vvi-miR160s介导VvARF18应答赤霉素调控葡萄种子的发育

【目的】研究vvi-miR160家族（vvi-miR160s）及其靶基因在‘魏可’葡萄种子发育过程中的作用,探究其应答赤霉素（GA）调控葡萄果实无核的潜在机理。【方法】采用miR-RACE、生物信息学分析、RT-qPCR、RLM-RACE等方法,鉴定vvi-miR160家族成员及其靶基因,分析vvi-miR160s及其靶基因应答GA的时空表达模式及其潜在功能。【结果】花前GA处理强烈抑制‘魏可’葡萄胚珠及种子发育,高效诱导其无核,且无核率达99.8%。克隆鉴定了VvMIR160s前体基因序列（501 bp）及成熟体序列,且它们在不同物种间具有较高的保守性;基于vvi-miR160s序列,预测到靶基因VvARF18,利用RLM-RACE技术检测到vvi-miR160s对VvARF18的裂解位点在第10和第11位之间,裂解频度9/17,证明VvARF18是vvi-miR160s的真实靶基因。该靶基因编码683个氨基酸,在398—411位存在核定位信号,且该蛋白亚细胞定位于细胞核上。VvARF18与其他物种间序列的同源保守性较高,基因结构相似,其中VvARF18蛋白与茶、烟草、梅花等物种亲缘关系较近。VvARF18启动子中包含4种作用元件,且含有较多激素相关元件。RT-qPCR结果显示,随着葡萄果实的发育,vvi-miR160c/d/e呈现‘V’形表达趋势,在硬核种子发育期表达较低,而VvARF18表现出与前者相反的表达趋势,在硬核种子发育期呈现高表达,表明vvi-miR160c/d/e对VvARF18负调控,但vvi-miR160a/b与VvARF18表达水平却不存在明显负相关。GA处理极显著地上调了vvi-miR160a/b在葡萄硬核种子发育期的表达,同时也显著抑制了VvARF18在同时期的表达,且它们的表达水平呈负相关,表明GA处理促进了vvi-miR160a/b对VvARF18的负调控作用;相反,GA减弱了vvi-miR160c/d/e对VvARF18的负调控作用。【结论】在vvi-miR160家族中,vvi-miR160c/d/e可能介导VvARF18在葡萄种子发育的特定阶段调控种子的发育形成,而vvi-miR160a/b可能主要介导VvARF18参与调控GA诱导葡萄种子败育的过程。     

Effects of dietary supplementation of Haematococcus pluvialis powder on gonadal development,coloration and antioxidant capacity of adult male Chinese mitten crab (Eriocheir sinensis)

The green algae Haematococcus pluvialis is an important source of natural astaxanthin as feed additive. This study was conducted to investigate the effects of dietary supplementation of H. pluvialis powder on gonadal development, coloration and antioxidant capacity of adult male Chinese mitten crab Eriocheir sinensis, and four experimental diets were formulated to contain 0, 0.2%, 0.4% and 0.6% of H. pluvialis powder. There were four treatments (defined as D1~D4) in this study and each treatment had three replicates. Dietary H. pluvialis contents had no significant effects on survival, body weight gain rate and gonadal development of male E. sinensis. For colour parameters, the total carotenoids content in carapace and hepatopancreas as well as hepatopancreatic lightness (L*) and carapace redness (a*) increased significantly with increasing dietary H. pluvialis (p < 0.05). For the antioxidant indices in the serum, D4 had the lowest activities of superoxide dismutase (SOD) and peroxidase (POD), but the highest glutathione peroxidase (GSH‐Px) and lactic dehydrogenase (LDH), while the malondialdehyde (MDA) in serum and hepatopancreas decreased significantly with the rising content of dietary H. pluvialis (p < 0.05); D1 had the highest levels of SOD, POD and GSH‐Px in hepatopancreas. For the non‐specific immune indices, the highest activities of acid phosphatase (ACP) and γ‐glutamyl transpeptidase (γ‐GT) were found on the serum of D3 and D4 (p < 0.05). D1 had the highest levels of ACP and alkaline phosphatase (ALP) in hepatopancreas, while D2 and D3 had the lowest levels of ALP and ACP respectively. These results suggested the optimal dietary natural astaxanthin level was around 40 mg/kg diets.     

