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Articles by Z. Ishak
Total Records ( 5 ) for Z. Ishak
  L.K. Shyuan , L.Y. Heng , M. Ahmad , S.A. Aziz and Z. Ishak
  An bioelectrochemical sensor or biosensor based on the inhibition of the enzyme Alkaline Phosphatase (ALP) has been investigated for the screening of several environmental toxicants. The biosensor was constructed by immobilizing ALP in a hybrid sol-gel/chitosan film that was deposited on the surface of a screen-printed carbon paste electrode (SPE). The inhibition was measured via the catalytic hydrolysis of ascorbic acid 2-phosphate (AA2P) by the enzyme to produce ascorbic acid. Oxidation of this product was monitored amperometrically and the current change was then related to ALP activity. Toxicity of herbicides (2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), insecticides (carbofuran and α-endosulfan) and heavy metals (Hg2+, Cd2+, Ag2+, Zn2+ and Cu2+) towards the biosensor were evaluated. Various degrees of inhibition of ALP occurred when the biosensor was exposed to herbicides and heavy metals. This resulted in a lower acid ascorbic production by the enzyme from the substrate, thus a decrease in the current response of the biosensor. The herbicides 2,4-D and 2,4,5-T showed the largest inhibition effect on ALP with linear response range of 1-60 μg L-1 (R2 = 0.92). The maximum inhibitions caused by 2,4-D and 2,4,5-T were 46 and 30%, respectively. Heavy metals caused inhibition on ALP at the higher concentration range of mg L-1. Thus, the biosensor may be useful for the screening of chlorophenoxyacetic acid herbicides even in the presence of other environmental toxicants.
  Huynh Ky , Le Vinh Thuc , Siew-Eng Ooi , Z. Ishak , P. Namasivayam and S. Napis
  In present study, EgSAPK (EU805512), an oil palm transcript coding for a putative SAPK protein kinase, have been molecular characterized. The cDNA for EgSAPK isolated from an oil palm cell suspension culture is 1470 bp in length with a longest Open Reading Frame (ORF) of 963 bp. No translation start codon could be identified so EgSAPK cDNA sequence is lacking the 5’-end. The deduced protein sequence shares 89% identity with the serine/threonine protein kinase SAPK9 from rice (AB125310.1). Real time PCR results showed that the expression levels of EgSAPK varied in different oil palm tissues and the EgSAPK gene shares a similar expression pattern with the SAPK gene of rice. Furthermore, the transcription of the EgSAPK gene in green embryo, white embryo and embryogenic calli tissues were higher than in non-embryogenic calli tissues. Southern blot analysis showed that the EgSAPK gene might be present as a single copy gene in the oil palm genome. These results suggest that EgSAPK may have a similar function as the SAPK gene of rice and thus can be a candidate marker for oil palm somatic embryogenesis.
  N. Alhaj , N.S. Mariana , A.R. Raha and Z. Ishak
  Antimicrobial agent resistance has been recognized as an emerging worldwide problem in both human and animals, antimicrobial agent use is considered the most important factor for the emergence, selection and dissemination of antimicrobial agent-resistant bacteria, intrinsically either acquires the resistance gene from other bacterial environment or development of pumping out mechanism. The aim of this study was to generate baseline data on the prevalence of antimicrobial resistance in Escherichia coli isolates from different sources. Seventy E. coli isolates from humans and environments were tested for susceptibility to 10 antimicrobial agents by diffusion method. Resistance was found in 61.2% of the isolates. The most prevalent resistances were to kanamycin and tetracycline (81.4%), followed by chloramphenicol (75.7%) and gentamicin, (74.3%). The low prevalent were to cefetoxin (44.3%), norofluoxacin (27.1%) and ciprofluoxacin (24.3%). This study showed the distribution of antimicrobial agent resistance in E. coli isolates from a variety of sources and analysis of such patterns of resistance may prove to be useful beyond simple description. Regarding to the concern of water quality and environmental contamination by human and agricultural waster have increased, it has become increasingly important to develop low-cost screening tools that can be used to identify the most probable source of contamination.
  N. Al Haj , N.S. Mariana , A.R. Raha and Z. Ishak
  Diarrhea is one of the leading causes of illnesses and death among children in developing countries, where an estimated 1.3 billion episodes and 4-10 million deaths occur each year in children below 5 years of age. Escherichia coli strains are among the major bacterial causes of diarrheal illness. There are now 7 classes of diarrheagenic E. coli, namely enteropathogenic E. coli (EPEC), enterohaemorrhagic E. coli (EHEC), enteroinvasive E. coli (EIEC), enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAEC), diarrhea-associated hemolytic E. coli (DHEC) and cytolethal distending toxin (CDT)-producing E. coli. Due to the need for costly and labor-intensive diagnostic procedures, identification of diarrheagenic E. coli (DEC) is difficult at standard laboratories. Therefore, the epidemiology of DEC infections remains an important issues particularly developing country. Recently, Polymerase Chain Reaction (PCR) or dot blot has been used for genetic detection of DEC. In this study, we analyzed 25 E. coli isolates from different sources in Malaysia. Using primers for 671 bp gad gene successfully amplified by PCR. Dot blot analysis for high-throughput, rapid, simple and inexpensive quantification of specific microbial populations was evaluated and used to confirm the results of PCR. The protocol of the assays is readily applicable for implementation in the food processing, water quality control and clinical diagnosis.
  Nagi Ahmed ALHaj , N.S. Mariana , A.R. Raha and Z. Ishak
  Escherichia coli strains are among the major bacterial causes of diarrheal illness. There are now seven classes of diarrheagenic E. coli (DEC), namely enteropathogenic E. coli (EPEC), enterohaemorrhagic E. coli (EHEC), enteroinvasive E. coli (EIEC), enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAEC), diarrhea-associated hemolytic E. coli (DHEC) and Cytolethal Distending Toxin (CDT)-producing E. coli. Due to the need for costly and labor-intensive diagnostic procedures, identification of DEC is difficult at standard laboratories. Therefore, Polymerase Chain Reaction (PCR) or dot blot has been used for genetic detection of DEC of 25 E. coli isolates from different sources. Amplification of eae (277 bp), bfp (266 bp), stx1 (154 bp), EAST (94 bp), stx2 (698 bp) and elt (450 bp) genes of a single product in separate reactions was produced. PCR showed ability to amplify and detected genes of the most common important categories of diarrheagenic E. coli isolates of different sources, it is possible implementation of this technique to diagnosis water, food-borne outbreaks related to E. coli. Dots blot and sequence analysis used to confirm the results of PCR.
 
 
 
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