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双胸复合体(BX-C)作为Hox基因簇的两个复合体之一,包括Ultrabithorax(Ubx)、abdominal-A(abd-A)、Abdominal-B(Abd-B)3个基因及其间的顺式调控区域,在动物躯体模式的发育过程中具有重要作用。昆虫双胸复合体基因主要规定其后胸及腹部形态的特异性,通过与其上、下游靶基因一起或以自身基因间的相互调控作用行使功能。本文以模式昆虫果蝇为主,结合家蚕、蝴蝶、赤拟谷盗等,对双胸复合体在昆虫体节规定、附件发育及内部器官分化等过程中的作用与基因间的相互调控关系进行了综述。 相似文献
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Beynon SA 《Veterinary parasitology》2012,189(1):125-135
Sheep ectoparasiticides, which include the synthetic pyrethroids, the organophosphates, the 'insect'-growth regulators, the formamidines and the spinocyns, enter into the environment primarily through disposal of dip or fleece scours, as well as with contaminated faeces and urine. Due to the large quantities of spent dip, risks associated with environmental contamination are high. Synthetic pyrethroids and organophosphates pose risks to dung, soil and aquatic fauna; concerns over potential ecotoxicity to vertebrates and invertebrates have resulted in the cessation of their use in many countries. There is very little information regarding the ecotoxicity of 'insect'-growth regulators, formamidines or spinocyns, with no studies focussing on sheep. Here, the impact of sheep ectoparasiticides is discussed in terms of their potential to enter into the environment, their toxicity and their impact on ecosystem functioning. Where there are no data for excretion or toxicity of the ectoparasiticides used in sheep production, examples to demonstrate potential impacts are taken from laboratory ecotoxicity tests and the cattle literature, as well on work with foliar insecticides. Future research priorities are suggested to allow assessment of the environmental consequences of sheep ectoparasiticide treatments, which are essential for future sustainable sheep production. 相似文献
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《Plant Production Science》2013,16(3):157-164
AbstractSince the establishment of the International Rice Research Institute (IRRI) in 1960, IRRI’s breeding effort in varietal improvement for irrigated lowland has passed four decades. Breeding of semi-dwarf rice varieties such as IR8 at IRRI during first decade from 1960 to 1969 resulted in quantum leaps in yield potential, which marked the green revolution in Asia. During the second decade from 1970 to 1979, the primary emphasis of rice improvement has been directed towards incorporation of multiple disease and insect resistance and shortening of growth duration. Grain quality was the main target of crop improvement at IRRI during the third decade from 1980 to 1989. The fourth decade from 1990 to 1999 and beyond was focused again on the improvement of yield potential by developing hybrid rice and new plant type. Up to 1999, 46 indica inbred varieties and 2 indica/indica hybrid rice varieties were developed by IRRI and released in the Philippines for the irrigated lowland rice systems. Large-scale adoption of these improved varieties under modern crop management practices has resulted in a dramatic increase in rice production in major rice-growing countries. The hybrid varieties between indicas increased yield potential by 9% under the tropical conditions. New plant type (NPT) breeding has not yet resulted in an increase in yield potential. The second generation NPT developed by crossing tropical japonica with indica has demonstrated some promising results in terms of improvements in yield potential, disease and insect resistance, and grain quality. 相似文献
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豆谷类及其制品辐照杀虫防霉剂量要求研究 总被引:1,自引:0,他引:1
[目的]研究豆谷类及其制品辐照杀虫防霉工艺,阐述吸收剂量确定的依据。[方法]根据国内外研究结果和国际上有关辐照豆谷类及其制品杀虫防霉工艺规范中的规定,采用60Co-γ射线对豆谷类及其制品进行辐照杀虫防霉处理。[结果]试验得出,确定豆类、谷类辐照杀虫最低有效剂量为0.3kGy,豆类、谷类及其制品类辐照防霉最低有效剂量为3.0kGy,最高耐受剂量为7.0kGy。确定豆谷类及其制品辐照杀菌的适宜剂量范围为3.0~5.0kGy。[结论]研究可为提高优质谷类及其制品卫生质量品质、规范辐照加工生产提供参考依据。 相似文献
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Investigations were conducted to understand the direct effects of rising temperature and the host-mediated effects of elevated CO2 (eCO2) on Spodoptera litura (Fabricius) (Noctuidae: Lepidoptera). This study involved i. the construction of life tables of S. litura at six constant temperatures viz., 20, 25, 27, 30, 33 and 35°C ± 0.5 °C reared on peanut (Arachis hypogaea L.) grown under eCO2 (550 ppm) concentration in open top chambers ii. Estimation of threshold temperatures and thermal constants and iii. Prediction of the pest scenarios during near and distant future climate change periods. Significantly lower leaf nitrogen, higher carbon and a higher relative proportion of carbon to nitrogen (C:N) were observed in peanut foliage grown under eCO2 over ambient CO2 (aCO2). The mean development time (days) of each stage, egg, larva, pupa, pre-oviposition and total life span decreased from 20 to 35 °C temperature on eCO2 foliage. The thermal requirement of S. litura from egg to egg (within the range of 20 °C–35 °C) was 538.5 DD on eCO2 as against 494.5 DD on aCO2 foliage. Finite (λ) and intrinsic rates of increase (rm), net reproductive rate (Ro), mean generation time (T) and doubling time (DT) of S. litura varied significantly with temperature and CO2 and were found to have quadratic relationships with temperature. The present results on life table parameters estimated by the bootstrap technique showed that the ‘rm’ values of S. litura on eCO2 foliage were higher than those in the literature indicating a significant influence of eCO2. The reduction of ‘T’ was noticed from a maximum of 50 days at 20 °C to minimum of 22 days at 35 °C and ‘λ’ which is the indicator of reproductive value of new eggs was highest at 35 °C and showed a negative relationship with temperature. The data on these life table parameters were plotted against temperature and two non-linear models developed for both CO2 conditions and used for predicting the pest scenarios. Prediction of pest scenarios based on PRECIS A1B emission scenario data at eleven peanut growing locations of the country during near future (NF) and distant future (DF) climate change periods showed an increase of ‘rm’ and ‘λ’ with varied ‘Ro’ and reduced ‘T’. The present results indicate that temperature and CO2 are vital in influencing the growth and life table parameters of S. litura and that pest incidence is likely to be higher in the future. 相似文献