蛋氨酸锌螯合物中的锌在山羊代谢规律的研究

将１０头体重为９ｋｇ左右的健康浏阳黑公山羊分成两组,在代谢笼内个体饲喂,分别喂以含＾６５Ｚｎ蛋氨酸Ｚｎ（＾６５ＺｎＭｅｔ）和＾６５Ｚｎ硫酸锌（＾６５ＺｎＳＯ４）的饲粮,以比较研究蛋氨酸锌螯合物中的Ｚｎ在山羊体内的代谢规律结果表明,＾６５ＺｎＭｅｔ组在粪中排出＾６５Ｚｎ的浓度低于＾６５ＺｎＳＯ４组,在饲喂＾６５ＺｎＭｅｔ螯合物３ｄ期间Ｚｎ的表观吸收为４９．１２％,显著地高于＾６５ＺｎＺｎＳＯ４ｘｅｇ     

四种抗脂肪肝物质降低草鱼肝胰脏脂质积累的替代关系

采用１１种添加不同水平的蛋氨酸（Ｍｅｔ）,胆碱（Ｃｈ）甜菜碱（Ｂｅｔ）和大豆卵磷脂（Ｌｅｃ）的饲料饲养初始体重约１５ｇ的草鱼,研究了它们降低草鱼肝胰脏脂质积累的相互替代关系,１１种饲料中这四种物质的含量分别为（％）：（１）１．１Ｍｅｔ０．０８Ｃｈ,（２）１．１Ｍｅｔ０．３３Ｃｈ,（３）１．３Ｍｅｔ０．２３Ｃｈ,（４）１．５Ｍｅｔ０．１３Ｃｈ,（５）１．３Ｍｅｔ０．１３Ｃｈ,（６）１．３Ｍｅｔ０．１     

刺五加在大鼠实验性肝癌诱发过程中作用的探讨

目的探讨大鼠实验性肝癌发病中刺五加对肌体免疫功能和抗氧化酶活性的影响。方法４６只ＳＤ雄性大鼠被随机分成对照组（喂普通饲料）、３－甲基４－双甲氨基偶氮苯（３－Ｍｅ－ＤＡＢ）组（喂含０．０６％３Ｍｅ－ＤＡＢ饲料 １０周）和刺五加组（饲喂同 ３－Ｍｅ－ＤＡＢ外、另加入刺五加 ４．５ｇ／ｋｇ饲料,用常规方法检测全血谷光甘肽过氧化物酶（ＧＳＨ－ＰＸ）、血清超氧化物歧化酶（ＳＯＤ）活性和丙二醛（ＭＤＡ）含量,用微量化学发光造检测吞噬细胞活性（ＰＭＮ－ＣＬ）。结果１．ＰＭＮ－ＣＬ检测峰值、积分值和吞噬细胞指数,３－ＭｅＤＡＢ组较正常组和刺五加组均有显著升高（Ｐ＜０．０５和Ｐ＜０．０１）２．全血ＧＳＨ－ＰＸ活性、ＳＯＤ活性,刺五加组较３－ＭｅＤＡＢ组均有显著升高（Ｐ＜０．０５）。ＭＤＡ含量刺五加组和３－ＭｅＤＡＢ组均较正常组升高（均Ｐ＜０．０５）。结论刺五加在大鼠实验性肝癌诱发过程中有提高抗氧化酶活性和对抗致癌剂引起的机体中性粒细胞吞噬功能代偿性增高的作用。     

外源^65Zn进入土壤后的扩散及存在形态

利用６５Ｚｎ示踪和化学连续分级技术研究了外源Ｚｎ在褐土中的存在形态。结果表明交换态Ｚｎ（ＥＸ－Ｚｎ）和碳酸盐结合态Ｚｎ（ＣＡＲＢ－Ｚｎ）含量约占土壤总Ｚｎ量的６７－７２％．Ｚｎ投加量增加,土壤Ｚｎ的强度因数增大．反之,Ｚｎ的矿物形态增高．土壤水分４％和１００％时,土壤中Ｚｎ的扩散系数Ｄ分别是７．９×１０－８和６．６×１０－６ｃｍ２·ｓ－１．土壤水分含量在３０％和７０％时,Ｚｎ在施入点的平均停留时间分别是９ｄ和４ｄ．Ｚｎ的扩散程度（σ２）也随之从０增大到０．３７１．     

