Istituto Sperimentale Agronomico

The taxonomic characteristics of two bacterial strains, RB-8(T) and RB-9, isolated from hydrocarbon-degrading enrichment cultures obtained from Antarctic coastal marine environments (Rod Bay, Ross Sea), were determined. These bacteria were psychrophilic, aerobic and Gram-negative with polar flagella. Growth was not observed in the absence of NaCl, occurred only at concentrations of Na+ above 20 mM and was optimal at an NaCl concentration of 3-5% (w/v). The major cellular fatty acids were monounsaturated straight-chain fatty acids. The strains were able to synthesize the polyunsaturated fatty acid eicosapentaenoic acid (20: 5omega3) at low temperatures. The DNA G + C contents were 41-42 mol%. The strains formed a distinct phyletic line within the gamma-Proteobacteria, with less than 89.6% sequence identity to their closest relatives within the Bacteria with validly published names. Both isolates exhibited a restricted substrate profile, with a preference for aliphatic hydrocarbons, that is typical of marine hydrocarbonoclastic micro-organisms such as Alcanivorax, Marinobacter and Oleiphilus. On the basis of ecophysiological properties, G + C content, 16S rRNA gene sequences and fatty acid composition, a novel genus and species within the gamma-Proteobacteria are proposed, Oleispira antarctica gen. nov., sp. nov.; strain RB-8(T) (= DSM 14852(T) = LMG 21398(T)) is the type strain.

This paper investigates the relationship between C-band backscatter measurements and wheat biomass and the underlying soil moisture content. It aims to define strategies for retrieval algorithms with a view to using satellite C-band synthetic aperture radar (SAR) data to monitor wheat growth. The study is based on a ground-based scatterometer experiment conducted on a wheat field at the Matera site in Italy during the 2001 growing season. From March to June 2001, eight C-band scatterometer acquisitions at horizontal-horizontal and vertical-vertical polarization, with incidence angles ranging from 23/spl deg/ to 60/spl deg/, were taken. At the same time, soil moisture, wheat biomass, and canopy structure were collected. The paper describes the experiment and investigates the radar sensitivity to biophysical parameters at different polarizations and incidence angles, and at different wheat phenological stages. Based on the experimental results, the retrieval of wheat biomass and soil moisture content using Advanced Synthetic Aperture Radar data is discussed.

An international initiative aimed at the harmonization and validation of existing and future land cover datasets is needed to support operational earth observation of land. The goal is to overcome current limitations of land cover datasets with respect to their compatibility and comparability and unknown accuracy. These limitations significantly hinder a variety of applications. Key entities in this effort are the Land Cover Implementation Team of Global Observation of Forest Cover/Global Observation of Land Dynamics, the Global Land Cover Network, and the CEOS Group on Calibration and Validation. In their recent efforts, they have explored and provided the methodological and organizational resources to foster such an international cooperation. The approaches described in this paper include an introduction of the UN Land Cover Classification System as a common land cover language and a basis for legend translation. All actors involved in land cover mapping are invited to participate in this initiative.

Abstract Although root architecture has been shown to play an important role in crop performance, particularly under drought conditions, no information is available on the genetic control of root traits in durum wheat, a crop largely grown in rainfed areas with low rainfall. In our study, a panel of 57 elite durum wheat accessions were evaluated under controlled conditions for root and shoot traits at the seedling stage. Significant genetic variability was detected for all the root and shoot traits that were investigated. Correlation analysis suggested that root and shoot features were only partially controlled by common sets of genes. The high linkage disequilibrium (up to 5 cM) present in the germplasm collection herein considered allowed us to use simple sequence repeat‐based association mapping to identify chromosome regions with significant effects on the investigated traits. In total, 15 chromosome regions showed significant effects on one or more root architectural features. A number of these regions also influenced shoot traits and, in some cases, plant height measured in field conditions. Major effects were detected on chromosome arms 2AL (at Xgwm294 ), 7AL (at Xcfa2257 and Xgwm332 ) and 7BL (at Xgwm577 and Xcfa2040 ). The accessions with the most remarkable differences in root features will provide a valuable opportunity to assemble durum wheat mapping populations well suited for ascertaining the effects of root architecture on water use efficiency and grain yield.

