斑节对虾性腺组织、细胞的原代培养条件优化

通过观察不同成分培养基及不同培养方法培养的斑节对虾性腺组织及细胞原代培养生长情况,分析细胞活力及生长相关基因表达情况,判断3种改良培养基的适用条件,为进一步细胞培养试验提供支持。试验结果表明,以L-15培养基为基础培养基,不同配方的培养效果差距较大,其中机械分离法可成功培养离体斑节对虾性腺组织,而酶解法与3号培养基结合效果较好;在培养过程中可见离体卵母细胞多呈悬浮生长,部分可见分裂相,离体精原细胞多呈贴壁生长,1号、2号培养基中的细胞可维持良好生长状态达一周以上;CCK测试结果表明,机械分离的性腺组织和酶解法分离的性腺细胞分别在1号、3号培养基中有更高的细胞活力,而2号培养基中的性腺组织及细胞在两种培养方法下的活力差别不大。进一步的荧光定量PCR检测了离体培养过程中MAPK信号通路相关基因的表达变化情况,结果表明,Ras、c-Mos、MEK1、ERK基因在卵母细胞中表达变化更显著,且c-Mos基因与离体细胞生长发育情况呈正相关。本试验系统性地筛选了适宜斑节对虾性腺组织、细胞的原代培养方法,为了解培养过程中的生理过程变化提供了相关参考数据。     

Partial replacement of fishmeal by fermented soybean meal in diets for juvenile white shrimp (Litopenaeus vannamei)

As an important feed ingredient, fermented soybean meal (FSM) has been widely used in aquatic animals due to its stable sources and reasonable price. Here, we evaluated the potential for replacement of fishmeal (FM) with FSM in diet of Litopenaeus vannamei. Five isonitrogenous (410 g/kg) and isolipidic (80 g/kg) diets were formulated: a control diet containing 320 g/kg FM and four experimental diets in which FM in control diet was replaced by FSM at 10 (FSM10%), 20 (FSM20%), 30 (FSM30%) and 40% (FSM40%). An 8‐week feeding trial was conducted in fifteen fibreglass tanks with 50 shrimps per tank. After 8 weeks trial, FSM20% had significantly enhanced growth performance (p < 0.05). No significant difference was found in body composition and digestive enzyme activities of all groups (p > 0.05). Through real‐time quantitative PCR analysis, tor and s6k expression levels of FSM20% were significantly up‐regulated (p < 0.05). Results of western blot showed that the phosphorylation of S6K was not significantly affected by different dietary treatments (p > 0.05), which suggested mTOR signalling pathway was not affected by FSM diets. Based on the above data, 20% replacement of FM with FSM was reasonable and advantageous for L. vannamei diet.     

Advances in Phenazines over the Past Decade: Review of Their Pharmacological Activities,Mechanisms of Action,Biosynthetic Pathways and Synthetic Strategies

Phenazines are a large group of nitrogen-containing heterocycles, providing diverse chemical structures and various biological activities. Natural phenazines are mainly isolated from marine and terrestrial microorganisms. So far, more than 100 different natural compounds and over 6000 synthetic derivatives have been found and investigated. Many phenazines show great pharmacological activity in various fields, such as antimicrobial, antiparasitic, neuroprotective, insecticidal, anti-inflammatory and anticancer activity. Researchers continued to investigate these compounds and hope to develop them as medicines. Cimmino et al. published a significant review about anticancer activity of phenazines, containing articles from 2000 to 2011. Here, we mainly summarize articles from 2012 to 2021. According to sources of compounds, phenazines were categorized into natural phenazines and synthetic phenazine derivatives in this review. Their pharmacological activities, mechanisms of action, biosynthetic pathways and synthetic strategies were summarized. These may provide guidance for the investigation on phenazines in the future.     

