溶藻细菌DC21的分离、鉴定及其溶藻特性

从云南滇池中分离得到一株溶藻细菌DC21,经鉴定为葡萄球菌属的1种(Staphylococcussp.),可溶解铜绿微囊等9种藻.试验表明,经过滤、离心沉降及高温灭菌处理的滤液,均能强烈抑制铜绿微囊藻的生长,说明其溶藻作用的因子之一为该菌的胞外分泌物,且这种物质具有热稳定性.细菌DC21使藻的光合作用受到抑制;在试验的第1d,受试藻的超氧物歧化酶及过氧化氢酶活性显著增高,但在第7d,这两种抗氧化保护酶的活性显著下降;受试藻的丙二醛含量明显增高,说明该菌促使其发生了膜脂过氧化.     

Microbiological evaluation of 4-(6-chloro-7H-purin-8-ylamino)-3-nitro-chromen-2-one with a comparison to antibacterial activity of standard drugs

Nucleophilic substitution of 4-chloro-3-nitro-2-oxo-2H-chromen-2-one 3 by 6-chloro-7H-purin-2-ylamine (a), yielded the corresponding 4-(6-chloro-7H-purin-8-ylamino)-3-nitro-chromen-2-one 4. The chemical structure of synthesized compound was characterized using IR and NMR spectra, and elemental analyses. The purified synthesized compound 4 was tested at concentrations 1, 3, 5 mg/ml for its antibacterial activity against three bacterial cultures: Staphylococcus aureus, Escherichia coli, and Bacillus cereus. The antibacterial activity of synthesized compound was compared to antibacterial activity of standard antibiotics cephalexine and streptomycin.     

诺氟沙星降解菌NOR-36的分离筛选及降解特性研究

利用微生物分离筛选技术从医药厂废水池活性污泥中分离得到一株可以以哌嗪为一级基质共代谢降解诺氟沙星的菌株.经生理生化鉴定和16S rDNA基因序列同源性分析,将此菌株初步鉴定为山羊葡萄球菌(Staphylococcus caprae),命名为NOR-36.当菌株NOR-36在温度为30℃、pH 7.0、诺氟沙星起始浓度为5 mg·L~(-1),哌嗪与诺氟沙星浓度比为5∶1时培养10 d降解率可达92.6%.而在相同的实验条件下,不加一级基质的空白实验中诺氟沙星的降解率最高仅为8.5%.可知菌株NOR-36以哌嗪为一级基质对诺氟沙星进行共代谢生物降解,其对诺氟沙星的降解率显著提高.采用高效液相色谱-质谱联用仪分析确定菌株降解诺氟沙星的过程中产生3种主要的中间代谢产物,分子式分别为:C_(16)H_(18)FN_3O_4(产物1)、C_(14)H_(16)FN_3O_3(产物2)、C_(12)H_(11)FN_2O_3(产物3).分析中间产物结构可知:NOR-36首先在共代谢关键酶作用下使诺氟沙星哌嗪环上碳氮键断裂,并且中间位置碳原子被氧原子氧化,加氧形成羰基,得到产物1;之后产物1继续被氧化,碳氮键继续断裂,—COCH_3基团被去除生成产物2,最后产物2经氧化后,—CH_2CH_2NH_2基团被去除,最终得到产物3.     

Urban stormwater disinfection, quality variability during storage and influence on the freshwater algae: Implications for reuse safety

Stormwater reuse is one of the most important ways to mitigate water resource shortage. However, urban stormwater contains many bacteria species, which threaten the reuse safety. Therefore, stormwater disinfection is highly needed. Although disinfection has been widely conducted in the drinking water and reclaimed water, it is rarely carried out for stormwater. This study collected the roof stormwater and undertook chlorination disinfection. Two typical bacteria, Escherichia coli (E. coli) and Staphylococcus aureus (S.aureus) were selected in this study to investigate the disinfection efficiency. It is found that bacteria species present in the stormwater had an important influence on disinfection efficiency while the original stormwater quality did not show an obvious affect. However, when the disinfected stormwater was stored, the stormwater quality was highly variable during its storage process and the variability was affected by bacteria species. The S.aureus containing stormwater showed a high variability of quality and S.aureus significantly regrew. However, the E.coli containing stormwater quality had a relatively low variability and E.coli did not significantly regrew. Additionally, it is noted that after storage, the dissolved form of stormwater was more positive to the freshwater algae's growth while the particulate form (including bacteria and other particulate matters) was less. This implies that a further treatment such as filtration is needed before the stored stormwater is recharged into receiving waters in order to remove particulate forms. These research outcomes can provide useful insight to effective stormwater disinfection and ensure reuse safety.