The highly divergent Jekyll genes, required for sexual reproduction, are lineage specific for the related grass tribes Triticeae and Bromeae

Phylogenetically related groups of species contain lineage-specific genes that exhibit no sequence similarity to any genes outside the lineage. We describe here that the Jekyll gene, required for sexual reproduction, exists in two much diverged allelic variants, Jek1 and Jek3. Despite low similarity, the Jek1 and Jek3 proteins share identical signal peptides, conserved cysteine positions and direct repeats. The Jek1/Jek3 sequences are located at the same chromosomal locus and inherited in a monogenic Mendelian fashion. Jek3 has a similar expression as Jek1 and complements the Jek1 function in Jek1-deficient plants. Jek1 and Jek3 allelic variants were almost equally distributed in a collection of 485 wild and domesticated barley accessions. All domesticated barleys harboring the Jek1 allele belong to single haplotype J1-H1 indicating a genetic bottleneck during domestication. Domesticated barleys harboring the Jek3 allele consisted of three haplotypes. Jekyll-like sequences were found only in species of the closely related tribes Bromeae and Triticeae but not in other Poaceae. Non-invasive magnetic resonance imaging revealed intrinsic grain structure in Triticeae and Bromeae, associated with the Jekyll function. The emergence of Jekyll suggests its role in the separation of the Bromeae and Triticeae lineages within the Poaceae and identifies the Jekyll genes as lineage-specific

Issues of self-education in the continuous professional development of dentists of Ukraine in the conditions of the Covid-19 pandemic

Background: The rapid development of the dental industry and the daily practice of dentists necessitate constant learning because replenishing the stock of acquired knowledge and skills is the basis for the formation of a highly qualified specialist. Self-directed learning, especially reading and purposeful work with medical literature, constantly contribute to the development of thinking, which should correspond to the modern level of science in medical professionals in the context of the Covid-19 pandemic. The aim of the study was to monitor and analyze ways to obtain new scientific and practical knowledge by dentists to improve their dental practice. Materials and methods: The study involved 4.026 dentists who filled out for dentists online. Results: To improve daily dental practice, dentists additionally use information that is provided in lectures at scientific and practical events (80.19%) and Internet resources (71.48%). For dentists, the most convenient way to read scientific and practical articles was through the electronic version on the websites of the journals (62.20%). Informing doctors with articles with well-illustrated clinical cases (72.66%) and lectures along with practical materials (64.75%) are of the greatest interest to the vast majority of dentists. Conclusion: According to the analytical results, it is shown that the main ways of obtaining scientific and practical information for dentists in the process of self-directed learning is the active involvement of the materials gained on the lectures, scientific and practical events, from Internet resources, from scientific and methodological literature, from scientific articles of domestic and foreign English-language professional journals

Development of maternal seed tissue in barley is mediated by regulated cell expansion and cell disintegration and coordinated with endosperm growth

After fertilization, filial grain organs are surrounded by the maternal nucellus embedded within the integuments and pericarp. Rapid early endosperm growth must be coordinated with maternal tissue development. Parameters of maternal tissue growth and development were analysed during early endosperm formation. In the pericarp, cell proliferation is accomplished around the time of fertilization, followed by cell elongation predominantly in longitudinal directions. The rapid cell expansion coincides with endosperm cellularization. Distribution of TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling)-positive nuclei reveals distinct patterns starting in the nucellus at anthesis and followed later by the inner cell rows of the pericarp, then spreading to the whole pericarp. The pattern suggests timely and spatially regulated programmed cell death (PCD) processes in maternal seed tissues. When the endosperm is coenocytic, PCD events are only observed within the nucellus. Thereby, remobilization of nucellar storage compounds by PCD could nourish the early developing endosperm when functional interconnections are absent between maternal and filial seed organs. Specific proteases promote PCD events. Characterization of the barley vacuolar processing enzyme (VPE) gene family identified seven gene members specifically expressed in the developing grain. HvVPE2a (known as nucellain) together with closely similar HvVPE2b and HvVPE2d might be involved in nucellar PCD. HvVPE4 is strongly cell specific for pericarp parenchyma. Correlative evidence suggests that HvVPE4 plays a role in PCD events in the pericarp. Possible functions of PCD in the maternal tissues imply a potential nutritive role or the relief of a physical restraint for endosperm growth. PCD could also activate post-phloem transport functions