Erythropoietin inhibits adipogenesis of mouse bone marrow mesenchymal stem cells by activating ERK and p38 MAPK

AIM:To explore the role of erythropoietin (EPO) in the differentiation of mouse bone marrow-derived mesenchymal stem cells (MSCs) into adipocytes. METHODS:The mouse MSCs were cultured using routine methods. The cells were induced to differentiate by the cocktail medium containing 3-isobutyl-1-methylxanthine, insulin and dexamethasone, and the cells in the experiment group were treated with EPO. On the 20th day of induced differentiation, the cells were detected by oil red O staining. The mRNA expression of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα), fatty acid binding protien 4 (FABP4) and adiponectin were determined by real-time fluorescence quantitative PCR. The phosphorylation levels of PPARγ, extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (p38 MAPK) were measured by Western blotting. MTT assay was adopted to detect the proliferation. RESULTS:During adipogenic induction, EPO decreased lipid accumulation, and inhibited the adipogenic differentiation of MSCs without cytotoxicity. The mRNA expression of PPARγ, C/EBPα, FABP4 and adiponectin was significantly inhibited in induced cells. Moreover, EPO enhanced the activity of both p38 MAPK and ERK, and increased PPARγ phosphorylation. CONCLUSION: EPO significantly inhibits differentiation of mouse bone marrow-derived MSCs into adipocytes in vitro via reducing the mRNA expression of PPARγ, C/EBPα, FABP4 and adiponectin, which may be mediated by the p38 MAPK and ERK signaling pathways.     

Floridean Starch and Floridoside Metabolic Pathways of Neoporphyra haitanensis and Their Regulatory Mechanism under Continuous Darkness

Floridean starch and floridoside are the main storage carbohydrates of red algae. However, their complete metabolic pathways and the origin, function, and regulatory mechanism of their pathway genes have not been fully elucidated. In this study, we identified their metabolic pathway genes and analyzed the changes in related gene expression and metabolite content in Neoporphyra haitanensis under continuous dark conditions. Our results showed that genes from different sources, including eukaryotic hosts, cyanobacteria, and bacteria, were combined to construct floridean starch and floridoside metabolic pathways in N. haitanensis. Moreover, compared with those in the control, under continuous dark conditions, floridean starch biosynthesis genes and some degradation genes were significantly upregulated with no significant change in floridean starch content, whereas floridoside degradation genes were significantly upregulated with a significant decrease in floridoside content. This implies that floridean starch content is maintained but floridoside is consumed in N. haitanensis under dark conditions. This study elucidates the “floridean starch–floridoside” metabolic network and its gene origins in N. haitanensis for the first time.     

数字普惠金融对农业产业化影响研究

【目的 】基于数字普惠金融和农业产业化的视角,探究数字普惠金融与农业产业化水平的作用机制,为建设“产业韧性强”的农业强国的相关政策制定提供决策参考。【方法 】文章基于2011—2020年全国31个省（市、自治区,不包括港澳台）的省级面板数据,先对农业产业化水平进行测度,进而使用固定效应模型,从数字普惠金融覆盖广度、使用深度、数字化水平分维度探究数字普惠金融对农业产业化的影响机制。【结果 】数字普惠金融对我国农业产业化发展具有显著的正向促进作用,数字普惠金融覆盖广度能够缓解农业产业化中金融排斥现象发生,数字普惠金融使用深度能满足农业产业化需求,数字普惠金融数字化程度的提升能为农业产业化提供更多的金融服务。【结论 】应完善农村普惠金融基础设施建设、强化农村金融服务多样化、提升农村普惠金融数字化管理程度,要充分发挥数字普惠金融的积极影响,助力农业产业化发展。     

新发展理念下饲料企业财务风险分析

新发展理念对我国经济、环境及自然等方面提出了更新的要求,完善市场经济体制,更好的建立现代化的经济体系,这对饲料企业而言是机遇也是挑战,饲料企业将面临更加复杂的经营环境,但同时也是其发展壮大的大好时机.财务风险是饲料企业经营管理中不可避免的风险,与饲料企业的发展壮大息息相关,新发展理念下饲料企业更应重视财务风险控制.本文...     

优化农村金融生态的法治路径

通过对农业金融生态系统输入、运行、输出流向中的问题分析,展示了农村金融生态系统脆弱性表现及其背后的深层根源。在此基础上,分别着眼于农村金融生态的系统性、适应性和动态性,从法律政策规范的供给结构、内在品质和前瞻把握3个方面提出了优化农村金融生态的法治路径。     

一类分数阶金融系统的混沌同步

研究了一类分数阶金融系统的混沌同步问题，基于Lyapunov稳定性理论和分数阶微积分的相关理论，给出了两种实现同步的控制方案，仿真算例表明了方法的有效性.