Fat mimetic capacity of Chlorella vulgaris biomass in oil-in-water food emulsions stabilized by pea protein

Vegetable proteins proved to be good emulsifiers for food emulsions with dietetic advantages. The use of these emulsions as car- riers for healthy ingredients, such as colourings, with antioxidant and other beneficial properties, is an interesting subject. In this work, the capacity of the biomass of the microalga Chlorella vulgaris (which has been widely used as a food supplement) as a fat mimetic, and its emulsifier ability, was evaluated. Pea protein emulsions with C. vulgaris addition (both green and orange – carotenogenic) were prepared at different protein and oil contents. The rheological properties of the respective food emulsions were measured in terms of the viscoelastic properties and steady state flow behaviour and texture properties. It was observed that the two microalgal forms evidenced a fat mimetic capacity in these emulsions, the performance of the green stage of this C. vulgaris organism was significantly (p < 0.05) better than the orange stage

Influence of landscape features and management practices in olive groves for optimized pest control

Trabalho apresentado em XI European Congress Of Entomology, 2-6 July 2018, Nápoles, Itália.N/

Spiders actively choose and feed on nutritious non-prey food resources

Spiders are generalist predators adapted to consume a wide range of prey although their ability to exploit non-prey foods such as pollen, nectar, and honeydew has been referred but less studied. In this work, we investigated the effect of different non-prey food items (Glucose at 0.5 M; aphid honeydew; black scale honeydew; a mixture of glucose 0.5 M, phenylalanine 0.1 mM, proline 0.1 mM, and tryptophan 0.1 mM; honey at 10%, and pollen at 10%) on the survival of immature spiders of two functional groups represented by Haplodrassus rufipes (ground hunters) and Synema globosum (ambushers), and their feeding choices, in laboratory experiments. The overall survival of both species fed on non-prey foods significantly increased compared to individuals fed on water. The black-scale honeydew was the best food for H. rufipes increasing longevity up to 117 days. The highest survival reached by S. globosum was observed when fed on a mixture of glucose 0.5 M and three amino acids. When different non-prey food items were offered together, the exploring rate was significantly higher for H. rufipes than for S. globosum. H. rufipes chose to feed on honey whereas S. globosum chose the mixture treatment. The most chosen food items corresponded with those that provided the highest longevities in both species. Our results suggest that spiders could search, recognize and actively select the most beneficial non-prey food. Habitat management practices such as maintaining weed strips in the crop may provide these valuable supplementary food resources within agroecosystems contributing for biological pest control.info:eu-repo/semantics/publishedVersio

Functional responses of three guilds of spiders: Comparing single- and multiprey approaches

Spiders are successful natural enemies of pests occurring throughout the different strata of an agroecosystem. The study of their functional responses can provide information related to the potential effectiveness of different species and guilds on reducing a pest population. However, multiple prey availability may change the functional response of a predator. In this study, the functional responses of three species of spiders in single-prey and multiple-prey experiments were modelled. The spider species Haplodrassus rufipes, Araniella cucurbitina and Synema globosum were chosen as being representatives of ground runners, orb-weavers and ambushers, respectively. Three prey species were selected: a target prey, the Mediterranean fruit fly Ceratitis capitata and two alternate prey species, the flour moth Ephestia kuehniella and the house cricket Acheta domesticus. When the selected target prey C. capitata was supplied in the single-prey experiments, the most and the least efficient spider species were H. rufipes and S. globosum, respectively. However, opposite results were obtained when alternative preys were supplied. Also, A. cucurbitina significantly changed its functional response with the presence of alternative prey species. Considering the prey preference during the multiple-prey experiments, A. domesticus, used as representative of a heavy, long-sized and highly motile prey, was avoided whereas C. capitata, the target pest used as representative of light, small-sized and moderately motile prey was preferred by the three species of spiders. Ephestia kuehniella, used as representative of light, medium-sized and low motile prey was occasionally consumed. Each guild could include efficient predators against pests according to its hunting strategies and the ecological exploited niches. Orb-weavers could be efficient predators against flying pests; ambushers such as S. globosum could contribute to the reduction of the populations of flower-visiting pests, whereas active ground hunters may also play an important role preying on pests that develop a part or all of its life cycle in the ground. However, further research on feeding behaviour such as prey switching is needed for a better understanding of the effectiveness of spiders as natural enemies.This work was funded by Portuguese Foundation for Science and Technology (FCT) through the project EXCL/AGR-PRO/0591/2012 “Olive crop protection in sustainable production under global climatic changes: linking ecological infrastructures to ecosystem functions” and by the project ReNATURE – Valorization of the Natural Endogenous Resources of the Centro Region” funded by Centro 2020 (Centro-01-0145-FEDER-000007). Jacinto Benhadi-Marín is grateful to the Portuguese Foundation of Science and Technology for financial support through the Ph.D. grant SFRH/BD/97248/2013. This manuscript is part of Jacinto Benhadi-Marín's Ph.D. thesis.info:eu-repo/semantics/publishedVersio

