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1.
Yoshinobu Naoshima Eiji Nakagawa Shoji Wakabayashi Shûichi Hayashi 《Bioscience, biotechnology, and biochemistry》2013,77(6):1419-1420
A methanol-utilizing bacterium, which produced red to pink pigments and assimilated methanol via icl- serine pathway, was isolated from soil and tentatively designated as Pseudomonas MS 31. This bacterium produced L-serine when glycine was added to the growth medium at the late exponential phase of growth. The cells showed high L-serine degradation activity. Chelating agents and some metal ions, which inhibited L-serine degradation, stimulated the L-serine accumulation. In the presence of 0.1 ? 1 mM EDTA, o-phenanthroline, 8-hydroxyquinoline, α,α'-dipyridyl, cobalt sulfate or nickel sulfate, this bacterium produced 0.7?2.1mg L-serine from 4mg glycine per ml culture. 相似文献
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《Biodemography and social biology》2013,59(3-4):331-336
Abstract In the present paper 702 families have been studied belonging to different endogamous groups in three multicaste villages of Srikakulam District, Andhra Pradesh. It is observed that 33.76 per cent of families are consanguineous marriages. With regard to the types of marriages, 12.11 per cent are uncle‐niece; 14.10 per cent are matrilateral cross‐cousins; 5.84 per cent are patrilateral cross‐cousins; 0.57 per cent are first cousins once removed, and 1.14 per cent are second cousins. There are only six couples (0.86 per cent) in intercaste marriages. The coefficient of inbreeding for autosomal and sex‐linked genes, 0.045 and 0.059, respectively, for Chakalis which are higher than Kalingas (F = 0.03; F1 = 0.038), Segidis (F = 0.031; F1 = 0.041), Velamas (F = 0.026; F1 = 0.036), Vysyas (F = 0.027; F1 = 0.034), Malas (F = 0.017; F1 = 0.026), and others (F = 0.026; F1 = 0.032). The t‐tests for mean marriage distances are statistically significant among all castes, but chi‐squares for intergroup difference of consanguineous and nonconsanguineous marriages are statistically significant only among Kalingas and Chakalis, Vysyas and Chakalis, and Malas and Chakalis. 相似文献
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S. Mohan Jain 《Journal of biosciences》1997,22(5):585-592
Begonia
x
elatior
plantlets which regenerated from leaf disk callus showed variations in plant morphology, number of flowers per plant, and
flower size. Variations in flowering period, number of flowers per plant, and flower morphology were observed in
Saintpaulia ionantha
L. plants directly regenerated from leaf disk explants. The cytokinins, benzylaminopurine and zeatin, tested in the culture
medium did not affect the basic plant characteristics including flower colour which remained stable in both species. Micropropagation
of selected somaclones having the desirable trait of high number of flowers per plant was stable in the MV2 and MV3 generations. 相似文献
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Abstract Cohorts of willow sawfly (Nematus oligospilus) were reared in the laboratory on crack willow (Salix fragilis) at seven constant temperatures between 11.3 and 28.8°C. Larvae developed through 5–7 instars. Body size (length) of adult females was influenced by temperature and was strongly correlated with fecundity (R2 = 0.8973). The developmental threshold (to), determined through linear regression, was calculated to be 8.1°C, and the thermal accumulation above to required to complete one generation was 321 degree‐days. The number of degree‐days available for seasonal development of the sawfly at 10 sites throughout New Zealand was calculated. Allowing for the period of diapause, it was estimated that N. oligospilus might potentially develop through up to seven generations per year in the North Island and three generations per year in the south of the South Island. 相似文献
