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In Rhizobium leguminosarum the ABC transporter responsible for rhamnose transport is dependent on RhaK, a sugar kinase that is necessary for the catabolism of rhamnose. It was hypothesized that RhaK has two separate functions; phosphorylation of rhamnose, and an unknown interaction with the rhamnose ABC transporter. To address this hypothesis a linker-scanning mutagenesis of rhaK was carried out. Two generated variants (RhaK72 and RhaK73) were found to maintain kinase activity, but were severely impaired in rhamnose transport function. Structural modelling suggested that both RhaK72 and RhaK73 affect surface exposed residues in two distinct regions localized to one face of the protein. This suggests that this proteins face may play a role in a protein-protein interaction that affects rhamnose transport. Using a two-hybrid system, an N-terminal and a C-teminal fragment of RhaK were both shown to interact with the N-terminal fragment of RhaT. These fragments span the regions that contain the rhaK73 and rhaK72 inserts respectively. When the rhaK72 and rhaK73 insert alleles were cloned and assayed using the two-hybrid system, these they were unable to interact with the RhaT fragment, suggesting these inserts abolish transport by interfering with a physical interaction between RhaT and RhaK. A phylogeny was generated based on the amino acid sequence of RhaK like proteins found in syntenous opereons. To gain insight into what residues may constitute a binding domain a PRALINE alignment of the orthologous kinases was combined with secondary structure analysis, known informative mutations, and functional residue predictions. A putative 12 amino acid binding site was identified using this method. An alanine scanning mutagenesis and subsequent two-hybrid analysis was carried out on this region. The substitution of any of these residues greatly affected the interaction between RhaT and RhaK. Although heterologous complementation of RhaK is possible, cosmid complementation anomalies and phylogenetic analysis of RhaK indicates the R. leguminosarum and S. meliloti kinases are different. Through a series of heterologous complementation experiments, enzyme assays, gene fusions, and transport experiments we show that the R. leguminosarum kinase is capable of directly phosphorylating rhamnose and rhamnulose, whereas the Sinorhizobium meliloti kinase does not have rhamnose kinase activity. / May 2015

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Göttingen, Univ., Diss., 2004. / Computerdatei im Fernzugriff.

Göttingen, Universiẗat, Diss., 2004.

Losing confidence in the ability to maintain balance can be more debilitating than a fall. Therefore, considering the importance of measuring balance confidence, the purpose of this study was to examine the validity and reliability of the ABC-6, a shortened version of the ABC-16, among diverse older adults. Participants were 251 diverse (72.1% African Americans, 62.5% low-income, 61% low-education) older adults (M age = 71.2 years, SD = 8.9). Participants volunteered for a falls risk screening which assessed multiple falls risk factors and balance confidence. The ABC-6 had excellent internal consistency reliability, substantial intraclass correlations, significant moderate to large correlations with physical activity, mobility, balance, and total falls risk, the ability to discriminate between fallers and nonfallers, and it was the only significant predictor of total falls risk. The ABC-6 was a valid and reliable measure of balance confidence and is a suitable measure for use among diverse older adults.

Despite improved availability of simple, relatively inexpensive, and highly effective antiretroviral treatment for HIV/AIDS, the disease remains a major public health challenge for women in sub-Saharan Africa (SSA). Given the numerous barriers in access to care for women in this region, every health issue that brings them into contact with the health system should be optimized as an opportunity to integrate HIV/AIDS prevention. Because most non-condom forms of modern contraception require a clinical appointment for use, contraception appointments could provide a confidential opportunity for access to HIV counseling, testing, and referral to care. This study sought to investigate the relationship between contraceptive methods and HIV testing among women in SSA. Data from the Demographic and Health Survey from four African countries-Congo, Mozambique, Nigeria, and Uganda-was used to examine whether modern (e.g., pills, condom) or traditional (e.g., periodic abstinence, withdrawal) forms of contraception were associated with uptake of HIV testing. Data for the current analyses were restricted to 35,748 women with complete information on the variables of interest. Chi-square tests and logistic regression models were used to assess the relationship between uptake of HIV testing and respondents' baseline characteristics and contraceptive methods. In the total sample and in Mozambique, women who used modern forms of contraception were more likely to be tested for HIV compared to those who did not use contraception. This positive association was not demonstrated in Congo, Nigeria, or Uganda. That many women who access modern contraception are not tested for HIV in high HIV burden areas highlights a missed opportunity to deliver an important intervention to promote maternal and child health. Given the increasing popularity of hormonal contraception methods in low-income countries, there is an urgent need to integrate HIV counseling, testing, and treatment into family planning programs. Women on hormonal contraceptives should be encouraged to continue to use condoms for HIV-prevention.

