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1.
九孔鲍褐藻酸酶、琼脂酶及纤维素酶的提取纯化 总被引：8，自引：1，他引：8
采用（NH4）2SO4分段盐析和葡聚糖凝胶SephadexG-100柱层析纯化技术，从九孔鲍Haliotis diversicolor supertexta内脏器官中提取纯化褐藻酸酶、琼脂酶及纤维素酶，结果表明，在（NH4）2SO4分段盐析纯化中，褐藻酸酶和纤维素酶的最适分离饱和度为60%，而琼脂酶为70%，分段盐析的提纯倍数为（以粗酶提取液为参照）褐藻酸酶13.3 ,琼脂酶8.7和纤维素酶10.9。葡聚糖凝胶SephadexG-100层析分离过程中，褐藻酸酶，琼脂酶和纤维素酶的比活力高峰分别出现在洗脱液的64，48和80ml处，提纯倍数分别为褐藻酸酶80.9，琼脂酶68.0及纤维素酶15.2，上述提纯方法的研究结果将为这3种酶性质的进一步研究以及作为工具酶制剂产品的开发提供了工艺技术基础。 相似文献
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3.
A total of 117 agar-decomposing cultures were isolated from coastal seawater around Qingdao,China.The phenotypic and agarolytic features of an agarolytic isolate,QM38,were investigated.The strain was gram negative,strictly aerobic,curved rod and polar flagellum.On the basis of several phenotypic characters,biochemical and morphological characters and phylogenetic analysis of the gene coding for the 16S rRNA,the strain was identified as Agarivorans albus strain QM38.This strain can liquefy the agar on the solid agar plate.An excellular agarase activity was determined in liquid culture.The enzyme exhibited maximal activity at 40℃,pH 7.6.Its activity was greatly affected by different concentrations of agarose.The highest activity 32 U/ml was achieved in the culture supernatant.The hydrolytic product was analyzed by fluorophore-assisted carbohydrate electrophoresis (FACE).After complete hydrolysis of agarose,a series of agaro-oligosaccharides were produced.The main products of the enzymes were oligosaccharides in the degree of polymerization (DP) of 2,4,6 and 8.Three genes agaD01,agaD02 and agaD03,encoding β-agarases,had been cloned from genomic DNA of Agarivorans albus strain QM38.The open reading frame of agaD01,consisted of 2 988 bp,and shared 95.5%-98.9% identity to the β-agarase genes of some strains of Vibrio and Agarivorans.Gene agaD02 comprised 2 868 bp and encoded a 955-amino-acid protein.It showed 97.4% and 98.7% identity to the β-agarase genes of strain Vibrio sp.PO-303 and strain Vibrio sp.JT0107,respectively.Only partial sequence of agaD03 gene has been cloned.It showed 96.5% identity to β-agarase gene (agaB) of Pseudoalteromonas sp.CY24,and shared 96.8% identity to β-agarase-c gene of Vibrio sp.PO-303. 相似文献
4.
