鸡传染性支气管炎病毒华南分离株核蛋白基因的序列测定及同源性分析

根据国外已发表的鸡传染性支气管炎病毒（ Ｉ Ｂ Ｖ）核蛋白基因序列,设计并合成 １ 对引物。应用这对引物,以 Ｒ Ｔ Ｐ Ｃ Ｒ 特异性扩增出华南分离株（ Ｈ Ｎ 株）的核蛋白基因,基因产物大小为 １５ ｋｂ , 与设计相符。对 Ｈ Ｎ 株部分核蛋白基因进行序列测定,并与标准毒株 Ｈ５２、 Ｍ ４１、 Ｂｅａｕ 和 Ｇｒａｙ 的核蛋白基因进行同源性比较,结果表明, Ｈ Ｎ 株与 Ｈ５２、 Ｍ ４１、 Ｂｅａｕ 和 Ｇｒａｙ 株的核酸同源性分别为 ８５％ 、８４％ ８４％ 和 ８６％ 。由此可以看出, Ｈ Ｎ 株与标准毒株在核蛋白基因上存在一定的差异。     

Estimation of seed weight, oil content and fatty acid composition in intact single seeds of rapeseed ( Brassica napus} L.) by near-infrared reflectance spectroscopy

The potential of near-infrared reflectance spectroscopy (NIRS) for the simultaneous analysis of seed weight, total oil content and its fatty acid composition in intact single seeds of rapeseed was studied. A calibration set of 530 single seeds was analysed by both NIRS and gas-liquid chromatography (GLC) and calibration equations for the major fatty acids were developed. External validation with a set of 75 seeds demonstrated a close relationship between NIRS and GLC data for oleic (r = 0.92) and erucic acid (r = 0.94), but not for linoleic (r = 0.75) and linolenic acid (r = 0.73). Calibration equations for seed weight and oil content were developed from a calibration set of 125 seeds. A gravimetric determination was used as reference method for oil content. External validation revealed a coefficient of correlation between NIRS and reference methods of 0.92 for both traits. The performance of the calibration equations for oleic and erucic acid was further studied by analysing two segregating F2 seed populations not represented in the calibration set. The results demonstrated that a reliable selection for both fatty acids in segregating populations can be made by using NIRS. We concluded that a reliable estimation of seed weight, oil content, oleic acid and erucic acid content in intact, single seeds of rapeseed is possible by using NIRS technique. This revised version was published online in July 2006 with corrections to the Cover Date.     

外源核苷酸对斑点叉尾(鱼回)生长及肠道组织发育的影响

以斑点叉尾(鱼回)幼鱼为试验对象,研究不同水平外源核苷酸对其生长和肠道发育的影响.在基础饲料中分别添加0.0%(对照组)、0.02%、0.05%和0.1%的外源核苷酸.结果表明,在斑点叉尾(鱼回)幼鱼日粮中添加外源核苷酸,促生长作用不显著(P>0.05),但可显著促进肠道组织的发育(P<0.05).     

ONPG单管定量检测法与国标法在检测海水中大肠菌群的比较研究

本实验室根据ONPG显色技术原理建立了大肠菌群单管定量检测技术,即在此基础上利用ONPG单管定量检测方法和国标法对实验室制备的标准菌的菌悬液和水样进行检测,对2种方法的检测结果进行比对.研究结果显示:两种方法对菌悬液、水样的检测结果无统计学差异,ONPG单管定量检测方法检测数据的准确性、精确性和重现性都高于国标法;ON...     

外源核苷酸对水产动物营养生理作用的研究进展

核苷酸(Nucleotide,NT)是细胞的主要组分,又是构成DNA和RNA的单体,具有调节生物体内能量代谢、参与遗传信息编码、传递细胞信号等重要的生理和生化功能[1]。由于动物机体能合成各种核苷酸,而且又没有特异的缺乏症,因而长期     

Postmortem Metabolic,Physicochemical, and Lipid Composition Changes in Litopenaeus vannamei in Response to Harvest Procedures

