scholarly journals Evolutionary Trajectory of the Replication Mode of Bacterial Replicons

mBio ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Bin-Bin Xie ◽  
Jin-Cheng Rong ◽  
Bai-Lu Tang ◽  
Sishuo Wang ◽  
Guiming Liu ◽  
...  
Keyword(s):  
Chromosome Replication ◽  
Comparative Genomic ◽  
Evolutionary Trajectory ◽  
Exogenous Dna ◽  
Bacterial Phyla ◽  
Metabolic Versatility ◽  
Bacterial Chromosomes ◽  
History Of ◽  
Replication Terminus ◽  
Two Stages

ABSTRACT As typical bacterial replicons, circular chromosomes replicate bidirectionally and circular plasmids replicate either bidirectionally or unidirectionally. Whereas the finding of chromids (plasmid-derived chromosomes) in multiple bacterial lineages provides circumstantial evidence that chromosomes likely evolved from plasmids, all experimentally assayed chromids were shown to use bidirectional replication. Here, we employed a model system, the marine bacterial genus Pseudoalteromonas, members of which consistently carry a chromosome and a chromid. We provide experimental and bioinformatic evidence that while chromids in a few strains replicate bidirectionally, most replicate unidirectionally. This is the first experimental demonstration of the unidirectional replication mode in bacterial chromids. Phylogenomic and comparative genomic analyses showed that the bidirectional replication evolved only once from a unidirectional ancestor and that this transition was associated with insertions of exogenous DNA and relocation of the replication terminus region (ter2) from near the origin site (ori2) to a position roughly opposite it. This process enables a plasmid-derived chromosome to increase its size and expand the bacterium’s metabolic versatility while keeping its replication synchronized with that of the main chromosome. A major implication of our study is that the uni- and bidirectionally replicating chromids may represent two stages on the evolutionary trajectory from unidirectionally replicating plasmids to bidirectionally replicating chromosomes in bacteria. Further bioinformatic analyses predicted unidirectionally replicating chromids in several unrelated bacterial phyla, suggesting that evolution from unidirectionally to bidirectionally replicating replicons occurred multiple times in bacteria. IMPORTANCE Chromosome replication is an essential process for cell division. The mode of chromosome replication has important impacts on the structure of the chromosome and replication speed. Bidirectional replication is the rule for bacterial chromosomes, and unidirectional replication has been found only in plasmids. To date, no bacterial chromosomes have been experimentally demonstrated to replicate unidirectionally. Here, we showed that the chromids (plasmid-derived chromosomes) in Pseudoalteromonas replicate either uni- or bidirectionally and that a single evolutionary transition from uni- to bidirectionality explains this diversity. These uni- and bidirectionally replicating chromids likely represent two stages during the evolution from a small and unidirectionally replicating plasmid to a large and bidirectionally replicating chromosome. This study provides insights into both the physiology of chromosome replication and the early evolutionary history of bacterial chromosomes.

Plastic deformations in kyanites by tectonometamorphic processes: a single-crystal X-ray diffraction study

2009 ◽  
Vol 73 (3) ◽  
pp. 359-371 ◽  
Author(s):  
G. D. Gatta ◽  
N. Rotiroti ◽  
M. Zucali
Keyword(s):  
Single Crystal ◽  
X Ray Diffraction ◽  
Plastic Deformations ◽  
X Ray ◽  
Deformational History ◽  
Significant Difference ◽  
Elliptical Section ◽  
History Of ◽  
Diffraction Patterns ◽  
Two Stages

AbstractThe crystalch emistry and crystal structure of naturalky anite crystals from the Eclogitic Micaschists Complex of the Sesia-Lanzo Zone, Western Italian Alps, have been investigated by means of optical microscopy, wavelength dispersive X-ray microanalysis, and single-crystal X-ray diffraction. The association of kyanite + garnet + phengitic-mica + chloritoid suggests that the eclogite-facies stages occurred at P ≤ 2.1 GPa and T ≤ 650ºC. Kyanite grains are large (cm-sized) porphyroblasts grown dynamically during one of the deformational events related to the subduction of the Austroalpine continentalcr ust. Under the polarizing microscope, kyanite grains show almost homogeneous cores, whereas rims are sometimes symplectitic aggregates of quartz and kyanite, confirming at least two stages of growth most likely related to the multistage deformational history of these rocks. Chemical analysis shows that Fe3+ is the major substituting cation for Al3+, ranging between 0.038 and 0.067 a.p.f.u.The single-crystal X-ray diffraction investigation of the kyanites shows severely textured patterns on the (h0l)*-plane. Such evidence is not observed in the unwarped diffraction patterns on (0kl)* and (hk0)*. The most significant difference between the structuralp arameters refined in this study, with respect to those of previously published unstrained gem-quality crystals, concerns the displacement parameters. The anisotropic displacement ellipsoids of all the atomic sites are significantly larger than those previously described, and systematically oriented with the largest elliptical section almost perpendicular to [010]. The larger ellipsoids in the kyanite crystal investigated here reflect the displacement of the centre of gravity of the electron distribution, rather than an anomalous atomic thermal motion. The magnitude and orientation of the displacement parameters and the textured/strained diffraction pattern may be the result of two combined effects: (1) that the kyanite crystals are actually composed of several blocks; (2) the crystals are affected by a pervasive residual strain, as a result of tectonometamorphic plastic deformations and re-crystallization.

