scholarly journals Stress Reshapes the Physiological Response of Halophile Fungi to Salinity

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 525 ◽  
Author(s):  
Yordanis Pérez-Llano ◽  
Eya Caridad Rodríguez-Pupo ◽  
Irina S. Druzhinina ◽  
Komal Chenthamara ◽  
Feng Cai ◽  
...  
Keyword(s):  
Cell Wall ◽  
Compatible Solutes ◽  
Saline Stress ◽  
Physiological Mechanisms ◽  
Main Compound ◽  
Beta Glucans ◽  
Extreme Salinity ◽  
Transcriptomic Changes ◽  
Halophilic Species ◽  
Basidiomycete Fungi

(1) Background: Mechanisms of cellular and molecular adaptation of fungi to salinity have been commonly drawn from halotolerant strains and few studies in basidiomycete fungi. These studies have been conducted in settings where cells are subjected to stress, either hypo- or hyperosmotic, which can be a confounding factor in describing physiological mechanisms related to salinity. (2) Methods: We have studied transcriptomic changes in Aspergillus sydowii, a halophilic species, when growing in three different salinity conditions (No NaCl, 0.5 M, and 2.0 M NaCl). (3) Results: In this fungus, major physiological modifications occur under high salinity (2.0 M NaCl) and not when cultured under optimal conditions (0.5 M NaCl), suggesting that most of the mechanisms described for halophilic growth are a consequence of saline stress response and not an adaptation to saline conditions. Cell wall modifications occur exclusively at extreme salinity, with an increase in cell wall thickness and lamellar structure, which seem to involve a decrease in chitin content and an augmented content of alfa and beta-glucans. Additionally, three hydrophobin genes were differentially expressed under hypo- or hyperosmotic stress but not when the fungus grows optimally. Regarding compatible solutes, glycerol is the main compound accumulated in salt stress conditions, whereas trehalose is accumulated in the absence of salt. (4) Conclusions: Physiological responses to salinity vary greatly between optimal and high salt concentrations and are not a simple graded effect as the salt concentration increases. Our results highlight the influence of stress in reshaping the response of extremophiles to environmental challenges.

Cell‐Wall Beta‐Glucans of Saccharomyces cerevisiae

2002 ◽  
Author(s):  
Gerrit J. P. Dijkgraaf ◽  
Huijuan Li ◽  
Howard Bussey
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Wall ◽  
Beta Glucans

Elucidating the role of polygalacturonase genes in strawberry fruit softening

2020 ◽  
Vol 71 (22) ◽  
pp. 7103-7117
Author(s):  
Candelas Paniagua ◽  
Pablo Ric-Varas ◽  
Juan A García-Gago ◽  
Gloria López-Casado ◽  
Rosario Blanco-Portales ◽  
...  
Keyword(s):  
Cell Wall ◽  
Wild Type ◽  
Additional Increase ◽  
Rhamnogalacturonan I ◽  
Transgene Stacking ◽  
Genes Encoding ◽  
Cell Turgor ◽  
Transcriptomic Level ◽  
Transcriptomic Changes

Abstract To disentangle the role of polygalacturonase (PG) genes in strawberry softening, the two PG genes most expressed in ripe receptacles, FaPG1 and FaPG2, were down-regulated. Transgenic ripe fruits were firmer than those of the wild type when PG genes were silenced individually. Simultaneous silencing of both PG genes by transgene stacking did not result in an additional increase in firmness. Cell walls from ripe fruits were characterized by a carbohydrate microarray. Higher signals of homogalacturonan and rhamnogalacturonan I pectin epitopes in polysaccharide fractions tightly bound to the cell wall were observed in the transgenic genotypes, suggesting a lower pectin solubilization. At the transcriptomic level, the suppression of FaPG1 or FaPG2 alone induced few transcriptomic changes in the ripe receptacle, but the amount of differentially expressed genes increased notably when both genes were silenced. Many genes encoding cell wall-modifying enzymes were down-regulated. The expression of a putative high affinity potassium transporter was induced in all transgenic genotypes, indicating that cell wall weakening and loss of cell turgor could be linked. These results suggest that, besides the disassembly of pectins tightly linked to the cell wall, PGs could play other roles in strawberry softening, such as the release of oligogalacturonides exerting a positive feedback in softening.

