我国杉木组织培养技术研究进展

杉木是我国南方特有的速生用材树种,具有生长快、产量高、材质好和用途广的特点,在南方林业生产中占据重要地位。熟悉和掌握杉木的组织培养技术,对促进杉木产业的发展具有重要意义。文中从叶、茎尖、茎段和离体胚等外植体的选择,外植体消毒,愈伤组织和芽的诱导分化,继代增殖培养以及壮苗与生根等方面简述近几年我国杉木组织培养技术的研究进展,对杉木组培快繁中的灭菌技术、培养基筛选和生长调节物质使用水平等技术环节进行评述,同时提出目前研究中存在的几个主要问题和今后的发展方向。     

Glycyrrhetinic acid protects mice from Staphylococcus aureus pneumonia

In the present study, the antimicrobial activity of glycyrrhetinic acid (GA) against Staphylococcus aureus, and its influence on the production of S. aureus alpha-haemolysin (Hla) were investigated, along with the in vivo activity of GA against S. aureus-induced pneumonia. GA could not inhibit the growth of S. aureus, but the secretion of Hla by S. aureus was significantly inhibited by low concentrations of GA in a dose-dependent manner. Furthermore, in vivo data show that GA provides protection against staphylococcal pneumonia in a murine model system.     

湖北核桃良种培育研究初报

摘要：笔者从1999年开始湖北核桃资源调查,初选出50棵优株,经复选、决选、品比试验等。在鄂西南、鄂西北等主产区进行区试,试验与扩大生产示范结合,连续多年多点对其植物学特征、生物学特性、果实经济性状、抗病抗逆性等进行系统观察分析。结果表明：选出的优株EH9909其丰产性、坚果品质、抗核桃褐斑病、核桃细菌型黑斑病能力明显优于湖北省兴山普通核桃。     

Astrocytic responses in the lateral geniculate nucleus of monkeys with experimental glaucoma

Objective To investigate the responses of lateral geniculate nucleus (LGN) astrocytes to experimental glaucoma in monkeys. Animal studied Rhesus monkeys (Macaca mulatta). Procedures Unilateral chronic elevation of intraocular pressure (IOP) was induced in six rhesus monkeys by laser photocoagulation of the trabecular meshwork. Four normal monkeys were used as controls. Immunohistochemistry with antibodies to glial fibrillary acidic protein (GFAP), S100β and parvalbumin was used to specifically label astrocytes and neurons in the LGN. The relative immunointensity (RI) of GFAP was defined as the ratio of intensity between each region of interest to a reference field and compared between the experimental and control groups as a function of percentage optic nerve fiber loss. Ultrastructural changes of LGN astrocytes were examined by transmission electron microscopy. Results An increase in GFAP and S100β immunoreactivity was observed in the LGN layers receiving projections from the experimental glaucoma eyes. Quantitative analysis revealed that the RI of GFAP in both the magnocellular and parvocellular layers connected to the glaucomatous eyes increased in a linear fashion with increasing optic nerve fiber loss. Compared to controls, the RI of GFAP was also moderately elevated in LGN layers connected to the fellow nonglaucomatous eyes. Ultrastructurally, accumulation of glial filaments that occurred throughout the perikaryon and extended into the process in reactive astrocytes was observed in LGN layers of glaucomatous monkeys. Conclusions Reactive astrogliosis occurs in the magnocellular and parvocellular LGN layers of monkeys with unilateral glaucoma. Astrocytes may play an important role in the regulation of LGN microenvironment in glaucoma.     

基于废弃物的微型化学实验与循环经济研究

指出了基于废弃物的微型化学是绿色化学理念在课堂中的具体实践,更是发展循环经济的重要体现。分析了基于废弃物的微型化学实验的产生及研究情况,对循环经济的产生及其内涵予以阐述,重点论述了基于废弃物的微型化学实验中的循环经济理念以及基于废弃物的微型化学实验的优缺点,客观认识其发展优势的同时也要正视其中存在的不足。提出了将循环经济的3R原则贯穿于基于废弃物的微型化学实验中使化学实验真正实现绿色化、标准化、规模化是未来微型化学实验发展的重要方向。     

