Aspects of the fine structure of the dauer larva of the nematode Caenorhabditis elegans

1979 ◽  
Vol 57 (4) ◽  
pp. 794-800 ◽  
Author(s):  
J. D. Popham ◽  
J. M. Webster
Keyword(s):  
Caenorhabditis Elegans ◽  
Body Wall ◽  
Toxic Chemicals ◽  
Intestinal Lumen ◽  
Intestinal Cells ◽  
Nematode Caenorhabditis Elegans ◽  
Golgi Bodies ◽  
Lateral Cord ◽  
Dauer Larva ◽  
Adverse Environmental Conditions

Examination of the ultrastructure of the dauer larva of Caenorhabditis elegans showed that cells in the lateral cord and body wall muscle had irregular profiles, few Golgi bodies, and cisternae of endoplasmic reticulum, but they contained abundant lipid and glycogen. These cells and the esophageal cells had mitochondria in the condensed conformation. The intestinal lumen was small and the brush border was so compact that individual microvilli were difficult to discern. Intestinal cells had cytosomes with irregular profiles and unhomogeneous matrices. The striated layer was absent from the cuticle covering the lips and papillae. These ultrastructural features are correlated with the dauer larva's low metabolic rate, its resistance to toxic chemicals and to adverse environmental conditions, and its ability to detect food and to feed soon after exposure to a hospitable environment.

Lysosomal and pseudocoelom routing protects Caenorhabditis elegans from ricin toxicity

Nematology ◽  
2003 ◽  
Vol 5 (3) ◽  
pp. 339-350 ◽  
Author(s):  
August Coomans ◽  
Myriam Claeys ◽  
Gaëtan Borgonie ◽  
Christopher Link
Keyword(s):  
Caenorhabditis Elegans ◽  
Intestinal Cells ◽  
Progeny Production ◽  
Nematode Caenorhabditis Elegans ◽  
Surface Receptors ◽  
C Elegans ◽  
Transmission Electron ◽  
A Chain ◽  
Golgi Network ◽  
Ricin A

AbstractThe resistance of the nematode Caenorhabditis elegans towards the highly potent toxin ricin has been studied. Incubation of C. elegans in ricin did not affect life span or progeny production. However, micro-injection of the ricin A-chain into the distal, syncitial gonad caused degeneration and sterility in test specimens, confirming that C. elegans ribosomes are sensitive. Using transmission electron microscopy, it was observed that ricin is effectively internalised into the intestinal cells. When pre-labelled with gold, the toxin reached only the lysosomes. When native toxin was used, the toxin was either routed to the lysosomes or underwent transcytosis to the pseudocoelomatic cavity and incorporation into embryos. None of the ricin reached either the trans Golgi network or the Golgi apparatus, considered essential for toxicity. The observed oral non-toxicity is therefore due to alternate sorting of the toxin, a mechanism not previously observed. The data indicate that, although ricin can opportunistically bind to, and be internalised by, cell surface receptors, these receptors are not sufficient to elicit toxicity.

scholarly journals Immunochemical localization of myosin heavy chain isoforms and paramyosin in developmentally and structurally diverse muscle cell types of the nematode Caenorhabditis elegans.

1987 ◽  
Vol 105 (6) ◽  
pp. 2763-2770 ◽  
Author(s):  
J P Ardizzi ◽  
H F Epstein
Keyword(s):  
Caenorhabditis Elegans ◽  
Muscle Cell ◽  
Body Wall ◽  
Muscle Cells ◽  
Cell Types ◽  
The Body ◽  
Myosin Heavy Chains ◽  
Nematode Caenorhabditis Elegans ◽  
Heavy Chains ◽  
Pharyngeal Muscles

