Senescence in vitro and ionising radiations—the human diploid fibroblast model

The influence of ionising radiations on ageing is still controversial. Since Hayflick established the concept that diploid cells have finite lifespan in vitro, human diploid fibroblast (HDF) cultures have been recognised as a potent experimental model for cytogerontological investigations. In this study HDF cultures in phase II were exposed to acute irradiation with either X-rays on fast neutrons. The replicative potentials and labelling indices with [3H]thymidine were measured post irradiation until the cultures ceased growth in phase III. Cell mortality was measured by cloning. The apparent loss in replicative potential of irradiated mass cultures was wholly attributable to the loss of viable clonogenic cells. The current concept of precocious clonal senescence in vitro as a late effect of irradiation in clonogenic survivors is not supported by the present experiments. Instead, our results suggest that exposure to a single dose of ionising radiations either causes total replicative incapacitation (killing) of HDF cells and their progeny early after irradiation or leaves their replicative potentials unperturbed

Dessensibilização emocional a estímulos violentos: efeitos numa tarefa de atenção

Classificação de categorias e códigos: 2346 Attention; 2360 Motivation & EmotionO presente estudo teve como objectivo analisar os efeitos imediatos de uma breve exposição a imagens de consequências de violência na subsequente dessensibilização emocional a este tipo de imagens, explorando ainda a hipótese desta dessensibilização emocional se generalizar a imagens de conteúdo positivo (imagens eróticas). Para tal, 61 estudantes universitários foram distribuídos aleatoriamente por duas condições: experimental (visualizaram imagens de consequências de violência – mutilações); controlo (visualizaram imagens de outro conteúdo negativo – ataques, armas). Imediatamente após esta exposição, todos os participantes realizaram uma tarefa de apresentação rápida de estímulos (RSVP) a fim de testar a interferência que imagens de elevado grau de activação emocional (mutilações e eróticas) iriam causar na atenção. Por último, solicitou-se aos participantes que avaliassem um conjunto de imagens sobre cenários da vida real (imagens de mutilações, imagens eróticas e imagens neutras) quanto ao seu grau de activação emocional e à sua valência afectiva através da escala SAM (Self-Assessment Manikin). Os resultados demonstraram, essencialmente, que uma breve exposição a imagens de mutilações foi suficiente para: a) diminuir a capacidade que estímulos de elevado grau de activação emocional assumem na modulação afectiva da atenção; e b) desencadear relatos de menor activação emocional perante todas as categorias de imagens. Estes resultados sugeriram, assim, que uma breve exposição a estímulos de consequências de violência pode contribuir para uma apatia afectiva, e consequentemente, para uma diminuição da reactividade emocional em geral.This study aimed to examine the immediate effects of a brief exposure to pictures of consequences of violence in the subsequent emotional desensitization to such pictures, also exploring the possibility of emotional desensitization to generalize to pictures of positive content (erotic pictures). Thus, 61 students were randomly assigned to two conditions: experimental (viewing pictures of consequences of violence - mutilation); control (viewing pictures of other negative content - attacks, weapons). Immediately after this exposure, all subjects performed a task of rapid stimulus presentation (RSVP) in order to test the interference that strong emotional arousing pictures (mutilation and erotic) would have on attention. Finally, we asked participants to rate a set of pictures of real-life scenarios (pictures of mutilation, erotic pictures and neutral pictures) in their degree of emotional arousal and affective valence using SAM (the Self-Assessment Manikin scale). Overall, the results showed that a brief exposure to pictures of mutilation was enough to: a) reduce the ability that strong arousing stimuli take on affective modulation of attention; and b) produce reports of lower emotional arousal across all picture type. Therefore, these results suggested that a brief exposure to stimuli of consequences of violence can contribute to an emotional apathy, and consequently to a decrease in emotional reactivity in general

Ageing profiling of craft beers: a sensorial and chemical overview

One of the main differences between craft and commercial beers is the presence of active yeast in the bottle, which can have high impact on beer stability during shelflife. For this reason, sensory and chemical beer profiling during storage is of upmost importance when focusing quality control. This study investigated the changes that occur during the storage/ageing of four different craft beers and two commercial beers, which were used for comparison. Sensory analysis of capped and corked beers was performed overtime accompanied by sampling for minor volatiles analysis. Craft beers showed an aromatic profile more intense than the commercial beers and kept the profile similar after six months, as well as the commercial beers. Fruity, floral and caramel were among the main descriptors found for the beers studied, and maintained their intensity during the analysis time. Minor compounds analysis was coherent with the aromatic profiles obtained, as well as those portrayed in the literature, however most of the main ageing markers reported were not found in the beers studied. Among the minor volatiles studied esters concentration varied differently depending on beer type and alcohols, fatty acids, carbonyl compounds and pyrazines concentrations increased for all beers. However, variations on minor volatiles composition had low impact on sensorial perception. The results allowed to conclude that the craft beers maintained the sensory quality as a commercial beer, over a six month period, with the benefit of having more intense flavors and aromas when compared to the commercial beers studied.info:eu-repo/semantics/publishedVersio

