巴氏芽孢杆菌矿化作用机理及应用研究进展

本文介绍了具有诱导碳酸钙矿化功能的巴氏芽孢杆菌及其矿化核心酶脲酶的结构与功能,较为系统地综述了巴氏芽孢杆菌矿化作用的生物机制,简要介绍了国内外多领域关于巴氏芽孢杆菌矿化应用的研究现状及典型应用案例,并探讨了相应微生物矿化技术在特定环境下的应用前景及在未来应用中可能存在的不足之处,相关分析论述对进一步推进微生物矿化技术的应用具有较为重要的意义.     

基于不同氮源培养条件的巴氏芽孢杆菌脲酶功能转录组分析

巴氏芽孢杆菌是源于土壤的革兰氏阳性菌,人们利用其高效的脲酶活性诱导产生碳酸钙的现象开发了多种应用场景.然而,巴氏芽孢杆菌的生物矿化相关代谢机制还不够明确,尤其是对在矿化作用中发挥核心作用的脲酶基因结构、表达调控机制及关联代谢等方面的研究相对较少.当前,巴氏芽孢杆菌应用研究中面临的矿化反应不可控性及不稳定性等问题都源于脲酶代谢机制的研究匮乏.因此,进一步揭示巴氏芽孢杆菌脲酶的基因信息、表达调控机制及相关代谢机理迫在眉睫.本文通过转录组测序,对比了4种培养条件下巴氏芽孢杆菌的生长情况和基因表达情况,解析了脲酶的代谢机制,结果进一步证明ATP合成与脲酶表达及尿素水解相关联,最终预测了脲酶的双操纵子结构.     

农业上的应用

生物防r治951D11 ’苏云尊孢杆曹G7的抑■活性[俄]/Konstsnti—noYa,G.E.…/Biotekhnologiya..1994,(1).一15～18[译自DBA,1994,13(16).94—09248] 苏云金芽孢杆菌G7菌株及其培养液(cf 1)具有抗苏云金芽孢杆菌苏云金HD2、苏云金芽孢杆菌tolworthy 12、枯草杆菌366、蜡状芽孢杆菌569、胃八叠球菌和黄色八叠球菌的活性。菌株HD2只对蜡状芽孢杆菌和苏云金芽孢杆菌tolworthy有活性。热处理可消除G7 cf l对除八叠球菌外其它所有细菌的活性并可去除IPID2的全部活性.链霉蛋白酶可去除HD2的全部活性,但只阻断G7对八叠球菌的活性。有数据…     

球形赖氨酸芽孢杆菌(Lysinibacillus sphaericus)和嗜冷芽孢八叠球菌(Sporosarcina psychrophila)介导形成白云石晶体

【目的】白云石(Dolomite)是一种含有钙镁的碳酸盐矿物[CaMg(CO3)2],广泛存在于陆地和海洋等环境并常与油气埋藏共存。尽管白云石(或岩)的发现已经有三百多年的历史,但是对白云石的成因仍然没有定论,地质学上称之为"白云石之谜"。20世纪90年代Vasconcelos C.提出了"微生物白云石模型",为白云石成因的研究带来了新的思路。但是这一模型并不完善,白云石的形成与所介导的微生物生理状态以及环境参数之间的关系不明确。另外,所有报道的实验都是在地表压强条件下进行,无法表征自然界中白云石所处的高压环境。本研究中引入压力这一环境参数,结合菌株本身生理特性参数,综合考察多重因子对微生物介导形成白云岩的影响。【方法】利用球形赖氨酸芽孢杆菌(Lysinibacillus sphaericus)和嗜冷芽孢八叠球菌(Sporosarcina psychrophila)两株具有尿素水解活性的细菌作为生物材料,在不同的温度(15°C和30°C)压强(常压和20 MPa)氧气浓度(常压好氧条件和常压微氧条件)不同的尿素水解活性下进行生物矿化实验。通过SEM(扫描电子显微镜)和EDS(X射线能谱分析)相结合的方法观察沉淀物形貌和矿物成分构成。通过XRD(X射线衍射分析)定性测定碳酸盐矿物沉淀物的种类。【结果】球形赖氨酸芽孢杆菌和嗜冷芽孢八叠球菌在实验中所设计的所有矿化条件下都能够介导形成碳酸盐矿物沉淀。XRD和SEM检测均证实球形赖氨酸芽孢杆菌在30°C的20 MPa微氧条件下能够介导形成不规则菱面型和椭球型白云石。高压条件更有助于白云石的形成。除了白云石晶体,实验中还观察到有其他矿物(如方解石,碳氢镁石,钙镁碳酸石等)。【结论】实验证实球形赖氨酸芽孢杆菌和嗜冷芽孢八叠球菌具有矿化能力,特别是球形赖氨酸芽孢杆菌具有介导形成白云石的能力。微生物介导形成的碳酸盐矿物组分受到微生物的代谢活性以及温度、压力等生物矿化实验条件控制。这一研究结果帮助完善"微生物白云石模型",为解释白云石的深部成因提供数据支持。     

