СИМПОЗИУМ ПАМЯТИ АКАДЕМИКА Н.А. ЛОГАЧЕВА «КАЙНОЗОЙСКИЙ КОНТИНЕНТАЛЬНЫЙ РИФТОГЕНЕЗ», ИРКУТСК, РОССИЯ, 7–11 ИЮНЯ 2010 Г.

The information on the «Cenozoic Continental Rifting» Symposium dedicated to the memory of Academician N.A. Logachev is presented. It was held on June 7–11, 2010 at the Institute of the Earth’s Crust, Irkutsk. The scope of conference is presented.Представлена информация о симпозиуме памяти академика Н.А. Логачева «Кайнозойский континентальный рифтогенез», состоявшемся 7–11 июня 2010 г. в Институте земной коры СО РАН (г. Иркутск). Освещена тематика конференции

Isolation, characterization and molecular cloning of Duplex-Specific Nuclease from the hepatopancreas of the Kamchatka crab

<p>Abstract</p> <p>Background</p> <p>Nucleases, which are key components of biologically diverse processes such as DNA replication, repair and recombination, antiviral defense, apoptosis and digestion, have revolutionized the field of molecular biology. Indeed many standard molecular strategies, including molecular cloning, studies of DNA-protein interactions, and analysis of nucleic acid structures, would be virtually impossible without these versatile enzymes. The discovery of nucleases with unique properties has often served as the basis for the development of modern molecular biology methods. Thus, the search for novel nucleases with potentially exploitable functions remains an important scientific undertaking.</p> <p>Results</p> <p>Using degenerative primers and the rapid amplification of cDNA ends (RACE) procedure, we cloned the Duplex-Specific Nuclease (DSN) gene from the hepatopancreas of the Kamchatka crab and determined its full primary structure. We also developed an effective method for purifying functional DSN from the crab hepatopancreas. The isolated enzyme was highly thermostable, exhibited a broad pH optimum (5.5 – 7.5) and required divalent cations for activity, with manganese and cobalt being especially effective. The enzyme was highly specific, cleaving double-stranded DNA or DNA in DNA-RNA hybrids, but not single-stranded DNA or single- or double-stranded RNA. Moreover, only DNA duplexes containing at least 9 base pairs were effectively cleaved by DSN; shorter DNA duplexes were left intact.</p> <p>Conclusion</p> <p>We describe a new DSN from Kamchatka crab hepatopancreas, determining its primary structure and developing a preparative method for its purification. We found that DSN had unique substrate specificity, cleaving only DNA duplexes longer than 8 base pairs, or DNA in DNA-RNA hybrids. Interestingly, the DSN primary structure is homologous to well-known Serratia-like non-specific nucleases structures, but the properties of DSN are distinct. The unique substrate specificity of DSN should prove valuable in certain molecular biology applications.</p

МИОЦЕНОВЫЙ И ДЕВОНСКИЙ МАГМАТИЗМ В СОЧЛЕНЕНИИ ТУВИНО-МОНГОЛЬСКОГО МАССИВА И СИБИРСКОГО КРАТОНА: ОБЩИЙ КОМПОНЕНТ МАНТИЙНЫХ ИСТОЧНИКОВ И ЕГО ПРОИСХОЖДЕНИЕ

Devonian dikes of the Urik-Belaya and Shagayte-Gol-Urik zones and Miocene lavas of the Urik volcanic field are spatially associated with each other at the structural junction between the Neoproterozoic Tuva-Mongolian massif and Siberian craton. The former dike belt is represented by basalts and basaltic andesites of tholeiitic series and the latter one by trachybasalts, trachyandesitic basalts of moderately alkaline series and trachybasalts, phonotephrites of highly alkaline one. The Urik volcanic field is composed of trachybasalts and trachyandesitic basalts of moderately alkaline series. A partial similarity between magmatic series of different age is found in terms of major oxides, trace elements, and Sr, Pb isotopes. The common component corrected for age was defined through its converging mixing trends with those of the lithospheric mantle and crust. The component identification was a basis for deciphering the nature of isotopic and geochemical heterogeneity of evolved magmatic sources. It was inferred that the common component characterizes either a modified (depleted) reservoir of the lower mantle or, more likely, a local region of the convecting asthenospheric mantle that underlies the Tuva-Mongolian massif. The latter interpretation assumes the formation of a locally convecting asthenosphere in the middle Neoproterozoic, along with the development of the Oka zone at the massif, and puts constrains on later sufficient processing of the asthenosphere due to rising plumes or subducting slabs.В структурном сочленении неопротерозойского Тувино-Монгольского массива с Сибирским кратоном пространственно совмещены между собой девонские дайки Урик-Бельского и Шагайтэ-Гол-Урикского поясов и миоценовые лавы Урикского вулканического поля. Первый дайковый пояс представлен базальтами-андезибазальтами толеитовой серии, второй – трахибазальтами-трахиандезибазальтами умереннощелочной серии с локальным распространением трахибазальтов-фонотефритов серии повышенной щелочности. Урикское вулканическое поле образуют трахибазальты-трахиандезибазальты умереннощелочной серии. Выявлено частичное сходство концентраций петрогенных оксидов, микроэлементов и изотопных отношений стронция и свинца разновозрастных магматических серий. С поправкой на возраст определен общий компонент магматических расплавов по сходящимся трендам его смешения с компонентами мантийной части литосферы и коры. Идентификация компонента послужила основой для расшифровки характера изотопно-геохимической гетерогенности разновозрастных магматических источников. Сделан вывод о том, что общий компонент характеризует либо модифицированный (обедненный) нижнемантийный резервуар, либо, что более вероятно, локальную область конвектирующей астеносферной мантии, подстилающей Тувино-Монгольский массив. В последней интерпретации допускается образование локального конвектирующего объема астеносферы в середине неопротерозоя, одновременно с заложением и развитием Окинской зоны массива, и накладываются ограничения на последующие существенные преобразования астеносферы под влиянием поднятия плюмового или погружения слэбового материала

