scholarly journals Bioactive Cembranoid Composition in the Soft Coral of Sarcophyton glaccum on The Response to Changing pH

2017 ◽  
Vol 22 (1) ◽  
pp. 25
Author(s):  
Hedi Indra Januar ◽  
Neviaty Putri Zamani ◽  
Dedi Soedharma ◽  
Ekowati Chasanah

Soft coral is predicted to outcompete with hard coral in future ocean acidification scenarios. Beside the biological resilience shown in acidic conditions, soft corals ability to maintain or compete for space is shown to relate with their ability to produce cytotoxic cembranoid-type compounds. The aim of this study was to investigate composition of cytotoxic cembranoid compounds of Sarcophyton glaccum soft coral exposed to current and predicted future ocean acidification scenarios. Sarcophyton glaccum colonies were acclimated along a pH gradient to simulate predicted increases in ocean acidification: natural/current (pH 8,2), slight increase in acidification (pH 8.0 year-1 2060), and moderate increase in acidification (pH 7,8 year­-1 2100). Cembranoid composition was determined by quantitative Nuclear Magnetic Resonance spectroscopy while cytotoxic activity was determined against tumor cell lines. Results of the study showed cytotoxicity and sarcophytoxide (the most active cembranoid compound in observed Sarcophyton glaccum) were both found to be higher at pH 8,0. However, a further increase of acidification resulted on a reduction of both the cytotoxicity and sarcophytoxide production. This suggests that acidification pressures affect directly the defense system metabolism of Sarcophyton glaccum and that while they may be resilient to small decreases in pH, their ability to compete for space may be hampered by more pronounced changes. Keywords: Cembranoids; Cytotoxic; Sarcophyton glaccum; Seawater Acidification; Soft Coral.

2008 ◽  
Vol 5 (4) ◽  
pp. 1023-1031 ◽  
Author(s):  
X. Mari

Abstract. The absorption of anthropogenic atmospheric carbon dioxide (CO2) by the ocean provokes its acidification. This acidification may alter several oceanic processes, including the export of biogenic carbon from the upper layer of the ocean, hence providing a feedback on rising atmospheric carbon concentrations. The effect of seawater acidification on transparent exopolymeric particles (TEP) driven aggregation and sedimentation processes were investigated by studying the interactions between latex beads and TEP precursors collected in the lagoon of New Caledonia. A suspension of TEP and beads was prepared and the formation of mixed aggregates was monitored as a function of pH under increasing turbulence intensities. The pH was controlled by addition of sulfuric acid. Aggregation and sedimentation processes driven by TEP were drastically reduced when the pH of seawater decreases within the expected limits imposed by increased anthropogenic CO2 emissions. In addition to the diminution of TEP sticking properties, the diminution of seawater pH led to a significant increase of the TEP pool, most likely due to swollen structures. A diminution of seawater pH by 0.2 units or more led to a stop or a reversal of the downward flux of particles. If applicable to oceanic conditions, the sedimentation of marine aggregates may slow down or even stop as the pH decreases, and the vertical flux of organic carbon may reverse. This would enhance both rising atmospheric carbon and ocean acidification.


FACETS ◽  
2017 ◽  
Vol 2 (1) ◽  
pp. 531-544 ◽  
Author(s):  
Lori S.H. Westmoreland ◽  
Jennifer N. Niemuth ◽  
Hanna S. Gracz ◽  
Michael K. Stoskopf

A reliable marker of early coral response to environmental stressors can help guide decision-making to mitigate global coral reef decline by detecting problems before the development of clinically observable disease. We document the accumulation of acrylic acid in two divergent coral taxa, stony small polyp coral ( Acropora sp.) and soft coral ( Lobophytum sp.), in response to deteriorating water quality characterized by moderately increased ammonia (0.25 ppm) and phosphate (0.15 ppm) concentrations and decreased calcium (360 ppm) concentration, using nuclear magnetic resonance spectroscopy (NMR)-based metabolomic techniques. Changes in acrylic acid concentration in polyp tissues free of zooxanthellae suggest that acrylic acid could be a product of animal metabolism and not exclusively a metabolic by-product of the osmolyte dimethylsulfoniopropionate (DMSP) in marine algae or bacteria. Our findings build on previously documented depletions of acrylic acid in wild coral potentially correlated to temperature stress and provide additional insight into approaches to further characterize the nature of the metabolic accumulation of acrylic acid under controlled experimental conditions.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Katharina E. Fabricius ◽  
Craig Neill ◽  
Erik Van Ooijen ◽  
Joy N. Smith ◽  
Bronte Tilbrook

