The relation between capillaries and neurons in the caudal neurosecretory system of Pomatomus saltatrix.

The caudal neurosecretory system of Pomatomus saltatrix was examined. Particular interest was devoted to the perikarya of the neurosecretory cells. The majority of these cells were characterized by a close association with the capillary network. The cells appeared to ensheath the capillaries thus bringing the nucleus and perinuclear cytoplasm into close association with the capillaries.     

A new neurosecretory system in fish,located in the gill region

Summary A peculiar neurosecretory system is reported in 6 teleost species;Clarias batrachus, Heteropneustes fossilis, Mystus seenghala, Ompak pabda, Glassogobius giuris andNotopterus notopterus. It is located in the gill region close to the pseudobranch or to the carotid labyrinth. The neurosecretory cells have been identified using stains specific for neurosecretion. The results are discussed in the light of the association of the neurosecretory system with the pseudobranch or the carotid labyrinth, and the airbreathing habit of these fishes.We are grateful to Prof. U.S. Srivastava for providing laboratory facilities and for encouragement. The work was financially supported by U.G.C. Research Project grant awarded to C.B.L.S., which is thankfully acknowledged. Thanks are due to M. Seal and Amarlata for technical help rendered.     

Bromothricin

Summary Streptomyces antibioticus (Waksman andWoodruff)Waksman andHenrici 1948, strain Tü 99, produced Bromothricin instead of Chlorothricin, when it was grown in a nutrient medium containing 0.5% potassium bromide. The properties of bromothricin are very close to those of chlorothricin. Its nature was elucidated by degradation to methyl 5-bromo-2-methoxy-6-methylbenzoate.     

Die Reizschwelle der Sinnesorgane als physikalisches Problem

Summary A survey is given of recent work on physical aspects of sensory processes. The reasoning which leads to the generally recognized view that one rod of the retina is excited by only one quantum of light is given in par. II. In par. IIIa summary is given of the papers byHecht andVan der Velden on the number of rods which must be struck in order to obtaina sensation of light. Par. III describes the role of the quantum character of light at higher intensities (de Vries), where it sets a limit to intensity discrimination and visual acuity. The influence of Brownian movement on the process of hearing is discussed in par. VI. It is found that the Brownian movement of the inner ear is close to the threshold actually observed (de Vries), whereas the Brownian motion of the air at the eardrum (seeSivian andWhite) is below the audible threshold. The role of the Brownian movementin the sense cells is described in par. VII; the results are used for an analysis of the mechanism of hearing (see alsode Vries); evidence is obtained that electric voltages are generated in the tectorial membrane (the well-known cochlear microphonics) and that they play an important part in the mechanism of energy transfer to the sense cells (similar voltages were also derived from the cupolæ in the lateral lines of fishes by the present author). Finally some physical arguments are sumarized againstYeagley's theory of bird navigation.     

Attività di neurosecrezione nel sistema nervoso di un Turbellario rabdocelo:Mesostoma lingua (Abildg.)

Summary This investigation is concerned with the neurosecretory activity in the cerebral ganglion of a rhabdocoel turbellarian:Mesostoma lingua (Abildg.).It was observed that the neurosecretory activity is primarily localized in the pear-shaped cells, situated near to the region where the external anterior cords arise from the dorsolateral tract of the cerebral ganglion.The neurosecretory material appears to be transported — via the ventral cords — to the transverse cord behind the pharynx, where it is stored. Then, probably, it flows down into the parenchyma.     

Effect of certain environmental factors on the cerebral neurosecretory cells of American cockroachPeriplaneta americana (L.)

Summary Under illumination, the cerebral neurosecretory cells (NSC) ofPeriplaneta americana were found to be depleted of neurosecretory material (NSM). It is suggested that, due to prolonged exposure to illumination, the synthesis of NSM was checked. The NSC were found densely packed with NSM after keeping the insects in total darkness. Clumping of NSC and their axons was brought about by 15 days of starvation. Diet played no significant role in the neurosecretory activity.We are thankful to Mr Fakhruddin, Saifia Educational Society for providing research facilities.     

Démonstration du caractère géographique de la parthénogénèse deSaga pedo Pallas et de sa polyploïdie,par comparaison avec les espèces bisexuéesS. ephippigera Fisch. etS. gracilipes Uvar

Summary The males of two species of Palestine,Saga ephippigera Fisch. andS. gracilipes Uvar have respectively 33 and 31 chromosomes in the diploid state.S. pedo Pallas, a parthenogenetic thelytoc species largely distributed in Europe, has 68 chromosomes and probably represents a tetraploid. The cells of the three species have identical dimensions and the polyploidS. pedo is even the smallest in size.     

