9 Papers found (0.009 seconds)

Kreppel LK et al. (1997) J Biol Chem "Dynamic glycosylation of nuclear and cytosolic proteins. Cloning and characterization of a unique O-GlcNAc transferase with multiple tetratricopeptide repeats."

Hart GW, Kreppel LK, Blomberg MA

[

J Biol Chem,

1997]

O-Linked N-acetylglucosamine (O-GlcNAc) glycosylation is a dynamic modification of eukaryotic nuclear and cytosolic proteins analogous to protein phosphorylation. We have cloned and characterized a novel gene for an O-GlcNAc transferase (OGT) that shares no sequence homology or structural similarities with other glycosyltransferases. The OGT gene is highly conserved (up to 80% identity) in all eukaryotes examined. Unlike previously described glycosyltransferases, OGT is localized to the cytosol and nucleus. The OGT protein contains multiple tandem repeats of the tetratricopeptide repeat motif. The presence of tetratricopeptide repeats, which can mediate protein-protein interactions, suggests that OGT may be regulated by protein interactions that are independent of the enzyme's catalytic site. The OGT is also modified by tyrosine phosphorylation, indicating that tyrosine kinase signal transduction cascades may play a role in modulating OGT activity.

Yokoyama I et al. (2023) Food Sci Nutr "Effects of the dipeptides comprising leucine and lysine on lifespan and age-related stress in Caenorhabditis elegans."

Nagasao J, Fujita N, Arihara K, Jia Y, Komiya Y, Yokoyama I, Setoyama O, Waki A

[

Food Sci Nutr,

2023]

The aging process is affected by various stressors. An increase in oxidative stress is related to the impairment of physiological functions and enhancement of glycative stress. Food-derived bioactive peptides have various physiological functions, including antioxidant activities. Dipeptides comprising Leu and Lys (LK and KL, respectively) have been isolated from foods; however, their physiological properties remain unclear. In this study, we investigated the antioxidant/antiglycation activity of dipeptides and their antiaging effects using Caenorhabditis elegans (C. elegans). Both dipeptides showed antioxidant activities against several reactive oxygen species (ROS) in vitro. In particular, the scavenging activity of LK against superoxide radicals was higher than KL did. Moreover, dipeptides suppressed advanced glycation end products (AGEs) formation in the BSA-glucose model. In the lifespan assays using wild-type C. elegans, both LK and KL significantly prolonged the mean lifespan by 20.9% and 11.7%, respectively. In addition, LK decreased intracellular ROS and superoxide radical levels in C. elegans. Blue autofluorescence, an indicator of glycation in C. elegans with age, was also suppressed by LK. These results suggest that dipeptides, notably LK, show an antiaging effect by suppressing oxidative and glycative stress. Our findings suggest that such dipeptides can be used as a novel functional food ingredient. Food-derived dipeptide Leu-Lys (LK) and Lys-Leu (KL) exert antioxidant and antiglycation activity in vitro. Treatment with LK prolonged the mean lifespan and maximum lifespan of C. elegans more than that of KL. Intracellular ROS and blue autofluorescence levels (indicator of aging) were suppressed by LK.

Smart D et al. (1993) Comp Biochem Physiol C "Use of specific antisera for the localisation and quantitation of leucokinin immunoreactivity in the nematode, Ascaris suum."

Shaw C, Johnston CF, Buchanan KD, Smart D, Halton DW

[

Comp Biochem Physiol C,

1993]

1. The leucokinins (LKs) are a group of eight related peptides isolated from the cockroach, Leucophaea maderae. 2. Antisera raised against LK-V, which were specific for the conserved mid to C-terminal region of the LKs, were used to immunostain the parasitic nematode Ascaris suum. 3. LK-IR was observed in neurons in the anterior nerve ring, retrovesicular ganglion, and ventral and dorsal nerve cords of the parasite. Immunostaining was specific in that it was abolished by preabsorption of the antiserum with different leucokinins. Some of the LK-immunoreactive neurons were identified on the basis of their morphological similarity with identified neurons in the free-living nematode Caenorhabditis elegans. 4. Immunoreactivity towards a number of other peptides, notably neuropeptide F, FMRF-amide, KGQELE and KELTAE, has previously been demonstrated in all LK-immunoreactive neurons, thus confirming the multiple-peptidergic nature of certain nematode nerves. 5. LK-IR was demonstrated and quantified in a number of tissues using RIA. Highest amounts were found in extracts of gut; LK-IR was also demonstrated in extracts of body wall, heads and tails, testes, ovaries and pseudocoelomic fluid. 6. The distribution of tissue LK-IR did not correlate with the amount of neuronal tissue in the samples. 7. Dilution experiments suggested that the LK-IR in the parasite is heterogeneous and that the peptide(s) in some tissues may not be analogous to the insect LKs. 8. The LK-IR in the parasite remains to be characterized; however, the results suggest that peptides related to the leucokinins may have a far wider phylogenetic distribution than has hitherto been thought.

