Variability among integument microbiomes from different populations of Mugil cephalus
General Material Designation
[Thesis]
First Statement of Responsibility
Shariful Islam
Subsequent Statement of Responsibility
Hoch, Matthew P.
.PUBLICATION, DISTRIBUTION, ETC
Name of Publisher, Distributor, etc.
Lamar University - Beaumont
Date of Publication, Distribution, etc.
2015
PHYSICAL DESCRIPTION
Specific Material Designation and Extent of Item
77
GENERAL NOTES
Text of Note
Committee members: Kucknoor, Ashwini; Lian, Ian
NOTES PERTAINING TO PUBLICATION, DISTRIBUTION, ETC.
Text of Note
Place of publication: United States, Ann Arbor; ISBN=978-1-339-73934-2
DISSERTATION (THESIS) NOTE
Dissertation or thesis details and type of degree
M.S.
Discipline of degree
Biology
Body granting the degree
Lamar University - Beaumont
Text preceding or following the note
2015
SUMMARY OR ABSTRACT
Text of Note
Integument (skin and scales) microbiomes (IM) of fish are deemed important to host immunity. However, few studies have explored how temporal and spatial changes in physicochemical conditions and bacterioplankton communities experienced throughout the life history of the host affect IM community structure. This study defines the IM community structure in populations of juvenile Mugil cephalus (Striped Mullet) at five different saltmarsh sites (SP, KL, SP2, GB, and MF) along the Southeast Texas coast of the Northern Gulf of Mexico. Ten juvenile M. cephalus were collected per site along with water for bacterioplankton analysis and physicochemical measurements. The IMs of individual fish were assessed by denaturing gradient gel electrophoresis of the bacterial 16SrDNA-V3 region, and revealed at least 60% to 75% similarity among IMs of fish per populations based on Sørensen-Dice coefficients. Pearson and Bray-Curtis dissimilarity analysis of DGGE profiles also supported large intra-population variability of IMs, although to a lesser extent for fish populations collected at the SP and KL sites. The bacterial 16SrDNA-V4 region from pooled metagenomic DNAs of the ten fish per site was analyzed by Ion Torrent next generation sequencing. Based on OTUs, the Sørensen-Dice coefficient among pooled IMs was only 25% to 45%, whereas that for bacterioplankton communities was 70% to 85%. There was only about 20% similarity between any pooled IMs and bacterioplankton community. Pearson and Bray-Curtis analyses gave similar trends for both pooled IMs and bacterioplankton communities among sites. This inter-population variation of pooled IMs from different sites appears greater than intra-population variation among individual fish. The most dominant orders (> 3% total sequence reads per order) of IMs included Cytophagales, Rickettsiales, Enterobacteriales, Burkholderiales, Vibrionales, Actinomycetales, Gallionellales and Nitrosomonadales. In contrast, dominant orders of bacterioplankton at all five sites included Prochlorales, SAR-11 clade, Rhodobacterales and Flavobacteriales. Canonical correspondence analysis (CCA) for 19 dominate orders of IMs revealed associations with environmental variables revealed and sites. Only 32 OTUs were in common to all IMs, but 21 of these OTUs were also in the bacterioplankton. About half of all OTUs of any pooled IM were also in the bacterioplankton at that site. The association of particular sites and 19 dominant orders with environmental variables was explored by canonical correspondence analysis. The influence of greater salinity was observed at site SP2 and on Vibrionales and Gallionellales. Greater chlorophyll at site MF was associated with Alteromonadales and Sphingomonadales. Lower DO, pH and salinity at site SP was associated with Cytophagales, Nostocales, and Oscillatoriales. The ten most abundant OTUs per pooled IM accounted for 21% to 41% of sequence reads but only nine of these OTUs were most abundance in two pooled IMs. Six of ten most abundant OTUs from SP were also found in the bacterioplankton, suggesting this site has a greater influence from its surrounding bacterioplankton. It may be that the poor environmental conditions at site SP, and to a lesser extend KL, stressed the fish and led to dysbiosis involving colonization by surrounding bacterioplankton. Overall, the large variability within and among IMs of M. cephalus populations is only partly explained by ambient bacterioplankton community composition and stressful environmental variables. The establishment of host-commensal relationships earlier in the life history and genotypic differences of individuals can also be contributing to IM variability of M. cephalus.
TOPICAL NAME USED AS SUBJECT
Ecology; Microbiology; Environmental science
UNCONTROLLED SUBJECT TERMS
Subject Term
Biological sciences;Health and environmental sciences