有机磷类神经毒剂及其抗毒剂研究进展

有机磷类神经毒剂以其种类繁多、毒性特殊、使用历史悠久和使用范围广泛,在给人类生产和生活带来益处的同时,也直接或间接地、短期或长期地对人类自身造成危害,为了探索有效防治民用有机磷类神经毒剂的新途径,本文着重就民用有机磷类神经毒剂的主要种类及其特性、作用机理极其体内代谢、危害及其防治的现实意义以及抗毒剂的国内外研究概况和趋势进行了综述。     

肉毒毒素重组抗原表达系统研究进展

肉毒中毒是肉毒杆菌引起的一种致死性的神经麻痹性疾病,应对内毒中毒的最有效方法是预防或疫苗接种,肉毒毒素Hc段是研制亚单位疫苗的首选.通过基因重组技术能够将肉毒毒素Hc片段在大肠杆菌或酵母表达系统中进行大规模表达.阐述了这2种表达载体在肉毒毒素亚单位疫苗的研制及发酵生产情况.     

A型肉毒毒素Hc基因的原核表达、纯化及单抗的制备

在大肠埃希茵中高效表达的重组A型肉毒毒素保护性抗原,是以包涵体形式存在.溶解后的包涵体溶液经过处理,用镍柱亲和层析法纯化,得到纯度约为90%的融合蛋白.利用纯化的重组抗原BoNTa免疫Balb/c小鼠,获得分泌抗BoNTa特异性的3株杂交瘤细胞株2A2、4F7和2A8,其单抗鉴定均为IgG1亚型,滴度达到1:105.高纯度和活性单抗的获得为毒素检测试剂盒的研究奠定了基础.     

Promoting effect of botulinum neurotoxin serotype A heavy chain on neuritogenesis in cultured Neuro-2a cells

AIM: To observe the neuritogenic actions of botulinum neurotoxin serotype A heavy chain (BoNT/A HC) on cultured Neuro-2a cells and to investigate the related signaling mechanisms for the effect of BoNT/A HC. METHODS: Neuro-2a cells were treated with different doses of BoNT/A HC (0.01, 0.1, 1 and 10 nmol/L), and then the cells were harvested at 24 h, 48 h and 72 h of BoNT/A HC exposure for detecting the neurite length and the percen-tage of the cells with neuronal processes by immunofluorescence staining. The most efficient dose of BoNT/A HC was chosen for exposure to Neuro-2a cells as the above. Whole cell protein was harvested at different time points for detecting the protein levels of phosphorylated ERK1/2 (p-ERK1/2) and phosphorylated Akt (p-Akt) by Western blot. RESULTS: Low doses of BoNT/A HC stimulated the neurite outgrowth, and increased the percentage of the cells with neurites compared with the negative controls (P<0.05), especially in the group with 1 nmol/L of BoNT/A HC treatment. Meanwhile, the phosphorylation of ERK1/2 and Akt was increased after treated with BoNT/A HC. There was an increasing tendency for the phosphorylation of ERK1/2 after the exposure of the cells to BoNT/A HC. The obvious increase in p-ERK1/2 was seen from 60 min to 5 h with 1 nmol/L of BoNT/A HC treatment (P< 0.05), and the increased protein level of p-Akt was mainly observed at 15 min and 60 min (P<0.05). CONCLUSION: BoNT/A HC stimulates the neuritogenesis. The neuritogenic mechanism of BoNT/A HC on Neuro-2a cells might be realized by activation of the phosphorylation of ERK1/2 and Akt.     

Current status and future strategy in breeding grasspea (Lathyrus sativus)

Efforts in grasspea (Lathyrus sativus) improvement have increased since the development of lines that are very low in the neurotoxin Beta-N-oxalyl-L-alpha-beta-diamino propionic acid (ODAP); also referred to as Beta-N oxalyl-amino-L-alanine (BOAA). Many programs now address several related aspects of improvement simultaneously. These include reduced ODAP concentrations, insect and disease resistance, nitrogen fixation, agronomic practices, fodder and forage production, and components for increased yielding ability. The coordinated, multidisciplinary approach now being applied to the genetic improvement of grasspea should allow the potential of this largely neglected grain legume to be fully realized.     

