scholarly journals Stepwise evolution of a butterfly supergene via duplication and inversion

2021 ◽  
Author(s):  
Kang-Wook Kim ◽  
Rishi De-Kayne ◽  
Ian J. Gordon ◽  
Kennedy Saitoti Omufwoko ◽  
Dino J. Martins ◽  
...  
Keyword(s):  
Structural Changes ◽  
Monarch Butterfly ◽  
Segmental Duplications ◽  
Recombination Suppression ◽  
Structural Differences ◽  
The Face ◽  
Suppressed Recombination ◽  
Stepwise Evolution ◽  
And Inversion

ABSTRACTSupergenes maintain adaptive clusters of alleles in the face of genetic mixing. Although usually attributed to inversions, there are few cases in which the specific mechanisms of recombination suppression, and their timing, have been reconstructed in detail. We investigated the origin of the BC supergene, which controls variation in warning colouration in the African Monarch butterfly, Danaus chrysippus. By generating chromosome-scale assemblies for all three alleles, we identified multiple structural differences. Most strikingly, we find that a region of >1 million bp underwent several segmental duplications at least 7.5 million years ago. The resulting duplicated fragments appear to have triggered four inversions in surrounding parts of the chromosome, resulting in stepwise growth of the region of suppressed recombination. Phylogenies for the inversions are incongruent with the species tree, and suggest that structural polymorphisms have persisted for at least 4.1 million years. In addition to the role of duplications in triggering inversions, our results suggest a previously undescribed mechanism of recombination suppression through independent losses of divergent duplicated tracts. Overall, our findings challenge the idea of instantaneous supergene evolution through a single inversion event, instead pointing towards a stepwise process involving a variety of structural changes.

scholarly journals Role of N501Y Mutation in SARS-CoV-2 Spike Protein Structure

2021 ◽  
Author(s):  
Urmi Roy
Keyword(s):  
Computer Simulation ◽  
Structural Changes ◽  
Spike Protein ◽  
Wild Type ◽  
Binding Domains ◽  
First Case ◽  
Mutant Variant ◽  
Structural Differences ◽  
Mutant Forms

It has been more than a year since the first case of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was found. This coronavirus has infected more than 110 million people worldwide by the end of February, 2021, and several virulent as well as more spreadable mutant forms of SARS-CoV-2 have emerged subsequently. In the latter group, three variants B.1.1.7, B.1.351, and P1 lineages, have been reported. Using computer simulation, the present paper investigates the structural differences between the wild type SARS-CoV-2 spike protein and its Asn501Tyr (N501Y) mutant variant. Time-based structural changes between the receptor binding domains of these two species are also examined. The N501Y mutation is common to all the three aforesaid mutant variants.

scholarly journals Co2+ Selectivity of Thermotoga maritima CorA and Its Inability to Regulate Mg2+ Homeostasis Present a New Class of CorA Proteins

2011 ◽  
Vol 286 (18) ◽  
pp. 16525-16532 ◽  
Author(s):  
Yu Xia ◽  
Anna-Karin Lundbäck ◽  
Newsha Sahaf ◽  
Gustav Nordlund ◽  
Peter Brzezinski ◽  
...  
Keyword(s):  
Structural Changes ◽  
Thermotoga Maritima ◽  
Main Role ◽  
Substrate Selection ◽  
New Class ◽  
Physiological Relevance ◽  
Structural Differences ◽  
High Concentrations

CorA is a family of divalent cation transporters ubiquitously present in bacteria and archaea. Although CorA can transport both Mg2+ and Co2+ almost equally well, its main role has been suggested to be that of primary Mg2+ transporter of prokaryotes and hence the regulator of Mg2+ homeostasis. The reason is that the affinity of CorA for Co2+ is relatively low and thus considered non-physiological. Here, we show that Thermotoga maritima CorA (TmCorA) is incapable of regulating the Mg2+ homeostasis and therefore cannot be the primary Mg2+ transporter of T. maritima. Further, our in vivo experiments confirm that TmCorA is a highly selective Co2+ transporter, as it selects Co2+ over Mg2+ at >100 times lower concentrations. In addition, we present data that show TmCorA to be extremely thermostable in the presence of Co2+. Mg2+ could not stabilize the protein to the same extent, even at high concentrations. We also show that addition of Co2+, but not Mg2+, specifically induces structural changes to the protein. Altogether, these data show that TmCorA has the role of being the transporter of Co2+ but not Mg2+. The physiological relevance and requirements of Co2+ in T. maritima is discussed and highlighted. We suggest that CorA may have different roles in different organisms. Such functional diversity is presumably a reflection of minor, but important structural differences within the CorA family that regulate the gating, substrate selection, and transport.

