Pore‐size distribution and particle arrangement in fragipan and nonfragipan horizons

Fragipan is a widely distributed subsoil horizon that induces severe limitations to plant growth and land use, mainly because of its high bulk density. In this work, we evaluated the pore‐size distribution through the analysis of the cumulative curve of intruded mercury volume in some soils with fragipan horizons. This approach provides information also about the arrangement of particles, thus we compared the results obtained for fragipan and nonfragipan horizons to relate porosity and particle arrangement with the specific physical properties of fragipans. The total volume of intruded mercury did not allow to discriminate between fragipan and nonfragipan horizons. However, from the variation of the pore volume as a function of the radius, two modal classes of pores were found, coarse and fine, respectively. The fine‐pore class arose from the arrangement of clay particles, and its volume was correlated to clay contents (r = 0.787) and to clay packing density (r = –0.621). The clay fractions in fragipans were less densely packed than in the other B horizons, even if they had similar clay contents. The coarser‐pore modal class is known to arise from the interactions between clay, silt, and sand particles, and its volume was different among horizons. Fragipan had a low volume of this modal pore class. In addition, a packing density for the coarser phase of 0.74, corresponding to a rhombohedral packing, was found only in fragipans. Thus, the low permeability and high bulk density of fragipans are linked to specific arrangements of the particles: an open packing of the clay phase is associated to an extremely dense packing of silt and sand. This combination is not present in any other soil horizon.     

Bimetallic blends and chitosan nanocomposites: novel antifungal agents against cotton seedling damping-off

Anthracnose disease caused by fungal pathogen Colletotrichum capsici is considered to be one of the most destructive diseases in chilli cultivation as it infects and leads to complete destruction of the crop by infecting the mature fruit in the field and/or during the storage period. The management of the disease is difficult due to the absence of any resistant cultivar and effective fungicide. The current study was initiated to evaluate the antifungal efficacy of the biosurfactant produced by strain Pseudomonas aeruginosa JS29 for biological control of anthracnose disease. The results revealed significant disease reduction using biosurfactant in plant assay which were challenge-inoculated with the fungal spore. In vitro experiments clearly showed that the biosurfactant can effectively inhibit the growth of both spore and mycelia of the pathogen. Moreover, the biosurfactant can also effectively inhibit the fungal growth in detached-fruit assay in different storage conditions. The study confirmed that the biosurfactant has tremendous potential to become a viable, cost-effective and environment-friendly alternative for managing anthracnose disease in field and in post-harvest storage condition.     

N<Subscript>2</Subscript>O,CO<Subscript>2</Subscript>, Production,and C Sequestration in Vineyards: a Review

Even if it is less polluting than other farm sectors, grape growing management has to adopt measures to mitigate greenhouse gas (GHG) emissions and to preserve the quality of grapevine by-products. In viticulture, by land and crop management, GHG emissions can be reduced through adjusting methods of tillage, fertilizing, harvesting, irrigation, vineyard maintenance, electricity, natural gas, and transport until wine marketing, etc. Besides CO₂, nitrous oxide (N₂O) and methane (CH₄), released from fertilizers and waste/wastewater management are produced in vineyards. As the main GHG in vineyards, N₂O can have the same harmful action like large quantities of CO₂. Carbon can be found in grape leaves, shoots, and even in fruit pulp, roots, canes, trunk, or soil organic matter. C sequestration in soil by using less tillage and tractor passing is one of the efficient methods to reduce GHG in vineyards, with the inconvenience that many years are needed for detectable changes. In the last decades, among other methods, cover crops have been used as one of the most efficient way to reduce GHG emissions and increase fertility in vineyards. Even if we analyze many references, there are still limited information on practical methods in reducing emissions of greenhouse gases in viticulture. The aim of the paper is to review the main GHG emissions produced in vineyards and the approached methods for their reduction, in order to maintain the quality of grapes and other by-products.     

Nodular presentation of Dirofilaria repens infection in a cat mimicking a fibrosarcoma

A cat with multiple subcutaneous nodules suggesting a soft tissue sarcoma by physical and computed tomographic examination was diagnosed as being affected by subcutaneous filariosis based on cytologic and ultrasonographic assessments. Nodules were surgically removed and extracted nematodes were identified by PCR as Dirofilaria repens. Furthermore, DNA of Dipetalonema dracunculoides (syn. Acantocheilonema dracunculoides) was detected by PCR, with no evidence of circulating microfilariae. To the best of the authors' knowledge, this represents the first report describing adults of D repens in multiple subcutaneous nodules in a cat. Cytopathologic examination allowed characterization of the parasitic nature of the nodules. Veterinary practitioners should be aware of the possible nodular presentation of D repens in cats and should include D repens in the differential diagnosis of subcutaneous neoformations in the cat.     