scholarly journals HISTORY OF DEVELOPING THE CONCEPT OF «LARGE SOCIAL GROUPS». PART 1: PERIOD FROM THE MID-19th CENTURY TO THE MID-1930-Х YEARS OF SOCIAL PSYCHOLOGY DEVELOPMENT

2020 ◽  
pp. 390-418
Author(s):  
Ю.В. Ковалева
Keyword(s):  
Social Psychology ◽  
Social Life ◽  
Social Groups ◽  
Social Situation ◽  
Social Phenomena ◽  
Psychological Study ◽  
The Social ◽  
History Of ◽  
The One ◽  
Two Stages

Представлен историографический анализ развития понятия большие социальные группы и историко-психологический анализ социальных феноменов , связанных с массовыми общественными явлениями в России. Сформулированы актуальные проблемы психологии больших социальных групп, к которым относятся неоднородность оснований для их выделения, недостаточная дифференцированность со сходными понятиями, неравномерность исследований в различные временные периоды и идеологическая нагруженность их разработки. Данная работа была ответом на необходимость восполнения знаний о процессах в таких группах, происходивших в различные исторические периоды развития социальной психологии, с соответствующим им уровнем научного осмысления, а также обобщением этой целостной картины на уровне современного понимания и формулировка перспективных направлений исследований. Целью исследования является установление связи между определением и основными свойствами понятия «большие социальные группы» (его синонимов, аналогов) и особенностями социальной ситуации в определенный период времени, а также реконструкция социальных процессов данного исторического этапа. Проверялась гипотеза о том, что большие социальные группы как феномены социальной жизни формировались в соответствии с историческим временем, а соответствующее им понятие и его свойства с одной стороны отвечали уровню развития гуманитарного знания, а с другой - пытались удовлетворить общественный и политический запрос в объяснении и управлении социальной ситуацией. Использовались методы историографии социальной психологии и психолого-исторической реконструкции . Первая часть статьи посвящена анализу первых двух этапов развития социальной психологии - с середины XIX до начала XX вв. и в 1920-е гг. XX в. The historiographic analysis of the development of the concept of large social groups and historical and psychological study of social phenomena associated with mass social phenomena was presented. Topical problems of the psychology of large social groups are formulated, including heterogeneity of the grounds for their isolation, insufficient differentiation with similar concepts, uneven research in various periods, and ideological loading of the history of its development. The study's main problem was the need to replenish the processes in such groups that took place in various historical periods of social psychology development as well as a synthesis of this holistic picture at the level of modern understanding and the formulation of promising areas of research. The study's purpose was to establish a connection between the definition and the basic properties of the concept of "large social groups" (and its synonyms, analogs) and the peculiarities of the social situation in a certain period, as well as the reconstruction of social processes of this historical segment. The hypothesis was tested that large social groups as phenomena of social life were formed under the past time. The concept and its properties were corresponding to them, on the one hand, compared to the level of development of humanitarian knowledge. On the other, they tried to satisfy the social and political requests to understand and manage the social situation. Methods of the historiography of the history of social psychology and psychological and historical reconstruction were used. The article's first part was devoted to the analysis of the early two stages of the development of social psychology - from the middle of the XIX to the beginning of the XX centuries and 1920 of the XX century.

scholarly journals Erichthonius or Theseus, who established the Panathenaea?

