生长激素释放因子（GRF）的基因改造及化学合成

为了提高生长激素释放因子（ＧＲＦ）的体内活性,根据猪ＧＲＦ的天然序列,设计了改造后ＧＲＦ（１～３２）的基因序列（含信号肽）,两端加设ＥｃｏＲＩ、ＨｉｎｄⅢ的粘性末端,分４段由ＤＮＡ合成仪合成,每段长度分别为９５、９７、８６、１０６ＮＴ,２条链间有１５个碱基的粘端。用尿素变性ＰＡＧＥ纯化合成片段,用Ｔ４多核苷酸激酶对合成ＤＮＡ磷酸化,混合４个片段复性,然后用Ｔ４连接酶连接。提取ｐＢｌｕｓｃｒｉｐｔ质粒,用ＥｃｏＲＩ和ＨｉｎｄⅢ在Ｍｕｌｔｉｃｏｒｅｂｕｆｅｒ中酶切完全后,琼脂糖电泳,由ＧｅｎｅＥｌｕｔｅＡｇｒｏｓｅＳｐｉｎＣｏｌｕｍｓ回收酶切大片段。将该酶切片段与上述合成的ＧＲＦ基因由Ｔ４连接酶连接,并转化至氯化钙致敏的ＤＨ５α。选取重组菌落,提取质粒,用ＰＣＲ及双酶切鉴定阳性克隆。用Ｍｉｎｉｐｒｅｐ提取重组质粒,ＡＢＩ３７３自动测序仪测序。测序结果表明已克隆到合成的ＧＲＦ基因。     

数字PCR在转基因定量检测中的研究进展

数字PCR对核酸分子进行定量检测时不依赖于标准曲线和标准物质,在转基因定量检测中可直接计算出模板中外源基因的拷贝数浓度值和转基因含量。本文概述了数字PCR在转基因定量检测中的应用,将数字PCR与实时荧光定量PCR的技术参数从检测特异性、线性动态范围、准确度、灵敏度、稳健性等方面进行了对比分析,以利其在转基因生物安全管理及转基因标识制度发挥技术支撑作用。本文还阐述了影响数字PCR检测结果的因素,探讨了数字PCR结果溯源至SI单位的可能性,为数字PCR在转基因定量检测以及其它领域核酸精确定量的应用提供参考。     

Assessing fitness parameters of hybrids between weed beets and transgenic sugar beets

Herbicide resistance is a desired trait for sugar beet (Beta vulgaris L.) production because it is a low‐competitor crop that requires careful weed management. However, gene flow to weed beet (also B. vulgaris) could jeopardize the weed control strategy by causing the emergence of resistant weed beets; it could also lead to further adaptation of weed beet as a troublesome weed for other crops by selecting more competitive plants. To evaluate the hazard that such a selection process represents, apart the herbicide resistance, we investigated the morphology and reproduction of progeny of weed beets having inherited a herbicide resistance gene. First‐generation resistant weed beet exhibited traits likely counter‐selected. But such crop traits rapidly disappeared with backcrossing to weedy relatives: no biologically relevant difference was noted between resistant and susceptible near‐isogenic siblings in the various experiments. In the absence of resistance selection, our data indicate low chances for weed beet to evolve more competitive forms than present weed beet populations. However, they also suggest that there is no fitness cost limiting transgenes spread.     

Leaf Cell‐Wall Components as Influenced in the First Phase of Salt Stress in Three Maize (Zea mays L.) Hybrids Differing in Salt Resistance

The leaf cell wall (CW) chemical composition of three maize (Zea mays L.) hybrids (salt‐resistant SR 03 and SR 12, salt‐sensitive Pioneer 3906) was investigated in the first phase of salt stress (100 mm NaCl) compared with the control (1 mm NaCl) treatment to investigate whether changes in CW composition were responsible for shoot growth reduction. Salt treatment caused a strong inhibition in shoot growth with a concomitant increase in the ratio between CW dry mass (DM) and shoot fresh mass (FM) and a decrease in CW cellulose concentrations in all hybrids. NaCl caused a large increase in the concentrations of total and non‐methylated uronic acid (UA) in salt‐sensitive Pioneer 3906 and salt‐resistant SR 12. The onset of the accumulation of non‐methylated UA was delayed in SR 12, which indicates that this may be one reason for the better growth performance of this hybrid under salt stress compared with Pioneer 3906. It is concluded that a low accumulation of non‐methylated UA in leaf CW may, among other mechanisms, contribute to salt resistance in the first phase of salt stress.     