Hubbard C et al. (2013) J Neurosci Res "Lanthionine ketimine ethyl ester partially rescues neurodevelopmental defects in unc-33 (DPYSL2/CRMP2) mutants."

Hubbard C, Holgado AM, O'Brien S, St John E, Benda E, Baxter T, Hardin T, Hensley K

[

J Neurosci Res,

2013]

Lanthionine ketimine (LK) is a natural sulfur amino acid metabolite with potent neurotrophic activity. Proteomics indicate that LK interacts with collapsin response mediator protein-2 (CRMP2/DPYSL2/UNC-33), a brain-enriched protein that was shown to regulate cytoskeletal remodeling, neuronal morphology, and synaptic function. To elucidate further the molecular interplay and biological action of LK and UNC-33, we began examining the nervous system of Caenorhabditis elegans nematodes in which both LK concentrations and UNC-33 protein were manipulated. To this end, a cell-permeable LK-ester (LKE) was administered to developing C. elegans engineered to express yellow fluorescent protein (YFP) in cholinergic neurons (strain RM3128) or green fluorescent protein (GFP) in GABAergic neurons (strain CZ1200), and neural morphology was assessed. Fluorescent imaging analyses show that LKE exposure to wild-type animals induced neural commissure outgrowth, crossing over, and bundling in both neurites from GABAergic and cholinergic motor neurons. Additionally, when unc-33(e204) hypomorph mutant nematodes (D389N substitution mutants) were exposed to LKE, both the neuroanatomical defects of incomplete dorsoventral neural commissures and the ventral nerve cord gaps were partially rescued. In contrast, LKE did not rescue ventral nerve cord gaps found in unc-33(mn407) null mutant. Together these data suggest possible functions for LK as a regulator of neuritic elongation, corroborate roles for UNC-33/CRMP2 in the mechanism of LKE activity, and suggest the potential of LKE as a therapeutic molecule for neurological diseases involving CRMP2 dysfunction.

Takeuchi S et al. (2024) Biosci Microbiota Food Health "Lactococcus kimchii extends lifespan and alleviates motility decline in Caenorhabditis elegans through ins-20, an insulin-like peptide gene."

Takeuchi S, Ali MS, Kage-Nakadai E, Tanimoto Y

[

Biosci Microbiota Food Health,

2024]

Lactococcus kimchii is isolated from commercial kimchi, which is a traditional Korean fermented food. This study was conducted to evaluate the probiotic effects of L. kimchii. Caenorhabditis elegans was fed L. kimchii, and its longevity, motility, and gene expression were examined. When fed a 1:1 mixture of Escherichia coli OP50 and L. kimchii (OP+LK), C. elegans had a significantly longer lifespan and increased locomotion than when it was fed OP alone. There was no significant difference in brood size between the OP+LK and OP groups, suggesting that these effects occurred in a dietary restriction-independent manner. RNA sequencing and Gene Ontology analysis showed that the expression of ins-20, an insulin-like peptide and agonist of the insulin receptor, was significantly upregulated in the OP+LK group. The ins-20 mutation annulled the effects of OP+LK on lifespan extension and motility. In addition, OP+LK failed to extend the lifespan of C. elegans deficient in daf-2, a receptor for the insulin-like signaling pathway. These results suggest that L. kimchii extends the lifespan and alleviates motility decline in C. elegans through the insulin signaling pathway, highlighting the potential of using L. kimchii as a beneficial bacterium for probiotics and postbiotics.

Hart GW et al. (1995) Adv Exp Med Biol "O-linked N-acetylglucosamine: the "yin-yang" of Ser/Thr phosphorylation? Nuclear and cytoplasmic glycosylation."

