Promoting the Growth of Pinus sylvestris var. mongolica Seedlings and Improving Rhizosphere Fungal Community Structure through Interaction between Trichoderma and Ectomycorrhizal Fungi

In this study, pot experiments were conducted on the seedlings of Pinus sylvestris var. mongolica to study the influence of Trichoderma (Trichoderma harzianum E15) and Ectomycorrhizal fungi (Suillus luteus N94) on the growth of these seedlings. In particular, the effects of these fungi on the fungal community structure in the rhizosphere soil of the seedlings were investigated. Inoculation with Trichoderma harzianum E15 and Suillus luteus N94 significantly (P < 0.05) promoted the growth of the Pinus sylvestris seedlings. The non-metric multidimensional scaling (NMDS) results indicated a significant difference (P < 0.05) between the fungal community structures in the rhizosphere soil of the annual and biennial seedlings. In the rhizosphere soil of annual seedlings, the main fungi were Ascomycota, Basidiomycota, Zygomycota. Ascomycota, Basidiomycota, Mortierellomycota, and p-unclassified-k-Fungi were the main fungi in the rhizosphere soil of biennial seedlings. The dominant genus in the rhizosphere soil and a key factor promoting the growth of the annual and the biennial seedlings was Trichoderma, Suillus, respectively. Both of them were negatively correlated with the relative abundance of microbial flora in the symbiotic environment. Trichoderma had a significant promoting effect on the conversion of total phosphorus, total nitrogen, ammonium nitrogen, nitrate nitrogen, and the organic matter in the rhizosphere soil of the seedlings, while Suillus significantly promoted the conversion of organic matter and total phosphorus

Application of 4-way decomposition to the analysis of placental-fetal biomarkers as intermediary variables between maternal body mass index and birthweight

Human chorionic gonadotropin (hCG) is a placental hormone measured in pregnancy to predict individual level risk of fetal aneuploidy and other complications; yet may be useful in understanding placental origins of child development more generally. hCG was associated with maternal body mass index (BMI) and with birthweight. The primary aim here was to evaluate hCG as a mediator of maternal BMI effects on birthweight by causal mediation analysis. Subjects were 356 women from 3 U.S. sites (2010–2013). The 4-way decomposition method using med4way (STATA) was applied to screen for 5 types of effects of first trimester maternal BMI on birthweight: the total effect, the direct effect, mediation by hCG, additive interaction of BMI and hCG, and mediation in the presence of an additive interaction. Effect modification by fetal sex was evaluated, and a sensitivity analysis was performed to evaluate the assumption of unmeasured confounding. Additional placental-fetal biomarkers [pregnancy associated plasma protein A (PAPPA), second trimester hCG, inhibin-A, estriol, alpha fetoprotein] were analyzed for comparison. For first trimester hCG, there was a 0.20 standard deviation increase in birthweight at the 75th vs. 25th percentile of maternal BMI (95% CI 0.04, 0.36). Once stratified, the direct effect association was null in women carrying females. In women carrying males, hCG did not mediate the relationship. In women carrying females, there was a mediated effect of maternal BMI on birthweight by hCG in the reverse direction (−0.06, 95% CI: −0.12, 0.01), and a mediated interaction in the positive direction (0.06, 95% CI 0.00, 0.13). In women carrying males, the maternal BMI effect on birthweight was reverse mediated by PAPPA (−0.09, 95% CI: −0.17, 0.00). Sex-specific mediation was mostly present in the first trimester. Second trimester AFP was a positive mediator of maternal BMI effects in male infants only (0.06, 95% CI: −0.01, 0.13). Effect estimates were robust to potential bias due to unmeasured confounders. These findings motivate research to consider first trimester placental biomarkers and sex-specific mechanisms when quantifying the effects of maternal adiposity on fetal growth

Prenatal Phthalate Exposure and Infant Anogenital Distance: infant size adjustment, evaluating phthalate mixture effects, and exposure patterns

