Heterotrophic bacteria associated with the green alga Ulva rigida: identification and antimicrobial potential

Ismail, Amel; Ktari, L.; Ahmed, Mehboob; Bolhuis, Henk; Bouhaouala‐Zahar, Balkiss; Stal, Lucas J.; Boudabbous, A.; Bour, Monia El

doi:10.1007/s10811-018-1454-x

Cited by 27 publications

(25 citation statements)

References 64 publications

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“…However, field and experimental studies observed that some genera of polysaccharide-degrading bacteria were more abundant in healthy than diseased tissue (Marzinelli et al, 2015;Zozaya-Valdés et al, 2016) leaving open the possibility that other metabolic capacities are beneficial for their host. Alteromonas (belonging to the same group), for example, showed antimicrobial activity against fish and human pathogens (Ismail et al, 2018), reinforcing the idea that those bacteria are part of the immunity defenses of the holobiont (Hollants et al, 2013).…”

Section: Imta Shapes the Structure Of The Microbial Communitymentioning

confidence: 70%

“…Glaciecola species have been previously isolated from brown macroalgae (Fucus vesiculosus and Laminaria sp.) (Wiese et al, 2009;Goecke et al, 2013), red macroalga Delisea pulchra in aquaria (Zozaya-Valdés et al, 2016), recently from other specimens of U. rigida (Ismail et al, 2018) and diverse marine environments, such as coastal seawater (Chen et al, 2009) and sea sediment (Zhang et al, 2011), antarctic diatom assemblages (Bowman et al, 1998) and marine invertebrates (Romanenko et al, 2003). With their physiological plasticity (psychrophilic behavior) Glaciecola spp.…”

Section: Imta Shapes the Structure Of The Microbial Communitymentioning

confidence: 99%

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Cultivating the Macroalgal Holobiont: Effects of Integrated Multi-Trophic Aquaculture on the Microbiome of Ulva rigida (Chlorophyta)

et al. 2020

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Ulva is a ubiquitous macroalgal genus of commercial interest. Integrated Multi-Trophic Aquaculture (IMTA) systems promise large-scale production of macroalgae due to their high productivity and environmental sustainability. Complex host-microbiome interactions play a decisive role in macroalgal development, especially in Ulva spp. due to algal growth-and morphogenesis-promoting factors released by associated bacteria. However, our current understanding of the microbial community assembly and structure in cultivated macroalgae is scant. We aimed to determine (i) to what extent IMTA settings influence the microbiome associated with U. rigida and its rearing water, (ii) to explore the dynamics of beneficial microbes to algal growth and development under IMTA settings, and (iii) to improve current knowledge of host-microbiome interactions. We examined the diversity and taxonomic composition of the prokaryotic communities associated with wild versus IMTA-grown Ulva rigida and surrounding seawater by using 16S rRNA gene amplicon sequencing. With 3141 Amplicon Sequence Variants (ASVs), the prokaryotic richness was, overall, higher in water than in association with U. rigida. Bacterial ASVs were more abundant in aquaculture water samples than water collected from the lagoon. The beta diversity analysis revealed distinct prokaryotic communities associated with Ulva collected in both aquacultures and coastal waters. Aquaculture samples (water and algae) shared 22% of ASVs, whereas natural, coastal lagoon samples only 9%. While cultivated Ulva selected 239 (8%) host-specific ASVs, wild specimens possessed more than twice host-specific ASVs (17%). Cultivated U. rigida specimens enriched the phyla Cyanobacteria, Planctomycetes, Verrucomicrobia, and Proteobacteria. Within the Gammaproteobacteria, while Glaciecola mostly dominated the microbiome in cultivated algae, the genus Granulosicoccus characterized both Ulva microbiomes. In both wild and IMTA settings, the phylum Bacteroidetes was more abundant in the bacterioplankton than in direct association with U. rigida. However, we observed that the Saprospiraceae family within this phylum was barely present in lagoon

