Isolation of a neurosecretory substance which stimulates RNA synthesis in regenerating planarians.

An approach to the isolation of neurosecretory material from planarians is described. This material stimulated RNA synthesis, in a dose-dependent response, in regenerating Dugesia tigrina. The data support the concept that neurosecretion plays a key role in the process of regeneration in planarians.     

The occurrence and physiological functions of melatonin in the most primitive eumetazoans,the planarians

Asexual planarians of the speciesDugesia dorotocephala exhibit a distinct circadian rhythm of fissoning (asexual reproduction) under the influence of normal photoperiod; fissioning occurs only at night. This rhythm is broken down by continuous illumination, continuous darkness or by decapitation. The fissioning rate increases when planarians are exposed to light for less than 1 hour/day or when they are decapitated. Fissioning of decapitated planarians is suppressed by continuous treatment with melatonin, whereas fissioning resumes when these are returned to normal culture water. Interestingly, fissioning occurs at night when decapitates are treated with melatonin in the daytime, while it is observed in the daytime with night-time melatonin treatment. Endogenous melatonin was detected by HPLC and RIA. The endogenous melatonin level is always higher in those heads collected in the scotophase than in those collected in the photophase. A type of neurosecretory cell, which may synthesize melatonin, is found in the assembly of photoreceptor cells.     

Mise en évidence d'un système de corrélations intervenant dans la régénération des Planaires d'eau douce

Summary We show that there are correlations in regenerative fresh water planarians between all the parts of the body. When planarians are wounded in any part of the body, this mutilation will set regenerative cells in movement, which are able to travel a very long way in their migration. The extent and the speed of migration haves been shown by the method of localized X-ray irradiations.When the regenerative cells that are nearest to the wound have been killed with X-rays, regeneration occurs through the access of cells from the farther parts of the body. The nature of the stimulus is not yet known.     

Flavonoids from pollens and stigmas of male and female flowers of four species of the genusCucurbita

Summary Differences have been found between the flavonoid patterns of pollens and corresponding stigmas ofCucurbita pepo, C. maxima, C. moschata andC. ficifolia. The major flavonoids ahve been identified as isorhamnetin-3-O-rutinoside isolated from stigmas ofC. pepo is absent in this material.Acknowledgments. The author thanks Dr Chr. Karl (Weleda, Schwäbisch Gmünd) for a sample of isorhamnetin and Mr A. D'Urso (Botanic Institute, University of Catania) for help in acquiring the plant material.     

Control of the behaviour of leaf-cutting ants by their ‘symbiotic’ fungus

There is an obligatory relationship between leaf-cutting ants of the generaAtta andAcromyrmex (Hymenoptera; Attini) and the fungus,Attamyces bromatificus Kreisel, for which they provide a substrate of cut plant material. We show that the ants learn to reject plant material that contains chemicals injurious to the fungus. After an initial period of acceptance, ants from laboratory nests stopped harvesting granular bait containing a fungicidal agent (cycloheximide) and orange peel. This rejection was maintained for many weeks. These colonies also rejected control bait containing no cycloheximide. Some generalisation of the response was observed; colonies rejecting orange granules also rejected grapefruit granules, although they still accepted blackcurrant granules. Rejection of fungicidal bait by colonies in the field was restricted to ants on foraging trails exposed to experimental bait. We conclude that a semiochemical from the fungus, circulated by trophallaxis and grooming, regulates the selection of plant material by foragers. The fungus gains more advantages from the symbiotic relationship than is often realised. The ants provide the fungus with housing, sanitation, defence against disease and predators, pre-selected food, and a means of dissemination, at the cost to itself of providing food for the ant brood.     

Vitellogenesis in the air breathing fish,Channa punctatus (Bloch)

Summary Two types of yolk develop in the oocyte ofChanna punctatus. The carbohydrate yolk, which develops from the material present in the ooplasm, breaks up for the use of the growing oocyte before ovulation takes place. The proteid yolk, developing from the extraoocytic material, finally crams the fully mature oocyte, perhaps to participate in the process of embryogenesis.Acknowledgments. The authors are grateful to Professor C.C. Das, for his encouragement and the laboratory facilities. The award of a U.G.C. junior fellowship to one of us (U.R.A.) by the Berhampur University is thankfully acknowledged.     

