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471.
Summary Fluorescence histochemical examination of biogenic amines of the frog esophageal mucosa revealed that a serotonin-like monoamine exhibiting an yellow fluorescence was present in a certain type of cells. The new type of cells was specifically stained by the immunohistochemical method using anti-serotonin antiserum. From these observations, it is suggested that the new cell type in the esophageal mucosa probably contains 5-hydroxytryptamine (serotonin). The serotonin-containing cells were argentaffin, but negative for Grimelius' silver stain. 相似文献
472.
Rhabditis axei, the free living nematode, was detected in the faeces of a chicken maintained in a clean cage in the parasitology laboratory, Zagazig University, Egypt. The source of these worms and the method of their transmission to the laboratory was discussed. The experimental inoculation of 3 chickens with R. axei demonstrated that their survival after passing through the intestine was not possible. Free living nematodes could be confused easily with Strongyloides sp. during routine faecal examination. 相似文献
473.
Lubomír Floch Juraj Kubán Andrea Gogová Peter Zálupsky Tibor Jakubík Nada Prónayová 《Molecules and cells》1992,1(10):175-180
Triton B catalyzed Michael addition of nitromethane on esters of α,β-unsaturated acids 1 has been studied. The course and regioselectivity of the reaction is discussed in the view of structure of products 2a-g, 3a-g, 4g, f, 5g, f, assessed by GC/MS, NMR and IR spectroscopy and by MOPAC 6 (AM1) calculations, respectively. 相似文献
474.
Philip W. Landfield Olivier Thibault Mary L. Mazzanti Nada M. Porter D. Steven Kerr 《Developmental neurobiology》1992,23(9):1247-1260
This paper reviews evidence that brain aging and Alzheimer's disease (AD) are somehow closely related and that the hippocampus (CA1) is highly vulnerable to cell loss under both conditions. In addition, two current lines of evidence on the mechanisms of hippocampal cell loss with aging are considered, including studies of neuronal calcium dysregulation and studies of cumulative glucocorticoid (GC) neurotoxicity. Moreover, recent electro-physiological studies have shown that excess glucocorticoid activation of hippocampal neurons increases the influx of calcium through voltage-activated calcium channels. Second messenger systems may mediate the steroid modulation of calcium channels. Therefore, it is hypothesized that excess glucocorticoid activation and neuronal calcium dysregulation may be two phases of a single process that increases the susceptibility of neurons to neurodegeneration during aging and Alzheimer's disease. © 1992 John Wiley & Sons, Inc. 相似文献
475.
Barbara Vilhar Maja Ravnikar Milan Schara Marjana Nemec Nada Gogala 《Plant cell reports》1991,10(11):541-544
Summary Jasmonic acid (JA) and its derivatives are a novel group of plant endogenous growth regulators. In our experiments some new data about the physiological effects of JA were obtained using electron paramagnetic resonance spectroscopy. Experiments were performed on potato plants (Solanum tuberosum L. cv. Vesna) grown in vitro. Different quantities of JA (0.1–10 M) were added to the growth medium. Root samples of plants grown on media supplemented with JA showed a more rapid spin probe N-oxyl-2,2,6,6-tetramethyl piperidine reduction than the control plants, which is a possible indicator of altered root permeability. Samples of leaf protoplasts were probed with methyl ester of 5-doxyl-haxadecanoic acid. We observed a membrane fluidity decrease in protoplasts isolated from plants grown on higher concentrations of JA (1 and 10 M).Abbreviations JA
jasmonic acid
- Me-JA
methyl jasmonate
- EPR
electron paramagnetic resonance
- RubisCO
ribulose-1,5-biphosphate carboxylase/oxigenase
- MeFASL(10,3)
methyl ester of 5-doxyl-hexadecanoic acid
- MES
(2(N-morpholino)ethanesulfonic acid)
- TEMPO
N-oxyl-2,2,6,6-tetramethyl piperidine 相似文献
476.
Temperature-Sensitive Mutants of Adenovirus Type 12 Defective in Viral DNA Synthesis 总被引:11,自引:10,他引:1
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Nada Ledinko 《Journal of virology》1974,14(3):457-468
Ten temperature-sensitive (ts) mutants of adenovirus type 12 which produce plaques at 31 but not at 38.5 C have been isolated after mutagenesis with nitrosoguanidine or nitrous acid. The mutants have been classified into six separate complementation groups. DNA-DNA hybridizations have shown that at 38.5 C the ts 401 and 406 mutants of groups B and E, respectively, synthesized less than 10% of the normal level of viral DNA. The two mutants were also defective in the production of late proteins at the nonpermissive temperature, as shown by fluorescent-antibody tests and analysis by sodium dodecyl sulfatepolyacrylamide gel electrophoresis. Genetic recombination between the ts viruses 401 and 406 has been demonstrated; the recombination frequency for the wild-type virus production was 17.7%. Both mutants induced an increase in thymidine kinase activity at 38.5 C. Moreover, the two viral DNA-defective mutants shut off host DNA synthesis at the restrictive temperature. It is striking that at 38.5 C ts virus 401 transformed two to eight times more hamster cells than the wild-type virus, whereas ts virus 406 transformed at a frequency similar to the wild-type virus. 相似文献
477.
