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21.
Eszter Szász Fanni Sarkadi Eszter Szöllősi Renáta Kopena János Török Balázs Rosivall 《Journal of evolutionary biology》2023,36(1):156-168
Brood sex ratios (BSRs) have often been found to be nonrandom in respect of parental and environmental quality, and many hypotheses suggest that nonrandom sex ratios can be adaptive. To specifically test the adaptive value of biased BSRs, it is crucial to disentangle the consequences of BSR and maternal effects. In multiparous species, this requires cross-fostering experiments where foster parents rear offspring originating from multiple broods, and where the interactive effect of original and manipulated BSR on fitness components is tested. To our knowledge, our study on collared flycatchers (Ficedula albicollis) is the first that meets these requirements. In this species, where BSRs had previously been shown to be related to parental characteristics, we altered the original BSR of the parents shortly after hatching by cross-fostering nestlings among trios of broods and examined the effects on growth, mortality and recruitment of the nestlings. We found that original and experimental BSR, as well as the interaction of the two, were unrelated to the fitness components considered. Nestling growth was related only to background variables, namely brood size and hatching rank. Nestling mortality was related only to hatching asynchrony. Our results therefore do not support that the observed BSRs are adaptive in our study population. However, we cannot exclude the possibility of direct effects of experimentally altered BSRs on parental fitness, which should be evaluated in the future. In addition, studies similar to ours are required on various species to get a clearer picture of the adaptive value of nonrandom BSRs. 相似文献
22.
Esterase zymograms were obtained following polyacrylamide slab gel electrophoresis of protein extractsFusarium sambucinum and related species originating from different geographic locations and different matrices. The sites of esterase activity were recorded, and the Rfs were calculated. The data were used for the construction of phenograms by cluster analysis and nonlinear mapping by computerized classification techniques. The fifteen isolates ofF. sambucinum, the eight isolates ofF. torulosum and the six isolates ofF. spec. nov. each had identical profiles, and are therefore electrophoretically distinct species. The isolates ofF. sarcochroum, one ofF. sambucinum sensu lato (BBA 64280) and fifteen isolates ofF. sambucinum were electrophoretically indistinguishable from each other. We assume they are synonymous. The isolate ofF. bactridioides, one ofF. sambucinum sensu lato (BBA 64993) and eight isolates ofF. torulosum had uniform EST patterns, therefore the two species are electrophoretically identical. We assume they are also synonymous. The remaining three isolates ofF. sambucinum sensu lato are somewhat closely related toF. sambucinum isolates on the basis of our investigations. 相似文献
23.
Dr. Daniel Szöllösi 《Cell and tissue research》1978,191(1):115-119
Summary In polyovular, primordial follicles in the rabbit, desmosomes are found between apposing oocyte surfaces. Morphologically these desmosomes correspond closely to those described in epithelia of vertebrates. The desmosomes alternate with other junctions which are probably gap junctions.This work was supported in part by the G.R.S.T. Grant n 75.7.1313 相似文献
24.
P Baráth I Strausz E Kékes A Szántó 《Acta physiologica Academiae Scientiarum Hungaricae》1979,53(3):311-322
The regional decrease of the speed and extent of the contraction and the relaxation of the canine myocardium induced by coronary ligation was enhanced by intravenously administered nitroglycerin (GTN), simultaneously with the decrease of the left ventricular pressure, while the increase of myocardial fiber length caused by that procedure was partly abolished. The above changes could be reproduced by GTN applied directly onto the ischaemic myocardial surface even before the decrease of the left ventricular pressure. These changes induced by GTN might play a role in the decrease or abolishment of regional asynergic wall motion. 相似文献
25.
In inside-out human red cell membrane vesicles /IOV/, in the absence of Mg2+, the only calcium-induced labelling by γ32P-ATP occurs in a 140–150 000 molecular weight protein fraction, representing the hydroxylamine-sensitive phosphorylated intermediate /EP/ of the calcium pump. In the presence of Mg2+ calcium-induced phosphorylation is accelerated but several other membrane proteins are also phosphorylated through protein kinase action forming hydroxylamine-insensitive bonds. Addition of calmodulin accelerates EP formation both in the absence and presence of Mg2+.Treatment of the membrane with SH-group reagents significantly reduces EP formation. Mild trypsin digestion of IOVs, stimulating active calcium transport, eliminates calmodulin action and decreases the steady-state level of EP. In trypsin-digested IOVs the molecular weight of the 32P-labelled EP is shifted to lower values /110–120 000/ We suggest that trypsin digestion cleaves off a 20–40 000 molecular weight calmodulin-binding regulatory subunit of the calcium pump molecule. 相似文献
26.
