Mutual maintenance of di- and triploid Pelophylax esculentus hybrids in R-E systems: results fro

Background: Interspecies animal hybrids can employ clonal or hemiclonal reproduction modes where one or all parental genomes are transmitted to the progeny without recombination. Nevertheless, some interspecies hybrids retain strong connection with the parental species needed for successful reproduction. Appearance of polyploid hybrid animals may play an important role in the substitution of parental species and in the speciation process. Results: To establish the mechanisms that enable parental species, diploid and polyploid hybrids coexist we have performed artificial crossing experiments of water frogs of Pelophylax esculentus complex. We identified tadpole karyotypes and oocyte genome composition in all females involved in the crossings. The majority of diploid and triploid hybrid frogs produced oocytes with 13 bivalents leading to haploid gametes with the same genome as parental species hybrids usually coexist with. After fertilization of such gametes only diploid animals appeared. Oocytes with 26 bivalents produced by some diploid hybrid frogs lead to diploid gametes, which give rise to triploid hybrids after fertilization. In gonads of all diploid and triploid hybrid tadpoles we found DAPI-positive micronuclei (nucleus-like bodies) involved in selective genome elimination. Hybrid male and female individuals produced tadpoles with variable karyotype and ploidy even in one crossing owing to gametes with various genome composition. Conclusions: We propose a model of diploid and triploid hybrid frog reproduction in R-E population systems. Triploid Pelophylax esculentus hybrids can transmit genome of parental species they coexist with by producing haploid gametes with the same genome composition. Triploid hybrids cannot produce triploid individuals after crossings with each other and depend on diploid hybrid females producing diploid eggs. In contrast to other population systems, the majority of diploid and triploid hybrid females unexpectedly produced gametes with the same genome as parental species hybrids coexist with

Expression profiles of long and short RNA s in the cytoplasm and nuclei of growing chicken (Gallus gallus domesticus) oocytes

Maternal RNAs accumulated during oocyte maturation are required not only for zygote formation but also for supporting the first embryonic cell divisions until embryo genome activation. Essential stages of transcriptome analysis include adaptation of RNA extraction procedures and characterization of the RNA expression profile. Ovaries of domestic birds represent an adequate model for exploration of RNA accumulation during oogenesis. In the present study, we optimized methods of RNA extraction from chicken (Gallus gallus domesticus) oocyte cytoplasm and nucleoplasm and characterized changes in profiles of long and short RNAs during oocyte growth. Cytoplasmic RNA fractions contained 28S and 18S ribosomal RNAs (rRNAs), small RNAs, and long RNAs heterogeneous in size. The profiles of total RNA from growing oocyte nuclei were dominated by low molecular weight RNAs corresponding in size to transport RNAs, small nuclear RNAs, and short regulatory RNAs. Importantly, oocyte nuclei from chicken egglaying females demonstrated trace amounts or absence of 28S and 18S rRNA, which was due to inactivation of the only nucleolar organizer. Three groups of short RNAs differing in size (from 20 to 40 nucleotides) were recognized in chicken oocytes. They might correspond to short regulatory RNA classes. Furthermore, we demonstrated that short RNAs were accumulated in the cytoplasm during oocyte growth. We suggest that short RNAs accumulated in avian oocyte cytoplasm are involved in the regulation of genome functions at early embryogenesis stages

Ultra-broadband Noise-Insulating Periodic Structures Made of Coupled Helmholtz Resonators

Acoustic metamaterials and phononic crystals represent a promising platform for the development of noise-insulating systems characterized by a low weight and small thickness. Nevertheless, the operational spectral range of these structures is usually quite narrow, limiting their application as substitutions of conventional noise-insulating systems. In this work, the problem is tackled by demonstration of several ways for the improvement of noise-insulating properties of the periodic structures based on coupled Helmholtz resonators. It is shown that tuning of local coupling between the resonators leads to the formation of ultra-broad stop-bands in the transmission spectra. This property is linked to band structures of the equivalent infinitely periodic systems and is discussed in terms of band-gap engineering. The local coupling strength is varied via several means, including introduction of the so-called chirped structures and lossy resonators with porous inserts. The stop-band engineering procedure is supported by genetic algorithm optimization and the numerical calculations are verified by experimental measurements

Localization of xeroderma pigmentosum group A protein and replication protein A on damaged DNA in nucleotide excision repair