Public buildings and private opportunities: some dynamics in Pompeii’s urban development

2015 ◽  
Vol 28 ◽  
pp. 71-95
Author(s):  
Michael Anderson
Keyword(s):  
Urban Environment ◽  
Cultural Values ◽  
Structural Changes ◽  
Physical Reality ◽  
Small Scale ◽  
Urban Fabric ◽  
Archaeological Data ◽  
The Face ◽  
The Moment

Pompeii’s urban fabric presents a complicated palimpsest of construction, amalgamation, fission, renovation, and destruction, each being a reflection of the current social, economic and political realities at the moment the work was accomplished. Taken together, these data reveal how changing socio-cultural values gradually altered the face of the urban environment over time. However, while the overall transformation of the urban fabric is clearly a collective reflection of shifting concerns, it was really the actions of individuals that served to translate these trends into the physical reality that survives in the archaeological record. It was their particular decisions, undertaken in response to localised stimuli but expressing broad cultural trends and fashions, that served to produce, piece by piece, the complex and layered tapestry of the urban environment. Yet archaeological data only rarely provide the detail necessary to be able to identify the specific, small-scale motivations behind structural changes and the sequence of development, much less the ability to assess the positive or negative outcomes of particular decisions. Cases where it is possible to do so provide a rare window onto the localised, small-scale and often personal dynamics taking place wthin the broader process of urbanisation. Such cases emphasize the central rôle of individual actors in reacting to and reifying the forces of urban transformation through their private construction activities.

Economic Growth: New Problems and New Risks

2006 ◽  
pp. 20-37 ◽  
Author(s):  
M. Ershov
Keyword(s):  
Economic Growth ◽  
Foreign Exchange ◽  
Driving Force ◽  
Structural Changes ◽  
Rate Of Growth

The economic growth, which is underway in Russia, raises new questions to be addressed. How to improve the quality of growth, increasing the role of new competitive sectors and transforming them into the driving force of growth? How can progressive structural changes be implemented without hampering the rate of growth in general? What are the main external and internal risks, which may undermine positive trends of development? The author looks upon financial, monetary and foreign exchange aspects of the problem and comes up with some suggestions on how to make growth more competitive and sustainable.

Questions on the role of biofilms for the adaptation of microorganisms to unfavorable environmental factors by the example of P. aeruginosa

2020 ◽  
Vol 99 (4) ◽  
pp. 379-383
Author(s):  
Vasily N. Afonyushkin ◽  
N. A. Donchenko ◽  
Ju. N. Kozlova ◽  
N. A. Davidova ◽  
V. Yu. Koptev ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Environmental Factors ◽  
Barrier Function ◽  
Infectious Agent ◽  
Antagonistic Activity ◽  
The Body ◽  
Main Function ◽  
Pathogenic Potential ◽  
The Face

Pseudomonas aeruginosa is a widely represented species of bacteria possessing of a pathogenic potential. This infectious agent is causing wound infections, fibrotic cystitis, fibrosing pneumonia, bacterial sepsis, etc. The microorganism is highly resistant to antiseptics, disinfectants, immune system responses of the body. The responses of a quorum sense of this kind of bacteria ensure the inclusion of many pathogenicity factors. The analysis of the scientific literature made it possible to formulate four questions concerning the role of biofilms for the adaptation of P. aeruginosa to adverse environmental factors: Is another person appears to be predominantly of a source an etiological agent or the source of P. aeruginosa infection in the environment? Does the formation of biofilms influence on the antibiotic resistance? How the antagonistic activity of microorganisms is realized in biofilm form? What is the main function of biofilms in the functioning of bacteria? A hypothesis has been put forward the effect of biofilms on the increase of antibiotic resistance of bacteria and, in particular, P. aeruginosa to be secondary in charcter. It is more likely a biofilmboth to fulfill the function of storing nutrients and provide topical competition in the face of food scarcity. In connection with the incompatibility of the molecular radii of most antibiotics and pores in biofilm, biofilm is doubtful to be capable of performing a barrier function for protecting against antibiotics. However, with respect to antibodies and immunocompetent cells, the barrier function is beyond doubt. The biofilm is more likely to fulfill the function of storing nutrients and providing topical competition in conditions of scarcity of food resources.

