The interaction between TMEM161B (rs768705) and paranoid personality traits in relation to the risk of major depressive disorder: Results form a longitudinal study of 7642 Chinese freshmen.

BACKGROUND: Rs768705 (TMEM161B) is one of the identified single nucleotide polymorphisms related to major depressive disorder (MDD). Paranoid personality traits are independently associated with the risk of MDD. This study aimed to investigate the interaction effect between rs768705 (TMEM161B) and paranoid personality traits on the new-onset risk of MDD in Chinese freshmen. METHODS: A longitudinal study was conducted among 7642 Chinese freshmen without lifetime MDD at baseline in 2018. 158 new-onset MDD cases were ascertained in 2019. DNA samples were extracted to detect the genotype of rs768705. The diagnostic and statistical manual of mental disorders-IV criteria were used to determine MDD and personality disorder traits. Multiplicative interaction was assessed by logistic regression models. Tomas Andersson's method for calculating biological interactions was used to estimate the additive interaction. RESULTS: Rs768705(AG) (OR = 1.88, 95 % CI: 1.24-2.83) and paranoid personality traits (OR = 3.68, 95 % CI: 2.57-5.26) were significantly associated with the risk of MDD. The multiplicative interaction model with the product term of rs768705 and paranoid personality trait traits had a significant interaction effect (OR = 4.20, 95 % CI:1.62-10.91). There was also a significant additive interaction effect (RR = 7.08, 95 % CI:4.31-11.65) for the incidence of MDD. Seventy seven percent patients among new MDD cases were attributed to the additive interaction effect between rs768705 and paranoid personality traits. CONCLUSIONS: Rs768705 (AG) may interact with paranoid personality traits to increase the incidence of MDD among Chinese college students. Schools and psychosocial health organizations should pay more attention to individuals with paranoid personality traits for MDD intervention and prevention.

Associations Between Psychological Stress and the Risk of First Onset of Major Depression Disorder: Results from a Longitudinal Study in 6,985 Chinese First-Year Students.

Background: Youth and young adults have a high prevalence of major depressive disorder (MDD). Limited longitudinal research has explored the relationship between different dimensions of psychological stress and MDD. This study aimed to estimate the effect of psychological stress on the risk of first onset MDD in a sample of Chinese freshmen. Methods: Using a longitudinal design, 8079 Chinese first-year students were recruited at baseline, and 6985 were followed up one year later. The Psychological Stress Scale for College Students was utilized to evaluate the levels of psychological stress. MDD was evaluated using the Chinese version of the Composite International Diagnostic Interview (CIDI-3.0). Logistic regression modeling was utilized to estimate the associations between dimensions of psychological stress and the risk of MDD. Results: Two dimensions of psychological stress, namely learning stress (OR=1.05, 95% CI:1.01-1.09, P=0.017) and economic stress (OR=1.11, 95% CI:1.04-1.19, P=0.001), were significantly associated with the risk of MDD. Other dimensions of psychological stress (specify family stress, interpersonal stress, intimate relationship stress, employment stress and appearance stress) were not associated with MDD. Conclusion: Psychological stress, especially learning and economic stresses, could increase the risk of MDD in university students. These factors should be incorporated into mental health prevention and intervention programs at universities to reduce the risks of MDD.

The mediating effects of dysfunctional attitudes and moderating effect of sex between stressful life events and depressive symptoms among Chinese college students.

Stressful life events (SLEs) closely correlates with depressive symptoms. Although vulnerability-stress model suggests SLEs interacted with dysfunctional attitudes (DA) to predict depression, the mediation role of DA is poorly understood. Therefore, this study intended to investigate the mediating role of DA and the moderating role of sex between SLEs and self-reported depression. A cross-sectional survey was conducted with a sample of 7769 Chinese college students. Participants were assessed in terms of self-reported SLEs, DA and depression variables. Results showed that there were significant sex differences in both SLE and DA. DA mediated the association between SLE and self-reported depression. The moderated mediation model analysis showed that the interaction of SLEs and sex significantly predicted DA in mediator variable model and self-reported depression in dependent variable model. Results indicated that DA partially mediated the association between SLEs and self-reported depression, and sex moderates the association between SLEs and both DA and self-reported depression, which females have bigger changes of DA and depressive symptoms across low and high levels of SLEs than males.

