566 research outputs found

    MARTA East Line Tunnels under I-285, Atlanta, Georgia

    Get PDF
    The Metropolitan Atlanta Rapid Transit Authority combined three new technologies − microtunneling, jet grouting, and rock-socketed minipiles − to successfully construct twin rail tunnels under an eight-lane highway with as little as 4-1/2 feet of cover. Geotechnical parameters, tunneling method selection, and construction methods are discussed. Ground response and monitoring are summarized

    Changes in Temporal and Spatial Patterns of Outer Surface Lipoprotein Expression Generate Population Heterogeneity and Antigenic Diversity in the Lyme Disease Spirochete, Borrelia burgdorferi

    Get PDF
    This is the published version. Copyright 2015 by the American Society for Microbiology.Borrelia burgdorferi differentially expresses many of the OspE/F/Elp paralogs during tick feeding. These findings, combined with the recent report that stable B. burgdorferi infection of mammals occurs only after 53 h of tick attachment, prompted us to further analyze the expression of the OspE/F/Elp paralogs during this critical period of transmission. Indirect immunofluorescence analysis revealed that OspE, p21, ElpB1, ElpB2, and OspF/BbK2.11 are expressed in the salivary glands of ticks allowed to feed on mice for 53 to 58 h. Interestingly, many of the spirochetes in the salivary glands that expressed abundant amounts of these antigens were negative for OspA and OspC. Although prior reports have indicated that OspE/F/Elp orthologs are surface exposed, none of the individual lipoproteins or combinations of the lipoproteins protected mice from challenge infections. To examine why these apparently surface-exposed lipoproteins were not protective, we analyzed their genetic stability during infection and their cellular locations after cultivation in vitro and within dialysis membrane chambers, mimicking a mammalian host-adapted state. Combined restriction fragment length polymorphism and nucleotide sequence analyses revealed that the genes encoding these lipoproteins are stable for at least 8 months postinfection. Interestingly, cellular localization experiments revealed that while all of these proteins can be surface localized, there were significant populations of spirochetes that expressed these lipoproteins only in the periplasm. Furthermore, host-specific signals were found to alter the expression patterns and final cellular location of these lipoproteins. The combined data revealed a remarkable heterogeneity in populations of B. burgdorferi during tick transmission and mammalian infection. The diversity is generated not only by temporal changes in antigen expression but also by modulation of the surface lipoproteins during infection. The ability to regulate the temporal and spatial expression patterns of lipoproteins throughout infection likely contributes to persistent infection of mammals by B. burgdorferi

    Regulation of OspE-Related, OspF-Related, and Elp Lipoproteins of Borrelia burgdorferi Strain 297 by Mammalian Host-Specific Signals

    Get PDF
    This is the published version. Copyright 2001 by the American Society for Microbiology.In previous studies we have characterized the cp32/18 loci inBorrelia burgdorferi 297 which encode OspE and OspF orthologs and a third group of lipoproteins which possess OspE/F-like leader peptides (Elps). To further these studies, we have comprehensively analyzed their patterns of expression throughout the borrelial enzootic cycle. Serial dilution reverse transcription-PCR analysis indicated that although a shift in temperature from 23 to 37°C induced transcription for all nine genes analyzed, this effect was often markedly enhanced in mammalian host-adapted organisms cultivated within dialysis membrane chambers (DMCs) implanted within the peritoneal cavities of rats. Indirect immunofluorescence assays performed on temperature-shifted, in vitro-cultivated spirochetes and organisms in the midguts of unfed and fed ticks revealed distinct expression profiles for many of the OspE-related, OspF-related, and Elp proteins. Other than BbK2.10 and ElpA1, all were expressed by temperature-shifted organisms, while only OspE, ElpB1, OspF, and BbK2.11 were expressed in the midguts of fed ticks. Additionally, although mRNA was detected for all nine lipoprotein-encoding genes, two of these proteins (BbK2.10 and ElpA1) were not expressed by spirochetes cultivated in vitro, within DMCs, or by spirochetes within tick midguts. However, the observation that B. burgdorferi-infected mice generated specific antibodies against BbK2.10 and ElpA1 indicated that these antigens are expressed only in the mammalian host and that a form of posttranscriptional regulation is involved. Analysis of the upstream regions of these genes revealed several differences between their promoter regions, the majority of which were found in the −10 and −35 hexamers and the spacer regions between them. Also, rather than undergoing simultaneous upregulation during tick feeding, these genes and the corresponding lipoproteins appear to be subject to progressive recruitment or enhancement of expression as B. burgdorferi is transmitted from its tick vector to the mammalian host. These findings underscore the potential relevance of these molecules to the pathogenic events of early Lyme disease

