Seaweeds agarophytes and associated epiphytic bacteria along Alexandria coastline, Egypt, with emphasis on the evaluation and extraction of agar and agarose

Ibrahim, Hassan A.H.; Beltagy, Ehab A.; El-Din, Nihal G. Shams; Zokm, Gehan M. El; El-Sikaily, Amany; Abu-Elela, Gehan M

doi:10.4067/s0718-19572015000400012

Cited by 14 publications

(7 citation statements)

References 22 publications

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“…Juvenile green turtles are not gregarious, but may form dense aggregations [ 31 , 76 ], which might facilitate feces consumption and hence the quick acquisition of a bacterial flora adapted to digest polysaccharides. Alternatively, fermenters might be transferred through the diet, as they can be associated with algal surfaces [ 77 ].…”

Section: Discussionmentioning

confidence: 99%

Fast acquisition of a polysaccharide fermenting gut microbiome by juvenile green turtles Chelonia mydas after settlement in coastal habitats

et al. 2018

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BackgroundTetrapods do not express hydrolases for cellulose and hemicellulose assimilation, and hence, the independent acquisition of herbivory required the establishment of new endosymbiotic relationships between tetrapods and microbes. Green turtles (Chelonia mydas) are one of the three groups of marine tetrapods with an herbivorous diet and which acquire it after several years consuming pelagic animals. We characterized the microbiota present in the feces and rectum of 24 young wild and captive green turtles from the coastal waters of Brazil, with curved carapace length ranging from 31.1 to 64.7 cm, to test the hypotheses that (1) the ontogenetic dietary shift after settlement is followed by a gradual change in the composition and diversity of the gut microbiome, (2) differences exist between the composition and diversity of the gut microbiome of green turtles from tropical and subtropical regions, and (3) the consumption of omnivorous diets modifies the gut microbiota of green turtles.ResultsA genomic library of 2,186,596 valid bacterial 16S rRNA reads was obtained and these sequences were grouped into 6321 different operational taxonomic units (at 97% sequence homology cutoff). The results indicated that most of the juvenile green turtles less than 45 cm of curved carapace length exhibited a fecal microbiota co-dominated by representatives of the phyla Bacteroidetes and Firmicutes and high levels of Clostridiaceae, Prophyromonas, Ruminococaceae, and Lachnospiraceae within the latter phylum. Furthermore, this was the only microbiota profile found in wild green turtles > 45 cm CCL and in most of the captive green turtles of any size feeding on a macroalgae/fish mixed diet. Nevertheless, microbial diversity increased with turtle size and was higher in turtles from tropical than from subtropical regions.ConclusionsThese results indicate that juvenile green turtles from the coastal waters of Brazil had the same general microbiota, regardless of body size and origin, and suggest a fast acquisition of a polysaccharide fermenting gut microbiota by juvenile green turtles after settlement into coastal habitats.Electronic supplementary materialThe online version of this article (10.1186/s40168-018-0454-z) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Fast acquisition of a polysaccharide fermenting gut microbiome by juvenile green turtles Chelonia mydas after settlement in coastal habitats

et al. 2018

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“…These species can be dominant components of coastal habitats and act as ecological engineers. Some species serve communities as nurseries for intertidal invertebrates, host diverse microbial communities, and provide food for marine grazers such as green turtles, fishes, gastropods, and sea urchins ( Felicini and Perrone, 1994 ; Ibrahim et al, 2015 ; Campos and Cardona, 2020 ; Patarra et al, 2020 ). Although the genus, like most red algae, has a triphasic life cycle comprising tetrasporophytes, sexual gametophytes, and carposporophytes, male and female plants are rarely found in most species ( Boo et al, 2010 , 2017 ; Iha et al, 2017 ; Patarra et al, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

