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We examined the hypothesis of lower-level processing abnormalities related to perceptual grouping in boys with autism aged 3-6 years. We investigated event-related potentials response to visual elements that either formed perceptually coherent illusory contour or were arranged in a noncoherent way. The results showed that in healthy boys the illusory contour as compared with control stimulus elicited enhanced negativity of N1 peak (C effect), which has been previously found in adults. Autistic boys demonstrated the reliable inverted illusory contour effect, that is, more positive N1 amplitude to illusory contour. We hypothesized that boys with autism were sensitive to difference between illusory contour and control figures basing on collinearity processing mechanisms implemented in neural circuitry of primary visual cortex.

The study presents new data on the structural and functional organization of the mesonephros of the grayling Thymallus thymallus (Linnaeus, 1758). Adult grayling were sampled in the middle course of the Unya River, a tributary of the Pechora River (Komi Republic, Russia). The mesonephros of the grayling, as of other freshwater fishes, is composed by nephrons, blood vessels and hematopoietic tissue forming the renal interstice. In the interstice, сells with a radial vesicle array and chloride cells were discovered; the latter were mostly localized near the renal tubules. The degree of the interstice development in the mesonephros of the grayling was determined. New data on the ultrastructure of leukocytes, cells with a radial vesicle array, chloride cells, and nephron segments were obtained. A lack of mesangial cells, a small number of podocytes, and a thin basement membrane were observed on the sections of a renal corpuscle, being characteristic features of the ultrathin organization of the mesonephros in freshwater members of Salmoniformes and Esociformes. In the grayling’s nephrons, no neck segment was found, which was reported earlier for several species, including mammals. On the sections of proximal tubules, the ciliated cells were rare, and large amounts of the tubular-vesicular network in the zone of endocytosis of the type II epithelial cells were observed. On the sections of distal tubules, short blade-shaped cytoplasmic processes, with large numbers of invaginations of cytoplasmic membrane, were found. On the basis of the distinctive ultrastructure features mentioned above, the inference that grayling show the cytological markers of adaptation to euryhalinity was made. Thus, the results contribute to the knowledge of mesonephros development in fishes during their life history. From the species protection standpoint, our study provides baseline data on a WBC differential in the mesonephros as well as superoxide dismutase, catalase, glutathione S-transferase, and ethoxyresorufin-O-deethylase activities, which can be used in further studies addressing the health status of grayling populations.

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Alternation of physiological states during the annual cycle (pre-spawning mobilization, spawning energy loss, post-spawning accumulation of energy reserve, declined metabolic activity during the wintering) occurring in the wide temperature range requires high plasticity of fish defense systems. The article presents a 2-year study of hepatic antioxidant defenses and lipid peroxidation in the temperate cyprinid fish, common bream Abramis brama (L.), in relation to basic annual rhythms, such as photoperiodic and temperature cycling, reproduction and feeding activity. The objective of the study was to evaluate the plasticity of antioxidant defenses in bream under normal conditions throughout the annual cycle, by measuring hepatic antioxidants (superoxide dismutase, catalase, glutathione-S-transferase activities and reduced glutathione concentrations) and products of lipid peroxidation (thiobarbituric acid reactive substances concentrations). The results suggested that hepatic levels of antioxidants in bream varied dramatically during the annual cycle allowing bream to develop necessary adaptation and implement reproduction program. The lowest values of all studied antioxidants were witnessed in the middle of winter. In early spring, antioxidant enzyme activities increased rapidly reaching their maxima in late spring and summer. Toward the end of autumn, enzyme activities were declining toward the levels observed before the ice breakup. Spring-summer up-regulation of antioxidant defenses along with increased lipid peroxidation indicated bream to be experiencing mild oxidative stress.

The breams living in five regions of the Rybinsk Reservoir with different degrees of anthropogenic load have been assayed for the characteristics of their antioxidant system (AOS) and lipid peroxidation (LPO) system. Individuals caught at two stations in the Rybinsk Reservoir that maximally differ in the degree of pol lution display different qualitative and quantitative compositions of polychlorinated biphenyls (PCBs). At the station at the Sheksninskii Reach, which is located near a local source of pollution (Cherepovets), the total content of PCBs and homologous groups of congeners is one order of magnitude higher than in the bream living at the station of the comparatively clean Molozhskii Reach. The AOS response and the generation intensity of LPO products in the bream (Abramis brama L.) liver caused by different degrees of anthropogenic pollution have been determined. The content of LPO products in the liver of the breams caught in the Shek sninskii Reach is considerably higher and the values of AOS characteristics are considerably lower than in the fish from the Molozhskii Reach. The bream living in the Molozhskii and Volzhskii Reaches are in a more favorable state than those in the Sheksninskii Reach. The AOS and LPO characteristics are an appropriate biomarker for estimating the state of the health of the fish.

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