820 research outputs found

    Expendable oceanographic mooring (XMOOR)

    Get PDF
    An expendable, self-deploying mooring (XMOOR) for shallow water applications has been developed to address Navy requirements for environmental monitoring. The project has been conducted jointly between the Woods Hole Oceanographic Institution and the Naval Research Laboratory at Stennis, MS. WHOI has taken the lead on the mechanical design of the system while NR has developed the electronics. Eight prototype XMOOR systems have been built. They are designed for water depths between 10 and 100m, for deployments of up to 3-months duration, and for automatic deployment. Their sensor suite includes barometrc pressure, air temperatue, water temperature at up to 25 levels, and conductivity and pressure at up to 3 levels. Data telemetry is accomplished via the Argos DCS and by line-of-sight VH confguration of the data collection program. This report describes the XMOOR mechanical system. The data collection and telemetry systems are described separately in (1) and (2).Funding was provided by the Office of Naval Research through Contract Nos. NOOO-14-92-C-6028 and NOOO-14-95-1-0774

    Survival of Burkholderia pseudomallei in Water

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The ability of <it>Burkholderia pseudomallei </it>to survive in water likely contributes to its environmental persistence in endemic regions. To determine the physiological adaptations which allow <it>B. pseudomallei </it>to survive in aqueous environments, we performed microarray analyses of <it>B. pseudomallei </it>cultures transferred from Luria broth (LB) to distilled water.</p> <p>Findings</p> <p>Increased expression of a gene encoding for a putative membrane protein (BPSL0721) was confirmed using a <it>lux</it>-based transcriptional reporter system, and maximal expression was noted at approximately 6 hrs after shifting cells from LB to water. A BPSL0721 deficient mutant of <it>B. pseudomallei </it>was able to survive in water for at least 90 days indicating that although involved, BPSL0721 was not essential for survival. BPSL2961, a gene encoding a putative phosphatidylglycerol phosphatase (PGP), was also induced when cells were shifted to water. This gene is likely involved in cell membrane biosynthesis. We were unable to construct a PGP mutant suggesting that the gene is not only involved in survival in water but is essential for cell viability. We also examined mutants of polyhydroxybutyrate synthase (<it>phb</it>C), lipopolysaccharide (LPS) oligosaccharide and capsule synthesis, and these mutations did not affect survival in water. LPS mutants lacking outer core were found to lose viability in water by 200 days indicating that an intact LPS core provides an outer membrane architecture which allows prolonged survival in water.</p> <p>Conclusion</p> <p>The results from these studies suggest that <it>B. pseudomallei </it>survival in water is a complex process that requires an LPS molecule which contains an intact core region.</p

    Ten year change in forest succession and composition measured by remote sensing

    Get PDF
    Vegetation dynamics and changes in ecological patterns were measured by remote sensing over a 10 year period (1973 to 1983) for 148,406 landscape elements, covering more than 500 sq km in a protected forested wilderness. Quantitative measurements were made possible by methods to detect ecologically meaningful landscape units; these allowed measurement of ecological transition frequencies and calculation of expected recurrence times. Measured ecological transition frequencies reveal boreal forest wilderness as spatially heterogeneous and highly dynamic, with one-sixth of the area in clearings and early successional stages, consistent with recent postulates about the spatial and temporal patterns of natural ecosystems. Differences between managed forest areas and a protected wilderness allow assessment of different management regimes

    Burkholderia thailandensis harbors two identical rhl gene clusters responsible for the biosynthesis of rhamnolipids

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Rhamnolipids are surface active molecules composed of rhamnose and β-hydroxydecanoic acid. These biosurfactants are produced mainly by <it>Pseudomonas aeruginosa </it>and have been thoroughly investigated since their early discovery. Recently, they have attracted renewed attention because of their involvement in various multicellular behaviors. Despite this high interest, only very few studies have focused on the production of rhamnolipids by <it>Burkholderia </it>species.</p> <p>Results</p> <p>Orthologs of <it>rhlA</it>, <it>rhlB </it>and <it>rhlC</it>, which are responsible for the biosynthesis of rhamnolipids in <it>P. aeruginosa</it>, have been found in the non-infectious <it>Burkholderia thailandensis</it>, as well as in the genetically similar important pathogen <it>B. pseudomallei</it>. In contrast to <it>P. aeruginosa</it>, both <it>Burkholderia </it>species contain these three genes necessary for rhamnolipid production within a single gene cluster. Furthermore, two identical, paralogous copies of this gene cluster are found on the second chromosome of these bacteria. Both <it>Burkholderia </it>spp. produce rhamnolipids containing 3-hydroxy fatty acid moieties with longer side chains than those described for <it>P. aeruginosa</it>. Additionally, the rhamnolipids produced by <it>B. thailandensis </it>contain a much larger proportion of dirhamnolipids versus monorhamnolipids when compared to <it>P. aeruginosa</it>. The rhamnolipids produced by <it>B. thailandensis </it>reduce the surface tension of water to 42 mN/m while displaying a critical micelle concentration value of 225 mg/L. Separate mutations in both <it>rhlA </it>alleles, which are responsible for the synthesis of the rhamnolipid precursor 3-(3-hydroxyalkanoyloxy)alkanoic acid, prove that both copies of the <it>rhl </it>gene cluster are functional, but one contributes more to the total production than the other. Finally, a double Δ<it>rhlA </it>mutant that is completely devoid of rhamnolipid production is incapable of swarming motility, showing that both gene clusters contribute to this phenotype.</p> <p>Conclusions</p> <p>Collectively, these results add another <it>Burkholderia </it>species to the list of bacteria able to produce rhamnolipids and this, by the means of two identical functional gene clusters. Our results also demonstrate the very impressive tensio-active properties these long-chain rhamnolipids possess in comparison to the well-studied short-chain ones from <it>P. aeruginosa</it>.</p