Protoporphyrin und Hämin in Kulturfiltraten vonAchromobacter metalcaligenes

Summary A macromolecular fraction from the culture fluid ofAchromobacter metalcaligenes showing the activity of the Haemophilus-X factor was investigated for its content of porphyrin derivatives. Porphyrin methylesters were directly prepared from the lyophilized material and then separated by thin layer chromatography. Protoporphyrin and iron protoporphyrin could be isolated in amounts which correlated with the growth-promoting activity forHaemophilus influenzae.     

Photodecomposition of orellanine and orellinine,the fungal toxins ofCortinarius orellanus Fries andCortinarius speciossimus

Summary The photosensitivity of orellanine, the main toxin ofCortinarius orellanus Fries mushrooms, and its transformation to orelline via orellinine is discussed. All three substances were found in methanolic extracts ofCortinarius orellanus andCortinarius speciossimus mushrooms. The problem of homogeneity of orellanine is also discussed.Acknowledgment. The authors wish to express their gratitude to Prof. Dr W. Steglich from the Institut für Organische Chemie und Biochemie der Universität Bonn (Federal Republic of Germany) for having provided them with a sample of dried material ofC. speciossisimus.     

Mögliche Beziehungen der optischen Aktivität zum Problem des Alterns

Summary The solubilities and other properties of compounds made by combination of optically active components, e.g. the solubilities of the salts made from the dextro-form of an acid and the dextro- or the laevo-form of a base are in some instancesextremely different. It is a consequence of these differences that in a living organism, containing optically active substance,the degree of optical purity of these substances is of outmost importance. The presence of undesired antipodes of any kind might fundamentally disturb the metabolism. It is also known that living organisms at least partly and continuously produce the optically active substances needed bysynthesis from optically inactive material.A kinetical and thermodynamical study of the conditions under which optically active substances can, with use of optically active catalysers, be synthetized from inactive material, shows that the degree of optical purity of the material synthetized is, even under the most favorable conditions, maximum in the beginning of the synthesis andis bound to decay when the synthesis is, chemically speaking,completed and if the synthetized material is left in contact with the catalyzer. Thus a racemization of the synthetized active material occurs in which the catalyzer which has originally produced this active substance actively accelerates the deterioration of its state of optical purity.The means are discussed by which the organism is able to delay this loss of optical purity; and it is shown that all poosible means to do so are indeed used by the organism. As these means can delay but never completely avoid the decay of optical purity, this decay, even if it be slow, i.e.an ageing of optical purity, is a necessity in the course of the life of a living organism. As a loss of optical purity must disturb the normal metabolism, this must, even if no other events occur, limit the individual life.Experimental evidence which would check the prediction of decay of optical purity with age is incomplete; in several instances, however, the experimental technique permits us to detect and to follow the occurrence of finite small amounts of undesired antipodes, e.g. of some amino acids in the proteins of living organisms.

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Vortrag, gehalten vor der Schweizerischen Gerontologischen Gesellschaft in Basel am 11. Dezember 1954.     

The ultrastructure of the spiral notosetae ofNicomache maculata Arwidsson (Polychaeta,Maldanidae)

Summary Scanning- and transmission electron microscopy show that the long, thin notosetae ofNicomache maculata are helical over much of their length, and that their finely feathered appearance is produced by a series of minutely spiny scales. The internal structure varies considerably from one end of the seta to the other. While a helical shape could result from a rotating or asymmetrical secretion-rate gradient across the chaetoblast, we raise the possibility that the spiral represents a warp in the seta following deposition of the setal material.     

A crystalline,toxic, peptide metabolite ofTrichoderma spp. isolated from soil

Summary Isolates ofTrichoderma spp. from pasture soils of Nova Scotia produce at least 7 toxic peptides, probably related to alamethicin, some of which inhibit the growth of cellulase producing rumen bacteria. One of the peptides has been obtained in crystalline form and crystal data on this material is reported.     

Sequential analysis of Giemsa banded chromosomes inVicia faba

Summary Vicia faba (broad bean) root-tip chromosomes were subjected to the SSC-Giemsa and trypsin-Giemsa regimes. Phase-lucent cross-bands seen after fixation/SSC treatment subsequently stain positively with Giemsa. Sequential analysis of the trypsin-Giemsa regime shows, in contrast, that bands are manifest through selective removal of material from interband regions.     

The potency of male accessory gland material in the mosquito (Aedes aegypti)

Summary Injections of male accessory gland material fromAedes aegypti into the hemocoeles of virgin female mosquitoes indicate that the potency of the secretion is equivalent to the amount of semen which a male normally places within the female. This estimation is far less than had been previously calculated. It is suggested that the termmatrone for male accessory gland material is inappropriate since it does not convert a maid into a matron but prevents reinsemination of an impregnated female.Scientific Article No. A2098, Contribution No. 5054 of the Maryland Agricultural Experiment Station.     

