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At least 613 records · Page 34Linked to original sources

Survey of transcripts in the adult Drosophila brain.

BACKGROUND: Classic methods of identifying genes involved in neural function include the laborious process of behavioral screening of mutagenized flies and then rescreening candidate lines for pleiotropic effects due to developmental defects. To accelerate the molecular analysis of brain function in Drosophila we constructed a cDNA library exclusively from adult brains. Our goal was to begin to develop a catalog of transcripts expressed in the brain. These transcripts are expected to contain a higher proportion of clones that are involved in neuronal function. RESULTS: The library contains approximately 6.75 million independent clones. From our initial characterization of 271 randomly chosen clones, we expect that approximately 11% of the clones in this library will identify transcribed sequences not found in expressed sequence tag databases. Furthermore, 15% of these 271 clones are not among the 13,601 predicted Drosophila genes. CONCLUSIONS: Our analysis of this unique Drosophila brain library suggests that the number of genes may be underestimated in this organism. This work complements the Drosophila genome project by providing information that facilitates more complete annotation of the genomic sequence. This library should be a useful resource that will help in determining how basic brain functions operate at the molecular level.

Aging↗

Database resources of the National Center for Biotechnology Information.

In addition to maintaining the GenBank nucleic acid sequence database, the National Center for Biotechnology Information (NCBI) provides data retrieval systems and computational resources for the analysis of data in GenBank and other biological data made available through NCBI's website. NCBI resources include Entrez, Entrez Programming Utilities, PubMed, PubMed Central, Entrez Gene, the NCBI Taxonomy Browser, BLAST, BLAST Link (BLink), Electronic PCR, OrfFinder, Spidey, RefSeq, UniGene, HomoloGene, ProtEST, dbMHC, dbSNP, Cancer Chromosomes, Entrez Genomes and related tools, the Map Viewer, Model Maker, Evidence Viewer, Clusters of Orthologous Groups (COGs), Retroviral Genotyping Tools, HIV-1/Human Protein Interaction Database, SAGEmap, Gene Expression Omnibus (GEO), Online Mendelian Inheritance in Man (OMIM), the Molecular Modeling Database (MMDB), the Conserved Domain Database (CDD) and the Conserved Domain Architecture Retrieval Tool (CDART). Augmenting many of the Web applications are custom implementations of the BLAST program optimized to search specialized datasets. All of the resources can be accessed through the NCBI home page at http://www.ncbi.nlm.nih.gov.

Amino Acid Sequence↗

YAC cloning Mus musculus telomeric DNA: physical, genetic, in situ and STS markers for the distal telomere of chromosome 10.

Three Mus musculus DBA/2 YAC libraries were constructed using a half-YAC telomere cloning vector. This functional complementation approach yields libraries which include terminal restriction fragments of the mouse genome. Screening all three libraries led to the isolation of 32 independent clones which carry linear YACs containing the mouse terminal repeat sequence, (TTAGGG)n. These YACs provide a resource to isolate regions of the mouse genome close to chromosome termini and excluded from existing conventional YAC libraries. To demonstrate their utility, a hybridization probe was isolated from Mtel-1, the first (TTAGGG)n-containing YAC isolated. This probe detects a approximately 70 kb Kpnl fragment in the mouse genome which is sensitive to pretreatment with BAL31 exonuclease. A PCR-based genetic marker generated from the sequence of this probe maps 4.4 cM from the most distal anchor locus on chromosome 10 in the EUCIB interspecific backcross. STS primers for this locus, D10Hgu1, were used to isolate YAC 110F4 from a commercially available mouse YAC library. Fluorescence in situ hybridization demonstrates that YAC 110F4 hybridizes to the distal telomere of chromosome 10. Clones in this collection of telomere YACs therefore partially overlap clones in conventional YAC libraries, and thus the previously unavailable terminal regions of the mouse genome can now be linked with the developing mouse STS YAC contig. Genetic markers such as D10Hgu1 allow the ends of the mouse genetic map to be defined, thus closing the map.

