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1.
球壳孢目真菌个体发育研究I:壳二胞等四属   总被引:2,自引:0,他引:2  
周永力  吕国忠 《菌物系统》1998,17(3):199-205
人工培养条件下,用光学显微镜和透射电子显微镜以球壳孢目(Sphaerosidales)的AscochytaPhyllostictaPhomopsis,Septoria四属进行个体发育研究,明确了其产孢方式:Ascochyta和Plyhhosticta为内壁芽生瓶梗式:Phompsis为全壁芽生壁梗式,Septoria为全璧芽生合轴式,这一结果为属级分类提供了可靠的依据,产孢方式是属内共同具有的稳定  相似文献   

2.
热带次生林利用方式与土壤微生物活性   总被引:1,自引:0,他引:1  
热带次生林利用方式与土壤微生物活性许炼烽,朱伍坤(国家环保局华南环境科学研究所,广州510655)WaysofUtilizingTropicalSecondaryForestandSoilMicrobialActivity.¥XuLianfeng;Z...  相似文献   

3.
12株酵母菌的亲缘关系分析   总被引:1,自引:0,他引:1  
克隆了9株假线酵母和1株克鲁维酵母的25SrDNA片段,测定其5′端部分苷酸序列与报道的Candidaalbicans及Saccharomycescerevisiae25SrDNA相应区域的核苷酸序列比较,采用neighbor-joining和boot-strap法分析并绘制系统树,结果提示CandidakefyrCBS834与Kluyveromyces cicerisporusCBS4857亲缘  相似文献   

4.
春玉米与生姜间作不同种植方式农田生态效应研究   总被引:4,自引:0,他引:4  
春玉米与生姜间作不同种植方式农田生态效应研究姚向高王爱玲(河南农业大学农学院,郑州450002)StudyoftheEcologicalEfcctsofDiferentTreatmentofIntercroppingofSpringMaizeand...  相似文献   

5.
金由辛 《生命的化学》2000,20(4):145-146
Sasaki等在ProcNatlAcadSciUSA 2 0 0 0年第 4期上报道了一种不依赖甲硫氨酸的翻译起始方式[1] 。PSIV (Plautiastaliintestinevirus)是一种昆虫RNA病毒 ,属蟋蟀麻痹样病毒组 (Cricketparalysis likeviruses) ,为正链RNA病毒。属于该组的还有DCV、RhPV、HiPV等。该组病毒的理化性质与哺乳动物的小RNA病毒 (picornavirus)相似 ,但基因图 1  (A)PSIV基因组结构 ;(B)预测的外壳蛋白编码区上游的茎环结构组织不同。…  相似文献   

6.
福建漳平早二叠世Schwagerinacushmani动物群的层位介于梁山组与含假希瓦格亚科分子的马平组之间。动物群分子以Schwagerinacushmani,Darvasitessinensis,Pseudofusulinagalowayi为主,与湘东南的Schwagerinacushmani类群、江苏宁镇山区的Darvasitesordinatus类群相一致。  相似文献   

7.
云南珍珠茅属一新种   总被引:1,自引:0,他引:1  
钱义咏 《植物研究》1999,19(3):241-243
江城珍珠茅 新种 图1ScleriajiangchengensisY.Y.Qian,sp.nov.(Subgen,Scleria,Sect.Elatae)SpeciesaffinisS.herbecarpaeNees,sedfoliissubtusvillosis,spiculis3.5~4.5mmlongis,nucibus2.5~2.8mmdiam,reticulatisdiffert.Rhizomaligneumrepens,citra15cmlongum,squamisbrunneis,…  相似文献   

8.
斜纹夜蛾核多角体病毒基因组全序列分析   总被引:1,自引:0,他引:1  
已完成斜纹夜蛾核多角体病毒 (Spodopteralituramulticapsidnucleopolyhedrovirus,SpltMNPV)基因组全序列测定。SpltMNPV基因组全长 1 39341bp ,碱基组成中G C含量为 42 .7% ,与已发表的Spodopteraexiguamulticapsidnucleopolyhedrovirus (SeMNPV) (44 % )和Bombyxmorinucleopolyhedrovirus (BmNPV) (40 % )相似 ,而与Lymantriadisparmulti capsi…  相似文献   

9.
November 3- 5 ,2 0 0 2 ,ShanghaiThebiosynthesisofaurodrosopterininDrosophilamelanogaster :Purification ,cloningandcharacterizationofdi hydropterindeaminaseChiyoungAhn ,JaekwangKim ,SangickPark ,JeongbinYim (SchoolofBiologicalSciences,SeoulNationalUniversity ,Seoul 15 …  相似文献   

