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991.
Canová NK Kmonícková E Martínek J Zídek Z Farghali H 《Cell biology and toxicology》2007,23(5):337-354
Increased cytosolic calcium ([Ca2+]
i
) and nitric oxide (NO) are suggested to be associated with apoptosis that is a main feature of many liver diseases and is
characterized by biochemical and morphological features. We sought to investigate the events of increase in [Ca2+]
i
and endoplasmic reticulum (ER) calcium depletion by thapsigargin (TG), a selective inhibitor of sarco-ER-Ca2+-ATPases, in relation to NO production and apoptotic and necrotic markers of cell death in primary rat hepatocyte culture.
Cultured hepatocytes were treated with TG (1 and 5 μmol/L) for 0–24 or 24–48 h. NO production and inducible NO synthase (iNOS)
expression were determined as nitrite levels and by iNOS-specific antibody, respectively. Hepatocyte apoptosis was estimated
by caspase-3 activity, cytosolic cytochrome c content and DNA fragmentation, and morphologically using Annexin-V/propidium iodide staining. Hepatocyte viability and mitochondrial
activity were evaluated by ALT leakage and MTT test. Increasing basal [Ca2+]
i
by TG, NO production and apoptotic/necrotic parameters were altered in different ways, depending on TG concentration and
incubation time. During 0–24 h, TG dose-dependently decreased iNOS-mediated spontaneous NO production and simultaneously enhanced
hepatocyte apoptosis. In addition, TG 5 μmol/L produced secondary necrosis. During 24–48 h, TG dose-dependently enhanced basal
NO production and rate of necrosis. TG 5 μmol/L further promoted mitochondrial damage as demonstrated by cytochrome c release. A selective iNOS inhibitor, aminoguanidine, suppressed TG-stimulated NO production and ALT leakage from hepatocytes
after 24–48 h. Our data suggest that the extent of the [Ca2+]
i
increase and the modulation of NO production due to TG treatment contribute to hepatocyte apoptotic and/or necrotic events. 相似文献
992.
Schönswetter P Lachmayer M Lettner C Prehsler D Rechnitzer S Reich DS Sonnleitner M Wagner I Hülber K Schneeweiss GM Trávnícek P Suda J 《Journal of plant research》2007,120(6):721-725
We explored the fine-scale distribution of cytotypes of the mountain plant Senecio carniolicus along an altitudinal transect in the Eastern Alps. Cytotypes showed a statistically significant altitudinal segregation with
diploids exclusively found in the upper part of the transect, whereas diploids and hexaploids co-occurred in the lower range.
Analysis of accompanying plant assemblages revealed significant differences between cytotypes along the entire transect but
not within the lower part only, where both cytotypes co-occur. This suggests the presence of ecological differentiation between
cytotypes with the diploid possessing the broader ecological niche. No tetraploids were detected, indicating the presence
of strong crossing barriers.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
993.
Bjelaković G Beninati S Pavlović D Sokolović D Stojanović I Jevtović T Bjelaković GB Nikolić J Basić J 《Amino acids》2007,33(3):525-529
Summary. Our study was undertaken to elucidate the effects of selenomethionine (SeMet) on polyamine metabolism in regenerating rat
liver tissue, as useful model of rapidly growing normal tissue. We have examined the levels of spermine, spermidine and putrescine
in liver tissue. At the same time we have evaluated the activities of polyamine oxidase (PAO) and diamine oxidase (DAO), the
catabolic enzymes of polyamine metabolism.
The obtained results suggest that polyamine levels in regenerating liver tissue, at 7th day after two-thirds partial hepatectomy, were higher in comparison with control group. The administration of selenomethionine
to hepatectomized animals during seven days, in a single daily dose of 2.5 μg/100 g body weight, increases the amount of spermine
and spermidine; the level of putrescine does not change under the influence of SeMet in regenerating rat liver tissue.