金葡菌及其L型感染荷瘤小鼠肿瘤内及非荷瘤小鼠肝脏内MDA和SOD的研究

用Ｐｙｒｏｇａｌｏｌ－ＮＢＴ等方法测定并分析荷瘤感染组,荷瘤非感染组及金葡菌及其Ｌ型感染组小鼠肿瘤或肝脏内超氧化歧酶（ＳＯＤ）和丙二醛（ＭＤＡ）含量对小鼠生存的影响。结果发现荷瘤伴感染组小鼠的平均存活天数明显短于荷瘤非感染组及正常对照组,Ｐ＜０．０５。,共中１６．７％荷瘤伴感染组小鼠同时伴有自发性肿瘤。金葡菌及其Ｌ型感染组２３．３％引起自发性肿瘤。金葡菌及其Ｌ型感染组及荷瘤伴感染组小鼠肿瘤和肝脏内ＭＤＡ含量明显高于荷瘤非感染组,Ｐ＜０．０５～０．０１。９８．７％荷瘤组小鼠肿瘤内ＳＯＤ含量极少或为零。金葡菌及其Ｌ型感染组与正常对照组小鼠肝内ＳＯＤ有明显差异,Ｐ＜０．０５。提示感染可能使小鼠体内ＳＯＤ量减少,ＭＤＡ量升高是引起小鼠发性肿瘤发生的重要原因之一。     

黑曲霉生产β-葡萄糖苷酶发酵条件的研究产

经多项式回归分析,研究了不同浓度Ｎ 源、Ｃ 源、无机盐等对酶产量的影响,确定出最佳培养基配方为：麸皮４ ．９ ％ ,（ＮＨ４）２ＳＯ４ ０ ．４ ％ ,ＫＨ２ＰＯ４ ０ ．２９ ％ ,ＣａＣｌ２ ０ ．０５ ％ ,ＭｇＳＯ４·７Ｈ２Ｏ０ ．０４ ％ ,ＦｅＳＯ４·７Ｈ２ Ｏ５ｍｇ·Ｌ－ １ ,ＺｎＣｌ２ １ ．４ｍｇ·Ｌ－ １ ,０ ．２ ％ 油酸钠．并对培养温度、时间、培养基初始ｐＨ、通气量、接种量、接种方式等培养条件进行优化,使黑曲霉生产β葡萄糖苷酶的产量由１７Ｕ·ｍｌ－ １ 增至２１ ．３Ｕ·ｍｌ－ １ ．     

米根霉发酵生产L-乳酸

报道了Ｌ－乳酸菌株的分离与筛选,探讨了不同碳源、氮源、通气量、温度等发酵条件对产Ｌ－乳酸的影响,从７８株米根霉中筛选出１３株产Ｌ－乳酸较高的菌株,其中米根霉（Ｒｈｉｚｏｐｕｓ ｏｒｙｚａｅ）Ｒｓ９２８产Ｌ－乳酸最高,产酸最稳定。试验结果表明,该菌株最适发酵培养组成（％）：淀粉水解糖１６,ＭｇＳＯ４ ０．０８,ＫＨ２ＰＯ４ ０．０５,ＺｎＳＯ４ ０．０１,ＣａＣＯ３ ７,ｐＨ自然。在６０ｔ发酵罐中,     

黑曲霉生产β—葡萄糖苷酶发酵条件的研究

经多项式回归分析,研究了不同浓度Ｎ源、Ｃ源、无机盐等对酶产量的影响,确定出最佳培养基配方为：麸皮４．９％,（ＮＨ４）２ＳＯ４０．４％,ＫＨ２ＰＯ４０．２９％,ＣａＣｌ２０．０５％,ＭｇＳＯ４·７Ｈ２Ｏ０．０４％,ＦｅＳＯ４·７５ｍｇ·Ｌ＾－ＺｎＣｌ２１．４ｍｇ·Ｌ＾－,０．２％油酸钠。并对培养温度１时间、培养基初妈ｐＨ、通气量、接种量、接种方式等培养条件进行优化,使黑曲霉生产β－葡萄糖苷酶的产量由     

CCK-8对癫痫发作大鼠脑内SOD和MDA的影响

目的和方法：采用核团微量注射、光化学分析等实验方法,观察大鼠脑内ＳＯＤ和ＭＤＡ在ＣＣＫ－８调节癫痫发作中的变化。结果：①与下沉大鼠比较,遗传性听源性癫痫易感大鼠皮层、海马、下丘脑及垂体内ＳＯＤＦ活性、ＭＤＡ含量无显著差异（Ｐ＞０．０５）;②大鼠癫痫发作后,上述区域内ＳＯＤ活性明显降低（Ｐ＜０．０５）,而ＭＤＡ含量明显增加（Ｐ＜０．０５）,若癫痫发作次数增加,该变化愈显著（Ｐ＜０．０１）;③大鼠海马     