巴氏甲烷八叠球菌BTC菌株的鉴定

本文报告了巴氏甲烷八叠妹菌BTC菌株的鉴定结果。该菌株在生活周期内均呈大小不等的团块聚集,8个不规则的球形细胞聚集在一起是团块构成的基本单位,未见单细胞阶段。在紫外线照射下,菌落荧光为蓝绿色,菌体荧光为蓝白色,活细胞或干制标本均可发出荧光。在以甲醇为生长基质时,其倍增时间为9．85h。可以利用甲醇,乙酸钠、三甲胺及H2／CO：为碳源;不能利用甲酸、乙醇、丙醇和丁醇等。最适生长pH为7．0。DNA的G+c mol％含量为41.5％。该菌株与巴氏甲烷八叠球菌近似或相同,而与马氏甲烷八叠球菌不同。其倍增时间较巴氏甲烷八叠球菌227菌株短,DNA中G+C mol％含量也与巳报道过的各菌株有 所差别,所以定名为巴氏甲烷八叠球曲BTC菌株(Methanosarcina barketi BTC)。     

凤丹丹皮酚抗菌作用的研究

用钢管法、滤纸法、挖孔法对凤丹丹皮酚的抗菌作用进行了研究,结果表明：凤丹丹皮酚对黄色八叠球菌、福氏知杆菌、枯草芽孢菌、金黄色葡萄球菌、大肠杆菌等五种供试细菌均有较强的抑制作用,尤其是黄色八叠球菌最为敏感;三种方法中挖孔法效果最佳。     

一株羽毛降解菌的分离与鉴定

【目的】从土壤中分离并鉴定羽毛降解菌,测定其生长最适温度及起始pH,并观察酶活动态。【方法】采用系列稀释法和选择培养基法筛选目的菌株,基于16S rRNA基因序列及Biolog方法鉴定其分类地位,利用全自动生长曲线分析仪监测菌株的最适生长条件,并通过测定蛋白水解活性观察其酶活动态。【结果】从混合羽毛的土壤样品中筛选到一株羽毛降解菌,命名为菌株GIMN1.015,初步判定该菌株属于芽孢八叠球菌属(Sporosarcina)。最适生长pH为9.0,温度为30°C。蛋白水解活性最高值出现在培养后96 h。【结论】菌株GIMN1.015在利用羽毛角蛋白资源中具有潜在的应用价值。这是芽孢八叠球菌在羽毛降解方面的首次报道。     

粘细菌CS211的分离纯化、生物学特征及其抗生活性初步研究

从采白成都市郊森林的土壤中分离纯化到二株粘细菌CS262和CS211。二株粘细菌在琼脂平板上表现出相互抑制子实体发育的拮抗作用。CS211菌株对蜡状芽孢杆菌,藤黄八叠球菌,枯草芽孢杆菌,金黄色葡萄球菌具有很强的抑制作用。采用非极性大孔树脂吸附和TIC方法对抗菌活性物质作了初步研究。     

