Determination of isoflavones in red clover by capillary electrophoresis with electrochemical detection

Capillary electrophoresis with electrochemical detection (CE-ED) was employed to analyze isoflavones in red clover (Trifolium pratense). The effects of potential of working electrode, pH and concentration of running buffer, separation voltage and injection time on CE-ED were investigated. Operated in a wall-jet configuration, a 300 microm diameter carbon-disk electrode was used as the working electrode, which exhibits a good response at +0.85 V (versus saturated calomel electrode) for the analytes. The analytes could be separated in a 50 mmol/l borate buffer (pH 9.5) within 25 min. The response was linear over three orders of magnitude with detection limit (S/N=3) ranging from 2x10(-5) mg/ml to 5x10(-5) mg/ml for the analytes. This method has been used for the determination of daidzein, genistein and biochanin A in red clover with satisfactory results.     

水稻重要农艺性状的QTL分析和主效QTL近等基因系的构建

水稻许多重要农艺性状都是数量性状,水稻遗传改良的大部分工作就是改良这些数量性状。1980年以后,随着分子标记的出现,水稻高密度遗传连锁图谱的大量绘制,各种作图群体的迅猛构建,功能强大的各种统计学软件的快速开发,全基因组序列测序的完成,特别是多个QTL精细定位和先后克隆,使得我们对数量性状的认识得到了长足的进步,QTL的研究正在走进新时代。     

Microbial uptake of low‐molecular‐weight organic substances out‐competes sorption in soil

Low‐molecular‐weight organic substances (LMWOS) such as amino acids, sugars and carboxylates, are rapidly turned over in soil. Despite their importance, it remains unknown how the competition between microbial uptake and sorption to the soil matrix affects the LMWOS turnover in soil solution. This study describes the dynamics of LMWOS fluxes (10 µm ) in various pools (dissolved, sorbed, decomposed to CO₂ and incorporated into microbial biomass) and also assesses the LMWOS distribution in these pools over a very wide concentration range (0.01–1000 µm ). Representatives of each LMWOS group (glucose for sugars, alanine for amino acids, acetate for carboxylates), uniformly ¹⁴C‐labelled, were added to sterilized or non‐sterilized soil and analysed in different pools between 1 minute and 5.6 hours after addition. LMWOS were almost completely taken up by microorganisms within the first 30 minutes. Surprisingly, microbial uptake was much faster than the physicochemical sorption (estimated in sterilized soil), which needed 60 minutes to reach quasi‐equilibrium for alanine and about 400 minutes for glucose. Only acetate sorption was instantaneous. At a concentration of 100 µm , microbial decomposition after 4.5 hours was greater for alanine (76.7 ± 1.1%) than for acetate (55.2 ± 0.9%) or glucose (28.5 ± 1.5%). In contrast, incorporation into microbial biomass was greater for glucose (59.8 ± 1.2%) than for acetate (23.4 ± 5.9%) or alanine (5.2 ± 2.8%). Between 10 and 500 µm , the pathways of the three LMWOS changed: at 500 µm , alanine and acetate were less mineralized and more was incorporated into microbial biomass than at 10 µm , while glucose incorporation decreased. Despite the fact that the LMWOS concentrations in soil solution were important for competition between sorption and microbial uptake, their fate in soil is mainly determined by microbial uptake and further microbial transformations. For these substances, which represent the three main groups of LMWOS in soil, the microbial uptake out‐competes sorption.     

The effect of lead poisoning on hematologic and biochemical values in trumpeter swans and Canada geese

BACKGROUND: Lead is a persistent contaminant in the environment, and waterfowl are susceptible to lead toxicity from ingestion of lead pellets and fishing weights. Lead affects numerous physiologic processes through inhibition of enzyme activity and protein function, but its effects on commonly assessed avian blood values are incompletely understood. OBJECTIVES: Our aim was to evaluate hematologic and biochemical changes associated with blood lead concentrations in trumpeter swans and Canada geese. METHODS: Data for CBCs, plasma biochemical profiles (total protein, albumin, glucose, cholesterol, total bilirubin, calcium, phosphorus, gamma-glutamyltransferase [GGT], aspartate aminotransferase, lactate dehydrogenase, glutamate dehydrogenase, creatine kinase, amylase, and lipase), and whole blood lead concentrations were retrospectively analyzed for 69 trumpeter swans and 52 Canada geese. Laboratory data obtained prospectively from an additional 20 trumpeter swans also were included. RBC morphology was semiquantitated in blood smears from 70 of the birds. Data were analyzed initially by ANOVA and covariance. A statistical model then was constructed to determine the relationship between each parameter and lead concentration. RESULTS: In both avian species, PCV, hemoglobin concentration, and MCHC decreased significantly (P < .05) with increasing blood lead concentration. Uric acid concentration and GGT activity were increased in trumpeter swans and phosphorus concentration was decreased in Canada geese in association with high blood lead concentration (P < .05). CONCLUSIONS: Lead toxicosis induced significant changes in the values of commonly measured hematologic parameters in waterfowl. These changes may be useful indicators of severe lead intoxication during routine laboratory assessment. Changes in clinical chemistry values, although statistically significant, were too inconsistent to serve as indicators of lead toxicosis.     

