Desiccation Phase Research Articles

Lacustrine sedimentation by powerful storm waves in Gale crater and its implications for a warming episode on Mars

This investigation documents that the Rugged Terrain Unit, the Stimson formation, and the Greenheugh sandstone were deposited in a 1200 m-deep lake that formed after the emergence of Mt. Sharp in Gale crater, Mars, nearly 4 billion years ago. In fact, the Curiosity rover traversed on a surface that once was the bottom of this lake and systematically examined the strata that were deposited in its deepest waters on the crater floor to layers that formed along its shoreline on Mt. Sharp. This provided a rare opportunity to document the evolution of one aqueous episode from its inception to its desiccation and to determine the warming mechanism that caused it. Deep water lacustrine siltstones directly overlie conglomerates that were deposited by mega floods on the crater floor. This indicates that the inception phase of the lake was sudden and took place when flood waters poured into the crater. The lake expanded quickly and its shoreline moved up the slope of Mt. Sharp during the lake-level rise phase and deposited a layer of sandstone with large cross beds under the influence of powerful storm waves. The lake-level highstand phase was dominated by strong bottom currents that transported sediments downhill and deposited one of the most distinctive sedimentological features in Gale crater: a layer of sandstone with a 3 km-long field of meter-high subaqueous antidunes (the Washboard) on Mt. Sharp. Bottom current continued downhill and deposited sandstone and siltstone on the foothills of Mt. Sharp and on the crater floor, respectively. The lake-level fall phase caused major erosion of lacustrine strata that resulted in their patchy distribution on Mt. Sharp. Eroded sediments were then transported to deep waters by gravity flows and were re-deposited as conglomerate and sandstone in subaqueous channels and in debris flow fans. The desiccation phase took place in calm waters of the lake. The aqueous episode we investigated was vigorous but short-lived. Its characteristics as determined by our sedimentological study matches those predicted by an asteroid impact. This suggests that the heat generated by an impact transformed Mars into a warm, wet, and turbulent planet. It resulted in planet-wide torrential rain, giant floods on land, powerful storms in the atmosphere, and strong waves in lakes. The absence of age dates prevents the determination of how long the lake existed. Speculative rates of lake-level change suggest that the lake could have lasted for a period ranging from 16 to 240 Ky.

Effects of the Desiccation Duration on the Dynamic Responses of Biofilm Metabolic Activities to Rewetting

Global climate changes have increased the duration and frequency of river flow interruption, affecting the physical and community structure of benthic biofilms. However, the dynamic responses of biofilm metabolism during the dry-wet transition remain poorly understood. Herein, the dynamic changes in biofilm metabolic activities were investigated through mesocosm experiments under short-term (25 day) and long-term drought (90 day), followed by a 20 day rewetting. The biofilm ecosystem metabolism, as measured by gross primary production and community respiration, was significantly inhibited and turned heterotrophic during the desiccation phase and then recovered, becoming autotrophic during the rewetting period regardless of the desiccation periods due to the high resilience of the autotrophic community. However, long-term drought decreased the recovery rate of the ecosystem metabolism and also caused irreparable damage to the biofilm carbon metabolism, measured using Biolog Eco Plates. Specifically, the recovery of the total carbon metabolic activity is related to the specific carbon source utilized by biofilm microorganisms, such as polymers, carbohydrates, and carboxylic acids. However, the divergent changes of amino acids caused the failure of the total carbon metabolism in long-term drought treatments to recover to the control level even after 20 days of rewetting. This research provides direct evidence that the increased duration of non-flow periods affects biofilm-mediated carbon biogeochemical processes.

Glycerol and natural sugar-derived complex modulate differentially stratum corneum water-binding properties and structural parameters in an in vitro Raman-desorption model.