Surfactin的生产及在石油工业的应用研究进展

表面活性素(surfactin)是由枯草芽孢杆菌代谢产生的环脂肽类生物表面活性剂。Surfactin具有卓越的表/界面活性,在石油化工、生物医疗、农业和食品工业等领域具有良好的应用前景,被认为是最具潜力的生物表面活性剂之一。但高昂的生产成本以及使用成本限制了surfactin的规模化应用。本文中,笔者对surfactin的发酵生产研究及其在石油化工领域中的应用研究进行综述,并对surfactin的发酵生产及应用研究前景进行展望。     

两种合成抗菌肽的结构及抗菌作用机理

为深入了解两种新型人工抗菌肽mytilin-derived-peptide-1 (MDP-1) 和mytilin-derived-peptide-2 (MDP-2) 的溶液结构和抗菌机理并探讨两种抗菌肽之间活性差异的结构基础,采用二维核磁共振技术 (2-D NMR) 研究MDP分子的溶液结构;采用透射电镜技术 (Transmitted electron microscopy,TEM) 研究MDP分子对于大肠杆菌和藤黄叠球菌的作用机理。研究结果表明,MDP-1和MDP-2均采取了典型的β-发夹结构,其分子表面具有明显的疏水斑片,其分子中碱性氨基酸突出于分子表面;经MDP分子处理后的大肠杆菌以及藤黄叠球菌均出现细胞壁或细胞膜结构被破坏,并出现膜壁分离以及细胞质内缩现象。我们认为,MDP-1和MDP-2分子中的碱性氨基酸有助于MDP结合细菌表面的带负电荷的基团,同时其分子表面的疏水斑片有助于其插入到细菌细胞膜内;其疏水斑片面积以及碱性氨基酸在分子表面的拓扑结构差异是MDP-1和MDP-2活性差异的主要原因;电镜实验结果表明MDP-1和MDP-2的主要靶标是细菌细胞壁以及细胞膜;上述研究为深入了解MDP分子的结构与功能的关系以及将来基于MDP分子的药物研发奠定了基础。     

白蚁与动物及微生物的共生类型及其机制

综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生（宾主共栖和异种共栖）、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌（原生动物、细菌、真菌和放线菌）和外生菌（蚁巢伞菌等）间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用（如纤维素酶）及今后研究物种间的协同进化提供了基础资料。     

New amino-dithiaphospholanes and phosphoramidodithioites and their rhodium and iridium complexes

New sulfur derivatives of phosphoramidite ligands were synthesized and the impact of the sulfur unit on the spectroscopic properties of their rhodium and iridium complexes was investigated. The new ligands Bn₂NPSCH₂CH₂S^a(P-S^a) (Bn = benzyl, 4), Bn₂NPSCHCHS^a(CH₂)₃C^aH₂(P-S^a)(C^a-S^a) (6) and Bn₂NP(4-XC₆H₄OMe)₂ (X = S, 7a; X = O, 7b) were converted to the rhodium and iridium complexes trans-[Rh(CO)Cl(L)₂] (L = 4, 6, 7), [RhCl(COD)(L)] (L = 4, 6, 7), [IrCl(COD)(7a)] and [IrCl₂Cp∗(6)]. For comparison, some phosphoramidite complexes of these formulations also were synthesized. The new metal complexes were spectroscopically analyzed. For the carbonyl complexes, the ν_CO IR stretching frequencies were lower than for the corresponding phosphite and phosphoramidite ligands. The ¹J_PRh coupling constants for the rhodium complexes with the new ligands were also smaller than for the respective phosphoramidite and phosphite complexes. Finally, the ¹J_PSe coupling constants of the selenides of the new ligands were lower than those of the phosphoramidite ligands but higher than for PPh₃. The spectroscopic data reveal that the new thio ligands 4, 6 and 7a are more electron donating than phosphites and phosphoramidites but less electron donating than PPh₃.     