玫瑰海棠的组织培养及快速繁殖

１植物名称玫瑰海棠（Ｂｅｇｏｎｎｉａ　ｍａｎｎｉｉ）。２材料类别幼芽、叶片。３培养条件以ＭＳ为基本培养基。诱导丛生芽培养基：（１）ＭＳ＋ＫＴ１．０ｍｐ·Ｌ－１（单位下同）＋ＮＡＡ０．１。丛生芽增殖培养基：（２）ＭＳ＋ＫＴ１．０＋ＮＡＡ０．０５;（３）ＭＳ＋６－ＢＡ０．５＋ＮＡＡ０．０５。诱导生根培养基：（４）１／２ＭＳ＋ＮＡＡ０．２。上述培养基均加３％蔗糖,０．８％琼脂,ｐＨ５．８。培养温度（２６±２）℃,光照度约为２０００ｌｘ,光照１４ｈ·ｄ－１。４生长与分化情况４．１无菌材料的获得将玫瑰海棠…     

Equivalent uptake of organic and inorganic zinc by monkey kidney fibroblasts, human intestinal epithelial cells, or perfused mouse intestine

Zinc (Zn) is recognized as an essential nutrient, and is added as a supplement to animal and human diets. There are claims that zinc methionine (ZnMet) forms a stable complex that is preferentially transported into tissues, and this has contributed to uncertainty about conflicting reports on the bioavailability of various Zn compounds. This study evaluated the cellular and intestinal uptake of inorganic and organic forms of Zn. Steady-state uptake of⁶⁵Zn by human intestine epithelial cells, and monkey kidney fibroblasts was not significantly different with zinc chloride (ZnCl₂), ZnMet, or zinc propionate (ZnProp) (P > 0.05). Uptake of⁶⁵Zn from zinc chelated with EDTA was significantly lower (P < 0.01). In live mice,⁶⁵Zn uptake by perfused intestine and deposition in intestine and liver showed no significant difference between ZnCl₂ and ZnMet. Equimolar [⁶⁵Zn]methionine and zinc[³⁵S]methionine were prepared according to a patented method that yields “ complexed” Zn. Cellular uptake of the radiolabeled methionine was <0.1% of the radiolabeled Zn from these complexes, indicating separate uptake of the Zn and methionine. Gel filtration did not distinguish between⁶⁵Zn in ZnCl₂, ZnProp, or reagent ZnMet, though feed-grade ZnMet containing >10% protein did give a higher-mol-wt form of⁶⁵Zn. Results of this study show equivalent uptake of Zn from inorganic and organic compounds, and support recent feed trials on Zn bioavailability.     

Maternal Zinc Supplementation Improves Spatial Memory in Rat Pups

A large body of evidence supports an opinion that adequate dietary zinc is essential for prenatal and postnatal brain development. Behavioural effects of maternal supplementation with ZnSO(4) were analysed in rat pups with the Morris water task performance, a hole board and a T-maze. Wistar females during pregnancy and lactation received a drinking water solution of ZnSO(4) at doses of 16 mg/kg (group Zn16) or 32 mg/kg (group Zn32). Behavioural tests were conducted on the 4-week-old male rat pups. Zinc concentration in the serum, hippocampus and prefrontal cortex of offsprings was determined by means of atomic absorption techniques. The Newman-Keuls multiple comparison test revealed an increase of climbing in the Zn16 group in comparison to the control group (Con) and the Zn32 group during the hole board test. ANOVA for repeated measures showed a significant memory improvement in both supplemented groups compared to the control in the probe trial on day 5 of the water maze test. ZnSO(4) treatment significantly elevated zinc levels in the rat serum. Follow-up data on brain content of zinc in the hippocampus revealed significant differences between the groups and in supplemented groups correlated with crossings above the original platform position. These findings suggest that pre- and postnatal zinc supplementation may improve cognitive development in rats.     

Change in apparent and true absorption and retention of dietary zinc with age in rats

Two groups of 16 rats each were fed the same diet with 12.9 ppm Zn. Nine days after each animal was injected with⁶⁵Zn for assessing fecal zinc of endogenous origin, zinc intake and excretion were determined for a six-day period at the age of about five (group I) and nine (II) weeks. At mean growth rates of 5.1 and 5.2 g/day, food consumption per gram of gain was 2.01 g in group I vs 2.86 g in II. Overall, zinc retention amounted to 21 vs 25 μg Zn/g of gain. Apparent absorption averaged 92 vs 74% of Zn intake (132 vs 189 μg/day), while true absorption averaged 98 vs 92%. It was concluded that endogenous fecal zinc excretion was limited to the indispensable loss (F _em) in group I (7 μg/day), while it exceeded this minimum loss in group II (33 μg/day). True retention, which reflected total zinc utilization (true absorption times metabolic efficiency), was derived from apparent absorption plusF _em (11 μg/day for group II according to the greater metabolic body size of the rats). It averaged 98% of Zn intake in group I vs 80% in group II. The mean metabolic efficiency was 100% vs 87%. The conclusion was that these marked differences between age groups in utilizing the dietary zinc reflected the efficient homeostatic adjustments in absorption and endogenous excretion of zinc to the respective zinc supply status.     

