scholarly journals Transformation of Riccia fluitans, an Amphibious Liverwort Dynamically Responding to Environmental Changes

2020 ◽  
Vol 21 (15) ◽  
pp. 5410
Author(s):  
Felix Althoff ◽  
Sabine Zachgo
Keyword(s):  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Morphological Plasticity ◽  
Terrestrial Ecosystems ◽  
Transformation Protocol ◽  
Major Transition ◽  
Terrestrial Environments ◽  
History Of ◽  
Life On Earth ◽  
Colonization Of Land

The colonization of land by streptophyte algae, ancestors of embryophyte plants, was a fundamental event in the history of life on earth. Bryophytes are early diversifying land plants that mark the transition from freshwater to terrestrial ecosystems. The amphibious liverwort Riccia fluitans can thrive in aquatic and terrestrial environments and thus represents an ideal organism to investigate this major transition. Therefore, we aimed to establish a transformation protocol for R. fluitans to make it amenable for genetic analyses. An Agrobacterium transformation procedure using R. fluitans callus tissue allows to generate stably transformed plants within 10 weeks. Furthermore, for comprehensive studies spanning all life stages, we demonstrate that the switch from vegetative to reproductive development can be induced by both flooding and poor nutrient availability. Interestingly, a single R. fluitans plant can consecutively adapt to different growth environments and forms distinctive and reversible features of the thallus, photosynthetically active tissue that is thus functionally similar to leaves of vascular plants. The morphological plasticity affecting vegetative growth, air pore formation, and rhizoid development realized by one genotype in response to two different environments makes R. fluitans ideal to study the adaptive molecular mechanisms enabling the colonialization of land by aquatic plants.

scholarly journals Mechanisms of the Morphological Plasticity Induced by Phytohormones and the Environment in Plants

2021 ◽  
Vol 22 (2) ◽  
pp. 765
Author(s):  
Gaojie Li ◽  
Shiqi Hu ◽  
Xuyao Zhao ◽  
Sunjeet Kumar ◽  
Yixian Li ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Leaf Development ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Current Knowledge ◽  
Leaf Growth ◽  
Morphological Plasticity ◽  
Regulatory Elements ◽  
Leaf Morphogenesis ◽  
Environmental Signals

Plants adapt to environmental changes by regulating their development and growth. As an important interface between plants and their environment, leaf morphogenesis varies between species, populations, or even shows plasticity within individuals. Leaf growth is dependent on many environmental factors, such as light, temperature, and submergence. Phytohormones play key functions in leaf development and can act as molecular regulatory elements in response to environmental signals. In this review, we discuss the current knowledge on the effects of different environmental factors and phytohormone pathways on morphological plasticity and intend to summarize the advances in leaf development. In addition, we detail the molecular mechanisms of heterophylly, the representative of leaf plasticity, providing novel insights into phytohormones and the environmental adaptation in plants.

Adaptation, Transformation, and Development

2020 ◽  
Vol 42 (1) ◽  
pp. 5-20
Author(s):  
Allen Thompson ◽  
Keyword(s):  
Climate Change ◽  
Environmental Changes ◽  
Climate Adaptation ◽  
Natural Capital ◽  
Future Generations ◽  
Human Flourishing ◽  
Human Welfare ◽  
History Of ◽  
Superior Approach ◽  
Life On Earth

It is widely accepted that we must adapt to climate change. But we sit on the edge of radical, unprecedented, and rapid anthropogenic environmental changes that are driven by many factors in addition to greenhouse gas emissions. In this way, we occupy a unique and precarious position in the history of our species. Many basic conditions of life on Earth are changing at an alarming rate and thus we should begin to transform and broaden our thinking about adaptation. The conceptual history of climate adaptation intersects with conceptions of human development and sustainability, which provides a framework for adaptation in how we think about human flourishing and, subsequently, what it is to be human in the Anthropocene. If sustainability is about maintaining human welfare across generations but we acknowledge that climate change may undercut our ability to deliver as much and as good total or natural capital to subsequent generations, we have a residual duty to otherwise positively affect the welfare of future generations. A subjective, preference-based conception of human welfare is compared to an objective, capabilities-based approach and, while some adaptive preferences are unavoidable, embracing an objective theory of human flourishing provides a superior approach for meeting the residual duty we have to future generations by beginning the process of adapting our conception of human natural goodness, or what it is to be a good human being.

scholarly journals NO GAMETOPHORES 2 is a novel regulator of the 2D to 3D growth transition in the moss Physcomitrium patens

2020 ◽  
Author(s):  
Laura A. Moody ◽  
Steven Kelly ◽  
Roxaana Clayton ◽  
Zoe Weeks ◽  
David M. Emms ◽  
...  
Keyword(s):  
Physcomitrella Patens ◽  
Lignin Biosynthesis ◽  
Morphological Diversity ◽  
Feedback Mechanism ◽  
3 Dimensional ◽  
History Of ◽  
Acid Pathway ◽  
Life On Earth ◽  
Colonization Of Land ◽  
2D To 3D