The apical cell of the locust testis: an ultrastructural study 总被引:1,自引:0,他引:1
27.
Interaction of phospholipids with proteins, peptides and amino acids. New advances 1987-1989 总被引:1,自引:0,他引:1
1. The review deals with the recent achievements in the study of the various interactions of phospholipids with proteins, peptides and amino acids. The interactions are classified according to the hydrophobic, hydrophilic or mixed character of the interactive forces. The effect of the interaction on the structure and biological activity of the interacting biomolecules is discussed. 相似文献
28.
B Vincze I Pályi D Daubner T Kremmer I Számel I Bodrogi J Sugár J Sepr?di I Mez? I Teplán 《The Journal of steroid biochemistry and molecular biology》1991,38(2):119-126
The specific binding of luteinizing hormone-releasing hormone (LH-RH) agonist in estradiol-dependent MCF-7 and estradiol-independent MDA-MB-231 human breast cancer cells has been studied using [3H]Ovurelin [(D-3H-Phe6),des-Gly10-LH-RH- ethylamide]. The results of Scatchard analyses suggest the presence of a single class of receptor sites, both in cell suspensions and membrane fractions. Evaluation of these peptide receptors appears to reflect additional characteristics of biological behaviour of these human breast cancer cells. The synthetic LH-RH agonist Ovurelin [(D-Phe6),des-Gly10-LH-RH-ethylamide] can directly interfere (25-30%) with the proliferation of MDA-MB-231 human breast cancer cells in culture. The inhibitory effect of Ovurelin in vitro was negligible in the MCF-7 cell line. In the in vivo experiments the treated immunosuppressed mice bearing either MCF-7 or MDA-MB-231 xenografts responded to the high-dose LH-RH analogue Zoladex depot and Decapeptyl depot therapy. Since the MDA-MB-231 tumour was found to be ER-negative it seems possible that the regression of this xenograft results from the direct antitumor action of the LH-RH agonist. 相似文献
29.
Hospitalized geriatric patients (N = 354) from an iodine-deficient area were screened with sensitive thyrotropin (TSH), free and total thyroxine (FT4, T4) and total triiodothyronine (T3) to determine the occurrence rate of clinical and subclinical thyroid dysfunction. The diagnostic value of the tests was compared to each other and to that of the thyrotropin-releasing-hormone test (TRH-test) in order to find the optimal first line screening test in geriatric patients. Clinical hyperthyroidism was found in 13, subclinical hyperthyroidism in 10, overt hypothyroidism in 6 and subclinical hypothyroidism in 8 cases. 20.6% of the patients were euthyroid but had subnormal TSH response to TRH, as a sign of possible thyroid autonomy. The low occurrence rate of clinical thyroid disorders (4.8%) does not justify the screening of geriatric patients in general, but the high probability of thyroid autonomy makes reasonable the investigation of every geriatric patient before iodine administration. Suppressed basal TSH and high FT4 were found to be both sensitive and specific in diagnosing clinical hyperthyroidism, but the predictive value was insufficient; elevated T4 and T3 are specific, but not sensitive. Basal TSH is sensitive, specific and has a good predictive value in diagnosing euthyroidism, whereas normal T4, FT4 or T3 are not specific enough for euthyroidism. Basal TSH is better as a first line test of thyroid function than FT4. A normal basal TSH confirms euthyroidism by itself. Other tests (TRH test, T4, FT4, T3) are necessary to elucidate the clinical importance of a subnormal or suppressed basal TSH. 相似文献
30.
Small doses of β-endorphin (10?11?10?5M) decrease corticosterone production of zona fasciculata cells but fail to influence steroid production of zona glomerulosa cells. 10?4M β-endorphin increases corticosterone production of both zones. The stimulating effect of ACTH on zona fasciculata corticosterone- and zona glomerulosa aldosterone production was decreased by β-endorphin (10?9?10?7M). Conclusion: β-endorphin might modulate both basal and ACTH stimulated corticosterone secretion. 相似文献