Characterization of the amino acids of bovine fibrinogen involved in the fibrinogen-thrombin interaction of the blood clotting process. Comparison with the milk clotting process

Summary Bovine fibrinogen and the A and B chains of bovine fibrinogen have been subjected to chemical modification by a number of reagents and the effects of these procedures on the susceptibility of the proteins to thrombin hydrolysis is described. The reagents used were rose bengal (for photo-oxidation), 2-hydroxy-5-nitrobenzyl bromide, N-acetylimidazole, iodoacetic acid and diethyl pyrocarbonate. Evidence is presented which indicates that the tryptophan and tyrosine residues of fibrinogen are not involved to any great extent in the interaction of this protein with thrombin. Modification with iodoacetic acid suggests that methionine residues play a major role in such interactions, but the fibrinogen chains on which the important residues reside remain uncertain. The use of diethyl pyrocarbonate indicates the participation also of histidine in fibrinogen-thrombin interactions and that, whereas the histidine residues of the B chain are involved to a great extent, it appears that those of the Aa chain are not. The similarities which exist between the fibrinogen-thrombin and the -casein-chymosin systems are discussed.Abbreviations used DEP diethyl pyrocarbonate (ethoxyformic anhydride) - HNBB 2-hydroxy-5-nitrobenzyl bromide - N-Acl N-acetylimidazole - PTC phenylthiocarbamyl - PTH 3-phenyl-2-thiohydantoin.     

Congenital defects of the upper lateral incisors (ULI): Condition and measurements of the other teeth,measurements of the superior arch,head and face

We surveyed a French male population for the incidence of missing or reduced upper lateral incisors (ULI). In 5,738 subjects, we observed an incidence of 1.59% with one or two reduced ULI (the other normal) and 1.90% with one or two missing ULI (the other normal or reduced), altogether, 3.49% affected subjects. Furthermore, 250 random controls were observed. Agenesis of other teeth is more frequent in propositi. Missing third molars were 12.4% in controls, 24.0% in propositi with reduced ULI and 39.6% in propositi with two missing ULI. Furthermore, agenesis of incisors, canines and premolars ranges from 0.4% in controls to 1.3% in propositi having reduced ULI and 5.0% in propositi with two missing ULI. So, propositi with reduced ULI are intermediate between the controls and the propositi with missing ULI with respect to the frequency of agenesis of other teeth. On the other hand, a different ranking is observed with respect to the teeth measurements: reduction of tooth size is more marked in propositi with reduced ULI than in propositi with missing ULI. The reduction mainly affects canines, incisors and to a lesser degree, premolars. Arch length and interpremolar diameters are smaller in propositi with missing ULI, compared with controls.     

Contribution to the structural characterization of eucaryotic PSI reaction centre—I. Critical analysis of the polypeptidic composition of different P700 enriched fractions

In thylakoid membranes, several peptides of high MW are present which may interfere with the study of CP1's components. Modifying Cleveland's technique [7] for limited proteolysis, we have characterized the polypeptides found in the 60 kD region. Some may result from incomplete washing of the CF1 while others come from the CP1; indeed, this chlorophyll protein complex, which has a higher MW (above 100 kD), very often undergoes a dissociation into smaller components of about 60 KD MW.Analysis of the protein content of different preparations commonly used to obtain PSI reaction centre enriched fractions has been performed. The and subunits of CF1 are among the main contaminants of most of these preparations. A further purification step is described which can be applied to all these preparations, but numerous peptides are still present in the active fractions. It is most unlikely that all these polypeptides are required for the primary photochemical event, and this emphasizes the necessity to find a new simple method to purify PSI reaction centres.     

Sialyl-transferase mitochondriale

A sialyl transferase activity is found in purified mitochondria. It is not due to residual contamination and this enzymatic system is located in the outer mitochondrial membrane. This proves mitochondrial autonomy in regard to glycoconjugate sialylation.     

Electron microscopic study of the mandibular glands of Kalotermes flavicollis Fabr. (Isoptera; Calotermitidae)

Summary The mandibular glands of Kalotermes were examined in different castes. They showed sexual dimorphism in the soldiers and primary reproductives. Moreover, in female soldiers and queens, mandibular gland cells contained numerous crystalline structures of mitochondrial origin. The role of these glands (secretion of saliva or pheromone) is discussed.

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Résumé Les glandes mandibulaires de Calotermes sont étudiées dans les différentes castes. Elles présentent un dimorphisme sexuel chez les soldats et les sexués. Après la mue imaginale, les cellules glandulaires ont toujours une activité sécrétrice. De plus, chez les soldats femelles et les reines, elles contiennent de nombreuses formations cristallines d'origine mitochondriale. Le rôle de ces glandes (sécrétion de salive ou de phéromone) est discuté.

     

Plasma prolactin levels in normal children from birth to adolescence]

Plasma prolactin levels were determined by an homologous radio-immuno assay in normal children: in cord blood, at the first day of life, during childhood and along puberty. 1. In both sexes, there is a very important secretion of prolactin during the neonatal period. 2. Longitudinal studies make obvious a different pattern of plasma prolactin in boys and in girls at puberty.     

The growth and nutrient uptake of winter wheat

Summary Measurements with an ion selective electrode under winter wheat and in adjacent fallow soil, from April to July 1976, showed that nitrate concentrations were high in the 0–25 cm zone and correspondingly lower at 50 cm, because of the extreme drying conditions. Maximum differences in nitrate concentrations between cropped and fallow soil occurred at Feekes' stages 6, 10, and 11.1 indicating periods of maximum uptake by the crop (cf Ref.⁴).Dry matter weight of wheat, sampled biweekly, was maximum 15 days before maturity. The foliage senesced and lost weight from Feekes' stage 10.1 onwards. Nutrient concentrations in the foliage decreased from Feekes' stage 4, but N, P and Mg concentrations in the ears increased during Feekes' stage 11. N, P and Mg accumulated in the ears at the expense of the foliage during stage 11, maximum uptake occurring at stages 11.3, 11.1 and 11.2 respectively. In contrast, K and Ca uptake ceased at stages 10.1 and 10.5 respectively and then both were lost from the foliage in heavy showers.Rates of N uptake and soil nitrate depletion correlated significantly, enabling N uptake to be deduced approximately from thesein situ soil nitrate measurements.