一株苯酚降解菌的分离与鉴定

目的：筛选能高效降解苯酚的微生物,并进行初步鉴定。方法：从某焦化厂排水沟采集污泥,通过逐步驯化筛选苯酚降解菌株;利用形态观察、生理生化检测、16SrDNA序列分析进行初步鉴定。结果：筛选获得1株苯酚降解菌JDM-2—1,该菌能够以苯酚为惟一碳源,耐酚能力高达2200mg／L,在30℃和pH7．0条件下,42h内能将800mg／L的苯酚彻底降解;初步鉴定其为球形芽孢杆菌（Bacillus sphaericus）。结论：菌株JDM-2-1是一株高效降解苯酚的球形芽孢杆菌。     

两株苯酚降解菌的分离及降解特性的初步研究

从南昌钢铁公司焦化污水处理厂的活性污泥中分离出64株能降解苯酚的细菌,通过耐受性试验从中筛选出2株降解活性较高的苯酚降解菌,编号为F-38和F-64。研究表明:F-38和F-64都为G—菌,苯酚浓度越高,生长延滞期越长;两株菌降解苯酚基本发生在对数期,其对苯酚降解适宜条件为温度30℃,pH值8-9,通气有利于苯酚的降解。     

两株苯酚降解茵的分离及降解特性的初步研究

从南昌钢铁公司焦化污水处理厂的活性污泥中分离出64株能降解苯酚的细菌,通过耐受性试验从中筛选出2株降解活性较高的苯酚降解菌,编号为F-38和F-64。研究表明：F-38和F-64都为G-菌,苯酚浓度越高,生长延滞期越长;两株菌降解苯酚基本发生在对数期,其对苯酚降解适宜条件为温度30％,pH值8-9,通气有利于苯酚的降解。     

苯酚高效降解菌的筛选和降解特性研究

从东华理工学院北区原化学系排污口土壤中筛选到一株高效的苯酚降解细菌PS1。该菌为球菌,革兰氏染色阴性,能以苯酚为唯一碳源和能源生长。经16S rRNA基因部分序列分析PS1为Raoultella属菌株(Raoultella sp.strain PS1),其最高苯酚耐受和降解浓度在3500mg/L以上,当苯酚浓度为500mg/L和1000mg/L时,22h和32h可完全降解,在1500mg/L~3000mg/L时,32h~50h可完全降解,2500mg/L时降解速率最快,达78.1mg/h。通过正交试验得出该菌最适生长条件为25℃、pH6.5、葡萄糖500mg/L;最佳苯酚降解条件为20℃、pH7.0、葡萄糖500mg/L。     

一株苯酚降解菌的筛选、鉴定及其降解特性

本研究采用逐量分批驯化的方法,从造纸废水中分离得到一株能够以苯酚为唯一碳源生长的苯酚降解菌株F5-1.经形态观察、生理生化特性鉴定及16S rDNA序列分析,将该菌株鉴定为克雷伯菌(Klebsie-lla sp.).该菌株能够在7 h时完全降解初始浓度为100 mg/L的苯酚,降解苯酚主要发生在生长对数期;在pH 5.0～9.0,NaCl浓度0～80 g/L,温度20～40℃范围内,菌株F5-1均可有效降解初始浓度为100～1 200 mg/L的苯酚;能够耐受的最大苯酚浓度为1 500 mg/L.本研究结果表明,F5-1菌株对处理环境条件复杂的含酚废水具有潜在的应用前景.     

一株苯酚降解菌的鉴定及其降解特性

【目的】鉴定从某化工厂附近土样中分离到的一株耐高浓度苯酚的菌株T10,通过优化菌株的培养条件提高菌株对苯酚的降解率。【方法】根据菌株的形态、生理生化鉴定及16S rDNA测序分析确定其种属,以液体摇瓶培养菌株T10对苯酚的降解率为指标,对菌株的生长条件进行优化。【结果】菌株T10属恶臭假单胞菌(Pseudomonas putida)。添加葡萄糖、蛋白胨能有效缩短T10菌的生长周期,并使苯酚的降解率提高1.7倍。在菌体初始接种浓度为10%、温度为30°C、转速为180 r/min条件下,对初始苯酚浓度、pH和装液量的响应面优化结果如下:初始苯酚浓度3 000 mg/L、pH 7.5和装液量80 mL/250 mL,苯酚去除率最高可达到87.56%。【结论】T10菌能够耐受较高浓度的含酚废水,并且对苯酚有较强的降解能力,为下一步利用生物法处理含酚废水提供科学依据。     

