根癌农杆菌介导豇豆胰蛋白酶抑制剂基因转入苹果主栽品种

研究建立起一套简单、高效的苹果遗传转化系统。利用根癌农杆菌介导的叶圆片转化法将高效启动的豇豆胰蛋白抑制剂基因（ＣｐＴｌ）转入富士、齐纳金、王林、嘎拉等苹果主栽品种中,经卡那霉素抗性、ＰＣＲ、点杂交、Ｓｏｕｔｈｅｍ杂交检测证明了４个品种均获得转化再生植株,现已移栽成活。     

Interactions between earthworms, trees, soil nutrition and metal mobility in amended Pb/Zn mine tailings from Guangdong, China

This paper reports research that attempts to rehabilitate toxic Pb/Zn mine tailings, in Guangdong, China, to achieve a healthy functional soil that supports sustainable vegetation. We studied the effects of the earthworm Pheretima guillelmi on the growth of a woody legume Leucaena leucocephala on Pb/Zn mine tailings diluted with varying amounts of mineral soil in pot experiments. L. leucocephala grew successfully on tailings with a 25% (w/w) soil amendment, but P. guillelmi only survived and actively burrowed with a 50% soil amendment. The presence of earthworms improved the yield of plants by 10-30%. Whilst earthworms marginally increased available N and P in soil, they increased uptake of phosphorus (by about 10%) to above-ground plant tissues. Six-month-old plants were more sensitive than 10-month plants to metal stress. P. guillelmi increased bioavailable metal concentrations in the amended spoils, accompanied by a direct increase of metal uptake by the plants. Increased metal uptake by plants was largely due to the higher dry matter production stimulated by earthworm activity, but this increased the rate of metal uptake into plants from spoil by at least 16% and as much as 53%. These results demonstrate that we should broaden the ecological context of phytoremediation by considering the plant-soil-animal interactions that influence metal mobility.     

Characterization of antioxidants present in bitter tea (Ligustrum pedunculare)

The present study examined the antioxidants present in bitter tea (Ligustrum pedunculare). It was found that the crude glycoside fraction strongly protected human low-density lipoprotein (LDL) from oxidation. Further column chromatography led to purification of eight phenylethanoid or monoterpene glycosides: lipedoside A-I, lipedoside A-II, lipedoside B-I, lipedoside B-III, lipedoside B-V, lipedoside B-VI, osmanthuside B, and anatolioside. It was found that lipedoside A-I, lipedoside A-II, lipedoside B-V, and lipedoside B-VI were protective, whereas the other four compounds did not protect human LDL from Cu(2+)-medicated oxidation. Lipedoside A-I, lipedoside A-II, lipedoside B-V, and lipedoside B-VI also had a scavenging effect on 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH), comparable to that of alpha-tocopherol. The inhibitory effect of these four phenylethanoid or monoterpene glycosides on oxidation of human LDL and alpha-tocopherol was dose-dependent at concentrations of 5-40 microM. The present results demonstrate that bitter tea as a beverage contains effective antioxidants that may have benefits similar to those of green tea in terms of antioxidant activity.     

Incidence and effects of West Nile virus infection in vaccinated and unvaccinated horses in California

A prospective cohort study was used to estimate the incidence of West Nile virus (WNV) infection in a group of unvaccinated horses (n = 37) in California and compare the effects of natural WNV infection in these unvaccinated horses to a group of co-mingled vaccinated horses (n = 155). Horses initially were vaccinated with either inactivated whole virus (n = 87) or canarypox recombinant (n = 68) WNV vaccines during 2003 or 2004, prior to emergence of WNV in the region. Unvaccinated horses were serologically tested for antibodies to WNV by microsphere immunoassay incorporating recombinant WNV E protein (rE MIA) in December 2003, December 2004, and every two months thereafter until November 2005. Clinical neurologic disease attributable to WNV infection (West Nile disease (WND)) developed in 2 (5.4%) of 37 unvaccinated horses and in 0 of 155 vaccinated horses. One affected horse died. Twenty one (67.7%) of 31 unvaccinated horses that were seronegative to WNV in December, 2004 seroconverted to WNV before the end of the study in November, 2005. Findings from the study indicate that currently-available commercial vaccines are effective in preventing WND and their use is financially justified because clinical disease only occurred in unvaccinated horses and the mean cost of each clinical case of WND was approximately 45 times the cost of a 2-dose WNV vaccination program.     

Rapid testing methods for food contaminants and toxicants

Food safety is one of the major concerns in every country regardless of the economic and social development. The frequent occurrence of food scandals in the world has led the Chinese government to implement several strategies to fortify the food supply system to a high food safety standard. This relies heavily on laboratory testing services but conventional methods for detection of food contaminants and toxicants are limited by sophisticated sample preparation procedures,long analysis time,large instruments and professional personnel to meet the increasing demands. In this review,we have incorporated most of the current and potential rapid detection methods for many notorious food contaminants and toxicants including microbial agents,toxic ions,pesticides,veterinary drugs and preservatives,as well as detection of genetically modified food genes and adulterated edible oil. Development of rapid,accurate,easy-to-use and affordable testing methods could urge food handlers and the public to actively screen for food contaminants and toxicants instead of passively relying on monitoring by the government examination facility. This review also provides several recommendations including how to encourage the public to engage in the food safety management system and provide optimal education and financial assistance that may improve the current Chinese food safety control system.     

The composite genome of the legume symbiont Sinorhizobium meliloti

The scarcity of usable nitrogen frequently limits plant growth. A tight metabolic association with rhizobial bacteria allows legumes to obtain nitrogen compounds by bacterial reduction of dinitrogen (N2) to ammonium (NH4+). We present here the annotated DNA sequence of the alpha-proteobacterium Sinorhizobium meliloti, the symbiont of alfalfa. The tripartite 6.7-megabase (Mb) genome comprises a 3.65-Mb chromosome, and 1.35-Mb pSymA and 1.68-Mb pSymB megaplasmids. Genome sequence analysis indicates that all three elements contribute, in varying degrees, to symbiosis and reveals how this genome may have emerged during evolution. The genome sequence will be useful in understanding the dynamics of interkingdom associations and of life in soil environments.     

MARINE FISH PRODUCTION AND MARKETING FOR A CHINESE FOOD MARKET: A TRANSACTION COST PERSPECTIVE

ABSTRACT

From a transaction cost perspective, this paper shows how the tradition of consuming marine fish by the majority of Hong Kong's Chinese citizens has shaped the means and modes of marketing seafood in Hong Kong. It is argued that consumer preferences stimulate aquaculture as a non-open access measure to bypass state fish marketing regulations. This has resulted in two outcomes. First, the transaction cost savings on metering output quantity and quality under private property have led not only to the collapse of the state monopoly on marine fish marketing, but also to the emergence of the (then new but) currently popular kind of Chinese seafood restaurant in Hong Kong. Second, consumer preferences for variety have shaped the form of coordination between the producer and the consumer. The advantage of market coordination has led to the emergence of a system of wholesaling and retailing rather than vertical integration. Issues concerning the emergence of Hong Kong as a regional live marine fish production and trading centre are discussed in terms of the contribution of local mariculture to sustainable development.