热带人工草地群落结构研究初探

研究4年生热带人工草地放牧与不放牧对群落结构的影响,结果表明:以热研2号柱花草和珊状臂形草为优势草种的人工草地,其中对照区(不放牧)干草产量8096kg/hm²,极显著高于天然草地116.04%,放牧区6324.5kg/hm²,显著高于天然草地68.77%;其产草量呈动态变化,以10月最高;植被群落呈垂直空间层状分布,产草量多集中在11～40cm草层;在放牧区热研2号柱花草的频度和产草量减少,珊状臂形草和有钩柱花草增加,草种分布均匀,结构合理,向进展方向演替。     

养殖银鲳虹彩病毒感染的组织病理学分析及分子检测

2018年7月,宁波象山某养殖场内银鲳出现集中死亡现象,累积死亡率高达80%以上,为探究此次疾病暴发的原因,本研究通过对患病银鲳进行组织病理学分析、透射电镜观察、病原的分子生物学检测及分析来对其病原进行鉴定,以便制定合理的防控措施。患病银鲳临床表现为厌食、身体失衡、脾脏肿大、肝脏颜色异常等病征。组织病理学观察发现,患病银鲳肝脏、脾脏和肾脏均出现直径10～15μm、细胞质嗜碱性的肿大细胞。进一步的透射电镜观察则在脾脏、肾脏等组织细胞内发现了病毒包涵体结构以及大量的病毒粒子,直径为140～160 nm。通过虹彩病毒特异性PCR检测发现,患病组织样品为虹彩病毒阳性。此外,通过病毒主要衣壳蛋白基因(MCP)序列分析,发现银鲳源病毒与大黄鱼虹彩病毒(GenBank登录号:AY779031.1)MCP同源性最高为99.76%,认为此分离病毒属于虹彩病毒科、肿大细胞病毒属、真鲷虹彩病毒(Red sea bream iridovirus, RSIV)类群。本实验首次报道了全人工养殖环境下银鲳感染虹彩病毒的病例,该研究将为养殖银鲳虹彩病毒病的诊断和防治提供重要的参考依据。     

海水和淡水养殖凡纳滨对虾呈味物质的比较分析

对使用同种饲料喂养的海水和淡水养殖凡纳滨对虾(Litopenaeusvannamei)进行了感官评价、一般成分和呈味物质分析。海水养殖对虾感官评价总体得分高于淡水养殖对虾,海水养殖对虾在鲜味、甜味上优于淡水养殖对虾,而淡水养殖对虾带有明显的土腥味(P<0.01)。海水养殖对虾的灰分高于淡水养殖对虾,粗蛋白、水分及有机酸含量两类对虾差异不大。通过分析氨基酸、核苷酸、甜菜碱和有机酸等呈味物质,发现主要是谷氨酸、AMP、IMP、甜菜碱这几种物质对两类对虾的口味差异起着重要作用,其他成分作用不明显。     

盐碱土区水稻旱育苗磷肥施用技术研究

试验以氮,钾肥做底肥一次施入,研究磷酸二铵施用量和施用时期对秧苗素质的影响。试验结果表明,在１ｍ６２苗床２５ｋｇ风干河淤土中一次性施入尿素２６ｇ,硫酸钾２４ｇ做底肥,于稻苗一叶期施用磷酸二铵,秧苗综合素质好,磷酸二铵用量在１３／３９ｇ／ｍ＾２之间秧苗素质基本一致。     

季铵盐类对对虾毒性和对弧菌杀灭效果的研究

国外及我国台湾等地普遍应用季铵盐类（ＢＫＣ）防治虾病,作者以国内生产的ＢＫＣ对斑节对虾Ｐｅｎａｅｕｓｍｏｎｏｄｏｎ、新对虾Ｍｅｔａｐｅｎａｅｕｓｓｐ．幼体及成虾的毒性和对弧菌的杀灭效果进行检测,以解决对虾养殖中药物的应用技术问题。实验表明,ＢＫＣ对斑节对虾各期幼体及成体的毒性存在着明显的差异,无节幼体对ＢＫＣ的敏感性特别高;弧菌及细菌对ＢＫＣ并不十分敏感,在２～３ｍｇ．Ｌ－１的浓度条件下才能杀灭水中７５％～９０％的弧菌。对成虾的细菌病,建议使用的ＢＫＣ浓度为０．５～１ｍｇ．Ｌ－１。     

