Life v2.0 - Quo vadis Homo sapiens ?

This editorial briefly discusses the implications of the recent report by Craig Venter et al. on re-creating Mycoplasma mycoides as a synthetic life form.     

Growth hormone control of glucose oxidation pathways in hypophysectomized rats.

An in vivo response of glucose oxidation to growth hormone has been demonstrated. Hypophysectomized rats were found to oxidize glucose at rates significantly higher than normal rats. Treatment with growth hormone 1 h before injection of 14C-U-glucose, 14C-6-glucose, or 14C-1-glucose caused a return to a normal oxidation pattern. This acute response was independent of insulin action but clearly time-dependent since no change from untreated hypophysectomized rats appeared when growth hormone was given at various times prior to administration of labeled glucose. The response observed for 14C-6-glucose was comparable to that observed for 14C-1-glucose with regard to dynamics but differed with respect to total 14C recovered as 14CO2. The cumulative percent 14CO2 recovered from oxidation of 14C-6-glucose 1 h after growth hormone injection exceeded that recovered from oxidation of 14C-1-glucose. These results suggest a change in glucose oxidation by a route that cannot be explained solely by changes in either the hexose monophosphate or Embden-Meyerhof pathways.     

Persistence of Allegheny woodrats Neotoma magister across the mid-Atlantic Appalachian Highlands landscape, USA

We examined a suite of macro-habitat and landscape variables around active and inactive Allegheny woodrat Neotoma magister colony sites in the Appalachian Mountains of the mid-Atlantic Highlands of Maryland, Virginia, and West Virginia using an information-theoretic modeling approach. Logistic regression analyses suggested that Allegheny woodrat presence was related positively to distance to the nearest occupied colony site and was influenced by location within physiographic subprovince. Colony sites were more likely to be active to the west (Allegheny Plateau) than the east (Blue Ridge/Piedmont), and colony sites were less likely to be active north of the Potomac River where land use and human disturbance patterns in the region were more intensive. Support also was generated for a presence-absence model that included forest cover within a 1-km radius of colony sites, although its importance was equivocal in this heavily forested region. Allegheny woodrats rely on emergent rock habitats for denning, and mast-bearing forest communities for foraging, and appear to display a metapopulation structure that is sensitive to a combination of natural and anthropogenically-induced isolation pressures that are recognizable but difficult to manage or mitigate.     

Pre- and post-embedding immunoelectron microscopy of Ki-M1P immunoreactive germinal center macrophages using ultra-small gold probes with silver enhancement

The Ki-M1P protein is primarily detected in cells deriving from the monocyte/macrophage cell lineage. The aim of this study was to investigate the occurrence of Ki-M1P immunoreactivity in germinal center macrophages by immunohistochemical and immunocytochemical staining techniques. Ultra-small (0.8 nm) gold probes combined with silver enhancement were used as a detection system for pre- and post-embedding immunostaining both at the light and electron microscopic level. Ki-M1P-positive macrophages were observed at a constant frequency in the germinal centers of the follicles throughout the tonsillar lymphatic tissue. The specific immunostaining was localized in the cytoplasm of these cells. Electron microscopic examination demonstrated the presence of abundant lysosomes in the cytoplasm, and some of the germinal center macrophages contained phagocytosed cells (tingible bodies) showing signs of various degrees of digestion. Ki-M1P immunoreactivity, as revealed by depositions of silver-enhanced ultra-small gold probes, was confined to the periphery of the lysosomes and tingible bodies. The results obtained demonstrate that the use of silver-enhanced ultra-small gold probes is a highly sensitive and specific detection system for pre- and post-embedding immunostaining of the Ki-M1P protein, and provides, in general, a flexible system for combined light and electron microscopic examination of tissue antigens. Furthermore, in the cytoplasm of the germinal center macrophages a spatial association between the Ki-M1P protein and lysosomes and tingible bodies was observed. These findings may indicate that the Ki-M1P protein is connected with phagocytosis and/or processes related to intracellular digestion in these cells.     

Dietary immunoassay of pelagic nemerteans by use of cross-reacting polyclonal antibodies: preliminary findings

With little data on the diet of pelagic nemerteans, apreliminary immunoassay survey of the gut contents ofthree species from the Pacific Ocean was performedusing non-specific, cross-reacting polyclonalantibodies. Results suggest that Nectonemertescf. mirabilis, Phallonemertes cf. murrayi, and Cuneonemertes elongata containedsomewhat different types of prey. Worms elicitedstrong responses when probed with antibodies tosquid-like mollusks and to mysids and shrimp. Heteropods are more likely ingested than pteropods. Additional studies must be done to confirm thesehighly suggestive results.     

Requirements for the light-stimulated degradation of stromal proteins in isolated pea (Pisum sativum L.) chloroplasts

Chloroplasts from 17-d-old pea leaves (Pisum sativum L.) wereisolated to elucidate the requirements for the light-induceddegradation of stromal proteins. The influence of electron transportthrough the thylakoids and the influence of ATP on protein degradationwere investigated. When chloroplasts were incubated in the light(45 µmol m^–2s^–1), glutamine synthetase, thelarge subunit of ribulose-1,5-bisphosphate carboxylase and glutamatesynthase were degraded, whereas phosphoribulokinase, ferredoxin-NADP⁺reductase and the 33 kDa protein of photosystem II remainedmore stable. Major protein degradation was not observed over240 mm in darkness. The electron transport inhibitor dichlorophenyldimethylureareduced protein degradation in the light over several hours,whereas dibromothymoquinone was less effective. Inhibiting theproduction of ATP with tentoxin or by destroying the