Cloning and nucleotide sequence of D-hydantoinase gene of marine polyphosphate-accumulating bacterium, Halomonas sp. YSR-3

Hydantoinase is involved in the production of optically pure amino acids from racemic 5-mono-substituted hydantoins. We measured the D-hydantoinase activity in marine Halomonas sp. YSR-3 and amplified the D-hydantoinase gene by PCR. The gene was inserted into vector pGM-T and transformed into E. coli TOP10. The positive transformants with the D-hydantoinase gene were sequenced. The sequenced fragment comprises 1 510 base pairs. The D-hydantoinase gene from YSR-3 is 77% similar to that from Pseudomonas entornophila L4 by searching against the NCBI databse. The protein product of the YSR-3 D-hydantoinase gene is 75%, 73%, and 70% similar to those from Pseudomonasfluorescens Pf-5, Marinornonas sp. MED121, and Burkholderia vietnamiensis G4, respectively. The difference of the D-hydantoinase gene between marine Halornonas sp. YSR-3 and other terrestrial organisms is distinct.

Storage and Subsequent Reactivation of Phosphate-Accumulating Aerobic Granules

Phosphate-accumulating aerobic granules cultivated in a sequencing batch reactor were composed of inner rod-shaped bacteria aggregates and outer twining filamentous bacteria. The influence of two-month storage under dif- ferent conditions on the storage and subsequent reactivation performance of aerobic granules was investigated. After two-month storage the granules sealed at 4 ~C in distilled water or normal saline （named granules A and granules B, respectively） could maintain their characteristics as before, while the granules idled in the reactor at room temperature （named granules C） exhibited decreased properties. During reactivation, granules A and granules B presented almost identical recovery performance, faster than granules C, in terms of phosphorus removal efficiency, mixed liquor sus- pended solids （MLSS）, phosphate release and accumulating ability. The results suggest that hermetical storage at low temperature promoted the maintenance of the granular properties and the reviving behaviors of phosphateaccumulating aerobic granules, and storage medium had little influence on the storage and recovery perfomlance.

Biomass Fraction of Phosphate-Accumulating Organisms Grown in Anoxic and Aerobic Stages under Optimum Nitrate Concentration

The effects of nitrate concentration on the capability of phosphorus uptake in the main anoxic stage were investigated.Meanwhile, the biomass fractions — heterotrophs, phosphateaccumulating organisms( PAOs),and nitrifying organisms in a pilot-scale enhanced biological phosphorus removal( EBPR) system— were both experimentally and theoretically evaluated( from the mass balance calculations of organic matter, nitrogen and phosphorus),under optimum nitrate concentration in the main anoxic stage,in which the influent chemical oxygen demand( COD)concentration was stabilized at( 290 ± 10) mg·L- 1and the influent total phosphorus( TP) concentration was stabilized at( 7. 0 ± 0. 5)mg · L- 1. In long term operations,the process exhibited high performance in removing organic matter, nitrogen, and phosphorus. Approximately 46. 41% of organic matter,57. 21% of nitrogen,and 48. 14% of phosphorus were removed from the influent in the form of carbon dioxide,nitrogen gas,and polyphosphate,respectively. XH( heterotrophs),XPAO( PAOs),and XAUT( autotrophs) were regarded as the major organisms responsible for biomass production. The yield fractions of XHgrowth in the first anoxic,the second anoxic,and the aerobic stages were 10. 24%,19. 11%,and 19. 71%,respectively; the yield fractions of XPAO growth in the second anoxic and the aerobic stages were 24. 34% and19. 86%,respectively; the yield fraction of XAUTgrowth in the aerobic stage was 6. 74%. These results showed that XHand XPAOformed the major community. Moreover,a higher amount of XPAOgrowth on stored poly-hydroxyalkanoates( PHAs) under the anoxic condition was seen in this EBPR system for municipal wastewater treatment.

