Vasopressin and the transmission of paternal behavior across generations in mated, cross-fostered Peromyscus mice.

The role of arginine vasopressin (AVP) in the nongenomic transfer of paternal behavior from fathers to offspring was examined in Peromyscus. Male California mice (P. californicus) exposed to fewer retrievals by white-footed mouse (P. leucopus) foster parents displayed fewer retrievals of biological offspring. In contrast, white-footed mice were retrieved equally rarely by California mouse foster parents and by biological parents and displayed no changes in pup retrieval behavior. AVP-immunoreactive staining in the bed nucleus of the stria terminalis may predict paternal behavior because it correlated positively with retrievals and with a score consisting of huddling, grooming, and time inside the nest. The authors discuss AVP as a possible mechanism by which early experience shapes adult paternal behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

野生型与突变型钝齿棒杆菌生物合成精氨酸基因簇arg JBDFR的生物信息学比较

本文设计四对特异性引物分别扩增了野生型和突变型钝齿棒杆菌精氨酸生物合成基因簇argCJBDFR,对其中发生突变的基因argJ、argB及argF的变化进行了生物信息学比较,并分析了这些突变可能对精氨酸产量提高的贡献,为采用基因工程手段改良菌种提供有益的信息和指导。     

Wine composition plays an important role in the control of carcinogenic precursor formation by Lactobacillus hilgardii X1B

BACKGROUND: Lactobacillus hilgardii, a wine lactic acid bacterium, is able to use arginine, through the arginine deiminase pathway with the formation of citrulline, a precursor of the carcinogen ethyl carbamate. The influence of different Argentine wine varieties (Merlot, Cabernet Sauvignon and Malbec), on bacterial growth and arginine metabolism was examined. Furthermore, the effect of different components normally present in wines on the enzyme activities of the arginine deiminase system was determined. RESULTS: Malbec wine under all conditions assayed (33, 50 and 100% supplemented wine:basal media) showed higher arginine consumption and citrulline production than the other wines, as well as the highest bacterial growth and survival of Lactobacillus hilgardii X₁B. Glucose and L ‐malic inhibited both arginine deiminase enzymes while fructose and citric acid only inhibited arginine deiminase. The red wines assayed in this study had different composition, and this is an explanation for the different behavior of the bacterium. CONCLUSION: The highest citrulline production in Malbec wine could be correlated with its lower concentrations of glucose, fructose, citric and phenolic acid than the other wines. Therefore, a wine with lower concentration of these sugars and acids could be dangerous due to the formation of ethyl carbamate precursors. Copyright © 2012 Society of Chemical Industry     

Kinetics of Lysine and Other Amino Acids Loss During Extrusion Cooking of Maize Grits

ABSTRACT: Maize grits were extrusion-cooked in a conical, counter-rotating twin-screw extruder at different barrel temperatures, feed moistures, and screw speeds. Residence time distribution was measured by a dye tracer technique. Experiments with lysine-fortified maize grits showed a 1st order reaction for lysine loss. A detailed kinetic study has been performed for the losses during extrusion cooking of lysine, cystine, and arginine. The 1st-order rate constants were dependent mainly on product temperature and feed moisture, whereas screw speed had no influence. Activation energy of lysine, arginine, and cystine loss was 127, 68, and 76 kJ/mol, respectively. Shear stress significantly affected the rate constants of amino acids loss in extrusion cooking.     

L-精氨酸席夫碱钴(Ⅱ)配合物的合成及结构研究

以2,4-二羟基苯甲醛-L-精氨酸席夫碱为配体,合成了钴(Ⅱ)的配合物.通过元素分析、TG-DTA、IR及电子光谱研究了配合物的组成和结构.     

酶法转化制备L-瓜氨酸

利用粪链球菌精氨酸脱亚胺酶转化L-精氨酸制备L-瓜氨酸。考察了菌龄、转化温度等多种因素对精氨酸脱亚胺酶活力的影响。酶法制备L-瓜氨酸的最适工艺条件是:菌体发酵时间20 h,转化温度37℃,转化液起始pH为6.0,ρ〔十六烷基三甲基溴化铵(CTAB)〕=0.3 g/L使酶活提高了414%。c(Co2+)=10-3mol/L使酶活增高约50%,c(Cu2+)=10-2mol/L或c(Zn2+)=10-2mol/L使酶活下降约50%。Ca2+、Mg2+和Mn2+对酶活影响较小。     

Characteristics of functionalized nano-hydroxyapatite and internalization by human epithelial cell

Hydroxyapatite is the main inorganic component of biological bone and tooth enamel, and synthetic hydroxyapatite has been widely used as biomaterials. In this study, a facile method has been developed for the fabrication of arginine-functionalized and europium-doped hydroxyapatite nanoparticles (Arg-Eu-HAP). The synthesized nanoparticles characterized by transmission electron microscopy, X-ray diffractometry, Fourier transform infrared, and Zeta potential analyzer. Its biological properties with DNA binding, cell toxicity, cell binding and intracellular distribution were tested by agarose gel electrophoresis assay, flow cytometry, and fluorescence microscope and laser scanning confocal microscope. The synthesized Arg-Eu-HAP could effectively bind DNA without any cytotoxicity and be internalized into the cytoplasm and perinuclear of human lung epithelial cells.