Phosphorylation of ribosomal proteins in hamster fibroblasts infected with pseudorabies virus or herpes simplex virus.

In BHK cells infected with pseudorabies virus, there was a substantial increase in the phosphorylation of ribosomal protein S6. This increase occurred between 2 and 4 h after infection and persisted at least until 9 h. We estimated that in mock-infected cells S6 contained, on an average, one phosphate group per protein chain, whereas in infected cells this rose to between four and five phosphate groups per protein chain. A second ribosomal protein, either S16 or S18, was also phosphorylated after infection. No increase in cyclic AMP was found at the time of phosphorylation. We also found an increased phosphorylation of S6 in herpes simplex virus-infected BHK cells.     

Increase in activity of glucose 6-phosphate dehydrogenase in mouse mammary tissue cultured with insulin

1. In organ cultures of mammary tissue from C3H mice we observed increases in the activity of glucose 6-phosphate dehydrogenase similar to that occurring at parturition. 2. In 22hr. cultures of tissue from late-pregnant mice insulin was required for the increases, but the further addition of prolactin, corticosterone and certain other hormones had no effect. The rise in activity occurred over the second half of the culture period. 3. Results from culture of adipose tissue, and mammary tissue rich in adipose tissue, strongly suggest that the rise in activity occurs in mammary parenchymal rather than adipose cells. 4. In 45hr. cultures prolactin prevented a fall in enzyme activity between 22hr. and 45hr. If the medium contained serum the activity at 22hr. was unaffected, but it continued to rise up to 45hr., and prolactin then had no effect. 5. The enzyme also increased in activity in cultures of mammary tissue from mid-pregnant mice. Insulin was again required, the activity was higher at 45hr. than at 24hr. and prolactin increased the activities at both these times. 6. Actinomycin D, cycloheximide and puromycin at low concentration in the media of 22hr. cultures all prevented increases in enzyme activity. Hydroxyurea at a concentration that inhibited the incorporation of [(3)H]thymidine into DNA by 92% had little effect. 7. Actinomycin D and cycloheximide largely failed to prevent the rise in enzyme activity if added after 3.5hr. and 12hr. respectively. Hence all essential RNA and protein synthesis appears to be finished by 3.5hr. and 12hr., although most of the increase in enzyme activity occurs gradually between 12hr. and 22hr. 8. We suggest that the increases in enzyme activity, both in culture and in the living animal at parturition, are induced by an influx of glucose that is restrained during pregnancy by the growth-hormone-like action of placental lactogen.     

Molecular evolution of rodent insulins

Several trees of amino acid sequences of rodent insulins were derived with the maximum-parsimony procedure. Possible orthologous and paralogous relationships were investigated. Except for a recent gene duplication in the ancestor of rat and mouse, there are no strong arguments for other paralogous relationships. Therefore, a tree in agreement with other biological data is the most reasonable one. According to this tree, the capacity to form zinc-binding hexamers was lost once in the ancestor of the hystricomorph rodents, followed by moderately increased evolutionary rates in the lineages to African porcupine and chinchilla but highly increased rates in at least three independent lines to other taxa of this suborder: guinea pig, cuis, and Octodontoidea (coypu and casiragua).      

Motivated Proteins: A web application for studying small three-dimensional protein motifs

Background  

Small loop-shaped motifs are common constituents of the three-dimensional structure of proteins. Typically they comprise between three and seven amino acid residues, and are defined by a combination of dihedral angles and hydrogen bonding partners. The most abundant of these are αβ-motifs, asx-motifs, asx-turns, β-bulges, β-bulge loops, β-turns, nests, niches, Schellmann loops, ST-motifs, ST-staples and ST-turns.     

Changes in fluid secretion rate alter net transepithelial transport of MRP2 and P-glycoprotein substrates in Malpighian tubules of Drosophila melanogaster

The effects of stimulants of fluid secretion on net transepithelial transport of the MRP2 substrate Texas Red and the p-glycoprotein substrate daunorubicin were examined in Malpighian tubules of Drosophila melanogaster. Fluid secretion rates were determined using the Ramsay assay and secreted fluid concentrations of Texas Red and daunorubicin were determined using a microfluorometric technique. Nanoliter droplets of secreted fluid were collected in optically flat glass capillaries and dye concentration was determined from fluorescence intensity measured by confocal laser scanning microscopy. Net transepithelial flux of each compound was then calculated as the product of its concentration in the secreted fluid and the fluid secretion rate. Net transepithelial flux of Texas Red increased when fluid secretion was stimulated by tyramine, cyclic AMP or hypoosmotic saline. Net flux decreased when fluid secretion rate of cAMP-stimulated tubules was reduced by elevating saline osmolality with sucrose. Net transepithelial flux of daunorubicin increased when fluid secretion was stimulated by cAMP. Significant increases in dye flux were seen only when the dyes were present at concentrations close to or greater than the concentration required for half maximal transport. Regression analyses showed that 57- 88% of the change in dye flux was attributable to the change in fluid secretion rate when tubules were stimulated with cAMP, cGMP, or tyramine. The results do not suggest that the effects of tyramine and cAMP are mediated through changes in transepithelial potential, nor do they indicate the direct effects of the stimulants on MRP2-like or p-glycoprotein-like transporters (e.g., via protein kinases). Instead, the results suggest that increases in fluid secretion rate minimize diffusive backflux of these dyes and, thus, facilitate higher rates of net transepithelial transport indirectly.     

The Influence of Radiographic Phenotype and Smoking Status on Peripheral Blood Biomarker Patterns in Chronic Obstructive Pulmonary Disease

Background

Chronic obstructive pulmonary disease (COPD) is characterized by both airway remodeling and parenchymal destruction. The identification of unique biomarker patterns associated with airway dominant versus parenchymal dominant patterns would support the existence of unique phenotypes representing independent biologic processes. A cross-sectional study was performed to examine the association of serum biomarkers with radiographic airway and parenchymal phenotypes of COPD.

Methodology/Principal Findings

Serum from 234 subjects enrolled in a CT screening cohort was analyzed for 33 cytokines and growth factors using a multiplex protein array. The association of serum markers with forced expiratory volume in one second percent predicted (FEV1%) and quantitative CT measurements of airway thickening and emphysema was assessed with and without stratification for current smoking status. Significant associations were found with several serum inflammatory proteins and measurements of FEV1%, airway thickening, and parenchymal emphysema independent of smoking status. The association of select analytes with airway thickening and emphysema was independent of FEV1%. Furthermore, the relationship between other inflammatory markers and measurements of physiologic obstruction or airway thickening was dependent on current smoking status.

Conclusions/Significance

Airway and parenchymal phenotypes of COPD are associated with unique systemic serum biomarker profiles. Serum biomarker patterns may provide a more precise classification of the COPD syndrome, provide insights into disease pathogenesis and identify targets for novel patient-specific biological therapies.