[Gender differences of genetic etiology in the incidence of major depressive disorder among Han freshmen].

Objective: To analyze the gender differences of genetic etiology in the incidence of major depression disorder among Han freshmen. Methods: A 1-year follow-up survey was carried out among 8 079 Han freshmen from Jining, Rizhao and Weifang without lifetime major depressive disorder (MDD) at baseline (April to October 2018) and 4 828 venous blood samples were also collected. After extracting DNA, Sequenom Mass Array time-of-flight mass spectrometry biochip technology was used to detect the genotypes of 17 single nucleotide polymorphisms (SNPs) MDD-related loci. Logistic regression was used for univariate analysis. Generalized multifactor dimension reduction was used to analyze gene-gene interactions. Composite International Diagnostic Interview (CIDI) 3.0 was used for MDD diagnosis. Results: The 1-year incidence of MDD among Han freshmen was 2.23% (95%CI: 1.91%-2.60%) and the gender difference of incidence between males (1.97%, 95%CI: 1.52%-2.56%) and females (2.39%, 95%CI: 1.98%-2.90%) was not statistically significant (P>0.05). AG genotype of rs768705 (nearby gene: TMEM161B) was a risk factor for MDD (OR=1.98, 95%CI: 1.24-2.83). The TC genotype of rs17727765 (nearby gene: CRYBA1) was only a risk factor for MDD in males (OR=9.61, 95%CI: 2.04-45.30). An 8-loci interaction model (PMFBP1, OLFM4, LHPP, ENOX1, TMEM161B, SPPL3, FBXL4 and L3MBTL2) could predict MDD in women with an accuracy rate of 60.05%. No effective prediction model was found for MDD in men. Conclusions: There might be gender differences in the genetic etiology of MDD. Further researches on the genetic causes of MDD in men should be explored.

Assembly of the native heterodimer of Rana esculenta tropomyosin by chain exchange.

Rana esculenta tropomyosin assembles in vivo into a coiled-coil alpha helix from two different subunits, alpha and beta, which are present in about equal concentrations. Although the native composition is alpha beta, a mixture of equal amounts of alpha alpha and beta beta is produced by refolding dissociated alpha and beta at low temperature in vitro. Refolding kinetics showed that alpha alpha formed first and was relatively stable with regard to chain exchange below approximately 20 degrees C. Equilibration of the homodimer mixture at 30 degrees and 34 degrees C for long times, however, resulted in the formation of the native alpha beta molecule by chain exchange. Biosynthesis of alpha beta from separate alpha and beta genes is, therefore, favored thermodynamically over the formation of homodimers, and biological factors need not be invoked to explain the preferred native alpha beta composition.

Saccharopolyspora spinosporotrichia sp. nov., a novel actinomycete from soil.

The generic position of an aerobic, Gram-positive, non-acid-alcohol-fast actinomycete was determined following isolation of the PCR-amplified 16S rRNA genes and alignment of the resultant sequence with corresponding sequences from representatives of the family Pseudonocardiaceae. The assignment of the organism to the genus Saccharopolyspora was strongly supported by chemotaxonomic and morphological data. The strain was distinguished from representatives of validly described Saccharopolyspora species by a number of phenotypic properties. It is proposed that the organism, strain AS4.198T, be classified in the genus Saccharopolyspora as Saccharopolyspora spinosporotrichia sp. nov.