Up-regulation of cytokeratin expression in canine distemper virus-infected canine footpad epidermis

Cytokeratin expression was assessed in footpad epidermis from dogs using immunohistochemistry. Four groups of dogs were studied: dogs with experimentally induced distemper and with canine distemper virus (CDV) in footpad epidermis (group 1, n = 7); dogs with experimentally induced distemper and without CDV in footpad epidermis (group 2, n = 4); inoculated dogs without distemper and without CDV in the footpad epidermis (group 3, n = 8), and noninoculated dogs without distemper (group 4, n = 2). No increase in thickness of the footpad epidermis was present in any of these groups. Sections of metacarpal or metatarsal pads were stained for cytokeratin (CK)14 (proliferation-associated), CK10 (correlated with early differentiation), and for involucrin (associated with terminal differentiation). CK14 was present in basal keratinocytes of all groups, but staining intensity decreased towards the corneal layer in groups 2-4, but not in group 1. CK10 was present in the spinous and granular layer of all groups, but staining of the granular layer was much stronger in group 1. Involucrin was present in the granular layer of footpads of group 1 and only in the upper part of this layer in groups 2-4. The results demonstrate increased staining intensity and/or wider distribution within the footpad epidermis in group 1 dogs when compared to the other groups. This was interpreted as up-regulation in expression of these proteins. These findings suggest that presence of CDV antigen and mRNA in footpad epidermis was associated with an increase in expression of CK14, CK10 and involucrin. The potential role of this up-regulation in cytokeratin expression in the development of CDV-induced digital hyperkeratosis remains speculative at the moment and requires further studies.     

长期低温作用下垂穗披碱草保护酶活性变化及其牧草生态适应性

本文通过对高寒山区耐寒性强的垂穗披碱草保护酶活性在生长季中变化以及一理指标测定分析，探讨了该牧草适应低温生长的耐寒机制。结果表明：在气温较高的６－８月（１０℃牧草可溶性糖、淀粉含量下降，气温降低时出现积累，该牧草光合代谢表现出对低温的较高耐受力。     

The effect of food concentration on the scope for growth and growth performance of Ruditapes decussatus (L.) seed reared in an open-flow system

Ruditapes decussatus (L.) seed, 1.6 mm in length, was reared in an open-flow system for 28 days at different concentrations of food: 15, 50, 100, 200 and 300 Isochrysis galbana, clone T-ISO, cells μL^?1. Rates of ingestion, absorption, and respiration were measured during the experiment and used to calculate the energy balance. Rate of ingestion and absorption efficiency were the primary physiological processes governing seed growth. Ingestion rates increased with food concentration, up to a maximum of 100 cells μL^?1. Greater increases in concentration resulted in a decrease in ingestion. Clearance rates were inversely correlated to food concentration. Absorption efficiency, estimated using the Conover method, also decreased with increasing concentrations of food. Respiration rates were independent of food concentration. Potential growth rates were lower than actual growth rates for each of the concentrations tested, although the effect of food concentration on actual and potential growth was equal, with maximum growth occurring at a concentration of 50 cells μL^?1. Thus, SFG (‘scope for growth’) is a good qualitative estimator of actual growth, but a poor quantitative estimator.     

高校实验室环境建设与管理问题及对策研究

高校实验室作为实践性教学环节的重要组成部分,其建设与管理的优劣对于培养学生的创新精神和实践能力具有十分重要的作用.从高校实验室建设与管理涉及的硬环境和软环境建设存在的问题入手,提出加强高校实验室环境建设与管理的基本对策.     

无锡市河埒口高产鱼池水质研究 Ⅰ.水化学和初级生产力

本文总结了1977年5—8月对无锡河埒口高产池塘水化学研究的成果。该地区高产池主要离子含量适中,pH稳定。有效氮含量平均1.38毫克/升,其中铵氮占61％,亚硝酸氮占14％,硝酸氮占 25％。溶解活性磷(P_2O_5)平均为 0.028毫克/升。N/P 为 61—139。COD_(Mn)为 13.3毫克/升。磷是初级生产力的限制因素。 经初步分析表明:池水中溶解有机物与悬浮有机物约各占一半,而有机碎屑占有机悬浮物的 2/3到 4/5。平均补偿深度 77—80厘米,为平均透明度的 2.4倍。5—8月间平均水柱日初级毛生产量为9.41—10.09克氧/米~2·日。池水氧气的消耗,池鱼约占20％,“水呼吸”约占70％,底质约占 10％。氧气来源约 60％靠光合作用,40％靠空气溶解。     

银中杨扦插繁殖技术初探

银中杨是具有很高观赏价值的杨树品种之一,苗木繁育上有一定难度,为提高银中杨扦插育苗成活率,试验采用清水浸泡、IBA(吲哚乙酸)及NAA(萘乙酸)3种方法进行银中扬生根处理。结果表明:硬枝扦插中覆地膜配合NAA100mg·L-1处理效果最好,扦插成活率达88%;软枝扦插中IBA50mg·L-1处理的扦插成活率86%。     

文蛤稚贝室外越冬技术的研究

通过对文蛤稚贝室外网箱越冬技术研究，解决了文蛤育苗产业化生产中稚贝在北方地区越冬难度大越冬成活率低等技术问题，找出一条适合北方特点的有效越冬方法及途径。2000年10月至2001年5月在盘山县双良育苗场2个室外越冬池，放入20个越冬网箱，稚贝2．0亿枚，稚贝越冬密度44万枚／m^2，平均壳长1000μm，进行了室外越冬试验。在盐度25．8—28．8，pH值7．5—8．5，DO7．0mg/L以上，用直径5．08cm潜水泵在池内间断性循环水，自然水温条件下，越冬后稚贝共计1．612亿枚，平均壳长1095μm(最大l650μm)，成活率达80．6％。试验结果表明，其越冬方法在北方地区是可行的，为文蛤苗种产业化生产提供了可靠的技术保障。     

Cellulose digestion by common Japanese freshwater clam Corbicula japonica

ABSTRACT:   Cellulose digestion by Corbicula japonica was investigated according to the hypothesis that without any symbiotic aid, this organism can utilize cellulose as a carbon source. Enzymatic studies revealed the complete cellulase activity of this species, and molecular cloning resulted in the isolation of cDNA with an ORF encoding a 596-amino-acid protein that shares significant homology with abalone and termite cellulases with an amino acid identity of 52.2% and 50.5%, respectively. The isolated cellulase had a carbohydrate-binding module at the N-terminal region that was also reportedly present in abalone cellulase, and its mRNA were specifically expressed in the digestive gland. These findings strongly support the assumption that C. japonica has an endogenous cellulose, as well as abalones and termites. It is further believed that C. japonica plays an important roll in decomposing cellulose, and consequently contributes to the carbon-cycle in the aquatic environment, as termites do in terrestrial forests.     

淀山湖河蚬繁殖周期和增殖研究

本文研究了淀山湖河蚬的性腺成熟、繁殖周期的规律。雌雄河蚬在壳长12-13毫米时性腺已达成熟期。河蚬繁殖高峰期是从六月初一直延续到九月底,捕捞季节可推迟到十月初或十月中旬,捕捞网孔不宜过小。研究结果为淀山湖河蚬的增殖、合理捕捞提供科学资料。