The ultrastructure of sexual reproduction in Pythium acanthicum

1976 ◽  
Vol 54 (19) ◽  
pp. 2193-2203 ◽  
Author(s):  
R. H. Haskins ◽  
J. A. Brushaber ◽  
J. J. Child ◽  
L. B. Holtby
Keyword(s):  
Endoplasmic Reticulum ◽  
Sexual Reproduction ◽  
Contact Zone ◽  
Periplasmic Space ◽  
Spine Development ◽  
Storage Body ◽  
Cytoplasmic Ribosomes ◽  
Pythium Acanthicum ◽  
Hyphal Tip

The young oogonium and young antheridium in Pythium acanthicum Drechsler are densely and randomly packed with numerous mitochondria, dictyosomes, nuclei, interlocking vacuoles of several types, some of which contain a dense storage body, a variety of vesicles, endoplasmic reticulum, and cytoplasmic ribosomes. Wall vesicles, evenly distributed next to the plasma-lemma in rapidly growing oogonia, become localized in groups at points where they appear to initiate the hyphal tip-like development of the oogonial spines. They are also found on both sides of the antheridium−oogonium contact zone. Spine development starts shortly after antheridium−oogonial contact is made and ceases with entry of antheridial material into the oogonium. Excess nuclei, mitochondria, and various organelles are abandoned in the periplasmic space, where they normally quickly disintegrate when the oospore is formed. The periplasmic space is invaded frequently by vegetative hyphae originating outside of the oogonium.

Secondary origin, hybridization and sexual reproduction in a diploid–tetraploid contact zone of the facultatively apomictic orchid Zygopetalum mackayi

Plant Biology ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 939-948
Author(s):  
Y. A. Moura ◽  
A. Alves‐Pereira ◽  
C. C. da Silva ◽  
L. M. Souza ◽  
A. P. de Souza ◽  
...  
Keyword(s):  
Sexual Reproduction ◽  
Contact Zone ◽  
Secondary Origin

scholarly journals Structure and Distribution of Organelles and Cellular Location of Calcium Transporters in Neurospora crassa

2009 ◽  
Vol 8 (12) ◽  
pp. 1845-1855 ◽  
Author(s):  
Barry J. Bowman ◽  
Marija Draskovic ◽  
Michael Freitag ◽  
Emma Jean Bowman
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Neurospora Crassa ◽  
Fluorescent Protein ◽  
Protein A ◽  
Vacuolar Membrane ◽  
Red Fluorescent Protein ◽  
Animal Cells ◽  
Marker Proteins ◽  
Hyphal Tip

ABSTRACT We wanted to examine the cellular locations of four Neurospora crassa proteins that transport calcium. However, the structure and distribution of organelles in live hyphae of N. crassa have not been comprehensively described. Therefore, we made recombinant genes that generate translational fusions of putative organellar marker proteins with green or red fluorescent protein. We observed putative endoplasmic reticulum proteins, encoded by grp-78 and dpm, in the nuclear envelope and associated membranes. Proteins of the vacuolar membrane, encoded by vam-3 and vma-1, were in an interconnected network of small tubules and vesicles near the hyphal tip, while in more distal regions they were in large and small spherical vacuoles. Mitochondria, visualized with tagged ARG-4, were abundant in all regions of the hyphae. Similarly, we tagged the four N. crassa proteins that transport calcium with green or red fluorescent protein to examine their cellular locations. NCA-1 protein, a homolog of the SERCA-type Ca2+-ATPase of animal cells, colocalized with the endoplasmic reticulum markers. The NCA-2 and NCA-3 proteins are homologs of Ca2+-ATPases in the vacuolar membrane in yeast or in the plasma membrane in animal cells. They colocalized with markers in the vacuolar membrane, and they also occurred in the plasma membrane in regions of the hyphae more than 1 mm from the tip. The cax gene encodes a Ca2+/H+ exchange protein found in vacuoles. As expected, the CAX protein localized to the vacuolar compartment. We observed, approximately 50 to 100 μm from the tip, a few spherical organelles that had high amounts of tagged CAX protein and tagged subunits of the vacuolar ATPase (VMA-1 and VMA-5). We suggest that this organelle, not described previously in N. crassa, may have a role in sequestering calcium.

scholarly journals THE STRUCTURE AND FORMATION OF PROTEIN GRANULES IN THE FAT BODY OF AN INSECT

1965 ◽  
Vol 26 (3) ◽  
pp. 857-884 ◽  
Author(s):  
M. Locke ◽  
J. V. Collins
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Fat Body ◽  
Isolated Mitochondria ◽  
Golgi Vesicles ◽  
General Importance ◽  
Storage Body ◽  
Protein Granules