Variations de la différence de potentiel électrochimique des chlorures chezNitella en présence de benzène sulphonate

Summary The chloride electrochemical potential difference between the inside of cells ofNitella translucens and some external solutions, where Cl has been progressively replaced by benzenesulphonate, has been measured by means of Ag-AgCl electrodes. It appears that benzenesulphonate moves into the cell by an electrogenic pump and that the uptake of Cl byNitella is not in contradiction with a carrier hypothesis.

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This work was supported by grants from the F.N.R.S. and was carried out in the Biophysics Section of the Edinburgh University. We are indebted to Dr. E. J.Williams and Dr.Hogg for having sponsored this research and kindly provided the material.     

Eine modifizierte Kapillarmethode zur Messung osmotischer Werte von Pflanzensäften und Lösungen

Summary The capillary method ofBarger for determining molecular weights can also be used for measuring osmotic values of vegetable saps. The method is improved by using capillaries which are closed at one end, siliconcoated inside, and the drops filled in by means of capillary pipettes.     

Metabolism of the neuromodulator d-serine

Over the past years, accumulating evidence has indicated that d-serine is the endogenous ligand for the glycine-modulatory binding site on the NR1 subunit of N-methyl-d-aspartate receptors in various brain areas. d-Serine is synthesized in glial cells and neurons by the pyridoxal-5′ phosphate-dependent enzyme serine racemase, and it is released upon activation of glutamate receptors. The cellular concentration of this novel messenger is regulated by both serine racemase isomerization and elimination reactions, as well as by its selective degradation catalyzed by the flavin adenine dinucleotide-containing flavoenzyme d-amino acid oxidase. Here, we present an overview of the current knowledge of the metabolism of d-serine in human brain at the molecular and cellular levels, with a specific emphasis on the brain localization and regulatory pathways of d-serine, serine racemase, and d-amino acid oxidase. Furthermore, we discuss how d-serine is involved with specific pathological conditions related to N-methyl-d-aspartate receptors over- or down-regulation.     

The lateral neurosecretory cells and mating instinct in maleDysdercus koenigii (Hemiptera: Pyrrhocoridae)

Summary 5 pairs of median and 1 pair of lateral neurosecretory cell groups occur in the protocerebrum of maleDysdercus koenigii, a hemipteran pest on Hibiscus esculentus. The lateral neurosecretory cells (LNSC) are in a state of peak activity when the male engages itself in copulation. 24 h later, the LNSC are found to be inactive, but they again resume their activity 96 h after commencement of copulation. Such males soon start mating if they find another receptive female. It is believed that the secretion of LNSC in maleDysdercus koenigii is responsible for the onset of the urge for mating just as in female insects.     

Bestimmung des DNS-Gehaltes in Zellkernen des Nervengewebes vonHelix pomatia L. undPlanorbarius corneus L. (Stylommatophora und Basommatophora,Gastropoda)

Summary It has been demonstrated by cytophotometric measurements of the DNA-content in glial- and nerve cells of the snailsHelix pomatia (Stylommatophora) andPlanorbarius corneus (Basommatophora) that the giant nuclei of nerve cells in the central ganglia contain more than tens of thousands of DNA compared with sperm nuclei. According to the DNA-content of sperms (=n), the values for glial cells are between 2n and 4n for both species.

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Herrn Prof. Dr. W.Dittrich, Institut für Strahlenbiologie der Universität Münster, danke ich für die Möglichkeit, am UMSP I arbeiten zu dürfen; Frl. A.Stipproweit danke ich für sorgfältige technische Assistenz.     

Suspension culture ofNigella sativa

Summary In suspension culture 91% free cells ofNigella sativa was obtained inWhite's medium supplemented with casein hydrolysate, inositol and adenine. Ploidy distribution pattern was similar in cell clumps of different sizes and free cells. Chromosomal irregularities were more in free cells. A number of globular embryoid were formed when casein hydrolysate, inositol and adenine were added in the medium after subsequent omission of auxin and coconut milk.     

Mast cells in the skin of normal,hairless and athymic mice

Summary The skin of congenitally athymicnu/nu mice is rich in mast cells which stain metachromatically, contain histamine and 5-hydroxytryptamine, and participate in the PCA reaction. Mast cells of athymic mice have thus the attributes of normal mast cells.This work was supported by grants from the Swiss National Science Foundation (No. 3.516.71 and 3.234.74) and the Fritz Hoffmann-La-Roche-Stiftung.The skilful technical assistance of MissR. Keist is gratefully acknowledged.     

