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1.
Cloning, expressing, and hemolysis of tdh, trh and tlh genes of Vibrio parahaemolyticus 总被引：1，自引：0，他引：1
Vibrio parahaemolyticus (VP) is one of the pathogenic vibrios endangering net-cage cultured Pseudosciaena crocea,Fennerpenaeus chinensis, and shellfish in coastal areas of China. Several types of hemolysins produced by Vp have been characterized as major virulence factors.They are thermostable direct hemolysin (TDH),TDH-related hemolysin (TRH) and thermolabile hemolysin (TLH). In this study, we cloned tdh, trh, and tlh genes from the genome DNA of VP by polymerase chain reaction (PCR).We ligated the three genes into prokaryotic expression vector pET-28a (+),and transformed the recombinant plasmids into Es-cherichia coli BL21 (DE3). The expression of recombinant proteins was induced by isopropyl-β-D-thiogalacto-pyranoside (IPTG). The recombinant proteins were expressed in a form of inclusion bodies and thus purified with Ni-NTA affinity chromatography. Western blotting results showed that recombinant proteins,TDH, TRH and TLH, could be recognized by rabbit anti-VP serum. The three purified proteins were renatured by gradient dialysis.The renatured proteins exhibited hemolytic activity except for TLH in the presence of phosphatidylcholine. These results not only are helpful for better understanding these genes’ functions under a single factor level, but also provide evidence for VP vaccine engineering. 相似文献
2.
Thirty-three species of marine algae belonging to Rhodophyta, Phaeophyta and Chlorophyta from the Fujian coast were examined for agglutinins with different animal and human erythrocytes. Protein extracts from 26 species were active against at least one type of the erythrocytes tested. There were 3 species (Grateloupia imbricata, lshigefoliacea and Entermorpha prolifera) whose extracts could agglutinate all the erythrocytes used. The lowest protein concentration required to produce erythrocyte agglutination varied remarkably, from 3.1μg/ml to 500μg/ml . The strongest activity was found in the agglutina-tion of rabbit erythrocytes by Gloiopeltis furcata extract. Inhibition assays performed with nine mono- and bisaccharides indicated that agglutinations of rabbit erythrocytes by extracts of 7 species were inhibited by one or more types of the sugars assayed. The agglutinating activity shown by extracts of most species wasnot affected when the test solution was heated to 90℃, but was lost at 95℃ - 100℃. A few extracts losttheir activity at 60 RS, 65 RS and 75 RS, respectively. 相似文献
3.
Cyanea nozakii Kishinouy e (C. nozakii), a giant cnidarian of the class Scyphomedusae, order Semaeostomeae and family Cyaneidae, is widely distributed in the East China Sea, the Yellow Sea and the Bohai Sea, and is abundant from late summer to early autumn. Venom produced by C. nozakii during mass agglomerations can contaminate seawater resulting in death of the halobios and seriously damage commercial fisheries. Swimmers and fishermen commonly suff er painful stings from this jellyfish, resulting in local edema, tingling, breathing difficulties, depressed blood pressure and even death. Such effects arise from the complex mixture of biologically active molecules that make up jellyfish venom. In the present study, the hemolytic activity of venom from tentacles of C. nozakii and factors aff ecting its activity were assayed. The HU50 ( defined as the amount of protein required to lyse 50 % of erythrocytes) of the venom against dove and chicken erythrocytes was 34 and 59 μg/mL, respectively. Carboxylmethyl chitosan and glycerol could increase hemolytic activity at concentrations greater than 0.06% and 0.2 mol/L, respectively. 相似文献
4.
Seasonal cycle is the most significant signals of topography and circulation in the Bohai Sea (BS)and Yellow Sea (YS) forced by prevailing monsoon and is still poorly understood due to lack of data in their interiors. In the present study, seasonal cycles of topography in the BS and YS and its relationship with atmospheric forcing and oceanic adjustment were examined and discussed using TOPEX/Poseidon and ERS-I/2 Sea Level Anomalies (SLA) data. Analyses revealed complicated seasonal cycles of topography composed mainly of 2 REOF modes, the winter-summer mode (WlM) and spring-autumn mode (SAM). The WlM with action center in the BS displayed peak and southward pressure gradient in July, and valley and northward pressure gradient in January, which is obviously the direct response to monsoon with about l-month response time. The SAM with action center in the western south YS displayed peak and northward pressure gradient in October and valley and southward pressure gradient in April. After the mature period of monsoon, the action center in the BS becam eweakened while that in the western south YS became strengthened because of regional convergence or divergence induced by seasonal variations of the Taiwan Warm Current and Yellow Sea Coastal Current. The direct response of topography to monsoon resulted in the WIM, while oceanic adjustment of topography played an important role in the forming of the SAM. 相似文献
5.
