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1.
Summary Whole-blood cells of obligate carriers of the X-linked Wiskott-Aldrich syndrome (WAS) exhibit nonrandom inactivation of the X-chromosomes. However, because of the limited polymorphism of the probes available, the X-methylation pattern can only be determined in a restricted proportion of females. We thus analysed a large set of normal females and members of WAS families, using the recently described marker M27, which detects the hyperpolymorphic locus DXS255. The probe was used to detect differences in methylation between the active and inactive X-chromosome, and the findings were compared with the pattern obtained using the well-documented probes from the 5 end of the PGK and HPRT genes. All the normal females were found to use either X-chromosome randomly, and there was complete correlation between the three probes in the populations studied. Segregation analysis performed with M27 and other related markers in the WAS families was fully in accordance with the X-inactivation data. The use of M27, for both X-inactivation and segregation analysis of WAS kindreds, provides a basis for genetic counselling in the majority of families, including those with no surviving males.  相似文献   

2.
Sialic acids and the majorO-glycosidic oligosaccharide of glycophorin MK from monkey (Japanese monkey,Macaca fuscata) erythrocyte membranes were characterized.N-Glycolylneuraminic acid (neu5Gc) was found as the major sialic acid, which was confirmed by gas-liquid chromatography-mass spectrometry as the trimethylsilyl methyl ester. ThreeO-glycosidic oligosaccharide units were obtained from a tryptic glycopeptide that contained all of the carbohydrate units in glycophorin MK by mild alkaline borohydride/borotritide treatment. Carbohydrate analyses of the oligosaccharides revealed that they were composed of Neu5Gc, galactose andN-acetylgalactosaminitol in the molar ratios of 111 (trisaccharide), 211 (tetrasaccharide) and 111 (pentasaccharide). The content of oligosaccharide units was estimated to be 1125 for penta-, tetra- and trisaccharide, respectively, based on the yields, the molecular weight, and the number of oligosaccharide attachment sites in the amino-acid sequence. The tetrasaccharide was the major oligosaccharide and its structure was proposed to be Neu5Gc2-3Gal1-3[Neu5Gc2-6]GalNAcol.  相似文献   

3.
The effect of carbonnitrogenphosphorus (CNP) ratio of organic substrates on the regeneration of ammonium and phosphate was investigated by growing natural assemblages of freshwater bacteria in mineral media supplemented with the simple organic C, N, and P sources (glucose, asparagine, and sodium glycerophosphate, respectively) to give 25 different substrate CNP ratios. Both ammonium and phosphate were regenerated when CN and NP atomic ratios of organic substrates were 101 and 161, respectively. Only ammonium was regenerated when CN and NP ratios were 101 and 10–201, respectively. On the other hand, neither ammonium nor phosphate was regenerated when CN and NP ratios were 151 and 51, respectively. In no case was phosphate alone regenerated. As bacteria were able to alter widely the CNP ratio of their biomass, the growth yield of bacteria appeared primarily dependent on the substrate carbon concentration, irrespective of a wide variation in the substrate CNP ratio.  相似文献   

4.
Calf lens A-crystallin isolated by reversed-phase HPLC demonstrates a slightly more hydrophobic profile than B-crystallin. Fluorescent probes in addition to bis-ANS, like cis-parinaric acid (PA) and pyrene, show higher quantum yields or Ham ratios when bound to A-crystallin than to B-crystallin at room temperature. Bis-ANS binding to both A- and B-crystallin decreases with increase in temperature. At room temperature, the chaperone-like activity of A-crystallin is lower than that of B-crystallin whereas at higher temperatures, A-crystallin shows significantly higher protection against aggregation of substrate proteins compared to B-crystallin. Therefore, calf lens A-crystallin is more hydrophobic than B-crystallin and chaperone-like activity of -crystallin subunits is not quantitatively related to their hydrophobicity.  相似文献   

