RESUMO
Chlorpyrifos (CPF) has been used worldwide, but its possible negative effects on macrophytes have been scarcely studied. The main goal of the present work was to assess the potential phytotoxic effects of CPF on different stages (seed and seedling) of the wetland macrophyte Bidens laevis. During the germination of seeds, stimulation of radicle growth at low concentrations of CPF (10 µg/L) and inhibition of its elongation at 80 µg/L CPF were observed. In seedlings, concentrations ≤ 160 µg/L CPF did not exhibit adverse effects on growth after 7 days of exposure, despite the decrease of photosynthetic pigments and carotenoids observed at 40 µg/L CPF compared to the control. Environmentally relevant concentrations of CPF altered neither oxidative stress biomarkers nor pigment contents in seedlings exposed for 48 h, suggesting CPF would be non-toxic to B. laevis in natural scenarios.
Assuntos
Bidens , Clorpirifos , Poluentes Químicos da Água , Áreas Alagadas , Clorpirifos/toxicidade , Poluentes Químicos da Água/toxicidade , Bidens/efeitos dos fármacos , Inseticidas/toxicidade , Germinação/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimentoRESUMO
Pesticide contamination and its adverse effects on native freshwater species continue to be a worldwide major concern, mainly in developing countries. Passive biomonitoring of pesticide pollution in shallow lakes may be achieved by the simultaneous use of fish and wetland plants. Thus, the present study aimed to evaluate the occurrence of current-use pesticides in the surface water of a shallow lake of the Austral Pampas region (Buenos Aires Province, Argentina) surrounded by intensive agricultural activities and its relationship with a battery of biomarkers, including oxidative stress and genotoxicity, in two native species, the fish Oligosarcus jenynsii and the macrophyte Bidens laevis. A total of 26 pesticide residues were analyzed, and the main ones detected were glyphosate and its metabolite aminomethylphosphonic acid (AMPA), chlorpyrifos, and imidacloprid. In O. jenynsii, hydrogen peroxide (H2O2) content in the liver increased with chlorpyrifos occurrence, while malondialdehyde (MDA) levels in the brain and liver increased with the presence of both chlorpyrifos and glyphosate. In B. laevis, H2O2 and MDA levels in leaves and roots increased with AMPA occurrence. Also, leaf H2O2 contents and root MDA levels increased with chlorpyrifos concentration. In contrast, catalase and peroxidase activities in roots decreased with AMPA and chlorpyrifos occurrence. In both species, mainly H2O2 and MDA levels demonstrated their sensitivity to be used as biomarkers in the biomonitoring of current-use pesticide pollution in shallow lakes. Their use may provide information to plan strategies for environmental conservation by government institutions or decision-makers, and to assess the biota health status.
Assuntos
Clorpirifos , Praguicidas , Poluentes Químicos da Água , Animais , Praguicidas/análise , Lagos , Clorpirifos/toxicidade , Monitoramento Biológico , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/análise , Argentina , Peróxido de Hidrogênio , Monitoramento Ambiental , Glifosato , Estresse Oxidativo , Peixes/metabolismo , Biomarcadores/metabolismo , Poluentes Químicos da Água/análiseRESUMO
In recent years, natural alternatives have been sought for the control of beekeeping pathologies; in the case of American Foulbrood (AFB) disease, the use of synthetic antibiotics was prohibited due to honey contamination and the generation of resistant bacteria. The significant increase in population growth worldwide has led to great concern about the production of large amounts of waste, including those from agribusiness. Among the most important beverages consumed is coffee, generating thousands of tons of waste called spent coffee grounds (SCG). The SCG is a source of many bioactive compounds with known antimicrobial activity. The aims of the present work were: (1) to obtain and chemically analyse by HPLC of SCG extracts (SCGE), (2) to analyse the antimicrobial activity of SCGE against vegetative form of Paenibacillus larvae (the causal agent of AFB), (3) to evaluate the toxicity in bees of SCGE and (4) to analyse the effect of the extracts on the expression of various genes of the immune system of bees. SCGs have a high content of phenolic compounds, and the caffeine concentration was of 0.3%. The MIC value obtained was 166.667 µg/mL; the extract was not toxic to bees, and interestingly, overexpression of abaecin and hymenoptaecin peptides was observed. Thus, SCGE represents a promising alternative for application in the control of American Foulbrood and as a possible dietary supplement to strengthen the immune system of honeybees. Therefore, the concept of circular bio-economy could be applied from the coffee industry to the beekeeping industry.