以黄颡鱼"红头病"致病菌——鮰爱德华菌(Edwardsiella ictaluri)A86作为实验菌株,通过十二烷基肌氨酸钠(Sarkosyl)抽提并结合超速离心的方法提取主要外膜蛋白(OMPs),SDS-PAGE图谱分析结果显示,OMPs主要有6条条带,相对分子质量分别为45 000、42 000、41 000、36 000、30 000和22 000。用A86 OMPs免疫新西兰大白兔,获得多克隆抗体22 mL,抗体效价为1∶20 480,抗体按照1∶2 560稀释时具有较高的特异性,仅与迟缓爱德华菌(E.tarda)、海豚链球菌(Streptococcus iniae)和创伤弧菌(Vibrio vulnificus)存在微弱的交叉反应,与鮰爱德华菌参考株及不同地区的分离株呈现特异性结合。多克隆抗体与OMPs的免疫印迹结果显示,主要有2条明显的免疫反应发色带,相对分子质量分别为36 000和30 000,且36 000蛋白染色最为明显。多克隆抗体与包括菌株A86在内的分离自南北方不同地区的10株鮰爱德华菌全菌免疫印迹试验发现,所有受检菌株反应结果相同,主要有4条明显的反应条带,相对分子质量分别为106 000、54 000、36 000和30 000,其中36 000和30 000两条蛋白带染色最深。因此,认为从黄颡鱼体内分离的鮰爱德华菌OMPs中36 000和30 000蛋白具有很好的免疫原性,36 000蛋白尤甚。 相似文献
6.
黄河源区拥有独特的生态系统和生物资源,是我国重要的江河水源涵养地和重要的生态屏障。近年来,放牧家畜数量的增加使该地区传统草地畜牧业面临过度放牧、草地退化、季节性失衡等发展难题。为科学掌握黄河源区放牧家畜的情况,本文以黄河源区的玛多县为研究区,应用无人机对玛多县放牧家畜（牦牛、藏羊和马）的数量和空间分布开展航拍调查。根据牦牛、藏羊和马的无人机图像解译标志库进行目视解译,采用5种方法估算玛多县放牧家畜的数量,利用选择指数分析家畜空间位置与环境因子的关系,结果表明：① 在冷季无人机航拍样带内,牦牛、藏羊和马的样带密度分别为4.12、7.34和0.06 只/km2。② 玛多县有牦牛7.08万头,藏羊10.22万只,马0.12万匹,经验证,估算牦牛、藏羊和马数量的误差分别为-0.93%、2.27%和-13.23%。③ 家畜对环境因子的选择倾向于坡度小于12°,草地覆盖度高于0.6,距居民点小于1 km,距水源小于 3 km,距公路大于3 km的区域。研究结果表明,无人机遥感技术在畜牧业方面有较大的应用潜力,为研究牧区放牧家畜的特征和草畜平衡情况提供新的思路。 相似文献
7.
以全鱼粉作为唯一蛋白源(D1),用豆粕替代10%、20%鱼粉(D2、D3),玉米蛋白粉替代10%鱼粉(D4),啤酒酵母替代10%鱼粉(D5),配制5组等氮等能饲料,每种饲料设置3个实验组,进行56 d的养殖实验。通过血液和组织涂(印)片、细胞染色和显微观察,研究人工培育的褐点石斑鱼幼鱼外周血液白细胞的分类组成,头肾、脾脏、体肾和肝脏等4种组织中各类血细胞的发生情况,以及不同蛋白源饲料对褐点石斑鱼血细胞发生的影响。结果表明:褐点石斑鱼外周血液中的白细胞由淋巴细胞(53.30%±4.66%)、血栓细胞(35.69%±3.85%)、嗜中性粒细胞(10.34%±3.14%)、单核细胞(0.28%±0.36%)、浆细胞(0.24%±0.34%)和嗜酸性粒细胞(0.15%±0.27%)组成;组织印迹片中,未成熟的红细胞、淋巴细胞和粒细胞主要在头肾印迹片中出现,未成熟的单核细胞主要在头肾和脾脏印迹片中出现,血栓细胞在肝脏印迹片中数量最多,推断褐点石斑鱼幼鱼主要的造血组织是头肾,其次是脾脏;在4种组织中均观察到浆细胞,在体肾印迹片中观察到嗜碱性粒细胞,在肝脏印迹片中观察到巨噬细胞,在头肾印迹片中还观察到巨大原红细胞。显微观察和数据统计分析的结果都表明,投喂5种蛋白源不同的配合饲料,未对褐点石斑鱼4种组织中血细胞的发生情况造成显著影响。 相似文献
8.
