Fast and furious: Early differences in growth rate drive short-term plant dominance and exclusion under eutrophication.

The reduction of plant diversity following eutrophication threatens many ecosystems worldwide. Yet, the mechanisms by which species are lost following nutrient enrichment are still not completely understood, nor are the details of when such mechanisms act during the growing season, which hampers understanding and the development of mitigation strategies.Using a common garden competition experiment, we found that early-season differences in growth rates among five perennial grass species measured in monoculture predicted short-term competitive dominance in pairwise combinations and that the proportion of variance explained was particularly greater under a fertilization treatment.We also examined the role of early-season growth rate in determining the outcome of competition along an experimental nutrient gradient in an alpine meadow. Early differences in growth rate between species predicted short-term competitive dominance under both ambient and fertilized conditions and competitive exclusion under fertilized conditions.The results of these two studies suggest that plant species growing faster during the early stage of the growing season gain a competitive advantage over species that initially grow more slowly, and that this advantage is magnified under fertilization. This finding is consistent with the theory of asymmetric competition for light in which fast-growing species can intercept incident light and hence outcompete and exclude slower-growing (and hence shorter) species. We predict that the current chronic nutrient inputs into many terrestrial ecosystems worldwide will reduce plant diversity and maintain a low biodiversity state by continuously favoring fast-growing species. Biodiversity management strategies should focus on controlling nutrient inputs and reducing the growth of fast-growing species early in the season.

Factors influencing utilization of primary health care by elderly internal migrants in China: the role of social contacts.

BACKGROUND: Utilization of primary health care is an important aspect of elderly internal migrants' access to screening and preventive services in China. It has been evident that social contacts, such as community engagement, social mobilization, and the ability to communicate were related to health service delivery, but little has been done to explore the relationship between social contacts and utilization of primary health care for this group. This study aimed to explore the factors influencing utilization of primary health care from the perspective of social contacts among elderly internal migrants in China. METHODS: This was a cross-sectional study including 1544 elderly internal migrants in eight cities. Whether these indivdiuals had chosen to participate in the free health checkup organized in the previous year was adopted as an indicator of the utilization of primary health care. The number of local friends and amount of exercise time per day were measured as a proxy for social contacts. Multivariate binary logistic regression was used to investigate the association of social contacts with the likelihood of using primary health care. RESULTS: 55.6% of the respondents were men, and the mean age was 66.34 years (SD, 5.94). 88.6% had received an education of high school or below. 12.9% had no local friends. 5.2% did not exercise. Just 33.1% had participated in a free medical check-up. Social contacts, age, and medical insurance were associated with more use of primary health care among elderly internal migrants in China. CONCLUSION: The role of the community in promoting the use of primary health care should be expanded, such as creating community-based campaigns specifically targeting elderly internal migrants or designing social or sports activities tailored to increase the opportunity for contact between local elders and their internal migrant peers.

MicroRNA-200c and microRNA- 141 are regulated by a FOXP3-KAT2B axis and associated with tumor metastasis in breast cancer.

BACKGROUND: Members of the microRNA (miR)-200 family, which are involved in tumor metastasis, have potential as cancer biomarkers, but their regulatory mechanisms remain elusive. METHODS: We investigated FOXP3-inducible breast cancer cells, Foxp3 heterozygous Scurfy mutant (Foxp3 sf/+ ) female mice, and patients with breast cancer for characterization of the formation and regulation of the miR-200 family in breast cancer cells and circulation. Participants (259), including patients with breast cancer or benign breast tumors, members of breast cancer families, and healthy controls, were assessed for tumor and circulating levels of the miR-200 family. RESULTS: First, we identified a FOXP3-KAT2B-miR-200c/141 axis in breast cancer cells. Second, aging Foxp3 sf/+ female mice developed spontaneous breast cancers and lung metastases. Levels of miR-200c and miR-141 were lower in Foxp3 sf/+ tumor cells than in normal breast epithelial cells, but plasma levels of miR-200c and miR-141 in the Foxp3 sf/+ mice increased during tumor progression and metastasis. Third, in patients with breast cancer, the levels of miR-200c and 141 were lower in FOXP3 low relative to those with FOXP3 high breast cancer cells, especially in late-stage and metastatic cancer cells. The levels of miR-200c and miR-141 were higher in plasma from patients with metastatic breast cancer than in plasma from those with localized breast cancer, with benign breast tumors, with a family history of breast cancer, or from healthy controls. Finally, in Foxp3 sf/+ mice, plasma miR-200c and miR-141 appeared to be released from tumor cells. CONCLUSIONS: miR-200c and miR-141 are regulated by a FOXP3-KAT2B axis in breast cancer cells, and circulating levels of miR-200c and miR-141 are potential biomarkers for early detection of breast cancer metastases.

