Proton resonance assignments for Pseudomonas aeruginosa ferrocytochrome c-551.

A comparison between two sets of resonance assignments for ferrocytochrome c-551 from Pseudomonas aeruginosa reveals that major differences can be explained by pH effects. In turn, these reveal side chain protonation events in c-551 that markedly influence spectra. The behavior of resonances in a homologous protein from Pseudomonas stutzeri help to clarify ambiguities in the P. aeruginosa case. A corrected and completed set of proline assignments is presented. Labile side chain protons in residue 47, which hydrogen bonds to the inner heme propionate, appear to be in fast exchange with the solvent.     

Biotinylation of double stranded DNA after transamination

The bisulfite catalyzed transamination of cytidine and cytosine has been reported to be single strand specific, but local thermal instabilities of the DNA double helix, coupled with the extreme sensitivity of the Biotin-Avidin revelation methods, allows the random labelling of cytosines in d.s. DNA to detectable levels for those purposes where the overall label can be very low. We have evaluated the use of this reaction to prepare double stranded DNA molecules containing N4-aminoethyl-cytosine (4-aeC). After this step 4-aeC residues can be conjugated to biotinyl-n-hydroxysuccinimide ester yielding biotinylated DNA. This reaction allows the massive production of biotinylated probes. Labelled DNA can serve as molecular weight marker and positive control in Southern-blots. Moreover it can be useful in the study of DNA-protein interaction and in the isolation of d.s. DNA-binding proteins through chromatographic procedures.     

The expression of granulocyte/macrophage colony-stimulating factor in activated mouse lymphocytes declines with age

The expression of granulocyte/macrophage colony-stimulating factor (GM-CSF) was studied in spleen lymphocytes isolated from male C57BL/6J mice of 6, 20, and 29 months of age. GM-CSF expression (biological activity and mRNA level) was maximum after culturing the lymphocytes for 45 hr with concanavalin A and phorbol myristate acetate. The induction of both GM-CSF activity and mRNA levels was observed to decline over 60% between 6 and 29 months of age. The age-related decline in the level of GM-CSF paralleled the age-related decline in the mRNA levels of interleukin-2 and interleukin-3.     

益生菌调控肠道屏障功能预防家禽球虫病的研究进展

球虫病给养禽业带来巨大经济损失,人们对绿色健康食品的迫切需求使球虫病的防控面临新的挑战.伴随世界"禁抗"进程的不断推进,家禽养殖业亟需一种安全有效的新型抗球虫方法.益生菌可竞争性排斥病原菌定殖以防止球虫病继发感染,可刺激宿主抗菌肽、黏蛋白和紧密连接蛋白的分泌以抵御球虫入侵,还可激活免疫反应以增强机体抗球虫感染的能力.本...