Cytokine regulation of facilitated glucose transport in human articular chondrocytes.

Glucose serves as the major energy substrate and the main precursor for the synthesis of glycosaminoglycans in chondrocytes. Facilitated glucose transport represents the first rate-limiting step in glucose metabolism. This study examines molecular regulation of facilitated glucose transport in normal human articular chondrocytes by proinflammatory cytokines. IL-1beta and TNF-alpha, and to a lesser degree IL-6, accelerate facilitated glucose transport as measured by [(3)H]2-deoxyglucose uptake. IL-1beta induces an increased expression of glucose transporter (GLUT) 1 mRNA and protein, and GLUT9 mRNA. GLUT3 and GLUT8 mRNA are constitutively expressed in chondrocytes and are not regulated by IL-1beta. GLUT2 and GLUT4 mRNA are not detected in chondrocytes. IL-1beta stimulates GLUT1 protein glycosylation and plasma membrane incorporation. IL-1beta regulation of glucose transport in chondrocytes depends on protein kinase C and p38 signal transduction pathways, and does not require phosphoinositide 3-kinase, extracellular signal-related kinase, or c-Jun N-terminal kinase activation. IL-1beta-accelerated glucose transport in chondrocytes is not mediated by endogenous NO or eicosanoids. These results demonstrate that stimulation of glucose transport represents a component of the chondrocyte response to IL-1beta. Two classes of GLUTs are identified in chondrocytes, constitutively expressed GLUT3 and GLUT8, and the inducible GLUT1 and GLUT9.     

Human body odour, symmetry and attractiveness.

Several studies have found body and facial symmetry as well as attractiveness to be human mate choice criteria. These characteristics are presumed to signal developmental stability. Human body odour has been shown to influence female mate choice depending on the immune system, but the question of whether smell could signal general mate quality, as do other cues, was not addressed in previous studies. We compared ratings of body odour, attractiveness, and measurements of facial and body asymmetry of 16 male and 19 female subjects. Subjects wore a T-shirt for three consecutive nights under controlled conditions. Opposite-sex raters judged the odour of the T-shirts and another group evaluated portraits of the subjects for attractiveness. We measured seven bilateral traits of the subject's body to assess body asymmetry. Facial asymmetry was examined by distance measurements of portrait photographs. The results showed a significant positive correlation between facial attractiveness and sexiness of body odour for female subjects. We found positive relationships between body odour and attractiveness and negative ones between smell and body asymmetry for males only if female odour raters were in the most fertile phase of their menstrual cycle. The outcomes are discussed in the light of different male and female reproductive strategies.     

Topography strongly affects atmospheric deposition and canopy exchange processes in different types of wet lowland rainforest,Southwest Costa Rica

Bulk precipitation and throughfall were collected in a wet lowland rainforest in SW Costa Rica on an event basis to allow modelling the contributions of dry deposition and canopy exchange to nutrient inputs and internal cycling of nutrients. Estimates based on bulk precipitation underestimated total atmospheric deposition to tropical rainforests by up to 10-fold ignoring the contributions of dry deposition. Canopy exchange contributed most of the aboveground inputs to the forest soil of Na⁺, about half for K⁺, 10% for P and Mg²⁺ and negligible for N, C and other elements. Tree species composition did not account for the differences found in net throughfall between forest sites, and vegetation structure (plant area index) had only a small effect on net throughfall. Forest regrowth affected net throughfall through reduced soil fertility and differences in leaf traits. Topography most significantly affected net throughfall via increased dry deposition at sites of higher elevation and via soil fertility and increased canopy exchange at down slope sites.     

Effect of treatment of soil with keratinaceous material on thermophilic fungi

Fusarium oxysporum f. sp. lycopersici and Rhizoctonal solani were grown in a complete 1.0 mM nutrient solution, and in solutions where Ca, Fe, K, Mg, N, P, and S were either excluded (0.0 mM) or included at depleted levels (0.1 mM) while all other constituents were maintained at 1.0 mM levels. Dry weight of both fungi were determined. For both fungi some of the lowest dry weights were recorded for samples grown in the complete solution. Exclusion of K, Mg, and S significantly increased dry weight of Fusarium. Inclusion at the 0.1 mM level of most components significantly increased Fusarium dry weight over values for both the complete and corresponding excluded nutrient solutions. The exception was S where there was no difference between excluded and 0.1 mM solutions. For Rhizoctonia dry weights in Fe excluded solutions were less than the complete solution, while dry weights in S excluded solutions were greater than the complete solution. At the 1.0 mM level Fe, K, and Mg dry weights were significantly increased over the dry weights produced in both the complete and deficient solutions.     

Effect of pharmacological agents on the activity of the circular and longitudinal smooth muscle layers of human fallopian tube ampullar segments

The in vitro determination of the effects of some pharmacological agents on the outer diameter and axial tension of human Fallopian tube ampullar segments showed that some drugs may act on the circular and longitudinal smooth muscle layers relatively separately. PGF2 alpha elicited an excitatory response in both muscle layers while norepinephrine and isoproterenol decreased the activity. Oxytocin and indomethacin had relatively limited effects on the spontaneous motility of the ampullar segments. The calcium antagonist verapamil inhibited the spontaneous periodic activity.     

Inhibition of RNA synthesis in yeast protoplasts by a peptide factor from Tetrahymena cells

Protoplasts of Schizosaccharomyces pombe, grown on a rich nutrient medium, were treated with a peptide factor isolated from cultures of the protozoan Tetrahymena pyriformis. The peptide factor is known to inhibit RNA synthesis in Tetrahymena. It has now been shown that the peptide factor also inhibits RNA synthesis in yeast protoplasts without affecting protein synthesis.     

Experimental analyses of competition between two species of bumble bees (Hymenoptera: apidae)

Summary Dynamical aspects of flower usage and forager body size in sympatric and experimentally-induced allopatric populations of Bombus flaviforns and Bombus rufocinctus were studied in 10 discrete subalpine meadows and over the last half of one summer. Results indicate that there is a high degree of asymmetry in the competitive effects and that B. flavifrons is the clear competitive and numerical dominant. When occurring alone, B. rufocinctus used the same spectrum of flowers in similar frequencies to that of B. flavifrons whose flower use was invariant over all meadows and treatments. When sympatric with B. flavifrons, B. rufocinctus was relegated to secondary, less preferred flowers. Shifts in flower use by B. rufocinctus were accompanied by changes in forager body-size: body weights were greater in allopatric populations of B. rufocinctus and smaller in those sympatric with B. flavifrons. Competitive dominance may be related to differences in species phenologies. Bombus flavifrons initiated colonies in the spring three weeks before B. rufocinctus and maintained higher densities over the summer; by virtue of greater numbers of foragers, it may control exploitation of the most profitable flowers.     

Relation of precipitation and temperature with yield of herbaceous plants in eastern Oregon

Eighteen years of herbage yields of range grasses and concomitant precipitation and temperature fluctuations were examined with correlation and regression techniques. Antecedent precipitation was the dominant factor influencing yield of perennial herbaceous species, while both temperature and precipitation were important for prediction of yield of downy bromegrass, a winter annual. Total yield of the herbaceous community was closely correlated with precipitation received during the September to June period (r = 0.92); however, September to March precipitation was also highly correlated (r = 0.89). These correlations provide timely and useful estimates of native range production on eastern Oregon ranges. Sixty to 92% of yield variation was accounted for by the regression models for 9 of the 12 species or species groups examined.