Assuntos
Paenibacillus larvae , Abelhas , Animais , Café , Peptídeos Antimicrobianos , Antibacterianos/farmacologia , LarvaRESUMO
Dicamba (DIC) is one of the most applied auxin herbicides worldwide. Sublethal effects in the South American native fish Jenynsia lineata exposed to DIC concentrations close to environmental concentrations (0.03-30 µg/L) during 48 h were analysed thorough the evaluation of catalase (CAT), glutathione S-transferase (GST), superoxide dismutase (SOD) activities and malondialdehyde (MDA) and H2O2 levels for detecting potential oxidative stress. In gills MDA increased showing oxidative damage probably because of an inefficient antioxidant defense. This response evidenced the important role of gills as an organ of direct contact with waterborne contaminants. In addition, other changes in the biomarkers of oxidative stress were observed such as the inhibition of SOD activities in brain and the inhibition of GST in liver. These results show that short- term exposures to environmentally relevant concentrations of DIC could induce sublethal effects in native fish.
Assuntos
Dicamba , Peixes , Herbicidas , Estresse Oxidativo , Animais , Dicamba/toxicidade , Glutationa Transferase , Herbicidas/toxicidade , Peróxido de Hidrogênio , América do Sul , Superóxido DismutaseRESUMO
Wild pollinators are declining and the number of managed honey bee colonies is growing slower than agricultural demands for pollination. Because of these contrasting trends in pollinator demand and availability, breeding programs for many pollinator-dependent crops have focused on reducing the need for pollinators. Although numerous crop varieties are now available in the market with the label of pollinator-independent, the real dependence of these varieties on pollinators is mostly unknown. We evaluated the hypothesis of pollinator independence in the Independence almond variety, the fastest growing variety in California that is the main almond production region in the world. In this presumed pollinator-independent variety, we measured the effect of honey bees on fruit set, yield, and kernel nutritional quality at tree level. Fruit set was 60% higher in bee-pollinated than bee-isolated trees, which translated into a 20% increase in kernel yield. Despite its effect on almond production, there was no evidence that bee visitation affected almond nutritional quality. Based on these results, we recommend the use of bees, whether they are wild or managed, to maximize yield even in self-fertile almond varieties.
Assuntos
Abelhas/fisiologia , Produtos Agrícolas/crescimento & desenvolvimento , Polinização/fisiologia , Prunus dulcis/fisiologia , Animais , Flores/fisiologia , Frutas/fisiologiaRESUMO
The fungicide tebuconazole (TBZ) has been used to prevent terrestrial fungi in agroecosystems, but it can also induce negative effects to non-targeted aquatic organisms, such as plants. The aim of the present work was to evaluate the potential cyto- and genotoxicity of TBZ in the aquatic macrophyte Bidens laevis, exposed to a range of concentrations of 0.1-100 µg/L. Mitosis in root tips were analyzed showing decreased mitotic index and an increase of chromosomal aberrations at 10 and 100 µg/L. The regression of TBZ concentration vs. aneugenic aberrations was significant, indicating the mechanism of genotoxicity. The specific growth rate (Gr) for total length decreased in plants exposed to 0.1, 10 and 100 µg/L. Gr for root decreased in plants exposed at 0.1 and 10 µg/L, reaching a maximum percent inhibition root growth rate (Ir) of 68.8%. These results show that TBZ resulted cyto- and genotoxic to B. laevis at environmentally relevant levels.
