scholarly journals On the reproductive mechanisms of Gram-positive protocells

2021 ◽  
Author(s):  
Dheeraj Kanaparthi ◽  
Marko Lampe ◽  
Falk Hildebrand ◽  
Thomas Boesen ◽  
Andreas Klingl ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Evolutionary Significance ◽  
Early Earth ◽  
Biological Processes ◽  
Gram Positive ◽  
Reproductive Process ◽  
Daughter Cells ◽  
Self Assembling ◽  
Multi Stage ◽  
Reproductive Processes

AbstractBacterial protoplasts are believed to reproduce in a haphazard manner. Their unregulated method of reproduction is considered the simplest of all known forms of cell replication. In the present study, we attempted to understand the evolutionary significance and physiochemical mechanisms behind this process. Here we transformed a Gram-positive bacterium into sack of cytoplasm, incapable of regulating either its morphology or reproductive processes. As such primitive (proto)cells devoid of molecular biological processes could have been native to early Earth, we grew these cells under environmental conditions of early Earth. We then monitored these cells at regular intervals to understand if they can grow and reproduce under these conditions. In our incubations, cells exhibited a multi-stage reproductive cycle resulting in viable daughter cells. What was previously thought to be a chaotic reproductive process, could in fact be well explained from a physicochemical perspective. Both morphology and reproductive process of these cells were determined by chemical and self-assembling properties of their cell constituents rather than the information encoded in their genome. Despite its haphazard appearance, we propose that the reproductive process of bacterial protoplasts is better optimized for environmental conditions of early Earth and could be reminiscent of protocell reproductive processes.Abstract Figure

scholarly journals On the reproductive mechanism of Gram-negative protocells

2021 ◽  
Author(s):  
Dheeraj Kanaparthi ◽  
Marko Lampe ◽  
Baoli Zhu ◽  
Andreas Klingl ◽  
Tillmann Lueders ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Reproductive Cycle ◽  
Environmental Conditions ◽  
Living Cell ◽  
Early Earth ◽  
Experimental Conditions ◽  
Gram Negative ◽  
Daughter Cells ◽  
Multi Stage ◽  
Reproductive Processes

Protocells are thought to have existed on early Earth before the origin of prokaryotes. These primitive cells are believed to have carried out processes like replication solely based on the physicochemical properties of their cell constituents. Despite considerable efforts, replication of a living cell-driven entirely by laws of physics and chemistry has never been achieved. To test this hypothesis, we transformed extant bacteria into sacks of cytoplasm, incapable of regulating either their morphology or reproductive processes. We then exposed these proxy-protocells (bacterial protoplasts) to presumed Archaean Eon environmental conditions to understand if or how these cells reproduce. Contrary to the current presumption that bacterial protoplasts reproduce in a haphazard manner, under our experimental conditions they reproduced via a multi-stage reproductive cycle, resulting in viable daughter cells. Our observations suggest that this mechanism of reproduction could in fact be well explained from a biophysical perspective. Based on our observations we argue that this method of reproduction is better suited for the environmental conditions of early Earth.

A postulate to assess ‘habitability’

2004 ◽  
Vol 3 (2) ◽  
pp. 157-163 ◽  
Author(s):  
Charles S. Cockell ◽  
Frances Westall
Keyword(s):  
Environmental Conditions ◽  
Early Earth ◽  
Earth Environment ◽  
Chemical Conditions ◽  
Physical And Chemical ◽  
Early Earth Environment

One principal challenge in biology is defining a postulate by which the habitability of other planets can be assessed. Current assessments suffer from two potential weaknesses. With respect to other planets, either assumptions are made about the physical and chemical conditions of environments that err on the side of biological optimism without empirical constraint by spacecraft observations or novel physiologies of microorganisms are invented to fit extraterrestrial environmental conditions with no demonstrated microbiological counterparts on Earth. Attempts to assess the habitability of the early Earth suffer from similar problems. We discuss the following postulate: ‘the proposition that a planet is or was habitable requires that the physiological requirements of microorganisms on Earth known at the time of assessment match the empirically determined combined physical and chemical conditions in the extraterrestrial or early Earth environment being assessed’ as a means of evaluating ‘habitability’. We use as tests for our postulate the early Earth and the cloud deck of Venus (a habitat that has been a source of optimistic debate for forty years). We conclude that, although the early Earth was habitable, Venus is a dead world.

