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1.
从27份深海沉积物中筛选到30株产淀粉酶细菌,并对其中的W7菌株的产酶条件及酶学性质进行了研究。对W7菌株进行16SrDNA序列分析表明该菌株属于盐单胞菌属(Halomonas)。其最适生长温度为25℃,能适应pH值7~13和盐度0~100的环境条件。该菌株可利用多种碳源,但只在淀粉存在的条件下产酶,可利用有机氮源和无机氮源,但有机氮源更能促进淀粉酶的产生。产酶的最适条件为:25℃,pH10,接种量2%,盐度50,150r/min摇床培养36~48h。粗酶液的最适作用温度为40℃,最适pH值为10。该菌具有反硝化和氨化活性。  相似文献   

2.
本文通过纳米ZnO(ZnO-NPs)对具有高效脱氮能力的异养硝化-好氧反硝化菌Halomonas sp. KGL1的短期暴露实验,探讨在不同作用浓度下(0,1,10,50 mg·L~(-1)) ZnO-NPs对菌株的生物胁迫效应。结果表明,ZnO-NPs破坏菌株Halomonas sp. KGL1的细胞膜完整性并改变其粘滞性,使菌株形态结构改变,菌体发生团聚;同时诱导该菌株细胞产生活性氧(Reactive Oxygen Species,ROS),对菌株细胞产生氧化胁迫,进一步损伤菌株细胞,抑制菌株的生长和脱氮能力,且ZnO-NPs浓度越高,该菌株受胁迫程度越强。不同浓度的ZnO-NPs对菌株Halomonas sp. KGL1的NH~+_4-N去除率无显著影响,而其NO~-_3-N、NO~-_2-N的去除效率显著降低。研究结果可为提高海水养殖废水等高盐含氮废水中脱氮菌株的抗ZnO-NPs胁迫能力的理论研究和实际应用提供科学依据。  相似文献   

3.
中国对虾体内1株益生菌的筛选与初步鉴定   总被引:1,自引:0,他引:1  
为给对虾专用益生菌制剂的研制与应用提供理论依据和基础数据,研究了从白斑病毒(WSSV) 耐过中国对虾(Fenneropenaeus chinensis)肠道中分离的1株海洋细菌B12的益生特性和安全性,并结合形态观察、生理生化特征和16S rDNA序列分析对菌株B12进行了分类鉴定.结果表明:菌株B12能抑制对虾致病性哈维氏弧菌 (Vibrio harveyi)和副溶血弧菌(V. parahaemolyticus)的生长,不分泌溶血素.对β-内酰胺类、头孢类、氨基糖苷类、喹诺酮类抗生素均敏感;对大环内酯类、四环素类抗生素均耐药;对糖肽类抗生素中度敏感.毒性试验表明菌株B12对中国对虾幼体没有明显毒副作用.该菌为革兰氏阴性可动杆菌,鞭毛极生,菌体大小为(0.5~0.6)×(1.1~1.2) μm,接触酶、氧化酶阳性,葡萄糖发酵产酸,能还原硝酸盐,产淀粉酶,不产明胶酶,不能利用丙二酸.16S rDNA的部分序列分析显示菌株B12与嗜盐单胞菌(Halomonas sp.)SB J85具有98.15%的相似性.形态观察、生理生化特征和16S rDNA序列分析证实B12为嗜盐单胞菌属(Halomonas sp.).  相似文献   

4.
一株海洋聚磷菌YSR-3的分离与鉴定   总被引:14,自引:1,他引:13  
采用平板分离法,从黄海海域分离到一株聚磷菌,编号为YSR-3,对其进行了部分生理生化特性以及分子特性的研究。结果表明,YSR-3菌体呈杆状,大小为3·5μm×1μm,革兰氏染色阴性,好氧生长;显微镜下观察能运动。最适培养条件为:氯化钠浓度3%,生长温度为24℃,起始pH值为6·5。该菌能在细胞内累积多磷酸盐形成异染粒。16SrDNA鉴定结果表明,YSR-3属于γ-变形菌纲、盐单胞菌属(Halomonas)。与盐单胞菌属中的其他已知种比较,YSR-3具有其特性:对氯霉素和卡那霉素敏感、淀粉水解呈阳性、反硝化和几丁质降解呈阴性、能将葡萄糖作为唯一碳源和能源。  相似文献   

5.
盐单胞菌属一新种的分离与鉴定   总被引:1,自引:0,他引:1       下载免费PDF全文
对即墨市大桥盐场的底泥样本进行微生物的可培养研究,分离出1株革兰氏阴性的中度嗜盐菌YC-SA28T.16SrRNA序列比对及系统发育分析结果表明.YCSA28T可能为γ-变形菌纲盐单胞菌属的新种,通过系统分类学研究发现,YCSA28T的16SrRNA序列与亲缘关系最近的盐单胞菌属模式菌株Halomonas ventos...  相似文献   

6.
以从海南三亚近海海水中采集的样品为研究对象,利用平板筛选法筛到一株产酯酶的中度嗜盐菌菌株LYG1-1。通过形态学、生理生化及16S rRNA序列分析,发现该菌株为革兰氏阴性菌,其最适生长温度为30℃,最适生长pH为7.5,最适NaCl浓度为10%。16S rRNA基因序列分析显示,菌株LYG1-1与Halomonas salina亲缘性最近,16S rRNA基因序列相似性为99.72%。在含10%NaCl的0.05mol·L-1Tris-HCl(pH 8.0)缓冲液中,45℃条件下作用,酶活性最高,40℃处理24h仍保持83%的活性。金属离子浓度为5mmol·L-1时,Ca2+、Mg2+对菌株LYG1-1酶活具有明显的激活作用,Hg2+表现出强烈的抑制作用。  相似文献   

