Adaptive responses of free‐living and symbiotic microalgae to simulated future ocean conditions

2021 ◽  
Vol 27 (9) ◽  
pp. 1737-1754
Author(s):  
Wing Yan Chan ◽  
John G. Oakeshott ◽  
Patrick Buerger ◽  
Owain R. Edwards ◽  
Madeleine J. H. Oppen
Keyword(s):  
Adaptive Responses ◽  
Free Living ◽  
Ocean Conditions ◽  
Symbiotic Microalgae

scholarly journals The FtcR-Like Protein ActR in Azorhizobium caulinodans ORS571 Is Involved in Bacterial Motility and Symbiosis With the Host Plant

2021 ◽  
Vol 12 ◽  
Author(s):  
Li Sun ◽  
Dandan Wang ◽  
Zhiqiu Yin ◽  
Chengsheng Zhang ◽  
Amber Bible ◽  
...  
Keyword(s):  
Host Plant ◽  
Brucella Melitensis ◽  
Transcriptional Regulator ◽  
Adaptive Responses ◽  
Azorhizobium Caulinodans ◽  
Free Living ◽  
Bacterial Flagellum ◽  
Flagellar Biosynthesis ◽  
Living State ◽  
Two Component Systems

Bacterial signal transduction pathways are important for a variety of adaptive responses to environment, such as two-component systems (TCSs). In this paper, we reported the characterization of a transcriptional regulator in Azorhizobium caulinodans ORS571, ActR, with an N-terminal receiver domain and one C-terminal OmpR/PhoB-type DNA binding domain. Sequence analysis showed that ActR shared a high similarity with FtcR regulator of Brucella melitensis 16M known to be involved in flagellar regulation. The structural gene of this regulator was largely distributed in Alphaproteobacteria, in particular in Rhizobiales and Rhodobacterales, and was located within clusters of genes related to motility functions. Furthermore, we studied the biological function of ActR in A. caulinodans grown at the free-living state or in association with Sesbania rostrata by constructing actR gene deletion mutant. In the free-living state, the bacterial flagellum and motility ability were entirely deleted, the expression of flagellar genes was downregulated; and the exopolysaccharide production, biofilm formation, and cell flocculation decreased significantly compared with those of the wild-type strain. In the symbiotic state, ΔactR mutant strain showed weakly competitive colonization and nodulation on the host plant. These results illustrated that FtcR-like regulator in A. caulinodans is involved in flagellar biosynthesis and provide bacteria with an effective competitive nodulation for symbiosis. These findings improved our knowledge of FtcR-like transcriptional regulator in A. caulinodans.

scholarly journals Subcellular architecture and metabolic connection in the planktonic photosymbiosis between Collodaria (radiolarians) and their microalgae

2021 ◽  
Author(s):  
Johan Decelle ◽  
Giulia Veronesi ◽  
Charlotte LeKieffre ◽  
Benoit Gallet ◽  
Fabien Chevalier ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Iron Concentration ◽  
Photosynthetic Apparatus ◽  
Stable Isotope Probing ◽  
Host Cells ◽  
Intracellular Iron ◽  
Free Living ◽  
3D Electron Microscopy ◽  
Algal Metabolism ◽  
Symbiotic Microalgae

Photosymbiosis is widespread and ecologically important in the oceanic plankton but remains poorly studied. Here, we used multimodal subcellular imaging to investigate the photosymbiosis between colonial Collodaria and their microalga dinoflagellate (Brandtodinium) collected in surface seawaters. We showed that this symbiosis is a very dynamic system whereby symbionts interact with different host cells via extracellular vesicles within the greenhouse-like colony. 3D electron microscopy revealed that the volume of the photosynthetic apparatus (plastid and pyrenoid) of the microalgae increased in symbiosis compared to free-living while the mitochondria volume was similar. Stable isotope probing coupled with NanoSIMS showed that carbon and nitrogen were assimilated and stored in the symbiotic microalga in starch granules and purine crystals, respectively. Nitrogen was also allocated to the algal nucleus (nucleolus). After 3 hours, low 13C and 15N transfer was detected in the host Golgi. Metal mapping revealed that intracellular iron concentration was similar in free-living and symbiotic microalgae (ca 40 ppm) and two-fold higher in the host, whereas copper concentration increased in symbiotic microalgae (up to 6900 ppm) and was detected in the host cell and extracellular vesicles. Sulfur mapping also pinpointed the importance of this nutrient for the algal metabolism. This study, which revealed subcellular changes of the morphology and nutrient homeostasis in symbiotic microalgae, improves our understanding on the metabolism of this widespread and abundant oceanic symbiosis and paves the way for more studies to investigate the metabolites exchanged.

scholarly journals Cytochrome P450 monooxygenase analysis in free-living and symbiotic microalgae Coccomyxa sp. C-169 and Chlorella sp. NC64A

