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Lack of Effect of Recombinant Human Growth Hormone on the In Vitro Activities of Antiretroviral Drugs against Human Immunodeficiency Virus Type 1. Mark A Wainberg, 2004.We studied the effects of recombinant human growth hormone (r-hGH) on human immunodeficiency virus type 1 replication by growing both wild-type and drug-resistant variants of virus in the presence of various concentrations of eight different antiretroviral drugs . r-hGH had no significant effect on either viral replication or the 50% inhibitory concentrations of these compounds . Transformation of Folate-Consuming Lactobacillus gasseri into a Folate Producer. Arno Wegkamp, 2004.Five genes essential for folate biosynthesis in Lactococcus lactis were cloned on a broad-host-range lactococcal vector and were transferred to the folate auxotroph Lactobacillus gasseri . As a result L . gasseri changed from a folate consumer to a folate producer . This principle can be used to increase folate levels in many fermented food products . The Ralstonia eutropha PhaR Protein Couples Synthesis of the PhaP Phasin to the Presence of Polyhydroxybutyrate in Cells and Promotes Polyhydroxybutyrate Production. Gregory M. York, 2002.Polyhydroxyalkanoates (PHAs) are polyoxoesters that are produced by many bacteria and that accumulate as intracellular granules . Phasins (PhaP) are proteins that accumulate during PHA synthesis, bind PHA granules, and promote further PHA synthesis . Interestingly, PhaP accumulation seems to be strictly dependent on PHA synthesis, which is catalyzed by the PhaC PHA synthase . Here we have tested the effect of the Ralstonia eutropha PhaR protein on the regulation of PhaP accumulation . R . eutropha strains with phaR, phaC, and/or phaP deletions were constructed, and PhaP accumulation was measured by immunoblotting . The wild-type strain accumulated PhaP in a manner dependent on PHA production, and the phaC deletion strain accumulated no PhaP, as expected . In contrast, both the phaR and the phaR phaC deletion strains accumulated PhaP to higher levels than did the wild type . This result implies that PhaR is a negative regulator of PhaP accumulation and that PhaR specifically prevents PhaP from accumulating in cells that are not producing PHA . Transfer of the R . eutropha phaR, phaP, and PHA biosynthesis (phaCAB) genes into a heterologous system, Escherichia coli, was sufficient to reconstitute the PhaR/PhaP regulatory system, implying that PhaR both regulates PhaP accumulation and responds to PHA directly . Deletion of phaR caused a decrease in PHA yields, and a phaR phaP deletion strain exhibited a more severe PHA defect than a phaP deletion strain, implying that PhaR promotes PHA production and does this at least partially through a PhaP-independent pathway . Models for regulatory roles of PhaR in regulating PhaP and promoting PHA production are presented . Structural and Functional Analysis of a Putative Gene Cluster for Palatinose Transport on the Linear Chromosome of Agrobacterium tumefaciens MAFF301001. Devika M. De Costa, 2003.We identified a putative pal gene cluster (palR, palE, palF, palG, palK, palA, and palB) in the plant-tumorigenic bacterium Agrobacterium tumefaciens MAFF301001; by sequencing analyses, this cluster was found to be involved in palatinose transport, and its functional importance was revealed by mutational analyses . The pal gene products were highly homologous to those of putative trehalose/maltose ABC-type transport systems but were not essential to bacterial growth on trehalose . Insertion mutations in the palK and palE genes showed the necessity of these genes for bacterial growth and chemotaxis with palatinose as the carbon source, but no inhibition of tumorigenesis was observed . Growth on trehalose and maltose was not influenced by the mutations .
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