Comparison of plasma vitamin A and E,copper and zinc levels in free‐ranging and captive greater flamingos (Phoenicopterus roseus) and their relation to pododermatitis

Pododermatitis is a worldwide problem in captive flamingos. Studies in domestic poultry showed that nutrition is a possible influencing factor for pododermatitis. Vitamin A and E, copper and zinc levels were analysed in two different diets (diet 1 = in‐house mix and diet 2 = commercial diet) and in plasma of captive greater flamingos fed these diets and compared to those of free‐ranging greater flamingos. Results were analysed with respect to type and severity of foot lesions of the individuals from the different groups. Juvenile and subadult/adult captive flamingos on diet 1 showed various types and severities of foot lesions, whereas no foot lesions were found at the time of blood sampling in juvenile captive flamingos on diet 2. Juvenile captive flamingos on diet 1 had significantly lower plasma zinc levels than juvenile captive flamingos on diet 2 and juvenile free‐ranging flamingos; data were also lower than reference ranges for flamingos, poultry and cranes. There were no significant differences in plasma vitamin A, vitamin E, copper or zinc levels between animals with different types of foot lesions or with different severity scores. Shortly after the change to diet 2 (fed to juvenile captive flamingos that did not show any foot lesion), the flooring of the outdoor water pools was covered with fine granular sand. Because both factors (nutrition and flooring) were changed during the same evaluation period, it cannot be concluded which factor contributed in what extent to the reduction of foot lesions. While it is assumed that low plasma zinc levels identified in the group of juvenile captive flamingos on diet 1 were not directly responsible for foot lesions observed in these animals, they may have played a role in altering the skin integrity of the feet and predisposing them to pododermatitis.     

红曲霉SAGE文库中双标签的制备研究

研究探讨了红曲霉SAGE文库构建过程中总RNA提取、mRNA分离纯化、cDNA合成以及双标签 (Ditags)制备方法 ,并通过PCR条件的优化获得双标签PCR的最佳模板稀释浓度及扩增循环数。     

工厂化循环水产养殖废水处理研究进展

氨氮 (NH₄ ⁺-N)、硝态氮 (NO₃ ⁻-N)、亚硝态氮 (NO₂ ⁻-N) 等含氮 (N) 化合物是工厂化养殖系统中的主要污染物,水中N浓度较高易造成养殖水体污染并危害水生动物的安全,而好氧反硝化细菌被广泛用于养殖尾水的N降解。为获得一株能安全高效处理高NH₄ ⁺-N废水的菌株,对从养殖池塘筛得的耐高NH₄ ⁺-N好氧反硝化细菌WM28进行了研究。运用形态学观察、生理生化及16S rRNA基因测序对该菌株进行种属鉴定;采用抗生素实验、斑马鱼(Danio rerio) 攻毒实验对菌株进行了环境及生物安全性评估;在3种单一氮源模拟废水下测定其生长与脱氮性能,并在高浓度NH₄ ⁺-N模拟废水中对其进行脱氮能力测试。经鉴定,WM28为红球菌属赤红球菌 (Rhodococcus ruber);有较高的抗生素敏感性及较好的生物安全性。在单一NH₄ ⁺-N、NO₃ ⁻-N、NO₂ ⁻-N模拟废水中,培养48 h后N去除率分别为100%、76.3%、66.99%;高浓度NH₄ ⁺-N模拟废水结果显示：100~500 mg·L⁻¹高浓度NH₄ ⁺-N模拟废水在48 h后的NH₄ ⁺-N去除率为100%;700 mg·L⁻¹ NH₄ ⁺-N在116 h后的去除率在88%以上;在第120小时,NH₄ ⁺-N初始质量浓度为1 000 mg·L⁻¹时仍有脱氮能力,去除率为74.38%,说明菌株WM28具有较好的高NH₄ ⁺-N耐受性。综上所述,菌株WM28是一株耐NH₄ ⁺-N、安全且高效的好氧反硝化菌,在处理养殖尾水、工业废水上有较好的应用前景。

     

Changes in Biogenic Amines and Bacteria of Tiger-Toothed Croaker (Otolithes ruber) during Ice Storage

Changes in the content of biogenic amines (BA; e.g., putrescine, tyramine, and histamine) and the mesophilic and psychrotrophic bacterial counts of tiger-tooth croaker (Otolithes ruber) were monitored during ice storage for 18 days. BA and bacterial loads gradually increased (p < 0.05) with storage time. On the first day of storage, no amines were detected, and no histamine was detected up to 6 days. The best linear regressions between BA and bacterial counts were found between putrescine and psychrotrophic bacteria. Furthermore, it was found that psychrotrophs were the dominant microorganisms during storage and showed significant (p < 0.05) differences with storage time. The initial concentration of putrescine was 1.27 μg g^?1 and reached 18.8 μg g^?1 when the psychrotrophic bacterial load was over 10⁸ CFU g^?1. The results suggest that the level of putrescine is a suitable indicator of freshness for O. ruber, and the shelf life of O. ruber stored in ice as determined by BA content and microbiological data was 10 days.     

Rhodococcus ruber TCCC28001产丙烯腈水合酶过程调节及转化条件研究

对分离自土样中的产腈水合酶的菌株Rhodococcussp. TCCC28001进行16S rDNA序列测定及系统发育分析,可鉴定为Rhodococcus ruber.通过对其培养过程中pH的调控,尿素的加入时间的研究,使Rhodococcus ruber TCCC28001培养72 h后丙烯腈水合酶比活力达到4628 U/mL,比调控前提高了441%.考察了底物对腈水合酶活性及丙烯腈转化的影响,底物浓度≤20%对腈水合酶活性无抑制作用,丙烯腈转化率达100%,表明Rhodococcus ruber TCCC28001对底物有较强的耐受性.