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21.
ИЗyчaл0C044A; Bлияниe НeкOTOpыX ФaкTopoB (pH, OTHoшeниe КpacиTeля к бeлкy, КOнпeнTpaция КOMпoнeнTOB, пpиcyTcTBиe opraничecкиX pacTBopиTeлeй B peaгиpyюшeй cмecи, TeMпepaTypa, Bpeмя peaкции) Ha эффeкTиBн0CTъ кOнъюгaции γ-глoбyлинa c флyopecцeинизOTиoциaнaTOM. КoличecTBO КpacиTeля, CBязaннoгo c γ-глoбyлинOM, знaч иTeлънO пoBышaлocъ, кoгдa пoBышaлcя B пpeдeлax 7,0–10,0pH peaгиpyющeй cмeCи, Toгдa кaк ocTaлъныe фaкTopы нe oкaзыBaли нa мeчeныe бeлки B иccлeдyeмыx пpeдeлax cyщecTBeннoгo Bлияния. БылO ycTaнOBлeнo, чTO cпeцифичecкaя флyopecцeнпия cBязaннoгo кpacиTeля зaмeTнo пoнижaлacъ c пOBышeниeм мeчeннOcTи бeлкOB, a пoэTOмy нaибoлee цeлecooбpaзным пpeдcTaBляeTCя иcпoлъзOBaниe для мeTOдa флyopecцeнTныx aнTиTeл-кOнъюгaTOB c BecoBым COOTнOшeниeм бeлкOB и кpacиTeля, paBным пpиблизиTeльнO 60. 相似文献
22.
23.
D L Albrecht J W Mills R J Noelle 《Journal of immunology (Baltimore, Md. : 1950)》1990,144(9):3251-3256
The proposed function of intermediate filaments is to provide a cell type-specific structural framework that maintains cell shape and organelle distribution and mediates signal transduction through its connections with the plasma membrane and the nucleus. Vimentin is the intermediate filament protein expressed in B lymphocytes. Immunocytochemical analysis of the high salt-stable cytoskeletons from B cells stimulated with anti-Ig revealed an increased accumulation of vimentin in the cytoskeleton compared to nontreated controls. This increased accumulation of vimentin in the cytoskeleton was manifested by the organization of vimentin into extensive filamentous arrays (EFA) as viewed in the fluorescent microscope. In contrast to the effects of anti-Ig, activation of B cells with LPS did not induce the organization of vimentin into EFA. This suggested that signals unique to anti-Ig directed EFA formation. Immunocytochemical results were verified by biochemical analysis showing that vimentin was more abundant in isolated cytoskeletons from anti-Ig activated B cells, than cytoskeletons isolated from LPS-activated B cells. These observations established a relationship between increased content of vimentin in the cytoskeleton and the formation of EFA. By testing a wide variety of activating agents, we were able to correlate increased vimentin expression in the cytoskeleton to activating agents that cross-link membrane Ig. It appeared that treatment of B cells with LPS prohibited the induction of EFA by anti-Ig because cotreatment with both anti-Ig and LPS resulted in decreased vimentin accumulation in the cytoskeleton to a level less than that in resting cells. The significance of these results with regard to B cell biology is discussed. 相似文献
24.
25.