苯酚高效降解菌的筛选和降解特性的研究

从天津市煤气厂的活性污泥中筛选、分离得到一株高效苯酚降解菌。经BIOLOG细菌自动鉴定系统及16SrDNA鉴定,该菌株为粪产碱杆菌(Alcaligenesfaecalis)。苯酚降解实验证实,该菌能在76h内完全降解1600mg·L-1的苯酚,并且随着苯酚浓度的增加,底物抑制作用增强,细胞得率下降。     

聚乙烯醇高效降解菌的筛选及降解特性研究

以聚乙烯醇为唯一碳源从环境中筛选获得了高效降解聚乙烯醇的微生物菌株XT11, 初步鉴定为假单胞菌属(Pseudomonas sp.)。对菌株Pseudomonas XT11的生长过程及PVA降解过程进行了研究, 发现该菌株在54 h内可将1 g/L的聚乙烯醇(PVA)降解。同时研究了温度、pH值及酵母膏浓度对该菌株降解PVA的影响, 结果表明其最适温度、pH值和酵母膏浓度分别为30℃、7.0和0.5 g/L。研究了PVA浓度对PVA降解率的影响, 发现随着PVA浓度的增大, PVA的降解率降低。     

一株高效羽毛降解菌的筛选与鉴定

将废弃羽毛制成氨基酸肥,从长期堆积腐烂羽毛的土壤中筛选出2株能降解羽毛的菌株。结果发现,其中X-Y4菌株降解羽毛的效率最高,经16S rDNA和生理生化分析鉴定为产吲哚金黄杆菌(Chryseobacterium indologenes)。以羽毛为唯一碳源和氮源,研究发酵条件对该菌株降解羽毛产可溶性蛋白的影响,通过单因素实验,确定了该菌株最优发酵条件：羽毛填量10 g/L、转速200 r/min、初始pH 9.0、接种量2%、温度35℃,在此条件下,可溶性蛋白产量为(173.27±2.95)μg/mL。将该羽毛降解菌制得的氨基酸肥分别通过叶面喷洒和灌根施加于黑叶葵扇白菜盆栽中,并对其基本指标进行测定分析。结果表明：0.2 L/m²灌根施加,对黑叶葵扇白菜的促生效果最明显,其鲜质量增加了63.48%。     

一株苯酚降解菌的筛选及其降解特性的初步研究

苯酚是一种严重污染物,目前的化学降解方法存在众多弊端,生物处理方法越来越受到重视。从胜利油田河口采油厂的飞雁滩油田土壤样品中分离,得到一株能够利用并降解苯酚的菌株P2。该菌株能够在以苯酚为唯一碳源和能源的培养基上生长,经BIOLOG细菌自动鉴定系统及16SrDNA鉴定,该菌株为类产碱假单胞菌（Pseudomonas pseudoalcaligenes）。通过苯酚羟化酶特异性引物的设计,从该菌株扩增出苯酚羟化酶大亚基（LmPH）基因,该基因片段编码对苯酚有催化活性的多肽。苯酚降解实验证实,该菌能在30℃192h内完全降解500mg／L的苯酚,Cu^2＋严重抑制该菌株对苯酚的降解,但碱性环境有利于其对苯酚的降解。     

两株具有芘降解功能的植物内生细菌的分离筛选及其特性

从植物体内筛选具有多环芳烃(PAHs)降解功能的内生细菌并定殖于植物体,有望有效地去除植物体内PAHs,从而减低植物污染风险。采用富集培养法,从长期受PAHs污染的植物体内分离筛选出2株能以芘为唯一碳源和能源生长的内生细菌BJ03和BJ05,经形态观察、生理生化特性及16S rDNA序列同源性分析,将2株菌分别鉴定为不动杆菌属(Acinetobacter sp.)和库克氏菌属(Kocuria sp.)。并研究了2株内生细菌对芘的降解能力及环境条件对其降解芘的影响。结果表明,菌株BJ03和BJ05在以浓度为50 mg/L的芘为唯一碳源生长时,于30℃、150 r/min摇床培养15 d后,对芘的降解率分别为65.0%和53.3%。2株菌在pH值(6.0—9.0)、温度(25—40℃)和盐浓度(NaCl含量为0—15 g/L)条件下生长良好,且皆为好氧生长,通气量越大,菌株生长越旺盛,对芘的降解能力越强。添加C、N源可有效促进菌株BJ03和BJ05的生长,加速其对芘的降解速率。当外加C源为蔗糖、N源为酵母膏时,2株菌在30℃摇床培养4 d后,对芘的降解率分别高达71.1%和55.3%。2株菌的细胞表面疏水率最大分别为93.7%和43.9%,对四环素和利福平敏感,而对其它多种抗生素具有较强的抗性。     

