Walker C

References (12)

Title : A Papaver somniferum 10-gene cluster for synthesis of the anticancer alkaloid noscapine - Winzer_2012_Science_336_1704
Author(s) : Winzer T , Gazda V , He Z , Kaminski F , Kern M , Larson TR , Li Y , Meade F , Teodor R , Vaistij FE , Walker C , Bowser TA , Graham IA
Ref : Science , 336 :1704 , 2012
Abstract : Noscapine is an antitumor alkaloid from opium poppy that binds tubulin, arrests metaphase, and induces apoptosis in dividing human cells. Elucidation of the biosynthetic pathway will enable improvement in the commercial production of noscapine and related bioactive molecules. Transcriptomic analysis revealed the exclusive expression of 10 genes encoding five distinct enzyme classes in a high noscapine-producing poppy variety, HN1. Analysis of an F(2) mapping population indicated that these genes are tightly linked in HN1, and bacterial artificial chromosome sequencing confirmed that they exist as a complex gene cluster for plant alkaloids. Virus-induced gene silencing resulted in accumulation of pathway intermediates, allowing gene function to be linked to noscapine synthesis and a novel biosynthetic pathway to be proposed.
ESTHER : Winzer_2012_Science_336_1704
PubMedSearch : Winzer_2012_Science_336_1704
PubMedID: 22653730
Gene_locus related to this paper: papso-cxe1

Title : Novel protein targets for organophosphorus compounds - Richards_1999_Chem.Biol.Interact_119-120_503
Author(s) : Richards P , Johnson M , Ray D , Walker C
Ref : Chemico-Biological Interactions , 119-120 :503 , 1999
Abstract : Inhibition of tritiated di-isopropyl phosphorofluoridate labelling by a range of organophopshorus compounds was used to screen for novel OP-reactive targets in rat-brain homogenates. Analysis of target proteins was conducted by SDS/PAGE and detection of tritiated proteins using a thin layer chromatography (TLC) linear analyser. Two major sites of 3H-DFP labelling were found with relative molecular masses of 30 and 85 kDa. Rates of reaction of these labelling sites with a range of OP compounds were compared to that of acetylcholinesterase. The 30 kDa band was found to be more sensitive to paraoxon, dichlorvos and diazoxon than acetylcholinesterase. The 85 kDa band was found to be more sensitive to dichlorvos and diazoxon than acetylcholinesterase. Neither labelling band reacted with chlorfenvinphos or demeton-s-methyl at significant rates.
ESTHER : Richards_1999_Chem.Biol.Interact_119-120_503
PubMedSearch : Richards_1999_Chem.Biol.Interact_119-120_503
PubMedID: 10421489