消化酶活力能够反映刺参对不同营养成分的消化能力。当某一反应条件发生改变时,消化酶的活力大小就会发生变化,因此研究不同因子对消化酶活力的影响对于了解消化酶的性质具有重要的意义。温度和pH是影响消化酶活力的最重要的反应条件。本文中作者应用酶学分析研究了温度和pH对剌参前肠和中肠各种消化酶活力的影响。蛋白酶活力测定采用福林-酚法,脂肪酶活力测定采用水解法,淀粉酶活力和纤维素酶活力测定采用水杨酸显色法。实验结果表明,反应温度和反应pH对刺参前肠和中肠中的消化酶活力具有显著影响(P<0.05)。前肠和中肠中蛋白酶活力均在反应温度为50℃时达到最大值,前肠和中肠中脂肪酶和纤维素酶均在反应温度为40℃时达到最大值,而前肠和中肠中淀粉酶最适反应温度分别为40℃和30℃。刺参前肠蛋白酶活力在酸性环境下较中肠高,且在反应pH为5.0—5.8之间酶活力相对稳定,而中肠蛋白酶活力在碱性环境下较前肠高,且在反应pH为7.0—8.6之间酶活力相对稳定;刺参前肠脂肪酶活力随着pH的升高出现两个相对稳定的峰值,分别为4.2—5.0和6.2—7.0区间,中肠脂肪酶活力在pH为3.8时达到最大值,而在pH超过9.0明显失活:剌参前肠和中肠淀粉酶活力在pH变化时表现出相似的变化趋势,在反应pH为6.6—7.4之间酶活力较高且相对稳定;剌参前肠和中肠中纤维素酶活力在pH变化时反应不一致,前肠淀粉酶在反应pH为6.2—7.4之间酶活力较高且相对稳定,中肠纤维素酶活力在反应pH为5.4—7.0之间酶活力较高且相对稳定。此外,通过比较四种消化酶比活力值的大小,可以看出剌参蛋白酶活力最高,其次为纤维素酶和淀粉酶活力,而脂肪酶活力最低。 相似文献
5.
从微泡菌属AG1（Microbulbifer sp. AG1）克隆得到1302 bp大小的琼胶酶基因，该基因编码产物为一个成熟蛋白（413个氨基酸残基）外加一个信号肽（20个残基）。将不含信号肽片段的琼胶酶在E. coli BL21 （DE3）中进行了异源表达和纯化。使用琼脂糖作为底物，该重组琼胶酶的最适反应温度和pH分别为60℃和7.5。该重组酶表现出优良的热稳定性，在50℃和60℃下处理1 h，重组琼胶酶仍能分别保持67%和19%的残余酶活力。除了SDS，重组琼胶酶对于其他测试的抑制剂、去垢剂和尿素变性剂有着较好的抗性。利用薄层色谱和以对硝基苯-α/β-D-吡喃半乳糖苷为底物的酶活力分析结果表明，该重组琼胶酶为β型琼胶酶，它水解琼脂糖的主要终产物为新琼四糖，而且不同聚合度的酶解产物具有抗氧化活性。 相似文献
6.
厦门沿岸海域杂色鲍中产琼胶酶菌株的筛选及其酶学性质的研究 总被引：1，自引：0，他引：1
琼胶酶在食品工业中的多糖降解中有着重要的作用,其经济价值日益凸显,从海洋生物中筛选琼胶酶菌株是获得琼胶酶的一种重要途径.从厦门沿岸海域养殖杂色鲍鱼体内分离得到5株产高效琼胶酶的菌株,其中最高的酶活力达到133.5 U/dm3.经16S rRNA序列分析表明这5株菌株分别属于弧菌属（Vibrio）和假交替单胞菌属（Pseudoa lteromonas）.采用DNS法对这些菌株所产的琼胶酶进行酶学性质研究,结果显示这些酶的最适作用温度均为50℃,最适作用pH值为7.0;Na＋可使A017菌株所产的琼胶酶酶活力提高5倍,Fe2＋对A007、A008、A010、A021菌株所产的琼胶酶酶活力有明显的抑制作用. 相似文献
7.
This work investigates the alkaline phosphatase activity in a littoral marine ecosystem (Toulon Bay and Le Niel Bay, France) in order to study its biochemical characteristics with respect to pH, sea water composition and phosphate sensitivity. We also characterise the active forms in sea water and determine the extent to which zooplankton generate phosphatase activity with respect to other plankton classes. In Toulon Bay, phosphatase was produced mostly by the microplankton fraction (>90 μm), accounting for more than 90% of total activity. In contrast, most of the phosphatase activity in Le Niel Bay was generated by the nanoplankton fraction (5–90 μm) and the picoplankton fraction (0.25–5 μm). The microplankton enzymes had non Michaelis-Menten kinetics suggesting the involvement of multiple enzyme processes with distinct kinetic constants. This activity is in major part secreted into the sea water and is stimulated by the ionic strength and the pH of the sea water. Cypris larvae of the genus Balanus played a special role in this release. For the nanoplankton and picoplankton, part of this activity was due to non-secreted enzymes, probably bound to membranes or occurring intracellularly. Moreover, nano and picoplankton phosphatase required higher pH than microplankton enzyme. For all plankton size classes, there was no activity at low pH, suggesting that acid phosphatases were not involved in reactions with substrates dissolved in water. 相似文献
8.
