Jacqueline Bride

Immunocytochemical localization of insulin-related peptide(s) in the central nervous system of the snail Helix aspersa Müller: involvement in growth control.

Summary1.The presence of insulin-like substances has been demonstrated by immunocytochemistry in the central nervous system of the snailHelix aspersa.2.The immunopositivity has been observed especially in the large perikarya of the mesocerebral green cells [the cerebral green cells (CeGC) stained in green by the alcian blue: alcian yellow technique].3.The removal of either the mesocerebrum or the CeGC stops the growth of the snail and induces the increase of the glycogen content in the mantle edge.4.Our results show the existence of insulin-like material in the neurosecretory cells. Previous data having demonstrated the presence of specific binding sites to insulin in the cephalic ganglia ofHelix aspersa, one may suggest that insulin could play a neuromodulatory or a neurotransmittory role in the central nervous system and might control the growth.

Etude in vitro de l'influence des corps dorsaux sur l'ovogenèse d'Helix aspersa müll

Infantile gonads of Helix aspersa were cultured in vitro for 13 days, alone, associated with dorsal bodies, or with cerebral ganglia (surrounded by connective tissue containing the dorsal bodies). The results demonstrate the stimulatory effect of the dorsal bodies on oocyte growth and suggest that the cerebral ganglia have an inhibitory influence on dorsal body activity and/or on oocyte development.

Structural and immunohistological modifications in olfactory bulb of the staggerer mutant mouse

In the present study, we describe the structural and cytological changes observed in staggerer mutant olfactory bulbs, as compared to normal mice. On the basis of photonic and ultrastructural observations we tried to define the alterations induced by the mutation: i.e. a reduction of bulb size, a reduction in the volume of three out of the six architectonic layers (glomerular, external and internal plexiform), a reduction of glomeruli size, a loss of half the mitral cells and a slight decrease in juxtaglomerular interneuron number. In staggerer, an hypertrophy of glial ensheathing cell processes was especially evident at the level of each glomerulus, whereas the density of the astrocyte network was weaker in the granular layer and the nerve layer not apparently impaired. An immunofluorescent labelling study combined with confocal scanning microscopy was performed in order to identify the cellular type and the differentiation degree of the various elements. Antibodies anti-GFAP, a protein present in both ensheathing cells and astrocytes, and anti-OMP, the specific maturation protein of the nerve layer, were used for that purpose. Data confirmed the reality of the gliosis and the persistence of the sensory component in the mutant. All the structural alterations described in staggerer olfactory bulb were in close agreement with the functional troubles previously recorded. Our results are discussed in connection with the present knowledge on embryonal origin, fetal development and adult cellular renewal of the olfactory bulb.

Changes at the ecto-mesodermal interface during development of the duck preen gland

SummaryAn ultrastructural investigation of the organogenesis of the duck preen gland showed variations at the ecto-mesodermal interface in the course of development. During the period of invagination, ectoderm and mesoderm were separated by a continuous basal lamina. Morphogenesis of the tubules is characterized by a preferential deposition of non-oriented collagen fibres localized at the branching sites. Direct contacts between ectodermal extensions and mesodermal cells, through gaps in the basal lamina, appeared at the end-buds after the morphogenetic pattern was established and before the onset of the glandular secretory activity. The correlation between the modification of the ecto-mesodermal interface and the differentiation of uropygial ectoderm is discussed.

Mating and 20-hydroxyecdysone cause increased galactogen synthesis in the albumen gland explants of Helix aspersa (mollusca)

Abstract 1. 1. Mating causes a significant increase in [14G]glucose incorporation into newly synthesized galactogen by albumen gland explants of Helix aspersa. 2. 2. 20-Hydroxyecdysone, irrespective of the concentration used did not increase galactogen synthesis in albumen gland explants in virgin snails. 3. 3. In mated snails immediately following egg-laying, 20-hydroxyecdysone at a concentration of 10−8M caused significant increase in galactogen synthesis in albumen gland explants. 4. 4. In mated snails prior to egg-laying, a 10−7 M concentration of 20-hydroxyecdysone was required for the maximum increases of [14C]glucose uptake into galactogen. 5. 5. These results suggest that 20-hydroxyecdysone plays a hormonal role in controlling galactogen synthesis in the albumen gland of H. aspersa.

Localization of a fibronectin-like molecule in the ovotestis of the snail Helix aspersa

SummaryAn antifibronectin antibody has been prepared which recognises a fibronectin-like substance isolated from Helix aspersa hemolymph. By use of the indirect immunofluorescence technique, the distribution of fibronectin in embryos and in the ovotestis at selected development stages from hatching to the adult has been investigated. In embryos, the basement membranes and the epithelia were immunoreactive, whereas the mesenchyme and the gonadal rudiment were not. After hatching, the fibronectin was present in ovotestis. It was localized on the epithelia of gonadal acini and at the periphery of the periacinar vesicular tissue. This adhesive molecule is present on the nurse cells, which sustain the group of male cells, while it is absent on differentiating male cells in the lumen of acini. The membrane of oocyte did not exhibit fluorescence. By contrast the surface of follicular cells were clearly labelled. Inside the vitellogenic oocytes, granular fluorescence was also observed.The participation of fibronectin in gonadal organogenesis is discussed in relation to cellular adhesion and movement. Its role in the metabolic exchanges between the germinal cells and the surrounding tissues is suggested.

