The role of the lodicule and epiblast in determining natural hybrids of Avena sativa × fatua in cultivated oats

1969 ◽  
Vol 47 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Bernard R. Baum
Keyword(s):  
Experimental Evidence ◽  
Avena Sativa ◽  
Taxonomic Status ◽  
Natural Hybrids ◽  
Breeding History ◽  
Putative Hybrids

Most reports on natural hybrids between A. sativa and A. fatua are not supported by definitive experimental evidence. Those authorities who have proved that natural hybrids do occur were assisted by the fact that both parents were known and occurred with the putative hybrids. The present study was conducted on samples of foundation plots from Canadian origin. Very useful characters were found in the lodicules and in the epiblasts which made it possible to detect F1 hybrids with precision in seeds of cultivated oats irrespective of their external morphologic markers. A hypothesis that the epiblast of the Fatua-type is dominant over the Sativa-type in F1 hybrids is set forth on the basis of the present findings. Higher frequencies of the Fatua-type epiblast were found in the samples where the lowest frequency of the Fatua-type lodicule was observed, because these samples were cultivars which had in their breeding history more crosses with A. byzantina than the others had. The importance of the lodicule and epiblast characters as markers is reassessed, and their reliability was reevaluated in view of the similarity of characters found in the epiblast of A. fatua and A. byzantina, and in view of the present findings. The taxonomic status of A. fatua and A. sativa is also discussed.

TESTING GOAL-DRIVEN CAPTURE BY THREAT

2019 ◽  
Author(s):  
Chris Robert Harrison Brown
Keyword(s):  
Experimental Evidence ◽  
Attentional Capture ◽  
Critical Role ◽  
Experimental Manipulation ◽  
Contingent Capture ◽  
Top Down ◽  
Affective Stimuli ◽  
Clinical Disorders ◽  
Positive Stimuli

Attention has long been characterised within prominent models as reflecting a competition between goal-driven and stimulus-driven processes. It remains unclear, however, how involuntary attentional capture by affective stimuli, such as threat-laden content, fits into such models. While such effects were traditionally held to reflect stimulus-driven processes, recent research has increasingly implicated a critical role of goal-driven processes. Here we test an alternative goal-driven account of involuntary attentional capture by threat, using an experimental manipulation of goal-driven attention. To this end we combined the classic ‘contingent capture’ and ‘emotion-induced blink’ (EIB) paradigms in an RSVP task with both positive or threatening target search goals. Across six experiments, positive and threat distractors were presented in peripheral, parafoveal, and central locations. Across all distractor locations, we found that involuntary attentional capture by irrelevant threatening distractors could be induced via the adoption of a search goal for a threatening category; adopting a goal for a positive category conversely led to capture only by positive stimuli. Our findings provide direct experimental evidence for a causal role of voluntary goals in involuntary capture by irrelevant threat stimuli, and hence demonstrate the plausibility of a top-down account of this phenomenon. We discuss the implications of these findings in relation to current cognitive models of attention and clinical disorders.

scholarly journals Experimental evidence of pathogenic role of IgG autoantibodies in IgA nephropathy

2021 ◽  
Vol 118 ◽  
pp. 102593
Author(s):  
Zina Moldoveanu ◽  
Hitoshi Suzuki ◽  
Colin Reily ◽  
Kenji Satake ◽  
Lea Novak ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Iga Nephropathy ◽  
Pathogenic Role

scholarly journals O-GlcNAcylation protein disruption by Thiamet G promotes changes on the GBM U87-MG cells secretome molecular signature

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Maria Cecilia Oliveira-Nunes ◽  
Glaucia Julião ◽  
Aline Menezes ◽  
Fernanda Mariath ◽  
John A. Hanover ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Critical Role ◽  
Molecular Signature ◽  
Label Free ◽  
Intercellular Signaling ◽  
Tumor Aggressiveness ◽  
Signaling Axis ◽  
Literature Evidence ◽  
Therapeutic Tools