10.
东濮凹陷早第三纪的海侵(泛)事件   总被引:11,自引:0,他引:11  
依据生物化石Sphenolithus ciperoensis,Dictyococcites abisectus,Coccolithus pelagicus,Reticulofenestra sp.,Sinocysta minuta,S.subtilis,Cordosphaeridium,Achomosphaera,Spiniferites,Ophinomorpha nodosa,Cladosiph  相似文献   

11.
MOTIVATION: Each protein performs its functions within some specific locations in a cell. This subcellular location is important for understanding protein function and for facilitating its purification. There are now many computational techniques for predicting location based on sequence analysis and database information from homologs. A few recent techniques use text from biological abstracts: our goal is to improve the prediction accuracy of such text-based techniques. We identify three techniques for improving text-based prediction: a rule for ambiguous abstract removal, a mechanism for using synonyms from the Gene Ontology (GO) and a mechanism for using the GO hierarchy to generalize terms. We show that these three techniques can significantly improve the accuracy of protein subcellular location predictors that use text extracted from PubMed abstracts whose references are recorded in Swiss-Prot.  相似文献   

12.
Many different techniques have been used for xylem sap collection, but few direct comparisons of techniques have been conducted and few comparisons have been based on comprehensive analyses of xylem sap. Moreover, the suitability of extraction techniques for use on plants grown under water-stress conditions has not been addressed. Xylem sap was extracted from both well-watered and water-stressed Zea mays plants using three different techniques. The main aim was to determine how the extraction method altered the correlations between sap constituents and stomatal conductance in order to determine which relationships change with extraction technique. A 'root pressure' technique was the simplest method of extracting large volumes of sap, but the low sap delivery rates altered the composition of sap. Two pressurization techniques that varied in the position from which sap was collected were tested. The pressurization techniques allowed for the control of delivery rates that influence sap constituent concentrations. The position from which xylem sap was collected on the plant was also found to be important. All three techniques produced consistent correlations between ABA and chloride delivery rates and changes in stomatal conductance, suggesting that each technique could be applied to identify certain putative xylem-borne signals.  相似文献   

13.
DNA fingerprinting techniques for microorganisms   总被引:13,自引:0,他引:13  
A whole array of DNA-fingerprinting techniques, which provide indirect access to DNA sequence polymorphism in order to assess species or clonal identity of bacterial organisms or in order to study bacterial genome composition, have been described during past decades. Nomenclature has been sometimes erroneous and/or confusing, also because of hybrid techniques that combine different approaches. It can be shown that most techniques study the sequence polymorphism of only the chromosome, or only the plasmid(s) or only a gene or gene fragment and that the sequence polymorphism is revealed by AFLP (amplified fragment length polymorphism) or by RFLP (restriction fragment length polymorphism) or by special electrophoresis techniques. Starting from these considerations, some taxonomy of techniques, which enables more appropriate nomenclature, can be developed.  相似文献   

14.
I have tried to show (a) that results in the literature suggest that blue tits and coal tits survive better in their usual habitats of broad-leaved and conifer woods respectively; (b) that the higher mortality in the ‘wrong’ habitat may be attributed at least in part to an inability to acquire an adequate supply of food; (c) from my own and other people's field observations, that wild coal tits and blue tits use different feeding techniques; (d) from my own laboratory experiments, that each species is ‘best’ at the feeding techniques which it in general uses in the wild, and also that each species prefers to use the feeding techniques at which it is ‘best’; (e) that the feeding techniques of coal tits may be adapted to exploit the type of food supply found in conifers, while those of blue tits may be adapted for feeding in broad-leaved trees.  相似文献   

15.
Central tendency, linear regression, locally weighted regression, and quantile techniques were investigated for normalization of peptide abundance measurements obtained from high-throughput liquid chromatography-Fourier transform ion cyclotron resonance mass spectrometry (LC-FTICR MS). Arbitrary abundances of peptides were obtained from three sample sets, including a standard protein sample, two Deinococcus radiodurans samples taken from different growth phases, and two mouse striatum samples from control and methamphetamine-stressed mice (strain C57BL/6). The selected normalization techniques were evaluated in both the absence and presence of biological variability by estimating extraneous variability prior to and following normalization. Prior to normalization, replicate runs from each sample set were observed to be statistically different, while following normalization replicate runs were no longer statistically different. Although all techniques reduced systematic bias to some degree, assigned ranks among the techniques revealed that for most LC-FTICR-MS analyses linear regression normalization ranked either first or second. However, the lack of a definitive trend among the techniques suggested the need for additional investigation into adapting normalization approaches for label-free proteomics. Nevertheless, this study serves as an important step for evaluating approaches that address systematic biases related to relative quantification and label-free proteomics.  相似文献   