Anogenital distance (AGD) is the distance from anus to genitalia. AGD at birth reflects androgen disruption during the fetal period. Phthalates, a group of endocrine-disrupting chemicals that are widely used in plastics, can alter AGD at birth in rodents, and possibly in humans. Prenatal higher phthalate exposure caused shorter AGD in animal studies and this association has also been reported in several epidemiological studies. However, the results are not consistent, which could be due to several reasons. First, most studies adjust for infant size in the model or standardize AGD by infant size. Infant size is highly correlated with AGD and may operate as an intermediate variable in the association between phthalates and AGD. The standard approach of controlling for it in statistical models has not been evaluated analytically or quantitatively. Unmeasured confounders of the mediator-outcome association will create bias when estimating the exposure effect on outcome. Using simulated data, we quantified the bias using the effect decomposition method. We concluded that the direct effect of an exposure is a valid estimate only if the unmeasured confounder of the mediator-outcome association is weak or null. Second, as humans are exposed to multiple phthalates simultaneously, the current approach to assessing risk for individual phthalates may be insufficient. We estimated the mixture effect of phthalates using Bayesian kernel machine regression and found a decreasing trend for the effects of phthalate mixture on AGD in male infants and an increasing trend for female infants. Important contributors to the mixture effect were identified. Third, the longitudinal effects of phthalates over time in pregnancy have not been reported previously. We used group-based trajectory models to identify phthalate exposure patterns during pregnancy. We also explored maternal predictors of specific trajectories and the effect of different trajectories on AGD. Inverse associations were observed between high exposure levels of phthalates and AGD. The first trimester was a critical effect period for di-(2-ethyl-hexyl) phthalate metabolites. This work advances our understanding of phthalate effects on fetal reproductive system development, and future efforts to reduce levels of specific phthalates to protect the fetus and the child

The association between telomere length and risk of breast cancer in Singapore Chinese Health Study

Background: Telomeres are tandemly repeated sequences located at the distal ends of linear chromosomes, which play an important role in maintaining chromosome integrity and cell replication. Although numerous epidemiological studies have examined the association between telomere length and risk of breast cancer, the results are conflicting. In this study, we evaluated the association between telomere length and risk of breast cancer using the data from the Singapore Chinese Health Study, a prospective, population-based study. Methods: Study subjects were 14,306 women aged 45-74 years at enrollment in the Singapore Chinese Health Study. The subjects' information of demographics, lifestyle, and reproductive history was collected at enrollment and blood sample collection. Telomere length was measured using the qPCR method. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for risk of breast cancer associated with telomere length in quintiles were calculated using Cox proportional hazard regression, with adjustment for age at blood collection, level of education, body mass index (BMI), number of live births (0, 1-2, 3-4, or 5+) and age at first live birth (nulliparous, <20, 21-25, 26-30, or 31+ years). Results: Breast cancer risk was increased significantly in association with longer telomere length. Women with the highest quintile of telomere length had a 47% higher risk of breast cancer (HR = 1.47, 95% CI = 0.90-2.38, Ptrend = 0.01) compared with the lowest quintile. The association is apparent in women that were overweight/obese (HR = 2.0, 95% CI 1.02 - 3.91, Ptrend = 0.01); women who had menarche less than 14 years old (HR = 1.56, 95% CI 0.84-2.89, Ptrend = 0.01); women who gave first live birth 26 years old or older (HR = 1.74, 95% CI 0.86-3.54, Ptrend = 0.02); and women who had 3 or more children (HR = 1.64, 95% CI 0.83-3.23, Ptrend = 0.02). Conclusion: Longer telomere length is associated with increased risk of breast cancer in an Asian/Pacific Islander population. This finding could provide a significant benefit to public health, as it could serve as convincing evidence for telomere length measurement as a biomarker in breast cancer prevention and development

Endothelial nitric oxide synthase gene single nucleotide polymorphisms and the risk of hypertension: A meta-analysis involving 63,258 subjects

The endothelial nitric oxide synthase (eNOS) gene plays an important role in regulating vascular tone and blood pressure. Recently, the eNOS G894T and T-786C single nucleotide polymorphisms (SNPs) were intensively studied with regard to their associations with hypertension. However, the results of these studies were inconsistent. Therefore, we conducted the so far largest meta-analysis to better assess the correlations between eNOS SNPs and hypertension. Eligible articles were searched in PubMed, Medline, Embase, Scopus, and CNKI up to April 2016. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to detect any potential associations between eNOS SNPs and the risk of hypertension. A total of 95 case–control studies involving 29,308 hypertension cases and 33,950 healthy controls were analyzed. The overall meta-analysis results showed that eNOS G894T and T-786C SNPs were both significantly associated with the risk of hypertension, the T allele of G894T SNP (G versus T, P < 0.00001, OR = 0.82, 95% CI 0.76–0.89) and C allele of T-786C SNP (T versus C, P = 0.004, OR = 0.92, 95% CI 0.87–0.97) conferred an increased susceptibility to hypertension. Further subgroup analyses yielded similar positive results for G894T SNP in essential hypertension, gestational hypertension, and Asian ethnicity, and that for T-786C SNP in essential hypertension and Asian population. Overall, our findings suggest that eNOS G894T and T-786C SNPs were both significantly correlated with hypertension. Additionally, the T allele of G894T SNP and C allele of T-786C SNP may serve as potential biological markers for hypertension susceptibility in Asians

Effects of Dark Septate Endophytes Strain A024 on Damping-off Biocontrol, Plant Growth and the Rhizosphere Soil Enviroment of Pinus sylvestris var. mongolica Annual Seedlings