7.
浒苔(Enteromorpha prolifera)生长及孢子释放的生态因子研究   总被引:26,自引:0,他引:26  
通过考察浒苔属浒苔藻体生长及孢子释放的生态因子条件,确定其各单因子的适应范围及最适范围.结果表明:浒苔藻体生长对盐度、温度、光照强度和酸碱度的适应范围分别为 16~40、10 ℃~30 ℃、>9 μmol/m2s、6~10,最适范围分别为 24~28、20 ℃~25 ℃、>18 μmol/m2s、8~9,在盐度、温度、光照强度和酸碱度分别为24、25 ℃、72 μmol/m2s、8 的条件下达到最大生长量;浒苔释放孢子对盐度、温度、光照强度和酸碱度的适应范围分别为 12~40、15 ℃~35 ℃、>9 μmol/m2s、6~10,最适范围分别为 28~40、20 ℃~35 ℃、>36 μmol/m2s、8~9,在盐度、温度、光照强度和酸碱度分别为32、35 ℃、144 μmol/m2s、9 的条件下达到最大释放量.浒苔藻体生长及孢子释放的各单因子适应范围基本相同,最适范围区别明显.  相似文献   

8.
对一株分离自深海热液口的超嗜热古菌(Thermococcus sp.HJ21)菌株进行了α-淀粉酶发酵条件的优化和酶学性质的研究.该菌株发酵9h后到达产酶高峰,产酶温度范围为60-90℃,其最适产酶温度为80℃.产酶pH范围为5.0-9.0,最适产酶pH为7.5.产酶NaCl浓度范围为0.5-4.0%,2.5%为最适宜NaCI浓度.糖原、淀粉、麦芽糖、酵母膏和蛋白胨促进产酶.该菌株产生的α-淀粉酶的分子量为51.4 kDa,酶的最适作用温度为95℃,在100℃仍有60%的酶活力.酶在90℃的半衰期为5 h,在100℃ 2 h仍有40%的残余酶活,酶的热稳定性不依赖Ca2+.酶的最适作用pH为5.0,pH 4.5仍有80%的酶活力,pH在5.5-7.0较稳定(80℃ 4 h).金属离子1 mmol/L的Mg2+、Co2+、Sr2+、Ba2+、K+、Na+对酶有激活作用,Cu2+、Pb2+、Hg2+、zn2+、Al3+对该酶均有抑制作用.  相似文献   

9.
对来自于南大西洋洋中脊(SMAR)的盲虾Rimicaris sp.虾鳃中的附生好氧菌及厌氧菌进行了富集培养,共分离得到14株低温好氧菌和2个稳定的厌氧富集菌群.通过对好氧菌的16S rDNA序列系统发育分析,发现14株低温分离菌株分别属于海源菌(Idiomarina)、海杆菌(Marinobacter)、涅斯捷连科氏菌(Nesterenkonia)、赤杆菌(Erythrobacter)、盐单胞菌(Halomonas)、交替单胞菌(Alteromonas)、嗜冷菌(Psychrobacter)、Mesonia8个属,其中9株属于变形菌门(2株属于α-变形菌纲,占总菌株数的14.3%;7株属于γ-变形菌纲,占总菌株数的50.0%).对2个厌氧富集菌群的16S rDNA文库的39个阳性克隆子进行分析,获得2种基因型,分别为γ-变形菌纲的产碱杆菌属(Alcaligenes)和β-变形菌纲的嗜麦芽寡营养单胞菌属(Stenotrophomonas).结果表明,南大西洋洋中脊盲虾虾鳃附生菌类型较为丰富,对于附生菌的研究能够更加全面的认识盲虾与附生菌之间的相互作用.  相似文献   

10.
褐藻酸降解酶的制备及其性质研究   总被引:6,自引:0,他引:6       下载免费PDF全文
通过培养褐藻酸降解菌交替单胞菌(Alteromonas sp.)菌株H-1使其产酶,研究了该酶的性质。结果表明,该菌在25℃培养72h时产酶量最高。褐藻酸酶作用的最适底物质量分数为1%~2%。最适pH值为7.5,最适反应温度为40℃,温度升高酶活力急剧下降。  相似文献   

11.
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.  相似文献   

12.
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.  相似文献   

13.
海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明:土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。  相似文献   

14.
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths.  相似文献   

15.
Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.  相似文献   

16.
17.
《海洋学报(英文版)》2014,(8):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,  相似文献   

18.
19.
This article presents a methodology developed to evaluate the instability of submarine slopes that extend over a large area. Special attention was paid to (1) the complex geometry (bathymetry) and the expanse of the slope, (2) the heterogeneity of the sediment, and (3) the distribution of the pore pressure. The safety factor was considered as a spatially varying quantity. The General Formulation (GLE, Fredlund and Krahn 1977), which fully satisfies equilibrium conditions, was used for evaluating the stability of the marine slope. The submarine slope failure, which occurred on 16 October 1979 during the construction of the new Nice airport, was studied in order to test the developed model. Geotechnical parameters were taken from experimental tests carried out by IFREMER on 19 cores extracted at different depths (from 27 m to 1300 m) (Cochonat, Bourillet, and Savoye, 1993; Mulder et al., 1994). Many scenarios were proposed in order to explain the cause of the Nice slope failure (Habib, 1994). In this article, two of those scenarios were tested. Simulation results are presented and discussed.  相似文献   

20.
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone.  相似文献   

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