紫花苜蓿多叶型与三叶型品种同工酶的比较研究

采用聚丙烯酰胺凝胶电泳技术,对国外2种多叶型苜蓿及国内外5种三叶型苜蓿幼苗的5种同工酶进行了测定,将酶谱数量化,应用SPSS统计软件求出各品种间的遗传一致度及欧氏遗传距离,并进行了聚类分析.结果表明:1)测定的5种同工酶中过氧化物酶(PER)、酯酶(EST)、淀粉酶(AMY)具有多态性,综合此3种酶酶谱可以鉴定供试的7个品种;2)2个多叶型品种具有一共同特征酶带PER-4,国内品种的过氧化物酶活性明显高于国外品种;3)品种间的遗传一致度为0.826～0.952,欧氏遗传距离为0.500～1.118,多叶型品种间遗传一致度为0.904,欧氏遗传距离为0.500;4)等级聚类分析结果为,以欧氏遗传距离0.400为分界,供试品种分为3类,2个多叶型品种为一类,其余的5种三叶型品种分为另两类.     

Changes in the bacterial community and composition of fermentation products during ensiling of wilted Italian ryegrass and wilted guinea grass silages

To gain further insights into temperate and tropical grass ensiling, fermentation products and bacterial communities were examined at both the initial and late stages of ensiling of wilted Italian ryegrass and wilted guinea grass silages. 2,3‐Butanediol and ethanol fermentation were observed in wilted Italian ryegrass silage. Enterobacteria such as Rahnella sp. and Enterobacter sp. may have been involved in fermentation; however, alcohol production was intensified after the silage enterobacterial community overwhelmed the pre‐ensiled enterobacterial community. Pediococcus spp. appeared in silage stored for 4 months, when a significant increase in lactic acid content was seen compared with that at 2 months. Prolonged storage enhanced acetic acid fermentation in wilted guinea grass silage. The disappearance of Enterococcus sulfureus and appearance of Lactobacillus plantarum may have been associated with the increased acetic acid content. Although many species of enterobacteria were found in common between the pre‐ensiled crop and silages of Italian ryegrass and guinea grass, marked differences were seen in the type of fermentation from the initial stages. These results indicate that the bacterial community of pre‐ensiled crops may be immediately replaced by one that is adapted to ensiling environments, although metabolic changes may continue over the course of ensiling.     

Susceptibility to Coolness at the Young Microspore Stage under High Nitrogen Supply in Rice (Oryza Sativa L.). Proteome Analysis of Mature Anthers

Abstract

In vitro pollen germination experiment using agar plates showed that the growth under high nitrogen conditions enhanced the damage to pollen germination ability caused by the cooling at the young microspore stage. To clarify the physiological factors related to this damage to pollen germination, we performed the comparative proteome analysis of mature anthers and identified proteins that were changed by high nitrogen conditions or high nitrogen plus cooling conditions. Proteins were extracted from mature anther samples and separated by two-dimensional polyacrylamide gel electrophoresis. By comparing anther protein maps of the samples collected from the plants grown under standard nitrogen conditions, high nitrogen conditions and high nitrogen plus cooling conditions, we found 11 protein spots, which varied with the treatment. These protein spots were identified based on the rice proteome database and/or peptide mass fingerprinting (PMF) analysis after digestion with trypsin. Digested samples were analyzed by matrix-assisted laser desorption/ionization-time flight mass spectrometry to produce PMF data. Database searches using these PMF data revealed the identities of 9 proteins. Seven of these proteins were polypeptides involved in cell elongation, stress responses and sugar metabolism. The relation between the fluctuations of these proteins and the decrease in pollen germination are discussed.     

