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从害虫马尾松毛虫中提取甲壳素的初步研究 总被引：6，自引：1，他引：6
采用酸碱法对马尾松毛虫蛹中甲壳素的提取方法进行了初步研究。重点分析了N aOH不同处理条件对脱有机物质和甲壳素产率的影响,确定了从马尾松毛虫蛹中提取甲壳素的基本工艺:(1)脱矿物质:盐酸浓度为2.5%,浸泡时间为20 h,浸泡温度为30℃;(2)脱有机物质:N aOH浓度为6%,浸泡温度为75℃,浸泡时间为10 h;(3)脱色:双氧水浓度为9%,浸泡时间为2.5 h,浸泡温度为80℃。在此条件下,获得的甲壳素产品为白色粉状固体,其N含量为6.87%,灰分为1.19%,水分为8.37%。产率为29.97%。产品的N含量达到食品级甲壳素标准,灰分含量达到工业级甲壳素标准。实验有助于后续深入研究马尾松毛虫蛹中甲壳素的提取,也为今后进一步制备虫蛹壳聚糖打下了基础。 相似文献
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Pal-Bhadra M Leibovitch BA Gandhi SG Rao M Bhadra U Birchler JA Elgin SC 《Science (New York, N.Y.)》2004,303(5658):669-672
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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New icetexane diterpenes (1-2); 8, 11, 13-icetexatriene-10-hydroxy, 11, 12, 16-tri acetoxyl (1) and 8, 11, 13-icetexatriene-7, 10, 11-dihydroxy-12, 13-dihydrofuran (2) along with six known compounds namely acetoxy syranzaldehyde (3), syranzaldehyde (4), coniferaldehyde (5), lupeol (6), betulin (7), and 4-(4-methoxy phenyl)-2-butanone (8) were isolated from the roots of Premna tomentosa. The structures of compounds 1 and 2 were established by detailed spectral analysis using UV, IR, 1H NMR, 13C NMR, 1D, 2D and Mass. The newly isolated compounds were screened for rat intestinal α-glucosidase inhibitory and free radical (DPPH) scavenging potentiality. The new icetexane diterpenes (1, 2) and compound 3 were found to have significant α-glucosidase inhibitory and also free radical scavenging (DPPH) activities. 相似文献
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M del C Díaz NV González S Gómez MA Quiroga R Najle CG Barbeito 《Reproduction in domestic animals》2014,49(6):1049-1056
Cadmium (Cd) is a well‐known toxicant targeting many organs, among them placenta. This heavy metal also has embryonary and foetal toxicity. This study was undertaken to analyse the effect of a single Cd dose administered at 4, 7, 10 or 15 days of gestation on the offspring of pregnant rats sacrificed at 20 days of gestation. Cadmium chloride was administered subcutaneously at 10 mg/kg body weight to Wistar pregnant dams; control animals received a proportionate volume of sterile normal saline by the same route. Maternal uteri, livers, kidneys and lungs, and foetuses were examined at necropsy. Samples of maternal organs and whole foetuses were collected for histopathologic examination, determination of Cd levels and staining by the Alizarin red S technique. Results revealed a clear embryotoxic and a teratogenic effect of this heavy metal, the former as a significant increase in the number of resorptions, and the latter as significant decrease of the gestational sac weight, and the size and weight of foetuses of Cd‐treated dams as well as induced malformations in skull bones, vertebrae and thoracic, and pelvian limbs. The deleterious effects found were similar to those previously reported for other animal models suggesting a high conservation of the pathogenic mechanisms of Cd. Additionally, many of the addressed aspects showed a slight dependence on the time of administration of the toxic that might be due to the accumulation of the metal in different organs, as we were able to demonstrate by the analysis of its concentration. 相似文献
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Essential oil incorporated alginate coating provides a novel way to improve the safety and shelf life of pangasius (Pangasianodon hypophthalmus) fillet. Oils from the leaves and buds of clove, flowering tops of rosemary, and dried seeds of thyme were incorporated separately in alginate coating. All the plant oils showed antibacterial activity, but the zone of inhibition was relatively larger for thyme oil. Alginate coating was performed using sodium alginate (1.5%), glycerol (10%), and calcium chloride (2%) and plant oil at 1% (v/v). The coated fillets were stored under chilled conditions and samples were analyzed for bacteriological, chemical, sensory, color, and texture parameters. Psychrotrophic counts crossed 7 log cfu/g by the 13th day and 15th day of chilled storage in control and plant oil treated fillets, respectively. The peroxide value of treated fillets was relatively low. Texture profile analysis indicated that plant oil incorporated alginate coating reduced the rate of loss of texture (softening) during chilled storage. Plant essential oil incorporated alginate gels were relatively better compared to control fillets in preserving pangasius fillet quality during chilled storage, and incorporation of thyme oil was relatively better compared to clove leaf oil, clove bud oil, and rosemary oils. 相似文献
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Hymavathi A Devanand P Suresh Babu K Sreelatha T Pathipati UR Madhusudana Rao J 《Journal of agricultural and food chemistry》2011,59(5):1653-1657
The vapor-phase toxicity of Derris scandens Benth.-derived constituents was evaluated against four stored-product pests ( Callosobruchus chinensis L., Sitophilus oryzae L., Rhyzopertha dominica L., and Tribolium castaneum H.) using fumigation bioassays and compared to those of commonly used insecticides. The structures of all constituents of were characterized by spectroscopic analyses [nuclear magnetic resonance (NMR) and mass spectrometry]. The sensitivity of the test insect to compounds varied with exposure time, concentration, and insect species. Over 100% mortality after 24 h was achieved with the compounds osajin (2), scandinone (5), sphaerobioside (8), and genistein (9) against all of the test insects, while laxifolin (3) and lupalbigenin (4) showed 100% mortality after 72 h against T. csataneum and R. dominica . Scandenone (1), scandenin A (6), and scandenin (7) were less effective. Among the insects, C. chinensis , S. oryzae , and R. dominica were more susceptible to the treatments, whereas T. castaneum was less susceptible. The results of fumigation tests indicated that compounds from D. scandens whole plant extract are potential candidates to control stored-product pests. 相似文献
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Following an identified use of the plant as analgesic in traditional medicine, the hexane, chloroform and ethyl acetate extracts of Euphorbia heterophylla root have been tested for antinociceptive activity in rats. All extracts showed significant effects at doses of 150-300 mg/kg i.p. 相似文献
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We report the discovery of an orientational transition of bent-core molecules in a background anisotropic medium, in this case a smectic liquid crystal made of rod-like molecules. The resulting director is apolar in nature, and the medium can be described as an orthogonal biaxial smectic. The detailed phase diagram of mixtures of the two types of compounds revealed the induction of two liquid crystalline phases that are specific to compounds with bent-core molecules. The chemical nature of the bounding surface had a marked influence on the observed textures. 相似文献
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