网页方式下的BLAST程序

NCBI BLAST是（Basic Local Alignment Search Tool,局部对比基本检索工具）方便研究工作的优秀工具。介绍BLAST网页方式下的程序,加深用户对BLAST的了解,利用好BLAST。     

Mass spectrometry-based proteomics combined with bioinformatic tools for bacterial classification

Timely classification and identification of bacteria is of vital importance in many areas of public health. We present a mass spectrometry (MS)-based proteomics approach for bacterial classification. In this method, a bacterial proteome database is derived from all potential protein coding open reading frames (ORFs) found in 170 fully sequenced bacterial genomes. Amino acid sequences of tryptic peptides obtained by LC-ESI MS/MS analysis of the digest of bacterial cell extracts are assigned to individual bacterial proteomes in the database. Phylogenetic profiles of these peptides are used to create a matrix of sequence-to-bacterium assignments. These matrixes, viewed as specific assignment bitmaps, are analyzed using statistical tools to reveal the relatedness between a test bacterial sample and the microorganism database. It is shown that, if a sufficient amount of sequence information is obtained from the MS/MS experiments, a bacterial sample can be classified to a strain level by using this proteomics method, leading to its positive identification.     

Protoplasts as tools for plant genome modifications

We present here the application of protoplast technology in the selection and recovery of rare, spontaneous plant genome alterations. Using protoplasts as a cell cloning system allowed the detection and molecular characterization of intrachromosomal recombination events between genomic repeats. The mechanism, frequencies and the induction of intrachromosomal recombination are discussed as well as its application for genome mutagenesis.     

Gene expression profiling in osteoblast biology: bioinformatic tools

This review focuses on using microarray data on a clonal osteoblast cell model to demonstrate how various current and future bioinformatic tools can be used to understand, at a more global or comprehensible level, how cells grow and differentiate. In this example, BMP2 was used to stimulate growth and differentiation of osteoblast to a mineralized matrix. A discussion is included on various methods for clustering gene expression data, statistical evaluation of data, and various new tools that can be used to derive deeper insight into a particular biological problem. How these tools can be obtained is also discussed. New tools for the biologists to compare their datasets with others, as well as examples of future bioinformatic tools that can be used for developing gene networks and pathways for a given set of data are included and discussed.     

Microfluidic tools for quantitative studies of eukaryotic chemotaxis

Over the past decade, microfluidic techniques have been established as a versatile platform to perform live cell experiments under well-controlled conditions. To investigate the directional responses of cells, stable concentration profiles of chemotactic factors can be generated in microfluidic gradient mixers that provide a high degree of spatial control. However, the times for built-up and switching of gradient profiles are in general too slow to resolve the intracellular protein translocation events of directional sensing of eukaryotes. Here, we review an example of a conventional microfluidic gradient mixer as well as the novel flow photolysis technique that achieves an increased temporal resolution by combining the photo-activation of caged compounds with the advantages of microfluidic chambers.     

New tools for quantitative phosphoproteome analysis.

Recent advances in analytical methods, particularly in the area of mass spectrometry, have brought the field of proteomics to the forefront in biological science. The ultimate goal of proteomics--to characterize proteins expressed within a cell under a specific set of conditions--is daunting due to the complexity and dynamic nature the of protein population within the cell. While much of the effort has focused on developing methods to identify expressed proteins, the identification of posttranslational modifications is equally important for comprehensive proteome characterization. Of all the known posttranslational modifications, phosphorylation arguably plays the largest role in the context of cellular homeostasis. This review discusses some of the recent progress made in the development of techniques not only to identify, but also to quantitatively determine sites of phosphorylation.     

New tools for protein sequence analysis.

Analysis of protein sequence is an important tool in studies of both native and recombinant proteins. Novel techniques and instrumentation which facilitate determination of protein primary structure have recently been developed.     

Integration of QTL and bioinformatic tools to identify candidate genes for triglycerides in mice

To identify genetic loci influencing lipid levels, we performed quantitative trait loci (QTL) analysis between inbred mouse strains MRL/MpJ and SM/J, measuring triglyceride levels at 8 weeks of age in F2 mice fed a chow diet. We identified one significant QTL on chromosome (Chr) 15 and three suggestive QTL on Chrs 2, 7, and 17. We also carried out microarray analysis on the livers of parental strains of 282 F2 mice and used these data to find cis-regulated expression QTL. We then narrowed the list of candidate genes under significant QTL using a "toolbox" of bioinformatic resources, including haplotype analysis; parental strain comparison for gene expression differences and nonsynonymous coding single nucleotide polymorphisms (SNP); cis-regulated eQTL in livers of F2 mice; correlation between gene expression and phenotype; and conditioning of expression on the phenotype. We suggest Slc25a7 as a candidate gene for the Chr 7 QTL and, based on expression differences, five genes (Polr3 h, Cyp2d22, Cyp2d26, Tspo, and Ttll12) as candidate genes for Chr 15 QTL. This study shows how bioinformatics can be used effectively to reduce candidate gene lists for QTL related to complex traits.     