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 212:1-12 (2001) - doi:10.3354/meps212001 Spatial variability and human disturbance in shallow subtidal hard substrate assemblages: a regional approach Simonetta Fraschetti1,*, C. Nike Bianchi2, Antonio Terlizzi1, Giovanni Fanelli3, Carla Morri4, Ferdinando Boero1 1Dipartimento di Biologia, Stazione di Biologia Marina di Porto Cesareo, CoNISMa, Università di Lecce, 73100 Lecce, Italy 2Marine Environmental Research Centre, ENEA Santa Teresa, PO Box 316, 19100 La Spezia, Italy 3Istituto Sperimentale Talassografico del CNR ŒA. Cerruti¹, Via Roma 4, 74100 Taranto, Italy 4DipTeRis, Dipartimento per lo studio del Territorio e delle sue Risorse, Università di Genova, Corso Europa 26, 16132 Genoa, Italy *E-mail: sfrasca@ilenic.unile.it ABSTRACT: Quantitative information about spatial patterns in subtidal hard substrate assemblages is scant. Such information is necessary to understand the responses to anthropogenic disturbances in these habitats. Along the coast of Apulia (Southern Italy), the collection of the European date mussel Lithophaga lithophaga is a strong source of disturbance: harvesting is carried out by demolition of the rocky substrate and causes epibiota disappearance. A hierarchical sampling design was used to quantify the spatial variability of subtidal epibenthic assemblages and the extent of rock damage due to L. lithophaga harvesting along 360 km of rocky coasts in Apulia. The surveyed coast was divided into 8 adjacent sectors, and replicate samples were taken by visual inspection at each of the 3 sites nested in each sector. Multivariate analyses indicated that assemblages differed consistently with spatial scale, variability being higher at the largest scale. However, variability among sites within each sector was also detected. Patchiness (i.e., average similarity among quadrats) was consistent among sectors. Some species were identified as Œimportant¹ in characterising and/or differentiating sectors. The pattern of distribution of these species as well as total cover and number of species were analysed by analysis of variance. Results recorded a considerable source of variation at site level. Damage by L. lithophaga fishing was shown to be extremely widespread. A humped relationship between patchiness and disturbances by L. lithophaga fisheries was obtained. In particular, patchiness at a small scale was highest at Œintermediate¹ levels of damage, because disturbance produces patches of different size and/or age, leading to Œmosaic¹ landscapes of epibenthic assemblages. KEY WORDS: Subtidal assemblage · Spatial scale · Human disturbance · Rocky substrate · Lithophaga lithophaga · Mediterranean Sea Full text in pdf format NextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 212. Online publication date: March 08, 2001 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2001 Inter-Research.

BACKGROUND: Development rates of Aedes aegypti are known to vary with respect to many abiotic and biotic factors including temperature, resource availability, and intraspecific competition. The relative importance of these factors and their interactions are not well established across populations. We performed meta-analysis on a dataset of development rate estimates from 49 studies. RESULTS: Meta-analytic results indicated that the environmental factor of temperature is sufficient to explain development rate variability in Ae. aegypti. While diet and density may greatly impact other developmental phenotypes, these results suggest that for development rate these factors should never be considered to the exclusion of temperature. The effect of temperature on development rate is not homogenous or constant. The sources of heterogeneity of the effect of temperature are difficult to analyze due to lack of consistent reporting of larval rearing methods. CONCLUSIONS: Temperature is the most important ecological determinant of development rate in Ae. aegypti, but its effect is heterogeneous. Ignoring this heterogeneity is problematic for models of vector population and vector-borne disease transmission.