Bioaugmentation and coexistence of two functionally similar bacterial strains in aerobic granules

The survival of the inoculated microbial culture is critical for successful bioaugmentation but impossible to predict precisely. As an alternative strategy, bioaugmentation of a group of microorganisms may improve reliability of bioaugmentation. This study evaluated simultaneous bioaugmentation of two functionally similar bacterial strains in aerobic granules. The two strains, Pandoraea sp. PG-01 and Rhodococcus erythropolis PG-03, showed high phenol degradation and growth rates in phenol medium, but they were characterized as having a poor aggregation activity and weak bioflocculant-producing and biofilm-forming abilities. In the spatially homogeneous batch conditions, strain PG-01 with higher growth rates outcompeted strain PG-03. However, the two strains could stably coexist in the spatially heterogeneous conditions. Then the two strains were mixed and bioaugmented into activated sludge in two sequencing batch reactors, which were operated with the different settling times of 5 and 30 min, respectively. Aerobic granules were developed only in the reactor with a settling time of 5 min. Fluorescence in situ hybridization and denaturing gradient gel electrophoresis showed that the two strains could coexist in aerobic granules but not in activated sludge. These findings suggested that the compact structure of aerobic granules provided spatial isolation for coexistence of competitively superior and inferior strains with similar functions.     

Acoustic-resonance spectrometry as a process analytical technology for rapid and accurate tablet identification

This research was performed to test the hypothesis that acoustic-resonance spectrometry (ARS) is able to rapidly and accurately differentiate tablets of similar size and shape. The US Food and Drug Administration frequently orders recalls of tablets because of labeling problems (eg, the wrong tablet appears in a bottle). A high-throughput, nondestructive method of online analysis and label comparison before shipping could obviate the need for recall or disposal of a batch of mislabeled drugs, thus saving a company considerable expense and preventing a major safety risk. ARS is accurate and precise as well as inexpensive and nondestructive, and the sensor, is constructed from readily available parts, suggesting utility as a process analytical technology (PAT). To test the classification ability of ARS, 5 common household tablets of similar size and shape were chosen for analysis (aspirin, ibuprofen, acetaminophen, vitamin C, and vitamin B12). The measures of successful tablet identification were intertablet distances in nonparametric multidimensional standard deviations (MSDs) greater than, 3 and intratablet MSDs less than 3, as calculated from an extended bootstrap erroradjusted single sample technique. The average intertablet MSD was 65.64, while the average intratablet MSD from cross-validation was 1.91. Tablet mass (r²=0.977), thickness (r²=0.977), and density (r²=0.900) were measured very accurately from the AR spectra, each with less than 10% error. Tablets were identified correctly with only 250 ms data collection time. These results demonstrate that ARS effectively identified and characterized the 5 types of tablets and could potentially serve as a rapid high-throughput online pharmaceutical sensor. Published: March 17, 2006     

Degradation of 3-chlorobenzoate and phenol singly and in mixture by a mixed culture of two ortho-pathway-following <Emphasis Type="Italic">Pseudomonas</Emphasis> strains