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Interspecific and intergeneric hybridizations were carried out to evaluate the genomic relationships among species of Hystrix Moench and to study the relationships between Hystrix species and Psathyrostachys huashanica Keng (2n=2x=14, Nsh). Meiotic pairing in hybrids of Hystrix duthiei ssp. duthiei × P. huashanica (2n=3x=21), Hystrix duthiei ssp. longearistata × P. huashanica (2n=3x=21) and H. patula × P. huashanica (2n=3x=21) averaged 5.18, 5.11 and 0.29 bivalents per cell, while H. patula × H. duthiei ssp. longearistata (2n=4x=28) averaged 25.36 univalents and 1.32 bivalents per cell, respectively. The results indicate that (i) H. duthiei ssp. duthiei and H. duthiei ssp. longearistata have one set of Ns genome from Psathyrostachys; (ii) H. patula has no Ns genome; (iii) genomes of H. duthiei ssp. duthiei and H. duthiei ssp. longearistata are non-homologous to those of H. patula. The genomic relationships between H. patula and other Hystrix species are also discussed. 相似文献
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[背景] 水产病原细菌严重威胁水产动物健康且制约水产养殖业发展,细菌性鱼病的有效防治成为水产养殖领域亟待解决的问题。[目的] 筛选对水产病原细菌有抑制效果的菌株,并研究其抑菌特性及其在水产细菌病害防治中的实际效果。[方法] 通过16S rRNA基因测序、构建系统发育树和生理生化鉴定确定筛选菌株的进化地位,通过乙酸乙酯萃取获得抑菌物质粗提物,通过偶氮酪蛋白法检测菌株胞外蛋白酶活力,采用结晶紫染色法对菌株的生物膜形成能力进行测定,通过浸浴攻毒模型确定所筛菌株对维氏气单胞菌的防治作用。[结果] 从泡菜发酵物中筛选出一株乳酸菌DH,经16S rRNA基因测序、发育树分析和生理生化鉴定确定其为肠膜明串珠菌,该菌分泌的胞外抑菌物质对鼠伤寒沙门氏菌、大肠埃希氏菌、铜绿假单胞菌、杀鲑气单胞菌、希瓦氏菌和维氏气单胞菌表现出抑菌效果,其抑菌物质能被乙酸乙酯萃取并且具有热稳定性。菌株DH能够显著抑制待测菌株的蛋白酶产量和生物膜形成能力,并且对维氏气单胞菌浸浴攻毒有防治作用。[结论] 肠膜明串珠菌DH通过分泌抑菌物质抑制水产病原细菌的生长,能够为细菌性鱼病的防治提供一定的理论和应用潜力。 相似文献
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Timothy G.F. Kittel Mark W. Williams Kurt Chowanski Michael Hartman Todd Ackerman Mark Losleben 《Plant Ecology & Diversity》2015,8(5-6):607-624
Background: Long-term climate trends in mountain systems often vary strongly with elevation.Aims: To evaluate elevation dependence in long-term precipitation trends in subalpine forest and alpine tundra zones of a mid-continental, mid-latitude North American mountain system and to relate such dependence to atmospheric circulation patterns.Methods: We contrasted 59-year (1952–2010) precipitation records of two high-elevation climate stations on Niwot Ridge, Colorado Front Range, Rocky Mountains, USA. The sites, one in forest (3022 m a.s.l.) and the other in alpine tundra (3739 m), are closely located (within 7 km horizontally, ca. 700 m vertically), but differ with respect to proximity to the mountain-system crest (the Continental Divide).Results: The sites exhibited significant differences in annual and seasonal precipitation trends, which depended strongly on their elevation and distance from the Continental Divide. Annual precipitation increased by 60 mm (+6%) per decade at the alpine site, with no significant change at the subalpine site. Seasonally, trends at the alpine site were dominated by increases in winter, which we suggest resulted from an increase in orographically generated precipitation over the Divide, driven by upper-air (700 hPa) north-westerly flow. Such a change was not evident at the subalpine site, which is less affected by orographic precipitation on north-westerly flow.Conclusions: Elevation dependence in precipitation trends appears to have arisen from a change in upper-air flow from predominantly south-westerly to north-westerly. Dependence of precipitation trends on topographic position and season has complex implications for the ecology and hydrology of Niwot Ridge and adjacent watersheds, involving interactions among physical processes (e.g. snowpack dynamics) and biotic responses (e.g. in phenologies and ecosystem productivity). 相似文献
