Tantalum Dissolution Rate in Simulant Lung Fluid

The aim of this study is to determine the solubility rate of tantalum contained in pyrochlore, columbite–tantalite and columbite in simulant lung fluid. The International Commission on Radiological Protection (ICRP), in its recommendation for limiting intakes of radionuclide by workers, has consistently recognized that the biological behavior of any specific material after incorporation can significantly diverge from model prevision. Model parameters should be adjusted to adapt the model for each specific substance material in order to estimate the dose due to this element intake. The most recent ICRP publication 66, respiratory tract dosimetry model, point out that information as data like particle size, aerosols solubility and the material chemical compounds are important parameters in the dose coefficients calculation. This paper studies the solubility in Simulant Lung Fluid (SLF) of Ta present in mineral dust particles. For this study 3 minerals were selected: pyrochlore, columbite–tantalite and columbite. Tantalum dissolution in vitro samples were obtained using the Gamble solution and PIXE (Particle Induced X-ray Emission) as analytical technique. In order to characterize the worker exposure to Ta bearing particles, one Brazilian niobium mine was selected. The mineral dust particles were collected using a six-stage cascade impactor and the elemental mass concentrations and the MMAD (Mass Median Aerodynamic Diameter) were determined. Concentrations of radionuclides from natural series of thorium and uranium were also determined. The results show that the workers are exposed to Ta bearing particles in the respirable fraction of aerosols (aerodynamic diameter (d _aer) <2.5 μm) during the mineral processing to obtain Fe–Nb alloy. The solubility in Simulant Lung Fluid (SLF) of Ta present in mineral dust particles depends on the mineral characteristics. The solubility half-time varies between 34 and 62 h depending on the associated mineral.     

Preparation and characterization of durum wheat (Triticum durum) straw cellulose nanofibers by electrospinning

Cellulose nanofibers from durum wheat straw ( Triticum durum ) were produced and characterized to study their potential as reinforcement fibers in biocomposites. Cellulose was isolated from wheat straw by chemical treatment. Nanofibers were produced via an electrospinning method using trifluoroacetic acid (TFA) as the solvent. The nanofibers were 270 ± 97 nm in diameter. Analysis of the FT-IR spectra demonstrated that the chemical treatment of the wheat straw removed hemicellulose and lignin. XRD revealed that the crystallinity of the cellulose was reduced after electrospinning, but nanofibers remained highly crystalline. The glass transition temperature (T(g) value) of the fibers was 130 °C, higher than that of cellulose (122 °C), and the degradation temperature of the fibers was 236 °C. Residual TFA was not present in the nanofibers as assessed by the FT-IR technique.     

Soil pore-water environment and CO2 emission in a Luvisol as influenced by contrasting tillage

Little is known how contrasting tillage (deep ploughing, top- and sub-soil loosening with straight or bent leg cultivator [BLC], direct drilling [DD]) affect important soil physical properties (total porosity [TP], pore size distribution [PSD], water release characteristics [WRC]) and CO₂ emissions from a Luvisol. The study was aimed to alleviate compaction on land that had been under reduced tillage for 4 successive years. Undisturbed core samples were collected from 5–10, 15–20 and 25–30 cm depths for soil WRCs, TP and pore-size distribution determination. A closed chamber method was used to quantify the CO₂ emissions from the soil. Soil loosening with straight or BLC produced the highest total soil porosity (on average 0.48 m³ m^?3) within 5–30 cm soil layer, while conventional tillage (CT) gave 6%, DD up to 25% reduction. Sub-surface loosening with a BLC was the most effective tool to increase the amount of macro- and mesopores in the top- and sub-soil layers. It produced 21% more macro- and mesopores within 25–30 cm soil layer as compared to the soil loosened with a straight leg cultivator. Plant available water content under CT and DD was lower as compared to that under deep loosening with straight or BLC (23% and 18%, respectively). DD produced 12% lower soil surface net carbon dioxide exchange rate than CT and by 25–28% lower than deep soil loosening with straight or BLC. The increase in micropores within 25–30 cm soil layer caused net carbon dioxide exchange rate reduction. The amount of mesopores within the whole 5–30 cm soil layer acted as a direct dominant factor influencing net CO₂ exchange rate (NCER) (Pxy = ?3.063; r = 0.86).     

