Microbial and soil parameters in relation to N mineralization in soils of diverse genesis under differing management systems

 Oregon soils from various management and genetic histories were used in a greenhouse study to determine the relationships between soil chemical and biological parameters and the uptake of soil mineralized nitrogen (N) by ryegrass (Lolium perenne L.). The soils were tested for asparaginase, amidase, urease, β-glucosidase, and dipeptidase activities and fluorescein diacetate hydrolysis. Microbial biomass carbon (C) and N as well as metabolic diversity using Biolog GN plates were measured, as were total soil N and C, pH, and absorbance of soil extracts at 270 nm and 210 nm. Potentially mineralizable N (N₀) and the mineralization rate constant (k) were calculated using a first order nonlinear regression model and these coefficients were used to calculate the initial potential rate of N mineralization (N₀ k). Except for Biolog GN plates, the other parameters were highly correlated to mineralized N uptake and each other. A model using total soil N and β-glucosidase as parameters provided the best predictor of mineralized N uptake by ryegrass (R ² =0.83). Chemical and biological parameters of soils with the same history of formation but under different management systems differed significantly from each other in most cases. The calculated values of the initial potential rate of mineralization in some cases revealed management differences within the same soil types. The results showed that management of soils is readily reflected in certain soil chemical and biological indicators and that some biological tests may be useful in predicting N mineralization in soils. Received: 31 January 1997     

胶体金免疫快速检测卡与酶联免疫法检测小麦中呕吐毒素的技术比较

以2016年新上市小麦为检测对象,采用胶体金免疫快速检测卡法和酶联免疫法对小麦中呕吐毒素含量进行测定,比较2种方法的符合率。结果表明:2种方法测定结果符合率达到93.4%。胶体金免疫快速检测卡操作简便快速,成本低,适用于新粮上市现场入库把关大量样品的快速初筛;而酶联免疫法检测时间较长,成本更高,更适合经胶体金免疫快速检测卡初筛后呈阴性样品的确证以及呕吐毒素含量的准确定量。     

河北省旱碱麦品质和抗性相关基因的KASP标记检测

利用12个小麦品质、抗病和抗逆等相关的KASP标记,对河北省育成的部分旱碱麦和农家种(54份)进行KASP标记检测.结果表明,在品质方面,有15份材料含有Glu-D1基因的高分子量麦谷蛋白亚基5+10,有32份材料是Glu-A1基因的Ax1 orAx2*强筋单倍型.在抗病性方面,有25份含有抗叶锈病基因Lr34,有27...     

Mycotoxin detection——Recent trends at global level

Mycotoxin contamination in agro-food systems has been a serious concern globally during the last few decades. Mycotoxins are toxic secondary metabolites produced by fungi when they grow in agro-food products and feedstuff. Several detection techniques have been developed in recent years to detect mycotoxins in the food and feed effectively. HPLC based techniques are very common in usage in the laboratories for the testing of mycotoxins. In recent years,immuno-based assays is widely used and have been reported at large due to its sensitivity and limited detection time. Immuno assay-based kits were developed effectively to be used in the fields and in storage systems to detect the mycotoxin levels. Microarray-based immunoassays developed in the recent years could simultaneously detect aflatoxin,ochratoxin,and zearalenone with the higher sensitivity. Aptamer-based assays could target the detection of ochratoxin and aflatoxins and fumonisins at high specificity in food products. In recent years,several assays reported for the simultaneous multiple detection of different mycotoxin was based on HPLC and LC-MS/MS. There is a need for the use of these advanced technologies in the commercial scale.     

