A Mutation in CTSK Gene in an Autosomal Recessive Pycnodysostosis Family of Chinese Origin.

Pycnodysostosis is a rare autosomal recessive skeletal dysplasia characterized by short stature, osteosclerosis, acro-osteolysis, frequent fractures, and skull deformities. Mutation in the gene encoding cathepsin K (CTSK), which is a lysosomal cysteine protease, has been found to be responsible for this disease. Here we reported a consanguineous Chinese family with 1 affected individual demonstrating autosomal recessive pycnodysostosis with recurrent kidney stone, a new clinical manifestation which has not been reported in patients of pycnodysostosis before. To identify the pathogenic mutation, we evaluated the patient clinically, biochemically, and radiographically. To screen for mutations in the CTSK gene of the patient and his family members, all of its exons and exon-intron junctions were PCR amplified from genomic DNA and sequenced. Sequence analysis of the patient's CTSK gene revealed homozygosity for a missense mutation (c.746T>C) in exon 6, which leads to amino change (p.Ile249Thr) in the mature CTSK protein. This mutation was firstly reported by Michela Donnarumma and his colleagues in 2007 in a Spanish family. Our study strengthens the role of this particular mutation in the pathogenesis of pycnodysostosis.

Novel TRPM6 mutations in familial hypomagnesemia with secondary hypocalcemia.

BACKGROUND: Familial hypomagnesemia with secondary hypocalcemia (HSH) is a rare autosomal recessive disease characterized by severe hypomagnesemia and hypocalcemia associated with neurological symptoms, including generalized seizures, tetany and muscle spasms, which are refractory to anticonvulsant treatment. The pathophysiological hallmarks of HSH are the impaired intestinal absorption of magnesium accompanied by renal magnesium wasting as a result of a reabsorption defect in the distal convoluted tubule. Mutations in TRPM6, the gene encoding the transient receptor potential cation channel subfamily member 6, have been found to be responsible for this disease. In the present study, we report a Chinese family with 2 sisters affected with severe HSH, and elucidate the characteristics of TRPM6 gene mutations in these 2 patients. METHODS: We evaluated the clinical, laboratory, and radiographic findings. All 39 TRPM6 exons and flanking exon-intron junctions from genomic DNA were amplified and sequenced in 2 affected members suffering from HSH and their family. RESULTS: We found two novel mutations in the family, one frameshift mutation (c.1196delC) and one non-sense mutation (c.4577G>A). These mutations were predicted to result in a complete loss of function of TRPM6. Both of the sisters were compound heterozygotes for these mutations. CONCLUSION: Our results suggested that the compound heterozygous mutations in TRPM6 were responsible for HSH in the Chinese family.

Structural properties and emulsification of myofibrillar proteins from hairtail (Trichiurus haumela) at different salt ions.

The structural properties and emulsification of myofibrillar proteins (MPs) are susceptibly affected by salt ions. The effect of different salt ions on the structural properties and emulsification of MPs from hairtail (Trichiurus haumela) remains unclear. Hairtail MPs were analyzed under different ion treatments of Na+, K+, Ca2+ and Mg2+. MPs at K+ and Na+ treatment showed a similar trend on salt effect due to the unfolding of proteins under salt ions. However, the excessive electrostatic effect of divalent ions could enhance protein aggregation, especially at Ca2+ and Mg2+. The ß-sheet of MPs at different salt ions interconverted with α-helix and random coil at ionic strengths from 0.1 mol/L to 1.0 mol/L. The surface hydrophobicity and active sulfhydryl content of MPs increased with the improvement of ionic strengths at 0-0.8 mol/L. Under Ca2+ and Mg2+ treatments, the turbidity of MPs was low compared to that under the treatment of Na+ and K+. Additionally, the emulsification of hairtail MPs treated with different ions was improved at an ionic strength of 0.6 mol/L. This study can contribute to using salts in constructing fish protein-based emulsions for manufacturing emulsified surimi products and promoting the development and utilization of hairtail proteins.

Characteristics and potential application of myofibrillar protein from golden threadfin bream (Nemipterus virgatus) complexed with chitosan.