SUMMARYThe colonization of land by plants was one of the most transformative events in the history of life on Earth. The transition from water, which coincided with and was likely facilitated by the evolution of 3-dimensional (3D) growth, enabled the generation of morphological diversity on land. In many plants, the transition from 2-dimensional (2D) to 3D growth occurs during embryo development. However, in the early divergent moss Physcomitrium patens (formerly Physcomitrella patens), 3D growth is preceded by an extended filamentous phase that can be maintained indefinitely. Here, we describe the identification of the cytokinin-responsive NO GAMETOPHORES 2 (PpNOG2) gene, which encodes a shikimate o- hydroxycinnamoyltransferase. In mutants lacking PpNOG2 function, transcript levels of CLAVATA and SCARECROW genes are significantly reduced, excessive gametophore initial cells are produced, and buds undergo premature developmental arrest. Our results suggest that PpNOG2 functions in the ascorbic acid pathway leading to cuticle formation, and that NOG2-related genes were co-opted into the lignin biosynthesis pathway after the divergence of bryophytes and vascular plants. We present a revised model of 3D growth in which PpNOG2 comprises part of a feedback mechanism that is required for the modulation of gametophore initial cell frequency. We also propose that the 2D to 3D growth transition in P. patens is underpinned by complex auxin-cytokinin crosstalk that is regulated, at least in part, by changes in flavonoid metabolism.

scholarly journals Selection for synchronized cell division in simple multicellular organisms

2018 ◽  
Author(s):  
Jason Olejarz ◽  
Kamran Kaveh ◽  
Carl Veller ◽  
Martin A. Nowak
Keyword(s):  
Cell Division ◽  
Natural Selection ◽  
Population Model ◽  
Natural Question ◽  
Cell Divisions ◽  
Major Transition ◽  
History Of ◽  
Selection For ◽  
Life On Earth ◽  
Multicellular Organisms

AbstractThe evolution of multicellularity was a major transition in the history of life on earth. Conditions under which multicellularity is favored have been studied theoretically and experimentally. But since the construction of a multicellular organism requires multiple rounds of cell division, a natural question is whether these cell divisions should be synchronous or not. We study a simple population model in which there compete simple multicellular organisms that grow either by synchronous or asynchronous cell divisions. We demonstrate that natural selection can act differently on synchronous and asynchronous cell division, and we offer intuition for why these phenotypes are generally not neutral variants of each other.

Conclusion

2017 ◽  
Author(s):  
Erin Lambert
Keyword(s):  
Dutch Reformed ◽  
Christian Life ◽  
The Reformation ◽  
History Of ◽  
Life On Earth

This conclusion offers a brief commentary on the implications of song, resurrection, and belief for the broader history of the Reformation. It relates the various uses of song by Lutherans (hymn pamphlets), Anabaptists (martyr songs), Dutch Reformed exiles (psalms), and Catholics (motets) to these confessions’ ideas of belief as it concerned resurrection and their understandings of how belief was bound up with the Christian life on earth. In place of a story of the transformation of one conception of Christianity to many different conceptions, this book as a whole suggests that the Reformation might be reconceived as a much more elemental debate about the role that belief was to play in a Christian life.

The Major Transitions in Evolution

1997 ◽  
Author(s):  
John Maynard Smith ◽  
Eors Szathmary
Keyword(s):  
Full Range ◽  
Evolution Of Cooperation ◽  
Major Transitions ◽  
Insect Societies ◽  
Wide Range ◽  
Major Transition ◽  
Life Itself ◽  
History Of ◽  
Emergence Of Cooperation ◽  
Multicellular Organisms

Over the history of life there have been several major changes in the way genetic information is organized and transmitted from one generation to the next. These transitions include the origin of life itself, the first eukaryotic cells, reproduction by sexual means, the appearance of multicellular plants and animals, the emergence of cooperation and of animal societies, and the unique language ability of humans. This ambitious book provides the first unified discussion of the full range of these transitions. The authors highlight the similarities between different transitions--between the union of replicating molecules to form chromosomes and of cells to form multicellular organisms, for example--and show how understanding one transition sheds light on others. They trace a common theme throughout the history of evolution: after a major transition some entities lose the ability to replicate independently, becoming able to reproduce only as part of a larger whole. The authors investigate this pattern and why selection between entities at a lower level does not disrupt selection at more complex levels. Their explanation encompasses a compelling theory of the evolution of cooperation at all levels of complexity. Engagingly written and filled with numerous illustrations, this book can be read with enjoyment by anyone with an undergraduate training in biology. It is ideal for advanced discussion groups on evolution and includes accessible discussions of a wide range of topics, from molecular biology and linguistics to insect societies.

scholarly journals Demographic history and genomic response to environmental changes in a rapid radiation of wild rats

2021 ◽  
Author(s):  
Deyan Ge ◽  
Anderson Feijó ◽  
Zhixin Wen ◽  
Alexei V Abramov ◽  
Liang Lu ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Demographic History ◽  
Terrestrial Ecosystems ◽  
Tibet Plateau ◽  
Global Changes ◽  
Rapid Radiation ◽  
Protein Functions ◽  
Wild Rats ◽  
Qinghai Tibet Plateau ◽  
Genomic Response

