Genomewide evolutionary rates in laboratory and wild yeast

As wild organisms adapt to the laboratory environment, they become less relevant as biological models. It has been suggested that a commonly used S. cerevisiae strain has rapidly accumulated mutations in the lab. We report a low-to-intermediate rate of protein evolution in this strain relative to wild isolates.     

Determination of tetracycline, chlortetracycline and oxytetracycline by flow injection with inhibitory chemiluminescence detection using copper(II) as a probe ion.

This paper reports an indirect flow-injection (FI) method for the determination of the tetracycline drugs (TCs), tetracycline (TC), chlortetracycline (CTC) and oxytetracycline (OTC), using copper(II) as a probe ion. The method was based on the inhibition caused by these TCs to the copper(II)-catalysed chemiluminescence (CL) reaction between luminol and H(2)O(2). The CL reaction was induced on-line and injection of the sample produced negative peaks as a result of the copper(II) complexation or displacement by the analytes. The height of the peaks was proportional to the drug concentration in the sample. The choice of the catalyst ion, the concentration of luminol, H(2)O(2) and copper(II) are discussed. The linear range was 3.6 x 10(-8)-1.0 x 10(-5), 1.1 x 10(-7)-1.0 x 10(-5) and 1.9 x 10(-7)-1.0 x 10(-5) mol/L for TC, CTC and OTC, respectively. The detection limit was 5.0 x 10(-9) mol/L for TC, 1.0 x 10(-8) mol/L for CTC and 2.0 x 10(-8) mol/L for OTC (3sigma), respectively. The method was applied to the determination of TCs in pharmaceutical preparations and human urine with recoveries in the range 95-105%.     

高效的植物DNA提取方法

利用液氮研磨植物幼芽,以苯酚─氯仿─异戊醇─核糖核酸酶法提取了大豆、菜豆、玉米、高梁等几种农作物的总ＤＮＡ。所提取的ＤＮＡ经岛津ＵＶ－２６５紫外分光光度计检测及０．６％的琼脂糖凝胶电泳,结果证明：该方法所提取的植物总ＤＮＡ纯度高,片段长度整齐,约５０ｋｂ左右,符合外源ＤＮＡ导入作物的要求,并且ＤＮＡ收率很高。     

Pseudomonas nitritireducens sp. nov., a nitrite reduction bacterium isolated from wheat soil

A Gram-negative, non-mobile, polar single flagellum, rod-shaped bacterium WZBFD3-5A2^T was isolated from a wheat soil subjected to herbicides for several years. Cells of strain WZBFD3-5A2^T grow optimally on Luria-Bertani agar medium at 30?°C in the presence of 0–4.0?% (w/v) NaCl and pH 8.0. 16S rRNA gene sequence analysis revealed that strain WZBFD3-5A2^T belongs to the genus Pseudomonas. Physiological and biochemical tests supported the phylogenetic affiliation. Strain WZBFD3-5A2^T is closely related to Pseudomonas nitroreducens IAM1439^T, sharing 99.7?% sequence similarity. DNA–DNA hybridization experiments between the two strains showed only moderate reassociation similarity (33.92?±?1.0?%). The DNA G+C content is 62.0?mol%. The predominant respiratory quinine is Q-9. The major cellular fatty acids present are C_16:0 (28.55?%), C_16:1ω6c or C_16:1ω7c (20.94?%), C_18:1ω7c (17.21?%) and C_18:0 (13.73?%). The isolate is distinguishable from other related members of the genus Pseudomonas on the basis of phenotypic and biochemical characteristics. From the genotypic, chemotaxonomic and phenotypic data, it is evident that strain WZBFD3-5A2^T represents a novel species of the genus Pseudomonas, for which the name Pseudomonas nitritereducens sp. nov. is proposed. The type strain is WZBFD3-5A2^T (=CGMCC 1.10702^T?=?LMG 25966^T).     

Glycoforms of UT-A3 urea transporter with poly-N-acetyllactosamine glycosylation have enhanced transport activity

Urea transporters UT-A1 and UT-A3 are both expressed in the kidney inner medulla. However, the function of UT-A3 remains unclear. Here, we found that UT-A3, which comprises only the NH(2)-terminal half of UT-A1, has a higher urea transport activity than UT-A1 in the oocyte and that this difference was associated with differences in N-glycosylation. Heterologously expressed UT-A3 is fully glycosylated with two glycoforms of 65 and 45 kDa. By contrast, UT-A1 expressed in HEK293 cells and oocytes exhibits only a 97-kDa glycosylation form. We further found that N-glycans of UT-A3 contain a large amount of poly-N-acetyllactosamine. This highly glycosylated UT-A3 is more stable and is enriched in lipid raft domains on the cell membrane. Kifunensine, an inhibitor of α-mannosidase that inhibits N-glycan processing beyond high-mannose-type N-glycans, significantly reduced UT-A3 urea transport activity. We then examined the native UT-A1 and UT-A3 glycosylation states from kidney inner medulla and found the ratio of 65 to 45 kDa in UT-A3 is higher than that of 117 to 97 kDa in UT-A1. The highly stable expression of highly glycosylated UT-A3 on the cell membrane in kidney inner medulla suggests that UT-A3 may have an important function in urea reabsorption.