Comparative study of renin-containing cells. Histological approaches

The juxtaglomerular apparatus is known to be the functional unit of renin control. In the present review, the author will describe the comparative characteristics of renin-containing (RC) cells as well as extrarenal distribution, paying special attention to developmental and topographical approaches. The characteristic locality of RC cells suggests that the secretion of renin is performed at a site beside the adventitia or via the glomerular capillaries. Ontogenetical and phylogenetical investigations of RC cells have provided interesting findings on their morphogenesis. Analysis of the endocrine kidney after unilateral obstruction of the ureter provides some findings about the origin of RC cells and the processing of renin granules. Observation of developing adrenal renin suggests that there is important involvement of angiotensin II produced by renin synthesis in the morphogenesis of the adrenal gland in the fetal stage. Coagulating gland (CG) renin is characterized by testosterone-regulated and exocrine mechanisms. Recently, all or some of the components of the renin-angiotensin system (RAS) have been reported to be synthesized and secreted outside of classical organs or tissues. In the future, the real function of local RAS will be clarified by using gene targeting in mice.     

Growth and Nutrient Content of Trifoliate Orange Seedlings Influenced by Arbuscular Mycorrhizal Fungi Inoculation in Low Magnesium Soil

A pot experiment was conducted to examine the effects of arbuscular mycorrhizal fungi, Glomus versiforme, G. mosseae, and G. intraradices on growth and nutrition of trifoliate orange (Poncirus trifoliata) seedlings under magnesium (Mg)-nontreated and Mg-treated conditions. Whether treated with Mg or not, G. versiforme inoculation significantly enhanced the growth and concentrations of Mg, phosphorus, calcium, potassium, zinc, and copper in shoots or roots, and activities of acid phosphatase, catalase, invertase, and urease in rhizosphere soils. Additionally, there were higher levels of chlorophyll, proline, soluble sugar and protein in leaves, root viability, superoxide dismutase, peroxidase and catalase in leaves and roots, but lower malondialdehyde content in leaves and roots of mycorrhizal seedlings than non-mycorrhizal ones. Data demonstrated that G. versiforme-inoculated citrus seedlings exhibited higher levels of soil enzymes, osmoregulation, and antioxidant matters, leading to improvement of growth and nutrition of seedlings in low Mg soil.     

Immunogenicity of infectious bursal disease viruses in chickens.

Cross-protective properties of infectious bursal disease viruses (IBDVs) were studied. Viruses represented different subtypes of serotype 1, including recently isolated viruses (variants), and a serotype 2 virus. Chickens were vaccinated at 3 weeks of age with inactivated vaccines containing 10(5), 10(6), 10(7), or 10(8) mean tissue-culture infectious dose of a given virus and challenged 2 weeks later using either 10(2) or 10(3.5) mean embryo infectious dose (EID50) of either a standard virus or a variant serotype 1 virus. Protection was evaluated at 5 and 10 days post-challenge, based on gross and microscopic lesions, body weight, and bursa/body-weight ratios. The serotype 2 virus did not confer protection on birds challenged with the serotype 1 viruses. Vaccines made of variant viruses at the low doses protected chickens challenged with the high or low doses of either the standard or the variant viruses. Vaccines made of the standard or variant strains at low doses protected against high or low challenge doses of the standard strain. Vaccines made of the high dose of any of the standard strains protected chickens against the variant virus when the low challenge dose (10(2) EID50) was used, but not when the high challenge dose (10(3.5) EID50) was used. The lowest dose of the standard viruses vaccines required to confer protection against the variant virus varied depending on the strain. Results indicated that protection depended on the strain and dose of both the vaccine and challenge viruses and that the variant strains and standard strains share a common protective antigen(s).