大气细菌粒子浓度的时间分布特征及最佳采样时间的研究

用ＭＦ－４５型和ＨＴＫ－２０１型空气微生物采样器分别在北京、天津和沈阳三地观测了不同季节和一天中大气细菌粒子的浓度及其变化。结果表明：京、津二地春季大气细菌粒子浓度高，分别为２０５３个／ｍ３和２５５６个／ｍ３；夏季低，分别为９９５个／ｍ３和１０６４个／ｍ３。沈阳秋季大气细菌粒子浓度高，为１０１０８个／ｍ３；冬季低，为１２９４个／ｍ３。一天中，大气细菌粒子浓度呈双峰型变化，６：００～７：００和１８：００时大气细菌粒子浓度高，１１：００～１３：００和１：００～２：００时大气细菌粒子浓度低。根据大气细菌粒子浓度的季节变化和一天中大气细菌粒子浓度的时间分布特征，经过京、津、沈三地一天中分别１２次、８次、６次和４次不同采样时间组合的大气细菌粒子浓度的数理统计分析，大气细菌粒子浓度的监测拟集中在一年冬、春、夏、秋四季的中间月份，即１月、４月、７月、１０月进行；一天中采样８次的时间序列可为７：００、１０：００、１３：００、１６：００、１９：００、２２：００、１：００、４：００一天采样４次的时间序列可为５：００、１１：００、１７：００、２３：００。白天采样４次的时间序列可为春、秋季６：００、９：００、１２：００、１５：００?     

锌与龋病关系的研究进展

锌作为一种人体必需的金属微量元素,广泛分布于牙菌斑、唾液以及釉质表面,同时,也常被加入口腔清洁类产品中以达到控制菌斑,减少口气,防止牙石形成的目的。尽管有研究显示,锌可以有效地保护牙体硬组织,抑制口腔致龋菌的生长及产酸,在理论上有着良好的抗龋特性,但在实际的临床应用中,锌却没有展现出其在预防及治疗龋病方面的优势。可能是因为锌离子无法大量牢固地粘附于牙体表面,而已附着部分又常会因为各种环境因素的刺激而轻易脱落,从而无法有效发挥防龋效能。本文就锌与牙体硬组织间的相互作用、锌的抗微生物效应及其与龋病发生率的关联等作一综述。     

通过宏基因组学研究肠道微生物对结直肠癌患者影响的最新进展

人类肠道微生物已越来越受到医学界的广泛关注,人类肠道微生物不仅在人类健康方面,而且在人类疾病的发生和发展方面都有很大的作用。人们不断发现微生物与癌症之间的联系,特别是肠道微生物群和肠道肿瘤之间的联系。宏基因组学作为微生物研究的一种重要研究方法,在微生物与结直肠癌研究中发挥越来越重要的作用。近年来,通过宏基因组学研究肠道微生物菌群的变化为结直肠癌的发生和发展提供了新的见解,并且强调了癌症微生物群中宿主-微生物和微生物间相互作用的重要性。本综述回顾了通过宏基因组学研究肠道微生物与结直肠癌之间的关系,希望为癌症预防、诊断和治疗提供新的机会。     

Microbe-metabolite-host axis,two-way action in the pathogenesis and treatment of human autoimmunity

The role of microorganism in human diseases cannot be ignored. These microorganisms have evolved together with humans and worked together with body's mechanism to maintain immune and metabolic function. Emerging evidence shows that gut microbe and their metabolites open up new doors for the study of human response mechanism. The complexity and interdependence of these microbe-metabolite-host interactions are rapidly being elucidated. There are various changes of microbial levels in models or in patients of various autoimmune diseases (AIDs). In addition, the relevant metabolites involved in mechanism mainly include short-chain fatty acids (SCFAs), bile acids (BAs), and polysaccharide A (PSA). Meanwhile, the interaction between microbes and host genes is also a factor that must be considered. It has been demonstrated that human microbes are involved in the development of a variety of AIDs, including organ-specific AIDs and systemic AIDs. At the same time, microbes or related products can be used to remodel body's response to alleviate or cure diseases. This review summarizes the latest research of microbes and their related metabolites in AIDs. More importantly, it highlights novel and potential therapeutics, including fecal microbial transplantation, probiotics, prebiotics, and synbiotics. Nonetheless, exact mechanisms still remain elusive, and future research will focus on finding a specific strain that can act as a biomarker of an autoimmune disease.     

竹沥组分分析及抑菌作用

采用气相色谱 质谱联用方法分析了福建建瓯产竹沥成分,共分离鉴定有机物46种,其中主要成分18种,占出峰总面积的98%.研究了竹沥对不同类型腐败菌的抑制效果,结果显示,竹沥对细菌和真菌均具较强的抑制作用,其中金黄色葡萄球菌和枯草芽孢杆菌的抑菌圈直径为26mm,大肠杆菌为24mm,黑曲霉为23mm.表明竹沥是一种良好的天然抑菌剂.     

