Bogdan Doleżych

Effects of nickel exposure and acute pesticide intoxication on acetylcholinesterase, catalase and glutathione S-transferase activity and glucose absorption in the digestive tract of Helix aspersa (Pulmonata, Helicidae).

The activity of detoxifying enzymes and glucose absorption were measured in the digestive tract of Helix aspersa exposed to nickel. Nickel decreased CAT activity and, in the lower concentration, inhibited intestinal absorption of glucose. Elevated AChE activity and unchanged GST activity indicate diversity in enzymatic response to nickel. Nickel at higher concentration, destroying the intestinal wall integrity, caused high glucose influx. Nickel pre-treatment augmented the response to a single diazinon application. AChE activity was greatly reduced compared with nickel-untreated snails. The reduction in CAT activity was similar in both groups. Glucose absorption remained unchanged.

Digestive enzymes activity in larvae of Cameraria ohridella (Lepidoptera: Gracillariidae)

This article presents the activity of carbohydratases and proteases in the midgut of Cameraria ohridella larvae--an oligophagous pest whose preferred feeding is horse chestnuts leaves. Optimal media pH of the assayed enzymes were similar to those of other Lepidopterans. Relatively high amylase activity, as well as maltase and sucrase activities, indicates that starch and sucrose are the main digested saccharides. Trehalase activity was similar to that described in other Lepidopterans. Activities of glycosidases were significantly lower than those of disaccharidases what suggests that neither cellulose nor glycosides are important for C. ohridella. Trypsin is the main endoprotease of this pest. Like in other leaf-eaters carboxypeptidase activity was higher than that of aminopeptidase. The activity of the majority of examined enzymes increased in the following successive pest generations, which could be explained by the decreased nutritional value of older leaves. Probably this phenomenon in hydrolases activity in Cameraria is a nonspecific mechanism present at this stage of co-evolution of the horse chestnut and its pest.

ACETYLCHOLINESTERASE, CATALASE AND GLUTATHIONE S-TRANSFERASE ACTIVITY IN BEET ARMYWORM (SPODOPTERA EXIGUA) EXPOSED TO NICKEL AND/OR DIAZINON

The effect of single and combined action of nickel and pesticide (diazinon) on enzymes activity (glutathione S-transferase, catalase and acetylcholinesterase) in the digestive tract, body wall and fat body as well as basic growth parameters (life span and body mass) of Spodoptera exigua were investigated under laboratory conditions. The experiment was carried out on two nickel treated groups [300 (NiI) and 900 (NiII) mg Ni kg(-1) dry weight of the culture medium] and a control group. The results showed that mortality of caterpillars in NiII group was higher (51.1%) when compare with the controls. The body mass of the caterpillars in the NiI group was higher by 20% than in the control group, and the body mass of the pupae in the NiII group was lower by 22% than in the control group. Exposure to nickel influenced AChE, GST and catalase activity in the body wall (increase up to 66%) and GI tract, while in the fat body the above-mentioned activity remained unchanged. The pesticide application caused a strong, about 70% reduction in AChE activity in GI tract, while in case of GST activity pesticide treatment resulted in multidirectional response depending on the organ. Nickel pre-treatment affects the susceptibility to pesticide, which is manifested in a lower activity of GST and catalase in the fat body (from 26 to 36%), when compare with the other experimental groups.

Digestive enzymes activity in subsequent generations of Cameraria ohridella larvae harvested from horse chestnut trees after treatment with imidacloprid

In the present study we describe the effect of chloronicotinoid pesticide (imidacloprid) on the digestive enzymes activity of the Cameraria ohridella larvae after lasting 1 year sublethal exposure to imidacloprid pesticide. Caterpillars - L4 stage (fourth instar, hyperphagic tissue-feeding phase) - were collected from chemically protected white horse chestnut trees 1 year after imidacloprid treatment, and compared with caterpillars collected from non-treated trees in a previous study. Enzymes activity of α-amylase, disaccharidases, glycosidases and proteases was assayed. The presence of pesticide in ingested food changed the digestive enzymes profile of caterpillars. The analysis of correlations between different digestive enzymes showed many significant correlations (P<0.05) among glycolytic activities like β-glucosidase and α-galactosidase activities. Statistically significant correlations for proteolytic activity were found between trypsin and chymotrypsin activity and aminopeptidase activity that occurred only in the 1st generation. PCA distinguished five primary components with eigenvalues higher than 1, from which the first two explain almost 59% of analyzed results. Surprisingly, in the pesticide treated groups significantly higher activities of sucrase and lactase in relation to control were found. In general, glycosidase (α-glucosidase, β-glucosidase and β-galactosidase) activities showed a similar pattern of activity in different generations. These results contrast with those obtained with control larvae, where significant differences in activities of α-glucosidase, β-glucosidase and β-galactosidase may result from the different quantity and quality food intake by subsequent generations of larvae. No inter-generation differences in total proteolytic activity were observed in treated larvae. The absolute value of total proteolytic activity was higher than that in the control group. The pesticide present in the vascular system of the horse chestnut tree significantly affected some of the digestive enzymes activities and - in consequence - also interrelationships between enzymes, what may affect the food digestion.

