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1.
The alpha-like globin gene cluster in rabbits contains embryonic zeta-
globin genes, an adult alpha-globin gene, and theta-globin genes of
undetermined function. The basic arrangement of genes, deduced from
analysis of cloned DNA fragments, is 5'-zeta 0-zeta 1-alpha 1-theta 1- zeta
2-zeta 3-theta 2-3'. However, the pattern of restriction fragments
containing zeta- and theta-globin genes varies among individual rabbits.
Analysis of BamHI fragments of genomic DNA from 24 New Zealand white
rabbits revealed eight different patterns of fragments containing
zeta-globin genes. The large BamHI fragments containing genes zeta 0 and
zeta 1 are polymorphic in length, whereas a 1.9-kb fragment containing the
zeta 2 gene and the 3.5-kb fragment containing the zeta 3 gene do not vary
in size. In contrast to this constancy in the size of the restriction
fragments, the copy number of the zeta 2 and zeta 3 genes does vary among
different rabbits. No length polymorphism was detected in the BamHI
fragments containing the theta-globin genes, but again the copy number
varies for restriction fragments containing the theta 2 gene. The alpha 1-
and theta 1-globin genes are located in a nonpolymorphic 7.2-kb BamHI
fragment. The combined data from hybridization with both zeta and theta
probes shows that the BamHI cleavage pattern does not vary within the
region 5'-alpha 1-theta 1- zeta 2-zeta 3-theta 2-3', but the pattern
genomic blot-hybridization patterns for the progeny of parental rabbits
with different zeta-globin gene patterns shows that the polymorphic
patterns are inherited in a Mendelian fashion. Two different haplotypes
have been mapped based on the genomic blot-hybridization data. The
variation in the alpha-like globin gene cluster in the rabbit population
results both from differences in the copy number of the duplication block
containing the zeta-zeta-theta gene set and from the presence or absence of
polymorphic BamHI sites.
相似文献
2.
Trimethyloxonium modification of single batrachotoxin-activated sodium channels in planar bilayers. Changes in unit conductance and in block by saxitoxin and calcium 总被引:13,自引:9,他引:4 下载免费PDF全文
Single batrachotoxin-activated sodium channels from rat brain were modified by trimethyloxonium (TMO) after incorporation in planar lipid bilayers. TMO modification eliminated saxitoxin (STX) sensitivity, reduced the single channel conductance by 37%, and reduced calcium block of inward sodium currents. These effects always occurred concomitantly, in an all-or-none fashion. Calcium and STX protected sodium channels from TMO modification with potencies similar to their affinities for block. Calcium inhibited STX binding to rat brain membrane vesicles and relieved toxin block of channels in bilayers, apparently by competing with STX for the toxin binding site. These results suggest that toxins, permeant cations, and blocking cations can interact with a common site on the sodium channel near the extracellular surface. It is likely that permeant cations transiently bind to this superficial site, as the first of several steps in passing inward through the channel. 相似文献
3.
S. Pedler C. J. Fuery P. C. Withers J. Flanigan M. Guppy 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1996,166(6):375-381
We have examined metabolic depression in the land snail (Helix aspersa) during estivation, and have developed a tissue model of metabolic depression using an in vitro mantle preparation. The metabolic
rate of H. aspersa is depressed by 84% in vivo within 4 weeks of onset of estivation, and this metabolic depression is accompanied by a decrease
in haemolymph PO2 and pH, and an increase in haemolymph PCO2. The in vitro mantle preparation has a stable O2 consumption and energy charge, and an energy charge similar to that of mantle in vivo. The in vitro mantle is an O2-conforming tissue, with VO2 varying curvilinearly with PO2. Consequently, we have developed a mathematical method of calculating tissue VO2 at any PO2. These calculations show that under appropriate incubation conditions of pH and PO2, the mantle from estivating animals shows a stable in vitro metabolic depression of 48% compared to mantle from control snails.
The extrinsic effects of PO2 and pH account for 70% of the total in vitro metabolic depression of mantle tissue; intrinsic effectors contribute a further
30%.
