scholarly journals Lipid composition of the microbial mat from a hypersaline environment (Vermelha Lagoon, Rio de Janeiro, Brazil)

2021 ◽  
Vol 91 (3) ◽  
pp. 349-361
Author(s):  
TAIS FREITAS DA SILVA ◽  
SINDA BEATRIZ CARVALHAL GOMES ◽  
FREDERICO SOBRINHO DA SILVA ◽  
KSENIJA STOJANOVIĆ ◽  
ROSANE NORA CASTRO ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Rio De Janeiro ◽  
Microbial Mat ◽  
Lipid Classes ◽  
Source Rocks ◽  
Hypersaline Environment ◽  
Purple Sulfur Bacteria ◽  
Sulfate Reducing ◽  
Sulfur Bacteria ◽  
Different Color

Abstract This study determines organic-matter (OM) composition in the different color layers of a stratified hypersaline microbial mat and verifies the hypothesis that each layer includes a distinct group of lipids. The relation of precursor lipids from the microbial mat to the hydrocarbon composition in fossil records was also evaluated. To that end, the composition was studied of glycolipids (GLs), phospholipids (PLs), and “neutral” lipids (NLs, including hydrocarbons, n-alkanols, sterols, hopanols, free fatty acids, and wax esters) in four different color layers (A–D; depth intervals: up to 0.5 cm, 0.5–1.0 cm, 1.5–3.0 cm, and 3.0–6.0 cm, respectively) of a stratified hypersaline mat from the Vermelha Lagoon, Rio de Janeiro, Brazil. Microscopic characterization revealed the presence of 16 cyanobacterial morphospecies, with predominance of Microcoleus chthonoplastes. The notable prevalence of saturated straight-chain fatty acids (FAs), n-16:0 and n-18:0 and their monounsaturated counterparts, n-16:1 and n-18:1 in all three lipid fractions (GLs, PLs, and NLs), associated with the domination of n-C17 alkane and n-C17:1 alkene among the hydrocarbons confirmed the main imprint of cyanobacteria. The composition of the studied lipid classes implies the contribution of sulfate-reducing bacteria such as Desulfomicrobium sp. strain, purple sulfur bacteria, as well as the possible input of Geobacter spp. and Desulfovibrio spp., particularly in the deeper layers. The notable decrease in total extractable lipids (TELs) yield from layers A to D indicates that lipid synthesis is far more intense by photosynthesizing cyanobacteria than by anaerobic microorganisms. The content of PLs was uniform and low (< 5%) in all layers, implying their extremely quick degradation. GLs, followed by NLs, were the most abundant in all layers indicating the medium, which is characterized by carbon source excess and limited nitrogen source, which regulates microorganism growth. The upper layers, A (green) and B (reddish-brown) differ from those lower, C (dark brown greenish) and D (brown) according to the NLs/GLs ratio, which is higher in the former. The lipid compositions reveal distinctions between the individual layers in the microbial mat. The observed layers clearly differ according to the amount of high-molecular-weight (C22–C31) n-alkanes and long-chain (C21–C30) n-alkanols, the content of phytol, bishomohopanol, tetrahymanol, C27–C29 sterols, the stanol/stenol ratio in the neutral lipid fraction, as well as the content of branched (iso and anteiso) FAs and w9/w7 FA ratio in the GLs fraction. The mentioned parameters imply a greater contribution of sulfate-reducing and purple sulfur bacteria to layer B, higher impact of photosynthetic red algae in upper layers A and B, the elevated contribution of marine ciliate species, feeding on bacteria to layers B and C, as well as the increment of anoxygenic phototrophic and heterotrophic bacteria to layer D. The greatest capability for the synthesis of hydrocarbons is observed in layer B. The composition of lipid classes in the microbial mat showed a significant relationship with the most important biomarkers' fingerprints in the source rocks extracts and petroleum derived from the carbonate hypersaline environments, including the distribution of n-alkanes, a high abundance of phytane and gammacerane, as well as a distribution of C27–C29 regular steranes. Therefore, these results offer an insight into the transformation of microbial OM during the sedimentation processes in a hypersaline environment and its contribution to the fossil record.

