Pre-akinete formation in Zygnema sp. from polar habitats is associated with metabolite re-arrangement

Abstract In streptophytic green algae in the genus Zygnema, pre-akinete formation is considered a key survival strategy under extreme environmental conditions in alpine and polar regions. The transition from young, dividing cells to pre-akinetes is associated with morphological changes and the accumulation of storage products. Understanding the underlying metabolic changes could provide insights into survival strategies in polar habitats. Here, GC-MS-based metabolite profiling was used to study the metabolic signature associated with pre-akinete formation in Zygnema sp. from polar regions under laboratory conditions, induced by water and nutrient depletion, or collected in the field. Light microscopy and TEM revealed drastic changes in chloroplast morphology and ultrastructure, degradation of starch grains, and accumulation of lipid bodies in pre-akinetes. Accordingly, the metabolite profiles upon pre-akinete formation reflected a gradual shift in metabolic activity. Compared with young cells, pre-akinetes showed an overall reduction in primary metabolites such as amino acids and intermediates of the tricarboxylic acid (TCA) cycle, consistent with a lower metabolic turnover, while they accumulated lipids and oligosaccharides. Overall, the transition to the pre-akinete stage involves re-allocation of photosynthetically fixed energy into storage instead of growth, supporting survival of extreme environmental conditions.

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Potential of temperature- and salinity-driven shifts in diatom compatible solute concentrations to impact biogeochemical cycling within sea ice

Elem Sci Anth ◽

10.1525/elementa.421 ◽

2020 ◽

Vol 8 ◽

Cited By ~ 3

Author(s):

Hannah M. Dawson ◽

Katherine R. Heal ◽

Angela K. Boysen ◽

Laura T. Carlson ◽

Anitra E. Ingalls ◽

...

Keyword(s):

Sea Ice ◽

Compatible Solutes ◽

Biogeochemical Cycling ◽

Compatible Solute ◽

Arctic Sea Ice ◽

Polar Regions ◽

Antarctic Sea Ice ◽

Metabolite Profiles ◽

Metabolite Pool ◽

Cellular Metabolite

Sea-ice algae are an important source of primary production in polar regions, yet we have limited understanding of their responses to the seasonal cycling of temperature and salinity. Using a targeted liquid chromatography-mass spectrometry-based metabolomics approach, we found that axenic cultures of the Antarctic sea-ice diatom, Nitzschia lecointei, displayed large differences in their metabolomes when grown in a matrix of conditions that included temperatures of –1 and 4°C, and salinities of 32 and 41, despite relatively small changes in growth rate. Temperature exerted a greater effect than salinity on cellular metabolite pool sizes, though the N- or S-containing compatible solutes, 2, 3-dihydroxypropane-1-sulfonate (DHPS), glycine betaine (GBT), dimethylsulfoniopropionate (DMSP), and proline responded strongly to both temperature and salinity, suggesting complexity in their control. We saw the largest (> 4-fold) response to salinity for proline. DHPS, a rarely studied but potential compatible solute, had the highest intracellular concentrations among all compatible solutes of ~85 mM. When comparing the culture findings to natural Arctic sea-ice diatom communities, we found extensive overlap in metabolite profiles, highlighting the relevance of culture-based studies to probe environmental questions. Large changes in sea-ice diatom metabolomes and compatible solutes over a seasonal cycle could be significant components of biogeochemical cycling within sea ice.

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A Worm's World: Ecological Flexibility Pays Off for Free-Living Nematodes in Sediments and Soils

BioScience ◽

10.1093/biosci/biz086 ◽

2019 ◽

Vol 69 (11) ◽

pp. 867-876 ◽

Cited By ~ 4

Author(s):

Michaela Schratzberger ◽

Martijn Holterman ◽

Dick van Oevelen ◽

Johannes Helder

Keyword(s):

Environmental Conditions ◽

Food Sources ◽

Polar Regions ◽

Soil Processes ◽

Free Living ◽

Ecological Flexibility ◽

Ecological Success ◽

The Tropics ◽

Animal Communities ◽

The Impact

Abstract Free-living nematodes, an ancient animal phylum of unsegmented microscopic roundworms, have successfully adapted to nearly every ecosystem on Earth: from marine and freshwater to land, from the polar regions to the tropics, and from the mountains to the ocean depths. They are globally the most abundant animals in sediments and soils. In the present article, we identify the factors that collectively explain the successful ecological proliferation of free-living nematodes and demonstrate the impact they have on vital sediment and soil processes. The ecological success of nematodes is strongly linked to their ability to feed on various food sources that are present in both sediments and soils, and to proliferate rapidly and survive in contrasting environmental conditions. The adaptations, roles, and behaviors of free-living nematodes have important implications for the resilience of sediments and soils, and for emergent animal communities responding to human alterations to ecosystems worldwide.