《山地科学学报》2019,(11)
Increasing populations of large carnivores are leading to tension and conflicts with livestock production, a situation that potentially might escalate.In Norway the objective of the large carnivore policy is two-folded: to ensure viable carnivore populations and to secure a sustainable grazing industry. The main instrument is zonation, with carnivore management zones(CMZs) prioritized for reproduction of the large carnivore species separated from other areas prioritized for grazing livestock. The objective of this paper is to describe current knowledge about the impact of the zoning management strategy on the grazing industry. This is done by documenting status and changes in sheep production, losses of livestock to predating carnivores,and the use of grazing areas inside and outside the CMZs. CMZs offering protection for lynx, wolverine,bear and wolf cover 55% of the Norwegian mainland.30% of the sheep and 50% of the Sami reindeer grazing areas are found inside the CMZs. Livestock(semi-domestic reindeer excluded) is using 59% of the available natural pasture areas outside the CMZs, but only 26% inside the CMZs. The lowest use of availablegrazing areas was found inside zones for wolves(12%)and brown bears(6%). Livestock in these zones are confined to fenced enclosures, mostly on the farm itself, or moved to pastures outside the management zone for summer grazing. Livestock losses increased in the affected regions during the period when carnivores were reestablished. Later, losses declined when CMZs were established and mitigation efforts were implemented in these zones. The bulk of sheep and reindeer killed by carnivores are now found in boundary areas within 50 km off the CMZs, where sheep are still grazing on open mountain and forest ranges. Therefore, instruments to protect livestock in areas close to the CMZs are also needed. The number of sheep declined inside the CMZs from 1999 to 2014,but increased outside the zones. The reduction in the absolute number of sheep in the CMZs is balanced by a similar increase outside, thus the total sheep production in Norway is maintained. We conclude that although of little consequence for the total food production in Norway, the economic and social impact of the large carnivore management strategy can be serious for local communities and individual farmers who are affected. There is a need for more exact carnivore population monitoring to quantify the carnivore pressure, better documentation of reindeer losses, and a clearer and stricter practicing of thezoning strategy. Increased involvement of social sciences is important in order to understand the human dimension of the carnivore conflicts. 相似文献
9.
A double-sided slope with high water content in sandy clay was considered under the action of seismic load. Its failure mode and dynamic response were investigated using a hydraulic servo shaking table test. The typical characteristic of failure mode and dynamic responses of the double-sided slope were analyzed. Experimental results show that slope failure undergoes a process of progressive deformation. The slope failure mode can be explained as creep sliding landslide. AFA (Amplification Factor of Acceleration) at the surface and inner parts of the slope shows an increasing trend with the increase of relative elevation. The relationship between AFA and EAA (Excitation Amplitude of Acceleration) is nonlinear. An empirical formula is proposed to describe preferably the relationship between AFA, relative elevation and dimensionless EAA. The AFA at the middle and upper parts of the slope increases apparently with increasing EFA (Excitation Frequency of Acceleration). 相似文献
10.
在持续降雨或开挖卸荷作用下, 土体的强度指标会发生劣化, 但现今采用的边坡稳定性计算大多直接将其视为一个常数。为接近真实的边坡失稳破坏模式, 基于瑞典条分法以及一阶线性应变软化机制, 提出了一种边坡渐进破坏分析新方法, 推导出应变软化型边坡极限平衡表达式, 并获得了各破坏进度下边坡的安全系数。通过对模拟算例进行分析, 证明了条分-软化法的可靠性, 且计算结果表明渐进破坏过程中安全系数不仅取决于边坡的破坏方式与强度参数, 还与岩土体的软化模量密切相关。同时, 通过与滑坡实际案例的对比验算, 证实其强度指标存在不同的衰减系数, 即黏聚力的衰减系数大于摩擦角。从理论到应用, 最终获得的条分-软化法, 不仅考虑了岩土体的强度劣化效应以及滑动面的渐进发展, 还能有效地服务于实际工程背景下边坡的稳定性分析, 可以为滑坡的预防与治理提供指导建议。 相似文献
11.
