Stinger utilization and predation in the scorpion Paruroctonus boreus

The utilization of the stinger and the predatory technique of the scorpion, Paruroctonus boreus, was studied under laboratory conditions. During the study, 83 feedings were observed. Age of the scorpions and the percentage of prey stung by them were used to classify the scorpions into groups. The scorpions aged 13–61 days always stung prey. After 62 days the scorpions began to selectively utilize the stinger. Utilization declined until it reached 30 percent in the adult stage. The stinger is apparently necessary for prey capture only in the early life stages.       

Microbial spatial heterogeneity in microbiotic crusts in Colorado National Monument. I. Algae

Spatial heterogeneity in visually similar sites under Utah juniper canopy in Colorado National Monument was examined. Sample sites were arranged in a transect 24 m long, such that distances between samples were 0.013 m, 0.03 m, 1.0 m, 12 m, and 24 m. Twenty-five taxa of algae were observed, mostly belonging to Cyanophyta. Algal density varied by more than an order of magnitude within the 46 samples examined. The coefficients of variation for each distance class were very similar, demonstrating that algal patchiness can be as significant on a scale less than 0.013 m as it is on a scale of 24 m. Goodall's random pairing analysis of spatial pattern supported this conclusion by indicating that the minimal area for sampling soil algal crust populations at this site was equal to or less than 0.013 m. Because of the microscale heterogeneity in algal communities in this study, we recommend that future researchers take composite samples if they wish to quantify algae of microbiotic crusts.     

Astrocladistics: A Phylogenetic Analysis of Galaxy Evolution II. Formation and Diversification of Galaxies

This series of papers is intended to evaluate astrocladistics in reconstructing phylogenies of galaxies. The objective of this second paper is to formalize the concept of galaxy formation and to identify the processes of diversification. We show that galaxy diversity can be expected to organize itself in a hierarchy. In order to better understand the role of mergers, we have selected a sample of 43 galaxies from the GALICS database built from simulations with a hybrid model for galaxy formation studies. These simulated galaxies, described by 119 characters and considered as representing still undefined classes, have experienced different numbers of merger events during evolution. Our cladistic analysis yields a robust tree that proves the existence of a hierarchy. Mergers, like interactions (not taken into account in the GALICS simulations), are probably a strong driver for galaxy diversification. Our result shows that mergers participate in a branching type of evolution, but do not seem to play the role of an evolutionary clock.     

A cytogenetic study of a barbary sheep (Ammotragus lervia) x domestic goat (Capra hircus) hybrid

Summary An account is given of stillborn male twins born to a female Saanen goat (Capra hircus) and a Barbary ram (Ammotragus lervia). The cytogenetics of the cultured hybrid cells are described and attention is drawn to the high proportion of cells which lacked one chromosome.Acknowledgment. I. gratefully acknowledge the help of Mr G.E. Embleton who took the skin biopsy of the Barbary ram.     

An evidence for decrease of energy production in thiamine deficient failing rat heart

Résumé La combinaison des substrats — acides pyruvique et fumarique — inhibent le gonflement de mitochondries isolées du coeur de rat, en accord avec le maintien de l'intégrité de la structure mitochondriale par l'adénosine triphosphate produite. On constate la diminution successive de cette inhibition dans des rats déficients en thiamine, par suite du blocage au niveau de la décarboxylation pyruvique. De plus cette carence vitaminique provoque une décroissance graduelle du nombre des mitochondries dans le tissu cardiaque.

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Supported by the Grants H-4012 from the National Heart Institute and K62-3 from the Hospital Division, U.S. Public Health Service. We thank MissV. Meyer for the heart size deteminations.     

Monocyte participation in connective tissue repair

Zusammenfassung Monocyten des strömenden Blutes könnenin vitro die morphologischen und funktionellen (Hydroxyprolinbildung) Kriterien von Fibrocyten erwerben. Die quantitative Bedeutung dieses Phänomens für den reparativen Bindegewebsaufbau wurde mit folgender Versuchsanordnung geprüft: Vergleichbare Inokulate von Monocyten (enthalten in der Leucocytenhaut des zentrifugierten Blutes) und von Fibrocyten (aus subcutanem Bindegewebe) von Kaninchen verschiedenen Geschlechts, wurden in Millipore-Kammern eingeschlossen und für 14–21 Tage in das Abdomen eines Kaninchens implantiert. Die Auszählung des Sex-Chromatins in den fibrocytären Kernen am Ende der Züchtungsperiode ergibt, dass ca. 50% monocytären Ursprunges sind. Es wird gefolgert, dass dieses Phänomen bei der eigentlichen Wundheilung noch bedeutungsvoller sein dürfte, da der Zustrom teilungsfähiger Monocyten in einem Wundgebiet kontinuierlich vor sich geht und nicht auf ein initiales Inokulum beschränkt ist.     

Histochemical comparison of mast cell and globule leucocyte granules in the rat

Zusammenfassung Es werden die Granulationen von Leukozyten, welche im Dünndarm der Ratte infolge einer Helmintiasis auftraten, mit den Granulationen der Mastzellen im s.c. Gewebe verglichen. Die Granulationen in den Mastzellen verhalten sich gegenüber Heparin und Histamin positiv, während die Leukozyten eine negative Reaktion ergeben. Dies weist darauf hin, dass die beiden Zellen nicht identisch sind und wohl aus verschiedener Matrix stammen.