Structural evidence of programmed cell death induction by tungsten in root tip cells of pisum sativum

Previous studies have shown that excess tungsten (W), a rare heavy metal, is toxic to plant cells and may induce a kind of programmed cell death (PCD). In the present study we used transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM) to investigate the subcellular malformations caused byW, supplied as 200 mg/L sodium tungstate (Na 2 WO 4 ) for 12 or 24 h, in root tip cells of Pisum sativum (pea), The objective was to provide additional evidence in support of the notion of PCD induction and the presumed involvement of reactive oxygen species (ROS). It is shown ultrastructurally that W inhibited seedling growth, deranged root tip morphology, induced the collapse and deformation of vacuoles, degraded Golgi bodies, increased the incidence of multivesicular and multilamellar bodies, and caused the detachment of the plasma membrane from the cell walls. Plastids and mitochondria were also affected. By TEM, the endoplasmic reticulum appeared in aggregations of straight, curved or concentric cisternae, frequently enclosing cytoplasmic organelles, while by CLSM it appeared in bright ring-like aggregations and was severely disrupted in mitotic cells. However, no evidence of ROS increase was obtained. Overall, these findings support the view of a W-induced vacuolar destructive PCD without ROS enhancement. © 2019 by the authors. Licensee MDPI, Basel, Switzerland

Προστασία από επαγγελματικούς κινδύνους κατά τις συγκολλήσεις MIG/MAG

184 σ.Η διπλωματική εργασία αυτή πραγματεύεται τις μεθόδους και τα μέσα προστασίας από τους επαγγελματικούς κινδύνους που προκύπτουν κατά την ηλεκτροσυγκόλληση με τηκόμενο ηλεκτρόδιο και προστατευτικό αέριο. Παρουσιάστηκαν τρόποι προστασίας από κινδύνους για την ασφάλεια, από κινδύνους για την υγεία και από εγκάρσιους κινδύνους για την υγεία και την ασφάλεια που προκύπτουν κατά την ηλεκτροσυγκόλληση αυτή καθ' αυτή καθώς και αυτοί που είναι άμεσα συνδεδεμένοι με το εργασιακό περιβάλλον του ηλεκτροσυγκολλητήThis thesis discusses the methods and means of protection against ocupational hazards that appear during the MIG/MAG welding procedure. Means of protection against safety hazards, against health hazards and against transverse health and safety hazards were presented, that appear during welding itself as well as those that are directly connected with the welder's occupational environment.Ελευθέριος Ι. Αδαμάκη

Ephrins and pain

Introduction: The ephrin receptor family is the largest family of receptor tyrosine kinases, which comprises 14 members that are divided into A and B subclasses. The ephrin receptor (Eph-receptor) ligands are named ephrins. Ephrins/Eph receptors interact with a variety of membrane receptors that respond to chemokines, neurotransmitters or growth factors. A growing body of evidence indicates that ephrins/Eph receptors are involved in the modulation of different types of pain. Areas covered: A literature review summarizing the most recent data in terms of ephrins and their ligands and their association with different types of pain. Moreover, the latest knowledge regarding the involvement of ephrins/Eph receptors in pain modulation as well as its possible therapeutic perspectives are presented. Expert opinion: The ephrins/Eph receptors system seems to be an emerging target for pain drug discovery, because it is involved in the pathophysiology of many types of pain. The modulation of different types of pain by selective agonists or antagonists may hold tremendous therapeutic potential in various pain conditions mentioned in this review. However, the current limited but promising data, merit consideration and further investigation. © Informa UK, Ltd

