Real-time PCR assay for Aquimarina macrocephali subsp. homaria and its distribution in shell disease lesions of Homarus americanus, Milne-Edwards, 1837, and environmental samples

Abstract

Epizootic shell disease (ESD) is causing major losses to the lobster fishery in southern New England. Potential pathogens have been identified in lesion communities, but there are currently no efficient means of detecting and quantifying their presence. A qPCR assay was developed for a key potential pathogen, Aquimarina macrocephali subsp. homaria found to be ubiquitous in ESD lesions but not the unaffected integument. Application of the assay to various samples demonstrated that A. macrocephali subsp. homaria is ubiquitous and abundant in lobster lesions, commonly associated with healthy surfaces of crabs and is scarce in water and sediment samples from southern New England suggesting the affinity of this microorganism to the Arthropod integument. The qPCR assay developed here can be applied in future in vivo and in vitro studies to better understand the ecology and role of A. macrocephali subsp.homaria. in shell disease.

Water temperature and disease alters bacterial diversity and cultivability from American lobster (Homarus americanus) shells

“…There were several bacterial taxa from the sequencing data that were associated with ESD progression or absence in this study, which have been identified in previous studies, e.g., 30 , 35 , 53 which noted that many of these taxa were present in healthy and visibly diseased lobsters in different amounts. In our samples, Aquimarina , which has long been implicated as a commensal-turned-pathogen in ESD, 32 , 33 increased in abundance in lobsters with lesions >11% of the shell (Index levels 2 and 3). We identified Rubritalea in the bacterial community data as abundant in healthy lobsters and reduced in those with ESD.…”

“… 20 Culture-dependent and culture-independent bacterial investigations have been performed on shell-diseased lobsters and shown that the etiology of the disease is complex, likely involving multiple bacterial species in the Alteromonadaceae, Flavobacteriaceae, Pseudomonadaceae, Rhodobacteraceae, and Vibrionaceae families. 27 , 28 , 29 , 30 Particular focus has been placed on two microbial genera consistently associated with ESD, Aquimarina and Thalassobius species, 29 , 31 , 32 but the role of these bacteria in disease lesions remain unclear whether they are infectious agents, 33 were commensally present an induced due to pathogenicity, 34 or if they are making use of a niche and contributing to the poly-microbial community which accumulates in lesions. 35 A dysbiotic shift in the shell microbial community resulting from environmental stressors has been suggested.…”

Warmer water temperature and epizootic shell disease reduces diversity but increases cultivability of bacteria on the shells of American Lobster (Homarus americanus)

“…There were several bacterial taxa from the sequencing data which were associated with ESD progression or absence in this study, which have been identified in previous studies, e.g., (Feinman et al, 2017; Meres et al, 2012; Whitten et al, 2014) which noted that many of these taxa were present in healthy and visibly-diseased lobsters in different amounts. In our samples, Aquimarina , which has long been implicated as a commensal-turned-pathogen in ESD (Quinn et al, 2017, 2012), increased in abundance in lobsters with lesions >11% of the shell (Index levels 2 and 3). We identified Rubritalea in the bacterial community data as abundant in healthy lobsters and reduced in those with ESD.…”

“…Culture-dependent and culture-independent bacterial investigations have been performed on shell-diseased lobsters and shown that the etiology of the disease is complex, likely involving multiple bacterial species in the Alteromonadaceae, Flavobacteriaceae, Pseudomonadaceae, Rhodobacteraceae and Vibrionaceae families (Bell et al, 2012; Chistoserdov et al, 2012, 2005; Meres et al, 2012). Particular focus has been placed on two microbial genera consistently associated with ESD, Aquimarina and Thalassobius species (Chistoserdov et al, 2012; Quinn et al, 2017, 2013), but a true etiology has yet to be defined. In fact, the role of these bacteria in disease lesions remain unclear and a dysbiotic shift in the shell microbial community resulting from environmental stressors has been suggested (Feinman et al, 2017; Ishaq et al, 2022; Meres et al, 2012).…”

High Potential for Secondary Metabolite Production of Paracoccus marcusii CP157, Isolated From the Crustacean Cancer pagurus

“…Aquimarina spp. are known chitin-degraders and presumed to play a role in disease progression or even development ( Xu et al, 2015 ; Quinn et al, 2017 ). We assume that CP157, which is not able to degrade chitin or its monomer N -acetylglucosamine itself, benefits from the progressing penetration of the exoskeleton by Aquimarina spp.…”