SWEET11b transports both sugar and cytokinin in developing barley grains

Even though Sugars Will Eventually be Exported Transporters (SWEETs) have been found in every sequenced plant genome, a comprehensive understanding of their functionality is lacking. In this study, we focused on the SWEET family of barley (Hordeum vulgare). A radiotracer assay revealed that expressing HvSWEET11b in African clawed frog (Xenopus laevis) oocytes facilitated the bidirectional transfer of not only just sucrose and glucose, but also cytokinin. Barley plants harboring a loss-of-function mutation of HvSWEET11b could not set viable grains, while the distribution of sucrose and cytokinin was altered in developing grains of plants in which the gene was knocked down. Sucrose allocation within transgenic grains was disrupted, which is consistent with the changes to the cytokinin gradient across grains, as visualized by magnetic resonance imaging and Fourier transform infrared spectroscopy microimaging. Decreasing HvSWEET11b expression in developing grains reduced overall grain size, sink strength, the number of endopolyploid endosperm cells, and the contents of starch and protein. The control exerted by HvSWEET11b over sugars and cytokinins likely predetermines their synergy, resulting in adjustments to the grain's biochemistry and transcriptome

A chromosome conformation capture ordered sequence of the barley genome

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Дослідження ефективності конструкцій фільтрувальних коробок

Background. Filtering respirators are widely used in various industries to protect workers from dust, so studies aimed at improving ergonomic parameters of personal respiratory protection are relevant.Objective. The aim of the paper is the filter box design influence on respirator breathing resistance.Methods. The distribution of the air flow rate and the pressure drop across the filter was determined in accordance with the requirements of the DSTU EN 143: 2002. To do this, in the back wall of the filter box housing 5 mm holes were drilled, in which every 10 mm a Pitot tube was installed, connected to an electronic manometer Testo 512.Results. It is established that the designs of filter boxes affect the pressure drop of the respirator, due to the failure to use a significant surface of the filters (the formation of dead zones in which air does not move) what affects the efficiency of their performance.Conclusions. The designs of filter boxes for modern respirators require appropriate modification to reduce the resistance to breathing, to increase the duration of protection and dust load, due to uniform flow around the filter surface by air flow throughout the area.Проблематика. Фильтровальные респираторы широко применяются в различных отраслях производства для защиты работников от пыли, поэтому исследования, направленные на улучшение эргономических параметров средств индивидуальной защиты органов дыхания, актуальны.Цель исследований. Исследование влияния конструкции фильтровальной коробки на сопротивление дыханию респиратора.Методика реализации. Распределение скорости воздушного потока и перепада давления на фильтре определяли в соответствии с требованиями ДСТУ EN 143: 2002. Для этого в задней стенке корпуса фильтровальной коробки просверлили отверстия размером5 мм, в которые через каждые10 мм устанавливалась трубка Пито, подключенная к электронному манометру Testo 512.Результаты исследований. Установлено, что существующие конструкции фильтровальных коробок влияют на перепад давления респиратора из-за неиспользования значительной поверхности фильтров (образование мертвых зон, в которых воздух не движется), что сказывается на эффективности их работы.Выводы. Конструкции фильтровальных коробок к современным респираторам требуют соответствующей доработки с целью уменьшения сопротивления дыханию, увеличения срока защитного действия и пылеемкости за счет равномерного обтекания поверхности фильтра воздушным потоком по всей площади.Проблематика. Фільтрувальні респіратори широко застосовуються в різних галузях виробництва для захисту працівників від пилу, тому дослідження, спрямовані на покращення ергономічних параметрів засобів індивідуального захисту органів дихання, є актуальними.Мета досліджень. Дослідження впливу конструкції фільтрувальної коробки на опір диханню респіратора.Методика реалізації. Розподіл швидкості повітряного потоку і перепаду тиску на фільтрі визначали відповідно до вимог ДСТУ EN 143:2002. Для цього в задній стінці корпуса фільтрувальної коробки просвердлили отвори розміром 5 мм, у які через кожні 10 мм встановлювалась трубка Піто, під’єднана до електронного манометра Testo 512.Результати досліджень. Встановлено, що існуючі конструкції фільтрувальних коробок впливають на перепад тиску респіратора через невикористання значної поверхні фільтрів (утворення мертвих зон, у яких повітря не рухається), що позначається на ефективності їх роботи.Висновки. Конструкції фільтрувальних коробок до сучасних респіраторів потребують відповідного доопрацювання з метою зменшення опору диханню, збільшення строку захисної дії та пиломісткості за рахунок рівномірного обтікання поверхні фільтра повітряним потоком за всією площею

