The effect of a low-protein diet in pregnancy on offspring renal calcium handling

Low birth weight humans and rats exposed to a low-protein diet in utero have reduced bone mineral content. Renal calcium loss during the period of rapid skeletal growth is associated with bone loss. Because young rats exposed to low protein display altered renal function, we tested the hypothesis that renal calcium excretion is perturbed in this model. Pregnant Wistar rats were fed isocalorific diets containing either 18% (control) or 9% (low) protein throughout gestation. Using standard renal clearance techniques, Western blotting for renal calcium transport proteins, and assays for Na(+)-K(+)-ATPase activity and serum calcitropic hormones, we characterized calcium handling in 4-wk-old male offspring. Histomorphometric analyses of femurs revealed a reduction in trabecular bone mass in low-protein rats. Renal calcium (control vs. low protein: 10.4 +/- 2.1 vs. 27.6 +/- 4.5 nmol x min(-1) x 100 g body wt(-1); P < 0.01) and sodium excretion were increased, but glomerular filtration rate was reduced in low-protein animals. Total plasma calcium was reduced in low-protein rats (P < 0.01), but ionized calcium, serum calcitropic hormone concentrations, and total body calcium did not differ. There was no significant change in plasma membrane Ca(2+)-ATPase pump, epithelial calcium channel, or calbindin-D(28K) expression in low-protein rat kidneys. However, Na(+)-K(+)-ATPase activity was 36% lower (P < 0.05) in low-protein rats. These data suggest that the hypercalciuria of low-protein rats arises through a reduction in passive calcium reabsorption in the proximal tubule rather than active distal tubule uptake. This may contribute to the reduction in bone mass observed in this model.     

Redescription of a poorly known marine ciliate, Leptoamphisiella vermis Gruber, 1888 n. g., n. comb. (ciliophora, stichotrichia, pseudoamphisiellidae), from the Yellow Sea, China

Leptoamphisiella vermisGruber, 1888 n. g., n. comb. (basionym Epiclintes vermisGruber, 1888) is an extraordinarily large and worm-like marine stichotrichous ciliate. Based on a population isolated recently from coastal waters of Qingdao, China, the living morphology and infraciliature are redescribed and its taxonomic position is defined. Accordingly, a new diagnosis for this species is suggested: large, marine Leptoamphisiella with a conspicuous layer of pellicular alveoli; 400-1000 microm x 40-70 microm in vivo; body band-like, highly flexible; about 40 membranelles; always three frontal and two buccal cirri; 52-80 transverse cirri (TC) extending to the posterior end of the buccal field; 57-79 left midventral and 44-62 right midventral cirri; 62-102 cirri in left and 63-91 cirri in right marginal rows (MR); 9-13 dorsal kineties that extend the full body length; about 100 macronuclear nodules and 5-13 micronuclei. The diagnosis for the new genus is as follows: vermiform Pseudoamphisiellidae with strongly contractile body, differentiated frontal, buccal, and highly developed TC; two remarkably separated midventral rows; one MR on each side of the body; frontoterminal and caudal cirri absent. Leptoamphisiella vermis n. comb. is fixed as the type species of the new genus.     

Disaccharidase activities in camel small intestine: biochemical investigations of maltase-glucoamylase activity

Disaccharidases (maltase, cellobiase, lactase, and sucrase), alpha-amylase, and glucoamylase in the camel small intestine were investigated to integrate the enzymatic digestion profile in camel. High activities were detected for maltase and glucoamylase, followed by moderate levels of sucrase and alpha-amylase. Very low activity levels were detected for lactase and cellobiase. Camel intestinal maltase-glucoamylase (MG) was purified by DEAE-Sepharose and Sephacryl S-200 columns. The molecular weight of camel small intestinal MG4 and MG6 were estimated to be 140,000 and 180,000 using Sephacryl S-200. These values were confirmed by SDS-PAGE, where the two enzymes migrated as single subunits. This study encompassed characterization of MGs from camel intestine. The Km values of MG4 and MG6 were estimated to be 13.3 mM and 20 mM maltose, respectively. Substrate specificity for MG4 and MG6 indicated that the two enzymes are maltase-glucoamylases because they catalysed the hydrolysis of maltose and starch with alpha-1,4 and alpha-1,6 glycosidic bonds, but not sucrose with alpha-1,2 glycosidic bond which was hydrolyzed by sucrase-isomaltase. Camel intestinal MG4 and MG6 had the same optimum pH at 7.0 and temperature optimum at 50 degrees C and 40 degrees C, respectively. The two enzymes were stable up to 50 degrees C and 40 degrees C, followed by strong decrease in activity at 60 degrees C and 50 degrees C, respectively. The effect of divalent cations on the activity of camel intestinal MG4 and MG6 was studied. All the examined divalent cations Ca(2+), Mn(2+), Mg(2+), Co(2+) and Fe(3+) had slight effects on the two enzymes except Hg(2+) which had a strong inhibitory effect. The effect of different inhibitors on MG4 and MG6 indicated that the two enzymes had a cysteine residue.     

