Cry8E亚致死浓度对马铃薯甲虫解毒酶和保护酶的影响

苏云金芽胞杆菌Cry8E杀虫晶体蛋白对马铃薯甲虫具有中等毒性,用亚致死剂量9和7μg/m L的Cry8E分别饲喂2、3和4龄的马铃薯甲虫幼虫,然后测定羧酸酯酶(Car E)、乙酰胆碱酯酶(ACh E)、谷胱甘肽-S-转移酶(GST)和过氧化氢酶(CAT)的酶活性。β-羧酸酯酶的活性随Cry8E浓度的升高明显提高,随龄期增长活性降低,酶活性在浓度间和龄期间差异都极显著。谷胱甘肽-S-转移酶活性下降,2龄幼虫体内的乙酰胆碱酯酶的活性明显升高,并且随龄期变化差异显著(P0.01)。3龄幼虫体内的CAT酶活性随Cry8E浓度的增加而显著升高(P0.01)。本研究阐明了Cry8E对马铃薯甲虫解毒酶和保护酶活性的影响,为理论研究奠定基础。     

Antioxidant and enzyme inhibition activities and chemical profiles of Polygonum sachalinensis F.Schmidt ex Maxim (Polygonaceae)

Polygonum sachalinensis is a widespread invasive plant in Europe. Chemical profiles of its different organs were studied by HPLC-UV-ESI/MS. Seven major constituents quercetin-3-O-β-D-galactopyranoside, quercetin-3-O-arabinopyranoside, lapathoside D, N-trans-feruloyltyramine, lapathoside C, hydropiperoside, and vanicoside B were isolated and identified. The free radical-scavenging, α/β-glucosidase, and acetylcholinesterase inhibitory activities of crude MeOH extracts and isolated compounds were studied. The structure–activity relationships were discussed. The chemical profiles revealed flavonoids and phenylpropanoids are the major compounds of all the organs of this plant. Quercetin-3-O-arabinopyranoside, lapathoside D, N-trans-feruloyltyramine, lapathoside C and hydropiperoside were isolated from this species for the first time. In the α-glucosidase bioassay, quercetin-3-O-β-D-galactopyranoside, lapathoside D and N-trans-feruloyltyramine demonstrated stronger activities than the positive reference acarbose. The trend in scavenging power showed no relation to enzyme inhibition in the test models.     

家蚕耐氟与敏感品种乙酰胆碱酯酶的比较研究

用浸叶法添氟以检测氟对家蚕乙酰胆碱酯酶的影响。实验结果显示,添氟后蚕体乙酰胆碱酯酶活性降低,耐氟品种添氟组与对照组差距小于敏感品种;耐氟品种添氟后酶原蛋白含量高于对照组,敏感品种酶原蛋白含量始终低于对照组。研究结果表明,耐氟品种通过乙酰胆碱酯酶基因表达量的增加弥补了氟对乙酰胆碱酯酶活性的影响,使乙酰胆碱酯酶活性总体持平,从而使家蚕产生耐氟性。     

The Effect of Chemical Composition and Bioactivity of Several Essential Oils on Tenebrio molitor (Coleoptera: Tenebrionidae)

The major chemical components of four essential oils (EOs) extracted from dry leaves of Citrus limonum, Cymbopogon citratus, Litsea cubeba, and Muristica fragrans were analyzed with gas chromatograph-mass spectrometer and their fumigant, contact, and repellent activities against 10th instar and adults of Tenebrio molitor were also assayed. The results indicated that the major constituents of C. limonum and Cy. citrates were D-limonene (38.22%) and 3,7-dimethyl-6-octenal (26.21%), while which of L. cubeba and M. fragrans were (E)-3, 7-dimethyl-2, 6-octadienal (49.78%) and (E)-cinnamaldehyde (79.31%), respectively. Contact activities of L. cubeba and C. limonum with LC₅₀ values of 21.2 and 13.9 µg/cm² at 48 h and repellence activities (>89.0% repellence indexes) (P < 0.05) at 12 h on 10th instar were better than those of the other two EOs. Nevertheless, the fumigation activities of L. cubeba on 10th instar and adults (LC₅₀ = 2.7, 3.7 μl/liter) were stronger than those of C. limonum (LC₅₀ = 10.9, 12.0 μl/liter) at 96 h and significant (not overlapping confidence intervals). The EOs of L. cubeba and C. limonum have clearly elongated the growth and development of larvae, egg, and slightly shorten pupae and adults of T. molitor compared with the control. The mainly active ingredients of L. cubeba and C. limonum, including D-limonene and β-pinene, were demonstrated to coinhibit the actives of AChE and enhance the toxicities on 10th instar of T. molitor. These results indicate that the EOs of L. cubeba and C. limonum could have great potential as botanical insecticides against T. molitor.     