A transgenic RNAi approach for developing tomato plants immune to Pepino mosaic virus

RNA interference (RNAi) or gene silencing is a natural defence response of plants to invading viruses. Here, we applied this approach against pepino mosaic virus (PepMV) isolates in their natural host, tomato. PepMV isolates differ in their genetic sequences, the severity of the disease they induce, and their worldwide distribution. PepMV causes heavy crop losses, mainly due to impaired tomato fruit quality. Resistant varieties are not yet available, despite many years of resistance breeding efforts within the tomato seed industry. To generate broad resistance to PepMV strains, conserved sequences from three different strains of PepMV (US1, LP, and CH2) were synthesized as a single insert and cloned in a hairpin configuration into a binary vector, which was used to transform tomato plants. Transgenic tomato lines that expressed a high level of transgene-siRNA exhibited immunity to PepMV strains, including a new Israeli isolate. This immunity was maintained even after graft inoculation, in which a transgenic scion was grafted onto nontransgenic infected rootstocks. However, an immune transgenic rootstock was unable to induce resistance in a nontransformed scion. These results provide the first example of engineered immunity to diverse PepMV strains in transgenic tomato based on gene silencing.     

Astaxanthin and Its Esters in Pigmented Oil from Fermented Shrimp By-Products

ABSTRACT

This study focuses on the isolation and quantification of astaxanthin and its esters in the oils extracted from shrimp waste. The content of astaxanthin was determined by high performance liquid chromatography and ranged from 1.5 to 2.1 mg g^?1. The astaxanthin and its esters were isolated by thin layer chromatography in three fractions: free astaxanthin, monoester, and diester of astaxanthin, with percentages of 44, 32, and 26%, respectively. Oleic acid was the major fatty acid in the monoester fraction, while palmitic, oleic, and stearic acids were present predominantly in the diester fraction. Free radical-scavenging activity of the oils and the three fractions was evaluated. All oils showed an effect on the decrease in the absorbtion of 1,1-diphenyl-2-picrylhydrazyl solutions, while among the fractions no significant difference occurred. Pigmented oil from shrimp waste is an organic source of pigment and antioxidant astaxanthin, the esters, and fatty acids, such as eicosapentaenoic and docosahexaenoic.     

Soil sustainability changes in organic crop rotations with diverse crop species and the share of legumes

There have been few long-term field studies on greenhouse gases measurement in organic crop rotations under temperate climatic conditions. Little is known about the extent to which the share of legumes in a crop rotation of organic farming affects the potentials for CO₂ emission and soil organic carbon sequestration. The current study was aimed to investigate soil physicochemical state and soil net CO₂ exchange rate in diverse organic crop rotations with different crop species and proportions of legumes. Four 5-year duration crop rotations were investigated. The best soil sustainability of the arable layer was found in a crop rotation enriched with red clover (Trifolium pratense L.). This rotation resulted in the highest soil mesoporosity and the lowest microporosity, ensured the best supply of plant-available water and revealed high soil resistance to dry conditions. Red clover secured the highest soil organic C sequestration, caused the increase in reserves of total N and available K, and slackened the decrease of soil-available P sources. Red clover-based cropping system exhibited the highest soil net CO₂ exchange rate during five experimental years. The effect of crop rotation, consisting of phacelia (Phacelia tanacetifolia Benth.), peas (Pisum sativum L.) and yellow lupin (Lupinus luteus L.), on soil sustainability was weaker than the effect of rotation with red clover. Non-legume rotations, i.e. binary (two-crop) rotation and the crop rotation involving four spring and one winter species, can be regarded as miners of soil nutrient resources rather than contributors. These rotations did not promote soil sustainability because the soil lost large amounts of macronutrients and caused 26–33% lower soil net CO₂ exchange rate, compared with leguminous rotations. For future, it could be recommended for ecological farming to rely more on crop rotations with red clover to improve ecosystems functioning.     

