Chlorophyll (Chl) fluorescence technique was ušed to monitor Cu damage in photosynthetic process in intact leaves of a Cu-tolerant {Silene conipacla) and a non- Cu-tolerant {Thlaspi ochroleucum) species. The initial fluorescence level (Fq) increased whereas the variable fluorescence (Fy) decreased in T. ochroleucum under low and high Cu-dose, suggesting injuries both in reaction centie level and in photooxidizing side of photosystem 2 (PS2). The photochemistiy activity of PS2, Fy/Fp, revealed a slight increase under 8 pM Cu in both species, while at 160 pM of Cu a strong inhibition in T. ochroleucum was observed. The Fp/F() ratio appeared to increase under low Cu dose, however the high Cu dose in nutrient solution resulted in damage to the thylakoid structure affecting the PS2 donor and acceptor side, mainly in T. ochroleucum. The slow part of the Chl fluorescence induction cuiwe was affected more by Cu stress, than the fast one. At low Cu concentration the Rfd value increased in S. compacla but decreased in T. ochroleucum. Fligh Cu dose induced an almost complete inhibition of this parameter, that was more severe in the non-tolerant plants. Yet, low Cu dose enhanced the Chl content in S. compacla but on exposure to 160 pM Cu the symptoms of chlorosis were more visible in T. ochroleucum. Thus, excess of Cu has direct negative effects on the photosynthetic electron transport that may be accounted for by the destruction of the photosynthetic pigments.
Water availability is a major limiting factor in desert ecosystems. However, a winter snowfall role in the growth of biological soil crusts is still less investigated. Here, four snow treatments were designed to evaluate the effects of snow depth on photosynthesis and physiological characteristics of biological soil crusts. Results showed that snow strongly affected the chlorophyll fluorescence properties. The increased snow depth led to increased contents of photosynthetic pigments and soluble proteins. However, all biological soil crusts also exhibited a decline in malondialdehyde and soluble sugar contents as snow increased. Results demonstrated that different biological soil crusts exhibited different responses to snow depth treatment due to differences in their morphological characteristics and microhabitat. In addition, interspecies differentiation in response to snow depth treatment might affect the survival of some biological soil crusts. Further, this influence might lead to changes in the structural composition and functional communities of biological soil crusts., R. Hui, R. M. Zhao, L. C. Liu, Y. X. Li, H. T. Yang, Y. L. Wang, M. Xie, X. Q. Wang., and Obsahuje bibliografii
Quantitative and qualitative changes of serum proteins, apart from glycation, have not been sufficiently studied in streptozotocin-induced diabetic rats (D), the most common experimental model for diabetes. Thus, we decided to analyze the serum of diabetic rats by concanavalin A-blotting in comparison with rats with acute inflammation induced by fermented yeast (Y), in which characteristic alterations of serum proteins have been described. Two months after the streptozotocin treatment, the blood glucose levels were highly elevated (456± 24 vs. 124± 10 mg/dl, p<0.001, n=12), the body weight was significantly lower than normal (279± 10 vs. 392± 6 g, p<0.001, n=12), and serum proteins appeared to be highly glycated (p<0.001) when analyzed by the fructosamine assay, without any significant change in the total serum protein concentration. Analysis by concanavalin A-blotting, revealed a significant decrease of a1-inhibitor-3 (a1-I3, p<0.05) and an increase of the b chain of haptoglobin (b-Hp, p<0.05) in both D and Y rats (n=3) compared with control animals. However, acute inflammation caused a marked rise of two prominent acute phase proteins, a2-macroglobulin and hemopexin, which did not change appreciably in diabetic rats. Further work will be necessary to evaluate the physiopathological significance of these phenomena which could result from changes of both concentration and glycosylation of the aforementioned proteins., L. Saso, P. Tommasino, G. Italiano, E. Grippa, M.G. Leone, M.T. Gatto, B. Silvestrini., and Obsahuje bibliografii
