Breakdown of azadirachtin A in a tropical soil amended with neem leaves and animal manures

A field investigation was conducted to assess the breakdown of azadirachtin A in a tropical coastal savanna soil amended with neem leaves （NL） combined with poultry manure （PM） or cow dung （CD） using gas chromatography. Samples in polythene bags 15 cm long and 4.8 cm in diameter were randomly placed to a depth of 14 cm in the soil, and azadirachtin A concentration was assessed on days 0, 14, 28, 42, 56, 70, and 84. Azadirachtin A degradation in the soil followed first-order reaction kinetics with different half-lives obtained for varying combinations of the amendments. Higher neem amendment levels of 100 g gave shorter half-lives of azadirachtin A than the lower levels of 50 g. Within the 50 g NL group the additions of the poultry manure and the cow dung gave significantly shorter （P 〈0.05） half-lives of azadirachtin A than the sole neem amendment, whereas in the 100 g NL group only additions of 10 g CD and 10 g PM were significantly less （P 〈 0.05） than the sole neem amendment. Different changes resulting from the kind and quantity of animal manure added were observed in the half-lives of azadirachtin A. The 100 g NL group had significantly higher （P 〈0.05） moisture content, which, coupled with the likely differeaces in microbial biomass, could be the major factor responsible for variations in the half-llfe of the compound. Therefore, the quantity of the neem leaves applied and the addition of animal manure affected the breakdown of azadirachtin A in the soil amended with neem leaves.     

The unexpected discovery of <Emphasis Type="Italic">Brucella abortus</Emphasis> Buck 19 vaccine in goats from Ecuador underlines the importance of biosecurity measures

Very few, mostly old, and only preliminary serological studies of brucellosis in goats exist in Ecuador. In order to assess the current epidemiological situation, we performed a cross-sectional serological study in the goat populations of Carchi (n?=?160 animals), Pichincha (n?=?224 animals), and Loja provinces (n?=?2024 animals). Only two positive serological results (RB negative and SAT-EDTA ≥400 IU/ml) were obtained in lactating goats from the same farm in Quito (Pichincha province). Additionally, milk was sampled from 220 animals in Pichincha province. The present study indicates a low apparent prevalence in Pichincha province and absence in Carchi and Loja provinces. A total of 25 positive milk ring tests (MRT) were obtained in Pichincha province yielding a prevalence of MRT of 11.16%. Subsequent culture was performed on the positive MRT samples. All results were negative, apart from a single sample, obtained from a serologically positive goat in Quito, that was positive for Brucella abortus strain 19 (B19). Several hypotheses are forwarded concerning this unexpected result. The most likely hypothesis is the possible accidental use of a needle, previously used for vaccination of cattle with the said vaccine, for the administration of drug treatment to the goat. This hypothesis underlines the necessity of biosecurity measures to prevent this type of accidents.     

宠物鸟H3N8亚型流感病毒HA基因的特征性分析

来自香港和世界各地的10株宠物鸟H3N8流感病毒的HA基因进行了全基因序列测定,用DNASTAR和Tree-View软件进行序列编辑,序列翻译,进化树绘制和分子演化分析.结果表明来自不同国家和地区的H3N8流感病毒的HA基因都非常相似,都形成一个独立的分支,属于欧亚亚系,同源率为95.9%～100%;香港2001年宠物鸟的毒株之间的同源率最高,分别为99.2%～100%.HA基因与A/Equine/Jilin/89(H3N8)的同源性为最高,在92.9%～93.6%之间.氨基酸分析表明只有A/Parakeet/Netherland/33/01的HA基因在97～99受体结合位点处有一个额外潜在的糖基化位点NKT;因此可见宠物鸟H3N8流感病毒的HA基因高度保守,HA基因均来自共同的祖先.     

细胞壁降解酶在球刺盘孢侵染过程中的作用

为明确球刺盘孢Colletotrichum coccodes产生的细胞壁降解酶(CWDEs)在其侵染马铃薯过程中的作用, 本文对球刺盘孢离体和活体条件下产生的CWDEs种类及活性进行检测, 并通过RT-qPCR测定了球刺盘孢侵染过程中多聚半乳糖醛酸酶(PG)基因的表达情况。通过定性测定发现, 球刺盘孢能够产生果胶酶、纤维素酶和蛋白酶; 定量测定发现, 球刺盘孢可产生羧甲基纤维素酶(Cx)、β-葡萄糖苷酶(β-Glu)、PG和聚甲基半乳糖醛酸酶(PMG)。在活体条件下, 球刺盘孢可在马铃薯茎秆内产生PG、PMG和多聚半乳糖醛酸反式消除酶(PGTE), 且酶活分别于接种后48、72 h和144 h达到最大值, 分别为26.50、77.61 U/mL和0.16 U/mg。分别将羧甲基纤维素钠和果胶诱导后的酶液接种至马铃薯茎秆可引起植物组织浸腐, 与球刺盘孢引起的典型症状相似。除此之外, 球刺盘孢的4个PGs基因均在其侵染后24 h和48 h显著共上调表达。综上所述, 该研究结果表明, 果胶酶在球刺盘孢致病过程中发挥重要作用。     

Genetic diversity of Forest and Savannah chicken populations of Ghana as estimated by microsatellite markers

The characterization of indigenous animal genetic resources is a requisite step in providing needed information for the conservation of useful genotypes against future needs. Thus, in this study, 22 microsatellite markers were used to genotype 114 local chickens from the Forest (n = 59) and Savannah (n = 55) eco‐zones of Ghana and the results compared to those of the ancestral red junglefowl (n = 15) and two European commercial chicken populations – a broiler (n = 25) and white leghorn (n = 25). A total of 171 alleles were observed, with an average of 7.8 alleles per locus. The local Ghanaian chickens showed higher diversity in terms of the observed number of alleles per locus (6.6) and observed heterozygosity (0.568) compared with the combined control populations (6.0 and 0.458, respectively). However, Wright's F‐statistics revealed negligible genetic differentiation (F_ST) in local Ghanaian chicken populations. In addition, 65% of the Savannah chickens were inferred to be more likely from the Forest, suggesting a south‐north dispersal of chickens from their probable original location in the Forest zone to the Savannah areas. It is concluded that the Forest and Savannah chickens of Ghana are a single, randomly mating unselected population, characterized by high genetic diversity and constitute a valuable resource for conservation and improvement.