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[
Science,
1997]
Previous genetic studies of the nematode Caenorhabditis elegans identified three important components of the cell death machinery. CED-3 and CED-4 function to kill cells, whereas CED-9 protects cells from death. Here CED-9 and its mammalian homolog Bcl-xL (a member of the Bcl-2 family of cell death regulators) were both found to interact with and inhibit the function of CED-4. In addition, analysis revealed that CED-4 can simultaneously interact with CED-3 and its mammalian counterparts interleukin-1beta-converting enzyme (ICE) and FLICE. Thus, CED-4 plays a central role in the cell death pathway, biochemically linking CED-9 and the Bcl-2 family to CED-3 and the ICE family of pro-apoptotic cysteine proteases.AD - University of Michigan Medical School, Department of Pathology, Ann Arbor, MI 48109, USA.FAU - Chinnaiyan, A MAU - Chinnaiyan AMFAU - O'Rourke, KAU - O'Rourke KFAU - Lane, B RAU - Lane BRFAU - Dixit, V MAU - Dixit VMLA - engID - 7863/PHSPT - Journal ArticleCY - UNITED STATESTA - ScienceJID - 0404511RN - 0 (Calcium-Binding Proteins)RN - 0 (Ced-4 protein)RN - 0 (Ced-9 protein)RN - 0 (Helminth Proteins)RN - 0 (Proto-Oncogene Proteins)RN - 0 (bcl-x protein)RN - EC 3.4.22 (Cysteine Endopeptidases)RN - EC 3.4.22.- (Ced-3 protein)RN - EC 3.4.22.- (caspase 8)RN - EC 3.4.22.36 (Caspase 1)SB - IM
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[
Sci Total Environ,
2022]
Ionic liquids (ILs) are difficult to degrade and even accumulate in the environment. Accordingly, their long-term toxicities are particularly important to demonstrate their accurate risk assessment. However, their long-term toxicities over generations and the toxicity mechanisms lacked thorough investigation. Presently, N-butylpyridinium bromide ([bpyr]Br), a representative IL, was chosen to measure its long-term effects on Caenorhabditis elegans for seven consecutive generations at 0.0225 and 22.5 mg/L. Toxicity mechanisms were explored in F1, F3, F5 and F7 by combining both antioxidant responses and lipid metabolism. Results showed that [bpyr]Br at low concentration provoked oscillatory effects on the reproduction over 7 generations, with inhibition in F1 and F7 and stimulation in F2, F4 and F5. At high concentration, [bpyr]Br showed similar multi-generational oscillation with greater inhibition in F1 and greater stimulation in F5. The effects of [bpyr]Br on the antioxidant responses to oxidative stress also showed oscillation over generations. The integrated biomarker response (IBR) values showed that [bpyr]Br at low concentration did not provoke significant influences on the overall antioxidant homeostasis in F1 and F3, but significantly stimulated it in F5 and F7. Meanwhile, [bpyr]Br at high concentration stimulated the antioxidant homeostasis in F1 and F7 with non-significant influences in F3 and F5. The IBR values regarding indicators in lipid metabolism showed that [bpyr]Br significantly and commonly stimulated the overall metabolism without concentration-dependent differences. Further analysis implied that [bpyr]Br provoked different mechanisms underlying the responses at low and high concentrations.
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[
J Med Microbiol,
2016]
Corynebacterium diphtheriae is typically recognized as a colonizer of the upper respiratory tract (respiratory diphtheria) and the skin (cutaneous diphtheria). However, different strains of Corynebacteriumdiphtheriae can also cause invasive infections. In this study, the characterization of a non-toxigenic Corynebacteriumdiphtheriae strain (designated BR-INCA5015) isolated from osteomyelitis in the frontal bone of a patient with adenoid cystic carcinoma was performed. Pathogenic properties of the strain BR-INCA5015 were tested in a Caenorhabditis elegans survival assay showing strong colonization and killing by this strain. Survival rates of 3.8+/-2.7%, 33.6+/-7.3% and 0% were observed for strains ATCC 27010T, ATCC 27012 and BR-INCA5015, respectively, at day 7. BR-INCA5015 was able to colonize epithelial cells, showing elevated capacity to adhere to and survive within HeLa cells compared to other Corynebacteriumdiphtheriae isolates. Intracellular survival in macrophages (THP-1 and RAW 264.7) was significantly higher compared to control strains ATCC 27010T (non-toxigenic) and ATCC 27012 (toxigenic). Furthermore, the ability of BR-INCA5015 to induce osteomyelitis was confirmed by in vivo assay using Swiss Webster mice.
