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1.
Histochemical method for dipeptidyl aminopeptidase II with a new anthraquinonyl hydrazide substrate.
A Dikov M Dimitrova T Pajpanova R Krieg K J Halbhuber 《Cellular and molecular biology, including cyto-enzymology》2000,46(7):1213-1218
A new method for the histochemical visualization of lysosomal aminopeptidase dipeptidyl peptidase II activity (DPP II) is developed. The substrate L-Lys-L-Ala-5-chloro-1-anthraquinonylhydrazide-2HBr (Lys-Ala-CAH) is readily hydrolyzed by the enzyme to release 5-Cl-1-anthraquinonylhydrazine (CAH). The last compound is simultaneously coupled to an aromatic aldehyde, e.g. 4-nitrobenzaldehyde (p-NBA) or piperonal (3,4-methylenedioxybenzaldehyde; PPL), to form a highly insoluble deeply colored hydrazone, marking the enzyme locations. Using the new method, DPP II is successfully localyzed in tissue sections from different rat organs. 相似文献
2.
E Schulte N A Dimitrova G V Dimitrov G Rau C Disselhorst-Klug 《Journal of electromyography and kinesiology》2005,15(3):290-299
Changes in muscle fibre length and surface electrode position with respect to the muscle fibres affect the amplitude and frequency characteristics of surface electromyography (SEMG) in different ways. Knowledge of changes in muscle fibre length would help towards a better interpretation of the signals. The possibility of estimating the length through SEMG during voluntary contractions was checked in this study. The fibres' semi-length was estimated from the product of the conduction velocity and conduction time during which the wave of excitation propagated from the end-plate region to the ends of the fibres. Short (10 s), moderate (30% of maximum voluntary contraction) isometric contractions were performed by 10 subjects at different elbow joint angles (80-140 degrees in steps of 20 degrees ). Monopolar signals were detected non-invasively, using a two-dimensional electrode array. High spatial resolution EMG and a decomposition technique were utilised to extract single motor unit activities for triggered averaging and to estimate conduction velocity. A significant increase with joint angle was found in conduction time and estimated fibre semi-length. Changes in conduction velocity with joint angle were found to be not significant. The methodology described allows the relative changes in fibres' semi-length to be estimated from SEMG data. 相似文献
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Phenolic acids were separated into three fractions and determined by HPLC inMedicago sativa callus culture at the age of two, three and four weeks. The contents of free and especially of predominating ester-bound
phenolic acids decreased with callus age to approx. 80 % while the content of phenolic acids nonextractable by methanol increased
byca. 90 %. The proportion of benzoic acid derivatives rose from 15 to 21 % within four weeks. The determined difference in the
contents of phenolic acids in the upper and lower parts of callus diminished with age. The content of bound forms was higher
in the lower part regardless of the callus age. The content of free acids in two weeks old callus was half as high as in the
upper part. 相似文献
5.
Milena Riesová-Kučerová 《Biologia Plantarum》1969,11(5):338-346
The dependence of the frequency of recessive lethal (two groups), chlorophyll and morphological mutations on the mutagen concentration was determined in M2 after subjection to N-nitroso-N-methylurea applied to seeds ofArabidopsis in three concentrations (0·05, 0·10 and 0·20mm). The observed frequencies were compared with the theoretically expected ones for the linear and for two exponential types of dependence, by using the t-test, according to the formulas m=k. C, m=k. C3/2, m=k. C2. No satisfactory agreement with any expected type of dependence was found when directly observed frequencies were used. Since a considerable deficit of mutation frequency was observed in high concentrations, the correction of frequency values was done with respect to the probability of occurence of double mutations. After such a correction, a clear exponential relation was found in both types of lethals and a linear one in chlorophyll and morphological mutations. The probable occurence of multiple mutations should be, therefore, taken into account if the dependence of mutation frequency on the concentration of mutagen is discussed. 相似文献
6.
Changes in the radioresistance of bacteria after the inhibition of proteosynthesis in the preirradiation phase 总被引:2,自引:1,他引:1
The strain ofEscherichia coli WP2 (tryv) was irradiated with UV light, at a dosage of 240 erg/mm. Proteosynthesis was inhibited by the elimination of the essential
amino acid from the cultivation medium. Changes in radioresistance were followed during 45 minutes of starvation and during
the subsequent 45 minutes of restitution after the addition of the essential amino acid. The radioresistance of the cells
showed a linear increase immediately after the removal of the essential amino acids, proportional to the duration of the inhibition
of proteosynthesis. The increase in radioresistance was shown to be reversible. After the addition of the essential amino
acid there was an immediate decrease in radioresistance which was most marked in the first 15 minutes. 相似文献
7.
Fabrizio Villani Milena Galimberti Elena Monti Francesco Piccinini Enrica Lanza Annalinda Rozza Luigia Favalli Paola Poggi Franco Zunino 《Free radical research》1990,11(1):145-151
The effects of two sulfhydryl compounds, glutathione (GSH) and N-acetylcysteine (NAC), on the cardiotoxicity of doxorubicin (DXR) were tested on in vitro and in vivo models. DXR was administered to rats as 4 weekly i.v. doses of 3mg/kg. GSH (1.5 mmoles/kg), given i.v. 10 min before and 1 hr after DXR, was found to prevent the development of the delayed cardiotoxic effects of DXR, as assessed by electrocardiographic and mechanical parameters, as well as by histological examination of left ventricular preparations. In contrast, equimolar oral doses of NAC (1 hr before and 2hrs after DXR) were found to be ineffective. Both GSH and NAC prevented the negative inotropic effect produced by DXR on isolated rat atria. A good correlation exists between the cardioprotective effects of the two agents and their ability to enhance the non-protein sulfhydryl group content of the myocardium. Differences observed in vivo between GSH and NAC might be accounted for by pharmacokinetic factors. 相似文献
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Milena Rychnovská-Soudková 《Biologia Plantarum》1963,5(2):175-180
Jedním z kritérií pro posuzování odolnosti rostiin v??i suchu je jejich schopnost sná?et vodní deficit ani? nastanou irreversibilní změny v jejich pletivech. Tato schopnost byla zkoumána metodikou, popsanou v p?edlo?ené práci. Listy některých xerothermních trav (druhy roduStipa, Melica atd.) vysýchaly za p?esně definovaných pokusných podmínek tak, ?e dosáhly r?zně odstupňovaného vodního deficitu. Potom byly roz?ezány na segmenty a ve speciálním ráme?ku dosycovány vodou. P?vodní deficit i jeho vyronání bylo sledvváno váhově. Výsledné hodnoty byly znázorněny graficky. Zatímco ztráta vody z list? během vysýchání probíhala v některých p?ípadech lineárně, k?ivka dosycování ukazovala charakteristický zlom, který indikoval, jak dalece byla ztráta vody nahraditelná, a kdy do?lo ji? k irreversibilním změnám. Ukázalo se, ?e ze studované série rostlin druhy typicky kontinentální mají schopnost doplňovat svou zásobu vody ad integrum i p?i zna?ném vodním deficitu. Rostliny s areálem spí? oceánického charakteru tuto schopnost nemají. Je pravděpodobné, ?e i tato vlastnost bude směrodatná p?i výkladu kausální fytogeografie. 相似文献
10.