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Rice leaves undergo a rapid metabolic reconfiguration during a specific stage of primordium development

10.1101/2021.12.01.470706 ◽

2021 ◽

Author(s):

Naomi Cox ◽

Heather J Walker ◽

James Pitman ◽

W Paul Quick ◽

Lisa M Smith ◽

...

Keyword(s):

Leaf Development ◽

Morphological Changes ◽

Leaf Growth ◽

Tca Cycle ◽

Cell Number ◽

Developmental Trajectory ◽

Epidermal Differentiation ◽

Rice Leaf ◽

Leaf Formation ◽

Developmental Index

Leaf development is crucial to establish the photosynthetic competency of plants. It is a process that requires coordinated changes in cell number, cell differentiation, transcriptomes, metabolomes and physiology. However, despite the importance of leaf formation for our major crops, early developmental processes for rice have not been comprehensively described. Here we detail the temporal developmental trajectory of early rice leaf development and connect morphological changes to metabolism. In particular, a developmental index based on the patterning of epidermal differentiation visualised by electron microscopy enabled high resolution staging of early growth for single primordium metabolite profiling. These data demonstrate that a switch in the constellation of tricarboxylic acid (TCA) cycle metabolites defines a narrow window towards the end of the P3 stage of leaf development. Taken in the context of other data in the literature, our results substantiate that this phase of rice leaf growth, equivalent to a change of primordium length from around 5 to 7.5 mm, defines a major shift in rice leaf determination towards a photosynthetically defined structure. We speculate that efforts to engineer rice leaf structure should focus on the developmental window prior to these determining events.

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Morphological differences in a population of Rufous-collared Sparrow (Zonotrichia capensis, Statius Müller, 1776) (Passerine, Emberizidae) at different elevations in the Tropical Andes

Biota Neotropica ◽

10.1590/1676-0611-bn-2019-0867 ◽

2020 ◽

Vol 20 (2) ◽

Cited By ~ 1

Author(s):

Ana Busi ◽

Leydy J. Cardona-Salazar ◽

Daniela Gómez Castillo ◽

Paula A. Ossa-López ◽

Fredy A. Rivera-Páez ◽

...

Keyword(s):

Environmental Conditions ◽

Morphological Changes ◽

Tail Length ◽

High Elevation ◽

Molecular Techniques ◽

Western Slope ◽

Tropical Andes ◽

Elevation Gradients ◽

Wind Speeds ◽

Zonotrichia Capensis

Abstract Populations that breed along steep elevation gradients show diverse physiological and morphological changes in response to the different environmental conditions. The latter has been discussed by Bergmann’s and Allen’s ecogeographic rules about body and appendage sizes and environmental temperature. We compared morphometric measures (mass, bill width, tarsus, wing, and tail length) of a Zonotrichia capensis population in two localities at different elevations with similar latitudes and photoperiods on the western slope of the Colombian Central Andes. We compared a Low Elevation locality (LE) at 1800 m a.s.l. and a High Elevation locality (HE) at 3853 m a.s.l. that have approximate wind speeds of 1.3 m/s and 8.4 m/s, respectively. During 12 months of sampling, we captured 46 adults using mist-nets; 26 in the LE and 20 in the HE. Each individual was sexed using molecular techniques at the Laboratory of Genetics of the Department of Biological Sciences of Universidad de Caldas. Individuals (males + females) from the HE had longer wings and tails than those from the LE (F1,44 = 5.93; P = 0.019). Also, wings of males in the HE were longer than those of females in both localities and tails of males in the HE were longer than those of LE males. Our results did not agree with what was expected according to Allen’s and Bergmann’s ecogeographic rules. Longer wings and tails increase sustainment, maneuverability, and balance in low atmospheric pressures and strong air currents and these conditions are found at high elevation habitats. Most likely, the longer wings found for HE males allow greater movement during territorial behavior. Further, these differences in morphological traits along elevational gradients could result from micro-evolutionary changes between localities or phenotypic plasticity of individuals exposed to different environmental conditions.

