东疆沙蜥和密点麻蜥的食性研究

本文对东疆沙蜥和密点麻蜥的食性特征进行了调查研究。结果表明：（１） 这两种蜥蜴的食物组成是小昆虫,主要是鞘翅目、膜翅目和半翅目等对人类有害的昆虫。（２） 食物的充塞度和活动个体数在春季有一个高峰,而在夏季有两个高峰。（３）在食物成分上有季节性变化,在春季主要猎食象鼻虫而夏季主要猎食蚜虫。（４） 它们的有益系数大于其它的两栖类和爬行类动物。     

Biotic affinities of rocky reef fishes,invertebrates and macroalgae in different zones of the Port Davey marine protected area,south‐western Tasmania

• 1. Assemblages of fishes, invertebrates, and macroalgae showed strong and predictable distributional patterns within the newly declared Port Davey marine protected area (MPA) in south‐western Tasmania. Biotic assemblages in the eastern estuarine section of the MPA within Bathurst Channel were extremely anomalous, both in relation to biota elsewhere in the Port Davey region and also to those present along the wider Tasmanian and Australian coasts. Much of this variation was due to the phenomenon of deepwater emergence, with species in 5 m water depth in eastern Bathurst Channel possessing a mean maximum recorded depth of 200 m, compared with<80 m for the same metric when calculated for sites studied elsewhere around Australia. Deepwater emergence in Bathurst Channel was particularly notable for sessile organisms, although also evident among fishes and mobile macro‐invertebrates.
• 2. Quantitative baseline surveys of reef‐associated species were undertaken at sites interspersed among MPA management zone types and biotic community types, thereby providing an appropriate benchmark for assessing ecological changes in different management zones within the Port Davey region through the long term. Distinctive biota present in eastern and western Bathurst Channel, and eastern Port Davey, are well protected within ‘no‐take’ sanctuary zones; however, a bias in location of sanctuary zones towards areas with little fishery resources resulted in less protection for the western Port Davey biota, which also extends along the open coast. Although the lack of high level protection for sites with fishery resources detracts from conservation goals, the Port Davey MPA nevertheless represents a major advance in environmental protection because the ecologically unique, fully protected locations are a necessary inclusion within any comprehensive Australian MPA network. Copyright © 2009 John Wiley & Sons, Ltd.

     

Optimization of light/dark cycle in an extended photoperiod-based speed breeding protocol for grain legumes

The use of high-performing varieties could contribute to increase food legume production and meet the population demand. However, the long process of conventional breeding is a serious limitation that needs further acceleration of genetic improvement. Speed breeding based on extended photoperiod is one of the techniques that allows rapid generation turnover by accelerating the plant life cycle. The present study focused on optimizing the duration of extended photoperiod for lentil, chickpea and faba bean in a growth chamber with light-emitting diode (LED) light sources. Significant differences in growth rate, biomass production, phenology, physiology, plant injury and yield components were observed depending on light phase durations (22, 18 and 14 h). Twenty-two hours of light resulted in earlier flowering and maturity, but higher stress symptoms than the other two light treatments. However, vegetative development was almost normal with limited stress under 14 h of light, but late flowering and maturity. Interestingly, good plant establishment with limited stress and shorter vegetative cycle was observed under 18 h of light. Therefore, a photoperiod of 18 h of light/6 h of darkness could be advised for a rapid breeding protocol.     