Title : The DNA sequence of human chromosome 22 - Dunham_1999_Nature_402_489
Author(s) : Dunham I , Hunt AR , Collins JE , Bruskiewich R , Beare DM , Clamp M , Smink LJ , Ainscough R , Almeida JP , Babbage AK , Bagguley C , Bailey J , Barlow KF , Bates KN , Beasley OP , Bird CP , Blakey SE , Bridgeman AM , Buck D , Burgess J , Burrill WD , Burton J , Carder C , Carter NP , Chen Y , Clark G , Clegg SM , Cobley VE , Cole CG , Collier RE , Connor R , Conroy D , Corby NR , Coville GJ , Cox AV , Davis J , Dawson E , Dhami PD , Dockree C , Dodsworth SJ , Durbin RM , Ellington AG , Evans KL , Fey JM , Fleming K , French L , Garner AA , Gilbert JGR , Goward ME , Grafham DV , Griffiths MND , Hall C , Hall RE , Hall-Tamlyn G , Heathcott RW , Ho S , Holmes S , Hunt SE , Jones MC , Kershaw J , Kimberley AM , King A , Laird GK , Langford CF , Leversha MA , Lloyd C , Lloyd DM , Martyn ID , Mashreghi-Mohammadi M , Matthews LH , Mccann OT , Mcclay J , Mclaren S , McMurray AA , Milne SA , Mortimore BJ , Odell CN , Pavitt R , Pearce AV , Pearson D , Phillimore BJCT , Phillips SH , Plumb RW , Ramsay H , Ramsey Y , Rogers L , Ross MT , Scott CE , Sehra HK , Skuce CD , Smalley S , Smith ML , Soderlund C , Spragon L , Steward CA , Sulston JE , Swann RM , Vaudin M , Wall M , Wallis JM , Whiteley MN , Willey DL , Williams L , Williams SA , Williamson H , Wilmer TE , Wilming L , Wright CL , Hubbard T , Bentley DR , Beck S , Rogers J , Shimizu N , Minoshima S , Kawasaki K , Sasaki T , Asakawa S , Kudoh J , Shintani A , Shibuya K , Yoshizaki Y , Aoki N , Mitsuyama S , Roe BA , Chen F , Chu L , Crabtree J , Deschamps S , Do A , Do T , Dorman A , Fang F , Fu Y , Hu P , Hua A , Kenton S , Lai H , Lao HI , Lewis J , Lewis S , Lin S-P , Loh P , Malaj E , Nguyen T , Pan H , Phan S , Qi S , Qian Y , Ray L , Ren Q , Shaull S , Sloan D , Song L , Wang Q , Wang Y , Wang Z , White J , Willingham D , Wu H , Yao Z , Zhan M , Zhang G , Chissoe S , Murray J , Miller N , Minx P , Fulton R , Johnson D , Bemis G , Bentley D , Bradshaw H , Bourne S , Cordes M , Du Z , Fulton L , Goela D , Graves T , Hawkins J , Hinds K , Kemp K , Latreille P , Layman D , Ozersky P , Rohlfing T , Scheet P , Walker C , Wamsley A , Wohldmann P , Pepin K , Nelson J , Korf I , Bedell JA , Hillier L , Mardis E , Waterston R , Wilson R , Emanuel BS , Shaikh T , Kurahashi H , Saitta S , Budarf ML , McDermid HE , Johnson A , Wong ACC , Morrow BE , Edelmann L , Kim UJ , Shizuya H , Simon MI , Dumanski JP , Peyrard M , Kedra D , Seroussi E , Fransson I , Tapia I , Bruder CE , O'Brien KP
Ref : Nature , 402 :489 , 1999
Abstract : Knowledge of the complete genomic DNA sequence of an organism allows a systematic approach to defining its genetic components. The genomic sequence provides access to the complete structures of all genes, including those without known function, their control elements, and, by inference, the proteins they encode, as well as all other biologically important sequences. Furthermore, the sequence is a rich and permanent source of information for the design of further biological studies of the organism and for the study of evolution through cross-species sequence comparison. The power of this approach has been amply demonstrated by the determination of the sequences of a number of microbial and model organisms. The next step is to obtain the complete sequence of the entire human genome. Here we report the sequence of the euchromatic part of human chromosome 22. The sequence obtained consists of 12 contiguous segments spanning 33.4 megabases, contains at least 545 genes and 134 pseudogenes, and provides the first view of the complex chromosomal landscapes that will be found in the rest of the genome.
ESTHER : Dunham_1999_Nature_402_489
PubMedSearch : Dunham_1999_Nature_402_489
PubMedID: 10591208
Gene_locus related to this paper: human-CES5A , human-SERHL2

Title : Identification of selected gamma-ray induced deficiencies in zebrafish using multiplex polymerase chain reaction - Fritz_1996_Genetics_144_1735
Author(s) : Fritz A , Rozowski M , Walker C , Westerfield M
Ref : Genetics , 144 :1735 , 1996
Abstract : The ease with which mutations can be generated in zebrafish makes this vertebrate an important resource for developmental genetics and genome studies. We have developed a PCR-based screening method that allows the efficient identification of gamma-ray induced deficiencies targeted to selected sequences. We describe three mutants characteristic of our findings and show that these mutations include deletions and translocations that can affect as much as 1% of the genome. These deficiencies provide a basis for analyzing the functions of cloned zebrafish genes using noncomplementation screens for point mutations induced by high-efficiency chemical mutagenesis.
ESTHER : Fritz_1996_Genetics_144_1735
PubMedSearch : Fritz_1996_Genetics_144_1735
PubMedID: 8978059

