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Ethnic Han Chinese are at high risk of developing oesophageal squamous cell carcinoma ( ESCC). Aberrant activation of the AKT signalling pathway is involved in many cancers, including ESCC. Some single nucleotide polymorphisms ( SNPs) in genes involved in this pathway may contribute to ESCC susceptibility. We selected five potentially functional SNPs in AKT1 (rs2494750, rs2494752 and rs10138277) and AKT2 (rs7254617 and rs2304186) genes and investigated their associations with ESCC risk in 1117 ESCC cases and 1096 controls in an Eastern Chinese population. None of individual SNPs exhibited an association with ESCC risk. However, the combined analysis of three AKT1 SNPs suggested that individuals carrying one of AKT1 variant genotypes had a decreased ESCC risk [adjusted odds ratio ( OR) = 0.60, 95% CI = 0.42-0.87]. Further stratified analysis found that AKT1 rs2294750 SNP was associated with significantly decreased ESCC risk among women (adjusted OR = 0.63, 95% CI = 0.43-0.94) and non-drinkers ( OR = 0.79, 95% CI = 0.64-0.99). Similar protective effects on women (adjusted OR = 0.56, 95% CI = 0.37-0.83) and non-drinker (adjusted OR = 0.75, 95% CI = 0.60-0.94) were also observed for the combined genotypes of AKT1 SNPs. Consistently, logistic regression analysis indicated significant gene-gene interactions among three AKT1 SNPs ( P < 0.015). A three- AKT1 SNP haplotype (C-A-C) showed a significant association with a decreased ESCC risk (adjusted OR = 0.70, 95% CI = 0.52-0.94). Multifactor dimensionality reduction analysis confirmed a high-order gene-environment interaction in ESCC risk. Overall, we found that three AKT1 SNPs might confer protection against ESCC risk; nevertheless, these effects may be dependent on other risk factors. Our results provided evidence of important gene-environment interplay in ESCC carcinogenesis. [ABSTRACT FROM AUTHOR]

Sugar plays an essential role in plant cold acclimation (CA), but the interaction between CA and sugar remains unclear in tea plants. In this study, during the whole winter season, we investigated the variations of sugar contents and the expression of a large number of sugar-related genes in tea leaves. Results indicated that cold tolerance of tea plant was improved with the development of CA during early winter season. At this stage, starch was dramatically degraded, whereas the content of total sugars and several specific sugars including sucrose, glucose and fructose were constantly elevated. Beyond the CA stage, the content of starch was maintained at a low level during winter hardiness (WH) period and then was elevated during de-acclimation (DC) period. Conversely, the content of sugar reached a peak at WH stage followed by a decrease during DC stage. Moreover, gene expression results showed that, during CA period, sugar metabolism-related genes exhibited different expression pattern, in which beta-amylase gene ( CsBAM), invertase gene ( CsINV5) and raffinose synthase gene ( CsRS2) engaged in starch, sucrose and raffinose metabolism respectively were solidly up-regulated; the expressions of sugar transporters were stimulated in general except the down-regulations of CsSWEET2, 3, 16, CsERD6.7 and CsINT2; interestingly, the sugar-signaling related CsHXK3 and CsHXK2 had opposite expression patterns at the early stage of CA. These provided comprehensive insight into the effects of CA on carbohydrates indicating that sugar accumulation contributes to tea plant cold tolerance during winter season, and a simply model of sugar regulation in response to cold stimuli is proposed. [ABSTRACT FROM AUTHOR]

The bioactivities of methyl eugenol (ME) against rice insect pests, the brown planthopper (BPH), Nilarparvata lugens , the leaf folder (RLF), Cnaphalocrocis medinalis , the striped stem borer (SSB), Chilo suppressalis , and their major natural enemies, a predator C yrtorhinus lividipennis and parasitoids Anagrus nilaparvatae and Trichogramma japonicum were determined under laboratory conditions. The results showed ME had repellent, systemic and contact insecticidal activities against BPH. The nymphal mortality increased with raised ME concentrations. The LC 50 value for BPH using an impregnated filter paper bioassay was 1025 mg/L which was much lower than that of 3778 mg/L obtained from an immersion bioassay. ME also had a contact toxicity against RLF larvae with a LC 50 of 250 mg/L. However, bioactivity of ME against SSB larvae was much lower than against RLF. Only 21.8% of 2nd instar SSB larvae died at 24 h after being treated with 8000 mg/L ME. In addition, ME also had contact toxicity to predator C. lividipennis and parasitic natural enemies A. nilaparvatae , T. japonicum , with LC 50 values of 527, 105 and 123 mg/L, respectively. Even so, the toxicity of ME to natural enemies was much lower than that of chemical insecticides. [ABSTRACT FROM AUTHOR]

