Aspergillus niger 乳糖酶基因的克隆及序列分析

利用PCR及RT-PCR技术从黑曲霉(Aspergillus niger)菌株DL116中克隆到了乳糖酶基因组DNA，cDNA序列(GENBANK ACCESSION No.EF103141)。序列分析表明，乳糖酶基因组DNA序列长3368bp，其中含有8个内含子，cDNA编码区长2967bp，共编码988个氨基酸，氨基酸序列中共含有12个潜在的糖基化位点。并将此基因与不同来源的乳糖酶基因进行了同源性比较     

Growth Linkages and Urban Development in Niger

ABSTRACT. It is increasingly recognized that the assumption that the supply of tradable output is perfectly elastic, which underlies many regional economic models (esp. economic base models), does not hold in many developing countries. When the supply of tradable output (primarily agricultural products) and, in many cases, non-tradable output is inelastic, the resulting income multipliers will be substantially reduced. Recent calls for the promotion of market towns and smaller urban centers have not fully considered the impact of supply in elasticities on the capacity of such measures to stimulate broad-based development. This study uses data collected from firms in several market-town systems in Niger to examine the probable consequences. The paper argues that such policies are unlikely to be effective in countries like Niger where the vulnerability of the rural economy has severely limited the elasticity of the supply response, especially for agriculture and nonfarm production by small-scale producers.     

Inheritance of resistance to Striga gesnerioides biotypes from Mali and Niger in cowpea (Vigna unguiculata (L.) Walp.)

Pot and laboratory experiments were performed in order to elucidate the genetics of resistance of three cowpea (Vigna unguiculata (L.) Walp.) resistant sources to two biotypes of the parasitic weed Striga gesnerioides (Willd.) Vatke (witchweed). B301, Suvita-2 and IT82D-849 were crossed to susceptible cultivars. Roots of each plant of parental, F₁, F₂, BC₁ and BC₂ populations were washed free of soil and examined closely for S. gesnerioides attachment. Data on resistant and susceptible cowpea plants were analyzed using the chi-square test to ascertain the goodness of fit to different genetic ratios. Segregation patterns indicate monogenic dominant inheritance of resistance to both S. gesnerioides biotypes in B301. Suvita-2, which is susceptible to the biotype from Maradi, Niger, showed segregation patterns that indicate monogenic dominant inheritance of resistance to S. gesnerioides biotype from Cinzana, Mali. Results also indicate monogenic dominant inheritance of resistance to S. gesnerioides biotype from Cinzana in IT82D-849. However, the inheritance of resistance to the biotype from Maradi would be monogenic and recessive in this line. These results suggest that the resistance of all three sources would be easy to transfer to promising breeding lines. This revised version was published online in July 2006 with corrections to the Cover Date.     

Climate impacts on palm oil yields in the Nigerian Niger Delta

Palm oil production has increased in recent decades and is estimated to increase further globally. The optimal role of palm oil production, however, is controversial because of conflicts with other important land uses and ecosystem services. Local conditions and climate change affect resource competition and the desirability of palm oil production in the Niger Delta, Nigeria.The objectives of this study are to (1) establish a better understanding of the existing yield potentials of oil palm areas that could be used for integrated assessment models, (2) quantify for the first time uncertainties in yield potentials arising from the use of climate output data from different Global Circulation Models (GCM’s) with varied West African Monsoon (WAM) system representations forced to the same Regional Climate Models (RCM’s). We use the biophysical simulation model APSIM (Agricultural Production Systems Simulator) to simulate spatially variable impacts of climate change on oil palm yield over the Nigerian Niger Delta. Our results show that the impact of climate change on oil palm yield is considerable across our study region. The yield differences between the IPCC RCPs were small. The net impact of climate change on oil palm is positive and is dynamically inconsistent. There is no significant change in the simulated yield arising from the differences in the forcing’s data. We found the most effective strategy for oil palm yield optimization under climate change to be shifting of sowing dates and introduction of irrigation.     

