sporulating cells of Bt-S84-13a. Compound light microscopic examination of autolysed Bt-S84-13a cells stained with 0.133% Coomassie Brilliant Blue showed two types of crystal morphology: small crystals independent of spores and spore-associated crystals. Surface structure analysis with a scanning electron microscope revealed spherical-like, coarse and wrinkled-looking crystal in Bt-S84-13a. A close-up observation of the crystal morphology using a transmission electron microscope also demonstrated two parasporal inclusions in Bt-S84-13a. One inclusion was deposited against the forespore and was in a shape of incomplete rectangular. Another smaller inclusion was developed within the exosporium and was rectangular in shape. However, the latter inclusion was found lack in another bacterial cell which was still in the early stages of sporulation. This unique crystal morphology may imply some biological potential in Bt-S84-13a.
    Matched MeSH terms: Hemolysin Proteins/ultrastructure
  10. Subrahmanyam C
    Med J Malaya, 1966 Mar;20(3):234-9.
    PMID: 4223073
    Matched MeSH terms: Hemolysin Proteins/pharmacology*
  11. Lakxmy AP, Xavier R, Reenajosephine CM, Lee YW, Marimuthu K, Kathiresan S, et al.
    Eur Rev Med Pharmacol Sci, 2011 Feb;15(2):149-55.
    PMID: 21434481
    To evaluate the mosquito larvicidal potential of the native Bacillus thuringiensis isolate BtReXO2, which was isolated from a tropical rain forest ecosystem in Malaysia. This study also aimed at determining the phenotypic and biochemical characteristics of the isolate.
    Matched MeSH terms: Hemolysin Proteins/pharmacology*
  12. Yousr, A.H., Nipis, S., Rusul, G.R.A., Son, R.
    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
  13. 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
  14. Shuan Ju Teh C, Lin Thong K, Tein Ngoi S, Ahmad N, Balakrish Nair G, Ramamurthy T
    J Gen Appl Microbiol, 2009 Dec;55(6):419-25.
    PMID: 20118606
    A pair of primers targeting the hlyA gene for Vibrio cholerae which could distinguish the classical from El Tor biotypes was designed and combined with other specific primers for ompW, rfb complex, and virulence genes such as ctxA, toxR, and tcpI in a multiplex PCR (m-PCR) assay. This m-PCR correctly identified 39 V. cholerae from clinical, water and seafood samples. The efficiency of this multiplex PCR (m-PCR) was compared with conventional biochemical and serogrouping methods. One O139 and 25 O1 V. cholerae strains including 10 environmental strains harbored all virulence-associated genes except 1 clinical strain which only had toxR and hlyA genes. Thirteen environmental strains were classified as non-O1/non-O139 and had the toxR and hlyA genes only. The detection limit of m-PCR was 7 x 10(4) cfu/ml. The m-PCR test was reliable and rapid and reduced the identification time to 4 h.
    Matched MeSH terms: Hemolysin Proteins/genetics*; Hemolysin Proteins/chemistry
  15. Iyer L, Vadivelu J, Puthucheary SD
    Epidemiol Infect, 2000 Aug;125(1):27-34.
    PMID: 11057956
    Eighty-four strains of Vibrio cholerae O1, O139 and non-O1/non-O139 from clinical and environmental sources were investigated for the presence of the toxin co-regulated pilus gene, tcpA, the virulence cassette genes ctxA, zot, ace and cep and also for their ability to elaborate haemolysin and protease. The ctxA and zot genes were detected using DNA-DNA hybridization while the ace, cep and tcpA genes were detected using PCR. Production of haemolysin and protease was detected using mammalian erythrocytes and an agar diffusion assay respectively. Analysis of their virulence profiles showed six different groups designated Type I to Type VI and the major distinguishing factor among these profiles was in the in vitro production of haemolysin and/or protease. Clinical O1, O139 and environmental O1 strains were similar with regard to presence of the virulence cassette genes. All environmental O1 strains with the exception of one were found to possess ctxA, zot and ace giving rise to the probability that these strains may actually be of clinical origin. One strain which had only cep but none of the toxin genes may be a true environmental isolate. The virulence cassette and colonization factor genes were absent in all non-O1/non-O139 environmental strains but production of both the haemolysin and protease was present, indicating that these may be putative virulence factors. These findings suggest that with regard to its pathogenic potential, only strains of the O1 and O139 serogroup that possess the tcpA gene which encodes the phage receptor, have the potential to acquire the CTX genetic element and become choleragenic.
    Matched MeSH terms: Hemolysin Proteins/analysis; Hemolysin Proteins/biosynthesis*
  16. Vadivelu J, Puthucheary SD, Mitin A, Wan CY, van Melle B, Puthucheary JA
    PMID: 9031414
    Forty clinical isolates of Vibrio parahaemolyticus were studied for the production of the thermostable direct hemolysin (TDH), and the TDH-related hemolysin (TRH) including the respective encoding genes, tdh and trh. The presence of TDH and its encoding genes were found amongst 95% of the strains, whereas the TRH was absent amongst these isolates. Thirty-two isolates were found to be plasmid-free, whereas eight isolates possessed plasmids with sizes ranging from 2.4 > or = 23 kb. Using a DNA probe coding for the homologous region of the tdh and trh, it was found that the tdh genes were present on the chromosomal DNA.
    Matched MeSH terms: Hemolysin Proteins/blood*
  17. Franklin F, Chong CW, Chua LH, Anthony AA, Liew MWO, Aziah I, et al.
    Med Microbiol Immunol, 2020 Oct;209(5):593-601.
    PMID: 32246197 DOI: 10.1007/s00430-020-00667-1
    Typhoid fever is a disease caused by Salmonella Typhi that was implicated in millions of illnesses worldwide annually. Individuals that do not recover fully from typhoid fever can become asymptomatic carriers of the disease. Host antibodies against the S. Typhi antigens, HlyE (for acute typhoid) and YncE (for carriers) were previously reported to be useful biomarkers for the disease. Here, we expressed and purified recombinant HlyE and YncE antigens and tested the IgG, IgA and IgM responses in 422 sera samples retrieved from acute typhoid patients, other febrile, food handlers, and healthy individuals. The results showed that HlyE-IgG, -IgA and -IgM ELISAs have a collective sensitivity of 83% while YncE-IgG and -IgA ELISAs identified 16 possible carriers based on their antibody profiles. The identification of sensitive biomarkers for typhoid carrier detection is crucial for disease eradication.
    Matched MeSH terms: Hemolysin Proteins/immunology*
  18. Farra Amira Mohamed, Aimi Nadia Ramli,, Noorlis Ahmad
    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
  19. 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. Vadivelu J, Puthucheary SD, Navaratnam P
    Singapore Med J, 1992 Aug;33(4):375-7.
    PMID: 1411668
    The haemolysins produced by Aeromonas species were detected and compared by two assay methods--a modified blood agar plate assay and the rabbit erythrocyte haemolysin method. Both assays showed a high level of agreement (86%). The titres of the rabbit erythrocyte haemolysin assay correlated with the haemolytic zone diameter of the ox blood agar assay. In addition the agar haemolysin assay had simple media requirements, was easy to perform and results were well defined.
    Matched MeSH terms: Hemolysin Proteins/analysis*
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