Tumor growth suppression induced by biomimetic silk fibroin hydrogels

Protein-based hydrogels with distinct conformations which enable encapsulation or differentiation of cells are of great interest in 3D cancer research models. Conformational changes may cause macroscopic shifts in the hydrogels, allowing for its use as biosensors and drug carriers. In depth knowledge on how 3D conformational changes in proteins may affect cell fate and tumor formation is required. Thus, this study reports an enzymatically crosslinked silk fibroin (SF) hydrogel system that can undergo intrinsic conformation changes from random coil to β-sheet conformation. In random coil status, the SF hydrogels are transparent, elastic, and present ionic strength and pH stimuli-responses. The random coil hydrogels become β-sheet conformation after 10 days in vitro incubation and 14 days in vivo subcutaneous implantation in rat. When encapsulated with ATDC-5 cells, the random coil SF hydrogel promotes cell survival up to 7 days, whereas the subsequent β-sheet transition induces cell apoptosis in vitro. HeLa cells are further incorporated in SF hydrogels and the constructs are investigated in vitro and in an in vivo chick chorioallantoic membrane model for tumor formation. In vivo, Angiogenesis and tumor formation are suppressed in SF hydrogels. Therefore, these hydrogels provide new insights for cancer research and uses of biomaterials.The authors would like to thank the Portuguese Foundation for Science and Technology (FCT) project grants OsteoCart (PTDC/CTM-BPC/115977/2009) and Tissue2Tissue (PTDC/CTM/105703/2008) which supported this study. Research leading to these results has also received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no REGPOT-CT2012-316331-POLARIS. Le-Ping Yan was awarded a PhD scholarship from FCT (SFRH/BD/64717/2009). We also would like to thank FCT for the distinction attributed to J.M. Oliveira under the Investigador FCT program (IF/00423/2012). The authors also like to acknowledge Dr. Mariana B. Oliveira for technical assistance on the dynamic mechanical analysis of the cell-laden hydrogels

Bioassays- Procedures and Results

Bioassay procedures to describe, evaluate, and predict potential hazard of toxic materials to organisms, ecosystems, and health-related aspects of polluted waters continue to receive widespread attention. However, synthesizing these diverse theoretical, methodological, and procedural entities into an integrated multidisciplinary approach to evaluate environ mental hazards of toxic substances remains difficult. Symposia proceedings pertinent to the toxic substances management in ecosystems have appeared1 and provide an overview of major problems and emerging solutions, including chapters on new bioassay protocols development, and multiple exposure toxicity paradigms. Conclusions and recommendations resulting from a toxicity testing workshop2 discussed current state-of-the-art, identified needed improvements in methodology and research priorities, and called for coordinated multidisciplinary activities regarding physico-chemical, photodegradation, biodegradation, accumulation, and ecotoxicology test protocols. A comprehensive review of test methods for ecotoxicology was prepared by the National Research Council,3 in conjunction with a companion document of working papers prepared for committee use.4 The report was critical of single-species tests to predict ecosystematic effects, and presented detailed discussions of chemical toxicity assessment, factors influencing chemical fate in terrestrial and aquatic ecosystems, relevant properties and processes, appropriate test systems and end points, and a detailed assessment strategy employing integrated use of test systems. Multispecies tests to address eco logical toxicity have been critically reviewed and evaluated,5 including methods for measuring chemical effects on aquatic and terrestrial population interactions and ecosystem properties. A primary conclusion is the need for development and standardization of tests for effects of chemicals on ecological parameters that are indicative of interspecific interactions, community dynamics, and ecosystem function

Bisindolylmaleimide IX: a Novel Anti-SARS-CoV2 Agent Targeting Viral Main Protease 3CLpro Demonstrated by Virtual Screening Pipeline and In-Vitro Validation Assays

SARS-CoV-2, the virus that causes COVID-19 consists of several enzymes with essential functions within its proteome. Here, we focused on repurposing approved and investigational drugs/compounds. We targeted seven proteins with enzymatic activities known to be essential at different stages of the viral cycle including PLpro, 3CLpro, RdRP, Helicase, ExoN, NendoU, and 2′-O-MT. For virtual screening, energy minimization of a crystal structure of the modeled protein was carried out using the Protein Preparation Wizard (Schrodinger LLC 2020-1). Following active site selection based on data mining and COACH predictions, we performed a high-throughput virtual screen of drugs and investigational molecules (n = 5903). The screening was performed against viral targets using three sequential docking modes (i.e., HTVS, SP, and XP). Virtual screening identified ∼290 potential inhibitors based on the criteria of energy, docking parameters, ligand, and binding site strain and score. Drugs specific to each target protein were further analyzed for binding free energy perturbation by molecular mechanics (prime MM-GBSA) and pruning the hits to the top 32 candidates. The top lead from each target pool was further subjected to molecular dynamics simulation using the Desmond module. The resulting top eight hits were tested for their SARS-CoV-2 anti-viral activity in-vitro. Among these, a known inhibitor of protein kinase C isoforms, Bisindolylmaleimide IX (BIM IX), was found to be a potent inhibitor of SARS-CoV-2. Further, target validation through enzymatic assays confirmed 3CLpro to be the target. This is the first study that has showcased BIM IX as a COVID-19 inhibitor thereby validating our pipeline

Wpływ retardantu wzrostu na transpirację i cechy morfologiczne Pelargonium x hortorum L.H. Bailey

Growth retardants may affect some morphological and physiological traits of plants. The aim of the research was to evaluate the influence of a single, flurprimidol spray on transpiration, growth and flowering of geranium. Flurprimidol (Topflor 015 SL) was applied once, as a foliar spray at 7.5, 15.0 or 22.5 mg dm⁻³ . The desirable heights of ‘Classic Noblesse’ and ‘Classic Diabolo’ geraniums were obtained with flurprimidol at concentrations of 22.5 and 15.0 mg dm⁻³ , respectively. Flurprimidol had no influence on stomatal conductance, transpiration rate, the number of days to flower, diminished plant diameter, leaf area, plant fresh and dry mass, inflorescence area index, inflorescence number and increased the inflorescence area to plant height ratio. Chemical name used: α-(1-methylethyl)-α-[4-(trifluromethoxy)phenyl]-5-pyrimidinemethanol (flurprimidol).Retardanty wzrostu mogą wpływać na pewne cechy morfologiczne i fizjologiczne roślin. Celem badań była ocena wpływu fluroprimidolu stosowanego dolistnie i jednokrotnie na transpirację, wzrost i kwitnienie pelargonii. Fluroprimidol (Topflor 015 SL) stosowano dolistnie, jednokrotnie, w stężeniach 7,5, 15,0 lub 22,5 mg dm⁻³ . Żądaną wysokość pelargonii ‘Classic Noblesse’ i ‘Classic Diabolo’ uzyskano, stosując fluroprimidol w stężeniach, odpowiednio, 22,5 i 15,0 mg dm⁻³ . Fluroprimidol nie miał wpływu na przewodność szparkową, transpirację, liczbę dni do kwitnienia, zmniejszył średnicę rośliny, powierzchnię liścia, świeżą i suchą masę rośliny, powierzchnię i liczbę kwiatostanów oraz zwiększył stosunek powierzchni kwiatostanów do wysokości rośliny. Nazwa chemiczna: α-(1-metyloetylo)-α-[4-(trifluorometoksyfenylo]-5-pirymidynometanol fluroprimidol)