β-氨基丁酸诱导马铃薯对晚疫病的抗性组织化学及信号传导途径分析

【目的】β-氨基丁酸（BABA）田间或离体叶片喷洒能够有效诱导马铃薯防卫反应,增强对晚疫病的抗性。研究从组织化学层面进一步探究BABA诱导马铃薯晚疫病抗性过程中诱发的防卫反应及相关信号途径,为深入研究BABA诱导马铃薯产生晚疫病抗性的可能机制奠定基础。【方法】用4 mmol?L-1 BABA或蒸馏水（对照,Mock）喷洒马铃薯植株叶片,3 d后取离体叶片接种晚疫病菌（Phytophthora infestans）,接种后不同时间用打孔器取接种点叶盘用于织化学染色和过敏反应（HR）观察。采用二氨基联苯胺（DAB）组织化学染色方法检测接种点周围活性氧（H2O2）累积情况;叶盘用苯胺蓝（aniline blue）染色,然后在荧光显微镜下观察接种点周围胼胝质积累和表皮细胞HR发生情况;利用干涉了StCOI1（阻断了茉莉酸JA信号传导途径）和超量表达细菌水杨酸羟化酶基因NahG（阻断了水杨酸SA信号传导途径）的转基因马铃薯株系为材料,通过研究BABA能否在这些特殊马铃薯材料上有效诱导晚疫病抗性,进而推断BABA诱导马铃薯晚疫病抗性可能参与的信号途径。【结果】用清水作为空白接种时,Mock和BABA预处理叶片各时间点均未观察到H2O2积累,而病原菌接种处理24 h后,Mock和BABA预处理叶片接种点周围都出现H2O2积累,随着病原诱导时间的延长,H2O2积累增强。但是,BABA预处理叶盘中接种点周围H2O2累积比对照提前12 h,且累积量显著强于对照。苯胺蓝染显示Mock和BABA预处理叶片在接种清水时检测不到胼胝质的沉积,而接种晚疫病菌24 h后,Mock和BABA预处理叶片上均观察到胼胝质的沉积,BABA预处理叶片在侵染点及其附近胼胝质积累量要显著高于对照。荧光显微观察结果显示,BABA预处理和Mock叶片晚疫病接种点周围表皮细胞均有HR发生,BABA预处理叶片早在接种24 h后,接种点周围就已出现HR反应;接种48 h时,BABA预处理85%叶盘的接种点周围表皮细胞出现HR,而Mock叶片只有30%叶盘上观察到HR,BABA预处理叶片HR发生频率比Mock叶片高出55%。BABA不能在超量表达NahG的马铃薯叶片上有效诱发抗性,但能够在干涉了StCOI1的马铃薯叶片上正常诱导产生抗性。【结论】BABA能够从H2O2和胼胝质累积以及HR发生多个层面有效诱发马铃薯基础防御反应,BABA预处理能够在病原菌侵染点周围显著提高胼胝质和H2O2积累水平,诱发接种点发生较高频率的HR,从而提高马铃薯对晚疫病的抗性;BABA诱导马铃薯对晚疫病的抗性依赖水杨酸信号传导途径,但不依赖茉莉酸信号传导途径。     

458份小麦品种(系)抗病性状功能基因的KASP标记检测

[目的]研究不同小麦品种(系)抗病性状功能基因的分布状态,分析小麦品种(系)的抗病功能基因,为小麦抗病育种提供理论依据.[方法]利用KASP技术通过1个抗白粉病分子标记(Pm21)、1个抗条锈病分子标记(Yr15)和2个抗叶锈病分子标记(Lr14、Lr68),检测458份小麦品种(系).[结果]筛选出携带Pm21标记材...     

Canine parvovirus--a review of epidemiological and diagnostic aspects, with emphasis on type 2c

Canine parvovirus type 2 (CPV-2) emerged in late 1970s causing severe epizootics in kennels and dog shelters worldwide. Soon after its emergence, CPV-2 underwent genetic evolution giving rise consecutively to two antigenic variants, CPV-2a and CPV-2b that replaced progressively the original type. In 2000, a new antigenic variant, CPV-2c, was detected in Italy and rapidly spread to several countries. In comparison to the original type CPV-2, the antigenic variants display increased pathogenicity in dogs and extended host range, being able to infect and cause disease in cats. Epidemiological survey indicate that the newest type CPV-2c is becoming prevalent in different geographic regions and is often associated to severe disease in adult dogs and also in dogs that have completed the vaccination protocols. However, the primary cause of failure of CPV vaccination is interference by maternally derived immunity. Diagnosis of CPV infection by traditional methods has been shown to be poorly sensitive, especially in the late stages of infections. New diagnostic approaches based on molecular methods have been developed for sensitive detection of CPV in clinical samples and rapid characterisation of the viral type. Continuous surveillance will help assess whether there is a real need to update currently available vaccines and diagnostic tests.     

