Antagonism of diazepam-induced feeding in rats by antisera to opioid peptides

Diazepam-induced feeding in rats is antagonized not only by the opiate antagonist naloxone but also intraventricular administration of specific antisera to the endogenous opioid peptides met-enkephalin or beta-endorphin. Pituitary beta-endorphin is probably not implicated in the diazepam effect since blockade with the glucocorticoid dexamethasone of the release of beta-endorphin from the anterior pituitary does not modify the diazepam-induced feeding, which is however prevented by TRH, a suggested physiological antagonist of some of the effects of opioid peptides. The possible central participation of both beta-endorphin and met-enkephalin in the ingestive behavior induced by diazepam gives further support to the postulated physiological role of endogenous opioids in appetite regulation.     

Comparative study of Agrobacterium biotypes 1, 2 and 3 by electrophoresis and serological methods

A comparative study by electrophoresis and serology of strains representing the three Agrobacterium biotypes was carried out. Thirteen Spanish isolates and strains from international collections were included. Ten antisera were prepared by using strains from the three biotypes and different types of antigens. The strains were studied by immunodiffusion, indirect immunofluorescence and indirect ELISA. Serological relationship among all the strains was observed, although serological heterogeneity within each of the biotypes occurred. Biotype 3 appears as serologically related to biotypes 1 and 2, having an intermediate position. This observation is in agreement with their biochemical characteristics. Electrophoretic analysis of the three biotypes showed that there was high variability. Three main bands appeared in the six strains studied. One specific band occurred in the biotype 1 strains and another in the biotype 3 strains.     

Giemsa stain applied to deplasticized sections to identify pancreatic islet cells

A new application of the Giemsa stain to demonstrate endocrine cells in deplasticized sections of Epon embedded material is described. Its application to the pancreas of Rana temporaria is illustrated. The technique does not require postfixation with OsO4 and is easily performed in 30 min. It allows the easy identification of three types of endocrine cells (A, B, and D). A cells, preferentially located at the islet periphery, stain purple-blue. B cells, which occupy the interior of the islet, display a lilac color. D cells give a strong purple color; they are located both in the periphery of the islets and scattered among acinar cells. Positive identification of the cell types was made by immunocytochemistry and electron microscopy.     

Plasma levels of arginine vasotocin,prolactin, aldosterone and corticosterone during prolonged dehydration in the domestic flowl: effect of dietary NaCl

Three groups of White Plymouth Rock laying hens were adapted to three levels of dietary NaCl: low-NaCl food with tap water (LOW), high-NaCl food (1% NaCl w/w added) with tap water (HT), and high-NaCl food with 0.5% NaCl for drinking (HS). The birds were subjected to water deprivation (dehydration) for 18 days. Blood sampling was done at 2-4 day intervals. Plasma concentrations of arginine vasotocin (AVT), prolactin (PRL), aldosterone (ALDO) and corticosterone (CS) were determined by radioimmunoassay. Plasma osmolality, sodium, chloride, and potassium were also determined. In the normally hydrated hens fully adapted to the diets, there was a stepwise increase from LOW to HS in plasma osmolality (305, 315, 332 mOsm, for LOW, HT and HS, respectively), [Na+] (144, 153, 161 mM) and [Cl-] (109, 119, 127 mM) as well as in [AVT] (6, 14, 18 pg/ml) and [PRL] (16, 24, 34 ng/ml). Regressing [AVT] on osmolality gave a slope of 0.30 pg . ml-1/mOsm and a threshold of 273 mOsm. The slope of [PRL] on osmolality was 0.73 ng . ml-1/mOsm. The correlation coefficient of [AVT] and [PRL] was 0.67. LOW had high [ALDO] (165 pg/ml) which was suppressed to low levels in HT and HS (5-8 pg/ml), while [CS] was the same in all groups (0.9-1.1 ng/ml). Plasma [K+] was decreased in the high-NaCl groups (5.8 mM in LOW, 4.4 and 4.7 mM in HT and HS). Dehydration resulted within 2 days generally in a sharp (5-15%) increase in osmolality, [Na+] and [Cl-], which thereafter increased more slowly during the remaining 16 days in all groups, with the slowest increase in LOW. The levels of osmolality [Na+] and [Cl-] were 5% lower in LOW than in HT and HS, which showed the same levels during the dehydration period. Plasma [AVT] and [PRL] increased 2-4 fold within 2 days of dehydration; [AVT] reached a plateau at 29 pg/ml in all groups, but [PRL] continued to rise in all groups, fastest in LOW, reaching similar levels in all groups after 14-18 days of dehydration, about 85 ng/ml. The correlation coefficient of [AVT] and [PRL] was decreased by half (to 0.32) during dehydration. Plasma [ALDO] increased in all groups with dehydration, 1.7 fold in LOW and 3-6 fold in HT and HS, but the levels reached in HT and HS were only 15-30% of that seen in LOW.(ABSTRACT TRUNCATED AT 400 WORDS)     

Cloning and sequencing of mRNAs coding for two adult alpha globin chains of the salamander Pleurodeles waltlii

A cDNA library of erythrocyte mRNAs was established from immature red blood cells of the adult amphibian, Pleurodeles waltlii (urodele; salamander). The cDNA clones corresponding to the four adult globin chains were first identified and characterized by positive selection and the cDNAs derived from the two (major and minor) alpha-globin chains sequenced. The sequences presented contain both the complete 3'-noncoding region and the coding region of both chains, with the exception of the first nine codons of the minor alpha-chain, and a portion of the 5'-noncoding region of the major chain. The amino acid sequences of the encoded alpha-globin polypeptides have been deduced and compared with those of Xenopus laevis and of man. These comparative studies suggest that the alpha-globins of Pleurodeles waltlii and Xenopus laevis may have diverged from a common ancestral gene at the time when mammalian and amphibian lines diverged, and that they then evolved separately. Duplication of the alpha-gene, which is responsible for the polypeptide heterogeneity, appears to have occurred earlier in Pleurodeles waltlii than in Xenopus laevis.     

