1,721,075 research outputs found
Heavy metal bioaccumulation in Mytilus galloprovincialis: A transplantation experiment in Venice Lagoon
No full textMussels were transplanted from a marine reference site to a polluted area of the Venice Lagoon to study heavy metal bioaccumulation responses in soft tissues and shells. Soft tissue levels of Mn, Cu, Fe and Cr were initially lower in reference than in lagoon resident mussels, while no differences were observed for Pb and Zn. After one month, the Mn, Cu, Fe and Cr levels in the transplanted mussels increased and overtook both values recorded in resident and marine organisms. Two months after transplantation, metal levels dropped off. At the time of the last sampling, the metal levels seemed to stabilize at lagoon values, except for Cu. Shell levels of Cu, Zn and Pb were lower in mussels from the reference site than in those resident in the lagoon. After three month from transplantation, the bioaccumulation shell data indicated a sharp increase in Mn, Fe and Zn overtaking the levels of lagoon resident bivalves. The results show the usefulness of field transplantation experiments in studying bioaccumulation responses in polluted coastal environments
Effects of zinc on the polychaete Dinophilus gyrociliatus: a life table response experiment
No full textA life-table response experiment (LTRE) was performed in order to study the effects of enhanced zinc on the survival, fecundity and demographic indices of Dinophilus gyrociliatus (Polychaeta). A control group and three treated cohorts kept in artificial seawater enriched with nominal concentrations of zinc at 0.25, 0.50 and 1.00 g Zn/ml, respectively, were considered. Zinc marginally affected survival but had a strong impact on the reproduction of D. gyrociliatus. Zinc enrichment had no effect on age at maturity, whereas it induced a slight increase in fecundity during the early reproductive phases at 0.50 and 1.00 g Zn/ml, and a sharp decrease in fecundity from the twentieth day of life at all levels of metal enrichment tested. Treated groups were characterized by a marked reduction of the net growth rate (R0) and a decrease in generation time (T) with respect to the control groups, but no effect on life expectancy (e0) or on population growth rates () was observed. R0 and , which are the most commonly used indices of fitness, were not equally susceptible to zinc. appears less sensitive to stress induced by metal enrichment with respect to R0 and other life history traits like age-specific fecundity. D. gyrociliatus appears to be an appropriate bioindicator species in LTRE to assess the consequences of environmental heavy metals on individual life-history and population dynamics
Effetti di zinco su più generazioni di Dinophilus gyrociliatus: un approccio demografico.
No full textThe effects of zinc on life history and populations of Dinophilus gyrociliatus (Polychaeta) were studied. The life tables of three successive generations (P, F1, F2) were derived from a control cohort and a threated cohort kept in artificial seawater enriched with 1.0 ppm zinc. Zinc affected survival and fecundity of the three successive generations with different modality and intensity, determining a geralized reduction of all demographic indices and different demographic responses among generations
Arricchimento ambientale di metalli ed effetti sulla demografia del polichete Dinophilus gyrociliatus
No full text[online] URL:http://www.xiiicongresso.societaitalianaecologia.org/articles/Mauri-86.pd
Transient transformation meets gene function discovery: the strawberry fruit case
Full text linkBeside the well known nutritional and health benefits, strawberry (Fragaria X ananassa) crop draws increasing attention as plant model system for the Rosaceae family, due to the short generation time, the rapid in vitro regeneration, and to the availability of the genome sequence of F. X ananassa and of the closely related F. vesca species. In the last years, the use of high-throughput sequence technologies provided large amounts of molecular information on the genes possibly related to several biological processes of this crop. Nevertheless, the function of most genes or gene products is still poorly understood and needs investigation. Transient transformation technology provides a powerful tool to study gene function in vivo, avoiding difficult drawbacks that typically affect the stable transformation protocols, such as transformation efficiency, transformants selection and regeneration. In this review we provide an overview of the use of transient expression in the investigation of the function of genes important for strawberry fruit development, defence and nutritional properties. The technical aspects related to an efficient use of this technique are described, and the possible impact and application in strawberry crop improvement are discussed
Heat treatments effect on Cadophora luteo-olivacea of kiwifruit
Full text linkAbstract