Isolation and Identification of Phosphate-accumulating Strain PAO3-1 and Its Phosphorus Removal Characteristics

A phosphate-accumulating bacteria strain PAO3-1 was isolated from biological phosphorus removal sludge supplied with sodium acetate as carbon source under stable performance. This strain has good enhanced biological phosphorus removal effect on normal activated sludge system. Phosphorus removal ratio was raised form 44% with no added strain to more than 82% with strain strengthening biological phosphorus removal. It is identified to be Alcaligenes sp. according to its morphology, biochemical characteristics and 16S rDNA sequence analysis. The cell of strain PAO3-1 is straight bacilli form, 0.4×1.1μm, no flagellum, gram negative and special aerobiotic. The optimal temperature and pH for growth are 32℃-37℃ and 5.5-9.5, respectively. The shape of slant clone is feathery. The phosphate accumulating rate of strain PAO3-1 was 8.1mgP/g cell·h, and 14.3 mgP/g cell·h when in phosphate-starving situation, which was 76.5% higher than that in non-starving situation. Its phosphate release rate of log course in anaerobic phase and in culture without phosphorus was 7.6mgP/g cell·h, while in stable course the rate was 6.1mgP/g cell·h. The rate in stable course was 19.7% lower than that in log course.

科学术语的翻译实践及其概念的语境重置——从“bacterium”到“细菌”

19世纪末20世纪初,“bacterium”概念由西方传播至我国,并最终以“细菌”二字成为汉语词。这是一则外来概念在华传播的成功案例。“细菌”的入华“旅行”先后经历了术语“bacterium”的翻译实践、概念“bacterium”的在华接受及译词“细菌”的最终确立。“微虫”“微生物”“微菌”“霉菌”“微生毒”“微生虫”“璧他利亚”等译词的涌现、共存与淘汰体现了概念跨文化传播在语言层面的复杂表征,语境重置则是此番过程的本质。汉语语境“虫”概念和本土传统的病因学体系为“旅行”概念的接受创造条件。“细菌”二字被确立为术语“bacterium”的译词则是社会权力制约下的结果。深入挖掘这则成功案例,厘清概念跨文化传输的特点,或能为提升概念跨文化传播效率提供些许启示。

Identification of an Algae-lysing Bacterium of Anabaena flosaquae and Primary Research on Their Relationship

[Objective] The aim was to explore the relationship between alage-lysing bacterium and Anabaena flosaquae so as to provide reference for the control of bloom. [Method] An algae-lysing bacterium strain named S7 was isolated from eu- trophic river. The lyric efficiency and performing mode of S7 strain to Anabaena flos- aquae was studied. Influence of different environmental factors and the relationship between S7 strain and Anabaena flosaquae was also studied, and then the bacteri- um strain was physiologically identified. [Result] More than 90% of Anabaena flos- aquae had been removed by 7 d when the volume ratio of medium to algae solu- tion was 30%, the pH was 9 and the temperature was 35 ℃. These results also showed that a mutual inhibit relationship existed between S7 strain and Anabaena flos-aquae. The S7 strain killed the algae by indirectly through certain lyric agents in absence of direct contact with the target but by secreting metabolites. Moreover, these lyric agents also had the thermostability. 16SrDNA sequence analysis showed that S7 strain belonged to Chryseobacterium sp. [Conclusion] The examined Poly-p proved that S7 strain is polyphosphate accumulating bacteria （PAOs） and has better lyric efficiency.

厌氧细菌Acetanaerobacterium elongatum从葡萄糖的产氢特性研究

为了了解影响厌氧发酵产氢细菌Acetanaerobacterium elongatumZ7产氢效率的因素,采用生理学方法对其进行了研究。结果表明:乙醇型发酵菌A.elongatumZ7的最适产氢温度为37℃,最适产氢的起始pH为8.0。该菌发酵葡萄糖和阿拉伯糖产氢的能力较强,氢气产率分别为1.55mol H2/mol葡萄糖和1.50mol H2/mol阿拉伯糖。酵母粉是菌株Z7生长和产氢所必须的生长因子;pH影响菌株的生长和葡萄糖利用率;氢压则影响电子流的分配,从而改变代谢产物乙酸和乙醇的比例;当产氢菌与甲烷菌共培养以维持发酵体系低的氢压时,可使氢的理论产量提高约4倍;培养基中乙酸钠浓度>60mmol/L明显抑制产氢。另外,一个只利用蛋白类物质的细菌能够促进菌株Z7对葡萄糖的利用,进而提供氢产量,为生物制氢的工业化生产提供理论参考。

