Search

Eight Phaseolus vulgaris L. landraces cultivated on farm in marginal areas of Central Italy (Lazio region) were investigated in order to evaluate chemical composition of storage proteins and secondary metabolites fractions. The total protein content showed some differences among landraces; the maximum value was next to 30 g for 100 g of dry weight. The seed storage proteins were screened by polyacrylamide gel electrophoresis (SDS/PAGE): seven landraces exhibited phaseolin patterns type S, one landrace showed a phaseolin pattern type T. A morphological analysis of cotyledon parenchyma performed by scanning electron microscopy (SEM) revealed differences in size of starch granules. Moreover the polyphenolic composition was investigated using HPLC-APCI; from the methanol extracts a flavonoid, kaempferol, and a coumarin, 5,7-dimethoxycoumarin, were identified. To our knowledge, this is the first time that 5,7-dimethoxycoumarin has been reported in P. vulgaris seeds.

Desiccation-tolerant cells must either protect their cellular components from desiccation-induced damage and/or repair it upon rewetting. Subcellular damage to the anhydrobiotic cyanobacterium Chroococcidiopsis sp. CCMEE 029 stored in the desiccated state for 4 years was evaluated at the single-cell level using fluorescent DNA strand breakage labelling, membrane integrity and potential related molecular probes, oxidant-sensing fluorochrome and redox dye. Covalent modifications of dried genomes were assessed by testing their suitability as PCR template. Results suggest that desiccation survivors avoid/and or limit genome fragmentation and genome covalent modifications, preserve intact plasma membranes and phycobiliprotein autofluorescence, exhibit spatially-reduced ROS accumulation and dehydrogenase activity upon rewetting. Damaged cells undergo genome fragmentation, loss of plasma membrane potential and integrity, phycobiliprotein bleaching, whole-cell ROS accumulation and lack respiratory activity upon rewetting. The co-occurrence of live and dead cells within dried aggregates of Chroococcidiopsis confirms that desiccation resistance is not a simple process and that subtle modifications to the cellular milieu are required to dry without dying. It rises also intriguing questions about the triggers of dead cells in response to drying. The capability of desiccation survivors to avoid and/or reduce subcellular damage, shows that protection mechanisms are relevant in the desiccation tolerance of this cyanobacterium.

In plants, MYB transcription factors play important roles in many developmental processes including cell cycle progression, cell differentiation, and lateral organ polarity. It is shown here that the R2R3-MYB AtMYB11 gene is expressed in root and shoot meristems and also in young still meristematic leaf and flower primordia of Arabidopsis. Knock-out atmyb11-I mutants and RNAi plants germinate faster, show a faster hypocotyl and primary root elongation, develop more lateral and adventitious roots, show faster development of the inflorescence, and initiate more lateral inflorescences and fruits than wild-type plants. The opposite phenotype was displayed by plants overexpressing AtMYB11. De novo formation of root meristemoids and, consequently, macroscopic roots, from thin cell layers cultured in vitro was enhanced in explants from atmyb11-I and reduced in those from lines overexpressing AtMYB11. These findings indicate that AtMYB11 modulates overall growth in plants by reducing the proliferation activity of meristematic cells and delaying plant development.

In this work, we determined the tolerance to sodium dodecyl sulphate (SDS) of Azolla filiculoides and of Lemna minor. The presence of the detergent in the media affected growth more than the chlorophyll content. On the basis of the effect indices, Lemna is more tolerant to SDS than Azolla. The fern had a better capacity, compared with duckweed, to remove and accumulate the pollutant.

Sensor technology based on immunological ELISA analyses combined with various electrochemical detection systems is being developed to quantify phycotoxins in algae and seafood. The use of disposable screen-printed electrodes for the immunosensor development is illustrated. Laboratory responses on contaminated mussels were obtained by domoic acid and saxitoxin sensors with detection limit of 5 and 0.1 ng/ml respectively. Application to algal extracts was also performed to detect domoic acid concentration in phytoplankton populations along Latium (Middle Tyrrhenian Sea, Mediterranean Sea) coast.

