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Abstract: Protein-based fish adhesives have historically been used in various bonding applications; however, due to the protein’s high affinity for water absorption, these adhesives become destabilized in high-moisture environments, resulting in reduced bondline strength and early failure. This limitation makes them unsuitable for industrial applications with higher demands. To address this issue, water-insoluble raw powder materials such as iron, copper, or zeolite were incorporated into natural fish adhesives. In this study, the hygroscopicity, dry matter content, thermal analysis (TGA/DSC), FT-IR spectroscopy, surface tension measurements, vapour permeability, and scanning electron microscope (SEM) of the modified adhesives were determined. In addition, the bonding properties of the modified adhesives were evaluated by the tensile shear strength of the lap joints, and mould growth was visually inspected. The resulting modified protein-based adhesives demonstrated improved stability in high humidity environments. Enhancing the hygroscopic properties of protein-based fish adhesives has the potential to unlock new opportunities and applications, providing a healthier and more environmentally sustainable alternative to petroleum-based adhesives.
Keywords: protein‐based adhesive, polymer stabilization, hygroscopicity, fish adhesive modification, fish industry waste, circular economy, bonding properties
Published in DiRROS: 12.08.2024; Views: 66; Downloads: 215
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Abstract: Recent studies have revealed that at lower cultivation temperatures (25 °C) much higher percentage of correctly folded recombinant hG-CSF protein can be extracted from inclusion bodies. Hence, the goal of our research was to investigate mechanisms determining characteristics of non-classical inclusion bodies production using gene expression profiling, focusing on proteases and chaperones gene expression. Statistical analysis of microarray data showed prominent changes in energy metabolism, in metabolism of amino acids and nucleotides, as well as in biosynthesis of cofactors and secondary metabolites if the culture was grown below its optimal temperature. Moreover, 24 differentially expressed up to now known genes classified among proteases, chaperones and other heat or stress related genes. Among chaperones UspE and among proteases YaeL and YeaZ might play an important role in accumulation of correctly folded recombinant proteins. Membrane localized protease yaeL gene was found to have higher activity at 25 °C and is thus potentially functionally related to the more efficient recombinant protein production at lower temperatures. The results of this study represent advance in the understanding of recombinant protein production in E. coli. Genes potentially influencing production of recombinant protein at lower growth temperature represent basis for further research towards improvement of E. coli production strains as well as fermentation process.
Keywords: recombinant protein production, non-classical inclusion bodies, expression microarrays, YaeL protease, GroEL chaperone
Published in DiRROS: 05.08.2024; Views: 222; Downloads: 208
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Abstract: Temperature is a fundamental environmental factor that shapes the evolution of organisms. Learning thermal determinants of protein sequences in evolution thus has profound significance for basic biology, drug discovery, and protein engineering. Here, we use a data set of over 3 million BRENDA enzymes labeled with optimal growth temperatures (OGTs) of their source organisms to train a deep neural network model (DeepET). The protein-temperature representations learned by DeepET provide a temperature-related statistical summary of protein sequences and capture structural properties that affect thermal stability. For prediction of enzyme optimal catalytic temperatures and protein melting temperatures via a transfer learning approach, our DeepET model outperforms classical regression models trained on rationally designed features and other deep-learning-based representations. DeepET thus holds promise for understanding enzyme thermal adaptation and guiding the engineering of thermostable enzymes.
Keywords: bioinformatics, deep neural networks, enzyme catalytic temperatures, optimal growth temperatures, protein thermostability, transfer learning
Published in DiRROS: 17.07.2024; Views: 152; Downloads: 125
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Keywords: energy, kinetics, molecules, protein structure, rotational dynamics, molecules, protein structure, rotational dynamics
Published in DiRROS: 06.09.2023; Views: 495; Downloads: 260
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Abstract: Background: Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality and is characterized by episodes of acute exacerbations. Finding a systemic biomarker that reliably predicts outcome after an acute exacerbation remains a major challenge. Heat shock protein 27 (HSP27) has been previously studied in COPD, however, urine excretion trajectory and prognostic value after an exacerbation is unknown. Methods: In this retrospective post hoc analysis of a prospective study that included 253 COPD patients who were hospitalized for acute exacerbation, 207 patients were analyzed. Urine and serum were sampled at admission, discharge, and 180 days after discharge; urine excretion trajectory was analyzed and correlated with clinicopathological and survival data. Results: HSP27 urine excretion increased after an exacerbation episode [1.8% admission, 1.8% discharge, 2.3% 180 days after discharge (P=0.091)]. In severely ill patients (GOLD IV) this course was even more distinct [1.6% admission, 2.1% discharge, 2.8% 180 days after discharge (P=0.007)]. Furthermore, fractional HSP27 urine excretion at discharge was increased in GOLD IV patients (P=0.031). In Kaplan-Meier and univariable Cox proportional hazard models patients with HSP27 urine excretion below 0.845% showed significantly worse survival at 30, 90 and 180 days after discharge. In a multivariable Cox proportional hazard model including established COPD outcome parameters fractional HSP27 urine excretion remained a significant predictor of survival at 30 and 90 days after discharge. Comparing this model to our already published model that includes HSP27 serum concentration we could show that fractional HSP27 urine excretion performs better in short-term survival. Conclusions: Our findings provide novel information about fractional HSP27 urine excretion trajectory in acute exacerbation of COPD. Fractional HSP27 urine excretion may be significantly reduced during an episode of acute exacerbation in COPD patients and may be used as a predictor of short-term all-cause mortality.
Keywords: biomarkers, heat-shock proteins, chronic obstructive pulmonary disease, urine, heat shock protein 27
Published in DiRROS: 25.01.2021; Views: 1643; Downloads: 1134
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