Proleptonchoides southindiae n. gen., n. sp., a New Leptonchoid from South India

Proleptonchoides southindiae n. gen., n. sp. (Dorylaimida: Leptonchidae), is described from soil around false tobacco (Lobelia excelsa) and cardamom (Elettaria cardamomurn) in South India. P. southindiae is prodelphic, has a short constricted esophageal bulb and flanged odontophore, and is phylogenetically close to Proleptonchus.     

Mitochondrial degeneration after organic phosphate poisoning in prosimian primates

Summary The degenerative reaction of mitochondria to tricresylphosphate (TCP) poisoning in spinal ganglion cells of Slow Loris (Nycticebus coucang coucang) were studied with the electron microscope. In neurones of animals treated with TCP, mitochondria display various stages of alterations which confirm mitochondrial involvement in TCP poisoning. The role of degenerated mitochondria in the formation of neuronal lipofuscin is discussed. It is suggested that the lipofuscin granule is a metabolic product inherently related to mitochondrial degeneration, irrespective of the primary cause: ageing or intoxication.Fellow of the Deutscher Akademischer Austauschdienst on study leave from the Medical Faculty, University of SingaporeA grant from the Deutsche Forschungsgemeinschaft (Gl. 28/20) is gratefully acknowledgedThe skilfull technical assistance of Mr. Tajuddin b.M. Ali, Mr. P. Gopal, Mr. R. Dungan and Mrs. C. Weinrichter is gratefully acknowledged     

Synergistic effect of heat-shock and UV-irradiation on mitosis and protein synthesis in G2-phase plasmodia of Physarum polycephalum Schw--reduction in UV-induced mitotic delay in a preheat-shocked system

The synergistic effect of UV irradiation and heat-shock during the last 3 hr of G2 phase of the cell cycle in the plasmodia of P. polycephalum, in terms of mitotic delay and inhibition of protein synthesis, has been evaluated. The mitotic delay due to both perturbers coordinately increased closer to mitosis. Maximum mitotic delay was obtained in plasmodia heat-shocked after UV irradiation, indicating the presence in this system of either a heat-labile mitogenic substance which is comparatively less susceptible to UV or a substance which is made more susceptible to hyperthermia by UV. A protective role for heat-shock applied before irradiation has been observed in that, radiation-induced mitotic delay is significantly reduced in this combination. There was severe inhibition of translation in all the perturbed classes. Organelle level effects which are independent of major protein synthetic activities or different levels of heat-shock protein production could be the reason for the lack of correlation between percentage inhibition of general protein synthesis and the extent of mitotic delay with respect to the two double-perturbed systems.     

Chemical cross-linking study of complex formation between methylamine dehydrogenase and amicyanin from Paracoccus denitrificans

Two soluble periplasmic redox proteins from Paracoccus denitrificans, the quinoprotein methylamine dehydrogenase and the copper protein amicyanin, form a weakly associated complex that is critical to their physiological function in electron transport [Gray, K. A., Davidson, V. L., & Knaff, D. B. (1988) J. Biol. Chem. 263, 13987-13990]. The specific interactions between methylamine dehydrogenase and amicyanin have been studied by using the water-soluble cross-linking agent 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide (EDC). Treatment of methylamine dehydrogenase alone with EDC caused no intermolecular cross-linking but did cause intramolecular cross-linking of this alpha 2 beta 2 oligomeric enzyme. The primary product that was formed contained one large and one small subunit. Methylamine dehydrogenase and amicyanin were covalently cross-linked in the presence of EDC to form at least two distinct species, which were identified by nondenaturing polyacrylamide gel electrophoresis (PAGE). The formation of these cross-linked species was dependent on ionic strength, and the ionic strength dependence was much greater at pH 6.5 than at pH 7.5. The effects of pH and ionic strength were different for the different cross-linked products. SDS-PAGE and Western blot analysis of these cross-linked species indicated that the primary site of interaction for amicyanin was the large subunit of methylamine dehydrogenase and that this association could be stabilized by hydrophobic interactions. In light of these results a scheme is proposed for the interaction of amicyanin with methylamine dehydrogenase that is consistent with previous data on the physical, kinetic, and redox properties of this complex.     

Light microscopic features of the rete testis,the vas efferens,the epididymis and the vas deferens in the adult rhesus monkey

The present study was carried out to determine the detailed histological and cytological features of the excurrent ducts of the male reproductive system in the rhesus monkey. The excurrent ducts show a regional difference in their histological features. The use of some of these features as histological markers and their possible functional significance are discussed. The epithelial cells in the different components of the excurrent duct system possess cytological features which suggest their involvement in absorption and the secretion of different products into the lumen.