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The effects of a diet containing Hanseniaspora opuntiae C21 on growth and digestive enzyme activity were estimated in juvenile Apostichopus japonicus. Groups of sea cucumbers were fed diets containing H. opuntiae C21 at 0(control), 10 4, 10 5, and 10 6 CFU(colony-forming units)/g feed. Results showed that after 45 d the specific growth rate(SGR) of sea cucumbers fed a C21-supplemented diet at 10 4 CFU/g feed was significantly higher than that of the control( P 0.05). Intestinal trypsin and lipase activities were significantly enhanced by C21 administration at 10 4 and 10 5 CFU/g feed compared with the control( P 0.05). After feeding for 23–42 d, C21 was demonstrated by denaturing gradient gel electrophoresis to be present in the intestine of sea cucumbers. In addition, after feeding the C21-supplemented diets for 15 d, the sea cucumbers were switched to an unsupplemented diet and C21 was confirmed to be capable of colonizing the intestine for at least 31 d after cessation of feeding. In conclusion, C21 was shown to successfully colonize the intestine of juvenile A. japonicus via dietary supplementation, and improve growth and digestive enzyme activity. 相似文献
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The aim of the study was to examine the bacterial community associated with the intestinal mucus of young farmed puffer fish Takifugu rubripes. Polymerase chain reaction and partial 16 S r DNA sequencing was performed on DNA from bacteria cultivated on Zobell 2216 E medium. All the isolates were classified into two phyla—Proteobacteria and Firmicutes. Proteobacteria were the dominant, culturable intestinal microbiota(68.3%). At the genus level, V ibrio, Enterobacter, Bacillus, Pseudomonas, Exiguobacterium, Staphylococcus, Acinetobacter, Pseudoalteromonas and S hewanella were isolated from the intestine, with representatives of the genera V ibrio, Enterobacter and Bacillus accounting for 70.7% of the total. This is the first report of Enterobacter, Bacillus, Exiguobacterium and Staphylococcus as part of the intestinal bacterial microflora in T. rubripes. The profile of the culturable bacterial community differed between samples collected from the same tank at 2-month intervals, as indicated by Bray-Curtis and Sorensen indices, and the impact on the intestinal physiology and health of puffer fish requires further investigation. 相似文献
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We isolated a bacterial strain (HC4) that is able to degrade κ-carrageenan from a live specimen of the red alga Hyalosiphonia caespitosa. With 16S rRNA gene sequencing, we identified the strain as Tamlana sp., and then purified an extracellular κ-carrageenase from a culture of Tamlana sp. HC4 by ammonium sulfate precipitation, Sephadex G-200 gel filtration chromatography, and DE-cellulose 52 anion-exchange
chromatography. The purified enzyme yields a single band on SDS-PAGE with a molecular mass of 66.4 kDa. The optimal pH and
temperature for κ-carrageenase activity are at 8.0 and 30°C, respectively. The enzyme is stable over the range of pH 7.2–8.6
below 45°C. The enzyme activity is strongly inhibited by Zn2+ and Cu2+ at 1 mmol/L. The enzyme-catalyzed reaction follows Michaelis-Menten kinetics with the Michaelis constant (K
m
) at 7.63 mg/ml. Analysis of the degradation products of the κ-carrageenase by ESI-MS and 13C-NMR spectroscopy indicates that the enzyme degrades κ-carrageenan down to the level of κ-neocarrabiose sulfate. 相似文献