Avaliação do uso do solo e dos recursos florestais no semiárido do estado da Paraíba

The use of soil and forest resources of the Caatinga biome in the state of Paraíbawas evaluated from 1996 to 2018. Data on vegetation cover and forest resource characteristics and their productive potential for firewood and charcoal were collected.The information used to characterize Paraíba’s land use and forest resources were examined by the Brazilian Institute of Geography and Statistics (IBGE), the Ministry of Environment of Brazilian (MMA) and the Northeast Plants Association (APNE). The research is exploratory and based on secondary data and may contribute, in part, to the economic development in the state. The results point to the existence of a constant degradation of the vegetation cover, although the types of soil use have changed over the studied years. The estimates adopted for vegetation cover and land use in Paraíba showed sensitivity and a high degree of risk to desertification of the biome, requiring permanent joint actions that guarantee the sustainable use of its biodiversity. It is concluded that the effective solution comes from the awareness and the practice of the Sustainable Forest Management Plan in the semi-arid region of Paraíba, providing more effectively the sustainability of the Caatinga biome.Avaliou-se o uso do solo e dos recursos florestais do bioma Caatinga no estado da Paraíba, de 1996 a 2018. Foram levantados dados da cobertura vegetal e das características dos recursos florestais e o seu potencial produtivo para a lenha e o carvão vegetal. As informações empregadas para caracterização do uso do solo e dos recursos florestais da Paraíba foram obtidas do Instituto Brasileiro de Geografia e Estatística (IBGE), do Ministério do Meio Ambiente (MMA) e da Associação Plantas do Nordeste (APNE). A pesquisa foi exploratória e os resultados apontam a existência de uma degradação contínua da cobertura vegetal, porém os tipos de uso do solo se modificaram ao longo dos anos estudados. Observou-se uma alteração no uso das terras da Paraíba com uma ampliação das áreas de matas/florestas e redução das áreas de pastagem. O carvão vegetal e a lenha foram os principais produtos do extrativismo. A Caatinga paraibana perdeu mais de 46% da sua vegetação, cerca de 2,40 milhões de hectares, mas observou-se o aumento do PMFS via adoção de políticas públicas e conscientização do mercado. As estimativas adotadas da cobertura vegetal e do uso do solo da Paraíba mostraram sensibilidade e elevado grau de risco à desertificação do bioma, necessitando de ações conjuntas permanentes que garantam o uso sustentável da biodiversidade. Concluise que a solução efetiva vem da conscientização e da prática do Plano de Manejo Florestal Sustentado no semiárido paraibano, proporcionando de forma mais eficaz a sustentabilidade do bioma Caatinga.

Agent based modelling helps in understanding the rules by which fibroblasts support keratinocyte colony formation

Background: Autologous keratincoytes are routinely expanded using irradiated mouse fibroblasts and bovine serum for clinical use. With growing concerns about the safety of these xenobiotic materials, it is desirable to culture keratinocytes in media without animal derived products. An improved understanding of epithelial/mesenchymal interactions could assist in this. Methodology/Principal Findings: A keratincyte/fibroblast o-culture model was developed by extending an agent-based keratinocyte colony formation model to include the response of keratinocytes to both fibroblasts and serum. The model was validated by comparison of the in virtuo and in vitro multicellular behaviour of keratinocytes and fibroblasts in single and co-culture in Greens medium. To test the robustness of the model, several properties of the fibroblasts were changed to investigate their influence on the multicellular morphogenesis of keratinocyes and fibroblasts. The model was then used to generate hypotheses to explore the interactions of both proliferative and growth arrested fibroblasts with keratinocytes. The key predictions arising from the model which were confirmed by in vitro experiments were that 1) the ratio of fibroblasts to keratinocytes would critically influence keratinocyte colony expansion, 2) this ratio needed to be optimum at the beginning of the co-culture, 3) proliferative fibroblasts would be more effective than irradiated cells in expanding keratinocytes and 4) in the presence of an adequate number of fibroblasts, keratinocyte expansion would be independent of serum. Conclusions: A closely associated computational and biological approach is a powerful tool for understanding complex biological systems such as the interactions between keratinocytes and fibroblasts. The key outcome of this study is the finding that the early addition of a critical ratio of proliferative fibroblasts can give rapid keratinocyte expansion without the use of irradiated mouse fibroblasts and bovine serum