Selenium modifies glutathione peroxidase activity and glutathione concentration in mice exposed to ozone-provoked oxidative stress.

The aim of this study was to show the direct effect of selenium on glutathione peroxidase (GSH-Px) activity and GSH/GSSG concentrations in 3- and 6-month-old mice. An ozone-oxygen mixture was used to provoke an oxygen stress. To measure the Se-effect mice were gavaged with sodium selenite. GSH-Px activity and total glutathione concentrations were determined in serum and in the postnuclear fraction of liver and lungs. Additionally glutathione concentrations were determined in whole blood. Both ozone and selenium, administered separately, reduced GSH-Px activity in lungs of 6-month-old animals, while in young mice an opposite effect of Se was observed. Ozone administered jointly with Se did not influence GSH-Px activity in 6-month-old mice, while in young, 3-month-old mice, a stimulatory effect in lungs was observed. There were no significant changes in GSH-Px activity in the liver of 6-month-old mice, but the stimulatory effect occurred in young mice treated with Se and Se & ozone jointly. In young mice, ozone (also ozone with Se) augmented glutathione concentrations. The response to ozone and selenium strictly depended on age and the antagonism between selenium and ozone was observed only in a few cases.

Alteration of carbohydrates metabolism and midgut glucose absorption in Gromphadorhina portentosa after subchronic exposure to imidacloprid and fenitrothion

This study was undertaken to test the hypothesis that following exposure to insecticides, changes take place in the metabolism of carbohydrates and absorption in the midgut of insects. The Madagascar hissing cockroach (Gromphadorhina portentosa) was chosen for the experiment as a model organism, due to it being easy to breed and its relatively large alimentary tract, which was important when preparing the microperfusion midgut bioassay. In each group of cockroaches treated with imidacloprid and fenitrothion, absorption of glucose, expressed as the area under the curve (AUC), was elevated compared to the control group. Glucose in the hemolymph of the examined insects was present in a vestigial amount, often below the threshold of determination, so the determinable carbohydrate indices were: hemolymph trehalose concentration and fat body glycogen content. The level of trehalose found in the hemolymph of insects when exposed to fenitrothion, and irrespective of the level of concentration mixed into food, were significantly lower when comparing to the control samples. Imidacloprid acted analogically with one exception at the concentration of 10 mg·kg−1 dry food where trehalose concentration did not differ from the control values. Coupling with fat body glycogen concentration was less visible and appeared only at the concentrations of 5 and 10 mg imidacloprid·kg−1 dry food. As described in this study changes in the sugar distribution and midgut glucose absorption indicate that insects cover the increased energy needs induced by insecticides; also at the gastrointestinal tract level. The result indicates that the midgut glucose absorption parameters could be considered as a non-specific biomarker of insecticide toxicity.

Within and between seasonal changes of detoxifying capabilities of Cameraria ohridella (Lepidoptera : Gracillariidae) larvae.

Cameraria ohridella is an invasive leaf miner, a severe pest of horse chestnut trees. Chemical control needs recognition of intrinsic metabolic capability to cope with external stressing factors. Our tasks were to check annual effects of generation, and host tree age on detoxifying abilities of the last larval stage. Activities of CAT, SOD, GSTPX, GST CarE and AChE were assayed in the midgut of larvae from two localities during 3 years and three generations, annually. Activities of GSTPX and GST were high, but CAT and SOD were low in relation to other lepidopteran larvae. In general, the second generation larvae had the highest activity, indicating an effective defence against allelochemicals produced by the host. Effects of host tree age were significant for SOD, GSTPX and CarE activities. Significant annual differences on enzyme profiles of CAT, SOD, CarE and AChE reflected differences of temperature and precipitation between consecutive years.