In the larva of the butterfly Calpodes ethlius, the fat body begins to store protein in the form of granules at about 30 to 35 hours before pupation, at a time when the endocuticle is being resorbed. At least two sorts of granule can be distinguished. The first granules to arise are those within vesicles of the Golgi complex. These may increase in size by incorporating material from microvesicles at their surface and by coalescence with one another. Later, at about 10 hours before pupation, another sort of granule arises by the isolation of regions of the endoplasmic reticulum (ER) within paired membranes derived from Golgi vesicles. Several of these ER isolation bodies coalesce, with fusion of their outer isolating membranes. The ribosomes and membranes may then disappear and the granules become indistinguishable from the protein granules formed from Golgi vesicles, or the ribosomes may remain and be embedded in dense crystalline protein, forming a storage body for both protein and RNA. Mitochondria are isolated within paired membranes in the same way as regions of the ER. The isolated mitochondria also coalesce in a similar manner. When the inner membranes are lost, the structure of a group of isolation bodies is indistinguishable from that of a cytolysome. Isolation within paired membranes, as described here, may be of general importance in segregating regions of massive lysis or massive sequestration.

Effects of Trichoderma on sexual reproduction of some species of Pythium and Phytophthora

1978 ◽  
Vol 56 (14) ◽  
pp. 1651-1654
Author(s):  
R. H. Haskins ◽  
N. R. Gardner
Keyword(s):  
Sexual Reproduction ◽  
Direct Contact ◽  
Phytophthora Cinnamomi ◽  
Apparent Effect ◽  
Trichoderma Spp ◽  
Volatile Products ◽  
Pythium Acanthicum

Pythium and Phytophthora cultures were subjected to volatile products from cultures of several Trichoderma spp., as well as to killed mycelium and extracts therefrom. Oospores were produced by Pythium acanthicum and P. arrhenomanes and by one strain of each of the compatible heterothallic pairs of P. sylvaticum and P. catenulatum tested, only in the presence of a suitable sterol. The volatile products of the Trichoderma spp. tested had no apparent effect on oospore production. Direct contact with Trichoderma mycelium, or fat-solvent extracts of such mycelium, resulted in oospore production by P. acanthicum. Such oospore production was likely due to the presence of sterols in the Trichoderma. Similarly, with the compatible pairs of Phytophthora cinnamomi tested, oospores were produced by paired cultures or, in some cases, by the 'A2' strains alone, only in the presence of a suitable sterol, whether or not volatile products from Trichoderma cultures were provided to the growing organisms.

FINE STRUCTURE IN DETACHED, SENESCING WHEAT LEAVES

1965 ◽  
Vol 43 (6) ◽  
pp. 747-755 ◽  
Author(s):  
Michael Shaw ◽  
M. S. Manocha
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Osmium Tetroxide ◽  
Mesophyll Cells ◽  
Laboratory Bench ◽  
Detached Leaves ◽  
Petri Dishes ◽  
Wheat Leaves ◽  
Cytoplasmic Ribosomes

Detached leaves of Little Club wheat were allowed to senesce on water or on kinetin (10 mg/l.) in petri dishes on the laboratory bench. Samples taken at intervals of 24 to 48 hours for 8 to 10 days were fixed in permanganate or osmium tetroxide, embedded, usually in araldite or epon, and examined by electron microscopy. Abnormalities were noted in the endoplasmic reticulum (ER) of the mesophyll cells 2 days after the leaves were detached; ER and cytoplasmic ribosomes were not present after 4 or 5 days. Swelling of the mitochondria and degeneration of the cristae, collapse of the chloroplast grana, and abnormalities in nuclear structure were noted after 3 days. Vacuolar contraction occurred in some cells after 4 days but the plasma membrane usually remained unbroken until the seventh or eighth day, by which time the mitochondria were no longer recognizable and most of the chloroplasts and nuclei had also disintegrated.Kinetin induced an increase in the amount of ER and ribosomes and markedly delayed the degeneration of cellular fine structure.

Ultrastructure de l'hyphe végétatif de Sclerotinia fructigena

1979 ◽  
Vol 57 (12) ◽  
pp. 1299-1313 ◽  
Author(s):  
L. Najim ◽  
G. Turian
Keyword(s):  
Endoplasmic Reticulum ◽  
Apicobasal Polarity ◽  
Apical Vesicles ◽  
Hyphal Tip

Vegetative hyphae of Sclerotinia (Monilia) fructigena (Ader and Ruhl) show a sharply polarized distribution of their organelles. In their tip, the "Spitzenkörper" made up of a microvesicular aggregate is well delimitated and surrounded by apical vesicles which can fuse with the plasmalemma. Excluded from the hyphal tip, mitochondria are elongated in the apicobasal polarity and in contact with numerous and often voluminous lipid globules. It appears that these lipid globules originate from the endomembranous system of the hyphae. The endoplasmic reticulum extends into pseudogolgi cisternae apparently generating apical vesicles. In the new hyphal branches, polarity seems to be initiated by the newly oriented endoplasmic reticulum from which originate microvesicles later aggregating into the new "Spitzenkörper." An elaborate system of microtubules also seems implicated in the further maintenance of the polarity of the growing hyphae. Microbodies with pseudocrystalline inclusions are also oriented according to the developmental polarity.

