Advanced techniques to investigate the internalization mechanism of TiO2 NPs in the roots grown in a biosolid-amended agricultural soil

Plants play an important role in introducing the engineered nanoparticles (ENPs) into the food chain. The pathway of ENPs uptake from soil, their distribution in the edible plant parts, and their impact in the food production are important issues to be investigated. In the present study, Pisum sativum plants were grown at microcosm scale under medium-term TiO2 NPs exposure, to possibly mime environmental conditions in an agricultural soil amended with biosolids from a wastewater treatment plant in Pisa, Italy. TiO2 NPs were applied as pure rutile, pure anatase and a mixture of both crystalline phases in the biosolid amended-soil. Micro-XRF and μ-XANES from ID21 beamline were used for Ti elemental mapping and crystalline phase identification to indicate a relative distribution/localization of TiO2 crystalline phases within a given cross-section of roots, as well as the possible speciation and preferential crystalline phase uptake in the roots. Titanium in roots showed a main localization in the rizoderma, independently of the crystalline phase. Fewer Ti spots were found localized in the cortex or in vessel, however the roots grown in presence of a mixture of both phases showed a main presence of anatase, suggesting a preferential adsorption and translocation of this crystalline form through the roots. Our data indicated also a reduced translocation of Ti to the aerial part of the plant, confirming the chemical analysis of shoots and roots separately, which showed that Ti concentration was about 40 times lower in the upper part than in the below ground tissues. The TiO2 NPs were characterized on the basis of their size and shape by TEM analysis. Moreover, observations on cell ultrastructure of control and of anatase, rutile and mixture of both crystalline phases treated roots were performed. The root cells of plant grown in the presence of all NPs treatments shared the same alterations of ultrastructure: mitochondria with swollen cristae, nuclei with condensed chromatin, and part of the cytoplasm degraded, probably in consequence of an autophagic process. As detected by μ-XRF and μ-XANES, electron dense prismatic or round profiled particles of about 30-40 nm were observed mainly in form of aggregates in the intercellular spaces or crossing the wall of the cells next to rizoderma and in the cortex cells. Furthermore, the anatase treated cells were mostly damaged in respect to control and rutile treated roots, and more frequently internalized NPs were observed in these samples

Language production impairments in patients with a first episode of psychosis

Language production has often been described as impaired in psychiatric diseases such as in psychosis. Nevertheless, little is known about the characteristics of linguistic difficulties and their relation with other cognitive domains in patients with a first episode of psychosis (FEP), either affective or non-affective. To deepen our comprehension of linguistic profile in FEP, 133 patients with FEP (95 non-affective, FEP-NA; 38 affective, FEP-A) and 133 healthy controls (HC) were assessed with a narrative discourse task. Speech samples were systematically analyzed with a well-established multilevel procedure investigating both micro- (lexicon, morphology, syntax) and macro-linguistic (discourse coherence, pragmatics) levels of linguistic processing. Executive functioning and IQ were also evaluated. Both linguistic and neuropsychological measures were secondarily implemented with a machine learning approach in order to explore their predictive accuracy in classifying participants as FEP or HC. Compared to HC, FEP patients showed language production difficulty at both micro- and macro-linguistic levels. As for the former, FEP produced shorter and simpler sentences and fewer words per minute, along with a reduced number of lexical fillers, compared to HC. At the macro-linguistic level, FEP performance was impaired in local coherence, which was paired with a higher percentage of utterances with semantic errors. Linguistic measures were not correlated with any neuropsychological variables. No significant differences emerged between FEP-NA and FEP-A (p≥0.02, after Bonferroni correction). Machine learning analysis showed an accuracy of group prediction of 76.36% using language features only, with semantic variables being the most impactful. Such a percentage was enhanced when paired with clinical and neuropsychological variables. Results confirm the presence of language production deficits already at the first episode of the illness, being such impairment not related to other cognitive domains. The high accuracy obtained by the linguistic set of features in classifying groups support the use of machine learning methods in neuroscience investigations

Harmomegathy in heteranteric species

Harmomegathy was described in five heterantheric species. The harmomegatic mechanism was evidentiated "in vitro" using solutions at different sucrose concentration

IDENTIFICATION OF SHOOT APICAL MERISTEM CELLS COMMITTED TO FORM VASCULAR ELEMENTS IN PISUM SATIVUM AND VICIA FABA

A cytochemical study of naphthol AS-D esterases in vegetative shoot apices of Pisum sativum and Vicia faba L. has shown the presence of carboxyl esterases (E.C. 3.1.1.1.) in those meristem cells already committed to form vascular elements. These cells form a sequence linking the morphologically identifiable procambium to the cells of the tunica layers at a site either already identifiable as the next primordium or which will form the next primordium. The implications of this result are briefly discussed in relation to the control of primordia formation and procambial cell development

Ultrastructure, viability, and in vitro germination of the tricellular Sambucus nigra L. pollen

Mature pollen grains of Sambucus nigra L. are tricolporate, isopolar, 12.5 mm wide, 25 mm long, and tricellular. They have a tectate exine, a bilayered nexine, and a thin intine. The vegetative cell has abundant rough endoplasmic reticulum, many well-structured mitochondria, numerous apparently inactive dictyosomes, immature dividing, and starch-filled plastids and lipid bodies. The sperm cells have few and poorly structured organelles. They are linked by cytoplasmic bridges, indicating a persistent physiological unit, and are surrounded by fibrillar polysaccharide material. Freshly released pollen is 95% viable. Three- and 4-year-old pollen grains stored at 20C are 78.2% and 43% viable, respectively. In vitro germination requirements and pollen tube growth are more similar to those of bicellular pollen than to those of tricellular pollen

Stress integrated tests and cytological analyses reveal Brassica villosa subsp. drepanensis seed quality decrease upon long-term storage

Under stress integrated germination test (SIGT), seeds undergo osmo-saline stresses, which enable to detect differences in vigour of long-term stored seeds with high germination percentage (G%). The quality of Brassica villosa subsp. drepanensis seeds stored in a genebank (at -20°C for 16 years) was compared with seeds at harvest by standard germination tests (GT), SIGT and cytogenetic analysis. No differences were detected in G% and mean germination time under GT. Conversely, SIGT performed with NaCl -0.9MPa osmotic potential did not influence G% at harvest but reduced that of stored seeds, SIGT at -1.4MPa reduced G% of both. Cytogenetic analysis showed reduction of mitotic index, appearance of chromosomal aberrations and smaller nucleoli in stored seeds compared with harvest seeds germinated in water. SIGT at -0.9MPa had no effect on mitotic index, but increased chromosome aberrations and nucleoli number. SIGTat -1.4MPa inhibited G%of harvest and stored seeds, reduced mitoses in harvest and completely prevented it in stored seeds. The results indicate that GT does not faithfully reflect the quality of stored seeds, with misinterpretation of their vigour, whereas SIGT and cytogenetical parameters are sensitive, reliable and inexpensive methods for early prediction of genetic erosion in germplasm banks