Yu, Hsiang et al. (2013) International Worm Meeting "Comparisons of three C. elegans DNase II activities in vitro and in vivo."

Yu, Hsiang, Lo, Szecheng J.

[International Worm Meeting, 2013]

DNase II is an acidic DNase which plays an important role in the degradation of apoptotic cell DNA from a wide spectrum of animals. In C. elegans, three DNase II genes, nuc-1, crn-6 and crn-7, are identified, in contrast two DNase II (a and b) are found in mammals. There are three waves of cell apoptosis, embryonic, larval stage and oogenesis during C. elegans development. The role of nuc-1 and crn-6 in embryonic and larval development have been demonstrated; however enzymatic activities of three DNase II remain obscure. Here, we report three methods for detecting NUC-1, CRN-6 and CNR-7 activities in vitro and in vivo. First, using metachromatic agar-diffusion assay (MADA), DNase II activity in embryonic extracts from wild-type and mutant animals were examined. Results showed that NUC-1 had the highest DNase II activity while CRN-6 and CRN-7 exhibited 10 fold lower activity than NUC-1. Second, recombinant proteins of GST fusion with NUC-1, CRN-6 and CRN-7 were generated in E. coli. The enzymatic activity of purified DNase II fusion proteins were analyzed using non-denaturing PAGE. DNA digestion by NUC-1 and CRN-7 was demonstrated in gels, but little or no DNA digestion by CRN-6. Thirdly, a technique which directly labels the DNase II-type breaks with a fluorescent probe was applied to detect the DNA fragmentation in embryos. Results showed that the fluorescent signals in nuc-1 mutant are twice less than those in wild-type, crn-6 and crn-7 embryos. This result is consistent to the TUNEL assay in embryo as demonstrated before. In the future, the technique of direct libeling DNase II-type breaks can be employed to study roles of three DNase II in germ-line apoptosis.

Palikaras, Konstantinos et al. (2021) International Worm Meeting "Mitochondrial defects manifest an early pathogenic event undermining organismal fitness in a Tauopathy model"

Akbari, Mansour, Achanta, Kavya, Bohr, Vilhelm, Palikaras, Konstantinos

[International Worm Meeting, 2021]

Battling age-associated neurodegenerative pathologies and their pervasive societal impact, is a global enterprise. Alzheimer's disease (AD) is the most common dementia affecting elderly population and there is not any efficient therapeutic strategy until now. Age-dependent impairment of mitochondrial homeostasis is a common feature in evolutionary divergent organisms and is associated with neuronal loss and cognitive decline in AD. However, whether mitochondrial dysfunction is a culprit or bystander of AD pathology remain still elusive. Here, we utilized transgenic nematodes expressing the full length of wild type Tau (Tauwt-lo) in neuronal cells and monitored several aspects of mitochondrial morphology. Although Tauwt-lo expressing nematodes do not present Tau aggregates during larval stages, they display increased mitochondrial damaged and locomotion defects. Interestingly, calcium chelating agents restores mitochondrial activity and motility in Tauwt-lo expressing larvae suggesting that cytoplasmic calcium elevation mediates neuronal impairment. Our findings in their totality suggest that mitochondrial damage is an early pathogenic event of AD that is taking place before Tau aggregation undermining neuronal homeostasis and organismal fitness during aging.

Chen, Yi-Yin et al. (2009) International Worm Meeting "Expression of hepatitis B viral antigens induces growth retardation of C. elegans."

Lo, Szecheng J., Chen, Yi-Yin, Hung, Wei-Ning, Lee, Li-Wei

[International Worm Meeting, 2009]