Animals↗

Porcine gene discovery by normalized cDNA-library sequencing and EST cluster assembly.

Genetic and environmental factors affect the efficiency of pork production by influencing gene expression during porcine reproduction, tissue development, and growth. The identification and functional analysis of gene products important to these processes would be greatly enhanced by the development of a database of expressed porcine gene sequence. Two normalized porcine cDNA libraries (MARC 1PIG and MARC 2PIG), derived respectively from embryonic and reproductive tissues, were constructed, sequenced, and analyzed. A total of 66,245 clones from these two libraries were 5?-end sequenced and deposited in GenBank. Cluster analysis revealed that within-library redundancy is low, and comparison of all porcine ESTs with the human database suggests that the sequences from these two libraries represent portions of a significant number of independent pig genes. A Porcine Gene Index (PGI), comprising 15,616 tentative consensus sequences and 31,466 singletons, includes all sequences in public repositories and has been developed to facilitate further comparative map development and characterization of porcine genes (http://www.tigr.org/tdb/ssgi/). The clones and sequences from these libraries provide a catalog of expressed porcine genes and a resource for development of high-density hybridization arrays for transcriptional profiling of porcine tissues. In addition, comparison of porcine ESTs with sequences from other species serves as a valuable resource for comparative map development. Both arrayed cDNA libraries are available for unrestricted public use.

Animals↗

Phylogeny for the faint of heart: a tutorial.

Phylogenetic trees seem to be finding ever broader applications, and researchers from very different backgrounds are becoming interested in what they might have to say. This tutorial aims to introduce the basics of building and interpreting phylogenetic trees. It is intended for those wanting to understand better what they are looking at when they look at someone else's trees or to begin learning how to build their own. Topics covered include: how to read a tree, assembling a dataset, multiple sequence alignment (how it works and when it does not), phylogenetic methods, bootstrap analysis and long-branch artefacts, and software and resources.

Amino Acid Sequence↗

Mitochondrial phylogeography and subspecific variation in the red panda (Ailurus fulgens): implications for conservation.

The red panda (Ailurus fulgens) is an endangered species and its present distribution is restricted to isolated mountain ranges in western China (Sichuan, Yunnan, and Tibet provinces) and the Himalayan Mountains chain of Nepal, India, Bhutan, and Burma. To examine the evolutionary history across its current range, and to assess the genetic divergence among current subspecies and population structure among different geographic locations, we sequenced mitochondrial DNA from the control region (CR) and cytochrome (cyt) b gene for 41 individuals in Sichuan, Yunnan, Tibet of China, and Burma. 25 CR haplotypes (10 for cyt b) were identified from 11 geographic locations. Only three haplotypes were shared among sample localities, including one among current subspecies. Nine haplotypes were shared with the study of Su et al. [Mol. Biol. Evol. 18 (2001) 1070]. CR haplotype diversity was high (0.95+/-0.02) and nucleotide diversity among all haplotypes was relatively low (0.018+/-0.009). Phylogenetic confirmed trees show a shallow pattern with very little structure or statistical robustness. The application of two coalescent-based tests for population growth allowed us to interpret this phylogeny as the result of a recent population expansion. Analysis of molecular variance and nested clade analysis failed to detect significant geographic structure in both data sets. The lack of significant differentiation between subspecies does not indicate the presence of evolutionary significant units. We suggest that the present population structure has resulted from habitat fragmentation and expansion from glacial refugia. Due to its habitat requirements it is likely that the red panda has undergone bottlenecks and population expansions several times in the recent past. The present population may exhibit a pattern reminiscent of a relatively recent population expansion.

Animals↗

Genetic evaluation of a proposed introduction: the case of the greater prairie chicken and the extinct heath hen.