PAO activity is lower in regenerating hepatic tissue than in control group. Supplementation of hepatectomized animals with
SeMet significantly decreases the activity of this enzyme. DAO activity was significantly higher in hepatectomized and in
operated animals treated with SeMet compared to the sham-operated and control ones.
The differential sensitivity observed in our model of highly proliferating normal tissue to SeMet, compared with the reported
anticancer activity of this molecule is discussed. 相似文献
994.
Llorente MT Clavel A Goñi MP Varea M Seral C Becerril R Suarez L Gómez-Lus R 《Parasitology international》2007,56(3):201-205
Several species of Cryptosporidium have been associated with infection. Cryptosporidium parvum and Cryptosporidium hominis are the main agents of cryptosporidiosis in humans. Stool samples from 108 Cryptosporidium-infected patients were submitted to PCR-RFLP analysis for a 553-bp fragment of Cryptosporidium oocyst wall protein (COWP) gene and an 826-864 bp fragment of the small-subunit ribosomal RNA (SSU-rRNA) gene. Ninety-two patients were immunocompetent children and 16 were HIV-infected adults. C. hominis was detected in 69 patients (59 immunocompetent and 10 HIV-infected); C. parvum, in 34 patients (28 immunocompetent and 6 HIV-infected); and C. meleagridis and C. felis in one patient each (both immunocompetent children). Three samples yielded negative results. C. parvum was significantly more frequent in children from rural areas than in those of urban residence (p=0.010). As far as we know, this is the first surveillance study about the molecular characterization of Cryptosporidium in humans performed in Spain. The finding of zoonotic species infecting humans calls for further research on this subject. 相似文献
995.
Growth and reproduction were studied in the laboratory in a cross-designed experimental set-up in four Daphnia galeata subpopulations collected from different locations (with respect to water characteristics) in a reservoir (epilimnion, metalimnion
and hypolimnion in the deepest part of the reservoir near the dam and epilimnion of the upstream part of the reservoir) and
in a laboratory clone of the same species. The results of two-way ANOVA revealed significant effects of the two parameters
manipulated – source of water used for cultures and Daphnia subpopulation – on the life history characteristics of growth and reproduction. The water from the upstream part of the reservoir
was the most favourable culture medium for all characteristics of the Daphnia groups studied (the largest primiparae, clutches and eggs, the shortest postembryonic development time and filtering setae).
The poorest performances were recorded in the downstream, epilimnetic and metalimnetic waters. The primiparae in the hypolimnetic
water were smaller but had relatively larger clutches of smaller eggs and slightly longer postembryonic development times.
The Daphnia subpopulation originating from the hypolimnion had the smallest primiparae, the largest clutches, the smallest eggs and the
shortest postembryonic development, whereas the opposite was found in animals from the epilmnion. These differences in ecologically
relevant traits were supported by analysis of the quasi-neutral genetic markers that indicated significant site-dependent
differences in clonal structure between the subpopulations. There was no consistent trend to higher within-group variance
in the life history traits in the genetically heterogeneous subpopulations from the reservoir compared to the laboratory clone. 相似文献
996.
Dipeptidyl peptidase III (DPP III) is a zinc exopeptidase with an implied role in the mammalian pain-modulatory system owing to its high affinity for enkephalins and localisation in the superficial laminae of the spinal cord dorsal horn. Our study revealed that this human enzyme hydrolyses opioid peptides belonging to three new groups, endomorphins, hemorphins and exorphins. The enzymatic hydrolysis products of endomorphin-1 were separated and quantified by capillary electrophoresis and the kinetic parameters were determined for human DPP III and rat DPP IV. Both peptidases cleave endomorphin-1 at comparable rates, with liberation of the N-terminal Tyr-Pro. This is the first evidence of DPP III acting as an endomorphin-cleaving enzyme. 相似文献
997.
