Modulation of postendocytic sorting of G protein-coupled receptors

Recycling of the mu opioid receptor to the plasma membrane after endocytosis promotes rapid resensitization of signal transduction, whereas targeting of the delta opioid receptor (DOR) to lysosomes causes proteolytic down-regulation. We identified a protein that binds preferentially to the cytoplasmic tail of the DOR as a candidate heterotrimeric GTP-binding protein (G protein)-coupled receptor-associated sorting protein (GASP). Disruption of the DOR-GASP interaction through receptor mutation or overexpression of a dominant negative fragment of GASP inhibited receptor trafficking to lysosomes and promoted recycling. The GASP family of proteins may modulate lysosomal sorting and functional down-regulation of a variety of G protein-coupled receptors.     

Tracking of energy and nutrient intakes from adolescence to young adulthood: the experiences of the Young Hearts Project, Northern Ireland

OBJECTIVE: To assess tracking of energy and nutrient intakes between adolescence and young adulthood. DESIGN: Longitudinal study of a random sample of adolescents (aged 15 years at baseline). The extent of tracking of dietary intakes (assessed by diet history) was investigated using weighted kappa statistics (kappa). SETTING: Northern Ireland population survey. SUBJECTS: Adolescents who participated in the Young Hearts Project, Northern Ireland at age 15 years, and subsequently at young adulthood aged between 20 and 25 years (n=245 males, n=231 females). RESULTS: Despite overall increases in height and weight (both P<0.001), increases in body mass index in males (P<0.001) and body fatness in females (P<0.001), median reported intakes of energy (kJ kg(-1) day(-1)), carbohydrate (g day(-1)) and fat (g day(-1)) decreased (all P<0.001) over time. Expressed as nutrient densities (per MJ), diets at young adulthood were overall richer in thiamin, vitamin B6, total folate (all P<0.001), vitamin C (P<0.01) and vitamin D (P<0.05). Whereas the nutrient density of the males' diets decreased over time for calcium (P<0.05) and vitamin A (P<0.001), iron and riboflavin densities increased in the females' diet (P<0.001). Tracking of energy (MJ day(-1)) and nutrient intakes (expressed per MJ day(-1)) at the individual level was only poor to fair (all kappa<0.25), indicating substantial drift of subjects between the low, medium and high classes of intake with increasing age. CONCLUSIONS: These data suggest that individual dietary patterns exhibited at 15 years of age are unlikely to be predictive of dietary intakes at young adulthood.     

Using a GnRH agonist to obtain an index of testosterone secretory capacity in the cockatiel (Nymphicus hollandicus) and sulphur-crested cockatoo (Cacatua galerita)

Objective   Validation of a stimulation test for determining the steroidogenic capacity of the parrot testis. The major aim was to characterise testosterone secretion after injection of a gonadotropin-releasing hormone agonist (GnRHa), then use the test to investigate seasonal reproduction in the male cockatiel.
Procedure   A synthetic GnRHa (buserelin; 8.0 µg of peptide/kg bodyweight) was injected IM into male cockatiels (n = 7) and sulphur-crested cockatoos (n = 3) and serial blood samples collected at 0, 30, 60, 90 and 120 min after administration. Once validated, the technique was subsequently used to examine seasonal changes (23 months) in the testosterone profile of a captive cockatiel population.
Results   Injection of buserelin resulted in a significant increase in the testosterone concentration of cockatiel plasma, with maximal concentrations occurring at approximately 60 (1.33 ± 0.08 ng/mL) to 90 min (1.22 ± 0.08 ng/mL) after injection. Although no clear pattern of seasonal variation in testosterone secretion was detected in cockatiel plasma, samples taken 60 and 90 min after administration showed a significant increase in all seasons. Injection of buserelin in the sulphur-crested cockatoo also resulted in increased testosterone secretion, with maximal concentrations obtained after 90 min.
Conclusion   Buserelin can be used to obtain a reliable index of the prevailing testosterone capacity of the cockatiel and cockatoo testis. With further studies, this test may be incorporated into clinical assessment of reproductive status.     