EcoPred: an educational individual based model to explain biological control, a case study within an arable land

Individual based models (IBMs) are up-to-date tools both in research and educational areas. Here we introduce an IBM built on NetLogo platform that simulates a top-down trophic cascade controlled by the pressure exerted by two model predators (web-building spiders and ground runner spiders) on a model pest (the olive fruit fly) within a hypothetical agricultural landscape (the olive crop). EcoPred is an IBM that aims to be an educational tool that can help teachers to explain concepts related to ecology in a modern, enjoyable and comprehensive way. EcoPred reflects the changes on a fly population within a simulated olive crop according to (1) the mortality rate caused by the predation of two spider species and energy loss, (2) the energy gain by feeding on flowers and (3) the reproduction rate in olive trees. The model was tested with 26 students achieving very good results in terms of acceptance and interest on the learning method. EcoPred can be used for educational purposes with 16 year old students and older to explain ecological concepts such as trophic level, species interactions, limiting factor and biological control in an interactive way simultaneously introducing students to biology oriented programming languages.This work was supported by the Portuguese Foundation of Science and Technology [PTDC/AGR-PRO/111123/200, SFRH/BD/97248/2013; Centro 2020 [Centro-01-0145-FEDER-000007].info:eu-repo/semantics/publishedVersio

Distribution of the spider community in the olive grove agroecosystem (Portugal): potential bioindicators

Spiders are successful natural enemies in different crops. Research on the role of spiders as natural enemies within agroecosystems needs to address the distribution of their communities across different spatial scales, as well as the dominant species. We studied the spatial distribution of the community of spiders of the olive agroecosystem in Northeastern Portugal and investigated potential species that could be used as bioindicators of agricultural management in the olive grove. We found nine functional groups (ambushers, foliage runner hunters, ground hunters, orb-web builders, sheet web builders, sensing web-builders, space web builders, stalkers and wandering sheet/tangle weavers) encompassing a community that changed significantly across the horizontal and vertical gradient. We propose Thanatus vulgaris Simon, 1870 as potential bioindicator for the ground of the olive grove central area and Ozyptila pauxilla (Simon, 1870) for the ground of the olive grove peripheral area. Adjacent shrubland areas could play an important role in biological control of pests, allowing the exchange of species and individuals with the olive crop. The role of agrobiont species as indicators of agricultural managements deserves further investigation towards the enhancement of the effectiveness of spiders within low-impact crop management in arable landscapes.Thisworkwas funded byCentro 2020 (Centro-01-0145-FEDER- 000007) through the project ‘ReNATURE – Valorization of the Natural Endogenous Resources of the Centro Region’. The authors are indebted to all of the farmers who allowed access to their olive groves. Jacinto Benhadi-Marín is grateful to the Portuguese Foundation of Science and Technology (FCT) for financial support through the PhD grant SFRH/BD/97248/2013. This manuscript is part of Jacinto Benhadi-Marín’s PhD thesis. The authors declare that they have no conflicts of interest.info:eu-repo/semantics/publishedVersio

Increase in ghrelin levels after weight loss in obese Zucker rats is prevented by gastric banding.