Fluoride-induced brain damages in suckling mice

In order to reveal mechanisms of brain damages resulted from fluoride toxicity, we treated adult female mice of Swiss Albinos strain by 500 ppm NaF (226 ppm F⁻) in their drinking water from the 15th day of pregnancy until the day 14 after delivery. All mice were sacrificed on day 14 after parturition. During treatment, levels of thiobarbituric acid reactive substances (TBARS), the marker of lipid peroxidation extend, increased, while the activities of the antioxidant enzymes such as glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT), and the level of glutathione (tGSH) decreased significantly in both cerebellum and cerebrum compared with those of the control group. These results suggested that fluoride enhanced oxidative stress in the brain, thereby disturbing the antioxidant defense of nursing pups. In addition, acetylcholinesterase (AChE) activity in both cerebellum and cerebrum was inhibited after treatment with fluoride. In our previous studies we have found, a decrease in plasma thyroid hormone levels of nursing pups whose mothers were treated by NaF. In cerebellum of mice, migration of neurons from the external granular layer to the internal granular layer occurred postnatally and was dependent upon the presence of thyroid hormone. In hypothyroidism, several neurons failed to complete their migration and died. Key guidance signals to these migrating neurons were provided by laminin, an extracellular matrix protein fixed to the surface of astrocytes. In the present study we examined the expression and distribution of laminin in cerebellum of 14-day-old mice. Immunoreactive laminin was disappeared by postnatal day 14 in cerebellum parenchyma of control pups and was restricted to vasculature despite the continued presence of granular cells in the external granular layer. In contrast, in cerebellum of NaF treated pups, laminin was deposited in organised punctuate clusters in the molecular layer. These data indicated that the disruption of laminin distribution might play a major role in the profound derangement of neuronal migration observed in cerebellum of NaF treated pups.     

Effect of ginger supplementation on developmental toxicity induced by fenitrothion insecticide and/or lead in albino rats

Evaluation of the antioxidant and antiteratogenic role of ginger Zingiber officinale polyphenols against the toxicity induced by fenitrothion and/or lead in female albino rats were investigated. Adult virgin females were divided into 8 groups and were orally treated as follow: control (C), 1% w/w of ginger (G), 120 μg/animal lead as lead acetate (L), 10 mg/kg of fenitrothion (F), lead (120 μg/animal) fenitrothion (10 mg/kg) (LF), ginger (1%w/w) + fenitrothion (10 mg/kg) (GF), ginger (1%w/w) + lead (120 μg/animal) (GL), ginger (1%w/w) + lead (120 μg/animal) + fenitrothion (10 mg/kg) (GLF). Treatments were expanded for 28 days before pregnancy and during gestation period from zero to 6th day. Blood samples were taken at the day 20th of gestation and animals were sacrificed to investigate the effect of tested substances on dams and development of their fetuses. Inhibition in AchE in (F) and (LF) groups and elevation in plasma AchE in (L) groups were observed. Elevation in oxidative stress biomarker malondialdehyde (MDA) was recorded in all intoxicated groups concomitants with reduction in total reduced glutathione (GSH) and reduction in the activity of glutathione S-transferase (GST). Elevation in liver function biomarkers alanin amintransferase (ALT) and aspartate aminotransferase (AST) and reduction in plasma total protein and albumin were recorded in (F), (L) and (LF). Supplementation with ginger in diet attenuates the alteration in MDA, GSH, GST, ALT and AST, however, it failed to counteract the effect of F, L and LF on AchE, total protein and albumin. Significant alterations in maternal toxicity were recorded in (GF, GL, LF and GLF) compared with control group. Also, parameters of embryotoxicity and fetotoxicity indicated significant decrease in litter number that observed in F and L and the number of dead fetus/dam and litters number increased in L group. Supplementation with ginger decreased each of the number of died fetus, growth retardation and fetal length, while, it increased fetal weight. As regards to, teratological aspects, the percentage of skeletal malformations and visceral anomalies were observed in all feti obtained from treated groups with different percentages. Supplementation with ginger slightly attenuates the developmental toxicity of fenitrothion and/or lead.     

