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101.
在大田试验条件下, 以鲁棉研28为试验材料, 研究不施钾肥(CK)、一次性基施硫酸钾(T1)、分次(1/2基施, 1/2于花铃期追施)施用硫酸钾(T2)、一次性基施控释复合肥(T3) 4个处理的棉花叶片保护酶活性、产量及钾肥利用效率变化。结果表明, 与不施钾处理相比, 施钾可显著增加叶片叶绿素、可溶性蛋白含量, 降低MDA含量, 提高SOD、CAT活性(叶龄30、45、60 d), 降低POD活性(叶龄30、45 d), 提高籽棉产量和皮棉产量;与一次性基施硫酸钾和控释复合肥相比, 分次(1/2基施、1/2花铃期追施)施用硫酸钾可显著提高叶片可溶性蛋白含量(叶龄30、45、60 d)和SOD (叶龄15、30、45 d)、CAT(叶龄15、30 d)活性, 降低MDA含量(叶龄30、45、60 d)和POD活性(叶龄30 d), 提高籽棉产量、皮棉产量和钾肥生产效率。本试验条件下, 分次(1/2基施、1/2花铃期追施)施用硫酸钾是兼顾高产高效的施肥方式。  相似文献   
102.
Identification of a juvenile hormone-like compound in a crustacean   总被引:3,自引:0,他引:3  
Juvenile hormone (JH) has central roles in the regulation of insect development and reproduction but has not previously been identified in other arthropod classes. The hemolymph of a crustacean, Libinia emarginata (Leach), has now been analyzed for JH-like compounds. Samples contained 0.003 to 0.030 nanogram of JH III per milliliter and 10 to 50 nanograms of methyl farnesoate per milliliter; methyl farnesoate is a compound structurally related to JH III that has JH bioactivity. Several tissues were examined for synthesis and secretion of JH-like compounds. Of these tissues, only the mandibular organs produced and secreted JH III and methyl farnesoate. However, microchemical analysis revealed that this JH III was racemic, and thus likely an artifactual oxidation product of methyl farnesoate. Secretion of methyl farnesoate was related to reproduction in females, with the highest rates observed in Libinia near the end of the ovarian cycle when oocyte growth and vitellogenesis are greatest. These results indicate that JH-like compounds such as methyl farnesoate have regulatory roles in crustaceans.  相似文献   
103.
不同灌溉处理对小麦蛋白组分和面团流变学特性的影响   总被引:3,自引:0,他引:3  
为阐明不同灌溉处理对强筋和弱筋小麦品质的影响,以藁城8901(强筋)和山农1391(弱筋)品种为材料,设3个灌溉处理,于花后7~35 d分别测定其籽粒蛋白质及其组分含量、以及粉质仪和拉伸仪参数。结果表明,对于籽粒清蛋白和球蛋白,随灌溉量的增加,藁城8901和山农1391的含量均提高;适量灌溉(浇起身水和孕穗水各75 mm)能提高强筋品种籽粒醇溶蛋白和谷蛋白含量,降低弱筋品种的含量。藁城8901籽粒谷蛋白、GMP含量、HMW-GS含量、面粉沉淀值、粉质仪参数和拉伸仪参数显著高于山农1391。灌溉能显著提高藁城8901面粉沉淀值、粉质仪参数和拉伸仪参数,山农1391面团流变学特性对灌溉的反应较迟钝,这与不同灌溉处理对不同品种籽粒醇溶蛋白、谷蛋白、GMP和HMW-GS含量的影响密切相关。  相似文献   
104.