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【背景】由禾谷镰刀菌(Fusarium graminearum)引起的小麦赤霉病严重威胁我国的小麦生产。【目的】筛选对禾谷镰刀菌具有拮抗能力的链霉菌菌株,为生防菌剂开发提供理论基础。【方法】利用平板对峙法筛选对禾谷镰刀菌具有拮抗能力的链霉菌;通过形态特征、生理生化特征和16S rRNA基因序列分析对其进行鉴定;通过病原菌菌丝生长、孢子产生及萌发抑制试验分析其发酵液的抑菌活性;利用人工接种试验测定该菌株发酵液的防病效果。【结果】筛选到一株对禾谷镰刀菌具有较强拮抗活性的链霉菌21-1,抑菌率为59.5%。依据形态特征、生理生化特性和16S rRNA基因序列分析,将该菌株鉴定为黄三素链霉菌(Streptomycesflavotricini)。菌株21-1发酵液能够抑制禾谷镰刀菌的菌丝生长、孢子产生及萌发过程,而且可以降低禾谷镰刀菌菌丝中可溶性蛋白质的含量,并增加丙二醛的含量。菌株21-1可以产生蛋白酶及纤维素酶。菌株21-1菌液10倍稀释液对小麦赤霉病的防效最佳,为70.1%。此外,菌株21-1发酵液对其他8种植物病原菌均有较好的抑制作用。【结论】菌株21-1对禾谷镰刀菌有较好的抑菌活性,具... 相似文献
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Salama G Choi BR Azour G Lavasani M Tumbev V Salzberg BM Patrick MJ Ernst LA Waggoner AS 《The Journal of membrane biology》2005,208(2):125-140
Membrane potential measurements using voltage-sensitive dyes (VSDs) have made important contributions to our understanding
of electrophysiological properties of multi-cellular systems. Here, we report the development of long wavelength VSDs designed
to record cardiac action potentials (APs) from deeper layers in the heart. The emission spectrum of styryl VSDs was red-shifted
by incorporating a thienyl group in the polymethine bridge to lengthen and retain the rigidity of the chromophore. Seven dyes,
Pittsburgh I to IV and VI to VIII (PGH I-VIII) were synthesized and characterized with respect to their spectral properties in organic solvents and heart muscles. PGH VSDs
exhibited 2 absorption, 2 excitation and 2 voltage-sensitive emission peaks, with large Stokes shifts (> 100 nm). Hearts (rabbit,
guinea pig and Rana pipiens) and neurohypophyses (CD-1 mice) were effectively stained by injecting a bolus (10–50 μl) of stock solution of VSD (2–5 mM) dissolved in in dimethylsulfoxide plus low molecular weight Pluronic (16% of L64). Other preparations were better stained
with a bolus of VSD (2–5 mM) Tyrode’s solution at pH 6.0. Action spectra measured with a fast CCD camera showed that PGH I exhibited an increase in fractional
fluorescence, ΔF/F = 17.5 % per AP at 720 nm with 550 nm excitation and ΔF/F = − 6% per AP at 830 nm with 670 nm excitation. In frog hearts, PGH1 was stable with ∼30% decrease in fluorescence and AP
amplitude during 3 h of intermittent excitation or 1 h of continuous high intensity excitation (300 W Xe-Hg Arc lamp), which
was attributed to a combination of dye wash out > photobleaching > dynamic damage > run down of the preparation. The long
wavelengths, large Stokes shifts, high ΔF/F and low baseline fluorescence make PGH dyes a valuable tool in optical mapping and for simultaneous mapping of APs and intracellular
Ca2+. 相似文献
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ABSTRACT The systematic classification of tree frogs (Hyla) inhabiting different regions of the country of Turkey is unclear. Recordings of natural advertisement calls of individual male tree frogs in different locations in Turkey were analyzed to determine variation in acoustic features that may be related to taxonomic status. Multivariate analysis of covariance showed that call duration, intercali interval and number of pulses per call varied significantly between frogs in different locales. Call duration, intercall interval, and number of pulses per call were related to air temperature. Dominant frequency differed significantly between different groups of frogs, and was temperature-independent. These data are consistent with the hypothesis that tree frogs in Turkey represent two distinct species, Hyla arborea and Hyla savignyi. 相似文献