AbstractGlioblastoma (GBM) is a grade IV glioma highly aggressive and refractory to the therapeutic approaches currently in use. O-GlcNAcylation plays a key role for tumor aggressiveness and progression in different types of cancer; however, experimental evidence of its involvement in GBM are still lacking. Here, we show that O-GlcNAcylation plays a critical role in maintaining the composition of the GBM secretome, whereas inhibition of OGA activity disrupts the intercellular signaling via microvesicles. Using a label-free quantitative proteomics methodology, we identified 51 proteins in the GBM secretome whose abundance was significantly altered by activity inhibition of O-GlcNAcase (iOGA). Among these proteins, we observed that proteins related to proteasome activity and to regulation of immune response in the tumor microenvironment were consistently downregulated in GBM cells upon iOGA. While the proteins IGFBP3, IL-6 and HSPA5 were downregulated in GBM iOGA cells, the protein SQSTM1/p62 was exclusively found in GBM cells under iOGA. These findings were in line with literature evidence on the role of p62/IL-6 signaling axis in suppressing tumor aggressiveness and our experimental evidence showing a decrease in radioresistance potential of these cells. Taken together, our findings provide evidence that OGA activity may regulate the p62 and IL-6 abundance in the GBM secretome. We propose that the assessment of tumor status from the main proteins present in its secretome may contribute to the advancement of diagnostic, prognostic and even therapeutic tools to approach this relevant malignancy.

Cytoplasmic streaming in characean cells: role of subcortical fibrils

1980 ◽  
Vol 58 (7) ◽  
pp. 760-765 ◽  
Author(s):  
Eiji Kamitsubo
Keyword(s):  
Electrical Stimulation ◽  
Experimental Evidence ◽  
Cytoplasmic Streaming ◽  
Motive Force ◽  
Microbeam Irradiation ◽  
Subcortical Fibrils

Three or four parallel fibrils of ca. 0.1 μm in width attached to each file of chloroplasts in intact internodal cells generate the motive force for cytoplasmic streaming. Experimental evidence for this conclusion is drawn from experiments in which fibrillar motion and streaming are interrupted by centrifugation, microbeam irradiation, and electrical stimulation. The role of Pb2+ in preventing cessation of cytoplasmic streaming after electrical stimulation is interpreted in terms of localized changes in viscosity of the cytoplasm.

CYTOGENETICS OF SOME SPECIES AND NATURAL HYBRIDS IN PROSOPIS (LEGUMINOSAE)

1975 ◽  
Vol 17 (2) ◽  
pp. 253-262 ◽  
Author(s):  
J. H. Hunziker ◽  
L. Poggio ◽  
C. A. Naranjo ◽  
R. A. Palacios ◽  
A. B. Andrada
Keyword(s):  
Chromosome Number ◽  
Interspecific Hybrids ◽  
Vegetative Reproduction ◽  
General Lack ◽  
Cytological Data ◽  
Natural Hybrids ◽  
Regular Meiosis ◽  
Putative Hybrids

Cytological results on 12 species and 4 putative hybrids of Prosopis are presented. Of these, 5 species and 4 hybrids have been hitherto unknown cytologically. The following species proved to be diploid (2n = 28) and constitute new chromosome number determinations for the genus: P. algarobilla Griseb., P. hassleri Harms, P. nigra (Griseb.) Hieron., P. patagonica Speg., P. tamarugo Phil. The diploid nature of some races of P. juliflora (Sw.) DC. is established; apparently under this taxon there are also tetraploid populations. The following putative interspecific hybrids showed regular meiosis with formation of 14 bivalents: P. vinalillo Stuck. (P. ruscifolia × P. alba?), P. alba × P. nigra? and P. hassleri × P. ruscifolia?.So far 28 taxa of the genus have been studied cytologically; 27 of these are diploid. The scarcity of polyploidy in the genus (3.5%) might be a consequence of the almost general lack of means of vegetative reproduction and of the absence of chromosome repatterning in primary speciation. Results of other authors concerning cytological data are also discussed.

Sign in / Sign up

Export Citation Format

Share Document