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101.
S. L. Hsieh H. T. Chang C. H. Wu C. M. Kuo 《Aquaculture (Amsterdam, Netherlands)》2004,230(1-4):527-546
The stearoyl-CoA desaturase cDNA in tilapia (Oreochromis mossambicus) was cloned by RT-PCR and RACE, and it was compared with those in grass carp, common carp and milkfish. Nucleotide sequence analysis revealed that the full length of cDNA (1172 bp) clone encompasses 1008 bp open reading frame (ORF) encoding 336 amino acid residues. The deduced amino acid sequence shares 78–82% identity with the teleosts and 64–66% with mammals compared, and like these fish, the cloned tilapia stearoyl-CoA desaturase amino acid sequence conserves three histidine cluster motifs (one HXXXXH and two HXXHH), which functioned as non-heme iron binding sites, essential for stearoyl-CoA desaturase activity. RT-PCR and Northern blot analysis reveal that tilapia stearoyl-CoA desaturase is expressed only in liver, but the stearoyl-CoA desaturase expression in multiple tissues was observed in milkfish, grass carp and carp. Further, the hormonal regulation of stearoyl-CoA desaturase gene expression was investigated by a single injection of 17β-estradiol and testosterone. The results showed that the administration of 17β-estradiol to tilapia led to a greater increase in desaturase activity than testosterone, and higher doses of steroids produced greater increases in enzyme activity. The comparative RT-PCR analysis showed that the stearoyl-CoA desaturase mRNA level increased significantly in 17β-estradiol treated animals, especially in the groups receiving a single injection of 50 mg 17β-estradiol. This was reflected in the decrease in the saturated fatty acids and the increase in the monounsaturated fatty acids. The proportion of the polyunsaturated fatty acids was not affected. 相似文献
102.
捕虾桁拖网网囊网目的选择性研究 总被引:33,自引:2,他引:33
当网囊网目分别为40mm,45mm和50mm时,哈氏仿对虾的50%选择体长分别为85.88,90.26,95.32mm;中华管鞭虾的30%选择体长为87.58,88.09,92.56mm;鹰爪虾的50%选择丛长为85.04,85.96%,88.32mm。三种虾类的50%选择体长和网囊网目内径的线性回归方程为,哈氏仿对虾L0.5-48.03+0.94Me中华管鞭虾;L0.5=67.0+0.498Me 相似文献
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一品红不同品种叶片叶绿素荧光特性比较 总被引:7,自引:1,他引:6
利用叶绿素荧光技术测定了一品红4个品种‘金多利’、‘圣诞天使’、‘索诺拉飞雪’、‘旗帜’叶片光强依赖的叶绿素荧光特性。结果表明: ‘金多利’初始荧光( Fo ) 、最大荧光( Fm ) 和可变荧光( Fv ) 值极显著高于其它3个品种。在各个光强( PAR, 0~2 171μmol·m- 2 ·s- 1 ) 下, 表观电子传递速率( rETR) 、实际光化学效率(Yield) 和光化学淬灭( qP ) 的变化趋势一致, 均为‘金多利’ > ‘圣诞天使’ > ‘索诺拉飞雪’ > ‘旗帜’, 在高PAR下这种差异更明显。拟合参数最大潜在相对电子传递速率( rETRmax ) 、半饱和光强( Ik) 和光抑制参数(β) 也同rETR等具有一致变化。说明‘金多利’有较高的PSⅡ活性, 耐强光; 而‘旗帜’则光化学效率较弱, 高光强下易受光抑制。 相似文献
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106.
矸石是在煤炭生产过程中产生的固体废弃物。我国是煤炭生产和消费的大国,全国每年矸石排放量约1.7亿t,已形成矸石山1500余座,压占大量土地,污染环境。文章在分析辽西北矿区矸石废弃地立地生态特征及研究该地区造林适用原则基础上,对造林关键技术进行研究分析,提出相应栽植技术要点,对该地区矸石废弃地植被恢复、改善生态环境具有实际指导意义。 相似文献
107.
Wen-Ling Mou Shi-Ru Chen Zhen-Ting Wu Li-Hua Hu Ji-Ye Zhang Hong-Jie Chang Hang Zhou Ying Liu 《Journal of toxicologic pathology》2022,35(2):193
Liver fibrosis results from liver inflammation and progresses to liver cirrhosis or liver cancer. It is known that nonalcoholic liver disease is mediated by the Toll-like receptor 4 (TLR4)/myeloid differentiation factor-2 (MD-2)–tumor necrosis factor-alpha (TNF-α) signaling pathway. This study aimed to investigate whether alcoholic liver disease is also mediated by this pathway. To this end, we first established rat models of liver fibrosis by administering alcohol. Next, the rats were injected with anti-TLR4 and anti-MD-2 antibodies. Real Time Quantitative PCR (RT-qPCR) and Western blotting were used to detect the activation of the TLR4/MD-2–TNF-α signaling pathway and hepatic stellate cells (HSCs). Moreover, the expression of molecules related to liver fibrosis was estimated. The morphology of rat liver tissue was observed through hematoxylin–eosin staining and Masson staining. For in vitro studies, Kupffer cells (KCs) isolated from the liver were transfected with si-TLR4 and si-MD-2 and co-cultured with HSCs to determine the activity of HSCs. It was found that alcohol treatment activated the TLR4/MD-2–TNF-α signaling pathway and upregulated the molecules associated with liver fibrosis. However, inhibition of TLR4 and MD-2 partially reversed this trend. Notably, in vitro studies indicated that knockdown of TLR4 and MD-2 in KCs partially inhibited LPS-induced activation of KCs and HSCs. Overall, this study showed that alcohol induces liver fibrosis via the LPS-TLR4/MD-2–TNF-α signaling pathway. 相似文献
108.
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110.
施肥和密度对小麦产量及加工品质的影响 总被引:18,自引:6,他引:18
为了探讨提高产量和改善品质的合理栽培措施,试验采用不同氮肥和密度处理,研究其对产量和品质的影响,结果表明:基本苗为225万~450万/hm2时产量差异不显著,但均比150万/hm2基本苗处理显著提高了产量。施氮270 kg/hm2比135 kg/hm2显著提高了产量。不同基本苗处理对蛋白质含量和加工品质指标影响较小,但不同施氮量对各蛋白组分、总蛋白质含量及加工品质指标有显著影响,高氮处理比低氮处理显著提高了总蛋白质和各蛋白组分含量,并显著增加了沉淀值、湿面筋含量、干面筋含量、吸水率、形成时间和面包体积。结论认为:基本苗对产量影响较大,对品质影响较小,施氮处理对产量和品质均有重要影响,适当增施氮肥可以使籽粒产量、营养品质和加工品质同步提高。 相似文献