The p lambda CM system: phage immunity-specific incompatibility with IncP-1 plasmids

Summary A pCM2 replicon derived by an N^– deletion from ::Tn9 which carries the imm434 immunity region is incompatible with some (but not all) IncP-1 plasmids. The imm pCM1 replicon does not show the same incompatibility behavior.     

Microbial populations in wetwood of European white fir (Abies alba Mill.)

Abstract A method for extraction of microbial populations from wood samples was worked out which gave good recovery of both aerobic and anaerobic microorganisms in agar shake dilution and plating enumerations. This method was applied to the quantification of microbial populations in three European white firs ( Abies alba Mill.) which were afflicted with the European fir disease. Low numbers of aerobic microorganisms (10²−10⁴ colony- forming units (cfu) per g fresh tissue) were detected in sapwood irrespective of the degree of affliction. Anaerobic bacteria were usually 1–2 orders of magnitude less frequent. Wetwood of highly diseased firs contained significantly higher numbers of aerobic microorganisms (10⁵−10⁷), whereas the number of anaerobes was not enhanced significantly. Among the prevalent aerobic microorganisms in wetwood were Protaminobacter, Pseudomonas strains, and a yeast. In anaerobic counts from wetwood, Klebsiella and Vibrio strains predominated. The sapwood contained Bacillus, Beijerinckia, Staphylococcus , and Clostridium spp. High numbers of aerobic microorganisms were also detected in the roots and lower stem of a diseased vine plant ( Vitis vinifera L.). The importance of microbial populations in wetwood formation and disease expression is discussed.     

Ethnogenesis of South Asia with special reference to India

An attempt has been made to illustrate the quite complicated process of ethnogenesis in South Asia from the viewpoint of physical anthropology. The numerous invading waves which reached the Indian subcontinent from the northwest played an important role in this process. Most important for the ethnogenesis of South Asia was the invasion of Indo-Aryan groups in the middle of the 2nd millenium B.C. known from historical sources. In large parts of the Indo-Pakistan region they assimilated the aboriginal population in ethnic, cultural and linguistic respects in the course of time. Furthermore, the ethnogenesis of the Indian region is determined by the caste system of Hinduism which, however, is not as rigid as generally assumed. There are numerous evidences that since more than 2000 years a slow but steady process of assimilation and integration of tribal groups, living in the forest areas of Central India, into the Hindu caste system took place, a process which is still going on. It is intended to demonstrate to what degree the ethnogenetic processes in South Asia, known from prehistoric and historical sources, can be traced in human skeletal findings of different time periods as well as in the anthropological structure of the living population. Finally, hypotheses and theories, especially those of Risley and von Eickstedt are discussed, who attempted to interpret the great variability of anthropological and morphological traits in the Indian subcontinent by taking into consideration the existence of different old population substrata and their mixing and assimilation.     

The effects of microtubule dissociating agents on the physiology and cytology of the sensory neuron in the femoral tactile spine of the cockroach, periplaneta americana L

Microtubules are prominent cellular components of the mechanosensory and chemosensory sensilla associated with the insect cuticle, and a range of hypotheses have been proposed to account for their role in sensory transduction. Chemical agents such as colchicine and vinblastine, which dissociate microtubules, also interfere with transduction in these sensilla, and this has been attributed to their anti-microtubule activity. We have now examined the dynamic properties of sensory transduction in the mechanosensitive neuron of the cockroach femoral tactile spine, after the application of colchicine, vinblastine and lumicolchicine. Concurrently we have examined the ultrastructure of the same sensory ending by transmission electron microscopy. All of the drugs reduced the mechanical sensitivity o the receptor. Colchicine and vinblastine achieved this reduction without altering the dynamic properties of the receptor but lumicolchicine changed the dynamic response, and increased the relative sensitivity to rapid movements. Conduction velocity, another measure of neuronal function, which relies upon ionic currents flowing through the membrane, was reduced by all three drugs. The effects of the drugs upon the ultrastructure of the sensory ending were also disparate. In the case of colchicine there was complete dissociation of microtubules in the tubular body and distal dendrite before a total loss of mechanical sensitivity. Vinblastine was less effective in dissociating microtubules, although more effective in the reduction of mechanical sensitivity. With lumicolchicine the dominant morphological effect was a severe disruption of the dendritic membrane. We conclude from these experiments that microtubules are not essential in the transduction of mechanical stimuli by cuticular receptors and that the effects of these drugs upon mechanosensitivity are not directly related to their dissociation of the microtubules in the tubular body, but are more likely to arise from actions upon the cell membrane. These actions could include effects upon tubulin in the membrane or upon other membrane components.     

