排序方式： 共有12条查询结果，搜索用时 125 毫秒
1.
郭忠文 《中国海洋大学学报(自然科学版)》1996,(3)
给出一种适合各种DOS版本和各种机型的微机硬盘安全管理方法。不仅可以预防已知或未知的计算机病毒，而且可对上机人员的权限进行统一分级管理，以防止硬盘重要系统信息的损坏，从而提高公用微机系统的可靠性。 相似文献
2.
We isolated 4 Norwalk-like viruses (NLVs) contaminated oysters from 33 Chinese oysters collected from local commer-cial sources of Shandong Province. After amplification of the RNA-dependent RNA polymerase (RdRp) region of NLVs genomes with RT-PCR, the open reading frame 1 (ORF1) of the RdRp was sequenced and subjected to multiple-sequence alignment. The re-suits showed that NLVs in the four isolates belong to genogroup Ⅱ. The sequence comparison showed that the similarity between four Chinese oyster isolates were higher than 99.0%, which indicated that NLVs prevalent in close areas have high homogeneity in genome sequences. In addition, the most conserved sequences between diverse NLVs were used to design primers and TaqMan probes, then the real-time quantitative PCR assay was performed. According to the standard curve of GII NLVs, the original amounts (copies) of NLVs in positive patient's fecal isolate, positive Japanese oyster isolate, and the Chinese oyster isolate were 8.9×108, 1.25×108 and 4.7×101 respectively. The detecting limit of NLVs was 1×101 copies. This study will be helpful for routine diagnosis of NLVs pathogens in foods and thus for avoiding food poisoning in the future. 相似文献
3.
Ballast water is a potential source of invasive species, including viruses that target a variety of hosts. We sampled ballast during two trans-Pacific voyages and analyzed the efficacy of mid-oceanic exchange in reducing virus-like particle (VLP) abundance. Exchange did not significantly reduce virus abundance during the first voyage (P = 0.874), whereas it reduced viral abundance 3.9-fold from 1.8 × 107 to 0.47 × 107 VLP mL−1 during the second voyage (P < 0.0001). Despite the impact of exchange during the second voyage, virus abundances were not significantly different between exchanged and unexchanged tanks upon arrival in Canada (P = 0.363) and Canadian port water samples (P = 0.502). Regressions between environmental parameters and VLP abundance uncovered negative correlations between salinity and viral abundance during one, and dissolved oxygen and viral abundance during the second voyage. In summary, ballast tanks are highly variable with respect to total virus abundance, and the efficacy of exchange requires investigation into the dynamics of specific viruses. 相似文献
4.
ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｒｅｃｅｎｔｙｅａｒｓ’ｒａｐｉｄｄｅｖｅｌｏｐｍｅｎｔｏｆｔｈｅｍａｒｉｎｅｆｉｓｈｃｕｌｔｕｒｅｉｎｄｕｓｔｒｙｉｎＣｈｉｎａｈａｓｂｒｏｕｇｈｔａｂｏｕｔｐｒｏｌｉｆｅｒａｔｉｏｎｏｆｖｉｒａｌｄｉｓｅａｓｅｓｉｎｔｈｅｉｎｄｕｓｔｒｙａｓｓｈｏｗｎｂｙｔｈｅｎｏｔａｂｌｙｆｒｅｑｕｅｎｔｏｃｃｕｒｒｅｎｃｅｏｆｄｉｓｅａｓｅｓｏｒｄｅａｔｈｓｏｆｔｈｅｍａｒｉｃｕｌｔｕｒｅｄｆｉｓｈ .Ｅｌｅｃｔｒｏｎｍｉｃｒｏｓｃｏｐｅｅｘａｍｉｎａｔｉｏｎｏｆｔｈｅａｆｆ… 相似文献
5.
This paper presents a review of the past decade's highlights of research on the isolation and characterisation of particulate
organic matter (POM) in the world's oceans. The emphasis is on chemical studies but, in keeping with the growing interdisciplinary
nature of marine science, advances in other disciplines are also discussed, particularly those in biological sciences. Increasing
evidence for the importance of picoplankton, bacteria and viruses as POM constituents is highlighted, including the recent
recognition of large populations of autotrophic bacteria able to harvest light for energy. The transport of POM to bottom
waters was thought to be largely confined to large, rapidly sinking faecal pellets. However, recent studies have highlighted
the importance of organic aggregates and flocs formed by diatoms such as Rhizosolenia and other microalgae. Ascending particles have also been discovered, many of which are lipid-rich. Several studies have shown
that resuspension of bottom sediments and lateral advection of material from continental shelves can lead to anomalously high
particle fluxes measured in sediment traps moored in deep water. Many new approaches for characterizing POM have emerged,
such as pyrolysis gas chromatography-mass spectrometry and direct temperature-resolved mass spectrometry for analysis of higher
molecular weight materials and biopolymers. Lipid biomarker techniques have also advanced, exciting new possibilities being
raised by the ability to measure stable and radioactive carbon isotopes for individual compounds. The techniques of molecular
biology, such as the polymerase chain reaction (PCR), are being increasingly applied to provide complementary information
to more conventional microscopy and flow cytometry on the identity of organisms in the sea. The combination of these techniques
with advanced chemical analysis methods promises to greatly increase our knowledge of the origins, transport and fate of organic
matter in the oceans.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
中国重点海水浴场中粪肠球菌和主要肠道病毒的调查研究 总被引：1，自引：0，他引：1
本文调查了中国十大典型海水浴场,旨在监测人类肠道病毒在海水浴场的发生情况,并且找出表面海水中肠道病毒的存在与传统的粪便污染指示物一粪大肠菌群是否存在关系,如果存在,是什么关系。分别采用常规的平板计数法和RT-PCR技术对粪大肠菌群和人类致病性的主要肠道病毒（甲肝病毒、轮状病毒、脊髓灰质炎病毒）进行了检测。结果显示,在2... 相似文献
7.
