bluuebunny/crossref_metadata_2025 huggingface dataset:
Whole-genome characterisation of multidrug resistant monophasic variants ofSalmonellaTyphimurium from pig production in Thailand
Authors: Patchanee Prapas , Tanamai Prawitchaya , Tadee Phacharaporn , Hitchings Matthew D. , Calland Jessica K. , Sheppard Samuel K. , Meunsene Dethaloun , Pascoe Ben , Tadee Pakpoom
Published: August 2020

Background

MonophasicSalmonellaTyphimurium orS. enterica1,4,[5],12:i:- is among the top five serotypes reported in Thailand. In this study, nineteen monophasicS. Typhimurium from the pig production chain in Chiang Mai and Lamphun provinces during 2011–2014 were sequenced and compared to a globally disseminated clone. Isolates were probed in silico for the presence of antimicrobial resistance genes andSalmonellavirulence factors, including Pathogenicity Islands.

Results

All isolates were from sequence type 34 (ST-34) and clustered similarly in core and pangenome genealogies. The two closest related isolates showed differences in only eighteen loci from whole-genome multilocus sequence typing analysis. All 19 isolates carried aminoglycoside and beta-lactam class resistance genes and genes for five or more different antibiotic classes. Seven out of 14 known SPIs were detected, including SPI-5, SPI-13 and SPI-14, which were detected in all isolates.

Conclusions

The multi-drug resistant clone, ST-34 was sampled at all stages of pork production. This clone has infiltrated global agricultural processes and poses a significant public health risk. Differences in the core and accessory genomes of the isolates we collected suggest that strains persist though the pork production process, with evidence of mutation within the core-genome and horizontal acquisition of genes, potentially via sharing of pathogenicity islands and plasmids. This highlights the importance of surveillance and targeted intervention measures to successfully controlSalmonellacontamination.
Larval longevity and competency patterns of Caribbean reef-building corals
Authors: Miller Margaret W. , Bright Allan J. , Pausch Rachel E. , Williams Dana E.
Published: August 2020

The potential for long-distance larval dispersal depends on the longevity of planktonic, free-swimming larvae and their capacity to successfully recruit to reef habitat. We present multi-year laboratory observations of the persistence of planular larvae and settlement competency over time for cohorts derived from the same parental populations of the most important Caribbean reef building coral species, Orbicella faveolata and Acropora spp. Despite variability among years/cohorts, larvae of both species display capacity for extended longevity (up to 83 d) and competency (demonstrated at up to 48 d). Both species also displayed significantly reduced survivorship and lower realized settlement under elevated temperatures. Although the observed levels of settlement in 24 h competency assays was extremely variable, the timing of onset of competence were highly consistent among years/cohorts but distinct between species. Orbicella faveolata displayed onset of competence during day 3–5 or 4–7 (with or without exposure to positive settlement cue) after spawning; whereas, onset for Acropora spp. was day 7–8 or day 10–11 (with or without cue, respectively). This longer pre-competency period for Acropora spp. nonetheless corresponded to a greater persistence of A. palmata larvae to this age of competence (71–83% of initial cohort compared to 54–55% for O. faveolata). Such life history variation implies meaningful differences in likely dispersal potential between these imperiled reef-building species.
Молекулярные методы для контроля пандемии COVID-19, "Природа"
Authors: Бевова Марианна Руслановна , Мошковский Сергей Александрович , Нетёсов Сергей Викторович , Аульченко Юрий Сергеевич
Published: August 2020

«Пневмония неизвестной этиологии», которая впервые была выявлена в конце декабря прошлого года в китайской провинции Хубэй и, как вскоре выяснилось, была вызвана вирусом SARS-CoV-2, к концу апреля уже поразила миллионы людей во всем мире. Пандемия COVID-19 - серьезный вызов не только системе здравоохранения, но и ученым всех стран. В перспективе нескольких лет можно надеяться на разработку вакцин и эффективного лечения COVID-19. А пока основным инструментом контроля пандемии скорее всего останется проведение карантинных мероприятий разной степени жесткости. Для достижения баланса между скоростью распространения вируса в популяции и негативным экономическим эффектом карантина чрезвычайно важную роль будет играть лабораторная диагностика. Каковы особенности распространения COVID-19 Какие методы диагностики уже существуют и какие появятся в ближайшем будущем А кроме того, почему одни люди переносят инфекцию легко, а других она убивает
Зоя Петровна Тиховская: женская судьба и наука в эпоху перемен, "Природа"
Authors: Степаньян О.В.
Published: August 2020

История гидробиологических и альгологинеских исследований на Русском Севере насчитывает более 150 лет. Наиболее значимые научные открытия были сделаны выдающимися учеными-женщинами - Е.С.Зиновой, А.Д.Зиновой, Е.Ф.Гурьяновой. В одном ряду с ними стоит З.П.Тиховская (1889-1976), первый альголог Мурманской биологической станции, созданной в 1937 г. в пос.Дальние Зеленцы Мурманской обл. Жизнь Зои Петровны была нелегкой. Но она сумела выполнить огромный объем эколого-физиологических исследований на различных ботанических объектах. Особое место в ее научной работе занимали водоросли Баренцева моря. Она изучала механизмы их адаптации к действию полярного дня и ночи, изменениям температуры воды, исследовала распределение промысловых запасов и видового состава макроводорослей Восточного Мурмана. Полученные ею результаты актуальны и в настоящее время. Вместе с тем роль Зои Петровны в истории и научной жизни Севастопольской и Мурманской биологических станций остается недостаточно освещенной.
Не «просто грипп», или особенности иммунного ответа при COVID-19, "Природа"
Authors: Кондратова Мария Сергеевна
Published: August 2020