Producing specific varieties for each subregion of a target region, instead of widely adapted varieties, may exploit positive genotype × location (GL) interactions to increase crop yields. With reference to the Algerian durum wheat ( Triticum durum Desf.) region, as defined in a Geographic Information System (GIS), this study aimed at (i) comparing additive main effects and multiplicative interaction (AMMI) vs. joint regression modeling of GL effects, (ii) verifying the reliability of a GIS‐based definition of two subregions that extended the site classification on the basis of GL effects as a function of long‐term winter mean temperature in the GIS, and (iii) comparing wide vs. specific adaptation in terms of observed and predicted yield gains (the latter for scenarios of defined and undefined selection locations). Twenty‐four cultivars from international centers, Europe, and North Africa were evaluated across 3 yr in a total of 47 environments by randomized complete block designs with four replications per trial. The AMMI modeling was distinctly superior to joint regression. The AMMI + cluster analysis and pattern analysis classified test locations consistently and in good agreement with the GIS‐based subregion definition. Under the hypothesis of six selection environments assigned to subregions in proportion to their size (three sites in each of two years) for late stage selection, specific adaptation provided 2 to 7% greater gains than wide adaptation over the region at similar costs. The advantage of specific adaptation was much larger (39% determined on the basis of observed gains) for the smaller, stressful inland subregion, where specific adaptation may also enhance food security. Performing earlier specific selection, or adopting distinct genetic bases for each subregion, may further increase the advantage of specific breeding.

The seasonal composition of phytoplankton communities was investigated in a Mediterranean brackish area (Varano lagoon). Twelve stations were sampled monthly from March 1997 to February 1998. Numbers of prokaryotic and eukaryotic picophytoplankton cells were estimated by epifluorescence microscopy, while larger phytoplankton (nano and micro fractions) were enumerated by the Utermöhl settling technique. Picophytoplankton densities ranged from 0.7 to 448.6 cells × 106 l–1. Nano- and microphytoplankton abundances varied between 0.2 and 7.9 cells × 106 l–1. The picoplankton fraction was represented mainly by cyanobacteria and the Utermöhl fraction by nano-sized phytoflagellates (56.2%) and diatoms (20.1%). The phytoflagellates had a greater abundance over time while diatoms reached the highest densities in summer and fall. In Varano lagoon, phytoplankton development is related to ‘nitrogen-poor' waters and to phosphorus availability. Suspension-feeding bivalves (Mytilus galloprovincialis) are sufficiently abundant to filter a volume equivalent to the volume of Varano lagoon at least once daily. These observations suggest that grazing exerts an important influence on phytoplankton dynamics, mainly on the micro fraction, and that diatoms seem to play an important role in the food web dynamics of this coastal fishery.

The reactivity of industrially relevant silylalkylamines towards CO2 and dialkyl/arylcarbonates is discussed. The kinetics of uptake of carbon dioxide at various temperatures shows that at 295 K, silylalkylmonoamines react with carbon dioxide in a 2∶1 molar ratio, affording classic intermolecular ammonium carbamates of formula RNHCOO−+NH3R, while at 273 K, dimeric carbammic acids, (RNHCOOH)2, are formed. Conversely, silylalkyldiamines react at 297 K with carbon dioxide to afford zwitterionic intramolecular six-membered cyclic ammonium carbamates of formula RNH2+CH2CH2NHCOO−, a unique example of CO2 uptake by an amine with a 1∶1 molar ratio. Such systems may have a potential application in CO2 separation. The catalytic role of carbon dioxide in the carbamation of the above mentioned amines by reaction with organic carbonates is described.