The epidermal protective functions are closely associated with skin hydration homeostasis. The understanding of different states of water binding is a rising concept in assessing topically applied formulations and their interaction within the stratum corneum (SC). In addition to global water content, primary bound water, partially bound water, and unbound water and barrier-related lipid lateral packing and protein secondary structure can be measured by Raman spectroscopy. This study aimed to establish an in vitro SC model to evaluate differences in the efficacy of a natural sugar-derived complex in combination with glycerol and a botanical extract in modulating SC water binding and structural proteins and barrier lipids. These compounds were selected due to their water-binding and soothing properties. The SC water profiles were assessed at the surface and in 8μm SC depth. After a 12-hour hyperhydration and subsequent product incubation the measurements were performed during a 6hours desiccation phase. The maximal water caption and the time until reaching a steady state are measured as well as water retention and resistance against water loss. Global water content, partially bound, and unbound water, as well as lipid and protein structures were assessed with confocal Raman microspectroscopy. Both the natural sugar-derived mixture and more pronounced, the same mixture with additional glycerol increased all three water-binding parameters at the surface and in 8μm SC depth at the beginning and during the desiccation phase. Further addition of botanical extract did not result in an additional increase of the water-binding. All three formulations showed an increase in the lipid lateral packing values prevented the protein alteration as measured by β-sheets signal compared to blank. The present model is suited for screening studies comparing the specific effects of different compounds on hydration states. The natural sugar-derived mixture Aquaxyl showed evidence for an improvement of all SC hydration states, lipid and protein structure which was further enhanced by the addition of glycerol 5%. This improvement was evidenced at the surface and within the SC for all hydration-related parameters, and the lipid as well the protein structures. The addition of botanical extract phytoessence blue daisy did not show further improvement.

A simple method to purify intrinsically disordered proteins by adjusting trichloroacetic acid concentration

Late embryogenic abundant proteins (LEA) are a group of proteins that accumulate during the desiccation phase of the seed and in response to water deficit in the plant. Most LEA proteins are highly hydrophilic and have physicochemical characteristics similar to those of intrinsically disordered proteins (IDPs). Although the function of LEA proteins is not fully understood, there is evidence indicating that these proteins have an important role in reducing the effects caused by water limitation. The analysis of the biochemical and physicochemical characteristics of LEA proteins is crucial to determine their function, for which it is necessary to obtain large amounts of pure protein. Within this current work, we have improved our previous TCA purification method used for basic recombinant LEA proteins to obtain acidic IDPs, the method reported here is fast and simple and is based on the enrichment of the protein of interest by boiling of the bacterial extract followed by a precipitation with different concentrations of TCA and salt. This protocol was applied to acidic and basic IDPs, represented by eight recombinant LEAs, resulting in milligram quantities of highly enriched proteins, which keep their in vitro functionality.

The humidity level matters during the desiccation of Norway spruce somatic embryos.

In Norway spruce, as in many other conifers, the germination capacity of somatic embryos is strongly influenced by the desiccation phase inserted after maturation. The intensity of drying during desiccation eminently affected the formation of emblings (i.e., seedlings developed from somatic embryos). Compared to non-desiccated embryos, the germination capacity of embryos desiccated at 100% relative humidity was about three times higher, but the reduction of relative humidity to 95 and 90% had a negative effect on the subsequent embryo development. The water loss observed in these embryos did not lead to an increase in lipid peroxidation, as shown by malondialdehyde levels. Another metabolic pathway in plants that mediates a response to abiotic stresses is directed toward the biosynthesis of polyamines (PAs). The activities of PA biosynthetic enzymes increased steadily in embryos during desiccation at 100% relative humidity, whereas they decreased at lower humidity. The total content of free PAs in the embryos gradually decreased throughout desiccation. The increase in free putrescine (Put) and perchloric acid-insoluble Put conjugates was observed in embryos desiccated at lower humidity. These changes were accompanied to some extent by the transcription of the genes for the PA biosynthesis enzymes. Desiccation at 100% relative humidity increased the activity of the cell wall-modifying enzymes β-1,3-glucanases and chitinases; the activities of these enzymes were also significantly suppressed at reduced humidity. The same pattern was observed in the transcription of some β-1,3-glucanase and chitinase genes. Desiccation treatments triggered metabolic processes that responded to water availability, suggesting an active response of the embryo to the reduction in humidity. A positive effect was demonstrated only for desiccation at high relative humidity. Some of the physiological characteristics described can be used as markers of inappropriate relative humidity during somatic embryo desiccation.

