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991.
在4500~4800lux光照,26~28℃的培养条件下,从绿裸藻(Euglena viridis)水华中分离的优势菌种之一中性柠檬酸菌(Citrobacter intermedius)的分泌物对斜生栅藻(Scenedesmus obliquus)、粉核小球藻(Chlorella pyrenoidosa)、羊角月牙藻(Selenastrum capricormutum)、水华鱼腥藻(Anabaena flos-aquae)和易变鱼腥藻(Anabaena vqriabilis)的生长有促进作用;对银灰平裂藻(Merismopedia glauca)、莱茵衣藻(Chlamydononas reinhardii)和铜绿微囊藻(Microcystis aerugiuosa)的生长具有抑制作用.中性柠檬酸菌胞外分泌物能促进粉核小球藻细胞个体的长大,对其他藻类主要是影响细胞的大小.中性柠檬酸菌对不同藻类影响的差异对水华过程可能具有重要意义. 相似文献
992.
用Windows NT Server 4.0组成局域网及应用 总被引:1,自引:0,他引:1
WindowsNTServer4.0与Windows95具有相同的图形界面,对系统的管理和维护非常方便、直观。使用该系统很容易组成一个实用、高效的局域网,还能提供多种服务。如:DNS、E-mail、WWW等。 相似文献
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综述了土壤中重金属复合污染表征方法的研究进展,目的在于为农业生态环境中重金属污染的研究和防治提供参考 相似文献
995.
太白洋参化学成分的研究 总被引:1,自引:0,他引:1
对太白洋参中的脂肪酸、有机酸及15种化学元素进行了测定和分析。结果表明,太白洋参中不饱和脂肪酸含量占总脂肪酸的76.82%,且主要由亚麻酸、亚油酸和油酸组成;太白洋参中富含酒石酸、苹果酸、乙酸和柠檬酸4种有机酸及Mg,Ca,Fe,Zn,P5种化学元素,这些化学成分在人体生命运动中起着非常重要的作用 相似文献
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Characterization of microbial communities in intensive GIFT tilapia (Oreochromis niloticus) pond systems during the peak period of breeding 下载免费PDF全文
Jiazhang Chen Shunlong Meng Chao Song Liping Qiu Gengdong Hu Pao Xu 《Aquaculture Research》2017,48(2):459-472
Aquaculture pond is a complex ecosystem where the microorganisms in the sediments, in the animal intestinal tract and in water interact with each other to influence the water quality and health of aquatic animals. In order to understand the spatial distribution and relationship of microbial communities in intensively farmed genetically improved farmed tilapia (GIFT, Oreochromis niloticus), 454 high‐throughput pyrosequencing was applied to analyse the 16S rRNA gene of bacteria in intensive GIFT ponds in Wuxi City, Jiangsu Province, China. A total of 72 747 initial sequences were obtained from four depths of pond water, from tilapia large intestines and from pond sediment. The most common phylum in all samples was Proteobacteria, Actinobacteria and Cyanobacteria were the most abundant in water, Fusobacteria and Firmicutes in the large intestine and Chloroflexi in sediment samples. The sediment microbial community structure was comparatively similar to that of the tilapia large intestine. The microbial communities from different water depths were somewhat similar, especially the three most shallow samples, although the abundance of Actinobacteria gradually decreased with increased water depth. This data offer a preliminary exploration of the response mechanisms of the bacterial communities to aquafarming and contributes to the understanding of the status of bacterial communities of tilapia pond systems during the peak period of breeding from the aspect of their spatial distributions. 相似文献
999.
Rapid detection of SNPs in candidate genes regulating the growth of orange‐spotted grouper,Epinephelus coioides (Hamilton, 1822), using semiconductor sequencing 下载免费PDF全文
Liang Guo Junhong Xia Sen Yang Mingming Li Xinghan Chen Haoran Lin Zining Meng 《Aquaculture Research》2017,48(2):494-504
Orange‐spotted grouper (Epinephelus coioides) is one of the most important marine food species in Southeast Asia and China and has been cultured for decades. In this study, we fully utilized the limited capacity of semiconductor sequencing, the high efficiency of long‐range PCR for target enrichment and a non‐indexed pooling strategy to screen single‐nucleotide polymorphisms (SNPs) in a breeding population of orange‐spotted grouper. Forty‐one genomic DNA fragments, with a total length of approximately 180 kb, including 22 candidate genes that control growth, and from a DNA pool of 20 heaviest and 22 lightest individuals of the sampled population were successfully sequenced using an Ion Torrent Personal Genome Machine. 3 503 466 clear reads were produced with a length of 192 ± 56 bp, 86.8% of which were mapped to the reference with an average coverage depth of 2567‐fold and physical coverage of 98.8%. Finally, 1623 high‐quality SNPs were adopted. Compared with Sanger sequencing of three random common regions, the sensitivity and specificity of our approach were 39.4% and 100.0% respectively. A mutation located at the third position of the previously labelled start codon of growth hormone receptor type 1 invalidated the start codon. Furthermore, comparison of the frequencies of genotypes and alleles of this site between the two extreme groups, prediction of signal peptide and identification of conservative mRNA sequences suggested that the functional start codon is likely located at the position of another downstream in‐frame ATG in the mutant. These detected SNP markers will provide important tools for the selective breeding of orange‐spotted grouper. 相似文献
1000.
Yuanyuan Ren Haishen Wen Yun Li Jifang Li Feng He Meng Ni 《Fish physiology and biochemistry》2017,43(6):1707-1720
To investigate the correlation between lipid deposition variation and stocking density in Amur sturgeon (Acipenser schrenckii) and the possible physiological mechanism, fish were conducted in different stocking densities (LSD 5.5 kg/m3, MSD 8.0 kg/m3, and HSD 11.0 kg/m3) for 70 days and then the growth index, lipid content, lipase activities, and the mRNA expressions of lipid-related genes were examined. Results showed that fish subjected to higher stocking density presented lower final body weights (FBW), specific growth ratio (SGR), and gonad adipose tissue index (GAI) (P < 0.05). Lower lipid content was observed in the liver, gonad adipose tissue and muscle in sturgeons held in HSD group (P < 0.05). The serum concentrations of triglyceride (TG), total cholesterol (TC), and high-density lipoprotein cholesterol (HDL-C) decreased significantly with increasing stocking density, while no significant change was observed for low-density lipoprotein cholesterol (LDL-C). Furthermore, the cDNAs encoding lipoprotein lipase (LPL) and hepatic lipase (HL) were isolated in Amur sturgeon, respectively. The full-length LPL cDNA was composed of 1757 bp with an open reading frame of 501 amino acids, while the complete nucleotide sequences of HL covered 1747 bp encoding 499 amino acids. In the liver, the activities and mRNA levels of LPL were markedly lower in HSD group, which were consistent with the variation tendency of HL. Fish reared in HSD group also presented lower levels of activities and mRNA expression of LPL in the muscle and gonad. Moreover, the expressions of peroxisome proliferator-activated receptor α (PPARα) in both the liver and skeletal muscle were significantly upregulated in HSD group. Overall, the results indicated that high stocking density negatively affects growth performance and lipid deposition of Amur sturgeon to a certain extent. The downregulation of LPL and HL and the upregulation of PPARα may be responsible for the lower lipid distribution of Amur sturgeon in higher stocking density. 相似文献