5.
With relative phase as a collective variable or order parameter, phase attractive dynamics can capture the temporally coherent behavior of a large number of different experimental systems. We present results from multifrequency coordination experiments in humans showing: a) that phase attraction persists especially for low order frequency ratios; b) that short-term jumps from one phase relation to another occur within a frequency ratio; c) that the most stable frequency-ratios are low order; and d) that transitions frequently occur from higher order (e.g. 52, 43) to lower order (21, 11) frequency ratios. We study a modified sine circle map with built-in phase attractive dynamics that qualitatively accounts for these results. In this phase-attractive map, patterns arise from competition between external driving and intrinsic phase attractive dynamics. The relative strength of extrinsic and intrinsic parameters determines the width of Arnol'd tongues, thereby influencing the delay or acceleration of irregular behavior. Behavioral complexity is inversely proportional to tongue width, thus accounting for the relative difficulty of performing different multifrequency behaviors and why errors in such behavior are often seen to occur.  相似文献   

6.
The interference of hyperthermia and ionizing radiation, respectively, with the effects of capric (100), lauric (120), myristic (140), oleic (cis-181) and elaidic (trans-181) acids on the osmotic resistance of human erythrocytes was investigated. The results are summarized as follows: (A) not only at 37°, but also at 42° and 47°C lauric acid (120) represents the minimum chain length for the biphasic behaviour of protecting against hypotonic hemolysis at a certain lower concentration range and hemolysis promotion at subsequent higher concentrations; (B) with increasing temperatures the protecting as well as the hemolytic effects occur at lower concentrations of the fatty acids; (C) the increase of temperature promotes the extent of hemolysis and reduces the extent of protection against hypotonic hemolysis; (D) Gamma-irradiation of erythrocytes selectively affects the concentration of oleic acid at which maximum protection against hypotonic hemolysis occurs, without altering the minimum concentration for 100% hemolysis.  相似文献   

7.
Summary In nondiapause adults raised under a long-day photoperiod, the critical daylength for diapause induction was between 13 and 14 h although some individuals did not respond to the short-day photoperiod and went on laying eggs. In postdiapause adults in which LD 1311 induced the first diapause (L13 insects), the critical daylength for diapause reinduction was between 13 and 14 h, whereas it was between 12 and 13 h in postdiapause adults in which LD 1014 induced the first diapause (L10 insects). Under LD 1311, a small proportion of L10 insects went into the second diapause after great delay as compared with L13 insects. Under LD 1014, on the other hand, L10 insects went into the second diapause more rapidly than L13 insects. Therefore, the photoperiod which had induced the first diapause affected the photoperiodic induction of the second diapause not only in the critical daylength but also in the speed of response. In Riptortus clavatus, the photoperiodic history influences the subsequent photoperiodic response even after a physiological state induced by the previous photoperiod was terminated completely.Abbreviations L13 insects postdiapause adults in which LD 1311 induced the first diapause - L10 insects postdiapause adults in which LD 1014 induced the first diapause  相似文献   

8.
Petrobia harti (Ewing) diapauses in the egg stage. Adult females lay either diapause or nondiapause eggs. On the University of Thessaloniki campus (41°N), the mite was found to develop on leaves ofOxalis corniculata L. throughout the year, while no mites were found on leaves ofOxalis articulata Savigny growing in the same area. In the laboratory the mite could be maintained equally well on detached leaves of both plant species, kept on wet cotton-wool.Forty to 90% females laying diapause eggs (dlf) were produced when the mites developed under LD 1212 and 19±1 °C, or LD 168 and 19±1 °C or 25±1 °C on leaves ofO. articulata detached from plants grown in the open in various seasons. Under the same conditions, a very low to zero percentage ofdlf was produced onO. corniculata. By rearing certain feeding stages on one of these twoOxalis hosts, and the other feeding stages on the other host, various percentages ofdlf were obtained. These percentages were the net effect of the antagonistic action of the twoOxalis species.By rearing the mites at LD 8.515.5, LD 1212 or LD 168 and a temperature of 19±1 °C onO. articulata leaves renewed every 3 days, or every 16–18 days, or not at all, it could be shown that diapause induction or aversion is caused by the direct effect of photoperiod on the mites, and not by an effect through the host leaves.When wholeO. articulata plants were grown under LD 168 and 19±1 °C in the laboratory, or developed in the open during April and May, flowers were produced, while under LD 1212 no flowering occurred. In the laboratory under diapause-inducing conditions, higher percentages ofdlf were produced on leaves detached from flowering plants than on leaves detached from plants not flowering.OnO. articulata leaves at 20 °C, photoperiods with photophases equal to or longer than 12 h induced from 70 to 80%dlf, while photoperiods with photophases equal to or shorter than 10.9 h induced very low to zero percentages. By transferring different chrysalis stages from a diapause-inducing (LD 1212) to a diapause-averting (LD 8.515.5) photoperiod, and vice versa, it was found that the nymphochrysalis through deutonymph stages were sensitive to photoperiod, the deutochrysalis and deutonymph being the most sensitive.Under an LD 1212 photoperiod, a temperature of 20 °C induced diapause, whereas 25 °C, 30 °C, or a daynight thermoperiod of 25 °C18 °C suppressed it.  相似文献   