Abstract Coral reefs are highly sensitive to ocean acidification due to rising atmospheric CO2 concentrations. We present 10 years of data (2009–2019) on the long-term trends and sources of variation in the carbon chemistry from two fixed stations in the Australian Great Barrier Reef. Data from the subtropical mid-shelf GBRWIS comprised 3-h instrument records, and those from the tropical coastal NRSYON were monthly seawater samples. Both stations recorded significant variation in seawater CO2 fugacity (fCO2), attributable to seasonal, daytime, temperature and salinity fluctuations. Superimposed over this variation, fCO2 progressively increased by > 2.0 ± 0.3 µatm year−1 at both stations. Seawater temperature and salinity also increased throughout the decade, whereas seawater pH and the saturation state of aragonite declined. The decadal upward fCO2 trend remained significant in temperature- and salinity-normalised data. Indeed, annual fCO2 minima are now higher than estimated fCO2 maxima in the early 1960s, with mean fCO2 now ~ 28% higher than 60 years ago. Our data indicate that carbonate dissolution from the seafloor is currently unable to buffer the Great Barrier Reef against ocean acidification. This is of great concern for the thousands of coral reefs and other diverse marine ecosystems located in this vast continental shelf system.


2007 ◽  
Vol 28 (3) ◽  
pp. 323-336 ◽  
Author(s):  
Michael C. Rudolph ◽  
James L. McManaman ◽  
TzuLip Phang ◽  
Tanya Russell ◽  
Douglas J. Kominsky ◽  
...  

The mammary gland of the lactating mouse synthesizes and secretes milk lipid equivalent to its entire body weight in a single 20-day lactation cycle, making it one of the most active lipid synthetic organs known. We test the hypothesis that multiple control points and potential regulatory mechanisms regulate milk lipid synthesis at the level of gene expression. The mammary transcriptome of 130 genes involved in glucose metabolism was examined at late pregnancy and early lactation, utilizing data obtained from microarray analysis of mammary glands from quadruplicate FVB mice at pregnancy day 17 and lactation day 2. To correlate changes with physiological parameters, the metabolome obtained from magnetic resonance spectroscopy of flash-frozen glands at day 17 of pregnancy was compared with that at day 2 of lactation. A significant increase in carbohydrates (glucose, lactose, sialic acid) and amino acids (alanine, aspartate, arginine, glutamate) with a moderate increase in important osmolytes ( myo-inositol, betaine, choline derivatives) were observed in the lactating gland. In addition, diets containing 8% or 40% lipid were fed from lactation days 5–10 and mammary glands and livers of triplicate FVB mice prepared for microarray analysis. The results show that substantial regulation of lipid synthesis occurs at the level of mRNA expression and that some of the regulation points differ substantially from the liver. They also implicate the transcription factor SREBP-1c in regulation of part of the pathway.