The nematode Caenorhabditis elegans contains two major groups of muscle cells that exhibit organized sarcomeres: the body wall and pharyngeal muscles. Several additional groups of muscle cells of more limited mass and spatial distribution include the vulval muscles of hermaphrodites, the male sex muscles, the anal-intestinal muscles, and the gonadal sheath of the hermaphrodite. These muscle groups do not exhibit sarcomeres and therefore may be considered smooth. Each muscle cell has been shown to have a specific origin in embryonic cell lineages and differentiation, either embryonically or postembryonically (Sulston, J. E., and H. R. Horvitz. 1977. Dev. Biol. 56:110-156; Sulston, J. E., E. Schierenberg, J. White, and J. N. Thomson. 1983. Dev. Biol. 100:64-119). Each muscle type exhibits a unique combination of lineage and onset of differentiation at the cellular level. Biochemically characterized monoclonal antibodies to myosin heavy chains A, B, C, and D and to paramyosin have been used in immunochemical localization experiments. Paramyosin is detected by immunofluorescence in all muscle cells. Myosin heavy chains C and D are limited to the pharyngeal muscle cells, whereas myosin heavy chains A and B are localized not only within the sarcomeres of body wall muscle cells, as reported previously, but to the smooth muscle cells of the minor groups as well. Myosin heavy chains A and B and paramyosin proteins appear to be compatible with functionally and structurally distinct muscle cell types that arise by multiple developmental pathways.

scholarly journals Purified thick filaments from the nematode Caenorhabditis elegans: evidence for multiple proteins associated with core structures.

1988 ◽  
Vol 106 (6) ◽  
pp. 1985-1995 ◽  
Author(s):  
H F Epstein ◽  
G C Berliner ◽  
D L Casey ◽  
I Ortiz
Keyword(s):  
Caenorhabditis Elegans ◽  
Body Wall ◽  
Gradient Centrifugation ◽  
Blue Staining ◽  
Nematode Caenorhabditis Elegans ◽  
C Elegans ◽  
Thick Filaments ◽  
Cell Biol ◽  
Associated Proteins ◽  
Body Wall Muscles

The thick filaments of the nematode, Caenorhabditis elegans, arising predominantly from the body-wall muscles, contain two myosin isoforms and paramyosin as their major proteins. The two myosins are located in distinct regions of the surfaces, while paramyosin is located within the backbones of the filaments. Tubular structures constitute the cores of the polar regions, and electron-dense material is present in the cores of the central regions (Epstein, H.F., D.M. Miller, I. Ortiz, and G.C. Berliner. 1985. J. Cell Biol. 100:904-915). Biochemical, genetic, and immunological experiments indicate that the two myosins and paramyosin are not necessary core components (Epstein, H.F., I. Ortiz, and L.A. Traeger Mackinnon. 1986. J. Cell Biol. 103:985-993). The existence of the core structures suggests, therefore, that additional proteins may be associated with thick filaments in C. elegans. To biochemically detect minor associated proteins, a new procedure for the isolation of thick filaments of high purity and structural preservation has been developed. The final step, glycerol gradient centrifugation, yielded fractions that are contaminated by, at most, 1-2% with actin, tropomyosin, or ribosome-associated proteins on the basis of Coomassie Blue staining and electron microscopy. Silver staining and radioautography of gel electrophoretograms of unlabeled and 35S-labeled proteins, respectively, revealed at least 10 additional bands that cosedimented with thick filaments in glycerol gradients. Core structures prepared from wild-type thick filaments contained at least six of these thick filament-associated protein bands. The six proteins also cosedimented with thick filaments purified by gradient centrifugation from CB190 mutants lacking myosin heavy chain B and from CB1214 mutants lacking paramyosin. For these reasons, we propose that the six associated proteins are potential candidates for putative components of core structures in the thick filaments of body-wall muscles of C. elegans.

scholarly journals Muscle cell attachment in Caenorhabditis elegans.