Osmoregulation by Organisms Exposed to Saline Stress: Physiological Mechanisms and Genetic Manipulation

1982 ◽  
pp. 283-302 ◽  
Author(s):  
D. W. Rains ◽  
L. Csonka ◽  
D. Le Rudulier ◽  
T. P. Croughan ◽  
S. S. Yang ◽  
...  
Keyword(s):  
Genetic Manipulation ◽  
Saline Stress ◽  
Physiological Mechanisms

scholarly journals Post-diapause transcriptomic restarts: insight from a high-latitude copepod

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Vittoria Roncalli ◽  
Matthew C. Cieslak ◽  
Ann M. Castelfranco ◽  
Russell R. Hopcroft ◽  
Daniel K. Hartline ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Transcriptional Profiling ◽  
Tca Cycle ◽  
Physiological Mechanisms ◽  
Timing Of Reproduction ◽  
The Tca Cycle ◽  
Rapid Changes ◽  
Transcriptional Changes ◽  
Division Cell ◽  
Transcriptomic Changes

Abstract Background Diapause is a seasonal dormancy that allows organisms to survive unfavorable conditions and optimizes the timing of reproduction and growth. Emergence from diapause reverses the state of arrested development and metabolic suppression returning the organism to an active state. The physiological mechanisms that regulate the transition from diapause to post-diapause are still unknown. In this study, this transition has been characterized for the sub-arctic calanoid copepod Neocalanus flemingeri, a key crustacean zooplankter that supports the highly productive North Pacific fisheries. Transcriptional profiling of females, determined over a two-week time series starting with diapausing females collected from > 400 m depth, characterized the molecular mechanisms that regulate the post-diapause trajectory. Results A complex set of transitions in relative gene expression defined the transcriptomic changes from diapause to post-diapause. Despite low temperatures (5–6 °C), the switch from a “diapause” to a “post-diapause” transcriptional profile occurred within 12 h of the termination stimulus. Transcriptional changes signaling the end of diapause were activated within one-hour post collection and included the up-regulation of genes involved in the 20E cascade pathway, the TCA cycle and RNA metabolism in combination with the down-regulation of genes associated with chromatin silencing. By 12 h, females exhibited a post-diapause phenotype characterized by the up-regulation of genes involved in cell division, cell differentiation and multiple developmental processes. By seven days post collection, the reproductive program was fully activated as indicated by up-regulation of genes involved in oogenesis and energy metabolism, processes that were enriched among the differentially expressed genes. Conclusions The analysis revealed a finely structured, precisely orchestrated sequence of transcriptional changes that led to rapid changes in the activation of biological processes paving the way to the successful completion of the reproductive program. Our findings lead to new hypotheses related to potentially universal mechanisms that terminate diapause before an organism can resume its developmental program.

scholarly journals Micafungin-induced Cell Wall Damage Stimulates Microcycle Conidiation in Aspergillus nidulans

2021 ◽  
Author(s):  
Samantha Reese ◽  
Cynthia Chelius ◽  
Wayne R Riekhof ◽  
Mark R Marten ◽  
Steven D Harris
Keyword(s):  
Cell Wall ◽  
Aspergillus Nidulans ◽  
Hyphal Growth ◽  
Dependent Manner ◽  
Fungal Cell ◽  
Cell Wall Damage ◽  
Morphological Studies ◽  
Beta Glucans ◽  
General Response ◽  
Microcycle Conidiation

Fungal cell wall receptors relay messages about the state of the cell wall to the nucleus through the Cell Wall Integrity Signaling (CWIS) pathway. The ultimate role of the CWIS pathway is to coordinate repair of cell wall damage and to restore normal hyphal growth. Echinocandins such as micafungin represent a class of antifungals that trigger cell wall damage by affecting synthesis of beta-glucans, filamentous fungal response to these antifungals are fundamentally unknown. To obtain a better understanding of the dynamics of the CWIS response and its multiple effects, we have coupled dynamic transcriptome analysis with morphological studies of Aspergillus nidulans hyphae responding to micafungin. Our results reveal that expression of the master regulator of asexual development, BrlA, is induced by micafungin exposure. Further study showed that micafungin elicits microcycle conidiation in a BrlA-dependent manner, and that this response is abolished in the absence of MpkA. Our results suggest that microcycle conidiation may be a general response to cell wall perturbation which in some cases would enable fungi to tolerate or survive otherwise lethal damage.

Effects of Bread Yeast Cell Wall Beta-Glucans on Mice with Loperamide-Induced Constipation

2019 ◽  
Vol 22 (10) ◽  
pp. 1009-1021 ◽  
Author(s):  
Zhuoyi Chen ◽  
SuSu Lin ◽  
Yu Jiang ◽  
Ling Liu ◽  
Jinyan Jiang ◽  
...  
Keyword(s):  
Cell Wall ◽  
Yeast Cell ◽  
Yeast Cell Wall ◽  
Beta Glucans

scholarly journals On the carbohydrate composition and nutritive value of some cereals

1970 ◽  
Vol 42 (1) ◽  
pp. 21-29 ◽  
Author(s):  
Maija-Liisa Salo ◽  
Kaija Kotilainen
Keyword(s):  
Cell Wall ◽  
Crude Protein ◽  
Nutritive Value ◽  
Starch Content ◽  
Crude Fibre ◽  
Main Compound ◽  
Main Components ◽  
Fibre Analysis ◽  
Hydrolysis Of

