Genetic dissection of haploid male fertility in maize (Zea mays L.)

Haploid genome doubling is a key limiting step of haploid breeding in maize. Spontaneous restoration of haploid male fertility (HMF) provides a more promising method than the artificial doubling process. To reveal the genetic basis of HMF, haploids were obtained from the offspring of 285 F2:3 families, derived from the cross Zheng58 × K22. The F2:3 families were used as the female donor and Yu high inducer No. 1 (YHI‐1) as the male inducer line. The rates of HMF from each family line were evaluated at two field sites over two planting seasons. HMF displayed incomplete dominance. Transgressive segregation of haploids from F2:3 families was observed relative to haploids derived from the two parents of the mapping population. A total of nine quantitative trait loci (QTL) were detected, which were distributed on chromosomes 1, 3, 4, 7 and 8. Three major QTL, qHMF3b, qHMF7a and qHMF7b were detected in both locations, respectively. These QTL could be useful to predict the ability of spontaneous haploid genome doubling, and to accelerate the haploid breeding process by introgression or aggregation of those QTL

A diallel analysis of a maize donor population response to In vivo maternal haploid induction II: haploid male fertility

Doubled haploid (DH) lines are used in maize breeding to accelerate the breeding cycle and create homogenous inbred lines in as little as two seasons. These pure inbred lines allow breeders to quickly evaluate new cross combinations. There are two important steps in creating DH lines: 1) generation and selection of haploid progeny, and 2) genome doubling to create fertile, diploid inbreds. Colchicine is widely used to artificially double genomes in haploid plants, which is hazardous, expensive, and time consuming. In this study, three public inbred lines A427, A637, and NK778 were found to have substantial haploid male fertility (HMF). A six-parent full diallel between these three HMF lines and three non-HMF lines was created and HMF was scored. Diallel analysis revealed significant GCA estimates of up to 17% for HMF, as well as significant SCA effects of up to 25%. No significant reciprocal effects were found. HMF is promising to be incorporated into elite maize breeding programs to potentially overcome the need of using colchicine treatments for genome doubling. Colchicine aided doubling success rates varying from almost zero to 30%. HMF has an advantage over artificial genome doubling both in terms of increased success rates and decreased costs for DH line production

Бремя новой коронавирусной инфекции в детском многопрофильном стационаре Санкт-Петербурга 2020–2021 гг.