Muyingle is a new type of health food prepared from marine organisme. The mammotropic action ofMuyingte was investigated by studying its effect on mammary glands and pituitary glands of lactating miceand the survival rate of suckling mice. The results showed that the mammotropic action of Muyingle wasvery effective.The survival rates of suckling mice were 92.90% for the treated group and 0 for the controlgroup (p<0.01). The weights of mammary gland were 163±51.1mg/10g (weight of mouse)for the treatedgroup and 98.5±18.4 mg/10g for the control group (p<0.01). Histological examinations suggestal thatmammary glands from the treated group were at the secreting stages, while those from the control groupwere at the resting stages. Clinical tests also demonstrated that Muyingle was highly effective in promotinglactation and improving the quality of the puerpera's milk. The efficiency was up to 86.7%. 相似文献
12.
《山地科学学报》2020,17(6):1360-1373
The high mountains of northern Pakistan comprise the western section of the Hindu KushKarakoram-Himalayas(HKH) region of South and Central Asia. They are home to some rare and endangered species of fauna and flora which form an important link in the biodiversity of the region as a whole. Increasing population and changing life styles in recent decades have brought unprecedented pressures on the biodiversity of this region. Along with the government, the non-governmental organizations(NGOs) and communities have a crucial role to play in conserving biodiversity. In this regard,a number of undertakings to protect depleting species have been initiated by governmental and nongovernmental entities. These efforts are commendable and some have produced positive results, but many exist on a small scale and, with a few exceptions, are not self-sustaining. This paper reports on some of these initiatives of conserving big mammal species like the Astor markhor, Blue sheep,Himalayan brown bear, Himalayan ibex and Snow leopard, with the aim of collating and highlighting them, identifying gaps in conservation and suggesting a way forward so as to promote conservation projects on a larger and more sustainable basis. 相似文献
13.
In the present study, galactosylated chitosan (Gal-CS) was conjugated with methoxy poly(ethylene glycol) (mPEG) as a hydrophilic group. The structure of Gal-CS-mPEG polymer was characterized and the nanoparticles (NPs) were prepared using ironic gelation method. The study was designed to investigate the characteristics and functions of Gal-CS-mPEG NPs. The morphology of Gal-CS-mPEG NPs was observed by SEM and it was a compact and spherical shape. The size of the NPs was approximately 200 nm in diameter under the ideal process parameters. The interaction between Gal-CS-mPEG NPs and pDNA, and the protection of pDNA against DNase I and serum degradation by Gal-CS-mPEG NPs were evaluated. Agarose gel electrophoresis results showed that Gal-CS-mPEG NPs had strong interaction with pDNA at the weight ratio of 12:1, 4:1 and 2:1 and could protect pDNA from DNase I and serum degradation. Gal-CS-mPEG NPs exhibited high loading efficiency and sustainable in vitro release. The blood compatibility studies demonstrated that Gal-CS-mPEG NPs had superior compatibility with erythrocytes in terms of aggregation degree and hemolysis level. Gal-CS-mPEG NPs showed no cytotoxicity on L929 cells, which is a normal mouse connective tissue fibroblast, but showed inhibitory effects on the proliferation of Bel-7402 cells, which is a liver cancer cell line. In conclusion, Gal-CS-mPEG NP is a bio-safe and efficient gene carrier with potential application in gene delivery. 相似文献
14.
Precise structural identification of phospholipids in the microalga Nitzschia closterium has been established using ultra performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass
spectrometry (UPLC-ESI-Q-TOF-MS) for direct analysis of total lipid extracts. Mass spectrometry was performed in reflective
time-of-flight using electron spraying ionization in negative mode. Phospholipid molecular species identification was based
on the characteristic product ions and neutral loss yielded by different phospholipids under ESI-MS/MS mode. The molecular
species were confirmed by the carboxylate anions produced by phospholipids in negative mode; the regiospecificity of the two
acyl chains was determined from the ratio of sn-1 to sn-2 carboxylate anion abundances. As a result, 18 lipid molecular species were identified for the first time in this microalga,
comprising seven phosphatidylcholines (PC), two phosphatidylethanolamines (PE), two phosphatidylinositols (PI), and seven
phosphatidylglycerols (PG). Lipid standards of PC, PE, PI, and PG were added to the total lipids as internal standards for
semiquantitative analysis, revealing concentrations of phospholipids in this species between 0.09 and 3.37 nmol/mg. This method
can produce a full structural profile of intact phospholipid molecular species and can be used for study of the physiological
and ecological functions of lipids by monitoring their individual changes over time. 相似文献
15.
