Novel Antifreeze Protein Constructs for Improved Activity

Many organisms are exposed to subzero temperatures in nature and can survive these temperatures by the effect of antifreeze proteins (AFPs), which inhibit ice crystal growth and change the morphology of ice crystals. Although the effects of these proteins, such as recrystallization inhibition, ice growth inhibition, and crystal habit changes, are known, a conclusive description of the protein-ice crystal interaction including interaction energy, surface coverage, and lifetime of adsorbate has been elusive. In this study, different antifreeze protein constructs are designed and expressed such that they can be conjugated to polymers to increase the thermal hysteresis activity especially at low concentrations. Trimers of these proteins are also constructed using a foldon domain attached to their C-terminus. New constructs of type I and type III antifreeze proteins yield significantly higher thermal hysteresis activities than the native protein. Furthermore, we determine the binding equilibrium constant for a type III fish antifreeze protein and the relationship between thermal hysteresis and surface coverage for this protein. This is possible using experimental data from a two-domain antifreeze protein and its related single domain protein. The classical Langmuir isotherm is used to describe the equilibrium exchange of the single domain type III AFP molecules at the ice crystal surface, while a modification of the Langmuir isotherm is derived to describe the adsorption of the two-domain AFP. Because the protein adsorption is governed by different isotherm relationships, there are two independent data sets allowing the determination of the two unknowns of surface coverage and binding energy. The data yield a binding equilibrium constant of 1.9 mM-1 for the type III AFP-ice interaction. The analysis results in a relationship between surface coverage and thermal hysteresis, as well as kinetic equations of the adsorption of the proteins onto the ice surfac

Novel Antifreeze Protein Constructs for Improved Activity

Many organisms are exposed to subzero temperatures in nature and can survive these temperatures by the effect of antifreeze proteins (AFPs), which inhibit ice crystal growth and change the morphology of ice crystals. Although the effects of these proteins, such as recrystallization inhibition, ice growth inhibition, and crystal habit changes, are known, a conclusive description of the protein-ice crystal interaction including interaction energy, surface coverage, and lifetime of adsorbate has been elusive. In this study, different antifreeze protein constructs are designed and expressed such that they can be conjugated to polymers to increase the thermal hysteresis activity especially at low concentrations. Trimers of these proteins are also constructed using a foldon domain attached to their C-terminus. New constructs of type I and type III antifreeze proteins yield significantly higher thermal hysteresis activities than the native protein. Furthermore, we determine the binding equilibrium constant for a type III fish antifreeze protein and the relationship between thermal hysteresis and surface coverage for this protein. This is possible using experimental data from a two-domain antifreeze protein and its related single domain protein. The classical Langmuir isotherm is used to describe the equilibrium exchange of the single domain type III AFP molecules at the ice crystal surface, while a modification of the Langmuir isotherm is derived to describe the adsorption of the two-domain AFP. Because the protein adsorption is governed by different isotherm relationships, there are two independent data sets allowing the determination of the two unknowns of surface coverage and binding energy. The data yield a binding equilibrium constant of 1.9 mM-1 for the type III AFP-ice interaction. The analysis results in a relationship between surface coverage and thermal hysteresis, as well as kinetic equations of the adsorption of the proteins onto the ice surfac

Novel Antifreeze Protein Constructs for Improved Activity

Many organisms are exposed to subzero temperatures in nature and can survive these temperatures by the effect of antifreeze proteins (AFPs), which inhibit ice crystal growth and change the morphology of ice crystals. Although the effects of these proteins, such as recrystallization inhibition, ice growth inhibition, and crystal habit changes, are known, a conclusive description of the protein-ice crystal interaction including interaction energy, surface coverage, and lifetime of adsorbate has been elusive. In this study, different antifreeze protein constructs are designed and expressed such that they can be conjugated to polymers to increase the thermal hysteresis activity especially at low concentrations. Trimers of these proteins are also constructed using a foldon domain attached to their C-terminus. New constructs of type I and type III antifreeze proteins yield significantly higher thermal hysteresis activities than the native protein. Furthermore, we determine the binding equilibrium constant for a type III fish antifreeze protein and the relationship between thermal hysteresis and surface coverage for this protein. This is possible using experimental data from a two-domain antifreeze protein and its related single domain protein. The classical Langmuir isotherm is used to describe the equilibrium exchange of the single domain type III AFP molecules at the ice crystal surface, while a modification of the Langmuir isotherm is derived to describe the adsorption of the two-domain AFP. Because the protein adsorption is governed by different isotherm relationships, there are two independent data sets allowing the determination of the two unknowns of surface coverage and binding energy. The data yield a binding equilibrium constant of 1.9 mM-1 for the type III AFP-ice interaction. The analysis results in a relationship between surface coverage and thermal hysteresis, as well as kinetic equations of the adsorption of the proteins onto the ice surfac