ECONOMIC RISK ASSESSMENT OF A SEMI-INTENSIVE SHRIMP FARM IN SINALOA,MEXICO

In Mexico shrimp farming is the most important aquaculture activity. However, its sustainable development has been threatened in recent years by the economic risk associated with low yields caused by outbreaks of viral diseases. A stochastic bioeconomic model was developed to analyze the economics of farm management adjustments as a response to disease risks, using pond-level data from a farm operating in the State of Sinaloa, Mexico, during the period 2001–2005. The data base analyzed included different combinations of stocking density (in the range 6–30 PL/m²) and culture time (from 12 to 31 weeks), which allows for wider application of the simulation results, even at the industry level. Results from this study indicate that operating costs would increase by 33% if the farmer would choose to market product directly. Scenarios with lower stocking densities and intermediate culture times generated the highest probabilities 6–9 PL/m² 16–19 weeks (76%/100%/70%), and 10–14 PL/m² 20–24 weeks (72%/99%) of achieving superior economic performance, as demonstrated by achieving the target reference point of 35% operating profit margin ratio. The study reinforces the value of the current trends in Sinaloa to reduce stocking density as a good management practice to decrease the impact of diseases. This study also provides important additional knowledge on the specific economic results and risks associated with the combination of these two management variables at different levels.     

甘蓝型油菜脂肪酸碳链延长酶BnaA.FAE1与BnaC.FAE1的底物特异性分析

为提供信息改良油料种子脂肪酸,研究脂肪酸碳链延长酶1（FAE1）的底物特异性,将甘蓝型油菜A、C基因组的BnaA.FAE1和BnaC.FAE1分别在亚麻荠种子中表达。其转基因种子中山嵛酸与芥酸含量的比值（C22:0/C22:1）分别为0.18和0.88,表明BnaA.FAE1对单不饱和脂肪酸亲和力较高,而BnaC.FAE1则对饱和脂肪酸亲和力较高,这种差异在各转基因世代表现稳定。通过分析T3转基因家系种子中酰基辅酶A（Acyl-CoAs）的组成,进一步证明了上述结论。但是在拟南芥中分别异源表达上述基因,并没有观察到类似的底物特异性差异。在甘蓝型油菜祖先种,白菜型油菜和甘蓝种子中调查其C22:0/C22:1比值,同样未发现其FAE1底物特异性存在差异。综上认为BnaA.FAE1和BnaC.FAE1在亚麻荠中存在底物特异性。     

Peanut and Amaranthus leucocarpus lectins discriminate between memory and naive/quiescent porcine lymphocytes

Lectins are relevant tools to isolate and characterize different cellular sub-populations. In this work, we used the lectins Arachis hypogaea (Peanut agglutinin, PNA) and Amaranthus leucocarpus (ALL), specific for Galss1, 3GalNAc, to characterize naive and memory lymphocytes from pigs, experimentally infected with the porcine rubulavirus (RvP). Our results showed that both lectins recognized preferentially lymphocytes with the CD4(+)CD8(+) phenotype (P<0.05). The phenotypic analysis of the cells recognized by these lectins indicated that PNA(+) lymphocytes showed higher rate of the CD29 antigen (PNA(+)CD29(high)) than ALL(+) (ALL(+)CD29(low)). The number of PNA(+)CD29(high) lymphocytes increased after 8 weeks of experimental infection with RvP, and most of the ALL(+)CD29(low) cells became CD29(middle). PNA(+) lymphocytes isolated from infected pigs proliferated after stimulation with the RvP, whereas ALL(+) cells did not. In vitro assays indicated that the ALL(+) cells from previously infected pigs diminished from 7.5 +/- 2 to 0.5 +/- 0.3% after RvP stimulation; whereas PNA(+) cells increased from 4 +/- 1 to 42 +/- 2%, whereas no modification in ALL(+) or PNA(+) cellular population was identified in lymphocytes from naive animals after RvP stimulation. Our results suggest that the cellular distribution/organization of the O-glycosydically linked glycans on lymphocytes may correlate with biological functions, and that PNA could be a tool to isolate specifically porcine memory T cell subsets, whereas ALL could be useful to isolate naive/quiescent T lymphocytes.     