Accepted April 26, 1996 相似文献
4.
Inhibition of lignin biosynthesis in Triticum aestivum L. rootsby Mn deficiency has been suggested as the mechanism of reducedresistance of Mn-deficient wheat roots to infection by the take-allfungus (Gaeumannomyces graminis var. tritici). This study evaluatedphenolics and lignin accumulation in roots of wheat genotypesdiffering in Mn efficiency (measured as growth and yield inMn-deficient soils) and take-all resistance. Seedlings of theMn-inefficient, take-all sensitive genotype Bayonet and theMn-efficient, more take-all resistant genotype C8MM were grownin nutrient solution without added Mn for 18 d and then transferredto a Mn-deficient sandy soil fertilized with Mn at 0 or 30 mgkg-1. Both genotypes had Mn-deficient roots and shoots at thetime of transfer to the soil. Roots of both genotypes were inoculatedwith the take-all fungus 0, 1, 3 and 7 d after transfer. Twenty-fourhours after inoculation, take-all fungus penetrated the rootstele of take-all sensitive Bayonet but not of more resistantC8MM wheat. Rates of phenolics and lignin accumulation in rootsdeclined steadily during growth in soil for up to 8 d, werehigher in mature, fully differentiated parts of the root systemcompared to distal, younger root tissue, and were higher inBayonet than in C8MM. Manganese fertilization did not significantlyinfluence rates of phenolics and lignin accumulation but reduceddepth of radial penetration by hyphae in both genotypes. Therate of phenolics accumulation was positively (r = 0·91to 0·96) correlated with the rate of lignin accumulation.Mn-efficient C8MM had a higher rate of lignin accumulation perunit of phenolics than Mn-inefficient Bayonet over a wide rangeof phenolics synthesis rates. From this we suggest that C8MMhas a more efficient mechanism for conversion of phenolics tolignin, the trait which appears related to higher take-all resistanceof this genotype.Copyright 1994, 1999 Academic Press Gaeumannomyces graminis var. tritici, lignin, manganese, phenolics, resistance, roots, Triticum aestivum 相似文献
5.
Abstract Opportunistic sightings and strandings of Caperea marginata (n=196) from the vicinity of Australia and New Zealand (1884 to early 2007) were used to relate geographic and temporal patterns to oceanographic and broad-scale climatic variability. Records were not uniformly distributed along the coast and more (69%) were from Australia than New Zealand. Seven coastal whale ‘hotspots’ were identified which accounted for 61% of records with locality data. Half of the hotspot records were from southeast (37) and northwest (20) Tasmania—others each had 9–15 events. Upwelling and/or high zooplankton abundance has been documented near all whale hotspots. Records of C. marginata occurred in all months, with 75% in spring and summer. Inter-annual variability showed broad agreement between increased whale records (usually in spring/summer) and strongly positive ‘Niño 3.4’ during 1980–1995 but not thereafter. Coastal upwelling and productivity increase during climatic phenomena such as El Niño and are likely to be quickly beneficial to plankton-feeding whales such as C. marginata. 相似文献
6.
Jolanda?HM?van Bilsen Josée?PA?Wagenaar-Hilbers Maarten?JF?van der Cammen Mariska?EA?van Dijk Willem?van Eden Marca?HM?WaubenEmail author 《Arthritis research & therapy》2002,4(4):R2
We have recently found that matrix metalloproteinases (MMPs) are targets for T-cell and B-cell reactivity in experimental
arthritis. In the present article, we investigate whether modulation of MMP-specific T-cell responses could influence the
course of adjuvant arthritis (AA). Lewis rats were treated nasally with MMP peptides prior to or after AA induction. Administration
of the MMP-10 or the MMP-16 peptide prior to AA induction reduced the arthritic symptoms. In contrast, administration of the
MMP-10 peptide after AA induction aggravated the arthritic symptoms. The present study shows the possible usefulness of MMP
peptides for immunotherapy. However, a clear understanding of proper timing of peptide administration is crucial for the development
of such therapies. 相似文献
7.