Еще недавно проблемы регуляции иммунитета при вирусных инфекциях интересовали лишь специалистов (инфекционистов, иммунологов и т.д.). Однако из-за внезапной вспышки пандемии COVID-19 эти вопросы оказались в центре всеобщего внимания. В обзоре рассмотрен общий порядок развития иммунного ответа при вирусных инфекциях, который изучен уже довольно хорошо, а также проанализированы основные его отклонения при COVID-19, исследованные к настоящему времени. В нем именно заключаются различия в иммунном ответе при новой коронавирусной инфекции и «обычных» ОРВИ, с которыми наш организм сталкивается каждый год Как эти отклонения сказываются на тяжести болезни у людей, которые заразились SARS-CoV-2
КОНЦЕНТРАЦИЯ НАПРЯЖЕНИЙ В ПОЛИМЕРНЫХ ФРИКЦИОННЫХ КОМПОЗИТАХ С ХАОТИЧЕСКИ ОРИЕНТИРОВАННЫМИ СТЕКЛЯННЫМИ ВОЛОКНАМИ И ДИСПЕРСНЫМИ ДОБАВКАМИ КАУЧУКА, ГЛИНОЗЕМА, ГРАФИТА И БАРИТА, "Наука Юга России"
Authors: Колесников В.И. , Бардушкин В.В. , Лавров И.В. , Сычев А.П. , Сычев А.А. , Яковлев В.Б.
Published: August 2020

В работе решается задача построения модели прогнозирования значений локальных упругих характеристик полимерных фрикционных композитов, определяемых оператором концентрации напряжений (тензором четвертого ранга). Указанный тензор связывает значения локальных (внутренних) напряжений в каждом элементе неоднородности композита со значениями средних (внешних) напряжений в материале. Построенная модель опирается на обобщенное сингулярное приближение теории случайных полей, используемое при решении стохастического дифференциального уравнения равновесия упругой среды. С помощью указанного приближения возможен анализ изменения значений компонент оператора концентрации напряжений в зависимости от состава, структуры и объемного содержания наполнителей композита. Объектом моделирования в работе являются полимерные фрикционные композиты на эпоксифенольной основе, армированные хаотически ориентированными в пространстве материала короткими волокнами бесщелочного стекла и дисперсными добавками каучука, глинозема, графита и барита. Проведены численные модельные расчеты значений компонент оператора концентрации напряжений, опирающиеся на разработанную модель и учитывающие изменения объемных содержаний наполнителей неоднородных материалов. Для компонент 1111 и 1212 рассматриваемого тензора, наиболее полно характеризующих перераспределение напряжений между элементами неоднородности композита при приложении к нему сжимающих и сдвиговых нагрузок, приведены графики изменения их значений при увеличении объемной концентрации стеклянных волокон, включений каучука и минерального порошка, состоящего из глинозема, графита и барита в равных объемных долях. Исследования показали, что при варьировании объемных содержаний включений любого типа значения компонент оператора концентрации значимо изменяются только для волокон бесщелочного стекла, ориентированных таким образом, что в них концентрация напряжений в материале наибольшая. При этом увеличение объемной доли включений каучука приводит к снижению указанных значений, а увеличение содержания включений других типов - к росту. Эпоксифенольная матрица удовлетворительно перераспределяет напряжения между включениями других типов, так как значения компонент 1111 и 1212 тензора концентрации напряжений в связующем близки к единице.
ТОРСИОННЫЕ ВОЛНЫ НА ПОВЕРХНОСТИ ПОЛОЙ ТРУБЫ С НЕОДНОРОДНЫМ ПОКРЫТИЕМ, "Наука Юга России"
Authors: Лыжов В.А. , Бочарова О.В. , Михайлова И.Б.
Published: August 2020

Исследована краевая задача о гармонических торсионных колебаниях полого упругого цилиндра стенка которого выполнена из функционально градиентного материала. Представленная в статье математическая модель допускает произвольную зависимость материальных параметров от радиуса цилиндра в частности, рассмотрены линейный, квадратичный, бикубический, обратно-пропорциональный, обратно-квадратичный законы. Функции изменения плотности и модуля сдвига материала стенки цилиндра могут отличаться друг от друга. Исследовано влияние различных видов изменения параметров стенки цилиндра на дисперсионные свойства и фазовые скорости первой и второй моды поверхностных волн. Проведено сравнение результатов, полученных для функционально-градиентных цилиндров, с результатами, полученными для однородного цилиндра с мягким или жестким покрытием. Анализ дисперсионных свойств и фазовых скоростей первой и второй мод поверхностных волн показал, что в случае жесткого покрытия фазовая скорость моды неоднородного цилиндра выше скорости соответствующей моды однородного цилиндра. Соответственно, в случае податливого покрытия скорость моды неоднородного цилиндра меньше скорости соответствующей моды однородного цилиндра. Эта закономерность одинаково проявляется как для различных видов функционально градиентных цилиндров, так и для однородного цилиндра с покрытием. Исследования показали, что интенсивность изменения скорости зависит от степени различия значений материальных параметров покрытия и основания или от вида функциональных зависимостей. Изменение скорости более всего выражено для акустически неоднородных тел. В случае акустически однородного цилиндра фазовая скорость каждой моды либо совпадает с соответствующей скоростью для однородного цилиндра, либо отличается от нее несущественно.
БИООПТИЧЕСКАЯ МОДЕЛЬ НИЖНЕГО ДОНА ДЛЯ ОЦЕНКИ КОНЦЕНТРАЦИИ ХЛОРОФИЛЛА Л ФИТОПЛАНКТОНА ПО ДИСТАНЦИОННОЙ СПЕКТРОМЕТРИЧЕСКОЙ ИНФОРМАЦИИ, "Наука Юга России"
Authors: Сухоруков Б. Л. , Решетняк Н.В. , Ковалева Г. Е.
Published: August 2020