Mauro Celussi Alessandro Paoli Erica Crevatin Andrea Bergamasco Francesca Margiotta Vincenzo Saggiomo Serena Fonda Umani Paola Del Negro 《Estuarine, Coastal and Shelf Science》2009,81(4):491-500
During the 2006 Italian Antarctic expedition a diel sampling was performed close to Cape Hallett (Ross Sea) during the Austral summer. Under-ice seawater samples (4 m) were collected every 2 h for 28 h in order to estimate prokaryotic processes' variability and community structure dynamics. Prokaryotic and viral abundances, exoenzymatic activities (β-glucosidase, chitinase, lipase, alkaline phosphatase and leucine aminopeptidase), prokaryotic carbon production (3H-leucine incorporation) and community structure (Denaturing Gradient Gel Electrophoresis – DGGE fingerprints) were analysed. Results showed that the diel variability of the prokaryotic activity followed a variation in salinity, probably as a consequence of the periodical thawing of sea ice (driven by solar radiation and air temperature cycles), while negligible variation in viral and prokaryotic abundances occurred. The Bacterial and Archaeal community structures underwent an Operational Taxonomic Units (OTUs) temporal shift from the beginning to the end of the sampling, while Flavobacteria-specific primers highlighted high variations in this group possibly related to sea ice melting and substrate release. 相似文献
9.
Baoxiao Qu Jinming Song Huamao Yuan Xuegang Li Ning Li Liqin Duan 《Journal of Oceanography》2017,73(3):365-382
In this work, we examined the carbonate parameters, i.e. total alkalinity (TA), pH, and partial pressure of CO2 (pCO2), and the air–sea CO2 flux (FCO2) in the continental shelves of the southern Yellow Sea (SYS) and East China Sea (ECS), based on two field surveys conducted in April and August of 2011. Surface pCO2 showed significant spatial variations, ranging from 246 to 686 µatm in spring (average ± standard deviation = 379 ± 95 µatm) and from 178 to 680 µatm in summer (384 ± 114 µatm). During the spring cruise, the central SYS (pCO2 < 240 µatm) and the Changjiang estuary (pCO2 < 300 µatm) were under-saturated with CO2, while the southern SYS and the southwestern ECS were supersaturated (pCO2 = 420–680 µatm). In summer, however, the CO2-supersaturated waters (pCO2 = 380–680 µatm) occupied a relatively wide area, including the nearshore of the SYS and the Changjiang estuary, whereas pCO2-deficient water (pCO2 = 220–380 µatm) was observed only at the offshore ECS. In general, the entire SYS and ECS area behaved as a sustained CO2 sink, with average FCO2 of ?3.9 and ?2.1 mmol m?2 d?1 in spring and summer, respectively. Phytoplankton production was the driving force for CO2 absorption, especially during the spring cruise. In addition, we found that typical water mixing processes and decomposition of terrestrial material were responsible for the release of CO2 in three turbidity maximum regions. 相似文献
10.
