Stress related changes in the architecture of seedlings of three provenances ofEucalyptus camaldulensis Dehnh

Abscisic acid (10^?4M) applied via absorbent discs bound to the stems of 6 wk oldE. camaldulensis seedlings caused changes in leaf shape and orientation similar to those induced by nutritional and water stress. Seedlings from the driest provenance, Tennant Creek, were more responsive to ABA than seedlings from the wettest provenance, Katherine, and the response of Petford seedlings was intermediate. Likewise, Tennant Creek seedlings were most, and Katherine seedlings least, responsive to water and/or nutritional stress. Seedlings that responded to the application of ABA produced prematurely strengthened, linear leaves with the lamina rotated from horizontal to vertical. The ability of Tennant Creek seedlings to readily assume this form may be a specific adaptation for the particularly difficult conditions in their natural environment.     

Dietary intake and the insulin-like growth factor system: effects of migration in two related populations in India and Britain with markedly different dietary intake

BACKGROUND: The insulin-like growth factor (IGF) system is implicated in the pathogenesis of diabetes and cardiovascular disease. OBJECTIVE: We report the effects of total energy intake on the IGF system in two populations with markedly different dietary macronutrient intake and cardiovascular event rate. DESIGN, SUBJECTS AND SETTING: Dietary macronutrient intake was measured in a specific Gujarati migrant community in Sandwell, UK (n=205) compared with people still resident in the same villages of origin in India (n=246). Fasting IGF-I, IGF-binding protein (IGFBP)-1 and IGFBP-3, insulin and glucose (0 and 2-hour) were measured. RESULTS: Total energy and total fat intake were higher in UK migrants, as were IGFBP-3 and IGF-I (mean (95% confidence interval): 145.9 (138.1-153.6) vs. 100.9 (94.6-107.3) ng ml(-1); F=76.6, P<0.001). IGFBP-1 was lower in UK migrants (29.5 (25.9-33.0) vs. 56.5 (50.6-62.5) microg l(-1); F=48.4, P<0.001). At both sites, IGF-I correlated positively with total energy (Spearman's rho=0.45, P<0.001) and total fat (rho=0.44, P<0.001) as did IGFBP-3 with total energy (rho=0.21, P<0.05) and fat (rho=0.26, P<0.001). Conversely, in Indian Gujaratis, IGFBP-1 fell with increasing total energy (rho=-0.27, P<0.001) and fat intake (rho=-0.26, P<0.01) but not in UK Gujaratis. Multiple linear regression modelling showed that increasing quartiles of fat intake were associated with higher IGF-I (beta=0.42, P=0.007) independent of age, body mass index, plasma insulin, fatty acids and 2-hour glucose. CONCLUSION: In these genetically similar groups, migration to the UK and adoption of a different diet is associated with marked changes in the IGF system, suggesting that environmental factors profoundly modulate serum concentrations and actions of IGFs.     

Demographic, familial and trait predictors of fruit and vegetable consumption by pre-school children

OBJECTIVE: To examine the contribution to fruit and vegetable eating in children of potential predictive variables within the domains of demographics, parental feeding practices and personality traits. DESIGN: Cross-sectional survey. SETTING: Questionnaires were distributed to parents through 22 London nursery schools. SUBJECTS: Questionnaires were completed and returned by 564 parents or principal caregivers of 2-6-year-old children. RESULTS: Significant predictors of children's fruit and vegetable intake emerged from all three domains examined. Demographic variables associated with child's vegetable consumption were mother's education and child's age and gender. Only ethnicity was significantly associated with fruit consumption. Parental consumption, breast-feeding and early introduction to fruit and vegetables were related to intake of both. Family meal times were associated with higher intake of vegetables, but not of fruit. Two characteristics of children themselves (food neophobia and enjoyment of food) were strongly related to the consumption of fruit and vegetables. Subsequent multivariate analyses revealed that parental intake and child food neophobia independently predicted intake of both foods. In the presence of these, fruit consumption was affected by breast-feeding and early introduction to fruit, whereas vegetable consumption was related only to child's gender and enjoyment of food. CONCLUSIONS: These findings may be used to inform future interventions aimed at increasing children's consumption of fruit and vegetables. Parents should be made aware of the possible impact of their own behaviour on the eating habits of their children.     

Species diversity: benthonic foraminifera in Western north atlantic

Maximum species diversity occurs at abyssal depths of greater than 2500 meters. Other diversity peaks occur at depths of 35 to 45 meters and 100 to 200 meters. The peak at 35 to 45 meters is due to species equitability, whereas the other two peaks correspond to an increase in the number of species.     

Is orientation-specific color adaptation in human vision due to edge detectors, afterimages, or "dipoles"?

After one looks alternately at red vertical and green horizontal stripes, vertical and horizontal white stripes appear greenish and pink, respectively. This color aftereffect might imply that contour-detecting cells participate in human vision, or might simply be due to afterimages. A procedure that precludes afterimages still yields aftereffects, but sensory units less complex than edge detectors could be responsible.     

Endothelin: a novel peptide in the posterior pituitary system

Endothelin (ET), originally characterized as a 21-residue vasoconstrictor peptide from endothelial cells, is present in the porcine spinal cord and may act as a neuropeptide. Endothelin-like immunoreactivity has now been demonstrated by immunohistochemistry in the paraventricular and supraoptic nuclear neurons and their terminals in the posterior pituitary of the pig and the rat. The presence of ET in the porcine hypothalamus was confirmed by reversed-phase high-pressure liquid chromatography and radioimmunoassay. Moreover, in situ hybridization demonstrated ET messenger RNA in porcine paraventricular nuclear neurons. Endothelin-like immunoreactive products in the posterior pituitary of the rat were depleted by water deprivation, suggesting a release of ET under physiological conditions. These findings indicate that ET is synthesized in the posterior pituitary system and may be involved in neurosecretory functions.