The contents and the distribution between the different grain parts of starch, hemicellulose, cellulose, crude lignin, crude protein and ash have been determined for oat, barley, rye and two wheat species. The relative proportions of the different structural units of the hemicellulose have also been determined. Furthermore, a method is proposed for the determination of the cell-wall complex in cereals. Oat and barley differ from wheat and rye to an appreciable extent only in respect of the hull. The hulls consist of strawlike material rich in lignin, cellulose and xylan; they are richer in xylan than the straw proper. The fruit and seed coat enveloping the seed (viz. the bran) contains relatively small amounts of lignin and cellulose. The bran is chiefly composed of hemicellulose with xylose and arabinose as the main components. The main compound of the endosperm is starch, although some hemicellulose and protein are present, whereas only minor amounts of cellulose and lignin can be found. In the samples investigated only small differences were noted between the compositions of wheat, rye, dehulled oat and dehulled barley; wheat had the highest starch content, rye the highest hemicellulose content, and oat the highest contents of crude protein and lignin. The cell-wall complex determined as the residue after enzymatic hydrolysis of the starch agreed well with that obtained by fractionation. On the other hand, the detergent-fibre values differed from the fractionation results considerably, and the conventional crude fibre analysis yielded results which were about 1.5 times that of cellulose. The feed-values of the different grain parts are discussed on the basis of the analysis results obtained.

scholarly journals Examining the Osmotic Response of Acidihalobacter aeolianus after Exposure to Salt Stress

2021 ◽  
Vol 10 (1) ◽  
pp. 22
Author(s):  
Melissa K. Corbett ◽  
Liam Anstiss ◽  
April Gifford ◽  
Ross M. Graham ◽  
Elizabeth L. J. Watkin
Keyword(s):  
Osmotic Stress ◽  
Compatible Solutes ◽  
Organic Osmolytes ◽  
Osmotic Response ◽  
Environmental Instability ◽  
Acidic Environments ◽  
High Concentrations ◽  
Cellular Stresses ◽  
The Impact ◽  
Halophilic Species

Acidihalobacter aeolianus is an acidophilic, halo-tolerant organism isolated from a marine environment near a hydrothermal vent, an ecosystem whereby levels of salinity and total dissolved salts are constantly fluctuating creating ongoing cellular stresses. In order to survive these continuing changes, the synthesis of compatible solutes—also known as organic osmolytes—is suspected to occur, aiding in minimising the overall impact of environmental instability. Previous studies on A. aeolianus identified genes necessary for the accumulation of proline, betaine and ectoine, which are known to act as compatible solutes in other halophilic species. In this study, the impact of increasing the osmotic stress as well as the toxic ion effect was investigated by subjecting A. aeolianus to concentrations of NaCl and MgSO4 up to 1.27 M. Exposure to high concentrations of Cl- resulted in the increase of ectC expression in log-phase cells with a corresponding accumulation of ectoine at stationary phase. Osmotic stress via MgSO4 exposure did not trigger the same up-regulation of ectC or accumulation of ectoine, indicating the transcriptionally regulated response against osmotic stress was induced by chloride toxicity. These findings have highlighted how the adaptive properties of halo-tolerant organisms in acidic environments are likely to differ and are dependent on the initial stressor.

Histochemical analysis of the root epidermal mucilage in maize and wheat

2004 ◽  
Vol 82 (10) ◽  
pp. 1419-1428
Author(s):  
Pedro HPA Schildknecht ◽  
Marília de M Castro ◽  
Benedicto C Vidal
Keyword(s):  
Cell Wall ◽  
Triticum Aestivum L ◽  
Root Surface ◽  
Histochemical Analysis ◽  
Lipophilic Compounds ◽  
Main Compound ◽  
Root Mucilage ◽  
Soil Interface ◽  
Crystalline Array ◽  
Important Structure

The root epidermal mucilage is an important structure at the root–soil interface, but its composition is not fully understood. In contrast to the root cap mucilage, the epidermal mucilage layer is firmly attached to the cell walls and cannot be collected easily in water. In this work, we examined histochemically the compounds present in the epidermal mucilage of Zea mays L. and Triticum aestivum L., as well as its anisotropic characteristics. Birefringence analysis showed a highly crystalline array of microfibrils arranged parallel to the root surface. Tests for lignin, lipophilic compounds, pectin, callose, and cellulose detected only the two latter compounds. Callose occurred sporadically as interrupted deposits in the epidermal mucilage and was detected in only a few plants. Cellulose was the main compound of this layer. We speculate that the epidermal mucilage is synthesized by the root epidermal cells and is firmly anchored to the wall at so many points as to give the appearance of being part of the cell wall. The cellulose present in the outer surface of the roots may act as a filtering mesh and a barrier to the external environment. The epidermal mucilage may also be involved in protection against physical, biological, and chemical agents.Key words: cell wall, root mucilage, cellulose, rhizosphere, maize.

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