Several diatoms of the genus Pseudo-nitzschia are able to produce domoic acid (DA), a neurotoxic aminoacid responsible for Amnesic Shellfish Poisoning (ASP) in humans and animals worldwide. Pseudo-nitzschia spp. are widespread along Italian coast, however current knowledge of their diversity, temporal succession and potential toxicity is limited to restricted areas. Blooms of these diatoms have been increasingly recorded along the Latium region coast (Middle Tyrrhenian Sea, Mediterranean Sea) in the last decades prompting investigation of Pseudo-nitzschia diversity and potential toxicity in natural communities from coastal stations over one year. Results of the taxonomical analysis are here reported together with distribution data, at species complex resolution, that were collected during a regional long-term program. Transmission electron microscopy on acid cleaned frustules ascertained the presence and identity of eight Pseudo-nitzschia species, six of which are known ASP producers. One species, P. inflatula, is reported for the first time from Italian waters. Distributional data evidenced coexistence of different species during blooms, seasonal cycles and inter-annual variability, abundances of the genus reached 107 cell/l−1.

Plant capability to lower antimicrobial drug concentration, such as sulfonamide (Sulfadimethoxine) and a quinolone (Flumequine), widely used in intensive farming, has been tested in laboratory models already set up in previous experiments. The aim of this work was to determine phytoremediation capability of different macrophytes, Azolla, Lemna and Pistia, by evaluating the effects on both plant growth and drug uptake/degradation. The three plant models survived even at very high drug concentrations although toxic effects were evident, particularly in the case of Pistia that died after 3 weeks at the highest concentrations. Furthermore, the three plant models are able to absorb and store drugs, particularly Azolla, hypothesise an important role for these plants as a bioremediation technique in the future.

Modern microscopy in life sciences is ruled by development and exploration of new dyes and stains (probes for histochemical staining, quantum dots, fluorescent proteins etc.) on one side, and technological improvements and innovations for fluorescence microscopy-especially high resolution and optical sectioning microscopy-on the other side. Concerning the technical innovations, several ingenious inventions have been made available for confocal microscopy. First, the acousto optical tunable filter, which allows switching and dimming of laser lines. Second the spectral detector, employing mirror sliders in front of the detectors which allow continuous tuning of the spectral emission band detected by the sensor. Third, the most challenging task: a substitute to the classical beam splitter-the device which is restricting fluorescence microscopy most. This was solved by introduction of the acousto optical beam splitter. The very last device which is still lacking flexibility is the laser source, operating only at non-equidistant frequencies and requiring a set of quite different laser sources as gas lasers, solid state lasers or diode lasers. A new approach by supercontinuum light sources is presented and discussed, which significantly enhances flexibility and coverage of the excitation spectra of typical, rare and natural fluorochromes.

The cytomorphology and the exopolysaccharides of two heterocystous cyanobacteria, Scytonema ocellatum CP8-2 and Fischerella maior NAV 10 bis, isolated from biofilms collected in two Roman hypogea, were investigated from a cytochemical, ultrastructural and biochemical point of view. Cytochemical stains and observation using light and transmission electron microscopy showed a bi-layered sheath in both cyanobacteria, with a different composition in sulphated and carboxylic groups. RP-HPLC of the extracted polysaccharides forming the mucous matrix showed the neutral sugars glucose and arabinose and the charged galacturonic acid as the main monosaccharides. Circular dichroism spectra recorded at varying pH and temperature showed that these polymers followed a random coil model and did not present a structured organised conformation at ambient temperature. The outcomes of this study increase the understanding of colonization and biodeterioration of important archaeological and cultural sites by cyanobacterial b...

