Displaying publications 21 - 32 of 32 in total

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  1. 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: Endotoxins/toxicity*
  2. Lim FL, Hashim Z, Than LTL, Md Said S, Hashim JH, Norbäck D
    Int J Tuberc Lung Dis, 2019 11 01;23(11):1171-1177.
    PMID: 31718753 DOI: 10.5588/ijtld.18.0668
    OBJECTIVE: To examine the associations between endotoxin and (1,3)-β-glucan concentrations in office dust and respiratory symptoms and airway inflammation among 695 office workers in Malaysia.METHODS: Health data were collected using a questionnaire, sensitisation testing and measurement of fractional exhaled nitric oxide (FeNO). Indoor temperature, relative air humidity (RH) and carbon dioxide (CO₂) were measured in the offices and settled dust was vacuumed and analysed for endotoxin and (1,3)-β-glucan concentrations. Associations were analysed by two level multiple logistic regression.RESULTS: Overall, 9.6% of the workers had doctor-diagnosed asthma, 15.5% had wheeze, 18.4% had daytime attacks of breathlessness and 25.8% had elevated FeNO (≥25 ppb). The median levels in office dust were 11.3 EU/mg endotoxin and 62.9 ng/g (1,3)-β-glucan. After adjusting for personal and home environment factors, endotoxin concentration in dust was associated with wheeze (P = 0.02) and rhinoconjunctivitis (P = 0.007). The amount of surface dust (P = 0.04) and (1,3)-β-glucan concentration dust (P = 0.03) were associated with elevated FeNO.CONCLUSION: Endotoxin in office dust could be a risk factor for wheeze and rhinoconjunctivitis among office workers in mechanically ventilated offices in a tropical country. The amount of dust and (1,3)-β-glucan (a marker of indoor mould exposure) were associated with Th2 driven airway inflammation.
    Matched MeSH terms: Endotoxins/analysis*
  3. Barloy F, Lecadet MM, Delécluse A
    Gene, 1998 May 12;211(2):293-9.
    PMID: 9602158
    Three new open reading frames were found downstream from cbm71, a toxin gene from Clostridium bifermentans malaysia (Cbm) strain CH18. The first one (91bp downstream) called cbm72, is 1857bp long and encodes a 71727-Da protein (Cbm72) with a sequence similar to that of Bacillus thuringiensis delta-endotoxins. This protein shows no significant toxicity to mosquito larvae. The two others, cbm17.1 (462bp) and cbm17.2 (459bp), are copies of the same gene encoding Cbm P18 and P16 polypeptides and located 426bp and 1022bp downstream from cbm72, respectively. They encode 17189-Da and 17451-Da proteins with sequences 44.6% similar to that of Aspergillus fumigatus hemolysin; however, they were not hemolytic in the conditions tested.
    Matched MeSH terms: Endotoxins/genetics
  4. 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: Endotoxins/toxicity
  5. 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: Endotoxins/pharmacology*
  6. Xi Loh EY, Fauzi MB, Ng MH, Ng PY, Ng SF, Ariffin H, et al.
    ACS Appl Mater Interfaces, 2018 Nov 21;10(46):39532-39543.
    PMID: 30372014 DOI: 10.1021/acsami.8b16645
    The evaluation of the interaction of cells with biomaterials is fundamental to establish the suitability of the biomaterial for a specific application. In this study, the properties of bacterial nanocellulose/acrylic acid (BNC/AA) hydrogels fabricated with varying BNC to AA ratios and electron-beam irradiation doses were determined. The manner these hydrogel properties influence the behavior of human dermal fibroblasts (HDFs) at the cellular and molecular levels was also investigated, relating it to its application both as a cell carrier and wound dressing material. Swelling, hardness, adhesive