CD24 is a genetic modifier for risk and progression of prostate cancer.

CD24 plays an oncogenic role in the onset and progression of various human cancers, including prostate cancer. In the present study, we identified two linkage disequilibrium blocks with four recombination hotspot motifs in human CD24 locus. To elucidate whether genetic variants of CD24 are associated with susceptibility to prostate cancer and its disease status, we conducted a case-control association study with two P170 C/T and P-534 A/C polymorphisms of CD24 in 590 patients with prostate cancer and 590 healthy controls. A significant increased risk of prostate cancer was found in men with the P170T/T genotype over the P170C/C genotype (odd ratio = 1.74, 95% confidence interval = 1.16-2.63, P = 0.008), and in men with the P-534C/C genotype over the P-534A/A genotype (odd ratio = 1.47, 95% CI = 1.18-2.26, P = 0.003). Cochran-Armitage trend analysis showed that the P170T allele was significantly correlated with an increased risk of prostate cancer progression (P = 0.029, trend between genotypes and stages) and this observation was also validated in an independent sample cohort. Next, we found that tumors with P170T or P-534C alleles had more twofold increased protein expressions of CD24 as compared to those with P170C or P-534A alleles, respectively. Likewise, tumors with a combination of P170T/T and P-534C/C genotypes were associated with a high mRNA level of CD24. Our data suggest a significant association of CD24 genetic variants with prostate cancer onset and progression, which provides new insight into molecular genetics of prostate cancer; however, these findings need to be validated in multiple independent cohorts. © 2016 Wiley Periodicals, Inc.

Association study of 45 candidate genes in nicotine dependence in Han Chinese.

Numerous genetic linkages, association studies have been performed in different ethnic groups and revealed many susceptibility loci and genes for nicotine dependence. However, limited similar researches were performed in Han Chinese. This study was designed to investigate the association of candidate genes with nicotine dependence in Han Chinese. We genotyped 384 SNPs within 45 candidate genes with nicotine dependence in a Han Chinese population consisting 223 high nicotine dependent subjects and 257 low nicotine dependent subjects by employing GoldenGate genotyping assay (Illumina). Following association analysis was performed using PLINK software. Individual SNP-based association analysis revealed that nine SNPs located in DRD3 (rs2630351), DRD5 (rs1967550), MAP3K4 (rs2314378), DDC (rs11575461), CHRNB3 (rs4954), GABBR2 (rs2779562), DRD2 (rs11214613 and rs6589377) and CHRNA4 (rs2236196) were significantly associated with FTND after correction for multiple testing with the p values from 2.59×10(-7) to 9.99×10(-5). Haplotype-based association analysis revealed haplotype G-A-A formed by rs2630351, rs167771 and rs324032 and haplotype G-G-G-A formed by rs3773678, rs2630349, rs2630351 and rs167771 in DRD3; haplotype of G-A formed by rs2779562 and rs2808566 in GABBR2 and haplotype of T-T-A-G-A formed by rs6832644, rs4057797, rs9764, rs4552421 and rs10033119 in NPY1R are associated with FTND (p=3.61×10(-7)-8.78×10(-6)). Our results provided confirmation of the previous findings that DRD2, DRD3, DDC, CHRNB3, GABBR2 and CHRNA4 are associated with nicotine dependence. Furthermore, we for the first time report a significant association between nicotine dependence and DRD5, MAP3K4 and NPY1R. These findings need independent replication in the future studies.

Association of nicotinic acetylcholine receptor subunit alpha-4 polymorphisms with smoking behaviors in Chinese male smokers.