Natural bixin as a potential carotenoid for enhancing pigmentation and colour in goldfish (Carassius auratus)

Discovering natural carotenoids for colour enhancement and health benefits of fish is important to develop new feed formulations. We have purified natural bixin from achiote seeds and evaluated the effect of colour enhancing and pigmentation in goldfish. Varying levels of bixin‐based diets were prepared with 420 g kg^?1 of crude protein and 120 g kg^?1 of lipid content. Our results clearly showed that bixin (0.05, 0.10, 0.20 and 0.60 g kg^?1) based diets significantly (P < 0.05) enhanced the skin and fin colour at 30 and 60 days compared to diet without bixin. Interestingly, diet which contains 0.20 g kg^?1 bixin and commercial feed (with astaxanthin) had similar effect on carotenoid deposition in skin. Moreover, total carotenoid deposition in fin was higher than in skin of all bixin‐containing diets. However, 0.60 g kg^?1 bixin‐containing diet had lower specific growth rate (1.01 ± 0.01) and higher feed conversion ratio (2.05 ± 0.19) compared to the control group. The present results demonstrate that achiote bixin can be successfully used as an alternative natural carotenoid source against synthetic astaxanthin in fish feed. Our data indicate that 0.20 g kg^?1 is a suitable dietary level of bixin to ensure strong pigmentation, acceptable growth and feed utilization in goldfish.     

Effects of blue shrimp Litopenaeus stylirostris and goldlined rabbitfish Siganus lineatus in mono‐ and polyculture on production and environmental conditions

This study was conducted to compare the effects of shrimp and rabbitfish in mono‐ and polyculture stocked at high biomass on production and environmental conditions in a mesocosm system. Shrimp (14 g) and/or rabbitfish (19 g) were stocked in four treatments with different density but with the same total biomass (236 g m^?2), including shrimp monoculture (SM) (17 shrimp m^?2), shrimp–fish polyculture (SF) (11 shrimp and 4 rabbitfish m^?2), fish–shrimp polyculture (FS) (6 shrimp and 8 rabbitfish m^?2) and fish monoculture (FM) (12 rabbitfish m^?2). After 10 weeks of experiment, shrimp survival and biomass were low in the treatments where shrimp were dominant (SM, SF), while rabbitfish survival and biomass were high in all the treatments. Shrimp mortality was assumed to be related to an excess of the system carrying capacity (CC). Results suggested that CC is linked to shrimp biomass/density rather than the system eutrophication level. The ecosystem became heterotrophic as daily feed supply was beyond 7 g m^?2 per day. This threshold corresponded to the environmental CC of the semi‐intensive shrimp culture system. Under these conditions, the combination of high fish biomass and low shrimp biomass appeared as the most valuable in terms of system performances.     

有色黏虫板对柑橘木虱的监测及防治研究进展

柑橘黄龙病是柑橘生产中的重大病害,随着其在全球范围内的传播蔓延,该病已成为近年来柑橘生产和研究中普遍关注的热点。柑橘木虱(Diaphorina citri Kuwayama)是传播柑橘黄龙病菌(Candidatus Liberibacter asiaticus)的主要虫媒,对柑橘木虱种群的准确监测与有效防控是控制柑橘木虱传播黄龙病的关键所在。有色黏虫板是一种利用昆虫趋色性,对小型飞行昆虫进行监测与诱杀的重要物理防治手段。有色黏虫板同样适用于监测和诱捕柑橘木虱,但黏虫板的颜色、光源、气候条件、悬挂黏虫板的植物种类及其挥发性信息化合物成分等都会影响黏虫板对柑橘木虱的诱集效果。本文在综合国内外柑橘木虱防控技术的基础上,将近年来利用有色黏虫板,监测与防控柑橘木虱的最新进展进行综述,并对有色黏虫板的发展前景给予展望。     

Effects of stocking density on the performance of brown shrimp Farfantepenaeus californiensis co‐cultured with the green seaweed Ulva clathrata

