Andrea Onofri

Influence of abiotic variables on culturable yeast diversity in two distinct Alpine glaciers

The influence of some abiotic variables (pH, dry weight, organic carbon, nitrogen and phosphorous) on culturable yeast diversity in two distinct, but adjacent Alpine glaciers (Glacier du Géant, France, and Miage Glacier, Italy) was investigated. In all, 682 yeast strains were isolated and identified by D1/D2 and ITS sequencing as belonging to species of the genera Aureobasidium, Candida, Bulleromyces, Cryptococcus, Cystofilobasidium, Dioszegia, Guehomyces, Holtermanniella, Leucosporidiella, Mrakia, Mrakiella, Rhodotorula, Sporidiobolus, Sporobolomyces and Udenyomyces. Overall, the most represented genera were Cryptococcus (55% of isolates), Rhodotorula (17%) and Mrakia (10%). About 10% of strains, presumably belonging to new species (yet to be described), were preliminarily identified at the genus level. Principal component analysis (PCA) revealed that organic carbon, nitrogen and phosphorous are apparently mostly related to culturable yeast abundance and diversity. In this context, the hypothesis that the frequency of isolation of certain species may be correlated with some organic nutrients (with special emphasis for phosphorous) is discussed.

Diagnostic Value of Conjunctival Swab Sampling Associated with Nested PCR for Different Categories of Dogs Naturally Exposed to Leishmania infantum Infection

ABSTRACT The objective of the present study was to evaluate the diagnostic performance of a noninvasive assay, conjunctival swab (CS) nested-PCR (n-PCR), for diagnosing canine leishmaniasis (CanL) in different stages of infection in comparison to the performance of the indirect immunofluorescence antibody test (IFAT), lymph node microscopy, and buffy coat n-PCR. To this end, we performed a cross-sectional survey among 253 nonselected dogs in areas of endemicity in central Italy. We also performed a longitudinal study of CS n-PCR among 20 sick dogs undergoing antileishmanial treatment. In the first study, among the 72 animals that were positive by at least one test (28.45%), CS n-PCR showed the best relative performance (76.38%), with a high concordance in comparison to standard IFAT serology (κ = 0.75). The highest positivity rates using CS n-PCR were found in asymptomatic infected dogs (84.2%) and sick dogs (77.8%); however, the sensitivity of the assay was not associated with the presence of clinical signs. In the follow-up study on treated sick dogs, CS n-PCR was the most sensitive assay, with promising prognostic value for relapses. The univariate analysis of risk factors for CanL based on CS n-PCR findings showed a significant correlation with age (P = 0.012), breed size (P = 0.026), habitat (P = 4.9 × 10−4), and previous therapy (P = 0.014). Overall, the results indicated that CS n-PCR was the most sensitive assay of the less invasive diagnostic methods and could represent a good option for the early and simple diagnosis of CanL infection in asymptomatic animals and for monitoring relapses in drug-treated dogs.

Differential susceptibility in a specialised aphidophagous ladybird, Platynaspis luteorubra (Coleoptera: Coccinellidae), facing intraguild predation by exotic and native generalist predators

Abstract The establishment of exotic generalist predators raises concern about possible domination of the invaded community and displacement of native species. In this respect, recent studies suggest that specialists are likely to be more at risk of niche displacement than generalists, thereby compromising biological control in agroecosystems. Under laboratory conditions, we examined the susceptibility of a specialised myrmecophilous ladybird, Platynaspis luteorubra Goeze, as intraguild (IG) prey of generalist native (Oenopia conglobata L. and Adalia bipunctata L.) and exotic (Harmonia axyridis Pallas) coccinellid species. We described parameters of predatory behaviour (for example, attack rate and effectiveness of antipredator defence) and their variation among predators. Furthermore, we estimated the effect of these parameters on the time to predation using a Cox proportional hazards model. We found that A. bipunctata was the most effective IG predator of P. luteorubra, with the highest rate of successful attacks; however, P. luteorubra was not very susceptibile to attack by O. conglobata or H. axyridis, and these species exhibited lower rates of successful attack and predation. Our results, together with field observations, suggest that IG predation is a factor that fosters niche specialization in P. luteorubra and decreases the realised niche of this species in central Italy. Furthermore the lower susceptibility of P. luteorubra to H. axyridis may be due to a lack of historical co-occurrence between preimmaginal stages, possibly arising from differental selection of oviposition sites.