Hepatitis B virus (HBV) is a human hepatotropic virus. Its infection is associated with various liver diseases, including acute and chronic hepatitis and hepatocelluar carcinoma. Pathogenesis induced by HBV remains elusive. Here, we report HBV surface antigen (HBsAg) expression in various tissues of C. elegans caused different degree of retardation and reduction of brood-size. Transgenic worms expressing major HBsAg driven by the fibrillarin (fib-1) promoter had the most pronounced effect on brood-size and growth rate; those expressing major HBsAg driven by ges-1 or myo-2 had the moderated effect; those expressing HBsAg by neuron promoter (mec-7) had no significant effect. Since in transgenic mouse model and human cell line have demonstrated that the expression of HBsAg induced ER-stress, the effect of lower brood-size and growth retardation caused by HBsAg expression in pharyngeal and intestinal cells might be also resulted from ER-stress. To determine the temporal effect of HBsAg, a heat-shock induction system was employed. Transgenic worms expressing HBsAg at L4 stage had the effect while those HBsAg expressing in L1, L2 or L3 worms had less effect. Transgenic worms expressing another HBV core antigen (HBcAg), which is located at the nucleus, also caused brood-size reduction. How this antigen reduced brood-size remains to be investigated.

McGhee JD (1987) Biochemistry "Purification and characterization of a carboxylesterase from the intestine of the nematode Caenorhabditis elegans."

McGhee JD

[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].

Yang, Hung-Chi et al. (2013) International Worm Meeting "Glucose 6-phosphate dehydrogenase (G6PD) deficiency impairs early embryogenesis in C. elegans."

Ou, Meng-Hsin, Chiu, Daniel Tsun-Yee, Yang, Hung-Chi, Lo, Szecheng J.

[International Worm Meeting, 2013]

Human glucose 6-phosphate dehydrogenase (G6PD) deficiency, also called favism, is manifested mainly by hemolytic anemia. In a mouse model, severe G6PD deficiency causes embryonic lethality. Using the established G6PD-knockdown Caenorhabditis elegans (C. elegans) animal model (Yang et al. Cell Death & Disease, 2013 in press), we seek to go beyond cellular physiology and delineate the role of G6PD in embryonic development. Under DIC microscopy, embryos derived from G6PD-knockdown C. elegans (refers to G6PD-knockdown embryos) exhibited drastic morphological alterations upon challenge with osmotic stress. Such embryos also demonstrated differential permeability to small molecule dyes. Since G6PD knockdown causes severe hatching defect, we tested the hypothesis that impaired early embryogenesis caused by G6PD deficiency contributes to defective hatching. Compared with mock embryos, a portion (10%) of G6PD-knockdown embryos showed symmetric division at two-cell stage. More importantly, compared with the hallmark events of early embryogenesis in mock embryos, G6PD-knockdown embryos (one-cell to four-cell stage) exhibited differential embryonic defects. The mild defects (type 1) included absence of perivitelline space, failure of forming cortical ruffling and pseudocleavage, the maternal and paternal pronuclei fused centrally, polarity defect in first division and synchronous cytokinesis in second division. In addition to these morphological defects, type 1 embryos required a longer time course during early embryonic development (average 42 minutes from one-cell to four-cell stage) compared to mock embryos (average 29 minutes). The severe defects (type 2) included the maternal and paternal pronuclei which fused slower than that of mock embryos and arrested at one-cell stage for more than 40 minutes as compared to mock embryos (average 17 minutes from one-cell to two-cell stage). Taken together, these findings suggest that G6PD deficiency impairs early embryogenesis in C. elegans.

Murakami S et al. (1999) Curr Biol "Life extension and stress resistance in Caenorhabditis elegans modulated by the tkr-1 gene."

Johnson TE, Murakami S

[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).

Ramos CG et al. (2014) J Bacteriol "Retraction for Ramos et al., MtvR is a global small noncoding regulatory RNA in Burkholderia cenocepacia."

Feliciano JR, da Costa PJ, Ramos CG, Grilo AM, Leitao JH

[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.

Nillegoda NB et al. (2015) Nature "Crucial HSP70 co-chaperone complex unlocks metazoan protein disaggregation."

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.

Miller DM et al. (1992) Worm Breeder's Gazette "unc-4 LacZ Expression in A-Type Motor Neurons"

Miller DM, Niemeyer CJ

[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

Sommer RJ et al. (1994) Worm Breeder's Gazette "Evolution of Vulva-Formation: Part II: Species With a Central Vulva"

Sommer RJ, Sternberg PW

[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