Impact of soil management on the functional activity of microbial communities associated to cork oak rhizosphere

The microbial ecology of cork oak rhizosphere was investigated using the Biolog community level physiological profile (CLPP) that provides a unique metabolic fingerprint helpful for the characterization of complex microbial communities. Microbial populations from the rhizosphere of cork oak plants growing at three different sites within the same area were characterized using CLPP and compared. The sites were distinguished by a different soil management under the tree cover and, in general terms, by a different anthropogenic impact. The comparison of metabolic fingerprints of the different microbial populations showed the existence of a relationship between general microbial activity and functional biodiversity in the rhizosphere and the level of anthropogenic impact. Particularly the presence of grazing animals, soil tillage and fire could be identified as the main factors affecting both the general microbial activity and the structure of microbial populations from cork oak rhizospheres

Recovery and sanitary selection of local vines of the Sardinia

A study was made on the recovery genotypes local grapevine with the aim to conserve them and to evaluate their health status and thus to improve the quality of the propagation material. Clone accessions of 61 vines were grafted and placed in a germoplasma field. The varieties that were considered enologically valuable were subjected to sanitary selection. Some vines showed indubitable healthy qualities, and should be immediately evaluated from an economical point view and then certificated. Possible sanitation treatments were also evaluated, with the aim of extending the number clone accessions to be included in experimental trials to access their yield

Season and altitude effects on milk fatty acid profile in Sarda dairy sheep flocks

Diet plays a major role in modulating the fatty acid composition of ruminant milk. It is also well known that the intake of fresh forages has a positive influence on polyunsaturated fatty acid (PUFA), particularly CLA and omega- 3, compared with diets based on dry forage and concentrates. Altitude influences, directly, grass availability and botanical composition of the pasture, and, indirectly, the amount of concentrate supplemented to the diet. Therefore, the altitude where farms are located at may give indirect information about the type of feeding system trough analysis of milk fat. The objective of this survey was to investigate variations in the milk fatty acid profile, focusing on the content of vaccenic acid (VA), conjugated linoleic acid (CLA) and n-3 fatty acid (FA), of Sarda dairy ewes flocks located at different altitudes throughout Sardinia. Bulk milk samples were collected in spring (April) and in summer (July) from 36 flocks located at different altitudes: 3 flocks in the lowlands (Low), 3 flocks in the hills (Hill) and 3 in the highlands (High) in 4 provinces (Sassari, Nuoro, Oristano and Cagliari) of Sardinia (Italy). Milk fatty acid profile was analyzed by gas-chromatography. Data were analyzed with a linear model with altitude (A), season (S), province (P) and altitude x season as fixed factors. The interaction was never significant. The season influenced significantly almost all fatty acids analyzed. The proportion of short chain FA (C4-C10) decrease (10.0 vs 7.0 mg/100 mg FA; P<0.01) and that of medium chain FA increase (43.2 vs 45.5 mg/100 mg FA; P<0.10) from spring to summer. The long chain FA did not vary between spring and summer but the concentration of oleic acid (C18:1 cis9) increased significantly from spring to summer (22.3 vs 25.1 mg/100 mg FA; P<0.01). The proportion of n-3 FA was higher in spring than summer (1.2 vs 0.7 for n- 3 FA; P<0.01). The variation in n-3 FA in milk fat was mainly due to the variation in a-linolenic acid (ALA; 18:3n- 3) which decrease from 1.0 to 0.5 mg/100 mg FA from spring to summer. The same pattern was showed by vaccenic acid (VA; trans-11 18:1) that decrease from 1.6 vs 0.8 mg/100 mg FA. No variation in cis9, trans11 CLA has been observed between spring and summer (1.0 vs 0.8 mg/100 mg FA). A reduction of PUFA (5.64 vs 5.10; P<0.10), n3/n6 ratio (0.38 vs 0.21) and content of C20:5 n-3 (0.13 vs 0.07 mg/100 mg FA) from spring to summer has been observed. Unexpectedly, the milk FA profile was not affected by altitude, except for C18:1 c9, probably because of the low number of samples analyzed

A Contribution to the study of the distribution of <i>Medicago-Sinorhizobium</i> symbiosis in Sardinia (Italy)

