Showing papers by "Institut national de la recherche agronomique published in 1973"

Structure primaire de la caséine β bovine

Abstract: In a previous report [1], we have given the complete primary structure of ϰB1-caseinomacro-peptide which is the soluble COOH-terminal fragment split from bovine ϰB1-casein by rennin. We also reported on the COOH-terminal sequence of the NH2-terminal fragment, the so-called para-ϰ-casein. The present paper deals with the complete amino acid sequence of bovine ϰB-casein, which has now been achieved by establishing the primary structure of para-ϰB-casein of which we discuss the salient features. This work has been reported briefly in a short communication [2]. SCM-para-ϰB-casein and maleyl ϰBCN1, the NH2-terminal cyanogen bromide fragment of ϰB-casein [1], were used as starting material. The tryptic and peptic peptides of SCM-para-ϰB-casein and the chymotryptic peptides of ϰBCN1 were isolated on Dowex 50 and Sephadex G-50 or G-25, and their sequences were determined either partially or completely by using classical methods and in some cases mass spectrometry. All these peptides and a NBS fragment of SCM-para-ϰB-casein have provided all the overlaps needed for the completion of the amino acid sequence of para-ϰB-casein. Para-ϰB-casein is a single polypeptide chain containing 105 amino acid residues: Asp3, Asn4, Thr3, Ser7, PyroGlu1, Glu4, Gln12, Pro12, Gly1, Ala9, Val5, 1/2 Cys2, Met1, Ile6, Leu7, Tyr9, Phe4, Lys6, His3, Trp1, Arg5, and its molecular weight has been calculated to be 12269. The average hydrophobicity, calculated according to Bigelow [3], is 5.48 kJ (1.310 kcal) per residue, and para-ϰB-casein can be therefore considered to be a very hydrophobic molecule. Its net positive charge at pH of native milk (about 6.8) is very close to 4.5. The high content (11.5%) and rather uniform distribution of prolyl residues are incompatible with much α-helical organization of the molecule, as previously shown for ϰ-casein [4]. Both hydrophobic and charged amino acid residues are distributed non-uniformly along the chain. Two regions, 1–24 and 80–105, are hydrophilic: the very hydrophilic former, with NH2-terminal pyroglutamic acid, contains a cysteinyl residue located inside a cluster of eleven ionizable residues including six out of the seven total dicarboxylic amino acids; the 80–105 region, which contains the second cysteinyl residue in position 88, is rather hydrophilic, except at the COOH-terminal end which is hydrophobic in spite of the presence of a cluster of four basic residues. These two hydrophilic regions are very likely to be on the outisde of the molecule and this may favor the formation of intermolecular S-S bonds. The very hydro-phobic central part of the chain, viz., 25–79, where most of the aromatic residues are located, has a para-ϰ-casein-like behaviour in aqueous solution, and it may be responsible for the aggregation ability of para-ϰ-casein. According to the sequence data of both ϰB1-caseinomacropeptide [1] and para-ϰ-casein, it is concluded that bovine ϰB-casein is made up of a single polypeptide chain containing 169 amino acid residues: Asp4, Asn7, Thr14, Ser12, SerP1, PyroGlu1, Glu12, Gln14, Pro20, Gly2, Ala15, Val11, 1/2 Cys2, Met2, Ile13, Leu8, Tyr9, Phe4, Lys9, His3, Trp1, Arg5, with NH2-terminal pyroglutamic acid. However, in accordance with the well-known lability of glutamine residues in NH2-terminal position [5], such a pyroglutamic acid residue may arise from the subsequent cyclisation of a NH2-terminal glutamine residue present originally in native ϰ-casein. The content of proline residues is high (11.8%). The molecular weight of the carbohydrate-free monomer of ϰB-casein is 19023. Its net negative charge at pH of native milk is close to 3.5 and its average hydrophobicity is about 5.37 kJ (1.285 kcal) per residue. We have already reported [6] the location of the two amino acid substitutions differentiating the two known genetic variants : the B variant differs from the A variant by the respective amino acid substitutions Ile 136/Thr and Ala 148/Asp. Tryptic and chymotryptic peptides isolated by Jolles et al. [7] from ϰA-casein correspond obviously to the fragments 11–16, 17–25,31–34, 63–67, 1–10 and 86–105 of ϰ-casein strand, but there is only partial agreement concerning the sequences of amino acid proposed for the last three fragments. More recently, Fiat et al. [8] have studied a short glycopeptide isolated from bovine ϰ-casein, but neither the amino acid sequence nor the location of the phosphate group agree with our results.