Dark septate endophytes (DSEs) exert a vital role in promoting plant growth, improving mineral absorption, biological disease control, and enhancing plant stress resistance. The effects of dark septate endophyte strain, Phialocephala bamuru A024 on damping-off biocontrol, plant development, nutrients within the rhizosphere soil, as well as bacterial communities in the annual seedlings of P. sylvestris var. Mongolica were studied. According to our findings, following P. bamuru A024 inoculation, the damping-off disease morbidity decreased significantly compared with control, some physiological indices such as &beta;-1,3-glucanase, chitinase enzyme activity as well as a soluble protein and proline content in P. sylvestris var. mongolica were elevated under R. solani stress. After inoculation with P. bamuru A024, the biomass in seedlings, nutrients in soil, root structure index, together with activities of soil enzymes were remarkably up-regulated relative to control (p &lt; 0.05). As suggested by the results of high-throughput sequencing, the microbial structure in the rhizosphere soil of the P. sylvestris var. mongolica showed significant differences (p &lt; 0.05) after P. bamuru A024 inoculation compared to control treatment and the rhizosphere soil bacterial community structure after DSE A024 inoculation was positively correlated to the main soil nutrition indices

Effects of Sphaeropsis Blight on Rhizosphere Soil Bacterial Community Structure and Soil Physicochemical Properties of Pinus sylvestris var. mongolica in Zhanggutai, China

Pinus sylvestris var. mongolica is an important tree species for ecological construction and environmental restoration owing to its rapid growth rate and excellent stress resistance. Pinus sylvestris var. mongolica sphaeropsis blight is a widespread disease caused by Sphaeropsis sapinea. This study was focused on non-infected (CK) and infected (SS) Pinus sylvestris var. mongolica plants in Zhanggutai area, Liaoning Province, China. Illumina high-throughput sequencing based on the templates of sequencing-by-synthesis working with reversible terminators is a widely used approach. In the present study, systematic differences in relationships among rhizosphere soil physicochemical properties, bacterial community structure, diverse bacterial genera, and alpha diversity indices between the two categories were evaluated. The current findings are as follows: (1) Shannon&rsquo;s index of SS soil was significantly higher than CK, and it was significantly lower in May than July and September (p &lt; 0.05). (2) Non-metric multidimensional scaling (NMDS) showed a difference in bacterial community structure during May (spring), July (summer), and September. (3) At the phylum level, no significant difference was found in the bacterial genera between CK and SS soil for three seasons; however, at the genus level, there were about 19 different bacterial genera. The correlation studies between 19 different bacterial genera and environmental factors and &alpha;-diversity indicated that bacterial genera of non-infected and infected Pinus sylvestris var. mongolica were distributed differently. The bacterial genera with CK were positively correlated with soil physicochemical properties, while a negative correlation was found for SS. In conclusion, the differences in nutrient and microbial community structure in the rhizosphere soil of Pinus sylvestris var. mongolica are the main causes of shoot blight disease

Inhibitory Mechanism of Trichoderma virens ZT05 on Rhizoctonia solani

Trichoderma is a filamentous fungus that is widely distributed in nature. As a biological control agent of agricultural pests, Trichoderma species have been widely studied in recent years. This study aimed to understand the inhibitory mechanism of Trichoderma virens ZT05 on Rhizoctonia solani through the side-by-side culture of T. virens ZT05 and R. solani. To this end, we investigated the effect of volatile and nonvolatile metabolites of T. virens ZT05 on the mycelium growth and enzyme activity of R. solani and analyzed transcriptome data collected from side-by-side culture. T. virens ZT05 has a significant antagonistic effect against R. solani. The mycelium of T. virens ZT05 spirally wraps around and penetrates the mycelium of R. solani and inhibits the growth of R. solani. The volatile and nonvolatile metabolites of T. virens ZT05 have significant inhibitory effects on the growth of R. solani. The nonvolatile metabolites of T. virens ZT05 significantly affect the mycelium proteins of R. solani, including catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), selenium-dependent glutathione peroxidase (GSH-Px), soluble proteins, and malondialdehyde (MDA). Twenty genes associated with hyperparasitism, including extracellular proteases, oligopeptide transporters, G-protein coupled receptors (GPCRs), chitinases, glucanases, and proteases were found to be upregulated during the antagonistic process between T. virens ZT05 and R. solani. Thirty genes related to antibiosis function, including tetracycline resistance proteins, reductases, the heat shock response, the oxidative stress response, ATP-binding cassette (ABC) efflux transporters, and multidrug resistance transporters, were found to be upregulated during the side-by-side culture of T. virens ZT05 and R. solani. T. virens ZT05 has a significant inhibitory effect on R. solani, and its mechanism of action is associated with hyperparasitism and antibiosis