478.
Hosny Abdel Aziz Mohamed Sharaf Magdy Omar Ahmed Abou El-Yazied Nada Ibrahim AlJwaizea Shaimaa Ismail Mohamed M. A. Omar Khadiga Alharbi Amr Elkelish Moataz Tawfik 《Phyton》2023,92(4):1019-1036
Drought stress has become more common in recent years as a result of climate change impacts on the production
of banana crops and other fruit trees. The growth and productivity of Musa spp are severely impacted by the gradual degradation of water resources and the erratic distribution pattern of annual precipitation amount. The aim
of the work includes increased drought tolerance in light of water scarcity in the world as a result of the bananas’
being gluttonous for water needs. This investigation was carried out from 2019 to 2020 to study the effect of
potassium silicate on morphological growth and biochemical parameters of Musa acuminata L under drought
stress by PEG. As a result, drought stress reduced the morphological characteristics such as shoots number, shoot
length, roots number, and survival percentage and biochemical characteristics such as chlorophyll a, b, carotenoids, stomatal status, and RWC. While proline content increased in the leaf of M. acuminata L. Media complemented with K2SiO3 (2 to 6 mM) either individually or in combination with PEG led to an improvement in all
morphological and biochemical characteristics. The activities of CAT, POD, and PPO enzymes increased signifi-
cantly compared to control. Furthermore, the lowest PPO, CAT, and POD activity were achieved. Additionally,
K2SiO3 treatments under drought stress successfully enhanced the leaf stomatal behavior. Our results suggest that
K2SiO3 can help to maintain plant integrity in the tested cultivar under drought stress. 相似文献
479.
Prof. Gokhan Zengin Ass. Prof. Nada M. Mostafa Dr. Yasmin M. Abdelkhalek Prof. Omayma A. Eldahshan 《化学与生物多样性》2023,20(9):e202300117
Rhoifolin (apigenin-7-O-β-neohesperidoside) belongs to the class of flavonoids and was reported to exhibit anti-inflammatory, cytotoxic, antidiabetic, hepatoprotective, and cardioprotective activities. The current study presents the in-vitro evaluation of the antioxidative effects of rhoifolin by many assays, namely DPPH, CUPRAC, ABTS, phosphomolybdenum, and FRAP. Enzyme inhibitory potential was also evaluated for acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, amylase, and glucosidase enzymes. While results revealed weak antioxidant activities for rhoifolin, the compound demonstrated some promising enzyme inhibitory effects against BChE (4.03 mg GALAE/g) and tyrosinase (7.44 mg KAE/g) but was not active on AChE. Regarding anti-diabetic enzymes, the compound was active on amylase but did not show any inhibition effect on glucosidase. In-silico molecular docking study was performed for rhoifolin on the active site of NADPH oxidase, BChE, and amylase enzymes to verify the observed enzyme inhibitory effect. Good binding affinities were observed for rhoifolin on all the docked enzymes, revealing numerous hydrogen bonds, carbon-hydrogen, van der Waals interactions. This is the first study to evaluate the enzyme inhibition potential of rhoifolin. We concluded that the increase in the degree of glycosylation might decrease the antioxidant abilities of flavonoids and that rhoifolin had moderate enzyme inhibition abilities to be investigated in future studies. 相似文献
480.
Alicja Jaworska Nada Stojcevic-lemic Anthony H. W. Nias H. Sies 《Free radical research》1993,18(3):139-145
The activities of reactive oxygen species scavenging enzymes, superoxide dismutases (SODs) and catalase (in cells of two melanomas (mouse B16 and human SK23) and in Chinese hamster ovary (CHO) cells were examined. Melanoma cells are relatively depleted in activities of superoxide dismutases and catalase as compared to CHO cells. Short equitoxic (500μM for CHO and B16 cells and 5 μM for SK23 cells) paraquat treatment (15 min before the X-irradiation, 45 min in postirradiation period - the total time of treatment was 1 h) caused an increase in radiation resistance, measured as colony forming ability, in two of the three lines examined.
It is proposed that PQ may exert its radioprotective effect by induction of antioxidant enzymes. 相似文献
It is proposed that PQ may exert its radioprotective effect by induction of antioxidant enzymes. 相似文献