高效产氢细菌新种——Ethanologenbacterium sp.X-1的分离鉴定及其产氢效能

为获得高效产氢发酵细菌 ,采用改进的厌氧Hungate培养技术 ,从生物制氢反应器CSTR中分离一株产氢细菌X 1。对该株细菌进行了形态学特征、生理生化指标、16SrDNA和 16S 2 3SrDNA间隔区序列分析等研究。结果表明与最相近的种属Clostridiumcellulosi和Acetanaerobacteriumelongatum等的 16SrRNA基因序列同源性为 94 %以下。16S 2 3SrRNA间隔区基因序列比对分析显示保守区域仅为tRNAAla和tRNAIle序列 ,其它可变部位没有同源性区域 ,鉴定为新属Ethanologenbacteriumsp .。该株细菌为专性厌氧杆菌 ,代谢特征为乙醇发酵 ,葡萄糖发酵产物主要为乙醇、乙酸、H2 和CO2 。在pH4 0和 36℃条件下最大产氢速率是 2 8 3mmolH2 (gdrycell·h)。

一株耐锌细菌Sphingobacterium caeni S3的Zn2+吸附特征

以一株耐锌细菌S3为研究对象,对其菌体及其胞外聚合物(EPS)的Zn^2+吸附特征进行研究.结果表明,菌株S3属于鞘氨醇杆菌属(Sphingobacterium),其序列与S.caeni相似性达到99%.Zn^2+对菌株S3生长的最小抑制浓度为500 mg·L^-1左右.S3活性菌体对Zn^2+的吸附率明显高于非活性菌体,且活性菌体实现吸附平衡的时间稍长.参与S3菌体Zn^2+吸附过程的官能团主要有缔合O-H、N-H和多糖的C-O.菌体EPS对Zn^2+的吸附率随时间延长逐渐增大,在80 min达到吸附平衡.S3菌体及EPS对Zn^2+的吸附过程均可采用准二级动力学模型进行描述.

Cultural and luminescent Conditions of a Marine luminous Bacterium

Study of marine noctilucence in marine is important to fishery, environmental monitoring and military affairs. A luminous bacterial strain D2 was isolated from the marine sediment samples collected near Donghai Island in Zhanjiang, China. The primary cultural and luminescent conditions of luminous bacterium D2 which was identified as Vibrio sp. were determined in liquid culture. The results showed that pH 7.0, 35 ℃, with 2.0 % NaCI, were the best growth conditions, and pH5 - 6, 20℃, OD600 0.08, with 3.0 % NaCI, were the optimal luminescent conditions.

Screening and Identification of Antagonistic Bacterium ZG-10 against Spot Blotch Disease in Pakchoi

[ Objective] The purpose was to screen bacterium with antagonistic effect against pathogen of spot blotch disease in pakchoi in vegetable field. [Method] More than 200 strains of bacteria which could produce spore were isolated from soil in different places. Through screening and rescreening, the bacteria with higher antibacterial activity were conducted observation about thallus shapes and colony characters, a series of physiological and biochemical tests were performed. [Result] Rescreening results indicated that the strains including ZG-10, ZG-19, ZG-59, ZG-72 and ZG-31 had significant antibacterial activity, which had very high research value and good application prospect for biocontrol on spot blotch disease in pakchoi; the strain ZG-10 was identified to be Bacillus subtilis. [ Conclusion] The strain ZG-10 had biocontrol potential and good development prospect. This research laid certain basis for subsequent research and strated a new way for the application of antagonistic strain and proteinum polypeptide in agdculture.

来源于P.bacterium 1109的甘露醇脱氢酶的重组纯化及酶学性质研究

本文将来自P.bacterium 1109的甘露糖醇脱氢酶(MDH)表达并提取纯化,研究了该重组酶的酶学性质及其在甘露醇生产中的工艺条件。结果显示重组MDH是一个相对分子量为37 kDa的四聚体。氨基酸序列比对发现其与大多数MDHs的同源性小于40%。该酶的最适pH和温度分别为8.5和80℃,且当金属离子Zn^(2+)存在时,重组MDH的活力提高到对照组的260%。此外,重组MDH在75℃孵育6 h后仍可保留超过85%的残留活性,热稳定性较高,比大多数MDHs的活性高。底物特异性研究表明其对D-果糖具有较高的专一性。重组MDH催化D-果糖的米氏常数(K_m)和催化效率(k_(cat)/K_m)分别为20 mmol/L和7.5 L/(mmol·min)。重组MDH在以400 mmol/L的D-果糖为底物的反应系统中,可将80%以上的D-果糖转化为甘露糖醇。通过对反应条件的优化,为后续工业化生产制备甘露醇奠定了基础。

Effect of Sulfate Reduced Bacterium on Corrosion Behavior of 10CrMoAl Steel

The effects of sulfate reduced bacterium （SRB） on the corrosion behavior of 10CrMoAl steel in seawater were studied by chemical immersion, potentiodynamic polarization, electrochemical impedance spectroscopy measurement, and scanning electron microscope techniques. The results show that the content of element sulfur in the corrosion product of 10CrMoAl steel in seawater with SRB is up to 9. 23 %, which is higher than that of the same in sterile seawater. X-ray diffraction demonstrates that the main corrosion product is FeS. SRB increases the corrosion rate by anodic depolarization of the metabolized sulfide product. SEM observation indicates that the corrosion product is not distributed continuously; in addition, bacilliform sulfate-reduced bacterium accumulates on the local surface of 10CrMoAl steel. Hence, SRB enhances sensitivity to the localized corrosion of 10CrMoAl steel in seawater.

