Effect of cortisol and triiodothyronine bath treatments on the digestive enzyme profile and growth of Catla catla larvae during ontogenic development

Digestive enzyme profile is a good indicator of the nutritional and health status of the fish. The present investigation aims to evaluate the effect of exogenous bath treatment of hormones, cortisol and triiodothyronine, on the digestive enzyme activities and growth of carp Catla catla (Ham.) during ontogenic development. Catla larvae (4 days old) were given bath treatment with cortisol (hydrocortisone, 0.2 mg L^?1), 3,5,3′‐triiodothyronine (T3, 2.5 mg L^?1) and a combination of cortisol and T3 for 30 min. Digestive enzyme profile was recorded on every third day and was continued for 30 days. Larvae were fed with live food for initial 14 days and then weaned to mix feeding of live food and prepared diet. Significantly (P < 0.05) higher amylase, total protease, trypsin, chymotrypsin, lipase, chitinase and chitinobiase activities were found in the hormone‐treated groups compared to the control one during ontogenic development. Among the treated groups, amylase activity was highest in cortisol‐treated larvae. Total protease, trypsin, chymotrypsin, lipase, chitinase and chitinobiase activities were significantly (P < 0.05) higher in larvae exposed at combined treatment of cortisol and T3 compared to the other two groups in most sampling days. Average length, weight and specific growth rate of treated larvae were higher compared to the control one. The combined bath treatment of cortisol and triiodothyronine influenced the digestive enzyme activities of catla larvae and thereby enhanced the growth at early developmental stage. This helps the larvae to overcome the problems associated with early developmental stage.     

秸秆复合有机酿热物对大棚土壤环境的影响

为解决黑龙江省早春大棚土壤温度低及设施土壤环境恶化问题,以‘千禧’番茄为材料,研究秸秆+牛粪(NGH)、秸秆+马粪(MGH)、秸秆+羊粪(YGH)、单一秸秆(JG),以未进行反应堆技术为对照(CK),对早春大棚‘千禧’番茄土壤温度、土壤理化性状、酶活性及微生物群落结构的影响。结果表明,与对照相比,各处理降低了土壤pH,提高了土壤温度、土壤EC、碱解氮、速效钾、有机质含量及土壤蔗糖酶、脲酶、磷酸酶、过氧化氢酶活性。经过秸秆生物反应堆处理的20 cm土层温度有明显的提升,其中秸秆+羊粪处理在反应启动后提升土壤温度效果最好;秸秆+羊粪(YGH)处理提高了土壤速效磷含量,是对照的2倍;秸秆+羊粪(YGH)处理土壤中4种酶活性均处于最高水平,分别比对照提高了91.9%、220%、18.5%、7.3%。各处理微生物多样性指数均显著高于对照,变化规律一致为秸秆+羊粪(YGH)>秸秆+牛粪(NGH)>秸秆+马粪(MGH)>秸秆(JG)>对照(CK);秸秆+羊粪(YGH)及秸秆+牛粪(NGH)处理对糖类、氨基酸类、酯类、醇类、胺类、酸类6类碳源的利用能力最强,显著高于其他处理和对照。应用主成分分析和聚类分析方法将大棚番茄土壤分为4个等级,秸秆+羊粪(YGH)处理为第一级,秸秆+牛粪(NGH)处理为第二级,秸秆+马粪(MGH)及单一秸秆(JG)处理为第三级,对照(CK)为第四级。应用秸秆复合有机酿热物生物反应堆促进了土壤环境的改善,以秸秆+羊粪(YGH)作为复合有机酿热物效果最佳。     

异色瓢虫两个单倍体基因型的生物学特性比较

势单倍型异色瓢虫生物学特性的差异，在室内条件下以豌豆修尾蚜Megoura japonica（Matsumura）为食物，观察这两个单倍型的幼虫期死亡率和发育历期、雌成虫终身产卵量和卵孵化率等生物学参数。结果表明，单倍型-I和单倍型-Ⅱ的幼虫发育历期差异显著，分别为14.38和13.75 d；单倍型-I在幼虫各龄期的死亡率均低于单倍型-Ⅱ，分别为13.33%和29.20%（1龄）、5.49%和13.75%（2龄）、1.16%和4.35%（3龄）、2.35%和10.61%（4龄）。单倍型-I和单倍型-Ⅱ的成虫终身产卵量无显著差异，分别为936粒和887粒；卵孵化率差异显著，单倍型-I的卵孵化率（64.53%）高于单倍型-Ⅱ（60.99%）。综合来看，异色瓢虫的两个单倍型在自然界存在数量差异的原因可能是其在生殖和发育上的差异造成的。     

Injury Induces a Change in the Functional Characteristics of Cells Recovered from Equine Tendon

Injury initiates a repair process characterized by influx of fibroblasts and the rapid formation of fibrous scar tissue and subsequent tissue contraction. The response to injury and behavior of the different tendon fibroblast populations, however, has been poorly characterized. We hypothesized that the fibroblasts recovered from tendon with acute injury would exhibit different cell properties relating to adhesion, migration and tensegrity. To test this hypothesis we evaluated the ability of fibroblasts recovered from normal and injured equine superficial digital flexor tendons (SDFTs). The injured tendon-derived cells showed greater contraction of the collagen gel but poorer adhesion to pepsin-digested collagen, and migration over extracellular matrix proteins compared to normal SDFT-derived fibroblasts. Thus, the cells present within the tendon after injury display different behavior related to wound healing.     

