We present a draft assembly of the genome of European pear (Pyrus communis) `Bartlett'. Our assembly was developed employing second generation sequencing technology (Roche 454), from single-end, 2 ...kb, and 7 kb insert paired-end reads using Newbler (version 2.7). It contains 142,083 scaffolds greater than 499 bases (maximum scaffold length of 1.2 Mb) and covers a total of 577.3 Mb, representing most of the expected 600 Mb Pyrus genome. A total of 829,823 putative single nucleotide polymorphisms (SNPs) were detected using re-sequencing of `Louise Bonne de Jersey' and `Old Home'. A total of 2,279 genetically mapped SNP markers anchor 171 Mb of the assembled genome. Ab initio gene prediction combined with prediction based on homology searching detected 43,419 putative gene models. Of these, 1219 proteins (556 clusters) are unique to European pear compared to 12 other sequenced plant genomes. Analysis of the expansin gene family provided an example of the quality of the gene prediction and an insight into the relationships among one class of cell wall related genes that control fruit softening in both European pear and apple (Malusxdomestica). The `Bartlett' genome assembly v1.0 (http://www.rosaceae.org/species/pyrus/pyrus_communis/genome_v1.0) is an invaluable tool for identifying the genetic control of key horticultural traits in pear and will enable the wide application of marker-assisted and genomic selection that will enhance the speed and efficiency of pear cultivar development.
An iron-regulated gene, pbsC, required for siderophore production in fluorescent Pseudomonas sp. strain M114 has been identified. A kanamycin-resistance cassette was inserted at specific restriction ...sites within a 7 kb genomic fragment of M114 DNA and by marker exchange two siderophore-negative mutants, designated M1 and M2, were isolated. The nucleotide sequence of approximately 4 kb of the region flanking the insertion sites was determined and a large open reading frame (ORF) extending for 2409 bp was identified. This gene was designated pbsC (pseudobactin synthesis C) and its putative protein product termed PbsC. PbsC was found to be homologous to a family of enzymes involved in the biosynthesis of secondary metabolites, including EntF of Escherichia coli. These enzymes are believed to act via ATP-dependent binding of AMP to their substrate. Several areas of high sequence homology between these proteins and PbsC were observed, including a conserved AMP-binding domain. The expression of pbsC is iron-regulated as revealed when a DNA fragment containing the upstream region was cloned in a promoter probe vector and conjugated into the wild-type strain, M114. The nucleotide sequence upstream of the putative translational start site contains a region homologous to previously defined -16 to -25 sequences of iron-regulated genes but did not contain an iron-box consensus sequence. It was noted that inactivation of the pbsC gene also affected other iron-regulated phenotypes of Pseudomonas M114.
A number of anti-H-2 alloantisera containing antibody reactive with I region gene products (Ia) of the major histocompatibility complex cross-react with determinants expressed by human peripheral ...blood B lymphocytes. Such data have led to the conclusion that Ia and DR antigens share cross-reacting determinants. We have attempted to generate mouse primed T lymphocyte populations specific for defined I region gene product determinants which concomitantly recognize DR determinants on human peripheral blood leukocytes in primed lymphocyte typing (PLT) analysis. Mouse PLT cells were generated in primary MLC using strain combinations identical to those in which positive mouse/human cross-reacting antisera have been obtained. The resulting PLT cells exhibited strong, yet specific, secondary MLC responses against mouse cells expressing the Ia determinants used as the primary stimulus. In contrast, when examined on panels of human peripheral blood leukocytes, no reactivity was detected. This lack of cross-reactivity suggests that mouse T cells primed toward Ia determinants do not regularly recognize cross-reacting determinants of DR or D-associated antigens expressed on human PBLs. Consequently, mPLT cells are not a useful reagent in defining HLA-D region polymorphism.
Twenty patients with intractable rheumatoid arthritis were randomized to receive 750 or 2,000 rads of lymphoid irradiation (LI) in a double‐blind comparative study, and were followed for a maximum of ...48 months (mean 40 months) after treatment. During followup, sustained immunomodulation (including lymphopenia, particularly of the T helper cell subset; reduced ratio of helper cells to suppressor cells; and impaired in vitro lymphocyte proliferation in response to phytohemagglutinin and pokeweed mitogen) was observed. Significant improvements in early morning stiffness, Ritchie articular index, pain score, grip strength, and 15‐meter walk time were observed in both treatment groups, but these were not sustained through the followup period. Progressive joint damage was observed radiologically in both groups during followup. Thus, LI induced sustained immunosuppression, but resulted in only shortlived clinical improvement and was associated with progressive joint erosion in these patients.
Immersed in the Caribbean Littlehales, Bates; Kerstitch, Alex; Ireland, Jay ...
Natural history,
10/1988, Letnik:
97, Številka:
10
Magazine Article
Photographers Bates Littlehales, Alex Kerstitch, Jay Ireland, David Doubilet and Chris Newbert capture the flora and fauna of the Caribbean coastal waters on film.
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