Seasonal variations of macrobenthos communities were analyzed over six years at two fixed stations at the depths of 500 m and 1,000 m in the bathyal zone off Sanriku, northeastern Japan, and were compared with those of the 80 m station established at the mouth of Otsuchi Bay, northeastern Japan. Significant seasonal variations of macrobenthos density were detected at the 80 m and 500 m stations. While the density increased in late spring and decreased until July at the 80 m station, it increased between May and August, and decreased in September at the 500 m station. At the 1,000 m station, no seasonal variation of macrobenthos abundance could be detected. The seasonal variations of the density observed at the 80 m and 500 m stations are probably related to that of the supply of organic materials derived from surface phytoplankton. Differences in the patterns of seasonal variations among the three stations may reflect the different periods of food supply to the sea floor. Significant seasonal variation in the feeding structure of the polychaete communities could be detected at the 80 m and 1,000 m stations. 相似文献
11.
海水胞外酶活性可以指示有机物的分布特征以及微生物的营养状况。我们测定了2017年3月25日至4月15日黄海和东海44个大面站以及2018年4月28日至29日胶州湾湾口附近海域10个站位表层海水中的8种胞外酶活性并研究了其分布特征。2017年春季黄、东海表层海水中碱性磷酸酶和脂肪酶活性较高，高值区出现在苏北沿岸和南黄海中部，碱性磷酸酶与磷酸盐浓度之间呈正相关。其余6种酶(肽酶、几丁质酶、纤维素酶、α-D-葡萄糖苷酶、β-D-半乳糖苷酶、木糖苷酶)活性高值区出现在长江口以东的外海，东海的β-D-半乳糖苷酶、木糖苷酶平均酶活性显著高于黄海。8种酶活性平均值排列顺序由大到小为:碱性磷酸酶、脂肪酶、肽酶、几丁质酶、α-D-葡萄糖苷酶、β-D-半乳糖苷酶、纤维素酶、木糖苷酶，其中α-D-葡萄糖苷酶和β-D-半乳糖苷酶的活性基本一致。2018年春季胶州湾附近海域海水中碱性磷酸酶、脂肪酶、木糖苷酶活性分布为近岸高于远岸，几丁质酶活性为近岸低于远岸。8种酶活性平均值排列顺序由大到小为:碱性磷酸酶、脂肪酶、肽酶、木糖苷酶、α-D-葡萄糖苷酶、β-D-半乳糖苷酶、几丁质酶、纤维素酶，其中几丁质酶和纤维素酶的活性基本一致。黄海的碱性磷酸酶和脂肪酶平均酶活性均显著高于东海和胶州湾附近海域。糖类水解酶(几丁质酶、纤维素酶、α-D-葡萄糖苷酶、β-D-半乳糖苷酶、木糖苷酶)平均酶活性在黄海最低。本文的结果对于理解中国近海海水有机碳的分布、浮游植物及异养细菌对有机碳的降解具有重要意义。 相似文献
12.
消化酶是反映机体消化生理状况及对营养物质利用能力的重要指标。本文对三疣梭子蟹蜕壳后不同时间肝胰腺消化酶活力进行了研究,结果显示,蜕壳后肝胰腺中胃蛋白酶、胰蛋白酶和淀粉酶活力在第4~6天达到最高;脂肪酶活力在第6天时达到最高;纤维素酶活力总体较低,在第10~12天达到最高;几丁质酶活力在蜕壳后第4天时酶活力最高。研究表明,三疣梭子蟹蜕壳后,胰蛋白酶和胃蛋白酶活力相对较高,而纤维素酶和淀粉酶活力较低,可能与三疣梭子蟹本身的肉食性特征有关;另外,整个实验期间,三疣梭子蟹肝胰腺脂肪酶活力较低,可能与测定条件有一定的关系。与其他时间点相比,蜕壳后4~6 d(蜕壳周期中间阶段)各种酶活力处于较高水平,表明此阶段对食物的消化能力比其他时间更强,这为养殖过程中饵料的合理投喂提供了参考依据。 相似文献
13.