Cole RN, Snow DM, Greis KD, Jiang MS, Kreppel LK, Roquemore EP, Dong LY, Hart GW, Chou TY, Blomberg MA

[

Adv Exp Med Biol,

1995]

Chelo IM (2014) Nat Protoc "Experimental determination of invasive fitness in Caenorhabditis elegans."

Chelo IM

[

Nat Protoc,

2014]

Estimation of fitness is a key step in experimental evolution studies. However, no established methods currently exist to specifically estimate how successful new alleles are in invading populations. The main reason is that most assays do not accurately reflect the randomness associated with the first stages of the invasion, when invaders are rare and extinctions are frequent. In this protocol, I describe how such experiments can be done in an effective way. By using the nematode model, Caenorhabditis elegans, a large number of invasion experiments are set up, whereby invading individuals carrying a visual marker are introduced into populations in very low numbers. The number of invaders counted in consecutive generations, together with the number of extinctions, is then used in the context of individual-based computer simulations to provide likelihood (Lk) estimates for fitness. This protocol can take up to five generations of experimental invasions and a few hours of computer processing time.

Kushwaha VS et al. (2020) PLoS One "The crowding dynamics of the motor protein kinesin-II."

Denisov DV, Acar S, Peterman EJG, Kushwaha VS, Schall P, Miedema DM

[

PLoS One,

2020]

Intraflagellar transport (IFT) in C. elegans chemosensory cilia is an example of functional coordination and cooperation of two motor proteins with distinct motility properties operating together in large groups to transport cargoes: a fast and processive homodimeric kinesin-2, OSM-3, and a slow and less processive heterotrimeric kinesin-2, kinesin-II. To study the mechanism of the collective dynamics of kinesin-II of C. elegans cilia in an in vitro system, we used Total Internal Reflection Fluorescence microscopy to image the motility of truncated, heterodimeric kinesin-II constructs at high motor densities. Using an analysis technique based on correlation of the fluorescence intensities, we extracted quantitative motor parameters, such as motor density, velocity and average run length, from the image. Our experiments and analyses show that kinesin-II motility parameters are far less affected by (self) crowding than OSM-3. Our observations are supported by numerical calculations based on the TASEP-LK model (Totally Asymmetric Simple Exclusion Process-Langmuir Kinetics). From a comparison of data and modelling of OSM-3 and kinesin-II, a general picture emerges of the collective dynamics of the kinesin motors driving IFT in C. elegans chemosensory cilia and the way the motors deal with crowding.

Elizabeth X Kwan et al. (2004) West Coast Worm Meeting "Discovering glo-2: Identification of a gene necessary for lysosome biogenesis"

Elizabeth X Kwan, Greg J Hermann, Beverley M Rabbitts, Lena K Schroeder, James R Priess

[

West Coast Worm Meeting,

2004]

We are interested in identifying genes necessary for lysosome biogenesis in metazoans. Lysosomes are ubiquitous acidic organelles that act as terminal endocytic compartments and main sites of macromolecule degradation. Lysosomes in multicellular animals can play additional roles in plasma membrane repair, immune response, and pigmentation. In Drosophila and mammalian systems, many genes involved in pigmentation are required for proper lysosome biogenesis. Studies in these systems have led to the discovery of many metazoan restricted genes that function in the assembly of stable lysosomes. We are taking a genetic approach to identify genes necessary for lysosome biogenesis in C. elegans intestinal cells. Unlike other lysosomes in C. elegans, intestinal lysosomes contain birefringent contents. We have isolated over 100 mutants defective in lysosome biogenesis. These mutants, which define at least 3 distinct genes ( glo-1,-2,-3 ), all mislocalize birefringent lysosomal contents during embryonic development. We are focusing on characterizing the phenotype of the glo-2 mutant and identifying the glo-2 gene (for description of glo-1 see abstract by Schroeder, LK et al. ). glo-2 is defined by a single mutant allele, zu455, which has a maternal effect lysosome biogenesis defect. Adult glo-2 mutants lack acidic and terminal endocytic compartments in their intestinal cells. We are in the process of identifying the gene responsible for the loss of normal lysosome biogenesis in glo-2 mutants. Using snip-SNP analysis with the CB4856 strain, we have narrowed down the location of the glo-2 gene to a 0.4 map-unit region of chromosome I. We are currently performing cosmid rescue experiments to identify glo-2 .