The Human Body is a Pressurized Self-Assembly Machine

2012 ◽  
Author(s):  
Brenda K. Krkosska Bayles
Keyword(s):  
Blood Pressure ◽  
Human Body ◽  
Self Assembly ◽  
The Novel ◽  
Daughter Cells ◽  
Self Assembling ◽  
Living Tissues ◽  
First Time

The novel and self-obtained concept of this paper is that living tissues get help self-assembling by following some mechanical equations. The simple diagnostic act of checking someone’s blood pressure reminds us that the human body is a pressurized object, and blood moving throughout the pressurized body creates flows that are strikingly similar to the movements of fluids in pressurized machines. Self-assembly using two mechanical concepts and their equations is herein demonstrated for the first time to show the separation of healthy daughter cells and the nonseparation of aneuploid cells, and to show monosaccharide and disaccharide movements.

Compensatory reactions of populations to stresses, and their evolutionary significance.

1954 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
AJ Nicholson
Keyword(s):  
Population Density ◽  
Adverse Effects ◽  
Environmental Conditions ◽  
Lucilia Cuprina ◽  
Evolutionary Significance ◽  
Age Group ◽  
Evolutionary Progress ◽  
Compensatory Reaction ◽  
Compensatory Reactions

Cultures of Lucilia cuprina which were subjected to different kinds and intensities of stress automatically accommodated themselves to these stresses and maintained themselves in a state of balance under all the varied environmental conditions provided. Compensatory reaction always counteracted in some degree the adverse effects of the stresses to which the insects were subjected. Thus the persistent destruction of a particular age-group always caused more individuals to reach this age, so reducing the effects produced by destruction upon population density. It is shown that density governed compensatory reaction is a necessary counterpart of selection in evolutionary progress.

scholarly journals Swansong biospheres II: the final signs of life on terrestrial planets near the end of their habitable lifetimes

2014 ◽  
Vol 13 (3) ◽  
pp. 229-243 ◽  
Author(s):  
Jack T. O'Malley-James ◽  
Charles S. Cockell ◽  
Jane S. Greaves ◽  
John A. Raven
Keyword(s):  
Environmental Conditions ◽  
Late Stage ◽  
Cloud Cover ◽  
Main Sequence ◽  
Interaction Model ◽  
Early Earth ◽  
Sequence Evolution ◽  
The Sun ◽  
Upper Limit ◽  
Life On Earth

AbstractThe biosignatures of life on Earth do not remain static, but change considerably over the planet's habitable lifetime. Earth's future biosphere, much like that of the early Earth, will consist of predominantly unicellular microorganisms due to the increased hostility of environmental conditions caused by the Sun as it enters the late stage of its main sequence evolution. Building on previous work, the productivity of the biosphere is evaluated during different stages of biosphere decline between 1 and 2.8 Gyr from present. A simple atmosphere–biosphere interaction model is used to estimate the atmospheric biomarker gas abundances at each stage and to assess the likelihood of remotely detecting the presence of life in low-productivity, microbial biospheres, putting an upper limit on the lifetime of Earth's remotely detectable biosignatures. Other potential biosignatures such as leaf reflectance and cloud cover are discussed.

scholarly journals The concept of translocational regulation

2008 ◽  
Vol 182 (2) ◽  
pp. 225-232 ◽  
Author(s):  
Ramanujan S. Hegde ◽  
Sang-Wook Kang
Keyword(s):  
Endoplasmic Reticulum ◽  
Membrane Protein ◽  
Conceptual Framework ◽  
Environmental Conditions ◽  
Protein Translocation ◽  
Regulatory Control ◽  
Biological Processes ◽  
Mechanistic Understanding

Biological processes are regulated to provide cells with exquisite adaptability to changing environmental conditions and cellular demands. The mechanisms regulating secretory and membrane protein translocation into the endoplasmic reticulum (ER) are unknown. A conceptual framework for translocational regulation is proposed based on our current mechanistic understanding of ER protein translocation and general principles of regulatory control.

