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2.
Biota Neotrop. (Online, Ed. ingl.) ; 21(3): e20201034, 2021. tab, graf
Article in English | LILACS-Express | LILACS | ID: biblio-1278410

ABSTRACT

Abstract The use and occupation of land by human population substantially influence environmental variables and fish assemblage in streams. However, there is little knowledge on how these changes affect the ecomorphological structure of fish assemblage in mesohabitats. Therefore, we aim to assess whether the land-use types affect the ecomorphological structure of fish assemblage in distinct mesohabitats. Environmental and ichthyofaunistic data were collected in three mesohabitats (rifles, runs, and pools) of five rural and five urban streams. Twenty-one ecomorphological indices were obtained from the mean of linear morphological measurements and areas of the fishes. Subsequently, the Euclidean distance was calculated, based on the ecomorphological indices, between each pair of species, to measure the ecomorphological distances for the mesohabitats of the rural and urban streams. The results show that the urban environment is more harmful to streams than the rural one, due to changes in the environmental variables and decrease in species richness. The main environmental changes found in urban streams were the decrease in canopy cover by riparian vegetation and dissolved oxygen, and the increase in electrical conductivity and bed silting. Also, there was a significant decrease in the morphological similarity between fish species in the mesohabitats of urban streams compared to rural ones. Therefore, we can conclude that the urban environment leads to the loss of morphologically similar fish species in the mesohabitats, with only a few functionally distinct species remaining.


Resumo O uso e ocupação do solo pela população humana influencia substancialmente as variáveis ambientais e a assembleia de peixes em riachos. No entanto, há pouco conhecimento de como estas alterações afeta a estrutura ecomorfológica da assembleia de peixes em mesohábitats. Portanto, objetiva-se avaliar se o tipo do uso do solo afeta a estrutura ecomorfológica da assembleia de peixes nos distintos mesohábitats. Dados ambientais e ictiofaunísticos foram coletados em três mesohabitats (corredeiras, rápidos e remansos) de cinco riachos rurais e cinco urbanos. Vinte e um índices ecomorfológicos foram obtidos a partir das médias das medidas morfológicas lineares e áreas dos peixes. Posteriormente, a distância Euclidiana foi calculada, baseada nos índices ecomorfológicos, entre cada par de espécies, afim de mensurar as distâncias ecomorfológicas para os mesohábitats dos riachos rurais e urbanos. Os resultados mostram que o ambiente urbano é mais danoso aos riachos do que o rural, devido a diminuição da riqueza de espécies e as alterações nas variáveis ambientais. As principais mudanças ambientais encontradas em riachos urbanos foram a diminuição da cobertura do dossel pela vegetação ripária e do oxigênio dissolvido e o aumento da condutividade elétrica e do assoreamento do leito. Além disso, houve uma diminuição significativa da similaridade morfológica entre as espécies de peixes nos mesohábitats de riachos urbanos em comparação com os rurais. Portanto, podemos concluir que o ambiente urbano leva à perda de espécies de peixes morfologicamente similares nos mesohábitats, restando apenas algumas espécies funcionalmente distintas.

3.
Acta sci., Biol. sci ; 43: e53075, 2021. graf, ilus
Article in English | LILACS, VETINDEX | ID: biblio-1460987

ABSTRACT

Plant tissue culture has emerged as an important tool to produce bioactive compounds from various plant species, including the sustainable production of limonoids that are receiving considerable attention due to the benefits associated with human health such as anticancer activities. The purpose of the present study was to evaluate the capacity of limonoids aglycone production from callus culture from sweet orange cv. Pera (Citrus sinensis) seeds and identify the compounds produced in this cell line. Callus induction occurred in Murashige and Skoog medium supplemented with 2,4-dichlorophenoxyacetic (2,4-D), malt extract, agar and coconut water. For the analysis and identification of the limonoids, CG-MS-EI ion-positive mode and UPLC-QTOF-ESI were used operating in positive and negative mode. An intense peak corresponding to limonin appeared in the callus extracts at a retention time of 58.1 min. in CG-MS-EI and four major limonoids aglycone by positive ion mode UPLC-QTOF-ESI: limonin, nomilin, deacetylnomilin, and nomilinic acid. The culture medium was efficient at the bioproduction of limonoids aglycone in callus cultures of C. sinensis seeds. Therefore, data obtained from UPLC-QTOF-ESI proved its importance at identifying new compounds that benefit human health, and may assist future work in the identification of known or new limonoids in Citrus species and related genera.


Subject(s)
Biotechnology , Citrus sinensis/chemistry , Phytochemicals , Limonins/classification
4.
Acta sci., Biol. sci ; 42: e49835, fev. 2020. map, tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1460923

ABSTRACT

Morphological similarity, resource sharing, and differences in habitat use by species are factors that favor their coexistence. The objective of this study was to test possible differences in ecomorphology and diet composition of two Heptapterids (Imparfinis mirini and Cetopsorhamdia iherengi) to identify patterns related to resource use. Samplings were carried out in ten streams in Southern Brazil and 123 individuals were caught. A total of 21 ecomorphological indices were calculated for each individual and the volumetric and occurrence methods were used to quantify stomach contents. Both species presented significant differences in some ecomorphological traits, mainly related to foraging behavior. Even though both species were considered insectivorous, the consumed feeding resources differed between them. Cetopsorhamdia iheringi diet was dominated by Simuliidae and terrestrial Coleoptera larvae, while Imparfinis mirini, presented a diet dominated mainly by Trichoptera larvae, Ephemeroptera nymph, and Annelida. Although ecomorphological patterns cannot be used as an absolute factor to explain diet variations, they provide relevant information about how species share resources. These mechanisms allow us to obtain important subsidies for the conservation and management of freshwater ecosystems since they provide an effective understanding on the interactions that occur between the species.


Subject(s)
Animals , Trophic Levels , Catfishes/anatomy & histology , Catfishes/growth & development
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