Title : Induction of muscle pioneers and floor plate is distinguished by the zebrafish no tail mutation - Halpern_1993_Cell_75_99
Author(s) : Halpern ME , Ho RK , Walker C , Kimmel CB
Ref : Cell , 75 :99 , 1993
Abstract : Dorsal mesoderm is thought to provide important signals for axis formation and neural differentiation in vertebrate embryos. We have examined induction and patterning in a zebrafish mutant, no tail, that lacks a derivative of dorsal mesoderm, the notochord. Despite the absence of a differentiated notochord, development of the central nervous system including floor plate appears normal, likely owing to the presence of notochord precursor cells. In contrast, somites are misshapen, and muscle pioneer cells are absent. Wild-type cells transplanted into mutant hosts can autonomously differentiate into notochord and thereby rescue somitic defects, suggesting that interactions between notochord and paraxial mesoderm are necessary for proper somite patterning. Thus, cells derived from dorsal mesoderm may have multiple signaling functions during zebrafish embryogenesis.
ESTHER : Halpern_1993_Cell_75_99
PubMedSearch : Halpern_1993_Cell_75_99
PubMedID: 8402905

Title : Cholinesterase and self-reported pesticide exposure among pregnant women - De Peyster_1993_Arch.Environ.Health_48_348
Author(s) : De Peyster A , Willis WO , Molgaard CA , MacKendrick TM , Walker C
Ref : Archives of Environmental Health , 48 :348 , 1993
Abstract : Ascertainment of exposure to cholinesterase-inhibiting pesticides in pregnant subjects is complicated by altered enzyme activity that results from metabolic changes associated with pregnancy. Nevertheless, this study found a high correlation (Pearson chi-square = 13.67, p = .008) between classification of pesticide exposure using self-reported interview information and plasma cholinesterase activity for 203 pregnant women for whom three trimester cholinesterase values were available. All plasma cholinesterase activity values were referenced, by trimester, to a larger sample of 1,050 plasma cholinesterase values from 535 pregnant women. Subjects who lived nearest to agricultural land and who reported that they worked with pesticides in agricultural and other occupations tended to have lower plasma cholinesterase activity than those who reported use of household pesticides only.
ESTHER : De Peyster_1993_Arch.Environ.Health_48_348
PubMedSearch : De Peyster_1993_Arch.Environ.Health_48_348
PubMedID: 8215600

Title : Pregnancy outcome among women exposed to pesticides through work or residence in an agricultural area - Willis_1993_J.Occup.Med_35_943
Author(s) : Willis WO , De Peyster A , Molgaard CA , Walker C , MacKendrick T
Ref : Journal of Occupational Medicine , 35 :943 , 1993
Abstract : The study population consisted of women enrolled in a southern California community clinic perinatal program. All women entering the program between January 1987 and December 1989 were asked to participate, and a cohort of 535 women was included in the study. Primarily Hispanic, of low income and educational level, many had recently immigrated from Mexico. They were potentially exposed to pesticides and other agricultural chemicals occupationally and/or environmentally because agricultural production in San Diego County is among the highest in the state. Study methods consisted of biologic assay of maternal blood samples for determination of cholinesterase activity and concurrent patient interviews to determine exposure history by self report. These assessments were conducted on each participant approximately once each trimester. Self-report and blood assay data were analyzed using chi 2, the Mantel-Haenszel extension of chi 2, and risk ratios to determine the association between pesticide exposure and spontaneous abortion, preterm birth, low birth weight and toxemia. No difference between exposed and unexposed women was noted for risk of preterm birth or toxemia. Subjects who experienced spontaneous abortion were all unexposed, and the rate of spontaneous abortion was 2.1%, less than generally expected. A greater incidence of low birth weight among unexposed women indicates that exposure may have had a "protective" effect.
ESTHER : Willis_1993_J.Occup.Med_35_943
PubMedSearch : Willis_1993_J.Occup.Med_35_943
PubMedID: 8229348