9.
Summary Differential counts of the leucocytes of newts,Notophthalmus viridescens, were made at four times of day (200, 900, 1400 and 2100), 72 hours after the injection of hydrocortisone acetate (experimentais) or distilled water (controls). At all times, increases in neutrophils and decreases in lymphocytes were observed in experimentais as compared to the controls (Table 1). The increases in neutrophils in the experimental newts were most pronounced at 1400, and the decreases in the lymphocytes were greatest at 2100. The least degrees of neutrophilia and lymphopenia occurred at 900. Consequently, circadian variations in response to the hydrocortisone are indicated. The possible mechanism of mediation of the variations is discussed.Supported in part by National Science Foundation grant, GY-7661, to Sweet Briar College.  相似文献   

10.
On age morphological changes of males of Chydoridae (Cladocera)   总被引:2,自引:2,他引:0  
N. N. Smirnov 《Hydrobiologia》1967,30(3-4):555-571
Summary Young and adult males of 11 species of Chydoridae are studied, their figures being published here (fig. 1–15). The necessity is stressed to distinguish young forms of males and gynandromorphic individuals.Pleuroxus balatonicus is considered to be described from the population ofPleuroxus unicatus having under Balaton Lake conditions retarded transformation of young males into adult form, and accordingly having unusually numerous young males. \qO\qs\qn\qo\qv\qn\qy\ye \qr\ye\qz\qu\ql\Qj\qt\qa\qt\qy 11 (. 1–15). . , Pleuroxus uncinatus , Pleuroxus balatonicus.  相似文献   

11.
This paper presents evidence that short-term exposure to light increases synthesis of hydroxyei-cosatetraenoic acid (HETE) and prostaglandin D2 (PGD2) and stimulates the uptake and metabolism of 204 in phospholipids and triacylglycerols in rat retina. There was a time-dependent increase in incorporation of 1-14C-204 into glycerolipids in both dark-adapted and light-exposed groups. Exposure to light for 15 or 30 min enhanced the acylation of 204 into phosphatidylcholine, phosphatidylinositol, phosphatidylethanolamine and triacylglycerols. In the light-exposed groups there was a large increase in the conversion of 204 to leukotriene B4, two diHETEs, 5-HETE, 15-HETE, and PGD2. The stimulation of HETE synthesis by light could be due to early stages of light-induced lipid peroxidation in visual cells. To examine this, we studied peroxidation of 204 in isolated rod outer segments (ROS). There was more oxidation of 204 in light-exposed ROS, as compared to ROS incubated in the dark. Vitamin E and nordihydroguaiaretic acid inhibited the light-induced formation of some of these products. The data indicate that photo-oxidation of 204 in ROS is accompanied by enzymatic oxygenation that is stimulated by light. Increased production of HETEs and PGD2 may be a consequence of the light-induced stimulation of the metabolism of 204 in membrane phospholipids in the retina.  相似文献   

12.
This study characterizes free fatty acid release in a neuroblastoma cell line (Neuro-2A), a potential model system for the study of factors that control phospholipase A2 in neurons. Two compounds, bicuculline (an antagonist at -aminobutyric acid receptors), and A23187 (a Ca2+ ionophore), were examined. The release of endogenous fatty acids and the turnover of radiolabeled arachidonic and docosahexaenoic acids were measured. The cells actively incorporated radiolabeled fatty acids into various glycerolipid pools. Both endogenous fatty acids and radiolabeled fatty acids were released from glycerolipids in a time-dependent manner. Phosphatidylcholine was a major source of released fatty acids. Release of free fatty acids was markedly stimulated by both bicuculline and A23187. We conclude that the Neuro-2A cell contain phospholipase activity that is sensitive to Ca2+ ionophore and bicuculline, and may provide a good system for further studies on the regulation of phospholipase A2 in neurons.Abbteviations 160 palmitic acid - 180 stearic acid - 181 oleic acid - 182 linoleic acid - 183 linolenic acid - 204 arachidonic acid - 226 docosahexaenoic acid - DG diacylglycerol - FAME fatty acid methyl ester - FFA free fatty acid - GABA -aminobutyric acid - PA phosphatidic acid - PC phosphatidylcholine - PE phosphatidylethanolamine - PI phosphatidylinositol - PS phosphatidylserine - TG triacylglycerol  相似文献   