По результатам дистанционных измерений спектров коэффициентов спектральной яркости (СКСЯ) и аналитических определений концентрации хлорофилла а фитопланктона в синхронно отобранных пробах воды за 2010-2016 гг. построена биооптическая модель (БОМ) Нижнего Дона. Съемки проводили современным спектрометром высокого спектрального разрешения в видимой области спектра. Значительная часть СКСЯ получена с такой удобной платформы, как мостовые переходы, с высоты около 30 м. Использованы данные, полученные как на речном участке этого водного объекта, так и на приплотинной части Цимлянского водохранилища и устьевом взморье Азовского моря. Для всего Нижнего Дона концентрация хлорофилла а фитопланктона, по данным аналитических определений, изменялась в пределах от 0,2 до 100,0 мг/м .В пределах среднеквадратичной погрешности около 8 мг/м3 БОМ Нижнего Дона не зависит от гидрологического сезона и может считаться единой. Обсуждены причины возможных отличий значений концентраций хлорофилла а фитопланктона, определенные различными методами. Однако даже с учетом этих отличий для целей оперативного мониторинга водных объектов оценка концентрации хлорофилла а фитопланктона по дистанционным спектрометрическим измерениям в реальном времени может оказаться более приемлемой, чем определение этого показателя в отбираемых пробах воды. Полученные результаты позволяют рекомендовать использовать оценку концентрации хлорофилла а фитопланктона по дистанционным спектрометрическим измерениям в реальном времени для решения задач оперативного мониторинга водных экосистем.
ЭСТУАРИИ АЗОВСКОГО МОРЯ - УНИКАЛЬНЫЕ ПОЛИГОНЫ ДЛЯ ИССЛЕДОВАНИЯ БИОКОРРОЗИИ. ОПЫТ ПОСТАНОВКИ ЭКСПЕРИМЕНТА, "Наука Юга России"
Authors: Матишов Г.Г. , Булышева Н.И. , Клещенков А.В. , Глущенко Г.Ю. , Варченко Е.А. , Гончаров А.А. , Гладких А.В.
Published: August 2020

С декабря 2018 г. в устьевой области р. Дон в зоне смешения речных и морских вод на стационарах Южного научного центра Российской академии наук - береговой научно-экспедиционной базе «Кагальник» и гидрометеопосту «Донской» - проводятся стендовые испытания по изучению совместного влияния климатических и биологических факторов на экспериментальные пластины, изготовленные из сталей марок 30ХГСА и СтЗ и алюминиевых сплавов марок АМгб и Д16. В этой акватории наблюдался достаточно агрессивный гидрологический режим, который характеризовался общим повышенным фоном солености (до 3-3,5 единиц практической солености) и низкими значениями температуры с частыми переходами через 0 °С с 20 декабря 2018 г. по 26 февраля 2019 г. и дальнейшим ростом температуры. В мае 2019 г. установился стабильный термохалинный режим. При исследовании формирования сообществ обрастания на экспериментальных пластинах для микроводорослей отмечен рост количественных характеристик с декабря по апрель, а затем его снижение. В течение всего периода наблюдений среди микрообрастаний доминировали диатомовые водоросли. Для макрообрастателей количественные показатели постепенно увеличиваются с декабря по июнь. Заселение пластин макробеспозвоночными началось со стали 30 ХГСА. По результатам трех месяцев испытаний наибольшая скорость коррозии отмечена на образцах всех марок на атмосферных стендах БНЭБ «Кагальник». При испытаниях в воде наибольшая скорость коррозии образцов сталей 30ХГСА и СтЗ была получена на станции БНЭБ «Кагальник», а наибольшая скорость коррозии образцов сплавов Д16 и АМгб - на станции ГМП «Донской». Оценка изменения твердости поверхности образцов металлических материалов показала наибольшее снижение данного показателя для образцов стали 30ХГСА - 17 % на атмосферном стенде, при испытаниях в воде снижение показателя составило 6,5 % независимо от станции экспонирования.
Genetic Analysis of Tilapia (Oreochromis niloticus) Nirwana Strain Cultured in Aceh Besar and Wanayasa by Using Random Amplified Polymorphic DNA Method
Authors: Yustiati Ayi , Hutagalung Reifolnanda Mangappu , Andriani Yuli , Lili Walim , Bangkit Ibnu
Published: August 2020

This research was carried out from June to November 2017. This research aims to analyze genetic relationship of tilapia (Oreochromis niloticus) nirwana strain which is cultured in Aceh Besar (Aceh Province) and in Wanayasa (West Java Province) with RAPD-PCR technique. The DNA Isolation Activity of tilapia nirwana strain was carried out in The Biotechnology Laboratory, Building No.4, FPIK UNPAD, Indonesia and the PCR process was carried out in The Microbiology and Biotechnology Laboratory, Building No.3 FPIK UNPAD, Indonesia. The purpose of this research is to determine the level of genetic relationship of tilapia nirwana strain cultured in Aceh Besar and Wanayasa and to find out whether tilapia nirwana strain in Aceh Besar can be used as a genetic stock. The results showed that genetic relationship level of tilapia nirwana strain cultured in Aceh Besar with those cultured in Wanayasa is 67%. The existence of environmental differences results in genetic diversity between Aceh Besar and Wanayasa tilapia nirwana strain. Factors that causing grouping movement are external factors such as: Geographical isolation and habitat fragmentation as well as internal factors such as mutation, natural selection, genetic drift, and gene flow. Tilapia nirwana strain that is cultured in Aceh Besar produce polymorphic bands, so it can be used as a new genetic stock to stabilize the tilapia nirwana strain production.
Protective Effect of Vitamin E on Potassium Dichromate-induced Haematoxicity and Oxidative Stress in African Catfish (Clarias gariepinus)
Authors: Azeez O. I. , Braimah S. F.
Published: August 2020

