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M Goyffon

Publications and source records attributed to M Goyffon.

At least 37 records · Page 2Linked to original sources
PubMed1996

Characterization of novel cysteine-rich antimicrobial peptides from scorpion blood.

We have isolated, from the hemolymph of unchallenged scorpions of the species Androctonus australis, three distinct antimicrobial peptides, which we have fully characterized by Edman degradation, electrospray ionization mass spectrometry, and matrix-assisted laser desorption/ionization mass spectrometry. Two are novel molecules: (i) androctonin, a 25-residue peptide with two disulfide bridges, active against both bacteria (Gram-positive and Gram-negative) and fungi and showing marked sequence homology to tachyplesins and polyphemusins from horseshoe crabs; and (ii) buthinin, a 34-residue antibacterial (Gram-positive and Gram-negative) peptide with three disulfide bridges. The third peptide contains 37 residues and three disulfide bridges and clearly belongs to the family of anti-Gram-positive insect defensins. We have synthesized androctonin and explored its activity spectrum and mode of action.

Amino Acid Sequence↗
PubMed1995

[PCR: principles and prospects in clinical biology].

In the short time it has been available, the Polymerase Chain Reaction (PCR) has been rapidly established as a powerful tool for the analysis of genes leading to a wide spread of its application in research. Its basic qualities (sensitivity, specificity and quickness) also offer facilities for its application to the detection and amplification of foreign and aberrant genes. Recent reports have already shown its ability to detect microorganisms and to identify genes related to molecular diseases. Therefore, its application to the diagnosis of infectious and genetic diseases is expected in the next future. However, some problems have to be solved before the use of this technology is routine in clinical chemistry.

Chemistry, Clinical↗
PubMed1994

[Latrodectism in Madagascar].

Data concerning lactrodectism in Madagascar is scarce. Two spider species of the Latrodectus genus are found on the Grand Isle: the black widow Latrodectus mactans mena vody and the brown widow Latrodectus geometricus. From March 1991 through July 1992, 10 cases of envenomation by these spiders were treated in the Intensive Care Unit of Antananarivo Hospital. Symptomatology was remarkable with regard to severity (one fatality due to cardiovascular failure, one gangrene of the foot) as well as clinical manifestations (immediate local pain, kidney dysfunction, arterial hypertension). In two cases, the spider was captured and identified. Both were female brown widows (Latrodectus geometricus), which might explain the differences observed in comparison with the classic features of latrodectism that have been established from American and European black widow bites. Since antivenom was unavailable, only symptomatic treatment was administered, including intravenous calcium that proved effective for pain relief.

Adult↗
PubMed1994

[Facts on venomous animals].

Research into venoms have been extensively developed during the last years, and some groups of venomous animals seldom studied have been recently the subject of new important results, such as the Cones (Gasteropodes, Molluscs) and Spiders, in the venom of which new types of neurotoxic molecules have been described. Concerning the most studied groups, new toxic molecules have been identified in snake (Dendroaspis sp., Atractaspis sp.) and scorpion venoms. The scorpion venoms contain a large variety of toxins acting on various ionic channels, Na+, K+, Ca++ or Cl-. Many structural relations between venomous toxins (Cones and Najas) or between toxins and physiological molecules (sarafotoxins and endothelins, scorpion toxins and Arthropod defensins) have been described and raise important phylogenetic problems which might be also the starting point of new domains of applied research.

Animals↗
PubMed1993

Purification and characterization of a scorpion defensin, a 4kDa antibacterial peptide presenting structural similarities with insect defensins and scorpion toxins.

Insect defensins are a group of inducible small-sized antibacterial peptides with three intramolecular disulfide bridges. NMR studies have recently shown that they share striking structural similarities with scorpion toxins. We have investigated in a scorpion species, Leiurus quinquestriatus, the potential presence of antibacterial molecules and report the isolation and structural characterization of a novel insect defensin homologue, which we refer to as scorpion defensin. This peptide shows a remarkably high degree of sequence homology with a defensin recently characterized in a species belonging to the ancient insect order of the Odonata with which it defines a novel ancient subclass of defensins. The scorpion defensin has in common with the scorpion toxins a consensus sequence Cys-[...]-Cys-Xaa-Xaa-Xaa-Cys-[...]-Gly-Xaa-Cys-[...]-Cys-Xaa-Cys present in all scorpion toxins characterized so far.

Amino Acid Sequence↗
PubMed1991

[Antivenom serotherapy: its applications, its limitations, its future].

A hundred years after its discovery, authors review the antivenom therapy. Antivenom manufacture is described and antivenom therapy methods are presented. Indication of antivenom should be reserved to those who are really envenomed. Delay from the bite should not discredit antivenom therapy. Quantity of antivenom should depend on snake species, clinical features and evolution after treatment. Intravenous injections of antivenom should be strongly recommended as the most efficient. The future of antivenom therapy is emphasized.

Animals↗
PubMed1990

Antioxidant activity of hemocyanin; a pulse radiolysis study.