LRF producing cells of the mammalian hypothalamus. A fluorescent antibody study.

Abstract: The demonstration of perikarya of mediocellular neurones producing LRF, using indirect immunofluorescence on slides and anti synthetic LRF antibodies, requires both their activation and the inhibition of their axoplasmic transport. This fact suggests that LRF is present in an immunoreactive form, but usually in very low concentrations. Perikarya of neurons producing LRF are found principally in the preoptic and septal areas of the rat and decrease caudally, particularly beyond the retrochiasmatic area. Most of the axons coming from these perikarya are incorporated in the hypothalamoinfundibular tract and terminate around the capillaries of the primary portal plexus, particularly those of interealar plexus. Other axons (or axon collaterals) may be found in various areas (suprachiasmal crista, epithalamus, amygdala, mesencephalon) and form circuits recalling the “extrahypophyseal pathways” described for the magnocellular Gomori-positive neurons of the SON and PVN. These axons are probably concerned in intersegmental regulations involving “neurosecretory synapses”, particularly of the axosomatic type. The placement of stereotaxic lesions was used to determine the topography and direction of axoplasmic flow of the axons transporting LRF. The infundibular immunoreactive material, already discernible at the end of gestation in the foetus, shows considerable variations between birth and puberty, during the estrous cycle and under various other physiological or experimental conditions. The observations made under various experimental or physiological conditions suggest that, in the guinea-pig in particular, the greater part of the hypothalamic immunoreactive material is concentrated in the infundibular area. This area of accumulation is comparable to the distal neurohypophysis of the Gomori-positive neurosecretory system coming from the SON and PVN.

Plant Mycoplasmas: Serological Relation between Agents Associated with Citrus Stubborn and Corn Stunt Diseases.

Abstract: Growth-inhibition and precipitin tests established that antigens of the helical mycoplasma-like organism (Spiroplasma citri) associated with citrus stubborn disease are serologically related to antigens in corn infected with stunt disease but not in healthy corn

Stimulation of anti-Brucella vaccination in mice by tetramisole, a phenyl-imidothiazole salt.

Abstract: The effect of tetramisole (hydrochloride of racemic 2, 3, 5, 6,-tetrahydro-6-phenyl-imidazo [2, 1-b] thiazole) on immunization was investigated in mice vaccinated by killed Brucella melitensis cells suspended in incomplete adjuvant. Immunity to Brucella abortus challenge was estimated by the reduction in number of B. abortus colonies per gram of spleen in those mice which escaped full immunization and also by calculation of mean infective doses for each group of mice. All tetramisole treatments significantly reduced the number of B. abortus live cells in spleen from infected mice. Tetramisole, injected twice (at the time of vaccination and 48 h later), induced a significant 3.5-fold increase of the protection brought about by Brucella vaccine alone. A single injection of 1.25 mg/kg at the time of vaccination resulted also in a significant increase of the immunity given by vaccination. No modifications of the vaccine potency were observed if tetramisole administration preceded vaccination. In such a mouse assay, tetramisole-induced stimulation was not accompanied by specific antibody increases, although measured by three serological tests.

The Influence of the Christiansen Effect on I.R. Spectra of Powders

Abstract: The Christiansen effect appears in the i.r. spectrum of powders embedded in a solid, liquid or air matrix as an apparently anomalous transmittance (Christiansen peak) of the incident elec- tromagnetic radiations. The peak appears at wavelengths for which the refractive index of the sample and the refractive index of the matrix are equal (Christiansen wavelength: Ach,). On account of the great variation of the sample refractive index in the immediate neighborhood of the absorption bands (anomalous dispersion curve), one often observes the occurrence of a transmit- tance peak or of a band deformation in this spectral range. A change in the position of this transmission peak with the value of the matrix refractive index is indicative of the Christiansen effect. The equality of the refractive indices of the sample and of the matrix for AChr has been used to determine some points of the anomalous dispersion curve in the neighborhood of the hydroxyl stretch- ing band (3678 era-t). Spectral distortions caused by the Christiansen effect can be reduced by preparing the sample in such a manner that the width at half-maximum (Av~2) of the Christiansen peak is several times greater than this of the absorption band itself. Clarke's theoretical formula, which gives an estimation of Avl~2, has been qualitatively verified and thus gives an appropriate guide in the choice of the parameters which one can optimize during the sample preparation. One can reduce the Christiansen effect spectral modifications, without running the risk of modifying the sample itself, particularly by overly severe grinding.