Purification and Characterization of 2-Haloacid Dehalogenase from Marine Bacterium Paracoccus sp. DEH99, Isolated from Marine Sponge Hymeniacidon perlevis

2-haloacid dehalogenases constitute a group of dehalogenases which are capable of dehalogenating the halogenated organic compounds. So far, the 2-haloacid dehalogenases have been found in many bacteria, but not in Paracoccus genus. In the present study, one enzyme 2-haloacid dehalogenase(designated as Deh99), induced by DL-2-chloropropionate(DL-2-CPA), was purified from the marine bacterium Paracoccus sp. DEH99, isolated from marine sponge Hymeniacidon perlevis. The enzyme of Deh99 was purified to homogeneity by ammonium sulfate precipitation, ion exchange chromatography(Q-Sepharose HP), and Superdex 200 gel filtration chromatography. The molecular weight of Deh99 was estimated to be 25.0 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE), and 50.0 kDa natively by gel filtration chromatography. The enzyme of Deh99 stereospecifically dehalogenated L-2-CPA to produce D-lactate, with an apparent Michaelis-Menten constant(Km) value of 0.21 mmol L-1 for L-2-CPA. The optimal pH and temperature for Deh99 activity were 10.0 and 40℃, respectively. The enzyme of Deh99 acted on short-carbon-chain 2-haloacids, with the highest activity towards monochloroacetate. The activity of Deh99 was slightly affected by DTT and EDTA, but strongly inhibited by Cu2+ and Zn2+. The enzyme of Deh99 shows unique substrate specificity and inhibitor sensitivities compared to previously characterized 2-haloacid dehalogenases and is the reported one about purified 2-haloacid dehalogenase isolated from the bacteria of Paracoccus genus.

Isolation and characteristics of one marine psychrotrophic cellulase-generating bacterium Ar/w/b/75°/10/5 from Chuckchi Sea,Arctic

Microorganisms living in polar zones play an important part as the potential source of organic activity materials with low temperature characteristics in the bio-technological applications. A psychrotrophic bacterium (strain Ar/w/b/75°/10/5) , producing cellulose at low temperatures during late-exponential and early-stationary phases of cell growth, was isolated from sea ice-covered surface water in Chuckchi Sea, Arctic. This bacterium, with rod cells, was Gram-negative, slightly halophilic. Colony growing on agar plate was in black. Optimum growth temperature was 15℃. No cell growth was observed at 351 or above. Optimum salt concentration for cell growth was between 2 and 3 % of sodium chloride in media. Maximal cellulase activity was detected at a temperature of 35℃ and pH8. Cellulase was irreversibly inactivated when incubated at 55℃ within 30 min. Enzyme can be kept stable at the temperature no higher than 25℃. Of special interest was that this bacterium produced various extracellular enzymes including cellulase, amylase, agar hydrolase and protease, at low or moderate temperature conditions, which is certainly of it potential value for applications.

Extraction and physicochemical characteristics of a red pigment produced by marine bacterium strain S - 9801

A red pigment that has better biological properties is produced by marine bacterium strainS- 9801. The extraction methods, physicochemical and toxicity of the pigment have been studied. Dissolubility of pigment in the five organic solvent has been tested, and ethanol is optimally chosen for extraction. Physicochemical characteristics of this pigment was stable. The absorbance of the pigment solution was no losing when put under natural light for 10 days or treated by UV for 30 minutes, color of the pigment unchanged after 100℃ hythere for 1 h or 80 ℃ xerother for 2 h. The median lethal dose (LD_50) of the rat by celiac injection was 670.04 mg/kg and minimum lethal dose of oral was greater than 2 000 mg/kg.