    Pilot Testing Behavior Therapy for Chronic Tic Disorders in Neurology and Developmental Pediatrics Clinics

    Get PDF
    Comprehensive Behavioral Intervention for Tics (CBIT) is an efficacious treatment with limited regional availability. As neurology and pediatric clinics are often the first point of therapeutic contact for individuals with tics, the present study assessed preliminary treatment response, acceptability, and feasibility of an abbreviated version, modified for child neurology and developmental pediatrics clinics. Fourteen youth (9-17) with Tourette disorder across 2 child neurology clinics and one developmental pediatrics clinic participated in a small case series. Clinician-rated tic severity (Yale Global Tic Severity Scale) decreased from pre- to posttreatment, z = –2.0, P \u3c .05, r = –.48, as did tic-related impairment, z = –2.4, P \u3c .05, r = –.57. Five of the 9 completers (56%) were classified as treatment responders. Satisfaction ratings were high, and therapeutic alliance ratings were moderately high. Results provide guidance for refinement of this modified CBIT protocol

    Investigations Into Whole Water, Prototropic and Amide Proton Exchange in Lanthanide(III) DOTA-Tetraamide Chelates

    Get PDF
    Lanthanide(III) chelates of DOTA-tetraamide ligands have been an area of particular interest since the discovery that water exchange kinetics are dramatically affected by the switch from acetate to amide side-chain donors. More recently these chelates have attracted interest as potential PARACEST agents for use in MRI. In this paper we report the results of studies using chemical exchange saturation transfer (CEST) and some more recently reported chelates to re-examine the exchange processes in this class of chelate. We find that the conclusions of Parker and Aime are, for the most part, solid; water exchange is slow and a substantial amount of prototropic exchange occurs in aqueous solution. The extent of prototropic exchange increases as the pH increases above 8, leading to higher relaxivities at high pH. However, amide protons are found to contribute only a small amount to the relaxivity at high pH

    Identification of Burkholderia mallei and Burkholderia pseudomallei adhesins for human respiratory epithelial cells

    Get PDF
    <p>Abstract</p> <p>Background</p> <p><it>Burkholderia pseudomallei </it>and <it>Burkholderia mallei </it>cause the diseases melioidosis and glanders, respectively. A well-studied aspect of pathogenesis by these closely-related bacteria is their ability to invade and multiply within eukaryotic cells. In contrast, the means by which <it>B. pseudomallei </it>and <it>B. mallei </it>adhere to cells are poorly defined. The purpose of this study was to identify adherence factors expressed by these organisms.</p> <p>Results</p> <p>Comparative sequence analyses identified a gene product in the published genome of <it>B. mallei </it>strain ATCC23344 (locus # BMAA0649) that resembles the well-characterized <it>Yersinia enterocolitica </it>autotransporter adhesin YadA. The gene encoding this <it>B. mallei </it>protein, designated <it>boaA</it>, was expressed in <it>Escherichia coli </it>and shown to significantly increase adherence to human epithelial cell lines, specifically HEp2 (laryngeal cells) and A549 (type II pneumocytes), as well as to cultures of normal human bronchial epithelium (NHBE). Consistent with these findings, disruption of the <it>boaA </it>gene in <it>B. mallei </it>ATCC23344 reduced adherence to all three cell types by ~50%. The genomes of the <it>B. pseudomallei </it>strains K96243 and DD503 were also found to contain <it>boaA </it>and inactivation of the gene in DD503 considerably decreased binding to monolayers of HEp2 and A549 cells and to NHBE cultures.</p> <p>A second YadA-like gene product highly similar to BoaA (65% identity) was identified in the published genomic sequence of <it>B. pseudomallei </it>strain K96243 (locus # BPSL1705). The gene specifying this protein, termed <it>boaB</it>, appears to be <it>B. pseudomallei</it>-specific. Quantitative attachment assays demonstrated that recombinant <it>E. coli </it>expressing BoaB displayed greater binding to A549 pneumocytes, HEp2 cells and NHBE cultures. Moreover, a <it>boaB </it>mutant of <it>B. pseudomallei </it>DD503 showed decreased adherence to these respiratory cells. Additionally, a <it>B. pseudomallei </it>strain lacking expression of both <it>boaA </it>and <it>boaB </it>was impaired in its ability to thrive inside J774A.1 murine macrophages, suggesting a possible role for these proteins in survival within professional phagocytic cells.</p> <p>Conclusions</p> <p>The <it>boaA </it>and <it>boaB </it>genes specify adhesins that mediate adherence to epithelial cells of the human respiratory tract. The <it>boaA </it>gene product is shared by <it>B. pseudomallei </it>and <it>B. mallei </it>whereas BoaB appears to be a <it>B. pseudomallei</it>-specific adherence factor.</p

