scholarly journals Viral Long-Term Evolutionary Strategies Favor Stability over Proliferation

Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 677 ◽  
Author(s):  
Stéphane Aris-Brosou ◽  
Louis Parent ◽  
Neke Ibeh
Keyword(s):  
Viral Evolution ◽  
Amino Acid Level ◽  
Evolutionary Strategies ◽  
Mutation Rates ◽  
Correlated Evolution ◽  
Dna Viruses ◽  
Show Evidence ◽  
Evolutionary Trajectories ◽  
Key Aspects

Viruses are known to have some of the highest and most diverse mutation rates found in any biological replicator, with single-stranded (ss) RNA viruses evolving the fastest, and double-stranded (ds) DNA viruses having rates approaching those of bacteria. As mutation rates are tightly and negatively correlated with genome size, selection is a clear driver of viral evolution. However, the role of intragenomic interactions as drivers of viral evolution is still unclear. To understand how these two processes affect the long-term evolution of viruses infecting humans, we comprehensively analyzed ssRNA, ssDNA, dsRNA, and dsDNA viruses, to find which virus types and which functions show evidence for episodic diversifying selection and correlated evolution. We show that selection mostly affects single stranded viruses, that correlated evolution is more prevalent in DNA viruses, and that both processes, taken independently, mostly affect viral replication. However, the genes that are jointly affected by both processes are involved in key aspects of their life cycle, favoring viral stability over proliferation. We further show that both evolutionary processes are intimately linked at the amino acid level, which suggests that it is the joint action of selection and correlated evolution, and not just selection, that shapes the evolutionary trajectories of viruses—and possibly of their epidemiological potential.

scholarly journals Episodic diversifying selection and intragenomic interactions shape the evolution of DNA and RNA viruses

2019 ◽  
Author(s):  
Stéphane Aris-Brosou ◽  
Louis Parent ◽  
Neke Ibeh
Keyword(s):  
Rna Viruses ◽  
Viral Evolution ◽  
Amino Acid Level ◽  
Mutation Rates ◽  
Correlated Evolution ◽  
Dna Viruses ◽  
Diversifying Selection ◽  
Dna And Rna ◽  
Show Evidence ◽  
Key Aspects

AbstractViruses are known to have some of the highest and most diverse mutation rates found in any biological replicator, topped by single-stranded (ss) RNA viruses, while double-stranded (ds) DNA viruses have rates approaching those of bacteria. As mutation rates are tightly and negatively correlated with genome size, selection is a clear driver of viral evolution. However, the role of intragenomic interactions as drivers of viral evolution is less well documented. To understand how these two processes affect viral evolution, we systematically surveyed ssRNA, ssDNA, dsRNA, and dsDNA viruses, to find which virus type and which functions show evidence for episodic diversifying selection and correlated evolution. We show that while evidence for selection is mostly found in single stranded viruses, and correlated evolution is more prevalent in DNA viruses, the genes that are affected by both processes are involved in key aspects of their life cycle, favoring viral stability over proliferation. We further show that both evolutionary processes are intimately linked at the amino acid level, which suggests that selection alone does not explain the whole evolutionary —and epidemiological— potential of viruses.

Evolutionary Approaches to Innovation, the Firm, and the Dynamics of Industries

2021 ◽  
Vol 6 (4) ◽  
pp. 265-289
Author(s):  
Gino Cattani ◽  
Franco Malerba
Keyword(s):  
Dynamic Capabilities ◽  
Evolutionary Strategies ◽  
Industry Dynamics ◽  
The Road ◽  
Evolutionary Trajectories ◽  
Quantitative Analyses ◽  
Important Progress ◽  
Made In

We examine the progress of the evolutionary research on innovation, the firm, and the dynamics of industries in the last four decades. The paper acknowledges that the themes related to knowledge and technological regimes, the evolutionary processes leading to innovation, and the long-term dynamics of technologies have generated, and still remain, relevant research trajectories. The same can be said for the research trajectories on organizational and dynamic capabilities, evolutionary strategies, vertical integration, diversification, niche construction, and authority and power in organizations. Important progress has also been made in understanding the evolutionary trajectories of industries, the link between industry architecture and industry dynamics, the types of knowledge of entrants, the role of focal and vertical spinouts, the relevance of institutions and sectoral innovation systems in industry dynamics, and the catch-up process by firms from latecomer countries. We argue that future developments in the evolutionary camp should continue to be characterized by eclecticism and multidisciplinarity, as well as by the integration of different methodologies from cases to stylized facts, quantitative analyses, appreciative theorizing, and formal modelling. We conclude with an analysis of the main methodologies used by evolutionary scholars and a discussion of the road ahead.