Effect of potassium dichromate was studied experimentally in African Catfish (Clarias gariepinus) with and without vitamin E in induced haematoxicity and oxidative stress. Blood samples were collected for haematology and plasma biochemical parameters while gills, liver and kidney samples were collected for evaluation of markers of oxidative stress. Exposure to potassium dichromate led to a significant decrease in PCV, RBC, haemoglobin concentration, MCV, MCH and total WBC when compared with the unexposed     control and those fed with vitamin E-supplemented feed. Nephrotoxicity was also observed as evidenced by increases in plasma creatinine levels. Exposure to potassium dichromate also led to increased oxidative stress as the concentrations of antioxidant endogenous enzymes - GPx, GST and GSH were depleted while potentiating lipid peroxidation and hydroxyl radical generation. The changes in the haematological, biochemical and antioxidant parameters were restored in the fish fed with vitamin E-supplemented feed. The study showed exposure to potassium dichromate to be toxic to African catfish, causing anaemia and kidney damage with free radical generation and depletion of GSH and other antioxidant defence system but the toxic effect can be minimised along with weight gain in fish supplemented by vitamin – E in aquaculture.
Effect of Residue Management and Cropping System on Direct Deeded Rice and System Productivity
Authors: Kumari Alisha , Kumar Vinod , Kumar Rajan , Kumar Mukesh
Published: August 2020

A field experiment was conducted during three seasons of 2018-19 at RPCAU, Pusa to evaluate the Effect of Residue Management and Cropping Systems on direct seeded rice and System productivity. Treatments comprised cropping systems in main plots: C1 - Rice - Wheat - Fallow, C2 - Rice - Wheat - Green Gram, C3 - Rice - Maize - Dhaincha, C4 - Rice - Maize + Potato - Dhaincha, C5 - Rice - Maize + Green Pea - Dhaincha and moisture regimes in sub plots with 3 days disappearance of ponded water in kharif season, three levels of IW/CPE ratio in rabi season I1 - IW/CPE = 0.6, I2 - IW/CPE = 0.8, I3 - IW/CPE = 1.0. Maximum number of tillers (273.55/m2), dry matter production (1464.91g/m2), number of panicles/m2 (267.80 m2), grain yield (52.21q/ha) of rice was observed in C5 cropping system and panicle length (23.99 cm cm), number of grains /panicle (160.05), straw yield (69.58 q/ha) in C4 which was  significantly superior than C1 cropping system. Plant height and 1000 grain weight, harvest index and Land Use Efficiency (LUE) were non significantly affected by different cropping systems. Maximum Rice Economic Yield (REY) of 24.26 t/ha and Production efficiency (PE) 73.97 kg/ha/day was observed in C4 which was significantly superior to rest of treatments. In sub plot maximum REY (15.905 t/ha) and PE (49.81 kg/ha/day) were observed in IW/CPE ratio 1 which was significantly superior to IW/CPE ratio 0.6 and 0.8.
Economic Supply and Demand with Data Analytics Functionalities
Authors: Gambo Richard C.
Published: August 2020

The primary goal of this article is to start a discussion about the possibility to connect supply and demand with data analytics functionalities in the frame of a dynamic system environment. So, a number of classical supply and demand topics, concepts, and definitions, as well as state-of-the-art data analytics concepts are reviewed firstly. Then, the critical modeling problem of both concepts “supply” and “demand” using system dynamics is introduced, analyzed, and examined. Finally, supply, demand, big data and data analytics are considered in a system dynamics modeling environment.

Actually, the proposed paper provides an initial approach (introduction) to the main (basic) procedures, analytical approaches and methods of data and big data analysis. In particular, a framework to help program staff in their job and approaches on supply and demand issues using big data procedures and methods is presented. Accordingly, this article aims to support the work of data analytics and statistics staff across various content areas with big data functionalities.

This article was created because the state-of-the-art concept “using data and information in meaningful and smart ways” includes many opportunities and possibilities and obviously a great deal of information is involved. Doubtless, some of this information has a great complexity and it is highly dependent upon specialized data, information and knowledge like the “data analytics” concept. However, there are many ways of “using data in smart ways” that are more primitive and that involve relatively simple enough procedures.

Hence, the purpose of the current paper is to provide data analytics functionalities in supply and demand applications with a contemporary framework for thinking about, working with, and benefiting from an increased ability to use big data smartly and efficiently.

Finally, the current paper should be characterized as a knowledge generation opinion article which recommends the inclusion of data analytics and distributed technology in supply and demand industry in order to enhance functionalities and compatibility to state-of-the-art ICT.
A dimensão regional na formação da vida cultural no Meio Norte
Authors: Dantas Filho Alberto Pedrosa
Published: August 2020

Pesquisa sobre as bases econômicas, sociais e culturais comuns entre os atuais estados do Maranhão e do Piauí e as demandas infraestruturais envolvidas na formação de vida citadina. É feita segmentação historiográfica em dois períodos respeitantes à fase luso-americana e à anexação do território piauiense ao Maranhão.  Propõe-se como base epistemológica a segmentação histórica e qualitativa em quatro períodos. Estabelecimento de componentes históricas relativas à anexação do território do Piauí ao Maranhão, formação da economia agroexportadora do gado, processo de migração, formação das cidades ribeiras e o papel exercido pelos rios da sub-região Meio Norte na dinâmica de circularidades entre os municípios com reflexos na formação da vida musical. Conclui-se que o processo histórico do Meio Norte repercute na atualidade musical dos dois estados. 
Ao Prof. Jamary Oliveira, a gratidão e o reconhecimento da Escola de Música da UFBA
Authors: Brandão José Maurício Valle
Published: August 2020

Homenagem da Escola de Música da UFBA ao professor Jamary Oliveira, falecido em  29 de abril de 2020
Evolution de la composition lipidique de Nocardia asteroides au cours de la croissance
Authors: Bordet C. , Vacheron M.J. , Michel G.
Published: July 2002

By addition of 1‐14C‐sodium acedate to the growth medium of Nocardia asteroides, it can be shown that the lipid content increases during the exponential phase, but does not vary during the stationary phase of the growth. Nocardic acid biosynthesis from the medium molecular weight fatty acids occurs chiefly during te stationary phase. As these compounds are localised in the cell walls, it becomes evident that the lipid envelope of the walls is still increasing when the cell growth and division have stopped.
Nachweis eines enzymgebundenen Zwischenprodukts bei der Umwandlung von Thymidindiphosphat‐D‐glucose in Thymidindiphosphat‐L‐rhamnose in E. coli B
Authors: Lehmann J. , Pfeiffer E.
Published: July 2002

