Desiccation of plants is often lethal but is tolerated by the majority of seeds and by vegetative tissues of only a small number of land plants. Desiccation tolerance is an ancient trait, lost from ...vegetative tissues following the appearance of tracheids but reappearing in several lineages when selection pressures favored its evolution. Cells of all desiccation-tolerant plants and seeds must possess a core set of mechanisms to protect them from desiccation- and rehydration-induced damage. This review explores how desiccation generates cell damage and how tolerant cells assuage the complex array of mechanical, structural, metabolic, and chemical stresses and survive.Likewise, the stress of rehydration requires appropriate mitigating cellular responses. We also explore what comparative genomics, both structural and responsive, have added to our understanding of cellular protection mechanisms induced by desiccation, and how vegetative desiccation tolerance circumvents destructive, stress-induced cell senescence.
Resurrection plants, which are the “gifts” of natural evolution, are ideal models for studying the genetic basis of plant desiccation tolerance. Here, we report a high-quality genome assembly of 301 ...Mb for the diploid spike moss Selaginella tamariscina, a primitive vascular resurrection plant. We predicated 27 761 protein-coding genes from the assembled S. tamariscina genome, 11.38% (2363) of which showed significant expression changes in response to desiccation. Approximately 60.58% of the S. tamariscina genome was annotated as repetitive DNA, which is an almost 2-fold increase of that in the genome of desiccation-sensitive Selaginella moellendorffii. Genomic and transcriptomic analyses highlight the unique evolution and complex regulations of the desiccation response in S. tamariscina, including species-specific expansion of the oleosin and pentatricopeptide repeat gene families, unique genes and pathways for reactive oxygen species generation and scavenging, and enhanced abscisic acid (ABA) biosynthesis and potentially distinct regulation of ABA signaling and response. Comparative analysis of chloroplast genomes of several Selaginella species revealed a unique structural rearrangement and the complete loss of chloroplast NAD(P)H dehydrogenase (NDH) genes in S. tamariscina, suggesting a link between the absence of the NDH complex and desiccation tolerance. Taken together, our comparative genomic and transcriptomic analyses reveal common and species-specific desiccation tolerance strategies in S. tamariscina, providing significant insights into the desiccation tolerance mechanism and the evolution of resurrection plants.
We report the genome sequence of a diploid Selaginella tamariscina with high heterozygosity. We reveal species-specific expansion and contraction of gene families in the nuclear genome, unique structural rearrangement and gene losses in the chloroplast genome, and altered expression of genes, which are related to resurrection physiology in S. tamariscina. This study provides significant insights into desiccation tolerance mechanism and the evolution of resurrection plants.
Resurrection of the Dead Susannah Ticciati
St Andrews Encyclopaedia of Theology,
04/2023
Journal Article
Peer reviewed
Open access
This article explores the Christian notion of the resurrection of the dead under four headings: finality, individuality, communality and hope. For each, it takes its starting point in 1 Corinthians ...15, and from there explores the debates and controversies associated with each basic affirmation, drawing from ancient and modern authors across the tradition, with reference to some of the key scriptural texts. Under the heading of finality the article explores, first, the question of whether the resurrection restores an original perfection or rather brings about a new creation which exceeds the first; and second, whether death is a natural good or the consequence of sin. It argues for the finality of the resurrection as that which lends life on earth decisive and conclusive significance. Under the heading of individuality it explores patristic and medieval debates concerning the persistence of matter at the resurrection, and modern counterparts to these debates, whether in experiments in artificial intelligence or in contemporary gender discourse, arguing that the real significance of these discussions lies in the question of the nature of the good. Under the heading of communality it explores the question of whether all or only some are raised to salvation, and of whether the resurrection concerns only human beings or all living creatures, concluding that a focus on the extent of the resurrection’s inclusivity should give way to a focus on the communal character of resurrection life. Under the heading of hope it offers a liberationist response to the Nietzschean critique that belief in an afterlife entails a denial of this life.
A variety of Southern African resurrection plants were surveyed using high-throughput cell wall profiling tools. Species evaluated were the dicotyledons, Myrothamnus flabellifolia and Craterostigma ...plantagineum; the monocotyledons, Xerophyta viscosa, Xerophyta schlecterii, Xerophyta humilis and the resurrection grass Eragrostis nindensis, as well as a pteridophyte, the resurrection fern, Mohria caffrorum. Comparisons were made between hydrated and desiccated leaf and frond material, with respect to cell wall composition and polymer abundance, using monosaccharide composition analysis, FT-IR spectroscopy and comprehensive microarray polymer profiling in combination with multivariate data analysis. The data obtained suggest that three main functional strategies appear to have evolved to prepare plant cell walls for desiccation. Arabinan-rich pectin and arabinogalactan proteins are found in the resurrection fern M. caffrorum and the basal angiosperm M. flabellifolia where they appear to act as 'pectic plasticizers'. Dicotyledons with pectin-rich walls, such as C. plantagineum, seem to use inducible mechanisms which consist of up-regulating wall proteins and osmoprotectants. The hemicellulose-rich walls of the grass-like Xerophyta spp. and the resurrection grass E. nindensis were found to contain highly arabinosylated xylans and arabinogalactan proteins. These data support a general mechanism of 'plasticising' the cell walls of resurrection plants to desiccation and implicate arabinose-rich polymers (pectin-arabinans, arabinogalactan proteins and arabinoxylans) as the major contributors in ensuring flexibility is maintained and rehydration is facilitated in these plants.