A/E大肠杆菌疫苗动物模型的建立

致病性和出血性大肠杆菌 (代表株 EPEC E2 34 8和 EHEC O15 7)是婴幼儿腹泻、出血性结肠炎和尿路感染综合征 (尿毒症 )的主要病原菌 ,它们同属于粘附脱落 (Attaching/ Effacing,A/ E)大肠杆菌群 ,具有许多共同的毒力基因 ,定位于致病岛 L EE(the locus of enterocyte effacement)上。本试验主要就 A/ E大肠杆菌致病岛 L EE的 2个主要调节基因 lux和 ler基因对细菌致病性和免疫原性的影响进行了研究。所使用的始发菌株为兔致病性大肠杆菌 RDEC- 1,根据同源重组的原理 ,利用自杀性载体 p CVD44 2技术 ,敲除了位于染色体上的 lux和 ler基因 ,构建了 lux和 ler基因缺失突变株 ,研究了这 2个基因对细菌生长、毒力因子表达的调控作用以及基因缺失突变株的致病性和免疫保护作用。家兔实验研究表明 ,lux基因缺失突变株仍然残存着部分致病作用 ,不足以成为理想的致弱疫苗 ;而 ler基因缺失突变株安全性好 ,具有良好的免疫保护作用 ,是理想的家兔致弱疫苗候选株。这些研究资料为人 A/ E大肠杆菌疫苗 ,尤其是 EHEC O15 7疫苗的研制指明了方向 ,并提供了技术路线。     

Effect of three natural phytochemicals supplementation on growth performance,testosterone level and feed utilization of Nile tilapia (Oreochromis niloticus)

An 84‐day feeding experiment was conducted to determine the effects of dietary ginseng extract (GE), tribulus extract (TE) and date palm pollen grains (DPPG) on growth, testosterone level and nutrient utilization of Nile tilapia, Oreochromis niloticus, fingerlings. Seven experimental treatments were conducted in three replicates: control fed basal diets without any supplementations, GE_0.2 (supplemented with 0.2 g GE/kg diet), GE_0.4 (supplemented with 0.4 g GE/kg diet), TE_0.6 (supplemented with 0.6 g TE/kg diet), TE_1.2 (supplemented with 1.2 g TE/kg diet), DPPG₃ (supplemented with 3 g DPPG/kg diet) and DPPG₆ (supplemented with 6 g DPPG/kg diet). The results indicated that all dietary phytochemicals significantly increased growth compared to the control. Plasma testosterone levels were improved by 86.27%, 64.58%, 57.35% and 24.58% with TE_1.2, GE_0.4, TE_0.6 and DPPG₆, respectively, more than the control. The relationship between testosterone and final body weight showed a significant simple linear regression with a positive correlation. The nutrient utilization imprxoved with higher doses of phytochemical supplementations. Moreover, protein content increased and ether extract decreased with phytochemical supplementation. The present results concluded that higher doses of GE, TE and DPPG could be used as growth promoters and testosterone boosters for Nile tilapia fingerlings.     

Identification of bacterial agents causing mortality in postlarvae of giant freshwater prawn (Macrobrachium rosenbergii) in south‐west coastal districts of Bangladesh

Following an incidence of freshwater prawn Macrobrachium rosenbergii postlarvae (PL) mortality in hatcheries in summer 2012, samples from dead PL, rearing water and prawn feed from two south‐west coastal districts of Bangladesh were collected to isolate, identify and characterize the agents causing PL mortality. Antibiogram profile of sixteen randomly selected bacteria, isolated from dead PL, that grew on TCBS, to 20 different antibiotics belonging to 12 major groups revealed that the drug resistance pattern varied from moderate (56% to the drugs: ciprofloxacin, cefotaxime, nitrofurantoin, kanamycin) to complete (to penicillin, ceftazidime and oxacillin) level. To identify the isolates, amplified rDNA restriction analysis (ARDRA) classified them in to four groups, and RAPD (randomly amplified polymorphic DNA) typing yielded nine different types of isolates within these four ARDRA groups. The 16S rDNA gene sequences identified that the groups were genotypically diverse belonging to the bacterial species: Enterobacter cloacae, Klebsiella pneumoniae, Exiguobacterium profundum and Enterococcus casseliflavus, respectively, that all demonstrated their killing potential to PLs in a simulated environment. The study therefore identified four different bacterial pathogens, one of which, Exiguobacterium profundum is reported for the first here in Bangladesh, that demand special consideration for disease management strategy.