J. Zaragosa's centrum minimum,an early version of barycentric geometry

Summary Using the properties of the Centre of Gravity to obtain geometrical results goes back to Archimedes, but the idea of associating weights to points in calculating ratios was introduced by Giovanni Ceva in De lineis rectis se invicem secantibus: statica constructio (Milan, 1678). Four years prior to the publication of Ceva's work, however, another publication, entitled Geometria Magna in Minimis (Toledo, 1674), 2 appeared stating a method similar to Ceva's, but using isomorphic procedures of a geometric nature. The author was a Spanish Jesuit by the name of Joseph Zaragoza.Endeavouring to demonstrate an Apollonius' geometrical locus, Zaragoza conceived his idea of centrum minimum — a point strictly defined in traditional geometrical terms — the properties of which are characteristic of the Centre of Gravity. From this new concept, Zaragoza developed a theory that can be considered an early draft of the barycentric theory that F. Mobius was to establish 150 years later in Der barycentrische Calcul (Leipzig, 1827).Now then, whereas Ceva's work was rediscovered and due credit was given him, to this day Zaragoza's work has remained virtually unnoticed.     

Antiinflammatory reaction associated with murine L1210 leukemia

Summary Mice bearing L1210 leukemia did not show impaired humoral or cellular immune response to antigenic stimulation during the early stage of the tumor, and a depressed response was noted only in the terminal stage. L1210 cells were shown to suppress inflammatory reaction in vivo.Supported in part by USPHS research grant No.5-01-RR05-352-12, and by theIndependent Order of Foresters, San Bernardino District 3208. We acknowledge the valuable assistance ofJudith Johnson andJames Tan in this project. Histopathological examination byDick H. Koobs is appreciated.     

La question des hétérochromosomes chez les Sauropsidés. Oiseaux

Summary The chromosomes of the fowl were studied with the aid ofMakino's andNishimura's water pretreatment squash technique, modified byMatthey, in embryonic spleen and gonads of both sexes. The number of chromosomes was found to be about 78; the numerical variations are to be ascribed to technical difficulties, caused by the extremely small size of the microchromosomes, rather than to an unchromosomelike behaviour of the latter, as was supposed byNewcomer andBrant. As to the exact number of chromosomes, we consider its determination beyond the possibilities of cytology. The 5^th largest pair of the male, represented by a single element in the female, could be identified as the sex chromosome pair, in accordance with the findings ofYamashina. The digamety might be of theZ-O orZ-W type.     

Zur leukotaktischen Wirkung von Aminosäuren in Liquor cerebrospinalis

Summary Intercisternal injections of-aminobutyric acid,l-asparagin,l-glutamine,l-leucine andl-norleucine exert a strong leukotactic action and in dogs result after a short time in a maximum cell increase of 76,000/3 cells.     

Die physikalische Kieme der Wasserinsekten

Summary The air stores carried by a number of aquatic insects have: a) a hydrostatic function (Brocher, Oortwijn-Botjes, Thorpe, andCrisp); b) the function of an oxygen store (Ege, de Ruiter et al.) and c) the function of a physical gill (Strauss-Durckheim, Ege, etc.). The fact that oxygen is taken up from water with the aid of an air bubble was demonstrated forNotonecta by comparing the life time of insects with and without physical gill (while replenishing the oxygen store from the air was prevented) byEge, and forCorixa byPopham, whileVlasblom determined the oxygen uptake from water with and without air bubble forNotonecta, Naucoris, Corixa, Sigara andNepa. Nepa andSigara can take up considerable quantities of oxygen by cutaneous respiration.During the summer, the gill function of the air store ofNotonecta andNaucoris is of importance only when a water current passes along the animal, caused by ventilation movements of the legs (de Ruiter et al.). At low temperatures, however, the metabolic rate is so low that in many instances the physical gill provides the oxygen required without ventilation movements.An apparatus for the simultaneous determination of oxygen uptake from air and water (Wolvekamp andVlasblom) gave results that provided a means of evaluating the importance of the physical gill function.In some cases, the air store, although in direct contact with the water, does not need to be replenished. InAphelocheirus andElmis, the negative pressure in the bubble, caused by oxygen consumption and the diffusing out of part of the nitrogen, is compensated for by the mechanical resistance of a feltwork of thin hairs and the surface tension of the boundary layer of the water (Thorpe andCrisp). In the African beetle,Potamodytes, the unprotected air bubble is permanent because the strong river currents produce a lowered pressure around the animal according toBernoulli's principle (Stride).     

Allatotropic activity of the median neurosecretory cells ofGalleria mellonella (lepidoptera) larval brain

Summary The brain allatotropic hormone (ATTH) is released inGalleria mellonella from the Median neurosecretory cells located in the pars intercerebralis. These cells show the ability to elicit supernumerary larval molts upon implantation into sensitive host larvae, and the ability to in vitro stimulate the juvenile hormone synthesis in corpora cardiaca-corpora allata glands ofG. mellonella.11 November 1986Acknowledgments. I am greatly indebted to Wesleyan University (Connecticut, USA) for supporting this study.