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【背景】细菌群落在土壤养分循环中扮演着重要角色,并且土壤理化性质及作物产量会对其产生一定的影响。【目的】明确河套灌区滴灌条件下聚丙烯酰胺和生物炭共施对土壤细菌群落多样性及结构组成、理化因子和玉米产量的影响。【方法】设置对照(CK)、聚丙烯酰胺22.5 kg/hm2+生物炭9000kg/hm2(PB1)、聚丙烯酰胺22.5kg/hm2+生物炭13500kg/hm2(PB2)和聚丙烯酰胺22.5 kg/hm2+生物炭18 000 kg/hm2(PB3)这4个不同处理,利用高通量测序技术研究土壤细菌群落与环境因子和玉米产量的相互关系。【结果】与CK相比,PB1和PB2处理均提高了土壤细菌群落的α多样性指数(Chao1指数和Shannon指数)。聚丙烯酰胺和生物炭共施可改变土壤细菌群落结构组成,不同处理的土壤细菌优势类群为变形菌门(Proteobacteria)和Subgroup_6。PB1处理的土壤水解氮和PB2处理的有效钾含量增加较为明显,且PB2处理的综合土... 相似文献
14.
Vikki Ho Sarah Peacock Thomas E. Massey Roger W. Godschalk Frederik J. van Schooten Janet E. Ashbury 《Biomarkers》2013,18(8):735-741
AbstractPurpose: Examine the association between bulky DNA adduct levels in colon mucosa and colorectal adenoma prevalence, and explore the correlation between adduct levels in leukocytes and colon tissue.Methods: Bulky DNA adduct levels were measured using 32P-postlabelling in biopsies of normal-appearing colon tissue and blood donated by 202 patients. Multivariable logistic regression was used to examine associations between DNA adducts, and interactions of DNA adduct-DNA repair polymorphisms, with the prevalence of colorectal adenomas. Correlation between blood and tissue levels of DNA adducts was evaluated using Spearman’s correlation coefficient.Results: An interaction between bulky DNA adduct levels and XPA rs1800975 on prevalence of colorectal adenoma was observed. Among individuals with lower DNA repair activity, increased DNA adduct levels were associated with increased colorectal adenoma prevalence (OR?=?1.41 per SD increase, 95%CI: 0.92–2.18). Conversely, among individuals with normal DNA activity, an inverse association was observed (OR?=?0.60 per SD increase, 95%CI: 0.34–1.07). Blood and colon DNA adduct levels were inversely correlated (ρ?=??0.20).Conclusions: Among genetically susceptible individuals, higher bulky DNA adducts in the colon was associated with the prevalence of colorectal adenomas. The inverse correlation between blood and colon tissue measures demonstrates the importance of quantifying biomarkers in target tissues. 相似文献
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A. A. Ivanov V. I. Salyanov S. A. Strel’tsov N. A. Cherepanova E. S. Gromova A. L. Zhuze 《Russian Journal of Bioorganic Chemistry》2011,37(4):472-482
Five fluorescent symmetrical dimeric bisbenzimidazoles DB(n) containing four 2,6-substituted benzimidazole cores and differing in the length of the oligomethylene linker between two
bisbenzimidazole rings (n = 3, 4, 5, 7, 11) have been synthesized. The ability of the dimeric bisbenzimidazoles to form complexes with the double-stranded
DNA has been shown by spectral methods. Upon binding to the double-stranded DNA, DB(n) are localized in the narrow groove. The data on the inhibition of the DNA methyltransferase Dnmt3a by DB(n) indicate that dimeric bisbenzimidazoles DB(3) and DB(11) site-specifically bind to the oligonucleotide duplex. 相似文献
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Lilliam Casillas-Martinez Millie L. Gonzalez Zamara Fuentes-Figueroa Cyd M. Castro Deborah Nieves-Mendez Carmen Hernandez 《Geomicrobiology journal》2013,30(6):269-281