Micromorphological investigations on the sediment-fill of an early Neolithic well in Northwestern-Saxony, Germany

Within Neolithic settlements in Central Europe most sediments have been preserved in pits and trenches. Wells as deep pits provide a large set of information about their construction, usage and backfill history. Seven wells were discovered close to a Linear Pottery Culture (german: Linienbandkeramik = LBK) settlement 15 km south of the city of Leipzig (Germany). For the excavation of a rather small and less sophisticated well construction archaeological methods were complemented by micromorphological analyses of the sediments within the well to gain more detailed information about its backfill history. By the help of thin section analysis, it was possible to draw a distinction between different sedimentation processes. The method helped to identify desiccation phases and events of sediment inflow into the wells case. Moreover, we were able to obtain indications that the well was probably not used for drinking water extraction but for other domestic purposes requiring water.

Desiccation as a Post-maturation Treatment Helps Complete Maturation of Norway Spruce Somatic Embryos: Carbohydrates, Phytohormones and Proteomic Status.

Exposure of Norway spruce (Picea abies) somatic embryos and those of many other conifers to post-maturation desiccation treatment significantly improves their germination. An integration analysis was conducted to understand the underlying processes induced during the desiccation phase at the molecular level. Carbohydrate, protein and phytohormone assays associated with histological and proteomic studies were performed for the evaluation of markers and actors in this phase. Multivariate comparison of mature somatic embryos with mature desiccated somatic embryos and/or zygotic embryos provided new insights into the processes involved during the desiccation step of somatic embryogenesis. Desiccated embryos were characterized by reduced levels of starch and soluble carbohydrates but elevated levels of raffinose family oligosaccharides. Desiccation treatment decreased the content of abscisic acid and its derivatives but increased total auxins and cytokinins. The content of phytohormones in dry zygotic embryos was lower than in somatic embryos, but their profile was mostly analogous, apart from differences in cytokinin profiles. The biological processes “Acquisition of desiccation tolerance”, “Response to stimulus”, “Response to stress” and “Stored energy” were activated in both the desiccated somatic embryos and zygotic embryos when compared to the proteome of mature somatic embryos before desiccation. Based on the specific biochemical changes of important constituents (abscisic acid, raffinose, stachyose, LEA proteins and cruciferins) induced by the desiccation treatment and observed similarities between somatic and zygotic P. abies embryos, we concluded that the somatic embryos approximated to a state of desiccation tolerance. This physiological change could be responsible for the reorientation of Norway spruce somatic embryos toward a stage suitable for germination.

Феномен пульсирующих озёр Торея (Забайкалье)

The phenomenon of pulsating lakes of the drainless Torey Basin - Barun- and Zun-Torey, located in the south of Transbaikalia territory, is considered. The unique peculiarity of the lakes is periodicity, mainly alternation of distinctly dry and wet periods with the duration of 24 to 42 years, on average about 30 years, i.e. a strict cyclicity is not observed. The cause of periodicity is measured from two main positions: either climatic changes or tectonic processes. The analysis of the available material indicates that the cause of periodicity is complex, but with the leading role of tectonic processes (neotectonic fluctuations), awakening multilevel groundwater of the Tsasucheisky and Torey artesian basins are the main sources of lake feeding. Groundwater feeding (Uldza River, Imalka River) is insignificant and the inflow is spent for evaporation. Tectonic processes do not occur without the participation of the Space (solar activity, the state of the Universe), because the Earth is a coordinated space system and all the processes occurring in it are reflected in the state of its depths. Measures are suggested to change considerably the duration of oscillations of the water surface of the Torey lakes and not to wait for the next water period of 15 years and more. Such measures can be compulsory influence on the activity of a lot of underground waters of the artesian basin, the main sources of feeding of the lakes. External influences can be ground or underground dosed explosions or vibration (during desiccation phases), widely used to increase the oil and gas flow rate in hydrocarbon production. Another remarkable phenomenon of the Torey Basin is mud volcanism in a form of salsa, which some researchers consider as search signs of oil and gas bearing capacity. The analysis of materials on mud volcanism on a global scale unequivocally indicates the absence of mud volcanism not only in the Torey Basin, but also in general the absence of such in Transbaikalia. The phenomenon of pulsating Torey lakes is not related to climatic changes, but has a complex cause, with the leading end, the "piston pump" effect, not without the participation of the Space. There is no mud volcanism in the Torey Basin. Consequently, it is not necessary to speak about its prospects for oil-and-gas bearing capacity. The salts observed in the Torey have a different nature and are connected with the activity of groundwater in the areas of permafrost spreading

