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[
Worm Breeder's Gazette,
1976]
We have been working on the purification of native myofilament proteins from wild-type C. elegans and have determined some of their biochemical and structural properties. Procedures have been developed for isolating myosin, paramyosin, actin and tropomyosin at greater than 90% purity, from the same batch of worms. Nematode myosin. Our purified myosin is, presumably, a mixture of all nematode classes of myosin. The properties described below therefore represent average properties of all myosins. We are currently comparing the myosins of N2 with E190 and E675. In E190, the concentration of unc 54 myosin seems insignificant, while E675 contains an altered unc 54 product. Properties: 1) Besides the 210,000 heavy chains, it contains 2 light chain classes: 18,000 and 16,000 daltons. Both classes are present in E190 and E675. 2) The Ca2+-ATPase (10mM CaCl2) is comparable with rabbit skeletal muscle myosin. 3) The Mg2+-ATPase (2mM MgCl2 - 0.2mM CaCl2) is stimulated up to twofold by rabbit actin. This activity is very labile. 4) The myosin forms either very long filaments with no apparent polarity, or short, very compact bipolar structures, when ionic strength is lowered to 0.1M in 10mM MgCl2. The type of aggregate depends on whether the sample is precipitated slowly by dialysis, or rapidly by dilution. Dialysis of nematode myosin and paramyosin together yields filaments with a paramyosin core and a surface coating of myosin. Nematode tropomyosin. This is unusual in having a higher molecular weight (40,000 by SDS gel electrophoresis) than has been reported for any other tropomyosin. It forms paracrystals with a 38.0-39.0nm repeat, but a different molecular packing to rabbit skeletal muscle tropomyosin. Calcium regulation of contraction in C. elegans. Activation of the ATPase of purified nematode myosin by rabbit actin is Ca2+-requiring. Similarly, activation of rabbit heavy meromyosin (calcium independent) by crude nematode thin filaments is stimulated 3-fold by Ca2+. Nematode muscle apparently contains both thick and thin filament linked calcium regulatory systems.
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[
Cell,
1977]
Myosin and paramyosin have been purified from the nematode, Caenorhabditis elegans. The properties of the myosin in general resemble those of other myosins. The native molecule is a dimer of heavy (210,000 dalton) polypeptide chains and contains 18,000 and 16,000 dalton light chains. When rapidly precipitated from solution, it forms small, bipolar aggregates, about 150 nm long, consistent with the expected molecular structure of a rigid rod with a globular head region at one end. Its ATPase activity is stimulated by Ca2+ and EDTA. The myosin binds to F actin in a polar and ATP-sensitive manner, and the Mg2+-ATPase is activated by either F actin or nematode thin filaments. Dialysis of myosin to low ionic strength produces very long filaments. When a myosin-paramyosin mixture is dialyzed under the same conditions, co-filaments form which consist of a myosin cortex, surrounding a paramyosin core. Some properties of myosins from the mutants E675 and E190, which have functionally and structurally altered body wall muscles, are compared with those of wild-type myosin. These myosins behave normally in in vitro tests. The implications of these results are discussed in terms of the myosin heavy chain composition.
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[
Biochemistry,
1977]
Calcium regulation of actomyosin activity in the nematode, Caenorhabditis elegans, has been studied with purified proteins and crude thin filaments. Actin and tropomyosin have been purified from C. elegans and shown to be similar in most respects to actin and tropomyosin from rabbit skeletal muscle. The actin comigrates with rabbit actin on polyacrylamide-sodium dodecyl sulfate gel electrophoresis, forms similar filaments and paracrystals, and activates the Mg2+-ATPase of rabbit myosin heads as efficiently as rabbit actin. Nematode tropomyosin has a greater apparent molecular weight (estimated by mobility on polyacrilamide-sodium dodecyl sulfate gels) than the rabbit protein, yet it forms Mg2+-paracrystals with a slightly shorter periodicity. Native thin filaments extracted from nematodes activate rabbit myosin subfragment 1 Mg2+-ATPase in a calcium sensitive manner; the extent of activation is threefold greater in 0.2 mM CaCl2 than in the absence of calcium. This observation suggests that the thin filaments contain components which are functionally equivalent to vertebrate troponins. Calcium is also required for maximal activation of the Mg2+-ATPase of purified nematode myosin and thin filament-linked calcium regulatory systems. The origin of the actin, tropomyosin, and myosin from different tissues and the use of genetic analysis to answer questions about assembly and function in vivo are discussed.
