1,720,976 research outputs found
Growth and nutrient absorption of two submerged aquatic macrophytes in mesocosms, for reinsertion in a eutrophicated shallow lake
No full textPOSSIBILE ASSORBIMENTO RADICALE DI AGENTI VIRALI DA ACQUE IRRIGUE CONTAMINATE
No full textPS13.51 - 383
POSSIBILE ASSORBIMENTO RADICALE DI AGENTI
VIRALI DA ACQUE IRRIGUE CONTAMINATE
Verani M.*[1], Ciurli A.[2], Carducci A.[1]
[1]Laboratorio di Igiene e Virologia Ambientale – Dipartimento
di Biologia – Università di Pisa ~ Pisa
[2]Dipartimento di Biologia delle Piante Agrarie – Università
di Pisa ~ Pisa
OBIETTIVI: I vegetali a foglia larga come l’insalata,
sono particolarmente a rischio quando la loro irrigazione
viene effettuata con acqua contaminata
come i liquami parzialmente depurati nei quali e di
solito abbondante la presenza di agenti biologici di
origine fecale, tra cui i virus. E’ ben nota la possibilita
di una contaminazione superficiale dei vegetali
attraverso l'irrigazione a spruzzo, ma recentemente
e stato ipotizzato, e talora evidenziato sperimentalmente,
l’assorbimento di tali agenti attraverso le
radici e quindi il loro passaggio alle foglie quando
acque contaminate vengano utilizzate per la subirrigazione
o per colture idroponiche. In tal caso il lavaggio
superficiale sarebbe insufficiente a rimuovere
la contaminazione. Allo scopo di dimostrare tale
adsorbimento e di stimare il livello di contaminazione
delle acque da considerare a rischio e stato
intrapreso uno studio sperimentale in colture idroponiche
di insalata (Lactuca sativa) addizionate di
virus Coxsackies B2.
METODI: Le piantine d’insalata sono state coltivate
in apposite vasche contenenti soluzione nutritiva
contaminata con Coxsakievirus B2 a 3 diluizioni note.
Per valutare l’eventuale penetrazione del virus
attraverso le radici sono state analizzate, per 4
giorni consecutivi, sia le foglie sia l’acqua delle vasche,
mediante una prima fase di eluizioneconcentrazione
con tecniche gia precedentemente
testate e successiva rilevazione virale con metodologie
colturali e molecolari.
RISULTATI: Le prove hanno evidenziato la presenza
di virus (anche su colture cellulari e quindi infettivo)
nelle foglie gia dal primo giorno dopo la contaminazione
con una concentrazione crescente per tutta la
durata dell’esperimento. Contemporaneamente e
stata riscontrato un decadimento piuttosto rapido
del titolo virale nelle acque con entrambi i metodi
di analisi.
CONCLUSIONI: Tali risultati indicano che quando le
radici sono a contatto con acque contaminate a
concentrazione virale superiore a 10^3 GC/ml e
possibile avere penetrazione a livello delle foglie.