Phosphorus Leaching From Naturally Structured Forest Soils Is More Affected by Soil Properties Than by Drying and Rewetting

Foliar phosphorus (P) concentrations in beech trees are decreasing in Europe, potentially leading to reductions in the trees’ growth and vitality. In the course of climate change, drying and rewetting (DRW) cycles in forest soils are expected to intensify. As a consequence, P leakage from the root zone may increase due to temporarily enhanced organic matter mineralization. We addressed the questions whether sites with different soil properties, including P pools, differ in their susceptibility to DRW-induced P leaching, and whether this is affected by the DRW intensity. A greenhouse experiment was conducted on naturally structured soil columns with beech saplings from three sites representing a gradient of soil P availability. Four DRW cycles were conducted by air-drying and irrigating the soils over 4 hours (fast rewetting) or 48 hours (slow rewetting). Leachates below the soil columns were analyzed for total P, and molybdate reactive P (considered as inorganic P). The difference was considered to represent organically bound P. Boosted regression trees were used to examine the effects of DRW and soil characteristics on P leaching. Contrary to a first hypothesis, that P leaching increases upon rewetting with the intensity of the preceding desiccation phase, intense soil drying (to pF 3.5 to 4.5) did not generally increase P leakage compared to moderate drying (to pF 2 to 3). However, we observed increased inorganic P concentrations and decreased organic P concentrations in leachates after drying to matric potentials above pF 4. Also against our expectations, fast rewetting did not lead to higher leakage of P than slow rewetting. However, the results confirmed our third hypothesis that the site poorest in P, where P recycling is mainly limited to the humus layer and the uppermost mineral soil, lost considerably more P during DRW than the other two sites. The results of our experiment with naturally structured soils imply that intensified drying and rewetting cycles, as predicted by climate-change scenarios, may not per se lead to increased P leaching from forest soils. Soil properties such as soil organic carbon content and texture appear to be more important predictors of P losses.

The Messinian Salinity Crisis in Mallorca: New insights for a Western Mediterranean stratigraphic scenario

The Messinian Salinity Crisis (MSC) was an extraordinary geological event that affected the whole Mediterranean region, as well as global marine circulation between 5.97 and 5.33 Ma. In the Mediterranean, the crisis was mainly characterized by isolation from the Atlantic Ocean, resulting in a new hydrological budget leading to the accumulation of large amounts of evaporites and large-scale erosion of its margins. The nature of the majority of the evaporites and erosional surfaces is still unknown, thus representing a challenge which forms the subject of debate in the scientific community.The Neogene Mallorca basins (Balearic Islands) are well situated to provide a stratigraphic record which expresses the sequence of events related to the MSC, being especially suitable for testing possible geological models or scenarios. New research on the island of Mallorca provides data about the MSC and Zanclean reflooding in the central part of the Western Mediterranean (Balearic Basin), with obvious repercussions for both academia and industry.The main aim of this study is to describe the features which characterize sedimentation during the Miocene-Pliocene transition on the island of Mallorca, to establish how this stratigraphic record relates to the different proposed MSC scenarios for the whole of the Mediterranean. In this regard, a stratigraphic analysis was carried out on a total of 100 exposures and boreholes corresponding to the Neogene basins of Mallorca. The results indicate that, on the island of Mallorca, the development of the MSC is most consistent with models that represent the main phase of desiccation occurring after the accumulation of marginal evaporites (Primary Lower Gypsum), the Terminal Carbonate Complex and the Lago Mare deposits.