16.
This review article evaluates various techniques that have been used to determine in vivo loads in the human knee. Two main techniques that have been used are telemetry, which is an experimental approach, and mathematical modeling, which is a theoretical approach. Telemetric analyses have previously been used to determine the in vivo loading of the human hip and more recently evaluated in the determination of in vivo knee loads. Mathematical modeling approaches can be categorized two ways; those that use optimization techniques to solve an indeterminate system and those that utilize a reduction method that minimizes the number of unknowns, keeping the system solvable as the number of equations of motion are equal to the number of unknown quantities. More recently, we have developed an approach that relies fully on the use of in vivo data from fluoroscopy, CT scanning, magnetic resonant imaging and a revised motion analysis technique that involves only two markers on each rigid body. A review of all techniques revealed a wide range of forces at the human knee, ranging from 1.9 to 7.2 times body weight during level walking.  相似文献   

17.
Opportunities for synthetic plant chimeral breeding: Past and future   总被引:6,自引:0,他引:6  
Many plant periclinal chimeras are selected by horticulturalists due to their distinctive, valuable phenotypes, and because they are relatively stable. Most of these have arisen by induced or spontaneous mutation. Interspecific chimeras have been accidentally produced from graft unions of plants from a wide range of families. Early last century Winkler developed a technique to produce interspecific chimeras from graft unions (graft chimeras). More recently in vitro techniques have been developed to synthesize interspecific and intervarietal chimeras. However, these techniques have only been successful for species in the families Solanaceae and Cruciferae, and rarely assessed on plants in other families. Research is required to improve these techniques or develop new approaches so that the efficiency of chimeral shoot production is improved and the techniques are applicable to plants in a wide range of families. The unique characteristics of interspecific or intervarietal chimeras show the potential of chimeral breeding to produce new cultivars. If chimeral breeding techniques were improved, they could become a standard breeding approach for some horticultural crops.  相似文献   

18.
The species of total coliform bacteria isolated from drinking water and untreated surface water by the membrane filter (MF), the standard most-probable-number (S-MPN), and modified most-probable-number (M-MPN) techniques were compared. Each coliform detection technique selected for a different profile of coliform species from both types of water samples. The MF technique indicated that Citrobacter freundii was the most common coliform species in water samples. However, the fermentation tube techniques displayed selectivity towards the isolation of Escherichia coli and Klebsiella. The M-MPN technique selected for more C. freundii and Enterobacter spp. from untreated surface water samples and for more Enterobacter and Klebsiella spp. from drinking water samples than did the S-MPN technique. The lack of agreement between the number of coliforms detected in a water sample by the S-MPN, M-MPN, and MF techniques was a result of the selection for different coliform species by the various techniques.  相似文献   

19.
Traditional techniques for the production of monoclonal antibodies usually result in generation of monoclonal antibodies to immunodominant molecules. To enhance the production of monoclonal antibodies to rare or less immunodominant antigens, subtractive immunization techniques have been employed. This study compared the ability of several subtractive immunization techniques to suppress the immune system to a given antigen. Neonatal tolerization, chemical immunosuppression with cyclophosphamide, a combination of the two and various permutations of these techniques were compared. The results from this study indicated that chemical immunosuppression with cyclophosphamide was the most effective subtractive immunization technique and that the cyclophosphamide regime employed was a critical determinant in the success of chemical immunosuppression.  相似文献   

20.
Acquisition of microarray data is prone to systematic errors. A correction, called normalisation, must be applied to the data before further analysis is performed. With many normalisation techniques published and in use, the best way of executing this correction remains an open question. In this study, a variety of single-slide normalisation techniques, and different parameter settings for these techniques, were compared over many replicated microarray experiments. Different normalisation techniques were assessed through the distribution of the standard deviation of replicates from one biological sample across different slides. It is shown that local normalisation outperformed global normalisation, and intensity-based 'LOWESS' outperformed trimmed mean and median normalisation techniques. Overall, the top performing normalisation technique was a print-tip-based LOWESS with zero robust iterations. Lastly, we validated this evaluation methodology by examining the ability to predict oestrogen receptor-positive and -negative breast cancer samples with data that had been normalised using different techniques.  相似文献   

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