Response surface methodology as optimization strategy for asymmetric bioreduction of (4S)-(+)-carvone by Cryptococcus gastricus

Response surface methodology was applied in optimizing the asymmetric bioreduction of (4S)-(+)-carvone to dihydrocarvone (with low incidence of unsought side reactions) by using whole-cells of Cryptococcus gastricus. A factorial design (2(5)) including five independent variables was performed: X(1)=incubation time; X(2)=pH; X(3)=amount of whole-cells; X(4)=concentration of (4S)-(+)-carvone; X(5)=concentration of cofactor-recycling system. The utilization of glucose and glycerol as cofactor-recycling systems was checked. On the basis of the results of factorial design, three independent variables (X(1), X(3) and X(4)) out of five were further selected for performing a central composite design (CCD). First and second order polynomial equations obtained by CCD were used to select the optimal values of independent variables in order to maximize the bioreduction yield of (4S)-(+)-carvone and, at the same time, to minimize the occurrence of side reactions (i.e. further reduction of dihydrocarvone to dihydrocarveol).

Biofortification (Se): Does it increase the content of phenolic compounds in virgin olive oil (VOO)?

Extra-Virgin Olive Oil (EVOO) is a fundamental component of the Mediterranean diet and it may contain several anti-oxidant substances, such as phenols. Previous research has shown that this food may be enriched in phenols by spraying a sodium-selenate solution (100 mg L-1 Se) onto the crop canopy before flowering. The aim of this research was to evaluate the effect of this Se-fertilization before flowering (cv. Leccino) on the phenolic profile of EVOOs, and test to what extent such effects depend on the weather pattern, as observed in two contrasting experimental seasons (2013 and 2014). Results showed that Se-fertilisation enriched EVOOs both in selenium (up to 120 μg kg-1) and in phenols (up to 401 mg kg-1). This latter enrichment was related to an increase in PAL (L-Phenylalanine Ammonia-Lyase) activities and it was largely independent on the climatic pattern. Considering the phenolic profile, oleacein, ligustroside, aglycone and oleocanthal were the most affected compounds and were increased by 57, 50 and 32%, respectively. All these compounds, especially oleacein, have been shown to exert a relevant anti-oxidant activity, contributing both to the shelf-life of EVOOs and to positive effects on human health. It is suggested that Se-fertilisation of olive trees before flowering may be an interesting practice, particularly with poor cultivars and cold and rainy weather patterns, which would normally lead to the production of EVOOs with unfavourable phenolic profile.

Histological and immunohistochemical studies of changes in myenteric plexuses and in interstitial cells of Cajal associated with equine colic.

In this study we investigated the histological changes of the myenteric plexuses and interstitial cells of Cajal (ICC) in gut samples from horses with colic to try to find results useful in the prognostic evaluation of enteric lesions. A morphologic and quantitative study of myenteric ganglia, ganglion cells and neuronal chromatolytic and necrotic changes of 24 horses with colic was performed. For ganglion cells, enteroglial cells and ICC immunolabeling was also performed to identify cell functional disorders. A significant increase of neuronal chromatolysis and necrosis occurred in horses suffering from colic throughout the gut. The neuron-specific enolase (NSE) and synaptophysin immunoreaction quantified with image analysis showed a significant loss of neuronal activity in all intestinal tracts of the animals under study associated with a significant loss of ICC immunoreactivity. The results supports immunohistochemical evaluation of ENS and ICC as a useful tool along with morphometric investigations in the evaluation of gut lesions produced during colic syndrome.

Changes in the Fusarium Head Blight Complex of Malting Barley in a Three-Year Field Experiment in Italy

In this study, conducted for three years on eleven malting barley varieties cultivated in central Italy, the incidence of different mycotoxigenic fungal genera, the identification of the Fusarium species associated with the Fusarium Head Blight (FHB) complex, and kernels contamination with deoxynivalenol (DON) and T-2 mycotoxins were determined. The influence of climatic conditions on Fusarium infections and FHB complex composition was also investigated. Fusarium species were always present in the three years and the high average and maximum temperatures during anthesis mainly favored their occurrence. The FHB complex was subject to changes during the three years and the main causal agents were F. poae, F. avenaceum, F. tricinctum and F. graminearum, which, even if constantly present, never represented the principal FHB agent. The relative incidence of Fusarium species changed because of climatic conditions occurring during the seasons. The FHB complex was composed of many different Fusarium species and some of them were associated with a specific variety and/or with specific weather parameters, indicating that the interaction between a certain plant genotype and climatic conditions may influence the presence of Fusarium spp. causing infections. With regard to mycotoxin contamination, T-2 toxin, in some cases, was found in kernels at levels that exceeded EU recommended values.