The paper summarizes the results of a Medicago-Sinorhizobium germplasm survey and collection carried out in the island of Sardinia (Italy) in 1998/99 and subsequent laboratory isolation of microbial strains, soil sample analyses and determination of Medicago species. According to a stratified sampling methodology, the major ecological characteristics of island's habitats were taken into account, collecting and surveying mostly in natural or semi-natural habitats (no roadside sites nor cultivated fields were sampled). Forty-six sites, widely distributed in semi-natural representative areas of Sardinia, ranging from sea level to above 1000 m asl, were sampled and 24 were surveyed to gather additional data on species distribution. Root nodules were collected from 15 species (13 annuals) out of the total 21 Medicago species recorded in Sardinia. Isolation of root nodule bacteria accessions and identification of 29 strains were achieved. A total number of 17 species were surveyed and mapped. The present study gives a first contribution to the knowledge of the present distribution of the species of the genus Medicago in Sardinia with special concern to the species recorded or sampled during the survey and highlights the presence of Medicago biodiversity hot spots

Middle Holocene Landscape evolution and settlements in the north-western coast of Sardinia: preliminary study of the Sant’Imbenia site

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PCR-based methods to discriminate Bacillus thuringiensis strains

Bacillus thuringiensis is a Gram positive bacterium that is used for the production of biopesticides. The toxic action of different strains and serovars ofB. thuringiensis can be extremely selective towards specific pests, or, in contrast, it can affect a wide variety of non-target organisms such as insects, vertebrates or humans. A reliable characterization of the cultivated strains is of primary importance for the biopesticide industry, in order to assess the contamination of the final product with strains with different pesticide actions or that might be dangerous for human health. The aim of this study was to develop useful methods for the typing of differentB. thuringiensis strains using two PCR-based methods, RAPD and Rep-PCR with BOXA1R and ERIC2 primers. The molecular fingerprints obtained using ERIC2-PCR showed a reliable ability to discriminateBacillus thuringiensis strains

The Effect of Inoculation on Growth, Nodulation and Nitrogen in Annual Clover Cultivars Grown at Two Mediterranean Locations of Sardinia, Italy

The legume's benefits are well-known and exploited in animal production systems, and the commercial availability of novel clover cultivars is an important opportunity for Mediterranean climatic areas. However, the successful performance of a legume species is strongly affected by the presence of specific rhizobia in the soil. The performances of 10 annual clover cultivars belonging to nine species, both uninoculated and inoculated, were compared at two locations in Sardinia (Italy). The rows (2 m length each) were established in autumn and seed inoculation with a selected commercial rhizobial strain was performed at sowing. In the following spring, shoot length, the number of root nodules, shoot dry matter yield and nitrogen concentration were determined on complete recovered plants. Inoculation affected shoot length, with significant differences at each site. It ranged from 7.9 to 39.7 cm. The average shoot DM production in the two locations ranged from 0.21 to 1.92 g per plant and there was a significant interaction of the location x cultivar. Inoculation significantly increased the growth of four cultivars. However, a cultivar selected in Sardinia, Trifolium brachycalycinum 'Antas', was irrespective of both location and inoculation, producing more shoot DM per plant than did the other clovers (about 1.80 g per plant). The results demonstrated that the clover agronomic performances differed among cultivars and locations. In addition, they highlighted that inoculation with a selected rhizobial strain is very useful for some clovers, suggesting that is preferable to ascertain at each site the need for clover inoculation

The Impact of Beehive Proximity, Human Activity and Agricultural Intensity on Diptera Diversity in a Mediterranean Mosaic of Agroecosystems, with a Focus on Pest Species

Diptera with their participation in pollination, significantly contribute to the maintenance of plant diversity, and they also have great potential for assessing habitat health and preserving it. A decline in their abundance and diversity has been recorded worldwide as a consequence of biotic, abiotic and anthropic alterations. Besides pollinators, these orders also include agricultural and forestry pests, which are a threat to cultivated and wild plants having great economic importance. Many pests have escaped from their native area, and it is important to monitor their spread to implement sustainable means of control. Our study provides baseline information on Diptera and Vespidae diversity in the Mediterranean mosaic of agroecosystems, giving information on the importance of human influence on insect diversity. We carried out an insect inventory in Istria, Croatia, using a set of traps placed in the proximity of beehives. This study was also important in determining the presence of pests and newly introduced species. A total of 94 species belonging to 24 families were recorded—7 important agricultural pests of Diptera and 17 new records for Croatia. The correlation between species diversity and environmental and anthropogenic factors leads to the conclusion that total insect species richness, pest richness, and first findings depend on human activities. The number of honeybee colonies negatively correlated with species richness, while anthropic influence positively affected total and pest species richness