Precision and Application of Electronic Nose for Freshness Monitoring of Whole Redfish (Sebastes marinus) Stored in Ice and Modified Atmosphere Bulk Storage

Abstract

An electronic nose with electrochemical gas sensors (CO, NH₃, SO₂ and H₂S) was used as a rapid technique to monitor changes in the headspace of whole ungutted redfish (Sebastes marinus) stored in ice and under various conditions of modified atmosphere (MA) bulk storage (CO₂/N₂:60/40). The precision of the electronic nose measurements was determined using standard compounds (ethanol, trimethylamine, acetal-dehyde and dimethyldisulfide). The response of the CO sensor, suggesting the formation of alcohols and carbonyls, increased with time for both aerobic and MA storage and correlated well with sensory analysis using the Quality Index Method. Slower spoilage rate reflected by lower intensities of sensors' responses, lower microbial counts and less TMA production were observed in MA-stored redfish compared with aerobic storage in ice.     

大豆遗传转化方法及再生体系研究进展

转基因技术作为现代生物技术之一,在基因功能研究和转基因育种方面取得重要进展。大豆基因组测序之后,大豆功能基因组学发展迅速,挖掘控制重要性状的基因用于转基因育种受到广泛关注。随着转基因大豆新品种培育重大专项的实施,我国建立了基因克隆、遗传转化、功能研究、转基因品系安全评价等转基因育种研究技术体系和监管体系。其中,转基因大豆遗传转化技术体系的研究取得了较快的进展,主要集中在高效、稳定遗传转化再生体系的建立和优化,大豆遗传转化方法的探索和优化等方面。对大豆遗传转化体系、转化方法和转化效率等因素进行阐述,可为大豆基因功能研究和转基因新品种培育相关研究提供参考。     

论陆羽《茶经》中的茶审美观

自1994年首个转基因植物产品番茄商业化以来，转基因技术、研发、产业等均取得了飞速进展，本文分析了转基因食品目前的研发、获批情况，种植推广、安全性评价等状况及我国转基因食品获批、消费、管理状况，提出了在目前转基因食品安全争论和贸易壁垒形势下的对策和建议。     

The Control of Phytophthora cinnamomi Rands in a South African Forest Nursery

Tests of several fumigants which control Phytophthora cinnamomi Rands under field and glasshouse conditions are reported. The soil fumigant basamid is the cheapest effective treatment available, at present. The implications of failure to control Phytophthora cinnamomi for forestry, agriculture and the indigenous flora are briefly discussed.     

Chemical composition of traditionally and lesser used wood species from Mozambique

Abstract

The main objective of this study was to determine the chemical composition of some lesser used Mozambican native wood species, such as Acacia nigrescens Oliv., Icuria dunensis Wieringa, Pseudolachnostylis maprounaefolia Pax and Sterculia appendiculata K. Schum. Another aim was to compare these species with traditionally used species, namely, Afzelia quanzensis Welwn, Milletia stuhlmannii Taub, Pericopsis angolensis Meeuwen and Pterocarpus angolensis DC. Wood samples for analysis were taken from sapwood, outer and inner heartwood. All chemical analyses were performed according to standard methods. The contents of carbohydrates, extractives and ash were in ranges considered normal for tropical species. The contents of lignin and minerals were unexpectedly high in Pseudolachnostylis (ntholo), reaching 37.51% and 2.2% (wt% extractive-free) on a dry basis, respectively. Based on the determined chemical features, it was concluded that Acacia and Pseudolachnostylis were similar to well-known species, whereas Icuria and Sterculia differed from the known species.