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161.
Roest K Altinbas M Paulo PL Heilig HG Akkermans AD Smidt H de Vos WM Stams AJ 《Microbial ecology》2005,50(3):440-446
To gain insight into the microorganisms involved in direct and indirect methane formation from methanol in a laboratory-scale
thermophilic (55°C) methanogenic bioreactor, reactor sludge was disrupted and serial dilutions were incubated in specific
growth media containing methanol and possible intermediates of methanol degradation as substrates. With methanol, growth was
observed up to a dilution of 108. However, when Methanothermobacter thermoautotrophicus strain Z245 was added for H2 removal, growth was observed up to a 1010-fold dilution. With H2/CO2 and acetate, growth was observed up to dilutions of 109 and 104, respectively. Dominant microorganisms in the different dilutions were identified by 16S rRNA-gene diversity and sequence
analysis. Furthermore, dilution polymerase chain reaction (PCR) revealed a similar relative abundance of Archaea and Bacteria
in all investigated samples, except in enrichment with acetate, which contained 100 times less archaeal DNA than bacterial
DNA. The most abundant bacteria in the culture with methanol and strain Z245 were most closely related to Moorella glycerini. Thermodesulfovibrio relatives were found with high sequence similarity in the H2/CO2 enrichment, but also in the original laboratory-scale bioreactor sludge. Methanothermobacter thermoautotrophicus strains were the most abundant hydrogenotrophic archaea in the H2/CO2 enrichment. The dominant methanol-utilizing methanogen, which was present in the 108-dilution, was most closely related to Methanomethylovorans hollandica. Compared to direct methanogenesis, results of this study indicate that syntrophic, interspecies hydrogen transfer-dependent
methanol conversion is equally important in the thermophilic bioreactor, confirming previous findings with labeled substrates
and specific inhibitors. 相似文献
162.
Phylogenomic analysis of the receptor-like proteins of rice and Arabidopsis 总被引:6,自引:0,他引:6 下载免费PDF全文
The tomato (Lycopersicon esculentum) Cf-9 resistance gene encodes the first characterized member of the plant receptor-like protein (RLP) family. Other RLPs such as CLAVATA2 and TOO MANY MOUTHS are known to regulate development. The domain structure of RLPs consists of extracellular leucine-rich repeats, a transmembrane helix, and a short cytoplasmic region. Here, we identify 90 RLPs in rice (Oryza sativa) and compare them with functionally characterized RLPs from different plant species and with 56 Arabidopsis (Arabidopsis thaliana) RLPs, including the downy mildew resistance protein RPP27. Many RLPs cluster into four distinct superclades, three of which include RLPs known to be involved in plant defense. Sequence comparisons reveal diagnostic amino acid residues that may specify different molecular functions in different RLP subtypes. This analysis of rice RLPs thus identified at least 73 candidate resistance genes and four genes potentially involved in development. Due to the synteny between rice and other Gramineae, this analysis should provide valuable tools for experimental studies in rice and other cereals. 相似文献
163.
Bozkurt G Yuksel M Karabogaz G Sut N Savran FO Palanduz S Yigitbasi ON Algunes C 《Mutation research》2003,535(2):205-213
OBJECTIVE: The aim of this study was to assess whether occupational exposure to chronic, low doses of Iodine 131 (I-131) and Technetium 99m (Tc-99m) may lead to genotoxicity. Medical personnel occupied in nuclear medicine departments are occupationally exposed to low doses of I-131 and Tc-99m. The determination of the frequency of sister chromatid exchanges (SCEs) and of cells with a high frequency of SCEs (HFC) is considered to be a sensitive indicator for detecting genotoxic potential of mutagenic and carcinogenic agents. Therefore, we examined peripheral lymphocytes from nuclear medicine physicians for the presence of both SCE and HFC. METHODS: Sixteen exposed nuclear medicine physicians (non-smokers) were compared to 16 physicians (non-smokers) who had not been exposed to chemical or physical mutagens in their usual working environment at the same hospital. RESULTS: A statistically significant difference was found between SCE frequencies and HFC percentages measured in lymphocytes from the exposed and control groups. CONCLUSIONS: The present observation on the effect of chronic low doses of I-131 and Tc-99m indicates the possibility of genotoxic implications of this type of occupational exposure. Hence, the personnel who work in nuclear medicine departments should carefully apply the radiation protection procedures and should minimize, as low as possible, radiation exposure to avoid possible genotoxic effects. 相似文献
164.