Heat treatments represent alternative methods to fungicides to control latent fruit pathogens, such as Cadophora luteo-olivacea of kiwifruit. The study reports the efficacy of different hot water and hot air treatments (45 °, 50 °, 55 °, 65 °, and 70 °C with the duration respectively of 10, 15 and 20, 10, 65, 3 min) on the conidial and mycelial fungal isolates growth by in vitro assays. Both treatments at 70 °C were the most effective on the conidial and mycelial growth of C. luteo-olivacea isolates. On the mycelial growth, treatment efficacy was on average 88% and 71%, respectively, and on conidial growth by 100% and 91.3%. A significant reduction of xylanase and pectinase enzyme activities of the isolates was detected after hot water and air treatment (70 °C × 3 min). Both treatments showed, in most cases, the total reduction, sometimes variable with the target isolate. Hot air treatment was the most efficient treatment by reducing the skin pitting incidence in in vivo experiments, showing an efficacy of 46.6%, on average. Results show that heat treatments are effective against C. luteo-olivacea, but ‘time × temperature’ combinations remain the main challenge to develop
Aureobasidium pullulans volatile organic compounds as alternative postharvest method to control brown rot of stone fruits
Full text linkVolatile compounds produced by L1 and L8 strains were assayed against mycelia and conidia growth of Monilinia laxa, M. fructicola, M. polystroma, and M. fructigena of stone fruits. Results showed that volatile metabolites inhibited significantly pathogens growth, in particular M. fructigena mycelium growth (70% by L1 and 50% by L8) and M. fructicola conidia germination (85% by L1 and 70% by L8) compared to the control. Moreover, the antagonistic activity was enhanced by the addition of asparagine (120 mg L-1) in the culture media composition. Synthetic pure compounds were tested in vitro on pathogens mycelial and conidia growth and their EC50 values were estimated, confirming 2-phenethyl as the most active compound. For this reason 2-phenethyl and VOCs of both yeast strains were assayed in vivo on cherry, peach, and apricot fruits. Regarding peach fruit, both treatments, yeasts and pure compounds, displayed the best inhibiting action against all the pathogens especially against M. laxa (100% by L1, 84% by L8 and 2-phenethyl). ATR/IR spectroscopy analysis showed how VOCs produced by both strains increase the fruit waxes complexity reducing the pathogens attack so playing an essential role in the antagonistic activity of both yeast strains and on fruit structural composition
Prevenzione del riscaldo della pera Abate Fétel con stress da basso O2
No full textLa prevenzione del Riscaldo superficiale delle pere Abate Fétel, dopo l’abolizione dei trattamenti con etossichina, si è basata esclusivamente sull’impiego dell’1-MCP. In altre cultivar la conservazione con basso O2 (<0.8%) ha consentito di prevenire efficacemente il riscaldo superficiale, mentre nella Abate Fétel, la prolungata esposizione a basso O2 determina la comparsa del riscaldo molle. Nel corso di tre anni di ricerche è stata valutato, su frutti di due raccolte successive, l’effetto dello stress da basso O2, indotto da una concentrazione inferiore alla soglia di estinzione della respirazione aerobica (0,3-0,5% O2), per 21 e 35 giorni. Lo stress per 21 giorni ha prevenuto il RS solo per 4 mesi, mentre quando è stato prolungato fino a 35 giorni è risultato efficace, anche dopo 6 mesi di conservazione in refrigerazione normale a -1°C. Il basso O2 ha rallentato il processo di maturazione come evidenziato dalla durezza, dal colore e dalla produzione di etilene al termine della conservazione. Il cospicuo aumento del contenuto di etanolo, rilevato dopo il periodo di stress da basso O2, è risultato fortemente ridotto dopo shelf-life. Il periodo di stress non ha indotto anomalie nelle caratteristiche organolettiche
Demographic responses of the polychaete Dinophilus gyrociliatus to chromium exposure
No full textThe effects of chromium on the life history and demography of Dinophilus gyrociliatus (Polychaeta) were studied on a control and three treated cohorts kept in artificial seawater enriched with nominal concentrations of chromium at 1.0, 1.4, and 1.6 mug/ml. Survival and fecundity were significantly reduced by chromium. Fecundity was higher in the chromium treatments than in the control group at the beginning of the reproductive period; however, overall, the highest fecundity was observed in the control. Life expectancy, net growth rate, and generation time were also significantly reduced by chromium. The population growth rate (lambda) was higher in the treated animals than in the controls. The differences in lambda between the treated animals and the controls (Deltalambda) were almost completely due to the differences in the life tables observed during the first three weeks of life. The differences in survival between the treated and control animals did not contribute to Deltalambda. The contribution to Deltalambda of the slight increase in age-specific fecundity in the early reproductive events compensated for the marked decrease in overall fecundity in the treated animals. The complex effects of chromium enrichment on D. gyrociliatus underline the importance of analyzing both individual and population responses when assessing the effects of pollutants on organisms. Our results confirm that D. gyrociliatus might serve as an indicator species in confined areas of polluted seawater such as lagoons and harbors
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