International audience

AbstractAgronomic value and environmental impact of two composts were evaluated in a three-year field experiment (2002, 2003 and 2004) on alfalfa and cocksfoot in Southern Italy. The effects of Municipal Solid Waste compost (MSW), Olive Pomace Compost (OPC), mineral fertilizer (Min) (phosphorus as 75 kg ha−1 for alfalfa and nitrogen as 50 kg ha−1 for cocksfoot) and an unfertilized treatment (Contr) were compared on crop yield, soil characteristics and environment impact. During the cropping cycles, fresh and dry weights, plant nitrogen status (leaves SPAD readings and petiole nitrate content) and plant total N content were determined for calculating the protein content and the plant N uptake. Moreover, at the beginning and the end of the research, chemical soil characteristics and heavy metal levels were also determined. The results indicated that in cocksfoot fertilized with MSW and OPC composts, the mean cumulative dry weight increased by 20.85 and 16.51%, respectively compared to the control, but it was significantly lower than Min treatment. In the alfalfa crop, the mean cumulative dry weight of Control, MSW and OPC treatments were very similar and lower than mineral fertilizer (−7.86, −7.09 and −10.31%, respectively). At the end of the experiment, (2004) the soil total N increased significantly in alfalfa (from 1.32 to 1.45 g kg−1) while no significant difference was found for the cocksfoot. After three years of compost application, the total soil organic carbon increased significantly in both crops (23.98% for cocksfoot, and 43.17% for alfalfa in respect to the control), indicating that MSW and OPC amendments positively affected the organic matter. Furthermore, total organic carbon (in both crops) and humified organic carbon (in alfalfa) were significantly lower in the Contr treatment than on the MSW and OPC treatments.

Abstract The hydromedusan subumbrellar muscle tissues originate from a mass of endo‐ and ectoderm derived cells proliferating inwardly. This mass of cells, called entocodon, is separated by the ecto‐and endoderm through a layer of extracellular matrix, thus forming a locally triploblastic arrangement of tissues. By cavitation and differentiation, the entocodon gives rise to the striated and smooth muscle layers of the subumbrella. The structure of the striated muscle is histologically identical to that described for triploblasts, where striated muscle is mainly mesodermic. Together with the mode of development, this suggests that not all Cnidaria are diploblastic and that the subumbrellar cavity is a coelom‐like structure. The subumbreHar cavity is formed late in ontogeny, whereas the coelom in higher animals is normally formed during embryonic development. Instead of remaining closed, the subumbrella becomes open, with the muscular mesothelium in contact with the environment. This view of cnidarian structures can be pushed further while considering the regulation of modularity and metamery. The occurrence of homeotic genes in cnidarians and other ‘lower’ animals shows that the specification of body architecture has a common molecular ground throughout the animal kingdom. It is suggested that the expression of homeotic genes while specifying a given architecture might be regulated by iteration of their activity, leading to ‘low’ modular organisms and to ‘higher’ metameric ones. Replicated parts as modules and metameres might be analogous, but the affinity in their molecular specification (and possibly regulation) might indicate homology. The number of resemblances between cnidarians and ‘higher’ metazoa suggests that this phylum might be a centre of metazoan radiation, having structures which represent the living premises of the main steps of animal evolution.

Cholesterol distribution in tumoral tissues and lipid composition in the plasma compartment were determined in patients affected by different histologic types of lung cancer. The results showed that tumoral lung tissues contained 2-fold more total cholesterol and 3.5-fold more esterified cholesterol than normal lung tissues. In the patients the alterations in intracellular cholesterol were also associated with peculiar changes in cholesterol distribution in the plasma compartment. Serum high-density lipoprotein (HDL) cholesterol levels were markedly lower in than in controls. No significant changes in other lipid parameters were observed in these patients. We suggest that the reduced levels of serum HDL cholesterol observed in patients with lung tumors may be a consequence of the disease, probably mediated by the greater utilization of cholesterol for new membrane biogenesis and by the accumulation of esterified cholesterol in tumoral tissues.

