应用性外激素监测马尾松毛虫发生数量的初步研究

本研究采用持效期达 3 0天以上的复合橡胶载体的新型诱芯诱捕器对马尾松毛虫进行林间监测 ,发现诱蛾数量与田间调查的幼虫数量有很大的关联性 ,各乡镇每诱捕点平均诱蛾数与 1代、2代幼虫虫株率、平均虫口的变化趋势基本相同     

Adverse wind conditions during northward Sahara crossings increase the in‐flight mortality of Black‐tailed Godwits

Long‐distance migratory flights are predicted to be associated with higher mortality rates when individuals encounter adverse weather conditions. However, directly connecting environmental conditions experienced in‐flight with the survival of migrants has proven difficult. We studied how the in‐flight mortality of 53 satellite‐tagged Black‐tailed Godwits (Limosa limosa limosa) during 132 crossings of the Sahara Desert, a major geographical barrier along their migration route between The Netherlands and sub‐Saharan Africa, is correlated with the experienced wind conditions and departure date during both southward and northward migration. We show that godwits experienced higher wind assistance during southward crossings, which seems to reflect local prevailing trade winds. Critically, we found that fatal northward crossings (15 deaths during 61 crossings) were associated with adverse wind conditions. Wind conditions during migration can thus directly influence vital rates. Changing wind conditions associated with global change may thus profoundly influence the costs of long‐distance migration in the future.     

河北省南大港农场2002年夏蝗发生特点及原因浅析

进入 90年代以来 ,南大港蝗区东亚飞蝗Locustamigratoriamanilensis(Meyen)大发生 6次 ,2 0 0 1年夏秋蝗发生面积达 2 6万hm2 ,5龄蝗蝻最高密度为 1 0 0 0 0头 m2 。 2 0 0 2年形势更为严峻 ,仅夏蝗发生面积超过 2万hm2 ;分别造成 1 3 0 0hm2 和 2 70 0hm2 的芦苇被吃成光杆和被啃食的严重破叶。出土时间早、孵化时间长、龄期悬殊大是今年夏蝗发生的主要特点。主要原因是去年越冬卵块基数大 ,其次是受气候条件和农业环境的影响     

白魔芋和花魔芋葡甘露聚糖研究

从白魔芋和花魔芋的块茎中分离纯化出两种魔芋葡甘露聚糖(Konjac Glucomannan,简称KGM),分别名为白魔芋葡甘露聚糖(aKGM)和花魔芋葡甘露聚糖(rKGM)。通过超离心、玻璃纤维纸电泳和凝胶过沪证明aKGM和rKGM都是均一的多糖。这两种多糖都由甘露糖(M)和葡萄糖(G)组成,其克分子比G/M:aKGM为1:1.69,rKGM为1:1.60,分子量前者为8.09×10~5,后者为7.37×10~5。酶水解实验和红外光谱分析说明aKGM和rKGM都是由甘露糖和葡萄糖以β-1,4-糖苷键连接的杂多糖;有O-乙酰基的特征吸收峰,说明在某些糖残基上可能有乙酰基团。     

Response of Litter Decomposition to Simulated N Deposition in Disturbed, Rehabilitated and Mature Forests in Subtropical China

The response of decomposition of litter for the dominant tree species in disturbed (pine), rehabilitated (pine and broadleaf mixed) and mature (monsoon evergreen broadleaf) forests in subtropical China to simulated N deposition was studied to address the following hypothesis: (1) litter decomposition is faster in mature forest (high soil N availability) than in rehabilitated/disturbed forests (low soil N availability); (2) litter decomposition is stimulated by N addition in rehabilitated and disturbed forests due to their low soil N availability; (3) N addition has little effect on litter decomposition in mature forest due to its high soil N availability. The litterbag method (a total of 2880 litterbags) and N treatments: Control-no N addition, Low-N: −5 g N m⁻² y⁻¹, Medium-N: −10 g N m⁻² y⁻¹, and High-N: −15 g N m⁻² y⁻¹, were employed to evaluate decomposition_. Results indicated that mature forest, which has likely been N saturated due to both long-term high N deposition in the region and the age of the ecosystem, had the highest litter decomposition rate, and exhibited no significant positive and even some negative response to nitrogen additions. However, both disturbed and rehabilitated forests, which are still N limited due to previous land use history, exhibited slower litter decomposition rates with significant positive effects from nitrogen additions. These results suggest that litter decomposition and its responses to N addition in subtropical forests of China vary depending on the nitrogen status of the ecosystem.     

Development of a 16S rRNA gene-based prototype microarray for the detection of selected actinomycetes genera

Actinomycetes are known for their secondary metabolites, which have been successfully used as drugs in human and veterinary medicines. However, information on the distribution of this group of Gram-positive bacteria in diverse ecosystems and a comprehension of their activities in ecosystem processes are still scarce. We have developed a 16S rRNA-based taxonomic microarray that targets key actinomycetes at the genus level. In total, 113 actinomycete 16S rRNA probes, corresponding to 55 of the 202 described genera, were designed. The microarray accuracy was evaluated by comparing signal intensities with probe/target-weighted mismatch values and the Gibbs energy of the probe/target duplex formation by hybridizing 17 non-actinomycete and 29 actinomycete strains/clones with the probe set. The validation proved that the probe set was specific, with only 1.3% of false results. The incomplete coverage of actinomycetes by a genus-specific probe was caused by the limited number of 16S rRNA gene sequences in databases or insufficient 16S rRNA gene polymorphism. The microarray enabled discrimination between actinomycete communities from three forest soil samples collected at one site. Cloning and sequencing of 16S rRNA genes from one of the soil samples confirmed the microarray results. We propose that this newly constructed microarray will be a valuable tool for genus-level comparisons of actinomycete communities in various ecological conditions.     

里氏木霉液体发酵产纤维素酶的研究

在摇瓶试验基础上,采用里氏木霉(Trichoderma reesei)HC-415菌株进行5L自控罐产纤维素酶深层发酵试验。在通气量为 0.2—0.6vvm、搅拌速度为 400r/min、发酵液pH控制在5.8—6.1的条件下,发酵液的羧甲基纤维素(CMC)酶酶活最高为325.0mg糖/ml,滤纸糖酶(FPA)酶活最高达17.9mg糖/ml。发酵周期为108h。所得冻干纤维素酶粉CMC酶活最高3111IU/g,FPA最高135IU/g ,对发酵液得率平均6.7g/L。酶活总收率CMC酶活平均78.2％,FPA酶活平均73.5％。     

Using pseudo-amino acid composition and support vector machine to predict protein structural class

As a result of genome and other sequencing projects, the gap between the number of known protein sequences and the number of known protein structural classes is widening rapidly. In order to narrow this gap, it is vitally important to develop a computational prediction method for fast and accurately determining the protein structural class. In this paper, a novel predictor is developed for predicting protein structural class. It is featured by employing a support vector machine learning system and using a different pseudo-amino acid composition (PseAA), which was introduced to, to some extent, take into account the sequence-order effects to represent protein samples. As a demonstration, the jackknife cross-validation test was performed on a working dataset that contains 204 non-homologous proteins. The predicted results are very encouraging, indicating that the current predictor featured with the PseAA may play an important complementary role to the elegant covariant discriminant predictor and other existing algorithms.