CRISP (crayfish and rice integrated system of production): 2. Modelling crayfish (Procambarus clarkii) population dynamics

An ecological sub-model of crayfish (Procambarus clarkii) population dynamics is presented for integration into the CRISP (crayfish and rice integrated system of production) series of models. The present structure is directed towards simulation of crayfish population responses under different human interventions, namely different capture rates. The crayfish population was subdivided into seven age classes of 80 days, each one constituting a state variable. The increase in weight for each 80-day period was considered dependent on the temperature, the oxygen level and the water level. Mortality was assumed to be dependent on the dry weight of the crayfish and regulated by the total crayfish biomass. Food, water and oxygen content of the water were considered to be non limiting. Total crayfish biomass and total wet weight of crayfish captures were very sensitive to both the temperature for maximum growth and the mortality rates. Our most optimistic simulation, with a 50% decrease in the mortality rates, resulted in a fourfold increase in captures, from 230 to 917 kg ha-1 per year. Without capture, a value of 121 kg ha-1 was simulated for the average crayfish biomass, which is close to the 124 kg ha-1 obtained with crayfish capture. Our simulated average crayfish biomass was approximately 120 kg ha-1 in a natural situation, which lies inside the reported ranges from areas at approximately the same latitude.http://www.sciencedirect.com/science/article/B6VBS-3XM2SN8-2/1/c3c8d93a43ea0ffd5fc0055b9347934

Influence of human biology and health (hbh) teaching–learning process on students’ conceptions of the covid-19 vaccine

The COVID‐19 pandemic created the need for universal vaccination. This study aimed to compare university students’ (pre‐service teachers) conceptions who had already learned the im‐ mune system and vaccination topics in the “Human Biology and Health (HBH)” curricular unit with those who had not yet taken part in it. It also intended to verify the influence of secondary school background, perception of one’s own health, feeling at risk for COVID‐19 and their own experience with it and scientific knowledge related to SARS‐CoV‐2 vaccination. It was a cross‐sectional study with a mixed methodology for data analysis. A questionnaire was applied online to a sample of 102 university students. Results show that students who had already taken the subject on the immune system and vaccination had more acceptable conceptions about the vaccine and wanted to be vac‐ cinated but not in the initial moment of the national vaccination process. The fear of adverse reac‐ tions seemed to be the major hesitancy factor. Furthermore, students’ argumentation showed that their conceptions progressed towards more socio‐scientific reasoning.info:eu-repo/semantics/publishedVersio

Gastrointestinal parasitism in Miranda donkeys : epidemiology and selective control of strongyles infection in the Northeast of Portugal

Research Areas: Agriculture ; Veterinary Sciences ; ZoologyIn Portugal, equine parasitism in pasture animals is characterized by high parasitic burden and high helminthic biodiversity; both factors are potentially pathogenic for their hosts. The decrease in the number of donkeys over the last years in Portugal, their importance in rural lowland and mountain ecosystems and pastures and the scarce information regarding their parasitism led to this research, which aimed to evaluate the parasitological status of a Miranda donkey breed population, a native breed mainly located in the northeast of Portugal. This study provides better knowledge of their gastrointestinal parasitism, particularly strongyles, and the assessment of a targeted selective treatment (TST) as an alternative control approach of their parasitism. A longitudinal observational study was developed during a period of five years in a population of 62 Miranda donkeys. At first, strategic deworming of these animals was performed every semester, but this was progressively replaced by a TST approach according to the levels of Eggs per Gram (EPG). This new deworming strategy was conducted in association with a regular parasitological monitoring of the animals every three months, being dewormed with ivermectin when egg shedding was higher than 500 EPG. Over the study period, a decrease of the annual prevalence rate of infection by gastrointestinal strongyles was observed, from 35.5% to 19.4%, as well as a negative binomial distribution of parasitic strongyles in donkeys submitted to selective anthelminthic control. The prevalence rate of infection was higher in females (39.5%), in individuals under four years (46.7%) and in those presenting a lower body condition (40.8%). The egg output was higher in animals younger than four years (589.3 EPG) than in those older than 10 years (533.6 EPG) (p < 0.05). However, no differences were observed according to sex during the study period. Results from this study allowed to note the influence of swampy pastures and of the weather changes in the epidemiology of strongylosis in Miranda donkeys. Moreover, it was possible to establish the annual epidemiological curve of strongyle egg shedding, with June being the month with the highest EPG, December having the lowest EPG and March and September showing intermediate numbers. Overall, a lower biodiversity of gastrointestinal parasites was observed. Cyathostomum sensu lato was the most prevalent genus and Strongylus vulgaris was the most observed large strongyle of the Strongylidae family. Trichostrongylus axei and Parascaris sp. were other nematodes with a minor frequency. The higher prevalence of strongyles at the beginning of the study showed a progressive decrease throughout the research period, and also for parasite biodiversity. Therefore, a targeted selective treatment seems to be a rational anthelminthic control approach in Miranda donkey strongyle infection and in other gastrointestinal parasites, since it reduces the antiparasitic treatments, the parasite’ prevalence and the EPG level. However, a loss of parasite biodiversity was noted at the end of the study period, as Cyathostominae were the only isolated strongyles. This can be a challenging situation in the long run, taking the ability of these nematodes to adapt easily to any deworming program, meaning that fecal EPG monitoring should be kept as a rule to a rational parasite control program.info:eu-repo/semantics/publishedVersio

