biological phenomenon
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2022 ◽  
Author(s):  
Ayalur Raghu Subbalakshmi ◽  
Bazella Ashraf ◽  
Mohit Kumar Jolly

Abstract The Epithelial-Mesenchymal Transition (EMT) is a biological phenomenon associated with explicit phenotypic and molecular changes in cellular traits. Unlike the earlier-held popular belief of it being a binary process, EMT is now thought of as a landscape including diverse hybrid E/M phenotypes manifested by varying degrees of the transition. These hybrid cells can co-express both epithelial and mesenchymal markers and/or functional traits, and can possess the property of collective cell migration, enhanced tumor-initiating ability, and immune/targeted therapy-evasive features, all of which are often associated with worse patient outcomes. These characteristics of the hybrid E/M cells have led to a surge in studies that map their biophysical and biochemical hallmarks that can be helpful in exploiting their therapeutic vulnerabilities. This review discusses recent advances made in investigating hybrid E/M phenotype(s) from diverse biophysical and biochemical aspects by integrating live cell-imaging, cellular morphology quantification and mathematical modelling, and highlights a set of questions that remain unanswered about the dynamics of hybrid E/M states.


Forests ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 31
Author(s):  
Huifang Zheng ◽  
Miaomiao Cai ◽  
Yucong Bai ◽  
Junlei Xu ◽  
Yali Xie ◽  
...  

Guttation is the process of exudating droplets from the tips, edges, and adaxial and abaxial surfaces of the undamaged leaves. Guttation is a natural and spontaneous biological phenomenon that occurs in a wide variety of plants. Despite its generally positive effect on plant growth, many aspects of this cryptic process are unknown. In this study, the guttation phenomenon characteristic of bamboo shoots and the anatomical feature of these and culm sheaths were systematically observed. In addition, the water transport pathway and the compounds in guttation droplets of bamboo shoots were analyzed, and the effect of bamboo sheaths’ guttation on the growth of bamboo shoots was assessed. The results revealed that bamboo shoots began to exudate liquid in the evening through to the next morning, during which period the volume of guttation liquid gradually increases and then decreases before sunrise. Many vascular bundles are in bamboo shoots and culm sheaths to facilitate this water transport. The exudate liquid contains organic acids, sugars, and hormones, among other compounds. Our findings suggest that the regular guttation of the sheath blade is crucial to maintain the normal growth of bamboo shoots.


2021 ◽  
Vol 1 (1) ◽  
pp. 155-161
Author(s):  
James Becvar ◽  

The important chemical and biological phenomenon of osmosis is depicted in a sequence of photographs. Sugar placed on a cut tomato half becomes wet and then dissolves in water withdrawn from the tomato cells by the process of osmosis.


2021 ◽  
pp. 1-11
Author(s):  
Anja Marschall

Abstract This paper questions the conventional interpretation of the doe-comparison in Ps 42:1 based on linguistic indications and a biological phenomenon. When the verb ערג is considered as a form of crying out and not of longing, it can be recognised that the næpæš is not only trying to reach God but is also constructively influencing the praying person towards this goal. This leads to a new perspective on the self-perception of the praying person and the role of the næpæš throughout the prayer. After initially rejecting the needs of the næpæš, in the last stanza, the praying person is finally transforming the performative screaming into formulated prayer: lament, petition, and praise. By turning to lament they are taking up the doe’s call and vindicating the næpæš’s intentions as essential and justified expressions of the self.


2021 ◽  
Author(s):  
Alona Botnar ◽  
Grant Lawrence ◽  
Steven P. Maher ◽  
Amèlie Vantaux ◽  
Benoît Witkowski ◽  
...  

Malaria is a major global health problem which predominantly afflicts developing countries. Although many antimalarial therapies are currently available, the protozoan parasite causing this disease, Plasmodium spp., continues to evade eradication efforts. One biological phenomenon hampering eradication efforts is the ability of. the parasite to arrest development, transform into a drug-insensitive form, and then resume growth post-therapy. Currently, the mechanisms by which the parasite enters arrested development, or dormancy, and later recrudesces or reactivates to continue development, are unknown and the malaria field lacks techniques to study these elusive mechanisms. Since Plasmodium spp. salvage purines for DNA synthesis, we hypothesized that alkyne-containing purine nucleosides could be used to develop a DNA synthesis marker which could be used to investigate mechanisms behind dormancy. Using copper-catalyzed click chemistry methods, we observe incorporation of alkyne modified adenosine, inosine, and hypoxanthine in actively replicating asexual blood stages of P. falciparum and incorporation of modified adenosine in actively replicating liver stage schizonts of P. vivax. Notably, these modified purines were not incorporated in dormant liver stage hypnozoites, suggesting this marker could be used as a tool to differentiate replicating and non-replicating liver forms and, more broadly, a tool for advancing our understanding Plasmodium dormancy mechanisms.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ryota Takaki ◽  
Atreya Dey ◽  
Guang Shi ◽  
D. Thirumalai