Predictors of hybrid organizational identity: evidence from the Turkish theatre field, 1923-1999

Being an essential concept in organization research for a long time, organizational identity has received a renewed interest both theoretically and empirically since it has increasingly been interpreted as contingent, dynamic and multiple. Although the notion of hybrid identity constitutes an important part of this interest, existing research mostly considers it as a starting assumption without investigating why there are such identities in the first place. By borrowing ideas from institutional and imprinting frameworks in organization theory, this study is an attempt to extend research by examining how particular field and organization-level factors may predict hybridity of organizational identities. Focusing on the Turkish theatre field as the empirical setting, first the identity claim categories in the field were discovered via cluster analysis by using the dataset of plays performed by professional theatre companies in Istanbul and Ankara during the 1923- 1999 period. Next, analyses were conducted by using multilevel (mixed effect) models in order to test study hypotheses. Hybrid identity was measured by Simpson diversity index weighted by category contrasts. Findings reveal that the degree of identity hybridization is largely enhanced by the identity hybridity of the organization at its birth, the transition in institutional logics and the strength of the mimetic mechanisms within the field. The results emphasize that diverse identity claims are combined more under specific institutional and founding conditions

Demonstrating a powerful scale-up strategy for Biosimilar mAb in single use systems via physicochemical and functional characterization

Biosimilars have received a remarkable attention in the recent years. Due to the heterogeneity of biosimilar mAbs, they need to be well-characterized by various orthogonal techniques in order to identify their physicochemical and functional characteristics. Characterization of the post translational modifications, especially, glycosylation is vital to define the critical quality attributes (CQAs) which affect safety, efficacy and quality of drugs. In this study, we were able to manipulate the quality of the drug by using scale-up strategies for single use systems. By using ultra-performance liquid chromatography (UPLC) coupled to mass spectrometry (MS), we were able to demonstrate physicochemical similarities between innovator and its biosimilar candidate. Even the PTM (N-terminal pyroglutamic acid formation, C-terminal lysine truncation, methionine and tryptophan oxidation, asparagine deamidation, N-glycosylation and glycation) levels of two products from 3 and 200-liter single-use bioreactors were highly similar compared to the innovator. The mass spectrometry studies showed that the scale-up strategy from 3 liter to 200 liter was successful. Deconvoluted mass spectrum for intact and reduced masses (heavy and light chain) of innovator and its biosimilar candidates from different production scales were significantly similar. Oxidation was observed to be lower in 200 liter bioreactor compared to the 3 liter. The N-glycan profiles for the major and minor glycan species were highly similar compared to the originator. Aggregation level in 200 liter was slightly lower than that of the small scale production. Mass spectrometry becomes an important tool to enhance the biosimilarity to the originator in order to decrease the clinical efforts to be able to provide affordable drugs to the patients

Cytokine Profiles of Chronic Urticaria Patients and the Effects of Omalizumab Treatment