    Genetic Studies of Sulfadiazine-resistant and Methionine-requiring \u3cem\u3eNeisseria\u3c/em\u3e Isolated From Clinical Material

    Get PDF
    Deoxyribonucleate (DNA) preparations were extracted from Neisseria meningitidis (four isolates from spinal fluid and blood) and N. gonorrhoeae strains, all of which were resistant to sulfadiazine upon primary isolation. These DNA preparations, together with others from in vitro mutants of N. meningitidis and N. perflava, were examined in transformation tests by using as recipient a drug-susceptible strain of N. meningitidis (Ne 15 Sul-s Met+) which was able to grow in a methionine-free defined medium. The sulfadiazine resistance typical of each donor was introduced into the uniform constitution of this recipient. Production of p-aminobenzoic acid was not significantly altered thereby. Transformants elicited by DNA from the N. meningitidis clinical isolates were resistant to at least 200 μg of sulfadiazine/ml, and did not show a requirement for methionine (Sul-r Met+). DNA from six strains of N. gonorrhoeae, which were isolated during the period of therapeutic use of sulfonamides, conveyed lower degrees of resistance and, invariably, a concurrent methionine requirement (Sul-r/Met−). The requirement of these transformants, and that of in vitro mutants selected on sulfadiazine-agar, was satisfied by methionine, but not by vitamin B12, homocysteine, cystathionine, homoserine, or cysteine. Sul-r Met+ and Sul-r/Met− loci could coexist in the same genome, but were segregated during transformation. On the other hand, the dual Sul-r/Met− properties were not separated by recombination, but were eliminated together. DNA from various Sul-r/Met− clones tested against recipients having nonidentical Sul-r/Met− mutant sites yielded Sul-s Met+ transformants. The met locus involved is genetically complex, and will be a valuable tool for studies of genetic fine structure of members of Neisseria, and of genetic homology between species

    The Vehicle, 1961, Vol. 3 no. 2

    Get PDF
    Vol. 3, No. 2 Table of Contents The Voting CattleLinda Kay Campbellpage 5 But For the Passage of TimeDon Shepardsonpage 14 LoveJon Woodspage 16 Infinite JourneyJames E. Martinpage 19 The Clover ChainRichard W. Blairpage 20 SnowballSusan Daughertypage 24 Sureness Is NeverDon Shepardsonpage 26 ConceptionChristine McCollpage 34 Comedy: Relief and GriefTom McPeakpage 35 The Unspoken WordChristine McCollpage 35 CharmBenjamin Polkpage 36 Screaming SpiderTom McPeakpage 39 Just Once in an Early SpringE.J.B.page 39 HummingbirdPauline B. Smithpage 40 Willow TreesPauline B. Smithpage 40 MaturityChristine McCollpage 41 The New YearLinda Campbellpage 41 The StormMary-Jean Pitratpage 42 Ebony IvoryJean Danenbargerpage 42 The Fireball MailAllen Engelbrightpage 43 ExpectationChristine McCollpage 44 CatastropheChristine McCollpage 44 SophisticationBenjamin Polkpage 45 On Playing BridgeMyrna Jo Handleypage 46 SonnetMignon Stricklandpage 48https://thekeep.eiu.edu/vehicle/1009/thumbnail.jp

    The Vehicle, 1961, Vol. 3 no. 2

    Get PDF
    Vol. 3, No. 2 Table of Contents The Voting CattleLinda Kay Campbellpage 5 But For the Passage of TimeDon Shepardsonpage 14 LoveJon Woodspage 16 Infinite JourneyJames E. Martinpage 19 The Clover ChainRichard W. Blairpage 20 SnowballSusan Daughertypage 24 Sureness Is NeverDon Shepardsonpage 26 ConceptionChristine McCollpage 34 Comedy: Relief and GriefTom McPeakpage 35 The Unspoken WordChristine McCollpage 35 CharmBenjamin Polkpage 36 Screaming SpiderTom McPeakpage 39 Just Once in an Early SpringE.J.B.page 39 HummingbirdPauline B. Smithpage 40 Willow TreesPauline B. Smithpage 40 MaturityChristine McCollpage 41 The New YearLinda Campbellpage 41 The StormMary-Jean Pitratpage 42 Ebony IvoryJean Danenbargerpage 42 The Fireball MailAllen Engelbrightpage 43 ExpectationChristine McCollpage 44 CatastropheChristine McCollpage 44 SophisticationBenjamin Polkpage 45 On Playing BridgeMyrna Jo Handleypage 46 SonnetMignon Stricklandpage 48https://thekeep.eiu.edu/vehicle/1009/thumbnail.jp
    • …
    corecore