Peptide-Bound Methionine Sulfoxide (MetO) Levels and MsrB2 Abundance Are Differentially Regulated during the Desiccation Phase in Contrasted Acer Seeds.

Norway maple and sycamore produce desiccation-tolerant (orthodox) and desiccation-sensitive (recalcitrant) seeds, respectively. Drying affects reduction and oxidation (redox) status in seeds. Oxidation of methionine to methionine sulfoxide (MetO) and reduction via methionine sulfoxide reductases (Msrs) have never been investigated in relation to seed desiccation tolerance. MetO levels and the abundance of Msrs were investigated in relation to levels of reactive oxygen species (ROS) such as hydrogen peroxide, superoxide anion radical and hydroxyl radical (•OH), and the levels of ascorbate and glutathione redox couples in gradually dried seeds. Peptide-bound MetO levels were positively correlated with ROS concentrations in the orthodox seeds. In particular, •OH affected MetO levels as well as the abundance of MsrB2 solely in the embryonic axes of Norway maple seeds. In this species, MsrB2 was present in oxidized and reduced forms, and the latter was favored by reduced glutathione and ascorbic acid. In contrast, sycamore seeds accumulated higher ROS levels. Additionally, MsrB2 was oxidized in sycamore throughout dehydration. In this context, the three elements •OH level, MetO content and MsrB2 abundance, linked together uniquely to Norway maple seeds, might be considered important players of the redox network associated with desiccation tolerance.

Ontogenetic shifts and interspecies variation in tolerance to desiccation and heat at the early benthic phase of six intertidal invertebrates

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 634:15-28 (2020) - DOI: https://doi.org/10.3354/meps13189 Ontogenetic shifts and interspecies variation in tolerance to desiccation and heat at the early benthic phase of six intertidal invertebrates Hilary J. Hamilton, Louis A. Gosselin* Department of Biological Sciences, Thompson Rivers University, 805 TRU Way, Kamloops, BC, V2C 0C8, Canada *Corresponding author: lgosselin@tru.ca ABSTRACT: During the early benthic phase of intertidal invertebrates, desiccation and elevated temperature are increasingly recognized as the most significant stressors, but it is not known whether all species are equally sensitive during this phase. In this study, involving 6 co-occurring rocky intertidal species (Nucella ostrina, Littorina scutulata, Mytilus trossulus, Chthamalus dalli, Balanus glandula, Petrolisthes cinctipes), we examined interspecific variation in (1) tolerance to desiccation and temperature at the early benthic phase and (2) the magnitude of ontogenetic shifts in tolerance. Ontogenetic shifts in temperature tolerance were significant but modest, whereas desiccation tolerance thresholds changed considerably throughout ontogeny in all species, and shifts were greatest in species that changed microhabitats during ontogeny. Tolerance at the early benthic phase also varied markedly among species; temperature tolerance thresholds ranged from 32.3 to 45.8°C, and juveniles were able to survive exposure to desiccation for durations ranging from 10 min to 29 h. Ontogenetic shifts in desiccation tolerance were largely explained by differences in body mass; thus individuals achieve increased tolerance through growth. However, variation among species was unrelated to body mass; rather, interspecific variation in tolerance thresholds of the early benthic phase was related to the upper limit of intertidal distribution of the species and to microhabitat use during this phase. The study revealed desiccation to be a greater threat to early benthic phase individuals than temperature in all species, but also discovered considerable interspecific differences in tolerance thresholds, such that species are likely to respond differently to present and future extremes in desiccation and temperature. KEY WORDS: Ontogenetic shifts · Tolerance threshold · Early benthic phase · Juveniles · Environmental stress · Mortality factors · Microhabitat use · Interspecific variation Full text in pdf format Supplementary material PreviousNextCite this article as: Hamilton HJ, Gosselin LA (2020) Ontogenetic shifts and interspecies variation in tolerance to desiccation and heat at the early benthic phase of six intertidal invertebrates. Mar Ecol Prog Ser 634:15-28. https://doi.org/10.3354/meps13189 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 634. Online publication date: January 23, 2020 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2020 Inter-Research.