The interaction of xeroderma pigmentosum group A protein (XPA) and replication protein A (RPA) with damaged DNA in nucleotide excision repair (NER) was studied using model dsDNA and bubble-DNA structure with 5-{3-[6-(carboxyamido-fluoresceinyl)amidocapromoyl]allyl}-dUMP lesions in one strand and containing photoreactive 5-iodo-dUMP residues in defined positions. Interactions of XPA and RPA with damaged and undamaged DNA strands were investigated by DNA–protein photocrosslinking and gel shift analysis. XPA showed two maximums of crosslinking intensities located on the 5′-side from a lesion. RPA mainly localized on undamaged strand of damaged DNA duplex and damaged bubble-DNA structure. These results presented for the first time the direct evidence for the localization of XPA in the 5′-side of the lesion and suggested the key role of XPA orientation in conjunction with RPA binding to undamaged strand for the positioning of the NER preincision complex. The findings supported the mechanism of loading of the heterodimer consisting of excision repair cross-complementing group 1 and xeroderma pigmentosum group F proteins by XPA on the 5′-side from the lesion before damaged strand incision. Importantly, the proper orientation of XPA and RPA in the stage of preincision was achieved in the absence of TFIIH and XPG

Commercial chicken breeds exhibit highly divergent patterns of linkage disequilibrium

The analysis of linkage disequilibrium (LD) underpins the development of effective genotyping technologies, trait mapping and understanding of biological mechanisms such as those driving recombination and the impact of selection. We apply the Malécot-Morton model of LD to create additive LD maps that describe the high-resolution LD landscape of commercial chickens. We investigated LD in chickens (Gallus gallus) at the highest resolution to date for broiler, white egg and brown egg layer commercial lines. There is minimal concordance between breeds of fine-scale LD patterns (correlation coefficient <0.21), and even between discrete broiler lines. Regions of LD breakdown, which may align with recombination hot spots, are enriched near CpG islands and transcription start sites (P<2.2 × 10?16), consistent with recent evidence described in finches, but concordance in hot spot locations between commercial breeds is only marginally greater than random. As in other birds, functional elements in the chicken genome are associated with recombination but, unlike evidence from other bird species, the LD landscape is not stable in the populations studied. The development of optimal genotyping panels for genome-led selection programmes will depend on careful analysis of the LD structure of each line of interest. Further study is required to fully elucidate the mechanisms underlying highly divergent LD patterns found in commercial chickens

ВЫЯВЛЕНИЕ И ДИСПАНСЕРНОЕ НАБЛЮДЕНИЕ ДЕТЕЙ С СИНДРОМОМ УДЛИНЕННОГО ИНТЕРВАЛА QT

Aim To assess the diagnostic accuracy of long QT syndrome in children and to estimate the results of the follow-up.Methods High-risk groups of children with bradycardia less than the second percentile and/or a family history of sudden death syndrome, and children with syncope diagnosed with the ECG testing were included in the study. All patients underwent routine medical examination, molecular genetic testing and were followed-up for 3,5–10 years.Results The majority of children haves transient corrected QT prolongation secondary to therapy, requiring ECG monitoring. High-risk group screening reports higher rates of idiopathic LQTS. ECG testing shows its efficiency among asymptomatic children with a normal heart rate. Patients present with syncope at the outpatient settings require the exclusion of a wide range of diseases, both congenital and acquired heart disease. The clinical status of the examined patients does not always correspond to the known LQTS variants. Molecular genetic analysis provides relevant information on the genetic heterogeneity of the disease, including new mutations, both pathological and beneficial ones.Conclusion Regardless of the presence or absence of molecular genetic confirmation of LQTS, beta blocker therapy in some cases combined with implanted cardioverterdefibrillator prevents the development of the adverse events in the long-term period and ensures normal emotional, intellectual and physical development.Цель Изучить эффективность диагностики синдрома удлиненного интервала QT (СУИQT) у детей и результаты наблюдения детей по данным катамнеза.Материалы и методы Проведено обследование детей двух групп риска – новорожденных с брадикардией менее 2 перцентиля и семейным анамнезом внезапной смерти, и детей с синкопе с помощью ЭКГ-скрининга, комплексного обследования выделенных групп, и наблюдение детей в течение 3,5–10 лет .Результаты Установлено, что в периоде новорожденности значительная часть детей имеет преходящее вторичное удлинение корригированного QT, что требует ЭКГ-контроля после лечения. Обследование детей из групп риска имеет большую вероятность выявления пациентов с идиопатическим СУИQT, тогда как у бессимптомных детей с нормальной частотой сердечного ритма выявление больных возможно только при проведении ЭКГ-скрининга. У пациентов с синкопе на амбулаторном этапе обследования необходимо исключение широкого спектра заболеваний, включая врожденные и приобретенные болезни сердца. Клинический статус наблюдаемых больных не всегда соответствует известным вариантам СУИQT.Заключение Независимо от наличия или отсутствия молекулярно-генетического подтверждения диагноза терапия бета-адреноблокаторами, и в ряде случаев ее сочетание в комбинации с имплантированным кардиовертером-дефибриллятором обеспечивает в течение длительного времени клиническую стабильность пациентов, удовлетворительные темпы эмоционального, интеллектуального и физического развития, предотвращает развитие сердечных событий с неблагоприятным исходом