8.
Charlie Strange Felix JF Herth Kevin L Kovitz Geoffrey McLennan Armin Ernst Jonathan Goldin Marc Noppen Gerard J Criner Frank C Sciurba 《BMC pulmonary medicine》2007,7(1):1-12
Background
Lung volume reduction surgery is effective at improving lung function, quality of life, and mortality in carefully selected individuals with advanced emphysema. Recently, less invasive bronchoscopic approaches have been designed to utilize these principles while avoiding the associated perioperative risks. The Endobronchial Valve for Emphysema PalliatioN Trial (VENT) posits that occlusion of a single pulmonary lobe through bronchoscopically placed Zephyr® endobronchial valves will effect significant improvements in lung function and exercise tolerance with an acceptable risk profile in advanced emphysema.Methods
The trial design posted on Clinical trials.gov, on August 10, 2005 proposed an enrollment of 270 subjects. Inclusion criteria included: diagnosis of emphysema with forced expiratory volume in one second (FEV1) < 45% of predicted, hyperinflation (total lung capacity measured by body plethysmography > 100%; residual volume > 150% predicted), and heterogeneous emphysema defined using a quantitative chest computed tomography algorithm. Following standardized pulmonary rehabilitation, patients were randomized 2:1 to receive unilateral lobar placement of endobronchial valves plus optimal medical management or optimal medical management alone. The co-primary endpoint was the mean percent change in FEV1 and six minute walk distance at 180 days. Secondary end-points included mean percent change in St. George's Respiratory Questionnaire score and the mean absolute changes in the maximal work load measured by cycle ergometry, dyspnea (mMRC) score, and total oxygen use per day. Per patient response rates in clinically significant improvement/maintenance of FEV1 and six minute walk distance and technical success rates of valve placement were recorded. Apriori response predictors based on quantitative CT and lung physiology were defined.Conclusion
If endobronchial valves improve FEV1 and health status with an acceptable safety profile in advanced emphysema, they would offer a novel intervention for this progressive and debilitating disease.Trial Registration
ClinicalTrials.gov: NCT00129584 相似文献9.
Orange S Rasko JE Thompson JF Vaughan J Olive E Pedler M Horvath JS Hennessy A 《Cytokine》2005,29(4):176-185
OBJECTIVES: In pregnancy, the placental contribution of cytokines to maternal immunosuppression has been established, however their role in normal maternal blood pressure regulation has not been identified. We investigate the contribution of interleukin-10 (IL-10) and tumor necrosis factor-alpha (TNF-alpha) to the vasodilation of early pregnancy in non-human primates. We also sequenced the IL-10 baboon gene and compared it with humans. METHODS: The effect of four different treatments, administered sequentially (semi-random-design) on resting 18h, night time, or hourly mean arterial pressure (MAP) and heart rate (HR) were measured using telemetry. An anti-human IL-10 monoclonal antibody (MAb, 1mg, n=7), anti-TNF-alpha antibody (n=3), a combination of anti-IL-10 and anti-TNF-alpha antibodies (n=5) or saline (n=3) control were administered intravenously to baboons in early pregnancy. Plasma and placental IL-10 concentration was measured before and after injection in all animals. RESULTS: Anti-human IL-10 MAb caused a significant increase in MAP of 2.6+/-0.5mmHg over the 18-h period (p<0.05). Administration of TNF-alpha alone or in combination with IL-10 did not alter MAP. There was 97% sequence homology of IL-10 cDNA between humans and baboons. CONCLUSIONS: IL-10 was shown to regulate the vasodilation of early pregnancy in Papio hamadryas. This partial role of IL-10 in the early BP response of primate pregnancy may be relevant to pathophysiological states of human pregnancy such as preeclampsia. 相似文献
10.
Liliane?VenturaEmail author Gabriel?Torres?de Jesus Gunter?Camilo Dablas?de Oliveira Sidney?JF?Sousa 《Biomedical engineering online》2005,4(1):70