Jekyll Encodes a Novel Protein Involved in the Sexual Reproduction of Barley

Cereal seed development depends on the intimate interaction of filial and maternal tissues, ensuring nourishment of the new generation. The gene jekyll, which was identified in barley (Hordeum vulgare), is preferentially expressed in the nurse tissues. JEKYLL shares partial similarity with the scorpion Cn4 toxin and is toxic when ectopically expressed in Escherichia coli and tobacco (Nicotiana tabacum). In barley, jekyll is upregulated in cells destined for autolysis. The gene generates a gradient of expression in the nucellar projection, which mediates the maternal–filial interaction during seed filling. Downregulation of jekyll by the RNA interference technique in barley decelerates autolysis and cell differentiation within the nurse tissues. Flower development and seed filling are thereby extended, and the nucellar projection no longer functions as the main transport route for assimilates. A slowing down in the proliferation of endosperm nuclei and a severely impaired ability to accumulate starch in the endosperm leads to the formation of irregular and small-sized seeds at maturity. Overall, JEKYLL plays a decisive role in the differentiation of the nucellar projection and drives the programmed cell death necessary for its proper function. We further suggest that cell autolysis during the differentiation of the nucellar projection allows the optimal provision of basic nutrients for biosynthesis in endosperm and embryo

Caspase-Like Activities Accompany Programmed Cell Death Events in Developing Barley Grains

<div><p>Programmed cell death is essential part of development and cell homeostasis of any multicellular organism. We have analyzed programmed cell death in developing barley caryopsis at histological, biochemical and molecular level. Caspase-1, -3, -4, -6 and -8-like activities increased with aging of pericarp coinciding with abundance of TUNEL positive nuclei and expression of <i>HvVPE4</i> and <i>HvPhS2</i> genes in the tissue. TUNEL-positive nuclei were also detected in nucellus and nucellar projection as well as in embryo surrounding region during early caryopsis development. Quantitative RT-PCR analysis of micro-dissected grain tissues revealed the expression of <i>HvVPE2a</i>, <i>HvVPE2b</i>, <i>HvVPE2d</i>, <i>HvPhS2</i> and <i>HvPhS3</i> genes exclusively in the nucellus/nucellar projection. The first increase in cascade of caspase-1, -3, -4, -6 and -8-like activities in the endosperm fraction may be related to programmed cell death in the nucellus and nucellar projection. The second increase of all above caspase-like activities including of caspase-9-like was detected in the maturating endosperm and coincided with expression of <i>HvVPE1</i> and <i>HvPhS1</i> genes as well as with degeneration of nuclei in starchy endosperm and transfer cells. The distribution of the TUNEL-positive nuclei, tissues-specific expression of genes encoding proteases with potential caspase activities and cascades of caspase-like activities suggest that each seed tissue follows individual pattern of development and disintegration, which however harmonizes with growth of the other tissues in order to achieve proper caryopsis development.</p></div