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41.
The effect of pteridine derivatives and analogues on the cell outgrowth from the ovarian explants of the waxmoth, Galleria mellonella, was examined in hanging-drop cultures and cytochemical tests were made for succinate and glucose-6-phosphate dehydrogenases. Most of the derivatives and analogues of 2-amino-4-hydroxypteridine injured to a lesser or greater extent insect ovarian tissues in vitro, depending on the drug structure and the concentration applied. Of all the pteridine derivatives and analogues tested only 2-amino-4-mercaptopteridine and its C-6,7-dimethyl derivative (10 μM) promoted cell outgrowth from the explants as did folate. 相似文献
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Stanislaw Kowalczyk Anna Jakubowska Elbieta Zieliska Robert S. Bandurski 《Physiologia plantarum》2003,119(2):165-174
1- O -(indole-3-acetyl)- β - d -glucose: myo -inositol indoleacetyl transferase (IA- myo -inositol synthase) is an important enzyme in IAA metabolism. This enzyme catalyses the transfer of the indole acetyl (IA) moiety from 1- O -(indole-3-acetyl)- β - d -glucose to myo -inositol to form IA- myo- inositol and glucose. IA- myo -inositol synthase was purified to an electrophoretically homogenous state from maize liquid endosperm by fractionation with ammonium sulphate, anion-exchange, adsorption on hydroxylapatite, affinity chromatography on ConA-Sepharose, preparative PAGE and isoelectric focusing. We thus obtained two enzyme preparations which differ in their R f on 8% polyacrylamide gel. The preparation of R f 0.36 contained a single 56.4 kDa polypeptide, whereas the preparation of R f 0.39 consisted of two polypeptides of 56.4 and 53.5 kDa. Both purified preparations of IAInos synthase also exhibited the activity of an IAInos hydrolase, showing that the dual activity was associated with a single protein. Results of gel filtration and analytical SDS-PAGE suggest that the native enzyme exists as both a monomeric (65 kDa) and homo- or heterodimeric form (110–130 kDa). Analysis of peptide maps and amino acid sequences of two 21 amino-acid peptides showed that polypeptides of 56.4 and 53.5 kDa have the same primary structure and that the 3 kDa difference in molecular mass is probably caused by different glycosylation levels. Comparison of this partial and internal amino acid sequence with sequences of other plant acyltransferases indicated similarity to several proteins which belonged to the serine carboxypeptidase-like (SCPL) acyltransferase family. 相似文献
46.
The fraction of free fatty acids (FFA) is present in skeletal muscles. However, there is almost no data regarding regulation in the content of this intramuscular lipid pool. We took advantage of the isolated muscle preparation to examine whether: a) increasing exogenous concentration of FFA (500microM or 700microM, 30min) b) insulin (10.00 I.U./L, 30min), c) adrenalin (4.4 nM, 30 min), or d) contractions (200ms, tetani, 1Hz, 30min), affect the FFA content inside myocytes. Incubation of soleus (S) and extensor digitorum longus (EDL) with increasing concentrations of exogenous FFA (from 500microM to 700microM) resulted in an increase in the total FFA fraction in both muscles studied (by 280.2% and 259.1%, respectively). In contracting muscles FFA pool was significantly reduced both in S (by 73.1%) and in EDL (by 31.1%). Neither stimulation by adrenalin nor insulin affected the total content of FFA fraction in the muscles examined. We conclude that a) increased availability of exogenous FFA at the sarcolemma level results in an increase in the size of intramuscular FFA fraction b) the intracellular FFA fraction is utilized by contracting muscles with regard to the fiber composition and to a greater extent in more oxidative muscles, c) FFA fraction remains stable upon stimulation by insulin or adrenalin. 相似文献
47.
The course of acute infection of mice with ts mutant or the native strain DNA and the antigens of HSV in brain nerve cells were determined. Virus DNA was detected in brains of all mice in both animal groups while the virus antigens--only in cells of mice infected with the native strain. It can be suggested, therefore, that the ability of ts mutant to replicate in central nervous system of the infected mice is lacking or much lower. The detection of virus nucleic acid 3-5 months after virus infection might indicate a possibility of establishing latent infection. However, ts mutant showed a significantly lower possibility of latency induction, as compared with highly virulent strains. It was found that the mutant ability to induce latent infection was markedly increased when mice were treated with both ts mutant and Depo-Medrol as immunosuppressive agent. This finding shows both a possibility of increase of frequency of latent infections in the state of immunosuppression, and of activation of the latent infection (recurrence of acute form of infection). 相似文献
48.
The study was undertaken to investigate the ability of enterococci to assimilate iron via siderophores of bacteria living in the same habitats in the human organism. The potential recipients of exogenous siderophores were six Enterococcus faecalis and six Enterococcus faecium strains, isolated from clinical materials of human origin. The donors of siderophores were Gram-negative rods (various species of the Enterobacteriaceae, Pseudomonas and Acinetobacter) and Gram-positive cocci (various species of Staphylococcus and Streptococcus). All of the investigated E. faecium and only two E. faecalis strains demonstrated the ability to utilize the siderophores of the aforementioned bacterial groups, predominantly the chelators of Gram-negative rods, those of Gram-positive cocci were utilized to a smaller extent. Four recipient strains from E. faecalis species did not demonstrate the ability to utilize siderophores synthesized by all of 40 investigated donor strains. 相似文献
49.
Halińska, A. and Lewak, St. 1987. Free and conjugated gibberellins in dormancy and germination of apple seeds.
The presence of gibberellin A4 (GA4 ) was confirmed in partly stratified seeds of apple ( Malus domestica Borb., cv. Antonówka) by mass spectrometry of the methyl ester. Levels of free and conjugated gibberellins A4+7 and A9 changed during drying of mature seeds, during cold and warm stratification, as well as during germination of dormant and non-dormant embryos. The temporary rise in GA4+7 during cold stratification and during the culture of dormant embryos as well as the lack of it under conditions of warm stratification, allowed us to postulate a role for GA4+7 in the removal of dormancy. In addition, GA9 was absent in dormant embryos and increased during cold stratification and during the culture of non-dormant embryos. This suggests the involvement of GA9 , in induction of normal development of the seedling. The equivalence between changes in free and conjugated GAs suggests that formation and hydrolysis of conjugates are involved in the control of the physiologically active levels of free GA4+7 and GA9 . 相似文献
The presence of gibberellin A
50.