Altered Uptake and Biological Half-Lives of 65Zn on Arsenic Exposure—Modulation by Zinc Treatment

The present study revealed the effects of zinc on the biokinetics of (65)Zn in rats following arsenic intoxication. The animals were segregated into four groups: group I--untreated controls, group II--arsenic treated (100 ppm as NaAsO(2) in drinking water), group III--zinc treated (227 mg ZnSO(4) per liter drinking water), and group IV--arsenic?+?zinc treated. Each rat was injected intraperitoneally with 1.85 MBq radioactivity of (65)Zn following 3 months of different treatments, and the radioactivity was determined using a suitably shielded scintillation counter. Arsenic treatment showed a significant increase in the fast component (Tb(1)) of the biological half-life of (65)Zn in liver, which remained unaltered in the whole body. Furthermore, arsenic treatment decreased significantly the slow component (Tb(2)) in the whole body, which remained unchanged in the liver. However, zinc supplementation to arsenic-treated rats normalized Tb(1) in the liver, but caused no change in Tb(2) in the whole body. Furthermore, the uptake values of (65)Zn were significantly increased in the liver, brain, kidney, and intestine following arsenic treatment, and the values in the liver and brain were decreased by zinc. Hence, zinc plays a significant role in regulating the biokinetics of (65)Zn in the liver and the whole body of arsenic-intoxicated rats.     

Absorption,endogenous excretion,and balance of zinc in growing rats on diets with various sugars replacing starch

The effect of partially replacing starch for various sugars on the apparent and true absorption, endogenous excretion, and balance of zinc was investigated in a study with growing rats. Six groups of five or six animals with an initial live weight of 39.4 +/- 2.7 g were fed diets that had the same Zn content (22 mg/kg), but differed in the sugar content: 1. Starch only (56%); 2. Glucose (15%); 3. Fructose (15%); 4. Sucrose (30%); 5. Galactose (15%); and 6. Lactose (30%). At the start of a 15-d fecal and urinary collection period, each animal was given an intramuscular injection of 380 kBq 65Zn for estimating endogenous Zn excretion by isotope dilution. The ratio of the specific activity of fecal Zn (after 12 d) to that of urinary Zn (after 9 d) was applied to reflect the ratio of endogenous to total fecal Zn collected from day 10 to 15. This ratio averaged 0.59, without significant differences among treatments. For this period, apparent and true absorption averaged 87.1 and 94.7% of Zn intake, respectively, and did not significantly differ among diets. Urinary excretion of 65Zn and of stable zinc by the galactose-fed rats was markedly higher than that by the other animals. Their Zn balance was, per unit weight gain, comparable with that of the other groups (30.7 vs 28.2 to 30.2 micrograms/g).     

Effects of zinc and influence of Acremonium lolii on growth parameters, chlorophyll a fluorescence and antioxidant enzyme activities of ryegrass (Lolium perenne L. cv Apollo)

The effects of zinc on growth, mineral content, chlorophyll a fluorescence, and detoxifying enzyme activity (ascorbate peroxidase (APX), EC 1.11.1.11; superoxide dismutase (SOD), EC 1.15.1.1) of ryegrass infected or not by Acremonium lolii, and treated with nutrient solution containing 0-50 mM ZnSO(4) were studied. The introduction of zinc induces stress with a decrease in growth at 1, 5 and 10 mM ZnSO(4) and a cessation of growth at 50 mM ZnSO(4), in ryegrass plants infected by A. lolii or not. This decrease in growth may be due to an accumulation of zinc in leaves. Nevertheless, symbiotic plants showed higher values in tiller number, an advantage conferred by the fungus. After 24 d of Zn exposure, leaf fresh weights and leaf water content were lower in plants growing with Zn in the culture medium and no advantage was conferred by the fungus to its host. An increase in Zn supply resulted in a decrease of the Ca, K, Mg, and Cu content of the leaves, a reduction in the quantum yield of electron flow throughout photosystem II (DeltaF/F(1)(m))and a lowering of the efficiency of photosynthetic energy conversion (F(v)/F(m)), compared to control plants. To counter this zinc stress, detoxifying enzymes APX and SOD increased (100%) when Zn reached the value of 50 mM in the nutrient solution. At 10 mM ZnSO(4), the presence of the fungus in the plant led to an increase in the threshold toxicity of plants to zinc by a diminution of APX activity.     