Poiche tale valore puo ritrovarsi frequentemente
nei reflui anche parzialmente depurati, e importante
che la qualita virologica delle acque di riuso agricolo
venga valutata prima dell’utilizzo
Arsenic Uptake and Translocation by Plants in Pot and Field Experiments
No full textA work undertaken by pot and field experiments to assess the suitability of poplars and ferns for the in-situ, phytoextraction, of a dumping site with residues from the roasting process of arseno-pyrite is reported. The main characteristic of this site is the high content of both the As metalloid and heavy metals (e.g., Al, Fe, Cu, Co, Cr, Pb). Two poplar clones (Populus deltoides ‘Dvina’ and Populus x canadensis ‘Orion’) and Pteris vittata (Chinese brake fern) were planted in the contaminated soil both ex situ in pots and in situ. Plant survival, As accumulation in plant tissues, leaf content of pigments, soluble proteins, activity of catalase and SH-groups in both roots and leaves were evaluated during a 24-month study period. Both poplar and fern plants exhibited an increase in the activity of catalase and SH group contents when grown in the presence of pyrite ashes. The results showed that the co-planting system (arsenic-hyperaccumulator fern Pteris vittata and Populus clones) was suitable for phytoextraction of multi-contaminated dumping sites. Agronomic measures such as irrigation, soil tillage and amendments also seem to be necessary for the successful establishment of poplar trees and ferns in contaminated soils in order to enhance plant growth through the improvement of soil conditions
Hydraulic and chemical mechanisms in the response of pinus pinaster A i t. To conditions of water stress
No full textThe increase of temperatures at a global scale constitutes a threaten, among the others, for forest ecosystems, and imposes a deeper comprehension of plant behaviour towards drought stress, in order to better plan a sustainable management of water resources. Young plants of Pinus pinaster A i t. were exposed to prolonged drought stress, during which their xylem ABA concentration, leaf water potential and stomatal conductance were measured at regular intervals on the top branches; the same measurements were taken on a sample of control, non stressed plants. At the same time, plant transpiration rate was measured in response to different ABA concentrations and light regimes. Plant responses to variations of environmental parameters were measured, too: leaf T° vs. atmospheric T°; "E" vs. VPD; "A" vs. (CO2). The data suggest that the plant final response to drought stress, i.e. stomatal closure, is mediated by a combination of hydraulic and hormonal regulation; the mechanical one is triggered on the short period and is more quickly reversible, while the chemical one acts on the medium-long term, when the water stress tends to chronicize
Possible Internalization of an Enterovirus in Hydroponically Grown Lettuce
Full text linkSeveral studies have shown that enteric viruses can be transferred onto the surface of vegetables and fruits through spray irrigation, but, recently, reports have suggested viral contamination of vegetables sub-irrigated with reused wastewater. Hydroponic cultures, used to grow ready to eat fresh lettuce, have also been used to study the possibility of viral absorption through roots. This study was conducted to assess a possible risk of viral contamination in lettuce from contaminated water. The leaves of lettuce plants grown in hydroponic cultures where the roots were exposed to water containing Coxsakievirus B2, were analysed for evidence of the virus. The plants and water were sampled at different times and virus was measured using quantitative RT-PCR and infectivity assay. In leaf samples, the lowest observed infective data were lower than the qRT-PCR detection limits, suggesting that free viral RNA or damaged viruses are eliminated rapidly while infectious particles remain stable for a longer time. The obtained data revealed that the leaves were contaminated at a water concentration of 4.11 ± 1 Log Most Probable Number/L (8.03 ± 1 Log GC/L) a concentration observed in contaminated untreated water of wastewater treatment plants. However, the absorption dynamics and whether the virus is inactive in the leaves still remains to be clarified. Nevertheless, this work has practical implications for risk management in using reclaimed water for agricultural use; when irrigated vegetables are destined for raw consumption, virological contamination in water sources should be evaluated
Multidisciplinary integrated characterization of a native Chlorella-like microalgal strain isolated from a municipal landfill leachate
Full text linkTo date, more than one-hundred taxa of green unicellular coccoid organisms have been wrongly included under
the genus Chlorella. This is mainly due to the incomplete characterization resulting from studies that have not
adopted and integrated the description of cell morphology, metabolic characteristics and genomic features. In
this work, a new native Chlorella-like microalgal strain named “SEC_LI_ChL_1”, is described through a multimethod study. This strain was isolated from a pond where municipal landfil leachate flwed before wastewater
treatment. The molecular characterization and the phylogenetic reconstructions based on two different DNA
marker regions (i.e. the concatenated SSU and ITS rRNA gene and the complete 18S rRNA gene) were combined
with light and transmission electron microscope observations, in addition to the analysis of metabolic traits
under four different growing conditions (i.e. autotrophy, heterotrophy, mixotrophy and reduced autotrophy).
The two separate phylogenetic analyses highlighted that the strain falls within the Chlorella-Micractinium clade,
but with two different placements. According to the morphological-ultrastructural and metabolic analyses,
“SEC_LI_ChL_1” shares some features with different Chlorella-like microalgae. Interestingly, two peculiar traits
rarely or never previously described in Chlorella-like microalgal strains were observed: the association of the cells
with endocellular bacteria, and the presence of doublets (i.e. two-celled microalgae aggregates not due to cell
division)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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