An incubation mixture of TDP‐D‐glucose and a purified enzyme extract from E. coli B containing TDP‐D‐glucose 4,6‐hydro‐lyase was treated with NaB3H4. Hydrolysis of the separated sugar nucleotide fraction yielded D‐galactose‐4‐3H but no 3H‐labelled D‐glucose. This indicates the presence of TDP‐4‐keto‐D‐glucose as an intermediate in the enzymatic conversion of TDP‐D‐glucose to TDP‐L‐rhamnose. The stereospecifity of the NaB3H4 reduction can only be explained if TDP‐4‐keto‐D‐glucose exists as an enzyme bound complex.
Formation of coenzyme a esters of cinnamic acids with an enzyme preparation from cell suspension cultures of parsley
Authors: Hahlbrock K. , Grisebach H.
Published: July 2002

The formation of coenzyme A thiol esters of cinnamic, p‐coumaric, p‐methoxy cinnamic, and ferulic acids was catalyzed by enzyme preparations from cell suspension cultures of leaf petioles from parsley (Petroselinum hortense Hoffm.). Of these acids, p‐coumaric acid served as the most efficient substrate. Enzyme activity is markedly increased upon illumination with white light in a manner very similar to that in which the activities of a number of enzymes involved in flavone biosynthesis are stimulated by light. This strongly suggests that the formation of p‐coumaroyl coenzyme A is part of this biosynthetic pathway.
Dissociation of 70 S E. coli ribosomes induced by a ribosomal factor (DF). Electrophoretic studies of the ribosomal particles
Authors: J. Talens  , Kalousek F. , Bosch L.
Published: July 2002

The dissociation of purified 70 S.E. coli ribosomes, induced by the dissociation factor DF, has been studied by submitting the reaction mixtures to electrophoresis on polyacrylamide gels. The electrophoretic analysis of the ribosome mixtures revealed a heterogeneity which escaped detection by conventional sucrose gradient centrifugation. Increasing amounts of DF in the reaction mixtures converted 70 S ribosomes to particles (designated 70 S (I)) which migrate slower in the electric field than the original 70 S ribosomes. These 70 S (I) ribosomes still consist of both subunits. They dissociate upon further raising the DF concentration.
Proprietes cinetiques de la dopamine‐β‐hydroxylase membranaire
Authors: Miras Portugal Maria Teresa , Jorda Antonio , Ruiz Angel Santos
Published: July 2002

We studied membrane bound dopamine‐β‐hydroxylase (DBH) from chromaffin granules, in order to determine whether a biological form of immobilization of the enzyme altered its kinetic properties. The results obtained suggested that DBH either in soluble or solubilized form showed a ping‐pong mechanism whereas the membrane bound DBH did not. Affinity for the substrate and the pH stability were lower in soluble or solubilized form than in membrane bound DBH.
Identification of glycoproteins bearing human blood group A determinants in rabbit enterocyte plasma membranes
Authors: Gorvel J.P. , Wisner-Provost A. , Maroux S.
Published: July 2002

A‐antigenicity; Glycocalyx; Hydrolases; Membrane glycoproteins
Effect of b‐itc1‐site inhibitors on the midpoint potentials of mitochondrial cytochromes b
Authors: Kunz Wolfram S. , Konstantinov Alexander A.
Published: July 2002

Anaerobic potentiometric titrations of b cytochromes have been carried out in beef heart submitochondrial particles in the presence of several specific inhibitors of electron transfer through the b‐c
1‐site of the respiratory chain. Whereas antimycin shows no significant effect on the titration curve of cytochrome b‐562, NoHOQnO is found to shift the E
m of b‐562 by 20–30 mV to the positive. Funiculosin raises the E
m of b‐562 by > 100 mV and also appears to bring about a minor shift of b‐566 midpoint potential. In the presence of myxothiazol, both b cytochromes with E
m values 15–30 mV more positive than in the control.
Role of the quinone structure in the mitochondrial damage induced by antitumor anthracyclines
Authors: Pollakis Georges , Goormaghtigh Erik , Ruysschaert Jean-Marie
Published: July 2002

Adriamycin cardiotoxicity has been correlated with a disturbance of heart mitochondrial functions. Here, 5‐iminodaunorubicin was compared with adriamycin for its capability to interfere in the mitochondrial electron transport with subsequent membrane damaging. The results suggest that minor chemical modifications of the anthraquinone moiety of anthracycline glycoside drugs should be a promising way to decrease mitochondrial membrane damage induced by this class of antitumor drugs.
Covalent attachment of aspartic acid to yeast aspartyl‐tRNA synthetase induced by the enzyme
Authors: Lorber B. , Kern D. , Giegé R. , Ebel J.-P.
Published: July 2002

Aspartic acid can be covalently linked to yeast aspartyl‐tRNA synthetase and to other proteins, in the absence of tRNA, under conditions where the synthetase activates the amino acid into aspartyl‐adenylate, i.e., in the presence of ATP and MgCl2. The linkage between aspartic acid and the protein is acid and alkali resistant; thus it is likely a peptide‐like amide bond formed between the activated carboxylate group of aspartic acid and the primary amine function of the side chain of lysine residues.
Differential effect of phenobarbital and β‐naphthoflavone on the mRNAs coding for cytochrome P450 and NADPH cytochrome P450 reductase
Authors: Shephard Elizabeth A. , Phillips Ian R. , Pike Susan F. , Ashworth Alan , Rabin Brian R.
Published: July 2002

The induction in rat liver of a specific variant(s) of cytochrome P450 (PB‐P450) by phenobarbital and its repression by β‐naphthoflavone occur through corresponding changes in the levels of mRNA coding for the protein(s). The level of translatable mRNA coding for NADPH‐cytochrome P450 reductase in rat liver increases on treatment with phenobarbital but not β‐naphthoflavone.
Different polypeptides of bovine heart cytochrome c oxidase are in contact with cytochrome c
Authors: Bisson Roberto , Montecucco Cesare
Published: July 2002