    Genetic Improvement of Pearl Millet for Grain and Forage Production: Cytogenetic Manipulation and Heterosis Breeding

    Get PDF
    Pearl millet, Pennisetum glaucum (L.) R. Brown (= Pennisetum typhoides (Burm.) Stapf et Hubb.), is the most important member of the genus Pennisetum of the tribe Paniceae in the family Poaceae. The name Pennisetum was derived as a hybrid of two Latin words — penna , meaning feather, and seta , meaning bristle — and describes the typically feathery bristles of its species (Jauhar 1981a). Pearl millet is the sixth most important cereal crop in the world, ranking after wheat, rice, maize, barley, and sorghum. It is a valuable grain and fodder crop and is cultivated in many parts of the world, although in the U.S. it is grown primarily as a forage crop on less than 1 million ha. In tropical and warm-temperature regions of Australia and some other countries, it is also grown as a forage crop (Jauhar 1981a). Pearl millet is an ideal organism for basic and applied research. In their extensive reviews, Jauhar (1981a) and Jauhar and Hanna (1998) compiled the available literature on cytogenetics and breeding of pearl millet and related species. This article covers some basic aspects of cytogenetics of pearl millet, its cytogenetic manipulation with a view to enrich it with alien genes, aspects of heterosis breeding facilitated by the cytoplasmic-nuclear male sterility (CMS) system and possibly by apomixis, and direct gene transfer into otherwise superior cultivars

    Phenotype-specific association of the TGFBR3 locus with nonsyndromic cryptorchidism

    Get PDF
    PURPOSE: Based on a genome-wide association study of testicular dysgenesis syndrome showing a possible association with TGFBR3, we analyzed data from a larger, phenotypically restricted cryptorchidism population for potential replication of this signal. MATERIALS AND METHODS: We excluded samples based on strict quality control criteria, leaving 844 cases and 2,718 controls of European ancestry that were analyzed in 2 separate groups based on genotyping platform (ie Illumina® HumanHap550, version 1 or 3, or Human610-Quad, version 1 BeadChip in group 1 and Human OmniExpress 12, version 1 BeadChip platform in group 2). Analyses included genotype imputation at the TGFBR3 locus, association analysis of imputed data with correction for population substructure, subsequent meta-analysis of data for groups 1 and 2, and selective genotyping of independent cases (330) and controls (324) for replication. We also measured Tgfbr3 mRNA levels and performed TGFBR3/betaglycan immunostaining in rat fetal gubernaculum. RESULTS: We identified suggestive (p ≤ 1× 10(-4)) association of markers in/near TGFBR3, including rs9661103 (OR 1.40; 95% CI 1.20, 1.64; p = 2.71 × 10(-5)) and rs10782968 (OR 1.58; 95% CI 1.26, 1.98; p = 9.36 × 10(-5)) in groups 1 and 2, respectively. In subgroup analyses we observed strongest association of rs17576372 (OR 1.42; 95% CI 1.24, 1.60; p = 1.67 × 10(-4)) with proximal and rs11165059 (OR 1.32; 95% CI 1.15, 1.38; p = 9.42 × 10(-4)) with distal testis position, signals in strong linkage disequilibrium with rs9661103 and rs10782968, respectively. Association of the prior genome-wide association study signal (rs12082710) was marginal (OR 1.13; 95% CI 0.99, 1.28; p = 0.09 for group 1), and we were unable to replicate signals in our independent cohort. Tgfbr3/betaglycan was differentially expressed in wild-type and cryptorchid rat fetal gubernaculum. CONCLUSIONS: These data suggest complex or phenotype specific association of cryptorchidism with TGFBR3 and the gubernaculum as a potential target of TGFβ signaling