The positive effect of the decreased NADPH-preferring activity of xylose reductase from Pichia stipitis on ethanol production using xylose-fermenting recombinant Saccharomyces cerevisiae

We focused on the effects of a mutation of xylose reductase from Pichia stipitis (PsXR) on xylose-to-ethanol fermentation using recombinant Saccharomyces cerevisiae transformed with PsXR and PsXDH (xylitol dehydrogenase from P. stipitis) genes. Based on inherent NADH-preferring XR and several site-directed mutagenetic studies using other aldo-keto reductase enzymes, we designed several single PsXR mutants. K270R showing decreased NADPH-preferring activity without a change in NADH-preferring activity was found to be a potent mutant. Strain Y-K270R transformed with K270R PsXR and wild-type PsXDH showed a 31% decrease in unfavorable xylitol excretion with 5.1% increased ethanol production as compared to the control in the fermentation of 15 g l(-1) xylose and 5 g l(-1) glucose.     

Construction of Adipogenic ceRNA Network Based on lncRNA Expression Profile of Adipogenic Differentiation of Human MSC Cells

Biochemical Genetics - The Long non-coding RNA (lncRNA) expression profile data of ten samples including human Mesenchymal Stem Cell (MSC) adipogenic differentiation 0, 3, and 6&nbsp;days from...     

Genetic Determinants of the Network of Primary Metabolism and Their Relationships to Plant Performance in a Maize Recombinant Inbred Line Population

Deciphering the influence of genetics on primary metabolism in plants will provide insights useful for genetic improvement and enhance our fundamental understanding of plant growth and development. Although maize (Zea mays) is a major crop for food and feed worldwide, the genetic architecture of its primary metabolism is largely unknown. Here, we use high-density linkage mapping to dissect large-scale metabolic traits measured in three different tissues (leaf at seedling stage, leaf at reproductive stage, and kernel at 15 d after pollination [DAP]) of a maize recombinant inbred line population. We identify 297 quantitative trait loci (QTLs) with moderate (86.2% of the mapped QTL, R² = 2.4 to 15%) to major effects (13.8% of the mapped QTL, R² >15%) for 79 primary metabolites across three tissues. Pairwise epistatic interactions between these identified loci are detected for more than 25.9% metabolites explaining 6.6% of the phenotypic variance on average (ranging between 1.7 and 16.6%), which implies that epistasis may play an important role for some metabolites. Key candidate genes are highlighted and mapped to carbohydrate metabolism, the tricarboxylic acid cycle, and several important amino acid biosynthetic and catabolic pathways, with two of them being further validated using candidate gene association and expression profiling analysis. Our results reveal a metabolite-metabolite-agronomic trait network that, together with the genetic determinants of maize primary metabolism identified herein, promotes efficient utilization of metabolites in maize improvement.     

Crocin Abrogates Carbon Tetrachloride‐Induced Renal Toxicity in Rats via Modulation of Metabolizing Enzymes and Diminution of Oxidative Stress,Apoptosis, and Inflammatory Cytokines

This work aimed at investigating the potential modulatory effects and mechanisms of crocin against CCl₄‐induced nephrotoxicity. Forty male rats were allocated for three weeks treatment with corn oil, CCl₄, crocin, or crocin plus CCl₄. Crocin effectively mitigated CCl₄‐induced kidney injury as evidenced by amelioration of alterations in kidney histopathology, renal weight/100 g body weight ratio and kidney functions. Crocin modulated CCl₄‐induced disturbance of kidney cytochrom‐P450 subfamily 2E1 and glutathione‐S‐transferase. The attenuation of crocin to kidney injury was also associated with suppression of oxidative stress via reduction of lipid peroxides along with induction of renal glutathione content and enhancement of superoxide dismutase, glutathione peroxidase, and catalase activities. Crocin mitigated CCl₄‐induced elevation of the renal levels of tumor necrosis factor‐alpha, interleukin‐6, prostaglandin E2, and active caspases‐3. Collectively, crocin alleviated CCl₄‐induced renal damage via modulation of kidney metabolizing enzymes, suppression of oxidative stress, inhibition of inflammatory cytokines, PGE2, and active caspase3 in kidney.