Dried monolayers of Chroococcidiopsis sp. 029, a desiccation-tolerant, endolithic cyanobacterium, were exposed to a simulated martian-surface UV and visible light flux, which may also approximate to the worst-case scenario for the Archean Earth. After 5 min, there was a 99% loss of cell viability, and there were no survivors after 30 min. However, this survival was approximately 10 times higher than that previously reported for Bacillus subtilis. We show that under 1 mm of rock, Chroococcidiopsis sp. could survive (and potentially grow) under the high martian UV flux if water and nutrient requirements for growth were met. In isolated cells, phycobilisomes and esterases remained intact hours after viability was lost. Esterase activity was reduced by 99% after a 1-h exposure, while 99% loss of autofluorescence required a 4-h exposure. However, cell morphology was not changed, and DNA was still detectable by 4',6-diamidino-2-phenylindole staining after an 8-h exposure (equivalent to approximately 1 day on Mars at the equator). Under 1 mm of simulant martian soil or gneiss, the effect of UV radiation could not be detected on esterase activity or autofluorescence after 4 h. These results show that under the intense martian UV flux the morphological signatures of life can persist even after viability, enzymatic activity, and pigmentation have been destroyed. Finally, the global dispersal of viable, isolated cells of even this desiccation-tolerant, ionizing-radiation-resistant microorganism on Mars is unlikely as they are killed quickly by unattenuated UV radiation when in a desiccated state. These findings have implications for the survival of diverse microbial contaminants dispersed during the course of human exploratory class missions on the surface of Mars.

The diatom assemblages within phototrophic biofilms in secondary treatment tanks of the Fiumicino Airport (Rome, Italy) wastewater treatment plant were investigated. Qualitative and quantitative comparisons were made between assemblages in sedimentation and chlorination tanks, on the tank walls and artificial substrata, on four sampling occasions. The assemblages were characterised by a rather stable species composition, low species diversity and dominance of raphid taxa. Correspondence analysis of diatom relative abundance data with regard to seasonal, site and substratum variation revealed both temporal and spatial differences in species assemblages. Rather than species composition changing over time between different sampling sites and surfaces, the proportional contributions of individual species to the assemblages varied with season. Biovolume data indicated that this outdoor system supported extensive diatom growth (high diatom biomass productivity). The potential use of autochthonous, diatom biofil...

With 2 figures and 1 table in the text Abstract: Leptolyngbya strains VRUC135 andCSC7-l, isolated from biofilms present in Roman hypogea, were employed as experimental strains to optimize molecular tech- niques to approach the taxonomy of different epilithic strains of Leptolyngbya, main- tained in our laboratory. High quality genomic DNAs were obtained according to the CTAB method, while low quality DNAs were obtained with the hot phenol method. High quality DNAs were used in gradient PCRs to optimize annealing temperatures for 16S- 23S rRNA operon amplification and genomic PCR fingerprinting, with primers derived from HIP1, STRR, and LTRR sequences. At the optimized conditions, no significant dif- ferences in PCR products were observed using as template low quality DNAs. The em- ployment of both molecular approaches suggested that Leptolyngbya VRUC 135 and CSC7-1 are different species: the partial sequence of 16S rRNA gene from Leptolyngbya CSC7-1 showed 91.6 % nucleotide identity with the 16S rRNA gene of Leptolyngbya VRUC135, and both strains exhibited a high genetic diversity when typed with HIP1, STRR, and LTRR PCR fingerprinting.

The photosynthetic and light acclimation capability of phototrophic biofilms collected seasonally from the wastewater treatment plant (WWTP) of Fiumicino Airport (Rome, Italy) was tested in culture at different irradiance conditions. Photosynthesis versus Irradiance (P/I) curves were recorded on 15, 30 and 45 day aged communities and chlorophylls, carotenoids and phycobiliproteins quantified. Light microscopy observations were performed to evaluate inoculum species composition and taxonomic shifts over time in cultured biofilms. Phototrophs acclimated to different irradiances by varying the photosynthetic efficiency, maximum photosynthetic rate and pigment content. Community age and biomass variation also affected photosynthesis-light response. Marked shifts towards the prevalence of cyanobacteria were observed in summer and autumn biofilms kept at the highest experimental irradiances. Data indicated high productivity and acclimation potential of cultured phototrophic biofilms in view of their application for bioremediation technologies.