force (wet), porosity, and hydrophilicity (dry) of the hydrogels were dependent on the degree of cross-linking and the amount of AA incorporated in the hydrogels. However, water vapor transmission rate, pore size, hydrophilicity (semidry), and topography were similar between all formulations, leading to a similar cell attachment and proliferation profile. At the cellular level, the hydrogel demonstrated rapid cell adhesion, maintained HDFs viability and morphology, restricted cellular migration, and facilitated fast transfer of cells. At the molecular level, the hydrogel affected nine wound-healing genes (IL6, IL10, MMP2, CTSK, FGF7, GM-CSF, TGFB1, COX2, and F3). The findings indicate that the BNC/AA hydrogel is a potential biomaterial that can be employed as a wound-dressing material to incorporate HDFs for the acceleration of wound healing.
    Matched MeSH terms: Endotoxins/chemistry
  7. 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: Endotoxins
  8. Norbäck D, Hashim JH, Markowicz P, Cai GH, Hashim Z, Ali F, et al.
    Sci Total Environ, 2016 Mar 1;545-546:95-103.
    PMID: 26745297 DOI: 10.1016/j.scitotenv.2015.12.072
    This paper studied associations between ocular symptoms, rhinitis, throat and dermal symptoms, headache and fatigue in students by ethnicity and in relation to exposure to chemical microbial markers and fungal DNA in vacuumed dust in schools in Malaysia. A total of 462 students from 8 randomly selected secondary schools in Johor Bahru, Malaysia, participated (96% response rate). Dust was vacuumed from 32 classrooms and analysed for levels of five types of endotoxin as 3-hydroxy fatty acids (C10, C12, C14, C16 and C18 3-OH), muramic acid, ergosterol and five sequences of fungal DNA. Multiple logistic regression was applied. Totally 11.9% reported weekly ocular symptoms, 18.8% rhinitis, 15.6% throat and 11.1% dermal symptoms, 20.6% headache and 22.1% tiredness. Totally 21.1% reported pollen or furry pet allergy (atopy) and 22.0% parental asthma or allergy. Chinese students had less headache than Malay and Indian had less rhinitis and less tiredness than Malay. Parental asthma/allergy was a risk factor for ocular (odds ratio=3.79) and rhinitis symptoms (OR=3.48). Atopy was a risk factor for throat symptoms (OR=2.66), headache (OR=2.13) and tiredness (OR=2.02). There were positive associations between amount of fine dust in the dust samples and ocular symptoms (p<0.001) and rhinitis (p=0.006). There were positive associations between C14 3-OH and rhinitis (p<0.001) and between C18 3-OH and dermal symptoms (p=0.007). There were negative (protective) associations between levels of total endotoxin (LPS) (p=0.004) and levels of ergosterol (p=0.03) and rhinitis and between C12 3-OH and throat symptoms (p=0.004). In conclusion, the amount of fine dust in the classroom was associated with rhinitis and other SBS symptoms and improved cleaning of the schools is important. Endotoxin in the school dust seems to be mainly protective for rhinitis and throat symptoms but different types of endotoxin could have different effects. The ethnic differences in symptoms among the students deserve further attention.
    Matched MeSH terms: Endotoxins
  9. Wirjon IA, Lau NS, Arip YM
    Intervirology, 2016;59(5-6):243-253.
    PMID: 28384626 DOI: 10.1159/000468987
    OBJECTIVES: Phage pPM_01 was previously isolated from a raw sewage treatment facility located in Batu Maung, Penang, Malaysia, and it was highly lytic against Proteus mirabilis, which causes urinary tract infections in humans. In this paper, we characterize the biology and complete genome sequence of the phage.