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[
Southeast Asian J Trop Med Public Health,
2006]
We are reporting a case of an eye lesion caused by an adult Brugia malayi. The patient was a 3-year-old Chinese boy from Kemaman District, Terengganu, Peninsular Malaysia. He presented with a one week history of redness and palpebral swelling of his right eye. He claimed that he could see a worm in his right eye beneath the conjunctiva. He had no history of traveling overseas and the family kept dogs at home. He was referred from Kemaman Hospital to the eye clinic of Hospital Tengku Ampuan Afzan, Kuantan, Pahang, Malaysia. On examination by the ophthalmologist, he was found to have a subconjunctival worm in his right eye. Full blood count revealed eosinophilia (10%). Four worm fragments, each about 1 cm long were removed from his right eye under general anesthesia. A thick blood smear stained with Giemsa was positive for microfilariae of Brugia malayi. A Brugia Rapid test done was positive. He was treated with diethylcarbamazine.
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[
Genetics,
2015]
Ellsworth Dougherty (1921-1965) was a man of impressive intellectual dimensions and interests; in a relatively short career he contributed enormously as researcher and scholar to the biological knowledge base for selection of Caenorhabditis elegans as a model organism in neurobiology, genetics, and molecular biology. He helped guide the choice of strains that were eventually used, and, in particular, he developed the methodology and understanding for the nutrition and axenic culture of nematodes and other organisms. Dougherty insisted upon a concise terminology for culture techniques and coined descriptive neologisms that were justified by their linguistic roots. Among other contributions, he refined the classification system for the Protista.
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[
Curr Biol,
2004]
Jonathan Hodgkin graduated from Oxford in 1971 and then did a PhD with Sydney Brenner at MRC LMB in Cambridge, studying behavioural genetics in the nematode Caenorhabditis elegans. Later, after a couple of years working with myxobacteria as a postdoc in Dale Kaiser''s lab at Stanford, he returned to LMB as a staff member, where he remained for most of the subsequent two decades. In the year 2000, he moved to Oxford as Professor of Genetics in the Department of Biochemistry, switching his major research interests from developmental genetics and sex determination to the study of host-pathogen interactions in the worm. For the past ten years, he has acted as curator of the C. elegans genetic map and gene nomenclature, and he is currently President of the Genetics Society of Great Britain.
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[
Nature,
1997]
Who scapes the lurking sepent's mortal sting? Not he that sets his foot upon her back. Even the smallest of worms will turn, when trodden on.
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[
Worm Breeder's Gazette,
1992]
EXPRESSION AND LOCALIZATION OF THE cha-l AND
unc-17 GENE PRODUCTS He-ping Han, Janet Duerr, and Jim Rand, Oklahoma Medlcal Research Foundation, Oklahoma Clty, OK 73104
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[
The New York Times,
1997]
His tall figure bent over a computer screen in his laboratory at the Massachusetts General Hospital, Dr. Gary Ruvkun rummages through a distant genetic data base for matches to a gene he believes is involved in diabetes. ?You learn how to read these as they are ratcheting by,? he says, while lines of data streak up his screen. ?I think MTV is good training.?
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[
Autophagy,
2024]
Professor Richard (Rick) Morimoto is the Bill and Gayle Cook Professor of Biology and Director of the Rice Institute for Biomedical Research at Northwestern University. He has made foundational contributions to our understanding of how cells respond to various stresses, and the role played in those responses by chaperones. Working across a variety of experimental models, from <i>C</i>. <i>elegans</i> to human neuronal cells, he has identified a number of important molecular components that sense and respond to stress, and he has dissected how stress alters cellular and organismal physiology. Together with colleagues, Professor Morimoto has coined the term "proteostasis" to signify the homeostatic control of protein expression and function, and in recent years he has been one of the leaders of a consortium trying to understand proteostasis in healthy and disease states. I took the opportunity to talk with Professor Morimoto about proteostasis in general, the aims of the consortium, and how autophagy is playing an important role in their research effort.