Compensation of respiratory alkalosis induced after acclimation to simulated altitude 总被引:1,自引:0,他引:1
Gonzalez N. C.; Albrecht T.; Sullivan L. P.; Clancy R. L. 《Journal of applied physiology》1990,69(4):1380-1386
Conscious intact rats previously acclimated for 3 wk to barometric pressure of 370-380 Torr (3WHx) were made alkalotic for 3 h by a decrease in inspired O2 fraction from 0.10 to 0.075 at ambient barometric pressure (730-740 Torr). Controls were normoxic littermates (Nx) in which inspired O2 fraction was lowered from approximately 0.21 to 0.10 for 3 h. Arterial PCO2 decreased progressively and similarly in both groups (65-70% of control at 15 min). Initially, arterial pH increased less in 3WHx (0.09 +/- 0.004 vs. 0.15 +/- 0.008). As hypocapnia continued, delta[HCO3-]/delta pH (mmol.l-1.pH) became more negative in Nx, from -15.2 +/- 2.5 at 15 min to -37.0 +/- 2.9 at 3 h, indicating nonrespiratory compensation of alkalosis. In 3WHx, delta[HCO3-]/delta pH did not change during alkalosis. Cumulative renal excretion of base (mueq/100 g) during alkalosis increased by 73.2 +/- 11.1 in Nx and 25.4 +/- 7.3 in 3WHx. This difference was mainly due to a larger increase in HCO3- excretion in Nx. The data suggest that the smaller compensation of hypocapnic alkalosis in 3WHx is partly due to the smaller increase in renal base excretion. Because base availability limits renal base excretion, the smaller renal response of 3WHx may be secondary to the low plasma HCO3- concentration that accompanies altitude acclimation. 相似文献
26.
Candida bombicola ATCC 22214 produces the glycolipid sophoroselipid when cultivated on a medium with glucose as the sole carbon source. Under
phosphate-limiting conditions the product yield rises from 0.033 to 0.143 and the specific product formation rate rises from
0.004 h-1 to 0.007 h-1. Enhanced sophoroselipid synthesis is initiated by the decline of the specific activities of NAD- and NADP-dependent isocitrate
dehydrogenase (EC 1.1.1.41 and 1.1.1.42) to 2% and 0% of the initial activities respectively. Constantly high specific activity
of citrate synthase (EC 4.1.3.7) causes an accumulation of isocitrate and citrate in the mitochondria. Both acids are transported
into the cytosol where citrate is cleaved by ATP: citrate lyase (EC 4.1.3.8) giving rise to acetyl-CoA, the precursor of fatty
acid synthesis. The ATP: citrate lyase is unaffected by different energy charges; the apparent K
m values for coenzyme A, ATP and citrate are 23 μM, 250 μM and 256 μM respectively. NADPH for fatty acid synthesis might be
generated by further metabolism of oxaloacetate, the other product of the citrate-cleaving reaction, by oxidation of the isocitrate
by the cytosolic NADP-dependent isocitrate dehydrogenase or via the hexose monophosphate shunt. A possible explanation for
sophoroselipid formation during exponential growth is given.
Received: 7 November 1995/Received revision: 19 March 1996/Accepted: 25 March 1996 相似文献
27.
A male patient carrying an interstitial deletion in Xp22.3 and affected by Kallmann syndrome, X-linked ichthyosis and mental retardation, but without chondrodysplasia punctata or short stature, was investigated with molecular probes from the distal Xp22.3 region. By means of a novel probe, M115, from the relevant region, the distal deletion breakpoint was shown to be between 3.18 and 3.57 Mb from Xptel. As the patient is not affected by X-linked recessive chondrodysplasia punctata, the gene for this disease can therefore be located to within an interval of less than one megabase proximal to the pseudoautosomal boundary. If the chondrodysplasia punctata gene is associated with a CpG island, this leaves only two islands at 2760 and 3180 kb from the Xp telomere as the most promising candidate sites for this gene. 相似文献
28.