2020 ◽  
Author(s):  
Maria Teresa Guerra ◽  
Carlos Rocha

<p>Organic and inorganic whole system metabolism for two Irish coastal areas were compared to evaluate carbonate system resilience to acidification. The two systems are characterized by contrasting watershed input types and composition. Kinvara Bay is fed by Submarine Groundwater Discharge (SGD) derived from a karstic catchment while Killary Harbour is fed by river discharge draining a siliciclastic catchment. Freshwater sources to sea have distinct Total Alkalinity (TA) and Dissolved Inorganic Carbon (DIC) concentrations, higher and lower than the open ocean, respectively, but both evidence seasonally variable low pH, ranging from 6.20 to 7.50. Retention of TA and DIC was calculated for the two areas using LOICZ methodology. In Kinvara bay, annually averaged retention of DIC was greater than for TA (5 × 10<sup>4</sup> and 1.5 × 10<sup>5</sup> mol d<sup>-1</sup>), suggesting the system is acidifying further. Conversely, Killary Harbour shows negative TA and DIC retention, with DIC:TA <1, suggesting an internal buffer against ocean acidification is operating.</p><p>Net Community Production (NCP) was calculated for both systems using Dissolved Oxygen data. Subsequently, we estimated Net Community Calcification (NCC) from the ratio between TA and DIC. NCP was always positive in Killary Harbour with an average of 318 mmol O<sub>2</sub> m<sup>-2 </sup>d<sup>-1</sup> (equivalent to 89 mol C m<sup>-2</sup> y<sup>-1</sup>). However, Kinvara Bay shows relatively lower positive NCP in spring and summer (average of 46 mmol O<sub>2</sub> m<sup>-2</sup> d<sup>-1</sup>), but negative NCP in autumn and winter. Therefore, Kinvara Bay’s Total Organic Carbon (TOC) production was low, at ~21 g m<sup>-2</sup> y<sup>-1</sup> and not enough to overcome acidification driven by the SGD source composition. These results emphasize the complexity of interactions between the drivers of coastal acidification rate, affecting our ability to accurately assess the resilience of the carbonate system in these areas to ocean acidification pressure in the future.</p>


Author(s):  
Hedi Indra Januar ◽  
Neviaty Putri Zamani ◽  
Dedi Soedharma ◽  
Ekowati Chasanah

Cembranoid content in soft coral is known as a chemotype that relate with genotype and environment. This research aimed to characterize the cembranoid Sarcophyton soft coral from the reef that acidified by CO2 volcanic vents (pHT 7.8) at Volcano Islands waters, Banda-Neira (Indonesia), as a means of predicting the future impact of ocean acidification to the genetic diversity of Sarcophyton soft coral. 30 random colonies were taken, combined, and extracted with ethanol. Cembranoid isolation and identification had been done by high performance liquid chromatography and spectrometry techniques. Results of the study found sarcophytol derivatives (sarcophytol A, 11,12-epoxy sarcophytol A, sarcophytol B, and sarcophytol M) as the only chemotype in the sample. This may suggest low genetic diversity in the observed Sarcophyton sample. Therefore, it may suggest that even soft coral is known to be resilient to future acidification pressures, the genetic diversity or the production of diverse cytotoxic metabolite may be hampered due to ocean acidification in future climate change adaptation.


Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3457 ◽  
Author(s):  
Te-Sheng Chang ◽  
Chien-Min Chiang ◽  
Yu-Han Kao ◽  
Jiumn-Yih Wu ◽  
Yu-Wei Wu ◽  
...  

Ganoderic acid A (GAA) is a bioactive triterpenoid isolated from the medicinal fungus Ganoderma lucidum. Our previous study showed that the Bacillus subtilis ATCC (American type culture collection) 6633 strain could biotransform GAA into compound (1), GAA-15-O-β-glucoside, and compound (2). Even though we identified two glycosyltransferases (GT) to catalyze the synthesis of GAA-15-O-β-glucoside, the chemical structure of compound (2) and its corresponding enzyme remain elusive. In the present study, we identified BsGT110, a GT from the same B. subtilis strain, for the biotransformation of GAA into compound (2) through acidic glycosylation. BsGT110 showed an optimal glycosylation activity toward GAA at pH 6 but lost most of its activity at pH 8. Through a scaled-up production, compound (2) was successfully isolated using preparative high-performance liquid chromatography and identified to be a new triterpenoid glucoside (GAA-26-O-β-glucoside) by mass and nuclear magnetic resonance spectroscopy. The results of kinetic experiments showed that the turnover number (kcat) of BsGT110 toward GAA at pH 6 (kcat = 11.2 min−1) was 3-fold higher than that at pH 7 (kcat = 3.8 min−1), indicating that the glycosylation activity of BsGT110 toward GAA was more active at acidic pH 6. In short, we determined that BsGT110 is a unique GT that plays a role in the glycosylation of triterpenoid at the C-26 position under acidic conditions, but loses most of this activity under alkaline ones, suggesting that acidic solutions may enhance the catalytic activity of this and similar types of GTs toward triterpenoids.


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