Ilyonectria palmarum sp. nov. causing dry basal stem rot of Arecaceae

During surveys conducted in 2010–2013, a complete breakage or bending of the trunk and a dry basal stem rot were observed on containerised Brahea armata, B. edulis, Howea forsteriana and Trachycarpus princeps plants in different nurseries located in eastern Sicily (southern Italy). A cylindrocarpon-like species was consistently obtained from diseased palm tissues, while known pathogens of these hosts such as Ganoderma, Phytophthora and Thielaviopsis were not found associated with symptomatic tissues or isolated on standard or selective media. A total of 40 cylindrocarpon-like isolates were collected and characterised based on morphology and DNA phylogeny. Multigene analyses based on the β-tubulin, histone H3, translation elongation factor 1-α, and the internal transcribed spacers (ITS1, 5.8S, ITS2) genes facilitated the identification of a new species, described here as Ilyonectria palmarum. The pathogenicity of one representative isolate collected from each palm species was tested on plants cultivated under nursery conditions and in a growth chamber. All isolates were pathogenic to B. armata, B. edulis, H. forsteriana, and T. princeps and symptoms identical to that observed in nurseries were reproduced. Dry basal stem rot and stem bending caused by Ilyonectria palmarum represents a potentially serious problem for nurseries cultivating containerised palms.     

Occurrence and characterisation of <Emphasis Type="Italic">Rhizoctonia</Emphasis> species causing diseases of ornamental plants in Italy

During surveys conducted in 2010–2012 Rhizoctonia symptoms were observed on 30 ornamental species in different nurseries located in eastern Sicily (Southern Italy). Eighty-eight isolates of Rhizoctonia spp. were obtained from symptomatic leaves, roots and stems. Fifty-six of the isolates were binucleate and 32 were multinucleate Rhizoctonia. Characterisation of anastomosis groups (AGs) was performed using morphological characteristics and sequence analysis of the internal transcribed spacer of ribosomal DNA ( rDNA-ITS) region. Most isolates collected were Rhizoctonia solani AG-4 HG-I (35.2% of all isolates) and one isolate was AG-2-2 IIIB. The binucleate isolates belonged to AG-R (27.3%), AG-A (21.6%), AG-G (12.5%), AG-V (1.1%) and AG-Fb (1.1%). The pathogenicity of 38 representative isolates collected from each host was tested on seedlings or cuttings grown in a growth chamber. All R. solani AG-4 HG-I isolates, most of the binucleate AG-R, AG-A and AG-G and AG-V were pathogenic and reproduced symptoms identical to that observed in nurseries, while binucleate AG-Fb and R. solani AG-2-2 IIIB isolates were nonpathogenic. This is the first report of the occurrence of Rhizoctonia species on some ornamental plants and the first report of binucleate Rhizoctonia AG-R and AG-V in Europe.     

Relationship between spring triticale physiological traits and productivity changes as affected by different N rates

There is still a lack of knowledge about the physiological traits of spring triticale (x Triticosecale Wittm.) and their relationship with grain yield and protein content under the conditions of the environmental Zone Nemoral 2. The objective of this study was to determine the relationships among the physiological indices, grain yield and protein content as affected by nitrogen (N) rates. The correlation among leaf area index (LAI), chlorophyll index (SPAD), canopy greenness index (CGI), leaf area duration (LAD) and grain yield as well as direct and indirect effects of those traits on the yield were investigated using a path analysis. Grain yield, protein content and physiological indices were significantly (P?≤?.01) affected by N fertilization. N₉₀ level was the best compromise for the yield and physiological indices. The interaction of all physiological indices influenced the grain yield by 27–39%, protein by 42–44%. SPAD and LAI had greater influence on grain yield and grain protein than CGI and LAD. SPAD had positive direct dominant (the highest) effect on the yield only at BBCH 59 and BBCH 69 (50% of the tested cases). LAI was responsible for 19–39% of the correlation between yield and physiological indices. The physiological indices can be used for spring triticale growth modelling and agronomic management for improved productivity and grain quality. SPAD and LAI values, established at BBCH 45–69, can be used for grain yield prediction and those estimated at BBCH 69 can be used for grain protein prediction.

Abbreviations BBCH: Biologische Bundesantalt, Bundessortenamt und Chemische Industrie (decimal system for a uniform coding of phenologically similar growth stages of all mono- and dicotyledonous plant species); CGI: canopy greenness index; GS: growth stage; LAD: leaf area duration; LAI: leaf area index; SPAD: chlorophyll index (soil plant analysis development)