Obes Surg. 2007 Dec;17(12):1599-607. Epub 2007 Nov 30. Increase in ghrelin levels after weight loss in obese Zucker rats is prevented by gastric banding. Monteiro MP, Ribeiro AH, Nunes AF, Sousa MM, Monteiro JD, Aguas AP, Cardoso MH. Department of Anatomy and UMIB (Unit for Multidisciplinary Biomedical Research) of ICBAS (Abel Salazar Institute for the Biomedical Sciences), University of Porto, 4099-003 Porto, Portugal. [email protected] Abstract BACKGROUND: Gastric banding is thought to decrease appetite in addition to the mechanical effects of food restriction, although this has been difficult to demonstrate in human studies. Our aim was to investigate the changes in orexigenic signals in the obese Zucker rat after gastric banding. METHODS: Obese Zucker rats (fa/fa) were submitted to gastric banding (GBP), sham gastric banding fed ad libitum (sham), or sham operation with food restriction, pair-fed to the gastric banding group (sham-PF). Lean Zucker rats (fa/+) were used as additional controls. Body weight and food intake were daily recorded for 21 days after surgery when epididymal fat was weighed and fasting ghrelin and hypothalamic NPY mRNA expression were measured. RESULTS: Gastric banding in obese Zucker rats resulted in a significant decrease of cumulative body weight gain and food intake. Furthermore, gastric banded rats were leaner than Sham-PF, as expressed by a significantly lower epididymal fat weight. Ghrelin levels of gastric banded rats were not increased when compared to sham-operated animals fed ad libitum and were significantly lower than the levels of weight matched sham-PF rats (1116.9 +/- 103.3 g GBP vs 963.2 +/- 54.3 g sham, 3,079.5 +/- 221.6 sham-PF and 2,969.9 +/- 150.9 g lean rats, p < 0.001); hypothalamic NPY mRNA expression was not increased in GBP when compared to sham-operated rats. CONCLUSION: In obese Zucker rats, GBP prevents the increase in orexigenic signals that occur during caloric deprivation. Our data support the hypothesis that sustained weight loss observed after gastric banding does not depend solely on food restriction

A simulation-based method to compare the pest suppression potential of predators: A case study with spiders

Assessing and comparing the pest killing capacity of predators is a crucial but laborious task during the implementation of sustainable farming systems. Critical attributes of assessment include quantifying predator’s attack rate (a) and handling time (Th). The maximum attack rate (T/Th) (i.e. the maximum number of prey that can be attacked by a predator during the time interval (T) considered) could be a more precise and interpretable indicator of the potential suppression of pests exerted by a predator; however, its calculation only provides a point estimator usually derived from incomplete datasets (e.g. unbalanced or low replicated experimental designs) that could lead to draw wrong conclusions. We introduce simaR (simulation of maximum attack rates using R), an R library that generates 95% confidence intervals around estimates of the maximum attack rate that can be easily and intuitively used to compare across species. We validated the simulation method and used the empirical results of a controlled laboratory experiment to compare the maximum attack rates of spiders across a range of Medfly prey densities and illustrate how to use simaR with non-replicated partial data. Applying our method we found a significant effect of temperature on the maximum attack rate of two different guilds of spiders, the orb-weaver A. cucurbitina and the ambusher S. globosum that was not relevant regarding their attack rate and handling time. Our method compares different predator species and/or experimental conditions in a simple and reproducible procedure through an accurate, easy-to-use, fast and statistically robust analysis, based on simulation and bootstrapping, that can be used to assess the pest suppression potential of predators by simulating their functional responses from low-effort laboratory trials.The authors are grateful to the Portuguese Foundation for Science and Technology for financial support through the project EXCL/AGRPRO/ 0591/2012 “Olive crop protection in sustainable production under global climatic changes: linking ecological infrastructures to ecosystem functions”. Jacinto Benhadi-Marín thanks FCT for the Ph.D. grant SFRH/BD/97248/2013. This manuscript is part of Jacinto Benhadi-Marín’s Ph.D. thesis. The authors would like to thank the editor and reviewers for their valuable comments and have no conflicts of interest to declare.info:eu-repo/semantics/publishedVersio

Collembolan morphospecies (Hexapoda: Collembola) in serpentine soils: a case study in a natural ecosystem in northeastern Portugal