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[
East Coast Worm Meeting,
1996]
During the earliest stages of embryogenesis in C. elegans, maternally-expressed SKN-1 protein directs cells to adopt fates that lead to formation of the pharynx, the gut, and part of the body-wall muscle. At the C-terminus of SKN-1 is a basic region (BR) like those of the basic-"leucine zipper" (bZIP) proteins. However, SKN-1 lacks a ZIP segment, which in bZIP proteins is essential for DNA binding because it mediates their dimerization, and may stabilize and orient the BR as an a-helix in the major groove. In contrast, SKN-1 binds to DNA as a monomer with nanomolar affinity, to a specific sequence consisting of a bZIP half-site adjacent to an AT-rich region. At the C-terminus of its 85 amino acid DNA-binding domain (the Skn domain) is its BR, and at the N-terminus is a sequence related to the flexible N-terminal "arm" (HD arm) with which homeodomain proteins bind to DNA in the minor groove. We have undertaken a series of mutagenesis, spectroscopic, and biochemical "footprinting" experiments to investigate how SKN-1 binds to DNA at high affinity as a monomer. Our findings indicate that the Skn domain inserts the BR into the major groove of the bZIP half-site, and places the HD arm in the minor groove of the AT-rich sequence. The intervening residues, which are distinct from homeodomains and ZIP segments, are both necessary and sufficient to promote sequence-specific DNA binding by the SKN-1 BR. When the Skn domain is not bound to DNA, the BR is unstructured, and the intervening residues are predominantly a-helical. However, surprisingly, this helical region is not rigidly ordered in structure, but exists in a partially-ordered state termed a "molten globule." Upon DNA binding, the BR forms an a-helix, the HD arm binds in the minor groove, and the intervening residues form a helical structure which is stably ordered, and which itself stabilizes the bound BR helix. Stabilization of the BR does not appear to involve intramolecular interactions with its side chains, but is impaired by disruption of residues in the helix immediately N-terminal to it. These findings demonstrate that the BR is not "trapped" in the major groove by side chain interactions, and indicate instead that its stability requires direct extension of a continuous a-helix from the adjacent helical structure. The SKN-1 DNA binding domain is thus unique in two respects: it represents the only known example of monomeric binding by a BR, and is the only such domain which is capable of sequence-specific binding but does not have at least some portion that is rigidly ordered when not bound to DNA. These results further imply that stability deriving from helix extension is likely an important factor in DNA binding by other BR-containing proteins.
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[
Environ Pollut,
2020]
Ionic liquids (ILs) are considered as extracting solvents in soil remediation. However, they can be pollutants themselves, and their own toxicities are of concerns. Notably, organisms were exposed to pollutants at random life stages in actual environmental exposure scenario, which is different from the set-up of one uniform life stage in usual experiment designs. The influence of life stages on ILs toxicities will provide essential information on their actual environmental risks. In the present study, effects of 1-ethyl-3-methylimidazolium bromide ([C<sub>2</sub>mim]Br) were measured on C.elegans with egg exposure and adult exposure. In egg exposure, [C<sub>2</sub>mim]Br increased the lifespan, stimulated initial reproduction and inhibited the total reproduction. Biochemical indices including oxidative stress, antioxidant responses and oxidative damage were further measured to explore the toxicity mechanisms. Results showed that [C<sub>2</sub>mim]Br significantly stimulated O<sub>2</sub><sup>-</sup>- as the oxidative stress and superoxide dismutase (SOD) as the antioxidant defense. In adult exposure, [C<sub>2</sub>mim]Br inhibited initial reproduction, total reproduction and lifespan. Biochemical results showed that [C<sub>2</sub>mim]Br significantly stimulated H<sub>2</sub>O<sub>2</sub> and oxidized glutathione (GSSG). The overall findings demonstrated that [C<sub>2</sub>mim]Br caused life stage-dependent toxicities on C.elegans. Future studies are still needed for the detailed mechanisms.