Existing bioinformatics tools for the quantitation of post-translational modifications

Mass spectrometry (MS)-based proteomics, by itself, is a vast and complex area encompassing various mass spectrometers, different spectra, and search result representations. When the aim is quantitation performed in different scanning modes at different MS levels, matters become additionally complex. Quantitation of post-translational modifications (PTM) represents the greatest challenge among these endeavors. Many different approaches to quantitation have been described and some of these can be directly applied to the quantitation of PTMs. The amount of data produced via MS, however, makes manual data interpretation impractical. Therefore, specialized software tools meet this challenge. Any software currently able to quantitate differentially labeled samples may theoretically be adapted to quantitate differential PTM expression among samples as well. Due to the heterogeneity of mass spectrometry-based proteomics; this review will focus on quantitation of PTM using liquid chromatography followed by one or more stages of mass spectrometry. Currently available free software, which either allow analysis of PTM or are easily adaptable for this purpose, is briefly reviewed in this paper. Selected studies, especially those related to phosphoproteomics, shall be used to highlight the current ability to quantitate PTMs.     

ALLERDB database and integrated bioinformatic tools for assessment of allergenicity and allergic cross-reactivity

Databases and computational tools are increasingly important in the study of allergies, particularly in the assessment of allergenicity and allergic cross-reactivity. ALLERDB database contains sequences of allergens and information on reported cross-reactivity between allergens. It focuses on analysis of allergenicity and allergic cross-reactivity of clinically relevant protein allergens. The official IUIS allergen data were extracted from the IUIS Allergen Nomenclature Sub-Committee website, and their sequence information from the public databases, and reference publications. The analysis tools assist allergen data analysis and retrieval, and include keyword searching, BLAST, prediction of allergenicity, modification of BLAST that displays cross-reactive allergens, and graphics representation of cross-reactivity data. ALLERDB is new brand of allergen databases with a rich set of tools for sequence comparison, pattern identification, and visualization of results. It is accessible at http://research.i2r.a-star.edu.sg/Templar/DB/Allergen.     

New molecular screening tools for analysis of free-living diazotrophs in soil

Free-living nitrogen-fixing prokaryotes (diazotrophs) are ubiquitous in soil and are phylogenetically and physiologically highly diverse. Molecular methods based on universal PCR detection of the nifH marker gene have been successfully applied to describe diazotroph populations in the environment. However, the use of highly degenerate primers and low-stringency amplification conditions render these methods prone to amplification bias, while less degenerate primer sets will not amplify all nifH genes. We have developed a fixed-primer-site approach with six PCR protocols using less degenerate to nondegenerate primer sets that all amplify the same nifH fragment as a previously published PCR protocol for universal amplification. These protocols target different groups of diazotrophs and allowed for direct comparison of the PCR products by use of restriction fragment length polymorphism fingerprinting. The new protocols were optimized on DNA from 14 reference strains and were subsequently tested with bulk DNA extracts from six soils. These analyses revealed that the new PCR primer sets amplified nifH sequences that were not detected by the universal primer set. Furthermore, they were better suited to distinguish between diazotroph populations in the different soils. Because the novel primer sets were not specific for monophyletic groups of diazotrophs, they do not serve as an identification tool; however, they proved powerful as fingerprinting tools for subsets of soil diazotroph communities.     

SNPHunter: a bioinformatic software for single nucleotide polymorphism data acquisition and management

Background  

Single nucleotide polymorphisms (SNPs) provide an important tool in pinpointing susceptibility genes for complex diseases and in unveiling human molecular evolution. Selection and retrieval of an optimal SNP set from publicly available databases have emerged as the foremost bottlenecks in designing large-scale linkage disequilibrium studies, particularly in case-control settings.     

Use or abuse of bioinformatic tools: a response to Samach

In a recent paper, we described for the first time the effects of fruit on the expression of putative homologues of genes involved in flowering pathways. It was our aim to provide insight into the molecular mechanisms underlying alternate bearing in citrus. However, a bioinformatics-based critique of our and other related papers has been given by Samach in the preceding Viewpoint article in this issue of Annals of Botany. The use of certain bioinformatic tools in a context of structural rather than functional genomics can cast doubts about the veracity of a large amount of data published in recent years. In this response, the contentions raised by Samach are analysed, and rebuttals of his criticisms are presented.     

Genes controlling nucleotide excision repair in eukaryotic cells

The maintenance of genetic integrity is of vital importance to all living organisms. However, DNA – the carrier of genetic information – is continuously subject to damage induced by numerous agents from the environment and endogenous cellular metabolites. To prevent the deleterious consequences of DNA injury, an intricate network of repair systems has evolved. The biological impact of these repair mechanisms is illustrated by a number of genetic diseases that are characterized by a defect in one of the repair machineries and in general predispose individuals to cancer. This article intends to review our current understanding of the complex nucleotide excision repair pathway, a universal repair system with a broad lesion specificity. Emphasis will be on the recent advances in the genetic analysis of this process in mammalian cells.