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Том 478, № 1 (2018)

Physiology

Sharpening of the Signal Spectrum Contrast as a Result of Lateral Suppression in the Human Auditory System

Supin A., Nechaev D., Popov V., Sysueva E.

Аннотация

The spectrum contrast threshold for the comb-filtered signal was measured at various ripple densities in listeners with normal hearing. The lowest spectrum contrast thresholds of less than 0.1 appeared at a ripple density of 3–4 oct–1. With the ripple density falling down to 1 oct–1, the threshold increased to 0.17. At the ripple density higher than 4 oct–1, the threshold was also growing to achieve 1.0 at a density of 7–8 oct–1. An increase of threshold at high ripple densities can be explained by integration within critical bands. At low ripple densities, the threshold increase may be a result of the lateral suppression that led to sharpening of the spectral contrast.

Doklady Biological Sciences. 2018;478(1):1-4
pages 1-4 views

General Biology

On the Modes of the Formation of the Exoskeleton in Early Jawless Vertebrates (Osteostraci, Agnatha)

Afanassieva O.

Аннотация

Based on recently obtained original and published data on the fine structure of the external skeleton of osteostracan agnathans (Osteostraci, Agnatha), possible modes of the formation of their hard cover in the course of the horizontal growth of the exoskeleton are characterized. The developmental models for the formation of various configurations of cephalothoracic shields typical for osteostracans are revealed. It is shown that, in the morphogenesis of the hard cover of this group of early vertebrates, a significant part of the variants of the exoskeleton horizontal growth characteristic of early vertebrates are observed.

Doklady Biological Sciences. 2018;478(1):5-7
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A New Stem Placental Mammal from the Early Cretaceous of Mongolia

Lopatin A., Averianov A.

Аннотация

A new taxon of stem placentals, Hovurlestes noyon gen. et sp. nov. from the Early Cretaceous of Mongolia (Höovör locality) is described. The new taxon differs from members of the genus Prokennalestes from Höovör in the single-rooted canine and the presence of cusp e, which is an enhancing interlocking between anterior molars (m1 and m2). Hovurlestes noyon gen. et sp. nov. is one of the rarest mammal taxa from Höovör, which expands morphological diversity of the earliest Eutheria.

Doklady Biological Sciences. 2018;478(1):8-11
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Comparative Study of Pygidial Organization in Polychaetes of the Families Nephtyidae and Syllidae

Starunov V., Zaitseva O.

Аннотация

The first comparative study of the polychaete pygidial region has been performed using confocal scanning microscopy and immunohistochemical methods. Fundamentally new data has been obtained on the pygidial organization in representatives the Nephtyidae and Syllidae families. Despite differences in the overall morphology of pygidium, it is characterized by a certain structural plan as a whole that can be the basis for that of all polychaetes. Some insignificant differences in the pygidial structure can be either species-specific or consequences of mutations and seem to have no fundamental importance for the general organization.

Doklady Biological Sciences. 2018;478(1):12-15
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Molar Microwear of Narrow-Headed Vole (Microtus gregalis Pall., 1779) Depending on the Feed Abrasiveness

Zykov S., Kropacheva Y., Smirnov N., Dimitrova Y.

Аннотация

In the narrow-headed vole, enamel microwear of the first mandibular molar (of the protoconid and entoconid anterior enamel wall) was studied under the laboratory conditions and at the fixed feed composition. The classic parameters and the area of the enamel prism lesion were taken into account. The enamel lesion patterns caused by the tooth–tooth and tooth–food interactions have been determined. Differences were found between the voles kept on feed with different abrasive properties, as well as between the lingual and buccal conids of the first mandibular molar. In the Microtus species, the ratio of micro-lesions (pits and scratches) did not depend on the abrasive properties of the feed consumed. The extent of preservation of the enamel contour anterior edge depended on the feed composition and could be used as an indicator for indirect evaluation of the Microtus species diet.

Doklady Biological Sciences. 2018;478(1):16-18
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Influence of the Male Axillary Extracts on Regulation of Menstrual Cycles in Women

Voznessenskaya V., Laktionova T.

