人头皮微生物与相关头皮疾病的研究进展

近年来基于DNA测序和分子生物学技术的研究表明,头皮微生物特别是主要细菌和真菌与头皮生理指标、免疫状态、屏障功能等相关并且影响头皮健康。人头皮屑、脂溢性皮炎、斑秃、头皮型银屑病等头皮疾病常伴随微生物失衡。针对关键微生物及其相互平衡的干预可缓解或治疗疾病。本文总结了头皮微生物特别是细菌和真菌的研究概况、头皮微生物与头皮疾病,比较了目前的实验室研究方法,为头皮健康的维护、头皮产品开发和实验室研究方法提供参考。     

白马雪山云南黄芪与灰毛康定黄芪根际微生物物种多样性及抗生物膜活性菌株筛选

【背景】细菌生物膜是造成病原菌耐药性增强和持续感染的主要因素,但目前尚无针对抗菌膜的特效药物。特境植物根际微生物可产生大量具有提高宿主免疫功能的活性成分,极具抗生物膜药源开发潜力。【目的】了解滇西北高寒特境白马雪山分布的云南黄芪与灰毛康定黄芪植物根际微生物的物种多样性,并对可培养菌株进行抑菌与抗生物膜活性筛选。【方法】采用宏基因组技术结合传统微生物培养方法,对采自我国云南迪庆藏族自治州德钦县白马雪山的云南黄芪与灰毛康定黄芪的根际微生物进行物种多样性研究,并通过“孔板法”测定其可培养菌株发酵液乙酸乙酯粗浸膏的抗菌、抗生物膜活性。【结果】宏基因组测序结果显示,云南黄芪根际土壤样本中的微生物来自6门7纲8目8科9属10种,其中栖热菌属为优势菌群;灰毛康定黄芪根际土壤样本中的微生物来自6门8纲10目11科14属15种,其中慢生根瘤菌属为优势菌群。通过纯培养共获得145株可培养菌株,包括112株细菌和33株真菌。其中,云南黄芪根际细菌59株,共计16属35种,优势属为假单胞菌属和链霉菌属;根际真菌19株,共计4属5种,优势属为曲霉属;灰毛康定黄芪根际细菌53株,归属于16属29种,优势属为芽孢杆菌属与寡养单胞菌属;根际真菌14株,归属于3属4种,优势属为曲霉属。从不同种水平上选择51株细菌和7株真菌为代表菌株进行抗生素药源评估,发现5株细菌及1株真菌发酵液的乙酸乙酯粗浸膏具有中等至较强的抗革兰阳性菌活性,而且其中4株具有抗MRSA生物膜活性,最终确定了链霉属放线菌Streptomyces fulvissimus KTA1和曲霉属真菌Aspergillus fumigatus YNF5为潜力活性菌株。【结论】首次报道了滇西北地区高寒特境黄芪属植物根际微生物具有较好的物种多样性,而且具有一定的抗生素药用资源开发潜力。本研究对滇西北高寒特境特色植物来源的微生物资源开发利用与保护具有重要的借鉴意义。     

内蒙古贝加尔针茅草原不同利用方式土壤微生物功能多样性

基于Biolog-ECO技术,研究了贝加尔针茅草原在自由放牧、刈割和围封3种不同利用方式下土壤微生物群落功能多样性变化。结果表明:不同的利用方式能显著改变土壤微生物群落代谢活性,反映微生物活性的平均颜色变化率表现为围封>自由放牧>刈割,围封时土壤微生物群落代谢活性最高;不同的利用方式改变了土壤微生物群落多样性指数,自由放牧土壤微生物群落丰富度指数、均匀度指数和优势度指数均最高,围封次之,刈割最低。主成分分析结果表明:在自由放牧和刈割2种利用方式下土壤微生物群落碳源利用模式及代谢功能相似,而围封土壤微生物群落具有不同的碳源利用模式和代谢功能;糖类、氨基酸类和代谢中间产物及次生代谢物为土壤微生物利用的主要碳源。不同的利用方式改变了贝加尔针茅草原土壤微生物群落功能多样性。     

