ORCID Profile
0000-0003-3696-2044
Current Organisations
University of Queensland
,
King Abdulaziz City for Science And Technology
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Publisher: Bangladesh Journals Online (JOL)
Date: 07-2012
Abstract: Seeds of four local wheat (Triticum aestivum L.) cultivars, namely Hinta, Khaliji, Lokaimy and Qasime collected from different regions of Saudi Arabia were exposed to different doses of gamma rays 50-500 Gy to determine suitable doses for induction of mutation. It was observed that seedling height decreased with the increased dose of radiation in all cultivars. Radiosensitive curve originated from seedling height data resulted in 179, 225, 249 and 256 Gys as LD50 values for the cultivars Hinta, Khaliji, Qasime and Lokaimy, respectively. Based on LD50, as to minimize DNA damage and reduce undesirable mutations, radiation doses which lie between 200 and 250 Gy can be considered suitable for induction of mutation in cultivars Lokaimy, Khaliji and Qasime while between 150 and 200 Gy for cultivar Hinta DOI: 0.3329/bjb.v41i1.11075 Bangladesh J. Bot. 41(1): 1-5, 2012 (June)
Publisher: Public Library of Science (PLoS)
Date: 19-04-2018
Publisher: Public Library of Science (PLoS)
Date: 08-04-2021
DOI: 10.1371/JOURNAL.PONE.0249496
Abstract: This study was conducted to determine the susceptibility and resistance of some house fly strains of Musca domestica L. to the insect growth regulator insecticides triflumuron and pyriproxyfen in some locations in Riyadh city. Field-collected strains of M . domestica L. from five sites in Riyadh city that represented five slaughterhouse sites where flies spread significantly were tested against triflumuron and pyriproxyfen. Triflumuron LC 50 values for the five collected strains ranged from 2.6 to 5.5 ppm, and the resistance factors (RFs) ranged from 13-fold to 27-fold that of the susceptible laboratory strain. Pyriproxyfen LC 50 values for the field strains ranged from 0.9 to 1.8 ppm with RFs of 3-fold to 5-fold. These results indicate that pyriproxyfen is an effective insecticide to control house flies and should be used in rotation with other insecticides in the control programs applied by Riyadh municipality.
Publisher: MDPI AG
Date: 17-03-2023
DOI: 10.3390/CIMB45030161
Abstract: Phosphine is the most widely used fumigant for stored grains due to a lack of better alternatives, all of which have serious shortcomings that restrict their use. The extensive use of phosphine has led to the development of resistance among insect pests of grain, which threatens its status as a reliable fumigant. Understanding the mode of action of phosphine as well as its resistance mechanisms provides insight that may lead to improved phosphine efficacy and pest control strategies. The mechanisms of action in phosphine vary from disrupting metabolism and oxidative stress to neurotoxicity. Phosphine resistance is genetically inherited and is mediated by the mitochondrial dihydrolipoamide dehydrogenase complex. In this regard, laboratory studies have revealed treatments that synergistically enhance phosphine toxicity that may be used to suppress resistance development and enhance efficacy. Here, we discuss the reported phosphine modes of action, mechanisms of resistance and interactions with other treatments.
Publisher: University of Queensland Library
Date: 2018
DOI: 10.14264/UQL.2019.76
Publisher: Oxford University Press (OUP)
Date: 10-10-2019
Abstract: Phosphine is the only fumigant approved globally for general use to control insect pests in stored grain. Due to the emergence of resistance among insect pests and the lack of suitable alternative fumigants, we are investigating ways to synergistically enhance phosphine toxicity, by studying the mechanism of action of known synergists, such as oxygen, temperature, and arsenite. Under normoxia, exposure of the model organism Caenorhabditis elegans for 24 h at 20°C to 70 ppm phosphine resulted in 10% mortality, but nearly 100% mortality if the oxygen concentration was increased to 80%. In wild-type C. elegans, toxicity of phosphine was negatively affected by a decrease in temperature to 15°C and positively affected by an increase in temperature to 25°C. The dld-1(wr4) strain of C. elegans is resistant to phosphine due to a mutation in the dihydrolipoamide dehydrogenase gene. It also exhibits increased mortality that is dependent on hyperoxia, when exposed to 70 ppm phosphine at 20°C. As with the wild-type strain, mortality decreased when exposure was carried out at 15°C. At 25°C, however, the strain was completely resistant to the phosphine exposure at all oxygen concentrations. Arsenite is also a synergist of phosphine toxicity, but only in the dld-1(wr4)-mutant strain. Thus, exposure to 4 mM arsenite resulted in 50% mortality, which increased to 89% mortality when 70 ppm phosphine and 4 mM arsenite were combined. In stark contrast, 70 ppm phosphine rendered 4 mM arsenite nontoxic to wild-type C. elegans. These results reveal two synergists with distinct modes of action, one of which targets in iduals that carry a phosphine resistance allele in the dihydrolipoamide dehydrogenase gene.
Publisher: Springer Science and Business Media LLC
Date: 23-04-2019
DOI: 10.1038/S41598-019-42678-W
Abstract: Phosphine gas is an excellent fumigant for disinfesting stored grain of insect pests, but heavy reliance on phosphine has led to resistance in grain pests that threatens its efficacy. Phosphine-resistance was previously reported to be mediated by the enzyme DLD. Here we explore the relationship between phosphine toxicity and genotoxic treatments with the goal of understanding how phosphine works. Specifically, we utilized mutant lines either sensitive or resistant to phosphine, gamma irradiation or UV exposure. The phosphine-resistance mutation in the enzyme of energy metabolism, dihydrolipoamide dehydrogenase exhibited cross-resistance to UV and ionizing radiation. Two radiation-sensitive mutants that are defective in DNA repair as well as a mutant that is defective in the activation of the DAF-16 stress response transcription factor all exhibit sensitivity to phosphine that exceeds the sensitivity of the wild type control. A radiation resistance mutation in cep- 1, the p53 orthologue, that is deficient in double strand break repair of DNA and is also deficient in apoptosis causes radiation-resistance results but sensitivity toward phosphine.
Location: Saudi Arabia
No related grants have been discovered for Saad Alzahrani.