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21.
为了研究西太平洋黑潮源区不同深度沉积物中古菌群落结构的多样性,应用16S rDNA文库技术,对IMAGES XIV航次采集的岩芯MD06-3047进行基因文库的构建和分析,得到260个克隆,经分析处理后得到56个OTUs(Operational Taxonomic Units).基于16S rRNA序列的同源性比较,绘制系统进化树,进行统计学分析.研究结果显示,西太平洋黑潮源区的本哈姆高原(Benham Rise)沉积物中有丰富多样的古菌群落,在1m内的沉积物中分布着9种古菌类群.古菌序列归属于泉古菌(Crenarchaeota)和广古菌(Euryarchaeota),并以泉古菌为主(占总序列的91.5%).其中,泉古菌包含MGI、MBG-B、MCG和UCII-b 4个类群,并且主要由MGI构成(占总序列的40.8%),而广古菌包含MBG-D、SAGMEG、DHVEG、MBG-E和VAL Ⅲ 5个类群,各类群所占总序列比例均较低(占总序列的0.4%~5.4%之间).研究结果对于理解西太平洋黑潮源区沉积物中古菌多样性有重要意义,并为今后研究古菌群落与环境之间的关系提供科学依据. 相似文献
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23.
海带具有异型世代交替,其配子体在单独分离培养时可进行营养生长,形成无性繁殖系(克隆)。本文简要回顾了海带配子体克隆技术研究与应用的历程,综述海带配子体克隆在海带种质资源保存、海带生理和遗传学研究及海带育种和苗种繁育中的应用现状。 相似文献
24.
边坡地变形,具有高度复杂的非线性演化特征。将BP神经网络和免疫克隆算法改进并集成结合,提出一种新型的仿生智能方法,即免疫克隆神经网络。并利用其强大的非线性拟合能力,对边坡进行变形位移的预测。结果表明,此方法拥有较高的预测精度,为边坡变形位移的预测提供了行之有效的途径,从而为边坡稳定性判别和滑坡预报提供了可靠的分析依据。 相似文献
25.
Amplified fragment length polymorphism (AFLP) technique was used to analyze the fingerprinting of four successive generations
ofFenneropenaeus chinensis to reveal their disease-resistance traits. Some loci showed quite different genetic frequencies due to artificial selection,
which implied that these fragments were putative markers related to the disease-resistance trait. We developed a simple and
effective method to further characterize these AFLP fragments. Specific AFLP bands were cut directly from polyacrylamide gels,
re-amplified, cloned and sequenced. Eight putative genetic markers were sequenced and their sizes ranged from 63 to 209 bp.
The sequences were submitted to dbGSS (database of Genome Sequence Survey); and the BLAST analysis showed low similarity to
the function genes, indicating these markers were tightly linked to a disease-resistance trait but were not functional genes.
This research was supported by special funds from the National Key Basic Research Program (G1999012007) and the National High-Tech
Research and Development Program of China (863 Program. 2001AA620105). 相似文献
26.
When cultured under certain environmental conditions (25°C, light intensity 80 μmol/m2·s, LD 12/12, in enriched seawater medium with 7×10−4 mol/L NO3−N, 1.56×10−4 mol/L, PO4−P and supplements of other elements like Mn, Fe, I, etc.), male and female gametophytes ofU. pinnatifida kept growing vegetatively and propagated fast at average daily fresh weight increase rate of about 20%. The empirical formulaG
m=G
o·3m was established to estimate the output of vegetative gametophytes. Vigorous vegetative gametophyte cells began to form reproductive
structures (oogonium and spermatangium, when the temperature was lower than 25°C and other environmental factors were kept
optimal. The sufficient supply of gametophyte cells provided enough seeds for raisingUndaria sporelings on production scale. Controlled cross-breeding experiments using selected male and female gametophyte clones which
increase their cell number by mitosis instead of meiosis were also carried out in vitro. Juvenile sporophytes from the cross-breeding
had almost the same length and width increase rates as those of the control. The fact that vegetative gametophytes can be
purposely selected, propagated quickly, cross-bred, with the resulting sporophytes having almost the same characteristics
leads to a new way to select desiredUndaria strains for long time use without losing the desired economic characteristics.