Аннотация

The effect of male axillary extract on the length and regularity of the menstrual cycle in women was studied in a long-term experiment (9 months). The male secret extract had no statistically significant influence on the menstrual cycle duration in the reproductive-age women (21–45 years) with normal (26–32 days) and regular cycles or in women with abnormally short (<26 days) cycles. In the group of the reproductive-age women with irregular and abnormally long (>32 days) cycles, as well as in the group of the premenopauseage women (46–51 years) with irregular cycles, the secret extract caused a significant shortening of the menstrual cycle as compared to the control. The effect was preserved for at least two months after the exposure completed.

Doklady Biological Sciences. 2018;478(1):19-21
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Protonephridial Excretory System in Vestimentifera (Siboglinidae, Annelida)

Rimskaya-Korsakova N., Karaseva N., Temereva E., Malakhov V.

Аннотация

Ultrastructural study of the excretory tree of vestimentifera Ridgeia piscesae has shown that it consists of tubules that are blind at their distal ends. The tubules are lined with ciliated cells and have one or two multiciliated terminal cell(s) at the distal ends. In the tubule walls, there are putative ultrafiltration sites. The excretory tree tubules are interpreted as the secondary protonephridia.

Doklady Biological Sciences. 2018;478(1):22-25
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Morphogenetic Effects of Resettlement of Mole Voles (Ellobius talpinus Pall., 1770) from the Southern Population to the Northern Boundary of the Species Range

Vasil’ev A., Bol’shakov V., Vasil’eva I., Evdokimov N., Sineva N.

Аннотация

Geometric morphometry has been used to reveal transformations of mandible morphogenesis in the offspring of mole voles resettled to the northern part of the species range from a southern population. The transformations were new compared to both the original (southern) and the aboriginal (northern) populations. A significant increase in the intragroup morphological disparity estimated by the mean nearest neighbor distance (MNND) in the resettled animals compared to both aboriginal populations is an indirect indication of an increased developmental instability in the resettled animals exposed to new climatic conditions.

Doklady Biological Sciences. 2018;478(1):26-28
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Soft Bottom Communities in Marine Lakes Sisjajarvi and Linjalampi (Barents Sea)

Deart Y., Pereladov M., Spiridonov V., Antokhina T., Rzhavsky A., Britayev T.

Аннотация

Based on the data of benthic surveys of 2010–2012, three benthic communities: a shallow-water community with the dominance of Scoloplos spp., Nucula tennuis, and Scalibregma inflatum; a deep-water community with the dominance of Chaetosone sp.; and a community of mixed sediments, have been distinguished in soft sediments in marine lakes Sisjajarvi and Linjalampi. These communities are typically marine and similar to other communities in shallow areas of the Barents Sea. They mostly differ in a high abundance of the polychaete Scalibregma inflatum and a small number of echinoderms from the communities in other bays of the Barents Sea. The abundance of the polychaete S. inflatum indicates indirectly possible cases of anoxia in Lake Sisjajarvi.

Doklady Biological Sciences. 2018;478(1):29-32
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The Priming of Potato Plants Induced by Brassinosteroids Reduces Oxidative Stress and Increases Salt Tolerance

Efimova M., Khripach V., Boyko E., Malofii M., Kolomeichuk L., Murgan O., Vidershpun A., Mukhamatdinova E., Kuznetsov V.

Аннотация

This is the first study to show that brief pretreatment of potato plants with two brassinosteroids differing in structure causes in plants the ability to react to delayed salt stress by accumulation of compounds with antioxidant activity and by increased salt tolerance.

Doklady Biological Sciences. 2018;478(1):33-36
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Functional Orientation of Biochemical Processes in Female Beluga × Sterlet (Acipenser ruthenus Linnaeus, 1758 × Huso huso Linnaeus, 1758) Hybrids in the Reproductive Cycle

Metallov G., Ponomareva E., Sorokina M., Grigoryev V., Korchunov A.

Аннотация

The article reports data on the dynamics of blood parameters and parameters of protein, fat, and water–salt metabolism in female starlet × beluga hybrids kept under artificial conditions in the period of reproductive cycle. Gonad maturation in female hybrids in the artificial environment causes clear changes in the biochemistry of blood and of urine.

Doklady Biological Sciences. 2018;478(1):37-39
pages 37-39 views