基于细胞色素c的胞外电子传递过程

电活性微生物具有独特的胞外电子传递功能,在地球化学循环和环境污染修复中起着重要作用。细胞色素c在电活性微生物胞外电子传递过程中扮演了重要角色,不仅参与直接电子传递途径,还参与电子媒介介导的间接电子传递。其电子传递功能不仅对地球环境中铁、锰、碳等元素的循环具有重要作用,还应用于能源生产、废水处理、生物修复等众多领域,具有良好的应用潜力。本文以电活性微生物的2个模式菌属(希瓦氏菌属和地杆菌属)为例,综述了电活性微生物将电子由胞内转移至胞外的方式和途径,详细阐述了细胞色素c在该胞外电子传递过程中的重要作用,总结了细胞色素c介导的胞外电子传递过程所涉及的分析方法,并对微生物胞外电子传递未来的研究方向提出了展望。     

金沙土遗址土壤细菌群落结构和推测的代谢特征

【背景】金沙土遗址被认为是3 200年前商周时期大型祭祀场所,具有重要的古文化和历史意义,目前金沙土遗址在物理、化学、生物等因素的影响下已出现不同程度的劣化,物理、化学因素的影响已有报道,而生物因素尚鲜有关注。【目的】研究金沙土遗址中微生物群落结构组成,解析微生物菌群活性及代谢特征,为金沙土遗址的科学保护提供依据。【方法】根据遗址目前的保存状况,从金沙土遗址采集具有代表性的土壤样品,所采区域样品的劣化程度依次为J4J3J2J1,应用Biolog平板法与PCR-DGGE技术对各样品中的微生物群落结构组成和代谢功能多样性进行研究。【结果】Biolog结果显示,随着金沙土遗址的劣化,各土壤样品中的微生物功能多样性存在较大差异,各样品的微生物群落代谢活性依次为:J2J3J4J1,表明随着土壤的劣化,微生物的代谢活性表现出增大的趋势。主成分分析结果反映出4个样品中的微生物碳代谢方式具有显著的变化,样品J2中的细菌群落对底物碳源利用种类最多,且偏好的碳源类型与其它样品存在明显的不同。PCR-DGGE图谱显示,金沙土遗址不同土壤样品中的细菌多样性和种群组成存在明显差异,在DNA和RNA水平上,各样品的微生物组成多样性依次为:J2J4J3J1。主成分分析结果显示,除了样品J1,劣化样品的细菌群落结构和活性细菌群落结构具有较高的一致性,表明随着金沙土遗址的劣化,土壤中微生物多样性呈现出上升趋势。DGGE图谱主要条带的测序结果表明,样品中主要的细菌类群归属于放线菌门(Actinobacteria)、酸杆菌门(Acidobacteria)、变形菌门(Proteobacteria)和异常球菌-栖热菌门(Deinococcus-Thermus),分属于7个属,在DNA和RNA水平上均能检测到红色杆菌属(Rubrobacter)和短波单胞菌属(Brevundimonas)。【结论】首次对金沙土遗址的细菌群落结构组成和功能进行分析,结果表明随着金沙土遗址劣化程度的增加,土壤微生物类群及功能多样性都随之增大,其中仅在劣化土壤样品中检出或者具有高表达活性的红色杆菌属、Tellurimicrobium、短状杆菌属细菌可能参与了土壤劣化过程,这为今后土遗址的科学保护提供了理论依据。     