The specific primers of five species of endosymbiotic bacteria were designed to determine their numbers in three virulent populations of brown planthopper, Nilapavata lugens Stål, and to assess changes during adaptation to different resistant varieties using fluorescent quantitative PCR. The results showed that Chryseobacterium was the dominant bacteria in all three populations of brown planthopper, followed by Acinetobacter in TN1 population, Arsenophonus and Serratia in Mudgo population, and Arthrobacter and Acinetobacter in ASD7 population. When the TN1 population of brown planthopper was transferred to ASD7 (with resistant gene bph2) rice plants, Chryseobacterium was still the dominant bacteria, but the originally subdominant Acinetobacter declined to a level that was not significantly different from that of other endosymbiotic bacteria. After they were transferred to Mudgo (with resistant gene Bph1), Serratia and Arsenophonus increased significantly and became the dominant bacteria. However, they declined to a level that was not significantly different from that of the three other species after two generations. When ASD7 and Mudgo populations of brown planthopper were transferred to the susceptible variety TN1, the community of endosymbiotic bacteria in the ASD7 population of brown planthopper showed no significant changes. However, the numbers of Acinetobacter and Arthrobacter in the Mudgo population of brown planthopper exhibited a transient increase and returned to their original levels after two generations. After the Mudgo population of brown planthopper was transferred to ASD7 rice plants, the quantity of endosymbiotic bacteria fluctuated, but the bacterial structure did not change significantly. However, after the ASD7 population of brown planthopper was transferred to the Mudgo rice plants, the bacterial structure changed significantly. Serratia and Arsenophonus increased significantly and became dominant. Although Serratia and Arsenophonus decreased significantly after a generation, they were still greater than Chryseobacterium. It was presumed that Chryseobacterium was dominant in all three populations of virulent brown planthoppers, but had no significant effect on virulence variation of brown planthopper. However, Serratia and Arsenophonus might be correlated with virulence variation of brown planthopper. [ABSTRACT FROM AUTHOR]

In this study, the brown planthopper (BPH), Nilaparvata lugens (Hemiptera: Delphacidae), cultured on Bt rice lines (T1C-19 with cry1C gene and T2A-1 with cry2A gene) and their parental rice MH63, were treated with a series of concentrations of triazophos and deltamethrin when they developed up to the third instar for the evaluation of the effects of Bt rice on BPH resurgence induced by pesticides. The results indicated that BPH nymphal duration decreased with the increasing concentration of deltamethrin, while no significant differences of BPH nymphal duration were observed on the same rice variety treated with the different concentrations of triazophos. Furthermore, the survival rate of BPH significantly declined and their fecundity significantly increased with the increasing concentration of insecticides. However, ecological fitness parameters of BPH including nymphal duration, survival rate, female adult mass, fecundity and egg hatchability were not significantly different among Bt and non Bt rice varieties when they treated with the same concentration of insecticide. These results implied that no significant difference in the BPH resurgence induced by pesticides was observed among the two tested Bt rice varieties and their non-Bt parental rice variety. [ABSTRACT FROM AUTHOR]

Rice black streak dwarf virus (RBSDV) is transmitted by the small brown planthopper (SBPH), Laodelphax striatellus (Fallen). Non-vector rice brown planthopper (BPH), Nilaparvata lugens (Stål), shares the same host rice plants with SBPH in paddy fields. The changes in nutritional composition of rice plants infected by RBSDV and the ecological fitness of BPH feeding on the infected plants were studied under both artificial climate chamber and field conditions. Contents of 16 detected amino acids and soluble sugar in RBSDV infected rice plants were higher than those in the healthy ones. On the diseased plants BPH had significantly higher nymphal survival rates, nymphal duration of the males, weight of the female adults, as well as egg hatchability compared to BPH being fed on healthy plants. However, there was no obvious difference in female nymph duration, longevity and fecundity. Defense enzymes (superoxidase dismutase, SOD and catalase, CAT) and detoxifying enzymes (carboxylesterase, CAE and glutathione S-transferase, GST) in BPH adults fed on diseased plants had markedly higher activities. The results indicate rice plants infected by RBSDV improved the ecological fitness of the brown planthopper, a serious pest but not a transmitter of the RBSDV virus. [ABSTRACT FROM AUTHOR]

The ultrasonic longitudinal wave reflection technology and the laser thickness measurement technology are used to monitor the curing process of solid rocket engine liner. An ultrasonic system is designed to monitor the curing process of liner in real-time to meet the need of using common ultrasonic probe under the curing temperature. The curing state of liner is characterized by the changes of liner thickness,ultrasonic longitudinal wave velocity and acoustic attenuation coefficient. The experimental results show that the liner thickness and acoustic attenuation coefficient decrease and the propagation velocity of longitudinal wave increases gradually during the curing reaction of liner,which reflects the change in curing state of liner,and its "half curing"state can be determined. [ABSTRACT FROM AUTHOR]

Plant viruses transmitted by arthropods, as an important biotic factor, may not only directly affect the yield and quality of host plants, and development, physiological characteristics and ecological performances of their vector arthropods, but also directly or indirectly affect the non-vector herbivorous arthropods and their natural enemies in the same ecosystem, thereby causing influences to the whole agro-ecosystem. This paper reviewed the progress on the effects of plant viruses on herbivorous arthropods, including vector and non-vector, and their natural enemies, and on their ecological mechanisms to provide a reference for optimizing the management of vector and non-vector arthropod populations and sustainable control of plant viruses in agro-ecosystem. [ABSTRACT FROM AUTHOR]

