番茄不同部位中糖含量和相关酶活性的研究

 试验将番茄光合产物运转途径上叶片(源) 、运输系统以及果实(库) 区分开, 分别测定其糖的组成和含量以及糖代谢相关酶的活性。结果表明: 番茄光合产物运转途径上从“源”到“库”各部位糖的组成和含量不同。叶肉中果糖的含量最高, 蔗糖的含量最低; 中筋中以果糖和葡萄糖为主; 叶柄维管束中葡萄糖含量最高, 蔗糖含量次之, 果糖含量最低。节间和果柄维管束中主要含有蔗糖。果实维管束以及果实内各部位中则主要含有葡萄糖和果糖, 且两者含量无显著差异, 蔗糖含量很低。萼片中葡萄糖含量最高, 蔗糖含量最低; 果蒂中3种糖含量均较高且无显著差异。番茄叶肉及光合产物运转组织中转化酶活性很低, 而在库器官的非维管组织中转化酶活性较高。果蒂中的蔗糖合成酶( SS) 活性最高, 其次是叶肉和运转组织, 果实内各部位中SS活性较低。在合成蔗糖的器官—叶肉中, 有较高的蔗糖磷酸合成酶( SPS) 活性, 运转组织中的SPS活性较叶肉中降低, 但果柄维管束和果实维管束中则表现出较高SPS活性, 果肉、果胶质胎座及心室隔壁中的SPS活性最低。     

反刍动物瘤胃碳水化合物发酵研究进展

碳水化合物是反刍动物营养的一个重要组成部分，碳水化合物在反刍动物瘤胃的发酵又是其营养吸收利用的一个重要过程。本文根据国内外研究成果，全面综述了碳水化合物的分类及影响反刍动物瘤胃碳水化合物发酵的三方面因素，揭示了反刍动物对碳水化合物的吸收规律，为我国反刍动物饲养提供指导。     

Effects of dietary lipid-to-carbohydrate ratio on growth and carbohydrate metabolism in juvenile cobia (Rachycentron canadum)

This experiment was conducted to investigate the effects of dietary lipid-to-carbohydrate ratio on growth and carbohydrate metabolism in juvenile cobia (Rachycentron canadum). Six isonitrogenous diets were prepared to vary in lipid-to-carbohydrate ratio (g/g) as follows: D1, 2.26; D2, 1.31; D3, 0.78; D4, 0.47; D5, 0.34; and D6, 0.23. Cobias were fed to satiety for 8 weeks. The weight gain and protein efficiency ratio in D1 group were significantly lower than those in other groups (P < 0.05), accompanied by a lower level of feed conversion ratio (P < 0.05). Protein retention efficiency in D4 and D6 and whole body protein in D4 and D5 were significantly higher than those in D1 group (P < 0.05). Survival rate in D4 group was the highest among all groups and was significantly higher than that in D1, D2 and D5 (P < 0.05). In terms of serum triglyceride, D1 and D2 were significantly higher than D6 (P < 0.05). Hepatosomatic index in D3 and D4 was significantly lower than that in D1 (P < 0.05). Fructose-1,6-diphosphatase in D4 was significantly higher than that in D1 and D3 (P < 0.05). Phosphofructokinase in D3 and D4 and malic enzyme in D4 and D5 were significantly higher than those in other groups (P < 0.05). Results indicate that cobia utilizes carbohydrates as energy source more efficiently than it utilizes lipids. The optimal lipid-to-carbohydrate ratio in juvenile cobia diets is 0.47.     

温度对麦秸混合物料厌氧干发酵中糖类水解酶活性的影响

水解酶活性直接影响到秸秆厌氧干发酵的沼气产量。本文以麦秸为主要原料, 配制干物质含量(TS)35%的混合发酵物料, 设置20 ℃、25 ℃、30 ℃、35 ℃、40 ℃ 5种不同温度条件, 发酵周期为35 d, 测定发酵过程中料液的纤维素酶、木聚糖酶、淀粉酶和蔗糖酶的活性变化。结果表明, 沼气产气高峰在35 ℃左右, 20~40 ℃时, 随着温度的升高, 发酵后料液的料液干物质含量(TS)、可挥发固体含量(VS)、C/N均明显下降, 发酵产沼气后, 各处理发酵液 pH都降到7.0以下, 其中40 ℃的pH降低幅度最大。纤维素酶活性在发酵初期较低, 峰值出现也较晚, 温度升高明显有利于提高纤维素酶活性。木聚糖酶的起始活性较高, 整个发酵过程中呈先升高后降低并渐趋于平缓的变化趋势, 20~25 ℃处理的木聚糖酶活性在整个发酵过程中没有明显峰值。淀粉酶的起始活性较低, 但随后迅速升高, 30~40 ℃处理在10 d左右达到峰值后开始下降, 此后酶活力的变化幅度较前期平稳。蔗糖酶的起始酶活力较低, 随后升高迅速, 温度在30 ℃以上时酶活性增加更快, 35 ℃时15 d达到峰值后迅速下降, 下降速度明显大于30 ℃和40 ℃处理。由此可见, 温度对秸秆厌氧干发酵过程中不同水解酶活性的影响还是有所差异的。     

苹果叶片中碳素同化物代谢的研究

对新红星苹果的有果短枝叶、无果短枝叶、叶丛枝叶、发育枝叶中总糖、还原糖、蔗糖、淀粉含量进行了分析。结果表明,叶片中不同类型的碳水化合物含量随着叶片的迅速生长而逐渐下降,而后随着叶片的发育成熟,其含量呈逐渐递增趋势,但随着叶片的衰老又呈逐渐下降的趋势。不同枝类叶中不同类碳水化合物含量变化有一定的差异。     

