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61.
Russell G. Snell Leslie M. Thompson Danilo A. Tagle Tracey L. Holloway Glenn Barnes Helen G. Harley Lodewijk A. Sandkuijl Marcy E. MacDonald Francis S. Collins James F. Gusella Peter S. Harper Duncan J. Shaw 《American journal of human genetics》1992,51(2):357-362
We report both a recombination event that places the Huntington disease gene proximal to the marker D4S98 and an extended linkage-disequilibrium study that uses this marker and confirms the existence of disequilibrium between it and the HD locus. We also report the cloning of other sequences in the region around D4S98, including a new polymorphic marker R10 and conserved sequences that identify a gene in the region of interest. 相似文献
62.
D L Maxwell R W Fuller C M Dixon F M Cuss P J Barnes 《Journal of applied physiology》1990,68(1):295-301
Animal studies suggest that the neuropeptides, substance P and vasoactive intestinal peptide (VIP), may influence carotid body chemoreceptor activity and that substance P may take part in the carotid body response to hypoxia. The effects of these peptides on resting ventilation and on ventilatory responses to hypoxia and to hypercapnia have been investigated in six normal humans. Infusions of substance P (1 pmol.kg-1.min-1) and of VIP (6 pmol.kg-1.min-1) were compared with placebo and with nitroprusside (5 micrograms.kg-1.min-1) as a control for the hypotensive action of the peptides. Both peptides caused significantly less hypotension than nitroprusside. Substance P and nitroprusside caused significantly greater increases in ventilation and in the hypoxic ventilatory response than VIP. No changes were seen in hypercapnic sensitivity. The stimulation of ventilation and the differential effects on ventilatory chemosensitivity that accompanied hypotension are consistent either with stimulation of carotid body chemoreceptor activity or with an interaction with peripheral chemoreceptor input to the respiratory center, as is seen in animals. The similar cardiovascular but different ventilatory effects of the peptides suggest that substance P may also stimulate the carotid body in a manner independent of the effect of hypotension. This is consistent with a role of substance P in the hypoxic ventilatory response in humans. 相似文献
63.
Six naturally occurring but rare alleles of sn-glycerol-3-phosphate dehydrogenase (Gpdh) in Drosophila melanogaster have been investigated in this study. They all belong to a class of Gpdh
UF
(ultra-fast) alleles, because their electrophoretic mobilities are faster than that of the Gpdh
F
(fast) allele. The Gpdh
UF
variants are widespread, and have been reported from five continents. DNA sequence analysis has shown that the change in electrophoretic mobility was in each allele caused by a single amino acid residue substitution in the encoded protein. In the Xiamen
UF
allele it is a substitution of lysine (AAA) to asparagine (AAT) in exon 1 (residue 3). An asparagine (AAT) to aspartate (GAT) change was found in exon 6 (residue 336) in the Iowa
UF
and Netherlands
UF
alleles. The mobility of the Raleigh
UF
allele was altered by a valine (GTG) to glutamate (GAG) substitution in exon 3 (residue 76). Two mutations were detected in the Brazzaville
UF
allele: a lysine (AAG) to methionine (ATG) substitution in exon 2 (residue 68) is responsible for the ultra-fast phenotype of this variant, while a tyrosine (TAT) to phenylalanine (TTT) substitution in exon 4 (residue 244) is not expected to alter the electrophoretic mobility of the encoded protein. These results indicate that the Gpdh
UF
alleles originate from different mutational events, and only two of them — Iowa
UF
and Netherlands
UF
— might share a common ancestry. The GPDH activity of the Iowa
UF
allele is intermediate between those of the Gpdh
S
and Gpdh
F
control stocks. The other Gpdh
UF
variants have lower activities than the controls: Xiamen
UF
-83%, Raleigh
UF
-80% and Brazzaville
UF
-73% of the Gpdh
F
control. 相似文献
64.
