|
|
|
|
|
|
Cloning and Analysis of the Telomere and Terminal Inverted Repeat of the Linear Chromosome of Streptomyces griseus. Kohei Goshi, 2002.Cloning and sequencing of the telomere of Streptomyces griseus revealed five palindromic sequences in the terminal 116 nucleotides, all of which can make a hairpin loop structure . However, the end sequence cannot form the foldback secondary structure that is common in Streptomyces telomeres and is suggested to be necessary for terminal replication . Both inside ends of the terminal inverted repeat (TIR) were also cloned and sequenced . The results confirmed the size of the TIR to be 24 kb and identified two almost identical open reading frames that might have been involved in the formation of the TIR . Poly-ß-Hydroxybutyrate Biosynthesis in the Facultative Methylotroph Methylobacterium extorquens AM1: Identification and Mutation of gap11, gap20, and phaR. Natalia Korotkova, 2002.Methylobacterium extorquens AM1, a serine cycle facultative methylotroph, accumulates poly-ß-hydroxybutyrate (PHB) as a carbon and energy reserve material during growth on both multicarbon- and single-carbon substrates . Recently, the identification and mutation of the genes involved in the biosynthesis and degradation of PHB have been described for this bacterium, demonstrating that two of the genes of the PHB cycle (phaA and phaB) are also involved in C1 and C2 metabolism, as part of a novel pathway for glyoxylate regeneration in the serine cycle (N . Korotkova and M . E . Lidstrom, J . Bacteriol . 183:1038-1046, 2001; N . Korotkova, L . Chistoserdova, V . Kuksa, and M . E . Lidstrom, J . Bacteriol . 184:1750-1758, 2002) . In this work, three new genes involved in PHB biosynthesis in this bacterium have been investigated via mutation and phenotypic analysis: gap11, gap20, and phaR . We demonstrate that gap11 and gap20 encode two major granule-associated proteins (phasins) and that mutants with mutations in these genes are defective in PHB production and also in growth on C2 compounds, while they show wild-type growth characteristics on C1 or multicarbon compounds . The phaR mutant shows defects in both PHB accumulation and growth characteristics when grown on C1 compounds and has defects in PHB accumulation but grows normally on C3 and C4 compounds, while both PHB accumulation and growth rate are at wild-type levels during growth on C2 compounds . Our results suggest that this phenotype is due to altered fluxes of acetyl coenzyme A (CoA), a major intermediate in C1, C2, and heterotrophic metabolism in M . extorquens AM1, as well as the entry metabolite for the PHB cycle . Therefore, it seems likely that PhaR acts to control acetyl-CoA flux to PHB in this methylotrophic bacterium . Development and Application of a Monoclonal-Antibody Technique for Counting Aureococcus anophagefferens, an Alga Causing Recurrent Brown Tides in the Mid-Atlantic United States. David A. Caron, 2003.A method was developed for the rapid detection and enumeration of Aureococcus anophagefferens, the cause of harmful algal blooms called "brown tides" in estuaries of the Mid-Atlantic United States . The method employs a monoclonal antibody (MAb) and a colorimetric, enzyme-linked immunosorbent assay format . The MAb obtained exhibits high reactivity with A. anophagefferens and very low cross-reactivities with a phylogenetically diverse array of other protists and bacteria . Standard curves are constructed for each 96-well microtiter plate by using known amounts of a preserved culture of A . anophagefferens . This approach allows estimation of the abundance of the alga in natural samples . The MAb method was compared to an existing method that employs polyclonal antibodies and epifluorescence microscopy and to direct microscopic counts of A . anophagefferens in samples with high abundances of the alga . The MAb method provided increased quantitative accuracy and greatly reduced sample processing time . A spatial survey of several Long Island estuaries in May 2000 using this new approach documented a range of abundances of A . anophagefferens in these bays spanning nearly 3 orders of magnitude .
|
© 2005
Transgalactic Ltd (manufacturer of Bioscreen C software) |
Privacy Statement | P.O. Box
1393, 00101 Helsinki, Finland,
Last modified: May 25, 2005
| ||||||