2021 ◽  
Vol 13 (3) ◽  
pp. 259-268
Author(s):  
Tatiana Borisovna Gvozdeva
Keyword(s):  
Olympic Games ◽  
Urban Community ◽  
Vase Painting ◽  
New Name ◽  
New Information ◽  
History Of ◽  
Two Stages ◽  
Regional Character ◽  
The Olympic Games

The sources know two versions of the establishing of Panathenaia, the main public holiday of the Athenian polis. The earliest version of aition of Panathenaia is associated with the history of the Athenian indigenous king Erichthonius. The son of Gaia and Hephaestus, Erichthonius was raised by the goddess Athena on the Acropolis, and after becoming king of Athens, he dedicated the feast of Panathenaia to the goddess. In the source, he is the first founder of the holiday. However, two types of Panathenaia were known in Athens: the Lesser Panathenaia, which were held annually, and the Greater Panathenaia, which, like the Olympic Games, were held every four years. Gradually, there appear pieces of new information about the history of the establishing of the Panathenaia in the mythological tradition. Now the authors distinguish two stages in the history of the feast, wherein the earlier one was called Athenaia. Gradually Erichthonius was relegated to the background, as founder Athenaeus, whereas the holiday got a new name - Panathenaia. This process was often associated with the synoekismus of Theseus, when he had united all the Athenians into one urban community. The cult of Theseus became especially popular in Athens after the reforms of Cleisthenes. Theseus' exploits are becoming a popular theme in Attic vase painting, especially scenes depicting the struggle, which Theseus was believed to be the founder of in Athens. At the same time, the program of the Panathenaic Games was expanding, the Panathenaia gradually acquired a supra-regional character.

scholarly journals Comprehensive Rehabilitation After Reconstruction of the Anterior Cruciate Ligament

2021 ◽  
Vol 11 (8) ◽  
pp. 182-193
Author(s):  
Dawid Besztak ◽  
Karina Szczypiór-Piasecka ◽  
Alicja Mińko ◽  
Krzysztof Antczak
Keyword(s):  
Anterior Cruciate Ligament ◽  
Knee Joint ◽  
Cruciate Ligament ◽  
Treatment Options ◽  
Rehabilitation Process ◽  
History Of ◽  
Comprehensive Rehabilitation ◽  
Anterior Cruciate ◽  
Two Stages ◽  
Hospital Rehabilitation

Introduction: The knee joint is the second most frequently injured joint. Anterior cruciate ligament (ACL) injury is a relatively common injury to the inner part of the knee joint, mainly related to contact sports. Its rupture leads to instability of the entire joint. Two treatment options are possible: operative or conservative. Each of them is related to an appropriate rehabilitation process. The aim of this study was to define a comprehensive rehabilitation plan in patients after ACL rupture and meniscal suturing.Materials and methods: The work was written based on the medical history of the patient who was diagnosed with complete rupture of ACL, and then reconstruction was performed with the harvesting of a semitendinous and slender muscle graft.Results: The rehabilitation process can be divided into two stages: hospital and post-hospital. Rehabilitation in hospital conditions begins on the zero day after arthroscopy. The main goals of rehabilitation include: increasing the range of mobility, no myofascial dysfunctions, no thromboembolic complications, and the ability to self-service.Conclusion: Rehabilitation is an indispensable element of the treatment of patients after ACL reconstruction. Early initiation of rehabilitation brings tangible benefits during treatment and return to full physical fitness.

«(Великая) культурная революция» в приграничных к СССР районах КНР: ХулунБуир, провинция Хэйлунцзян (1966–1976 гг.)

2020 ◽  
pp. 127-134
Author(s):  
Ochirov Ts. Solbonovich ◽  
Keyword(s):  
Cultural Revolution ◽  
Industrial Development ◽  
Political Campaigns ◽  
Contemporary History ◽  
Initial Stage ◽  
History Of ◽  
Oriental Studies ◽  
Two Stages ◽  
The Given ◽  
The Cultural Revolution

The research of the problems of the contemporary history of the NorthEastern China including the analysis of ideological and political campaigns of the second half of the XX century is one of the high-potential fields of the Oriental studies in our country. The article focuses on the period of the (Great) ‘Cultural Revolution’ (1966–1976) at bordering USSR Chinese regions — Heilongjiang province and Khulun-Buir aimak of the autonomous region of Inner Mongolia. The goals of the study are set in concurrence with chronological order of the events: the ‘cultural revolution’ in the above mentioned regions had two stages. The study is based on the works of the Chinese historians. The given research highlights the specific features of the initial stage of the “cultural revolution” including the criticism of the party officials, establishment of revolution committees and running a political campaign ‘vasu’; considers the Soviet-Chinese conflict at the Daman island in 1969 to be a factor in the following political stabilization of the bordering territories; examines the movement for restoration of the party apparatus and the boost in the industrial development in 1970s of the last century.

