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Genes normally resident in euchromatic domains are silenced when packaged into heterochromatin, as exemplified in Drosophila melanogaster by position effect variegation (PEV). Loss-of-function mutations resulting in suppression of PEV have identified critical components of heterochromatin, including proteins HP1, HP2, and histone H3 lysine 9 methyltransferase. Here, we demonstrate that this silencing is dependent on the RNA interference machinery, using tandem mini-white arrays and white transgenes in heterochromatin to show loss of silencing as a result of mutations in piwi, aubergine, or spindle-E (homeless), which encode RNAi components. These mutations result in reduction of H3 Lys9 methylation and delocalization of HP1 and HP2, most dramatically in spindle-E mutants.  相似文献   
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Sericulture is an agro-based industry, which heavily depends on mulberry (Morus spp.) for its sustainability, as mulberry leaf is the only available feed for the silkworm Bombyx mori L. Sericulture, in West Bengal and other subtropical regions in India, suffers from lack of adequate quantity of quality mulberry leaf during the colder months, the best season for rearing the high yielding bivoltine silkworm hybrids. In order to develop mulberry varieties, which can sustain normal growth during these colder months to yield better, efforts have been made in different research institutes in India. The present report is part of such an effort in which accessions in germplasm bank were screened for better growth, leaf retention and leaf yield contributing associated traits. Twenty three selected parents were crossed, 3,500 seeds were sown, 2,700 seedlings were transplanted to progeny row trail, selected 210 hybrids were evaluated under primary yield trial and finally nine hybrids along with a control variety were studied in detail for all leaf yield contributing traits under final yield trial. Stability analysis was adopted to identify hybrids, which can yield stably across seasons. The hybrids CT-44 and CT-11 out yielding the control by 17.17 and 7.11% were selected as these hybrids yield 7.93 and 8.15 mt/ha leaf respectively during the colder months (February) for their direct use as cultivars in West Bengal and other subtropical areas of India to sustain bivoltine sericulture to produce quality and gradable silk fibers.  相似文献   
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The present study was on assessment of the anti-parasitic activities of nickel nanoparticles (Ni NPs) against the larvae of cattle ticks Rhipicephalus (Boophilus) microplus and Hyalomma anatolicum (a.) anatolicum (Acari: Ixodidae), fourth instar larvae of Anopheles subpictus, Culex quinquefasciatus and Culex gelidus (Diptera: Culicidae). The metallic Ni NPs were synthesized by polyol process from Ni-hydrazine as precursor and Tween 80 as both the medium and the stabilizing reagent. The synthesized Ni NPs were characterized by Fourier transform infrared (FTIR) spectroscopy analysis which indicated the presence of Ni NPs. Synthesized Ni NPs showed the X-ray diffraction (XRD) peaks at 42.76°, 53.40°, and 76.44°, identified as 1 1 1, 2 2 0, and 2 0 0 reflections, respectively. Scanning electron microscopy (SEM) analysis of the synthesized Ni NPs clearly showed that the Ni NPs were spherical in shape with an average size of 150 nm. The Ni NPs showed maximum activity against the larvae of R. (B.) microplus, H. a. anatolicum, A. subpictus, C. quinquefasciatus and C. gelidus with LC50 values of 10.17, 10.81, 4.93, 5.56 and 4.94 mg/L; r2 values of 0.990, 0.993, 0.992, 0.950 and 0.988 and the efficacy of Ni-hydrazine complexes showed the LC50 values of 20.35, 22.72, 8.29, 9.69 and 7.83 mg/L; r2 values of 0.988, 0.986, 0.989, 0.944 and 0.978, respectively. The findings revealed that synthesized Ni NPs possess excellent larvicidal parasitic activity. To the best of our knowledge, this is the first report on larvicidal activity of blood feeding parasites using synthesized Ni NPs.  相似文献   
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The present study was aimed to investigate the combined effects of green tea and vitamin E on heart weight, body weight, serum marker enzymes, lipid peroxidation, endogenous antioxidants and membrane bound ATPases in isoproterenol (ISO)-induced myocardial infarction in rats. Adult male albino rats, treated with ISO (200 mg/kg, s.c.) for 2 days at an interval of 24 h caused a significant (P < 0.05) elevation of heart weight, serum marker enzymes, lipid peroxidation and Ca+2 ATPase level whereas there was a significant (P < 0.05) decrease in body weight, endogenous antioxidants, Na+/ K+ ATPase and Mg+2 ATPase levels. Administration of green tea (100 mg/kg/day, p.o.) and vitamin E (100 mg/kg/day, p.o.) together for 30 consecutive days and challenged with ISO on the day 29th and 30th, showed a significant (P < 0.05) decrease in heart weight, serum marker enzymes, lipid peroxidation, Ca+2 ATPase and a significant increase in the body weight, endogenous antioxidants, Na+/K+ ATPase and Mg+2 ATPase when compared with ISO treated group and green tea or vitamin E alone treated groups. These findings indicate the synergistic protective effect of green tea and vitamin E during ISO induced myocardial infarction in rats.  相似文献   
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Insecticidal seed treatment is an alternative method to spray and granular applications. It can protect the crop right from germination to reproductive stage. Recurrent use of chemical insecticides destabilizes the ecosystem and enhances the development of resistance in pest population. Use of biopesticides like neem oil (NO) is a promising one in this situation. Two field experiments were conducted to test the efficacy of NO as a seed dresser (20 ml kg−1) and the effect was compared with systemic chemical insecticides imidacloprid (7 g kg−1) and carbosulfan (7 g kg−1) and Pseudomonas fluorescens (10 g kg−1). Field studies revealed that the neem oil 60EC (C) (NO 60EC (C)) recorded minimum population of sucking pests Leafhopper—Amrasca biguttula biguttula Ishida and Aphids—Aphis gossypii Glover (Homoptera: Cicadellidae and Aphididae), i.e., below the ETL (2 number per leaf) up to 45 days after sowing and provided better yield compared to control. Although the systemic chemical insecticide imidacloprid performed better by recording 11,280 and 11,580 kg ha−1 of marketable fruit yield, NO 60EC (C) also recorded about twofold increase in marketable fruit yield 11,000 and 10,620 kg ha−1, respectively, in 2001 and 2002 experiments. Results of this study suggest that NO could be used as a potential seed dresser for managing sucking pests in okra.  相似文献   
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Tropical Animal Health and Production - Brucellosis is an important zoonosis worldwide. In livestock, it frequently causes chronic disease with reproductive failures that contribute to production...  相似文献   
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