Objective: To describe the burden of COVID-19 in a children’s multidisciplinary hospital for two years of the pandemic, taking into account of age, severity of the disease, the spectrum of underlying conditions and the intensive care need.Methods: An assessment of 6048 cases of COVID-19 in patients under 18 years of age hospitalized from March 26, 2020 to December 31, 2021 was carried out. The diagnosis was confirmed by PCR on an outpatient basis or after hospitalization with the help of diagnostic kits registered in the Russian Federation. The features of the work of a children’s multidisciplinary hospital in new conditions, the dynamics of hospitalization, age characteristics and new coronavirus (CV) infection severity in the pandemic development process are presented. The analysis of the underlying condition’s structure depending on the severity of the disease, as well as the need and volume of therapy in the intensive care unit. The frequency and main characteristics of children’s multisystem inflammatory syndrome (MIS-C) in hospital conditions, long-term PCR positivity and its effect on the duration of inpatient treatment of children have been established.Results: The spread of SARS-COV-2 in St. Petersburg required a radical change in the work of the children’s multidisciplinary hospital. During the two years of the pandemic, four waves of hospitalization of children with new CV were revealed, differing in duration, intensity, and frequency of lung damage, but having no significant differences in the proportion of severe forms of the disease (1.7-2.8% of cases). Intensive therapy was required in 3.6% of cases, of which only 1/3 was due to the severe course of COVID-19 with a lung lesion volume of up to 100%. In 1/3 of cases, patients had risks of developing severe forms and in 1/3 – other pathology. Severe course of new CV was significantly more often accompanied by the need for respiratory support, anticoagulants and anti-inflammatory therapy. Contributing factors of severe forms and unfavorable outcomes were: pathology of the central nervous system, genetic diseases and malformations, obesity, as well as chronic bronchopulmonary pathology. Mortality in the hospital was recorded only among children with severe underlying conditions (0.1% of cases). D-MVS was registered significantly more often in boys (7 out of every 10 patients), accounting for 1.2% of cases of hospitalization of children with new CV over the entire period. Convalescent PCR-positivity in the outcome of COVID-19 was detected in 1/3 of children, significantly more often during the autumnwinter waves of the pandemic and among patients of high school age.Conclusion: New CV is gradually strengthening its position in the structure of acute respiratory pathology in children. Some of SARS-COV-2 infection cases is accompanied by extensive lung damage, as well as severe systemic inflammation independently or in the other infectious diseases structure, induction of the debut of various somatic pathology is not excluded. The presented data confirm the need for increased attention at high risk of adverse respiratory diseases outcomes children. All severe cases of COVID-19 in children require a personalized approach, taking into account the existing background diseases and possible options for the progression of the process. MIS-C should be considered as a systemic inflammatory response syndrome within the framework of an infectious disease of various etiologies, differentiated with Kawasaki disease and the debut of systemic diseases. The long-term PCR-positivity in the outcome of COVID-19 requires further study to address the need and nature of therapy in order to prevent further spread of infection in the population.Цель: описать бремя COVID-19 в детском многопрофильном стационаре за два года пандемии с учетом возраста, тяжести заболевания, спектра сопутствующей патологии и потребности в интенсивной терапии.Материалы и методы: проведена оценка 6048 случаев COVID-19 у пациентов до 18 лет, госпитализированных с 26 марта 2020 г. по 31 декабря 2021 г. Диагноз подтверждался методом полимеразной цепной реакции амбулаторно или после госпитализации с помощью зарегистрированных в РФ диагностических наборов. Представлены особенности работы детского многопрофильного стационара в новых условиях, динамика госпитализации, возрастная характеристика и тяжесть новой коронавирусной инфекции в процессе развития пандемии. Проведен анализ структуры сопутствующей патологии в зависимости от тяжести течения заболевания, а также потребности и объема терапии в отделении реанимации. Установлены частота и основные характеристики детского мультисистемного воспалительного синдрома в условиях стационара, длительной ПЦР-позитивности и ее влияния на продолжительность стационарного лечения детей.Результаты: распространение SARS-COV-2 в Санкт-Петербурге потребовало кардинального изменения работы детского многопрофильного стационара. За 2 года пандемии выявлено 4 волны госпитализации детей с новой коронавирусной инфекцией, отличавшиеся продолжительностью, интенсивностью, частотой поражения легких, но не имевшие значимых различий по доле тяжелых форм заболевания (1,7–2,8% случаев). Интенсивная терапия потребовалась в 3,6% случаев, из них лишь в 1/3 – по причине тяжелого течения COVID-19 с объемом поражения легких до 100%. В 1/3 случаев у пациентов имелись риски развития тяжелых форм и в 1/ – другая патология. Тяжелое течение новой коронавирусной инфекции значимо чаще сопровождалось потребностью в аппаратной респираторной поддержке, антикоагулянтах и противовоспалительной терапии. Предрасполагающими факторами тяжелых форм и неблагоприятных исходов явились: патология центральной нервной системы, генетические заболевания и пороки развития, ожирение, а также хроническая бронхолегочная патология. Летальность в стационаре была зафиксирована только среди детей с тяжелой сопутствующей патологией (0,1% случаев). Детский мультисистемный воспалительный синдром регистрировался значимо чаще у мальчиков (7 из каждых 10 пациентов), составив 1,2% случаев госпитализации детей с новой коронавирусной инфекцией за весь период. Реконвалесцентная ПЦР-позитивность в исходе COVID-19 выявлена у 1/3 детей, значимо чаще во время осеннезимних волн пандемии и среди пациентов старшего школьного возраста.Заключение: НКВИ постепенно укрепляет свои позиции в структуре острой респираторной патологии у детей. В ряде случаев инфицирование SARS-COV-2 сопровождается обширным поражением легких, а также тяжелым системным воспалением самостоятельно или в структуре других инфекционных заболеваний, не исключена индукция дебюта различной соматической патологии. Представленные данные подтверждают необходимость повышенного внимания к детям групп риска неблагоприятных исходов респираторных заболеваний. Все тяжелые случаи COVID-19 у детей требуют персонализированного подхода с учетом имеющихся фоновых заболеваний и возможных вариантов прогрессирования процесса. Детский мультисистемный воспалительный синдром следует рассматривать как синдром системного воспалительного ответа в рамках инфекционного заболевания различной этиологии, дифференцировать с болезнью Кавасаки и дебютом системных заболеваний. Длительная ПЦР-позитивность в исходе COVID-19 требует дальнейшего изучения для решения вопроса о необходимости и характере терапии с целью предотвращения распространения инфекции в популяции

Beryllium Layer Response to ITER-Like ELM Plasma Pulses in QSPA-Be

Material migration in ITER is expected to move beryllium (Be) eroded from the first wall primarily to the tungsten (W) divertor region and to magnetically shadowed areas of the wall itself. This paper is concerned with experimental study of Be layer response to ELM-like plasma pulses using the new QSPA-Be plasma gun (SRC RF TRINITI). The Be layers (1 → 50 µm thick) are deposited on special castellated Be and W targets supplied by the ITER Organization using the Thermionic Vacuum Arc technique. Transient deuterium plasma pulses with duration ∼0.5 ms were selected to provide absorbed energy densities on the plasma stream axis for a 30° target inclination of 0.2 and 0.5 MJm−2, the first well below and the second near the Be melting point. This latter value is close to the prescribed maximum energy density for controlled ELMs on ITER. At 0.2 MJm−2 on W, all Be layer thicknesses tested retain their integrity up to the maximum pulse number, except at local defects (flakes, holes and cracks) and on tile edges. At 0.5 MJm−2 on W, Be layer melting and melt layer agglomeration are the main damage processes, they happen immediately in the first plasma impact. Melt layer movement was observed only near plasma facing edges. No significant melt splashing is observed in spite of high plasma pressure (higher than expected in ITER). Be layer of 10 µm thick on Be target has higher resistance to plasma irradiation than 1 and 55 µm, and retain their integrity up to the maximum pulse number at 0.2 MJm−2. For 1 µm and 55 µm thick on Be target significant Be layer losses were observed at 0.2 MJm−2