Recruitment pattern of muscle fibre type during high intensity exercise (60-100% VO2max) in thoroughbred horses

To consider the optimal training programme for Thoroughbred horses, we examined the recruitment pattern of muscle fibres including hybrid muscle fibres in well-trained Thoroughbred horses. The horses performed exercise at three different intensities and durations; i.e., 100% VO2max for 4 min, 80% and 60% VO2max for 8 min on a treadmill with 10% incline. Muscle samples were obtained from the middle gluteal muscle before, during (4 min at 80% and 60% VO2max), and after exercise. Four muscle fibre types (types I, IIA, IIA/IIX, and IIX) were immunohistochemically identified, and optical density of periodic acid Schiff staining (OD-PAS) in each fibre type, and the glycogen content of the muscle sample, were determined by quantitative histochemical and biochemical procedures. The changes in OD-PAS showed that the recruitment of all fibre types were identical at the final time stage of each exercise bout, i.e., 4 min running at 100% VO2max, and 8 min running at 80% and 60% VO2max. The changes in OD-PAS of type IIA/IIX fibre were very similar to those of type IIX fibre. The recruitment of these fibres were obviously more facilitated by 4 min running at 100% VO2max than by 4 min running at 80% or 60% VO2max. Short duration with high intensity exercise, such as 4 min running at 100% VO2max or 8 min running at 80% or 60% VO2max, is effective to stimulate type IIX fibre and IIA/IIX fibres that have the fastest speed of contraction.     

异叶苦竹胚和胚乳的发育及淀粉粒动态

采用常规石蜡切片法,观察异叶苦竹胚和胚乳的发育过程,部分切片用PAS染色观察胚乳发育过程中的淀粉积累分布动态。结果表明:异叶苦竹合子的休眠期为5天,胚的发育经过二细胞原胚、多细胞原胚、梨形原胚、分化胚和成熟胚阶段,发育类型为禾本型,成熟胚具有胚根、胚芽、盾片、胚芽鞘、胚根鞘、外胚叶等典型禾本科植物成熟胚的结构。胚乳发育包括游离核、细胞化和生长成熟3个阶段,发育类型为核型。授粉后16天左右,淀粉粒开始在细胞核周围积累,以后逐渐增多,充满整个胚乳。     

草鱼头肾发生组织学与免疫组织化学观察

为研究草鱼头肾的组织发生发育,应用组织学技术,对1 ～ 103 dph(day post hatching)的草鱼头肾进行观察分析,描述了头肾的组织结构变化及免疫球蛋白M(IgM)阳性细胞及过碘酸雪夫氏(PAS)阳性细胞的发生和分布.结果显示,6 dph,出现头肾原基,原基中原肾管分化形成的肾小管之间出现散在的干细胞.7 dph至16 dph,造血干细胞逐渐分化成不同类型的细胞,免疫细胞数量逐渐增加;17 dph至103 dph,肾小管逐渐退化至完全消失,网状内皮系统支持下的淋巴造血组织构成头肾的主要部分.40 dph肾上腺细胞团开始出现.65 dph与成鱼头肾的组织结构接近,作为淋巴-肾上腺组织存在.PAS阳性细胞最早在7 dph出现;IgM阳性细胞最早出现于17 dph;之后,IgM阳性细胞及PAS阳性细胞逐渐增多,分布于整个头肾组织.研究表明,65 dph草鱼头肾在组织上发育基本成熟;头肾作为草鱼免疫器官的早期发育可以分为3个阶段:无参与免疫反应的细胞、只具有参与非特异性免疫反应的细胞以及参与非特异性免疫反应及特异性免疫反应的细胞组织结构逐步发育完善.     

Comparative Nile tilapia and silver carp filtration rates of Partitioned Aquaculture System phytoplankton

Nile tilapia (Oreochromis niloticus) and silver carp (Hypophthalmichthys molitrix) held in timed-pulse feeding chambers were provided water dominated either by green algae (Scenedesmus, Ankistrodesmus and Tetraedron) or by cyanobacteria (Microcystis) to compare filtration rates (FRs). FRs were expressed as suspended particulate organic carbon (POC)/kg wet fish weight/h and as phytoplankton units filtered based on counts. Nile tilapia and silver carp filtration significantly reduced phytoplankton number of both taxonomic groups with the larger phytoplankton being filtered proportionally more than the smaller phytoplankton. Nile tilapia FR of green algae was significantly higher than silver carp; however, silver carp FR of cyanobacteria was higher than Nile tilapia. Ivlev's 90% saturation FRs (FR₉₀) in green-algal and cyanobacterial water sources were 702 and 812 mgC/kg/h for Nile tilapia and 414 and 1028 mgC/kg/h for silver carp, respectively. Silver carp were observed to reach these FR₉₀ values at lower POC concentrations than Nile tilapia with both green algae and cyanobacteria.     

牙鲆孵化腺的细胞化学研究

[目的]研究牙鲆胚胎发育过程中孵化腺细胞的分化规律。[方法]采用常规固定、切片方法,利用高碘酸-雪夫染色反应（PAS）对各个发育时期的牙鲆胚胎和孵化后的仔鱼切片进行染色。[结果]典型的孵化腺细胞（阳性细胞）出现于孵化前15h,位于胚胎的前中部,孵化腺细胞的数量和体积均在孵化前达到最大值,且均位于胚胎头部和背部表面。一旦孵化结束,孵化腺细胞的数量和体积均急剧下降,并于孵化后13h消化。[结论]牙鲆胚胎中孵化腺细胞的变化规律与其发育进程密切相关。     

基于PAS2050规范的土地整治碳排放定额测算方法及其应用

[目的] 科学测算土地整治工程过程碳排放,为实施低碳土地整治,实现碳达峰和碳中和目标提供科学参考。[方法] 参照国际建筑领域的PAS2050规范,梳理土地整治工程施工过程碳排放机理。以碳排放系数法为基础,将土地整治工程预算定额转换为碳排放定额,并按照建筑工程概预算的计算思路,测算土地整治工程施工的总碳排放量。[结果] ①土地整治工程碳排放定额是以《土地开发整理项目预算定额》中给定的相关预算定额为基础,运用碳排放系数法计算各个预算定额中所含一定量人力、材料、机械的碳排放量,继而将预算定额转变成碳排放定额,从而实现碳排放总量的计算; ②依据PAS2050规范,土地整治工程碳排放的时空边界清晰,其对象边界、要素边界和碳源类型明确,并据此测算出案例项目碳排放总量为194 225.95 kg。[结论] 碳排放定额法在系统、全面、准确测算建筑施工过程碳排放方面具有较强应用前景,通过编制《土地开发整理项目碳排放定额》标准、开发“土地整治项目碳排放”软件和优化调整定额等方式,把碳排放定额法应用在土地整治实践之中,将有利于促进国土综合整治的节能减排。