Duodenal Expression of 25 Hydroxyvitamin D3-1α-hydroxylase Is Higher in Adolescents Than in Children and Adults.

CONTEXT: Puberty is associated with increased dietary calcium absorption. However, little is known about the metabolic adaptations that enhance calcium absorption during puberty. OBJECTIVES: To investigate duodenal 25-hydroxy vitamin D-1α-hydroxylase (CYP 27B1) mRNA expression and duodenal 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) production in children, adolescents, and adults. DESIGN AND METHODS: CYP27B1a nd IGF1 mRNA expression and 1,25(OH)2D3 production were determined in duodenal biopsies. CYP27B1 expression was also determined after IGF1R inhibitor treatment of human and mice duodenal explants. mRNA expression was determined by RT-PCR, and CYP27B1 activity was determined by incubating duodenal explants with 25(OH)D3 and measuring 1,25(OH)2D3 production by radioimmunoassay. RESULTS: CYP27B1 mRNA expression was 13.7 and 10.4 times higher in biopsies from adolescents compared to adults and children, respectively. IGF1 mRNA expression was 30% and 45% higher in explants from adolescents and children, respectively, compared to adults. Inhibition of IGF1 receptor activity decreased CYP27B1 expression in explants from both mice (85%) and humans (24%). 1,25(OH)2D3 production reached a maximum velocity of 768 ± 268 pmol/l/mg protein at 748.8 nmol/l of 25(OH)D3 in children and adolescents, whereas the maximum velocity was 86.4 ± 43.2 pmol/l/mg protein in adults. The substrate concentration at which the enzyme shows half of its maximum activity was similar in all groups, ranging between 624 and 837 nmol/L of 25(OH)D3. CONCLUSIONS: Increased CYP27B1 expression and local duodenal 1,25(OH)2D3 production during puberty may be a metabolic adaptation that promotes dietary calcium absorption. IGF1, a major factor in skeletal growth, is also involved in the modulation of CYP27B1 expression in the gut and may increase calcium supply for the growing bone.

Effects of breastfeeding on body composition and maturational tempo in the rat.

BACKGROUND: Features of life history are subject to environmental regulation in the service of reproductive fitness goals. We have previously shown that the infant-to-childhood transition reflects the adaptive adjustment of an individual's size to the prevailing and anticipated environment. METHODS: To evaluate effects of weaning age on life-history traits in rats, we repeatedly measured length and body mass index (BMI), as well as physiological development and sexual maturation in pups weaned early (d16), normally (d21) or late (d26). Males were bred to females of the same weaning age group for four generations. RESULTS: Here, we show that the age at weaning from lactation regulates a rat's life history, growth, body composition and maturational tempo. We show that early-weaned rats developed faster than normal- or late-weaned rats; they are leaner and longer than late-weaned ones who are heavier and shorter. Early-weaned progeny develop more rapidly (that is, fur budding, pinnae detachment, eye opening); females show earlier vaginal opening and estrous and males show earlier onset of testicular growth. In generations 3 and 4, early-weaned rats bear larger litter sizes and heavier newborn pups. The entire traits complex is transmitted to subsequent generations from the paternal side. CONCLUSIONS: The findings presented here lend support to the proposition that the duration of infancy, as indexed by weaning age, predicts and perhaps programs growth, body composition, and the tempo of physiological development and maturation, as well as litter size and parity and, thereby, reproductive strategy.

Metabolic profiling in personalized medicine: bridging the gap between knowledge and clinical practice in Type 2 diabetes.

Type 2 diabetes mellitus (DM2) is the most commonly diagnosed metabolic disease and its prevalence is expected to increase. Epidemiological studies clearly show excess mortality associated with DM2, as well as an increased risk of DM2-related complications. Advances in personalized medicine would greatly improve patient care in the field of diabetes and other metabolic diseases. Prediction of the disease in asymptomatic patients as well as its harsh complications in patients already diagnosed is becoming a necessity, with the considerable increase in the cost of the treatment. In the current article, we review the known clinical, molecular metabolic and genetic biomarkers that should be integrated in a future bioinformatic platform to be used at the point-of-care, and discuss the challenges we face in applying this vision of personalized medicine for diabetes into reality.

Corynebacterium maris sp. nov., a marine bacterium isolated from the mucus of the coral Fungia granulosa.

A bacterial strain, designated Coryn-1(T), was isolated from mucus of the coral Fungia granulosa (northern Red Sea, Gulf of Eilat, Israel) by growth and enrichment of micro-organisms in agar spheres and subsequent plating. The bacterium was found to be a Gram-positive, non-motile, halotolerant, heterotrophic coccobacillus. Comparative 16S rRNA gene sequence analyses showed that strain Coryn-1(T) belonged to the genus Corynebacterium, exhibiting the highest levels of similarity (94 %) with the 16S rRNA gene sequence of Corynebacterium halotolerans YIM 70093(T). The novel strain grew well at 0.5-4.0 % salinity, at pH 7.2-9.0 and at 30-37 degrees C. The major cellular fatty acids were oleic acid (C(18 : 1)omega9c; 58 %), palmitic acid (C(16 : 0); 30 %) and tuberculostearic acid (10-methyl-C(18 : 0); 12 %). The DNA G+C content was 66.6 mol%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Coryn-1(T) represents a novel species, for which the name Corynebacterium maris sp. nov. is proposed. The type strain is Coryn-1(T) (=DSM 45190(T)=LMG 24561(T)).

Amorphus coralli gen. nov., sp. nov., a marine bacterium isolated from coral mucus, belonging to the order Rhizobiales.

A bacterial strain, designated RS.Sph.026(T), was isolated from mucus of the coral Fungia granulosa collected from the northern Red Sea (Gulf of Eilat, Israel). The bacterium was found to be Gram-negative, non-motile, halotolerant and heterotrophic. Comparative 16S rRNA gene sequence analyses showed that strain RS.Sph.026(T) belonged to the order Rhizobiales, with the highest levels of 16S RNA gene sequence similarity with Rhodobium orientis (92 %). Strain RS.Sph.026(T) grew optimally at a salinity of 3-4 %, pH 7.5-8 and 25-30 degrees C. The major cellular fatty acids were cis-7-octadecenoic acid (C(18 : 1)omega7small es, Cyrillic; 57.2 %) and C(19 : 0) cyclo omega8small es, Cyrillic (15.5 %). The DNA G+C content of strain RS.Sph.026(T) was 67.1 mol%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain RS.Sph.026(T) represents a novel genus and species in the order Rhizobiales, for which the name Amorphus coralli gen. nov., sp. nov. is proposed. The type strain is RS.Sph.026(T) (=LMG 24307(T)=DSM 19760(T)).