Volatile fingerprinting differentiates diverse-aged craft beers

Supplementary data to this article can be found online at https:// doi.org/10.1016/j.lwt.2019.03.044.Beer ageing on wood is a complex and difficult to control process involving several reactions and compounds. Difficulties in understanding the underlying phenomena often lead to empirical and unpredictable processes and heterogeneous products. This work resorts to volatile fingerprinting along with multivariate analysis as tools to differentiate and highlight differences in beers derived from diverse production processes. Volatile composition of beers originating from barrel ageing processes and unaged beer were analyzed by GC-MS. The collected data was processed by principal component analysis, which allowed the evaluation of relations between samples and volatile compounds. Beers were distinguished by clusters comprising different groups of volatiles. Beer with the longest period in barrel was in the cluster with the most volatiles. Beer produced by resident barrel microbiota fermentation was characterized by presence of Brettanomyces sp. metabolites. Beer aged in barrel by a shorter time period showed characteristic content of ethyl esters and oak extractives. Beer produced in inox vat and beer fermented in barrel with pitching of S. cerevisiae appeared in the same cluster, relating with fermentative esters. Volatile fingerprinting was a viable approach to characterize and distinguish the analyzed beers, providing relevant information regarding the impact of production methodologies in volatile composition.This work had funding support of the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2019 unit and COMPETE 2020 (POCI-01-0145 FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte. Fermentum –EngenhariadasFermentações Lda.also participated incofunding and supplying materials for this work. Authors would like to thank Mr. Paulo Coutinho and Quinta do Portal for supplying the oak barrels used in this work.info:eu-repo/semantics/publishedVersio

Dynamic assembly of chromatin complexes during cellular senescence: implications for the growth arrest of human melanocytic nevi

The retinoblastoma (RB)/p16INK4a pathway regulates senescence of human melanocytes in culture and oncogene-induced senescence of melanocytic nevi in vivo. This senescence response is likely due to chromatin modifications because RB complexes from senescent melanocytes contain increased levels of histone deacetylase (HDAC) activity and tethered HDAC1. Here we show that HDAC1 is prominently detected in p16INK4a-positive, senescent intradermal melanocytic nevi but not in proliferating, recurrent nevus cells that localize to the epidermal/dermal junction. To assess the role of HDAC1 in the senescence of melanocytes and nevi, we used tetracycline-based inducible expression systems in cultured melanocytic cells. We found that HDAC1 drives a sequential and cooperative activity of chromatin remodeling effectors, including transient recruitment of Brahma (Brm1) into RB/HDAC1 mega-complexes, formation of heterochromatin protein 1β (HP1β)/SUV39H1 foci, methylation of H3-K9, stable association of RB with chromatin and significant global heterochromatinization. These chromatin changes coincide with expression of typical markers of senescence, including the senescent-associated β-galactosidase marker. Notably, formation of RB/HP1β foci and early tethering of RB to chromatin depends on intact Brm1 ATPase activity. As cells reached senescence, ejection of Brm1 from chromatin coincided with its dissociation from HP1β/RB and relocalization to protein complexes of lower molecular weight. These results provide new insights into the role of the RB pathway in regulating cellular senescence and implicate HDAC1 as a likely mediator of early chromatin remodeling events

Insulin and hydrocortisone influences on cultured rat tongue epithelium

Rat tongue epithelium was separated from underlying connective tissue by trypsinization, dispersed into single cells and small clusters and plated on cellulose acetate-nitrate filters, collagen gels or plastic substrate in serum-supplemented media. Morphologically, abundance of growth and stratification of epithelium was greatest on floating collagen gels, intermediate on plastic and least on the filters. Cultures on the plastic substrate were used to test the effects of insulin, hydrocortisone, dimethyl sulphoxide, glucose and soybean trypsin inhibitor upon epithelial outgrowth. Cultures were plated at the same density, grown to partial con-fluency, and analysed with a superimposed point lattice to determine the fraction of total subsurface covered. Cells cultured 1.25 - 5 x 105 cells/cm2 in serum-supplemented [alpha]MEM or McCoy's 5A media produced the best outgrowth. Additional insulin supplementation at 40 [mu]g/ml gave better outgrowth than 400 or 4 [mu]g/ml within the first week. Insulin at 40 [mu]g/ml also gave better outgrowth than a mixed insulin-hydrocortisone supplement at three different levels or than hydrocortisone supplement alone at three different levels. When 0.5 per cent DMSO was added to any of these supplementary formulas, epithelial outgrowth was reduced compared with the same formulae without DMSO. Addition of three times the formula level of glucose also reduced epithelial outgrowth. Addition of soybean trypsin inhibitor to [alpha]MEM supplemented with insulin, but not fetal calf serum, caused increased epithelial outgrowth. These findings helped define appropriate conditions for cell attachment, migration, proliferation and differentiation of primary rat tongue epithelial cultures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23749/1/0000722.pd