Fig 1.
Lateral diagram (A) and oral surface photograph (B) of a C. xamachana medusa.
Note that the oral surface of C. xamachana will usually be oriented towards the water surface to collect sunlight. The muscular bell contracts to increase water flow over the oral surface and help the oral arms collect food from the water, while the laplet function remains uncharacterized. Gonads are subsurface structures and cannot be viewed from the oral surface.
Fig 2.
Bacterial community composition as determined by the V4 region of the 16S rRNA gene.
The bacterial community was dominated by Pseudomonadota in all sample types (A). However, the taxa within the Gammaproteobacteria (B) and Alphaproteobacteria (C) varied between larval and medusa samples (taxa unique to larvae highlighted in yellow in B and C). Please note the varying Y axes in B and C. The “Other” category (A) includes taxa present at less than 2% average relative abundance in all 5 categories, including members of the Betaproteobacteria class, and the Gracilibacteria, Balneolota, Chlamydiota, Spirochaetota, Cyanobacteriota, and Chloroflexota phyla, which were just below this threshold. The Parvarchaea class of Euryarcheaota is also included in the “Other” designation. o: order, f: family, g: genus.
Fig 3.
Alpha and beta diversity analyses of the C. xamachana bacterial community.
Bacterial community composition varied between larva and medusa samples (A), but not between medusa structures (gonad, bell, arm, D) when analyzed via the Bray Curtis beta diversity metric. ANOSIM results are included in parentheses in NMDS plots (A, D). Larvae and medusae had similar alpha diversity as evaluated by unpaired t-test analyses of the Chao1 (B) and Phylogenetic Diversity (C) metrics. Medusa alpha diversity did not vary by medusa structure as evaluated by one-way ANOVA of the Chao1 (E) and Phylogenetic Diversity (F) metrics.
Table 1.
NCBI reference sequences used in phylogenetic tree to identify isolates. All included taxonomic identifications are based on NCBI published records.
Fig 4.
Maximum likelihood unrooted phylogenetic tree of 16S rRNA gene from C. xamachana bacterial isolates and reference sequences.
Bootstrap values based on 100 replicates. Clade coloration indicates larger bacterial groups, either class or phylum. Metabolic characteristic results indicated by colored boxes next to the isolates selected for that study, legend at upper left. A white box indicates a negative result for the test, a box with a slash indicates no data was collected for that test. First character of isolate code represents male (M) or female (F) jellyfish, second character represents arm (A), bell (B), or laplet (L) structure, and third character indicates jellyfish individual. Bolded species names are reference sequences from NCBI (see Table 1). Bottom left scale bar indicates genetic distance.
Fig 5.
Mosaic plots showing the distribution of isolates testing positive (darker shade) or negative (lighter shade) for a given characteristic, divided by sex (Y axis: male in blue, female in yellow) and by medusa structure (X axis). Five metabolic characteristics were tested (A: siderophore production; B: nitrate reduction; C: lactose fermentation; D: amylase production; E: gelatinase production), and the distribution of isolates identified as members of the Endozoicomonas genus was also examined (F). Chi-squared results based on sex and structure groups are shown. Lactose fermentation was significantly more common in females than males when only sex was considered ( = 5.449, p = 0.02), while gelatinase production was significantly more common in laplets than in arms or bells (
= 6.046, p = 0.049). A principal component analysis of isolate metabolic characteristics (those shown in A-F, as well as sulfur reduction, capsule presence, motility, glucose and sucrose fermentation, indole production, caseinase production, and catalase production) demonstrated no clustering by sex (color, 95% confidence intervals) and/or structure (shape, G).