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1.
Ouabain-insensitive salt and water movements in duck red cells. II. Norepinephrine stimulation of sodium plus potassium cotransport 总被引:11,自引:9,他引:2
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Catecholamines induce net salt and water movements in duck red cells incubated in isotonic solutions. The rate of this response is approximately three times greater than a comparable effect observed in 400 mosmol hypertonic solutions in the absence of hormone (W.F. Schmidt and T. J. McManus. 1977 a.J. Gen. Physiol. 70:59-79. Otherwise, these two systems share a great many similarities. In both cases, net water and salt movements have a marked dependence on external cation concentrations, are sensitive to furosemide and insensitive to ouabain, and allow the substitution of rubidium for external potassium. In the presence of ouabain, but the absence of external potassium (or rubidium), a furosemide-sensitive net extrusion of sodium against a large electrochemical gradient can be demonstrated. When norepinephrine-treated cells are incubated with ouabain and sufficient external sodium, the furosemide-sensitive, unidirectional influxes of both sodium and rubidium are half- maximally saturated at similar rubidium concentrations; with saturating external rubidium, the same fluxes are half-maximal at comparable levels of external sodium. In the absence of sodium, a catecholamine-stimulated, furosemide-sensitive influx of rubidium persists. In the absence of rubidium, a similar but smaller component of sodium influx can be seen. We interpret these results in terms of a cotransport model for sodium plus potassium which is activated by hypertonicity or norepinephrine. When either ion is absent from the incubation medium, the system promotes an exchange-diffusion type of movement of the co-ion into the cells. In the absence of external potassium, net movement of potassium out of the cell leads to a coupled extrusion of sodium against its electrochemical gradient. 相似文献
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Rafal Krela Elzbieta Poreba Martyna Weglewska Tomasz Skrzypczak Krzysztof Lesniewicz 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(3):521-527
Background
During standard gene cloning, the recombinant protein appearing in bacteria as the result of expression leakage very often inhibits cell proliferation leading to blocking of the cloning procedure. Although different approaches can reduce transgene basal expression, the recombinant proteins, which even in trace amounts inhibit bacterial growth, can completely prevent the cloning process.Methods
Working to solve the problem of DNase II-like cDNA cloning, we developed a novel cloning approach. The method is based on separate cloning of the 5′ and 3′ fragments of target cDNA into a vector in such a way that the short Multiple Cloning Site insertion remaining between both fragments changes the reading frame and prevents translation of mRNA arising as a result of promoter leakage. Subsequently, to get the vector with full, uninterrupted Open Reading Frame, the Multiple Cloning Site insertion is removed by in vitro restriction/ligation reactions, utilizing the unique restriction site present in native cDNA.Results
Using this designed method, we cloned a coding sequence of AcDNase II that is extremely toxic for bacteria cells. Then, we demonstrated the usefulness of the construct prepared in this way for overexpression of AcDNase II in eukaryotic cells.Conclusions
The designed method allows cloning of toxic protein coding sequences that cannot be cloned by standard methods.General significance
Cloning of cDNAs encoding toxic proteins is still a troublesome problem that hinders the progress of numerous studies. The method described here is a convenient solution to cloning problems that are common in research on toxic proteins. 相似文献4.
The objective of this study was to assess the LIF (leukemia inhibitory factor) concentration in uterine flushing and serum (ELISA) of women with proven fertility, infertile women and women with recurrent miscarriage. In addition, progesterone level was determined in serum. A decreased production of LIF in the uterine microenvironment was found in states of impaired fertility. With a cut-off point of 8.23 pg/ml for LIF level in uterine flushings we have achieved 86.7% sensitivity and 100% specificity in detection of women with idiopathic infertility compared to fertile controls. No correlation between LIF in serum and uterine flushing was demonstrated, rendering LIF measurements in serum useless for diagnosis of impaired infertility. We conclude that LIF measurement in uterine flushing could be a useful diagnostic tool to predict unsuccessful implantation. 相似文献
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Malgorzata Szczepańska Przemyslaw Wirstlein Jana Skrzypczak Pawe? P Jagodziński 《Reproductive biology and endocrinology : RB&E》2012,10(1):1
Background
A decrease in HOXA11 expression in eutopic mid-secretory endometrium has been found in women with endometriosis-associated infertility. 相似文献6.
7.