Serpentine soils represent challenging habitats for plants and soil dwelling organisms, such as collembolans, because they typically exhibit high levels of heavy metals (e.g. chromium, cobalt, and nickel). Serpentinized areas cover about 8000 ha in Northeastern Portugal. While the plant communities are well studied, the collembolans are virtually unknown. The data presented here represent the first effort to describe the structure of a collembolan community, using morphospecies as a surrogate of species, in a serpentinized area occupied by a natural forest of Quercus rotundifolia and Quercus faginea located nearby Bragança (Portugal). Sampling was performed during the last week of September of 2008 in a serpentinized area near Bragança (Portugal). At each of the 29 sampling points (distributed along two transects) collembolans were collected with a soil core (5 cm diameter x 10 cm depth). The collembolans were extracted from the soil (using a McFadyen apparatus), sorted, counted and finally identified to morphospecies level. The number of morphospecies observed was 37. The total abundance in the mineral horizon (1862 individuals) was not significantly different from the organic horizon (1883 individuals). The Simpson Diversity Index and Richness were higher in the organic horizon (21.7 and 35 species, respectively) than in the mineral horizon (9.9 and 30 species, respectively). The species accumulation curves showed that the estimated number of morphospecies for the mineral horizon is 36 while for the organic horizon is 38

Variação espacial de propriedades físicas e químicas do solo em olivais de Trás-os-Montes

A introdução de novos sistemas de gestão da vegetação herbácea em olivais de Trás-os-Montes tem realçado o interesse em conhecer os efeitos produzidos na variabilidade espacial das propriedades do solo. Com o presente trabalho pretende-se avaliar o efeito de diferentes sistemas de gestão do coberto vegetal herbáceo em olivais na distribuição espacial de propriedades físicas e químicas do solo. O estudo decorreu em nove olivais com os seguintes sistemas de gestão do solo: (MT) solo nu ao longo de todo o ano, com recurso à mobilização tradicional; (HB) cobertura do solo por vegetação natural, com controlo efetuado por aplicação de herbicidas na linha de plantação (LP) e destroçamento da vegetação seca na entrelinha (EL); (LS) cobertura do solo por espécies de leguminosas semeadas, com controlo efetuado por pastoreio e posterior destroçamento da vegetação seca e (VN) cobertura do solo por vegetação natural. Em cada olival foram selecionados 16 locais (8 na LP e 8 na EL), onde se procedeu à colheita de amostras de solo perturbadas e não perturbadas na profundidade 0-5 cm. Foram determinados vários parâmetros físicos e químicos do solo e calculou-se índices de enriquecimento (IE). Os olivais que utilizam coberturas vivas apresentam acumulação de resíduos orgânicos à superfície, sendo esta sempre superior na LP, o que conduz a teores de matéria orgânica superiores e com distribuição espacial mais homogénea comparativamente aos olivais mobilizados. Em concordância com esta observação, a densidade aparente é menor na LP apresentando variabilidade espacial inferior nos olivais com leguminosas semeadas. Os nutrientes do solo não apresentam uma tendência consistente com o sistema de gestão do solo, mas de um modo geral, os olivais com coberto de leguminosas tendem a apresentar maior homogeneidade espacial.The introduction of management systems for the herbaceous vegetation in olive grove from Trás-os-Montes has been stressing the interest for the knowledge about the effects caused to the spatial variability of soil properties. The objective of this work is to evaluate the effect of different management systems of herbaceous ground covers in the different spatial physical and chemical soil properties of the olive grove. The study took place in nine olive groves that have been managed with the following systems: (1) naked soil due to mobilization; (2) soil covered by natural vegetation controlled by herbicides on the plantation row and dried vegetation broken into pieces on the row between the trees; (3) soil covered by sown leguminous, controlled by grazing and (4) soil covered by natural vegetation. In each olive grove, 16 places (eight in the plantation row and eight in the row between the trees) were selected and disturbed and undisturbed soil samples were collected at 0-5 cm depth. Several physical and chemical soil parameters were calculated as well as the enrichment index (IE). Results showed that the olive groves with soil covers accumulated organic materials on the surface, reaching higher values in the plantation row, and producing higher levels of organic matter with more homogeneous spatial distribution when compared with mobilized groves. In agreement with this observation, the apparent density is lower in the plantation row showing an inferior spatial variability in the olive groves covered by sown leguminous. Soil nutrients did not show a consistent trend with the soil management system but, in a general way, the olive groves covered by sown leguminous had a tendency to present higher spatial homogeneity