Normal and expanded Huntington's disease gene alleles produce distinguishable proteins due to translation across the CAG repeat. 总被引:7,自引:1,他引:6
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F. Persichetti C. M. Ambrose P. Ge S. M. McNeil J. Srinidhi M. A. Anderson B. Jenkins G. T. Barnes M. P. Duyao L. Kanaley et al. 《Molecular medicine (Cambridge, Mass.)》1995,1(4):374-383
BACKGROUND: An expanded CAG trinucleotide repeat is the genetic trigger of neuronal degeneration in Huntington's disease (HD), but its mode of action has yet to be discovered. The sequence of the HD gene places the CAG repeat near the 5' end in a region where it may be translated as a variable polyglutamine segment in the protein product, huntingtin. MATERIALS AND METHODS: Antisera directed at amino acid stretches predicted by the DNA sequence upstream and downstream of the CAG repeat were used in Western blot and immunohistochemical analyses to examine huntingtin expression from the normal and the HD allele in lymphoblastoid cells and postmortem brain tissue. RESULTS: CAG repeat segments of both normal and expanded HD alleles are indeed translated, as part of a discrete approximately 350-kD protein that is found primarily in the cytosol. The difference in the length of the N-terminal polyglutamine segment is sufficient to distinguish normal and HD huntingtin in a Western blot assay. CONCLUSIONS: The HD mutation does not eliminate expression of the HD gene but instead produces an altered protein with an expanded polyglutamine stretch near the N terminus. Thus, HD pathogenesis is probably triggered by an effect at the level of huntingtin protein. 相似文献
65.
Electrically induced calcium elevation,activation, and parthenogenetic development of bovine oocytes
Philippe Collas Rafael Fissore James M. Robl Eddie J. Sullivan Frank L. Barnes 《Molecular reproduction and development》1993,34(2):212-223
The influence of electrical stimulation on the level of intracellular Ca2+ in bovine oocytes, as well as activation and extent of parthenogenetic development, was investigated. Mature oocytes were electrically stimulated at 29 hr of maturation, and intracellular Ca2+ concentration was determined with the Ca2+ indicator fura-2 dextran (fura-2 D). The Ca2+ response of oocytes to a given electrical pulse was variable. Oocytes responded with either no Ca2+ rise from baseline (≈? 12 nM), a short-duration Ca2+ rise (from 12 nM to 300 nM) that returned to baseline within 2 min of the pulse, or a long-duration Ca2+ rise (from 12 nM to 1,000–2,000 nM) that never returned to baseline during the 8 min period over which the oocytes were monitored. In these oocytes, Ca2+ level returned to baseline when oocytes were removed from 0.30 M mannitol and placed in an ionic medium. Increasing field strength or pulse duration tended to increase the proportion of oocytes displaying a Ca2+ rise, and at 1.0 kVcm?1 for 40 μsec, all oocytes displayed a long-duration Ca2+ elevation. Direct transfer of oocytes from culture medium to mannitol also triggered a Ca2+ rise. Multiple stimulations, either electrical or by transferring to mannitol, produced multiple Ca2+ rises. This mannitol-induced Ca2+ rise could be inhibited by first washing the oocytes in medium containing equal parts of 0.30 M mannitol and phosphate buffered saline (PBS). The level of Ca2+ stimulation affected activation and development of oocytes. Insufficient, or, conversely, excessive Ca2+ stimulation impaired development. Optimum development was obtained with (1) three pulses of 0.2 kVcm?1 for 20 μsec, each pulse 22 min apart, after direct transfer of oocytes from culture medium to mannitol (22% blastocysts) or (2) three pulses of 1.0 kVcm?1 for 20 μsec after transfer of oocytes from culture medium to medium containing equal parts mannitol and PBS, then to mannitol (24% blastocysts). This procedure avoided induction of a Ca2+ rise prior to the pulse. The results indicate that the level of Ca2+ stimulation can be regulated by incubation conditions prior to the pulse and, to some extent, by field strength and pulse duration. The level of electrical stimulation influenced oocyte Ca2+ response, activation, and parthenogenetic development. © 1993 Wiley-Liss, Inc. 相似文献
66.