13.
An -tocopherol-binding protein has been isolated and purified from rabbit heart cytosol. The purified protein had an apparent molecular mass of 14,200, as derived from SDS-PAGE. The content of the protein in rabbit heart was around 11.8 g per g of tissue. The binding of -tocopherol to the purified protein was rapid, reversible, and saturable. Neither nor tocopherol could displace the bound -tocopherol from the protein, suggesting a high specificity for -tocopherol. -Tocopherol-binding protein did not bind oleate. Transfer of -tocopherol from liposomes to mitochodria was stimulated 8-fold in the presence of the binding protein, suggesting that this protein may be involved in the intracellular transport of -tocopherol in the heart.  相似文献   

14.
Summary We compared the Feulgen hydrolysis curves (37° C, 5 M HCl) of human blood lymphocytes fixed by the following four methods: 96% ethanol, 60 min at 20° C; ethanol-acetone, 11, 120 min at 4° C; ethanolglacial acetic acid mixture (31), containing 2% of formaldehyde (EAF), 90 min at 20° C; and ethanol-glacial acetic acid (31), 60 min followed by 5% chrome alum solution for 360 min at 20° C. The best results were obtained with EAF-fixation, with respect to the highest amount of DNA-Schiff complex at the peak point of the curve, the longest plateau region and the smallest scattering of DNA-Schiff amount values along the plateau. With other types of fixation the addition of polyethylene glycol (PEG) 6,000 to the hydrolysis solution resulted in modification of the shape of the hydrolysis curve so that it became nearly similar to the EAF-curve. The effect of PEG6000 on the EAF-curve was minimal. Slides fixed by ethanol were used for a comparison of polyethylene glycols with m.w. 1,500, 6,000 and 20,000. The longest plateau was obtained with PEG6000. The only effect of PEG1500 was a dramatic increase of DNA-Schiff amount at the peak point. PEG20000 had no significant effect on the shape of the hydrolysis curve. The results are discussed in terms of Kjellstrand's chain with a stable structure model of Feulgen hydrolysis.  相似文献   

15.
A linkage map with RFLP and isozyme markers for almond   总被引:12,自引:0,他引:12  
Inheritance and linkage studies were conducted with seven isozyme genes and 120 RFLPs in the F1 progeny of a cross between almond cultivars Ferragnes and Tuono. RFLPs were detected using 57 genomic and 43 cDNA almond clones. Eight of the cDNA probes corresponded to known genes (extensin, prunin (2), -tubulin, endopolygalacturonase, oleosin, actin depolymerizing factor and phosphoglyceromutase). Single-copy clones were found more frequently in the cDNA (65%) than in the genomic libraries (26%). Two maps were elaborated, one with the 93 loci heterozygous in Ferragnes and another with the 69 loci heterozygous in Tuono. Thirty-five loci were heterozygous in both parents and were used as bridges between both maps. Most of the segregations (91%) were of the 11 or 1111 types, and data were analyzed as if they derived from two backcross populations. Eight linkage groups covering 393 cM in Ferragnes and 394 in Tuono were found for each map. None of the loci examined in either map was found to be unlinked. Distorted segregation ratios were mainly concentrated in two linkage groups of the Ferragnes map.  相似文献   