A Bibliography of Soviet Studies of the Ancient Cultures of Latin America

1990 ◽  
Vol 1 (1) ◽  
pp. 5-22
Author(s):  
V. A. Bashilov ◽  
V. I. Gulyaev
Keyword(s):  
Latin America ◽  
Latin American ◽  
Latin American Studies ◽  
Historical Processes ◽  
Third Stage ◽  
Archaeological Materials ◽  
Art And Culture ◽  
History Of ◽  
Two Stages ◽  
Second Period

The study in the Union of Soviet Socialist Republics of the earliest history of native Latin Americans falls into two distinct periods. The first, associated with an interest in the ancient Mexican and Peruvian civilizations, can be divided into two stages: the 1920s to the early 1940s, when Soviet scholars first acquainted themselves with antiquities from the region and used them for historical parallels; and the late 1940s and early 1950s, when Soviet historians turned to an analysis of Latin American materials. The second period went through three stages: the first, from the early 1950s to the early 1960s, mainly was dominated by Yury Knorozov, who was engaged in deciphering the language of the Maya, and Rostislav Kinzhalov, who studied their art and culture. During the second stage, the early 1960s to the mid-1970s, more scholars and research institutions undertook studies of the early cultures of Latin America. The thematic range became wider as well, covering—besides Mesoamerica and the central Andean region—the Intermediate region and the Caribbean. The third stage, which started in the late 1970s and continues to the present day, witnesses ethnographers and archaeologists pooling their efforts in studying the region. There were several conferences in which specialists engaged in various fields of Latin American studies participated. Their contacts with foreign colleagues became wider; Soviet archaeologists and ethnologists took part in fieldwork in Latin America. The primary aims today are to introduce Soviet readers to archaeological materials from a number of cultural-historical regions (such as the southern fringes of Mesoamerica, Amazonia, the southern Andes, etc.), to detail Soviet studies of cultural complexes and historical processes in ancient America, and to compare them to the processes that took place in the Old World, with the aim of establishing shared historical “laws” and patterns.

HYDROCARBON-RELATED DIAGENETIC ZONES (HRDZs) IN THE VULCAN SUB-BASIN, TIMOR SEA: RECOGNITION AND EXPLORATION IMPLICATIONS

1995 ◽  
Vol 35 (1) ◽  
pp. 220 ◽  
Author(s):  
G.W. O'Brien ◽  
E.P. Woods
Keyword(s):  
Late Miocene ◽  
Predictive Tool ◽  
Hydrocarbon Migration ◽  
Areal Distribution ◽  
Carbon Isotopic ◽  
Individual Structure ◽  
History Of ◽  
Timor Sea ◽  
Two Stages ◽  
Migration Pathways

Within very localised areas of the Vulcan Subbasin, the Eocene Grebe Formation sandstones are strongly cemented with carbonate. These cemented sands are recognisable on seismic data as zones of anomalously high velocity, and result in both time 'pull-up' and deterioration of the stack response in the underlying section.To determine the nature and origin of these cemented zones, their isotopic, mineralogical and petrologic compositions have been characterised, their seismic response and areal distribution established, and these observations integrated with ~2,730 km of AGSO water column geochemical ('sniffer-type') data.The carbon isotopic compositions of the carbonate within the cemented Grebe sands are diagnostic of carbonates formed principally via the oxidation of migrating, thermogenic hydrocarbons. Oxidation of the hydrocarbons took place in two stages: an earlier phase led to calcite precipitation, whereas a later phase produced (generally subsidiary) ferroan dolomite/ankerite cementation.Areas of known, present-day hydrocarbon seepage from the seafloor, such as over major faults on the Skua Horst and along the Vulcan Sub-basin/ Londonderry High boundary zone, are invariably associated with zones of highly cemented Eocene sands. Similarly, areas of known Tertiary hydrocarbon seepage, such as those associated with the residual oil columns on the Eider Horst, also contain strongly cemented Eocene sandstones.These observations have established a causal relationship between the presence of these Hydrocarbon-Related Diagenetic Zones (or HRDZs) in the Eocene sandstones and Tertiary-Quaternary hydrocarbon seepage. It is likely that most of the cementation occurred during the Late Miocene/Early Pliocene, when the Grebe Formation sands were at a shallow depth of burial(Recognition of this causal association has allowed several insights to be gained into the exploration potential and reactivation history of structures within the Vulcan Sub-basin. Mapping of the areal distribution of the cemented zones can effectively define hydrocarbon migration pathways. More importantly, however, predictable relationships exist between the seismic expression of the HRDZs, the total amount of hydrocarbons that have leaked from the traps, and the obliquity between the Jurassic and Late Miocene fault trends over the respective structures. A continuum exists between highintegrity accumulations, in which the fault trends are parallel and the HRDZs are small or absent, and breached accumulations, in which a significant obliquity exists between the respective fault trends and the HRDZs are large and seismically-intense.These observations provide a potential predictive tool for evaluating undrilled structures. It may be possible to determine, from the integration of seismic structural mapping and the characterisation of the seismic expression of the HRDZs, not only whether an individual structure is ever likely to have had a hydrocarbon column, but whether that column is likely to be preserved.