ВЫСОКОМАГНЕЗИАЛЬНЫЕ ЛАВЫ ДАРИГАНСКОГО ВУЛКАНИЧЕСКОГО ПОЛЯ, ЮГО-ВОСТОЧНАЯ МОНГОЛИЯ: ПЕТРОГЕНЕТИЧЕСКАЯ МОДЕЛЬ МАГМАТИЗМА НА АСТЕНОСФЕРНО-ЛИТОСФЕРНОЙ ГРАНИЦЕ

It is revealed that high-Mg lavas (MgO=11.0–15.8 wt. %) are spatially controlled by linear zones extending for more than 90 km and demonstrate chemically distinct differences from moderately-Mg compositions (MgO=3.0–11.0 wt. %), which occupy the isometric area of the Dariganga volcanic field. From the major and trace-element data on the rocks in the field under study, we have justified a petrogenetic mode of the uniform one-level mantle magmatism. Our model differs from the contrasting magmatism model of the processes that developed at two levels beneath the Hannuoba volcanic field. Based on tomography images showing the East Mongolian local low-velocity anomaly in the upper mantle, we suggest that magmatism of Type 1 occurred in the mantle sources at the asthenosphere–lithosphere boundary and the underlying asthenosphere as a reflection of a relatively weak mantle flow that may have ascended from a depth of ~250 km. Magmatism of Type 2 occurred in the isolated sources of the sublithospheric mantle and the asthenosphere–lithosphere boundary as an evidence on the initially strong mantle flow that may have ascended from a depth of ~410 km.Установлен пространственный контроль высокомагнезиальных вулканических пород (MgO=11.0–15.8 мас. %) линейными зонами протяженностью более 90 км и резкие отличия их химического состава от умеренно-магнезиальных (MgO=3.0–11.0 мас. %) пород, занимающих всю изометричную территорию вулканического поля Дариганга. При сравнительном анализе петрогенных и малых элементов пород этого поля обоснована петрогенетическая модель мантийного магматизма одного глубинного уровня, в отличие от модели контрастных магматических процессов, проявленных на двух глубинных уровнях под вулканическим полем Ханнуоба. С учетом томографических данных о наличии Восточно-Монгольской низкоскоростной аномалии в верхней мантии, предполагается, что магматизм первого типа получил развитие в источниках на границе астеносферы–литосферы и непосредственно нижележащей астеносферы как отражение относительно слабого мантийного потока, вероятно, поднимавшегося с глубины ~250 км. Магматизм второго типа возник в обособленных источниках подлитосферной мантии и границы астеносферы–литосферы как свидетельство изначально сильного мантийного потока, возможно, зародившегося на глубине ~410 км

АКАДЕМИК Н.А. ЛОГАЧЕВ И ЕГО НАУЧНАЯ ШКОЛА: ВКЛАД В ИЗУЧЕНИЕ КАЙНОЗОЙСКОГО КОНТИНЕНТАЛЬНОГО РИФТОГЕНЕЗА

N.A. Florensov and N.A. Logatchev pioneered development of fundamental concepts of the structure and evolution of the Baikal system of rift basins. At the turn to the 21st century, in view of the wide availability of scientific research data on the Cenozoic continental rift zones located in Eurasia, Africa and North America, and taking into account the application of new research methods and options to process and analyze huge amounts of geological and geophysical data, a priority was comprehensive modeling of rifting from its origin to the current period of time. This scientific challenge was addressed by the research team under the leadership of N.A. Logachev.Фундаментальные представления о строении и развитии Байкальской системы рифтовых впадин были заложены в трудах Н.А. Флоренсова и Н.А. Логачева. Высокая степень изученности кайнозойских континентальных рифтовых зон Евразии, Африки и Северной Америки, а также новые методики и возможности обработки и анализа больших массивов геологической и геофизической информации выдвинули на рубеже XX и XXI столетий в качестве приоритетной задачи создание комплексной модели развития рифтогенеза с его зарождения до современности. Решение поставленной задачи осуществлялось в рамках работ научной школы под руководством Н.А. Логачева