Two water‐soluble carbodiimides, differing in molecular dimensions, have been used to characterize the cytochrome c binding site of bovine heart cytochrome c oxidase. Several polypeptide components of the enzyme contain acidic residues which are modified by these reagents. Carboxyl groups present in subunit II, VII and polypeptide c, are protected from modification when cytochrome c, equimolar to oxidase, is added and they can cross‐link to the substrate once activated by the carbodiimide. Comparison of the modification patterns suggest that the most reactive residues are located on subunit II and VII, the former being also more exposed. The data obtained indicate that eventhough subunit II plays the major role in binding cytochrome c, at least two other lower M
r polypeptides contribute to the cytochrome c binding domain.
Purification of complement components by hydrophobic affinity chromatography on phenyl—Sepharose
Authors: Al Salihi A. , Ripoche J. , Pruvost L. , Fontaine M.
Published: July 2002

Human complement components C5 and C3 were purified with 41% and 20% yields, respectively, by euglobulin precipitation, DEAE—Sephacel ion‐exchange chromatography and gel filtration. Phenyl—Sepharose chromatography allowed the complete separation of C3 and C5. C3 bound loosely on the resin whereas C5 bound firmly and was eluted with 50% glycerin solution. Gel filtration on Sephacryl S‐300 allowed the depletion of C4bp and H that contaminated C5 preparations. Homogeneity of C5 and C3 preparations was demonstrated by SDS—PAGE and immunochemical analysis. C5 and C3 consisted of two chains (α, 110000; β, 75000) linked by disulfide bridges.
Alternative hypotheses of proton ejection in cytochrome oxidase vesicles
Authors: Mitchell Peter , Moyle Jennifer
Published: July 2002

A review of published experimental and interpretative knowledge concerning proton ejection associated with cytochrome c oxidation by artificial phospholipid vesicles inlaid with cytochrome c oxidase indicates that the detailed characteristics of the redox‐linked proton ejection cannot be simply explained by proton pumping. We propose an alternative hypothesis according to which proton ejection is due to the redoxlinked deprotonation of a complex involving phospholipid and cytochrome c at the surface of the vesicles. The postulates upon which this hypothesis depends are explicitly outlined, and some methods of testing the hypothesis are suggested.
Autophosphorylation of cGMP‐dependent protein kinase is stimulated only by occupancy of one the two cGMP binding sites
Authors: Hofmann Franz , Gensheimer Hans-Peter , Gobel Claus
Published: July 2002

cGMP‐Dependent protein kinase contains, per subunit, 2 binding for cGMP. The apparent K
D values for site 1 and 2 were 12 and 55 nM. The analogues 8‐benzyl‐amino‐cAMP and N
2‐monobutyryl‐cGMP bind preferentially to site 1 and 2, respectively. Both analogues stimulate autophosphorylation of the enzyme at concentrations at which only half of the phosphotrasferase activity of the enzyme is expressed. Complete expression of the phosphotransferase activity requires a high concentration of each analogue and is accompanied by inhibition of the autophosphorylation reactions. It is concluded that occupancy of site 1 or 2 stimulates autophosphorylation while occupancy of both sites prevents autophosphorylation.
Isolation and characterization of the Co‐methyl and Co‐aquo derivative of 5‐hydroxybenzimidazolylcobamide (factor III) from Methanosarcina barkeri grown on methanol
Authors: Höllriegl Ver , Scherer Paul , Renz Paul
Published: July 2002

The Co‐methyl and the Co‐aquo derivative of 5‐hydroxybenzimidazolylcobamide (factor III) were isolated as the major natural corrinoids from Methanosarcina barkeri ‘Fusaro’. They were characterized by their UV/VIS‐spectra, their chromatographic behaviour, and their electrophoretic properties. The portion of Co‐methyl‐factor III was found to be 70–80% whereas Co‐aquo‐factor III contributed 20–30% to the total amount of corrinoids.
Interactions of the 26–39 fragment of the cro protein from λ bacteriophage with nucleic acids
Authors: Mayer R. , Lancelot G. , Hélène C.
Published: July 2002

A tetradecapeptide with a sequence identical to residues 26–39 of the cro protein from bacteriophage λ has been synthesized. This peptide has no secondary structure in an aqueous buffer but adopts an α‐helical conformation in the presence of 20% hexafluoroisopropanol. The fluorescence of the single tyrosyl residue of the cro protein fragment is quenched upon binding to nucleic acids. Proton magnetic resonance has been used to investigate complex formation of the cro protein fragment with a self‐complementary decadeoxynucleotide d(AATTGCAATT). Changes in resonance positions and linewidths have been observed for both partners in the 4 complexes which are obtained when either the single‐stranded or double‐standard oligonucleotide is mixed with either the random coil or the α‐helical peptide. These studies are presently extended to the specific complex formed by the cro protein fragment with the OR3 operator sequence.
Selective cleavage of the connector segments within the myosin‐S1 heavy chain by staphylococcal protease
Authors: Chaussepied P. , Bertrand R. , Audemard E. , Pantel P. , Derancourt J. , Kassab R.
Published: July 2002

The existence of the two connector segments linking the tryptic 50 kDA fragment of skeletal S1 heavy chain to the adjacent 27 kDa and 20 kDa peptides was ascertained by digestion of S1 with staphylococcal protease which was found to act specifically at these particular regions. Three new peptides of M
r 28 000, 48 000 and 22 000 were produced and the novel S1 derivative formed had an intact actin‐activated ATPase activity. Amino acid sequence analyses indicated that the 48 kDa and 22 kDa peptides overlap the two connector elements.
Soluble phorbol ester binding sites and phospholipid‐ and calcium‐dependent protein kinase activity in cytosol of chick oviduct
Authors: Gschwendt M. , Horn F. , Kittstein W. , Fürstenberger G. , Marks F.
Published: July 2002

