Kisspeptin neurones in the posterodorsal medial amygdala modulate sexual partner preference and anxiety in male mice.

The posterodorsal medial amygdala (MePD) is a neural site in the limbic brain involved in regulating emotional and sexual behaviours. There is however limited information on the specific neuronal cell type in the MePD functionally mediating these behaviours in rodents. The recent discovery of a significant kisspeptin neurone population in the MePD has raised interest in the possible role of kisspeptin and its cognate receptor in sexual behaviour. This study therefore tested the hypothesis that the MePD kisspeptin neurone population is involved in regulating attraction towards opposite sex conspecifics, sexual behaviour, social interaction and anxiety response by selectively stimulating these neurones using the novel pharmacosynthetic DREADDs (designer receptors exclusively activated by designer drugs) technique. Adult male Kiss-Cre mice received bilateral stereotaxic injections of a stimulatory DREADD viral construct (AAV-hSyn-DIO-hM3D(Gq)-mCherry) targeted to the MePD which were activated by intraperitoneal (i.p.) injection of clozapine-N-oxide (CNO). Socio-sexual behaviours were assessed in a counter-balanced fashion after i.p. injection of either saline or CNO (5mg/kg). Selective activation of MePD kisspeptin neurones by CNO significantly increased the time spent by male mice in investigating an oestrous female as well as duration of social interaction. Additionally, after CNO injection the mice appeared less anxious; evidenced by longer exploratory time in the open arms of the elevated plus maze. However, levels of copulatory behaviour were comparable between CNO and saline treated controls. These data indicate that DREADD-induced activation of MePD kisspeptin neurones enhances sexual partner preference in males and social interaction and decreases anxiety, suggesting a key role played by MePD kisspeptin in sexual motivation and social behaviour. This article is protected by copyright. All rights reserved.This work was supported by the Medical Research Council, UK. DAA is a Commonwealth Scholar funded by the UK Government

Model estimates of CO2 emissions from soil in response to global warming

One effect of global warming will be to accelerate the decomposition of soil organic matter, thereby releasing CO2 to the atmosphere, which will further enhance the warming trend 1-7. Such a feedback mechanism could be quantitatively important, because CO2 is thought to be responsible for approximately 55% of the increase in radiative forcing arising from anthropogenic emissions of gases to the atmosphere 8, and there is about twice as much carbon in the top metre of soil as in the atmosphere 9. Here we use the Rothamsted model for the turnover of organic matter in soil 3 to calculate the amount of CO2 that would be released from the world stock of soil organic matter if temperatures increase as predicted, the annual return of plant debris to the soil being held constant. If world temperatures rise by 0.03-degrees-C yr-1 (the increase considered as most likely by the Intergovernmental Panel on Climate Change 8), we estimate that the additional release of CO2 from soil organic matter over the next 60 years will be 61 x 10(15) gC. This is approximately 19% of the CO2 that will be released by combustion of fossil fuel during the next 60 years if present use of fuel continues unabated.&nbsp

The Healthy Eating Index and Youth Healthy Eating Index Are Unique, Nonredundant Measures of Diet Quality among Low-Income, African American Adolescents12

Chronic disease is related to poor diet quality. The Healthy Eating Index (HEI) was developed to assess diet quality. The Youth HEI (YHEI) is an adaptation of the HEI for use with children and adolescents. The objectives were to compare HEI and YHEI scores among adolescents at risk for chronic disease and to compare associations between the scores and health indicators. This cross-sectional study included 2 low-income, urban African American adolescent samples (Challenge, n = 196; Three Generation, n = 121). HEI and YHEI scores were calculated from a FFQ and compared with BMI, body composition, and micronutrient, energy, and dietary intakes. YHEI scores were lower than HEI scores across both adolescent samples (Challenge, 48.94 ± 9.31 vs. 62.83 ± 11.75; Three Generation, 47.08 ± 9.65 vs. 59.93 ± 11.27; P < 0.001). Females (64.47 ± 11.70) had higher HEI scores than males (61.15 ± 11.61) (P < 0.05), but there was no gender difference in YHEI scores. HEI and YHEI scores were associated with higher micronutrient and total energy intakes (r = 0.19–0.76; P < 0.05). Higher percent body/abdominal fat was associated with lower HEI scores (r = −0.17 to −0.19; P < 0.05) but not with YHEI scores. BMI was not associated with either HEI or YHEI scores. In conclusion, many adolescents were consuming diets that placed them at risk for developing chronic disease. Although both the HEI and YHEI are useful in assessing diet quality, the HEI is inversely associated with body composition, a predictor of chronic disease, and accounts for gender differences in the Dietary Guidelines, whereas the YHEI discounts nutrient-poor, energy-dense foods