CENOZOIC CONTINENTAL RIFTING SYMPOSIUM DEDICATED TO THE MEMORY OF ACADEMICIAN N.A. LOGATCHEV, IRKUTSK, RUSSIA, JUNE 7–11, 2010

The information on the «Cenozoic Continental Rifting» Symposium dedicated to the memory of Academician N.A. Logachev is presented. It was held on June 7–11, 2010 at the Institute of the Earth’s Crust, Irkutsk. The scope of conference is presented

HIGH-MG LAVAS FROM THE DARIGANGA VOLCANIC FIELD IN THE SOUTHEASTERN MONGOLIA: PETROGENETIC MODEL OF MAGMATISM AT THE ASTHENOSPHERE–LITHOSPHERE BOUNDARY

It is revealed that high-Mg lavas (MgO=11.0–15.8 wt. %) are spatially controlled by linear zones extending for more than 90 km and demonstrate chemically distinct differences from moderately-Mg compositions (MgO=3.0–11.0 wt. %), which occupy the isometric area of the Dariganga volcanic field. From the major and trace-element data on the rocks in the field under study, we have justified a petrogenetic mode of the uniform one-level mantle magmatism. Our model differs from the contrasting magmatism model of the processes that developed at two levels beneath the Hannuoba volcanic field. Based on tomography images showing the East Mongolian local low-velocity anomaly in the upper mantle, we suggest that magmatism of Type 1 occurred in the mantle sources at the asthenosphere–lithosphere boundary and the underlying asthenosphere as a reflection of a relatively weak mantle flow that may have ascended from a depth of ~250 km. Magmatism of Type 2 occurred in the isolated sources of the sublithospheric mantle and the asthenosphere–lithosphere boundary as an evidence on the initially strong mantle flow that may have ascended from a depth of ~410 km

THE MIOCENE AND DEVONIAN MAGMATISM AT THE JUNCTION BETWEEN THE TUVA-MONGOLIAN MASSIF AND SIBERIAN CRATON: COMMON COMPONENT OF MANTLE SOURCES AND ITS ORIGIN

Devonian dikes of the Urik-Belaya and Shagayte-Gol-Urik zones and Miocene lavas of the Urik volcanic field are spatially associated with each other at the structural junction between the Neoproterozoic Tuva-Mongolian massif and Siberian craton. The former dike belt is represented by basalts and basaltic andesites of tholeiitic series and the latter one by trachybasalts, trachyandesitic basalts of moderately alkaline series and trachybasalts, phonotephrites of highly alkaline one. The Urik volcanic field is composed of trachybasalts and trachyandesitic basalts of moderately alkaline series. A partial similarity between magmatic series of different age is found in terms of major oxides, trace elements, and Sr, Pb isotopes. The common component corrected for age was defined through its converging mixing trends with those of the lithospheric mantle and crust. The component identification was a basis for deciphering the nature of isotopic and geochemical heterogeneity of evolved magmatic sources. It was inferred that the common component characterizes either a modified (depleted) reservoir of the lower mantle or, more likely, a local region of the convecting asthenospheric mantle that underlies the Tuva-Mongolian massif. The latter interpretation assumes the formation of a locally convecting asthenosphere in the middle Neoproterozoic, along with the development of the Oka zone at the massif, and puts constrains on later sufficient processing of the asthenosphere due to rising plumes or subducting slabs

ACADEMICIAN N.A. LOGATCHEV AND HIS SCIENTIFIC SCHOOL: CONTRUBITION TO STUDIES OF THE CENOZOIC CONTINENTAL RIFTING

N.A. Florensov and N.A. Logatchev pioneered development of fundamental concepts of the structure and evolution of the Baikal system of rift basins. At the turn to the 21st century, in view of the wide availability of scientific research data on the Cenozoic continental rift zones located in Eurasia, Africa and North America, and taking into account the application of new research methods and options to process and analyze huge amounts of geological and geophysical data, a priority was comprehensive modeling of rifting from its origin to the current period of time. This scientific challenge was addressed by the research team under the leadership of N.A. Logachev