《Sedimentology》2018,65(4):1213-1245
In a modern peritidal microbial mat from Qatar, both biomediated carbonates and Mg‐rich clay minerals (palygorskite) were identified. The mat, ca 5 cm thick, shows a clear lamination reflecting different microbial communities. The initial precipitates within the top millimetres of the mat are composed of Ca–Mg–Si–Al–S amorphous nanoparticles (few tens of nanometres) that replace the ultrastructure of extracellular polymeric substances. The extracellular polymeric substances are enriched in the same cations and act as a substrate for mineral nucleation. Successively, crystallites of palygorskite fibres associated with carbonate nanocrystals develop, commonly surrounding bacterial bodies. Micron‐sized crystals of low‐Mg calcite are the most common precipitates, together with subordinate aragonite, very high‐Mg calcite/dolomite and ankerite. Pyrite nanocrystals and framboids are present in the deeper layers of the mat. Calcite crystallites form conical structures, circular to triangular/hexagonal in cross‐section, evolving to crystals with rhombohedral terminations; some crystallite bundles develop into dumb‐bell and stellate forms. Spheroidal organo‐mineral structures are also common within the mat. Nanospheres, a few tens of nanometres in diameter, occur attached to coccoid bacteria and within their cells; these are interpreted as permineralized viruses and could be significant as nuclei for crystallite‐crystal precipitation. Microspheres, 1 to 10 μm in diameter, result from intracellular permineralization within bacteria or the mineralization of the bacteria themselves. Carbonates and clay minerals are commonly aggregated to form peloids, tens of microns in size, surrounded by residual organic matter. Magnesium silicate and carbonate precipitation are likely to have been driven by pH – saturation index – redox changes within the mat, related to microenvironmental chemical changes induced by the microbes – extracellular polymeric substances – viruses and their degradation. 相似文献
8.
利用流式细胞仪计数微型浮游生物的方法 总被引：2，自引：0，他引：2
微型浮游生物(细胞粒径20μm)在水生生态系统的物质循环和能量流动中起着重要的作用,对其丰度的准确测定是进一步研究微型浮游生物在不同水生生态系统中作用的重要基础.相对于传统的显微镜检测技术,流式细胞术不仅具有分析速度快、灵敏度和准确度高等优点,而且可以同时测量单个细胞的多个生理参数.不同类型微型浮游生物流式细胞术的应用原理是不同的.对于自养型浮游藻类,主要根据藻体内色素的自发荧光对其进行分辨和计数;而对于异养型细菌、原生动物及浮游病毒等,还需借助外源荧光染料对细胞核酸染色后再进行分析.目前流式细胞术已成为浮游藻类和异养细菌丰度检测的常规方法,但是,由于原生动物具有更大的细胞体积且在自然水体中丰度较低;而浮游病毒粒径又太小,甚至低于光源激发波长,因此流式细胞术应用一直受到限制,直到近10年来才有相关报道.本文对运用流式细胞术计数浮游藻类、浮游细菌、原生动物和浮游病毒的具体原理、方法和进展进行综述,并对流式细胞仪在未来水生微生物学领域的应用进行展望. 相似文献
9.
病毒与细菌统称为微生物。病毒与细菌之害是生物生存遭遇到的最大的灾害,不仅在人类社会历史上留下了深重灾难,而且在地球生物演化史上也是大灭绝的重要推手。虽然病毒和细菌难以形成实体化石,但却以一种特殊的分子化石成为了侦探地质时期生物大灭绝的神针。本文以地球微生物学为指导,以蓝细菌和绿硫细菌分子化石为例,综合有关研究成果,解读了微生物学、病毒和细菌以及微生物岩的有关知识,帮助人们认识地球生物演化史上二次重要的大灭绝事件。本文还从人类演化过程中的农业革命,阐明了人菌共生关系及带来的启示。 相似文献
10.
A. A. Fincham 《新西兰海洋与淡水研究杂志》2013,47(4):655-662
The tidal swimming rhythm of the New Zealand rocky shore isopod Exosphaeroma obtusum (Dana) is described. Peak swimming was on the ebb tide about 2.5 h after high water; the peak in the dark period was 6–8 times greater in amplitude than the daytime peak. Positive thigmotaxis was shown at all other times. The rhythm period in continuous darkness (free‐running period) was greater than tidal periodicity, and there was a semi‐lunar swimming pattern with peaks at the first and third quarters of the moon. Rheotropic experiments showed that changes in water flow did not initiate the swimming rhythm. The work was compared with the infaunal species Pseudaega punctala and the northern Eurydice pulchra. It was concluded that infaunal species rely more on endogenous control of the swimming rhythm because of their isolation, when buried, from exogenous Zeitgeber. 相似文献