Influence of PCDH9 (rs9540720) and narcissistic personality traits on the incidence of major depressive disorder in Chinese first-year university students: findings from a 2-year cohort study.

Objective: The objective of this study was to explore the influence of the polymorphism of the protocadherin 9 (PCDH9) gene and the narcissistic personality trait (NPT) on the risk of major depressive disorder (MDD) in Chinese first-year university students. Methods: A 2-year cohort study was conducted among Chinese first-year university students who were enrolled in 2018 from two universities in Shandong Province, China. The snapshot technique was used to detect the genotypes of PCDH9 (rs9540720). The Chinese version of the Composite International Diagnostic Interview was used for the MDD assessment. The NPTs were measured by 11 items based on DSM-IV. Patient Health Questionnaire-9 and the Beck Anxiety Inventory were used to assess depressive and anxiety symptoms, respectively. Logistic regression modeling was carried out to examine the relationship between rs9540720, NPTs, and the incidence of MDD. Results: A total of 5,327 students participated in the baseline and follow-up studies and provided their blood samples. PCDH9 (rs9540720) (ORGG+GA = 2.33, 95% CI: 1.35-4.02) and NPTs (OR5-9 = 2.26, 95% CI: 1.40-3.64) increased the risk of MDD onset. There was no multiplicative interaction between NPTs and Rs9540720 (OR = 1.51, 95% CI: 0.30-7.63). Furthermore, there was no additive interaction between them (RERI = 2.40, 95% CI: -0.82-5.62; AP = 0.47, 95% CI: -0.04-0.97; and S = 2.37, 95% CI: 0.54-10.33). Conclusion: PCDH9 (rs9540720) and more NPTs are the risk factors for the incidence of MDD in Chinese first-year university students.

Identification and characterization of leucocyclicin Q, a novel cyclic bacteriocin produced by Leuconostoc mesenteroides TK41401.

The culture supernatant of Leuconostoc mesenteroides TK41401, isolated from Japanese pickles, possessed antimicrobial activity against broad range of a bacterial genera and particularly strong activity against Bacillus coagulans, the major contaminant of pickles. An antimicrobial peptide was purified in three chromatographic steps, and its molecular mass was determined to be 6,115.59 Da by electrospray ionization time-of-flight mass spectrometry (ESI-TOF MS). The primary structure of this peptide was determined by amino acid and DNA sequencing, and these analyses revealed that it was translated as a 63-residue precursor. This precursor showed high similarity to the precursor of lactocyclicin Q, a cyclic bacteriocin produced by Lactococcus sp. strain QU 12. The molecular weight calculated after cyclization, which was presumed to involve the same process as in lactocyclicin Q (between L3 and W63), agreed with that estimated by ESI-TOF MS. This peptide was proved to be a novel cyclic bacteriocin, and it was termed leucocyclicin Q. The antimicrobial spectrum of this bacteriocin clearly differed from that of lactocyclicin Q, even though their primary structures were quite similar. This is the first report of a cyclic bacteriocin produced by a strain of the genus Leuconostoc.

Biological function of a DUF95 superfamily protein involved in the biosynthesis of a circular bacteriocin, leucocyclicin Q.

Biological functions of a DUF95 superfamily protein in the biosynthesis gene cluster of a novel circular bacteriocin, leucocyclicin Q (LcyQ), were characterized in this paper. Sequence analysis and database search of the regions flanking the LcyQ structural gene lcyQ revealed four open reading frames (lcyR, lcyB, lcyC, and lcyD) related to bacteriocin biosynthesis. LcyD shares some similarity to the DUF95 superfamily proteins, often found in the biosynthetic gene clusters of circular bacteriocins. Mass spectrometry analysis showed accumulation of active mature LcyQ inside lcyD knockout cells. Heterologous expression of lcyD demonstrated that it confers robust immunity against LcyQ. Peptide release/binding assay revealed that the immunity could be attributed to the secretion of LcyQ to the cell exterior. Thus, the DUF95 superfamily protein has a dual function in the biosynthesis of LcyQ, as an immunity-associated transporter and as a secretion-aiding agent. Accumulation of mature LcyQ inside the cell in lcyD knockout strains, further implied that cyclization occurs within the cell. To the best of our knowledge, this is the first report on LcyQ cyclization inside the cell and the dual role of a DUF95 superfamily protein in circular bacteriocin biosynthesis.