What were the results of your 16S analysis?
All four of my isolates, #13, 14, 15, and 17, did have PCR products, but I was only able to obtain the 16S rRNA gene sequence for #13, 14, and 15. When we looked at the PCR products on a gel, #17 did produce a band, but it was faint which could explain why it wasn’t able to be sequenced. BLAST showed that #13 has a 99% match with the Bacillus genus. Isolate #14 had a 99% match with the Pseudomonas genus, and #15 had a 99% match with the Staphylococcus genus.
Does your gram stain agree?
My gram stain agreed for all three of my isolates. The gram stain for isolate #13 showed it was a gram-positive, rod shaped bacteria. This matches the description for the bacteria in the Bacillus genus (1). The gram stain for isolate #14 showed it was a gram-negative, rod shaped bacteria. This also matches the description for bacteria in the Pseudomonas genus (2). The gram stain for #15 showed it was a gram-positive, coccus shaped bacteria which clumped together in random numbers. This matches the description for bacteria in the Staphylococcus genus (3).
a) General cellular and morphological characteristics of the genus (taxonomic classification, nutrition, cell shape, habitat).
I further researched the characteristics of the Pseudomonas genus which matched my isolate #14. The taxonomic classification for this is Bacteria kingdom, Proteobacteria phylum, Gammaproteobacteria class, Pseudomonadales order, Pseudomonadacae family, and Pseudomonas genus (4). They are gram-negative, straight or slightly curved rods (2). They are typically aerobic, although sometimes nitrate can be used as an alternate electron acceptor which allows it to grow anaerobically (2). Most species can not grow under acidic conditions and do not require organic growth factors (2). This bacteria is widely distributed in nature and some species within this genus are pathogenic for humans, animals, or plants (2).
b) Information regarding antibiotic production in this genus.
Pseudomonas have been found to produce a wide variety of antibiotics including mupirocin (a topical antibiotic), fosfadecin, fosfocytosin, and xantholysins (4). Xantholysins have been discovered more recently and have shown anti-fungal activity and antibiotic activity, specifically against gram positive bacteria. Pseudomonas fluorescens has been shown to produce the antibiotics pyrrolnitrin, pyoluteorin, and 2,4-diacetylphloroglucinol (5). It is encouraging to know that this genus has shown antibiotic production since my isolate appeared to show antibiotic production.
References
1) Liu, Y., et. al, Proposal of nine novel species of the Bacillus cereus group, International Journal of Systematic and Evolutionary Microbiology, 2017
2) Palleroni, N. J. (2015). Pseudomonas. In Bergey’s Manual of Systematics of Archaea and Bacteria (eds W. B. Whitman, F. Rainey, P. Kämpfer, M. Trujillo, J. Chun, P. DeVos, B. Hedlund and S. Dedysh).
3) Pantucek, R., et. al, Staphylococcus edaphicus sp. nov., isolated in Antarctica, harbours mecC gene and genomic islands with suspected role in adaptation to extreme environment., Applied and Environmental Microbiology, 2017
4) Javier Pascual, Marina García-López, Cristina Carmona, Thiciana da S. Sousa, Nuria de Pedro, Bastien Cautain, Jesús Martín, Francisca Vicente, Fernando Reyes, Gerald F. Bills, Olga Genilloud,
Pseudomonas soli sp. nov., a novel producer of xantholysin congeners, Systematic and Applied Microbiology, Volume 37, Issue 6, 2014, Pages 412-416
5) Sarniguet, A., et. al, The sigma factor sigma s affects antibiotic production and biological control activity of Pseudomonas fluorescens Pf-5, Proceedings of the National Academy of Sciences, 1995
