Syngeneic sensitization of mouse lymphocytes on monolayers of thyroid epithelial cells. VII. Generation of thyroid-specific cytotoxic effector cells

During primary syngeneic sensitization of lymphocytes on monolayers of thyroid epithelial cells (TEC), lymphoblasts are generated as assessed by thymidine uptake. When these thyroid-sensitized lymphoblasts are deposited onto 51Cr labeled TEC used as target cells, syngeneic cytotoxicity (SC) occurs after 5 hr. The effector cell of this SC is a T lymphocyte, belonging to the Lyt-2 T-cell subset. Moreover, blocking experiments demonstrated that SC involves class I major histocompatibility complex and thyroglobulin (Tg) antigens. These data demonstrate that SC can be compared to the classical hapten or virus self-mediated cytotoxicity, but in this case Tg plays the role of these agents. The in vivo relevance of this SC is discussed.     

Cladocera from the Sudan: Red Sea Hills,Jebel Marra and valley of the main Nile

Twenty species of Cladocera are reported from the Nile, where lacustrine species dominate, and from Jebel Marra and the Red Sea Hills, where chydorids dominate. The community found in the Red Sea Hills is more typically desertic than that of Jebel Marra, which appears closely related to the fauna of the West and Central African Sahel.     

A revision of the Scapholeberinae (Crustacea: Cladocera)

The group of hyponeustonic daphniid cladocera previously known under the generic name Scapholeberis is raised to the rank of a subfamily (Scapholeberinae) and contains two genera, Megafenestra n.gen. (2 species), and Scapholeberis s.s. (7 species and one subspecies). The characters upon which this revision is based are: structure of the rostrum, structure of the first antennae, structure of trunk limbs 1, 2, and 5, presence and nature of headpore(s), structure of the ventral rim of the valves, armature of the distal rim of the valves, structure of the postabdomen and its end-claws. Males were examined in all but two species, and proved to be more primitive than females and much less diagnostic than in the Chydoridae. It also appeared that the shape and armature of the postabdomen are less important taxonomical tools than heretofore supposed. In more than half of the species, it is of generalised shape and hardly usable beyond the species-group level. The same, although less drastically, holds true for the P1 of males. Of greatest diagnostic value at the species level are the shape of the rostrum and the armature of the valve margins. A phylogeny of the subfamily is proposed, with Megafenestra as the more primitive genus, closely allied to Ceriodaphnia, and within Scapholeberis, S. mucronata as the most apomorphic species. In biogeographical respect, no species is cosmopolitan, although their ranges may be of continental dimensions. Species and populations appear to concentrate in the temperate and continental climate belts of the northern hemisphere, but more research in the southern hemisphere is needed. A key for the identification of all species is given.     

Répartition de l'activité phosphatasique acide dans les cellules gonadotropes de la Grenouille au cours de leur cycle sécrétoire

Résumé Dans les cellules de l'hypophyse de la Grenouille, Rana temporaria, produisant l'hormone gonadotrope, nous avons analysé la localisation et l'évolution de l'activité phosphatasique acide au cours du cycle sécrétoire.Durant l'élaboration des sécrétions, l'activité enzymatique est essentiellement localisée au niveau de l'ergastoplasme, des saccules et des vésicules golgiennes, avec quelques accumulations plus importantes dans les grains juxta-golgiens et dans certains grains de diamètre plus important. A ce stade, quelques vésicules du réticulum endoplasmique lisse et un petit nombre de formations globuleuses présentent également une réaction positive. Ces images pourraient être en relation d'une part avec un processus de formation des lysosomes, d'autre part avec le fonctionnement normal de l'appareil de Golgi.Dans les cellules en phase de stockage et en cours d'excrétion, aucune activité n'est décelable dans la région golgienne. On note, par contre, la présence d'un grand nombre de corpuscules lytiques dispersés parmi les grains de sécrétion. Dans la matrice de ces corpuscules on distingue parfois des formations granulaires qui pourraient être en voie de résorption.Ces formations qui interviennent dans le processus de résorption intracellulaire des produits de sécrétion non excrétés pourraient également à certains moments du cycle cellulaire jouer un rôle, dans le processus de libération de l'hormone.

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Localization of phosphatasic acid activity in gonadotrophs of the frog during their secretory cycle

Summary The localization and evolution of acid phosphatase activity during the secretory cycle of the gonadotropic cells of Rana temporaria are described.During the secretory phase of the cells the enzymatic activity is demonstrable in the rough endoplasmic reticulum, the Golgi saccules or vesicles and in granules of different diameters. Some vesicles of the smooth endoplasmic reticulum and a few number of globular formations contain also acid phosphatase. This picture corresponds to the normal function of Golgi zone or to the first step of the formation of lysosomes.During the phases of accumulation and excretion of secretory granules acid phosphatase activity is concentrated in lytic bodies which sometimes contain secretory granules. This picture may be interpreted as an intracellular digestion of secretory products. At this time the Golgi zone lacks acid phosphatase activity.From these findings it may be concluded that in gonadotropic cells lysosomes act in the regulation of secretory process, specially the resorption of accumulated secretory granules, but a role in the hormone releasing process cannot be excluded.