The Stability of the WHO Reference Thromboplastin NIBS & C 67/40

1979 ◽  
Vol 42 (04) ◽  
pp. 1135-1140 ◽  
Author(s):  
G I C Ingram
Keyword(s):  
Human Brain ◽  
Collaborative Study ◽  
Calibration Constant ◽  
Long Term Stability ◽  
Freeze Dried ◽  
Show Evidence ◽  
Human Material ◽  
Reference Preparation ◽  
The Stability

SummaryThe International Reference Preparation of human brain thromboplastin coded 67/40 has been thought to show evidence of instability. The evidence is discussed and is not thought to be strong; but it is suggested that it would be wise to replace 67/40 with a new preparation of human brain, both for this reason and because 67/40 is in a form (like Thrombotest) in which few workers seem to use human brain. A �plain� preparation would be more appropriate; and a freeze-dried sample of BCT is recommended as the successor preparation. The opportunity should be taken also to replace the corresponding ox and rabbit preparations. In the collaborative study which would be required it would then be desirable to test in parallel the three old and the three new preparations. The relative sensitivities of the old preparations could be compared with those found in earlier studies to obtain further evidence on the stability of 67/40; if stability were confirmed, the new preparations should be calibrated against it, but if not, the new human material should receive a calibration constant of 1.0 and the new ox and rabbit materials calibrated against that.The types of evidence available for monitoring the long-term stability of a thromboplastin are discussed.

scholarly journals Inhibitory interneurons of the human prefrontal cortex display conserved evolution of the phenotype and related genes

2009 ◽  
Vol 277 (1684) ◽  
pp. 1011-1020 ◽  
Author(s):  
Chet C. Sherwood ◽  
Mary Ann Raghanti ◽  
Cheryl D. Stimpson ◽  
Muhammad A. Spocter ◽  
Monica Uddin ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Calcium Binding ◽  
Amino Acid Level ◽  
Primate Evolution ◽  
Inhibitory Interneurons ◽  
Cognitive Domains ◽  
Inhibitory Circuitry ◽  
Show Evidence ◽  
Anthropoid Primates ◽  
And Migration

Inhibitory interneurons participate in local processing circuits, playing a central role in executive cognitive functions of the prefrontal cortex. Although humans differ from other primates in a number of cognitive domains, it is not currently known whether the interneuron system has changed in the course of primate evolution leading to our species. In this study, we examined the distribution of different interneuron subtypes in the prefrontal cortex of anthropoid primates as revealed by immunohistochemistry against the calcium-binding proteins calbindin, calretinin and parvalbumin. In addition, we tested whether genes involved in the specification, differentiation and migration of interneurons show evidence of positive selection in the evolution of humans. Our findings demonstrate that cellular distributions of interneuron subtypes in human prefrontal cortex are similar to other anthropoid primates and can be explained by general scaling rules. Furthermore, genes underlying interneuron development are highly conserved at the amino acid level in primate evolution. Taken together, these results suggest that the prefrontal cortex in humans retains a similar inhibitory circuitry to that in closely related primates, even though it performs functional operations that are unique to our species. Thus, it is likely that other significant modifications to the connectivity and molecular biology of the prefrontal cortex were overlaid on this conserved interneuron architecture in the course of human evolution.

scholarly journals CD34+ human marrow cells that express low levels of Kit protein are enriched for long-term marrow-engrafting cells

Blood ◽  
1996 ◽  
Vol 87 (10) ◽  
pp. 4136-4142 ◽  
Author(s):  
I Kawashima ◽  
ED Zanjani ◽  
G Almaida-Porada ◽  
AW Flake ◽  
H Zeng ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Marrow Cell ◽  
In Utero ◽  
Fetal Sheep ◽  
Hematopoietic Stem ◽  
Show Evidence ◽  
Marrow Cells