The compatibility and efficiency of two ortho-cleavage pathway-following pseudomonads viz. the 3-chlorobenzoate (3-CBA)-degrader, Pseudomonas aeruginosa 3mT (3mT) and the phenol-degrader, P. stutzeri SPC-2 (SPC-2) in a mixed culture for the degradation of these substrates singly and simultaneously in mixtures was studied. Another phenol-degrading strain, Pseudomonas sp. SoPC-5 (SoPC-5) that utilizes a meta-cleavage mode also was tried in co-culture with 3mT. The former combination was found to be a better degrader of both the substrates when present alone. But, with inoculum levels of 0.15 mg cell dry wt each of 3mT/SPC-2 or 3mT/SoPC-5 growth with 2 mM each of 3-CBA and phenol was slow with a lag of 24 h and degradation being incomplete. However, with higher inocula in the ratios 1:1, 1:2, and 2:1, i.e., 0.3 + 0.3, 0.3 + 0.6, and 0.6 + 0.3 mg cell dry wt of 3mT and SPC-2, respectively complete degradation of both the substrates occurred. Degradation of 3-CBA was complete with the release of stoichiometric amounts of chloride (Cl⁻) when concentrations of phenol/3-CBA were varied as 2:2, 2:4, and 4:2 mM, i.e., even when the concentration of the more toxic co-substrate 3-CBA was higher than phenol effective simultaneous degradation occurred at the inoculums ratio of 1:1 (0.3 mg dry cell wt. of each strain). These studies clearly indicated the better suitability of ortho-cleavage-utilizing strains as partners in a mixed culture than those follow different modes.     

一株氯霉素降解细菌的分离鉴定与代谢特性研究

微生物是介导环境中氯霉素降解转化的主要驱动者,但高效降解矿化菌株资源匮乏,氧化反应介导的代谢途径不清。为研究微生物介导下氯霉素的环境归趋过程,为氯霉素污染环境强化修复提供菌株资源,文中以受氯霉素污染的活性污泥为接种源,首先富集获得一个由红球菌Rhodococcus主导 (相对丰度>70%) 的氯霉素高效降解菌群,并从中分离获得一株能够高效降解氯霉素的菌株CAP-2,通过16S rRNA基因分析鉴定为红球菌Rhodococcus sp.。菌株CAP-2能在不同营养条件下高效降解氯霉素。基于菌株CAP-2对检测到的代谢产物对硝基苯甲酸和已报道的代谢产物对硝基苯甲醛和原儿茶酸的生物转化特征,提出其降解途径是由氯霉素侧链氧化断裂生成对硝基苯甲醛,进一步氧化为对硝基苯甲酸的新型氧化降解途径。该菌株对于氯霉素分解代谢的分子机制研究以及受氯霉素污染环境的原位生物修复应用具有巨大潜力。     

New and highly efficient methodology for screening high-yield strains of cytotoxic deacetylmycoepoxydiene (DAM)

Aims: To establish a highly efficient methodology for screening high yield strains of cytotoxic deacetylmycoepoxydiene (DAM), to meet the need of research on its mechanism of anti‐tumor properties and in vivo toxicity studies. Methods and Results: A simple, sensitive, and highly repetitive screening procedure ‘Antimicrobial‐TLC–HPLC’ (ATH) was established for the rapid obtaining of high‐yielding DAM mutants to replace the time and labor intensive anti‐tumor activity assay (MTT). With this ATH method, four highly yielding DAM mutants were selected out of 5000 total mutants, one of which, M4‐143, showed yields of more than 300 times (250·3 mg l^?1) that of the parent strain A123. Conclusions: The ATH method developed in this work has proven to be both economical and highly efficient with the screening of 1200 mutants in a one week time period, thusly shortening the expenditure of time and labor, without missing a single high‐yield mutant. Due to these characteristics, it is superior to other HTS screening methods described in earlier literature. The mutant M4‐143 has a good genetic stability and can be used for further research. Significance and Impact of the Study: This ATH screening method is not only perfect for screening high‐yield DAM mutants, but also, it is suitable to screen the strain libraries for those strains that have the ability to produce natural metabolites with antitumor activity.     

Annexin-A6 presents two modes of association with phospholipid membranes. A combined QCM-D, AFM and cryo-TEM study

Annexins are soluble proteins that bind to biological membranes in a Ca²⁺-dependent manner. Annexin-A6 (AnxA6) is unique in the annexin family as it consists of the repeat of two annexin core modules, while all other annexins consist of a single module. AnxA6 has been proposed to participate in various membrane-related processes, including endocytosis and exocytosis, yet the molecular mechanism of association of AnxA6 with biological membranes, especially its ability to aggregate membranes, is still unclear. To address this question, we studied the association of AnxA6 with model phospholipid membranes by combining the techniques of quartz crystal microbalance with dissipation monitoring (QCM-D), (cryo-) transmission electron microscopy (TEM) and atomic force microscopy (AFM). The properties of membrane binding and membrane aggregation of AnxA6 were compared to two reference systems, annexin A5 (AnxA5), which is the annexin prototype, and a chimerical AnxA5-dimer molecule, which is able to aggregate two membranes in a symmetrical manner. We show that AnxA6 presents two modes of association with lipid membranes depending on Ca²⁺-concentration. At low Ca²⁺-concentration (60–150 μM), AnxA6 binds to membranes via its two coplanar annexin modules and is not able to associate two separate membranes. At high Ca²⁺-concentration (2 mM), AnxA6 molecules are able to bind two adjacent phospholipid membranes and present a conformation similar to the AnxA6 3D crystallographic structure. Possible biological implications of these novel membrane-binding properties of AnxA6 are discussed.     