Contemporary diagnosis of bladder cancer

Background: Early diagnosis of bladder cancer is mandatory, as a delay in treatment has been shown to affect prognosis. The current diagnostic standard of cystoscopy and cytology is costly, invasive and inconvenient, whereas advances in molecular biology have resulted in the evolvement of several markers. Objective: To review diagnostic considerations in the use of old and new technical modalities and tests for the detection of bladder cancer. Methods: A PubMed search of the literature concerning bladder cancer diagnosis was performed. Reviews are included on certain topics to avoid extensive reference to separate studies. Conclusion: Recent technical advances have an impact on the management of patients with suspected bladder cancer. Cytology is still an important adjunct in the diagnostic work-up, whereas urine-bound tests may have a role in screening and surveillance. However, cystoscopy is the standard of care for the detection of bladder cancer. Fluorescence cystoscopy is an adjunctive tool, especially for the prompt identification of carcinoma in situ. © 2008 Informa UK Ltd

Tubulin acetylation mediates bisphenol a effects on the microtubule arrays of allium cepa and triticum turgidum

The effects of bisphenol A (BPA), a prevalent endocrine disruptor, on both interphase and mitotic microtubule array organization was examined by immunofluorescence microscopy in meristematic root cells of Triticum turgidum (durum wheat) and Allium cepa (onion). In interphase cells of A. cepa, BPA treatment resulted in substitution of cortical microtubules by annular/spiral tubulin structures, while in T. turgidum BPA induced cortical microtubule fragmentation. Immunolocalization of acetylated α-tubulin revealed that cortical microtubules of T. turgidum were highly acetylated, unlike those of A. cepa. In addition, elevation of tubulin acetylation by trichostatin A in A. cepa resulted in microtubule disruption similar to that observed in T. turgidum. BPA also disrupted all mitotic microtubule arrays in both species. It is also worth noting that mitotic microtubule arrays were acetylated in both plants. As assessed by BPA removal, its effects are reversible. Furthermore, taxol-stabilized microtubules were resistant to BPA, while recovery from oryzalin treatment in BPA solution resulted in the formation of ring-like tubulin conformations. Overall, these findings indicate the following: (1) BPA affects plant mitosis/cytokinesis by disrupting microtubule organization. (2) Microtubule disassembly probably results from impairment of free tubulin subunit polymerization. (3) The differences in cortical microtubule responses to BPA among the species studied are correlated to the degree of tubulin acetylation. © 2019 by the authors. Licensee MDPI, Basel, Switzerland

Cell wall modifications in giant cells induced by the plant parasitic nematode meloidogyne incognita in wild-type (Col-0) and the fra2 arabidopsis thaliana katanin mutant

Meloidogyne incognita is a root knot nematode (RKN) species which is among the most notoriously unmanageable crop pests with a wide host range. It inhabits plants and induces unique feeding site structures within host roots, known as giant cells (GCs). The cell walls of the GCs undergo the process of both thickening and loosening to allow expansion and finally support nutrient uptake by the nematode. In this study, a comparative in situ analysis of cell wall polysaccharides in the GCs of wild-type Col-0 and the microtubule-defective fra2 katanin mutant, both infected with M. incognita has been carried out. The fra2 mutant had an increased infection rate. Moreover, fra2 roots exhibited a differential pectin and hemicellulose distribution when compared to Col-0 probably mirroring the fra2 root developmental defects. Features of fra2 GC walls include the presence of high-esterified pectic homogalacturonan and pectic arabinan, possibly to compensate for the reduced levels of callose, which was omnipresent in GCs of Col-0. Katanin severing of microtubules seems important in plant defense against M. incognita, with the nematode, however, to be nonchalant about this “katanin deficiency” and eventually induce the necessary GC cell wall modifications to establish a feeding site. © 2019 by the authors. Licensee MDPI, Basel, Switzerland

Cortical microtubule orientation in Arabidopsis thaliana root meristematic zone depends on cell division and requires severing by katanin

