Genomic investigations of acute munitions exposures on the health and skin microbiome composition of leopard frog (Rana pipiens) tadpoles

From BugSigDB
Reviewed Marked as Reviewed by ChiomaBlessing on 2024-3-13
study design
Citation
PMID PubMed identifier for scientific articles.
DOI Digital object identifier for electronic documents.
URI
Authors
Gust KA, Indest KJ, Lotufo G, Everman SJ, Jung CM, Ballentine ML, Hoke AV, Sowe B, Gautam A, Hammamieh R, Ji Q, Barker ND
Journal
Environmental research
Year
2021
Keywords:
Amphibian health, Amphibian skin microbiome, Aquatic ecotoxicology, Munitions constituents, Transcript expression
Natural communities of microbes inhabiting amphibian skin, the skin microbiome, are critical to supporting amphibian health and disease resistance. To enable the pro-active health assessment and management of amphibians on Army installations and beyond, we investigated the effects of acute (96h) munitions exposures to Rana pipiens (leopard frog) tadpoles and the associated skin microbiome, integrated with RNAseq-based transcriptomic responses in the tadpole host. Tadpoles were exposed to the legacy munition 2,4,6-trinitrotoluene (TNT), the new insensitive munition (IM) formulation, IMX-101, and the IM constituents nitroguinidine (NQ) and 1-methyl-3-nitroguanidine (MeNQ). The 96h LC50 values and 95% confidence intervals were 2.6 (2.4, 2.8) for ΣTNT and 68.2 (62.9, 73.9) for IMX-101, respectively. The NQ and MeNQ exposures caused no significant impacts on survival in 96h exposures even at maximum exposure levels of 3560 and 5285 mg/L, respectively. However, NQ and MeNQ, as well as TNT and IMX-101 exposures, all elicited changes in the tadpole skin microbiome profile, as evidenced by significantly increased relative proportions of the Proteobacteria with increasing exposure concentrations, and significantly decreased alpha-diversity in the NQ exposure. The potential for direct effects of munitions exposure on the skin microbiome were observed including increased abundance of munitions-tolerant phylogenetic groups, in addition to possible indirect effects on microbial flora where transcriptional responses suggestive of changes in skin mucus-layer properties, antimicrobial peptide production, and innate immune factors were observed in the tadpole host. Additional insights into the tadpole host's transcriptional response to munitions exposures indicated that TNT and IMX-101 exposures significantly enriched transcriptional expression within type-I and type-II xenobiotic metabolism pathways, where dose-responsive increases in expression were observed. Significant enrichment and increased transcriptional expression of heme and iron binding functions in the TNT exposures served as likely indicators of known mechanisms of TNT toxicity including hemolytic anemia and methemoglobinemia. The significant enrichment and dose-responsive decrease in transcriptional expression of cell cycle pathways in the IMX-101 exposures was consistent with previous observations in fish, while significant enrichment of immune-related function in response to NQ exposure were consistent with potential immune suppression at the highest NQ exposure concentration. Finally, the MeNQ exposures elicited significantly decreased transcriptional expression of keratin 16, type I, a gene likely involved in keratinization processes in amphibian skin. Overall, munitions showed the potential to alter tadpole skin microbiome composition and affect transcriptional profiles in the amphibian host, some suggestive of potential impacts on host health and immune status relevant to disease susceptibility.

Experiment 3


Reviewed Marked as Reviewed by ChiomaBlessing on 2024-3-13

Curated date: 2024/03/07

Curator: Victoria

Revision editor(s): Victoria, ChiomaBlessing

Differences from previous experiment shown

Subjects

Location of subjects
United States of America
Host species Species from which microbiome was sampled. Contact us to have more species added.
Rana pipiens
Body site Anatomical site where microbial samples were extracted from according to the Uber Anatomy Ontology
Tadpole Tadpole stage,Tadpole,tadpole
Condition The experimental condition / phenotype studied according to the Experimental Factor Ontology
Environmental exposure measurement Environmental exposure measurement,environmental exposure measurement
Group 0 name Corresponds to the control (unexposed) group for case-control studies
Control group
Group 1 name Corresponds to the case (exposed) group for case-control studies
Tadpoles exposed to 3560 mg/L Nitroguanidine (NQ)
Group 1 definition Diagnostic criteria applied to define the specific condition / phenotype represented in the case (exposed) group
Tadpoles were exposed to the concentration of 3560 mg/L of Nitroguanidine (NQ) for 96 hours.
Group 0 sample size Number of subjects in the control (unexposed) group
4
Group 1 sample size Number of subjects in the case (exposed) group
4
Antibiotics exclusion Number of days without antibiotics usage (if applicable) and other antibiotics-related criteria used to exclude participants (if any)
None

Lab analysis

Sequencing type
16S
16S variable region One or more hypervariable region(s) of the bacterial 16S gene
V4
Sequencing platform Manufacturer and experimental platform used for quantifying microbial abundance
Illumina

Statistical Analysis

Data transformation Data transformation applied to microbial abundance measurements prior to differential abundance testing (if any).
relative abundances
Statistical test
LEfSe
Significance threshold p-value or FDR threshold used for differential abundance testing (if any)
0.05
MHT correction Have statistical tests be corrected for multiple hypothesis testing (MHT)?
Yes
LDA Score above Threshold for the linear discriminant analysis (LDA) score for studies using the popular LEfSe tool
2

Alpha Diversity

Faith Phylogenetic diversity, takes into account phylogenetic distance of all taxa identified in a sample
decreased

Signature 1

Reviewed Marked as Reviewed by ChiomaBlessing on 2024-3-13

Curated date: 2024/03/07

Curator: Victoria

Revision editor(s): Victoria, ChiomaBlessing

Source: Figure 6

Description: LEfSe-identified significant taxa in the NQ exposed group compared to the control group

Abundance in Group 1: increased abundance in Tadpoles exposed to 3560 mg/L Nitroguanidine (NQ)

NCBI Quality ControlLinks
Aeromonadaceae
Aeromonadales
Comamonadaceae
Gammaproteobacteria
Pseudomonadaceae
Shewanellaceae

Revision editor(s): Victoria, ChiomaBlessing

Signature 2

Reviewed Marked as Reviewed by ChiomaBlessing on 2024-3-13

Curated date: 2024/03/07

Curator: Victoria

Revision editor(s): Victoria, ChiomaBlessing

Source: Figure 6

Description: LEfSe-identified significant taxa in the NQ exposed group compared to the control group

Abundance in Group 1: decreased abundance in Tadpoles exposed to 3560 mg/L Nitroguanidine (NQ)

NCBI Quality ControlLinks
Acidobacteriota
Actinomycetota
Alphaproteobacteria
Bacillaceae
Bacillales
Bacilli
Bacillota
Bryobacterales
Burkholderiales
Chloroflexota
Chthoniobacteraceae
Hyphomicrobiaceae
Hyphomicrobiales
Oxalobacteraceae
Planctomycetota
Rhodospirillales
Solibacteraceae
Spartobacteria
Sphingomonadaceae
Sphingomonadales
Terriglobales
Terriglobia
Thermoleophilia
Verrucomicrobiota
Chthoniobacterales
Burkholderiaceae

Revision editor(s): Victoria, ChiomaBlessing