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Avec la collaboration technique de Mme R.-O. Clauss.     

The Distribution of Acidic and Neutral Peptidases in Barley and Wheat Kernels

The activity of barley and wheat peptidases which hydrolyze alpha-N-benzoyl-dl-arginine-p-nitronnilide (BAPA) and alpha-N-benzoyl-l-arginine ethyl ester (BAEE) has been measured in proximal and distal portions of ungerminated grain and in these tissues during 6 and 7 day incubations. The proximal portion of ungerminated barleys contained the major part of both the acidic (BAPA-ase and acidic BAEE-ase) and neutral (neutral BAEE-ase) peptidases. In ungcrminated wheat these acidic and neutral peptidases were nearly evenly distributed between the proximal and dislal portions. Commercial wheat embryo was very high in acidic peptidase but contained no neutral peptidase. During the germination of both wheat and barleys, acidic and neutral peptidase activity in the seedlings increased with time. No such consistent increase was observed for aleurone and starchy endosperm tissue for any of these grains. Aleurone and starchy endosperm tissue incubated in the absence of the proximal portion of the kernel showed reduced peptidase activities.     

Stimulation of root and somatic embryo production in Euonymus europaeus L. by an inhibitor of polyamine biosynthesis

In vitro formation of roots and somatic embryos is obtained from cotyledon explants of a Spindle tree (Euonymus europaeus L.) cultured on two different media: a medium inducing callus formation and the production of roots, and a medium inducing callus formation, root and somatic embryo production. We studied the effects of -difluoromethylornithine (DFMO), a specific, irreversible inhibitor of ornithine decarboxylase (ODC) on root and somatic embryo production, growth and titers of putrescine in Euonymus explants and explant-derived calli. Early changes in putrescine levels were detected in both cultures before the visible emergence of roots or somatic embryos. DFMO rapidly inhibited putrescine accumulation and growth in non-embryogenic calli and highly stimulated rooting activity. DFMO partially inhibited putrescine accumulation in embryogenic calli. This inhibition had no effects on callus growth but significantly reduced the time of emergence of roots and highly stimulated somatic embryo production. The relationship among putrescine, putrescine metabolism, growth, root and somatic embryo formation is discussed.     

Impact of Chlorine and Heat on the Survival of Hartmannella vermiformis and Subsequent Growth of Legionella pneumophila

Hartmannella vermiformis, a common amoebal inhabitant of potable-water systems, supports intracellular multiplication of Legionella pneumophila and is probably important in the transportation and amplification of legionellae within these systems. To provide a practical guide for decontamination of potable-water systems, we assessed the chlorine and heat resistance of H. vermiformis. H. vermiformis cysts and trophozoites were treated independently with chlorine at concentrations of 2.0 to 10.0 ppm for 30 min and then cocultured with L. pneumophila. Both cysts and trophozoites were sensitive to concentrations between 2.0 and 4.0 ppm and above (trophozoites somewhat more so than cysts), and 10.0 ppm was lethal to both forms. Hartmannellae treated with chlorine up to a concentration of 4.0 ppm supported the growth of legionellae. To determine whether heat would be an effective addendum to chlorine treatment of amoebae, hartmannellae were subjected to temperatures of 55 and 60°C for 30 min and alternatively to 50°C followed by treatment with chlorine at a concentration of 2 ppm. Fewer than 0.05% of the amoebae survived treatment at 55°C, and there were no survivors at 60°C. Pretreatment at 50°C appeared to make hartmannella cysts more susceptible to chlorine but did not further reduce the concentration of trophozoites.     

Adult thymectomy promotes the manifestation of autoreactive lymphocytes.

Spleen cells from adult thymectomized mice (ATX) were assayed in a syngeneic graft vs host (GVH) model based upon enlargement of the draining popliteal lymph node following syngeneic cell inoculation into the hind footpad. Spleen cells from ATX mice have been found to induce a significantly higher increase in the weight of the regional lymph node than that induced by the injection of normal spleen cells. Irradiated spleen cells from ATX donors did not cause a similar increase, suggesting either that proliferation of the transferred cells was required at some stage of the reaction or that autoreactive cells are radiosensitive. Autoreactive cells were found in the spleen of mice 2 to 3 months after the thymectomy but were never found in the lymph nodes of such animals or in the thymus of intact mice. They are not phagocytic adherent cells and are not retained on nylon wool columns, which suggests that they belong to the T-cell lineage. Autoreactivity is lost when spleen cells from ATX donors are depleted of autologous rosette-forming cells (A-RFC) by centrifugation on a Ficoll-Hypaque gradient after rosette formation. Autoreactive spleen lymphocytes might belong to the population of A-RFC previously characterized as a population of immature T cells.     

The circular dichroism of tumor necrosis factor-α: Measurement into the vacuum UV and analysis for secondary structure

The circular dichroism (CD) spectrum of tumor necrosis factor-α has been measured into the vacuum UV to 168 nm. Analysis of the CD for secondary structure is in good agreement with X-ray diffraction results, but the analysis is somewhat unstable. Adding the CD of this protein together with its X-ray determined secondary structure to the basis set should improve subsequent analyses of CD spectra for other all-β proteins.