piggyBac转座子介导的家蚕细胞转基因研究初探

为探讨稳定转化家蚕细胞表达外源基因的新方法,以家蚕核型多角体病毒(BmNPV)极早期蛋白基因(ie-1)启动子元件驱动新霉素抗性基因(neor),并克隆至具有绿色荧光蛋白基因(gfp)标记的昆虫转座子载体piggyBac中,构建转基因载体pigA3-IE-Neo。以该载体转染家蚕BmN细胞,用终浓度800μg/mL的遗传霉素(geneticin,G418)筛选3个月,获得了稳定转化的细胞,呈现绿色荧光的细胞数达80%以上。通过PCR鉴定证实了细胞基因组DNA中neor基因和gfp基因的存在。     

分子连锁图与家蚕育种

本文概要介绍QTL概念、分子标记及其分子图的构建方法,通过大量的动植物QTL定位取得的成绩以及家蚕分子标记和分子图研究现状的阐述,展望了家蚕分子育种的前景。     

施用镁肥对桑叶产量和叶质的影响

试验表明在Ｋ／Ｍｇ相对较高的酸性土壤,施用镁肥可提高桑叶产量和改善桑叶品质,在生产上可以施用钙镁磷肥或喷施２％硫酸镁溶液。     

省力化培桑技术的研究

省力培桑技术的研究和推广,获得成功,并取利了明显的社会、经济效益。     

防治陡坡桑园严重水土流失的种植模式探讨

 为防治陡坡桑园严重的水土流失,通过4种种植模式对比试验分析查明,实施茶桑间种模式,能够较好地解决陡坡桑园土壤侵蚀严重的问题,其多年平均侵蚀模数由原来的1000t/(km2 ·a)左右,减少到100t/(km2 ·a)左右。建议推广应用这一模式,对严重水土流失的陡坡桑园加以改造,以促进山区坡地开发的永续利用和农业的可持续发展。     

A comparison between marine and terrestrial invertebrate meals for mirror carp (Cyprinus carpio) diets: Impact on growth,haematology and health

Invertebrate meals (e.g. polychaetes and insects) present novel and sustainable high‐quality nutrient sources for use in fish feed formulations. To test this innovative source, an eleven‐week feeding trial was conducted evaluating the effects of replacing the fishmeal (FM) component as an example of a superior protein source (FM CTRL) with ragworm meal (RW, Nereis virens) and/or silkworm pupae (SWP, Bombyx mori) in mirror carp (Cyprinus carpio) diets. Three experimental diets with partial replacement of FM (diets: RW + FM, SWP + FM and RW + SWP + FM) were formulated. All diets were formulated to be iso‐nitrogenous, iso‐lipidic and iso‐energetic. Growth performance and feed utilization indices were assessed, and the feeding trial concluded with the analysis of haematological parameters to provide an indication of carp physiological and health status. Mean weight gain was greatest in mirror carp fed RW + FM (60.83 fish^?1 day^?1; P < 0.05 vs. all other diets) followed by SWP + FM (40.62 g fish^?1 day^?1; P < 0.05 vs. all other diets). The least weight gain was achieved in fish fed FM + SWP + RW+ and FM CTRL (34.34 and 33.96 g fish^?1 day^?1, respectively; not significantly different from each other). Fish fed on RW + FM diet had significantly lower plasma ammonia concentrations than any other dietary groups (P = 0.04). Mirror carp fed on SWP + FM diet (111.52 units mL^?1) were observed to have a marked enhancement in alternative complement activity than FM CTRL (79.21 units mL^?1, P = 0.041). Both ragworm and silkworm pupae meal present attractive sustainable functional feed component in carp diets, with benefits on enhancing growth performance and specific physiological parameters.     