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Section: Imta Shapes the Structure Of The Microbial Communitymentioning

confidence: 70%

Section: Imta Shapes the Structure Of The Microbial Communitymentioning

confidence: 99%

Cultivating the Macroalgal Holobiont: Effects of Integrated Multi-Trophic Aquaculture on the Microbiome of Ulva rigida (Chlorophyta)

et al. 2020

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“…Moreover, we attempted physical cell disruption to release the bacteria from the thallus surface as suggested by Longford et al [60]. Various studies have shown that this technique allows the isolation of DNA from bacteria with complex cell walls (thicker peptidoglycan layers) such as Actinobacteria and Firmicutes, which occur at low densities [61] at the surface of Ulva species [62,63]. Additionally, the methodology used in this study allows DNA clean-up [64,65] throughout the filtration of possible inhibitors such as phenolic and humic compounds that bind to amine groups from the DNA and that negatively affect the PCR reactions [66].…”

Section: Discussionmentioning

confidence: 99%

Two possible candidate enzymes from Ulva lactuca-associated epiphytic bacteria obtained through PCR and functional evaluation

2020

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Epiphytic bacteria from marine macroalgae synthesize enzymes of industrial and biotechnological interest. In this study, we obtained two DNA candidate fragments for lipid-degrading enzymes from the total DNA of Ulva lactuca-associated epiphytic bacteria. First, we evaluated a method for total bacterial DNA isolation from the surface of U. lactuca thalli. Then, we designed sets of primers and used them directly for PCR amplification. The resulting PCR products were sequence-analyzed and used for expression and functional evaluation with the Escherichia coli pBAD-TOPO system. We obtained high molecular weight and good quality total bacterial DNA that served as a template to identify a fragment corresponding to an Acetyl-CoA C-Acetyltransferase (or Thiolase), and a candidate fragment for a versatile “true” lipase. We expressed the possible “true” lipase gene fragment heterologously in Escherichia coli and obtained proof of hydrolytic activity on Tributyrin, Tween-20, and Olive-oil media. This study resulted in new knowledge on U. lactuca-associated epiphytic bacteria as possible brand-new sources of enzymes such as thiolases and “true” lipases. However, future studies are required to describe the characteristics and important applications of these candidate enzymes.

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“…The isolate with the best promoting effect on U. clathrata growth was the Ul‐12, identified as Alteromonas mediterranea . Ismail et al (). isolated Alteromonas sp.…”

Section: Discussionmentioning

confidence: 99%

Growth‐promoting bacteria for the green seaweed Ulva clathrata

et al. 2019

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Seaweed production represents one of the rising activities in the aquaculture industry. This study explores the impact of bacteria associated with the growth of Ulva clathrata, a promising alga in the field of food and bioremediation. Fifty‐six bacteria isolated from four seaweed (Caulerpa sp., Gracilaria sp., Ulva lactuca and U. clathrata) were tested to evaluate their effect on U. clathrata growth. Eight of them showed a significant growth‐promoting effect (p < .05). Isolates Ul‐11 and Ul‐12 from U. lactuca induced an increase of 73 and 81% of growth respectively. They were classified as Reugeria sp. and Alteromonas sp. based on 16S DNA sequencing (>95.0% sequence identity). Multiple combinations of the growth‐promoting bacteria were also tested on U. clathrata, and the best result was achieved by combining Ca‐3/Uc‐18/Ul‐12 isolates with a significant increase in seaweed growth of up to 76%; however, no synergistic effect was observed compared to Ul‐12 alone. Scanning electron microscopy revealed no alteration in the cell wall of U. clathrata when inoculated with selected bacteria, showing an average increase of bacterial density on U. clathrata.

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Heterotrophic bacteria associated with the green alga Ulva rigida: identification and antimicrobial potential

Cited by 27 publications

References 64 publications

Cultivating the Macroalgal Holobiont: Effects of Integrated Multi-Trophic Aquaculture on the Microbiome of Ulva rigida (Chlorophyta)

Cultivating the Macroalgal Holobiont: Effects of Integrated Multi-Trophic Aquaculture on the Microbiome of Ulva rigida (Chlorophyta)

Two possible candidate enzymes from Ulva lactuca-associated epiphytic bacteria obtained through PCR and functional evaluation

Growth‐promoting bacteria for the green seaweed Ulva clathrata

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