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[
J Parasitol,
1994]
Shipment of infective-stage filarial larvae (L3s) usually has been accomplished by transporting living infected vectors or L3s cryopreserved in liquid nitrogen. Our objective was to find culture conditions for transporting L3s that would promote survival of Brugia malayi larvae without altering their capacity to infect susceptible animals. In preliminary studies we observed that Ham's nutrient mixture F-12, with antibiotics and 1% fetal calf serum, could support L3s without apparent development for at least 10 days. In order to evaluate the effect of culture temperatures on infectivity, fresh L3s were divided into groups that were either immediately injected into jirds (infectivity control) or incubated for 24, 48, or 120 hr in tightly sealed tubes maintained horizontally at either 0 C, 20 C, or 37 C, before they were injected into jirds. Necropsies were performed on the jirds 120-130 days after injection to recover and count adult worms. Levels of microfilaremia were also determined. We found that L3s held overnight at 0 C, although apparently viable, were unable to survive in jirds. However, larvae kept at 20 C and 37 C produced patent infections with adult worms in normal locations even after 120 hr of in vitro cultivation. There was no statistical difference in mean worm recovery or size of worms from jirds infected with freshly harvested L3s and jirds injected with larvae that were maintained overnight at 20 C or 37 C. When cultured L3s were shipped from Michigan to Connecticut by overnight air courier, along with infected living mosquitos, the L3s appeared to be 99% viable upon arrival. L3s shipped in F-12 produced patent infections in C.B.-17 scid/scid mice with worm recoveries comparable to those observed in mice injected with L3s freshly obtained from shipped mosquitos.
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[
Int J Parasitol,
2003]
Most of the recent evidence suggests that the avermectin/milbemycin family of anthelmintics act via specific interactions with glutamate-gated chloride channels. These channels are encoded by a small family of genes in nematodes, though the composition of the gene family and the function of the individual members of the family may vary between species. We review our current knowledge concerning the properties of the glutamate-gated chloride channels from Caenorhabditis elegans and the related parasite, Haemonchus contortus. We conclude that the biological effects of the avermectins/milbemycins can be largely explained by the known pharmacology and distribution of the glutamate-gated chloride channels and that differences between the glutamate-gated chloride channels from different nematodes may underlie species-specific variations in anthelmintic action.
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[
Int J Parasitol,
2004]
Dirofilaria immitis is a filarial nematode that infects dogs and causes cardiopulmonary disease. The most effective way of controlling the infection is by chemoprophylaxis, using members of the avermectin/milbemycin (A/M) class of anthelmintics, which includes ivermectin; these drugs act at invertebrate glutamate-gated chloride channels (GluCl). We have cloned two cDNAs encoding D. immitis GluCl subunits and demonstrated that at least one may be an important molecular target for the A/Ms in vivo. The subunits are orthologues of the alternatively spliced GluClalpha3A and alpha3B subunits (encoded by the
avr-14 gene) previously identified in Caenorhabditis elegans and in Haemonchus contortus. Although the alternative splicing of
avr-14 is conserved across the species, the processing of the mature GluClalpha3A mRNA differs in D. immitis compared to C. elegans and H. contortus. Two-electrode voltage clamp recordings were made from Xenopus oocytes injected with subunit-specific cRNAs. The DiGluClalpha3B subunit formed channels that were gated by l-glutamate (1-100 mM) and ivermectin (1 microM). Oocytes injected with DiGluClalpha3A cRNA failed to respond to l-glutamate. The qualitative responses obtained were consistent with the pharmacology observed for the GluClalpha3 subunits from C. elegans and H. contortus.
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[
Am J Trop Med Hyg,
1985]
Vaccination of inbred jirds (Meriones unguiculatus) with 60cobalt radiation-attenuated Brugia malayi infective stage larvae (L3) protected against homologous challenge given either subcutaneously (sc) or by the intraperitoneal (ip) route. Groups of jirds vaccinated once sc with 75, 15 Krad L3 showed from 69% to 91% reduction in recovered worms after ip challenge infection compared to infection in non-vaccinated control jirds, while 75% reduction in mean worm burden was seen in jirds receiving sc challenge infection. A single sc vaccination with 75, 10 or 20 Krad L3 produced no protection (10 Krad) and 64% reduction in recovered worms (20 Krad). Therefore the 15 Krad dose appeared to be best. A marked increase in anti-B. malayi antibody in vaccinated jirds was seen (by ELISA) immediately after challenge infection and an immunofluorescence assay showed that L3 incubated in serum from vaccinated jirds were completely and uniformly covered with specific antibody. Eosinophil-rich granulomas containing dead and moribund L3 were recovered from vaccinated jirds. This model of protective immunity in a Brugia-susceptible small rodent may provide a useful system for identification of molecularly defined filarial-protective immunogens.
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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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[
Aging, Metabolism, Stress, Pathogenesis, and Small RNAs, Madison, WI,
2010]
The FoxO transcription factor DAF-16 regulates a wide range of organismal functions: it is involved in C. elegans development and reproduction, in stress response and life span regulation. Association of DAF-16 with diverse binding partners might be crucial for mediating these heterogeneous functions (1-4). To identify DAF-16 regulators we established a biochemical approach for the purification of DAF-16 associated proteins. DAF-16 was fused to various epitop-tags. On the basis of a reporter assay it was analyzed whether the tagged DAF-16 versions were transcriptionally active and a dauer assay was used to test for their physiological activity in worms. A functional tagged DAF-16 variant was used for the generation of transgenic worms. DAF-16 protein complexes were isolated by tandem affinity purification and potential DAF-16 binding partners were identified by tandem mass-spectrometry (MudPIT). In an additional, reporter based screen DAF-16 co-regulators are currently validated and their potential roles in dauer formation, stress resistance and longevity are currently being pursued. We will discuss their identity and potential functions in insulin/IGF-1 signaling. (1): Essers MA. et al., Science. 2005; 308(5725): 1181-1184; (2): Wolff, S. et al., Cell. 2006; 124(5): 1039-1053; (3): Berdichevsky, A. et al., Cell. 2006; 125(6): 1165-1177; (4): Li, J. et al., PLoS Biol. 2008; 6(9): 1870-1886. This work was supported in part by the Austrian Science Fund (FWF, grant J2734) and by a grant from the NIH.
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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