茶籽中脂肪酸的组成及其生物活性脂肪酸对高糖胁迫下RF/6A细胞生长的影响

采用气相色谱(GC)对茶籽的脂肪酸组成进行分析,并研究了活性脂肪酸对高浓度葡萄糖胁迫下RF/6A细胞生长的影响及其与葡萄糖对RF/6A细胞脂肪酸代谢的调节。结果表明,油酸与亚油酸为茶籽中含量最高的脂肪酸;而茶籽中脂肪酸的组成与其品种和产地有密切关系。亚油酸与亚麻酸对高浓度葡萄糖诱导的RF/6A细胞过度增殖有抑制作用。亚油酸、亚麻酸及棕榈酸对RF/6A细胞的脂肪酸代谢均具有调节作用。     

Interception of excited vibrational quantum states by O2 in atmospheric association reactions

Bimolecular reactions in Earth's atmosphere are generally assumed to proceed between reactants whose internal quantum states are fully thermally relaxed. Here, we highlight a dramatic role for vibrationally excited bimolecular reactants in the oxidation of acetylene. The reaction proceeds by preliminary adduct formation between the alkyne and OH radical, with subsequent O(2) addition. Using a detailed theoretical model, we show that the product-branching ratio is determined by the excited vibrational quantum-state distribution of the adduct at the moment it reacts with O(2). Experimentally, we found that under the simulated atmospheric conditions O(2) intercepts ~25% of the excited adducts before their vibrational quantum states have fully relaxed. Analogous interception of excited-state radicals by O(2) is likely common to a range of atmospheric reactions that proceed through peroxy complexes.     

Transmission, characterization, and serology of a luteovirus associated with yellow leaf syndrome of sugarcane

ABSTRACT A previously uncharacterized luteovirus was associated with one form of yellow leaf syndrome (YLS), a widespread disease of sugarcane (Saccharum sp.). The virus was named Sugarcane yellow leaf luteovirus (ScYLV), and was identified in major sugarcane-producing areas of the world. Typical disease symptoms were reproduced when ScYLV was transmitted by Melanaphis sacchari or Rhopalosiphum maidis from infected to healthy sugarcane, suggesting that this virus may be the causal agent of one form of YLS. The only known hosts of ScYLV are Saccharum and Erianthus spp. Virions of ScYLV were 24 to 29 nm in diameter in sodium phosphotungstate at pH 5.0, had a buoyant density of 1.30 g/cm(3) in Cs(2)SO(4), and contained a 5.8-kb genomic ssRNA. The capsid protein had an estimated relative molecular mass of 27 kDa and was not glycosylated. A polyclonal rabbit antiserum raised against ScYLV did not detect any of eight other luteoviruses by enzyme-linked immunosorbent assay or immunosorbent electron microscopy, but in immunoblot assays, antibodies to ScYLV detected the RPV serotype of Barley yellow dwarf luteovirus. It is concluded that ScYLV is a previously undescribed luteovirus that is biologically and serologically distinct from other members of the group and may be the causal agent of one form of YLS of sugarcane.     

Variation in virus populations and growth characteristics of two sugarcane cultivars naturally infected by Sugarcane yellow leaf virus in different geographical locations

Two sugarcane cultivars (R570 and SP71-6163) naturally infected by Sugarcane yellow leaf virus (SCYLV) were each imported from several geographical locations into a sugarcane yellow leaf-free environment (Montpellier, France). Plants were grown as plant cane for 5–6 months and the experiment was repeated for three consecutive years (2003–2005) in a greenhouse. Several sugarcane-growth and disease characteristics were monitored to identify variation in pathogenicity of SCYLV. Depending on their geographical origin, sugarcane cvs R570 and SP71-6163 were infected by SCYLV genotypes BRA-PER or REU, or a mixture of the two. Severity of symptoms did not vary between plants of cv. R570, but variation in disease severity between plants of cv. SP71-6163 from different geographical locations suggested the occurrence of pathogenic variants of SCYLV. For each sugarcane cultivar, differences in stalk length, number of stalk internodes, virus titre in the top visible dewlap leaf, and percentage of infection of leaf and stalk phloem vessels were also found between plants from different geographical origins. However, these differences were not always reproducible from one year to another, suggesting occurrence of different plant responses to SCYLV isolates under varying environmental conditions.     

Use of different microbial probiotics in the diet of rohu,Labeo rohita fingerlings: effects on growth,nutrient digestibility and retention,digestive enzyme activities and intestinal microflora

Six iso‐nitrogenous (350 g protein kg^?1) and iso‐caloric (4100 kcal kg^?1) diets with or without probiotics supplementation namely T₁ (Basal feed (BF) without probiotics; control), T₂ (BF + Bacillus subtilis and Lactococcus lactis), T₃ (BF + L. lactis and Saccharomyces cerevisiae), T₄ (BF + B. subtilis and S. cerevisiae), T₅ (BF + B. subtilis, L. lactis and S. cerevisiae) and T₆ (BF + heat‐killed bacteria of B. subtilis, L. lactis and S. cerevisiae) were fed to Labeo rohita fingerlings (6.0 ± 0.06 g) for 60 days in triplicate tanks (30 fish per tank). In all probiotic‐supplemented diets, the probiotic concentration was maintained at 10¹¹ cfu kg^?1 feed. After 60 days of culture, the fish fed combination of three probiotics at equal proportion (T₅) had higher (P < 0.05) growth, protein efficiency ratio, nutrient retention and digestibility and lower (P > 0.05) feed conversion ratio over other treatment groups. Total heterotrophic bacterial population in intestine was drastically reduced on 15th and 30th days of sampling than the initial value (0 day of sampling) for T₃, T₄ and T₅ groups. Except T₆, the gut colonization of respective probiotics, which were supplemented through the diets, was also increased up to 30 days of culture of fish and thereafter remained constant.     

Immune response, growth and survival of Labeo rohita fingerlings fed with levamisole supplemented diets for longer duration

The study was to determine the effect of long-term administration of different dosages of levamisole on growth, immune response and disease resistance against Aeromonas hydrophila & Edwardsiella tarda in Labeo rohita fingerlings. Fish were fed with four different dosages of levamisole (0, 125, 250 and 500 mg kg⁻¹ diet) for 56 days. Different serum biochemical and haematological parameters such as serum total protein content, albumin content, globulin content, albumin/globulin ratio, glucose content, leucocytes count; cellular immune parameters including superoxide anion production, phagocytic activities, lymphokine production index; humoural immune parameters including lysozyme, complement and serum bactericidal activities were evaluated after 14 days interval. After 56 days, fish were divided into two subgroups under each treatment group for challenge with pathogens A. hydrophila and E. tarda . The cumulative mortality (%) and agglutinating antibody titre was recorded on 28th day postchallenge. WBC count, phagocytic ratio, lymphokine production index, lysozyme activity and serum bactericidal activity were increased upon administration of levamisole dosages for long term. However, the growth performance and survival against pathogens was not significantly changed over 56 days administration of levamisole. But incorporation of moderate dosage of levamisole for 42 days results better immune response without effect on growth and survival of L. rohita fingerlings.