Seasonal variations in precipitation changed the community composition and microbial activity in a hypersaline, tropical microbial mat, in Cabo Rojo, PR. Using a combination of dissection, light, and transmission electron microscopy, terminal restriction fragment length polymorphism (T-RFLP), in situ microelectrode studies, and 35 S isotope incubations, we documented the major differences between wet and dry seasons. During the wet season (precipitation 177 mm), cyanobacterial (green layer) and anoxyphototrophic (pink layer) communities, as well as the black FeS layer were well-developed, and T-RFLP patterns indicated a diverse community. The rate of oxygenic photosynthesis was 49 μ M min ? 1 . Aerobic respiration was 29 μ M min ? 1 , and sulfate reduction was 264 nmol cm ? 3 h ? 1 . During the dry season (precipitation 51 mm), cyanobacteria and anoxyphototrophs were less diverse and abundant, and T-RFLP patterns were less complex. The O 2 production rate was reduced to 9 μ M min ? 1 , as was O 2 consumption (7 μ M min ? 1 ) and sulfate reduction (26 nmol cm ? 3 h ? 1 ). Aragonite, calcite, halite, and quartz were the predominant minerals. Seasonal differences were found in the green and pink layers for both halite and quartz. Gypsum was not observed, likely due to a sample handling artifact. The fluctuations in community composition and metabolic activity, principally reflected in fluctuations in binding and trapping potential of the uppermost mat community, might be responsible for the observed differences in mineralogy. 相似文献
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??????? 目的
探索在医疗信息化背景下,医生诊疗患者过程中的信息需求特点,以帮助找到对策,提高医疗质量。方法 采用问卷调查结合半结构化访谈调查北京大学两家附属医院272名住院医生。结果 医生工作强度高,信息需求大,综合医院门诊医生平均每半天看30位患者;在诊疗过程中,综合医院医生56.1%每天出现≥6次信息需求。这些信息需求最多出现在制定医疗方案阶段;对于两医院的医生,网络信息资源也是一个重要信息获取途径;医生希望信息资源具有信息权威准确、及时更新,载体方便携带、随时可查询及结合临床实际、诊疗方案实现常规化等特点。结论 医生在给患者看病过程中普遍存在信息需求。移动医疗、临床路径结合循证医学有很强的应用前景。 相似文献
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Capsule Parasitism has no apparent detrimental effect. Aims To determine whether parasitism by a haematophagous nest ectoparasite, the Louse Fly Crataerina pallida has a detrimental effect on the reproductive success of its Common Swift Apus apus hosts. Methods An association between C. pallida abundance and various host life‐history parameters indicative of host reproductive success were sought. Results No relationship was found between measures of parasite load and clutch size, brood size, length of time required to reach nestling asymptotic weight, the length of time from hatching to fledging, fledging success per nest, fledgling weight, and fledgling size. Conclusion Parasitism has no apparent detrimental effect upon its hosts. Louse Flies may have evolved low levels of virulence or the negative effects expected as a consequence of its parasitism may be expressed on life‐history traits other than those studied here. 相似文献
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Summary We analyse the fruiting phase of the life cycleof Digitalis thapsi L. We studied the production and size of seeds and capsules, and the interpopulational variability and inter-relationships of these parameters. The capsule volume, number of seeds per capsule, of seeds per individual, and of capsules per individual were inter-related and fairly affected by the medium, whereas seed weight was found to bea more independent character. A germination study showed that the species has agreat germinative capacity and has positive photoblasty. It is non-dormant especially if incubated under experimental conditions close to the climatic conditions of the site of provenance of the samples. An increase in temperature speeds up the process without increasing germinability. The morphological and biometric characteristics of the first stages of development of the species following germination were analysed. It was found that seed weight is not positively correlated with cotyledon length nor with any of the other parameters con-sidered, and that the length of the fifth leaf is a useful parameter to express inter-populational genetic variability. Seedling production in spring seems to be influenced more by physical than by chemical factors. 相似文献