Promoting the denitrification process by heavy metals in Liaohe Estuary sediment.

The impact of heavy metal ions on the biodenitrification process remains unknown, which is the key to understand the nitrogen cycle in estuarine areas. Here, denitrification rate and the abundance of five denitrifying enzyme genes (narG, nirK, napA, norB and nosZ) in Liaohe Estuary sediments were examined, and the community structure of nirK denitrifying bacteria was also analyzed. The results demonstrate a significant positive correlation between heavy metal content (Cu2+, Zn2+, and Cr) and the denitrification rate, and the abundance of napA/norB (periplasmic nitrate reductase and nitric-oxide reductase) in sediments. The dominant narG denitrifiers were Pseudomonas, Hydrogenophaga, and Serratia known to be tolerant to heavy metal pollution. Sediment particle size, NO3-, NO2-, Zn2+, and Cd2+ were the key factors influencing the denitrifying community structure. These findings suggest that heavy metals may enhance the aerobic denitrification process in sediments and mitigate the adverse effects of high dissolved oxygen levels.

Clinical features and treatment outcome of four patients with Kallmann syndrome caused by fibroblast growth factor receptor-1 gene mutation / 中华内分泌代谢杂志

Objective:To investigate the clinical features and treatment outcome of Kallmann syndrome(KS) caused by fibroblast growth factor receptor-1(FGFR1) gene mutation in 4 patients.Methods:Targeted next-generation sequencing(NGS) was performed on thirty KS and normosmic idiopathic hypogonadotropic hypogonadism(nIHH) patients. FGFR1 mutation was identified in four KS patients. The clinical data, laboratory and imaging examinations, and treatment outcome were retrospectively analyzed.Results:Four male patients, aging from 11 to 22 years old, presented as micropenis, and with olfactory dysfunction. Among them, two had history of cryptorchidism, three had history of cleft lip and palate repair surgery. The most severe patient presented with short stature, left microtia and dental agenesis. FGFR1 heterozygous mutation was identified in all four patients, two were point mutation(p.Y374X; p. E670K), and the other was frameshift mutation(p.S346Yfs*61; p.S723*fs*1). One patient, who started treatment of the pulsatile GnRH pump during his youth, succeeded in having two babies.Conclusion:Patients with Kallmann syndrome caused by FGFR1 mutation presents complex clinical manifestations. Besides dysosmia, micropenis, microrchidia, and delayed pubertal development are the main clinical manifestations in male patients. Symptoms such as cleft lip and palate are helpful for early recognition. Genotyping analysis is crucial to confirm the diagnosis. The pulsatile GnRH pump can produce satisfactory therapeutic effect, but the age of initiating therapy should be carefully considered.