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This study examines the impacts of short-term(6 months) fertilization on the community structure and abundance of ammonia-oxidizing betaproteobacteria(β-AOB) and the potential nitrification rate in sediment colonized by S uaeda heteroptera in a saltmarsh located in Shuangtai estuary, China. The sediment samples were collected from plots treated with different amounts of an N fertilizer(urea supplied at 0.1, 0.2, 0.4, and 0.8 g/kg(nitrogen content in dry sediment)), and with different forms of N fertilizers(urea,(NH4) 2 SO 4, and NH_4NO_3, each supplied at 0.2 g/kg). The fertilizers were applied 1–4 times during the plant-growing season in May, July, August and September of 2013. Untreated plots were included as a control. As revealed in denaturing gradient gel electrophoresis of the 16 S r RNA gene, the β-AOB community responded to both the amount and form of N. Real-time quantitative PCR indicated that both abundance and potential nitrification rate of β-AOB increased after N addition, regardless of concentration and form(except NH_4NO_3). These results provide evidence that short-term N application influences the sediment β-AOB community, β-AOB abundance and potential nitrification rate in a saltmarsh ecosystem. 相似文献
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本研究确定了獐子岛集团虾夷扇贝Patinopecten yessoensis育苗过程中幼体大规模死亡的病原菌。采用TCBS培养基从患病幼体中分离弧菌,其数量为1.12×104 CFU/g,以V1菌株和V2菌株为优势菌,占总弧菌数的64.3%和32.1%。用血琼脂平板测定V1菌株和V2菌株的溶血性,2株菌分别呈β溶血和α溶血。用2株菌分别感染扇贝幼体,幼体的死亡率显著高于对照组(P<0.05),症状与自然状态下的发病症状一致,并且从感染死亡的幼体中分离到原感染菌株,确定V1菌株和V2菌株是造成扇贝幼体大规模死亡的病原菌。对2株病原菌进行致病基因分析,结果发现V1菌株含有胞外金属蛋白酶基因。经16S rRNA基因测序分析,V1菌株(GenBank登录号KR232924)和V2菌株(GenBank登录号KR232925)与Vibrio splendidus ctt 31/5 和 Vibrio tasmaniensis 007的相似度分别为99.9%和99.2%。用药敏纸片扩散法检测病原菌对常见抗生素的敏感性,结果表明利福平、氟苯尼考和磺胺异恶唑均能有效抑制病原菌的生长。 相似文献
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施肥对盐沼沉积物微生物生物量和细菌群落组成的影响 总被引：1，自引：1，他引：0
The effects of nitrogen(N) addition on microbial biomass, bacterial abundance, and community composition in sediment colonized by Suaeda heteroptera were examined by chloroform fumigation extraction method, real-time quantitative polymerase chain reaction, and denaturing gradient gel electrophoresis(DGGE) in a salt marsh located in Shuangtai Estuary, China. The sediment samples were collected from plots treated with different amounts of a single N fertilizer(urea supplied at 0.1, 0.2, 0.4 and 0.8 g/kg(nitrogen content in sediment) and different forms of N fertilizers(urea,(NH_4)_2SO_4, and NH_4NO_3, each supplied at 0.2 g/kg(calculated by nitrogen).The fertilizers were applied 1–4 times during the plant-growing season in May, July, August, and September of 2013. Untreated plots were included as a control. The results showed that both the amount and form of N positively influenced microbial biomass carbon, microbial biomass nitrogen, and bacterial abundance. The DGGE profiles revealed that the bacterial community composition was also affected by the amount and form of N.Thus, our findings indicate that short-term N amendment increases microbial biomass and bacterial abundance,and alters the structure of bacterial community. 相似文献
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为了解大连新港7.16溢油事故发生后5年间大连湾受污染海区生态恢复程度,同时探究大连湾表层海水和沉积物中微生物对石油污染的长期响应策略,对大连湾表层海水和沉积物中石油烃含量的分布、异养细菌和石油烃降解菌丰度的年度变化特征,以及细菌丰度与环境因子间相关性进行了研究。结果表明,溢油事故发生后2年间,大连湾表层海水中石油烃含量由溢油初期2010年9月的0.22~0.67 mg/L降到0.0025~0.05 mg/L(2012年5月),海水质量也由三类海水转变为一类海水;沿岸站位BQ012表层沉积物中石油烃含量也由2011年12月的7 133μg/g降低到2014年的926μg/g,其表层沉积物质量也由三类转变为一类沉积物质量标准。溢油后2个月内表层海水中异养细菌及石油烃降解菌丰度升高至105CFU/m L和104CFU/m L,随着时间推移各站位细菌丰度基本呈下降趋势,5年后细菌丰度回落了1~2个数量级并恢复到溢油前的历史水平。表层沉积物中石油烃降解菌丰度由溢油后2个月的105CFU/g降低到2013年的102CFU/g。石油烃降解菌与异养细菌的比值(HDB/HB)与石油烃含量呈极显著的正相关(P0.01),而与营养盐和溶解氧等主要环境因子相关性不大,因此认为其可作为海水中石油烃类污染评价的指标。 相似文献
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