Background: Transverse cortical microtubule orientation, critical for anisotropic cell expansion, is established in the meristematic root zone. Intending to elucidate the possible prerequisites for this establishment and factors that are involved, microtubule organization was studied in roots of Arabidopsis thaliana, wild‑type and the p60‑katanin mutants fra2, ktn1‑2 and lue1. Transverse cortical microtubule orientation in the meristematic root zone has proven to persist under several regimes inhibiting root elongation. This persistence was attributed to the constant moderate elongation of meristematic cells, prior to mitotic division. Therefore, A. thaliana wild‑type seedlings were treated with aphidicolin, in order to prevent mitosis and inhibit premitotic cell elongation. Results: In roots treated with aphidicolin for 12 h, cell divisions still occurred and microtubules were transverse. After 24 and 48 h of treatment, meristematic cell divisions and the prerequisite elongation ceased, while microtubule orien‑ tation became random. In meristematic cells of the p60‑katanin mutants, apart from a general transverse microtubule pattern, cortical microtubules with random orientation were observed, also converging at several cortical sites, in contrast to the uniform transverse pattern of wild‑type cells. Conclusion: Taken together, these observations reveal that transverse cortical microtubule orientation in the meris‑ tematic zone of A. thaliana root is cell division‑dependent and requires severing by katanin. © The Author(s) 2018. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

Environmentally relevant bisphenol A concentrations effects on the seagrass Cymodocea nodosa different parts elongation: perceptive assessors of toxicity

Toxicity data on bisphenol A (BPA) effects on aquatic macrophytes remain scarce. Therefore, environmentally relevant BPA concentrations (0.03, 0.1, 0.3, 0.5, 1, and 3 μg L−1) were tested on the seagrass Cymodocea nodosa different parts length increase. All plant parts, at low BPA concentrations (0.03–0.3 μg L−1), elongated equally to the control, while their lengthening and elongation rates gradually decreased by increasing BPA concentrations. A gradual increase of “Toxicity index” with increasing BPA concentrations was observed but was lower for juvenile blades and higher for plagiotropic rhizomes and adult leaves. In all parts, the LOECs were 0.3 and the NOECs 0.1 μg L−1 at 10th day. Juvenile blades displayed, under acute stress, lengthening inhibition at lower concentrations than the rhizomes and adult blades, but at a lower extent. The EC50 values were lower for the rhizome internodes, followed by the adult blades and higher for the juvenile blades. Using as a biological “endpoint” the elongation, all C. nodosa parts and specifically the rhizomes and adult blades, followed by intermediate blades, adult sheaths, and juvenile blades, seemed to be sensitive BPA toxicity assessors. The evaluation of the relative sensitivity of the different parts to BPA toxicity could help identify the most suitable seagrass part for early diagnosis of the risk posed by BPA to seagrass meadows and could constitute a valuable tool to derive the seawater quality criteria and to be used in BPA monitoring programs for rational management of the coastal environment. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature

Evaluation of the spatiotemporal effects of bisphenol A on the leaves of the seagrass Cymodocea nodosa

The organic pollutant bisphenol A (BPA) causes adverse effects on aquatic biota. The present study explored the toxicity mechanism of environmentally occurring BPA concentrations (0.03–3 μg L−1) on the seagrass Cymodocea nodosa intermediate leaf photosynthetic machinery. A “mosaic” type BPA effect pattern was observed, with “unaffected” and “affected”” leaf areas. In negatively affected leaf areas cells had a dark appearance and lost their chlorophyll auto-fluorescence, while hydrogen peroxide (H2O2) content increased time-dependently. In the “unaffected” leaf areas, cells exhibited increased phenolic compound production. At 1 μg L−1 of BPA exposure, there was no effect on the fraction of open reaction centers (qP) compared to control and also no significant effect on the quantum yield of non-regulated non-photochemical energy loss in PSII (ΦΝΟ). However, a 3 μg L−1 BPA application resulted in a significant ΦΝΟ increase, even from the first exposure day. Ultrastructural observations revealed electronically dense damaged thylakoids in the plastids, while effects on Golgi dictyosomes and the endoplasmic reticulum were also observed at 3 μg L−1 BPA. The up-regulated H2O2 BPA-derived production seems to be a key factor causing both oxidative damages but probably also triggering retrograde signalling, conferring tolerance to BPA in the “unaffected” leaf areas. © 2020 Elsevier B.V