Search results for "Biosynthesi"
showing 10 items of 526 documents
Cyclosporin A mediates immunosuppression of primary cytotoxic T cell responses by impairing the release of interleukin 1 and interleukin 2
1981
The site of action of the immunosuppressive drug cyclosporin A in in vitro cytotoxic allograft responses has been localized. General cytotoxic effects of the drug on proliferating T cells became apparent at concentrations of 500-1000 ng/ml, while selective effects were observed at concentrations of 10-100 ng/ml. The selective effects included a blockade of interleukin 2 release from activated T helper cells on the one hand and inhibition of interleukin 1 release from splenic adherent cells on the other. While cyclosporin A did not interfere with the intracellular events required for the activation and subsequent clonal expansion of alloreactive T cells, the lack of interleukin 1 and interle…
A breakdown in macromolecular synthesis preceding differentiation in Streptomyces coelicolor A3(2)
1990
Summary: A transitory cessation of growth was recorded in Streptomyces coelicolor A3(2) at the end of vegetative mycelium formation on solid medium. In the same phase a striking reduction in protein and nucleic acid synthesis was detected. Growth and macromolecular synthesis resumed, nearly reaching the original values, when morphological differentiation occurred. It is concluded that a physiological stress occurs within the bacterial population just before the onset of the morphological differentiation.
Effect of Ultraviolet Irradiation on Biosynthesis of Dna in Guinea-Pig Skin in Vivo
1974
The molecular and metabolic alterations preceding the clinical manifestation of a photobiologic process, the erythematous or sunburn reaction, were investigated in mammalian skin in vivo. The effect of a moderate (2.5–3 times the minimal erythema dose [MED]) and a large (6–8 times MED) dose of ultraviolet radiation (290–320 nm) on the incorporation of [ Me - 3 H]-thymidine into epidermal cell DNA of guinea pigs was studied. The epilated half of the back of each animal was irradiated with various doses of ultraviolet light, and the other half served as the nonirradiated control. The amount of intraperitoneally injected [ Me - 3 H]-thymidine incorporated into the DNA was determined by the iso…
Caseicin, a bacteriocin from Lactobacillus casei.
1993
The intracellular bacteriocin caseicin 80 was purified from cell extracts of Lactobacillus casei strain B80. It is a thermolabile protein with an apparent molar mass of 42 kDa. As no plasmids were observed in the bacteriocinogenic strain it is assumed that caseicin is encoded by the bacterial chromosome. Using 14C-labelled precursors it was found that biosynthesis of DNA and proteins was influenced by caseicin but this inhibition is probably not the primary effect. The incorporation of fructose but not of glucose into cellular material was inhibited by caseicin.
Cloning and sequencing of the dnaK region of Streptomyces coelicolor A3(2)
1993
Abstract The dnaK homologue of Streptomyces coelicolor A3(2) strain M145 has been cloned and sequenced. Nucleotide sequence analysis of a 2.5-kb region revealed an open reading frame (ORF) encoding a predicted DnaK protein of 618 amino acids (Mr = 66 274). The dnaK coding sequence displays extreme codon bias and shows a strong preference for CGY and GGY, for Arg and Gly codons, respectively. The predicted DnaK sequence has a high Lys:Arg ratio which is not typical of streptomycete proteins. The region immediately downstream from dnaK contains an ORF for a GrpE-like protein; the predicted start codon of grpE overlaps the last two codons of dnaK, indicating that the two genes are translationa…
Prephenate dehydratase from the aphid endosymbiont (Buchnera) displays changes in the regulatory domain that suggest its desensitization to inhibitio…
2000
ABSTRACT Buchnera aphidicola , the prokaryotic endosymbiont of aphids, complements dietary deficiencies with the synthesis and provision of several essential amino acids. We have cloned and sequenced a region of the genome of B. aphidicola isolated from Acyrthosiphon pisum which includes the two-domain aroQ/pheA gene. This gene encodes the bifunctional chorismate mutase-prephenate dehydratase protein, which plays a central role in l -phenylalanine biosynthesis. Two changes involved in the overproduction of this amino acid have been detected. First, the absence of an attenuator region suggests a constitutive expression of this gene. Second, the regulatory domain of the Buchnera prephenate de…
Molecular characterization of the leucine cluster in Buchnera PSY, primary endosymbiont of the aphid Pemphigus spyrothecae
2002
ABSTRACT Buchnera strains from most aphid subfamilies studied to date have been found to carry the leucine gene cluster ( leuA , - B , - C , and - D ) on a plasmid, an organization unique among bacteria. Here, however, we demonstrate a classical chromosomal location of the cluster in Buchnera sp. strain PSY from the aphid Pemphigus spyrothecae (subfamily Pemphiginae). The genes that flank leuABCD in Buchnera sp. strain PSY appear to be adjacent in the genome of Buchnera sp. strain APS, a strain carrying a leucine plasmid. We propose that the presence of a leucine plasmid predates the diversification of symbiotic Buchnera and that the chromosomal location observed in Buchnera sp. strain PSY …
The glycosyltransferase activities of lysyl hydroxylase 3 (LH3) in the extracellular space are important for cell growth and viability.
2008
Abstract Lysyl hydroxylase (LH) isoform 3 is a post-translational enzyme possessing LH, collagen galactosyltransferase (GT) and glucosyltransferase (GGT) activities. We have demonstrated that LH3 is found not only intracellularly, but also on the cell surface and in the extracellular space, suggesting additional functions for LH3. Here we show that the targeted disruption of LH3 by siRNA causes a marked reduction of both glycosyltransferase activities, and the overexpression of LH3 in HT-1080 cells increases hydroxylation of lysyl residues and the subsequent galactosylation and glucosylation of hydroxylysyl residues. These data confirm the multi-functionality of LH3 in cells. Furthermore, t…
Analysis of expression of an alternative La (SS-B) cDNA and localization of the encoded N- and C-terminal peptides
1997
AbstractA deletion of an (A)-residue was detected in a cDNA encoding for the nuclear autoantigen La/SS-B. The cDNA was recently isolated from a cDNA library made from peripheral blood lymphocytes of a patient with primary Sjögren's Syndrome. The region, where the deletion occurred, represents a hot spot region in the La gene(s). It leads to a frame shift mutation and a premature stop codon eleven amino acids downstream of the deletion site within one of the protease sensitive regions of the La protein. In spite of the frame shift mutation expression of full length La protein occurred efficiently in E. coli. Full length La protein was also made in SF9 cells infected with recombinant baculovi…
Rat adrenoleukodystrophy-related (ALDR) gene: full-length cDNA sequence and new insight in expression.
2001
X-linked adrenoleukodystrophy (X-ALD) is an inherited demyelinating disorder due to mutations in the ALD gene, which encodes a peroxisomal ABC half-transporter (ALDP). It has been suggested that ALDP assembles with ALDRP (adrenoleukodystrophy-related protein), a close homologous half-transporter, to form a functional heterodimer. For the first time full-length ALDRP cDNA (5.5 kb) was cloned, and 5' and 3' RACE analysis revealed that alternative usage of polyadenylation sites generates the two transcripts of 3.0 and 5.5 kb observed in the rat in Northern blot analysis. Southern blotting and chromosomal mapping demonstrated one ALDR locus in the rat genome. Characterisation of the 3' flanking…