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1.
Curr Biol ; 18(13): 1010-5, 2008 Jul 08.
Article in English | MEDLINE | ID: mdl-18583134

ABSTRACT

Learning and memory are essential processes of both vertebrate and invertebrate nervous systems that allow animals to survive and reproduce. The neurotransmitter glutamate signals via ionotropic glutamate receptors (iGluRs) that have been linked to learning and memory formation; however, the signaling pathways that contribute to these behaviors are still not well understood. We therefore undertook a genetic and electrophysiological analysis of learning and memory in the nematode Caenorhabditis elegans. Here, we show that two genes, nmr-1 and nmr-2, are predicted to encode the subunits of an NMDA-type (NMDAR) iGluR that is necessary for memory retention in C. elegans. We cloned nmr-2, generated a deletion mutation in the gene, and showed that like nmr-1, nmr-2 is required for in vivo NMDA-gated currents. Using an associative-learning paradigm that pairs starvation with the attractant NaCl, we also showed that the memory of a learned avoidance response is dependent on NMR-1 and NMR-2 and that expression of NMDARs in a single pair of interneurons is sufficient for normal memory. Our results provide new insights into the molecular and cellular mechanisms underlying the memory of a learned event.


Subject(s)
Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/metabolism , Memory , N-Methylaspartate/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Amino Acid Sequence , Animals , Appetitive Behavior/drug effects , Association Learning , Avoidance Learning , Caenorhabditis elegans/drug effects , Caenorhabditis elegans/genetics , Caenorhabditis elegans Proteins/genetics , Carrier Proteins/metabolism , Chemotaxis , Food , Interneurons/metabolism , Molecular Sequence Data , Mutation , Receptors, N-Methyl-D-Aspartate/genetics , Sequence Homology, Amino Acid , Sodium Chloride/pharmacology , Starvation
2.
J Gastroenterol ; 41(8): 802-6, 2006 Aug.
Article in English | MEDLINE | ID: mdl-16988771

ABSTRACT

BACKGROUND: Dynamic three-dimensional computed tomography (D-3DCT: high-speed helical scanning during defecation) was used for morphological evaluation of intrapelvic structures in patients with rectal prolapse and rectocele. METHODS: Twenty-five patients with rectal prolapse or rectocele diagnosed by conventional defecography (CD) or clinical findings were additionally investigated with D-3DCT. D-3DCT images were acquired using a multislice CT system with a 16-row detector during simulated defecation. Helical scanning was performed with a slice thickness of 1 mm, a helical pitch of 15 s/rotation, and a table movement speed of 35 mm/s. The contrast medium, 100 ml of iopamidol (370 mg/ml), was injected at a rate of 2.5 ml/s to enhance contrast with other structures, and scan start was triggered by using a function for automatically determining the optimal scan timing. RESULTS: Among the eight patients with rectocele, additional intrapelvic disorders were diagnosed in five (enterocele, 4; cystocele, 1; and uterine prolapse, 1) with D-3DCT. In the 17 patients with rectal prolapse, concomitant intrapelvic disorders were found in six (intussusception, 3; cystocele, 2; uterine prolapse, 2; rectocele, 1; and vaginal prolapse, 1). CONCLUSIONS: D-3DCT can be a useful diagnostic tool for investigation of pelvic pathology in patients with rectocele and rectal prolapse.


Subject(s)
Defecography , Pelvis/diagnostic imaging , Rectal Prolapse/diagnostic imaging , Rectocele/diagnostic imaging , Tomography, Spiral Computed , Adult , Aged , Aged, 80 and over , Cystocele/complications , Cystocele/diagnostic imaging , Female , Hernia/complications , Hernia/diagnostic imaging , Humans , Imaging, Three-Dimensional , Intussusception/complications , Intussusception/diagnostic imaging , Male , Middle Aged , Rectal Diseases/complications , Rectal Diseases/diagnostic imaging , Rectal Prolapse/complications , Rectocele/complications , Uterine Prolapse/complications , Uterine Prolapse/diagnostic imaging
3.
Exp Cell Res ; 287(2): 350-60, 2003 Jul 15.
Article in English | MEDLINE | ID: mdl-12837290

ABSTRACT

In Caenorhabditis elegans embryogenesis, phosphorylation events are critical to chromosomal changes. To investigate the dephosphorylation of chromosome behavior, we cloned and characterized the cDNA that encodes C. elegans protein phosphatase type 1 (CeGLC-7 beta), which is composed of 333 amino acids. CeGLC-7 beta possesses a highly conserved amino acid sequence with mammalian and Drosophila protein phosphatase 1. Here, we report on the contribution of CeGLC-7 beta to the dephosphorylation of histone H3 at anaphase. At the embryonic stage, CeGLC-7 beta is associated with the nuclear membrane and chromosomes. The deletion of the Ceglc-7 beta gene and a microinjection of double-stranded RNA produce a disorganized embryogenesis. The Ceglc-7 beta gene mutation causes an abnormal accumulation of phosphorylated histone H3 and delays the mitotic process after anaphase. We propose that CeGLC-7 beta is involved in chromosome dynamics including histone H3 dephosphorylation.