Genetic Variation for Maize Epicuticular Wax Response to Drought Stress at Flowering

Drought stress is thought to promote epicuticular wax accumulation on maize leaves, which reduces plant water loss. We evaluated 62 maize inbred lines and their hybrid testcross progeny for epicuticular wax accumulation on flag leaves at flowering under full and limited irrigation regimes. Extracted wax was measured as a percentage of wax weight to leaf weight (WLW) and leaf area (WLA). Eleven genotypes had above average WLW as both inbred lines and hybrid testcrosses. Thirteen genotypes had above average WLA as either inbred lines or hybrid testcrosses. The drought treatment did not significantly alter WLW or WLA. Heritability of WLW was 0.17 (inbred lines) and 0.58 (hybrid testcrosses). Heritability of WLA was 0.41 (inbred lines) and 0.59 (hybrid testcrosses), suggesting it is a better trait than WLW for epicuticular wax screening. Correlations (r) between inbred lines and their testcross progeny were 0.44 and 0.18, for WLW and WLA, respectively. Heritability of grain weight per ear and plot yield was highest in hybrid testcrosses, with no correlation between inbred and hybrid germplasm. It is not warranted to evaluate epicuticular wax accumulation as the sole drought tolerance mechanism. However, it may be a good secondary trait to observe in relation to grain yield production in hybrids tested under water‐limiting conditions.     

Effect of feeding sorghum ergot (Claviceps africana) to sows during mid‐lactation on plasma prolactin and litter performance

Diets containing 3% sorghum ergot (16 mg alkaloids/kg, including 14 mg dihydroergosine/kg) were fed to 12 sows from 14 days post‐farrowing until weaning 14 days later, and their performance was compared with that of 10 control sows. Ergot‐fed sows displayed a smaller weight loss during lactation of 24 kg/head vs. 29 kg/head in control sows (p > 0.05) despite feed consumption being less (61 kg/head total feed intake vs. 73 kg/head by control sows; p < 0.05). Ergot‐fed sows had poorer weight gain of litters over the 14‐day period (16.6 kg/litter vs. 28.3 kg/litter for controls; p < 0.05) despite an increase in consumption of creep feed by the piglets from the ergot‐fed sows (1.9 kg/litter compared with 1.1 kg/litter by the control; p > 0.05). Sow plasma prolactin was reduced with ergot feeding after 7 days to 4.8 μg/l compared with 15.1 μg/l in the control sows (p < 0.01) and then at weaning was 4.9 μg/l compared with 8.0 μg/l (p < 0.01) in the control sows. Two sows fed ergot ceased lactation early, and the above sow feed intakes, body weight losses with litter weight gains and creep consumption indirectly indicate an ergot effect on milk production.     

Starving the soil of plant inputs for 50 years reduces abundance but not diversity of soil bacterial communities

If soil communities rely on plant-derived carbon, is biodiversity lost when this primary source is removed? Soil microbial and mesofaunal communities at the Rothamsted Highfield site were compared under a mixed grass sward, arable rotation and a section maintained as a bare-fallow for the past 50 years by regular tillage. Organic matter reserves have been degraded and microbial and mesofaunal numbers and mite diversity have declined in this unique bare-fallow site, where fresh carbon inputs have been drastically reduced. However, it supports a species-rich metabolically active bacterial community of similar diversity to that in soil maintained as grass sward. Thus in contrast to soil mesofauna, bacterial diversity (but not abundance) is apparently independent of plant inputs.     

Mariner 9 television reconnaissance of Mars and its satellites: preliminary results

At orbit insertion on 14 November 1971 the Martian surface was largely obscured by a dust haze with an extinction optical depth that ranged from near unity in the south polar region to probably greater than 2 over most of the planet. The only features clearly visible were the south polar cap, one dark, spot in Nix Olympica, and three dark spots in the Tharsis region. During the third week the atmosphere began to clear and surface visibility improved, but contrasts remained a fraction of their normal value. Each of the dark spots that apparently protrude through most of the dust-filled atmosphere has a crater or crater complex in its center. The craters are rimless and have featureless floors that, in the crater complexes, are at different levels. The largest crater within the southernmost spot is approximately 100 kilometers wide. The craters apparently were formed by subsidence and resemble terrestrial calderas. The south polar cap has a regular margin, suggsting very flat topography. Two craters outside the cap have frost on their floors; an apparent crater rim within the cap is frost free, indicating preferentia loss of frost from elevated ground. If this is so then the curvilinear streaks, which were frost covered in 1969 and are now clear of frost, may be low-relief ridges. Closeup pictures of Phobos and Deimos show that Phobos is about 25 +/-5 by 21 +/-1 kilometers and Deimos is about 13.5 +/- 2 by 12.0 +/-0.5 kilometers. Both have irregular shapes and are highly cratered, with some craters showing raised rims. The satellites are dark objects with geometric albedos of 0.05.