Brucella abortus INTA2, a novel strain 19 (Delta)bp26::luc (Delta)bmp18 double mutant lacking drug resistance markers

Brucella abortus INTA2, a novel mutant strain, was constructed by inactivation of two B. abortus S19 genes: bp26 and bmp18, with the objective of obtaining a mutant strain that could be compatible with a diagnostic test and have less residual virulence than strain 19. The double mutant was constructed by replacing a large section of the bp26 coding region with the luciferase (luc) coding gene, resulting in mutant strain B. abortus M1luc, followed by partial deletion of bmp18 coding sequence. Both genes were inactivated by allelic replacement assisted by sacB counter-selection. Luciferase expression was evaluated and confirmed that it is a valid marker in the construction of mutant strains. When B. abortus INTA2 was inoculated in BALB/c mice, significantly fewer colony forming units (CFUs) were recovered from mice spleens during initial phase of infection. No splenomegaly was observed in strain INTA2-immunized mice at any time suggesting that strain INTA2 has lost some residual virulence of the parental strain. Nevertheless, similar protection levels against virulent challenge were observed in mice immunized with strains INTA2 or S19. Although strain INTA2 would still induce O-side antibodies, it does not express BP26. This would allow differentiation of INTA2-vaccinated animals from animals infected with field strains by measuring anti-BP26 antibodies, either by an agglutination test or ELISA using BP26 as antigen. Altogether these results indicate that B. abortus INTA2 might be a promising vaccine strain against brucellosis.     

Biostimulation of Soil Microbial Activity Through Organic Fertilizer and Almond tree Association

Many studies have confirmed the validity of plant cover and organic farming in ameliorating soil quality. The goal of this study was to investigate the efficiency of rehabilitation practices in a degraded soil ecosystem consisting of: (i) organic or inorganic fertilization; and (ii) presence or absence of almond trees. The experiments were carried out for 2 years in the South of Italy in three fields characterized by different slope (0%, 2%, and 6%). Each field was split up into two parts, one assigned to organic fertilization and the other assigned to mineral fertilization, and planted with almond trees using GF677 or Franco rootstocks. The results showed that the organic fertilization, particularly in the presence of the Franco rootstock, resulted more effective in increasing soil organic matter content and microbial activity especially in the 0% and 2% slopes. However, in the 6% slope, where a lower soil metabolism was observed, an improvement of chemical and biochemical soil properties was generally evident for both fertilization systems. The Franco rootstock improved soil quality and maintaining a good production, whereas the GF677 has exploited more soil resources, resulting in a higher growth and yield; therefore, the use of almond tree with Franco rootstock associated with organic matter application is a useful practice in order to preserve soil quality and to rehabilitate degraded soils. Copyright © 2013 John Wiley & Sons, Ltd.     

Fumigant bioactivity of five Citrus essential oils against Tribolium confusum

During the past decades, the huge use of pesticides caused several environmental problems, so research investigations moved to find a series of compounds with selective toxicity, of a biodegradable and environment-friendly nature, maintaining a positive action in crop and stored products protection. In this perspective, interesting results in the control of pests and fungal pathogens were obtained using essential oils, which are compounds produced by many species of plants as secondary metabolites. The purpose of this research was to evaluate the fumigant activity of five Citrus essential oils against the confused flour beetle Tribolium confusum Du Val, planning a possible employment in the mill industry. The fumigant effectiveness was evaluated 24, 48, 72 hours and 7 days after the start of exposure and each essential oil was analyzed by means of GC and GC/MS. Further evaluations about the toxicity of these compounds were made by partially filling the glass vials with food matrix, in order to assess the possible interference of this matter on the active compounds. The data obtained indicated that, at a low level of fumigant concentration, essential oils can effectively control stored product pests; in the presence of debris, like flour, the efficacy decreased. Plant extracts caused also increased mortality levels after the end of fumigation. The results obtained from this experimentation confirm the efficacy of essential oils in pest control and, in particular, against stored product pests.     

Potential Biomedical Applications of Collagen Filaments derived from the Marine Demosponges Ircinia oros (Schmidt, 1864) and Sarcotragus foetidus (Schmidt, 1862)

Collagen filaments derived from the two marine demosponges Ircinia oros and Sarcotragus foetidus were for the first time isolated, biochemically characterised and tested for their potential use in regenerative medicine. SDS-PAGE of isolated filaments revealed a main collagen subunit band of 130 kDa in both of the samples under study. DSC analysis on 2D membranes produced with collagenous sponge filaments showed higher thermal stability than commercial mammalian-derived collagen membranes. Dynamic mechanical and thermal analysis attested that the membranes obtained from filaments of S. foetidus were more resistant and stable at the rising temperature, compared to the ones derived from filaments of I. oros. Moreover, the former has higher stability in saline and in collagenase solutions and evident antioxidant activity. Conversely, their water binding capacity results were lower than that of membranes obtained from I. oros. Adhesion and proliferation tests using L929 fibroblasts and HaCaT keratinocytes resulted in a remarkable biocompatibility of both developed membrane models, and gene expression analysis showed an evident up-regulation of ECM-related genes. Finally, membranes from I. oros significantly increased type I collagen gene expression and its release in the culture medium. The findings here reported strongly suggest the biotechnological potential of these collagenous structures of poriferan origin as scaffolds for wound healing.