2019年农机行业10大营销事件

管理学家德鲁克指出,基于顾客,企业只有两项最基本的职能:营销和创新.在当下农机行业进入存量竞争阶段,想要跳出同质化的红海,创新和营销变得特别重要. 2019年已过去,但它留下的印记却是深刻的,尤其是在农机营销领.笔者为大家整理出过去一年农机行业有重大影响的营销事件.     

Jaagsiekte sheep retrovirus found in milk macrophages but not in milk lymphocytes or mammary gland epithelia of naturally infected sheep

Jaagsiekte sheep retrovirus (JSRV) causes ovine pulmonary adenocarcinoma. JSRV can be transmitted via infected colostrum or milk, which contain somatic cells (SCs) harboring JSRV provirus. Nevertheless, the cell types involved in this form of transmission and the involvement of the mammary gland remain unknown. We separated adherent cells (macrophages and monocytes) by plastic adherence, and lymphocytes (CD4+ and CD8+ T cells, and B cells) by flow cytometry, from SCs in milk samples from 12 naturally infected, PCR blood test JSRV–positive, subclinical ewes. These cell populations were tested by PCR to detect JSRV provirus. The ewes were euthanized, and mammary gland samples were analyzed immunohistochemically to detect JSRV surface protein. We did not detect JSRV provirus in any milk lymphocyte population, but milk adherent cells were positive in 3 of 12 sheep, suggesting a potential major role of this population in the lactogenic transmission of JSRV. Immunohistochemistry did not reveal positive results in mammary epithelial cells, pointing to a lack of participation of the mammary gland in the biological cycle of JSRV and reducing the probability of excretion of free viral particles in colostrum or milk.     

犬瘟热病毒疫苗株附着蛋白基因的克隆及同源性比较

根据发表的犬瘟热病毒(CDV)参考株Ondetstepoort的序列设计1对引物,以犬瘟热病毒疫苗株感染Vero细胞总RNA为模板,利用RT-PCR扩增出附着蛋白基因843 bp片段,将这个片段连接到pMD18-T载体上,经过PCR鉴定、酶切鉴定得到1个阳性克隆,将阳性质粒进行序列测定,结果表明,该片段与Onderstepoort株核苷酸同源性为95.9%。从基因角度为犬瘟热的预防、诊断和治疗提供理论依据。     

数字林业在天然林保护工程中的应用研究

本文阐述了数字林业的概念及涵义,指出其最初的切入点是国家林业局提出的六大林业生态工程。针对天然林保护工程的现状,提出用数字林业技术解决其存在的问题,构建了基于3S技术的天然林保护工程管理地理信息系统,使天然林保护工程的管理步入规范化、科学化、现代化的轨道。     

Novel Alkaloids from Marine Actinobacteria: Discovery and Characterization

The marine environment is an excellent resource for natural products with therapeutic potential. Its microbial inhabitants, often associated with other marine organisms, are specialized in the synthesis of bioactive secondary metabolites. Similar to their terrestrial counterparts, marine Actinobacteria are a prevalent source of these natural products. Here, we discuss 77 newly discovered alkaloids produced by such marine Actinobacteria between 2017 and mid-2021, as well as the strategies employed in their elucidation. While 12 different classes of alkaloids were unraveled, indoles, diketopiperazines, glutarimides, indolizidines, and pyrroles were most dominant. Discoveries were mainly based on experimental approaches where microbial extracts were analyzed in relation to novel compounds. Although such experimental procedures have proven useful in the past, the methodologies need adaptations to limit the chance of compound rediscovery. On the other hand, genome mining provides a different angle for natural product discovery. While the technology is still relatively young compared to experimental screening, significant improvement has been made in recent years. Together with synthetic biology tools, both genome mining and extract screening provide excellent opportunities for continued drug discovery from marine Actinobacteria.     

酶制剂对水稻秸秆青贮发酵品质及体外消化特性的影响

为探讨纤维素酶、木聚糖酶及两种酶组合添加对水稻秸秆青贮过程中结构性、水溶性碳水化合物组分含量及体外消化特性和发酵品质的影响,试验设4个处理组:1)0.3%蒸馏水(对照组,CO);2)0.3%纤维素酶(CE);3)0.3%木聚糖酶(XE);4)0.15%纤维素酶+0.15%木聚糖酶(组合酶组,CX),分别于青贮3、7、14、30 d后取样分析。结果表明,与CO相比,CE、XE和CX组显著提高了乳酸、葡萄糖、果糖和蔗糖含量,显著降低了pH值、氨态氮、总挥发性脂肪酸、酸性洗涤纤维、中性洗涤纤维、纤维素和半纤维素含量,减少了干物质损失(P<0.05)。酶制剂显著提高了水稻秸秆青贮饲料24、48和72 h时的累积产气量和干物质体外消化率(P<0.05)。青贮末期CX组有最高的乳酸含量(34.13 g·kg^-1DM)、体外产气量(68.27 mL)、干物质体外消化率(61.31%)和最低的pH值(4.36)。与CE和XE相比,CX组水溶性碳水化合物(葡萄糖、果糖和蔗糖)含量更高。综上所述,添加酶制剂可促进结构性碳水化合物的降解,提高水溶性碳水化合物的含量,改善水稻...     