Assuntos
Bidens/efeitos dos fármacos , Fungicidas Industriais/toxicidade , Triazóis/toxicidade , Bidens/genética , Bidens/crescimento & desenvolvimento , Aberrações Cromossômicas/induzido quimicamente , Dano ao DNA , Meristema , Fotossíntese/efeitos dos fármacos , Análise de Regressão , Áreas AlagadasRESUMO
Neonicotinoids are one of the most widely used insecticides in the world. DNA damage is considered an early biological effect which could lead to reproductive and carcinogenic effects. The present study aimed to evaluate DNA damage and bases oxidation as a mechanism of genotoxicity, on the freshwater fish Australoheros facetus acutely exposed to imidacloprid (IMI). The Comet assay with the nuclease ENDO III enzyme was performed for detecting pyrimidine bases oxidation using blood samples. Micronucleus and other nuclear abnormalities frequencies were also quantified. A significant increase of damage index at 100 and 1000 µg/L IMI was detected; while ENDO III score increased from 1 to 1000 µg/L IMI; varying both in a linear concentration-response manner. MN frequency increased in fish exposed to 1000 µg/L IMI. These results show that short-term exposures to environmentally relevant concentrations of IMI could affect the genetic integrity of fishes through oxidative damage.
Assuntos
Dano ao DNA/efeitos dos fármacos , Inseticidas/toxicidade , Neonicotinoides/toxicidade , Nitrocompostos/toxicidade , Animais , Ciclídeos/genética , Ciclídeos/metabolismo , Ensaio Cometa , Água Doce , Testes para MicronúcleosRESUMO
Using molecular techniques, we documented the presence of Nosema ceranae in honeybees (Apis mellífera) from Argentina. Samples were collected from A. mellifera colonies in 38 districts of Buenos Aires province, Argentina. Molecular characterization was achieved with a multiplex PCR-based method, which allows parallel diagnosis of N. ceranae and N. osema apis. N. ceranae was identified in all the samples analyzed. Moreover, coinfections with N. apis were detected in Balcarce and Maipú districts. We identified three rRNA sequence variants of N. ceranae, which may represent diverse sources of bee importation. The results suggest that N. ceranae is widely distributed in Argentina and that the genetic variation observed between the different isolates could be related with the difference in the symptomatology found previously by our work group. Our results highlight the need to re-assess the health protocols currently in force so that they recognize N. ceranae as the main causal agent of Nosemosis in this country.
Assuntos
Abelhas/microbiologia , Variação Genética , Nosema/classificação , Nosema/isolamento & purificação , Animais , Argentina , Análise por Conglomerados , Coinfecção , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Genes de RNAr , Dados de Sequência Molecular , Reação em Cadeia da Polimerase Multiplex , Nosema/genética , Filogenia , RNA Fúngico/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Nosemosis, a disease caused by a microsporidian infection, is one of the most frequently observed parasitic pathologies affecting adult honeybees. Presently, Nosema ceranae seems to be the main microsporidian infection in Apis mellifera. The antibiotic fumagillin is the only compound available to treat Nosema diseases; however, it is no longer licensed in most EU member states; therefore, the need to identify new molecules/substances prevails. The intent of this paper is to test bacterial metabolites by Bacillus and Enterococcus strains, isolated from bee midgut and honey. The toxicity on bees and the antiparasitic activity on N. ceranae were assessed under laboratory conditions. Results did not yield toxicity for the administered surfactin or bacteriocin concentrations. Spores exposed to direct contact with a particular surfactin revealed a significant infectivity reduction when inoculated on bees. This surfactin, administered ad libitum from the individuals' emergence, led to a significant reduction in parasitosis development when bees were infected with untreated spores 7 days postemergence. Based on the results obtained, one of the surfactins is herein postulated as a molecule capable of reducing N. ceranae development, acting either by direct exposure to purified spores or incorporated into the digestive tract of the bee.