    METHODS AND RESULTS: Transmission electron microscopy revealed phage pPM_01 to be a siphovirus (the first reported virus to infect P. mirabilis), with its complete genome sequence successfully determined. The genome was sequenced using Illumina technology and the reads obtained were assembled using CLC Genomic Workbench v.7.0.3. The whole genome contains a total of 58,546 bp of linear double-stranded DNA with a G+C content of 46.9%. Seventy putative genes were identified and annotated using various bioinformatics tools including RAST, Geneious v.R7, National Center for Biotechnology Information (NCBI) BLAST, and tRNAscan-SE-v1.3 Search. Functional clusters of related potential genes were defined (structural, lytic, packaging, replication, modification, and modulatory). The whole genome sequence showed a low similarity to known phages (i.e., Enterobacter phage Enc34 and Enterobacteria phage Chi). Host range determination and SDS-PAGE analysis were also performed.

    CONCLUSIONS: The inability to lysogenize a host, the absence of endotoxin genes in the annotated genome, and the lytic behavior suggest phage pPM_01 as a possible safe biological candidate to control P. mirabilis infection.

    Matched MeSH terms: Endotoxins
  10. 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: Endotoxins
  11. Chan KK, Wong RS, Mohamed SM, Ibrahim TA, Abdullah M, Nadarajah VD
    PMID: 22591286
    Bacillus thuringiensis (Bt) parasporal proteins with selective anticancer activity have recently garnered interest. This study determines the efficacy and mode of cell death of Bt 18 parasporal proteins against 3 leukemic cell lines (CEM-SS, CCRF-SB and CCRF-HSB-2).Cell-based biochemical analysis aimed to determine cell viability and the percentage of apoptotic cell death in treated cell lines; ultrastructural analysis to study apoptotic changes and Western blot to identify the parasporal proteins' binding site were performed. Bt 18 parasporal proteins moderately decreased viability of leukemic cells but not that of normal human T lymphocytes. Further purification of the proteins showed changes in inhibition selectivity. Phosphatidylserine externalization, active caspase-3, cell cycle, and ultrastructural analysis confirmed apoptotic activity and S-phase cell-cycle arrest. Western blot analysis demonstrated glyceraldehyde 3-phosphate dehydrogenase as a binding protein. We suggest that Bt 18 parasporal proteins inhibit leukemic cell viability by cell-cycle arrest and apoptosis and that glyceraldehyde 3-phosphate dehydrogenase binding initiates apoptosis.
    Matched MeSH terms: Endotoxins/pharmacology
  12. Lin X, Liu X, Xu J, Cheng KK, Cao J, Liu T, et al.
    Chin Med, 2019;14:18.
    PMID: 31080495 DOI: 10.1186/s13020-019-0240-2
    Background: Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder, which is commonly treated with antidiarrhoeal, antispasmodics, serotonergic agents or laxative agents. These treatments provide relief for IBS symptoms but may also lead to undesired side effects. Previously, herb-partitioned moxibustion (HPM) treatment has been demonstrated to be effective in ameliorating symptoms of IBS. However, the underlying mechanism of this beneficial treatment is yet to be established. The aim of the current study was to systematically assess the metabolic alterations in response to diarrhea-predominant IBS (IBS-D) and therapeutic effect of HPM.

    Methods: Proton nuclear magnetic resonance spectroscopy (1H NMR)-based metabolomics approach was used to investigate fecal and serum metabolome of rat model of IBS-D with and without HPM treatment.

    Results: The current results showed that IBS-induced metabolic alterations in fecal and serum sample include higher level of threonine and UDP-glucose together with lower levels of aspartate, ornithine, leucine, isoleucine, proline, 2-hydroxy butyrate, valine, lactate, ethanol, arginine, 2-oxoisovalerate and bile acids. These altered metabolites potentially involve in impaired gut secretory immune system and intestinal inflammation, malabsorption of nutrients, and disordered metabolism of bile acids. Notably, the HPM treatment was found able to normalize the Bristol stool forms scale scores, fecal water content, plasma endotoxin level, and a number of IBS-induced metabolic changes.

    Conclusions: These findings may provide useful insight into the molecular basis of IBS and mechanism of the HPM intervention.

    Matched MeSH terms: Endotoxins
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