20-OH-ecdysone swells nuclear volume by alkalinization in salivary glands of Drosophila melanogaster
Stefan Wünsch Stefan Schneider Albrecht Schwab Hans Oberleithner 《Cell and tissue research》1993,274(1):145-151
Ecdysteroids play an important role in the larval moulting process of insects. Ecdysone-induced stimulation causes specific puffs in polytene chromosomes of salivary gland cells resulting in nuclear swelling. During this process, changes of intracellular ion composition are thought to act as an early regulatory mechanism of gene activation. By use of video-imaging analysis and electrophysiological techniques, we examined ecdysone-induced nuclear swelling in Drosophila salivary glands in situ and its dependence on pH and calcium. Isolated glands of the third larval stage were superfused with a solution mimicking the haemolymph. Addition of 5×10–6 mol/l 20-OH-ecdysone led, after a lag period of 50 min, to a sustained Ca2+-dependent increase of nuclear volume by 23.0±2.3%. Amiloride, a blocker of plasma membrane Na+/H+ exchange, prevented 20-OH-ecdysone-induced nuclear swelling. Decreasing pH in the superfusate from 7.15 to 6.8 led to nuclear shrinkage by 16.9±3.9%. Measurments of pH in salivary gland cells with ion-sensitive microelectrodes disclosed an alkalinization of 0.23±0.05 pH units after stimulation with 20-OH-ecdysone. We postulate that 20-OH-ecdysone activates the amilorde-sensitive plasma membrane Na+/H+ exchanger. This leads to intracellular alkalinization and concomitant decondensation of the nuclear chromatin visible as nuclear swelling. Thus, cell alkalinization could be a potentially important stimulatory mechanism in mediating ecdysteroid-induced activation of the cell nucleus. 相似文献
29.
mtDNA diversity in rhesus monkeys reveals overestimates of divergence time and paraphyly with neighboring species 总被引:4,自引:0,他引:4
Reconstructions of the human-African great ape phylogeny by using
mitochondrial DNA (mtDNA) have been subject to considerable debate. One
confounding factor may be the lack of data on intraspecific variation. To
test this hypothesis, we examined the effect of intraspecific mtDNA
diversity on the phylogenetic reconstruction of another Plio- Pleistocene
radiation of higher primates, the fascicularis group of macaque (Macaca)
monkey species. Fifteen endonucleases were used to identify 10 haplotypes
of 40-47 restriction sites in M. mulatta, which were compared with similar
data for the other members of this species group. Interpopulational,
intraspecific mtDNA diversity was large (0.5%- 4.5%), and estimates of
divergence time and branching order incorporating this variation were
substantially different from those based on single representatives of each
species. We conclude that intraspecific mtDNA diversity is substantial in
at least some primate species. Consequently, without prior information on
the extent of genetic diversity within a particular species, intraspecific
variation must be assessed and accounted for when reconstructing primate
phylogenies. Further, we question the reliability of hominoid mtDNA
phylogenies, based as they are on one or a few representatives of each
species, in an already depauperate superfamily of primates.
相似文献
30.
Rainer Klocke Steven L. Roberds Michael M. Tamkun Monika Gronemeier Andr Augustin Barbara Albrecht Olaf Pongs Harald Jockusch 《Genomics》1993,18(3)
The four Shaker-like subfamilies of Shaker-, Shab-,Shaw-, and Shal-related K+ channels in mammals have been defined on the basis of their sequence homologies to the corresponding Drosophila genes. Using interspecific backcrosses between Mus musculus and Mus spretus, we have chromosomally mapped in the mouse the Shaker-related K+-channel genes Kcna1, Kcna2, Kcna4, Kcna5, and Kcna6; the Shab-related gene Kcnb1; the Shaw-related gene Kcnc4; and the Shal-related gene Kcnd2. The following localizations were determined: Chr 2, cen-Acra-Kcna4-Pax-6-a-Pck-1-Kras-3-Kcnb1 (corresponding human Chrs 11p and 20q, respectively); Chr 3, cen-Hao-2-(Kcna2, Kcnc4)-Amy-1 (human Chr 1); and Chr 6, cen-Cola-2-Met-Kcnd2-Cpa-Tcrb-adr/Clc-1-Hox-1.1-Myk-103-Raf-1-(Tpi-1, Kcna1, Kcna5, Kcna6) (human Chrs 7q and 12p, respectively). Thus, there is a cluster of at least three Shaker-related K+-channel genes on distal mouse Chr 6 and a cluster on Chr 2 that at least consists of one Shaker-related and one Shaw-related gene. The three other K+-channel genes are not linked to each other. The map positions of the different types of K+-channel genes in the mouse are discussed in relation to those of their homologs in man and to hereditary diseases of mouse and man that might involve K+ channels. 相似文献