Alterations in lymphocyte homing patterns within mice exposed to ultraviolet radiation

This report presents the results of an investigation designed to establish whether exposure of mice to ultraviolet radiation (UVR) is capable of influencing the factors that control the distribution of lymphoid cells in vivo. We found that such exposure resulted in a dramatic and long-lasting increase in the tropism of peripheral lymph nodes for circulating lymphoid cells. Termination of UVR exposure did not result in a reversal of this phenomenon. Since an increase in lymphocyte migration into the lymph nodes of UVR-exposed mice was apparent within 2 hr of infusion of the radiolabeled cells, we conclude that the homing assay data reflect a relatively increased binding of circulating lymphocytes to high endothelial venules (HEV) within the lymph nodes of irradiated animals. A histologic analysis of skin from UVR-exposed mice established that the dermal microvasculature had expanded in terms of size and number of vessels, a condition that also does not completely reverse after the termination of treatments. In spite of the increase in dermal microvasculature, very few inflammatory cells were detected in the irradiated skin site. These observations support our conclusion that the enhanced traffic of lymphocytes into peripheral lymph nodes of UVR-exposed mice occurs primarily via lymphocyte-HEV interactions rather than afferent drainage of the irradiated skin.     

Stephanoscyphus Allman (Scyphozoa Coronatae), ein rezenter Vertreter der Conulata?

The scyphopolypStephanoscyphus Allman 1874 represents the polyp generation of the scyphomedusan order Coronatae. The benthonic polyp is known to occur with several species on the continental shelves and in greater depths of the oceans. Participating in the International Indian Ocean Expedition 1964 to 1965 on board of the German research vessel «Meteor», the author was able to collect living specimens. For the first time, it was possible to rear these polyps in laboratory cultures.Stephanoscyphus differs from all other living scyphopolyps by the possession of a firm periderm tube enclosing completely the soft body. It is this primitive feature whichStephanoscyphus has in common with the Conulata being the ancestors of the recent Scyphozoa. The characteristics found in a detailed investigation of the periderm tube ofStephanoscyphus conform well with those found in the tubes of the Conulata except for the closure of the aperture by triangular flaps which are absent inStephanoscyphus. The soft body contains primitive features as well. Hence from the existence, morphology and life history it must be concluded that the type of organization which the Conulata exhibited has survived inStephanoscyphus.     

Stephanoscyphus (Scyphozoa,Coronatae) und seine direkte Abstammung von den fossilen Conulata

The scyphopolypStephanoscyphus Allman 1874 represents the polyp generation of the scyphomedusan order Coronatae. Though this polyp has been known for more than a hundred years its general morphology, systematics, and evolution have been inadequately described. Participating in the International Indian Ocean Expedition, 1964 to 1965, on board of the German research vessel “Meteor”, the author was able to collect a sufficient supply of livingStephanoscyphus off the coasts of South Arabia and East Africa. For the first time, it was possible to rear these polyps in laboratory cultures. A thorough investigation of morphology, developmental history and behaviour based on longterm observations of the living polyps gave clear indications thatStephanoscyphus directly descended from the fossil group of Conulata, the scyphozoan nature of which has been affirmed byKiderlen (1937) andKnight (1937). The main feature whichStephanoscyphus has in common with the Conulata is the possession of a periderm tube. The characteristics found in a detailed investigation of the periderm tube conform well with those found in the periderm of the Conulata except for the closure of the aperture by triangular flaps which are absent inStephanoscyphus. The soft body contains primitive features as well. Hence it must be concluded finally that the type of organization which the fossil ancestors exhibited has survived inStephanoscyphus and that the Coronatae represent the most basic group of all living Scyphozoa. On the other hand, the results give strong support for the scyphozoan nature of the Conulata, the organization and life history of which have been elucidated by the observations of the living representatives ofStephanoscyphus.