Abstract: A population of rice brown planthopper (BPH) Nilaparvata lugens collected from a paddy field in Hangzhou was successively reared on susceptible rice Taichung Native 1 (TN1) in a laboratory free from insecticides for more than 14 generations. The changes in susceptibility to insecticides and ecological fitness on different resistant rice varieties were monitored in each generation. The resistance ratio to imidacloprid sharply declined with the succession of rearing generations without insecticides from 359.94-fold at F1 to 6.50-fold at F14 compared with the susceptible strain, and the resistance ratio to chlorpyrifos was from 9.90-fold at F1 to 5.94-fold at F14. Nymphal duration and weights of newly hatched female adults were significantly affected by rice variety, generation and their interactions, but nymphal survival was significantly affected by the generation only. The ratio of brachypterous adults in males was affected by the generation and generation × variety interaction, whereas no difference was found in females. Nymphal duration extended with increasing generations, and the female nymphal duration was shorter in the susceptible variety TN1 than those in the resistant varieties IR26 and IR36. In addition, the female adult weight in TN1 was higher than those in IR26 and IR36. These results indicated that the resistance of field BPH population to insecticides was reversed after several generations of no-exposure to insecticides, and the ecological fitness in TN1 was higher than those in IR26 and IR36. These findings suggested the rational and reduced use of insecticides in combination with the manipulation of resistant rice varieties would be effective for BPH management. [Copyright &y& Elsevier]

Reduction of noncrop habitats, intensive use of pesticides and high levels of disturbance associated with intensive crop production simplify the farming landscape and bring about a sharp decline of biodiversity. This, in turn, weakens the biological control ecosystem service provided by arthropod natural enemies. Strategic use of flowering plants to enhance plant biodiversity in a well-targeted manner can provide natural enemies with food sources and shelter to improve biological control and reduce dependence on chemical pesticides. This article reviews the nutritional value of various types of plant-derived food for natural enemies, possible adverse effects on pest management, and the practical application of flowering plants in orchards, vegetables and field crops, agricultural systems where most research has taken place. Prospects for more effective use of flowering plants to maximize biological control of insect pests in agroecosystem are good but depend up on selection of optimal plant species based on information on the ecological mechanisms by which natural enemies are selectively favored over pest species. [ABSTRACT FROM AUTHOR]

Abstract: The structures of bacterial communities in the brown planthopper (BPH) Nilaparvata lugens (Stål) from different geographic and resistant virulent populations were analyzed by using denatured gradient gel electrophoresis (DGGE). Results showed that the bacterial communities in BPH nymph from the first to the fifth instars varied with nymphal growth and development. The bacterial communities in the first-instar BPH nymph were similar to those in adults. Nine geographic BPH populations were divided into three groups based on the cluster analysis of DGGE fingerprint. The first group was from the Philippines; the second group was from Thailand and Hainan, Yunnan and Zhejiang provinces of China; and the third group was from Vietnam and Guangxi, Hunan and Jiangxi provinces of China. BPH populations adapted to different resistant rice varieties. The BPH populations from Mudgo (with resistant gene Bph1) and ASD7 (with resistant gene bph2) differed with those of the susceptible rice variety TN1. [Copyright &y& Elsevier]

Background: Caspase 7 (CASP7) is an important regulator and executioner in the apoptosis pathway and plays a crucial role in cancer development and progression. However, few studies have evaluated associations between functional single nucleotide polymorphisms (SNPs) in the 3′ untranslational region (UTR) of CASP7 and risk of gastric cancer. Methods: In a case-control study of 1117 patients with gastric cancer and 1146 cancer-free controls with frequency matching on age and sex, we genotyped four potentially functional SNPs (rs4353229T>C, rs10787498T>G, rs1127687G>A and rs12247479G>A) located in the microRNA binding sites of the CASP7 3′ UTR by using Taqman assays and evaluated their associations with risk of gastric cancer by using logistic regression analyses as well as multifactorial dimension reduction (MDR) analysis. Results: In the single-locus analysis, only the CASP7 rs4353229 TT genotype was associated with 0.83-fold decreased risk (95% confidence interval [CI] = 0.70–0.98) of gastric cancer under a recessive model, compared with the CT/CC genotypes. In the combined analysis of all four SNPs, we found that the risk of gastric cancer decreased by 19% in those carrying any of the risk genotypes (adjusted odds ratio = 0.81, 95% CI = 0.68–0.96), compared with those carrying zero risk genotypes, and this risk was more evident in subgroups of younger age (<59 years), females, non-smokers, non-drinkers and patients with non-gastric cardia adenocarcinoma. Further MDR analysis suggested some evidence of interactions between the combined genotypes and other risk factors for gastric cancer. Conclusions: Potentially functional CASP7 variants may contribute to risk of gastric cancer. Larger studies with different ethnic populations are warranted to validate our findings. [ABSTRACT FROM AUTHOR]