A Study of the Performance of a High-Rate Photosynthetic Pond System

1987 ◽  
Vol 19 (12) ◽  
pp. 237-241 ◽  
Author(s):  
H. M. Pinheiro ◽  
M. T. Reis ◽  
J. M. Novais
Keyword(s):  
Sulfate Reducing Bacteria ◽  
Operating Conditions ◽  
High Rate ◽  
Purple Sulfur Bacteria ◽  
Residence Times ◽  
Sulfate Reducing ◽  
Pond System ◽  
Sulfur Bacteria ◽  
Colour Changes ◽  
Reducing Bacteria

Colour changes and other marked disturbances were observed at a high-rate photosynthetic pond system at Alcochete, Portugal. Previous chemical and microbiological tests made it possible to attribute these occurrences to the proliferation of purple sulfur bacteria, following the probable production of sulfide inside the ponds by sulfate-reducing bacteria. Results from more recent tests and observations are presented, which confirm the earlier conclusions, in addition to revealing a number of inadequacies in the ponds chosen operating conditions, which are in all probability at the origin of the observed disturbances. Corrective actions planned include a more efficient mixing of pond contents, the strict prevention of contamination with salty estuarine waters and the control of residence times and bottom sludge accumulation.

scholarly journals Anaerobic 1-Alkene Metabolism by the Alkane- and Alkene-Degrading Sulfate Reducer Desulfatibacillum aliphaticivorans Strain CV2803T

2007 ◽  
Vol 73 (24) ◽  
pp. 7882-7890 ◽  
Author(s):  
Vincent Grossi ◽  
Cristiana Cravo-Laureau ◽  
Alain Méou ◽  
Danielle Raphel ◽  
Frédéric Garzino ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Inorganic Carbon ◽  
Direct Evidence ◽  
Gas Chromatography Mass Spectrometry ◽  
Sulfate Reducing ◽  
Branched Fatty Acids ◽  
Initial Activation ◽  
Fumarate Addition ◽  
Chain Lengths ◽  
Methyl Branched Fatty Acids

ABSTRACT The alkane- and alkene-degrading, marine sulfate-reducing bacterium Desulfatibacillum aliphaticivorans strain CV2803T, known to oxidize n-alkanes anaerobically by fumarate addition at C-2, was investigated for its 1-alkene metabolism. The total cellular fatty acids of this strain were predominantly C-(even number) (C-even) when it was grown on C-even 1-alkenes and predominantly C-(odd number) (C-odd) when it was grown on C-odd 1-alkenes. Detailed analyses of those fatty acids by gas chromatography-mass spectrometry after 6- to 10-week incubations allowed the identification of saturated 2- and 4-ethyl-, 2- and 4-methyl-, and monounsaturated 4-methyl-branched fatty acids with chain lengths that correlated with those of the 1-alkene. The growth of D. aliphaticivorans on (per)deuterated 1-alkenes provided direct evidence of the anaerobic transformation of these alkenes into the corresponding 1-alcohols and into linear as well as 10- and 4-methyl-branched fatty acids. Experiments performed with [13C]bicarbonate indicated that the initial activation of 1-alkene by the addition of inorganic carbon does not occur. These results demonstrate that D. aliphaticivorans metabolizes 1-alkene by the oxidation of the double bond at C-1 and by the subterminal addition of organic carbon at both ends of the molecule [C-2 and C-(ω-1)]. The detection of ethyl-branched fatty acids from unlabeled 1-alkenes further suggests that carbon addition also occurs at C-3. Alkylsuccinates were not observed as potential initial intermediates in alkene metabolism. Based on our observations, the first pathways for anaerobic 1-alkene metabolism in an anaerobic bacterium are proposed. Those pathways indicate that diverse initial reactions of 1-alkene activation can occur simultaneously in the same strain of sulfate-reducing bacterium.

