Biochemical properties,molecular characterizations,functions, and application perspectives of phytases

As a kind of enzyme widely existing in eukaryotic species, especially in grains and oil seeds, phytases play an important role in the degradation of some phosphates containing organic molecules. So far, phytases derived from various species have been successfully used as animal feed additives. It has also been experimentally verified that phytases have a potential use in generating crop germplasm with high phosphorus use efficiency, based on their biochemical role in releasing Pi from the phytate and its derivatives. In this paper, the biochemical properties, molecular characterizations, functions and the potential application perspective of phytases are reviewed and commented on, aiming at the further exploration of the biochemical and molecular characterizations, and promotion of the application of phytases, a kind of important enzyme possessing potential use in animal feeding and creation of high P use crop cultivars, in the future.     

Effects of Neutral Phytase Supplementation on Biochemical Parameters in Grass Carp,Ctenopharyngodon idellus,and Gibel Carp,Carassius auratus gibelio,Fed Different Levels of Monocalcium Phosphate

Two 8‐wk studies were conducted to evaluate the effects of neutral phytase supplementation on hemato‐biochemical status, liver biochemical parameter, and intestinal digestive enzyme activity of grass carp, Ctenopharyngodon idellus, and gibel carp, Carassius auratus gibelio, fed with different levels of monocalcium phosphate (MCP). The control diet was prepared with 2% MCP but without phytase (P2.0). The other three experimental diets were prepared with the addition of 1.5, 1.0, and 0.5% MCP, respectively, when supplemented with 500 U/kg neutral phytase in each diet and designated as PP1.5, PP1.0, and PP0.5, respectively. The results indicated that the serum alkaline phosphatase (ALP), alanine transaminase (ALT), and aspartate transaminase (AST) activities, as well as the albumin (ALB) content were increased in grass carp (P < 0.05) and gibel carp (P > 0.05) fed with phytase‐supplemented diets. Meanwhile, the serum cholesterol, high‐density lipoprotein, and total protein contents of the two species of fish were increased in comparison to the control. In addition, dietary phytase inclusion did not significantly affect hepatic ALP, ALT, and AST activities in the two species of carp fed with different levels of MCP. Amylase activity increased in foregut and hindgut of both species when fed with the phytase‐supplemented diets while lipase activity was reduced in the foregut and hindgut in both fish. This study suggests that neutral phytase supplementation increases serum ALP, ALT, and AST activities but does not notably affect these enzyme activities in the liver of the two species of carp when fed different levels of MCP. On the other hand, amylase activity increased while lipase activity was reduced in the intestine of the species of carp fed with phytase‐supplemented diets.     

高效液相法测定普洱茶焙烤制品中儿茶素及咖啡碱含量的研究

为准确测定普洱茶经焙烤后有效物质儿茶素及咖啡碱的保留率,建立了高效液相法,采用70%甲醇提取液提取茶焙烤制品中的儿茶素,并使用C18反相色谱柱,以乙酸乙腈-乙酸水为流动相进行梯度洗脱,流速为1 mL/min;在波长为270 nm下经紫外分光法检测,结果表明:普洱茶粉的有效成分在焙烤过程中的保留率高,其中总儿茶素的平均保留率达90.55%,咖啡碱的平均保留率高达99.46%,因此该检测方法具有简便、准确、分离效果好的优点,适用于检测茶焙烤食品中儿茶素的含量。     

不同剂量阿苯达唑治疗鼠旋毛虫病效果初探

使用不同剂量阿苯达唑对人工感染旋毛虫的小白鼠进行疗效试验,观察其不同剂量的杀虫效果.结果表明：应用阿苯达唑20 mg/（kg·d）×7治疗鼠旋毛虫病有很好的治疗效果,为阿苯达唑临床应用提供科学参考.     

Identification of molecular markers linked to the genes for purple grain color in wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis>)

Pericarp color in wheat is an important trait related to nutrients and health benefits. Identification of molecular markers closely linked to the grain color genes will help utilize pericarp trait in wheat breeding. Genetic studies involving F₁, F₂, and F₃ populations from the cross Jizi 439 (purple grain)/Gao8901 (white grain) showed that the purple grain color was controlled by two genes. By using the bulked segregant analysis (BSA) approach, two DNA pools were established from the dark purple-grain and white-grain plants respectively. Among the 230 pairs of microsatellite primers used in this study, two markers showed polymorphism in DNA pools, parents, F₁ and F₂ populations. Linkage analysis indicated that the two markers Xgwm47 and Xgwm155 were linked with two purple pigment genes. One of the purple pigment genes is located on chromosome 2AS and is 34.7cM away from the marker Xgwm47, whereas another gene is mapped on 3AL with 14.7cM away from marker Xgwm155.     

浅析新时期我国农业推广中存在的问题及科学应对策略

依据我国新时期农业发展的优势环境展开了农业推广进程中普遍存在问题的深入分析,并针对目前农业发展中重科研、轻推广,机制建立不健全等现状制定了切实可行的应对策略,对促进我国农业的成果转化与合理推广有重要的实践意义。     

乡镇级空间发展功能区划方法探讨——以广西贵港市港南区八塘镇为例

以广西贵港市港南区八塘镇为例，采用主成分分析法、GIS技术和SPSS13．0软件对生态环境价值、经济发展基础、自然资源价值3个主因子进行综合得分测算，得到经济一生态一资源组合三维坐标，最终形成空间开发功能区划，将全镇22个行政村划分为6类。6类空间开发功能区划中，重点发展区域和适度发展区域主要分布在八塘村、新陆村、苏湾村、新蒙村、湿村、大新村、高新村，这类区域的交通区位较优越、经济发展基础较坚实、生态环境敏感性较低，宜作为城镇和产业发展的主要空间载体；控制开发区域主要分布在高北村、高岭村、苏岗村、木龙村、振新村，这类区域的经济发展基础中等，主要以农业种植业为主，生态环境敏感性中等，且临近重点开发区域，需在一定限制下进行开发；灰色弹性区域主要分布在横岭村、三板村、学山村、山泉村、新花村，这类区域的经济发展基础和生态环境敏感性均较低，但由于自然资源条件较好，交通区位较优越，具有潜在的经济发展优势，作为城镇和产业的后备发展用地；适度保护区域和重点保护区域主要分布在高浪村、岑西村、新安村、新舍村，这类区域生态环境较脆弱，经济发展基础较低，应按照“保护优先，集约开发”的原则发展。