Isolement et sélection de souches d'actinomycètes productrices de substances antifongiques de structure non-polyénique

Résumé Dans le but d'étudier des souches d'actinomycètes productrices de substances antifongiques de structure non-polyénique, 13, échantillons de sol prélevés dans le sud de la France ont été examinés. L'utilisation de milieux sélectifs a permis d'isoler 486 souches d'actinomycètes qui ont été testées vis-à-vis de quatre espèces de champignons et de levures: 18% des souches isolées sont actives sur au moins l'une des espèces utilisées. Parmi celles-ci 14 souches, productrices de substances de structure non-polyénique, ont été sélectionnées après étude des spectres d'absorption en UV des surnageants de culture, des extraits butanoliques de ces surnageants ou des extraits méthanoliques de mycélium. L'utilisation d'un test bactérien de toxicité à court terme (SOS Chromotest) a permis de montrer que 10 souches sur 14 présentent aussi une activité génotoxique.

---

Summary In order to study actinomycete strains producing non-polyenic antifungal substances 13 soil samples were collected in S. France. By using selective media 486 strains of actinomycetes were isolated and tested on four species of moulds and yeasts: 18% of the isolated strains were active against one or more of the test organisms. From these isolates 14 producers of non-polyenic antifungal substances were selected by means of u.v. absorption spectra of culture supernatant fractions, butanol extracts of these fractions, or methanol extracts of mycelium. A rapid bacterial toxicity assay (SOS Chromotest) demonstrated that 10 of the 14 selected strains had genotoxic activity.

---

Resumen Para el estudio de cepas de actinomicetes productores de sustancias antifúngicas no poliénicas, se recogieron 13 muestras de suelo en el S. de Francia. Utilizando medios selectivos se aislaron 486 cepas de actinomicetes que se ensayaron frente a cuatro especies de mohos y levaduras: 18% de las cepas aisladas mostraron actividad frente a uno o más de los organismos utilizados en el test. De estas cepas se seleccionaron 14 que eran productoras de sustancias antifúngicas no poliénicas mediante el espectro de absorción al U.V. de las fracciones sobrenadantes del cultivo, de extractos butanólicos de dichas fracciones o de extractos metanólicos del micelio. Un ensayo rápido de toxicidad bacteriana (SOS Chromotest) mostró que de las 14 cepas seleccionadas lo tenían actividad genotóxica.

     

Synthesis of hydroxy fatty acids from 4, 7, 10, 13, 16, 19-[1-14C] docosahexaenoic acid by human platelets

Human platelets incubated in the presence of 54 microM [1-14C]22:6 produced hydroxydocosahexaenoic acid (HDHE) at about half the rate with which 12-hydroxy-5,8,10,14-eicosatetraenoic acid is produced from [1-14C]arachidonic acid. More than 90% of the radioactivity in HDHE was distributed among two major isomers, 14-HDHE and 11-HDHE. The production of HDHEs was unaffected by indomethacin but completely inhibited by 5,8,11,14-heneicosatetraynoic acid, which suggests that the hydroxy fatty acids are produced by lipoxygenase. The proportions of HDHE isomers varied with the concentration of 22:6. The ratio 14-HDHE/11-HDHE was higher at 6.8 microM 22:6 than when platelets were incubated with 54 microM 22:6. It is suggested that the amounts of these isomers produced will depend both on the availability of 22:6 as well as by competition of this acid with other acids for lipoxygenase.     

Chromosomal location of the active NORs in theSteropleurus martorelli complex

The chromosomal location of the active NORs has been analyzed by a silver impregnation procedure in theSteropleurus martorelli complex. A primary NOR, which is always present at the first meiotic prophase, has been found in each of the four described races. In addition to this, all races possess one or two secondary NORs which are less active than the former and can be occasionally shown. Usually only one of the two homologous chromosomes has been found to be involved with nucleolus organisation.These results are discussed in relation to hypotheses on the chromosome differentiation of this species complex.     

Effect of parasympathetic denervation on acetylcholine levels in the rat parotid gland. Is there an extraneuronal pool of acetylcholine?

Parasympathetic denervation of the rat parotid gland by avulsion of the auriculotemporal nerve caused a marked and lasting decrease in gland weight. Parasympathectomy did not change the levels of choline in the gland but decreased by 60% the levels of acetylcholine (ACh) ten days after surgery and 65% at 28 days. It is puzzling that relatively high levels of ACh remained after parasympathetic denervation. The presence of additional cholinergic nerves that innervate the gland, or pass through it en route to other structures may account for some of the remaining ACh. Also, Schwann cells from denervated nerves might have contributed to some of the ACh. The existence of an extraneuronal source of ACh is considered.