scholarly journals Light and electron microscopic observations in connection with the developing pistil and seed-appendix (caruncle) of Ricinus communis L.

2014 ◽  
Vol 50 (1-2) ◽  
pp. 345-348 ◽  
Author(s):  
Katherine Liszt ◽  
S. Sárkány ◽  
F. Kadej ◽  
Ann Kovács

The development of the particularly organized stigma and obturator, their fine structure, their function as well as the histological differentiation and the role of the seed-appendix i.e. the caruncle of <em>Ricinus communis</em> L. have been investigated in several developmental phases from the so called "gynoecial primordium" state to the ripe state, 'using the terminology introduced by S a t t 1 e r (1974). The stigma cells are characterized by dens cytoplasm, numerous vesicles mostly of ER origin, ribosomes and negatively stained mitochondria. Dilatation of ER, the appearance of electron opaque substances in it and between the plasmamembran and cell wall are frequent. The degenerating process of some stigma cells will start before the pollination because of autolysis. In the cells of the obturator and young caruncle however dictyosomes can be found more frequently than in stigma cells and the starch content of the ;plastids is remarkable. The thickening of the cell wall is connected with the function of these tissues.

1971 ◽  
Vol 9 (3) ◽  
pp. 581-601
Author(s):  
D. G. ROBINSON ◽  
R. D. PRESTON

Naked swarmers of both Cladophora rupestris and Chaetomorpha melagonium have been examined by the freeze-etching technique. The swarmers of Cladophora, collected just after settling, reveal several layers of granules external to the plasmalemma and internal to the so-called ‘fibrous-layer’. Chaetomorpha swarmers collected just before settling show extrusion of vesicles through the plasmalemma. The structures associated with the membranes are discussed in relation to known features of these swarmers already observed by sectioning. The role of granules in the synthesis of cell wall microfibrils is strengthened though the spatial arrangement of the granules seen in this investigation does not completely fulfil the ‘ordered granule’ hypothesis. Description of, and comments on, features related to cell wall synthesis, particularly the Golgi and vacuolar systems, are given.


2015 ◽  
Vol 74 ◽  
pp. 55-62 ◽  
Author(s):  
Amritpal S. Singh ◽  
Swati Kumari ◽  
Arpan R. Modi ◽  
Bhavesh B. Gajera ◽  
Subhash Narayanan ◽  
...  

2021 ◽  
Vol 7 (7) ◽  
pp. 575
Author(s):  
Cindy Staerck ◽  
Hajar Yaakoub ◽  
Patrick Vandeputte ◽  
Julie Tabiasco ◽  
Charlotte Godon ◽  
...  

Scedosporium species are common fungal pathogens in patients with cystic fibrosis (CF). To colonize the CF lungs, fungi must cope with the host immune response, especially the reactive oxygen species (ROS) released by phagocytic cells. To this aim, pathogens have developed various antioxidant systems, including superoxide dismutases (SODs) which constitute the first-line protection against oxidative stress. Interestingly, one of the S. apiospermum SOD-encoding genes (SODD gene) exhibits a glycosylphosphatidylinositol (GPI) anchor-binding site and encodes a conidial-specific surface SOD. In this study, a SODDΔ mutant was engineered from a non-homologous end joining-deficient strain (KU70Δ) of S. apiospermum. Compared to its parent strain, the double mutant KU70Δ/SODDΔ exhibited increased susceptibility to various oxidizing agents and triazole antifungals. In addition, the loss of SodD resulted in an increased intracellular killing of the conidia by M1 macrophages derived from human blood monocytes, suggesting the involvement of this superoxide dismutase in the evasion to the host defenses. Nevertheless, one cannot disregard an indirect role of the enzyme in the synthesis or assembly of the cell wall components since transmission electron microscopic analysis revealed a thickening of the inner cell wall layer of the conidia. Further studies are needed to confirm the role of this enzyme in the pathogenesis of Scedosporium infections, including the production of a recombinant protein and study of its protective effect against the infection in a mouse model of scedosporiosis.


Chemosphere ◽  
2020 ◽  
Vol 247 ◽  
pp. 125965 ◽  
Author(s):  
Xiupei Zhou ◽  
Sheliang Wang ◽  
Yonghong Liu ◽  
Guoyong Huang ◽  
Shiyuan Yao ◽  
...  

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