ALGAE ◽  
2015 ◽  
Vol 30 (3) ◽  
pp. 233-239 ◽  
Author(s):  
Ntsane Trevor Mthakathi ◽  
Ipeleng Kopano Rosinah Kgosiemang ◽  
Wanping Chen ◽  
Molikeng Eric Mohlatsane ◽  
Thebeyapelo Jacob Mojahi ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Cytochrome P450 Monooxygenase ◽  
Free Living ◽  
P450 Monooxygenase ◽  
Chlorella Sp ◽  
Symbiotic Microalgae

Ultrastructure of neuromuscular relationships in the canine heartworm (dirofilaria immitis)

1986 ◽  
Vol 44 ◽  
pp. 278-279
Author(s):  
W. L. Steffens ◽  
Nancy B. Roberts ◽  
J. M. Bowen
Keyword(s):  
Dirofilaria Immitis ◽  
Domestic Dogs ◽  
Structural Description ◽  
Pharmacological Effects ◽  
Free Living ◽  
Canine Heartworm ◽  
The World ◽  
Synaptic Region ◽  
Muscle Innervation ◽  
Insight Into

The canine heartworm is a common and serious nematode parasite of domestic dogs in many parts of the world. Although nematode neuroanatomy is fairly well documented, the emphasis has been on sensory anatomy and primarily in free-living soil species and ascarids. Lee and Miller reported on the muscular anatomy in the heartworm, but provided little insight into the peripheral nervous system or myoneural relationships. The classical fine-structural description of nematode muscle innervation is Rosenbluth's earlier work in Ascaris. Since the pharmacological effects of some nematacides currently being developed are neuromuscular in nature, a better understanding of heartworm myoneural anatomy, particularly in reference to the synaptic region is warranted.

Lead and lead toxicity in domestic and free living birds

2003 ◽  
Vol 32 (1) ◽  
pp. 3-13 ◽  
Author(s):  
N. De Francisco ◽  
N. De Francisco ◽  
N. De Francisco
Keyword(s):  
Lead Toxicity ◽  
Free Living

Platelet Aggregation in Finnish Men and Its Relation to Fatty Acids in Platelets, Plasma and Adipose Tissue

1985 ◽  
Vol 54 (03) ◽  
pp. 563-569 ◽  
Author(s):  
M K Salo ◽  
E Vartiainen ◽  
P Puska ◽  
T Nikkari
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Platelet Aggregation ◽  
Acid Composition ◽  
Saturated Fatty Acids ◽  
Free Living ◽  
Ω3 Fatty Acids ◽  
Induced Aggregation

SummaryPlatelet aggregation and its relation to fatty acid composition of platelets, plasma and adipose tissue was determined in 196 randomly selected, free-living, 40-49-year-old men in two regions of Finland (east and southwest) with a nearly twofold difference in the IHD rate.There were no significant east-southwest differences in platelet aggregation induced with ADP, thrombin or epinephrine. ADP-induced platelet secondary aggregation showed significant negative associations with all C20-C22 ω3-fatty acids in platelets (r = -0.26 - -0.40) and with the platelet 20: 5ω3/20: 4ω 6 and ω3/ ω6 ratios, but significant positive correlations with the contents of 18:2 in adipose tissue (r = 0.20) and plasma triglycerides (TG) (r = 0.29). Epinephrine-induced aggregation correlated negatively with 20: 5ω 3 in plasma cholesteryl esters (CE) (r = -0.23) and TG (r = -0.29), and positively with the total percentage of saturated fatty acids in platelets (r = 0.33), but had no significant correlations with any of the ω6-fatty acids. Thrombin-induced aggregation correlated negatively with the ω3/6ω ratio in adipose tissue (r = -0.25) and the 20: 3ω6/20: 4ω 6 ratio in plasma CE (r = -0.27) and free fatty acids (FFA) (r = -0.23), and positively with adipose tissue 18:2 (r = 0.23) and 20:4ω6 (r = 0.22) in plasma phospholipids (PL).The percentages of prostanoid precursors in platelet lipids, i. e. 20: 3ω 6, 20: 4ω 6 and 20 :5ω 3, correlated best with the same fatty acids in plasma CE (r = 0.32 - 0.77) and PL (r = 0.28 - 0.74). Platelet 20: 5ω 3 had highly significant negative correlations with the percentage of 18:2 in adipose tissue and all plasma lipid fractions (r = -0.35 - -0.44).These results suggest that, among a free-living population, relatively small changes in the fatty acid composition of plasma and platelets may be reflected in significant differences in platelet aggregation, and that an increase in linoleate-rich vegetable fat in the diet may not affect platelet function favourably unless it is accompanied by an adequate supply of ω3 fatty acids.

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