Introduction: Cytokines are key mediators in immunological and inflammatory conditions, including chronic spontaneous urticaria (CSU). Objectives: To investigate Th1, Th2, and Th17 cytokine profiles in CSU and to evaluate the possible effect of omalizumab treatment. Methods: Patients who were followed up for CSU, as well as healthy volunteers, were included in the study. To assess urticaria activity, the 7-day-Urticaria Activity Score (UAS-7), the Urticaria Control Test (UCT), and the Chronic Urticaria Quality of Life Questionnaire (CU-QoL) were filled. Serum levels of IL-6, IL-17, IL-31, eotaxin, RANTES, TNF-α, and TSLP were analyzed by ELISA and compared in CSU and control groups. The patients were analyzed in two groups as the omalizumab group and the non-omalizumab group based on their treatment status.   Results: Total IgE, ESR, CRP, RANTES, and TNF-a were significantly different in the overall comparison of the three groups: CSU-receiving omalizumab, CSU-not receiving omalizumab, and control groups (P <0.01, 0.015, <0.01, <0.01 and <0.01 respectively). Total IgE, CRP, RANTES, and TNF-α values were similar in those who received and did not receive omalizumab, yet these biomarkers were significantly higher in both groups than in the control group (P < 0.05). Statistical significance in ESR was observed only between the CSU-receiving omalizumab group and the control group (P = 0.01). Within the CSU patients, there was a slight but significant correlation between UCT and TNF-α (P = 0.008, r = 0.32) and IL-17 (P = 0.06, r = 0.33) levels. Conclusions: The investigated cytokine profile in CSU patients may differ from healthy controls, particularly with the higher levels of RANTES and TNF-α, and omalizumab treatment does not seem to affect that profile in CSU patients

Valuation of environmental improvements in a specially protected marine area: A choice experiment approach in Gocek Bay, Turkey

Although the Gocek Bay area was declared as a specially protected area by General Directorate of Natural Assets Protection, the region is threatened because of pollution resulting from increased boat tourism and lack of efficient policies. Extensive measures are being planned in order to protect the region. Coastal management requires the use of technical, social political and economic tools to create a comprehensive management strategy. For environmental investments, it is necessary that benefits and the costs of environmental improvements should be identified in monetary terms in order to determine the feasibility of the investments. The aim of this study is to determine the benefits of the management alternatives to improve environmental quality in Gocek Bay to aid decision makers. In this study, the environmental benefits that can be obtained with improved water quality and restored marine ecosystem were calculated using the Choice Experiment Method, a non-market valuation technique. Data were analyzed using Multinomial Logit Model and the results showed that, local residents and tourists are willing to pay 18 TL/month and 16.6 TL/tour, respectively for improvements in water quality. For improvements in marine life, local residents are willing to pay 14.8 TL/month and tourists are willing to pay 11.2 TL/tour. With this study, it has been seen that the results obtained will pave the way for new policies and measures against the deterioration of the marine environment of Gocek Bay

Affective and normative commitment to organization, supervisor, and coworkers: Do collectivist values matter?

Employees’ commitment to their organization is increasingly recognized as comprising of different bases (affect-, obligation-, or cost-based) and different foci (e.g., supervisor, coworkers). Two studies investigated affective and normative commitment to the organization, supervisor and coworkers in the Turkish context. The results of Study 1 confirmed that employees differentiate between affect versus obligation-based commitment towards the organization, supervisor and coworkers. Study 2 tested the “cultural hypothesis” which argues for the moderating influence of collectivistic values on the relationship between person (local) commitments and organizational level (global) outcomes. The results supported the “compatibility hypothesis” which posits that the relationship between a given attitude and other attitudes or behaviors is based on the attitudes and behaviors having the same targets. Taken together, the findings suggest that the influence of culture may be less straightforward and may require a more sophisticated measurement of the nature of relationships and organizational characteristics in general

Determinants of inter-firm networks among tenants of science technology parks

Science and technology parks (STPs) try to facilitate networking among their tenants by (i) creating a favorable ecology for collaboration through selection of tenants and (ii) encouraging the formation of ties among these firms through events and introductions. We investigate the effect of these interventions on data collected from managers and tenants of 12 STPs in Turkey. In analyses that include STP level fixed effects to control for unobserved heterogeneity in parks' characteristics, we find ecological characteristics as well as manager interventions to have some effect on prevalence of inter-firm relationships: Sectoral homogeneity is associated with greater numbers prevalence of knowledge sharing, joint development, and client ties. Tenants whose general managers have greater presence at the park have more equipment-sharing ties, and attendance at STP-organized events increases knowledge-sharing ties. STP managers’ brokerage activities contribute to equipment sharing ties