苦丁茶组培苗的生根与移栽

正交试验表明 ,苦丁茶组培苗基内生根的主要影响因子是生长素 NAA,其次是培养基中大量元素的含量 ,其合适的生根配方是 1/ 4 MS+2 %蔗糖 +NAA 0 .1～ 0 .2 mg· L-1。加入活性炭反而抵消了 MAA的作用。蛭石是良好的扦插基质 ,用高浓度 NAA短时间处理切口 ,生根又快又好。苦丁茶生根苗移栽成活的关键是杀菌防病并遮阴保湿。以健壮无根苗直接一步移栽入土更简化了快繁工艺。     

Anti-Allergic Effect of 3,4-Dihydroxybenzaldehyde Isolated from Polysiphonia morrowii in IgE/BSA-Stimulated Mast Cells and a Passive Cutaneous Anaphylaxis Mouse Model

In this study, we investigated the anti-allergic effects of 3,4-dihydroxybenzaldehyde (DHB) isolated from the marine red alga, Polysiphonia morrowii, in mouse bone-marrow-derived cultured mast cells (BMCMCs) and passive cutaneous anaphylaxis (PCA) in anti-dinitrophenyl (DNP) immunoglobulin E (IgE)-sensitized mice. DHB inhibited IgE/bovine serum albumin (BSA)-induced BMCMCs degranulation by reducing the release of β-hexosaminidase without inducing cytotoxicity. Further, DHB dose-dependently decreased the IgE binding and high-affinity IgE receptor (FcεRI) expression and FcεRI-IgE binding on the surface of BMCMCs. Moreover, DHB suppressed the secretion and/or the expression of the allergic cytokines, interleukin (IL)-4, IL-5, IL-6, IL-13, and tumor necrosis factor (TNF)-α, and the chemokine, thymus activation-regulated chemokine (TARC), by regulating the phosphorylation of IκBα and the translocation of cytoplasmic NF-κB into the nucleus. Furthermore, DHB attenuated the passive cutaneous anaphylactic (PCA) reaction reducing the exuded Evans blue amount in the mouse ear stimulated by IgE/BSA. These results suggest that DHB is a potential therapeutic candidate for the prevention and treatment of type I allergic disorders.     

Toxicity of cultured puffer fish and seasonal variations in China

To confirm the toxicity or the tetrodotoxin (TTX) content of cultured puffer fish in China, 565 specimens of cultured puffer fish (Takifugu rubripes, Takifugu fasciatus or Takifugu obscurus, Takifugu flavidus and Takifugu bimaculatus) were collected from five provinces from November 2007 to November 2008. The toxicity of the skin, muscle, liver and testis/ovary was examined using methods based on a mouse assay for TTX. The results indicated that the skin, muscle, liver and testis of specimens were ‘non‐toxic’ in both of the mouse assays [<10 mouse unit (MU) g^?1 or 2.2 μg g^?1] from the viewpoint of food hygiene. However, TTX was detected from an ovary sample of the cultured T. rubripes collected from the Shandong province in March 2008, which was 125.43 MU g^?1 tissue. The average TTX contents in the muscle, liver and skin of T. rubripes from Hebei and Shandong provinces were the highest in May or July (1.31, 0.90 and 0.62 MU g^?1, respectively, in Hebei, and 1.57, 0.32 and 0.16 MU g^?1, respectively, in Shandong) and the lowest in January (<0.1 MU g^?1 or 0.02 μg g^?1). Thus, non‐toxic cultured puffer fish could be produced successfully in mainland China.     

圈养野生动物疾病与气象因子的相关性及其预测

对1975～1998年间的北京动物园野生动物发病率进行统计,分析了兽类、禽类及其各系统发病率的月份、季度、年际变化特点,并与同期北京地区的气温等13项气象资料进行结合分析,讨论了每季度发病率与同期、前期气象因子的关系,在此基础上利用逐步回归分析,建立各月预报方程,经F检验,效果良好。