scholarly journals Spindle Dynamics during Meiotic Development of the Fungus Podospora anserina Requires the Endoplasmic Reticulum-Shaping Protein RTN1

mBio ◽  
2021 ◽  
Author(s):  
Antonio de Jesús López-Fuentes ◽  
Karime Naid Nachón-Garduño ◽  
Fernando Suaste-Olmos ◽  
Ariadna Mendieta-Romero ◽  
Leonardo Peraza-Reyes
Keyword(s):  
Endoplasmic Reticulum ◽  
Genetic Variation ◽  
Cell Division ◽  
Sexual Reproduction ◽  
Genetic Recombination ◽  
Podospora Anserina ◽  
Eukaryotic Evolution ◽  
Spindle Dynamics

Meiosis consists of a reductional cell division, which allows ploidy maintenance during sexual reproduction and which provides the potential for genetic recombination, producing genetic variation. Meiosis constitutes a process of foremost importance for eukaryotic evolution.

Uredospore development in Puccinia graminis

1969 ◽  
Vol 47 (12) ◽  
pp. 2061-2064 ◽  
Author(s):  
M. A. Ehrlich ◽  
H. G. Ehrlich
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Wall Layer ◽  
Tangential Section ◽  
Puccinia Graminis ◽  
Lipid Bodies ◽  
External Wall ◽  
Additional Information ◽  
Spine Development

The present paper reports a number of electron microscope observations on the protoplasm and walls of developing spores which provide additional information on uredospore wall and spine development and on the fine structure of organelles, particularly of mitochondria and endoplasmic reticulum and of lipid bodies in developing spores. Micrographs of partially extracted uredospore walls and of chromium-shadowed extracted sections demonstrate the architecture of the wall as seen in cross and tangential section. Three distinct wall zones are clearly visible with the external wall layer forming the boundary of the germinal pore.

Structural relations between nucleus and cytoplasm during mitosis in Nicotiana tabacum mesophyll

1969 ◽  
Vol 47 (4) ◽  
pp. 581-591 ◽  
Author(s):  
Katherine Esau ◽  
Robert H. Gill
Keyword(s):  
Endoplasmic Reticulum ◽  
Nicotiana Tabacum ◽  
Nuclear Envelope ◽  
Osmium Tetroxide ◽  
Ultrastructural Level ◽  
Early Prophase ◽  
Nuclear Region ◽  
Spindle Poles ◽  
Nicotiana Tabacum L ◽  
Cytoplasmic Ribosomes

The changes in relation between the nucleus and the cytoplasm associated with mitosis were explored at the ultrastructural level in the mesophyll of Nicotiana tabacum L. The material was fixed in glutaraldehyde – formaldehyde – osmium tetroxide. During interphase and early prophase the nucleoplasm can be distinguished from the cytoplasm by its lack of granules comparable to those interpreted as ribosomes in the cytoplasm. After the nuclear envelope is disrupted the nuclear region shows a population of ribosomes identical with that in the cytoplasm, that is, the nucleoplasm and the cytoplasm become indistinguishable. The nuclear envelope differs from the endoplasmic reticulum located in the cytoplasm by the presence of pores. Pieces of the disrupted nuclear envelope assume the same appearance as the endoplasmic reticulum although they remain localized around the nuclear region until metaphase. Eventually the remnants of the envelope are carried to the spindle poles and serve as a source of envelopes for the daughter nuclei. The larger organelles are excluded from the nuclei during development of their envelopes but units of endoplasmic reticulum and apparently some cytoplasmic ribosomes become trapped among the chromosomes. Later, the extranuclear components disappear, probably by being disassembled.

In Vitro Induction of Crystals of MT Protein by Vinblastine-Colcemid in Mouse Spermatids

1974 ◽  
Vol 32 ◽  
pp. 132-133
Author(s):  
John J. Wolosewick ◽  
John H. D. Bryan
Keyword(s):  
Endoplasmic Reticulum ◽  
Smooth Endoplasmic Reticulum ◽  
Nuclear Ring ◽  
Rough Er ◽  
Distal Direction ◽  
In Vitro Induction

Early in spermiogenesis the manchette is rapidly assembled in a distal direction from the nuclear-ring-densities. The association of vesicles of smooth endoplasmic reticulum (SER) and the manchette microtubules (MTS) has been reported. In the mouse, osmophilic densities at the distal ends of the manchette are the organizing centers (MTOCS), and are associated with the SER. Rapid MT assembly and the lack of rough ER suggests that there is an existing pool of MT protein. Colcemid potentiates the reaction of vinblastine with tubulin and was used in this investigation to detect this protein.

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