First report of the blaVIM gene in environmental isolates of Buttiauxella sp.

Several works have demonstrated the presence of metallo‐β‐lactamases (MBLs) in clinical bacteria. However, in environmental isolates, few works have reported on these enzymes. In this study, we report for the first time two environmental isolates of Buttiauxella sp. recovered from chrysanthemum plantations in Brazil containing bla_VIM gene and producing MBLs.     

Identification of a functional dddD-Rh for dimethyl sulfide production in the Antarctic Rhodococcus sp. NJ-530

Dimethylsulfoniopropionate (DMSP) is widespread in the oceans, and its biological metabolite, dimethyl sulfide (DMS), plays an important role in the atmosphere. The Antarctic region has become a hotspot in DMS studies due to the high spatial and temporal variability in DMS(P) concentration, but the level of bacterial DMS production remains unclear. In this study, a bacterium isolated from Antarctic floating ice, Rhodococcus sp. NJ-530, was found to metabolize DMSP into DMS, and the rate of DMS production was measured as 3.96 pmol·mg protein⁻¹·h⁻¹. Rhodococcus sp. NJ-530 had a DddD-Rh enzyme containing two CaiB domains, which belonged to the CoA-transferase III superfamily. However, the DddD-Rh had a molecular weight of 73.21 kDa, which was very different from previously characterized DddD enzymes in sequence and evolution. In vitro assays showed that DddD-Rh was functional in the presence of acetyl-CoA. This was the first functional DddD from Gram-positive Actinobacteria. Moreover, a quantitative real-time polymerase chain reaction revealed that high temperature facilitated the expression of dddD-Rh, and changes of salinity had little effect on it. This study adds new evidence to the bacterial DMS production in the Southern Ocean and provides a basis for investigating the metabolic mechanism of DMSP in extreme environments.     

海洋来源真菌Penicillium sp. wqh-572的次级代谢产物研究?

目的 研究浙江普陀岛海泥来源真菌Penicillium sp. wqh-572的次级代谢产物及其抑菌活性。方法 将菌株进行大规模发酵,乙酸乙酯萃取,采用小孔树脂MCI柱和半制备型高效液相色谱等分离纯化方法,通过核磁(₁H NMR和₁₃C NMR)和质谱(MS)等波谱分析方法,并与相关文献比较,鉴定化合物结构。结果 从该真菌发酵液的乙酸乙酯萃取相中分离得到6个化合物,鉴定结果分别为physcion (1)、emodin (2)、7-hydroxy-2-(2-hydroxypropyl)-5-methylchromone (3)、isorhodoptilometrin (4)、2-(2’, 4’, 6’-trihydroxyphenyc)-(7-hydroxy-5-methyc) chromone (5)及(Z)-N-(4-hydroxy styryl) formamide (6)。其中,其中化合物5为首次从青霉属真菌中分离得到。化合物1对3种植物病原菌均具有抑制作用。     

Haloferax sulfurifontis GUMFAZ2 producing xylanase‐free cellulase retrieved from Haliclona sp. inhabiting rocky shore of Anjuna,Goa‐India

Salt stable cellulases are implicated in detritic food webs of marine invertebrates for their role in the degradation of cellulosic material. A haloarchaeon, Haloferax sulfurifontis GUMFAZ2 producing cellulase was successfully isolated from marine Haliclona sp., a sponge inhabiting the rocky intertidal region of Anjuna, Goa. The culture produced extracellular xylanase‐free cellulase with a maximum activity of 11.7 U/ml, using carboxymethylcellulose‐Na (CMC‐Na), as a sole source of carbon in 3.5 M NaCl containing medium, pH 7 at 40°C and produced cellobiose and glucose, detectable by thin‐layer chromatography. Nondenaturing polyacrylamide gel electrophoresis of the crude enzyme, revealed a single protein band of 19.6 kDa which on zymographic analysis exhibited cellulase activity while corresponding sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed a molecular weight of 46 kDa. Unlike conventional cellulases, this enzyme is active in presence of 5 M NaCl and does not have accompanying xylanase activity, hence can be considered as xylanase‐free cellulase. Such enzymes from haloarchaea offer great potential for biotechnological application because of their stability at high salinity and is therefore worth pursuing.     

