新疆罗布泊外围地区极端环境嗜碱放线菌生物学特性及活性物质筛选

2006～2007年从新疆罗布泊外嗣地区的泥土样品中分离了117株放线菌,初步筛选后对其中47株嗜碱放线菌进行了形态学鉴定,不同生长条件(pH值,盐NaCl、KCl、MgCl_2,碱性物质Na_2 CO_3、K_2CO_3、Mg_2CO_3、NaOH、KOH,温度)对菌株生长的影响,拮抗性、产酶活性检测及菌株LA4的分子进化鉴定等研究.结果发现,47株放线菌的15%属于诺卡氏菌属,70%属于链霉菌属,10%属于游动放线菌属,其中嗜碱链霉菌属占优势.在pH 7～11范围内,47株嗜碱放线菌均能生长.生长率为92%～95%.NaCl、KCl、MgCl,对嗜碱放线菌均具有抑制作用,NaCl、KCl的抑制作用高于MgCl_2,NaCl、KCl浓度超过10%时而MgCl_2 浓度超过15%时嗜碱放线菌完全停止生长.47株嗜碱放线菌对Na_2CO_3、K_2CO_3、MgCO_3、KOH、NaOH等碱性物质没有选择性,生长良好.47株嗜碱放线菌的最适生长温度为28～30℃.超过55℃后均不能生长.从47株嗜碱放线菌中筛选出了30株具有抗菌活性的菌株,其中对大肠杆菌有抑制作用的有11株,占36.7%,对金黄色葡萄球菌有抑制作用的有20株,占66.7%,对枯草杆菌有抑制作用的有16株,占53.3%;其中4株嗜碱放线菌LA4、LA24、LA33和LA19对3种指示菌均表现出抑制作用.在47株嗜碱放线菌中,74%具有淀粉酶活性,81%具有纤维素酶活性,43%具有蛋白酶活性,49%具有脂肪酶活性.通过分子鉴定,发现LA4为链霉菌中尚未报道的一个新亚种,其16S序列GenBank登录号为FJ182229.本研究结果表明新疆罗布泊外围地区存在大量的产纤维素酶、淀粉酶的嗜碱放线菌,并且潜藏着新的放线菌资源,为该地区嗜碱放线菌的种质资源开发和新药筛选有效菌源提供了参考.图5表4参20

Biological Characteristics and Active Substances of Alkalophilic Actinomycetes from Extreme Environment of Lop Nur Peripherals in Xinjiang, China

117 stains of actinomycetes were isolated from the soil and mud samples collected from the peripheral areas of the Lop Nur in Xinjiang in 2006 and 2007. Of them, 47 strains were alkalophilic actinomycetes. Their morphological characters were analyzed, and their growth features (pH; NaCl, KC1 and MgCl_2; alkaline substances Na_2CO_3, K_2CO_3, MgCO_3, NaOH and KOH; temperature), antagonistic actions and enzyme activities, as well as the molecular level of strain LA4 were studied. The results showed that 15% of the 47 strains were initially identified belonging to Nocardia, 70% to Streptomyces, 10% to Actinoplanes; and the 47 strains could grow at pH range of 7～11, and their growth rate ranging between 92% and 95%. NaCl, KC1 and MgCl_2 could inhibit the growth of all the alkalophilic actinomycetes. The inhibitory effect of NaCl and KC1 was higher than that of MgCl_2. When the concentrations of NaCl and KC1 exceeded 10%, and that of MgCl_2 exceeded 15%, the alkalophilic actinomycetes stopped growing. The alkalophilic actinomycetes could grow well on alkaline substances of Na_2CO_3, K_2CO_3, MgCO_3, NaOH and KOH, with no selection of them. Their optimal growth temperature was 28~30 ℃. When the temperature was over 55 ℃, the alkalophilic actinomycetes could not grow. Of them, 30 strains with antibacterial activity were selected, and 11 of them had antagonistic action on Escherichia coli, accounting for 36.7%, 20 of them on Staphylococcus aureus, for 66.8%, 16 of them on Bacillus subtilis, for 53.3% and 4 of them LA4, LA24, LA33 and LA19 on the three kinds of indicator bacteria. 74% of the 47 alkalophilic actinomycetes produced amylase, 81% produced cellulase, 43% produced protease and 49% produced lipase. Based on 16S sequence, LA4 was identified as a new subspecies of Streptomyces. The sequence of LA4 was obtained from the GenBank with its number of FJ18229. This study indicated that the peripheral area of Lop Nur was found with large number actinomycetes as new resources for producing amylase and cellulase. Fig 5, Tab 4, Ref 19