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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.
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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.
Localization of calcium in skeletal and cardiac muscle 总被引:3,自引:0,他引:3
Summary The requirement of calcium (Ca2+) in the excitation-contraction coupling of both skeletal and cardiac muscle is well established. However, the exact location of the intracellular storage sites of Ca2+ is not firmly established. We report here on the ultrastructural distribution of Ca2+ in white and red skeletal muscle and in cardiac muscle of the rat using combined phosphate-pyroantimonate (PPA) and oxalate-pyroantimonate (OPA) procedures. The methods are based on (a) stabilization and/or trapping of Ca2+ during the primary fixation step in glutaraldehyde by potassium phosphate or oxalate; (b) subsequent wash-out of all non-trapped cations such as Na+ and Mg2+ in potassium phosphate or oxalate; (c) conversion of the complexed or trapped Ca2+ into an electron-dense calcium pyroantimonate salt in 100 m-thick tissue sections; and (d) wash-out of the excess potassium pyroantimonate at alkaline pH.With the OPA procedure, mitochondria of all muscle types showed little precipitate. The junctional sarcoplasmic reticulum was stongly reactive in relaxed white skeletal muscle, negative in contracted white fibres and negative in red skeletal and cardiac muscle, independent of the state of relaxation-contraction. Other organelles were essentially free of deposits.With the PPA method, the precipitate was almost exclusively confined to the sarcolemma and its T-tubular invaginations in cardiac and slow skeletal muscle, and was absent in fast skeletal muscle. Apart from occasional deposits in mitochondria, all other organelles were free of precipitate. The sarcolemma-associated deposits were clearly confined to the inner leaflet of the lipid bilayer. The amount of precipitate varied within the contraction cycle, relaxed cells possessing the highest density.Exposure of the tissue to La3+ resulted in the complete absence of sarcolemma-bound precipitate suggesting that the Ca2+ is exchangeable. Furthermore, these cytological data suggest a basic difference in Ca2+ storage between white skeletal muscle on the one hand, and red skeletal and cardiac muscle on the other. 相似文献
4.
Csillag A. Bourne R. C. Patel Sanjay N. Stewart Michael G. Tömböl Teréz 《Brain Cell Biology》1989,18(3):369-379
Brain Cell Biology - The distribution of GABA-like immunoreactivity (GABA-LI) in the ectostriatal core (Ec) of domestic chicks (one to two days old) was investigated using (1) preembedding GABA... 相似文献
5.
Summary Moorland pools are shallow oligotrophic soft water lakes on poorly buffered sandy soils. Diatom assemblages of samples from 16 pools taken in 1920 and 1978 were compared by analysis of pH-spectra, diversity, dissimilarity and multivariate statistical techniques.The pH-spectra of pools in the southern (S) and central (C) part of the country indicate a fall in pH from 4.5–6.0 in the old samples to 3.7–4.6 in the recent ones. The pH-spectra of the northern pools (N) do not indicate a significant shift from the original pH (ca 4.5).The number of species in the count and the diversity (indices of Simpson and Shannon) decreased significantly in S+C, and that goes also for the dissimilarity index of Dyer. No changes were found in N.The first component (PC 1) of the principal component analysis explains 61% of total variance. PC 1 is correlated with log [SO4] (r=0.83, p<0.001) and even better (r=0.95, p<0.001) with the relative sulphate concentration,i.e. the ratio of sulphate to all major anions (sulphate, chloride, bicarbonate). All old samples have low scores on PC 1, recent samples have low scores on the second (PC 2) and third (PC 3) principal component. Old samples have high scores on PC 2 and PC 3, explaining 9 and 6% of total variance, respectively.The orginal variation, caused by regional factors, is replaced by a SO4
2– controlled variation. PC 1 is nearly completely determined by the relative abundance ofEunotia exigua. This species, which is known to be very resistant to pollution by sulphur, aluminium and heavy metals, increased largely from 1920 to 1978.In spite of the rather homogeneous distribution of wet sulphate deposition in the Netherlands, substantial differences in SO4
2– content in the pools are observed, being lowest in N (0.13–0.48 meq.l–1) and highest in S+C (0.38–1.65 meq.l–1). Sulphate is positively correlated with calcium, aluminum and magnesium but negatively with factors that characterize humic acid waters (e.g. permanganate-consumption, iron and the ratio of univalent to divalent cations). Sulphate concentration depends on the intensity of sulphate reduction, accumulation by dry deposition in surrounding forests of Scots pine, drought and atmospheric deposition. 相似文献
6.
Prado Valentina Cinelli Marco Ter Haar Sterre F. Ravikumar Dwarakanath Heijungs Reinout Guinée Jeroen Seager Thomas P. 《The International Journal of Life Cycle Assessment》2020,25(12):2393-2406
The International Journal of Life Cycle Assessment - Weighting in life cycle assessment (LCA) incorporates stakeholder preferences in the decision-making process of comparative LCAs. Research... 相似文献
7.
IMPROV-ED trial: eHealth programme for faster recovery and reduced healthcare utilisation after CABG
van Steenbergen G. J. van Veghel D. ter Woorst J. van Lieshout D. Dekker L. 《Netherlands heart journal》2021,29(2):80-87
Netherlands Heart Journal - After coronary artery bypass grafting (CABG), healthcare utilisation is high and is partly unplanned. eHealth applications have been proposed to reduce healthcare... 相似文献
8.
L. Santana M. Teijeira E. Uriartea C. Terán G. Andrei R. Snoeck 《Nucleosides, nucleotides & nucleic acids》2013,32(7-9):1337-1339
Abstract A series of new o ne t wo subtituted c arbonucleoside analogues (OTC) of purine was synthesized and evaluated against cytomegalovims and varicella-zoster virus in human embryonic lung (HEL) cells. 相似文献
9.
L. D. Ter Morshuizen A. K. Whitfield A. W. Paterson 《African Journal of Aquatic Science》2013,38(1-2):52-61
Summary Two and a half years of data were collected from the lower Great Fish River, head region and estuary to determine the fish species composition within these areas. Gilchristella aestuaria, Liza dumerilii, Rhabdosargus holubi and Pomadasys commersonnii were the four most abundant species captured, with riverine flow rate having an important effect on both species composition and numbers of fishes in the different regions. Most marine species displayed a strong inverse relationship between catch per unit effort and elevated freshwater inputs. Euryhaline marine species dominated the catches at all sampling sites during low flows but were less common during high flow periods when catadromous species were most abundant. Based on the available evidence it is suggested that for most marine species in the river this decline in abundance is related to low conductivity levels following floods rather than avoidance of elevated flows. The impact of elevated suspensoid concentrations and lowered dissolved oxygen concentrations on freshwater and estuarine fish populations during major river flooding is also discussed. 相似文献
10.
Daniel H. Lopez Maria A. Fiol-deRoque Maria A. Noguera-Salvà Silvia Terés Federica Campana Stefano Piotto José A. Castro Raheem J. Mohaibes Pablo V. Escribá Xavier Busquets 《PloS one》2013,8(8)