麦穗鱼脑乙酰胆碱酯酶(AChE)的纯化及其比较性研究

用PEG2000双水相萃取、DEAE-Sephadex A-50和Sephadex G-200方法分离纯化麦穗鱼Pseudorasbora parva脑中的乙酰胆碱酯酶(AChE),然后比较分析纯酶液与粗酶液中鱼脑AChE 的动力学特性和抗抑制性,以便更直接地了解底物与酶以及毒剂与酶的反应关系。研究结果表明,经过一系列步骤的纯化,最后所得的AChE是纯度较高的酶液;通过对AChE的动力学研究发现,纯化后的麦穗鱼脑AChE与底物之间的亲和力和其在粗酶状态时没有显著的差别,而且纯化后的鱼脑AChE对底物抑制作用更敏感;抗抑制性研究发现,纯化后的麦穗鱼脑AChE对经溴水氧化的马拉硫磷(malathion)和三唑磷(triazophos)的敏感性显著高于粗酶状态的AChE,酶更易受抑制。     

Cloning of the acetylcholinesterase 1 gene and identification of point mutations putatively associated with carbofuran resistance in Nilaparvata lugens

Molecular mechanisms of carbofuran resistance in the brown planthopper, Nilaparvata lugens Stål, were investigated. A carbofuran-resistant strain (CAS) showed approximately 45.5- and 15.1-fold resistance compared with a susceptible strain (SUS) and a non-selected field strain (FM), respectively. Activities of the esterase and mixed-function oxidase were approximately 2.8- and 1.6-fold higher, respectively, in the CAS strain than in the SUS strain, suggesting that these enzymes play a minor role in carbofuran resistance. Interestingly, the insensitivity of acetylcholinesterase (AChE) to carbofuran was approximately 5.5- and 3.7-fold higher in the CAS strain compared to the SUS and FM strains, respectively, indicating that AChE insensitivity is associated with carbofuran resistance. Western blot analysis identified two kinds of AChEs, of which the type-1 AChE (encoded from Nlace1, which is paralogous to the Drosophila AChE gene) was determined to be the major catalytic AChE in N. lugens. The open reading frame of Nlace1 is composed of 1989 bp (approximately 74 kD) and revealed 52.5% and 24.3% amino acid sequence identities to those of Nephotettix cincticeps and Drosophila melanogaster, respectively. Screening of point mutations identified four amino acid substitutions (G119A, F/Y330S, F331H and H332L) in the CAS strain that likely contribute to AChE insensitivity. The frequencies of these mutations were well correlated with resistance levels, confirming that they are associated with reduced sensitivity to carbofuran in N. lugens. These point mutations can be useful as genetic markers for monitoring resistance levels in field populations of N. lugens.     

Variation in the sensitivity of Callosobruchus (Coleoptera: Bruchidae) acetylcholinesterase to the organophosphate insecticide malaoxon: effect of species, geographical strain and food type

BACKGROUND: Bruchid beetles, Callosobruchus species, are serious pests of economically important grain legumes; their activity in stores is often controlled by the use of synthetic insecticides. Esterases are known to be involved in insecticide resistance in insects. However, there is a dearth of information on esterase activity in the genus Callosobruchus. In this study, the effect of species, geographical strain and food type on the variation in acetylcholinesterase (AChE) activity and its inhibition by malaoxon (malathion metabolite) was investigated using an in vitro spectrophotometric method. RESULT: AChE activity varied significantly among species and strains and also among legume type used for rearing them. Generally, irrespective of species, strain or food type, the higher the AChE activity of a population, the higher is its inhibition by malaoxon. C. chinensis had the highest AChE activity of the species studied, and in the presence of malaoxon it had the lowest remaining AChE activity, while C. rhodesianus retained the highest activity. CONCLUSION: A first‐hand knowledge of AChE activity in regional Callosobruchus in line with the prevailing food types should be of utmost importance to grain legume breeders, researchers on plant materials for bruchid control and pesticide manufacturer/applicators for a robust integrated management of these bruchids. Copyright © 2012 Society of Chemical Industry