Antioxidant effect of zinc and zinc-metallothionein in the acute cytotoxicity of hydrogen peroxide in Ehrlich ascites tumour cells

This study was concerned with the role of zinc (Zn) and zinc-metallothionein (Zn-MT) in oxidative stress. Hydrogen peroxide-induced oxidative injury was examined in Ehrlich ascites tumour cells isolated from control host mice, mice pretreated with 10 mg/kg ZnSO4 (i.p.) to increase cellular Zn/Zn-MT levels, and mice exposed to Zn-deficient diet to reduce the cellular Zn/Zn-MT levels. The results of the present study showed that Ehrlich cells with seven-fold differences in Zn-MT concentrations could be obtained by manipulating the Zn status of host mice and that high Zn and Zn-MT levels can make Ehrlich cells more resistant to H2O2-induced oxidative injury (cell viability, lipid peroxidation, [Ca2+]i) while cells with reduced Zn/Zn-MT levels were more susceptible to this treatment. H2O2 treatment resulted in oxidation of MT thiolate groups and loss of its metal binding capacity with translocation of Zn released from oxidized MT to other cellular sites. Preincubation of Ehrlich cells with ZnSO4 in vitro also conferred some degree of resistance to H2O2 toxicity, suggesting the inherent antioxidative property of Zn ions. These data suggested that Zn-MT can be considered as an antioxidant by virtue of its thiolate groups and its Zn ions that are released in the presence of oxidative stress.     

Increased methionine synthetase activity in zinc-deficient rat liver

To study the effect of zinc deficiency on folate metabolism, three groups of male Sprague-Dawley rats (zinc deficient (ZD), restricted-fed (RF + Zn), and ad libitum-fed control (control] were given a semipurified 25% egg white protein diet. The ZD group received less than 10.3 nmol zinc/g of diet, while the RF + Zn and control groups were given 1620 nmol zinc/g of diet. After 6-7 weeks of feeding, severe zinc deficiency developed in ZD rats. Hepatic methionine synthetase activity was increased in the ZD group compared to both the RF + Zn and control groups, but hepatic 5,10-CH2-H4folate reductase activity was similar in all groups. This increased methionine synthetase activity found in zinc-deficient rats might induce secondary alterations in folate metabolism. These changes include significantly lowered plasma folate levels, decreased 5-CH3-H4folate in liver, and increased rates of histidine and formate oxidation. The latter two findings suggest that the available non-5-CH3-H4folate is increased in zinc deficiency.     

Morphological and physiological characteristics of rapeseed plants regenerated in vitro from thin cell layers in the presence of zinc

Phytoremediation offers owners and managers of metal-contaminated sites an innovative and cost-effective option to address recalcitrant environmental contamination. The use of plants to restore or stabilize contaminated sites, known as phytoremediation, takes advantage of the natural abilities of plants to take up, accumulate or store metals. This includes the use of plants that tolerate and accumulate metals at high levels for phytoextraction and the use of plants growing under conditions that are toxic to other plants, for preventing, for example, soil erosion (phytostabilisation). Rapeseed (Brassica napus L.) was shown to be able to accumulate substantial amounts of metals combined with high biomass. Brassica napus was therefore selected for heavy metal (HM) tolerance and accumulation through in vitro selection. A selective pressure applied during the neoformation process from transversal thin cell layers (tTCLs) allowed us to select tolerant cells and tissues. Toxic metals (such as Zn) were added to the culture media in order to select zinc-tolerant plants. Exerting a selective pressure during tTCLs regeneration aimed at selecting plants with exceptional zinc tolerance and/or accumulating capacity. The morphological and physicochemical characteristics of regenerated plants cultivated in greenhouse appeared to depend very significantly on the concentration of ZnSO(4) applied during the neoformation process. Plants regenerated in the presence of ZnSO(4) at 100 microM exhibited a greater size and a higher biomass together with flowering precocity. The contents of zinc, chlorophyll, and proline were modified in the regenerated plants. Pre-treatment with an excess of ZnSO(4) (>500 microM) was responsible for a percentage of tTCLs intolerance above 96%. With lower Zn concentrations (100-250 microM), the survival rates (33-15%) were higher.