The nitrogen-fixing filamentous cyanobacterium Nostoc PCC 7120 (formerly named Anabaena PCC 7120) possesses two genes for superoxide dismutase, a unique membrane-associated manganese superoxide dismutase (MnSOD) and a soluble iron superoxide dismutase (FeSOD). A phylogenetic analysis of FeSODs shows that cyanobacterial enzymes form a well separated cluster with filamentous species found in one subcluster and unicellular species in the other. Activity staining, inhibition patterns, and immunogold labeling show that FeSOD is localized in the cytosol of vegetative cells and heterocysts (nitrogenase containing specialized cells formed during nitrogen-limiting conditions). The recombinant Nostoc FeSOD is a homodimeric, acidic enzyme exhibiting the characteristic iron peak at 350 nm in its ferric state, an almost 100% occupancy of iron per subunit, a specific activity using the ferricytochrome assay of (2040 +/- 90) units mg(-1) at pH 7.8, and a dissociation constant Kd of the azide-FeSOD complex of 2.1 mM. Using stopped flow spectroscopy it was shown that the decay of superoxide in the presence of various FeSOD concentrations is first-order in enzyme concentration allowing the calculation of the catalytic rate constants, which increase with decreasing pH: 5.3 x 10(9) M(-1) s(-1) (pH 7) to 4.8 x 10(6) M(-1) s(-1) (pH 10). FeSOD and MnSOD complement each other to keep the superoxide level low in Nostoc PCC 7120, which is discussed with respect to the fact that Nostoc PCC 7120 exhibits oxygenic photosynthesis and oxygen-dependent respiration within a single prokaryotic cell and also has the ability to form differentiated cells under nitrogen-limiting conditions.

Saffron (Crocus sativus L. Iridaceae) chromoplasts and other plastids were studied by electron microscope to determine their structure, origin and pigment localization. Plastids from pistils of floral buds and flowers at anthesis, dried and decoloured stigmas, and green and senescent leaves were examined. Results indicated that mature saffron chromoplasts occur in the red parts of stigmas and have a reticulo-tubular structure. They contain a reticulum of tubules and plastoglobules. Tubules formed dilated vesicles mainly while plastoglobules appeared numerous and scattered on the whole chromoplast. Chromoplasts appeared in red stigma of very young floral buds. They originated from amyloplasts, the only plastids occurring in the colourless basal portion of style, as well as in the parenchyma of ovary and corm. Transition forms of plastid as amylo-chromoplast, occur in the yellow parts of stigma and style. Senescent leaves did not show plastids with structure similar to the chromoplast of red stigma. Red pig...

The objectives of the present study were: (1) to localise, at the subcellular level, the allergens in pollen of Cupressaceae species, using a monoclonal antibody (mAb 5E6) that is specific for carbohydrate epitopes of allergenic components of Cupressus arizonica pollen extract; (2) to determine whether the glycidic epitope recognised by mAb 5E6 was present in pollen of allergenic species taxonomically unrelated to Cupressaceae; and (3) to determine whether human IgE purified from monosensitive patients recognises the same epitope as mAb 5E6 in Cupressaceae pollen. Immunogold labelling of mAb 5E6 showed a high density of gold particles on the orbicules, supporting the hypothesis that they are important vectors of allergens. A high density was also found on the exine and in the cytoplasm, with the latter finding confirming that fragments of pollen ruptured under humid conditions can represent a vector. The glycidic epitope recognised by mAb 5E6 was detected in all of the species taxonomically unrelated to Cupressaceae, although with varying density. Human IgE recognised the same epitope as mAb 5E6. These findings are consistent with observations of diffuse allergenic cross-reactivity among various allergens. The in situ localisation of a common epitope recognised by both a monoclonal antibody and human IgE could be of importance in immunotherapy.