Combined impacts of climate and nutrient fertilization on yields of pearl millet in Niger

Effects of climate variability and change on yields of pearl millet have frequently been evaluated but yield responses to combined changes in crop management and climate are not well understood. The objectives of this study were to determine the combined effects of nutrient fertilization management and climatic variability on yield of pearl millet in the Republic of Niger. Considered fertilization treatments refer to (i) no fertilization and the use of (ii) crop residues, (iii) mineral fertilizer and (iv) a combination of both. A crop simulation model (DSSAT 4.5) was evaluated by using data from field experiments reported in the literature and applied to estimate pearl millet yields for two historical periods and under projected climate change. Combination of crop residues and mineral fertilizer resulted in higher pearl millet yields compared to sole application of crop residues or fertilizer. Pearl millet yields showed a strong response to mean temperature under all fertilization practices except the combined treatment in which yields showed higher correlation to precipitation. The crop model reproduced reported yields well including the detected sensitivity of crop yields to mean temperature, but underestimated the response of yields to precipitation for the treatments in which crop residues were applied. The crop model simulated yield declines due to projected climate change by −11 to −62% depending on the scenario and time period. Future crop yields in the combined crop residues + fertilizer treatment were still larger than crop yields in the control treatment with baseline climate, underlining the importance of crop management for climate change adaptation. We conclude that nutrient fertilization and other crop yield limiting factors need to be considered when analyzing and assessing the impact of climate variability and change on crop yields.     

He-Ne激光辐照对黑曲霉A72的生物学效应

以黑曲霉为A72出发菌株,利用氦氖(He-Ne)激光对其单孢子悬液进行诱变育种,探讨激光辐照不同时间对黑曲霉孢子的存活率、菌重、酶活性等生理生化指标的影响.结果表明,不同辐照时间对生理生化指标产生不同的影响,确定激光的最佳辐照时间为6 min.     

米曲霉和黑曲霉双菌种制曲对豆酱酶系影响的研究

以黄豆和面粉为主要原料,以淀粉酶、蛋白酶、β-葡萄糖苷酶和纤维素酶的活性为指标,采用单因素试验方法,研究米曲霉和黑曲霉(质量比为1:1)对豆酱制曲酶系的影响,优化制曲工艺参数。试验结果表明,采用添加熟面粉的方式,制曲时间为36h,制曲温度为29～32℃,接种量0.04%,双菌种曲中酶的活性高于单一米曲霉曲。     

Peroxidase activity as a possible test for distinguishing s-plasm from n-plasm in sugar beet (Beta vulgaris L.)

Summary The O-type lines (N-plasm) of sugar beet (Beta vulgaris L.) proved to have a consistently lower peroxidase activity (49.2–62.7%) than their male sterile (MS) equivalents (S-plasm).Similar differences in peroxidase activity (45.4–56.3%) were found when O-type lines were compared with unrelated MS lines. They were also observed in different parts of the plant (cotyledons, hypocotyl + radicle, true leaves) and were reproducible.The fertile lines could be grouped by their level of peroxidase activity in categories of either S-plasm or N-plasm.The peroxidase activity test could be used for selection of N-plasm lines from fertile sugar beet populations and for selection of MS and O-type lines of higher stability.     

从先锋育种模式引发对我国玉米中试工作的思考

先玉335是铁岭先锋种子公司在中国土地上培育的玉米品种,于2004年通过国家审定,2009年的种植面积迅猛增加到133万hm2.杜邦先锋在中国的研发是自主进行的,铁岭先锋种子公司的两家合资公司只是在生产和商业销售上合作,不涉及育种研发和技术转让[1].     

