Novel cytotoxic exhibition mode of antimicrobial peptide anoplin in MEL cells,the cell line of murine Friend leukemia virus‐induced leukemic cells

Anoplin is a recently discovered antimicrobial peptide (AMP) isolated from the venom sac of the spider wasp Anoplius samariensis, and it is one of the shortest α‐helical AMP found naturally to date consisting of only ten amino acids. Previous results showed that anoplin exhibits potent antimicrobial activity but little hemolytic activity. In this study, we synthesized anoplin, studied its cytotoxicity in Friend virus‐induced leukemia cells [murine erythroleukemia (MEL) cells], and proposed its possible mechanism. Our results showed that anoplin could inhibit the proliferation of MEL cells in a dose‐dependent and time‐dependent manner via disrupting the integrity of cell membrane, which indicated that anoplin exerts its cytotoxicity efficacy. In addition, the cell cycle distribution of MEL cells was arrested in the G₀/G₁ phase significantly. However, anoplin could not induce obvious apoptosis in MEL cells, as well as anoplin could not induce visible changes on morphology and quantity in the bone marrow cells isolated from normal mice. All of these results indicate that anoplin, as generally believed, is a selective AMP, a value characteristic in the design of safe therapeutic agents. The cytotoxicity of anoplin on MEL cells was mainly attributable to the plasma membrane perturbation and also to the intracellular events such as the arrest of cell cycle. Although this is an initial study that explored the activity of anoplin in vitro rather than in vivo, with the increasing resistance of conventional chemotherapy, there is no doubt that anoplin has desirable feature to be developed as a novel and selective anticancer agent. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.     

Purification and Characterization of the Pasteurella Haemolytica 35 Kilodalton Periplasmic Iron-Regulated Protein

ABSTRACT

Pasteurella haemolytica serovar A1 is the causative agent of acute fibrinohemorrahgic pneumonia also known as shipping fever. Many pathogens, including P. haemolytica, survive in their respective hosts through the up-regulation of an iron acquisition system. In this study we identified, purified and characterized a 35-kDa periplasmic iron-regulated protein. The N-terminal sequence of the iron-regulated protein ANEVNVYSYRQP YLIEPMLK was identical to the deduced amino acid sequence of the ferric binding protein, FbpA, of P. haemolytica. Growth of P. haemolytica in a synthetic medium (RPMI-1640), without iron and supplemented with 50 μM 2,2' dipyridyl, facilitated the expression, isolation and purification of the native P. haemolytica FbpA.     

Concentration of Virus from Water by Electro-Osmosis and Forced-Flow Electrophoresis. II. Improvement of Methodology and Application to Tap Water

The ability of the Canalco Model CF-3 electro-osmosis (EO) apparatus to concentrate viruses from artificially seeded distilled water was improved. Modification of the physical arrangement of the equipment allowed for a 10–25 fold increase in concentration efficiency and a concomitant decrease in the process time. The major improvements involved modifications of the cell arrangement (which increased the membrane transport area), a change in the salt replenishing solution and the use of different membranes of higher flux. Viruses concentrated by E0 from seeded tap water resulted in lower recoveries when compared to distilled water. The lower yields were probably due to instability or aggregation of the agents in the menstruum and not directly related to the physical apparatus. Under the conditions used, one could detect virus at levels as low as 0.01 plaque forming units (PFU) per ml of initial input. The efficacy of a modification of the Canalco forced-flow electrophoretic (FFE) system was also evaluated. The maximum potential was applied with a constant value for pump rates. A 6-fold concentration of virus and a 12-fold decrease in water volume was obtained.     

Isolation of Four Isomers of the 20,000 Dalton Variant of Human Pituitary Growth Hormone

A simple procedure has been developed which for the first time describes the isolation of isomers of the 20, 000 dalton variant of human growth hormone (20K hGH). From a human pituitary hormone concentrate different hGH dimers (covalently and noncova-lently linked) were enriched by chromatography on SP-Sephadex C-50, DEAE-Sepharose CL-6B and Sephadex G-100. Noncovalently-1inked dimers were split by 6 M urea into 20K hGH and 22K hGH monomers. A complete group-separation of 20K hGH and 22K hGH monomers was achieved by chromatography on DEAE-Sepharose CL-6B at neutral pH. The 20K hGH monomer was resolved into four isomers either by preparative isoelectric focusing or by zone electrophoresis in agarose suspension at alkaline pH. The three latter techniques were all used in the presence of 6 M urea. Radioimmunoassay and radioreceptorassay indicated that the isomers obtained were true components of human growth hormone.     

Removal of Triosephosphate,Isomerase from Albumins

Commercial serum albumin and ovalbumin from a variety of sources contain triosephosphate isomerase activity which can interfere with many enzyme assays and metabolic studies. A simple procedure is described for the removal of this contaminant by preparative electrophoresis or electrofocus-ing.