Expanding the Versatility of Phage Display I: Efficient Display of Peptide-Tags on Protein VII of the Filamentous Phage

Background: Phage display is a platform for selection of specific binding molecules and this is a clear-cut motivation for increasing its performance. Polypeptides are normally displayed as fusions to the major coat protein VIII (pVIII), or the minor coat protein III (pIII). Display on other coat proteins such as pVII allows for display of heterologous peptide sequences on the virions in addition to those displayed on pIII and pVIII. In addition, pVII display is an alternative to pIII or pVIII display. Methodology/Principal Findings: Here we demonstrate how standard pIII or pVIII display phagemids are complemented with a helper phage which supports production of virions that are tagged with octa FLAG, HIS6 or AviTag on pVII. The periplasmic signal sequence required for pIII and pVIII display, and which has been added to pVII in earlier studies, is omitted altogether. Conclusions/Significance: Tagging on pVII is an important and very useful add-on feature to standard pIII and pVII display. Any phagemid bearing a protein of interest on either pIII or pVIII can be tagged with any of the tags depending simply on choice of helper phage. We show in this paper how such tags may be utilized for immobilization and separation as well as purification and detection of monoclonal and polyclonal phage populations. © 2011 Wälchli et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Expanding the Versatility of Phage Display II: Improved Affinity Selection of Folded Domains on Protein VII and IX of the Filamentous Phage

Background: Phage display is a leading technology for selection of binders with affinity for specific target molecules. Polypeptides are normally displayed as fusions to the major coat protein VIII (pVIII) or the minor coat protein III (pIII). Whereas pVIII display suffers from drawbacks such as heterogeneity in display levels and polypeptide fusion size limitations, toxicity and infection interference effects have been described for pIII display. Thus, display on other coat proteins such as pVII or pIX might be more attractive. Neither pVII nor pIX display have gained widespread use or been characterized in detail like pIII and pVIII display. Methodology/Principal Findings: Here we present a side-by-side comparison of display on pIII with display on pVII and pIX. Polypeptides of interest (POIs) are fused to pVII or pIX. The N-terminal periplasmic signal sequence, which is required for phage integration of pIII and pVIII and that has been added to pVII and pIX in earlier studies, is omitted altogether. Although the POI display level on pIII is higher than on pVII and pIX, affinity selection with pVII and pIX display libraries is shown to be particularly efficient. Conclusions/Significance: Display through pVII and/or pIX represent platforms with characteristics that differ from those of the pIII platform. We have explored this to increase the performance and expand the use of phage display. In the paper, we describe effective affinity selection of folded domains displayed on pVII or pIX. This makes both platforms more attractive alternatives to conventional pIII and pVIII display than they were before. © 2011 Wälchli et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Demersal Fish Assemblages and Spatial Diversity Patterns in the Arctic-Atlantic Transition Zone in the Barents Sea

Direct and indirect effects of global warming are expected to be pronounced and fast in the Arctic, impacting terrestrial, freshwater and marine ecosystems. The Barents Sea is a high latitude shelf Sea and a boundary area between arctic and boreal faunas. These faunas are likely to respond differently to changes in climate. In addition, the Barents Sea is highly impacted by fisheries and other human activities. This strong human presence places great demands on scientific investigation and advisory capacity. In order to identify basic community structures against which future climate related or other human induced changes could be evaluated, we analyzed species composition and diversity of demersal fish in the Barents Sea. We found six main assemblages that were separated along depth and temperature gradients. There are indications that climate driven changes have already taken place, since boreal species were found in large parts of the Barents Sea shelf, including also the northern Arctic area. When modelling diversity as a function of depth and temperature, we found that two of the assemblages in the eastern Barents Sea showed lower diversity than expected from their depth and temperature. This is probably caused by low habitat complexity and the distance to the pool of boreal species in the western Barents Sea. In contrast coastal assemblages in south western Barents Sea and along Novaya Zemlya archipelago in the Eastern Barents Sea can be described as diversity “hotspots”; the South-western area had high density of species, abundance and biomass, and here some species have their northern distribution limit, whereas the Novaya Zemlya area has unique fauna of Arctic, coastal demersal fish. (see Information S1 for abstract in Russian)