Population introduction is an important tool for ecosystem restoration. However, before introductions should be conducted, it is important to evaluate the genetic, phenotypic and ecological suitability of possible replacement populations. Careful genetic analysis is particularly important if it is suspected that the extirpated population was unique or genetically divergent. On the island of Martha's Vineyard, Massachusetts, the introduction of greater prairie chickens (Tympanuchus cupido pinnatus) to replace the extinct heath hen (T. cupido cupido) is being considered as part of an ecosystem restoration project. Martha's Vineyard was home to the last remaining heath hen population until its extinction in 1932. We conducted this study to aid in determining the suitability of greater prairie chickens as a possible replacement for the heath hen. We examined mitochondrial control region sequences from extant populations of all prairie grouse species (Tympanuchus) and from museum skin heath hen specimens. Our data suggest that the Martha's Vineyard heath hen population represents a divergent mitochondrial lineage. This result is attributable either to a long period of geographical isolation from other prairie grouse populations or to a population bottleneck resulting from human disturbance. The mtDNA diagnosability of the heath hen contrasts with the network of mtDNA haplotypes of other prairie grouse (T. cupido attwateri, T. pallidicinctus and T. phasianellus), which do not form distinguishable mtDNA groupings. Our findings suggest that the Martha's Vineyard heath hen was more genetically isolated than are current populations of prairie grouse and place the emphasis for future research on examining prairie grouse adaptations to different habitat types to assess ecological exchangeability between heath hens and greater prairie chickens.

Animals↗

Worldwide structure of mtDNA diversity among Cuvier's beaked whales (Ziphius cavirostris): implications for threatened populations.

We present the first description of phylogeographic structure among Cuvier's beaked whales (Ziphius cavirostris) worldwide using mitochondrial DNA (mtDNA) control region sequences obtained from strandings (n = 70), incidental fisheries takes (n = 11), biopsy (n = 1), and whale-meat markets (n = 5). Over a 290-base pair fragment, 23 variable sites defined 33 unique haplotypes among the total of 87 samples. Nucleotide diversity at the control region was relatively low (pi = 1.27%+/- 0.723%) compared to wide-ranging baleen whales, but higher than strongly matrifocal sperm, pilot and killer whales. Phylogenetic reconstruction using maximum likelihood revealed four distinct haplotype groups, each of which displayed strong frequency differences among ocean basins, but no reciprocal monophyly or fixed character differences. Consistent with this phylogeographic pattern, an analysis of molecular variance showed high levels of differentiation among ocean basins (F(ST) = 0.14, Phi ST = 0.42; P < 0.001). Estimated rates of female migration among ocean basins were low (generally < or = 2 individuals per generation). Regional sample sizes were too small to detect subdivisions within oceans except in the North Atlantic, where the Mediterranean Sea (n = 12) was highly differentiated due to the presence of two private haplotypes. One market product purchased in South Korea grouped with other haplotypes found only in the North Atlantic, suggesting a violation of current agreements banning international trade in cetacean species. Together, these results demonstrate a high degree of isolation and low maternal gene flow among oceanic, and in some cases, regional populations of Cuvier's beaked whales. This has important implications for understanding the threats of human impact, including fisheries by-catch, direct hunting, and disturbance or mortality from anthropogenic sound.

Analysis of Variance↗

Genetic isolation and divergence in sexual traits: evidence for the northern rockhopper penguin Eudyptes moseleyi being a sibling species.

The taxonomic status of populations of rockhopper penguins (Eudyptes chrysocome) is still enigmatic. Northern populations differ from southern ones in breeding phenology, song characteristics and head ornaments used as mating signals. We conducted a molecular analysis using mitochondrial DNA sequencing to test if there is a gene flow barrier between northern (subtropical) populations and southern (subantarctic) populations in relation to the Subtropical Convergence, a major ecological boundary for marine organisms. Sequences of the control region and the ND2 gene were analysed in rockhopper penguins and in the macaroni penguin (Eudyptes chrysolophus), a closely related species. Genetic distances and phylogenetic analyses showed a clear split into three clades, two rockhopper clades and the macaroni penguin. Moreover, Theta(ST) and gene flow estimates also suggested genetic structuring within the northern rockhoppers. Our results add further support to the notion that the two rockhopper penguin taxa, often considered as two subspecies, can be recognized as two species E. chrysocome and E. moseleyi. The divergence in mating signals found between these two taxa seems to have occurred recently and relatively rapidly. Thus, the behavioural changes may have been enough to isolate these taxa without the need for morphological differentiation. The findings have important conservational implications, since E. moseleyi is far less abundant than E. chrysocome, but more populations may warrant an uplisting to endangered status if full species status should be recognized for more subpopulations.