Abstract For organisms to survive and prosper in a harsh environment, particularly under rapid climate change, poses tremendous challenges. Recent studies have highlighted the continued loss of megafauna in terrestrial ecosystems and the subsequent surge of small mammals, such as rodents, bats, lagomorphs, and insectivores. However, the ecological partitioning of these animals will likely lead to large variation in their responses to environmental change. In the present study, we investigated the evolutionary history and genetic adaptations of white-bellied rats (Niviventer Marshall, 1976), which are widespread in the natural terrestrial ecosystems in Asia but also known as important zoonotic pathogen vectors and transmitters. The southeastern Qinghai-Tibet Plateau (QHTP) was inferred as the origin center of this genus, with parallel diversification in temperate and tropical niches. Demographic history analyses from mitochondrial and nuclear sequences of Niviventer demonstrated population size increases and range expansion for species in Southeast Asia, and habitat generalists elsewhere. Unexpectedly, population increases were seen in N. eha, which inhabits the highest elevation among Niviventer species. Genome scans of nuclear exons revealed that among the congeneric species, N. eha has the largest number of positively selected genes. Protein functions of these genes are mainly related to olfaction, taste and tumor suppression. Extensive genetic modification presents a major strategy in response to global changes in these alpine species.

scholarly journals Current understanding on the Cambrian Explosion: questions and answers

PalZ ◽  
2021 ◽  
Author(s):  
Xingliang Zhang ◽  
Degan Shu
Keyword(s):  
Environmental Changes ◽  
Size Variation ◽  
Progressive Increase ◽  
Cambrian Explosion ◽  
Time Interval ◽  
Early Cambrian ◽  
Ecological Processes ◽  
Questions And Answers ◽  
Evolutionary Event ◽  
History Of

AbstractThe Cambrian Explosion by nature is a three-phased explosion of animal body plans alongside episodic biomineralization, pulsed change of generic diversity, body size variation, and progressive increase of ecosystem complexity. The Cambrian was a time of crown groups nested by numbers of stem groups with a high-rank taxonomy of Linnaean system (classes and above). Some stem groups temporarily succeeded while others were ephemeral and underrepresented by few taxa. The high number of stem groups in the early history of animals is a major reason for morphological gaps across phyla that we see today. Most phylum-level clades achieved their maximal disparity (or morphological breadth) during the time interval close to their first appearance in the fossil record during the early Cambrian, whereas others, principally arthropods and chordates, exhibit a progressive exploration of morphospace in subsequent Phanerozoic. The overall envelope of metazoan morphospace occupation was already broad in the early Cambrian though it did not reach maximal disparity nor has diminished significantly as a consequence of extinction since the Cambrian. Intrinsic and extrinsic causes were extensively discussed but they are merely prerequisites for the Cambrian Explosion. Without the molecular evolution, there could be no Cambrian Explosion. However, the developmental system is alone insufficient to explain Cambrian Explosion. Time-equivalent environmental changes were often considered as extrinsic causes, but the time coincidence is also insufficient to establish causality. Like any other evolutionary event, it is the ecology that make the Cambrian Explosion possible though ecological processes failed to cause a burst of new body plans in the subsequent evolutionary radiations. The Cambrian Explosion is a polythetic event in natural history and manifested in many aspects. No simple, single cause can explain the entire phenomenon.

Memory impairment induced by amphetamine derivatives in laboratory animals and in humans: a review

2012 ◽  
Vol 3 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Jordi Camarasa ◽  
Teresa Rodrigo ◽  
David Pubill ◽  
Elena Escubedo
Keyword(s):  
Illicit Drugs ◽  
Molecular Mechanisms ◽  
Memory Performance ◽  
Laboratory Animals ◽  
Club Drugs ◽  
Synthetic Drugs ◽  
History Of ◽  
Amphetamine Derivatives ◽  
Considerable Body

AbstractThe 20th century brought with it the so-called club drugs (the most notorious being amphetamine derivatives), which are used by young adults at all-night dance parties. Methamphet­amine and 3,4-methylenedioxymethamphetamine (MDMA or ecstasy) are synthetic drugs with stimulant and psychoactive properties that belong to the amphetamine family. Here, we have reviewed the literature about the cognitive impairment induced by these two amphetamine derivatives and the preclinical and clinical outcomes. Although there is controversial evidence about the effect of methamphetamine and MDMA on learning and memory in laboratory animals, results from published papers demonstrate that amphetamines cause long-term impairment of cognitive functions. A large number of pharmacological receptors have been studied and screened as targets of amphetamine-induced cognitive dysfunction, and extensive research efforts have been invested to provide evidence about the molecular mechanisms behind these cognitive deficits. In humans, there is a considerable body of evidence indicating that methamphetamine and MDMA seriously disrupt memory and learning processes. Although an association between the impairments of memory performance and a history of recreational amphetamine ingestion has also been corroborated, a number of methodological difficulties continue to hamper research in this field, the most important being the concomitant use of other illicit drugs.

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