BACKGROUND: It has been reported that the nicotinic acetylcholine receptor subunit α4 gene (CHRNA4) might be associated with smoking behaviors in the previous studies. Up to now, there are few reports on the relationship between CHRNA4 and smoking initiation. In this study, we tried to explore the role of two polymorphisms in CHRNA4 (rs1044396 and rs1044397) in smoking initiation and nicotine dependence in Chinese male smokers. METHODS: Nine hundred and sixty-six Chinese male lifetime nonsmokers and smokers were assessed by the Fagerström test for nicotine dependence (FTND), smoking quantity (SQ) and the heaviness of smoking index (HSI). All subjects were divided into four groups based on their tobacco use history and the FTND scores. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed to find two polymorphisms of CHRNA4 in these subjects. RESULTS: The χ(2) test showed that rs1044396 was significantly associated with smoking initiation (χ(2) = 4.65, P = 0.031), while both rs1044396 and rs1044397 were significantly associated with nicotine dependence (χ(2) = 5.42, P = 0.020; χ(2) = 7.58, P = 0.005). Furthermore, the T-G (3.9%) haplotype of rs1044396-rs1044397 showed significant association with smoking initiation (χ(2) = 6.30, P = 0.012) and the C-G haplotype (58.9%) remained positive association with nicotine dependence (χ(2) = 8.64, P = 0.003) after Bonferroni correction. The C-G haplotype also significantly increased the HSI (P = 0.002) and FTND scores (P = 0.001) after Bonferroni correction. CONCLUSION: These findings suggest that CHRNA4 may be associated with smoking initiation and the C-G haplotype of rs1044396-rs1044397 might increase the vulnerability to nicotine dependence in Chinese male smokers.

[Relationship between lung injury induced by hemorrhagic shock/reperfusion and nitric oxide and beneficial effect of taurine].

AIM: To approach the relationship between lung injury induced by shock/reperfusion and nitric oxide as well as the beneficial effect of taurine. METHODS: Twenty four rabbits were divided randomly into 3 groups (n = 8): control group, shock group, taurine group. The model of lung injury induced by shock/reperfusion was used. The activities of nitric oxide synthase (NOS), superoxide dismutase (SOD), the contents of malondialdehyde (MDA), nitric oxide products (NO2-/NO3-) in plasma and lung homogenate, lung wet/dry weight, lung water content, lung permeability index, and protein content in the pulmonary alveolar lavage fluid were measured. Meanwhile, pathologic samples treated routinely. RESULTS: (1) At 3 hours after reperfusion, the activities of SOD in plasma and lung homogenate decreased markedly, but the other indexes above mentioned were increased significantly compared with the control group (P < 0.01). (2) A close correlation was shown between MDA content and NO2-/NO3- content in plasma and lung. Furthermore, the content of NO2-/NQ3- in lung homogenate showed strong positive correlation with the lung injury parameters. (3) Taurine (40 mg x kg(-1) i.v.) could attenuate all the changes above mentioned at the same time points of reperfusion. CONCLUSION: NO may play an important role in lung injury induced by shock/reperfusion. Taurine can ameliorate the lung injury, mechanism of which may be related to decreasing the generation of NO and anti-lipoperoxidation.

[Effects of taurine on NOS activity in myocardium and plasma of hemorrhagic shock resuscitation in rabbits].

AIM: To investigate the effect of taurine on nitric oxide synthase (NOS) activity and nitric oxide products (NO2 /NO3 ) content in myocardium and plasma during shock resuscitation. METHODS: Twenty-four rabbits were divided randomly into 3 groups (n=8): control group, shock group, taurine group. The model of hemorrhagic shock resuscitation was used. The activities of nitric oxide synthase (NOS), lactate dehydrogenase (LDH) and the contents of nitric oxide products (NO2- /NO3-) in plasma were observed before shock and shock 1.5 hours, after resuscitation 1 hour, 2 hours and 3 hours. The activities of NOS and the contents of NO2-/NO3- in myocardium homogenate were measured after resuscitation 3 hours. Meanwhile, pathologic samples treated routinely. RESULTS: (1) During resuscitation, the activities of NOS, LDH and the contents of NO2- /NO3- in plasma of shock group were significantly higher than that of before shock and shock 1.5 hours (P < 0.01). (2) After resuscitation 3 hours, the activity of NOS and the contents of NO2- / NO3 in myocardium of shock group were significantly higher than that of control group (P < 0.01). The cardiac myocyte appeared edema, fatty degeneration. (3) All the changes of above mentioned could be attenuated by intravenous injection taurine (40 mg/kg) (P < 0.01). CONCLUSION: These results suggest that the NOS activation and NO release may mediated myocardium injury induced by shock resuscitation, taurine can ameliorate the myocardium injury, which may be related to decreasing the generation of NO.