塔克拉玛干沙尘暴源区空气细菌群落多样性 总被引:6,自引:1,他引:5
【目的】采集新疆塔克拉玛干沙漠腹地和周围沙尘暴源区空气样品,对不同样点沙尘暴发生前期、中期、后期空气细菌进行群落结构解析。阐明新疆沙尘暴源区空气细菌种属特征和群落多样性动态变化规律。【方法】基于Illumina HiSeq测序平台,利用双末端测序方法,构建16S rRNA小片段文库进行测序。【结果】塔克拉玛干沙尘暴源区空气细菌主要分为4门37个属,Proteobacteria占67.6%、Bacteroidetes占17.6%、Actinobacteria占11.7%、Firmicutes占2.9%;在属水平上,新疆沙尘暴源区有8个不同优势属,非度量多维尺度分析表明,不同样点在不同时期的细菌群落组成差异极显著;典范对应分析表明,环境因子对沙尘暴源区空气细菌多样性的影响大小为:海拔纬度经度湿度气压温度,且差异不显著。【结论】新疆沙尘暴源区空气细菌群落多样性和丰富度高;不同样点沙尘暴前期、中期、后期的空气细菌群落组成差异极显著;沙尘暴对5个源区固有细菌群落影响差异极显著。 相似文献
165.
Summary False positive transformants obtained during plant transformation experiments on species of the monocotyledonous genus Dioscorea (yam) are described. The false positive results were found to be due to endophytic bacteria which exist within aseptically micropropagated shoot cultures and which express -glucuronidase (GUS). The bacteria were isolated and identified as two species of Curtobacterium. The expression of GUS in these organisms was found to be induced by a variety of glucuronide substrates. The induction of GUS activity in the bacteria can be inhibited by chloramphenicol, tetracycline, ticarcillin and sodium azide. Implications of these results for use of the gus gene in plant transformation work are discussed.Abbreviations DTT
Dithiothreitol
- EDTA
Ethylenediamine tetra-acetic acid
- ELISA
Enzyme-linked immuno-sorbent assay
- GUS
-glucuronidase
- LB
Luria Bertani
- MUG
4-Methylumbelliferyl--D-glucuronide
- PNPG
p-nitrophenyl--D-glucuronide
- PVP
Polyvinylpyrrolidone
- SDS
Sodium dodecyl sulphate
- TAE
Tris-acetate-EDTA buffer
- X-Gluc
5-Bromo-4-chloro-3-indolyl--D-glucuronide 相似文献
166.
Yahya Nural Muge Gemili Mahmut Ulger Hayati Sari Laurens M. De Coen Ertan Sahin 《Bioorganic & medicinal chemistry letters》2018,28(5):942-946
In this study, a series of polysubstituted methyl 5,5-diphenyl-1-(thiazol-2-yl)pyrrolidine-2-carboxylate derivatives were designed and synthesized by the cyclization reaction of methyl 1-(benzoylcarbamothioyl)-5,5-diphenylpyrrolidine-2-carboxylates and 2-bromo-1-(4-substituted phenyl)ethanones in 70–96% yield. The starting pyrrolidine derivatives were synthesized via a 1,3-dipolar cycloaddition reaction in 83–88% yield. The stereochemistry of one of these methyl 5,5-diphenyl-1-(thiazol-2-yl)pyrrolidine-2-carboxylate derivatives was characterized by a single crystal X-ray diffraction study and the acid dissociation constants of these compounds were determined. An antimicrobial screening was performed against different bacterial and fungal strains and against the M. tuberculosis H37Rv strain. Interesting antibacterial activity was observed for two compounds against the A. baumannii strain with MIC values of 31.25?µg/mL (Ampicillin: 125?µg/mL) and against the M. tuberculosis H37Rv strain with MIC values of 0.98–1.96?µg/mL (Isoniazid: 0.98?µg/mL, Ethambutol: 1.96?µg/mL). Therefore, these structures can be considered as good starting points for the development of new powerful antimycobacterial agents. 相似文献
167.