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Signal Integration in Plant Abiotic Stress Responses via Multistep Phosphorelay Signaling

Frontiers in Plant Science ◽

10.3389/fpls.2021.644823 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jan Skalak ◽

Katrina Leslie Nicolas ◽

Radomira Vankova ◽

Jan Hejatko

Keyword(s):

Abiotic Stress ◽

Stress Responses ◽

Environmental Conditions ◽

Molecular Mechanisms ◽

Geographical Location ◽

Survival Strategies ◽

Balance Growth ◽

Adaptive Responses ◽

Wide Range ◽

Sensor Kinases

Plants growing in any particular geographical location are exposed to variable and diverse environmental conditions throughout their lifespan. The multifactorial environmental pressure resulted into evolution of plant adaptation and survival strategies requiring ability to integrate multiple signals that combine to yield specific responses. These adaptive responses enable plants to maintain their growth and development while acquiring tolerance to a variety of environmental conditions. An essential signaling cascade that incorporates a wide range of exogenous as well as endogenous stimuli is multistep phosphorelay (MSP). MSP mediates the signaling of essential plant hormones that balance growth, development, and environmental adaptation. Nevertheless, the mechanisms by which specific signals are recognized by a commonly-occurring pathway are not yet clearly understood. Here we summarize our knowledge on the latest model of multistep phosphorelay signaling in plants and the molecular mechanisms underlying the integration of multiple inputs including both hormonal (cytokinins, ethylene and abscisic acid) and environmental (light and temperature) signals into a common pathway. We provide an overview of abiotic stress responses mediated via MSP signaling that are both hormone-dependent and independent. We highlight the mutual interactions of key players such as sensor kinases of various substrate specificities including their downstream targets. These constitute a tightly interconnected signaling network, enabling timely adaptation by the plant to an ever-changing environment. Finally, we propose possible future directions in stress-oriented research on MSP signaling and highlight its potential importance for targeted crop breeding.

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Exogenous GLP-1 Stimulates TCA Cycle and Suppresses Gluconeogenesis and Ketogenesis in Late-fasted Northern Elephant Seals Pups

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00211.2020 ◽

2021 ◽

Author(s):

Jaapna Dhillon ◽

Jose A Viscarra ◽

John W. Newman ◽

Oliver Fiehn ◽

Daniel E. Crocker ◽

...

Keyword(s):

Tca Cycle ◽

Elephant Seal ◽

Northern Elephant Seal ◽

Fasting Period ◽

Mediated Effects ◽

Plasma Metabolome ◽

Northern Elephant Seals ◽

Metabolite Profiles ◽

Glucagon Like Peptide ◽

Glucagon Like Peptide 1

The post-weaning fast of northern elephant seal pups is characterized by a lipid-dependent metabolism and associated with a decrease in plasma glucagon-like peptide-1 (GLP-1), insulin, and glucose and increased gluconeogenesis (GNG) and ketogenesis. We have also demonstrated that exogenous GLP-1 infusion increased plasma insulin despite simultaneous increases in cortisol and glucagon, which collectively present contradictory regulatory stimuli of GNG, ketogenesis, and glycolysis. To assess the effects of GLP-1 on metabolism using primary carbon metabolite profiles in late-fasted seal pups, we dose-dependently infused late-fasted seals with low (LDG; 10 pM/kg; n=3) or high (HDG; 100 pM/kg; n=4) GLP-1 immediately following a glucose bolus (0.5g/kg), using glucose without GLP-1 as control (n=5). Infusions were performed in similarly aged animals 6-8 weeks into their post-weaning fast. The plasma metabolome was measured from samples collected at 5 time points just prior to and during the infusions, and network maps constructed to robustly evaluate the effects of GLP-1 on primary carbon metabolism. HDG increased key tricarboxylic acid (TCA) cycle metabolites, and decreased phosphoenolpyruvate and acetoacetate (P<0.05) suggesting that elevated levels of GLP-1 promote glycolysis and suppress GNG and ketogenesis, which collectively increase glucose clearance. These GLP-1-mediated effects on cellular metabolism help to explain why plasma GLP-1 concentrations decrease naturally in fasting pups as an evolved mechanism to help conserve glucose during the late-fasting period.