A large amount of specific high affinity binding sites for tumor promoting phorbol esters as well as of a Ca2+‐ and phospholipid‐dependent protein kinase is present in cytosol of chick oviduct. 12‐O‐Tetradecanoyl‐phorbol‐13‐acetate (TPA) is able to replace either Ca2+ or the phospholipid phosphatidylserine as activators of the kinase to some extent. The maximum activity of the enzyme in the presence of Ca2+ and phosphatidylserine, however, cannot be increased further by TPA. Various second stage tumor promoters also exhibit the capacity to stimulate the protein kinase, whereas the non‐promoting phorbol ester 4‐O‐methyl‐TPA, as well as the non‐promoting, but with respect to other responses TPA‐like, calcium ionophore A23187, do not affect the kinase.
Amino acid sequence of the oligomycin sensitivity‐conferring protein (OSCP) of beef‐heart mitochondria and its homology with the δ‐subunit of the F1‐ATPase of Escherichia coli
Authors: Ovchinnikov Y.A. , Modyanov N.N. , Grinkevich V.A. , Aldanova N.A. , Trubetskaya O.E. , Nazimov I.V. , Hundal T. , Ernster L.
Published: July 2002

The complete amino acid sequence of the oligomycin sensitivity‐conferring protein (OSCP) of beef‐heart mitochondria is reported. The protein contains 190 amino acids and has a molecular mass of 20 967. Its structure is characterized by a concentration of charged amino acids in the two terminal segments (N 1–77 and C 128–190) of the protein, whereas its central region is more hydrophobic. The earlier reported homology of the protein with the δ‐subunit of E. coli F1, based on the terminal amino acid sequences of OSCP, is further substantiated.
A Ca2+‐dependent actin modulator from vertebrate smooth muscle
Authors: Hinssen H. , Small J.V. , Sobieszek A.
Published: July 2002

A protein of M
r ≈ 85 000 has been isolated and purified from pig stomach smooth muscle that modulates the polymer state of actin in a Ca2+‐dependent manner. When added either to preformed F‐actin filaments or to G‐actin, prior to polymerisation, the modulator induces the formation of shorter filaments. The average filament length in the presence of the modulator is directly dependent on its molar ratio to actin indicating a stoichiometric rather than a catalytic type of interaction. When mixed with G‐actin the modulator forms a stable complex with two actin monomers; this complex is presumed to act as a potent nucleus for actin polymerisation. The dynamics of the interaction with F‐actin suggests a direct severing of actin filaments by the modulator via a binding to intrafilamentous actins.
The glycoprotein 71 of ecotropic Friend murine leukemia virus
Authors: Schlüter Michael , Linder Dietmar , Geyer Rudolf , Hunsmann Gerhard , Schneider Josef , Stirm Stephan
Published: July 2002

The glycoprotein from Friend murine leukemia virus was digested with protease from Staphylococcus aureus V8. A glycopeptide comprising the N‐terminal glycosylation site (Asn‐12) was isolated from the mixture of fragments and analyzed by amino acid sequencing and methylation‐capillary gas chromatography—mass spectrometry before and after treatment with sialidase from Vibrio cholerae. Asn‐12 was thus found to be substituted by a family of partially sialylated, fucosylated, and intersected glycoprotein N‐glycans of the hybrid type.
Ionic regulation of cyclic AMP levels in Paramecium tetraurelia in vivo
Authors: Schultz Joachim E. , Grünemund Ruth , von Hirschhausen Reginhard , Schönefeld Ulrich
Published: July 2002

cAMP levels in Paramecium increased dose dependently after a step increase of [Ca] or [Sr] in the incubation, provided K was present. Two mM Ca or Sr tripled cAMP concentrations within 3 s and induced an increase in forward swimming speed. The increase in cAMP formation was strictly dependent on the Donnan ratio . Na, Li, or tetraethylammonium could not replace K. The data provide evidence for regulation of cAMP in Paramecium by the membrane surface charge as determined specifically by the K:Ca ratio.
Alternate domains of neuron DNA topoisomerase I in developing rat brain
Authors: Ivanov Vladimir A. , Melnikov Anatolij A.
Published: July 2002

Developing brain
Nerve cell chromatin
DNA topoisomerase
RNA‐binding protein kinase from amphibian oocytes is a casein kinase II
Authors: Kandror K.V. , Stepanov A.S.
Published: July 2002

RNA‐binding protein kinase from amphibian oocytes modifies serine and threonine residues in the molecules of substrates and utilizes both ATP and GTP. Low concentrations of heparin inhibit protein kinase. The foregoing suggests that this enzyme is casein kinase II. It is shown that RNA‐binding proteins lack active forms of phosphatases and proteases which may affect the results of phosphorylation of both endogenous and exogenous substrates.
Structure of the rat pro‐opiomelanocortin (POMC) gene
Authors: Drouin Jacques , Chamberland Michel , Charron Jean , Jeannotte Lucie , Nemer Mona
Published: July 2002

The gene encoding pro‐opiomelanocortin (POMC) presents unique regulatory features. In particular, glucocorticoids inhibit transcription of the POMC gene in the anterior pituitary, but not in the intermediate pituitary. In order to study the mechanism leading to transcriptional inhibition of POMC by glucocorticoid and the interaction of the glucocorticoid receptor complex with specific DNA sequences along the POMC gene, we have cloned the rat POMC gene and determined its structure. The gene is composed of three exons and appears to be present at a single copy per haploid genome. Besides the usual regulatory signals like ‘TATA’ and ‘CCAAT’ boxes, the upstream region contains sequences homologous to known enhancer sequences and to the glucocorticoid receptor binding site observed in glucocorticoid‐responsive genes.
Kinetics of dark proton efflux in chloroplasts
Authors: Schönfeld Mordechay , Kopeliovitch Bente Sloth
Published: July 2002

