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[
Worm Breeder's Gazette,
1994]
mab-5 Expression Repeatedly Switches ON and OFF in the V5 Lineage S. Salser and C. Kenvon, UCSF, San Francisco, CA. 94143
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[
Worm Breeder's Gazette,
1994]
Activity of the polyray-1 maintenance gene must be overcome to allow for correct temporal expression of HOM-C genes Julin Maloof and Cynthia Kenyon, Dept of Biochemistry, UCSF, San Francisco, CA 94143 0554
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[
International Worm Meeting,
2021]
C. elegans arrest post-embryonic development as a strategy to survive unfavorable conditions. After hatching in the absence of food, larvae arrest at the first larval stage (L1). Blast cell divisions occurring during L1 cease and cells enter quiescence. Arrested L1s can survive several weeks without food and show increased resistance to stress. L1 larvae arrested for long periods undergo a process of aging during which animals accumulate different signs of aging. When fed, arrested L1s resume development after a process of recovery where aging is reversed. There is a direct correlation between the higher level of ageing during prolonged arrest and the time needed to recover. We have observed that prolonged L1 arrest delays specifically the reactivation of blast cell divisions. Once postembryonic development is resumed, the subsequent events occur normally. Insulin signaling modulates the rate of L1 ageing affecting proliferative potential after quiescence, what directly impacts recovery time. Different endogenous and exogenous factors can directly influence recovery after arrest. We show that variable yolk provisioning to the embryos as a consequence of maternal age confers inter-individual variability in recovery after quiescence of genetically identical animals. Larvae coming from older mothers recover faster. Furthermore, we have revealed that density also affects recovery from L1 quiescence by modulating insulin signaling. L1 larvae arrested at high density show sustained DAF-16 activation during arrest, and reduced expression of the insulin-like peptide DAF-28. The effect of density is mediated by small soluble compounds of unknown nature. Finally, we have identified the disaccharide trehalose as one of these molecules. Trehalose mediates the communication between arrested L1 larvae and modulates the insulin signaling in the animals that sense the signal. Overall, we have contributed to the consolidation of L1 arrest as an in vivo model to study the mechanisms involved in cell quiescence, and the role of insulin signaling in the process.
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[
Biochemistry,
1987]
The major intestinal esterase from the nematode Caenorhabditis elegans has been purified to essential homogeneity. Starting from whole worms, the overall purification is 9000-fold with a 10% recovery of activity. The esterase is a single polypeptide chain of Mr 60,000 and is stoichiometrically inhibited by organophosphates. Substrate preferences and inhibition patterns classify the enzyme as a carboxylesterase (EC 3.1.1.1), but the physiological function is unknown. The sequence of 13 amino acid residues at the esterase N- terminus has been determined. This partial sequence shows a surprisingly high degree of similarity to the N-terminal sequence of two carboxylesterases recently isolated from Drosophila mojavensis [Pen, J., van Beeumen, J., & Beintema, J. J. (1986) Biochem. J. 238, 691-699].
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[
IDrugs,
2010]
CHI''s Seventh Annual Conference on High-Content Analysis (HCA), held in San Francisco, incorporated topics covering new developments in the field of HCA, including hardware and software updates, new biological models for HCA and pathway analysis. This conference report highlights selected presentations on the use of HCA for the characterization of stem cells, cell-colony analysis, the validation of disease models and the identification of antiparasitic compounds.
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[
Curr Biol,
1999]
In this Brief Communication, which appeared in the 14 September 1998 issue of Current Biology, the UV dose was reported erroneously. The dose reported was 20 J/m2 but the actual dose used was 0.4 J/cm2. Also, the gene formally referred to as
tkr-1 has since been renamed
old-1 (overexpression longevity determination).
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[
J Bacteriol,
2014]
Volume 195, no. 16, p. 35143523, 2013. A number of problems related to images published in this paper have been brought to our attention. Figure 1D contains duplicated images in lanes S and LE, and Fig. 4D and 6B contain images previously published in articles in this journal and in Microbiology and Microbial Pathogenesis, i.e., the following: C. G. Ramos, S. A. Sousa, A. M. Grilo, J. R. Feliciano, and J. H. Leitao, J. Bacteriol. 193:15151526, 2011. doi:10.1128/JB.01374-11. S. A. Sousa, C. G. Ramos, L. M. Moreira, and J. H. Leitao, Microbiology 156:896908, 2010. doi:10.1099/mic.0.035139-0. C. G. Ramos, S. A. Sousa, A. M. Grilo, L. Eberl, and J. H. Leitao, Microb. Pathog. 48:168177, 2010. doi: 10.1016/j.micpath.2010.02.006. Therefore, we retract the paper. We deeply regret this situation and apologize for any inconvenience to the editors and readers of Journal of Bacteriology, Microbial Pathogenesis, and Microbiology.
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Berynskyy M, Morimoto RI, Bukau B, Stengel F, Kirstein J, Szlachcic A, Arnsburg K, Stank A, Scior A, Nillegoda NB, Gao X, Guilbride DL, Aebersold R, Wade RC, Mayer MP
[
Nature,
2015]
Protein aggregates are the hallmark of stressed and ageing cells, and characterize several pathophysiological states. Healthy metazoan cells effectively eliminate intracellular protein aggregates, indicating that efficient disaggregation and/or degradation mechanisms exist. However, metazoans lack the key heat-shock protein disaggregase HSP100 of non-metazoan HSP70-dependent protein disaggregation systems, and the human HSP70 system alone, even with the crucial HSP110 nucleotide exchange factor, has poor disaggregation activity in vitro. This unresolved conundrum is central to protein quality control biology. Here we show that synergic cooperation between complexed J-protein co-chaperones of classes A and B unleashes highly efficient protein disaggregation activity in human and nematode HSP70 systems. Metazoan mixed-class J-protein complexes are transient, involve complementary charged regions conserved in the J-domains and carboxy-terminal domains of each J-protein class, and are flexible with respect to subunit composition. Complex formation allows J-proteins to initiate transient higher order chaperone structures involving HSP70 and interacting nucleotide exchange factors. A network of cooperative class A and B J-protein interactions therefore provides the metazoan HSP70 machinery with powerful, flexible, and finely regulatable disaggregase activity and a further level of regulation crucial for cellular protein quality control.
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[
Worm Breeder's Gazette,
1992]
unc-4 LacZ expression in A-type motor neurons David M. Miller and Charles J. Niemeyer, Dept. of Cell Biology, Duke Univ. Medical Ctr, Durham, NC 27710
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[
Worm Breeder's Gazette,
1994]
Evolution of vulva-formation: Part II: Species with a central vulva Ralf J. Sommer & Paul W. Sternberg, California Institute of Technology, Division of Biology 156-29, Pasadena, CA 91125