Assessing the intestinal permeability and anti-inflammatory potential of sesquiterpene lactones from chicory

Funding: This research and the article processing cost were funded by EU Horizon 2020 research & innovation programme under grant agreement N. 760891 project CHIC. M.S.M. also acknowledges the financial support from Fundação para a Ciência e Tecnologia for her PhD scholarship (SFRD/BD/145551/2019).Cichorium intybus L. has recently gained major attention due to large quantities of health-promoting compounds in its roots, such as inulin and sesquiterpene lactones (SLs). Chicory is the main dietary source of SLs, which have underexplored bioactive potential. In this study, we assessed the capacity of SLs to permeate the intestinal barrier to become physiologically available, using in silico predictions and in vitro studies with the well-established cell model of the human intestinal mucosa (differentiated Caco-2 cells). The potential of SLs to modulate inflammatory responses through modulation of the nuclear factor of activated T-cells (NFAT) pathway was also evaluated, using a yeast reporter system. Lactucopicrin was revealed as the most permeable chicory SL in the intestinal barrier model, but it had low anti-inflammatory potential. The SL with the highest anti-inflammatory potential was 11β,13-dihydrolactucin, which inhibited up to 54% of Calcineurin-responsive zinc finger (Crz1) activation, concomitantly with the impairment of the nuclear accumulation of Crz1, the yeast orthologue of human NFAT.publishersversionpublishe

Produção de uma xilanase fúngica por Komagataella phaffii em biorreator.

As xilanases são enzimas que hidrolisam ligações Beta-14 presentes na hemicelulose que compõe a parede celular vegetal. Essas enzimas são produzidas por bactérias, fungos e plantas. Por apresentarem diversas aplicações, como na fabricação de pães, na indústria farmacêutica, na fabricação de celulose e na geração de biocombustíveis, o objetivo desse trabalho foi escalonar a produção de uma xilanase de origem fúngica (F43 GH 10-03) por Komagataella phaffii em biorreatores para futura aplicação biotecnológica. Os cultivos foram realizados com fluxo de ar entre 0,1 a 4,0 vvm, pO2 fixado em 25%, os inóculos com densidade ótica a 600 nm iniciais fixadas em 2, 4 e 6 e temperatura de 30°C. Após fase de crescimento celular, foi estabelecida uma alimentação com glicose 50% (m/v) (fluxo de 4 g/L/h). Incialmente, a xilanase foi produzida em frascos apresentando atividade de 1,5 UI/mL entre 24 a 72 h de cultivo. A produção da xilanase em biorreator realizada em três condições com DO600 inicial fixada em 2, 4 e 6 mostrou que todos os cultivos apresentaram atividade de xilanase a partir de 14,5 h, com secreção de xilanase ascendente, com atividade variando entre 12 e 23 UI/mL, e a DO600 variando entre 197 e 234, com produção de proteínas totais entre 0,26 e 0,48 g/L. A análise por eletroforese mostrou uma banda de 55 kDa correspondendo à xilanase F43 GH 10-03. Dos três cultivos realizados, a estratégia com DO600 inicial fixada em 4 apresentou a maior atividade específica (70,7 UI/mg de proteína). Essa condição pode ser utilizada para o início de estudos de otimização de produção dessa enzima em biorreator