The Antitumor Components from Marine-derived Bacterium Streptoverticillium luteoverticillatum 11014 Ⅱ

Eight known compounds were isolated from a marine-derived bacterium Streptoverticillium luteoverticillatum 11014 using bioassay-guided fractionations. Their structures were identified by spectral analysis as bis （4-hydroxybenzyl） ether （1）, p-hydroxyphenylethyl alcohol （2）, N-（4-hydroxyphenethyl） acetamide （3）, indole-3 carboxylic acid methyl ester （4）, dibenzo[b,e] [1,4]dioxine （5）, thymine （6）, cytosine deoxyribonucleoside （7） and 2, 3-butanediol （8）. These compounds were evaluated for their cytotoxic activities against K562 cell line with the SRB method for the first time. Compounds 2 and 4 showed cytotoxcities with IC50 values of 101.1 and 165.3 μolL^-1, respectively. All compounds were isolated from S. luteoverticillatum 11014 for the first time.

Expression and enzymatic characterization of a cold-adapted β-agarase from Antarctic bacterium Pseudoalteromonas sp.NJ21

An agar-degrading bacterium, designated as Pseudoalteromonas sp. NJ21, was isolated from an Antarctic sediment sample. The agarase gene aga1161 from Pseudoalteromonas sp. NJ21 consisting of a 2 382-bp coding region was cloned. The gene encodes a 793-amino acids protein and was found to possess characteristic features of the Glyco_hydro 42 family. The recombinant agarase （rAgal 161） was overexpressed in Escherichia coli and purified as a fusion protein. Enzyme activity analysis revealed that the optimum temperature and pH for the purified recombinant agarase were 30--40℃ and 8.0, respectively. rAga 1161 was found to maintain as much as 80% of its maximum activity at 10℃, which is typical of a cold- adapted enzyme. The pattern of agar hydrolysis demonstrated that the enzyme is an β-agarase, producing neoagarobiose （NA2） as the final main product. Furthermore, this work is the first proof of an agarolytic activity in Antarctic bacteria and these results indicate the potential for the Antarctic agarase as a catalyst in medicine, food and cosmetic industries.

Degradation of 2,6-di-tert-butylphenol by an isolated high-efficiency bacterium strain

An aerobic bacterium strain, F-3-4, capable of effectively degrading 2,6-di-tert-butylphenol(2,6-DTBP), was isolated and screened out from an acrylic fiber wastewater and the biofilm in the wastewater treatment facilities. This strain was identified as Alcaligenes sp. through morphological, physiological and biochemical examinations. After cultivation, the strain was enhanced by 26.3% in its degradation capacity for 2,6-DTBP. Results indicated that the strain was able to utilize 2,6-DTBP, lysine, lactamine, citrate, n-utenedioic acid and malic acid as the sole carbon and energy source, alkalinize acetamide, asparagine, L-histidine, acetate, citrate and propionate, but failed to utilize glucose, D-fructose, D-seminose, D-xylose, serine and phenylalanine as the sole carbon and energy source. The optimal growth conditions were determined to be: temperature 37℃, pH 7.0, inoculum size 0.1% and shaker rotary speed 250 r/min. Under the optimal conditions, the degradation kinetics of 2,6-DTBP with an initial concentration of 100 mg/L was studied. Results indicated that 62.4% of 2,6-DTBP was removed after 11 d. The degradation kinetics could be expressed by Eckenfelder equation with a half life of 9.38 d. In addition, the initial concentration of 2,6-DTBP played an important role on the degradation ability of the strain. The maximum initial concentration of 2,6-DTBP was determined to be 200 mg/L. Above this level, the strain was overloaded and exhibited significant inhibition.

Inhibition of spore germination of Ulva pertusa by the marine bacterium Pseudoalteromonas haloplanktis CI4

The effect of the bacterial strain C14 on the germination of spores from the green alga Ulva pertusa was assayed and it was found that the bacterial biofilm and cell-free supernatant strongly inhibited spore germination. In attempts to define the chemical nature of she antifouling substance in the supernatant of C14, the culture supernatants were tested for activity after heat treatment, enzymatic treatments, size fractionation, and separation into aqueous and organic fractions. Results suggest that this bacterium produces an extracellular component with specific activity toward algal spores that was heat-sensitive and between 3 and 10 kDa in molecular size. The exposure of the organic phase fraction to spores showed inhibitive effect on spore germination. Pronase and carboxypeptidase y did not significantly affect the activity of inhibitory component, suggesting that the component was not a protein or a peptide. The bacterium C14 was identified as Pseudoalteromonas haloplanktis based on the phenotypic characters and 16S rRNA gene analvsis.