黑曲霉产β-磷酸甘油酯酶固体发酵条件的研究

对一株高产β-磷酸甘油酯酶的黑曲霉进行最适培养方法和培养条件的研究。分别研究了底物浓度、氮源、培养基的含水量,以及培养基中的米糠和玉米粉的比例对黑曲霉产β-磷酸甘油酯酶的影响。实验结果表明,固体培养基中,用纱布覆盖培养基更适合黑曲霉产β-磷酸甘油酯酶的发酵,覆盖单层纱布的效果优于双层纱布。底物浓度在0.15%时,黑曲霉产酶活性最高。培养基中最佳米糠和玉米粉比例为6∶2。8g(干质量)培养基中的加水体积为21.5mL左右时,最利于黑曲霉产β-磷酸甘油酯酶的发酵。培养基中无机氮优于有机氮,且以硫酸氨最优。黑曲霉培养120h后再进行低温(4℃)处理72h的产酶活性最高。接种时搅拌和培养24h后的翻曲对黑曲霉产β-磷酸甘油酯酶都有促进作用,且接种时将菌种与培养基拌匀对产酶效率的提高比较明显。     

Flux of particulate inorganic matter through the Niger River into the Atlantic ocean

The solid load level in the Niger River proved to be subject to distinct seasonal variations, the highest concentration being attained well before peak river discharge.A total of 25.4×10⁹ kg of sediment was flushed into the Atlantic through the drainage system in 1980–1981, representing an upward review of a previous estimate statedin Martins (1982). The specific erosion rate then becomes 20.5·10³kg·km⁻²·y⁻¹, the highest so far measured in Africa.The composition of the transported sediment reflects the chemical disintegration of silicate rocks predominant in the basin.     

烤烟品种比较试验

以K326为对照，对引白巴西、美国和津巴布韦等国家和河南、安徽等省的13个种质资源材料进行生育期、农艺性状、经济性状、外观质量、化学成分和抗病性等方面的比较和分析。结果表明，现蕾期有2个品种比对照K326早7—8d，有2个晚6—10d；大田生育期有2个品种比K326早11d，2个晚7d，其余各生育期接近K326。13个品种中，分另q有6个和5个抗和中抗TMV；分另q有6个和4个抗和中抗黑胫病；分别有2个和7个抗和中抗南方根结线虫病。OX414产量最高，产值第二；津引1号产量第二，产值、上等烟比例、均价、级指和产指均为第一；筑波1号产量第三；宣洞区、W3．1．1、8022和小白筋产量和产值低于对照。OX414、津引1号等品种生育期与对照接近，外观质量较好，化学成分协调，抗病性较强，经济性状优于对照。     

2005—2007年辽宁省玉米区试品种抗病性分析

就2005-2007年辽宁省玉米区试参试品种对大斑病、弯孢菌叶斑病、灰斑病、茎腐病和丝黑穗病的抗病性情况进行了统计分析,结果表明,参试品种对弯孢菌叶斑病和茎腐病表现为中抗以上水平的数量逐年略有下降,对灰斑病和大斑病表现为抗性水平的品种数量逐年提高,对丝黑穗病表现为抗性水平的品种数量保持稳定.     

种子发芽试验存在的问题及对策

在种子的收购、调运、安全贮藏过程中和销售前,各种子企业通过发芽试验来测定种子批的最大发芽潜力。据此估测其田间播种价值．使栽培的优良品种获得优质、高产．避免不合格的种子用于生产所带来的损失。但在发芽试验中．由于环节较多、重复性强．检验者常常感到枯燥,机械性操作、生搬硬套、不注重细节,这样就会导致试验结果与实际情况产生偏差。给科研和生产造成不必要的损失和浪费。     

Influence of plant growth regulators on somatic embryogenesis in Niger (Guizotia abyssinica Cass.): an edible oilseed crop

Journal of Crop Science and Biotechnology - An improved protocol of direct somatic embryogenesis (SE) and shoot regeneration was developed, for the first-time, using leaf explants from in vitro...     

