Solubility Isotherms of Gypsum, Hemihydrate, and Anhydrite in the Ternary Systems CaSO₄ + MSO₄ + H₂O (M = Mn, Co, Ni, Cu, Zn) at <i>T</i> = 298.1 K to 373.1 K

The solubilities of anhydrite in the ternary systems CaSO₄ + MSO₄ + H₂O (M = Co, Ni) were determined through isothermal solution saturation at 348.1 K and 363.1 K. At low bivalent metal sulfate concentrations, anhydrite solubility decreases until it eventually reaches a minimum. Anhydrite solubility subsequently increases with the amount of heavy metal sulfate to a maximum. At this point, further increases in the concentration of metal sulfate decreases the solubility of anhydrite until saturation of the added bivalent metal sulfate. A Pitzer thermodynamic model was selected to predict isopiestic data including calcium sulfate solubilities of the ternary systems CaSO₄ + MSO₄ + H₂O (M = Mn, Co, Ni, Cu, Zn) from 298.1 K to 373.1 K. The functional dependencies of the MSO₄ (M = Ni, Cu, Zn) ion interaction parameters with temperature were determined, and the third virial parameters were given. The calculated solubilities are in agreement with the available experimental data. Using the Pitzer model and parameters, the solubility isotherms of metastable solid-phase hemihydrate, as well as gypsum and anhydrite, in the CaSO₄ + MSO₄ + H₂O (M = Mn, Co, Ni, Cu, Zn) systems were predicted over a wide range of temperatures and concentrations

Heat map of significantly different expression genes encoding heat shock proteins (Hsps) under high temperature stress.

Red: upregulation; Green: downregulation.</p

DataSheet_1_Calcium-Calmodulin-Involved Heat Shock Response of Neoporphyra haitanensis.pdf

Increasing global temperatures have seriously affected the sustainable development of Neoporphyra haitanensis cultivation. Although several pathways are reported to be involved in the response of N. haitanensis to heat stress, it is unknown which ones are activated by signal transduction. Previously, we detected a large influx of calcium ions (Ca2+) in N. haitanensis under heat stress. In this study, we further investigated the specificity of Ca2+ signaling and how is it transduced. Transmission electron microscopy and Fv/Fm analyses showed that the Ca2+ signal derived from extracellular Ca2+ formed at the early stage of the response to heat stress, and the signal was recognized and decoded by N. haitanensis calmodulin (NhCaM). In yeast two-hybrid assays, DnaJ, a voltage-dependent anion channel, and a bromodomain-containing protein interacted with PhCaM1 in vivo. The transcript levels of the genes encoding these proteins increased significantly in response to heat stress, but decreased upon inhibition of NhCaM1, indicating that these interacting factors were positively related to NhCaM1. Additionally, a comparative transcriptome analysis indicated that Ca2+ signal transduction is involved in phosphatidylinositol, photosystem processes, and energy metabolism in N. haitanensis under heat stress. Our results suggest that Ca2+-CaM plays important roles in signal transduction in response to heat stress in N. haitanensis.</p

Image_1_The mechanism of maintaining intracellular homeostasis in the red alga Pyropia haitanensis under hyposaline stress.tif

The cultivation of hyposaline-tolerant varieties of the red alga Pyropia haitanensis is not only conducive to expanding the area of intertidal seaweed cultivation, but also contributes to preventing eutrophication of coastal waters. Research on the mechanism of hyposaline tolerance of P. haitanensis is an important prerequisite for breeding hyposaline-tolerant varieties. Here, we used proteomics and targeted metabolomics technologies to identify the key proteins and metabolites in thalli of P. haitanensis that changed under two hyposaline stress treatments: 0‰, LSS 0; 5‰, LSS 5. Responses of thalli of P. haitanensis to hyposaline stress included to inhibit protein synthesis, recruit molecular chaperones, and enhance the removal of misfolded proteins to maintain the dynamic balance of protein folding and removal; the response was similar under hypersaline stress. Glycolysis was the main energy supply pathway, and thalli actively maintained the stability of the cell membrane under hyposaline stress, which was distinct from the response to hypersaline stress. Compared with the LSS 0 treatment, P. haitanensis exhibited a more adequate energy supply, more stable endoplasmic reticulum environment and more intact membrane system under the LSS 5 treatment. The results improve understanding of the hyposaline tolerance mechanism of intertidal seaweed and provide a theoretical basis for the development of hyposaline-tolerant varieties.</p