胶州湾沉积物可培养细菌的多样性及其抑菌活性

【目的】海洋微生物在活性物质开发方面具有巨大的应用前景。为了研究胶州湾微生物的多样性和抑菌活性,选取胶州湾9个观测站点的沉积物进行了细菌多样性及抑菌活性分析。【方法】采用YPD和Z2216E培养基分离细菌,通过16S r RNA基因测序对分离菌株进行分类鉴定,继而采用牛津杯法考察分离菌株对7株指示菌的抑菌活性,最后用PCR方法筛选16株代表菌的PKSI、NRPS、CYP、Phz E和d TGD基因。【结果】从胶州湾沉积物中共分离出76株细菌,通过对16S r RNA序列分析,将其归为8个科11个属:节杆菌属、考克氏菌属、微球菌属、微杆菌属、假交替单胞菌属、Oceanisphaera、海单胞菌属、葡萄球菌属、芽孢杆菌属、硫胺素芽孢杆菌属和短芽孢杆菌属,其中分离细菌中有34株至少对1种指示菌有抑菌活性。所选取的16株菌均能检测到一种功能基因,且其中5株菌能同时检测到3种以上的功能基因。【结论】以上研究表明胶州湾海域有丰富的微生物资源,在生物活性次级代谢产物合成上有较大潜力。     

芽孢杆菌制剂对养殖前期罗非鱼池塘微生物群落代谢功能的影响

采用BiologECO微平板法检测了4口养殖前期投放或不投放芽孢杆菌制剂的罗非鱼池塘水体及底泥微生物群落代谢功能的变化情况,研究芽孢杆菌制剂对养殖前期罗非鱼池塘微生物群落代谢功能的影响。结果表明:芽孢杆菌制剂对底泥微生物群落的代谢活性、功能多样性及6大类碳源的利用有明显的促进作用,而对水体微生物群落代谢活性和功能多样性的影响不明显,但促进了水体微生物对6大类碳源的利用。研究结果证实,在养殖前期投放芽孢杆菌制剂有利于改善罗非鱼养殖池塘微生物群落的代谢功能,主要体现在提高底泥微生物群落的代谢功能上。     

UASB底部活性污泥中优势微生物群系及其对PTA生产废水的降解作用

处理对苯二甲酸(PTA)生产废水的上流式厌氧生物滤床(UASB)底部活性污泥中的微生物分析表明,其优势群系为专性好氧菌和兼性厌氧菌。经分离得到156株微生物,分别为假单胞菌属、微球菌属、葡萄球菌属、不动细菌属、芽孢杆菌属和酵母菌属。其中大部分菌株可以PTA生产废水中某些成分为唯一碳源而生长,而以菌株T6对PTA降解活性为最高。经鉴定,该菌与类产碱假单胞菌(Pseudomonas pseudoalcaligenes)很相似,但存在某些差异,尚需进一步研究确定。     

电活性微生物胞外聚合物的特征与应用

电活性微生物是一类能够通过直接接触、导电菌毛或氧化还原介质与电极或者其他细胞进行胞外电子传递的微生物。而在这个过程中,胞外聚合物(extracellular polymeric substances, EPS)扮演着重要的角色。EPS是微生物生长过程中通过细胞裂解、水解分泌的高分子聚合物的混合物,主要由蛋白质、多糖和腐殖质等物质组成。来自电活性微生物的EPS的不同组成成分和特性会对EPS的电活性以及电活性微生物胞外电子传递产生一定的影响,同时在环境应用方面发挥重要作用。因此,为了更全面了解电活性微生物EPS的电活性及其对电活性微生物胞外电子传递的作用,本文总体介绍了电活性微生物EPS的电活性的直接表征方法,再从组成成分、化学性质、物理性质和空间分布4个方面综述了其对EPS电活性的影响及其在电子传递中的作用,介绍了当前电活性微生物EPS在染料废水脱色、重金属吸附、有机污染物的生物转化和渗滤液管理等方面的环境应用,并从表征方法、试验规模和互作机理研究等角度展望了未来的研究方向。     

天然抗补体活性物质研究进展

补体系统的非正常激活可引起人体的多种疾病,包括类风湿性关节炎和老年性痴呆等,但目前还没有较好的抗补体制剂。化学合成的抗补体制剂成本高、选择性差、并能产生多种副作用,天然产物来源的抗补体活性成分引起了国内外学者的普遍关注。迄今为止,已经从动植物及微生物中分离出多种具有抗补体活性的物质,包括多糖、黄酮、甾体、皂苷、萜类、生物碱等。本文对近年来天然产物中具有抗补体活性的成分进行了综述,由于微生物易于培养及基因工程改良,而且产品质量容易控制,来自微生物的抗补体活性物质值得关注。     