Animals↗

The EMBL Nucleotide Sequence Database.

The EMBL Nucleotide Sequence Database (aka EMBL-Bank; http://www.ebi.ac.uk/embl/) incorporates, organises and distributes nucleotide sequences from all available public sources. EMBL-Bank is located and maintained at the European Bioinformatics Institute (EBI) near Cambridge, UK. In an international collaboration with DDBJ (Japan) and GenBank (USA), data are exchanged amongst the collaborating databases on a daily basis. Major contributors to the EMBL database are individual scientists and genome project groups. Webin is the preferred web-based submission system for individual submitters, whilst automatic procedures allow incorporation of sequence data from large-scale genome sequencing centres and from the European Patent Office (EPO). Database releases are produced quarterly. Network services allow free access to the most up-to-date data collection via FTP, email and World Wide Web interfaces. EBI's Sequence Retrieval System (SRS), a network browser for databanks in molecular biology, integrates and links the main nucleotide and protein databases plus many other specialized databases. For sequence similarity searching, a variety of tools (e.g. Blitz, Fasta, BLAST) are available which allow external users to compare their own sequences against the latest data in the EMBL Nucleotide Sequence Database and SWISS-PROT. All resources can be accessed via the EBI home page at http://www.ebi.ac.uk.

Animals↗

The EMBL Nucleotide Sequence Database: major new developments.

The EMBL Nucleotide Sequence Database (http://www.ebi.ac.uk/embl/) incorporates, organizes and distributes nucleotide sequences from all available public sources. The database is located and maintained at the European Bioinformatics Institute (EBI) near Cambridge, UK. In an international collaboration with DDBJ (Japan) and GenBank (USA), data are exchanged amongst the collaborating databases on a daily basis to achieve optimal synchronization. Webin is the preferred web-based submission system for individual submitters, while automatic procedures allow incorporation of sequence data from large-scale genome sequencing centres and from the European Patent Office (EPO). Database releases are produced quarterly. Network services allow free access to the most up-to-date data collection via FTP, Email and World Wide Web interfaces. EBI's Sequence Retrieval System (SRS) integrates and links the main nucleotide and protein databases plus many other specialized molecular biology databases. For sequence similarity searching, a variety of tools (e.g. Fasta, BLAST) are available which allow external users to compare their own sequences against the latest data in the EMBL Nucleotide Sequence Database and SWISS-PROT. All resources can be accessed via the EBI home page at http://www.ebi.ac.uk.

Animals↗

Rat testin is a newly identified component of the junctional complexes in various tissues whose mRNA is predominantly expressed in the testis and ovary.