Microbiologia e valutazione igienico-sanitaria della salsiccia sarda

In this study we evaluated the microbiological status of the Salsiccia sarda with special emphasis on the microbial indicators of the hygienic and sanitary conditions. Moreover, the evolution of the autochthonous microflora has been monitored during the entire production process. For these aims, microbiological analyses were carried out on different samples of minced meat and sausages at different ripening times. Despite the results showed some critical points in the hygienic and sanitary conditions, substantiated by a significant presence of Escherichia coli, Salmonella and Listeria spp. were not found in any sample. The dominant microflora of Salsiccia sarda was composed by Lactobacillus curvatus, L. plantarum, Staphylococcus xylosus and Debaryomyces hansenii. The knowledge of the microbial ecology of this typical sardinian food-stuff is a significant baseline for the development of autochthonous starter cultures to be employed in the production process. The use of such cultures may allow a better management of the process and guarantee suitable qualitative traits of this traditional ripened sausage. Nel presente lavoro sono stati valutati i microrganismi di interesse igienico-sanitario e l'evoluzione della microflora della Salsiccia sarda. Prelievi e analisi microbiologiche sono stati effettuati sulla carne macinata e sulla salsiccia a tempi diversi di maturazione. I risultati hanno mostrato che, nonostante le criticità inerenti le condizioni igienico-sanitarie rilevate in alcune fasi tecnologiche e confermate dalla presenza di Escherichia coli, non sono stati ritrovati batteri ascrivibili ai generi Salmonella e Listeria. Le specie microbiche risultate predominanti sono state Lactobacillus curvatus, L. plantarum, Staphylococcus xylosus e Debaryomyces hansenii. La conoscenza dell'ecologia microbica di questo prodotto tipico costituisce un punto di partenza per la messa a punto di colture starter autoctone da impiegare nei processi di trasformazione. L'utilizzo di tali colture consentirebbe una migliore gestione del processo garantendo adeguati standard qualitativi ad un prodotto tradizionale come la Salsiccia sarda

Using biochar for environmental recovery and boosting the yield of valuable non-food crops: the case of hemp in a soil contaminated by potentially toxic elements (PTEs)

Hemp (Cannabis sativa L.) is known to tolerate high concentrations of soil contaminants which however can limit its biomass yield. On the other hand, organic-based amendments such as biochar can immobilize soil contaminants and assist hemp growth in soils contaminated by potentially toxic elements (PTEs), allowing for environmental recovery and income generation, e.g. due to green energy production from plant biomass. The aim of this study was therefore to evaluate the suitability of a softwood-derived biochar to enhance hemp growth and promote the assisted phytoremediation of a PTE-contaminated soil (i.e., Sb 2175 mg kg-1; Zn 3149 mg kg-1; Pb 403 mg kg-1; and Cd 12 mg kg-1). Adding 3% (w/w) biochar to soil favoured the reduction of soluble and exchangeable PTEs, decreased soil dehydrogenase activity (by ~2.08-fold), and increased alkaline phosphomonoesterase and urease activities, basal respiration and soil microbial carbon (by ~1.18-, 1.22-, 1.22-, and 1.66-fold, respectively). Biochar increased the abundance of selected soil culturable microorganisms, while amplicon sequencing analysis showed a positive biochar impact on α-diversity and the induction of structural changes on soil bacterial community structure. Biochar did not affect root growth of hemp but significantly increased its aboveground biomass by ~1.67-fold for shoots, and by ~2-fold for both seed number and weight. Biochar increased the PTEs phytostabilisation potential of hemp with respect to Cd, Pb and Zn, and also stimulated hemp phytoextracting capacity with respect to Sb. Overall, the results showed that biochar can boost hemp yield and its phytoremediation effectiveness in soils contaminated by PTEs providing valuable biomass that can generate profit in economic, environmental and sustainability terms