Microbial composition and diversity of an upland red soil under long-term fertilization treatments as revealed by culture-dependent and culture-independent approaches

Background, aim, and scope  Fertilization is an important agricultural practice for increasing crop yields. In order to maintain the soil sustainability, it is important to monitor the effects of fertilizer applications on the shifts of soil microorganisms, which control the cycling of many nutrients in the soil. Here, culture-dependent and culture-independent approaches were used to analyze the soil bacterial and fungal quantities and community structure under seven fertilization treatments, including Control, Manure, Return (harvested peanut straw was returned to the plot), and chemical fertilizers of NPK, NP, NK, and PK. The objective of this study was to examine the effects on soil microbial composition and diversity of long-term organic and chemical fertilizer regimes in a Chinese upland red soil. Materials and methods  Soil samples were collected from a long-term experiment station at Yingtan (28°15′N, 116°55′E), Jiangxi Province of China. The soil samples (0–20 cm) from four individual plots per treatment were collected. The total numbers of culturable bacteria and fungi were determined as colony forming units (CFUs) and selected colonies were identified on agar plates by dilution plate methods. Moreover, soil DNAs were extracted and bacterial 16S rRNA genes and fungal 18S rRNA genes were polymerase chain reaction amplified, and then analyzed by denaturing gradient gel electrophoresis (DGGE), cloning, and sequencing. Results  The organic fertilizers, especially manure, induced the least culturable bacterial CFUs, but the highest bacterial diversity ascertained by DGGE banding patterns. Chemical fertilizers, on the other hand, had less effect on the bacterial composition and diversity, with the NK treatment having the lowest CFUs. For the fungal community, the manure treatment had the largest CFUs but much fewer DGGE bands, also with the NK treatment having the lowest CFUs. The conventional identification of representative bacterial and fungal genera showed that long-term fertilization treatments resulted in differences in soil microbial composition and diversity. In particular, 42.4% of the identified bacterial isolates were classified into members of Arthrobacter. For fungi, Aspergillus, Penicillium, and Mucor were the most prevalent three genera, which accounted for 46.6% of the total identified fungi. The long-term fertilization treatments resulted in different bacterial and fungal compositions ascertained by the culture-dependent and also the culture-independent approaches. Discussion  It was evident that more representative fungal genera appeared in organic treatments than other treatments, indicating that culturable fungi were more sensitive to organic than to chemical fertilizers. A very notable finding was that fungal CFUs appeared maximal in organic manure treatments. This was quite different from the bacterial CFUs in the manure, indicating that bacteria and fungi responded differently to the fertilization. Similar to bacteria, the minimum fungal CFUs were also observed in the NK treatment. This result provided evidence that phosphorus could be a key factor for microorganisms in the soil. Thus, despite the fact that culture-dependent techniques are not ideal for studies of the composition of natural microbial communities when used alone, they provide one of the more useful means of understanding the growth habit, development, and potential function of microorganisms from soil habitats. A combination of culture-dependent and culture-independent approaches is likely to reveal more complete information regarding the composition of soil microbial communities. Conclusions  Long-term fertilization had great effects on the soil bacterial and fungal communities. Organic fertilizer applications induced the least culturable bacterial CFUs but the highest bacterial diversity, while chemical fertilizer applications had less impact on soil bacterial community. The largest fungal CFUs were obtained, but much lower diversity was detected in the manure treatment. The lowest bacterial and also fungal CFUs were observed in the NK treatment. The long-term fertilization treatments resulted in different bacterial and fungal compositions ascertained by the culture-dependent and also the culture-independent approaches. Phosphorus fertilizer could be considered as a key factor to control the microbial CFUs and diversity in this Chinese upland red soil. Recommendations and perspectives  Soil fungi seem to be a more sensitive indicator of soil fertility than soil bacteria. Since the major limitation of molecular methods in soil microbial studies is the lack of discrimination between the living and dead, or active and dormant microorganisms, both culture-dependent and culture-independent methods should be used to appropriately characterize soil microbial diversity.     

