Gut microbiome–immune system interaction in reptiles

Abstract

Reptiles are ectothermic amniotes in a world dominated by endotherms. Reptiles originated more than 300 million years ago and they often dwell in polluted environments which may expose them to pathogenic micro-organisms, radiation and/or heavy metals. Reptiles also possess greater longevity and may live much longer than similar-sized land mammals, for example, turtles, tortoises, crocodiles and tuatara are long-lived reptiles living up to 100 years or more. Many recent studies have emphasized the pivotal role of the gut microbiome on its host; thus, we postulated that reptilian gut microbiome and/or its metabolites and the interplay with their robust immune system may contribute to their longevity and overall hardiness. Herein, we discuss the composition of the reptilian gut microbiome, immune system-gut microbiome cross-talk, antimicrobial peptides, reptilian resistance to infectious diseases and cancer, ageing, as well the current knowledge of the genome and epigenome of these remarkable species. Preliminary studies have demonstrated that microbial gut flora of reptiles such as crocodiles, tortoises, water monitor lizard and python exhibit remarkable anticancer and antibacterial properties, as well as comprise novel gut bacterial metabolites and antimicrobial peptides. The underlying mechanisms between the gut microbiome and the immune system may hold clues to developing new therapies overall for health, and possible extrapolation to exploit the ancient defence systems of reptiles for Homo sapiens benefit.

Mass Spectrometric Analysis of Bioactive Conditioned Media of Bacteria Isolated From Reptilian Gut

“…Similarly, bacteria present in the insect gut produces bioactive molecules that stimulate the insect immunity against the pathogenic invaders [ 37 ]. All these examples show that bacteria isolated from interesting species may be a source of potential innovative resource for antibacterial agents [ 10 ].…”

“…Moreover, bacterial conditioned media were prepared using RPMI-1640, and the composition of RPMI-1640 include several different compounds (such as: aspartic acid; glutamic acid; asparagine; serine; glutamine; histidine; glycine; threonine; arginine; alanine; tyrosine; cystine; valine; methionine; norvaline; tryptophan; phenylalanine; isoleucine; leucine; lysine) which could interfere with our findings, hence, our results should be interpreted in view of RPMI composition. Nonetheless, in depth analysis and characterization of these innovative metabolites is warranted and these should be tested further in vitro and in vivo as well as animal models with a defined microbiota such as gnotobiotic mice [ 10 ]. This will facilitate comprehension of their precise role, interaction with each other as well as with the immune system and assess their prospective use as pre/post/antibiotics for the benefit of human health.…”

“…Previous research as used bacteria/yeast of soil origin as a source for antibiotics but the bacteria of GI tract of animals inhabiting unhygienic environments offer an important bacterial flora that ought to be explored for potentially novel antimicrobials [ 10 ]. Microbes have remained a valuable resource for early-stage antibiotic discovery, producing innumerable useful secondary metabolites and other bioactive compounds [ 17 ].…”

16S rRNA gene‐based meta‐analysis of the reptile gut microbiota reveals environmental effects, host influences and a limited core microbiota

“…As with other vertebrate taxa, the reptile gut microbiota is likely to play many important roles, including in host digestion (Hanning & Diaz‐Sanchez, 2015; McFall‐Ngai et al, 2013; Tremaroli & Bäckhed, 2012; Turnbaugh et al, 2006). Gut microbes are crucial to breaking down complex molecules into digestible components for vertebrate hosts, as well as priming the immune system (Kau et al, 2011; Siddiqui et al, 2022) and defending against potential pathogens by occupying gut niches (Walter & Ley, 2011). Yet another role may be in reproduction, as demonstrated for a wealth of wild species, including reptiles (Comizzoli et al, 2021).…”

“…. Gut microbes are crucial to breaking down complex molecules into digestible components for vertebrate hosts, as well as priming the immune system (Kau et al, 2011;Siddiqui et al, 2022) and defending against potential pathogens by occupying gut niches (Walter & Ley, 2011). Yet another role may be in reproduction, as demonstrated for a wealth of wild species, including reptiles (Comizzoli et al, 2021).…”