The abundance of baroduric bacteria from nine sediment cores (0–10 cm below sea floor) was examined for their response to simulated benthic disturbance in the Central Indian basin (CIB). While the total counts of bacteria decreased from 109 to 106 g?1 dry wt sediment, the average retrievable counts (CFU-colony forming units) improved by two orders of magnitude, i.e., from 102 104 g?1 dry wt sediment. The baroduric retrievable forms were dominated by Acinetobacter and Moraxella sp before the disturbance. After the disturbance the generic diversity was represented by Staphylococcus sp, Enterobacter sp, Micrococcus sp, Coryneforms sp, and Pseudomonas sp in addition to Acinetobacter. These observations were corroborated by changes in enzymatic activities of the retrievable bacteria, which could lead to changes in the biochemical characteristics of the sediment. Thus the simulated disturbance brought about an increase in culturable abundance, taxonomic and functional diversity of deep-sea sediment of the CIB. 相似文献
14.
Anirban Akhand Abhra Chanda Sachinandan Dutta Sudip Manna Sugata Hazra Debasis Mitra K. H. Rao V. K. Dadhwal 《Journal of Oceanography》2013,69(6):687-697
The distribution of the fugacity of CO2 ( $ f_{{{\text{CO}}_{ 2} }} $ ) and air–sea CO2 exchange were comprehensively investigated in the outer estuary to offshore shallow water region (lying adjacent to the Sundarban mangrove forest) covering an area of ~2,000 km2 in the northern Bay of Bengal during the winter. A total of ten sampling surveys were conducted between 1 December, 2011 and 21 February, 2012. Physico-chemical variables like sea surface temperature (SST), salinity, pH, total alkalinity (TAlk), dissolved inorganic carbon (DIC) and in vivo chlorophyll-a along with atmospheric variables were measured in order to study their role in controlling the CO2 flux. Surface water $ f_{{{\text{CO}}_{ 2} }} $ ranged between 111 and 459 μatm which correlated significantly with the SST (r = 0.71, p < 0.001, n = 62). Neither DIC nor TAlk showed any linear relationship with varying salinity in the estuarine mixing zone, demonstrating the significant presence of non-carbonate alkalinity. An overall net biological control on the surface $ f_{{{\text{CO}}_{ 2} }} $ distribution was established during the study, although no significant correlation was found between chlorophyll-a and $ f_{{{\text{CO}}_{ 2} }} $ (water). The shallow water region studied was mostly under-saturated with CO2 and acted as a sink for atmospheric CO2. The difference between surface water and atmospheric $ f_{{{\text{CO}}_{ 2} }} $ ( $ \Updelta f_{{{\text{CO}}_{ 2} }} $ ) ranged from ?274 to 69 μatm, with an average seaward flux of ?10.5 ± 12.6 μmol m?2 h?1. The $ \Updelta f_{{{\text{CO}}_{ 2} }} $ and hence the air–sea CO2 exchange was primarily regulated by the variation in sea surface $ f_{{{\text{CO}}_{ 2} }} $ , since atmospheric $ f_{{{\text{CO}}_{ 2} }} $ varied over a comparatively narrow range of 361.23–399.05 μatm. 相似文献
15.
南海北部春季非水华期的CO_2分压及其调控 总被引：1，自引：0，他引：1
针对南海北部和吕宋海峡附近海域的海-气CO2通量及其调控问题,研究了2009年3月底至4月中旬在这些海域通过走航观测的方法取得的海-气CO2分压和海表温度、盐度等相关数据。结果表明,在河口、沿岸流以外的南海北部开阔海域,与大气平衡的CO2分压分布在368~380μatm,南低北高,平均值为371μatm;而海表CO2分压分布在293~405μatm,南高北低。南海北部开阔海域的海表CO2分压主要受温度效应调控,也在一定程度上受水团混合、海-气交换、生物活动等非温度效应的影响。在相同水温条件下,黑潮区的海表CO2分压比南海北部的海表CO2分压低。本研究和大多数前人研究的结果都表明,南海北部海盆区域和吕宋海峡西侧海域在春季与大气CO2接近源汇平衡,而非大气CO2的显著源区。 相似文献
16.
