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[
Food Funct,
2016]
Tsai Tai is one of the most widely consumed Brassica vegetables in Asian countries because of its good taste and its nutritional benefits. This study evaluated the antioxidant capacity and possible associated health benefits of 3 Tsai Tai (Brassica chinensis) varieties, namely, Hon Tsai Tai, Pak Choi and Choi Sum. The DPPH radical scavenging ability and reducing power assays were performed to evaluate the in vitro activities of the extracts. Caenorhabditis elegans was used as an in vivo model for evaluation of beneficial health effects, including antioxidant activity and delayed aging. In vitro, the Hon Tsai Tai extract exhibited higher antioxidant activities than Pak Choi and Choi Sum, and the total phenolic contents were significantly correlated with the DPPH and RP values. In vivo, the three assayed Tsai Tai extracts significantly increased resistance against paraquat-induced oxidative stress with an increase in survival rates from 15% to 28% compared with controls. However, only the extract from Hon Tsai Tai significantly prolonged the lifespan of Caenorhabditis elegans, with an 8% increase in the mean lifespan with respect to controls. Further evidence of antioxidant protection was obtained by assessing ROS production via the DCF assay. The analyses of intracellular SOD activity and MDA content confirmed the existence of an antioxidant protective effect. These results suggest that Tsai Tai might serve as a good source of natural antioxidants, and in particular, Hon Tsai Tai could be explored as a potential dietary supplement to retard aging.
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[
J Pharmacol Exp Ther,
2015]
NaCT (SLC13A5) is a Na(+)-coupled transporter for Krebs cycle intermediates and is expressed predominantly in the liver. Human NaCT is relatively specific for citrate compared with other Krebs cycle intermediates. The transport activity of human NaCT is stimulated by Li(+), whereas that of rat NaCT is inhibited by Li(+). We studied the influence of Li(+) on NaCTs cloned from eight different species. Li(+) stimulated the activity of only NaCTs from primates (human, chimpanzee, and monkey); by contrast, NaCTs from nonprimate species (mouse, rat, dog, and zebrafish) were inhibited by Li(+). Caenorhabditis elegans NaCT was not affected by Li(+). With human NaCT, the Li(+)-induced increase in transport activity was associated with the conversion of the transporter from a low-affinity/high-capacity type to a high-affinity/low-capacity type. H(+) was able to substitute for Li(+) in eliciting the stimulatory effect. The amino acid Phe500 in human NaCT was critical for Li(+)/H(+)-induced stimulation. Mutation of this amino acid to tryptophan (F500W) markedly increased the basal transport activity of human NaCT in the absence of Li(+), but the ability of Li(+) to stimulate the transporter was almost completely lost with this mutant. Substitution of Phe500 with tryptophan in human NaCT converted the transporter from a low-affinity/high-capacity type to a high-affinity/low-capacity type, an effect similar to that of Li(+) on the wild-type NaCT. These studies show that Li(+)-induced activation of NaCT is specific for the transporter in primates and that the region surrounding Phe500 in primate NaCTs is important for the Li(+) effect.
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[
J Appl Toxicol,
2015]
Lithium (Li) has been widely used to treat bipolar disorder, and industrial use of Li has been increasing; thus, environmental pollution and ecological impacts of Li have become a concern. This study was conducted to clarify the potential biological effects of LiCl and Li(2)CO(3) on a nematode, Caenorhabditis elegans as a model system for evaluating soil contaminated with Li. Exposure of C. elegans to LiCl and Li(2)CO(3) decreased growth/maturation and reproduction. The lowest observed effect concentrations for growth, maturation and reproduction were 1250, 313 and 10 000m, respectively, for LiCl and 750, 750 and 3000m, respectively, for Li(2)CO(3). We also investigated the physiological function of LiCl and LiCO(3) in C. elegans using DNA microarray analysis as an eco-toxicogenomic approach. Among approximately 300 unique genes, including metabolic genes, the exposure to 78m LiCl downregulated the expression of 36 cytochrome P450, 16 ABC transporter, 10 glutathione S-transferase, 16 lipid metabolism and two vitellogenin genes. On the other hand, exposure to 375m Li(2)CO(3) downregulated the expression of 11 cytochrome P450, 13 ABC transporter, 13 lipid metabolism and one vitellogenin genes. No gene was upregulated by LiCl or Li(2)CO(3). These results suggest that LiCl and Li(2)CO(3) potentially affect the biological and physiological function in C. elegans associated with alteration of the gene expression such as metabolic genes. Our data also provide experimental support for the utility of toxicogenomics by integrating gene expression profiling into a toxicological study of an environmentally important organism such as C. elegans.
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[
J Biol Chem,
2008]
Lithium (Li+) has been used to treat mood affect disorders, including bipolar, for decades (1;2). This drug is neuroprotective and has several identified molecular targets. However, it has a narrow therapeutic range and the underlying mechanism(s) of its therapeutic action is not understood. Here we describe a pharmacogenetic study of Li+ in the nematode Caenorhabditis elegans. Exposure to Li+ at clinically relevant concentrations throughout adulthood increases survival during normal aging (up to 46% median increase). Longevity is extended via a novel mechanism with altered expression of genes encoding nucleosome-associated functions. Li+ treatment results in reduced expression of the worm ortholog of LSD-1 (T08D10.2), a histone demethylase; knockdown by RNA interference (RNAi) of T08D10.2 is sufficient to extend longevity (~25% median increase), suggesting Li+ regulates survival by modulating histone methylation and chromatin structure.