1991 ◽  
Vol 114 (3) ◽  
pp. 465-479 ◽  
Author(s):  
R Francis ◽  
R H Waterston
Keyword(s):  
Caenorhabditis Elegans ◽  
Basement Membrane ◽  
Muscle Cell ◽  
Body Wall ◽  
Cell Attachment ◽  
Muscle Cells ◽  
The Body ◽  
Nematode Caenorhabditis Elegans ◽  
Hypodermal Cell ◽  
Body Wall Muscles

In the nematode Caenorhabditis elegans, the body wall muscles exert their force on the cuticle to generate locomotion. Interposed between the muscle cells and the cuticle are a basement membrane and a thin hypodermal cell. The latter contains bundles of filaments attached to dense plaques in the hypodermal cell membranes, which together we have called a fibrous organelle. In an effort to define the chain of molecules that anchor the muscle cells to the cuticle we have isolated five mAbs using preparations enriched in these components. Two antibodies define a 200-kD muscle antigen likely to be part of the basement membrane at the muscle/hypodermal interface. Three other antibodies probably identify elements of the fibrous organelles in the adjacent hypodermis. The mAb IFA, which reacts with mammalian intermediate filaments, also recognizes these structures. We suggest that the components recognized by these antibodies are likely to be involved in the transmission of tension from the muscle cell to the cuticle.

The buccal capsule of Caenorhabditis elegans (Nematoda: Rhabditoidea): an ultrastructural study

1981 ◽  
Vol 59 (10) ◽  
pp. 1952-1961 ◽  
Author(s):  
K. A. Wright ◽  
J. N. Thomson
Keyword(s):  
Caenorhabditis Elegans ◽  
Body Wall ◽  
Buccal Capsule ◽  
Nematode Caenorhabditis Elegans ◽  
Free Living ◽  
Dense Granules ◽  
Free Living Nematode ◽  
Section Electron ◽  
Serial Section Electron Microscopy ◽  
Esophageal Muscle

The buccal capsule of the free-living nematode Caenorhabditis elegans has been analysed by serial section electron microscopy. Whereas the regions classically identified in the rhabditid buccal capsule can be distinguished, the cuticle lining does not constitute separate cuticular plates, but rather, structural–functional differentiations within a cuticle continuous with that of the esophagus. Only the lip region (cheilostom) is lined by body wall cuticle. The prostom cuticle is underlain by two rings of syncytial arcade cytoplasm connected to nine cell bodies. The mesostom cuticle is underlain by the nonmuscular epithelial cells of the esophagus, whereas the cuticle of the metastom and telostom is underlain by esophageal muscle cells m1 and m2. During moulting, buccal cuticle is produced later than body cuticle and its formation is characterized by accumulation of dense granules in both arcade and esophageal cytoplasm. It is concluded that the buccal capsule should be considered as "astomatous" in the terminology of K. A. Wright.

scholarly journals Regulation of proteinase levels in the nematode Caenorhabditis elegans. Preferential depression by acute or chronic starvation

1989 ◽  
Vol 264 (1) ◽  
pp. 161-165 ◽  
Author(s):  
J M Hawdon ◽  
S W Emmons ◽  
L A Jacobson
Keyword(s):  
Caenorhabditis Elegans ◽  
Cathepsin D ◽  
Feeding Behaviour ◽  
Intestinal Cells ◽  
Wild Type ◽  
Nematode Caenorhabditis Elegans ◽  
Protein Substrates ◽  
Alternative Protein ◽  
Acute Starvation ◽  
Beta Glucosidase

Acute starvation of the wild-type of the nematode Caenorhabditis elegans depresses the level of cathepsin D by 65% within 4-8 h and the level of the thiol cathepsins Ce1 and Ce2 to about the same extent after 24 h. There is no parallel loss of lysosomal beta-glucosidase or beta-hexosaminidase activities. In strains which are chronically starved as a result of mutations which compromise feeding behaviour (unc-52) or nutrient uptake into the intestinal cells (daf-4), cathepsin D levels are decreased to about 15% of the level in fully fed wild-type animals. We suggest that the decline in the cathepsin D level results from autodigestion when alternative protein substrates are depleted in the lysosomes.

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