三聚氰胺对小鼠肾脏病理损伤的初步观察

为观察三聚氰胺对小鼠肾脏病理损伤情况,以浓度700、350、175mg/kg体重给28天昆明小鼠连续灌胃,玉米油做溶剂,观察肾脏组织病理学变化及细胞化学变化。结果发现,三聚氰胺可引起小鼠肾脏肾小管管腔中出现黄色或棕黄色结晶,肾小管上皮细胞变性、坏死,细胞核固缩,肾小管管腔扩张,上皮细胞脱离基底膜。试验表明高剂量的三聚氰胺可引起小鼠肾脏的严重损伤,造成肾小管上皮细胞变性、坏死,特征性的变化是肾小管管腔中三聚氰胺产物结晶沉积,此变化具有证病意义。     

不同群体规模下闭锁群体遗传漂变的模拟

为了研究在施行随机留种、随机交配、世代不重叠、群体间个体无迁移、整个保种过程中基因不发生突变的原位保种群体中遗传漂变的变化情况,试验采用计算机模拟方法针对不同群体规模下闭锁群体基因频率、基因型频率在50个世代中的变化进行研究。结果表明:群体规模越大,基因频率、基因型频率在世代间波动的幅度越小,因此世代间随机遗传漂变基因被固定或丢失的概率越小。     

稻田不同种植模式对蜘蛛群落的影响

2002～2004年对湖南省湘阴县藠头—水稻轮作模式和西瓜—水稻镶嵌种植模式示范基地的稻田蜘蛛进行实地调查,分析了这2种水稻种植模式中蜘蛛群落结构和季节消长动态。结果表明,西瓜—水稻模式田的物种丰富度(44)及多样性指数(4.259 54)最高;其次为藠头—水稻模式田,其物种丰富度为41、多样性指数为4.213 10;最低的是常规的双季早、晚稻田,早、晚稻的物种丰富度分别为38和32,多样性指数分别为4.110 54和3.947 63。说明采用前2种稻田种植模式,不但丰富了稻田景观元素,而且天敌蜘蛛种群数量和种类均有较显著增加。在水稻大面积种植区推广水旱轮作或间作经济作物的耕作模式,可有效地保护稻田蜘蛛等天敌,控制害虫。同时,可提高单位土地的经济效益,增加农民收入。     

杭州市抗咸二期取水工程氯度研究

潮汐河口的取水口氯度主要取决于上游下泄径流量的大小、口门潮汐强弱、下游氯度、沿江引水流量及江道地形等因素。采用概率统计方法引用条件概率概念来确定取水口的供水保证率，通过实测氯度资料分析和一维氯度数学模型研究对钱塘江河口取水段的水体氯度进行了预测分析，研究成果可为杭州市抗咸二期取水工程的选择提供决策依据，研究方法对其他强潮河口抗咸工程的研究有借鉴意义。     

Identification of resistance of Guangxi (Oryza rufipogon Griff.) to white-backed planthopper with stem evaluation method

Genetic Resources and Crop Evolution - White-backed planthopper (WBPH) is a devastating pest of rice, which significantly reduces production and causes millions of dollars in losses worldwide...     

Detection and characterization of Hepatitis E virus from commercial rabbit livers in Hebei,China

Rabbit hepatitis E virus (HEV) has been reported for years and is thought to have the potential for zoonotic transmission from rabbits to humans. As reported, HEV genotype 3 (gt3) is the most prevalent form of HEV in rabbits. To determine the prevalence of HEV in commercial rabbit livers, 176 liver samples were collected from an abattoir in Hebei Province, China. Three (1.7%) samples tested positive for RNA of HEV-ORF2 (open reading frames-2). Sequence analysis showed that the three isolates shared high identities with each other (94.08–98.85%). Further analysis showed that all the rabbit strains clustered together in the branch of HEV gt3. Further study by immunohistochemistry (IHC) assays showed that 131 (74.4%) liver samples were positive for HEV ORF2 protein. Pathological changes including cell degeneration, inflammatory cell infiltration and bile duct epithelial cell hyperplasia were observed under microscopy. These findings indicated the presence of HEV in commercial livers of rabbits. Additional studies should be conducted to investigate the infectivity of rabbit HEV (rHEV) and the potential risks of zoonotic transmission of rHEV from rabbits to human beings.     