Toxic effects of domoic acid in the seabream Sparus aurata

Neurotoxicity induced in fish by domoic acid (DA) was assessed with respect to occurrence of neurotoxic signs, lethality, and histopathology by light microscopy. Sparus aurata were exposed to a single dose of DA by intraperitoneal (i.p.) injection of 0, 0.45, 0.9, and 9.0 mg DA kg(-1) bw. Mortality (66.67 ± 16.67%) was only observed in dose of 9.0 mg kg(-1) bw. Signs of neurological toxicity were detected for the doses of 0.9 and 9.0 mg DA kg(-1) bw. Furthermore, the mean concentrations (±SD) of DA detected by HPLC-UV in extracts of brain after exposure to 9.0 mg DA kg(-1) bw were 0.61 ± 0.01, 0.96 ± 0.00, and 0.36 ± 0.01 mg DA kg(-1) tissue at 1, 2, and 4 hours. The lack of major permanent brain damage in S. aurata, and reversibility of neurotoxic signs, suggest that lower susceptibility to DA or neuronal recovery occurs in affected individuals.     

Botulinum neurotoxin type A heavy chain intervenes in expression of general proteins in spinal cord after unilateral spinal cord injury in rats

AIM: To observe the effect of botulinum neurotoxin type A heavy chain (BoNT/A HC) on the pattern of spinal protein expression by intrathecal injection after spinal cord injury in rats, and to explore the role of BoNT/A HC intervention in spinal protein expression and some of its mechanisms in nerve regeneration after injury. METHODS: The model of unilateral lumbar spinal cord injury was established. The effects of BoNT/A HC intervention at different doses (2 μg, 4 μg, 6 μg and 8 μg) on the general pattern of protein expression in the spinal cord tissues at the injury site and the cranial part adjacent to the injury site was measured and evaluated by SDS-PAGE and Coomassie brilliant blue staining first, and then by two-dimensional SDS-PAGE. RESULTS: The histological structure of the ipsilateral side of lumbar spinal cord showed obvious destruction and degradation, mainly affecting both gray and white matter of the left side of the cord. The result of SDS-PAGE with Coomassie brilliant blue staining from injured spinal cord tissue displayed that the expression of some proteins after one-time BoNT/A HC treatment appeared obviously different from that without BoNT/A HC treatment. Moreover, the pattern of the protein expression affected by BoNT/A HC was similar to that of the normal spinal cord. The more detail information from two-dimensional SDS-PAGE indicated that more than 10 proteins with different molecular weight and isoelectronic points were differentially expressed at day 2 and day 20 after local injection of 6 μg BoNT/A HC. This altered expression actually appeared a tendency toward the pattern shown in normal group. CONCLUSION: The immediate application of BoNT/A HC at the injury site after unilateral lumbar spinal cord injury is able to affect the pattern of local protein expression. The altered protein expression by injury could be reversed back to normal or approximately normal by local BoNT/A HC administration.     

蒲螨利用研究进展

蒲螨是一类寄生鳞翅目、鞘翅目和膜翅目等昆虫的外寄生螨，寄生导致寄主麻痹甚至死亡。本文对蒲螨的分类学、生物学和生态学研究进展、国内外作为天敌的利用情况以及蒲螨体内提取的昆虫特异性神经毒素tox34的使用情况进行了综述。     

肉毒中毒症实验室诊断的研究进展

肉毒中毒症是一种潜在的致死性瘫痪疾病,快速准确的诊断对该病的治疗显得尤为必要。本文综述了肉毒中毒症毒素检测、细菌培养、分子检测、遗传鉴定等实验室诊断的进展情况,以期对本病的快速诊断有所启示。     

Dietary traces of neonicotinoid pesticides as a cause of population declines in honey bees: an evaluation by Hill's epidemiological criteria

BACKGROUND: Honey bees are important pollinators of both crops and wild plants. Pesticide regimes that threaten their sustainability should therefore be assessed. As an example, evidence that the agricultural use of neonicotinoid pesticides is a cause of the recently observed declines in honey bees is examined. The aim is to define exacting demographic conditions for a detrimental factor to precipitate a population decline, and Hill's epidemiological ‘causality criteria’ are employed as a structured process for making an expert judgement about the proposition that trace dietary neonicotinoids in nectar and pollen cause population declines in honey bees. RESULTS: In spite of the absence of decisive experimental results, the analysis shows that, while the proposition is a substantially justified conjecture in the context of current knowledge, it is also substantially contraindicated by a wide variety of circumstantial epidemiological evidence. CONCLUSION: It is concluded that dietary neonicotinoids cannot be implicated in honey bee declines, but this position is provisional because important gaps remain in current knowledge. Avenues for further investigations to resolve this longstanding uncertainty are therefore identified. Copyright © 2012 Society of Chemical Industry