Empirical orthogonal function(EOF) analysis is performed on the field of the northern hemisphere geopotential height at 200-hPa using a 54-year(1958-2011) record of summer data on an interdecadal time scale.The first dominant mode,which shows smooth semi-hemispheric variation with maximum action centers in the western hemisphere in the mid-latitudes over the eastern Pacific,North America,and the North Atlantic,is related to global warming.The second mode,which has a pronounced tropical-extratropical alternating pattern with active centers located over the eastern hemisphere from Western Europe across East Asia to the western Pacific,has a close relationship with the Arctic Oscillation.Further analysis results indicate that the two dominant modes show good correlation with the Arctic sea ice concentration(SIC),with correlation coefficients between these two modes and the first two EOF modes of the Arctic SIC reaching 0.88 and 0.86,respectively. 相似文献
16.
张世亮 《广东海洋大学学报》1994,(1)
采用直流励磁装置、磁性磨料及工件共同构成磁加工系统。磁性磨料在磁场的作用下，对轴承内、外圈滚道以磁刷的形式进行研磨。由于磨料的可流动性，加工时既能满足对被加工表面粗糙度的加工要求，又能较好地保持工件原有的形位精度；且加工后在被加工表面形成一定的压应力，使工件的抗疲劳强度提高，使用寿命延长。 相似文献
17.
《中国海洋大学学报(英文版)》2015,(4)
Hydroxyethyl chitosan(HE-chitosan) is a water-soluble derivative of chitosan with many apparent biological properties. For example, it is non-toxic and rapidly biodegradable. Moreover, HE-chitosan has advantages in water-solubility, moisture retention and gelling property due to its hydroxyethyl group. However, the biocompatibility and biodegradability of this multifunctional derivative have rarely been documented although they are critical for its application in biomedical and clinical treatments. The purpose of this work was to evaluate the biosafety of HE-chitosan, and draw important clues for its diverse applications. HE-chitosan was synthesized and characterized its chemical structure with FTIR. Its molecular weight(MW) was determined by gel permeation chromatography(GPC), and its deacetylation degree(DD) was investigated through potentiometric analysis. The cytotoxicity of HE-chitosan on mouse fibroblast cell L929 was tested. The biocompatibility and biodegradability of HE-chitosan in rat and rabbit were evaluated. The FTIR results indicated that the hydroxyethyl groups were linked to C6 of chitosan. The GPC analysis confirmed that its Mw was about 90.01 k Da. It was also demonstrated that HE-chitosan had excellent biocompatibility and biodegradability in vivo and had no cytotoxicity on L929. These findings indicated that HE-chitosan can potentially be applied as a biomaterial in tissue engineering, drug delivery, and other biomedical fields. 相似文献
18.
The morphology and toxicity of Pseudo-nitzschia strain PP0201-01, isolated near the estuary of Changjiang （Yangtze） River in Year 2002 and tentatively identified as Pseudo-nitzschia pungens, were studied. The strain was identified morphologically as P. pungens using scanning electronic microscope （SEM）. The analytical results of LC-PDA （liquid chromatography with photodiode array detector）, LC-MS （liquid chromatography with mass detector）, and the toxicity data from mouse bioassay, showed that no domoic acid was produced by the strain. However, the mechanism of domoic acid production by Pseudo-nitzschia species is complicated. More works are needed to assess the toxic species and to evaluate the potential risk of amnesic shellfish poisoning （ASP） in China. 相似文献
19.
mODUCnONTheSOuthChinaSea(SCS)isasend-enclosedoceanbasinlocatednearthewesternPeripheryofthePacificOcean.SpreadingfIDmtheeqUatorto20"Nands~ngzonallaboutl5'inlooptUde,theSCSlocatesbetweenthesouthChinacoastandtheInaritha6continent,andissurroundedbyInanislandcountries.Duringwinter,S0UthwwhmedngcoldSUrges,mwhfiedbytheSST,affectthepressure,tempethe,andwindfieldsneartheInaritimecontinent,andsomeInayeveninIluencetheS0uthernHdrispheremonsoon(Davids0netal.,1983).msuniqUegeOpophyoftheSCS… 相似文献
20.
莫纯星 《广东海洋大学学报》2007,27(2):83-86
《儒林外史》是一部讽刺小说,主要运用对比讽刺,包括“鹤立鸡群”式、“言行相悖”式、“无独有偶”式、“前后矛盾”式、“自打嘴巴”式以及明比、暗比等讽刺。在作者的笔下,讽刺手法剥光了那些令人憎恶的封建文人、官僚豪绅、市井无赖等的外衣,露出了他们丑恶的灵魂,深刻地揭露了行将崩溃的封建制度的腐朽性,强烈地抨击了罪恶的科举制度。这种讽刺艺术在我国古代小说发展史上达到了顶峰。 相似文献