瘤胃灌注不同来源淀粉对牦牛瘤胃发酵及血清生化指标的影响

本试验旨在探讨瘤胃灌注不同来源淀粉对牦牛瘤胃发酵及血清生化指标的影响.选用3头装有永久性瘤胃瘘管、体况良好、体重相近[( 244±15) kg]的去势牦牛,采用3×3拉丁方试验设计,对照组按照1.2倍维持能量水平饲喂单一燕麦草(未灌注淀粉),玉米淀粉组和抗性淀粉组分别在对照组的饲喂基础上瘤胃灌注玉米淀粉和抗性淀粉900 g/d.试验分为3期,每期试验18 d(15 d预试期和3d采样期).结果表明:与对照组相比,灌注玉米淀粉和抗性淀粉显著降低瘤胃pH(P ＜0.05),极显著降低瘤胃氨态氮含量(P＜0.01),灌注4h后显著提高瘤胃微生物蛋白质和挥发性脂肪酸含量(P＜0.05).在灌注后4和6h,玉米淀粉组和抗性淀粉组血糖含量显著高于对照组(P＜0.05),血清胰岛素、胰高血糖素和甘油三酯含量与对照组相比差异不显著(P＞0.05),血清尿素氮含量显著低于对照组(P＜0.05).结果提示,瘤胃灌注玉米淀粉和抗性淀粉,降低了牦牛瘤胃氨态氮含量,提高了微生物蛋白质和挥发性脂肪酸含量,提高了血糖含量,降低了血清尿素氮含量,说明牦牛能有效利用不同来源的淀粉.     

Dietary supplementation with biofloc promotes growth,improves immune and antioxidant status,and upregulates NF‐κB/Nrf2 signalling molecules and stress resistance in Rhynchocypris lagowskii Dybowski

Bioflocs are rich in a variety of probiotics and bioactive compounds, which have been documented to promote growth, regulate antioxidant status and enhance the immune system. A 60‐day experiment was conducted to investigate the effects on growth, antioxidant and immune status, NF‐κB/Nrf2 signalling molecules and stress resistance in juvenile Rhynchocypris lagowskii Dybowski fed different dietary biofloc supplementations. Four hundred fifty R. lagowskii were fed five experimental diets containing graded levels of biofloc from 0 to 160 g/kg (referred to as B0, B4, B8, B12 and B16, respectively). The results showed that biofloc supplementation markedly promoted growth performance (weight gain rate, specific growth rate); improved amylase, lipase and protease activity; and enhanced the activities of glutathione peroxidase, catalase, total superoxide dismutase, total antioxidant capacity, lysozyme, complement C3, complement C4 and immunoglobulin M in the gill, hepatopancreas, kidney, gut and serum. The malondialdehyde content was significantly reduced with treatment B12. In addition, the levels of heat shock protein 70, heat shock protein 90, interferon‐γ and insulin‐like growth factor I were substantially increased with treatment B12 compared to those with the control treatment. Furthermore, biofloc assisted in regulating the expression of NF‐κB/Nrf2 signalling molecule genes, including NF‐κB, TNF‐α, IL‐1β, IL‐8, IL‐10, TGF‐β, Nrf2, Keap1, Maf, HO‐1, CAT, GPX, GCLC and CuZn‐SOD. Overall, our results suggest that dietary supplementation with biofloc can promote growth, improve immune and antioxidant status, and enhance NF‐κB/Nrf2 signalling molecule expression and stress resistance in juvenile R. lagowskii. A suitable supplementation level of approximately 120 g/kg biofloc is recommended in the present study.     

Effects of enzyme addition on the nutritive value of broiler diets containing hulled or dehulled Chinese double-low rapeseed meals

An in vitro and a feeding trial was conducted to investigate the effect of fibre-degrading enzymes A (xylanase + β-glucanase), B (xylanase) and C (xylanase + cellulase) on the nutritive value of broiler diets containing either hulled (22.5% and 23.5% for 4–21 days and 22–42 days of age, respectively) or dehulled (20% and 21.5%) Chinese double-low rapeseed meals (DLRM). Overall, in vitro digestibility of dry matter (DM) or neutral digestibility fibre (NDF) did not differ (p > 0.05) because of meal types; both crude protein (CP) and NDF digestibility was improved (p < 0.05) because of addition of enzymes B or C either to hulled or dehulled DLRM diets. Birds fed dehulled DLRM diets had a higher (p < 0.05) growth rate, feed efficiency and lower (p < 0.05) feed intake than those fed hulled DLRM diets during the overall phase. Enzyme C addition to dehulled DLRM diets resulted in improved (p < 0.05) growth rate and feed efficiency during 4–21 days of age. Enzymes A and B addition elicited a positive response in feed intake and weight gain (p < 0.05), respectively, but did not affect (p > 0.05) feed efficiency. It would appear that the nutritive value of broiler diets containing Chinese DLRM could be improved by appropriate xylanase-based enzymes. Responses of broilers to fibre-degrading enzymes could be highlighted by hull removal of fed DLRM.