Subject(s)
Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/enzymology , Genes, Helminth , Phosphoprotein Phosphatases/metabolism , Amino Acid Sequence , Anaphase/genetics , Animals , Base Sequence , Caenorhabditis elegans/embryology , Caenorhabditis elegans/genetics , Caenorhabditis elegans Proteins/genetics , Conserved Sequence , Embryo, Nonmammalian/cytology , Embryo, Nonmammalian/metabolism , Gene Deletion , Gene Expression Regulation, Developmental , Green Fluorescent Proteins , Histones/metabolism , Luminescent Proteins/metabolism , Metaphase/genetics , Molecular Sequence Data , Phosphoprotein Phosphatases/genetics , Phosphorylation , Protein Phosphatase 1 , RNA, Double-Stranded/metabolism , RNA, Small Interfering/metabolism , Sequence Homology, Amino Acid
4.
J Neurogenet ; 16(1): 29-44, 2002.
Article in English | MEDLINE | ID: mdl-12420788

ABSTRACT

The acquisition and retention of information by the nervous system are major processes of learning. Habituation is a simple learning process that occurs during repeated exposure to harmless stimuli. C. elegans is habituated when repeatedly given mechanical stimuli and recover from the habituation when the stimuli are stopped. A habituation abnormal mutant was isolated and assigned to a new gene hab-1 whose mutation causes slow habituation. The hab-1 mutant phenotype is remarkable at short time interval stimuli. However, hab-1 mutant worms show normal dishabituation. Ablations of neurons constituting the neural circuit for mechanical reflexes did not abolish abnormalities caused by the hab-1 mutation.


Subject(s)
Caenorhabditis elegans/physiology , Habituation, Psychophysiologic/genetics , Mutation , Animals , Caenorhabditis elegans/genetics , Models, Neurological , Nerve Net/physiology , Neurons/physiology , Physical Stimulation/methods , Reflex/physiology , Touch
5.
FEBS Lett ; 516(1-3): 53-7, 2002 Apr 10.
Article in English | MEDLINE | ID: mdl-11959102

ABSTRACT

The Caenorhabditis elegans homolog of mortalin/mthsp70/Grp75 (called mot-2 hereafter) was isolated by screening of a nematode cDNA library with mouse mot-2 cDNA. The isolated clone matched to hsp70F of C. elegans. Analysis with two of the antibodies raised against hsp70F revealed that unlike mammalian mot-2, it is heat inducible. Transient induction of hsp70F by heat shock led to a slight (<13%) extension in the C. elegans life span. The transgenic worms that constitutively over-expressed hsp70F predominantly in muscle showed life span extension (approximately 43% for mean and approximately 45% for maximum life span) as compared to the wild-type and green fluorescent protein-transgenic worms. Life span extension of human cells was obtained by over-expression of mot-2 [Kaul et al. (2000) FEBS Lett. 474, 159-164]. Our results show, for the first time, that this member of the hsp70 family governs the longevity of worms and thus there are common pathways that determine mammalian and worm longevity.


Subject(s)
Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans/genetics , Genes, Helminth , HSP70 Heat-Shock Proteins/genetics , Longevity/genetics , Amino Acid Sequence , Animals , Animals, Genetically Modified , Caenorhabditis elegans/physiology , Caenorhabditis elegans Proteins/physiology , Gene Expression , HSP70 Heat-Shock Proteins/physiology , Hot Temperature , Humans , Membrane Proteins/genetics , Mice , Mitochondrial Proteins , Molecular Sequence Data , Sequence Homology, Amino Acid
6.
J Biol Chem ; 277(14): 12228-36, 2002 Apr 05.
Article in English | MEDLINE | ID: mdl-11796737

ABSTRACT

Remodeling of the extracellular matrix (ECM) is pivotal for various biological processes, including organ morphology and development. The Caenorhabditis elegans male tail has male-specific copulatory organs, the rays and the fan. Ray morphogenesis, which involves a rapid remodeling of the ECM, is an important model of morphogenesis, although its mechanism is poorly understood. ADAMTS (a disintegrin-like and metalloproteinase with thrombospondin type I motifs) is a novel metalloproteinase family that is thought to be an important regulator for ECM remodeling during development and pathological states. We report here that a new C. elegans ADAMTS family gene, adt-1, plays an important regulatory role in ray morphogenesis. Inactivation of the adt-1 gene resulted in morphological changes in the rays as well as the appearance of abnormal protuberances around the rays. In addition, mating ability was remarkably impaired in adt-1 deletion mutant males. Furthermore, we found that the green fluorescent protein reporter driven by the adt-1 promoter was specifically expressed throughout the rays in the male tail. We hypothesize that ADT-1 controls the ray extension process via remodeling of the ECM in the cuticle.


Subject(s)
Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/physiology , Caenorhabditis elegans/chemistry , Caenorhabditis elegans/genetics , Disintegrins/genetics , Genitalia, Male/physiology , Metalloendopeptidases/genetics , ADAM Proteins , ADAMTS1 Protein , Amino Acid Sequence , Animals , Animals, Genetically Modified , Base Sequence , Caenorhabditis elegans Proteins/biosynthesis , Cattle , Cosmids , Extracellular Matrix/metabolism , Gene Deletion , Genes, Reporter , Green Fluorescent Proteins , Humans , Luminescent Proteins/metabolism , Male , Mice , Models, Genetic , Molecular Sequence Data , Mutation , Phenotype , Physical Chromosome Mapping , Promoter Regions, Genetic , Protein Structure, Tertiary , Recombinant Fusion Proteins/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Sequence Homology, Amino Acid
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