A new species of Stenobiella Tillyard (Neuroptera, Berothidae) from Australia

Stenobiella variola sp. n., a new species of beaded lacewing (Neuroptera: Berothidae), is described and figured from south-eastern Australia. A preliminary key to Stenobiella species is presented

Adsorption of b-Lactoglobulin onto Silica, Methylated Silica and Polysulphone

Milk and whey are widely processed by membrane filtration, often using polysulphone membranes. Adsorption of β-lactoglobulin onto polysulphone was studied at protein concn. of 0.1 and 1.0%, as well as 12% to represent concn. encountered during ultrafiltration. Adsorption onto silica and methylated silica surfaces (representing strongly hydrophilic and strongly hydrophobic surfaces resp.) was also studied. Protein was dissolved in 0.01 smallcap˜M phosphate buffer pH 7.0 containing 0.15 smallcap˜M NaC1 and adsorption/desorption was monitored in situ using a Rudolph Thin Film ellipsometer. Polysulphone surfaces adsorbed the greatest amount of β-lactoglobulin and silica the least; methylated silica was intermediate. Differences between methylated silica and polysulphone may reflect differences in surface roughness. Adsorption to polysulphone and methylated silica was not reversed on dilution, whereas adsorption to silica was partially reversible. Pretreatment of polysulphone and methylated silica surfaces with 0.1% β-lactoglobulin markedly reduced subsequent adsorption from 12% β-lactoglobulin (equivalent to adsorption from 0.1% solution alone); preadsorption to silica surfaces had much less effect on subsequent adsorption. Methylated silica was concluded to be a representative model for a polysulphone surface

Removal of Lysozyme from Methylated Silica Surfaces by a Nonionic Surfactant Pentaethyleneglycol Mono n-Dodecyl Ether (C12E5)

The removal of lysozyme adsorbed to a hydrophobic surface by a non-ionic surfactant, C12E5, was investigated using in situ ellipsometry. Both the adsorption and removal of protein were studied at different protein and surfactant concentrations. The surfaces used were methylated silica surfaces and the experiments were carried out at pH 5.6 in 0.01 M NaCl solution. The adsorption isotherm of lysozyme did not reach a plateau level within the concentration range investigated and judging from the adsorbed amount at high protein concentrations the protein adsorbs at least in a bilayer. The adsorbed protein was only to a minor extent removed upon rinsing with buffer and addition of surfactant gave partial removal which was dependent on surfactant concentration and the amount of protein adsorbed. An increase in the surface concentration of protein led to a decrease in the fraction of the adsorbate that was removed due to surfactants. However, the absolute amount removed did not decrease but levelled off at 1.3 mg m−2. The removal of adsorbed lysozyme started at about the same surfactant concentration as that required for the surfactant to adsorb at the interface and the amount removed by surfactant increased with surfactant concentration up to half its cmc