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  • Author or Editor: Sylwia Goławska x
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Effects of some dietary o -dihydroxyphenols on biochemical markers of oxidative stress within tissues of Sitobion avenae (Fabricius), (Homoptera, Aphididae) and Rhopalosiphum padi (Linnaeus), (Homoptera, Aphididae) has been studied. Among the studied aphid morphs the highest concentration of total thiols, hydrogen peroxide and lipid peroxidation products (TBARS) was noted for winged adults (alatae). Higher content of H 2 O 2 was observed within tissues of the oligophagous species R. padi while the monophagous species S. avenae had higher TBARS and total thiols concentration. Aphids exposed the dietary pro-oxidative o -dihydroxyphenols (quercetin, caffeic acid, chlorogenic acid) demonstrated significantly lower concentration of total sulfhydryls and higher level of TBARS and H 2 O 2 than the control ones. Among the studied compounds, chlorogenic acid showed the strongest effect on the level of thiols and TBARS while caffeic acid caused the highest accumulation of the hydrogen peroxide within the aphid tissues.

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Acta Biologica Hungarica
Authors: Iwona Sprawka, Sylwia Goławska, A. Goławski, P. Czerniewicz, and H. Sytykiewicz

The insecticidal activity of plant lectins against a wide range of insect species have been intensively studied. Understanding the mechanism of the toxicity of lectins is one of the studied aspects. In the present research, the first step was determine the effect of phytohemagglutinin (PHA) on the development, fecundity and mortality of grain aphid. Next, the effect of PHA lectin on the activity of such enzymes as: α- and β-glucosidases, alkaline (AkP) and acid (AcP) phosphatases, aminopeptidase N and cathepsin L involved in the metabolism of sugar, phosphorus and proteins of an adult apterae aphids was investigated. The PHA lectin added into the liquid diet increased the pre-reproductive period, mortality of Sitobion avenae, the time of generation development and decreased its fecundity and the intrinsic rate of natural increase. In addition, activity of α-glucosidase, alkaline phosphatase and aminopeptidase N of adult apterae exposed to PHA were reduced. The results indicate that the insecticidal activity of PHA on S. avenae may involve changes in activity of the enzymes in the midgut and it may be part of its toxicity.

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Acta Biologica Hungarica
Authors: H. Sytykiewicz, P. Czerniewicz, Iwona Sprawka, Sylwia Goławska, G. Chrzanowski, and B. Leszczyński

The objectives of this study were to elucidate the impact of bird cherry-oat aphid (Rhopalosiphum padi L.) feeding on functioning of the proteolytic machinery in bird cherry leaves. Biochemical analyses proved that R. padi feeding in tissues of primary host stimulated activity of the two major fractions of proteinases (extracted at the optimal pH values: 5.0 and 7.0). Additionally, it has been demonstrated that aphids’ feeding on bird cherry led to a decline in levels of albumins and globulins (main protein fractions in P. padus leaves). The opposite tendency, regarding the amounts of these protein fractions was ascertained at the phase of disappearance of R. padi population on tested shoots. Furthermore, it is reported that an increase in activity of the analysed enzymes and a decline in the content of tested protein fractions, were proportional to density of aphid individuals developing on P. padus side shoots. It is hypothesized that long-term R. padi feeding may lead to intensifying the catabolic processing of proteins by the activated proteolytic machinery in bird cherry leaves. The multi-level biological functions of endogenous plant proteinases and their significance in triggering the defense reactions in aphid-infested plant tissues are discussed.

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