N-Nitrosulfonamides: A new chemotype for carbonic anhydrase inhibition

A series of N¹-substituted aromatic sulfonamides was obtained by applying a selective sulfonamide nitration synthetic strategy leading to Ar-SO₂NHNO₂ derivatives which were investigated as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. Two human (h) hCA isoforms, the cytosolic hCA II and the transmembrane hCA IX, in addition to the fungal enzyme from Malassezia globosa, MgCA, were included in the study. Most of the new compounds reported selectively inhibited hCA IX over hCA II and at the same time showed effective MgCA inhibitory properties, with K_Is ranging between 0.22 and 8.09 μM. The N-nitro sulfonamides are a new chemotype with CA inhibitory effects. As hCA IX was recently validated as antitumor/antimetastatic drug target, its selective inhibition could be exploited for interesting biomedical applications. Moreover, due to the effective MgCAs inhibitory properties of the N-nitro sulfonamides, of considerable interest in the cosmetics field as potential anti-dandruff agents, the N-nitro sulfonamides may be considered as interesting leads for the design of more efficient compounds targeting fungal enzymes.     

Evaluation of the genotoxicity of the imidazole antifungal climbazole: comparison to published results for other azole compounds

Climbazole is an imidazole antifungal agent that can provide anti-dandruff benefits when incorporated into a shampoo matrix. A series of genotoxicity studies were performed to support the human safety of this azole antifungal drug. Climbazole was not mutagenic in the Salmonella typhimurium or Escherichia coli Ames assay and did not induce micronuclei in human lymphocytes. In the mouse lymphoma assay (MLA), climbazole was negative (non-mutagenic) with and without metabolic (S9) activation after a 4 h exposure; an increase in small colony mutants was observed without metabolic activation after a 24 h exposure at concentrations of 15 and 17.5 μg/mL. An in vivo mouse micronucleus test was negative up to a maximum tolerated dose (MTD) of 150 mg/kg climbazole administered orally. In the in vivo/in vitro unscheduled DNA synthesis assay, climbazole showed no evidence of DNA damage in the livers of rats at doses up to the MTD of 200 mg/kg orally. A toxicokinetic study was performed in mice with oral administration of [14C]-climbazole (150 mg/kg). Radioactivity (20.42 μg-equiv./g plasma) was detected 15 min after oral administration of [14C]-climbazole, and the peak concentration was 62.96 μg-equiv./g plasma at 8 h after dosing. The measured amounts of radioactivity in plasma, at all sample times from 15 min up to 24 h, exceeded the concentrations that induced increases in mutation frequency after 24 h exposure of mouse lymphoma cells in vitro (15 and 17.5 μg/mL). These observations lend support to the conclusion that climbazole does not present a genotoxic risk in vivo. Furthermore, these data are consistent with the published data for other azole antifungals that work by preventing the synthesis of ergosterol and, as a class, are generally non-genotoxic, except some isolated positive results of questionable significance. Collectively, these data are supportive of the view that climbazole does not present a genotoxic or carcinogenic risk to humans.     

Regeneration of the active zone at the frog neuromuscular junction

The active zone is a unique specialization of the presynaptic membrane and is believed to be the site of transmitter release. The formation of the active zone and the relationship of this process to transmitter release were studied at reinnervated neuromuscular junctions in the frog. At different times after a nerve crush, the cutaneous pectoris muscles were examined with intracellular recording recording and freeze-fracture electron microscopy. The P face of a normal active zone typically consists of two double rows of particles lined up in a continuous segment located opposite a junctional fold. In the initial stage of reinnervation, clusters of large intramembrane particles surrounding membrane elevations appeared on the P face of nerve terminals. Like normal active zones, these clusters were aligned with junctional folds. Vesicle openings, which indicate transmitter release, were seen at these primitive active zones, even though intramembrane particles were not yet organized into the normal pattern of two double rows. The length of active zones at this stage was only approximately 15% of normal. During the secondary stage, every junction was reinnervated and most active zones had begun to organize into the normal pattern with normal orientation. Unlike normal, there were often two or more discontinuous short segments of active zone aligned with the same junctional fold. The total length of active zone per junctional fold increased to one-third of normal, mainly because of the greater number of segments. In the third stage, the number of active zone segments per junctional fold showed almost no change when compared with the secondary stage. However, individual segments elongated and increased the total length of all active zone segments per junctional fold to about two-thirds of the normal length. The dynamic process culminated in the final stage, during which elongating active zones appeared to join together and the number of active zone segments per junctional fold decreased to normal. Thus, in most regions, regeneration of the active zones was complete. These results suggest that the normal organization of two double rows is not necessary for the active zone to be functional. Furthermore, localization of regenerating active zones is related to junctional folds and/or their associated structures.     