The strategies to broaden the applications of proteins involve their modification with polysaccharides. However, the characteristics and application of myofibrillar proteins (MPs) from golden threadfin bream (Nemipterus virgatus) complexed with chitosan (CS) are still unclear. Therefore, the characteristics of MPs complexed with CS and their application were investigated at different MP/CS ratios (100:0-80:20 (w/w)). The turbidity of MP/CS complexes was small at the MP/CS ratio of 95:5 (w/w). Besides, CS addition induced changes in MP structure to make it hydrophilic. Secondary structure analysis showed that α-helix and ß-turn interconverted with ß-sheet and random coil after the addition of CS. Additionally, the thermal stability of MP/CS mixtures enhanced after the addition of CS and the MP/CS mixtures at the ratio of 95:5 (w/w) had a relatively compact structure. High internal phase emulsions (HIPEs) prepared at the MP/CS ratio of 95:5 (w/w) were relatively stable compared to those at the other ratios. Consequently, MP/CS mixtures at suitable ratios possess the potential ability to prepare HIPEs. These results exhibit that MP/CS mixtures may be applied for constructing food-graded emulsion delivery systems with a high internal phase in the food industry.

Oxygen vacancies engineering in electrocatalysts nitrogen reduction reaction.

Ammonia is important, both as a fertilizer and as a carrier of clean energy, mainly produced by the Haber-Bosch process, which consumes hydrogen and emits large amounts of carbon dioxide. The ENRR (Electronchemical Nitrogen Reduction Reaction) is considered a promising method for nitrogen fixation owing to their low energy consumption, green and mild. However, the ammonia yield and Faraday efficiency of the ENRR catalysts are low due to the competitive reaction between HER and NRR, the weak adsorption of N2 andthe strong N≡N triple bond. Oxygen vacancy engineering is the most important method to improve NRR performance, not only for fast electron transport but also for effective breaking of the N≡N bond by capturing metastable electrons in the antibonding orbitals of nitrogen molecules. In this review, the recent progress of OVs (oxygen vacancies) in ENRR has been summarized. First, the mechanism of NRR is briefly introduced, and then the generation methods of OVs and their applicationin NRR are discussed, including vacuum annealing, hydrothermal method, hydrogen reduction, wet chemical reduction, plasma treatment and heterogeneous ion doping. Finally, the development and challenges of OVs in the field of electrochemical nitrogen fixation are presented. This review shows the important areas of development of catalysts to achieve industrially viable NRR.

FGF23 and Phosphate Wasting Disorders.

A decade ago, only two hormones, parathyroid hormone and 1,25(OH)2D, were widely recognized to directly affect phosphate homeostasis. Since the discovery of fibroblast growth factor 23 (FGF23) in 2000 (1), our understanding of the mechanisms of phosphate homeostasis and of bone mineralization has grown exponentially. FGF23 is the link between intestine, bone, and kidney together in phosphate regulation. However, we still do not know the complex mechanism of phosphate homeostasis and bone mineralization. The physiological role of FGF23 is to regulate serum phosphate. Secreted mainly by osteocytes and osteoblasts in the skeleton (2,3), it modulates kidney handling of phosphate reabsorption and calcitriol production. Genetic and acquired abnormalities in FGF23 structure and metabolism cause conditions of either hyper-FGF23 or hypo-FGF23. Hyper-FGF23 is related to hypophosphatemia, while hypo-FGF23 is related to hyperphosphatemia. Both hyper-FGF23 and hypo-FGF23 are detrimental to humans. In this review, we will discuss the pathophysiology of FGF23 and hyper-FGF23 related renal phosphate wasting disorders (4).

[Variation characteristics and calculation model of evapotranspiration in latored soils on hills].

The dynamic characteristics of evapotranspiration in latored soil on hills of subtropics regions in south China was analyzed. The results showed that evapotranspiration presented annual and seasonal fluctuations. The maximum monthly evapotranspiration was 10.80-15.41 times of the monthly minimum. The evapotranspiration in wet season (March to September) accounted for about 77% of annual total evapotranspiration, and that in dry season (October to February of next year) accounted for about 23%. Although the amount of annual rainfalls could balance annual total evapotranspiration, rainfalls were insufficient for evapotranspiration in the dry season, and soil water could be depleted by evapotranspiration. Based on the modified Penman equation, the calculation model of evapotranspiration in latored soil on hills of subtropics regions in south China was set up. By comparing modeling results with experimental data, it was proved that the calculation model was very reliable.