Plants can be an interesting tool for in situ remediation of drug contaminated waters. In a laboratory model Azolla filiculoides Lam., an aquatic fern known to absorb pollutants. has been exposed to an environmental persistent antibiotic commonly used in intensive farming. sulphadimethoxine (S), to test its bioremediation capability. In a 5 week experiment. plants were cultivated outdoor at four drug concentrations (50, 150. 300 and 450 mg 1(-1)) in N-free mineral medium. Drug affects growth rate (as biomass yield per week), N-2-fixation, heterocyst frequency, but plants are able to survive. Notwithstanding. at all concentrations tested drug was actively removed from the medium and the accumulation in the biomass is in order of magnitude up to mg g(-1) plant dry weight (1000 ppm). Drug uptake and degradation rates increase with S concentrations in the culture medium. The efficacy of the model was very high, These results demonstrated that Azolla can be taken into consideration as a tool for sulphonamides environmental monitoring and decontamination. (C) 2002 Elsevier Science Ltd. All rights reserved.

UV radiations are principal causes of skin cancer and aging. Suntan creams were developed to protect epidermis and derma layers against photodegradation and photooxidation. The addition of antioxidant plant extracts (i.e. essential oil) to sunscreens is habitually performed, to increase their UV protective effects and to contrast pro-radical and cytotoxic compounds present in these solutions. According to these observations, in the present work, the alteration of chemical composition and bioactive properties of Lavandula angustifolia Miller essential oil, exposed to UV light, was investigated. UV induced a significant deterioration of lavender oil biochemical profile. Moreover, the antioxidant activity of this solution, in in vitro tests and directly on B16-F10 melanoma cells, greatly decreased after UV treatment. Our results also showed that essential oil was shielded from UV stress by propolis addition. Even after UV treatment, bee glue highly protected lavender oil secondary metabolites from degradation and also preserved their antiradical properties, both in in vitro antioxidant assays and in cell oxidative damage evaluations. This research proposed propolis as highly efficient UV protective and antiradical additive for sunscreens, cosmetics and alimentary or pharmaceutical products containing plant extracts.

Some natural structures show three-dimensional morphologies on the micro- and nano- scale, characterized by levels of symmetry and complexity well far beyond those fabricated by best technologies available. This is the case of diatoms, unicellular microalgae, whose protoplasm is enclosed in a nanoporous microshell, made of hydrogenated amorphous silica, called frustule. We have studied the optical properties of Arachnoidiscus sp. single valves both in visible and ultraviolet range. We found photonic effects due to diffraction by ordered pattern of pores and slits, accordingly to an elaborated theoretical model. For the first time, we experimentally revealed spatial separation of focused light in different spots, which could be the basis of a micro-bio-spectrometer. Characterization of such intricate structures can be of great inspiration for photonic devices of next generation. © 2014 Ferrara et al.

Water fern (Azolla filiculoides Lam.) has been assessed for nitrogen and phosphorus removal in outdoor experiments comparing sewage water (S) from an experimental aquaculture plant, well water (W) and mineral growth medium Hoagland (H). The experiments were undertaken during the spring and the summer. The yield of fern biomass and nitrogenase activity was higher in H than in W and S waters. The enzyme activity had a decreasing trend with significant differences (p

Species of Dinophysis Ehrenberg sensu lato were collected opportunistically along the southern Adriatic coasts (Apulia, Italy) during a survey of phytoplankton community structure and dynamics carried out from 1995 to 1997. Most previous reports of Dinophysis spp. in the Adriatic Sea concentrated on northern populations, with few data available on phytoplankton inhabiting the southern coastal areas. Thus, the present study is the first on Dinophysis sensu lato species composition and spatio-temporal distribution in these essentially oligotrophic waters. Twelve Dinophysis species were identified; some of which can be assigned to the genus Phalacroma. Dinophysis sacculus, D. fortii, D. caudata, Phalacroma rotundatum and P. mitra are potentially producers of diarrhetic shellfish poisoning. Seasonal changes in Dinophysis and Phalacroma populations are presented, as well as their relationships with hydrographic and biotic factors. These dinoflagellates were associated with mixing conditions, low water temperatures and high nutrient inputs. Furthermore, the statistical analysis evidenced significant correlations of Dinophysis species to chlorophyll a and phytoplankton. Ecological implications arising from the data are discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.