Characterization of the mycoplasma‐like organism associated with “stubborn” disease of citrus

Abstract: The mycoplasma-like bodies associated with “stubborn” disease of are probably the first mycoplasma-like organisms of plant origin to have been obtained in pure culture.1k12 Our belief that the grown organism was not the result of contamination by an animal or human mycoplasma was based on the following: 1. The organism was obtained only from “stubborn”-affected citrus leaves, never from similar healthy control leaves growing next to diseased material. 2. The organism was grown consistently in 17 independent experiments with “stubborn”-affected leaves, but never in 11 independent assays with healthy leaf material.” Later, the agent was isolated in 22 out of 28 experiments. 3. Sterility controls, including uninoculated liquid and solid media, were used in each experiment and never showed any signs of microbial growth. 4. The possible presence of contaminating mycoplasmas in the medium was always checked. Before use, five-liter batches of complete medium containing one liter of foal serum were routinely incubated at 32°C for 14 days. The medium was then centrifuged and the very small pellet obtained was “inoculated” on solid growth medium. Under these conditions none of the media used yielded mycoplasma growth or any other type of growth. 5 . Successful isolations and growth of the mycoplasma-like organism were obtained not only with one source of stubbornly affected material, that from California (strain C 189, kindly supplied by Dr. E. C. Calavan),*O but also with material from Morocco (strain R8 A2) ,11,12 Further isolates came from California (strain CES 3033) and from Morocco (Tadla area strain R7 A10 and Rharb area strain R D A9). 6. Identical results were obtained independently by Fudl-Allah and coworkers in Ca1ifornia,4s5 particularly with stubborn strain C 189, one of those used by Saglio and colleagues. That both California and Morocco isolates resembled mycoplasmas was based upon their colony morphology (“fried egg”), the ultrastructure of the organisms in liquid and solid media, their resistance to penicillin, the absence of reversion to walled forms after ten passages in penicillin-free medium or after isolation and cultivation in the total absence of any antibiotic, and their low G 4C content (26 -+ 1 mole % ) To characterize further the microorganism associated with stubborn disease of citrus, it remained necessary to identify the organism serologically, to determine

Manufacture of cheese from ultrafiltered milk

Abstract: Cheese is made from heat treated milk and without the conventional draining of whey by a process which involves ultrafiltering milk to produce a milk concentrate having essentially the composition of cheese produced by conventional whey draining processes, sterilizing by heating the milk before or after ultrafiltration, adding rennet to the concentrate to cause coagulation and to produce cheese curd, and converting the curd into cheese. This process enables the milk before or after ultrafiltration to be heated at temperatures of 110* to 150*C without making the milk more difficult to coagulate with rennet as normally occurs when milk is heated to high temperatures.

[Localisation by immunofluorescence of secretions related to thyreotropins, gonadotropins and corticotropins in axolotl pituitary(Ambystoma mexicanum, Shaw (author's transl)].

Abstract: Les anticorps anti-TSH (hormone thyreotrope) d'origine bovine, anti-LH β (hormone luteinisante) d'origine ovine et anti β (1–24) corticotropine de synthese ont ete appliques a l'hypophyse de l'Axolotl (Ambystoma mexicanum, Shaw) selon une technique d'immunofluorescence histologique indirecte. Les anticorps anti-TSH se fixent sur une population de cellules fusiformes localisees dans les regions caudale et ventrale de l'hypophyse distale. Les elements reveles par les anticorps anti-LH β possedent un noyau ovalaire entoure d'un cytoplasme intensement fluorescent et sont repartis dans l'ensemble du lobe hypophysaire distal. Les cellules fixant l'anticorps anti β (1–24) corticotropine sont disposees en bordure de l'eminence mediane et presentent un noyau ovalaire et un cytoplasme abondant. Il s'agirait respectivement des cellules a fonction thyreotrope, gonadotrope et corticotrope. L'examen des caracteristiques cytologiques et histochimiques de ces trois types cellulaires complete ces donnees immunologiques.