Effects of Rate of Drying, Life History Phase, and Ecotype on the Ability of the Moss Bryum Argenteum to Survive Desiccation Events and the Influence on Conservation and Selection of Material for Restoration

Desiccation stress is frequently experienced by the moss Bryum argenteum and can influence survival, propagation and niche selection. We attempted to disentangle the interacting factors of life history phase (five categories) and rate of desiccation (time allotted for induction of desiccation tolerance) for thirteen ecotypes of B. argenteum. Using chlorophyll fluorescence as a stress index, we determined how these parameters influenced desiccation tolerance. Rate of drying and life phase significantly affected desiccation tolerance. The reaction norms of desiccation tolerance displayed by the thirteen ecotypes showed a substantial degree of variation in phenotypic plasticity. We observed differences in survival and fluorescence between rapid and slow drying events in juveniles. These same drying applications did not produce as large of a response for adult shoots (which consistently displayed high values). Some juvenile and protonemal ecotypes, such as those from the southwest United States, possessed higher innate tolerance to rapid drying, and greater resilience compared to ecotypes sourced from mesic localities in the United States. These results show a complex nuanced response to desiccation with ecotypes displaying a range of responses to desiccation reflecting both inherently different capacities for tolerating desiccation as well as variation in capacity for phenotypic plasticity. Our results suggest that we should expect few short-term effects of climate change due to high desiccation tolerance of adult shoots, but significant adverse long-term effects on colony establishment due to low tolerance of protonema and juvenile shoots. Further, we would recommend that future studies using mosses for habitat restoration of aridlands consider the desiccation tolerance capacity of individual ecotypes used for cultivation and later re-introduction. Understanding how mosses respond to desiccation is essential to interpret ecological roles, habitat preferences, selective pressures, and responses to climate change, and to estimate the potential effects of climate changes on bryophyte species and populations.

Fruit Development and ABA Biosynthesis During Caryocar brasiliense (Caryocaraceae) Seed Maturation

Little is currently known about the interactions between structural and physiological factors in Neotropical fruit development. We sought to characterize fruit development and the dynamics of ABA biosynthesis during seed maturation in Caryocar brasiliense, a tree species endemic to the Cerrado biome of Brazil. Biometric evaluations were made of both the pericarp and seed during fruit development. ABA1, NCED4, and NCED9 expression were evaluated in embryonic tissues during seed maturation, as well as anatomical, histochemical, and ultrastructural evaluations, in vitro and ex vitro embryo cultures, and ABA quantifications. Fruit development demonstrated three stages: histodifferentiation (0–40 days after anthesis—DAA); endocarp maturation (40–60 DAA); and the conclusion of mesocarp and seed maturation (60–90 DAA). The embryos showed early degrees of differentiation: hypocotyl expansion, development of the leaf primordia, and vascularization. Seed maturation occurred (from 40 DAA) concomitantly with the development of endocarp aculei in four phases influenced by ABA dynamics. The beginning of reserve deposition and the acquisition of dehydration tolerance were related to increases in extra-embryonic ABA. ABA biosynthesis at the radicular pole was related to increased reserve deposition and dehydration tolerance (which was not associated with the occurrence of a desiccation phase). The maturation of C. brasiliense seeds is influenced by embryonic and extra-embryonic ABA, and the dormancy of the pyrenes results from the interaction of the effects of that hormone and pericarp tissue.