AbstractCondensation of hundreds of mega-base-pair-long human chromosomes in a small nuclear volume is a spectacular biological phenomenon. This process is driven by the formation of chromosome loops. The ATP consuming motor, condensin, interacts with chromatin segments to actively extrude loops. Motivated by real-time imaging of loop extrusion (LE), we created an analytically solvable model, predicting the LE velocity and step size distribution as a function of external load. The theory fits the available experimental data quantitatively, and suggests that condensin must undergo a large conformational change, induced by ATP binding, bringing distant parts of the motor to proximity. Simulations using a simple model confirm that the motor transitions between an open and a closed state in order to extrude loops by a scrunching mechanism, similar to that proposed in DNA bubble formation during bacterial transcription. Changes in the orientation of the motor domains are transmitted over ~50 nm, connecting the motor head and the hinge, thus providing an allosteric basis for LE.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xilin Wu ◽  
Yan Liu ◽  
Yaowei Zhang ◽  
Ran Gu

Heterosis is a common biological phenomenon in nature. It substantially contributes to the biomass yield and grain yield of plants. Moreover, this phenomenon results in high economic returns in agricultural production. However, the utilization of heterosis far exceeds the level of theoretical research on this phenomenon. In this review, the recent progress in research on heterosis in plants was reviewed from the aspects of classical genetics, parental genetic distance, quantitative trait loci, transcriptomes, proteomes, epigenetics (DNA methylation, histone modification, and small RNA), and hormone regulation. A regulatory network of various heterosis-related genes under the action of different regulatory factors was summarized. This review lays a foundation for the in-depth study of the molecular and physiological aspects of this phenomenon to promote its effects on increasing the yield of agricultural production.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tatiana A. Korshunova ◽  
Floor M. F. Driessen ◽  
Bernard E. Picton ◽  
Alexander V. Martynov

AbstractSpecies identification is a key procedure for broad-scoped ecological, phylogeographic and evolutionary studies. However, to perform a taxonomic study in the molecular era is a complicated task that has many pitfalls. In the present study we use particular examples of common but difficult to distinguish European species within the genus of Polycera (Nudibranchia, Mollusca) to discuss the general issues of the “cryptic species” problem that has broad biological and interdisciplinary importance and can significantly impede ecological, evolutionary, and other biodiversity-related research. The largest dataset of molecular and morphological information for European nudibranchs ever applied encompasses a wide geographical area and shapes a robust framework in this study. Four species are recognized in the species complex, including a new one. It is shown that a lack of appropriate taxonomic analysis led recently to considerable errors in species identity assessment of this complex. Chromatic polymorphism for each species is mapped in a periodic-like framework and combined with statistical analysis of the diagnostic features that considerably facilitates identification of particular species in the complex for biologists and practitioners. The present study evidently shows that “cryptic” and “non-cryptic” components are present within the same species. Therefore, this species complex is well suited for the exploring and testing of general biological problems. One of the main conclusions of this study is that division of biological diversity into “cryptic” and “non-cryptic” components is counterproductive. We propose that the central biological phenomenon of a species can instead be universally designated as multilevel organismal diversity thereby provide a practical set of methods for its investigation.


2021 ◽  
Author(s):  
Carlos Montemayor ◽  
Marc Wittmann

Philosophers and scientists alike often endorse the view that the passage of time is an illusion. Here we instead account for the phenomenology of passage as a real psycho-biological phenomenon. We argue that the experience of time passage has a real and measurable basis as it arises from an internal generative model for anticipating upcoming events. The experience of passage is not representation by a passive recipient of sensory stimulation but is generated by predictive processes of the brain and proactive sensorimotor activity of the whole body. The biological basis of the passage of time has not been examined in the metaphysics of time or the epistemology of time perception from a scientific perspective. This paper proposes to remedy this omission.


Author(s):  
Subbalakshmi Ayalur Raghu ◽  
Bazella Ashraf ◽  
Mohit Kumar Jolly

The Epithelial- Mesenchymal Transition (EMT) is a biological phenomenon associated with explicit phenotypic and molecular changes in cellular traits. Unlike the earlier-held popular belief of it being a binary process, EMT is now thought of as a landscape including diverse hybrid E/M phenotypes manifested by varying degrees of the transition. These hybrid cells can co-express both epithelial and mesenchymal markers and/or functional traits, and can possess the property of collective cell migration, enhanced tumor-initiating ability, and immune/targeted therapy-evasive features, all of which are often associated with worse patient outcomes. These characteristics of the hybrid E/M cells have led to a surge in studies that map their biophysical and biochemical hallmarks that can be helpful in exploiting their therapeutic vulnerabilities. This review discusses recent advances made in investigating hybrid E/M phenotype(s) from diverse biophysical and biochemical aspects by integrating live cell-imaging, cellular morphology quantification and mathematical modeling, and highlights a set of questions that remain unanswered about the dynamics of hybrid E/M states.


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