Seminal plasma (SP) proteins are responsible for sperm functional quality. Developing a reliable method to determine the degree of oxidative damage of these proteins is important for establishing semen fertilizing ability. The main aim of the study was to verify the applicability of protein carbonyl derivatives measurement in the SP of canine and stallion, using a method with 2,4-dinitrophenylhydrazine (DNPH). The research material consisted of ejaculates obtained from eight English Springer Spaniels, and from seven half-blood stallions during the breeding and non-breeding season. The content of carbonyl groups in the SP was measured on the basis of the reactions with DNPH. The following reagent variants were used to dissolve protein precipitates: Variant 1 (V1) – 6M Guanidine solution and Variant 2 (V2) – 0.1M NaOH solution. It has been shown that to obtain reliable results for the measurement of protein carbonylated groups in the dog and horse SP, both 6M Guanidine and 0.1M NaOH may be used. A correlation was also found between the number of carbonyl groups and the total protein content in the canine (V1: r = -0.724; V2: r = -0.847) and stallion (V1: r = -0.336; V2: r = -0.334) SP. Additionally, the study showed a higher content (p≤0.05) of protein carbonyl groups in the stallion SP in the non-breeding season compared to the breeding season. The method based on the reaction with DNPH, due to its simplicity and cost effectiveness, appears to be suitable for large-scale application in the determination of the SP proteins oxidative damage in dog and horse semen.

In this study, we examined whether and to what extent oxidative stress is induced in seedlings of two winter triticale (Triticosecale Wittm.) varieties (susceptible Tornado and resistant Witon) in response to infestation by the cereal grain aphid (Sitobion avenae L.) and bird-cherry-oat aphid (Rhopalosiphum padi L.). We compared the level of hydrogen peroxide (H2O2) and lipid peroxidation products as well as markers of protein damage (protein-bound thiol and carbonyl groups). The studied parameters were measured at 6, 24, 48 and 96 h post-initial aphid infestation compared to the non-infested control seedlings. Our studies indicated that the cereal aphid feeding evoked oxidative stress in the triticale seedlings. Cereal aphid feeding increased the H2O2 level in triticale tissues, with maximum levels observed at 24 and 48 h post-infestation. Triticale infestation with aphids also increased lipid peroxidation products in triticale seedlings, with the maximal levels at 48 or 96 h post-infestation. Further, there was a reduction in protein thiol content and an increase in protein carbonyl content in the triticale seedlings after infestation with female aphids. Stronger triticale macromolecule damages were evoked by the oligophagous aphid R. padi. There was a more substantial protein thiol content reduction in the resistant Witon cultivar and higher accumulation of protein-bound carbonyls in the tissues of the susceptible Tornado cultivar. The changes were proportional to the aphid population and the time of aphid attack. These findings indicate that the defensive strategies against cereal aphid (S. avenae and R. padi) infestation were stimulated in triticale Tornado and Witon seedlings. Our results explain some aspects and broaden the current knowledge of regulatory mechanisms in plant-aphid interactions.