The rate constant for dark proton efflux from preilluminated chloroplasts, was found to be proportional to the proton permeability, and inversely proportional to the ‘proton binding capacity’ of the thylakoids (the ratio between bound and free protons). Dark proton efflux was resolved into two kinetically distinct components: a diffusion‐mediated process which was predominant below pH 7, and a separate leakage pathway, characterized by linear dependence on the internal to external proton concentration ratio, which was predominant above pH 7. An increased proton‐binding capacity accompanied the increased proton permeability associated with this second pathway.
Mechanisms underlying the asynchronous replacement of myosin light chain isoforms during stimulation‐induced fibre‐type transformation of skeletal muscle
Authors: Brown Wendy E. , Salmons Stanley , Whalen Robert G.
Published: July 2002

During the fibre‐type transformation induced by chronic electrical stimulation of rabbit fast‐twitch muscle, replacement of the fast forms of the two classes of myosin light chain by their slow isoforms occurs asynchronously. Studies of total cellular myosin light chains and of the slow‐to‐fast transition now justify the conclusion that the asynchrony is due to switching between the expression of fast and slow genes for the two light chain classes at sequential stages of the transformation process.
Expression of genes for subunits of plant‐type RuBisCO from Chromatium and production of the enzymically active molecule in Escherichia coli
Authors: Viale Alejandro M. , Kobayashi Hirokazu , Takabe Tetsuko , Akazawa Takashi
Published: July 2002

A DNA fragment containing genes for both large (A) and small (B) subunits ofribulose‐1,5‐bisphosphate carboxylase/oxygenase (RuBisCO) from a photosynthetic bacterium Chromatium vinosum was ligated with vectors for expressing unfused proteins and introduced into cells of Escherichia coli. The expressers of RuBisCO were screened on agar plates using the specific antibody raised against the native enzyme from Chromatium. The production of both subunits A and B in the expressers was demonstrated by an immunoblotting experiment. The amount of RuBisCO produced in the E. coli cells was as high as 15% of the total soluble protein after induction with isopropyl‐β‐D‐thiogalactoside. The specific activity of enzyme molecules produced in E. coli was nearly the same as that of the original Chromatium enzyme. On gel filtration high‐performance liquid chromatography the two enzymes showed identical elution behavior, strongly indicating their similar quaternary structures.
Parallel inactivation of α2‐adrenergic agonist binding and Ni by alkaline treatment
Authors: Kim Marian H. , Neubig Richard R.
Published: July 2002

α2‐Adrenergic receptor‐mediated inhibition of adenylate cyclase requires the guanine nucleotide‐binding protein, Ni. This protein may also be required for stabilization of high‐affinity α2‐adrenergic agonist binding. Human platelet membranes treated under alkaline conditions (pH 11.5) exhibited a selective loss of high‐affinity agonist binding as measured by P‐[3H]aminoclonidine and [3H]UK 14,304. Binding of the antagonist [3H]yohimbine was largely unaffected with retention of > 60% of control binding sites. Ni determined by pertussis toxin‐catalyzed [32P]ADP‐ribosylation of cholate extracts from alkaline‐treated membranes, was also markedly reduced. The parallel loss of of α2‐agonist binding and Ni provides additional evidence that Ni, is required for α2‐adrenergic agonist binding.
The tryptic and chymotryptic fragments of the β‐subunit of guanine nucleotide binding proteins in brain are identical to those of retinal transducin
Authors: Pines Mark , Gierschik Peter , Spiegel Allen
Published: July 2002

The 35‐kDa β‐subunit of transducin purified from rod outer segment membranes is cleaved into 2 major fragments by trypsin, and 7 major fragments by chymotrypsin. Identical fragments are visualized by immunoblotting with transducin‐β specific antisera after proteolysis of rod outer segment membranes, purified brain guanine nucleotide binding proteins, and brain membranes. The results indicate that the β‐subunits of transducin and of brain guanine nucleotide binding proteins are not only similar structurally, but are also similarly oriented in membranes with respect to accessibility to proteolytic enzymes.
A distinct ferredoxin for nitrogen fixation isolated from heterocysts of the cyanobacterium Anabaena variabilis
Authors: Schrautemeier Bernhard , Böhme Herbert
Published: July 2002

Ferredoxin from heterocysts of Anabaena variabilis has been isolated and its biological activity compared to ferredoxin obtained from vegetative cells of the same organism. Both ferredoxins catalyze equally effective NADP+ photoreduction by heterocyst thylakoids. When photoreduced, both ferredoxins transfer electrons to nitrogenase from A. variabilis, with heterocyst ferredoxin being twice as active as vegetative cell ferredoxin. In the dark, however, only heterocyst ferredoxin is able to link reducing power, generated by soluble systems, such as H2/hydrogenase (from Clostridium pasteurianum) and NADPH/ferredoxin:NADP+ oxidoreductase (from A. variabilis), to the cyanobacterial nitrogenase. Using heterocyst homogenates with glucose 6‐phosphate as electron donor, only ferredoxin from heterocysts is able to stimulate nitrogenase activity further.
An exposed tyrosine residue of RNase T1 and its involvement in the interaction with guanylic acid
Authors: Nagai Hiroshi , Kawata Yasushi , Hayashi Fumiaki , Sakiyama Fumio , Kyogoku Yoshimasa
Published: July 2002

A photo‐CIDNP spectrum of RNase T1 showed that 4 out of the total 9 tyrosines are accessible to the photosensitive dye, while none of the histidine and tryptophan residues are accessible. By comparison with the results of nitration of tyrosine side chains followed by peptide analysis, it can be concluded that Tyr 45 is mostly exposed on the surface of RNase T1. On addition of 2'‐GMP, the signal of Tyr 45 shifts upfield and is remarkably broadened, which suggests that the phenyl ring of Tyr 45 stacks on the guanine ring of 2'‐GMP. Similar phenomena were observed on addition of 3'‐GMP and 3'‐dGMP.