Arginine ammonification and L‐glutaminase assays as rapid indices of corn nitrogen availability

Increasing use of N fertilizer for crop production necessitates more rapid estimates on N provided by the soil in order to prevent under‐ or overfertilization and their adverse effect on plant nutrition and environmental quality. A study was conducted to investigate the responses of arginine ammonification (AA), L‐glutaminase activity (LG), soil N–mineralization indices, corn (Zea mays L.) crop–yield estimation, and corn N uptake to application of organic amendments. The relationships between corn N uptake and the microbial and enzymatic processes which are basically related to N mineralization in soil were also studied. The soil samples were collected from 0–15 cm depth of a calcareous soil that was annually treated with 0, 25, or 100 Mg ha^–1 (dry‐weight basis) of sewage sludge and cow manure for 7 consecutive years. Soil total N (TN), potentially mineralizable N (N₀), and initial potential rates of N mineralization (kN₀) were significantly greater in sewage sludge–treated than in cow manure–treated soils. However, the amendment type did not influence soil organic C (SOC), AA, LG, and anaerobic index of N mineralization (N_ana). The application rates proportionally increased N‐availability indices in soil. Corn N concentration and uptake were correlated with indices of mineralizable N. A multiple stepwise model using AA and N_ana as parameters provided the best predictor of corn N concentration (R = 0.86, p < 0.001). Another model using only LG provided the best predictor of corn N uptake (R = 0.78, p < 0.001). This results showed that sewage‐sludge and cow‐manure application is readily reflected in certain soil biological properties and that the biological tests may be useful in predicting N mineralization and availability in soil.     

Biochemical Characteristics of the Herb Mixture Prolipid as a Plant Food Supplement and Medicinal Remedy

Prolipid a known mixture of herbs is used as a plasma lipid lowering medicine. No side effects were registered. However, the bioactive substances of Prolipid were not investigated. Therefore in this investigation Prolipids bioactive compounds and antioxidant activity were studied. The contents of polyphenols and flavonoids were 19.87 ± 2.09 and 3.09 ± 0.31 mg gallic acid equivalent GAE/g DW and 2.09 ± 0.24 and 0.57 ± 0.05 mg catechin equivalent CE/g DW in water and methanol fractions, respectively. Anthocyanins (0.02 ± 0.001 mg/g DW) and flavanols (7.58 ± 0.81 μg CE/g DW) were found only in water fraction. The antioxidant activity of Prolipid, as determined by four different antioxidant assays [ferric-reducing/antioxidant power (FRAP); cupric reducing antioxidant capacity (CUPRAC); trolox equivalent antioxidant capacity (TEAC); 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH)], was higher in water than in methanol fraction. The correlation coefficients between polyphenols, flavonoids and antioxidant activities of Prolipid water extracts with TEAC were 0.97 and 0.90, respectively. It can be concluded that the content of polyphenol compounds in Prolipid is very high and they are the main contributors to Prolipids overall antioxidant activity. Prolipid is widely used in human treatment without known side effects on patients and is comparable to other medicinal plants, and as a strong antioxidant mixture could be used as a supplement to known atherosclerosis preventing diets.     

120份小麦品种(系)重要性状功能基因的KASP检测

为了解120份小麦品种(系)重要性状功能基因的组成,本研究利用高通量的KASP标记技术对株高、抗叶锈病、抗条锈病、抗赤霉病、抗穗发芽和加工品质等性状相关的基因进行了检测。结果表明,供试材料的株高基因组成包含5种类型,分别是Rht-B1a/Rht-D1a (1份)、Rht-B1a/Rht-D1b (58份)、Rht-B1a+160/Rht-D1a (2份)、Rht-B1a+160/Rht-D1b (30份)和Rht-D1a/Rht-B1b (29份)。在抗病性方面,有69份材料含抗叶锈病基因Lr14a,3份材料含Lr68基因;抗叶锈病基因Lr21和Lr34、抗赤霉病基因Fhb1、抗条锈病基因Yr15在供试材料中均未发现。在抗穗发芽方面,68份材料为TaMFT-A1基因的Jagger-type抗穗发芽单倍型,21份材料为TaMoc-A1基因的Hap-H抗穗发芽单倍型,22份材料为TaSdr-D1基因的TaSdr-D1a抗穗发芽单倍型,84份材料为TaPHS1基因的Rio Blanco type抗穗发芽单倍型。在品质方面,83份材料为非1B/1R易位系,20份材料含高分子量麦谷蛋白亚基5+10,供试材料均不含Bx7OE。上述结果表明,对常规育种手段育成的高代品系进行KASP标记辅助选择可作为一种重要的分子育种策略,能显著地提高小麦育种效率。