Murat Kaya Vykintas Baublys Idris Sargin Ingrida Šatkauskienė Algimantas Paulauskas Bahar Akyuz Esra Bulut Vaida Tubelytė Talat Baran Osman Seyyar Mahmut Kabalak Huseyin Yurtmen 《Food biophysics》2016,11(1):10-19
Chitin specimens from 16 arthropod species (13 of Insecta and 3 of Arachnida) were isolated for the first time using the same method. Fourier Transform Infrared Spectrometry (FTIR), Thermogravimetric Analysis (TGA), X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and elemental analysis have been applied to determine how physicochemical properties of chitin specimens are affected by taxonomic relationship. The characterisation studies revealed that physicochemical nature of the chitin specimens differed greatly and were found partially specific to taxa. Significant differences in the surface morphologies of chitin specimens were observed even in the same order. However, the chitin contents were recorded to be specific to the order in the class Insecta. The highest chitin content was observed in Coleoptera (18.2–25.2 %) followed by Hemiptera (10.6–14.5 %), Odonata (9.5–10.1 %), Hymenoptera (7.8–9.3 %), Diptera (8.1 %), Blattodea (4.7 %). In addition, the crystalline index (CrI) values of chitin specimens from Coleoptera were found to be higher than the other orders in Insecta. This study revealed that the chitin contents and CrI values can be related to taxonomical relationships. 相似文献
168.
169.
Ergin K Aktuğ H Başloğlu H Başaloğlu HK Yilmaz MI Turgut M 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》2007,29(5):291-295
OBJECTIVE: To determine the cross-section area of adrenal medulla and the percentage of Ki-67 (a proliferation marker) of the adrenal gland in diabetic rats after leptin injection. STUDY DESIGN: Twenty-nine male Wistar rats were randomly divided into 3 groups: control (C) group (n = 9), diabetes mellitus (DM) group (n = 10) and leptin-injected diabetes mellitus (DM+L) group (n = 10). Experimental DM was induced by a single intraperitoneal dose of streptozotocin (40 mg/kg). After this, leptin (100 microg/kg) was injected subcutaneously for a period of 2 weeks in the diabetic group. RESULTS: An atrophy of adrenal medulla in the DM group was observed, and this atrophy returned to normal morphology after injection of leptin. In addition, an increase in the Ki-67 percentage was demonstrated in the zona reticularis layers in the DM+L group. CONCLUSION: Our study indicated that leptin stimulates the sympathoadrenal system and the androgen producing adrenal cortex in DM rats. 相似文献
170.
保护新疆马鹿塔里木亚种的建议 总被引:1,自引:0,他引:1
马鹿塔里木亚种分布于新疆塔里木盆地各沿河地带,强度适应荒漠生境。采用分子系统学方法研究表明,世界马鹿分为东西两大系统,马鹿塔里木亚种是我国唯一属于西部系统的亚种。在中国濒危动物红皮书中被列为濒危(E)亚种,按国际自然与自然资源保护联盟(IUCN)1993年制定的世界物种红色名录濒危定级标准,属于极危级(EN)。自20世纪50年代以来,由于自然和人为因素的影响,种群数量急骤下降,现今马鹿塔里木亚种在塔河流域被隔离为莎雅、尉犁和且末3个小种群,当前该亚种正受到栖息地减小和片断化的双重影响,而且因遗传漂变和近亲繁殖的不断增加也进一步加剧它的濒危程度。为有效保护该物种特提出可行的保护建议。 相似文献