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[
Worm Breeder's Gazette,
1994]
More degenerins in the worm? Harbinder Singh Dhillon and Monica Driscoll. Department of Molecular Biology and Biochemistry, Rutgers University, Center for Advanced Biotechnology and Medicine, 679 Hoes lane, Piscataway, N.J. 08855
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Okazaki A, Sudo Y, Reissig L, Kamiya M, Sugo S, Takagi S, Yagasaki J, Hayashi S, Ono H, Inoue K, Kandori H, Ihara K
[
J Biol Chem,
2013]
Ion-transporting rhodopsins are widely utilized as optogenetic tools both for light-induced neural activation and silencing. The most studied representative is Bacteriorhodopsin (BR), which absorbs green/red light (570 nm) and functions as a proton pump. Upon photoexcitation, BR induces a hyperpolarization across the membrane, which, if incorporated into a nerve cell, results in its neural silencing. In this study, we show that several residues around the retinal chromophore, which are completely conserved among BR homologs from the archaea, are involved in the spectral tuning in a BR homolog (HwBR) and that the combination mutation causes a large spectral blue shift (max = 498 nm) while preserving the robust pumping activity. Quantum mechanics/molecular mechanics calculations revealed that, compared with the wild type, the -ionone ring of the chromophore in the mutant is rotated 130 because of the lack of steric hindrance between the methyl groups of the retinal and the mutated residues, resulting in the breakage of the conjugation system on the polyene chain of the retinal. By the same mutations, similar spectral blue shifts are also observed in another BR homolog, archearhodopsin-3 (also called Arch). The color variant of archearhodopsin-3 could be successfully expressed in the neural cells of Caenorhabditis elegans, and illumination with blue light (500 nm) led to the effective locomotory paralysis of the worms. Thus, we successfully produced a blue-shifted proton pump for neural silencing.
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[
Front Behav Neurosci,
2015]
In blast-related mild traumatic brain injury (br-mTBI) little is known about the connections between initial trauma and expression of individual clinical symptoms. Partly due to limitations of current in vitro and in vivo models of br-mTBI, reliable prediction of individual short- and long-term symptoms based on known blast input has not yet been possible. Here we demonstrate a dose-dependent effect of shock wave exposure on C. elegans using shock waves that share physical characteristics with those hypothesized to induce br-mTBI in humans. Increased exposure to shock waves resulted in decreased mean speed of movement while increasing the proportion of worms rendered paralyzed. Recovery of these two behavioral symptoms was observed during increasing post-traumatic waiting periods. Although effects were observed on a population-wide basis, large interindividual variability was present between organisms exposed to the same highly controlled conditions. Reduction of cavitation by exposing worms to shock waves in polyvinyl alcohol resulted in reduced effect, implicating primary blast effects as damaging components in shock wave induced trauma. Growing worms on NGM agar plates led to the same general results in initial shock wave effect in a standard medium, namely dose-dependence and high interindividual variability, as raising worms in liquid cultures. Taken together, these data indicate that reliable prediction of individual clinical symptoms based on known blast input as well as drawing conclusions on blast input from individual clinical symptoms is not feasible in br-mTBI.
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[
Worm Breeder's Gazette,
1992]
A Hot-spot for Mutations in a Cys-rich Domain of
mec-4 Includes a Site Which, When Mutated, Can Suppregg a Dominant Death inducing Mutation in Cis Kyonsoo Hong and Monica Driscoll. Department of Molecular Biology and Biochemistry, Rutgers University, Center for Advanced Biotechnology and Medicine, 679 Hoes Lane, Piscataway, N.J. 08855 (908) 463-5193
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[
Proc Natl Acad Sci U S A,
1973]
The nematode Caenorhabditis elegans is attracted by at least four classes of attractants: by cyclic nucleotides, cAMP and cGMP; by anions, Cl-, Br-, I-; by cations, Na+, Li+, K+, Mg+; and by alkaline pH values. The nematode's behavioral response to gradients of these attractants involves orientation and movement up the gradient, accumulation, and then habituation. Comparison of the tracks of wild-type and mutant animals responding to gradients of attractants indicates that sensory receptors in the head alone mediate the orientation response and that the direction of orientation is determined by the lateral motion of the head. Therefore, the orientation response is