    Nested‐association mapping (NAM)‐based genetic dissection uncovers candidate genes for seed and pod weights in peanut ( Arachis hypogaea )

    Get PDF
    Multiparental genetic mapping populations such as nested-association mapping (NAM) havegreat potential for investigating quantitative traits and associated genomic regions leading torapid discovery of candidate genes and markers. To demonstrate the utility and power of thisapproach, two NAM populations, NAM_Tifrunner and NAM_Florida-07, were used for dissectinggenetic control of 100-pod weight (PW) and 100-seed weight (SW) in peanut. Two high-densitySNP-based genetic maps were constructed with 3341 loci and 2668 loci for NAM_Tifrunner andNAM_Florida-07, respectively. The quantitative trait locus (QTL) analysis identified 12 and 8major effect QTLs for PW and SW, respectively, in NAM_Tifrunner, and 13 and 11 major effectQTLs for PW and SW, respectively, in NAM_Florida-07. Most of the QTLs associated with PW andSW were mapped on the chromosomes A05, A06, B05 and B06. A genomewide associationstudy (GWAS) analysis identified 19 and 28 highly significant SNP–trait associations (STAs) inNAM_Tifrunner and 11 and 17 STAs in NAM_Florida-07 for PW and SW, respectively. Thesesignificant STAs were co-localized, suggesting that PW and SW are co-regulated by severalcandidate genes identified on chromosomes A05, A06, B05, and B06. This study demonstratesthe utility of NAM population for genetic dissection of complex traits and performing high-resolution trait mapping in peanut

    Indications of decreasing human PTS concentrations in North West Russia

    Get PDF
    The Russian Arctic covers an enormous landmass with diverse environments. It inhabits more than 20 different ethnic groups, all of them with various living conditions and food traditions. Indigenous populations with a traditional way of living are exposed to a large number of anthropogenic pollutants, such as persistent organic pollutants (POPs) and toxic metals, mainly through the diet. Human monitoring of persistent organic pollutants (POPs) and heavy metals in the Russian Arctic has only been performed on irregular intervals over the past 15 years, thus, there is still a lack of baseline data from many ethnic groups and geographical regions. The aim of the current study was to investigate concentrations of POPs and toxic metals in three groups of indigenous people from the Russian Arctic. Plasma concentrations of POPs were measured in one of the locations (Nelmin-Nos) in 2001–2003 which gave the unique opportunity to compare concentrations over time in a small Russian arctic community. During 2009 and early 2010, 209 blood samples were collected from three different study sites in North West Russia; Nelmin-Nos, Izhma and Usinsk. The three study sites are geographically separated and the inhabitants are expected to have different dietary habits and living conditions. All blood samples were analyzed for POPs and toxic metals. PCB 153 was present in highest concentrations of the 18 PCBs analyzed. p,p′-DDE and HCB were the two most dominating OC pesticides. Males had higher concentrations of PCB 138, 153 and 180 than women and age was a significant predictor of PCB 153, 180, HCB and p,p′-DDD. Males from Izhma had significantly higher concentrations of HCB than males from the other study sites and women from Usinsk had higher concentrations of p,p′-DDE. Parity was a significant predictor of p,p′-DDE. Hg and Pb concentrations increased with increasing age and males had significantly higher concentrations of Pb than women. The study group from Izhma had significantly higher concentrations of Cd when controlling for age and gender and the study group from Usinsk had higher concentrations of Se than the others. Compared to the results from Nelmin-Nos in 2001–2003, a clear decrease in p,p′-DDE concentrations for both women and men was observed. The current study indicates a significant reduction of several PTSs in human blood samples from North West Russia over the past 10 years