Using in utero transplantation into fetal sheep, we examined the capability of human bone marrow CD34+ cells fractionated based on Kit protein expression to provide long-term in vivo engraftment. Twelve hundred to 5,000 CD34+ Kit-, CD34+ Kit(low), and CD34+ Kit(high) cells were injected into a total of 14 preimmune fetal sheep recipients using the amniotic bubble technique. Six fetuses were killed in utero 1.5 months after bone marrow cell transplantation. Two fetuses receiving CD34+ Kit(low) cells showed signs of engraftment according to analysis of CD45+ cells in their bone marrow cells and karyotype studies of the colonies grown in methylcellulose culture. In contrast, two fetuses receiving CD34+ Kit(high) cells and two fetuses receiving CD34+ Kit- cells failed to show evidence of significant engraftment. Two fetuses were absorbed. A total of six fetuses receiving different cell populations were allowed to proceed to term, and the newborn sheep were serially examined for the presence of chimerism. Again, only the two sheep receiving CD34+ Kit(low) cells exhibited signs of engraftment upon serial examination. Earlier in studies of murine hematopoiesis, we have shown stage-specific changes in Kit expression by the progenitors. The studies of human cells reported here are in agreement with observations in mice, and indicate that human hematopoietic stem cells are enriched in the Kit(low) population.

The use of artificial neural networks in the problem of classifying cloud types in wide-angle images of the visible hemisphere of the sky.

2021 ◽  
Author(s):  
Nikita Veremev
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Cloud Cover ◽  
Human Factor ◽  
Wide Angle ◽  
Reliable Determination ◽  
Air Masses ◽  
Key Aspects

<p>Within the framework of meteorology and oceanology, the importance of the cloud mass and the type of clouds cannot be underestimated. When describing and studying weather, precipitation and the movement of air masses over the ocean, the amount and type of clouds determines the flows of precipitation, their intensity, helps to predict the weather and the content of various impurities in the air, which makes the study of the properties of cloud cover one of the key aspects of meteorological and oceanological research.</p><p>The types of clouds are determined by the specialist, visually comparing the picture of the sky over the ocean with the guideline documents, the use of which reduces the possibility of the human factor affecting the determination of these parameters.</p><p>For an accurate study, study of the dynamics and dependence of climatic models on the conditions of cloud types, long-term measurements of the same type and the continuity of their methods are required. However, all these data are very unevenly distributed over the Earth's surface, and the number of ship observations is greatly reduced.</p><p>Thus, taking into account the importance of reliable determination of data related to cloudiness and the problems of their accuracy, the relevance and need to automate the determination of cloud types are obvious.</p><p>As a result of the work, an algorithm was obtained that allows classifying cloud types based on photographs taken during long-term sea expeditions.</p>

Crossing cultural borders: A case study of conceptual design outcomes of U.S. and Moroccan student samples

2021 ◽  
pp. 1-42
Author(s):  
Aoran Peng ◽  
Jessica Menold ◽  
Scarlett Miller
Keyword(s):  
Global Economy ◽  
Design Theory ◽  
Design Thinking ◽  
Emerging Market ◽  
Gender Effects ◽  
Concept Generation ◽  
Design Theory And Methodology ◽  
Key Aspects ◽  
The U.S

Abstract There has been a plethora of design theory and methodology research conducted to answer important questions centered around how ideas are developed and translated into successful products. Understanding this is vital because of the role creativity and innovation have in long-term economic success. However, most of this research have focused on U.S. samples, leaving to question if differences exist across cultural borders. Answering this question is key to supporting a successful global economy. The current work provides a first step at answering this question by examining similarities and differences in concept generation and screening practices between students in an emerging market, Morocco, and those in a more established market, the U.S during a design thinking workshop. Our results show that while students in the U.S. sample produced more ideas than the Moroccan sample, there was no difference in the perceived quality of ideas generated (idea goodness). In addition, while U.S. women were found to produce more ideas than U.S. men, there were no gender effects for students in the Moroccan sample. Finally, the results show that ideas with low goodness had a higher probability of passing concept screening if it was evaluated by its owner regardless of the population studied – identifying the potential impact of ownership bias across cultures. As a whole, these results suggest that key aspects of design theory and methodology research may in fact translate across cultures but also identified key areas for further investigation.

