An observational study of the microbiome of the maternal pouch and saliva of the tammar wallaby, Macropus eugenii, and of the gastrointestinal tract of the pouch young

Abstract

An observational study of the microbiome of the maternal pouch and saliva of the tammar wallaby, Macropus eugenii, and of the gastrointestinal tract of the pouch young Marsupial mammals, born in an extremely atricial state with no functional immune system, offer a unique opportunity to investigate both the developing microbiome and its relationship to that of the mother and the potential influence of this microbiome upon the development of the immune system. In this study we used a well-established marsupial model animal, Macropus eugenii, the tammar wallaby, to document the microbiome of three related sites: the maternal pouch and saliva, and the gastrointestinal tract (GIT) of the young animal. We used molecular-based methods, targeting the 16S rDNA gene to determine the bacterial diversity at these study sites.In the maternal pouch, 41 unique phylotypes, predominantly belonging to the phylum Actinobacteria, were detected, while in the saliva, 48 unique phylotypes were found that predominantly belonged to the phylum Proteobacteria. The GIT of the pouch young had a complex microbiome of 53 unique phylotypes, even though the pouch young were still permanently attached to the teat and had only been exposed to the external environment for a few minutes immediately after birth while making their way from the birth canal to the maternal pouch. Of these 53 phylotypes, only nine were detected at maternal sites. Overall, the majority of bacteria isolated were novel species (,97 % identity to known 16S rDNA sequences), and each study site (i.e. maternal pouch and saliva, and the GIT of the pouch young) possessed its own unique microbiome. INTRODUCTIONMetatherian mammals or marsupials are characterized by short gestation periods ranging from only 11 days in the stripe-faced dunnart, Sminthopsis macroura (Renfree, 2006), to 35 days in the koala, Phascolartos cinereus (Tyndale- Biscoe & Renfree, 1987). At birth, many of the major body systems, including the immune system, are immature, yet the young animal has well-developed forelimbs, mouth and tongue, features which allow it to make its way from the birth canal and into the maternal pouch. Here the young animal attaches itself to a teat and subsequently undergoes the major processes of development and maturation ( Fig. 1) (Tyndale-Biscoe & Janssen, 1988;Tyndale-Biscoe, 2005).Despite an immature immune system, the pouch young is able to survive in the pouch environment, which is known to contain a range of micro-organisms (Deakin & Cooper, 2004;Old & Deane, 1998). It has been presumed that aAbbreviations: ARDRA, amplified rDNA restriction analysis; GIT, gastrointestinal tract.The GenBank/EMBL/DDBJ accession numbers for the 16S rDNA phylotype sequences determined in this study are GQ358790-GQ358918.Three supplementary tables, showing phylotypes found in the pouch of three tammar wallabies and their closest identity to 16S rDNA sequences in GenBank, phylotypes found in the saliva of three adult tammar wallabies and their closest 16S rDNA identity to 16S rDNA sequences in Ge...

Canibacter oris gen. nov., sp. nov., isolated from an infected human wound

“…In addition, Leifsonia aquatica has been recovered from bite wounds caused by dogs and cats (Abrahamian & Goldstein, 2011). Furtheremore, Zimmermannella bifida and Leucobacter chromiireducens were identified among taxa cloned from the saliva of tammar wallabies (Chhour et al, 2010). The family Microbacteriaceae embraces a large group of Grampositive bacteria that are distinguished from all families of the order Actinomycetales by their unusual B group cellwall peptidoglycan and unsaturated respiratory menaquinones (Evtushenko, 2012).…”

Marsupial oral cavity microbiome

“…A study of the tammar wallaby pouch young suggested factors that protect young animals against potentially pathogenic microbial infections could include the microbiome from the maternal saliva 20 . The microbiomes of the pouch and saliva from the mother were compared with the gastrointestinal tract (GIT) microbiome of the pouch young using 16S rRNA gene comparative methods.…”

“…The microbiomes of the pouch and saliva from the mother were compared with the gastrointestinal tract (GIT) microbiome of the pouch young using 16S rRNA gene comparative methods. Each study site had a unique microbiome 20 . The maternal pouch harboured 41 unique Actinobacteria phylotypes, while in the saliva there were 48 unique Proteobacteria phylotypes.…”

“…The GIT of the pouch young had a complex microbiome of 53 unique phylotypes and of these, only nine were detected at either maternal site. Overall, the majority of bacteria detected were novel species and each study site possessed its own unique microbiome 20 .…”

Physical Mapping of Innate Immune Genes, Mucins and Lysozymes, and Other Non-Mucin Proteins in the Tammar Wallaby <i>(Macropus eugenii)</i>

“…Marsupials are unable to mount a functional adaptive immune response until several weeks into their pouch life, as they are born with undeveloped immune tissue [Yadav et al, 1972;Cutts and Krause, 1982;Basden et al, 1997] and have insufficient numbers of mature lymphocytes [Coutinho et al, 1995;Old and Deane, 2003;Old et al, 2004]. The delayed development of their adaptive immune response is intriguing, as marsupial young are born into a nonsterile environment containing a range of potentially pathogenic bacteria [Osawa et al, 1992;Old and Deane, 1998;Deakin and Cooper, 2004;Chhour et al, 2010], yet they manage to survive while their immune tissues continue to mature. Determining how these altricial young are immunologically protected is of great interest, which has led to studies of the maternal contribution to both pre-and postnatal protection through such mechanisms as maternal milk Demmer, 1999, 2000;Joss et al, 2007Joss et al, , 2009 and pouch secretions [Ambatipudi et al, 2007[Ambatipudi et al, , 2008.…”