农产品滞销现象与供给过剩的形成机制

农产品供给过剩是农户在信息不对称条件下,基于自身生产要素禀赋的理性选择。本文从供给层面,以“产业内部农户数量不确知”为突破点,运用生产——销售二阶段模型,解释农产品供给过剩的形成机制。模型分析表明,农户农产品期望收益越高,行业内部农户数量越大,发生供给过剩的可能性越大。考虑农户对行业内部总体农户数量估计存在偏差情况下,个体农户的主观猜测与客观分布的偏差越大。行业内出现供给过剩的可能性越大。本文从完善总量信息方面给出对策建议。     

Evaluation of Schizophyllum commune Fr. potential for biodegradation of lignin: A light microscopic analysis

Lignin biodegradation potential of Schizophyllum commune Fr. is studied by using sound wood blocks of Ailanthus excelsa, Azadirachta indica, Tectona grandis, Eucalyptus sp. and Leucaena leucocephala. Initially, in vitro wood decay test showed minor weight loss, but it became rapid after one month. After 120 days of incubation, weight loss was minimum in T. grandis (24.05%) whereas it was maximum in A. excelsa (34.44%). Treated test blocks were characterised by enlargement of pits on ray cell wall, formation of additional boreholes in rays, separation of fibres and cell wall thinning and formation of ‘U’-shape notches. Fungal hyphae moved through the xylem cell lumen, and intercellular spaces formed in response to separation of fibres. Hyphae traverse in adjacent cell through the cell wall pits or by making additional boreholes. In all the species studied, xylem fibres and parenchyma (axial and ray) cells were more susceptible while vessels were resistant to fungal attack. In advanced stage of decay, fibres and axial parenchyma lost their rigidity while vessel walls showed uneven thinning. In the tension wood, G-fibres remained unaffected initially but loosening and separation of gelatinous layer facilitated fungal action and showed similar pattern of cell wall deterioration. Among the wood of different species studied, Tectona was more resistant whereas Ailanthus was more susceptible to fungal attack.     

牛初乳与牛常乳中乳脂肪球膜蛋白质的组成及功能的对比研究

利用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate polyacrylamide gel electropheresis,SDS-PAGE)将牛初乳与牛常乳中乳脂肪球膜蛋白质的组成部分进行分离鉴定,发现牛初乳与牛常乳中乳脂肪球膜蛋白质的组成存在较大的差异,且在牛初乳中鉴定出628种乳脂肪球膜蛋白质,牛常乳中鉴定出487种乳脂肪球膜蛋白质.由基因本体(gene ontology,GO)功能注释分析发现,在生物过程中生物调控作用是牛初乳和牛常乳中乳脂肪球膜的主要生物过程.在分子功能上,牛初乳的乳脂肪球膜蛋白质的绑定作用大于牛常乳.在细胞组成上,牛初乳乳脂肪球膜蛋白质参与细胞外区域远远大于牛常乳.通过京都基因与基因组百科全书系统(Kyoto Encyclopedia of Genes and Genomes,KEGG)代谢通路分析可知,牛初乳和牛常乳乳脂肪球膜蛋白质参与的代谢途径不同,表明牛初乳在日后的生产加工中更具有利用价值.     

牛奶来源质量监督调查报告

为保证牛奶来源的质量和食品安全,对42个牧场进行随机检查,发现挤奶环境差、现场管理不当、人为搀假问题严重.其中酒精实验不合格和干物质低的牛奶数量最多,酒精阳性奶共48.27 t,干物质低奶54.36 t,分别占总问题奶的37%和44%.希望引起广大奶牛养殖户和乳品企业的重视.     

The Cytological Status of Plants Regenerated from Shoot-Meristem Culture of Pisum sativum L

The cytological status of plantlets regenerated from shoot apical meristems of Pisum sativum was investigated. Chromosome counts in root apices of in vitro regenerated plants showed a preponderance of diploid cells. Moreover, the karyotypes of root-tips from plants derived from culture and from normal plants were basically the same. Topics such as the treatment of chromosomal armlength data, simple statistical comparison of samples derived from normal and regenerated plants are discussed.     

Lipid hydroperoxidase activity of myoglobin and phenolic antioxidants in simulated gastric fluid

Our recent study demonstrated the potential of gastric fluid at pH 3.0 to accelerate lipid peroxidation and cooxidation of dietary constituents in the stomach medium. Metmyoglobin is known to catalyze the breakdown of lipid hydroperoxides to free radicals, a reaction that could enhance the propagation step and general lipid peroxidation. During this reaction, a part of the free radicals is autoreduced by metmyoglobin. At pH 3.0, metmyoglobin at low concentration was almost 7 x 10(4) times as effective as at pH 7.0 in enhancing the rate of lipid peroxidation. Our study demonstrated that metmyoglobin, at a low concentration (approximately 1:30), as compared with that of the hydroperoxides in the lipid system, worked prooxidatively increasing the amounts of linoleate hydroperoxides. However, at a high concentration (approximately 1:3), metmyoglobin acted antioxidatively and decomposed hydroperoxides, whose concentrations then remained at zero for a long time. Catechin, a known polyphenol, supports the inversion of metmyoglobin catalysis, from prooxidation to antioxidation. The antioxidative activity of the couple metmyoglobin-catechin was better at pH 3.0 than at pH 7.0, indicating that this reaction is more dependent on metmyoglobin than on catechin. During this reaction, catechin or quercetin not only donates reducing equivalents to prevent lipid peroxidation but also prevents the destruction and polymerization of metmyoglobin. The results of this research highlighted the important and possible reactions of heme proteins and polyphenols as couple antioxidants, working as hydroperoxidases or as pseudo-peroxidases. We hypothesize that the occurrence of these reactions in the stomach could have an important impact on our health and might help to better explain the health benefits of including foods rich in polyphenol antioxidants in the meal, especially when consuming red meat.