67.
Mark A. Tahmindjis Damien P. Higgins Michael J. Lynch Julie A. Barnes Colin J. Southwell 《Marine Mammal Science》2003,19(3):581-589
Between October and December of 1996–1999, off eastern Antarctica (60°-150°E), we darted 31 crabeater seals with midazolam and pethidine at estimated dose rates of 0.15–0.4 mg/kg and 1–3 mg/kg, respectively. Maximum sedation was reached at 23 ± 9 min (n = 18) and first signs of recovery were noted at 54 ± 24 min (n = 4). Seals greater than 250 kg body-mass were sedated by administration of approximately 90–100 mg midazolam and 600 mg pethidine, but the degree of sedation was unpredictable and did not permit invasive procedures in some cases. Behavior of the seal and adjacent conspecifics affected the success of procedures and our ability to monitor vital signs. Naloxone and flumazenil reversed sedation, making this combination attractive for use in animals adjacent to water. Additional ketamine was administered to two seals, resulting in improved restraint. 相似文献
68.
Jacqueline S. Knight Francisco Madueño Simon A. Barnes John C. Gray 《Molecular biotechnology》1996,6(3):335-345
The levels of individual photosynthetic proteins can be independently decreased by theAgrobacterium-mediated transformation of plants with antisens RNA constructs. Protocols for the introduction of such constructs intoAgrobacterium, theAgrobacterium-mediated transformation of tobacco leaf disks, and the screening and analysis of the transgenic plants produced are described. 相似文献
69.
V. Sreenivasa Reddy Kattesh V. Katti Charles L. Barnes 《Inorganica chimica acta》1995,240(1-2):367-370
The water-soluble bisphosphine, 1,2-bis(bis(hydroxymethyl)phosphino)ethane (1), was synthesized in near quantitative yield by the reaction of bisphosphine, H2PCH2CH2PH2, with an aqueous formaldehyde in the presence of K2PtCl4. The reaction of this water-soluble bisphosphine 1 with cis-Pt(COD)Cl2 affords the mononuclear bischelate complex, [Pt{(HOH2C)2PCH2CH2P(CH2OH)2}2](Cl)2 (2), in near quantitative yield. The new ligand and complex have been characterized spectroscopically and the structure of the metal complex, 2, was determined by X-ray crystallography. The Pt(II) complex 2 crystallizes in the orthorhombic space group Pbca(a=14.623(1), B=16.216(2), C=9.319(4) Å) with Z=4. The final R value is 0.024. 相似文献
70.
C. M. Christensen E. H. Barnes P. Nansen A. Roepstorff H. -C. Slotved 《International journal for parasitology》1995,25(12):1491-1498
This report describes the effect of different dose levels of infection upon worm burdens and development and fecundity of the parasites. Three groups each of 40, 9-week-old, helminth naïve pigs were inoculated once with either 2000 (group A), 20,000 (group B), or 200,000 (group C) infective third stage larvae of Oesophagostomum dentatum. Subgroups of 5 pigs from each major group were killed 3, 6, 11, 14, 18, 25, 34 and 47 days post inoculation (p.i.) and the large intestinal worm burdens were determined. Faecal egg counts were determined at frequent intervals after day 13 p.i. There were no overt clinical signs of gastrointestinal helminthosis during the experiment. Faecal egg counts became positive in groups A and B at around day 19 p.i., whereas most pigs in the high dose group C did not have positive egg counts until day 27–33 p.i. and some pigs remained with zero egg counts until the end of the study. Throughout the experiment the worm populations in group C consisted mainly of immature larval stages, while those in groups A and B were predominantly adult stages after days 14–18. Adult worms from the low dose group A were significantly longer than those from group C. At high population densities, stunted development of worms and reduced fecundity among female worms were found. Furthermore, there was a tendency for the distribution of the worms within the intestine to be altered with increasing population size. 相似文献