Premise
Understanding the adaptive capacities of species over long timescales lies in examining the revived recent and millennia‐old resting spores buried in sediments. We show for the first time the ...revival, viability, and germination rate of resting spores of the diatom Chaetoceros deposited in sub‐seafloor sediments from three ages (recent: 0 to 80 years; ancient: ~1250 (Medieval Climate Anomaly) and ~6600 (Holocene Thermal Maximum) calendar year before present.
Methods
Recent and ancient Chaetoceros spores were revived to examine their viability and germination rate. Light and scanning electron microscopy and Sanger sequencing was done to identify the species.
Results
We show that ~6600 cal. year BP old Chaetoceros resting spores are still viable and that the vegetative reproduction in recent and ancient resting spores varies. The time taken to germinate is three hours to 2 to 3 days in both recent and ancient spores, but the germination rate of the spores decreased with increasing age. The germination rate of the recent spores was ~41% while that of the ancient spores were ~31% and ~12% for the ~1250 and ~6600 cal. year BP old resting spores, respectively. Based on the morphology of the germinated vegetative cells we identified the species as Chaetoceros muelleri var. subsalsum. Sanger sequences of nuclear and chloroplast markers identified the species as Chaetoceros muelleri.
Conclusions
We identify a unique model system, Chaetoceros muelleri var. subsalsum and show that recent and ancient resting spores of the species buried in sediments in the Baltic Sea can be revived and used for long‐term evolutionary studies.
Dining on Leviathan. Discoursing with Socrates. Debating the nature of existence in the afterlife. These are among the topics authors address in this wide-ranging account of how Jews have ...conceptualized the world to come and structured their lives in this world accordingly. Some authorities portrayed the afterlife as an endless round of feasting and drinking of chazerie that would put the fanciest Las Vegas buffets to shame. There were visionaries who mapped out otherworldly climes populated by monstrous creatures. Others, decidedly more staid, saw the world to come as a location where neither food nor wine would be consumed; instead, it would offer the opportunity to bring moral certitude to questionable practices that could not be eradicated in this world. More down to earth are comparisons between Rabbi Akiva and Socrates, and analyses of influential thinkers like Moses Mendelssohn and Emmanuel Levinas. And more practical are discussions of how concepts of the afterlife serve to determine mourning practices, or more broadly, how humans should fashion their lives in the here and now. The chronological range of these chapters also is impressive. The earliest documents discussed are from Apocryphal literature, including apocalypses, that were composed from 400 BCE to 200 CE. There are creative analyses of rabbinic material and documents from the medieval period through the twentieth century. Evolving ritual and liturgical practices bring readers up to the early twenty-first century. Each of the thirteen authors whose works are brought together in this volume shows historical, cultural, and religious sensitivity both to the unique features of these differing manifestations and to the elements that unite them. For the readers of this volume, which is equally rewarding for general audiences and for specialists, the result is a carefully nuanced, creatively balanced exploration of the breadth of Jewish thought and practice concerning some of the most profound and perplexing issues humans face.
Xerophyta humilis is a poikilochlorophyllous monocot resurrection plant used as a model to study vegetative desiccation tolerance. Dehydration imposes tension and ultimate loss of integrity of ...membranes in desiccation sensitive species. We investigated the predominant molecular species of glycerolipids present in root and leaf tissues, using multiple reaction monitoring mass spectrometry, and then analysed changes therein during dehydration and subsequent rehydration of whole plants. The presence of fatty acids with long carbon chains and with odd numbers of carbons were detected and confirmed by gas chromatography. Dehydration of both leaves and roots resulted in an increase in species containing polyunsaturated fatty acids and a decrease in disaturated species. Upon rehydration, lipid saturation was reversed, with this being initiated immediately upon watering in roots but only 12–24 hr later in leaves. Relative levels of species with short‐chained odd‐numbered saturated fatty acids decreased during dehydration and increased during rehydration, whereas the reverse trend was observed for long‐chained fatty acids. X. humilis has a unique lipid composition, this report being one of the few to demonstrate the presence of odd‐numbered fatty acids in plant phosphoglycerolipids.
Xerophyta humilis is a monocot resurrection plant used as a model to study vegetative desiccation tolerance. Dehydration of both leaves and roots resulted in an increase in species containing polyunsaturated fatty acids and a decrease in disaturated ones. Besides, we detected the presence of fatty acids with long carbon chains and with odd numbers of carbons in glycerolipids of this plant. Relative levels of lipid species with short‐chained odd‐numbered saturated fatty acids decreased during dehydration and increased during rehydration, whereas the reverse trend was observed for long‐chained fatty acids.
Despite extensive quantities of work with regard to reactivation of organophosphorus‐inhibited and aged acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), a new therapeutic solution has ...yet to be reached and current methods continue to rely on old oximes and management of the cholinergic crisis as the standard of care. For more information on the latest developments in this highly important field see the Review article by C. M. Hadad et al. on page 5337 ff.
PDF