Testin I and testin II are the two molecular variants of testin that are synthesized and secreted by Sertoli cells in vitro. N-Terminal and partial internal amino acid sequence analysis of testin I and testin II reveals that these molecules are identical with the exception that testin II has three extra N-terminal amino acids of TAP compared to testin I. Studies using immunohistochemistry suggested that testin is a component of the specialized junctional complexes in the seminiferous epithelium and other tissues. Immunoreactive testin is localized not only at Sertoli-Sertoli and Sertoli-germ cell junctions, but also at sites of similar junctions in the liver, epididymis, kidney, and intestine. Other physiological studies have shown that the secretion of testin is tightly coupled to the presence of germ cells. In view of its possible role in germ cell development and its unique localization in the cell junction, the purpose of the present study was to determine the structure of testin by sequencing its full-length cDNA. Two synthetic degenerate oligonucleotides based on the N-terminal and an internal amino acid sequence were used for polymerase chain reaction (PCR) to obtain a 289-bp cDNA fragment. This PCR product was subsequently used to isolate a 1371-bp cDNA from a cDNA expression library constructed from Sertoli cell poly(A) RNA. This cDNA coded for a 333 amino acid peptide that starts with an ATG initiation codon from the 5' end and ends with a TGA termination codon located 245 nucleotides before the polyadenylation site. The deduced amino acid sequence indicates that testin contains a 16 amino acid signal peptide with two possible cleavage sites that yield 314 and 317 amino acids for testin I and testin II with calculated molecular weights of 36,029 and 36,299, respectively. Comparison of the entire coding region of testin with existing sequences at Genbank, EMBL, and Protein Identification Resource indicates that testin shares 58%, 57.4%, and 61% identity with rat, mouse, and human cathepsin L at the amino acid level, respectively. The positions of all of the 7 Cys residues and 8 of the 10 Trp residues in testin are conserved with respect to those present in cathepsin L. It is noted that Cys-122 in the predicted active site of cathepsin L was replaced with Ser-122 in testin. In view of the striking primary sequence homology between testin and cathepsin L, we assayed the proteolytic activity of testin using conditions known to activate cathepsin L.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗

Cortical and cerebellar activity of the human brain during imagined and executed unimanual and bimanual action sequences: a functional MRI study.

The neural (blood oxygenation level dependent) correlates of executed and imagined finger sequences, both unimanual and bimanual, were studied in adult right-handed volunteers using functional magnetic resonance imaging (fMRI) of the entire brain. The finger to thumb opposition tasks each consisted of three conditions, two unimanual and one bimanual. Each experimental condition consisted of overt movement of the fingers in a prescribed sequence and imagery of the same task. An intricate network consisting of sensorimotor cortex, supplementary motor area (SMA), superior parietal lobule and cerebellum was identified when the tasks involved both planning and execution. During imagery alone, however, cerebellar activity was largely absent. This apparent decoupling of sensorimotor cortical and cerebellar areas during imagined movement sequences, suggests that cortico-cerebellar loops are engaged only when action sequences are both intended and realized. In line with recent models of motor control, the cerebellum may monitor cortical output and feed back corrective information to the motor cortex primarily during actual, not imagined, movements. Although parietal cortex activation occurred during both execution and imagery tasks, it was most consistently present during bimanual action sequences. The engagement of the superior parietal lobule appears to be related to the increased attention and memory resources associated, in the present instance, with coordinating difficult bimanual sequences.

Adult↗

Lipase localization in Rhizopus oryzae cells immobilized within biomass support particles for use as whole-cell biocatalysts in biodiesel-fuel production.

To identify the lipase responsible for the methanolysis activity of fungus whole-cell biocatalysts, the lipase localization of Rhizopus oryzae cells was determined. Western blot analysis showed that R. oryzae cells produce two types of lipase with different molecular masses of 34 and 31 kDa; the former (ROL34) was bound to the cell wall, whereas the latter (ROL31) was mainly bound to the cell membrane. It was found that cell immobilization within reticulated polyurethane foam biomass support particles strongly inhibits the secretion of membrane-bound lipase into the culture medium. An investigation of the relationship between ROL34 and ROL31 suggested that ROL31 originates from the cleavage of a 28-amino-acid residue at the N-terminus of ROL34. The addition of olive oil to the culture medium led to the retention of increased amounts of lipase within the cell. This phenomenon was further confirmed by an immunofluorescence labeling of hyphal cells. When cells were cultivated with various substrate-related compounds, such as olive oil and oleic acid, the intracellular methanolysis activity strongly correlated with the relative amounts of the membrane-bound lipase, which suggests that ROL31 localized in the membrane plays a crucial role in the methanolysis activity of R. oryzae cells.

Amino Acid Sequence↗

A prime number approach to biological sequencing.

Computational sequencing of nucleic acid and amino acid sequences is placing increasing demands on computer resources. The use of prime numbers is explored as a convenient means of improving program speed and reducing storage requirements. It is concluded that the application of the prime number approach leads to significant increases in speed and some reduction in storage requirements.

