Development of Models to Estimate Total Soil Carbon across Different Croplands at a Regional Scale Using RGB Photography.

A quick, accurate and cost-effective method for estimating total soil carbon is necessary for monitoring its levels due to its environmentally and agronomically irreplaceable importance. There are several impediments to both laboratory analysis and spectroscopic sensor technology because the former is both expensive and time-consuming whereas the initial cost of the latter is too high for farmers to afford. RGB photography obtained from digital cameras could be used to quickly and cheaply estimate the total carbon (TC) content of the soil.

Effects of prostaglandin E2 and indomethacin on 25-hydroxyvitamin D3-1 alpha-hydroxylase activity in isolated kidney cells of normal and streptozotocin-induced diabetic rats.

The effects of prostaglandin E2 (PGE2) (1 microM) and indomethacin (IN) (20 microM) on 1,25 dihydroxyvitamin D3 production were studied in renal cell suspensions isolated from control, streptozotocin-induced diabetic, and insulin-treated diabetic rats. Renal cortex cells were isolated by enzymatic digestion, and preincubated for 30 min at 37 degrees C with the appropriate additive(s) followed by a 1 h incubation with 8 nM 25-hydroxyvitamin D3 in serum-free medium. Radioactivity incorporated into that fraction of the cell suspension extract co-eluting with synthetic 1,25-dihydroxyvitamin D3 on high pressure liquid chromatography was determined.

The duodenal 1 alpha,25-dihydroxyvitamin D3 receptor in rats with experimentally induced diabetes.

Studies in the rat with streptozotocin-induced diabetes of short and long duration revealed decreased circulating 1 alpha,25-dihydroxyvitamin D [1,25-(OH)2D] levels and an intact 1,25-(OH)2D3 duodenal cytosolic receptor with a sedimentation coefficient of 3.3S. Whereas no significant alterations in the equilibrium dissociation constant (Kd) were observed in the diabetic animals, the number of 1,25-(OH)2D3-binding sites was increased in the animals with short term (235 +/- 48 vs.

Vitamin D metabolism in the chronic streptozotocin-induced diabetic rat.

Alterations in circulating vitamin D3 metabolites have been documented in both experimental and human diabetes mellitus. Using a recirculating hepatic perfusion system and in vitro kidney mitochondrial assays, we studied vitamin D3 hydroxylation in control and insulin-deficient rats 6 weeks after the induction of streptozotocin-diabetes. Vitamin D3-25-hydroxylase activity, assessed by hepatic conversion of [3H]vitamin D3 to [3H]25-hydroxyvitamin D3 during a 4-h perfusion, was similar in diabetic and control animals.