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91.
92.
Ecotoxicity of three potentially toxic metals (PTM) (Cu, Zn, and Cr) in a slightly acidic sandy soil is tested using the soil respiration test (OECD‐217) in order to determine EC50 values for the carbon transformation activity of microorganisms. Addition of an organic amendment of Populus leaves is also crossed with metal spiking in order to investigate possible interaction with metal toxicity. Soil respiration is measured at day 1 and 28 after the soil spiking with the PTM to assess short‐term effects on soil microbial activity. Of the three metals tested, Cu shows the highest toxicity at the longest exposure times (day 28) and Zn shows a strong inhibitory effect in the short‐term (day 1), even though later toxicity diminish significantly. Cr is the least toxic studied PTM. Organic amendment outweighs any adverse effects of these metals, increasing soil respiration, even in the treatments with high doses of metals. 相似文献
93.
为了利用南极微生物资源、探索南极罗斯海区域可培养微生物多样性,利用传统平板培养法对中国第33次南极科学考察采自南极罗斯海6个站位的海洋沉积物样品进行了细菌、真菌的分离培养。经细菌16S rRNA、真菌ITS基因序列检测及系统发育分析,共获得5个属的36株细菌和6个属的29株真菌。其中嗜冷杆菌属为优势细菌类群,枝孢属为优势真菌类群。该结果表明南极罗斯海区域具有丰富的微生物多样性。细菌API 20 NE生理生化及真菌产胞外酶活性实验显示,分离得到的细菌和真菌绝大多数都有低温酶活性。研究结果为南极罗斯海区域可培养微生物的多样性认识和低温酶产生菌资源获取与开发利用提供了支撑。 相似文献
94.
D-乳酸及其酯是重要的手性药物中间体和手性化工产品。从南海深海芽孢杆菌Bacillus sp. SCSIO15029克隆到一个乙酰酯酶基因bae02030, 表达并鉴定该酶Bae02030的酶学性质。该酯酶的最适pH和最适温度分别为8.5和35℃, 其对多种有机溶剂和表面活性剂具有较好的耐受性。乙酰酯酶Bae02030能够通过水解拆分消旋乳酸甲酯来制备光学纯的D-乳酸甲酯。通过对拆分反应进行优化, 添加体积分数为60%的正庚烷能够改善乙酰酯酶Bae02030的光学选择性, 所制备的D-乳酸甲酯的对映体过量值(e.e.s)超过99%, 转化率(c)为56%。深海微生物来源的乙酰酯酶Bae02030作为生物催化剂在工业上制备手性药物中间体具有较好的应用潜力。 相似文献
95.
在大菱鲆(Scophthalmus maximus)工厂化养殖废水中接种繁茂膜海绵(Hymeniacidon perleve),并将繁茂膜海绵与大菱鲆同池养殖,研究繁茂膜海绵对大菱鲆工厂化养鱼水体微生物的净化作用。结果表明,接种量为7 mg/L繁茂膜海绵经过8、16、24、32、40、48 h对养鱼废水中细菌总数的清除率分别为23.18%、47.65%、66.09%、81.57%、93.80%、98.96%;对弧菌的清除率分别为48.61%、56.44%、78.13%、92.88%、97.10%、98.56%;对大肠杆菌的清除率分别为39.51%、41.90%、73.24%、92.29%、97.69%、99.14%,将繁茂膜海绵以7 mg/L的生物量与大菱鲆同池养殖24 h,水体中细菌总数、弧菌和大肠杆菌的清除率分别为61.38%、50.34%、93.47%。 相似文献
96.
97.
Surface snow samples of different altitudes and snow pit samples were collected from Glacier No.1 at the Urumqi River Head,
Tianshan. Denaturing gradient gel electrophoresis (DGGE) was used to examine the diversity and temporal-spatial characteristics
of eukaryotic microorganisms with different altitudes and depths. Results show that the eukaryotic microorganisms belong
to four kingdoms—Viridiplantae, Fungi, Amoebozoa, and Alveolata. Among them, algae (especially Chlamydomonadales)
were the dominant group. The diversity of eukaryotic microorganisms was negatively correlated with altitude and accumulation
time, but positively correlated with δ18O values. These results indicate that temperature is the main factor for the temporal-
spatial change of eukaryotic microorganisms, and the diversity of eukaryotic microorganisms could be an index for climate
and environmental change. 相似文献
98.
1Introduction The marine environment contains a complex va-riety of plants, animals and microorganisms. Owingto their unique adaptations to the habitat, these liv-ing creatures elaborate a wide diversity of naturalproducts with specific bioactivities, whi… 相似文献
99.
厌氧条件下,Cronobacter sakazakii以乙酸钠作为电子供体,针铁矿中Fe(Ⅲ)作为电子受体进行生命活动,其新陈代谢过程伴随Fe(Ⅲ)的还原。细菌增殖和稳定生长过程中不停还原针铁矿并大量累积Fe(Ⅱ);当细菌衰亡时,Fe(Ⅱ)的产生随之减缓;细菌的活动停止时,Fe(Ⅱ)不再积累并最终保持稳定。同步辐射XRD测试表明,微生物还原作用后针铁矿出现了一系列新衍射峰:4.8、6.03、6.13、6.84、7.7和11.4 峰,可能形成具层状结构的新物相。在XANES图谱中Fe主吸收峰向低能量方向移动1 eV,边前峰峰位中心向低能量方向移动且峰面积减小,表明Cronobacter sakazakii的异化Fe(Ⅲ)还原作用使针铁矿中Fe氧化态降低,矿物晶体结构发生了变化。 相似文献
100.
Ivan Gláucio Paulino-Lima Sérgio Pilling Eduardo Janot-Pacheco João Alexandre Ribeiro Gonçalves Barbosa Alvaro Costa Leitão 《Planetary and Space Science》2010,58(10):1180-1040
The radiation-resistant bacterium Deinococcus radiodurans was exposed to a simulated interplanetary UV radiation at the Brazilian Synchrotron Light Laboratory (LNLS). Bacterial samples were irradiated on different substrates to investigate the influence of surface relief on cell survival. The effects of cell multi-layers were also investigated. The ratio of viable microorganisms remained virtually the same (average 2%) for integrated doses from 1.2 to 12 kJ m−2, corresponding to 16 h of irradiation at most. The asymptotic profiles of the curves, clearly connected to a shielding effect provided by multi-layering cells on a cavitary substrate (carbon tape), means that the inactivation rate may not change significantly along extended periods of exposure to radiation. Such high survival rates reinforce the possibility of an interplanetary transfer of viable microbes. 相似文献