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1.
Peter Hechtman Bernard Boulay Marc De Braekeleer Eve Andermann Serge Melançon Jean Larochelle Claude Prevost Feige Kaplan 《Human genetics》1992,90(4):402-406
Mutations at the hexosaminidase A (HEXA) gene which cause Tay-Sachs disease (TSD) have elevated frequency in the Ashkenazi Jewish and French-Canadian populations. We report a novel TSD allele in the French-Canadian population associated with the infantile form of the disease. The mutation, a GA transition at the +1 position of intron 7, abolishes the donor splice site. Cultured human fibroblasts from a compound heterozygote for this transition (and for a deletion mutation) produce no detectable HEXA mRNA. The intron 7+1 mutation occurs in the base adjacent to the site of the adult-onset TSD mutation (G805A). In both mutations a restriction site for the endonuclease EcoRII is abolished. Unambiguous diagnosis, therefore, requires allele-specific oligonucleotide hybridization to distinguish between these two mutant alleles. The intron 7+1 mutation has been detected in three unrelated families. Obligate heterozygotes for the intron 7+1 mutation were born in the Saguenay-Lac-St-Jean region of Quebec. The most recent ancestors common to obligate carriers of this mutation were from the Charlevoix region of the province of Quebec. This mutation thus has a different geographic centre of diffusion and is probably less common than the exon 1 deletion TSD mutation in French Canadians. Neither mutation has been detected in France, the ancestral homeland of French Canada. 相似文献
2.
Scott L. Hooper Michael B. O'Neil Robert Wagner John Ewer Jorge Golowasch Eve Marder 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1986,159(2):227-240
Summary The muscles of the pyloric region of the stomach of the crab,Cancer borealis, are innervated by motorneurons found in the stomatogastric ganglion (STG). Electrophysiological recording and stimulating techniques were used to study the detailed pattern of innervation of the pyloric region muscles. Although there are two Pyloric Dilator (PD) motorneurons in lobsters, previous work reported four PD motorneurons in the crab STG (Dando et al. 1974; Hermann 1979a, b). We now find that only two of the crab PD neurons innervate muscles homologous to those innervated by the PD neurons in the lobster,Panulirus interrruptus. The remaining two PD neurons innervate muscles that are innervated by pyloric (PY) neurons inP. interruptus. The innervation patterns of the Lateral Pyloric (LP), Ventricular Dilator (VD), Inferior Cardiac (IC), and PY neurons were also determined and compared with those previously reported in lobsters. Responses of the muscles of the pyloric region to the neurotransmitters, acetylcholine (ACh) and glutamate, were determined by application of exogenous cholinergic agonists and glutamate. The effect of the cholinergic antagonist, curare, on the amplitude of the excitatory junctional potentials (EJPs) evoked by stimulation of the pyloric motor nerves was measured. These experiments suggest that the differences in innervation pattern of the pyloric muscles seen in crab and lobsters are also associated with a change in the neurotransmitter active on these muscles. Possible implications of these findings for phylogenetic relations of decapod crustaceans and for the evolution of neural circuits are discussed.Abbreviations
ACh
acetylcholine
-
Carb
carbamylcholine
-
cpv
muscles of the cardio-pyloric valve
-
cpv7n
nerve innervating muscle cpv7
-
cv
muscles of the ventral cardiac ossicles
-
cv1n
nerve innervating muscle cvl
-
cv2n
nerve innervating muscle cv2
-
EJP
excitatory junctional potential
-
IC
inferior cardiac neuron
-
IV
inferior ventricular neuron
-
IVN
inferior ventricular nerve
-
LP
lateral pyloric neuron
-
LPG
lateral posterior gastric neuron
-
lvn
lateral ventricular nerve
-
mvn
medial ventricular nerve
-
p
muscles of the pylorus
-
PD
pyloric dilator neuron
-
PD
in
intrinsic PD neuron
-
PD
ex
extrinsic PD neuron
-
pdn
pyloric dilator nerve
-
PY
pyloric neuron
-
pyn
pyloric nerve
-
STG
stomatogastric ganglion
-
VD
ventricular dilator neuron 相似文献
3.