Amino Acid Sequence↗

Genetic and physical characterization of the early-onset Alzheimer's disease AD3 locus on chromosome 14q24.3.

Genetic linkage studies have provided significant evidence that a major gene defect, AD3, for familial early-onset Alzheimer's disease (EOAD) is located at chromosome 14q24.3, between the short tandem repeat (STR) markers D14S52 and D14S53 defining a genetic size of 22.7 cM for the AD3 candidate region. We constructed a physical map of the AD3 region using yeast artificial chromosomes (YACs) selected from both the CEPH and megaCEPH YAC libraries using the AD3 linked STR markers as well as new sequence-tagged sites (STSs) designed based on YAC terminal sequences. The YAC map is contiguous in the region between D14S258 and D14S53, a region of 8.2 cM, and has an estimated physical size of 4-8 Mb. The YAC contig map was used as a framework to localize three known genes, a pseudogene and two brain expressed sequence tags (ESTs). Linkage analysis studies in two Belgian chromosome 14 EOAD families AD/A and AD/B, identified obligate recombinants in family AD/A with D14S289 and D14S61 reducing the genetic size of the candidate AD3 region substantially. The minimal AD3 candidate region measured 6.4 cM on the genetic map and is contained within six overlapping megaCEPH YACs that covered a physical distance estimated between 2 and 6 Mb. These YACs as well as other YACs in the YAC contig map are valuable resources in gene cloning efforts or genomic sequencing experiments aiming at isolating the AD3 gene.

Age of Onset↗

Whole-Genome Sequencing of 54 Dengchuan Cattle (Bos taurus) from Southwest China.

Domestic cattle (Bos taurus) play a significant role in human society as they provide abundant food resources and contribute to the development of agriculture and traditional culture. Dengchuan cattle, a local breed from Yunnan, Southwest China, are known for their high-quality milk and are at risk of extinction due to crossbreeding. To preserve the superior genetic resources of Dengchuan cattle, this study conducted whole-genome sequencing of 54 Dengchuan cattle using blood DNA samples, generating approximately 3.56 TB of clean data with an average sequencing depth of 32.78X. The sequencing data were aligned to the bovine reference genome (ARS-UCD2.0), achieving an average alignment rate of 99.85%. A total of 9,950,420 SNPs and 2,476,207 indels were detected using variant calling workflow. These data were utilized to characterize genomic profile of this unique cattle breed. The data generated in this study can be incorporated into the global cattle genomic diversity database, providing valuable information for comparative studies on cattle.

Animals↗

The endosymbiotic origin of the protein import machinery of chloroplastic envelope membranes.

Chloroplasts have evolved a complex proteinaceous machinery to import nuclear-encoded proteins. The origin of this machinery, following the endosymbiotic events leading to chloroplasts, is an intriguing, unresolved problem. Given that cyanobacteria are the probable ancestors of chloroplasts, the genome sequence of Synechocystis sp. PCC 6803 offers a valuable resource to identify putative homologs for components of this protein import machinery and to gain insights into its possibly endosymbiotic origin. Detailed computational sequence analysis reveals that Synechocystis sp. PCC 6803 has homologs of three of the known membrane proteins of the chloroplastic translocon, namely Toc75, Tic20 and Tic22, as well as a homolog of the putative component Tic55. Thus, the chloroplastic protein import machinery is mainly derived from the endosymbiotic cyanobacterium, but, interestingly, not from any of the four main protein secretion systems of prokaryotes. The relatively high sequence variability between chloroplastic and Synechocystis proteins suggests that the ancestral proteins had different physiological roles and were modified significantly to fulfill the new demand of importing proteins into the evolving chloroplast. The fact that some chloroplastic protein import components are not related to any Synechocystis proteins (Toc159, Tic110 and Toc34) indicates that the chloroplastic protein import apparatus is of a dual evolutionary origin.

Journal Article↗