[Comparison of Soil Bacterial Community Structure Between Paddy Fields and Dry Land in the Huixian Karst Wetland, China].

In order to explore the effect of land-use change on soil bacteria in wetland systems, the topsoil (0-20 cm) of a natural wetland (NW), paddy field (PF), and dry land (DL) were collected in the Huixian karst wetland. The α-diversity, species composition, and abundance of soil bacterial communities were analyzed using high-throughput sequencing. The effect of environmental factors on bacterial community structure was also examined. The results showed that the soil bacteria in the Huixian karst wetland can be divided into 49 phyla and 145 classes. The Shannon index of bacteria in the PF was significantly higher, and the Simpson index of bacteria in the NW is significantly lower, than in the other two land-use types. The dominant phyla (operational taxonomic units, OTUs>1%) in the NW were Proteobacteria (52.15%), Actinobacteria (15.16%), and Acidobacteria (8.80%); the dominant phyla in the PF were Proteobacteria (45.79%), Acidobacteria (17.20%), and Chloroflexi (11.75%); the dominant phyla in the DL were Proteus (51.42%), Acidobacteria (15.51%), and Chloroflexi (7.43%). The dominant classes (OTUs>1%) in the NW were α-Proteobacteria (17.98%), ß-Proteobacteria (13.72%), and Actinobacteria (13.13%); the dominant classes in the PF were Acidobacteria (14.35%), ß-Proteobacteria (13.37%), and δ-Proteobacteria (12.02%); the dominant classes in the DL were α-Proteobacteria (19.44%), Formobacteria (13.30%), and Acidobacteria (13.03%). Among the dominant OTUs (>0.3%), the dominant genera of in the NW were Sphingomonas (OTU2, 59), Micromonospora (OTU5, 24 and 50487), Gemmatimonas (OTU1), and Tenotrophomonas (OTU8); the dominant genera in the PF were Lysobacter (OTU4 and 115) and Aquabacterium (OTU33); the dominant genera in the DL were Sphingomonas (OTU85, 157 and 2916), Rhodanobacter (OTU19 and 52), and Penlobacterium (OTU60). A heatmap showed that there were significant differences in soil bacterial community structure among the three land-use types. Redundancy analysis showed that pH, soil organic carbon (SOC), total nitrogen (TN), alkali-hydrolyzable nitrogen (AN), exchangeable Mg2+, exchangeable Ca2+, soluble organic carbon (DOC), and available phosphorus (AP) were the main factors that affected the bacterial community structure in the Huixian karst wetland. These results indicate that changes in land-use types have significantly shaped the structure of soil bacterial communities in this area.

Interaction Study of Ferrocene Derivatives and Heme by UV-Vis Spectroscopy.

The interaction between ferrocene derivatives, such as Fc(COOH)2(λmax=286 nm), Fc(OBt)2(λmax=305 nm), Fc(Cys)(λmax=289 nm) and heme(λmax=386 nm) were studied by UV-Vis spectroscopy, respectively. The results show that, when the concentration of heme is fixed, the absorbance of heme increases with the increase of Fc(COOH)2 and Fc(Cys) concentration, the absorbance of heme almost keep the same when Fc(OBt)2 concentration increases; when the concentration of ferrocene derivatives are fixed, the absorbance of Fc(COOH)2 and Fc(Cys) also increases with the increase of heme concentration, the absorbance of Fc(OBt)2 almost keep the same when heme concentration increase. It is demonstrated that the hydrogen bonding interactions happen between Fc(COOH)2, Fc(Cys) and heme, none of Fc(OBt)2, the formation of hydrogen bonding lead to the growth of molecular chain, the bigger molecule can absorb more energy and increase the absorbance. Meanwhile, the stability of molecule is affected by the formation of hydrogen bonding, when the reaction time increases from 0.5 h to 18 h and 48 h, the absorbance at λmax=384 nm change from 2.64 to 2.53 and 2.51 with fixed concentration of Fc(COOH)2, the absorbance at λmax=384 nm change from 1.76 to 1.72 and 1.68 with fixed concentration of heme, the absorbance at λmax=397 nm change from 2.74 to 2.63 and 2.55 with fixed concentration of Fc(Cys), and the absorbance at λmax=397 nm change from 1.82 to 1.58 and 1.49 with fixed concentration of heme, respectively.

[Value of basal serum gonadotropin levels in the diagnosis of precocious puberty in girls].

OBJECTIVE: To study the value of basal serum gonadotropin levels in the diagnosis of precocious puberty (PP) in girls. METHODS: A total of 77 girls with PP were divided into central PP (CPP) (n=45) and isolated premature thelarche (IPT) groups (n=32) based on the results of gonadotropin releasing hormone (GnRH) stimulation test, which was considered the gold standard for diagnosis of PP. The two groups were compared with respect to basal serum luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels and LH/FSH ratio. The receiver operating characteristic (ROC) curve was used to analyze the accuracy of basal LH and FSH levels and LH/FSH ratio in the diagnosis of PP. RESULTS: The basal serum LH and FSH levels and LH/FSH ratio in the CPP group were significantly higher than in the IPT group (P<0.01). The basal serum LH level was positively correlated with peak LH level in the GnRH stimulation test in both groups. For diagnosis of CPP, the area under the ROC curve (AUC) for basal serum LH level was larger than for basal serum FSH level and LH/FSH ratio (P<0.05), and there was no significant difference in the AUC value between basal serum FSH level and LH/FSH ratio. When the basal serum LH level was 0.62 IU/L, there was a maximum Youden index (0.684), with 77.8% sensitivity and 90.6% specificity. When the basal serum LH level reached 1.5 IU/L, the sensitivity decreased to 31.1%, but with the highest specificity (100%). CONCLUSIONS: Basal serum LH level is superior to LH/FSH ratio and basal serum FSH level in the diagnosis of CPP, and can be used for preliminary diagnosis of PP in girls in the out-patient department, but there is some misdiagnosis and missed diagnosis. When basal serum LH level is higher than 1.5 IU/L the diagnosis of CPP can be confirmed in combination with clinical manifestation, without the need for an additional GnRH stimulation test.