Ante-mortem stress is recognized as one of the factors that could reduce shelf life in fish, although this topic has been scarcely addressed in crustaceans, particularly in cultivated penaeid shrimp where common harvest practices involves stressful conditions such as chasing, emersion, and confinement. This study analyzes indices of freshness in shrimp in response to such practices before storage in ice for six days. During ice storage, several indicators follow the typical postmortem pattern, although most of them (hypoxanthine, change in pH, and color) did not reach critical levels at day 6. Adenosine-5’-triphosphate (ATP) and degradation products (adenosine monophosphate, AMP, and inosine monophosphate, IMP), as well as several indicators of freshness (pH, expressible water, hardness, color, and the overall fatty acid composition) were not significantly affected by harvest. Other variables such as lower springiness, higher hypoxanthine, lipid hydroperoxides, and 20:4n-6/20:5n-3 ratio were observed in shrimp subjected to common harvest practices. However, under the current conditions of harvesting, these effects were marginal and probably do not substantially affect meat quality for human consumption, but care should be taken at higher environmental temperatures (e.g. harvest in summer) and for a duration of ice-storage over 6 days.     

禽大肠杆菌O2、O78菌株外膜蛋白A基因扩增及序列分析

根据Genbank中大肠杆菌K-12外膜蛋白A基因的核苷酸序列设计引物,从禽大肠杆菌O为O2、O78及它们的融合株O2．78(Chl^rNor^r)中分别扩增得到外膜蛋白A基因(ompA),进行序列测定及分析发现3个菌株的ompA均由2276nt组成,核苷酸序列完全相同,只有一个大的开放性阅读框(ORF),长1041bp,编码由346个氨基酸组成的前外膜蛋白A(pro-OmpA),前21个氨基酸残基组成信号肽,成熟的OmpA由325个氨基酸残基组成,相对分子质量为37000．其氨基酸序列也完全相同．从基因水平上证明了禽大肠杆菌O2和O78菌株存在相同的外膜蛋白A抗原。     

瓜叶菊的离体培养与快速繁殖

为探索瓜叶菊杂合体母株优良性状的保存方法,以便快速有效地进行瓜叶菊种苗的生产,以瓜叶菊5个不同花色母株的单芽茎段为外植体进行了离体培养与快速繁殖研究．结果表明：1)不同激素组合的培养基对瓜叶菊茎段初始培养中芽诱导的影响因母株花色不同而不同,尤其在芽萌动时间和萌动数量上表现明显,其中以来自母株M1的外植体在含有0．1mg／LNAA 2mg/LBA的A5培养基的诱导率最高,芽萌动早且数目多;2)在继代培养中,在0～2．0mg／L范;围内,随BA质量浓度的增加,瓜叶菊芽的增殖倍数增大,但当BA为3．0mg/L时,外植体茎叶随着时间推移逐渐变厚变脆,成愈伤组织状;3)C6培养基(1／2MS 0．5mg/LIBA 2％蔗糖)是瓜叶菊离体生根培养比较合适的培养基,培养到第16天时根系诱导率为100％,平均根数为18条,平均根粗为0．09cm;来自C6的试管苗移栽成活率可达95％．     

北冬虫夏草(Corayceps militaris)室内栽培技术研究

2003年从北京北冬虫夏草(Cordyceps militaris)子实体的子座部分经单孢分离出Ⅱ号菌株.2004年从北京、上海北冬虫夏草新鲜子实体中采用组织分离法分离出Ⅰ号、Ⅲ号和Ⅳ号菌株,同时收集到开封试管菌株Ⅴ号.Ⅱ号菌株在不同培养基(5,6,7号)进行瓶栽试验,并与4个菌株(Ⅰ号、Ⅲ号、Ⅳ号、Ⅴ号)在同一培养基进行瓶栽比较试验.经过50d的观察表明,Ⅱ号菌株在5号和6号培养基上所产生子实体及每瓶平均数量,平均长度,平均鲜重和干重都比在7号培养基上良好;Ⅰ号、Ⅲ号、Ⅳ号菌株在5号培养基上生的子实体无论每瓶平均数量、平均长度、平均鲜重和干重都明显比Ⅴ号菌株子实体情况优良.     

挂果对纽荷尔脐橙枝条源叶光合作用的影响

在纽荷尔脐橙果实膨大期,选取1年生双果枝、单果枝和营养枝,测定源叶净光合速率（Pn）、气孔导度（Cond）、蒸腾速率（Trmmol）等光合生理指标,探讨挂果对枝条源叶光合特性的影响。结果表明,挂果对叶片 （源） Pn、Cond、Trmmol在上午光合作用较强时间段影响显著,对Ci和Tleaf无显著影响,并且无果枝Pn高于单果枝和双果枝。挂果对果枝叶片Pn、Cond、Trmmol、Ci的日变化曲线没有影响,Pn仍然表现为典型的“双峰”曲线。