Isolation from rat brain of a metabolic product,desmethylimipramine, that mediates the antidepressant activity of imipramine (Tofranil)

Zusammenfassung Nach Verabreichung von Imipramin (Tofranil) wurde aus dem Gehirn von Ratten Desmethylimipramin, das N-Monomethylderivat, isoliert. Dieser Metabolit beziehungsweise dessen Anreicherungin vivo scheint für die antidepressive Wirkung von Imipramin verantwortlich zu sein.

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Presented in part as an abstract in Fed. Proc.20, 321 (1961). Some of the material in this communication is taken from a dissertation byJ. V. Dingell to be submitted to the Graduate School of Georgetown University in partial fulfillment of the requirements for the degree of Doctor of Philosophy.     

Between meaning culture and presence effects: contemporary biomedical objects as a challenge to museums

The acquisition and display of material artefacts is the raison d’être of museums. But what constitutes a museum artefact? Contemporary medicine (biomedicine) is increasingly producing artefacts that do not fit the traditional museological understanding of what constitutes a material, tangible artefact. Museums today are therefore caught in a paradox. On the one hand, medical science and technologies are having an increasing pervasive impact on the way contemporary life is lived and understood and is therefore a central part of the contemporary world. On the other hand, the objects involved in medical diagnostics and therapies are becoming increasingly invisible and intangible and therefore seem to have no role to play as artefacts in a museum context. Consequently, museums are at risk of becoming alienated from an increasingly important part of contemporary society. This essay elaborates the paradox by employing Gumbrecht’s (2004) distinction between ‘presence’ and ‘meaning’.     

Effect of the polychlorinated biphenyl preparation,Aroclor 1242, on the quantity of neurosecretory material in the medulla terminalis X-organ of the fiddler crab,Uca pugilator

Summary Exposure of the fiddler crab,Uca pugilator, to the PCB preparation, Aroclor 1242, produces an increase in the quantity of neurosecretory material in the medulla terminalis X-organ. This Aroclor apparently inhibits release, but not synthesis, of one or more neurohormones.This investigation was supported by grant PCM75-03029 A01 from the National Science Foundation.     

Chromatin organization within nuclear blebs in leukocytes ofXenopus laevis

Summary The nuclei from leukocytes of peripheral blood, liver and spleen of an individual anaemicXenopus laevis have been found to possess numerous nuclear blebs or projections. These structures were found to be very variable in size and shape as viewed in electron micrographs, but commonly included an enclosed mass of cytoplasm bound on one side by a very thin section of nuclear material. Such sections are membrane bounded on each side and frequently display an interesting ordered array of chromatin.     

Dictyostelium discoideum cells shed vesicles with associated DNA and vital stain Hoechst 33342

Dictyostelium discoideum cells are highly resis tant to xenobiotics. We previously observed that these primitive eukaryotic cells contain a 170-kDa P-glycoprotein, mediating multidrug resistance in mammalian cells, but nonfunctional in Dictyostelium cells. We show here that D. discoideum cells vitally stained with the DNA-specific dye, Hoechst 33342, release fluorescent material in their culture medium. Electron microscopy and lipid analysis demonstrate the vesicular nature of this material. Moreover, nucleic acids associate with these extracellular vesicles independently of Hoechst vital staining. The main vesicular DNA component exhibits a size >21 kb. Shedding of microvesicles during cell growth is not concomitant with programmed cell death. We propose that these extracellular vesicles are involved in a new cellular resistance mechanism against xenobiotics. Furthermore, since the association of DNA with vesicles occurs in physiological growth conditions and independently of vital staining, the new shedding process might be involved in a more general intercellular mechanism. Received 14 November 1997; received after revision 16 March 1998; accepted 16 March 1998     

Histone bei dem PhycomycetenAllomyces arbuscula (Butl.)

Summary Electrophoresis on acrylamide gel of basic proteins from the fungusAllomyces arbuscula (Butl.) yielded at least 16 bands. No differences were found between the banding-patterns of sporophyte and gametophyte. Extraction of histones from 1000 mg lyophilized mycelium and subsequent electrophoresis produced no bands. If histones are present at all, their concentration must be extremely low (< 5 µg/1000 mg material).