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Final Note of Special Issue “Tardigrades Taxonomy, Biology and Ecology”

Diversity ◽

10.3390/d12050169 ◽

2020 ◽

Vol 12 (5) ◽

pp. 169

Author(s):

Łukasz Kaczmarek

Keyword(s):

Broad Spectrum ◽

Environmental Conditions ◽

Polar Regions ◽

Special Issue ◽

Community Structures ◽

Interpopulation Variability ◽

Final Note ◽

Terrestrial Habitats ◽

Almost All ◽

Water Bears

Tardigrada (water bears) are microscopic invertebrates inhabiting aquatic (freshwater and marine) and terrestrial habitats. They are thriving in almost all Earth ecosystems from deepest oceans to highest mountains, from tropics to polar regions. Water bears are probably most famous for their cryptobiotic abilities, which allow them to survive a broad spectrum of extreme environmental conditions. The Special Issue on tardigrades was launched to popularize research on these fascinating microinvertebrates. The published papers were focused on (a) marine and terrestrial tardigrades diversity, (b) interpopulation variability of Antarctic eutardigrade Paramacrobiotus fairbanksi, (c) encystment in freshwater eutardigrade Thulinius ruffoi and (d) use of a metabarcoding approach to community structures studies in microenvironments.

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Ultrastructure of Stigonema in the Cephalodia of Stereocaulon Paschale

The Lichenologist ◽

10.1017/s0024282983000274 ◽

1983 ◽

Vol 15 (2) ◽

pp. 181-190 ◽

Cited By ~ 4

Author(s):

Birgitta Bergman ◽

Kerstin Huss-Danell

Keyword(s):

Seasonal Variation ◽

Metabolic Activity ◽

Lipid Droplets ◽

Nitrogenase Activity ◽

Late Winter ◽

Nitrogen Storage ◽

Bare Ground ◽

Carbon And Nitrogen ◽

Dividing Cells ◽

Storage Products

AbstractSince seasonal variation in the nitrogenase activity of Stereocaulon paschale is known, the infrastructure of Stigonema in the cephalodia was examined in thalli of S. paschale collected from under snow in late winter, and from bare ground in late autumn. In contrast to the Stigonema cells of the autumn material, those of the winter material were relatively devoid of osmiophilic (lipid) droplets and polyglucoside and cyanophycin granules, reflecting that carbon and nitrogen storage products had been metabolized. In young cephalodia dividing cells were common, while in old cephalodia degenerating cells predominated. Haustoria appeared in material collected in both seasons, but may be limited to degenerating Stigonema cells or to Stigonema cells with a low metabolic activity.

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Notes on the evolution of the ammonite families Aulacostephanidae and Cardioceratidae and the stratigraphy of the uppermost Oxfordian and lowermost Kimmeridgian in the Staffin Bay sections (Isle of Skye, Northern Scotland)

Volumina Jurassica ◽

10.5604/01.3001.0012.2437 ◽

2018 ◽

Vol XV (1) ◽

pp. 27-50 ◽

Cited By ~ 2

Author(s):

Andrzej WIERZBOWSKI ◽

Bronisław A. MATYJA ◽

John WRIGHT

Keyword(s):

Environmental Conditions ◽

Morphological Changes ◽

Slight Modification ◽

Individual Development ◽

Phylogenetic Constraints ◽

Isle Of Skye

Detailed study of all the ammonite collections gathered by the authors in the Staffin Bay sections has resulted in minor changes in the distribution of ammonite taxa, and slight modification of the position of the Oxfordian/Kimmeridgian boundary. Most significant is the discovery of Pictonia (Triozites) cf. seminudata which results in the placing of the stage boundary 0.16 m below the level formerly proposed. This study discusses the evolution of the Subboreal family Aulacostephanidae, and the Boreal family Cardioceratidae, indicating changes in the patterns of individual development in the evolution of both families in terms of heterochrony. The Oxfordian/ Kimmeridgian boundary interval shows major morphological changes in both ammonite families which were released from phylogenetic constraints by heterochrony, closely related to changes in environmental conditions.

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