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Biomedical subjects

R Garesse

Publications and source records attributed to R Garesse.

40 records · Page 3Linked to original sources
PubMed1988

Drosophila melanogaster mitochondrial DNA: gene organization and evolutionary considerations.

The sequence of a 8351-nucleotide mitochondrial DNA (mtDNA) fragment has been obtained extending the knowledge of the Drosophila melanogaster mitochondrial genome to 90% of its coding region. The sequence encodes seven polypeptides, 12 tRNAs and the 3' end of the 16S rRNA and CO III genes. The gene organization is strictly conserved with respect to the Drosophila yakuba mitochondrial genome, and different from that found in mammals and Xenopus. The high A + T content of D. melanogaster mitochondrial DNA is reflected in a reiterative codon usage, with more than 90% of the codons ending in T or A, G + C rich codons being practically absent. The average level of homology between the D. melanogaster and D. yakuba sequences is very high (roughly 94%), although insertion and deletions have been detected in protein, tRNA and large ribosomal genes. The analysis of nucleotide changes reveals a similar frequency for transitions and transversions, and reflects a strong bias against G + C on both strands. The predominant type of transition is strand specific.

Amino Acid Sequence↗
PubMed1980

The unmasking of proteolytic activity during the early development of Artemia salina. Identification of a precursor after hatching.

The proteolytic activities of Artemia salina immediately after hatching are found masked in a precursor of high molecular weight (approximately 100000). The molecular weight of this precursor decreases slightly as development proceeds. However, its kinetic and chromatographic properties vary greatly. Shortly after hatching, the activities are highly inhibited, can be activated severalfold by the chaotropic agent potassium iodide and are not proportional to the amount of enzyme-containing extract added. Later after hatching, its kinetics become normal. From these observations we have concluded that (a) the majority, if not all, of the proteinase activities found later in development are already present immediately after hatching, although in an inhibited state that is gradually activated; (b) the proteinases are not found free in the cytoplasm but in a complex which may allow regulation of their activity.

Animals↗
PubMed1979

A fluorescamine-based sensitive method for the assay of proteinases, capable of detecting the initial cleavage steps of a protein.

The properties of the reaction of fluorescamine with proteins are the basis for the development of a sensitive, general and simple method for the assay of proteolytic activities. More importantly, the assay measures the initial step(s) of proteolytic attack, making it specially suitable for the examination of the controlling factors that regulate proteolytic degradation and/or the detection of 'specific' proteinases. The method allows the simple determination of the general parameters of enzyme action, V and Km, using proteins, i.e. the physiological substrates of the proteinases. The more appropriate proteins to be used as substrates are the N-amino-terminally blocked ones. Many proteins fulfill this requirement. If the particular protein whose degradation has to be studied lacks this modification, three different approaches can be used to study its degradation: (a) the accumulation of N-amino termini in excess over that of the intact substrate; (b) a gel filtration/continuous method and (c) the chemical blockage of its amino groups. The particular advantages of each of these approaches are discussed.

Endopeptidases↗