[Ultrastructure of Leydig and Sertoli cells in the testicular cycle of the Pekin duck. Biochemical and cytoenzymological correlations (author's transl)].

Abstract: L'ultrastructure des cellules de Leydig et des cellules de Sertoli du testicule du Canard Pekin a ete etudiee au cours de la phase printaniere du cycle sexuel, soit de janvier a juillet. Parallelement on a effectue chez les meemes animaux la recherche histochimique de la Δ5-3 β-hydroxysteroidedeshydrogenase (Δ5-3 β-HSDH) ainsi que le dosage, par chromatographie en phase gazeuse des steroides androgenes dans le plasma veineux peripherique et dans le testicule.

[Detection of corticotropic and melanotropic cells in the hypophysis of the frog, Rana temporaria in the course of the development (author's transl)].

Abstract: During the embryonic and larval developmental stages of the frog, Rana temporaria L, anti-β 1–24, α 17–39 corticotropine, α and β MSH antibodies were used to define, with immunofluorescence technique, the appearence of corticotropic and melanotropic cells. A very small number of fluorescent corticotropic cells appears for the first time during the embryonic stage (10 mm), just before the differentiation of the pars intermedia. The cells are small, their large nucleus is surrounded by a fine rim of fluorescent cytoplasm. During premetamorphic stage, the anti-ACTH antibodies (anti-β 1–24 and anti-α 17–39 corticotropine) reveal more fluorescent cells in the whole pars distalis. The pars intermedia cells can also be visualized by both antisera. At the end of prometamorphosis and during climax the corticotropic cells show a more precise localization. As in adult frog pars distalis, they are concentrated in the rostral half of the lobe. With the same technique anti-α and β MSH antibodies reveal only the cells of the pars intermedia. No other cell type of the pars distalis reacts with these antibodies. This technique has the advantage to show that the ACTH and the MSH cells appear very early during the embryonic life.

Les protéines des corps d'inclusion desBaculovirus: II. — Étude comparée de six granuloses

Abstract: La comparaison des granules ou des proteines de granules desBaculovirus dePieris brassicae, Pygaera anastomosis, Hyphantria cunea, Carpocapsa pomonella, Mythimna unipuncta, Mamestra oleracea a ete entreprise par les techniques d'electrophorese, d'agglutination, d'immunofluorescence et de precipitation en gel. L'electrophorese fait apparaitre l'etroite ressemblance qui existe entre les proteines des six sortes de corps d'inclusion. L'analyse immunochimique montre que chaque granule est bien distinct de tous les autres; elle peut servir de base a l'identification des divers virus.

Reconstitution d'un ancien peuplement forestier en forêt de Fontainebleau par l'étude anatomique de charbons de bois et leur datation par le 14C

Abstract: ResumeL'identification anatomique et la datation au 14C des fragments vegetaux carbonises recoltes dans les sols de la « Tillaie » (une parcelle en Reserve biologique a Fontainebleau) a montre une extreme constance du peuplement forestier depuis le 8e siecle. La composition en espece a peu varie, de meme, semble-t-il, que les pourcentages relatifs. Ces faits sont confirmes par le diagramme pollinique.

Process for preventing trace element deficiency in animals and compositions for carrying out said process

Abstract: A process for preventing trace element deficiency in animals and injectable compositions are described. The trace element compounds are put in suspension in an oil, such as purified olive oil. The said compounds are in an insoluble, non ionizable form, which is solubilized slowly by a moderate inflammatory reaction. In the case of copper, a suitable form is powdered copper or copper oxide. For zinc, zinc oxide or zinc is used. For manganese, the oxide Mn3O4 is prefered. The compositions are administered to ovines, or bovines by intramuscular or subcutaneous injections.