Molecular screening of unculturable bacteria present in men with reproductive failure

Objective  To determine the presence of unculturable bacteria using polymerase chain reaction (PCR) in infertile men with pyosperrmia. Design  Perspective clinical study. Setting  The study took place at the Department of Reproductive Medicine, Owaisi Hospital and Research Center; In vitro Fertilization Unit, Mahavir Hospital and Research Center; Center for Cellular and Molecular Biology; and Bharat Biotech Foundation, Hyderabad, India. Patients  A total of 68 infertile men and 15 donors, all with no symptoms of genito-urinary tract infections and sterile semen cultures were included in the study. Interventions  None. Main outcome measures  Screening bacteria using routine bacterial cultures and PCR based screening with universal eubarterial primers. Results  The statistical analysis of all the semen parameters in asthenazoospermic, azoospermic, ceyptazoospermic, severe oligospermic and mild oligospermic patients were found to be significant compared with the controls. All the groups were found to be significant compared with the controls (P < 0.05) except for volume and pus cells in the cryptozoospermia group. The Student’s t-test also was significant for the seminal parameters before and after treatment of 68 selected individuals with pyospermia and sterile cultures. A total of 44.11% (30/ 68) samples were collected from the negative culture of pyospermic infertile men have shown the presence of bacteria on amplification using PCR with universal eubacterial primers. The DNA was purified and sequenced. The sequences were checked for homology using DNASTAR and Ribosomal Data-Base Project II. A total of 90% of the samples have shown the nearest evolutionary relation to Pantoea P102 (AF394539) and 10% of samples have shown close relation with Burkholderia cepacia (AF042161). Conclusion  The routine bacteriological cultures were unable to detect certain bacterial species particularly with members of enterobacteriaceae family (Pantoea species). Polymerase chain reaction, when used for screening bacteria, can detect the unculturable form of bacteria in infertile men. No amplification for bacterial DNA was obtained in control samples (fertile men with sterile semen cultures.)     

Soil DNA libraries for anticancer drug discovery

Soil has the largest population of microbes of any habitat, but only about 0.3% of soil microbes are cultivable with current techniques. Cultured soil microbes have been an incredibly productive source of drugs, for example the cancer chemotherapeutics doxorubicin hydrochloride, bleomycin, daunorubicin and mitomycin. Unfortunately, the current yield of new drugs from soil microbes is low due to repeated cultivation of the same small fraction of cultivable microbes. Uncultured soil species represent a tremendous untapped resource of new antineoplastic agents. Methods have recently been developed to access the diversity of secondary metabolites from uncultured soil microbes. Briefly, total DNA is extracted from soil samples, purified, partially digested, and fragments inserted into vectors for expression in readily fermented microbes such as Escherichia coli. Clones expressing enzymatic and antibiotic activities that are encoded by novel sequences have been reported.     

Working Group report 4: exposure assessment for biological agents

This Working Group was assembled to review and evaluate methods currently used to estimate work site exposures to biological agents and to present recommendations on suitable measurement strategies. The current state of exposure assessment was evaluated for environments with organic dust including agriculture, composting, sewage and waste treatment processing, peat moss harvesting and handling, cotton and textile processing, greenhouse work, and grass seed processing. Methods for measurement of microbial contaminants in indoor environments were also considered. Important methods are emerging that use quantitative PCR for assessment of microbial agents. Difficulties exist with optimization of extraction to yield contaminant-free DNA without significant DNA loss. Advances in assays for microbial agents (e.g., endotoxin and glucans) as well as allergens have increased the utility of exposure assessment for these agents. A crucial area for further development is international harmonization of methodologies to reduce interlaboratory variability and to facilitate establishment of exposure guidelines. Endotoxin exposure assessment using the Limulus amebocyte lysate method is a high priority for harmonization because of its importance as a pulmonary inflammatory agent in many occupational settings.     

气溶胶喷雾对空气和物体表面的消毒效果

目的 测试气溶胶喷雾过氧乙酸、过氧化氢(H2O2)对医院病房、救护车内空气和表面消毒效果。方法 按“消毒技术规范”规定方法进行。结果 对白色葡萄球菌(即金黄色葡萄球菌)：过氧乙酸和H2O20.05％～0.15％20～30ml／m^3，作用5～30min，杀灭率为99.99％；对细菌芽胞：过氧乙酸0.1％～0.8％ 20～30ml／m^3，作用30～60min，杀灭率为99.99％；对自然菌：过氧乙酸0.6％20ml／m^3，作用60min，平均杀灭率为99．48％。结论 用气溶胶喷雾过氧乙酸对医院病房、救护车内空气和表面进行消毒处理：0.1％～0.8％，20～30ml／m^3，作用30～60min，均达到可靠的消毒效果；此方法使表面消毒和空气消毒相结合，较传统的甲醛熏蒸消毒效果好、毒性低、省药、省时、方便、易行。