Title : Pathfinding and synapse formation in a zebrafish mutant lacking functional acetylcholine receptors - Westerfield_1990_Neuron_4_867
Author(s) : Westerfield M , Liu DW , Kimmel CB , Walker C
Ref : Neuron , 4 :867 , 1990
Abstract : We induced and characterized a recessive lethal mutation, nic-1, in zebrafish that blocks the function of muscle acetylcholine (ACh) receptors. Homozygous nic-1 embryos are nonmotile and fail to respond to exogenous application of cholinergic agonists, although their muscles contract in response to direct electrical stimulation. Moreover, we do not detect cell surface labeling by alpha-bungarotoxin or monoclonal antibodies that recognize the other three subunits of ACh receptors. Motoneurons, however, establish morphologically normal patterns of innervation and normal neuromuscular junctions. We suggest that neither transmitter-mediated nerve signaling nor any other aspect of ACh receptor function is required for the formation of appropriate nerve connections in this system.
ESTHER : Westerfield_1990_Neuron_4_867
PubMedSearch : Westerfield_1990_Neuron_4_867
PubMedID: 2361010

Title : Mutations affecting skeletal muscle myofibril structure in the zebrafish - Felsenfeld_1990_Development_108_443
Author(s) : Felsenfeld AL , Walker C , Westerfield M , Kimmel C , Streisinger G
Ref : Development , 108 :443 , 1990
Abstract : We describe embryonic lethal mutations in the zebrafish, Brachydanio rerio, which affect organization of skeletal muscle myofibrils. The mutations, fub-1(b45) and fub-1(b126), were independently isolated from progeny of gamma-irradiated females. Each segregates as a single recessive gene: b45 is located about 23 map units from its centromere. The b126 mutation has a similar but slightly larger apparent gene-centromere distance and a less severe phenotype. The two mutations fail to complement, suggesting that they are allelic. Homozygous b45 mutant embryos are paralyzed, and their axial skeletal muscle cells are unstriated, containing severely disorganized myofibrillar components. Gel-electrophoretic comparisons of b45 mutant and wild-type muscle proteins failed to reveal absent or altered major myofibrillar proteins. Embryos genetically mosaic for b45 were also phenotypically mosaic, suggesting that the defect is cell-autonomous. We suggest that these mutations identify a gene required for proper organization of skeletal muscle myofibrils, and that the more severe mutation may represent a null allele.
ESTHER : Felsenfeld_1990_Development_108_443
PubMedSearch : Felsenfeld_1990_Development_108_443
PubMedID: 2340809

Title : A neural degeneration mutation that spares primary neurons in the zebrafish - Grunwald_1988_Dev.Biol_126_115
Author(s) : Grunwald DJ , Kimmel CB , Westerfield M , Walker C , Streisinger G
Ref : Developmental Biology , 126 :115 , 1988
Abstract : We describe an embryonic lethal mutation in the zebrafish Brachydanio rerio that specifically affects the viability of most cells in the embryonic central nervous system (CNS). The mutation ned-1 (b39rl) was induced with gamma-irradiation and segregates as a single recessive allele closely linked to its centromere. It produces massive cell death in the CNS but a small set of specific neurons, including Rohon-Beard sensory neurons, large hindbrain interneurons, and primary motoneurons, survive embryogenesis and are functional. Synaptic connections between embryonic motoneurons and muscle cells appear physiologically normal, and the normally observed spontaneous flexions are present. Correlated with the presence of sensory neurons and interneurons, mutant embryos display reflexive movements in response to mechanical stimulation. Together, the surviving neurons, called primary neurons, form a class of cells that are prominent in size and arise early during development. Thus, this mutation may define a function that is differentially required by developmentally distinguishable sets of cells in the embryonic CNS.
ESTHER : Grunwald_1988_Dev.Biol_126_115
PubMedSearch : Grunwald_1988_Dev.Biol_126_115
PubMedID: 3342929

Title : Induction of mutations by gamma-rays in pregonial germ cells of zebrafish embryos -
Author(s) : Walker C , Streisinger G
Ref : Genetics , 103 :125 , 1983

Title : Production of clones of homozygous diploid zebra fish (Brachydanio rerio) - Streisinger_1981_Nature_291_293
Author(s) : Streisinger G , Walker C , Dower N , Knauber D , Singer F
Ref : Nature , 291 :293 , 1981
Abstract : Homozygous diploid zebra fish have been produced on a large scale by the application of simple physical treatments. Clones of homozygous fish have been produced from individual homozygotes. These clones and associated genetic methods will facilitate genetic analyses of this vertebrate.
ESTHER : Streisinger_1981_Nature_291_293
PubMedSearch : Streisinger_1981_Nature_291_293
PubMedID: 7248006