Activity of lactoperoxidase when adsorbed on protein layers

Lactoperoxidase (LPO) is an enzyme, which is used as an antimicrobial agent in a number of applications, e.g., food technology. In the majority of applications LPO is added to a homogeneous product phase or immobilised on product surface. In the latter case, however, the measurements of LPO activity are seldom reported. In this paperwe have assessed LPO enzymatic activity on bare and protein modified gold surfaces by means of electrochemistry. It was found that LPO rapidly adsorbs to bare gold surfaces resulting in an amount of LPO adsorbed of 2.9mg/m2. A lower amount of adsorbed LPO is obtained if the gold surface is exposed to bovine serum albumin, bovine or human mucin prior to LPO adsorption. The enzymatic activity of the adsorbed enzyme is in general preserved at the experimental conditions and varies only moderately when comparing bare gold and gold surface pretreated with the selected proteins. The measurement of LPO specific activity, however, indicate that it is about 1.5 times higher if LPO is adsorbed on gold surfaces containing a small amount of preadsorbed mucin in comparison to the LPO directly adsorbed on bare gold

Effect of nonionic and amphoteric surfactants on salivary pellicles reconstituted in vitro

Surfactants are important components of oral care products. Sodium dodecyl sulfate (SDS) is the most common because of its foaming properties, taste and low cost. However, the use of ionic surfactants, especially SDS, is related to several oral mucosa conditions. Thus, there is a high interest in using non‐ ionic and amphoteric surfactants as they are less irritant. To better understand the performance of these surfactants in oral care products, we investigated their interaction with salivary pellicles i.e., the proteinaceous films that cover surfaces exposed to saliva. Specifically, we focused on pentaethylene glycol monododecyl ether (C12E5) and cocamidopropyl betaine (CAPB) as model nonionic and amphoteric surfactants respectively, and investigated their interaction with reconstituted salivary pellicles with various surface techniques: Quartz Crystal Microbalance with Dissipation, Ellipsometry, Force Spectroscopy and Neutron Reflectometry. Both C12E5 and CAPB were gentler on pellicles than SDS, removing a lower amount. However, their interaction with pellicles differed. Our work indicates that CAPB would mainly interact with the mucin components of pellicles, leading to collapse and dehydration. In contrast, exposure to C12E5 had a minimal effect on the pellicles, mainly resulting in the replacement/solubilisation of some of the components anchoring pellicles to their substrate

A comparison between the structures of reconstituted salivary pellicles and oral mucin (MUC5B) films

Hypothesis: Salivary pellicles i.e., thin films formed upon selective adsorption of saliva, protect oral surfaces against chemical and mechanical insults. Pellicles are also excellent aqueous lubricants. It is generally accepted that reconstituted pellicles have a two-layer structure, where the outer layer is mainly composed of MUC5B mucins. We hypothesized that by comparing the effect of ionic strength on reconstituted pellicles and MUC5B films we could gain further insight into the pellicle structure. Experiments: Salivary pellicles and MUC5B films reconstituted on solid surfaces were investigated at different ionic strengths by Force Spectroscopy, Quartz Crystal Microbalance with Dissipation, Null Ellipsometry and Neutron Reflectometry. Findings: Our results support the two-layer structure for reconstituted salivary pellicles. The outer layer swelled when ionic strength decreased, indicating a weak polyelectrolyte behavior. While initially the MUC5B films exhibited a similar tendency, this was followed by a drastic collapse indicating an interaction between exposed hydrophobic domains. This suggests that mucins in the pellicle outer layer form complexes with other salivary components that prevent this interaction. Lowering ionic strength below physiological values also led to a partial removal of the pellicle inner layer. Overall, our results highlight the importance that the interactions of mucins with other pellicle components play on their structure

Tillgänglighet, närhet och synlighet – gemensamma utmaningar för LUB-nätverket för att möta forskares behov av stöd vid Lunds universitet

This report presents a project at Lund University Libraries (LUB) during the fall of 2012, with the object to identify areas where the present research support services ought to be developed and strengthened. The project is three folded and contains a) a literature review focusing on definitions and examples of research support services as well as researchers’ needs and experiences of support services, b) a survey to get an overview of the support services offered today at LUB, the decentralized library network at Lund University, and c) focus group interviews with researchers, one group from each partaking faculty, to investigate key obstacles in their research processes. In all three parts a model of the research process schematically divided into four phases was applied; to start a project, to collect material, to process/analyze/write and to communicate the results. The first two stages of the project, the literature overview and the survey, form a background and both show that many support services are concentrated around the phases to collect material and to communicate results. The findings from the focus group interviews point to common needs and issues as well as special needs and issues related to different ways of doing and communicating research. Common for most researchers is limited time, a need for funding and an everyday fragmentation. They talk about the importance of networks, their efforts to navigate in an abundance of material and ways to find it and a need for overviews and help to understand new ways and demands to communicate. Most concern is expressed in the phases to start a project, to collect material and to communicate results. A major conclusion is that the research support services need to be available, visible and in close proximity to the researchers. Further, the development of support services needs to take into consideration both common traits as well as local variations in research practices. Therefore, discussions concerning LUB as a whole, need to be related to discussions at the single faculty libraries. Apart from knowledge about how to address the research support services at LUB, the project generates a model for how librarians can understand the research community that they are working with and with whom to create networks and partnerships for the future

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