16.
In microbiology the terms viability and culturability are often equated. However, in recent years the apparently self-contradictory expression viable-but-nonculturable (VBNC) has been applied to cells with various and often poorly defined physiological attributes but which, nonetheless, could not be cultured by methods normally appropriate to the organism concerned. These attributes include apparent cell integrity, the possession of some form of measurable cellular activity and the apparent capacity to regain culturability. We review the evidence relating to putative VBNC cells and stress our view that most of the reports claiming a return to culturability have failed to exclude the regrowth of a limited number of cells which had never lost culturability. We argue that failure to differentiate clearly between use of the terms viability and culturability in an operational versus a conceptual sense is fuelling the current debate, and conclude with a number of proposals that are designed to help clarify the major issues involved. In particular, we suggest an alternative operational terminology that replaces VBNC with expressions that are internally consistent.  相似文献   

17.
The biochemical composition and spatial distribution of particulate organic matter (POM) were studied in the Ross Sea (Antarctica) in summer 1989 to assess the quantitative role of organic carbon fractions in the cycling of organic matter in the water column. Large differences in chemical composition were observed between surface and deep layers. The results indicated that, despite large geographical differences, POM was quite homogeneous, of phytoplankton origin and mostly detrital. Different ratios were used to investigate the changes in biochemical composition of particulate organic matter in relation to the ice-melting: CN (organic carbonorganic nitrogen ratio) and C-POMPOC (sum of carbohydrate, protein and lipid carbontotal organic carbon ratio) were used to analyse the percentage of refractory organic material. PPRTPCHO (proteincarbohydrate ratio) were used to establish POM age and RNADNA ratios as a relative measure of particulate activity; POCChl a and N-PPRTChl a ratios were used to estimate the autotrophic contribution to the suspended particulate organic matter. Despite its low caloric value (5.3 Kcal g POM–1), an high caloric content in the photic layer (1.6 Kcal m–3 of POM and 2.5 Kcal m–3 of POC) was found thus indicating that a large amount of food was available to higher trophic levels.  相似文献   

18.
The fatty acid composition of individual myelin lipids from rat forebrain and spinal cord was analysed at 20 and 30 days p.p. During this phase of rapid myelination the proportions of C 160 and C 180 fatty acids decreased whereas the relative amounts of long chain and unsaturated fatty acids increased in most lipid classes. This developmental shift was more pronounced in the forebrain and was different with respect to both magnitude and direction for each myelin lipid. The experimental induction of chronic hyperphenylalaninaemia (hyper-Phe) from day 3 p.p. lead to alterations in the rate of myelination, which were most pronounced in the forebrain. At 20 days, especially in the forebrain, chain elongation and desaturation of fatty acids were delayed. This delay was maximal in sphingomyelin fatty acids, C 180 and C 241. In hydoxycerebrosides, the shift in the fatty acid composition from C 160 to C 220 was accelerated in hyper-Phe rats. No significant difference in the fatty acid composition of any myelin lipid was found in the more mature myelin (spinal cord, 30 days p.p.). No evidence was found of a primary effect of hyper-Phe on myelination.In memoriam of M. Klapproth who died by a tragic accident.  相似文献   

19.
Summary A stock of Blattella germanica bearing the interchange T(3; 12)/3;12 was subjected to close inbreeding with selection for random disjunction at metaphase I. After 3–4 generations of selection, interchange quadrivalent chiasma frequency decreased, variability in free bivalent chiasma frequency increased sharply, and individuals with either random or directed disjunction were present in the stock. Random disjunction was modified from a ratio of 2112 (adj.-1; alt.-1; adj.-2; alt.-2) to a ratio of 1111. After 7–8 generations of selection, chiasma frequency appeared to stabilize at lower than normal levels and variability decreased for both quadrivalents and free bivalents. Directed disjunction was modified from a ratio of 2114 to 1112, and no individuals with the original high level of directed disjunction were detected. Chains-of-four tended to orient randomly, especially in individuals where the ring quadrivalents showed directed disjunction. Relaxation of inbreeding, but not selection, produced an increase in chiasma frequency and variability in both free bivalents and quadrivalents, but the modified ratios for both random and directed disjunction were retained. These results are discussed with respect to inbreeding effects and genetic control of chiasma frequency and metaphase I disjunction in interchange quadrivalents.  相似文献   

20.
W. Hofmann 《Hydrobiologia》1980,73(1-3):255-258
Keratella cochlearis occurs in many Holstein lakes (northern Germany) as three well defined and separated forms: cochlearis, hispida, and tecta, each showing very little variation between the lakes. The present data show that the tecta form did not originate from a Lauterborn cycle.  相似文献   

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