Cigarette smoking strongly modifies the association of complement factor H variant and the risk of lung cancer

The complement system is an important immunosurveillance mechanism against tumors, and complement factor H (CFH) is a key regulator for activation of the complement system. Expression of complement factor H has been demonstrated in cell lines from several malignancies. In this study we examined the contribution of the single-nucleotide polymorphism (SNP) Try402His (Y402H) (rs1061170) in the CFH gene to the risk of lung cancer in a case-control study with 1000 cases and 1000 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were computed by logistic regression. The frequencies for CFH Y402H genotypes among the cases were statistically significantly different from those among controls (χ(2)=8.66, P=0.003), with 402His/His or 402His/Try genotypes being over-represented among patients compared with controls (13.6% versus 9.4%, P<0.004). A multivariate regression analysis showed that a significantly increased risk of lung cancer for the 402His/His or 402His/Try carriers with OR (95% CI), 1.50 (1.12-2.00). When stratified by smoking status, the elevated risk of the cancer associated with variant CFH genotypes was observed among smokers, but not among non-smokers. When analyzed with cumulative smoking dose (pack-years), a super-multiplicative interaction was observed at different smoking levels. Among carriers with the 402Tyr/His or His/His genotype, the ORs of developing lung cancer for smoking<16, 16-28, or >28 pack-years were 0.98 (0.49-1.94), 2.36 (1.14-4.90), and 6.39 (3.49-11.68), respectively. These findings suggest that CFH Y402H polymorphism may interact with cigarette smoking to effect the development of lung cancer in the Chinese population.     

Stevioside ameliorates high-fat diet-induced insulin resistance and adipose tissue inflammation by downregulating the NF-κB pathway

Accumulating evidence suggests that adipose tissue is the main source of pro-inflammatory molecules that predispose individuals to insulin resistance. Stevioside (SVS) is a widely used sweetener with multiple beneficial effects for diabetic patients. In this study, we investigated the effect of SVS on insulin resistance and the pro-inflammatory state of adipose tissue in mice fed with a high-fat diet (HFD). Oral administration of SVS for 1month had no effect on body weight, but it significantly improved fasting glucose, basal insulin levels, glucose tolerance and whole body insulin sensitivity. Interestingly, these changes were accompanied with decreased expression levels of several inflammatory cytokines in adipose tissue, including TNF-α, IL6, IL10, IL1β, KC, MIP-1α, CD11b and CD14. Moreover, macrophage infiltration in adipose tissue was remarkably reduced by SVS. Finally, SVS significantly suppressed the nuclear factor-kappa b (NF-κB) signaling pathway in adipose tissue. Collectively, these results suggested that SVS may ameliorate insulin resistance in HFD-fed mice by attenuating adipose tissue inflammation and inhibiting the NF-κB pathway.     

Responses of phytoplankton diversity to physical disturbance under manual operation in a large reservoir, China

In aquatic ecosystems, physical disturbances have been suggested to be one of the main factors influencing phytoplankton structure and diversity. To elucidate whether large-scale artificial operation of a hydroelectric reservoir has potential impacts on phytoplankton diversity, the impact on phytoplankton biodiversity of physical disturbances under artificial operation from May 2007 to April 2008 in tributaries of the Three Gorges Reservoir (TGR), China, was analysed. Two disturbance parameters, i.e. the absolute incremental rates of discharge (R _d,i ) and precipitation (R _p,i ), were created in this study for evaluating physical disturbance intensities during low and high water level periods of the TGR. Results showed that river discharge seemed to be the main factor controlling the phytoplankton diversity in low water level periods (≤151 m), and that precipitation was a potential promoter of the physical disturbance. During the 156-m impoundment process, the species diversity clearly decreased due to the high dilution effect on the phytoplankton communities. At high water level periods (>151 m), the low levels of disturbance eventually allowed the phytoplankton community to approach competitive exclusion in late February 2008. Sharply declining diversity values appeared when the Dinophyta blooms occurred in late March and late April 2008 (Peridinium and Ceratium, respectively).     

Life cycle of <Emphasis Type="Italic">Haemaphysalis doenitzi</Emphasis> (Acari: Ixodidae) under laboratory conditions and its phylogeny based on mitochondrial 16S rDNA

The paper investigated the life cycle of the hard tick Haemaphysalis doenitzi under laboratory conditions and its phylogeny based on mitochondrial 16S rDNA. The results revealed that the complete life cycle of H. doenitzi requires a mean duration of 109.6 days ranging from 91 to 137 days and the average prefeeding, feeding and premoulting periods of larvae, nymphs and females and the eggs hatching period are 18.7, 26.9, 38.9, and 25.1 days, respectively. In addition, the weight of engorged females is highly correlated with the number of egg masses laid (r = 0.936, P < 0.001). The female reproductive efficiency index and reproductive fitness index are 13.4 and 12.8, respectively. The mean weight of the engorged nymphs (2.77 mg) moulting to females is much higher than those (1.68 mg) moulting to males, which could be used as an index to predict sexes in this species. The ratio of male to female is 1:1.01. Moreover, multisequence alignments and phylogenetic tree constructed based on the mitochondrial 16S rDNA sequences suggest that H. doenitzi is genetically close to H. longicornis.     