Identification and transcriptional profile of Lactobacillus paracasei genes involved in the response to desiccation and rehydration

Lactobacillus paracasei is able to persist in a variety of natural and technological environments despite physico-chemical perturbations, in particular alternations between desiccation and rehydration. However, the way in which it adapts to hydric fluctuations and the genetic determinants involved are not clearly understood. To identify the genes involved in adaptation to desiccation, an annotated library of L. paracasei random transposon mutants was screened for viability after desiccation (25% relative humidity, 25 °C). We found 16 genes that have not been described as being involved in this response. Most of them are linked to either the transport of molecules or to cell wall structure and function. Our screening also identified genes encoding DNA related enzymes and an alarmone necessary for L. paracasei survival. Subsequently, the expression of the identified genes was measured at five stages of the dehydration-rehydration process to decipher the chronology of genetic mechanisms. They were classified into four different transcriptional profiles: genes upregulated during both desiccation and rehydration phases, genes upregulated during the desiccation phase only, genes downregulated during both desiccation and rehydration and genes downregulated only during the rehydration stage. Thus, genetic response to hydric fluctuations seems to occur during desiccation and can continue or not during rehydration. The genes identified should contribute to improve the stabilization of Lactobacillus starters in dry state.

Transcriptome analysis of the anhydrobiotic cell line Pv11 infers the mechanism of desiccation tolerance and recovery

The larvae of the African midge, Polypedilum vanderplanki, can enter an ametabolic state called anhydrobiosis to overcome fatal desiccation stress. The Pv11 cell line, derived from P. vanderplanki embryo, shows desiccation tolerance when treated with trehalose before desiccation and resumes proliferation after rehydration. However, the molecular mechanisms of this desiccation tolerance remain unknown. Here, we performed high-throughput CAGE-seq of mRNA and a differentially expressed gene analysis in trehalose-treated, desiccated, and rehydrated Pv11 cells, followed by gene ontology analysis of the identified differentially expressed genes. We detected differentially expressed genes after trehalose treatment involved in various stress responses, detoxification of harmful chemicals, and regulation of oxidoreduction that were upregulated. In the desiccation phase, L-isoaspartyl methyltransferase and heat shock proteins were upregulated and ribosomal proteins were downregulated. Analysis of differentially expressed genes during rehydration supported the notion that homologous recombination, nucleotide excision repair, and non-homologous recombination were involved in the recovery process. This study provides initial insights into the molecular mechanisms underlying the extreme desiccation tolerance of Pv11 cells.

Embryonal life histories: Desiccation plasticity and diapause in the Argentinean pearlfish Austrolebias bellottii.

Embryos of annual killifish diapause in soil egg banks while ponds are dry. Their rates of development and survival in different developmental stages determine the numbers and stages of embryos at rewetting. In the Argentinean pearlfish Austrolebias bellottii, we investigated plasticity for desiccation in such embryonal life history components across phases of mild desiccation and rewetting and also effects of life history on hatching. In comparison with nonannuals, our data suggest that incidences of diapause have become relatively independent of the occurrence of desiccation, as if they have become genetically assimilated. We found limited survival effects of desiccation, limited developmental delays, and an acceleration of development into the prehatching stage. This response can be adaptive when desiccation informs that an opportunity to hatch approaches. Embryos arrest development in the prehatching stage (diapause DIII) or in the dispersed‐cell phase (diapause DI). Parental pair variation in rates of development and survival in the earliest developmental stages affects the fraction of embryos that are in DI at rewetting and the number surviving. Given such effects on life history fitness components, rates during embryonal development seem "visible" to selection and the developmental system can thus adapt when pair variation contains a heritable component. In agreement with expectations for the presence of diversified bet‐hedging, some embryos hatched and others not in over half of the clutches with several developed embryos at the moment of rewetting. Hatching probabilities increased for eggs produced later in the experiment, and they increased when embryos were rewetted a second time after two months. This response is opposite of what is expected when age‐dependent hatching would be adapted to exploit opportunities for completing another generation before the dry season.