Molecular cloning, identification, and chromosomal localization of two MADS box genes in peach （Prunus persica）

MADS box proteins play an important role in floral development. To find genes involved in the floral transition of Prunus species, cDNAs for two MADS box genes, PpMADS1 and PpMADS10, were cloned using degenerate primers and 5'- and 3'- RACE based on the sequence database of P. persica and P. dulcis. The full length of PpMADS1 eDNA is 1, 071bp containing an open reading frame (ORF) of 717bp and coding for a polypeptide of 238 amino acid residues. The full length of PpMADS10 cDNA is 937bp containing an ORF of 633bp and coding for a polypeptide of 210 amino acid residues. Sequence comparison revealed that PpMADS1 and PpMADS10 were highly homologous to genes AP1 and PI in Arabidopsis, respectively. Phylogenetic analysis indicated that PpMADS1 belongs to the euAP1 clade of class A, and PpMADS10 is a member of GLO/PI clade of class B. RT-PCR analysis showed that PpMADS1 was expressed in sepal, petal, carpel, and fruit, which was slightly different from the expression pattern of AP1; PpMADS10 was expressed in petal and stamen, which shared the same expression pattern as PI. Using selective mapping strategy, PpMADS1 was assigned onto the Bin 1:50 on the G1 linkage group between the markers MCO44 and TSA2, and PpMADS10 onto the Bin 1:73 on the same linkage group between the markers Lap-1 and FGA8. Our results provided the basis for further dissection of the two MADS box gene function.     

一株海洋低温葡萄糖氧化酶菌株的筛选、鉴定及部分酶学性质

【目的】从海洋样品中分离筛选出产葡萄糖氧化酶菌株。【方法】采用双层平板筛选法进行初筛、复筛确定一株酶活较好的菌株,命名为GOD2(Glucose oxidase)。通过形态学、生理生化特征及16S rRNA基因序列分析研究其分类地位,并对其产生的葡萄糖氧化酶进行分离纯化和部分酶学性质的研究。【结果】细菌GOD2为产葡萄糖氧化酶菌株且遗传稳定,初步鉴定该菌株为假单胞杆菌(Pseudomonas migulae),其所产酶最适反应温度为20°C,热稳定性较差,40°C剩余相对酶活80%;超过40°C酶活力迅速下降。【结论】GOD2是一株极具研究价值的产低温葡萄糖氧化酶菌株。目前没有关于利用该菌生产葡萄糖氧化酶的报道。     

强化龙葵富集镉根际促生菌的分离、筛选与鉴定

【背景】植物-微生物联合修复土壤重金属污染日渐兴起,获取与超富集植物高效互作的微生物是实现联合修复技术进步的关键。龙葵在镉农田污染修复中广泛应用。【目的】筛选可促进龙葵生长及富集镉的耐镉根际促生菌。【方法】从龙葵根际土分离耐镉菌株,筛选具有良好促生特性的菌株,水培试验考察镉胁迫下菌株对植物生长及镉富集能力的影响,确定可促进龙葵生长及富集镉的微生物菌株,通过生理生化特性和16S rRNA基因序列分析进行菌株的初步鉴定。【结果】分离得到NT1、AXY1、AW2和AW1四株强化龙葵富集镉促生菌,经鉴定分别为Lysinibacillus sp.、Beijerinckia fluminensis、Achromobacter animicus和Herbaspirillum huttiense。上述菌株均可有效促进龙葵生长,增加其株高和干物质积累,提高地上部镉富集量。其中,NT1可使株高、地上部干重分别增加31.33%和62.65%,AW2可使地上部镉富集量增加37.29%。【结论】筛选所得菌株可为提高植物修复效率提供实践依据,为研制田间施用生态功能菌剂做铺垫,用于农田镉污染的微生物-龙葵联合原位修复。