Ancient Tethyan Vicariance and Long-Distance Dispersal Drive Global Diversification and Cryptic Speciation in the Red Seaweed Pterocladiella

et al. 2022

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We investigated the globally distributed red algal genus Pterocladiella, comprising 24 described species, many of which are economically important sources of agar and agarose. We used DNA-based species delimitation approaches, phylogenetic, and historical biogeographical analyses to uncover cryptic diversity and infer the drivers of biogeographic patterns. We delimited 43 species in Pterocladiella, of which 19 are undescribed. Our multigene time-calibrated phylogeny and ancestral area reconstruction indicated that Pterocladiella most likely originated during the Early Cretaceous in the Tethys Sea. Ancient Tethyan vicariance and long-distance dispersal have shaped current distribution patterns. The ancestor of Eastern Pacific species likely arose before the formation of the formidable Eastern Pacific Barrier—a first confirmation using molecular data in red algae. Divergences of Northeast and Southeast Pacific species have been driven by the Central American Seaway barrier, which, paradoxically, served as a dispersal pathway for Atlantic species. Both long- and short-distance dispersal scenarios are supported by genetic relationships within cosmopolitan species based on haplotype analysis. Asymmetrical distributions and the predominance of peripatry and sympatry between sister species suggest the importance of budding speciation in Pterocladiella. Our study highlights the underestimation of global diversity in these crucial components of coastal ecosystems and provides evidence for the complex evolution of current species distributions.

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“…Also, increased interest in prospecting and evaluating new Gelidium -based agarophyte resources is emergent in other countries, such as G. spinosum in Tunisia (Ben Said et al 2009, 2013), G. crinale and Pterocladiella capillacea in Egypt (Ibrahim et al 2015), G. crinale in Argentina (Croce et al 2015), G. corneum in Algeria (Nil et al 2016), and G. elegans in Malaysia (Ajdari and Zarshenas 2016). …”

Section: Discussionmentioning

confidence: 99%

Global shortage of technical agars: back to basics (resource management)

Santos

Melo

2018

J Appl Phycol

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Bacteriological and technical agars are in short supply with potential consequences for research, public health, and clinical labs around the world. To diagnose bottlenecks and sustainability problems that may be putting the industry at risk, we analyzed the available time series for the global landings of Gelidium, the most important raw materials for the industry. Data on the harvest of Gelidium spp. have been reported since1912, when Japan was the only producer. After World War II the diversification of harvested species and producing countries resulted in a strong increase in global landings. Maximum harvest yields of almost 60,000 t year−1 in the 1960s were sustained until the 1980s, after which landings decreased continuously to the present. In the 2010s, a reduction in the global production to about 25,000 t year−1 was observed, which was lower than the yields of the 1950s. Landings by important producers such as Japan, Korea, Spain, and Portugal have collapsed. This is the ultimate cause of the present shortage of bacteriological and technical agars. However, an important factor at play is the concentration of the global landings of Gelidium in Morocco, as its relative contribution increased from 23% in the 1960s to the present 82%. Two specific bottlenecks were identified: restrictive export quotas of unprocessed Gelidium in favor of the national agar industry and resource management regulations that were apparently not enforced resulting in over-harvesting and resource decline. The global industry may well be dependent on resource management basics. Simple harvest statistics must be gathered such as the harvest effort and the variation of harvest yields along the harvest season. We discuss how this information is fundamental to manage the resource. The available harvest statistics are generally poor and limited and vary significantly among different sources of data. Probable confusions between dry and wet weight reporting and poor discrimination of the species harvested need to be resolved.

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Seaweeds agarophytes and associated epiphytic bacteria along Alexandria coastline, Egypt, with emphasis on the evaluation and extraction of agar and agarose

Cited by 14 publications

References 22 publications

Fast acquisition of a polysaccharide fermenting gut microbiome by juvenile green turtles Chelonia mydas after settlement in coastal habitats

Fast acquisition of a polysaccharide fermenting gut microbiome by juvenile green turtles Chelonia mydas after settlement in coastal habitats

Ancient Tethyan Vicariance and Long-Distance Dispersal Drive Global Diversification and Cryptic Speciation in the Red Seaweed Pterocladiella

Global shortage of technical agars: back to basics (resource management)

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