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[
J Biol Chem,
2004]
Sodium-calcium exchangers have long been considered inert with respect to monovalent cations such as lithium, choline, and N-methyl-d-glucamine. A key question that has remained unsolved is how despite this, Li(+) catalyzes calcium exchange in mammalian tissues. Here we report that a Na(+)/Ca(2+) exchanger, NCLX cloned from human cells (known as FLJ22233), is distinct from both known forms of the exchanger, NCX and NCKX in structure and kinetics. Surprisingly, NCLX catalyzes active Li(+)/Ca(2+) exchange, thereby explaining the exchange of these ions in mammalian tissues. The NCLX protein, detected as both 70- and 55-KDa polypeptides, is highly expressed in rat pancreas, skeletal muscle, and stomach. We demonstrate, moreover, that NCLX is a K(+)-independent exchanger that catalyzes Ca(2+) flux at a rate comparable with NCX1 but without promoting Na(+)/Ba(2+) exchange. The activity of NCLX is strongly inhibited by zinc, although it does not transport this cation. NCLX activity is only partially inhibited by the NCX inhibitor, KB-R7943. Our results provide a cogent explanation for a fundamental question. How can Li(+) promote Ca(2+) exchange whereas the known exchangers are inert to Li(+) ions? Identification of this novel member of the Na(+)/Ca(2+) superfamily, with distinct characteristics, including the ability to transport Li(+), may provide an explanation for this phenomenon.
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[
J Cell Biol,
2024]
Rab GTPases function as intracellular molecular switches that regulate vesicular transport. In the current issue, Li et al. (https://doi.org/10.1083/jcb.202306107) revealed RAB-8 to RAB-11 transition governing the unconventional secretion of membrane proteins in the intestinal epithelium of C. elegans.
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[
Bull Soc Pathol Exot,
1997]
Several studies have been carried out on the transmission of Onchocerciasis by Simulium damnosum s.l. in the forest zone of Cote d'Ivoire. This study, carried out in 1979-1980 was devoted to determine the risk of onchocerciasis transmission inside and outside the rain forest of Tai (5 degrees 50' N-7 degrees 25' W). We present the vectorial capacity of S. sanctipauli in the region of Tai before massive flow of refugees from areas of Liberia without any control Programme. The results of micromorphological technics for determination of S. damnosum adults, showed that mainly females of S. sanctipauli were present. The studied populations had low parturity rates: 39.2% outside and 30.9% of parous flies inside the rain forest. The parasitic rates (0.4% of infectious females outside and 0.1% inside) and their parasitic loads (15 and 3 infective larvae per 1000 parous female respectively outside and inside the rain forest) were low, consequently their vectorial capacity with Onchocerca volvulus was almost non-existent in natural conditions. Before massive flow of refugees including persons carrying microfilariae, there were no problem of onchocerciasis within and outside the rain forest of Tai. However, the massive flow of refugees and the deforestation for growing crops can create situations favourable to the installation of more efficient vectors, increase man/vector contact and contribute to more intense onchocerciasis transmission. The monitoring of onchocerciasis transmission is necessary.
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[
STAR Protoc,
2022]
Live imaging is an important tool to track dynamic processes such as neuronal patterning events. Here, we describe a protocol for time-lapse microscopy analysis using neuronal migration and dendritic growth as examples. This protocol can provide detailed information for understanding cellular dynamics during postembryonic development in Caenorhabditis elegans (C. elegans). For complete details on the use and execution of this protocol, please refer to Feng etal. (2020), Li etal. (2021), and Wang etal. (2021).
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[
J Biol Chem,
1996]
Mutations of the degenerins (
deg-1,
mec-4,
mec-10) are the major known causes of hereditary neurodegeneration in the nematode Caenorhabditis elegans. We cloned a neuronal degenerin (MDEG) from human and rat brain. MDEG is an amiloride-sensitive cation channel permeable for Na+, K+, and Li+. This channel is activated by the same mutations which cause neurodegeneration in C. elegans. Like the hyperactive C. elegans degenerin mutants, constitutively active mutants of MDEG cause cell death, suggesting that gain of function of this novel neuronal ion channel might be involved in human forms of neurodegeneration.
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[
STAR Protoc,
2021]
Release of neurotransmitters by synaptic vesicle exocytosis at presynaptic terminals is critical for neuronal communication within the nervous system. Electrophysiology and electron microscopy are powerful and complementary approaches used to evaluate the function of synaptic proteins in synaptic transmission. Here, we provide a protocol detailing the use of these two approaches at C.elegans neuromuscular junctions, including steps for worm picking and dissection, in vivo electrophysiological recording, and sample preparation for electron microscopy, followed by imaging and analysis. For complete details on the use and execution of this protocol, please refer to Liu etal. (2021) and Li etal. (2021).