基于改进YOLO v5的复杂环境下桑树枝干识别定位方法

为实现复杂自然环境下对桑树嫩叶处枝干的识别检测,改变当前桑叶采摘设备作业过程中依赖人工辅助定位的现状,解决识别目标姿态多样和环境复杂导致的低识别率问题,提出一种基于改进YOLO v5模型的桑树枝干识别模型(YOLO v5-mulberry),并结合深度相机构建定位系统。首先,在YOLO v5的骨干网络中加入CBAM(Convolutional block attention module)注意力机制,提高神经网络对桑树枝干的关注度;并增加小目标层使模型可检测4像素×4像素的目标,提高了模型检测小目标的性能;同时使用GIoU损失函数替换原始网络中的IoU损失函数,有效防止了预测框和真实框尺寸较小时无法正确反映预测框及真实框之间位置关系的情况;随后,完成深度图和彩色图的像素对齐,通过坐标系转换获取桑树枝干三维坐标。试验结果表明：YOLO v5-mulberry检测模型的平均精度均值为94.2%,较原模型提高16.9个百分点,置信度也提高12.1%;模型室外检测时应检测目标数53,实际检测目标数为48,检测率为90.57%;桑树嫩叶处枝干三维坐标识别定位系统的定位误差为(9.498 5 mm...     

Effects of dietary mulberry leaf extract on the growth,gastrointestinal, hepatic functions of Chinese giant salamander (Andrias davidianus)

Mulberry leaf extract (MLE), an active substance extracted from mulberry leaves, is known to have a positive effect on several physiological functions. The current study examined the effects of dietary MLE in feed at concentrations 0, 3.0, 6.0, 9.0, 12.0 and 15.0 g/kg on the growth performance and gastrointestinal and hepatic functions of Andrias davidianus for 12 weeks. Results indicated that the final body weight, weight gain rate (WGR), specific growth rate and feed intake (FI) of A. davidianus increased with the increase in the dietary MLE up to 9.0 g/kg and declined thereafter, while the feed conversion ratio (FCR) exhibited an opposite trend. Meanwhile, A. davidianus with a dietary intake of 9.0 g/kg MLE showed higher levels of crude protein in muscles and lower levels of moisture and crude lipid levels in the liver and muscles when compared with the control. In addition, dietary MLE increased the density and length of the villi and decreased the cavity rate in the foregut, enhancing the activities of carbonic anhydrase, H⁺‐K⁺‐ATPase, pepsin, intestinal trypsin, lipase and Na⁺‐K⁺‐ATPase (p < .05) in the stomach. Furthermore, dietary MLE increased the intestinal and hepatic superoxide dismutase activities and total antioxidative capacities but decreased their malondialdehyde contents in A. davidianus. Dietary MLE also significantly increased the immune parameters, and the plasma total protein, albumin and immunoglobulin M contents but significantly decreased the aspartate aminotr‐ansferase, alanine aminotransferase and diamine oxidase activities, and the total bilirubin, direct bilirubin, cholesterol, triglyceride and endotoxin contents (p < .05). In conclusion, a quadratic regression analysis of WGR and FCR indicated that the optimum level of MLE for A. davidianus was between 8.21 and 8.30 g/kg of the diet.     

果桑地表覆膜对桑白果病发病及果实品质的影响

以果桑(Morsu alba L.)品种大十(M.alba cv.Big ten)为材料,分别覆盖聚乙烯白色地膜、黑色地膜和银黑反光膜,在果桑萌芽开花前于行内覆盖,比较了开花前不同地表覆膜对果桑果实桑白果病发病率以及果实品质的影响。结果表明,不同地膜覆盖均能显著降低果桑果实桑白果病的发病率,对成熟果实的可滴定酸含量有降低的趋势,同时也显著降低了果实可溶性固形物、花青素和抗坏血酸的含量。说明地表覆膜可以有效预防桑白果病的发生,但是对果实品质的影响尚待进一步试验确认。     

桑树修复土壤重金属污染的研究进展

重金属污染修复已成为当前国际环境科学研究的热点问题,利用桑树修复土壤重金属污染也是一种有效的植物修复技术。笔者简单介绍了土壤重金属与植物修复技术的概念,并阐述了桑树的生长特性,桑树生长与土壤中镉、铅、锌、砷等重金属元素的关系,并结合江西省土壤重金属污染的形势,探讨了桑树作为江西省土壤重金属污染修复树种的潜力。