Ascorbic acid deficiency and cytochrome P-450 in adult rat hepatocytes in primary monolayer culture.

Adult rat hepatocytes in primary monolayer culture exhibit selective alteration of microsomal constituents and functions during the first hours of incubation ex vivo, including a striking decrease in the concentration of cytochrome P-450. The present studies document that these alterations are due in part to deficiency of l-ascorbate in the cultured cells. The deficiency appears to develop both by loss of the vitamin from the cells during their preparation and by a diminished synthetic capacity for ascorbate. Supplementation of the culture medium with l-ascorbate, at a concentration sufficient to restore intracellular levels of vitamin C to normal, results in maintenance of significantly increased concentrations of cytochromes P-450 and b₅. The activity of NADPH cytochrome c reductase similarly is ascorbate-dependent, suggesting that the vitamin plays a role in the formation and/or stabilization of membrane protein or lipid. Microsomal heme metabolism appeared to be unaffected by the presence or absence of ascorbate.     

Mechanism of action of agents which uncouple oxidative phosphorylation: Direct correlation between protoncarrying and respiratory-releasing properties using rat liver mitochondria

The proton-carrying properties of uncoupling agents were investigated by measuring passive mitochondrial swelling under conditions where electrogenic proton transport was rate limiting. The ability of uncoupling agents to transport protons into mitochondria, measured in this way, was compared with respiratory stimulation. The results show that with the single exception of arsenate, all agents tested which uncouple oxidative phosphorylation demonstrate a very close correlation between release of respiration and proton transport. These findings are in support of Mitchell's original proposal that uncoupling agents act by promoting electrogenic hydrogen ion transport across the mitochondrial inner membrane.     

Evidence for a shift from IgD to IgA synthesis in the maturation of human B lymphocytes.

A case of chronic lymphatic leukemia (CLL) is described in which IgD and IgA are the copredominant membrane immunoglobulins. Since CLL represents malignant proliferations of B lymphocytes arrested at discrete points during maturation, the findings in this case suggest that at least some of the developing cells destined to synthesize IgA for secretion pass through a stage in which immunoglobulins D and A are present together on the cell membrane.     

Augmentation of murine immune responses by amphotericin B.

Immunostimulant effects have been demonstrated in mice following single injections of amphotericin B or amphotericin methyl ester. Augmentation of both humoral and cell-mediated immune responses helps to explain the beneficial therapeutic effects observed in human and murine neoplasms after administration of amphotericin. Relevant to its immunological adjuvant properties, amphotericin produces striking reversible changes in murine thymus and splenic weights and in lymphoid organ histology. The chemical purity, nonimmunogenicity, and permissible toxicity of amphotericin recommend it as a model for the study of the cellular and molecular mechanisms of immunological adjuvants.     

Denatured helical sites and ribonuclease resistant RNA associated with DNA from the dormant seeds of a higher plant

Denatured helical regions in the DNA of dormant cotton seeds were detected by means of ribonuclease interaction, methylated albumin kieselguhr chromatography and sedimentation analysis. Ribonuclease resistant RNA was also found associated with the dormant seed DNA. The implications of these two findings were discussed with regard to possible binding sites for RNA that stabilizes folded DNA.     

Synthesis of type I and type II collagen by embryonic chick cartilage

Embryonic chick articular and keel cartilage was found to synthesize two types of collagen. The amount of Type I collagen synthesis decreased from 60% to nearly 10% during the embryonic period studied, thus suggesting not only coexistence of both collagen types in the same tissue, but also a developmental transformation from predominantly Type I synthesis to Type II synthesis with cartilage development and maturation. Radioautographs suggested that all chondrocytes were equally active in collagen synthesis and failed to show any significant non-cartilagenous tissue contamination. Therefore variation in collagen type synthesis must be a product of some unknown genetic regulatory mechanism within the cartilage tissue.     

Elution of cell-bound anti-prostatic epithelial antibodies after multiple cryotherapy of carcinoma of the prostate

Antibodies reactive with the cytoplasmic membrane or intercellular areas of autologous human and monkey prostatic secretory epithelial cells have been demonstrated by immunofluorescence in an eluate prepared from prostatic tissue obtained from a patient with metastatic adenocarcinoma of the prostate (CaP) after multiple cryotherapy of his primary prostatic tumour. While limited to the study of one patient, elution of anti-prostatic antibodies offers further documentation to previous studies pointing toward the participation of immunologic processes in CaP.     

Serine/Threonine Protein Kinases from Bacteria,Archaea and Eukarya Share a Common Evolutionary Origin Deeply Rooted in the Tree of Life

The main family of serine/threonine/tyrosine protein kinases present in eukarya was defined and described by Hanks et al. in 1988 (Science, 241, 42–52). It was initially believed that these kinases do not exist in bacteria, but extensive genome sequencing revealed their existence in many bacteria. For historical reasons, the term “eukaryotic-type kinases” propagated in the literature to describe bacterial members of this protein family. Here, we argue that this term should be abandoned as a misnomer, and we provide several lines of evidence to support this claim. Our comprehensive phylostratigraphic analysis suggests that Hanks-type kinases present in eukarya, bacteria and archaea all share a common evolutionary origin in the lineage leading to the last universal common ancestor (LUCA). We found no evidence to suggest substantial horizontal transfer of genes encoding Hanks-type kinases from eukarya to bacteria. Moreover, our systematic structural comparison suggests that bacterial Hanks-type kinases resemble their eukaryal counterparts very closely, while their structures appear to be dissimilar from other kinase families of bacterial origin. This indicates that a convergent evolution scenario, by which bacterial kinases could have evolved a kinase domain similar to that of eukaryal Hanks-type kinases, is not very likely. Overall, our results strongly support a monophyletic origin of all Hanks-type kinases, and we therefore propose that this term should be adopted as a universal name for this protein family.     

Communication of gender from human breath odors: Relationship to perceived intensity and pleasantness

During five consecutive daily test sessions, 10 men and women rated the relative intensity and pleasantness of breath odors from 14 males and 19 females on a no-oral-hygiene regimen. In addition, the likely gender of the donor of each odor was also estimated. The breath odors of males were rated, on the average, as more intense and less pleasant than the breath odors of females. Women consistently gave lower pleasantness ratings to the odors than did men. Both the male and female judges assigned the breath odors to the correct gender classes at a frequency unlikely due to chance, although the females were more accurate in this regard. An inverse relation between breath odor intensity and pleasantness was noted. Systematic changes in the rated intensity and pleasantness of the odors were present across the 5 days of the study period. These data suggest that differences exist between the breath odors of men and women, and that humans, like many other mammals, may be capable of assessing gender from oral odors. However, such assignments conceivably reflect the strategy of assigning stronger and less pleasant odors to the male category, and weaker and less unpleasant odors to the female category, regardless of the true sex of the odor donor.