The brown shrimp Farfantepenaeus californiensis and the seaweed Ulva clathrata, both native to north‐west Mexico, were co‐cultured in lined ponds during 18 weeks. The aim of this study was to evaluate different stocking densities (10, 20, 30, 40 and 50 per m²) in terms of shrimp yield to see if the co‐culture method results in shrimp yields suitable for commercial production. The presence of Ulva results in good water quality and allows culture of brown shrimp with low water exchange (10% weekly) and with low nitrogen and phosphorus content in discharged water. The final weight and specific growth rate (SGR) in shrimp between 10 and 30 per m² were significantly higher (12.5–12.0 g and 4.56–4.53% day⁻¹ respectively) than 40 and 50 per m² (9.1 and 8.6 g, and 4.31% and 4.26% day⁻¹ respectively). Total shrimp biomass generated in 30 or more shrimp per m² was significantly higher (2.7–3.1 t ha⁻¹) compared with 10 and 20 shrimp per m² (1.0 and 2.0 t ha⁻¹ respectively). The lowest feed conversion ratio (FCR) (0.97) was shown in the 10 shrimp per m² case, and the highest FCR was seen with 50 shrimp per m² (1.37). Shrimp survival ranged between 71% and 81%, where the highest mortality was shown in 50 shrimp per m². The results show that the co‐culture method can result in commercially interesting yields, suggesting that 30 shrimp per m² is the best stocking density for co‐culturing F. californiensis with U. clathrata, based on the shrimp performance.     

Settlement behavior of American lobster (Homarus americanus): effect of female origin and developmental temperature

The benthic settlement success of American lobster (Homarus americanus) postlarvae is a key factor in population dynamics, with the temperature being a key factor. Given the spatial distribution of the species, its pelagic larvae probably encounter various thermal zones during development. Little information is available on the ability of lobster larvae to acclimate to temperature or if this ability varies among geographic areas. The main objectives of this study were to characterize (i) the settlement behavior of the postlarvae in relation to (a) temperature during larval development and (b) the geographic origin of the maternal parent and (ii) the behavioral response of postlarvae with different thermal histories in the presence/absence of a thermocline. Results did not support the hypothesis of thermal adaptation among local populations, as settlement behavior of postlarvae did not differ among females from different geographic regions. In contrast, larval survival and settlement behavior and postlarval energetic conditions varied with development temperature. Behavioral plasticity in the benthic settlement was observed in relation to temperature structure of the experimental water column. This study suggests that there may be links between development temperature and the natural variability in survival and settlement of American lobsters. Findings emphasize the need for an integrated approach in lobster recruitment studies with the inclusion of behavior in dispersion models.     

High fluid shear strain causes injury in silver shark: Preliminary implications for Mekong hydropower turbine design

The Lower Mekong Basin is facing unprecedented threats to fish diversity from hydropower development. There is increasing pressure on developers and construction authorities to design solutions to improve fish survival through turbines, thus protecting the resources in regions being developed for hydropower. A hydraulic characteristic of hydropower turbines with known fisheries impacts is fluid shear stress. Elevated shear stress occurs where rapidly flowing water passes near spillways, screens and within turbine draft tubes. Shear stress can have adverse impacts on fish, but no work has assessed whether this holds true for Mekong River species. A flume was used to determine critical tolerances of silver shark, Balantiocheilos melanopterus (Bleeker), to shear stress rates at a high‐velocity jet which simulated a hydropower turbine. Fish were assessed for injury or mortality following exposure. Results were compared against a no‐shear control. Injury and mortality were greater at higher shear stress exposures. Injuries occurred at all shear exposure levels with mortality at shear levels higher than 600/s. This approach should help design future hydropower turbines if data on other species demonstrate similar results. If the likelihood of adverse impact is high, then shear stress will need to be considered in the design of future hydropower facilities.     

草鱼呼肠孤病毒疫苗的研发与应用

正随着水产养殖产业的不断扩大,我国已成为世界上最大的水产品生产消费和进出口国家。2000年至2013年,水产养殖产量以每年5%~6%稳步增长,在2013年,中国水产养殖产量达4.542×10~7t,占全球水产养殖总产量的60%以上~[1]。根据世界粮农组织数据显示,2015年我国水产养殖总量达7.430×107 t。这些数据表明我国水产养殖业不仅保障了中国水产品的市场供应,也对世界水产品供     

扬州市稻田高效种养模式应用现状及发展对策

近年来,扬州市根据国家农业供给侧结构性调整要求,充分利用自然资源禀赋,开展了多种形式稻田种养模式的示范与推广。本文阐述了扬州市稻鸭共作、稻虾共作以及稻田改作荷藕-虾共作等高效种养模式的应用现状,以单纯种稻为对照,比较了各种模式的生产效益;分析了稻田高效种养模式示范推广过程中存在的主要问题,并提出了促进稻田高效种养模式可持续发展的若干对策。