Four 1 km global land cover products are currently available to the scientific community: the University of Maryland (UMD) global land cover product, the International Geosphere–Biosphere Programme Data and Information System Cover (IGBP‐DISCover), the MODerate resolution Imaging Spectrometer (MODIS) global land cover product and Global Land Cover 2000 (GLC2000). Because of differences in data sources, temporal scales, classification systems and methodologies, it is important to compare and validate these global maps before using them for a variety of studies at regional to global scales. This study aimed to perform the validation and comparison of the four global land cover datasets, and to examine the suitability and accuracy of different coarse spatial resolution datasets in mapping and monitoring cropland across China. To meet this objective, we compared the four global land cover products with the National Land Cover Dataset 2000 (NLCD‐2000) at three scales to evaluate the accuracy of estimates of aggregated cropland areas in China. This was followed by a spatial comparison to assess the accuracies of the four products in estimating the spatial distribution of cropland across China. A comparative analysis showed that there are varying levels of apparent discrepancies in estimating the cropland of China between these four global land cover datasets, and that both area totals and spatial (dis)agreement between them vary from region to region. Among these, the MODIS dataset has the best fit in depicting China's croplands. The coarse spatial resolution and the per pixel classification approach, as well as landscape heterogeneity, are the main reasons for the large discrepancies between the global land cover datasets tested and the reference data.

Understanding how growth and development of grain sorghum [ Sorghum bicolor (L.) Moench] genotypes respond to water limitation would provide a basis to assess the value of such responses in crop production and crop improvement. We conducted a greenhouse experiment to quantify responses of six genotypes to five levels of water limitation between floral initiation and flowering achieved by daily watering to weight. At flowering, the thermal time, biomass, height, water transpired, and transpiration efficiency (biomass/water transpired) were recorded. Results for water‐limited treatments were expressed relative to the well‐watered treatment. Degree of water limitation was indexed by calculating the ratio of the amount of water transpired in water‐limited treatments to that in the well‐watered treatment. This transpiration ratio decreases from a value of one as degree of water limitation increases. Under well‐watered conditions, genotypes differed significantly in thermal time and biomass, but not in height. Differences in biomass were related to differences in both water transpired and transpiration efficiency. The least efficient genotype had a value of transpiration efficiency 25% lower than that of the most efficient. Under water‐limiting conditions, relative thermal time increased at transpiration ratios < 0.55; genotypes did not differ. Relative height decreased linearly with transpiration ratio, and genotypes did not differ. Relative biomass decreased with increasing water limitation, but genotypes differed. This was related to genotypic differences in relative transpiration efficiency for transpiration ratios < 1. Some genotypes increased transpiration efficiency 28% under water limitation. The value of expressing water limitation as transpiration ratio and possible mechanisms explaining these findings are discussed.

In San Biagio of Belpasso, approximately 20 km south of Mt. Etna, in the area of contact between volcanic and sedimentary formations, a number of small (3- 60 cm in diameter) active mud eruptions discharge CO2-rich gases, mud and NaCl brines. They can be described as mini-volcanoes owing to their typical conic shapes and continuously bubbling peak craters. Samples were collected from the active peak craters at a depth of 20 cm and DNA was immediately extracted and amplified with universal 16S rRNA gene-specific primers, followed by cloning procedure. A total of 140 bacterial clones obtained were screened and clustered by restriction fragment length polymorphism (RFLP) analysis. The pool of 16S rRNA sequences representing each RFLP cluster was subjected to phylogenetic analysis. All of the 33 sequences analysed were affiliated with the kingdom of Eubacteria; 28 sequences (77% of all clones) affiliated with the Proteobacteria, two sequences (19% of all clones) were affiliated with Actinobacteria and three sequences (4% of all clones) were affiliated with the Flexibacter-Cytophaga-Bacteroides division. The data obtained suggest that the microorganisms phylogenetically affiliated to autotrophic methane oxidizers and heterotrophic hydrocarbon degraders belonging to the gamma-subclass of Proteobacteria are major constituents of the microbial communities of the saline volcanic muds. Overall, the composition of the microbial community of the San Biagio mud volcano resembles the compositions of marine microbial communities, which might indicate that wind-blown seawater vapour acted as an inoculum for microbial community described in present work.