Estimation of the Total and Active Microbial Biomasses in Buried Subkurgan Paleosoils of Different Age

Microorganisms that were isolated from steppe soils buried below kurgans from 5800 to 750 years ago were analyzed for the completeness of isolation, total biomass (the sum of glucose-reactivated and resting microbial cells), and active biomass (metabolically active cells). The metabolic state of microbial communities in buried and modern background soils was estimated from the proportion of active and total biomasses. The paleosoils were found to be characterized by lower total and active biomasses and a lower proportion of active microorganisms as compared to the modern background soils. The age-dependent decrease in the content of active microorganisms in the microbial communities of paleosoils was not monotonic. For instance, the 4000-year-old paleosoil was characterized by a high total biomass and a relatively low content of active microorganisms, whereas the 1950-year-old paleosoil was characterized by a relatively low total biomass and a relatively high content of active microorganisms. This could reflect the temporal dynamics of paleoclimatic conditions in the geographic region under study.     

土壤活性有机碳的表征及其生态效应

土壤活性有机碳指在一定的时空条件下,受植物、微生物影响强烈、具有一定溶解性、在土壤中移动比较快、不稳定、易氧化、分解、易矿化,其形态,空间位置对植物、微生物来说活性比较高的那一部分土壤碳素。国外描述这一部分碳素的术语为有效碳、水溶性碳、易氧化碳、可矿...     

Estimation of the total and active microbial biomass in burial mound paleosoils of a different age

Microorganisms that were isolated from steppe soils buried below kurgans from 5800 to 750 years ago were analyzed for the completeness of isolation, total biomass (the sum of glucose-reactivated and resting microbial cells), and active biomass (metabolically active cells). The metabolic state of microbial communities in buried and modern background soils was estimated from the proportion of active and total biomasses. The paleosoils were found to be characterized by lower total and active biomasses and a lower proportion of active microorganisms as compared to the modern background soils. The age-dependent decrease in the content of active microorganisms in the microbial communities of palesoils was not monotonic. For instance, the 4000-year-old paleosoil was characterized by a high total biomass and a relatively low content of active microorganisms, whereas the 1950-year-old paleosoil was characterized by a relatively low total biomass and a relatively high content of active microorganisms. This could reflect the temporal dynamics of paleoclimatic conditions in the geographic region under study.     

Evidence for exchange of inhibitors which bind to the active site of trypsin. Displacement of one inhibitor with a competitive inhibitor

Two classes of inhibitors of trypsin (ED 3.4.21.4) have been studied, viz. active site-directed agents such as ovomucoid and active site titrants such as 4-methylumbelliferyl-4-guanidinobenzoate. The kinetics of beta-naphthyl-amidase inhibition by an active site-directed agent were markedly different from simultaneous assays of the availability of the active site towards active site titrants in the presence of the active site-directed agents. Analysis of these data indicated an exchange of active site-directed agent by subsequent addition of active site titrant. One class of trypsin inhibitor could be displaced by another from the trypsin active centre. Competitive chase experiments were designed to measure this exchange in which the active site-directed agent was first equilibrated with trypsin, then partially displaced by incremental additions of an active site titrant; the degree of active sites occupied by these two agents was then determined by active site titration with a second reagent.     