Specific neuronal populations are known to express calcium binding proteins (CBP) such as calbindin (CB), parvalbumin (PV) and calretinin (CR). These CBP can act as calcium buffers that modify spatiotemporal characteristics of intracellular calcium transients and affect calcium homeostasis in neurons. It was recently shown that changes in neuronal CBP expression can have significant modulatory effect on synaptic transmission. Spinothalamic tract (STT) neurons form a major nociceptive pathway and they become sensitized after peripheral inflammation. In our experiments, expression of CBP in STT neurons was studied in a model of unilateral acute knee joint arthritis in rats. Altogether 377, 374 and 358 STT neurons in the segments L3-4 were evaluated for the presence of CB, PV and CR. On the contralateral (control) side 11 %, 9 % and 47 % of the retrogradely labeled STT ne urons expressed CB, PV and CR, respectively. On the ipsilateral (arthritic) side there was significantly more CB (23 %) and PV (25 %) expressing STT neurons, while the number of CR positive neurons (50 %) did not differ. Our results show increased expression of fast (CB) and slow (PV) calcium binding proteins in STT neurons after induction of experimental arthritis. This suggests that change in CBP expression could have a significant effect on calcium homeostasis and possibly modulation of synaptic activity in STT neurons., D. Sojka, G. Zacharova, D. Spicarova, J. Palecek., and Obsahuje bibliografii
Ozone depletion leads to an increase in UV rays of solar radiation reaching the surface of the Earth which is harmful to biological systems. Of the eye, the cornea is directly open to increased amount of UV rays of which mainly UVB rays are capable to induce reactive oxygen species damaging the cells. Previous studies showed that the irradiation of the cornea with UVB rays leads to morphological as well as metabolic disturbances of the cornea. Also, corneal hydration and corneal light absorption are increased after UVB rays. These changes were observed after five days of repeated irradiation of the cornea with UVB rays. The aim of the present paper was to examine how early the changes of corneal hydration and light absorption occur after UVB irradiation. The rabbit corneas were irradiated with UVB rays for one, two, three or four days. Corneal light absorption was examined spectrophotometrically and corneal hydration measured by pachymeter (as corneal thickness). Results show that changes of corneal hydration and light absorption appear early after UVB irradiation and increase along with the number of irradiations. In conclusion, irradiation of the rabbit cornea with UVB rays leads to harmful changes of its optical properties., Č. Čejka ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Photosynthesis in iron-deficient soybean and maize leaves decreased drastically. The quantum yield of photosystem 2 (PS2) electron transport (ΦPS2), the efficiency of excitation energy capture by open PS2 reaction centres (Fv'/Fm'), and photochemical quenching coefficient (qP) under high irradiance were lowered significantly by iron deficiency, but non-photochemical quenching (NPQ) increased markedly. The analysis of the polyphasic rise of fluorescence transient showed that iron depletion induced a pronounced K step both in soybean and maize leaves. The maximal quantum yield of PS2 photochemistry (Φpo) decreased only slightly, however, the efficiency with which a trapped exciton can move an electron into the electron transport chain further than QA (Ψ0) and the quantum yield of electron transport beyond QA (ΨEo) in iron deficient leaves decreased more significantly compared with that in control. Thus not only the donor side but also the acceptor of PS2 was probably damaged in iron deficient soybean and maize leaves. and Chuang-Dao Jiang, Hui-Yuan Gao, Qi Zou.
In children and adolescents (250 healthy subjects) serum dopamine-beta-hydroxylase (DBH) activity (23.95.2 to 57.117.5 μmol/min/ml) increases with the age between 3-10 years, later it decreases approximately by the age of 10-14 years. At the age of 21 to 60 years DBH level is stable. Our study described decreasing DBH activity in adolescents at the age of 10-14 years in the studied sample of healthy persons. Experimental animals (200 Wistar rats, 5-120 days old) show the same trend of enzymatic activity, similarly as in humans. DBH activity in rats is between 0.850.1 to 2.80.05 μmol/min/ml. This activity is highest in 5-day-old rats; it decreases till the age of 14 days and increases mainly in 14- to 35-day-old animals. Decrease of DBH activity in rats between 35 to 40 days is significant and corresponds to the reduction of DBH activity in adolescent humans (10-14 years). Adult rats (aged 90-120 days) show a stable DBH activity. DBH activity intermediately decreases in 10- to 14-year-old children. This decrease corresponds to the intermediate developmental changes of electrophysiological parameters (decreasing EEG activity in healthy adolescents occurs in 10-14 years old children). Puberty is coupled with intermediate decreasing of DBH activity in man and also in experimental animals in the period of prominent psychological and physiological changes.