Image_2_The mechanism of maintaining intracellular homeostasis in the red alga Pyropia haitanensis under hyposaline stress.tif

The cultivation of hyposaline-tolerant varieties of the red alga Pyropia haitanensis is not only conducive to expanding the area of intertidal seaweed cultivation, but also contributes to preventing eutrophication of coastal waters. Research on the mechanism of hyposaline tolerance of P. haitanensis is an important prerequisite for breeding hyposaline-tolerant varieties. Here, we used proteomics and targeted metabolomics technologies to identify the key proteins and metabolites in thalli of P. haitanensis that changed under two hyposaline stress treatments: 0‰, LSS 0; 5‰, LSS 5. Responses of thalli of P. haitanensis to hyposaline stress included to inhibit protein synthesis, recruit molecular chaperones, and enhance the removal of misfolded proteins to maintain the dynamic balance of protein folding and removal; the response was similar under hypersaline stress. Glycolysis was the main energy supply pathway, and thalli actively maintained the stability of the cell membrane under hyposaline stress, which was distinct from the response to hypersaline stress. Compared with the LSS 0 treatment, P. haitanensis exhibited a more adequate energy supply, more stable endoplasmic reticulum environment and more intact membrane system under the LSS 5 treatment. The results improve understanding of the hyposaline tolerance mechanism of intertidal seaweed and provide a theoretical basis for the development of hyposaline-tolerant varieties.</p

Transcriptomic study to understand thermal adaptation in a high temperature-tolerant strain of <i>Pyropia haitanensis</i>

<div><p><i>Pyropia haitanensis</i>, a high-yield commercial seaweed in China, is currently undergoing increasing levels of high-temperature stress due to gradual global warming. The mechanisms of plant responses to high temperature stress vary with not only plant type but also the degree and duration of high temperature. To understand the mechanism underlying thermal tolerance in <i>P</i>. <i>haitanensis</i>, gene expression and regulation in response to short- and long-term temperature stresses (SHS and LHS) was investigated by performing genome-wide high-throughput transcriptomic sequencing for a high temperature tolerant strain (HTT). A total of 14,164 differential expression genes were identified to be high temperature-responsive in at least one time point by high-temperature treatment, representing 41.10% of the total number of unigenes. The present data indicated a decrease in the photosynthetic and energy metabolic rates in HTT to reduce unnecessary energy consumption, which in turn facilitated in the rapid establishment of acclimatory homeostasis in its transcriptome during SHS. On the other hand, an increase in energy consumption and antioxidant substance activity was observed with LHS, which apparently facilitates in the development of resistance against severe oxidative stress. Meanwhile, ubiquitin-mediated proteolysis, brassinosteroids, and heat shock proteins also play a vital role in HTT. The effects of SHS and LHS on the mechanism of HTT to resist heat stress were relatively different. The findings may facilitate further studies on gene discovery and the molecular mechanisms underlying high-temperature tolerance in <i>P</i>. <i>haitanensis</i>, as well as allow improvement of breeding schemes for high temperature-tolerant macroalgae that can resist global warming.</p></div

Table_1_The mechanism of maintaining intracellular homeostasis in the red alga Pyropia haitanensis under hyposaline stress.xls

The cultivation of hyposaline-tolerant varieties of the red alga Pyropia haitanensis is not only conducive to expanding the area of intertidal seaweed cultivation, but also contributes to preventing eutrophication of coastal waters. Research on the mechanism of hyposaline tolerance of P. haitanensis is an important prerequisite for breeding hyposaline-tolerant varieties. Here, we used proteomics and targeted metabolomics technologies to identify the key proteins and metabolites in thalli of P. haitanensis that changed under two hyposaline stress treatments: 0‰, LSS 0; 5‰, LSS 5. Responses of thalli of P. haitanensis to hyposaline stress included to inhibit protein synthesis, recruit molecular chaperones, and enhance the removal of misfolded proteins to maintain the dynamic balance of protein folding and removal; the response was similar under hypersaline stress. Glycolysis was the main energy supply pathway, and thalli actively maintained the stability of the cell membrane under hyposaline stress, which was distinct from the response to hypersaline stress. Compared with the LSS 0 treatment, P. haitanensis exhibited a more adequate energy supply, more stable endoplasmic reticulum environment and more intact membrane system under the LSS 5 treatment. The results improve understanding of the hyposaline tolerance mechanism of intertidal seaweed and provide a theoretical basis for the development of hyposaline-tolerant varieties.</p

Image_1_Effect of hyposaline stress on the release of dissolved organic carbon from five common macroalgal species.tif