scholarly journals Whole Genome Sequencing and Comparative Genomic Analyses of Lysinibacillus pakistanensis LZH-9, a Halotolerant Strain with Excellent COD Removal Capability

2020 ◽  
Vol 8 (5) ◽  
pp. 716
Author(s):  
Xueling Wu ◽  
Han Zhou ◽  
Liangzhi Li ◽  
Enhui Wang ◽  
Xiangyu Zhou ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Industrial Wastewater ◽  
Treatment Plant ◽  
Cod Removal ◽  
Comparative Genomic ◽  
Whole Genome ◽  
Toxic Compound ◽  
Adaptive Mutations ◽  
Metabolic Versatility

Halotolerant microorganisms are promising in bio-treatment of hypersaline industrial wastewater. Four halotolerant bacteria strains were isolated from wastewater treatment plant, of which a strain LZH-9 could grow in the presence of up to 14% (w/v) NaCl, and it removed 81.9% chemical oxygen demand (COD) at 96 h after optimization. Whole genome sequencing of Lysinibacillus pakistanensis LZH-9 and comparative genomic analysis revealed metabolic versatility of different species of Lysinibacillus, and abundant genes involved in xenobiotics biodegradation, resistance to toxic compound, and salinity were found in all tested species of Lysinibacillus, in which Horizontal Gene Transfer (HGT) contributed to the acquisition of many important properties of Lysinibacillus spp. such as toxic compound resistance and osmotic stress resistance as revealed by phylogenetic analyses. Besides, genome wide positive selection analyses revealed seven genes that contained adaptive mutations in Lysinibacillus spp., most of which were multifunctional. Further expression assessment with Codon Adaption Index (CAI) also reflected the high metabolic rate of L. pakistanensis to digest potential carbon or nitrogen sources in organic contaminants, which was closely linked with efficient COD removal ability of strain LZH-9. The high COD removal efficiency and halotolerance as well as genomic evidences suggested that L. pakistanensis LZH-9 was promising in treating hypersaline industrial wastewater.

Past hot fluid flows in limestones detected by Δ47–(U-Pb) and not recorded by other geothermometers

Geology ◽  
2020 ◽  
Vol 48 (9) ◽  
pp. 851-856 ◽  
Author(s):  
Benjamin Brigaud ◽  
Magali Bonifacie ◽  
Maurice Pagel ◽  
Thomas Blaise ◽  
Damien Calmels ◽  
...  
Keyword(s):  
Fluid Inclusions ◽  
Thermal History ◽  
Vitrinite Reflectance ◽  
Fluid Flows ◽  
Aqueous Fluid ◽  
Rift System ◽  
History Of ◽  
Clumped Isotope ◽  
Two Stages ◽  
Rock Eval

Abstract Geothermometers are commonly used to reconstruct the diagenetic and thermal history of rocks. However, characterizing the timing, origin, and temperature of paleofluid flow remains challenging because it must be assessed indirectly through the analysis of microscopic cements that precipitate and fill intergranular spaces during fluid circulation. Here, we measure both the clumped isotope (Δ47) temperature and in situ U-Pb age of individual diagenetic calcite cements within a sedimentary section of the Paris Basin (France), whose thermal history has been previously inferred to be <60 °C. We show that cementation occurred during two stages associated with major events at the western European lithospheric scale: (1) the Bay of Biscay rifting (Late Jurassic–Early Cretaceous), and (2) north-south Pyrenean compression (Eocene) followed by east-west extension during the European Cenozoic rift system event (Oligocene). Related to both events, we report unexpectedly hot fluids, up to 110 °C, contrasting with the lower temperatures inferred from other geothermometers (e.g., fluid inclusions, clay minerals, apatite fission tracks, maturity of organic matter by Rock-Eval pyrolysis, or vitrinite reflectance). These high temperatures (>70 °C) have been measured for calcite cements containing single-phase aqueous fluid inclusions, challenging the commonly accepted assertion that the absence of nucleation of a vapor phase indicates crystallization at low temperature (∼<70 °C). We suggest that the kinetics of mineralization events prevented the recording of short-lived hot fluid flows by other geothermometers.

Sign in / Sign up

Export Citation Format

Share Document