Temporal transcriptome profiling of developing seeds reveals a concerted gene regulation in relation to oil accumulation in Pongamia (Millettia pinnata)

BackgroundPongamia (Millettia pinnata syn. Pongamia pinnata), an oilseed legume species, is emerging as potential feedstock for sustainable biodiesel production. Breeding Pongamia for favorable traits in commercial application will rely on a comprehensive understanding of molecular mechanism regulating oil accumulation during its seed development. To date, only limited genomic or transcript sequences are available for Pongamia, while a temporal transcriptome profiling of developing seeds is still lacking in this species.ResultsIn this work, we conducted a time-series analysis of morphological and physiological characters, oil contents and compositions, as well as global gene expression profiles in developing Pongamia seeds. Firstly, three major developmental phases were characterized based on the combined evidences from embryonic shape, seed weight, seed moisture content, and seed color. Then, the gene expression levels at these three phases were quantified by RNA-Seq analyses with three biological replicates from each phase. Nearly 94% of unigenes were expressed at all three phases, whereas only less than 2% of unigenes were exclusively expressed at one of these phases. A total of 8881 differentially expressed genes (DEGs) were identified between phases. Furthermore, the qRT-PCR analyses for 10 DEGs involved in lipid metabolism demonstrated a good reliability of our RNA-Seq data in temporal gene expression profiling. We observed a dramatic increase in seed oil content from the embryogenesis phase to the early seed-filling phase, followed by a steady and moderate increase towards the maximum at the desiccation phase. We proposed that a highly active expression of most genes related to fatty acid (FA) and triacylglycerol (TAG) biosynthesis at the embryogenesis phase might trigger both the substantial oil accumulation and the membrane lipid synthesis for rapid cell proliferation at this phase, while a concerted reactivation of TAG synthesis-related genes at the desiccation phase might further promote storage lipid synthesis to achieve the maximum content of seed oils.ConclusionsThis study not only built a bridge between gene expression profiles and oil accumulation in developing seeds, but also laid a foundation for future attempts on genetic engineering of Pongamia varieties to acquire higher oil yield or improved oil properties for biofuel applications.

Investigation of the processes of the acoustic apparatus with the processing technological environment power interaction

The physical picture of the processes of the apparatus with the processing technological environment interaction is determined, the change in its rheological properties were taken into account. The effectiveness of cavitation effects from the initial to the final processing stage is caused by the contact pressure and the speed of its propagation. A lot of power characteristics and parameters were considered for the effective implementation of the cavitation process. On the basis of these parameters, the energy of the process is accumulated by expanding the bubble from the initial balanced to its maximum radius. The basis of accumulation is the tensile forces in the phase of desiccation of the acoustic wave. The graphs of the contact pressure dependence on the key parameters of the process and the determination of the regularity of its change are made. The modes and parameters for leakage of energy-efficient acoustic process of different environments processing were proposed. The directions of of research results application and their further development were determined

The effect of polyploidization on tree hydraulic functioning

Recent research has highlighted the importance of living tissue in wood. Polyploidization can impact amounts and arrangements of living cells in wood, potentially leading to increased drought tolerance. Tetraploid variants were created from the apple cultivar Malus ×domestica 'Gala' (Gala-4x), and their vulnerability to drought-induced cavitation and their hydraulic capacitance were compared to those of their diploid predecessors (Gala-2x). Assuming a positive correlation between polyploidy and drought tolerance, we hypothesized lower vulnerability and higher capacitance for the tetraploid. Vulnerability to drought-induced cavitation and the hydraulic capacitance were quantified through acoustic emission and continuous weighing of shoots during a bench-top dehydration experiment. To underpin the hydraulic trait results, anatomical variables such as vessel area, conduit diameter, cell wall reinforcement, and ray and vessel-associated parenchyma were measured. Vulnerability to drought-induced cavitation was intrinsically equal for both ploidy variants, but Gala-4x proved to be more vulnerable than Gala-2x during the early phase of desiccation as was indicated by its significantly lower air entry value. Higher change in water content of the leafy shoot, higher amount of parenchyma, and larger vessel area and size resulted in a significantly higher hydraulic capacitance and efficiency for Gala-4x compared to Gala-2x. Both ploidy variants were typified as highly sensitive to drought-induced cavitation, with no significant difference in their overall drought vulnerability. But, when water deficit is short and moderate, Gala-4x may delay a drought-induced decrease in performance by trading hydraulic safety for increased release of capacitively stored water from living tissue.