螺旋环剥对‘糯米糍’荔枝坐果与碳水化合物及激素的影响

研究结果表明,幼‘糯米滋’荔枝主要螺旋环剥能减少碳水化合物向根系转运,从而增加叶片和果实中的碳水化合物含量,增多果实中赤霉素类物质和降低脱落酸类物质含量。坐果率的提高与赤霉素／脱落酸的比值较高关系密切。     

Oral chromium picolinate and control of glycemia in insulin-treated diabetic dogs

Chromium is an essential dietary trace mineral involved in carbohydrate and lipid metabolism. Chromium is required for cellular uptake of glucose, and chromium deficiency causes insulin resistance. Chromium supplementation may improve insulin sensitivity and has been used as adjunct treatment of diabetes mellitus in humans. In this study, 13 dogs with naturally acquired diabetes mellitus were treated with insulin for 3 months, then with insulin and chromium picolinate for 3 months. Dogs weighing <15 kg (33 lb: n = 9) were administered 200 microg of chromium picolinate PO once daily for I month, then 200 microg of chromium picolinate twice daily for 2 months. Dogs weighing >15 kg (n = 4) received 200 microg of chromium picolinate once daily for 2 weeks, then 200 microg twice daily for 2 weeks, then 400 microg twice daily for 2 months. Type of insulin, frequency of insulin administration, and diet were kept constant, and insulin dosage was adjusted, as needed, to maintain optimal control of glycemia. Mean body weight, daily insulin dosage, daily caloric intake, 10-hour mean blood glucose concentration, blood glycated hemoglobin concentration, and serum fructosamine concentration were not markedly different when dogs were treated with insulin and chromium picolinate, compared with insulin alone. Adverse effects were not identified with chromium picolinate administration. Results of this study suggest that, at a dosage range of 20-60 microg/kg/d, chromium picolinate caused no beneficial or harmful effects in insulin-treated diabetic dogs.     

The fermentative capacity of growing pigs and adult sows fed diets with contrasting type and level of dietary fibre

Adult sows have a more developed gastro-intestinal system than young growing pigs resulting in a superior capacity to digest fibrous components. The main objective of this study was to describe the capacity of sows and growing pigs to digest the fibre components in concentrated low dietary fibre (DF) diet and two high DF diets similar in DF but with contrasting DF solubility. Six sows and four growing pigs were fitted with a simple T-cannula at the terminal ileum. Each balance experiment consisted of a 7-day initial period followed by a 3-day collection of faeces and a 2 or 3-day collection of ileal digesta for growing pigs and adult sows, respectively. When feeding diets with high proportions of soluble non-starch polysaccharides (NSP), the difference in fermentation capacity between growing pigs and adult sows was small. The adult sows showed a higher fermentative capacity, evidenced by a higher fermentation and a higher methane production, when high fibre diet with high amount of insoluble fibre was fed.     

A comparative study of the metabolic effects of hypertrehalosemic hormone and 1,2,3,4,5,6-hexachlorocyclohexane (γ-HCH) in the American cockroach, Periplaneta americana

Several effects of hypertrehalosemic hormone (Peram-HTH) have been compared with the action of 1,2,3,4,5,6-hexachlorocyclohexane (γ-HCH) in the cockroach, Periplaneta americana. The data show that both agents stimulate respiration while maintaining an R.Q. of approximately 1. The action of γ-HCH differs from that of Peram-HTH-I in that it promotes oxidation of large amounts of soluble carbohydrate. Recent studies show that Peram-HTH-I has an equally potent stimulatory effect on lipid deposition in the fat body and on the release of trehalose from the same tissue. It is of interest that γ-HCH not only increases triacylglycerol accumulation in the fatγ body but that this effect is more pronounced if the γ-HCH is applied to the ventral surface of the mesothorax. γ-HCH also depleted whole body glycoprotein and glycolipid whereas Peram-HTH-I had no effect on glycoprotein but increased that of glycolipid. It is clear that γ-HCH causes complex disruptions to the metabolism of the insect, many of which are related to the release of hormones. The study supports the idea that certain actions of γ-HCH are mediated through the release of Peram-HTH-I.     

蝴蝶兰花芽诱导过程中碳水化合物在叶与腋芽中的分配变化

 研究了粉色蝴蝶兰（KM 833）在两个不同条件下处理（处理组：人工气候箱日/夜温25℃/20℃；对照组：温室大棚生长条件）过程中叶片和腋芽中碳水化合物在叶与腋芽中的分配变化。结果发现对照的蝴蝶兰新叶开始时面积增长较快，但最后的叶面积的大小基本相同，处理组的单位叶面积干样质量在15 d后超过对照组；处理组蝴蝶兰叶片还原糖含量在20 d达到1个小高峰后下降，在30 d后开始急剧上升,至50 d达到最大值(31.08 mg·g^-1DM)，对照组的蝴蝶兰叶片还原糖含量在整个试验期间则较为恒定且缓慢地增长，腋芽中的还原糖含量则随时间而下降；两种处理蝴蝶兰叶片的可溶性糖和淀粉含量均随着时间的进程而逐步升高，处理组的蝴蝶兰腋芽中的可溶性糖和淀粉含量则在处理15 d内有个快速增加后缓慢下降，对照组腋芽的三类碳水化合物在处理期间处于上升趋势。无论在叶还是腋芽中,诱导组的碳水化合物含量均高于对照组。