陆地生态系统稳定性空间格局及影响机制研究综述

稳定性是生态系统保持或恢复自身结构和功能的能力,是维持生态系统服务功能的关键。近年来全球植被稳定性面临重大威胁,生态系统稳定性的研究逐步成为生态学的热点问题。本文综述了稳定性的定义、空间格局及其影响机制,指出了当前研究存在的问题,并对未来发展提出展望。目前研究发现,生态系统稳定性是一个多维结构,主要包括抵抗力、恢复力和时间稳定性三个方面。稳定性及其影响机制具有很强的空间异质性与尺度依赖性,主要表现为在站点尺度由生物多样性等生物因素控制,而在区域及全球尺度则由温度、降水、辐射等非生物因素控制。目前植被稳定性的研究中尚存在数据源噪声难以去除,量化方法未标准化等问题。未来稳定性的研究可逐步由站点等局部尺度向区域、大陆等全局尺度扩展,并形成标准化的稳定性评估方法。     

3-甲基-4-硝基酚对大鼠睾丸组织的损伤作用

为从病理学角度探讨3-甲基-4-硝基酚(PNMC)的生殖毒性,采用24只SPF雄性SD大鼠随机分为4组,染毒组分为100 mg/kg体重、10 mg/kg体重和1 mg/kg体重三组,连续5 d皮下注射,对照组皮下注射等量的溶剂(PBS+0.05%tween80)。最后一次染毒后24 h,无痛处死大鼠,称取睾丸湿重并计算其指数。将已固定的睾丸组织进行石蜡切片,采用H.E和免疫组化染色的方法观察PNMC对大鼠睾丸的病理损伤及其对凋亡相关蛋白Bcl-2和Bax表达的影响。结果显示各个染毒组与对照组相比较,睾丸大体湿重和睾丸指数明显下降(P0.05或P0.01);H.E染色结果显示各试验组睾丸曲细精管生精细胞均有不同程度的空泡变性兼或坏死;免疫组织化学染色观察发现:各实验组睾丸中Bax蛋白表达量显著高于对照组(P0.01),而Bc1-2蛋白表达量却明显低于对照组(P0.01),Bc1-2/Bax也显著低于对照组(P0.01)。研究结果表明,PNMC不仅可引起雄性大鼠睾丸曲细精管生精细胞变性、坏死,还可促进生殖细胞的大量凋亡。     

Induction ofApoptosis in the ImmatureMouse Testes by aMixture ofMelamine and CyanuricAcid

The toxicity of melamine has attracted much attention since the recent outbreaks of renal injury in pets and infants. Previous studies indicated that melamine by itself had low toxicity, whereas a mixture of melamine and cyanuric acid (M+CA) could cause serious renal damage. At present, most researches on the toxicity of M+CA are focused on the kidney. However, little is known about the adverse effects of this mixture on the reproductive system. In the present study, the toxicity of M+CA to testes was investigated. Immature male mice were orally dosed with 0, 0.6, 3, and 15 mg kg-1 d-1 of a 1:1 M+CA for 28 d. Pathological changes occurred in germ cells, such as loose arrangement, reduced numbers and karyopyknosis, indicating that this mixture was toxic to spermatogenesis. Compared with the control group, the TUNELpositive germ cells increased significantly and the ratio of Bcl-2 to Bax, total antioxidant capacity and superoxide dismutase activity decreased significantly in the 3 and 15 mg kg-1 d-1 M+CA treated group, while the activities of caspase-3, caspase- 8 and caspase-9 remained unchanged. The results suggest that M+CA can induce apoptosis in the mice testes. The downregulation of Bcl-2/Bax and oxidative stress may play a pivotal role in the induction of apoptosis by M+CA in mice testes.