ABSTRACT A two-year field study examined the effect of different sources of nitrogen (N) fertilization, soil tillage depths, and crop rotations on winter wheat yield, quality, and N utilization. Nitrogen fertilization treatments were: mineral N at 100 kg N ha−1 (Nmin); municipal solid waste compost at 100 kg N ha−1 of organic N (Ncomp); 50 kg N ha−1 of both compost and mineral N fertilizer (Nmix); unfertilized control (control). Tillage treatments were conventional and minimum tillage applied on the rotations tomato—wheat, sugar beet—wheat, and sunflower—wheat. The Nmix treatment had the highest yield and N uptake (5.29 t ha−1 and 157.9 kg ha−1, respectively). The partial substitution of mineral with organic N fertilizer increased yield by 8% and 33%, and N uptake by 2% and 31%, with respect to Nmin and control treatments, respectively. In comparison with Nmin, Nmix had a higher stability in these parameters throughout years and rotations, and no reduction in grain protein level and in N utilization. Conversely, the Ncomp performance was lower than Nmin and Nmix treatments, and the grain yield was only 12% higher than the control. Tillage affected yield and N uptake only in the year characterized by high rainfall during the vegetative stages, while no significant differences were found in protein content and N utilization in both years. Among the crop rotations, wheat after sugar beet had the highest grain yield (4.91 t ha−1) and a good protein content (11.9%), while sunflower and tomato rotations had a lower grain yield (4.35 t ha−1) and protein content (10.3%).

The gonyaulacoid dinoflagellate Alexandrium taylori Balech is reported for the first time from Italian waters. In July 1997, nonmotile stages of this species, both temporary and sexual resting cysts, were found in surface Ionian coastal waters (Mediterranean Sea) producing localized brownish‐yellow patches. Clonal cultures were established, and the life history of A. taylori was studied in the laboratory. Asexual reproduction took place during a motile phase and produced two daughter cells remaining temporarily attached in pairs. This species exhibited isogamy. Small gametes were produced from vegetative cells through the release of a division cyst and multiple fission of the protoplast. Isogametes from the same clonal strain fused and underwent sexual reproduction, forming planozygotes that subsequently developed storage bodies and dark pigmentation. The maturation of the planozygote into hypnozygote also involved an increase in size and final shedding of flagella and theca. Hypnozygotes germinated within 15 days of their formation, and a naked planomeiocyte emerged from the archeopyle to undergo successive divisions and reestablish a haploid motile population.

The application of statistical models on a time series of data arising from the MEDITS International Trawl Survey, an experimental demersal resources survey carried out during six years (1994-1999) in the same season of the year (late spring - early summer) using the same fishing gear in a large part of the Mediterranean, has allowed for a study to compare, for the first time, the space-time distribution, abundance, and size structure of the two Aristeids Aristaeomorpha foliacea and Aristeus antennatus throughout most of the Mediterranean Sea. This research has shown a large variability among the six reference areas, that were arbitrarily defined within the basin. In particular the two shrimps do not seem to present any correlation or yield continuity in the years. The same lack of homogeneity was also observed in the time trend of the abundances and frequencies of each of the two species. These data seem to confirm the intrinsic variability of the species, the cause of which is still unknown and undocumented. Nevertheless, a longitudinal gradient of catches has been observed where A. antennatus is more abundant in the west and A. foliacea in the east of the basin.

A study of the reproductive biology of the amberjack, Seriola dumerilii, held in captivity was carried out, describing oogenesis as well as the different stages of the ovarian cycle. Seven stages of oocyte development, as well as oogonia, were distinguished. Cortical alveoli were hardly detectable within the oocyte, as they were small, sparse and contained few mucopolysaccharides. It is suggested that their role in the fertilization process might be less important than in other teleost species. Fish aged 3 and 4 years were found to be sexually immature, with ovaries containing only previtellogenic oocytes. Vitellogenesis started in December in fish aged 4 + years. Late-developing ovaries showing deposition of yolk protein granules were found at the end of the 5th year of life (May) in specimens measuring 80.0 ± 3.5 cm standard length. This should be regarded as the minimum size at which sexual maturity is reached in S. dumerilii. Final vitellogenesis and oocyte maturation were, however, inhibited in captivity, and extensive follicular atresia took place as the natural spawning season approached. It is suggested that insufficient gonadotrophic stimulation because of confinement stress may be the cause of failed maturation and spawning in this species under culture conditions.