Action de l'extrait de tentacules oculaires d'Escargots juveniles et adultes sur le développement in vivo de la glande à albumen d'Helix aspersa

Injected optic tentacle homogenates in Helix aspersa were shown to cause a decrease in growth rate and albumen gland development. The effects of optic tentacles removed from young animals and from adult animals were compared. In young animals, injections of adult optic tentacle homogenate resulted in a reduction in both growth rate and albumen gland weight. In older adult animals injected with adult optic tentacle homogenate, growth and albumen gland development decreased, but not to the same extent as in young animals. In contrast, the inhibitory effect of the young tentacle homogenate was inverted. The possible source of a tentacular factor is discussed in relation to its possible origin in other investigated pulmonates, and also the mechanism of the homogenates heterochronic action.

Effect of temperature on haemolymphatic glucose and albumen gland polysaccharides during dormancy in the snail Helix aspersa maxima

1. 1. In artificial hibernation at 6°C, a rapid decrease in haemolymph glucose concentration occurred up to the third month and thereafter decreased slowly. The wet weight of the female albumen gland increased and its glycogen content increased after the third month whereas galactogen levels remained constant. 2. 2. At 18–20°C, in dryness (artificial estivation), haemolymph glucose remained constant. The albumen gland sustained a drastic decrease in wet weight. Its glycogen and galactogen were lost after the third month. 3. 3. The results suggest that a low temperature during a 6-months artificial dormancy of Helix aspersa maxima would promote reproduction.

Cytological survey of mouse olfactive bulb in slice culture

EARLY INTERACTIONS OF FELINE IMMUNODEFICIENC\ VIRUS WITH CULTIJRED FELINE KUPFFER CELI,S : BIOCHEMICAL AND IJLTRASTRUCTURAL STUDIES. BlNGEN Annick. MARTIN Jean-Pierre, BRAUNWALD Jacqueline, NONNENMACHER Huguette, VALLE Michtle, KOEHREN Francolse, GlJT Jean-Pierre and KlRN AndrC-. iNN3Al II 74. .In.t~ti~// tic I ‘,rolog/a, linrver.vr/c~ I,OIII.~ J’UVICW. (i7000 S/rtr.\hrwr~. j.j.U//LC’. Kupffer cells (KC) which arc liver macrophages presenting the CD9 viral receptor arc permissive for in vitro reptication.(Martin J-P, Bingcn A, Braunwald J, Nonnenmacher H. Valle M, Gut J-P, Koehrcn F, de Monte M and Kim A (1995). AIDS. 9, 447-453). Iiowever, 111 situ hybrltlization sho\ved \,lral RNA 111 only 2% ofthe cells. In order to investigate whether the first events of KC infection are Impaired and responsible for the weak permissivity, we studied these different steps from viral adsorption till DNA synthesis The bindmg of the virus at 4°C was very fast and masunat at t .5 and 3 hours. Viral internalization after lrypsin treatment was maximal after I5 minutes at 37°C but only affected 40% of the adsorbed virus as dctennined 11~ RI activity. Electron microscopic study showed that I’IV particles cntercd into KC by two main routes ptinoc.ytosis and phngocytosis, this latter concerning 909/o 0 f the virus as determined by quantification after cytochalasin I3 (1.113) treatment However plnocytosis which was not impalrcd by the phagocytosis inhibitor (CB) was the only one effective way for viral replication As a matter of fact the same quantity of replicative viral RNA and DNA determined by R’l‘-I’CR and PCR was found with or lvithout CB treatment The rcpticative forms of DNA were studied in KC and In permissive crf:K cells The quantity of2-L’I‘R circular form \\as 6 to 8 times greater In K;C than III CrFK Only viral particles which entered KC by plnocytosis could replicate. The first events in viral infection were not impaired In KC and were not responsible for the weak infectivity. The high amount of abortive form of DNA could partially explain the low permissivity of KC.

Direct intercellular contacts at the ectomesodermal interface during the duck embryologic preen gland development.

The epidermis, which lines the uropygial invaginations and which then forms the primary and secondary buds, is separated from the mesenchyma by an uninterrupted basal lamina. Between the end of the internal morphogenesis and the beginning of the secretory activity, direct intertissular contacts are established through the gaps in the basal lamina. They appear to be related to the induction of glandular differentiation.