Thermorésistance anormale de spores bactériennes chauffées par injection directe dans la vapeur

Abstract: Abnormal heat resistance of bacterial spores heated by direct injection into steam Spores of Clostridium tyrobutyricum, Bacillus cereus and B. stearothermophilus were heated in a pilot-plant D.H.T. sterilizer, of the milk-into-steam type. Temperatures were chosen between 102 and 115°C, and the mean holding time was about 10 sec. Working fluids were buffer, whole milk or skim milk. Distribution function for residence times was determined by means of methylene blue as a tracer. Theoretical sporicidal effectiveness was calculated for each strain and each temperature, using heat resistance values previously determined by heating spores in T.D.T. tubes. With Cl. tyrobutyricum and B. cereus the experimental sporicidal effectiveness was always higher, fram 1.2 ta 7 times, than the computed effectiveness. Furthermore, with Cl. tyrobutyricum spores, the T.D.T. curve is modified : z increases (13° C instead of 9.8° C in T.D.T. tubes.) B. stearothermophilus spores heated in the same D.H.T. sterilizer were partially inactivated at a temperature at which heating in ampoules results in an activation.

Remarques sur le métabolisme respiratoire de Kluyveromyces fragilis Van Der Walt

Abstract: Le metabolisme respiratoire de Kluyveromyces fragilis presente des differences importantes avec celui de Saccharomyces cerevisiae. L'effect glucose qui est tres important chez S. cerevisiae (Ephrussi 1966) est inexistant chez les Kluyveromyces. La concentration en glucose n'a pratiquement pas d'influence sur l'activite respiratoire. Le metabolisme fermentaire des Kluyveromyces est moins actif que celui des Saccharomyces. Il est sensible a l'action inhibitrice de l'air. Cependant l'effet Pasteur est moins important que chez S. cerevisiae. Le metabolisme respiratoire est generalement plus actif que le metabolisme fermentaire (Q) Chez les Kluyveromyces.

Estimation of number and diameter of isodiametric spherical particles in microtome sections

Abstract: SUMMARY In microtome sections small invisible and unrecognizable fragments cause errors in estimation of particle number and diameter. These errors can be reduced by rejecting fragments whose apparent diameter is larger than the true radius of the particles. Formulae for the calculation of diameter and number are given and the size of the errors is examined.

Les protéines des corps d'inclusion desBaculovirus III. Étude comparée de la granulose dePieris brassicae et de la polyédrose deBombyx mori

Abstract: L'etude des proteines des granules dePieris brassicae L. et des polyedres nucleaires deBombyx mori L. par les techniques de filtration sur gel, d'electrophorese et d'immunodiffusion revele de nombreuses ressemblances. La comparaison des proteines des corps d'inclusion engendres par lesBaculovirus des Lepidopteres contribue a montrer l'homogeneite de ce groupe.

Possibilitiés de régulation des populations d'Aleurothrixus floccosus Mask. (Homopt., Aleurodidae) sur agrumes par Cales noacki How. (Hymenopt, Aphelinidae)

Abstract: Sommaire Pour Iutter contre Aleurolhrixus floccosus Mask., ravageur des agrumes, 400 femelles du parasite Cales noacki How. sont lâchees dans un verger. Le schema general de 1evolution des populations de l'aleurode, avant ['introduction du parasite, est expose. L'action de l'entomophage est ensuite determinee par la comparaison de la densite des ceufs du ravageur avant et apres l'introduction de l'agent regulateur. Quinze mois apres un seul lâcher du parasite, les populations de l'aleurode se sont effondrees d'une fa&cLon spectaculaire.

Sélection d'une souche de Bacillus thermophile pour la mesure de l'efficacité stérilisatrice des installations U.H.T.

Abstract: Une souche de Bacillus coagulans, atypique pour la température optimale de croissance (650 C), et pour sa thermorésistance, a été sélectionnée pour servir à la mesure de l'efficacité stérilisatrice des installations V.H.T. Les caractéristiques de la thermorésistance des spores dans le lait V.H.T. sont: 1,9 ,;;;D= ,;;;2,5 mn, 10 ,;;;z ,;;;11,50 C. La croissance dans le lait V.H.T. est accompagnée d'une modification visible et caractéristique du lait. Le nombre de spores survivantes peut être obtenu par numération dans un milieu de culture solide ou dans le lait V.H.T. si on lui a ajouté 5,6 mg/I de fer, 20 mg/I de calcium et 24 mg/I de magnésium. L'addition de ces cations au lait ne modifie pas la thermorésistance des spores.