Marguerite S. Koch Demetris C. Kletou Rosanna Tursi 《Estuarine, Coastal and Shelf Science》2009,83(4):403-413
Few phosphorus-depleted coastal ecosystems have been examined for their ability to hydrolyze phosphomonoesters. We examined seasonal (August 2006–April 2007) alkaline phosphatase activity in Florida Bay, a phosphorus-limited shallow estuary, using fluorescent substrate at low concentrations (≤2.0 μM). In situ dissolved inorganic and organic phosphorus levels and phosphomonoester concentrations were also determined. Water column alkaline phosphatase activity was partitioned into two particulate size fractions (>1.2 and 0.2–1.2 μm) and freely dissolved enzymes (<0.2 μm). Water column alkaline phosphatase activity was also compared to leaf and epiphyte activity of the dominant tropical seagrass Thalassia testudinum. Our results indicate: (1) potential alkaline phosphatase activity in Florida Bay is high compared to other marine ecosystems, resulting in rapid phosphomonoester turnover times (2 h). (2) Water column alkaline phosphatase activity dominates, and is split equally between particulate and dissolved fractions. (3) Alkaline phosphatase activity was highest during cyanobacterial blooms, but not when normalized to chl a. These results suggest that dissolved, heterotrophic and autotrophic alkaline phosphatase activity is stimulated by phytoplankton blooms. (4) The dissolved alkaline phosphatase activity is relatively constant, while the particulate activity is seasonally and spatially dynamic, typically associated with phytoplankton blooms. (5) Phosphomonoester concentrations throughout the bay are low, even though potential hydrolysis rates are high. We propose that bioavailable dissolved organic P is hydrolyzed by dissolved and microbial alkaline phosphatase enzymes in Florida Bay. High alkaline phosphatase activity in the bay is also promoted by long hydraulic residence times. This background activity is primarily driven by carbon and phosphorus limitation of microorganisms, and regeneration of enzymes associated with cell lysis. Pulses of inorganic phosphorus and labile organic phosphorus and nitrogen may stimulate autotrophs, particularly cyanobacteria, which in turn promote biological activity that increase alkaline phosphatase activity of both autotrophs and heterotrophs in the bay. 相似文献
17.
Analysis of microbiological and chitinase activities relative to the white shrimpPenaeus setiferus, and its chitinoclastic endosymbionts, have demonstrated the relevance of total chitinolytic processes in penaeid biology. Microorganisms may serve as a direct source of nutrients for the animal as well as in the elaboration of extracellularin situ chitinase enzymes. The enzyme produced by the predominant gut bacteria,Beneckea neptuna, is a moderately actively inducible chitinase while the shrimp has an indigenous constitutive chitinase and chitobiase system. Factors of temperature, pH, ion inhibition and reducing sugar ratios have been compared for the bacterial and animal enzymes. This dual enzyme system suggests that metabolic chitin transformation may play a vital role in crustacean metabolism. 相似文献
18.