Mechanisms for oscillation and frequency control in reciprocally inhibitory model neural networks 总被引:5,自引:0,他引:5
We describe four different mechanisms that lead to oscillations in a network of two reciprocally inhibitory cells. In two cases (intrinsic release and intrinsic escape) the frequency of the network oscillation is insensitive to the threshold voltage of the synaptic potentials. In the other two cases (synaptic release and synaptic escape) the network frequency is strongly determined by the threshold voltage of the synaptic connections. The distinction between the different mechanisms blurs as the function describing synaptic activation becomes less steep and as the model neurons are removed from the relaxation regime. These mechanisms provide insight into the parameters that control network frequency in motor systems that depend on reciprocal inhibition. 相似文献
4.
We investigate spike initiation and propagation in a model axon that has a slow regenerative conductance as well as the usual Hodgkin-Huxley type sodium and potassium conductances. We study the role of slow conductance in producing repetitive firing, compute the dispersion relation for an axon with an additional slow conductance, and show that under appropriate conditions such an axon can produce a traveling zone of secondary spike initiation. This study illustrates some of the complex dynamics shown by excitable membranes with fast and slow conductances. 相似文献
5.
6.
Ming Li Wang Lu Huang Deverie K. Bongard-Pierce Stephen Belmonte Eve Ann Zachgo John W. Morris Maureen Dolan Howard M. Goodman 《The Plant journal : for cell and molecular biology》1997,12(3):711-730
A method for construction of bacterial artificial chromosome (BAC) contigs from a yeast artifical chromosome (YAC) physical map is described. An ∼2 Mb contig, consisting of two large BAC contigs linked by a small YAC, has been assembled in the region around 80 cM of Arabidopsis thaliana chromosome 2. Clones from this contig will facilitate gene isolation in the region and can be used directly as substrates for DNA sequencing. 相似文献
7.
Martin Poe Joseph K. Wu Tsau-Yen Lin Karst Hoogsteen Herbert G. Bull Eve E. Slater 《Analytical biochemistry》1984,140(2):459-467
A synthetic tetradecapeptide, H-Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Val-Ile-His-Ser-OH, which corresponds to the 13 amino terminal residues of human angiotensinogen plus a carboxy terminal serine to replace a suggested site of carbohydrate attachment, has been shown to be a good substrate for human kidney renin. At pH 7.2 and 37 degrees C the KM or Michaelis constant was 8.4 +/- 2.9 microM, and the VM or velocity at infinite tetradecapeptide concentration was 11.3 +/- 2.4 mumol angiotensin I made per hour per milligram renin. The tetradecapeptide was highly resistant to cleavage by mouse submaxillary renin. The tetradecapeptide was also slowly cleaved by human liver cathepsin D, by rabbit lung angiotensin-converting enzyme, and by reconstituted human serum, but did not yield angiotensin I. Thus, this synthetic renin substrate should permit more specific measurement of human kidney renin activity. 相似文献
8.
9.
Peter J. Davies Eve Emshwiller Thomas J. Gianfagna William M. Proebsting Masana Noma Richard P. Pharis 《Planta》1982,154(3):266-272
The gibberellins (GAs) of both vegetative (leaves and stems) and reproductive (pods and seeds) tissue of the G2 strain of peas Pisum sativum L. were characterized in purified extracts by a combination of sequential silicic-acid partition column chromatography, and gas chromatography-mass spectrometry. Gibberellins A19, A20, A29 and an A29 catabolite were identified in both types of tissue. Gibberellins A9, A17 and A44 were also found in pods and seeds.Abbreviations FID
Ilame ionization detector
- GA(s)
gibberellin(s)
- GC
gas chromatograph(y)
- HPLC
high performance liquid chromatograph(y)
- LD
long day
- MS
mass spectrum(a) or mass spectrometer(ry)
- SD
short day 相似文献
10.
Isaac John Huiqing Wang Bruce M. Held Eve Syrkin Wurtele James T. Colbert 《Plant molecular biology》1992,20(5):821-831
A near full-length cDNA clone (pZRP3) corresponding to an mRNA that accumulates specifically in roots of maize was isolated. The ZRP3 mRNA is ca. 600 nucleotides in length. The amino acid sequence of the predicted polypeptide is rich in leucine (16%), proline (11%), and cysteine (8.5%). The zrp3 gene appears to be expressed exclusively in roots, whereas other ZRP3-related genes are expressed in additional organs of the maize plant. In situ hybridization shows that ZRP3 mRNA accumulation is largely confined to the cells of the cortical ground meristem. Furthermore, accumulation of this mRNA occurs within a distinct subset of cortical cells, the inner three to four cell layers.Journal paper number J-14572 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa Project Number 2997. 相似文献