Eukaryotic communities associated with the decomposition of rice straw compost in a Japanese rice paddy field estimated by DGGE analysis

To estimate the succession and phylogenetic composition of the eukaryotic communities responsible for the decomposition of rice straw compost under flooded conditions during the cultivation period of paddy rice, denaturing gradient gel electrophoresis (DGGE) analysis targeting 18S rDNA followed by sequencing was conducted in a Japanese paddy field. The eukaryotic communities in rice straw compost incorporated into the flooded paddy field were influenced by the mid-season drainage and mainly composed of fungi (Ascomycota, Zygomycota, and Chytridiomycota) and protozoa (Ciliophora, Euglyphida, and Dactylopodida), most of which existed continuously during the cultivation period of paddy rice. The results indicated that these eukaryotic members were associated with the decomposition of rice straw compost in paddy field soil directly or indirectly.     

高凝胶性蛋白粉制取工艺条件优化

为了进一步改善高凝胶蛋白粉的品质,探讨了利用酶交联反应制取高凝胶蛋白粉的新方法,在进行了琥珀酰化酪蛋白添加量、反应pH值、转谷氨酰胺酶添加量对蛋白粉凝胶强度影响的单因素试验基础上,该文通过响应面分析法对制取高凝胶性蛋白粉的酶交联反应条件进行了优化,并通过SDS-PAGE电泳、扫描电镜等手段探讨了酶交联蛋白粉凝胶性能增加的机理。结果表明,最佳工艺条件为:琥珀酰化酪蛋白添加量2.29%、反应pH值5.87、转谷氨酰胺酶添加量1.06%、反应温度40℃、反应时间40min。理论最大凝胶值为1072.8g/cm2,验证值为1054.5g/cm2,说明预测模型可靠性高,可用于反应条件的优化。     

木聚糖酶对肉仔鸡后肠道微生物的影响

主要研究了小麦基础口粮添加木聚糖酶对肉仔鸡后肠道微生物的影响.将120只7日龄肉仔鸡分成2组,日粮分别添加0,0.1%木聚糖酶,饲喂至21日龄,研究木聚糖酶对肉仔鸡后肠道菌群数量变化的影响.结果表明,加酶未使同肠和盲肠乳酸杆菌、双歧杆菌和大肠杆菌数量发生显著变化.利用变性梯度凝胶电泳技术研究了木聚糖酶对肉仔鸡后肠细菌群体的影响.结果表明,加酶组回肠和盲肠的图谱比对照组条带相对较多,但差异不显著;组内个体间的图谱相似性比组问的相似性相对较大.木聚糖酶影响肉仔鸡后肠微生物数量和种群的作用效果不明显.     

DGGE技术在瘤胃微生物多态性研究中的应用

利用传统的方法很难鉴别瘤胃微生物的差异,变性梯度凝胶电泳（DGGE）技术就很好地解决了该问题。DGGE是一种新型的用于检测核酸变异和点突变的电泳方法,具有可靠性强、重现性高、方便快捷等优点,可应用于瘤胃微生物群落多样性和动态性分析。     

Rapid detection of <Emphasis Type="Italic">Peste des Petits Ruminants</Emphasis> (PPR) virus antigen in Sudan by agar gel precipitation (AGPT) and haemagglutination (HA) Tests

AGPT and HA tests were employed for rapid diagnosis of PPRV infection in sheep and goats in Sudan. Forty lymph nodes and spleen samples from suspected cases of PPR in both sheep and goats were examined by AGPT and HA tests for detection of PPRV antigen. Viral antigen was detected from (77.5%) of the samples tested by AGPT and (92.5%) tested by HA test. The results of both tests revealed that HA test was more sensitive than AGPT for detection of PPRV antigen (Kappa statistics 0.4366). Another advantage of the HA test over AGPT was that it can differentiate PPRV from RPV. Thus the HA test represents a quick, easy, simple, cheap and reliable confirmatory test for the diagnosis of PPR and differential diagnosis of PPRV and RPV. The HA test was carried out using chicken, goat and pig RBCs. Chicken RBCs were found to be the most sensitive for detection of PPRV antigen, followed by goat then pig RBCs. The HA time when using chicken RBCs was 20–25 minutes, using goat RBCs was 25–30 minutes and using pig RBCs was 40–45 minutes. The distribution of PPR infection in four different regions of Sudan was investigated.