A New GA-Insensitive Semidwarf Mutant of Rice (Oryza sativa L.) with a Missense Mutation in the SDG Gene

A semidwarf line of Indica rice, Xinguiai, was derived from the progeny of a cross between the double dwarf mutant Xinguiaishuangai and the wild-type variety Nanjing 6. The semidwarf phenotype was controlled by the semidwarf gene, sdg. The second sheath and shoot elongation responses of the dwarf mutant to exogenous gibberellin (GA₃) showed that sdg was insensitive to gibberellin (GA), and its endogenous GAs content was higher than that in wild-type cultivars. The SDG gene was cloned by a map-based cloning method and sequencing analysis revealed that the coding region of sdg had a single nucleotide substitution resulting in a single amino acid change from alanine to threonine. A cleaved amplified polymorphic sequence marker was designed according to sequences from mutant and wild-type materials. This sequence marker could be used to distinguish wild types and mutants, and thus, could be used for molecular marker-assisted selection. The dwarf phenotype of the sdg mutant was restored to a normal phenotype by introducing the wild-type SDG gene. Rice transformation experiments and GUS staining demonstrated that the SDG gene was predominantly expressed in vegetative organs.     

Cloning and identification of a novel C18-Δ9 polyunsaturated fatty acid specific elongase gene from DHA-producing <Emphasis Type="Italic">Isochrysis galbana</Emphasis> H29

Isochrysis galbana, a marine prymnesiophyte microalga, is able to produce a high level of long chain polyunsaturated fatty acids such as docosahexaenoic acid (DHA, C22:6n-3). In this article, a novel gene (IgASE2) that encoded a C18-Δ9 polyunsaturase fatty acids specific (C18-Δ9-PUFAs-specific) elongase was isolated and characterized from DHA-rich microalga, I. galbana H29. A full-length cDNA of 1653 bp was cloned by rapidamplification of cDNA ends (RACE) PCR techniques. The IgASE2 contained a 786 bp ORF encoding a protein of 261 amino acids that shared 87% identity with the reported Δ9-elongase IgASE1, a 44 bp 5′ untranslated region and an 823 bp 3′ untranslated region. The function of IgASE2 was demonstrated by its heterologous expression in Saccharomyces cerevisiae. In S. cerevisiae, IgASE2 elongated linoleic acid (LA, C18:2n-6), α-linolenic (ALA, C18:3n-3) to eicosadienoic acid (EDA, C20:2n-6) and eicosatrienoic acid (ETrA, C20:3n-3). The conversion ratios of LA to EDA and ALA to ETrA were 60.47 and 58.36%, respectively. However, IgASE2 could not catalyze the elongation reactions of oleic acid (OA, C18:1n-9) and other fatty acids. These results confirmed that IgASE2 had C18-Δ9-PUFAs-specific elongase activity.     

VdNop12, containing two tandem RNA recognition motif domains,is a crucial factor for pathogenicity and cold adaption in Verticillium dahliae

Previous studies have reported the ability of fungi to overwinter in soil or on crop debris under different environmental conditions, but how fungi adapt to chilling is still largely unknown. In this study, we have identified and characterized the RNA binding protein (RBP) (VdNop12) by screening an Agrobacterium tumefaciens-mediated transformation-mediated insertional mutational library of Verticillium dahliae. We determined that this protein was essential to the pathogen for virulence on cotton plants. VdNop12 contains two tandem RNA recognition motif domains, and its orthologs are widely distributed in filamentous fungi. Mutants produced by disruption of VdNop12 showed defects in vegetative growth, conidiation and cell wall integrity. The mutant also showed an increase in sensitivity to low temperature, as compared to the wildtype and complementation strains. Yeast complementation assay showed that VdNop12 could functionally restore the growth phenotype of ΔScNop12 mutant of Saccharomyces cerevisiae at 15°C. We demonstrated that the VdNop12 is localized in the nucleus, and its loss resulted in the downregulated expression of several genes related to cAMP-PKA and MAPK pathways in V. dahliae. Our results demonstrated a crucial role of RBPs in the regulation of morphology, cold adaption, and pathogenic development in V. dahliae.