This study investigated gender, caponization and exogenous estrogen effects on lipids, bone and blood characteristics in Taiwan country chickens. Thirty male chickens were caponized at 8 weeks (capons); 15 capons were injected with estrogen (5 mg/bird estradiol 3‐benzoate) every 2 weeks from 8 to 28 weeks, and 15 sham‐operated male (shams) chickens and 15 females were selected for this trial. The results showed that the shams had lower relative abdominal and chest subcutaneous fat than females (P < 0.05). The estrogen‐treated capons had greater relative abdominal and chest subcutaneous fat than shams and capons (P < 0.05), which might result from higher blood very low‐density lipoproteins and triacylglycerol concentrations (P < 0.05). Caponization could dramatically increase relative abdominal fat (506%; P < 0.05). The shams had higher tibia weight and biomechanical properties, such as maximum bone strength and bending moment values than the capons (P < 0.05). Tibia biomechanical properties were reduced by estrogen treatment (P < 0.05). The females obtained the lowest biomechanical value in all treatments (P < 0.05). Histological examination revealed cavity formation in the cortical bone of estrogen‐treated capons and female chickens, which suggested that estrogen reduced bone biomechanical properties by destroying its structural integrity.  相似文献   
105.
106.
Hemorrhagic fever with renal syndrome (HFRS) comprises a variety of clinically similar diseases of viral etiology that are endemic to and sporadically epidemic throughout the Eurasian continent and Japan. Although HFRS has not been reported in North America, viruses that are antigenically similar to HFRS agents were recently isolated from rodents in the United States. Examination and comparison of eight representative isolates from endemic disease areas and from regions with no known associated HFRS indicate that these viruses represent a new and unique group that constitutes a separate genus in the Bunyaviridae family of animal viruses.  相似文献   
107.
A simple negative feedback loop of interacting genes or proteins has the potential to generate sustained oscillations. However, many biological oscillators also have a positive feedback loop, raising the question of what advantages the extra loop imparts. Through computational studies, we show that it is generally difficult to adjust a negative feedback oscillator's frequency without compromising its amplitude, whereas with positive-plus-negative feedback, one can achieve a widely tunable frequency and near-constant amplitude. This tunability makes the latter design suitable for biological rhythms like heartbeats and cell cycles that need to provide a constant output over a range of frequencies. Positive-plus-negative oscillators also appear to be more robust and easier to evolve, rationalizing why they are found in contexts where an adjustable frequency is unimportant.  相似文献   
108.
Cells from a rat pituitary tumor cell line will respond in vitro to physiological concentrations of L-thyroxine and L-triiodothyronine. The cells are grown in a cultutre medium that contains serum from a hypothyroid calf. Dose-response relationships of a vacriety of thyronine derivatives indicate that this system has a specificity of response which is similar to that observed in vitro.  相似文献   
109.
110.
BackgroundPseudorabies virus (PRV) infection leads to high mortality in swine. Despite extensive efforts, effective treatments against PRV infection are limited. Furthermore, the inflammatory response induced by PRV strain GXLB-2013 is unclear.ObjectivesOur study aimed to investigate the inflammatory response induced by PRV strain GXLB-2013, establish an inflammation model to elucidate the pathogenesis of PRV infection further, and develop effective drugs against PRV infection.MethodsKunming mice were infected intramuscularly with medium, LPS, and different doses of PRV-GXLB-2013. Viral spread and histopathological damage to brain, spleen, and lung were determined at 7 days post-infection (dpi). Immune organ indices, levels of reactive oxygen species (ROS), nitric oxide (NO), and inflammatory cytokines, as well as levels of activity of COX-2 and iNOS were determined at 4, 7, and 14 dpi.ResultsAt 105–106 TCID50 PRV produced obviously neurological symptoms and 100% mortality in mice. Viral antigens were detectable in kidney, heart, lung, liver, spleen, and brain. In addition, inflammatory injuries were apparent in brain, spleen, and lung of PRV-infected mice. Moreover, PRV induced increases in immune organ indices, ROS and NO levels, activity of COX-2 and iNOS, and the content of key pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, tumor necrosis factor-α, interferon-γ and MCP-1. Among the tested doses, 102 TCID50 of PRV produced a significant inflammatory mediator increase.ConclusionsAn inflammatory model induced by PRV infection was established in mice, and 102 TCID50 PRV was considered as the best concentration for the establishment of the model.  相似文献   
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