KEY ASPECTS OF THE CREDIT AND LOAN ACCOUNTING PROCESS

2021 ◽  
Vol 4 (4) ◽  
pp. 175-181
Author(s):  
S. N. KOVALENKO ◽  
◽  
Yu. N. KOVALENKO ◽  
Keyword(s):  
Financial Statements ◽  
Short Term ◽  
Economic Entity ◽  
Analytical Review ◽  
Key Aspects

The article presents the procedure for accounting for borrowed funds, short-term and long-term, provides an analytical review of the accounting financial statements, regarding loans and borrowings of an economic entity.

scholarly journals Patient-individual cancer cell lines and tissue analysis delivers no evidence for a role of DNA virus infection on colorectal cancer oncogenesis

2019 ◽  
Author(s):  
Michael Gock ◽  
Marcel Kordt ◽  
Stephanie Matschos ◽  
Christina S. Mullins ◽  
Michael Linnebacher
Keyword(s):  
Cell Lines ◽  
Molecular Subtypes ◽  
Morphological Changes ◽  
Tissue Analysis ◽  
Oncogenic Viruses ◽  
Dna Viruses ◽  
Viral Particles ◽  
Specific Sequences

Abstract Background Several DNA viruses are highly suspicious to have oncogenic effects in humans. This study investigates the presence of potentially oncogenic viruses such as SV40, JCV, BKV and EBV in patient-derived colorectal carcinoma (CRC) cells typifying all molecular subtypes of CRC. Methods Sample material (gDNA and cDNA) of a total of 49 patient-individual CRC cell lines and corresponding primary material from 11 patients, including normal, tumor-derived and metastasis-derived tissue were analyzed for sequences of SV40, JVC, BKV and EBV using endpoint PCR. In addition, the susceptibility of CRC cells to JCV and BKV was examined using a long-term cultivation approach of patient-individual cells in the presence of viruses. Results No virus-specific sequences could be detected in all specimens. Likewise, no morphological changes were observed and no evidence for viral infection or integration could be provided after long term CRC cell cultivation in presence of viral particles. Conclusions In summary, the presented data suggest that there is no direct correlation between tumorigenesis and viral load and consequently no evidence for a functional role of the DNA viruses included into this analysis in CRC development.

scholarly journals Short term but highly efficient Cas9 expression mediated by excisional system using adenovirus vector and Cre

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sayaka Nagamoto ◽  
Miyuki Agawa ◽  
Emi Tsuchitani ◽  
Kazunori Akimoto ◽  
Saki Kondo Matsushima ◽  
...  
Keyword(s):  
Hepatitis B ◽  
Genome Editing ◽  
Adenovirus Vector ◽  
Virus Genome ◽  
Dna Viruses ◽  
Tissue Specific ◽  
B Virus ◽  
Tissue Specific Promoter ◽  
A Cell

AbstractGenome editing techniques such as CRISPR/Cas9 have both become common gene engineering technologies and have been applied to gene therapy. However, the problems of increasing the efficiency of genome editing and reducing off-target effects that induce double-stranded breaks at unexpected sites in the genome remain. In this study, we developed a novel Cas9 transduction system, Exci-Cas9, using an adenovirus vector (AdV). Cas9 was expressed on a circular molecule excised by the site-specific recombinase Cre and succeeded in shortening the expression period compared to AdV, which expresses the gene of interest for at least 6 months. As an example, we chose hepatitis B, which currently has more than 200 million carriers in the world and frequently progresses to liver cirrhosis or hepatocellular carcinoma. The efficiencies of hepatitis B virus genome disruption by Exci-Cas9 and Cas9 expression by AdV directly (Avec) were the same, about 80–90%. Furthermore, Exci-Cas9 enabled cell- or tissue-specific genome editing by expressing Cre from a cell- or tissue-specific promoter. We believe that Exci-Cas9 developed in this study is useful not only for resolving the persistent expression of Cas9, which has been a problem in genome editing, but also for eliminating long-term DNA viruses such as human papilloma virus.

Sign in / Sign up

Export Citation Format

Share Document