In order to determine the reactivity on hemocyanin from Androctonus australis, the reaction of superoxide anion has been investigated using pulse radiolysis. The kinetics of O2- decays have been studied in aqueous buffered media at various basic pH (8, 8.5 and 9), first in the absence and then in the presence of hemocyanin (in oxygenated solutions containing formate anion 0.16 mol.l-1). We have shown that, in the presence of hemocyanin, O2- decay is a first-order process whose apparent rate constant is proportional to protein concentration (10(-7) to 10(-6) mol.l-1) and pH independent between 8 to 9. A second-order rate constant of 3.5 +/- 0.1.10(7) mol-1.l.s-1, has been deduced for the catalytic rate constant of hemocyanin with O2-. Meanwhile, this activity is smaller than that described for free copper, eukaryotic Cu-Zn-SOD or some copper chelates. We have verified that apohemocyanin--the copper deprived protein--does not exhibit such an activity vs. SOD (superoxide dismutase).

Animals↗
PubMed1987

Pyridoxylated polymerized hemoglobin solution processing. Interest of a membrane molecular fractionation step.

Glutaraldehyde hemoglobin polymerization gives too many high polymers, resulting in a too viscous solution. We describe here an alternate method leading to superior results, as compared to the classical one. This method includes a molecular fractionation step using a tangential flow ultrafiltration that secondarily lowers the unpolymerized tetramer's content of a mildly polymerized, pyridoxylated hemoglobin solution (Pyr-Poly Hb). This leads to an adequately polymerized product with a lesser high polymer content, implying a lower viscosity. We thus obtain a pyridoxylated, polymerized molecular fractionated solution presenting suitable features as a blood substitute: A 7.5 g% hemoglobin 2 g% albumin solution had a 16% unpolymerized tetramer's ratio, a 1.8 mPas viscosity, a P50 of 2.8 kPa, a Hill coefficient of 2.1, a binding coefficient of 1.3 mL/g, a colloid osmotic pressure of 2.4 kPa, and a methemoglobin concentration of 3% Male-Sprague-Dawley rats undergoing an isovolumic blood exchange with this Pyr-Poly Hb solution, down to a 2% hematocrit, present a mean survival time of 20 h.

Animals↗
PubMed1983

Cytophysiological aspects of digestion and storage in the liver of a scorpion, Androctonus australis (Arachnida).

The liver of a scorpion, Androctonus australis (Arachnida), was examined electron-microscopically and cytochemically, emphasizing correlations between structure, cytochemistry and physiology. The liver consists of digestive diverticula and interstitial tissue. Digestive diverticula are composed of basophilic cells and digestive cells. Basophilic cells produce exoenzymes. Digestive cells ensure intracellular digestion of nutrients absorbed by pinocytosis and store glycogen, lipids and mineral salts; the wastes of the digestive process (guanine, uric acid, mineral elements, pigments) are concentrated in "brown body vacuoles" which are ejected into the lumen of the diverticula. The interstitial tissue stores glycogen and lipids; it contains many lysosome-like organelles rich in iron. Fasting induces a decrease of the ratio of the volume of the diverticula to that of the interstitial tissue, a slow disappearance of the reserves in both diverticula and interstitial tissue, an increase of synthesis in the basophilic cells, and a decrease of the number of vacuoles in the digestive cells. The digestive mode of the scorpions associates a primitive intracellular process with an advanced extracellular process. The interstitial tissue can be considered as homologous to the adipose tissue of insects and myriapods, although it is devoid of urate cells. The excretion of guanine and uric acid has a peculiar meaning, because these purine wastes do not come from endogenous catabolism.

Animals↗
PubMed1983

Producers of antivenom sera.

A list of the producers of antivenom sera in presented along with a listing of the venomous species against which the antivenin is prepared. Some characteristics of the antivenins are specified, such as polyvalence or monovalence, animal source, etc.

Africa↗
PubMed1982

Epidemiological and clinical characteristics of the scorpion envenomation in Tunisia.

This work deals with a clinical and epidemiological study of the scorpion envenomation in Tunisia, from 717 scorpion stings recorded during a year at the Sfax Hospital with a mortality rate of 0.35%, all the patients died being less 15 years old. The serotherapy with a specific antivenin made in the Institut Pasteur of Tunis is the main element of the therapeutics.

Adolescent↗
PubMed1976

[Spectroscopic study of the structural changes of scorpion hemocyanin, induced by pH variations and addition of various salts].

Structural modifications of the scorpion haemocyanin induced by pH variations and salt addition are studied by U.V. absorption, fluorescence, circular dichroism and light scattering. Haemocyanin fluorescence is due to both aromatic amino-acids tyrosine and tryptophan. Deoxygenation or denaturation lead to a fourfold enhancement of its intensity. At acidic pH the active site is modified and the protein is dissociated, but at alkaline pH the haemocyanin aggregates. The addition of different salts (sodium citrate, potassium bromide and iodide...) involves protein dissociation, the amplitude of which depends on the anion. But pH variations and salt addition don't change the haemocyanin secondary structure as shown by circular dichroism. The C.D. spectrum of scorpion haemocyanin exhibits the characteristic bands of Arthropod haemocyanine.

Animals↗