Marginal seas play important roles in regulating the global carbon budget, but there are great uncertainties in estimating carbon sources and sinks in the continental margins. A Pacific basin-wide physical-biogeochemical model is used to estimate primary productivity and air-sea CO_2 flux in the South China Sea(SCS), the East China Sea(ECS), and the Yellow Sea(YS). The model is forced with daily air-sea fluxes which are derived from the NCEP2 reanalysis from 1982 to 2005. During the period of time, the modeled monthly-mean air-sea CO_2 fluxes in these three marginal seas altered from an atmospheric carbon sink in winter to a source in summer. On annualmean basis, the SCS acts as a source of carbon to the atmosphere(16 Tg/a, calculated by carbon, released to the atmosphere), and the ECS and the YS are sinks for atmospheric carbon(–6.73 Tg/a and –5.23 Tg/a, respectively,absorbed by the ocean). The model results suggest that the sea surface temperature(SST) controls the spatial and temporal variations of the oceanic pCO_2 in the SCS and ECS, and biological removal of carbon plays a compensating role in modulating the variability of the oceanic pCO_2 and determining its strength in each sea,especially in the ECS and the SCS. However, the biological activity is the dominating factor for controlling the oceanic pCO_2 in the YS. The modeled depth-integrated primary production(IPP) over the euphotic zone shows seasonal variation features with annual-mean values of 293, 297, and 315 mg/(m~2·d) in the SCS, the ECS, and the YS, respectively. The model-integrated annual-mean new production(uptake of nitrate) values, as in carbon units, are 103, 109, and 139 mg/(m~2·d), which yield the f-ratios of 0.35, 0.37, and 0.45 for the SCS, the ECS, and the YS, respectively. Compared to the productivity in the ECS and the YS, the seasonal variation of biological productivity in the SCS is rather weak. The atmospheric pCO_2 increases from 1982 to 2005, which is consistent with the anthropogenic CO_2 input to the atmosphere. The oceanic pCO_2 increases in responses to the atmospheric pCO_2 that drives air-sea CO_2 flux in the model. The modeled increase rate of oceanic pCO_2 is0.91 μatm/a in the YS, 1.04 μatm/a in the ECS, and 1.66 μatm/a in the SCS, respectively. 相似文献
19.
Reliable methods have been developed for the quantitative estimation of chitin, chitosan and chitin deacetylase in sediment samples, as well as two methods for the estimation of chitinase in these samples. The differing substrates used in the latter two methods have produced distinct ‘depth profiles’ for chitinase activity which suggest the presence of more than one chitinolytic system in the sediments of the Ythan estuary. Studies on the mineralization of chitin in these sediments have revealed a complex system with a number of unexpected features. The rate of chitin degradation was reduced in late summer, possibly due to the heavy seaweed growth which covers the mud flats at this time, although the potential degradative activities of the enzymes chitinase and chitin deacetylase were higher in summer than in winter. The proportional rates of degradation of chitin, chitosan and cellulose were similar in both the absence and presence of seaweed overgrowth, although the apparent rates of degradation of these substrates were higher in the absence of seaweeds. Core samples have indicated that the major input of chitin to the sediment ecosystem occurs via deposition at the surface, while the input of chitosan (the deacetylated polymer) occurs via its production within the sediment, primarily within the upper 5 cm of sediment. The concentrations of both these polymers decreased sharply below an ‘interface’ between aerobic and anoxic sediments. 相似文献
20.
Lectins are sugar-specific binding proteins or glycoproteins that play important physiological roles in cellular recognition and regulation. And they are also valuable in medicine and pharmacy. Tubeworm is the representative species around the hydrothermal vent in the deep sea. They have developed unique mechanisms to adapt to the harsh environment. In this study, a 1 092 bp c DNA, designed as rpgal, was first cloned and characterized from the tubeworm Ridgeia piscesae. Sequence analysis showed that RPGAL had low homology with the known galectin. And it had two homologous carbohydrate-recognition domains, which is the characteristic of the tandem-repeat type galectins. The RPGAL was successfully recombinant expressed in Escherichia coli and purified. Analysis of biological activity revealed that RPGAL was metal ion independent and it could agglutinate all the vertebrate erythrocytes tested. It was stable at 10–50°C and p H 5–10. And the hemagglutinating activity of RPGAL was strongly inhibited by D-Lactose and lipopolysaccharide. Although RPGAL had no effect on the microorganisms tested, it showed anti-tumor activity towards He La cells and HT1080 cells, which was accomplished by apoptosis. The study demonstrated that RPGAL was a novel galectin and provided a potential candidate for therapy of anti-tumor. 相似文献