Purification and characterization of Clostridium botulinum type B oxin

Gerwing, Julia (The University of British Columbia, Vancouver, B.C., Canada), Claude E. Dolman, David V. Kason, and Jack H. Tremaine. Purification and characterization of Clostridium botulinum type B toxin. J. Bacteriol. 91:484-487. 1966.-A toxic component of low molecular weight has been isolated from a type B strain of Clostridium botulinum by methods involving ammonium sulfate precipitation and elution through diethylaminoethyl cellulose at pH 5.6. The material thus isolated was shown to be monophoretic and monodisperse in the ultracentrifuge. End-group analysis indicated the presence of a single N-terminal amino acid residue, which was identified as arginine. On the basis of biophysical studies and amino acid analyses, a molecular weight between 9,000 and 10,000 was calculated.     

The matrix affects trackway corridor suitability for an arenicolous specialist beetle

In conserving regional insect diversity dispersal corridors are advocated to counteract fragmentation and for resilience to climate change. However, influences of corridor design and management on their function are poorly understood. Effects of contrasting matrix structure on the suitability and function of trackways as corridors for dispersal of an arenicolous carabid beetle, Harpalus rufipalpis (Sturm), was studied within a plantation landscape using mark-release-recapture. A total of 1,120 marked H. rufipalpis were released into four trackways: two “open” trackways surrounded by pine plantations aged 13–16 years and two “shaded” trackways surrounded by plantations aged 26–37 years. Dispersal was monitored by a grid of pitfall transects placed across trackways at intervals of four meters, extending 44 m north and south of the release point. Numbers of resident and marked recaptured H. rufipalpis, their average daily movement rates and numbers of recaptures in the north and south direction were compared between open and shaded trackways using 238 recaptures. The surrounding matrix affected trackway suitability with greater abundance of resident beetles found in open trackways; however H. rufipalpis was also naturally present in shaded trackways. H. rufipalpis were more active in low quality shaded corridors as inferred from the greater number of recaptures and from greater daily movement rates. Corridor edge permeability differed between trackway types, with more individuals leaving the corridor to enter the matrix in the less suitable shaded trackways. Thus matrix type affected the potential habitat suitability and conduit function of trackway corridors.     

Membrane-covered thin-layer optical cell for gas-reaction studies of hemoglobin

A thin-layer sample cell, holding between 1 and 8 μl of hemoglobin solution between a glass window and a transparent gas-permeable membrane, has been developed for spectroscopic studies of hemoglobin reactions with gaseous ligands. The partial pressure of reactant gases is accurately changed through a set of equally spaced logarithmical values by means of a precision dilution valve connected to the sample cell. After a partial pressure change, a new equilibrium state is reached. The time required to establish this state, usually on the order of a few minutes, is dependent upon the sample thickness, affinity, concentration, and the degree of saturation. Sample thicknesses between 0.025 and 0.15 mm have been used for studies in the visible spectral region with hemoglobin concentrations varying between 0.5 and 15 mm heme. High stability of the sample geometry is indicated by constaney within 0.001 OD of a 0.5 OD hemoglobin sample over a period of 1 hr.     

Single copy nuclear DNA markers characterized for comparative phylogeography in Australian wet tropics rainforest skinks

In order to investigate population history and demography in skinks endemic to the wet tropics of Australia, multiple nuclear DNA markers were sought. The utility of 72 primers (including 63 published intron‐spanning ‘CATS’ primers) was tested. Seven loci were characterized and shown to be single copy by single‐strand conformation polymorphism analysis. Primers to five nuclear loci were developed, four with utility in skinks and three with utility in frogs. These observations extend the available information on intron‐spanning primers for amphibians and reptiles.     

Anti-A and anti-B activity in batches of different intravenous immunoglobulin products determined using a direct haemagglutination method.

The European Pharmacopoeia requires that manufacturers assess intravenous immunoglobulin (IVIG) products for antibodies against blood groups A and B using an indirect anti-globulin test (AGT). However, this method suffers from the disadvantage that the anti-globulin reagent may be neutralised by excess IgG and invalidate the data generated. In view of this, we have used a direct microtitre-based haemagglutination method to screen batches of IVIG products from five manufacturers for anti-A and anti-B, and compared the titres with those reported by the manufacturers. The range of reported titres varied 32-fold across the different products, whereas virtually all the direct method titres fell within a 4-fold range for each specificity. This indicated that the discrepancies in reported titres were due to inconsistencies in manufacturers' testing methodology and/or interpretation of results. Our finding that the anti-globulin reagent used to bring about agglutination of anti-A- or anti-B-sensitised erythrocytes in the AGT was neutralised by excess IgG at least down to a 1 in 8 dilution of IVIG (from 5% (w/v) IgG) casts serious doubts on the suitability of the AGT for testing high immunoglobulin concentration products.