scholarly journals Maternal Lipidomic Signatures in Relation to Spontaneous Preterm Birth and Large-For-Gestational Age Neonates

2021 ◽  
Author(s):  
Max Aung ◽  
Pahriya Ashrap ◽  
Deborah Watkins ◽  
Bhramar Mukherjee ◽  
Zaira Rosario ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Preterm Birth ◽  
Free Fatty Acids ◽  
Gestational Age ◽  
Pregnancy Outcomes ◽  
Lipid Analysis ◽  
Lipid Classes ◽  
Large For Gestational Age ◽  
Spontaneous Preterm Birth ◽  
Increased Risk

Abstract Background: Lipidome-wide metabolites may be useful biomarkers of pregnancy outcomes. We sought to characterize maternal lipidomic signatures associated with preterm birth and neonatal anthropometric parameters. Methods: Plasma samples were collected 24-28 weeks gestation, and lipidomic profiling was quantified using high-performance liquid chromatography tandem mass spectrometry. Lipid metabolites were analyzed individually and as whole lipid classes and subgroups based on degree of hydrocarbon chain saturation. Associations were estimated using linear and logistic regression.Results: After false discovery adjustment (q<0.15), four plasmenyl-phosphatidylethanolamines and three free fatty acids associated with increased risk for spontaneous preterm birth. Five phosphatidylinositols, two phosphatidylglycerols, and one phosphatidic acid were associated with large for gestational age neonates. The saturated plasmenyl-phosphatidylethanolamines held the association with increased risk for spontaneous preterm birth. Both the mono- and poly-unsaturated free fatty acids held the association for increased risk for spontaneous preterm birth. Mono- and poly-unsaturated phosphatidylinositols were associated with large for gestational age neonates. Whole lipid classes (plasmenyl-phophatidylcholines and plasmenyl-phosphatidylethanolamines) were associated with increased risk for large for gestational age at delivery.Conclusions: This study provides evidence that finer omics-scale analysis of the maternal lipidome may be more informative biomarkers of pregnancy outcomes compared to whole class level lipid analysis.

scholarly journals Content and composition of lipid classes, fatty acid from \(\textit{Sargassum}\) seaweed collected at Con Dao and Van Phong bay

2021 ◽  
Vol 21 (3) ◽  
pp. 311-318
Author(s):  
Thu Hue Pham ◽  
Van Tuyen Anh Nguyen Nguyen ◽  
Yen Kieu Thi Hoang ◽  
Nguyen Nguyen ◽  
Hai Nam Hoang ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Total Lipid ◽  
Polar Lipid ◽  
Brown Seaweed ◽  
Monounsaturated Fatty Acids ◽  
Lipid Classes ◽  
Average Content ◽  
Fresh Weight

This study studied the content and composition of the total lipid, lipid classes and fatty acids in 13 brown seaweed Sargassum species collected from Con Dao and Van Phong, Vietnam. The total lipid has a low content and varies among species from 0.10–1.70% of the fresh weight. From 13 species, seven lipid classes including polar lipid (Pol), free fatty acids (FFA), sterol (ST), hydrocarbon and wax (HW), triacylglycerol (TG), diacylglycerol (DG), and monoalkydiacylglycerol (MADG). Using the GC-FID technique, we have identified 29 fatty acids classified into 3 groups of saturated fatty acid, monounsaturated fatty acids, polyunsaturated fatty acids with an average content of 44.93%, 24.57% and 27.44%, respectively. Among those, many value fatty acids have been detected with high content such as C18:3n-3, C20:4n-6, 20:5n-3, and 22:6n-3. The lipid of 13 brown seaweed Sargassum species also fully contains omega-3,6,9 fatty acids with the content of 9.28%, 16.28% and 16.63%, respectively.

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