Ileal transposition in rats influenced glucosemetabolism and HSP70 levels

Abstract Objective: Ileal transposition procedure (IT), in combination with sleeve gastrectomy, is widely used to induce diabetes remission and to control related metabolic abnormalities. A transposition of a long segment of distal ileum in obese Zucker rats improved glucose tolerance 6 months after IT. The premise of our study was to to examine the long - term effects of ileum transposition on the liver glycolytic enzymes content in a euglycemic group of operated Zucker rats. Methods: Twenty male Zucker rats underwent either the transposition of 50% distal ileum or a sham surgery. Six months after surgery, liver tissue concentrations of glycogen synthase kinase alpha (GSK-3α), glucose 6-phosphatase (G6PC), glycogen phosphorylase (PYGM) and phosphofructokinase (PFK) and HSP70 were assessed by immunoenzymatic methods. Results: HSP70 values were significantly higher in the IT group compared to SHAM. G6PC liver concentrations in the IT group were almost 1.45-fold lower than in the SHAM operated rats. Statistical analyses (F-test) showed HSP70 levels were significantly related to caveolin-1and SHAM group. Conclusions: Lowered glycolytic enzyme concentrations assessed in the liver suggest positive effects on glucose metabolism in long-term observations.

Assessment of adipokines, adenine nucleotides and uric acid in the dynamics of coronary intervention

Abstract Introduction: The association of vaspin and visfatin, with a myocardial infarction is still not fully understood. Reduced levels of adenine nucleotides are hallmarks of chronic heart failure. There is little data concerning the relationship between these markers and their changes over time. Material/Methods: The concentration of adenine nucleotides, vaspin and visfatinwere assessed in 41 consecutive patients with acute myocardial infarction one before (day I) and four days after (day IV) percutaneous coronary intervention (PCI) and a control group. Results: Visfatin concentrations were higher before and after PCI vs. control (visfatin I: median 25.55, 20.12 - 30.69 ng/ml; visfatin IV: median 20.79, 16.89 - 25.61 ng/ml vs. control: median 14.94, 10.66 - 25.25 ng/ml; p < 0.0001). Vaspin concentrations were lower before and after PCI vs. control (vaspin I: median 0.18, 0.11 - 0.44 ng/ml; vaspin IV: median 0.24, 0.15 - 0.58 ng/ml vs. control: median 1.303, 1.13 - 2.26 ng/ml, p < 0.00001). Concentrations of visfatin, day I, correlated well to vaspin concentrations (r2 = 0.201, p = 0.011). ATP levels were significantly lower in patients vs. controls (day I: p = 0.00012; day IV: p = 0.0001). Conclusions: Changes in the analyzed visfatin and vaspin concentrations can be used as potential MI markers. Visfatin serum concentration may be considered a potential marker to differentiate MI over time.

Metabolic surgery in zucker rats influenced miRNA, caveolin-1 expression and lipid metabolism

Abstract Aims: A transposition of the long segment of distal ileum in obese Zucker rats improved glucose tolerance 6 months after IT. It was undertaken to compare the gene expression of miRNA-103, -107 and caveolin-1 in the liver of euglycemic groups of IT relative to SHAM operated rats. Main methods: Obese, male Zucker rats underwent either transposition of 50% distal ileum or sham surgery. For determining the gene expression, the Real-Time PCR for caveolin-1 and miRNA-103, -107 was performed. Plasma concentrations of LDL, HDL, TG and total cholesterol were measured with enzymatic colorimetric assays after optimization procedure. Key findings: The Cav-1 expression in liver tissue after ileal transposition was 1.22 times higher compared to the SHAM group (SHAM median 63.58, min 41.3, max 82.4; IT median 77.35, min 60.8, max 95.41, p < 0.001). miRNA-107 expression was significantly downregulated by 0.6-fold in the IT group compared to the SHAM group (SHAM median 507.51, min 236.42, max 721.29; IT median 355.2, min 278.15, max 478.15, p < 0.015. The level of TG was significantly higher after IT surgery (SHAM median 115, min 96, max 143; IT median 153, min 115, max 162, p = 0.001). The total cholesterol plasma levels decreased after IT (SHAM median 178, min 161, max 183; IT median 128, min 103, max 114, p < 0.000001). The LDL plasma level in IT was two-fold lower than in the SHAM (SHAM median 117, min 68, max 151; IT median 58, min 45, max 61, p < 0.000001). Significance: The transposition of 50% of the distal ileum lead to an increase in caveolin-1 and reduction in miR-107 expression compared to those of SHAM group. Endogenous miR-107 is more involved in regulation of the functions of insulin-target liver tissue than miRNA-103. Reduced LDL and cholesterol plasma levels suggest positive effects on lipid metabolism in long-term observations. The present study is the first to show a lack of IT effect regarding triglycerides six months after surgery.