Enhanced production of the pharmaceutically important polyphenolic compounds in Vitex agnus castus L. shoot cultures by precursor feeding strategy
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Ewa Skrzypczak‐Pietraszek Kamil Piska Jacek Pietraszek 《Engineering in Life Science》2018,18(5):287-297
Agitated Vitex agnus castus L. shoot cultures were established to analyse the content of selected pharmaceutically important flavonoids and phenolic acids. Two variants (selected from nine ones) of MS medium were prepared: A (BAP 1 mg/L; NAA 0.5 mg/L; GA3 0.25 mg/L) and B (BAP 2 mg/L; NAA 0.5 mg/L). The biomass was harvested after 1, 2, 3,4, 5 and 6 weeks. Four‐week cultures (variant A) were selected to perform the precursor feeding experiment. The L‐phenylalanine dose of 1.6 g/L appears to be the most advantageous. Compared to the control cultures, the content of the individual compounds increased in a range from 1.4 to 17.3‐fold (e.g. p‐coumaric acid – 17.3 fold; casticin – 4.8‐fold). The biomass from in vitro cultures is richer in neochlorogenic acid (16‐fold), p‐coumaric acid (5.3‐fold), rutin (2.8‐fold), caffeic acid (1.5‐fold) and cinaroside (1.5‐fold) than the leaves of its parent greenhouse‐cultivated plants. Extracts contained 30 mg/100 g DW of casticin, but after the hydrolysis its amount increased up to 200 mg/100 g DW and twice exceeded the content in the greenhouse leaves. The results indicate that V. agnus castus agitated shoot cultures might be considered as a potential biotechnological source of some pharmaceutically important compounds, especially casticin, rutin, neochlorogenic and p‐coumaric acids. 相似文献
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Herosimczyk A Lepczyński A Dratwa-Chałupnik A Kurpińska A Klonowska A Skrzypczak WF 《Folia biologica》2011,59(1-2):25-30
The aim of this study was to determine the influence of age and ingested food (colostrum and mature milk) on the concentrations of selected blood biochemical components connected with nitrogen and mineral metabolism in dairy calves during their first week of life. The experiment was carried out on 13 Polish Black and White breed dairy calves. The animals were fed colostrum within the first 3 days of postnatal life and thereafter the mature milk of their dams until the end ofthe experiment (7 days). The obtained results showed that intensive catabolic and anabolic changes in nitrogen occur in the first week of life. These changes were particularly intense during the first 24-48 hours of life and may reflect dynamic tissue remodelling. The results of this experiment also show that healthy calves efficiently regulate water and electrolyte homeostasis. 相似文献
9.
Mikołajczyk M Skrzypczak J Wirstlein P 《Folia histochemica et cytobiologica / Polish Academy of Sciences, Polish Histochemical and Cytochemical Society》2011,49(4):615-621
Implantation depends on two factors - embryo and endometrium. The period of maximal endometrial receptivity is a poorly understood phenomenon. We decided to look at three possible markers of implantation: pinopodes, leukemia inhibitory factor, and matrix metalloproteinase 2 and their correlations. We included in the study 23 idiopathic infertility patients and 21 patients with recurrent spontaneous abortions of unknown etiology. Twenty one fertile patients were also recruited. A biopsy was used for endometrial dating according to the Noyes and Hertig criteria, and assessed for the presence of pinopodes via a scanning electron microscope. Endometria were examined in Real Time-Polymerase Chain Reaction cycles for the mRNA expression of leukemia inhibitory factor (LIF) and matrix metalloproteinase 2 (MMP2). No difference was found in the stage of pinopodes development, nor in the coverage of endometrial surface between the studied groups. The expression level for LIF mRNA was lower in control patients compared to idiopathic infertility and recurrent miscarriage patients. No difference was detected in the expression of MMP2 between all studied groups. No correlation was found between pinopodes development stage and LIF and MMP2 expressions in endometrium. Of the studied factors, LIF and pinopodes show the most promise as potential markers of endometrial receptivity. However, the results achieved suggest that these markers are independent of each other. 相似文献
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Karolina Nowicka-Bauer Małgorzata Ozgo Adam Lepczynski Marzena Kamieniczna Agnieszka Malcher Wiesław Skrzypczak Maciej Kurpisz 《Reproductive biology》2018,18(2):151-160
The aim of this study was to identify and analyse human sperm proteins from normozoospermic men using 2-dimensional electrophoresis (2-DE) and mass spectrometry (MS). We identified 73 different sperm proteins, including two less characterized human sperm proteins, Annexin A7 (ANXA7) and c14orf105. Bioinformatic analysis of detected sperm proteins revealed new carbohydrate and lipid metabolic pathways, which supply energy to motile sperm. A comparison of our data with available mRNA microarray data from the human testis allows for validation of identified sperm proteins and aids in the recognition of their physiological pathways. 相似文献