Impact of total body weight on acute kidney injury in patients with gram-negative bacteremia

Background: The impact of total body weight (TBW) on the development of acute kidney injury (AKI) associated with gram-negative bacteremia has not been previously evaluated.

Methods: The cohort included 323 patients >/ = 18 years old with gram-negative bacteremia (1/1/2008–8/31/2011) who received >/ = 48 hours of antibiotics. We compared the incidence of AKI in patients with a TBW </ = 80kg vs. >80kg with a multivariable stepwise logistic regression adjusting for age >/ = 70 years, baseline serum creatinine of > 2.0 mg/dl, and receipt of a vasopressor. AKI was defined as an increase of 0.5 mg/dL or a > 50% increase from baseline for at least two consecutive days.

Results: The cohort was 62% TBW </ = 80kg and 38% TBW >80kg. TBW >80kg patients had higher risk of AKI (24% vs. 9%, p < 0.001), which was significant in the multivariable analysis (OR 3.41, 95% CI 1.73–6.73). A baseline serum creatinine of > 2.0 mg/dl and vasopressor use were also independently associated with AKI.

Conclusions: TBW >80kg was associated with the development of AKI. However, the mechanism for this association is not clear.     

恒山黄芪内生真菌Aspergillus sp.中环二肽的分离和鉴定

目的:研究黄芪内生真菌AR-15-1的环二肽类次生代谢产物的成分。方法:内生真菌AR-15-1是采用组织学方法分离自恒山黄芪的根部,真菌的鉴定采用形态学法结合分子生物学法,内生真菌大量发酵采用固体培养的方法,环二肽成分的分离使用柱色谱法,HPLC法结合LH-20羟丙基葡聚糖凝胶色谱进行分离纯化,化合物结构鉴定采用波谱表征分析。结果:从黄芪根部分离到的内生真菌AR-15-1被鉴定为曲霉属Aspergillus sp.,从AR-15-1的固体发酵物中分离到8个环二肽化合物,分别为环(脯-甘)二肽(1),环(脯-亮)二肽(2),环(脯-异亮)二肽(3),环(脯-缬)二肽(4),环(苯丙-甘)二肽(5),环(苯丙-丙)二肽(6),环(苯丙-络)二肽(7)和环(苯丙-脯)二肽(8)。结论:环二肽类化合物1~8均为首次从黄芪内生真菌中分离得到,其中大部分环二肽化合物已被发现是具有很好的生物活性。     

镉胁迫对文山川芎矿质营养吸收和分配的影响

[目的]通过水培实验,研究不同浓度镉(Cd)处理下,文山川芎不同器官的镉吸收、分配特性及对其他12种矿质元素含量的影响,以为其安全利用提供科学依据。[方法]以文山川芎为实验材料,采用电感耦合等离子体发射光谱仪(ICP-MS),测定0、50、100μmol/L氯化镉(CdCl2)处理下,须根、根茎、地上茎及叶片中Cd及铁(Fe)、锌(Zn)、锰(Mn)、铜(Cu)、硼(B)、钼(Mo)、镁(Mg)、钙(Ca)、硫(S)、钾(K)、磷(P)、钠(Na)含量。[结果]镉胁迫下,文山川芎各部分Cd的积累表现为须根根茎地上茎叶。镉处理可显著影响文山川芎各器官中无机元素含量,与对照相比,须根中元素含量发生显著改变的有9种,根茎中8种,地上茎中7种,叶中8种。[结论]文山川芎药用、食用部位均有较强的镉积累能力,镉处理可显著破坏4种器官中无机元素间的平衡,影响其药用及食用质量。     

质谱导向的肾指海绵Reniochalina sp.中环肽类成分研究

目的 以质谱为导向对肾指海绵Reniochalina sp.中的环肽类成分进行研究。方法 采用质谱引导的程序性分离手段定向追踪并分离纯化海绵中的环肽类成分;通过理化常数测定、波谱数据比对确定化合物结构;利用CCK-8法对化合物进行初步细胞毒活性评价。结果 从肾指海绵Reniochalina sp.中分离获得3个环肽类化合物,分别鉴定为stylopeptide 1 (1)、hymenamide D (2)、axinastatin 2 (3)。化合物1对6种人肿瘤细胞株具有细胞毒性,IC₅₀值范围为6.09 ~ 17.26 μmol/L。结论 化合物1 ~ 3首次分离自Reniochalina属海绵,化合物1是细胞毒性环七肽。