Maintenance of tone, role of arachidonate metabolites, and effects of sensitization in guinea pig trachea

A study was made of the mechanisms underlying production of resting active tension in guinea pig tracheal smooth muscle and the changes with active sensitization to ovalbumin. The same types of tissues were also analyzed as to their responses to arachidonate. Responses for each tissue were expressed in relation to a scale between zero active tension and maximum active tension in response to carbachol. A variety of selective and nonselective inhibitors of cyclooxygenase or 5-lipoxygenase were shown to affect active tension in a manner consistent with the conclusion that a cyclooxygenase product, probably prostaglandin F(PGF2 alpha) and not thromboxanes was chiefly responsible. The inhibition of active tension produced by cyclooxygenase inhibition was shown to be related to the initial active tension, such that tissues with greater resting active tension had greater reductions in tone. No differences of major importance were found as to the mechanisms underlying tone production in control and sensitized tissues. The tension changes in response to exogenous arachidonate were also found to be dependent on the initial level of active tension; when this was low, tension increased, when it was high, tension decreased or did not change. Effects of inhibitors on these responses were again consistent with the conclusion that primarily excitant prostaglandins, not thromboxanes, were produced. Some suggestive evidence for production of excitatory and inhibitory nonprostaglandin metabolites was obtained. No difference of major importance between control and sensitized tissues was observed in the magnitude or underlying mechanism of production of active tension.     

Sex-specific effects of gonadal steroids on conspecific odor preference in the rat

Effects of gonadal steroids on conspecific odor preference for either (1) sexually active male or active female, (2) sexually active or gonadectomized (gdx) males, (3) sexually active or gdx females, and (4) gdx males or gdx females were determined in male and female rats in a three-chamber apparatus. For the first test, gdx females were made sexually active by treatments with estradiol benzoate (EB) and progesterone (P), and sexually active males were selected by prior screening. Sexually active males and females preferred opposite-sex odor over same-sex odor. Odor of sexually active opposite-sex conspecifics was preferred over that of inactive ones. Immediately after the completion of the first test, sexually active males were gdx and females were left without hormonal treatment. Second and third tests were carried out 2 and 5 weeks after the first test. In the second test, gdx males preferred odor of sexually active males rather than that of receptive females (male-directed preference); in the third test, both males and females showed no preference when tested with four stimulus pairs. The final tests were carried out in gdx males with EB and P, and gdx females with 2-week exposure to testosterone (T). Males with EB and P showed a male-directed preference again, whereas T-treated females kept their own female preference. Injection of EB alone to gdx males did not induce any preference. The present study clearly demonstrated sex difference in conspecific odor preference. Although both male and female preferences depend on their circulating sex steroids, the direction of male preference is more susceptible to their hormonal states, compared to that of females.     

Dysregulated circRNAs in plasma from active tuberculosis patients

Endogenous circular RNAs (circRNAs) have been reported in various diseases. However, their role in active TB remains unknown. The study was aimed to determine plasma circRNA expression profile to characterize potential biomarker and improve our understanding of active TB pathogenesis. CircRNA expression profiles were screened by circRNA microarrays in active TB plasma samples. Dysregulated circRNAs were then verified by qRT‐PCR. CircRNA targets were predicted based on analysis of circRNA‐miRNA‐mRNA interaction. GO and KEGG pathway analyses were used to predict the function of circRNA. ROC curve was calculated to evaluate diagnostic value for active TB. A total of 75 circRNAs were significantly dysregulated in active TB plasma. By further validation, hsa_circRNA_103571 exhibited significant decrease in active TB patients and showed potential interaction with active TB‐related miRNAs such as miR‐29a and miR‐16. Bioinformatics analysis revealed that hsa_circRNA_103571 was primarily involved in ras signalling pathway, regulation of actin cytoskeleton, T‐ and B‐cell receptor signalling pathway. ROC curve analysis suggested that hsa_circRNA_103571 had significant value for active TB diagnosis. Circulating circRNA dysregulation may play a role in active TB pathogenesis. Hsa_circRNA_103571 may be served as a potential biomarker for active TB diagnosis, and hsa_circRNA_103571‐miRNA‐mRNA interaction may provide some novel mechanism for active TB.