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971.
972.
Microbial conversions of unsaturated fatty acids often generate polyhydroxy fatty acids, giving them new properties such as higher viscosity and reactivity. A bacterial strain Pseudomonas aeruginosa (PR3) has been intensively studied to produce mono-, di-, and trihydroxy fatty acids from different 9-cis-monoenoic fatty acids such as oleic acid, ricinoleic acid, and palmitoleic acid. However, from the results and the postulated similar metabolic pathways involved in these transformations, it was assumed that the enzyme system involved in transformation of the monoenoic fatty acid by strain PR3 could utilize fatty acids with different chain lengths and locations of the double bond. In this study was used as a substrate for bioconversion by strain PR3 eicosenoic acid (C20:1, ω-9) containing a singular cis double bond at different positions from the carboxyl end as oleic acid, and it was confirmed that PR3 could produce a novel 9,12-dihydroxy-10(E)-eicosenoic acid (DED) with 6.2% yield from eicosenoic acid. The structure of DED was confirmed using GC-MS, FTIR, and NMR analyses. DED production was maximized at 72 h after the substrate was added to the 24 h culture. Some other nutritional factors were also studied for optimal production of DED. 相似文献
973.
华北平原高产粮区不同水氮管理下农田氮素的淋失特征 总被引:9,自引:2,他引:7
为了降低集约化种植制度下华北平原农田硝酸盐的淋失,该研究选择华北平原高产粮区,开展了为期2 a (2006-2008年)的田间试验,试验设计了2个灌溉处理(常规灌溉处理和基于土壤水分实时监控的优化灌溉处理)和2个施氮处理(传统施氮处理和优化施氮处理),利用张力计结合土壤溶液提取器对土体2 m处的水分和硝酸盐通量进行了监测和计算。研究结果显示,在相同施氮条件下,优化灌溉能够有效降低农田水分的渗漏量,渗漏量仅为传统灌溉渗漏量的50%左右。优化施氮能够有效降低2.1 m土体硝态氮含量,在相同灌溉条件下2.1 m土体硝态氮的残留量都在传统施氮的60%以下,而灌溉方式对硝态氮累积的影响不大。优化水氮管理相比传统水氮管理氮素的淋失量下降了60%,淋失率也下降了50%左右,粮食产量略有提高。 相似文献
974.
975.
本试验研究了不同生理状态下荷斯坦牛Ca、P表现消化率的变化规律.结果表明:生长期内不同生长阶段对奶牛Ca、P表观消化率影响显著(P<0.05),12月龄和24月龄奶牛Ca表观消化率显著高于18月龄(P<0.05);12月龄和24月龄奶牛P表现消化率极显著高于18月龄(P<0.01);泌乳2月与干奶期奶牛Ca、P表观消化... 相似文献
976.
Nhung Thi Nguyen Nguyen Xuan Bui Viet Linh Nguyen Van Khanh Nguyen Kazuhiro Kikuchi Hiep Thi Nguyen Hong Thi Nguyen Hoang Thinh Nguyen Quyen Van Dong Hoang Ha Chu Ngo Thi Kim Cuc Tamas Somfai 《Animal Science Journal》2020,91(1)
The Vietnamese Ban pig is a precious genetic resource that needs to be preserved. In vitro embryo production from in vitro matured (IVM) oocytes is an important tool for the utilization of cryopreserved porcine sperm. The aim of this study was to compare two media for the IVM of Ban pig oocytes. Immature oocytes were subjected to IVM either in a non‐defined (TCM‐199 + pig follicular fluid) or in a defined base medium (POM + epidermal growth factor). At the end of IVM, the oocytes were in vitro fertilized (IVF) with frozen Ban sperm. Ten hours after IVF, the oocytes were either subjected to orcein staining to check fertilization and maturation status or cultured in vitro for 7 days. There was no difference between the two IVM media in terms of percentages of oocyte maturation and blastocyst production. However, the percentage of male pronuclear formation after IVF and the total cell numbers in blastocysts were higher with the defined system. Zygotes obtained by the two IVM systems survived vitrification at similar rates. In conclusion, the two IVM systems were both effective for the production of Ban pig embryos; however, better embryo quality was achieved with the defined one. 相似文献
977.
菊花花瓣培养不定芽的形成及植株再生 总被引:2,自引:0,他引:2
侯喜林 《南京农业大学学报》1990,13(3):42-47
一次培养诱导菊花花瓣形成不定芽,以 MS+IAA10mg/L+6BA10mg/L+KT0.1mg/L 培养基为好。培养45天的芽分化率为68%~80%;平均每个发芽块产生的芽数是4.7~8.6个。用花瓣的基部组织进行培养,芽分化率(95%)显著高于中部(70%)和上部(60%)。不同接种方向对菊花花瓣不定芽形成无显著影响。菊花花瓣组织培养的效果在不同品种间差异极显著,形成不定芽能力的强弱顺序为白色>黄色>红色>粉红色。 相似文献
978.
脱毒甘薯增产性能研究 总被引:1,自引:0,他引:1
对脱毒甘薯徐薯18、北京553研究表明,脱毒薯与普通对照著相比具有地上部营养生长旺盛、地下部结薯早、薯块膨大速度快、薯皮色泽鲜艳、光滑、商品率高的特点。产量结果表明,甘薯脱毒能显著地提高产量,增产幅度达36%~133%。 相似文献
979.
Thinh Tuan Chu Per Madsen Elise Norberg Lei Wang Danye Marois John Henshall Just Jensen 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2020,137(2):245-259
A multivariate model was developed and used to estimate genetic parameters of body weight (BW) at 1–6 weeks of age of broilers raised in a commercial environment. The development of model was based on the predictive ability of breeding values evaluated from a cross-validation procedure that relied on half-sib correlation. The multivariate model accounted for heterogeneous variances between sexes through standardization applied to male and female BWs differently. It was found that the direct additive genetic, permanent environmental maternal and residual variances for BW increased drastically as broilers aged. The drastic increase in variances over weeks of age was mainly due to scaling effects. The ratio of the permanent environmental maternal variance to phenotypic variance decreased gradually with increasing age. Heritability of BW traits ranged from 0.28 to 0.33 at different weeks of age. The direct genetic effects on consecutive weekly BWs had high genetic correlations (0.85–0.99), but the genetic correlations between early and late BWs were low (0.32–0.57). The difference in variance components between sexes increased with increasing age. In conclusion, the permanent environmental maternal effect on broiler chicken BW decreased with increasing age from weeks 1 to 6. Potential bias of the model that considered identical variances for sexes could be reduced when heterogeneous variances between sexes are accounted for in the model. 相似文献