Matej Reberšek Cécile Faurie Maša Kandušer Selma Čorović Justin Teissié Marie-Pierre Rols Damijan Miklavčič 《Biomedical engineering online》2007,6(1):25
Background
Gene electrotransfer is a non-viral method used to transfer genes into living cells by means of high-voltage electric pulses. An exposure of a cell to an adequate amplitude and duration of electric pulses leads to a temporary increase of cell membrane permeability. This phenomenon, termed electroporation or electropermeabilization, allows various otherwise non-permeant molecules, including DNA, to cross the membrane and enter the cell. The aim of our research was to develop and test a new system and protocol that would improve gene electrotransfer by automatic change of electric field direction between electrical pulses. 相似文献998.
Jemec A Drobne D Tisler T Trebse P Ros M Sepcić K 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2007,144(4):303-309
The most commonly used toxicity test worldwide is the acute Daphnia magna test. The relevance of acetylcholinesterase (AChE) and glutathione S-transferase (GST) activity in D. magna exposed to chromium, cadmium, and diazinon was evaluated in connection with this standard test. We found no link between enzyme activities and immobility. Concentrations of Cr(6+) up to 280 microg/L had no effect on AChE and GST activities, while 20% immobility was observed. At concentrations of 20-25 microg/L of Cd(2+) AChE activity was increased by about 50%. The effect of diazinon on both enzymes was insignificant up to concentrations that caused 27% immobility. Consequently, while the use of AChE and GST activities is recommended when the mode of action of chemicals is studied, the value of these biomarkers in routine acute toxicity tests is limited because the relationship between enzyme activities and immobility of D. magna exposed to different chemicals is unclear. 相似文献
999.
Říha Milan Rabaneda-Bueno Ruben Jarić Ivan Souza Allan T. Vejřík Lukáš Draštík Vladislav Blabolil Petr Holubová Michaela Jůza Tomas Gjelland Karl Ø. Rychtecký Pavel Sajdlová Zuzana Kočvara Luboš Tušer Michal Prchalová Marie Seďa Jaromír Peterka Jiří 《Hydrobiologia》2022,849(15):3351-3371
Hydrobiologia - To understand the spatiotemporal overlap in the habitat use of sympatric predators, we studied longitudinal activity and reservoir section and depth use of pike (Esox lucius),... 相似文献
1000.
Yuzhe Zhang Guanglong Li Shaowang Hu Jinfeng Liu Yushi Jiang Siyan Liu Shuyan Guan Jing Qu Dan Yao i Shi Yixuan Liu 《Phyton》2022,91(6):1183-1198
Soybean (Glycine max (L.) Merr.) is an important cultivated crop, which requires much water during its growth, and drought seriously affects soybean yields. Studies have shown that the expression of small heat shock proteins can enhance drought resistance, cold resistance and salt resistance of plants. In this experiment, soybean GmHsps_p23-like gene was successfully cloned by RT-PCR, the protein encoded by the GmHsps_p23-like gene was subjected to bioinformatics analysis, and the pCAMBIA3301-GmHsps_p23-like overexpression vector and pCBSG015-GmHsps_p23-like gene editing vector were constructed. Agrobacterium-mediated method was used to transform soybeans to obtain positive plants. RT-PCR detection, rehydration experiment and drought resistance physiological and biochemical index detection were performed on the T2 generation positive transgenic soybean plants identified by PCR and Southern hybridization. The results showed that the overexpression vector plant GmHsps_p23-like gene expression increased. After rehydration, the transgenic overexpression plants returned to normal growth, and the damage to the plants was low. After drought stress, the SOD and POD activities and the PRO content of the transgenic overexpression plants increased, while the MDA content decreased. The reverse was true for soybean plants with genetically modified editing vectors. The drought resistance of the overexpressed soybeans under drought stress was higher than that of the control group, and had a stronger drought resistance. It showed that the expression of soybean GmHsps_p23-like gene can improve the drought resistance of soybean. The cloning and functional verification of soybean GmHsps_p23-like gene had not been reported yet. This is the first time that PCR technology has been used to amplify the soybean GmHsps_p23-like gene and construct an expression vector for this gene. This research has laid the foundation for transgenic technology to improve plant drought resistance and cultivate new drought-resistant transgenic soybean varieties. 相似文献