scholarly journals Depsipeptide nucleic acids: prebiotic formation, oligomerization, and self-assembly of a new candidate proto-nucleic acid

2020 ◽  
Author(s):  
David M. Fialho ◽  
Suneesh C. Karunakaran ◽  
Katherine W. Greeson ◽  
Isaac Martínez ◽  
Gary B. Schuster ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Self Assembly ◽  
Rna World ◽  
Chemical Components ◽  
Early Earth ◽  
New Class ◽  
Self Assembling ◽  
World Hypothesis ◽  
Rna World Hypothesis

AbstractThe mechanism by which genetic polymers spontaneously formed on the early Earth is currently unknown. The RNA World hypothesis implies that RNA oligomers were produced prebiotically, but the demonstration of this process has proven challenging. Alternatively, RNA may be the product of evolution and some, or all, of its chemical components may have been preceded by functionally analogous moieties that were more readily accessible under plausible early-Earth conditions. We report a new class of nucleic acid analog, depsipeptide nucleic acid, which displays several properties that make it an attractive candidate for the first informational polymer to arise on the Earth. The monomers of depsipeptide nucleic acids can form under plausibly prebiotic conditions. These monomers oligomerize spontaneously when dried from aqueous solutions to form nucleobase-functionalized depsipeptides. Once formed, these depsipeptide nucleic acid oligomers are capable of complementary self-assembly, and are resistant to hydrolysis in the assembled state. These results suggest that the initial formation of primitive, self-assembling, informational polymers may have been relatively facile.

scholarly journals A Study of Bio-Computational Design in Terms of Enhancing Water Absorption by Method of Bionics Within the Architectural Fields

2021 ◽  
pp. 102-113
Author(s):  
Gang Mao
Keyword(s):  
Water Absorption ◽  
Environmental Conditions ◽  
Three Dimensional ◽  
Computational Design ◽  
Computational Studies ◽  
Biological Processes ◽  
Design Strategies ◽  
Capillary Action ◽  
3D Print ◽  
Material Conditions

AbstractThis essay aims to explore an architecture computational design intended to accept and absorb moisture through geometrical and material conditions, and using design strategies, help deliver this moisture upwards through capillary action to areas of cryptogamic growth including mosses and smaller ferns on the surface of architecture. The purpose of this research project is to explore the morphology of general capillary systems based on research into the principle of xylematic structures in trees, thereby creating a range of capillary designs using three types of material: plaster, 3D print plastic, and concrete. In addition, computational studies are used to examine various types of computational designs of organic structures, such as columns, driven by physical and environmental conditions such as sunshine, shade, tides and other biological processes to explore three-dimensional particle-based branching systems that define both structural and water delivery paths.

scholarly journals On the nature of the earliest known lifeforms

2021 ◽  
Author(s):  
Dheeraj Kanaparthi ◽  
Marko Lampe ◽  
Baoli Zhu ◽  
Thomas Boesen ◽  
Andreas Klingl ◽  
...  
Keyword(s):  
Cell Membrane ◽  
Energy Conservation ◽  
Cell Morphology ◽  
Environmental Conditions ◽  
Phylogenetic Group ◽  
Biological Processes ◽  
Biological Mechanisms

AbstractOldest known microfossils were known to have the most complex of morphologies among prokaryotes. Given the morphology of an organism is governed by information encoded in its genome, it was proposed that these primitive organisms most likely possessed complex molecular biological processes. Here we worked with bacterial protoplasts under environmental conditions of Archaean earth and reproduced morphologies of every known microfossil and associated structures. Contrary to the current presumption, our work suggest that complex morphologies of these microfossils could be explained not by presence but by complete absence of molecular biological mechanisms. Environmental conditions and architecture of the cell membrane are the only factors that determined the morphology of these organisms. Based on our observations we present a case for reinterpretation of Archaean microfossils as protocells that were devoid of complex molecular biological processes rather than annotating them to a particular phylogenetic group of extant bacteria.One Sentence SummaryMicrofossils reported from Archaean BIF’s most likely were liposome like protocells, which had evolved mechanisms for energy conservation, but not for regulating cell morphology and replication.

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