The purpose of the study was to check whether hypoxia of corneal tissue increases the collagenolytic activity due to release of reactive oxygen and nitrogen species. Rats were exposed to hypoxia 10 % O2 for 4, 14, and 21 days. The radical tissue injury was measured by the level of nitrotyrosine and changes in the lipoperoxide-related fluorophores. Collagen protein composition was analyzed by slab gel electrophoresis. The activity of gelatinolytic enzymes was studied using the zymography. The vascularization of the corneas was measured. We found no differences in the corneal tissue in the gel electrophoretic profile of collagenous proteins and gelatinolytic activity between normoxic and hypoxic rats. We did not find any sign of radical tissue injury. There were no changes in the vascularization of corneas after exposition to hypoxia. The environmental 10 % hypoxia does not induce radical tissue injury and an increase of collagenolytic activity in the rat cornea., G. Mahelková, J. Korynta, A. Moravová, J. Novotná, R. Vytášek, J. Wilhelm., and Obsahuje bibliografii a bibliografické odkazy
Three diffusion parameters of nervous tissue, extracellular space (ECS) volume fraction (λ), tortuosity (α) and non-specific uptake (k’) of tetramethylammonium (TMA + ), were studied in the spinal cord of rats during experimental autoimmune encephalomyelitis (EAE). The three parameters were determined in vivo from concentration-time profiles of TMA+ using ion-selective microelectrodes. EAE was induced by injection of guinea-pig myelin basic protein (MBP), which resulted in typical morphological changes in the CNS tissue, namely inflammatory reaction, astrogliosis, blood-brain barrier (BBB) damage and paralysis. EAE was accompanied by a statistically significant increase of a (mean±S.E.M.) in the dorsal horn from 0.21±0.01 to 0.28±0.02, in the intermediate region from 0.22±0.01 to 0.33±0.02, in the ventral horn from 0.23±0.01 to 0.47±0.02 and in white matter from 0.18±0.03 to 0.30±0.03. There were significant decreases in tortuosity in the dorsal horn and in the intermediate region and decreases in non-specific uptake in the intermediate region and in the ventral horn. Although the inflammatory reaction and the astrogliosis preceded and greatly outlasted the neurological symptoms, the BBB damage had a similar time course. Moreover, there was a close correlation between the changes in extracellular space diffusion parameters and the manifestation of neurological signs. We suggest that the expansion of the extracellular space alters the diffusion properties in the spinal cord. This may affect synaptic as well as non-synaptic transmission, intercellular communication and recovery from acute EAE, and may contribute to the manifestation of neurological signs in EAE rats.
a1_Gastric lipase (GL) plays an important role in emulsification and digestion of food fat. Lipids are components of the hydrophobic mucus and mucosa barrier. Damage of the gastric mucosa may therefore be related to changes in the lipid content and GL activity. In the present paper, we studied the effect of administration of a single dose of 96 % ethanol (E) and indomethacin 20 mg.kg-1 (IND) on the activity of GL and on the concentrations of nonesterified fatty acids (NEFA) and triacylglycerols (TG) in the gastric mucosa of rats. Furthermore, we studied how these changes are affected by allopurinol (ALO), pentoxifylline (PX) and L-DOPA pretreatment 30 min before administration of E or IND. The effect of sialoadenectomy (SA) on these parameters was also evaluated. We found: 1) significant (p<0.01) inhibition of GL activity after administration of E and IND and also ALO, as well as after pretreatment with ALO before E and PX before IND. L-DOPA administered alone stimulated GL activity, but its administration before IND significantly (p<0.01) inhibited this enzymatic activity. GL activity was decreased to the threshold values in SA rats and after administration of E to SA animals. 2) NEFA concentrations were decreased after E and increased significantly (p<0.01) after IND administration. A marked significant (p<0.01) decrease in NEFA was found after PX and L-DOPA administration. The administration of ALO also lowered the concentration of NEFA. Pretreatment by drugs before E and IND resulted in a significant increase of NEFA in comparison with the drugs given alone (p<0.05 for ALO + E; p<0.01 for PX + IND). 3) TG were also decreased in all experimental groups in comparison with the control group, i.e. after E and IND, after ALO and SA and also after pretreatment by ALO before E. The concentration of TG decreased after PX, significantly (p<0.05) after L-DOPA and after pretreatment by PX before IND., a2_Pretreatment by ALO before E and L-DOPA before IND resulted in the increase of TG in comparison with drugs alone. Thus, these results suggest certain protective effect of pretreatment with ALO, PX and L-DOPA against the E- and IND-induced decrease in NEFA and TG during injury of the gastric mucosa. On the other hand, inhibition of GL activity was also apparent after administration of these drugs before E and IND, which suggest presence of a persisting impairment of lipid digestion in the stomach., A. Sedláková, A. Kohút, M. Šarišský., and Obsahuje bibliografii