Macroalgae are important primary producers in coastal waters; they have high carbon sink potential and are often subjected to hyposaline stress in their natural habitats. The effect of hyposaline stress on dissolved organic carbon (DOC) release from macroalgae remains to be studied in depth. In this study, five common intertidal macroalgae in coastal waters of Fujian Province, China—Pyropia haitaneisis, Gracilaria lemaneiformis, Sargassum thunbergii, Enteromorpha prolifera, and Ulva lactuca—were used as research materials to investigate the effects of 6-h hyposaline treatments (5 PSU, 0 PSU) on the growth, DOC release rate, photosynthesis, respiration, and contents of carbon (C), nitrogen (N), and phosphorus (P). Our results showed that, although there were significant interspecific differences in the tolerance of the five species of macroalgae to low salinity, the DOC release rate of macroalgae increased overall with decreasing salinity, while the photosynthetic rate showed the opposite trend. Hyposaline treatments reduced the net photosynthetic rate of macroalgae, as the net photosynthetic rate of all five species decreased by more than 50% and 75% under the 5 PSU and 0 PSU treatments, respectively. The tissue C contents of P. haitaneisis, G. lemaneiformis, and E. prolifera increased significantly with decreasing salinity, by 6.90%, 40.15%, and 43.80% at 0 PSU, respectively. However, the tissue C contents of S. thunbergii and U. lactuca were not influenced or were slightly decreased by low salinity. These results suggest that short-term hyposaline treatment has a dual effect on organic carbon accumulation of macroalgae by inhibiting photosynthetic carbon fixation and increasing DOC release, and this in turn may have a large impact on the carbon cycle in macroalgae enrichment areas.</p

Image_4_The mechanism of maintaining intracellular homeostasis in the red alga Pyropia haitanensis under hyposaline stress.tif

The cultivation of hyposaline-tolerant varieties of the red alga Pyropia haitanensis is not only conducive to expanding the area of intertidal seaweed cultivation, but also contributes to preventing eutrophication of coastal waters. Research on the mechanism of hyposaline tolerance of P. haitanensis is an important prerequisite for breeding hyposaline-tolerant varieties. Here, we used proteomics and targeted metabolomics technologies to identify the key proteins and metabolites in thalli of P. haitanensis that changed under two hyposaline stress treatments: 0‰, LSS 0; 5‰, LSS 5. Responses of thalli of P. haitanensis to hyposaline stress included to inhibit protein synthesis, recruit molecular chaperones, and enhance the removal of misfolded proteins to maintain the dynamic balance of protein folding and removal; the response was similar under hypersaline stress. Glycolysis was the main energy supply pathway, and thalli actively maintained the stability of the cell membrane under hyposaline stress, which was distinct from the response to hypersaline stress. Compared with the LSS 0 treatment, P. haitanensis exhibited a more adequate energy supply, more stable endoplasmic reticulum environment and more intact membrane system under the LSS 5 treatment. The results improve understanding of the hyposaline tolerance mechanism of intertidal seaweed and provide a theoretical basis for the development of hyposaline-tolerant varieties.</p

Image_5_The mechanism of maintaining intracellular homeostasis in the red alga Pyropia haitanensis under hyposaline stress.tif

The cultivation of hyposaline-tolerant varieties of the red alga Pyropia haitanensis is not only conducive to expanding the area of intertidal seaweed cultivation, but also contributes to preventing eutrophication of coastal waters. Research on the mechanism of hyposaline tolerance of P. haitanensis is an important prerequisite for breeding hyposaline-tolerant varieties. Here, we used proteomics and targeted metabolomics technologies to identify the key proteins and metabolites in thalli of P. haitanensis that changed under two hyposaline stress treatments: 0‰, LSS 0; 5‰, LSS 5. Responses of thalli of P. haitanensis to hyposaline stress included to inhibit protein synthesis, recruit molecular chaperones, and enhance the removal of misfolded proteins to maintain the dynamic balance of protein folding and removal; the response was similar under hypersaline stress. Glycolysis was the main energy supply pathway, and thalli actively maintained the stability of the cell membrane under hyposaline stress, which was distinct from the response to hypersaline stress. Compared with the LSS 0 treatment, P. haitanensis exhibited a more adequate energy supply, more stable endoplasmic reticulum environment and more intact membrane system under the LSS 5 treatment. The results improve understanding of the hyposaline tolerance mechanism of intertidal seaweed and provide a theoretical basis for the development of hyposaline-tolerant varieties.</p