Medicine in Mucus? Don’t believe me ask the Elasmobranchs.

It’s becoming increasingly prevalent the importance and diversity of the marine environment and in more recent times the marine microbial world. This is due to the genetic and metabolic diversity of marine microbes and their capability of producing numerous chemical compounds, many of which could have a use within our society. This study explores using marine microbes for human medicine in the field of antibiotic production and wound healing. The authors specifically investigating the mutualistic interaction between the Elasmobranchs and the bacteria found in their epidermal mucus.

In the Study 4 Elasmobranch species mucus's were investigated as a source of antibiotic activity against several known infectious human pathogens. This concept has been previously investigated in other species such as Elkhorn coral (Acropora palmate), Ritchie(2006) found that over 20% of bacteria isolated from the mucus demonstrated antibiotic activity. Another study testing fish mucus was Bergsson et al (2005) in which they found numerous bacteria in the mucus of the Atlantic cod (Gadus morhu) which had potential for antibiotic activity. The Elasmobranchs are a great test species due to their known ability to heal quickly and efficiently as well as generally low wound infection rates indicating possible bacterial mutualism.

The test species used were the Cownose ray (Rhinoptera bonasus), Devil ray(Mobula hypostoma), Marine Atlantic ray as well as the freshwater Atlantic ray (Dasyatis Sabina) and the Clearnose skate (Raja eglanteria). All of which can be found off the Gulf of Mexico. Of these sample species the collection and sampling methods varied , with 3 of the organisms being sampled and released at time of capture and the other 2 species being bought back to the lab for sampling. Regardless of collection method  all samples were obtained by the passive scraping of the mucus on the pectoral fin surface. Once collected the samples were transferred to sterile culture tubes before being centrifuged to separate the mucus. Theses samples were then serially diluted and then cultures were grown, isolating the mucus associated bacteria for further tests.

The isolated colonies were then analysed for antibacterial properties against pathogenic and non-pathogenic strains. After this initial testing the bacteria exhibiting antibiotic production were further characterized by testing for blood lysis potential and production of antimicrobial peptides. The DNA from the pure samples of all antibiotic producing isolates were extracted using a power soil DNA extracting kit. The 16S rRNA genes  were then amplified using PCR with the results of being sent for analysis at ULUC core sequencing facilities. Sequences were analysed using the GenBank Basic Local Alignment Tool- BLAST to determine % similarity of the sampled bacteria to the international bacteria database.

In this study every elasmobranch tested had mucus associated bacteria that displayed antibiotic activity against common pathogens. Collectively over 16% of the bacterial isolates showed antibiotic activity against certain common pathogens ,with 3% of these showing broad spectrum antibiotic activity or specific activity against VRE or MRSA.These bacteria were from 5 different genera.

This study could help with targeting bacterial growth conditions for further antibiotic screening and advances in medical studies .Although in early stages it highlights the need and opportunity for future work in this field which could lead to huge advances in antibiotic development. The study was funded by the department of defence for possible advances in wound healing and control of infection in a military capacity, I think this shows the scope that marine research is beginning to have in all fields and how important it could be to human medicine in years to come.

Reviewed Paper

Ritchie, K., Schwarz, M., Mueller, J., Lapacek, V., Merselis, D., Walsh, C. and Luer, C. (2017). Survey of Antibiotic-producing Bacteria Associated with the Epidermal Mucus Layers of Rays and Skates. Frontiers in Microbiology, 8.

https://www.frontiersin.org/articles/10.3389/fmicb.2017.01050/full#B23

Works Cited

Bergsson, G., Agerberth, B., Jörnvall, H. and Gudmundsson, G. H. (2005), Isolation and identification of antimicrobial components from the epidermal mucus of Atlantic cod (Gadus morhua). FEBS Journal, 272: 4960–4969. doi:10.1111/j.1742-4658.2005.04906x

http://onlinelibrary.wiley.com/doi/10.1111/j.1742-4658.2005.04906.x/full

Ritchie, K. (2006). Regulation of microbial populations by coral surface mucus and mucus-associated bacteria. Marine Ecology Progress Series, 322, 1-14. Retrieved from http://www.jstor.org/stable/24870854