The Modern Aristotle: Michael Polanyi’s Search for Truth against Nihilism

2018 ◽  
Author(s):  
Ronald Hoinski ◽  
Ronald Polansky
Keyword(s):  
Philosophy Of Science ◽  
Modern Science ◽  
Michael Polanyi ◽  
Contemporary Philosophy ◽  
The Face ◽  
Human Desire ◽  
The Mind ◽  
Theoretical Science

David Hoinski and Ronald Polansky’s “The Modern Aristotle: Michael Polanyi’s Search for Truth against Nihilism” shows how the general tendencies of contemporary philosophy of science disclose a return to the Aristotelian emphasis on both the formation of dispositions to know and the role of the mind in theoretical science. Focusing on a comparison of Michael Polanyi and Aristotle, Hoinski and Polansky investigate to what degree Aristotelian thought retains its purchase on reality in the face of the changes wrought by modern science. Polanyi’s approach relies on several Aristotelian assumptions, including the naturalness of the human desire to know, the institutional and personal basis for the accumulation of knowledge, and the endorsement of realism against objectivism. Hoinski and Polansky emphasize the promise of Polanyi’s neo-Aristotelian framework, which argues that science is won through reflection on reality.

Expansion of borders in the Kurdistan region and local and regional positions

2019 ◽  
Vol 3 (11) ◽  
pp. 1
Author(s):  
Harith Qahtan Abdullah ◽  
Abbas Fadel Atwan
Keyword(s):  
Middle East ◽  
Central Government ◽  
Kurdistan Region ◽  
War On Terrorism ◽  
National State ◽  
The Face ◽  
In The Beginning

The borders of Kurdistan represent an important point in Kurdish thought. They represent the hope of establishing their national state. The circumstances of the war on terrorism in Iraq and Syria have led to the emergence of what is known as a "propaganda" and the formation of a global front in its struggle. And with the signs of the collapse of the Syrian state and the weakness of the Iraqi state in the face of the "dashing" in the beginning. These circumstances led to the emergence of the role of the Kurdistan region in the confrontation "ISIS" and maintain the administrative border in the three provinces of Kurdistan in addition to the province of Kirkuk. That the circumstances of the war on terrorism created new international conditions on the Middle East arena, which will generate many problems between the Kurdistan region and the central government of Baghdad, as well as other problems between the region, Syria, Turkey and Iran. The war on terrorism has made countries free to fight the opposition groups under the name Terrorism by their classification. The Turkish side is fighting the PKK within the borders of the Kurdistan region, and this war can develop in a post-"warlike" phase. The war in Syria is also contradictory to vision and not resolved to a specific side and Iran's position on developments is encouraging.

FAITH–BASED COMMUNITIES AND POLITICS IN DULLSTROOM-EMNOTWENI: LOCAL STORIES OF IDENTITY

2016 ◽  
Vol 1 (1) ◽  
pp. 45-57 ◽  
Author(s):  
Christina Landman
Keyword(s):  
Higher Education ◽  
Service Delivery ◽  
Special Focus ◽  
Traditional Role ◽  
Cultural Conflicts ◽  
Local Identities ◽  
Political Interests ◽  
Local Municipality ◽  
The Face

A majority of the black community of Dullstroom-Emnotweni in the Mpumalanga highveld in the east of South Africa trace their descent back to the southern Ndebele of the so-called ‘Mapoch Gronden’, who lost their land in the 1880s to become farm workers on their own land. A hundred years later, in 1980, descendants of the ‘Mapoggers’ settled in the newly built ‘township’ of Dullstroom, called Sakhelwe, finding jobs on the railways or as domestic workers. Oral interviews with the inhabitants of Sakhelwe – a name eventually abandoned in favour of Dullstroom- Emnotweni – testify to histories of transition from landowner to farmworker to unskilled labourer. The stories also highlight cultural conflicts between people of Ndebele, Pedi and Swazi descent and the influence of decades of subordination on local identities. Research projects conducted in this and the wider area of the eMakhazeni Local Municipality reveal the struggle to maintain religious, gender and youth identities in the face of competing political interests. Service delivery, higher education, space for women and the role of faith-based organisations in particular seem to be sites of contestation. Churches and their role in development and transformation, where they compete with political parties and state institutions, are the special focus of this study. They attempt to remain free from party politics, but are nevertheless co-opted into contra-culturing the lack of service delivery, poor standards of higher education and inadequate space for women, which are outside their traditional role of sustaining an oppressed community.

Sign in / Sign up

Export Citation Format

Share Document