    Identification of ovule transcripts from the Apospory-Specific Genomic Region (ASGR)-carrier chromosome

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Apomixis, asexual seed production in plants, holds great potential for agriculture as a means to fix hybrid vigor. Apospory is a form of apomixis where the embryo develops from an unreduced egg that is derived from a somatic nucellar cell, the aposporous initial, via mitosis. Understanding the molecular mechanism regulating aposporous initial specification will be a critical step toward elucidation of apomixis and also provide insight into developmental regulation and downstream signaling that results in apomixis. To discover candidate transcripts for regulating aposporous initial specification in <it>P. squamulatum</it>, we compared two transcriptomes derived from microdissected ovules at the stage of aposporous initial formation between the apomictic donor parent, <it>P. squamulatum </it>(accession PS26), and an apomictic derived backcross 8 (BC<sub>8</sub>) line containing only the Apospory-Specific Genomic Region (ASGR)-carrier chromosome from <it>P. squamulatum</it>. Toward this end, two transcriptomes derived from ovules of an apomictic donor parent and its apomictic backcross derivative at the stage of apospory initiation, were sequenced using 454-FLX technology.</p> <p>Results</p> <p>Using 454-FLX technology, we generated 332,567 reads with an average read length of 147 base pairs (bp) for the PS26 ovule transcriptome library and 363,637 reads with an average read length of 142 bp for the BC<sub>8 </sub>ovule transcriptome library. A total of 33,977 contigs from the PS26 ovule transcriptome library and 26,576 contigs from the BC<sub>8 </sub>ovule transcriptome library were assembled using the Multifunctional Inertial Reference Assembly program. Using stringent <it>in silico </it>parameters, 61 transcripts were predicted to map to the ASGR-carrier chromosome, of which 49 transcripts were verified as ASGR-carrier chromosome specific. One of the alien expressed genes could be assigned as tightly linked to the ASGR by screening of apomictic and sexual F<sub>1</sub>s. Only one transcript, which did not map to the ASGR, showed expression primarily in reproductive tissue.</p> <p>Conclusions</p> <p>Our results suggest that a strategy of comparative sequencing of transcriptomes between donor parent and backcross lines containing an alien chromosome of interest can be an efficient method of identifying transcripts derived from an alien chromosome in a chromosome addition line.</p

    Development and Evaluation of a High Density Genotyping ‘Axiom_Arachis’ Array with 58 K SNPs for Accelerating Genetics and Breeding in Groundnut

    Get PDF
    Single nucleotide polymorphisms (SNPs) are the most abundant DNA sequence variation in the genomes which can be used to associate genotypic variation to the phenotype. Therefore, availability of a high-density SNP array with uniform genome coverage can advance genetic studies and breeding applications. Here we report the development of a high-density SNP array ‘Axiom_Arachis’ with 58 K SNPs and its utility in groundnut genetic diversity study. In this context, from a total of 163,782 SNPs derived from DNA resequencing and RNA-sequencing of 41 groundnut accessions and wild diploid ancestors, a total of 58,233 unique and informative SNPs were selected for developing the array. In addition to cultivated groundnuts (Arachis hypogaea), fair representation was kept for other diploids (A. duranensis, A. stenosperma, A. cardenasii, A. magna and A. batizocoi). Genotyping of the groundnut ‘Reference Set’ containing 300 genotypes identified 44,424 polymorphic SNPs and genetic diversity analysis provided in-depth insights into the genetic architecture of this material. The availability of the high-density SNP array ‘Axiom_Arachis’ with 58 K SNPs will accelerate the process of high resolution trait genetics and molecular breeding in cultivated groundnut
    corecore