Improved multivariate analyses to discriminate the behaviour of faba bean varieties

Agricultural systems of Southern European regions are often based on short rotations of winter cereals and are thus subject to agro-ecological problems such as decreasing biodiversity, loss of soil fertility and increasing reliance on mineral fertilisers. Introducing new crops such as new varieties of faba bean, and new production methods, e.g. different planting times, may increase the sustainability of farming systems. To advance the use of these methods, both multi-environment field experiments and improved statistical methods to summarise and interpret results are needed. This report summarizes experiments conducted over three years and two locations where we compared phenology, morphology and yield of six faba bean, Vicia faba L., genotypes, sown in November and February. We have analyzed the data using canonical variate and additive main effect multiplicative interaction (AMMI). We demonstrate how such methods may be useful to obtain relevant information about a more successful introduction of faba bean in southern Europe. Our results show that sowing in November is much more suitable to Southern European regions than a February planting. Indeed, for the November planting, beans flower earlier and pods fill before the drought period. Concerning morphology, November sown plants were taller of 0.93 m versus 0.79 m on average; gave a lower insertion of first fertile branch of 0.44 m versus 0.51 m; gave a higher number of lateral branching per plant, of 1.5 versus 0.8; and gave a higher number of pods per plant of 10.2 versus 7.6. On the average yield levels were the highest for November sown varieties, of 3.55 versus 2.66 t ha−1. These findings indicate autumn sown faba bean could be introduced in Southern European regions. Using adequate varietal selection, this crop may improve the agro-environmental sustainability of farming systems. These results also highlight the usefulness of canonical variate and AMMI analysis, as 576 morphological data, e.g. 6 varieties, 2 sowing times, 6 environments and 8 variables, and 72 yield data, e.g. 6 varieties, 2 sowing times and 6 environments, can be summarised in two bi-plots, clearly depicting the effect of sowing dates on crop morphology and yield, across locations and years. Such methods deserve a more widespread use when it is necessary to interpret crop response to environmental and agronomic factors.

Factors Involved in Uptake of Lead by Some Edible Crops Grown in Agricultural Soils of Central Italy

This study was organized to investigate the bioavailability of Pb in soil, as affected by soil type and crop species. The four most representative forms of Pb in soil (exchangeable, bound to carbonates, bound to the Fe-Mn oxides, and bound to organic matter) were considered, and their respective contribution to the uptake of this metal was determined. Four edible crops (lettuce, radish, tomato, and Italian ryegrass) were grown in four soil types, both nonspiked and spiked with 200 mg Pb kg−1. Chemical analyses were carried out to determine the amount of Pb sorbed from the soil and stored in the different plant organs. The bioaccumulation factor (BAF) and the translocation factor were derived and used to compare plant species. Results showed that all the test plants sorbed 10 to 30 times more Pb from spiked soils, as compared with nonspiked soils. The BAF and translocation factor showed that, excluding Italian ryegrass, all the crops sorbed less Pb from the soils containing Ca carbonate. On the basis of BAF, lettuce, tomato, and Italian ryegrass could be classified as crops with high Pb uptake ability in all soils. Concerning the distribution of Pb within the plant, all species showed the tendency to store this metal mainly in roots. The translocation to above-ground organs was the highest with lettuce, tomato (with reference to non edible above-ground organs) and Italian ryegrass, whereas radish showed the lowest translocation ability, together with the lowest uptake ability.

Germination response of four pasture species to temperature, light, and post-harvest period

Abstract The purpose of this research was to explore the effect of temperature, light, and post-harvest period, and their interactions, on seed germination ecology of four common pasture species in the Mediterranean environment. Mature seeds of Diplotaxis erucoides, Hirschfeldia incana, Hyoseris scabra (Mediterranean distribution) and Sonchus oleraceus (cosmopolitan distribution) were subjected to seven constant temperatures (10–40°C, at intervals of 5°C) under continuous darkness, or a 12 h/12 h light/dark photoperiod at 30, 150 and 270 days after harvest (DAH). Cumulative germination and germination speed were determined. In all the tested species, except S. oleraceus, light significantly enhanced germination. S. oleraceus seeds maintained germination values over 90%, in a wide range of temperatures (10–35°C), in the dark as well as in light. Seeds of H. incana germinated well soon after seed dispersal. In D. erucoides and H. scabra, germination increased with storage period, while in S. oleraceus there was no effect of seed age. In all the species, moreover, no germination was recorded at 40°C. Temperature, light, and post- harvest requirement may be regarded as an adaptation strategy to ensure optimal conditions for seedling development and survival in Mediterranean species, while the species with a cosmopolitan distribution germinates under almost all tested conditions.