Aktivitetsbaserad kalkylering (ABC) är en kalkyleringsmetod som blev populärt under slutet av 80-talet och har sedan dess engagerat många forskare och praktiker. Konceptet växte allteftersom konsultbolag sålde implementeringar, mjukvara togs fram och vetenskapliga artiklar publicerades. Metoden kom dock att kritiseras för att vara komplex och resurskrävande och det skapades en bild av att det endast var stora företag som var lämpade att använda sig av metoden. På senare tid har studier gjorts som visat att mindre företag framgångsrikt kunnat implementera och använda sig av ABC och rekommendationer och riktlinjer för dessa har tagits fram. Vi finner dock en avsaknad på studier riktade mot mikroföretags tillämpande av ABC. Därför anser vi det av vikt att undersöka och presentera hur en sådan modell skulle kunna utformas samt vilka problem respektive möjligheter som skulle kunna uppstå för mikroföretag i en sådan process. För att fylla detta teoretiska och praktiska gap har vi valt att implementera en modell för ABC-kalkylering i ett mikroföretag. Vår studie har således utformats som en aktionsstudie på fallföretaget Micro AB med säte i Umeå. För att på ett tillfredställande sätt kunna utföra studien har kvalitativ och kvantitativ metod använts inför insamling och bearbetning av data. Genom implementeringen har vi kunnat identifiera såväl problem som möjligheter och en modell har kunnat utformas för implementering av ABC i mikroföretag. Tidigare belysta problem inom litteraturen som spårning av indirekta kostnader och beräkning av företagets praktiska kapacitet har kunnat identifieras. Vidare har problem kunnat identifieras med bearbetningen av företagets redovisningsdata, något vi anser fått för lite utrymme i rådande litteratur. Vår studie har även funnit att faktorer som ledningens insyn och företagets dokumentation skapat möjligheter så som genomförandet av en effektiv aktivitetsanalys, utförandet av kvalificerade estimeringar och framtagandet av relevanta kostnadsdrivare. En god access till Micro AB:s informationskällor har också identifierats som en stor möjlighet för implementeringens genomförande. Studien har resulterat i praktiska rekommendationer för implementering av en ABC modell för mikroföretag samt förslag för vidare forskning där fokus legat på att öka kvantiteten av studier rörande ABC i mikroföretag. Här lyfts förslag på framtida studier så som en kartläggning av mikroföretags förmåga att utföra kvalificerade estimeringar som led i implementeringsprocessen. Vi lämnar också förslag på studier rörande den bearbetningsproblematik vi stött på under vår implementering. En modell med tillhörande rapportverktyg och rekommendationer för dess användande har tagits fram till Micro AB där dem genom den utformade ABC-modellen kan identifiera lönsamheten för enskilda kunder.

Campylobacter jejuni is a human pathogen that causes severe diarrhea! disease. However, our understanding of C. jejuni virulence mechanisms and survival during disease and transmission remains limited. Amino acid ATP Binding Cassette (AA-ABC) transporters in C. jejuni have been proposed as being important for bacterial physiology and pathogenesis. We have investigated a novel AA-ABC transporter system, encoded by cj0467-9, by generating targeted deletions of cj0467 (membrane transport component) and cj0469 (ATPase component) in C. jejuni 81-176. Analyses described herein have led us to designate these genes paqP and paqQ, respectively [pathogenesis-ssociated glutamine (q) ABC transporter permease () and ATPase (Q)]. We found that loss of either component resulted in amino acid uptake defects, most notably diminished glutamine uptake. Both ΔpaqP and ΔpaqQ mutants also exhibited a surprising but significant increase in short-term intracellular survival in macrophages and epithelial cells. Levels of resistance to a series of environmental and in vivo stresses were examined. Both mutants were hyper-resistant to aerobic and oxidative stress, and while ΔpaqP was also hyper-resistant to heat and osmotic shock, ΔpaqQ was more susceptible than wild-type to the latter two stresses. Annexin-V staining coupled with fluorescence microscopy revealed that macrophages infected with the ΔpaqP and ΔpaqQ mutants underwent a lower level of apoptosis than cells infected with wild-type bacteria. Macrophages infected with the mutant strains exhibited a transient decrease in ERK activation compared to wild type-infected macrophages, potentially explaining the reduced apoptosis phenotype. The ΔpaqP mutant did not exhibit a defect for short or longer term mouse colonization, consistent with its increased stress survival and diminished host cell damage phenotypes. Collectively, these results demonstrate a unique correlation between an AA-ABC transporter with bacterial stress tolerance, intracellular survival, host cell damage, and host signal transduction in response to pathogen infection.