Contribution No. 2696 from the Institute of Oceanology, Chinese Academy of Sciences.
Supported by National Natural Science Foundation of China. 相似文献
27.
采用基于16S r DNA克隆文库的非培养方法和传统培养方法相结合的手段,对南极欺骗岛土壤细菌群落结构及多样性进行了初步分析。对来自16S r DNA克隆文库的118个阳性克隆进行测序和序列比对,结果显示细菌来自放线菌门(Actinobacteria)、变形杆菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)3大门的39个操作分离单元(OTU),其中优势菌群为放线菌门和变形杆菌门,分别占65.25%和28.81%。放线菌门的主要优势属为鱼孢菌属(Sporichthya)、类诺卡式氏菌属(Nocardioides)、束缚菌属(Conexibacter)、Gaiella和节杆菌属(Arthrobacter)。变形杆菌门的主要优势属为鞘氨醇单胞菌属(Sphingomonas)、硫杆菌属(Thiobacillus)、寡养单胞菌属(Stenotrophomonas)和热单胞菌属(Thermomonas)。采用6种培养基对细菌进行培养和分离,共得到57株菌,来自放线菌门、变形杆菌门、拟杆菌门和厚壁菌门4大门的13个OTU,其中优势菌群为放线菌门和变形杆菌门,分别占57.89%和31.58%。优势属是放线菌门的节杆菌属(Arthrobacter)、雷夫松氏菌属(Leifsonia)和变形杆菌门的假单胞菌属(Pseudomonas)。本论文为研究欺骗岛土壤细菌多样性以及有益菌种资源的开发和利用奠定了基础。 相似文献
28.
Complementary (secondary) metabolites in a soft coral: sex-specific variability, inter-clonal variability, and competition 总被引:2,自引:0,他引:2
Sex‐specific interactions involving competition for space between the dioecious alcyonacean soft coral Sarcophyton glaucum and the scleractinian coral Acropora robusta were assessed experimentally on Bald Rock, central region of the Great Barrier Reef. To examine this, plus inter‐clonal responses, one male colony of S. glaucum, known to produce sarcophytoxide as its predominant complementary (secondary) metabolite, was sectioned, producing 10 clones. The same was done for a female colony. These two sets of clones were then relocated to grids and placed in contact with Acropora clones. Relocated and non‐relocated controls were also monitored. High levels of tissue necrosis were observed in the hard coral under contact conditions with both the male and female clones after 20 days. The development of a protective polysaccharide layer in the alcyonacean was also observed. Differences observed in the concentrations of complementary metabolites within the two different S. glaucum colonies were related to sex. Both under competition and non‐competition conditions, females exhibited significantly higher concentrations of sarcophytoxide than males, and this increased with time. Fatty ester concentration was also higher in females than males, varying significantly through time, and falling dramatically just after spawning. Fatty ester concentrations decreased linearly through time in the male clones. When involved in competition for space, females possessed higher concentrations of fatty esters than males, both at the site of contact and in non‐contact sites, again, decreasing after spawning. No significant changes in sarcophytoxide levels were noted in the parental colonies, but such changes were observed in fatty esters, with the female producing higher concentrations until after spawning. The use of these two variates in the form of a ratio (sarcophytoxide concentration:fatty ester concentration) yielded a variable Rho (ρ) which was a more sensitive indicator of biochemical change than either of its components alone. These two sets of compounds appeared to have a negative association through time and varied highly significantly between sexes. The diterpene sarcophytoxide may be considered an allelopathic or stress metabolite, while the lipids act as energy storage metabolites. 相似文献
29.
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