Hydrographical monitoring emphasising dissolved oxygen at EWOS Innovation Oltesvik 2003

This report describes monitoring of hydrographic conditions and salmon performance at EWOS Innovation Oltesvik in 2003. During the period March – October, dissolved oxygen (DO) and other linked parameters were continuously monitored outside and within cages stocked with salmon of 1 – 4 kg transferred to sea as smolt in spring 2002. The fish stock was badly influenced by high temperature and occasionally low DO concentrations in September – October 2002. From 11 June until start starvation in mid-October, three cages were added oxygen. DO concentrations, fish growth and feed utilisation were compared between cages added oxygen and reference cages (two cages without oxygen addition). Besides, feed consumption was measured on an hourly – daily basis in all five cages and these results will be presented in another report.OSV, EWO

Clinical course of chronic periodontitis. II. Incidence, characteristics and time of occurrence of the initial periodontal lesion.

AIM: The purpose of this study was to assess the initiation and progression of periodontal disease during adult life. MATERIALS AND METHODS: In a 26-year longitudinal investigation of the initiation and progression of chronic periodontitis that started in 1969 and included 565 men of Norwegian middle class, 223 who had participated in some, but not all, intermediate examinations presented at the last survey in 1995. Fifty-four individuals were available for examination in all seven surveys. RESULTS: Covering the age range from 16 to 60 years, the study showed that at 16 years of age, 5% of the participants had initial loss of periodontal attachment (ILA > or = 2 mm) at one or more sites. Both the subject incidence and the site incidence increased with time, and by 32 years of age, all individuals had one or more sites with loss of attachment. As age progressed, new lesions affected sites, so that as these men approached 60 years of age approximately 50% of all available sites had ILA. An assessment of the intraoral distribution of the first periodontal lesion showed that, regardless of age, molars and bicuspids were most often affected. At and before the age of 40 years, the majority of ILA was found in buccal surfaces in the form of gingival recession. By 50 years, however, a greater proportion of sites presented with attachment loss attributed to pocket formation or a combination of pocket formation and gingival recession. As individuals neared 60 years of age, approximately half of the interproximal areas in posterior teeth had these lesions. CONCLUSION: This investigation has shown that, in a well-maintained population who practises oral home care and has regular check-ups, the incidence of incipient periodontal destruction increases with age, the highest rate occurs between 50 and 60 years, and gingival recession is the predominant lesion before 40 years, while periodontal pocketing is the principal mode of destruction between 50 and 60 years of age

Temporal and vertical variations of chlorophyll concentrations in high mountain lakes of the Adamello-Brenta Regional Park (Trentino, Italy)

Chlorophyll has been commonly used to estimate algal biomass and trophic levels of lakes. Chlorophyll, being the result of interactions between physical, chemical and biological factors, can also show the effects of human impacts, such as fish introduction or removal, or water-level fluctuations, correlated to the use o f lakes as reservoirs. Beyond the more traditional use for rhe assessment of trophic status, chlorophyll determinations may also be of interest in the context of regional studies to improve the characterisation of high mountain lakes. The seasonal study of chlorophyll concentrations in two lakes suggested a temporary change of the trophic level in Tre Laghi and showed differences in the amount of primary production in two apparently similar lakes. A possible explanation might be a higher grazing pressure on phytoplankton occurring in Lake Serodoli, where fish is lacking, while Lake Tre Laghi is occasionally and illegally stocked with young Salvelinus fontinalis and Salmo trutta forio, which live on zooplankton. However, in discussing the biological differences between the two lakes, the exploitation of the water of Lake Serodoli should also be considered. Indeed until 1990 the lake was almost emptied in winter for hydroelectric purposes by means of a pipe located at a depth of 20 m; today 50-60 L s-' are taken away in winter as drinking water, causing a water level reduction of 3-4 m only. Additional data must be collected for a deep understanding of this situation, indicating the need for detailed limnological research even in apparently undisturbed high mountain lakes in Nature Parks in ltaly