基于CiteSpace的昆虫性别决定基因研究现状与热点分析

为明确国内外昆虫性别决定基因研究的发展历程、研究热点及趋势,为未来研究方向提供参考与建议,本研究整理并筛选了1933—2022年中国知网（CNKI）和Web of Science(WOS)数据库收录的昆虫性别决定基因的论文,运用文献计量学分析软件CiteSpace对发文年代、关键词、作者和机构等进行可视化分析。结果表明：2001—2005年昆虫性别决定基因研究的发文量呈现上升趋势,发文量最多的国家是美国（446篇）,其次是中国（111篇）和日本（88篇）;国内外载文量最多的期刊分别是《昆虫学报》（9篇）和Genetics(94篇);通过关键词共现和聚类分析表明昆虫性别决定在国内外都是广泛关注的热点问题,且国内外研究方向大体一致,研究热点均集中在模式生物上;通过关键词共现和突现词分析发现利用昆虫性别决定基因进行害虫防治是未来研究的新趋势。     

土霉素在黑鲷体内的药物代谢动力学研究

首次报道了黑鲷口服土霉素的药物代谢动力学特征，用高效液相色谱法测定组织中的药物含量，药物在肌肉，血液，肝脏中的平均回归率分别为８５.61%,85.38%,82.005,该方法的检测限可达0.01μg/g，黑鲷１次口服剂量为７５mg/kg的土壤素后，其血液药物浓度－时间数据符合一室开放动力学模型，吸收速率常数（ka)为０.296/h，达峰时间（Ｔamx)为１０.635h,峰浓度（Ｃmax)为１.398μg/ml, 分布半衰期（Ｔ１／２a）为２.339h ,消除半衰期(T1/20β）为46.663h，药时曲线下面积（ＡＵＣ）为１１0.25mg/L.h，黑绸口服药物０.5h后在血液，肥肉，肝脏，肾脏４种组织中就可以检测到药物的存在，药物在１６h的采样点浓度达最高，分别为1.68μg/ml,1.68,2.52,6.77μg/g。     

Fitting growth with the von Bertalanffy growth function: a comparison of three approaches of multivariate analysis of fish growth in aquaculture experiments

Three approaches for multivariate analysis of fish growth in aquaculture experiments with Nile tilapia (Oreochromis niloticus niloticus L.) based on the von Bertalanffy growth curve are presented and compared. The approaches are: an extended Gulland‐and‐Holt (GH) plot, a forced extended GH plot and a multilinear regression analysis for the growth parameter K. All three models provide valuable insight into the major environmental factors influencing the daily growth rate and explain 28–46% of the variance of the observed daily growth rate of the used data set. For all three methods, the modelled parameter is significantly related to the net yield of Nile tilapia and can, therefore, be used for the predictive modelling of management scenarios. The extended GH plot loads the influence of environmental parameters upon L_∞, while the forced extended GH plot and Direct fitting of K load the influence on the growth parameter K. The latter is more in the tradition of aquaculture research. But the forced extended GH plot and Direct fitting of K can only be applied if L_∞ of the cultured species is known, as the selected L_∞ influences the variance in the regression variables.     

Effect of dietary components on the gut microbiota of aquatic animals. A never‐ending story?

It is well known that healthy gut microbiota is essential to promote host health and well‐being. The intestinal microbiota of endothermic animals as well as fish are classified as autochthonous or indigenous, when they are able to colonize the host's epithelial surface or are associated with the microvilli, or as allochthonous or transient (associated with digesta or are present in the lumen). Furthermore, the gut microbiota of aquatic animals is more fluidic than that of terrestrial vertebrates and is highly sensitive to dietary changes. In fish, it is demonstrated that [a] dietary form (live feeds or pelleted diets), [b] dietary lipid (lipid levels, lipid sources and polyunsaturated fatty acids), [c] protein sources (soybean meal, krill meal and other meal products), [d] functional glycomic ingredients (chitin and cellulose), [e] nutraceuticals (probiotics, prebiotics, synbiotics and immunostimulants), [f] antibiotics, [g] dietary iron and [h] chromic oxide affect the gut microbiota. Furthermore, some information is available on bacterial colonization of the gut enterocyte surface as a result of dietary manipulation which indicates that changes in indigenous microbial populations may have repercussion on secondary host–microbe interactions. The effect of dietary components on the gut microbiota is important to investigate, as the gastrointestinal tract has been suggested as one of the major routes of infection in fish. Possible interactions between dietary components and the protective microbiota colonizing the digestive tract are discussed.