Elaboration and test of a decision rule for the application of mepiquat chloride on cotton in Mali

Farmers often make complex management decisions during a cropping cycle. To design new cropping systems that go beyond standard setups and are better adapted to local constraints, agronomists must formalize these farmer's decisions into decision rules that can be tested and disseminated. In Mali, there has been a marked decrease in cotton productivity over the last 10 years, whereas the area planted with cotton has doubled. However, cropping recommendations remain almost the same throughout the country. Cotton researchers have been asked to put forward new technical proposals suited to a wider range of socio-economic and biophysical cropping conditions.

The aim of this study was to develop a methodology to build a decision rule (DR) to help Malian farmers in making decisions on the use of growth regulators in cotton fields.

In the first phase, a 2-year experiment was conducted in two experimental stations, under a wide range of cotton vegetative growth conditions, along with different stand densities and fertilization rates. Mepiquat chloride (MC) was applied to half of the plots, and its effects were then computed against selected vegetative growth indicators measured before the date of MC application. A DR was proposed on this basis. In the second phase, the DR was tested in a six-village experiment. MC was applied in plots on 15 farms in each village and its effects on yield were recorded.

The results showed that is possible to build a DR for MC application based on LAI or aerial biomass indicators. The usual indicators, such as the five-node length technique, were not found to be useful. The response of cotton plots to MC for a given level of vegetative growth remained scattered, as other factors probably interfered, such as the length of the rainy season. Testing the DR in farmers’ fields showed that it was useful in determining appropriate MC applications. The usefulness of the DR is discussed on the basis of its accuracy and on the complexity of the selected indicator.     

一种测定杀菌剂对灰霉病菌(Botrytis cinerea)毒力方法的改进

通过在灰霉病菌（Botrytis cinerea）分生孢子悬浮液中加入1%酵母浸膏、2.5%葡萄糖和10%胡萝卜汁,接种离体黄瓜子叶,病叶率及发病均匀度较高,确立了一种重复性好、操作简便的测定杀菌剂对灰霉病菌毒力的新方法-黄瓜子叶喷雾法。以该方法、菌丝生长速率法和孢子萌发法分别测定比较了戊唑醇、代森锰锌和异菌脲对灰霉病菌的毒力,发现药剂浓度的对数值与其抑制率的几率值之间有很高的相关性,相关系数均大于0.95。该方法可用于灰霉病菌抗药性监测和杀菌剂敏感性测定。     

Development of a seedling screening test for predicting relative grain protein content in oats

Summary Growth room experiments were conducted to study associations of grain protein content with properties of seedling leaf sections of oats (Avena sativa L.) using (1) 10 cultivars differing genetically in grain % protein, and (2) 10 populations of a single high protien cultivar (Hinoat) differing phenotypically in grain % protein. These populations, which were derived from a nitrogen fertilizer experiment, had grain protein concentrations which varied over the whole range displayed by the high and low protein cultivars when the latter were tested in a conventional field trial.Seedling leaf % protein was closely associated with grain % protein in both (1) and (2). Chlorophyll content per unit leaf area and leaf dry weight per unit leaf area were significantly higher in the high than in the low protein cultivars, and were significantly higher in all the Hinoat populations than in the low protein cultivars.Excised seedling leaf sections were placed on filter paper moistened with 1 ppm kinetin solution and kept in the dark at 25°C. After 96 h chlorophyll content per unit leaf area was again significantly higher in the high protein cultivars and in all the Hinoat populations than in the low protein cultivars, and the consequent differences in leaf colour were then readily visible. Absolute amounts of chlorophyll lost per unit leaf area were similar in all cultivars and populations, but the low protein cultivars showed a greater proportional loss (as % of initial content). A colour scale was used to visually rate the senesced leaf sections. The visual rating allowed the rapid separation of the high and low protein cultivars, and there was no significant variation in the ratings of the Hinoat populations.It is suggested that this procedure may be useful in the early selection phases of protein breeding programs for screening large populations rapidly at the seedling stage to detect genetic differences in potential grain protein content.Contribution No. 438 from Ottawa Research Station.