Astrocytes and Synaptosomes Transport and Metabolize Lactate and Acetate Differently

Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes.     

Rapporteur report: Basics and technology and metrology and standards

The first and second sessions of the Workshop focussed on the basics of ultrasound and infrasound, their applications in both industry and medicine, and metrology and protection standards for ultrasound applications.     

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion

To elucidate accumulation of minerals in human iliac arteries with aging, the content of minerals was analyzed by inductively coupled plasma atomic emission spectrometry. Bilateral common, internal, and external iliac arteries of 16 men and 8 women, ranging ages from 65 to 93 yr, were examined. It was found that an extremely high accumulation of calcium and phosphorus occurred in the common iliac artery at old age, being higher than that of the internal and external iliac arteries. It should be noted that the accumulation of calcium and phosphorus is the highest in the common iliac artery among the human arteries examined to date. Regarding sexual differences, the content of calcium and phosphorus in the common and internal iliac arteries was higher in women than in men, whereas their content in the external iliac artery was lower in women than in men.     

Prostaglandin and thromboxane production by human and guinea-pig macrophages and leucocytes

The ability of partially purified human and guinea-pig haematogenous cell populations, when cultured in vitro, to metabolise arachidonic acid (AA) has been studied. Supernatants from 24 hour cell culture have been subjected to analysis for products of AA metabolism by gas chromatography with electron-capture detection.The cell types studied were human peripheral blood monocytes (both glass adherent and non-adherent), neutrophils, eosinophils and leukemic leucocytes; thoracic duct lymphocytes and lung alveolar macrophages. From the guinea-pig, induced and non-induced macrophage or neutrophil enriched peritoneal exudate populations, lymph node cells, peritoneal eosinophils and peripheral blood platelets were examined. Supernatants were assayed for the presence of PGE₂, PGD₂, PGF_2α, TXB₂ and 6-keto-PGF_1α. In all types studied PGE₂ and TXB₂ were the major products formed. The identification of PGE₂ and TXB₂ was confirmed by GC/MS with multiple ion monitoring.The results have been compared with other reports and their possible significance discussed in relation to the proposed role of prostaglandins as mediators and modulators in immunopathology.     

Chemokines and cytokines: axis and allies in asthma and allergy

Allergic asthma can be precipitated by many factors. For the atopic person, fungus, pollen, dust mites, cockroach antigens, and diesel exhaust are all agents that may trigger an allergic attack. Cytokines and chemokines are integral mediators of fungal asthma. From the earliest time points, they recruit and activate the cells required for the clearance of fungus as well as being critical factors involved in the immunopathology of this disease. In the final analysis, it is clear that these mediators can act to the benefit or the detriment of the host.     

Oxidation and nitration of ribonuclease and lysozyme by peroxynitrite and myeloperoxidase

In spite of the many studies on protein modifications by reactive species, knowledge about the products resulting from the oxidation of protein-aromatic residues, including protein-derived radicals and their stable products, remains limited. Here, we compared the oxidative modifications promoted by peroxynitrite and myeloperoxidase/hydrogen peroxide/nitrite in two model proteins, ribonuclease (6Tyr) and lysozyme (3Tyr/6Trp). The formation of protein-derived radicals and products was higher at pH 5.4 and 7.4 for myeloperoxidase and peroxynitrite, respectively. The main product was 3-nitro-Tyr for both proteins and oxidants. Lysozyme rendered similar yields of nitro-Trp, particularly when oxidized by peroxynitrite. Hydroxylated and dimerized products of Trp and Tyr were also produced, but in lower yields. Localization of the main modified residues indicates that peroxynitrite decomposes to radicals within the proteins behaving less specifically than myeloperoxidase. Nitrogen dioxide is emphasized as an important protein modifier.