A review on comparative mechanistic studies of antimicrobial peptides against archaea

Abstract

Archaea was until recently considered as a third domain of life in addition to bacteria and eukarya but recent studies support the existence of only two superphyla (bacteria and archaea). The fundamental differences between archaeal, bacterial, and eukaryal cells are probably the main reasons for the comparatively lower susceptibility of archaeal strains to current antimicrobial agents. The possible emerging pathogenicity of archaea and the role of archaeal methanogens in methane emissions, a potent greenhouse gas, has led many researchers to examine the sensitivity patterns of archaea and make attempts to find agents that have significant anti-archaeal activity. Even though antimicrobial peptides (AMPs) are well known with several published reviews concerning their mode of action against bacteria and eukarya, to our knowledge, to date no reviews are available that focus on the action of these peptides against archaea. Herein, we present a review on all the peptides that have been tested against archaea. In addition, in an attempt to shed more light on possible future work that needs to be performed we have included a brief overview of the chemical characteristics, spectrum of activity, and the known mechanism of action of each of these peptides against bacteria and/or fungi. We also discuss the nature of and key physiological differences between Archaea, Bacteria, and Eukarya that are relevant to the development of anti-archaeal peptides. Despite our relatively limited knowledge about archaea, available data suggest that AMPs have an even broader spectrum of activity than currently recognized.

Use of Lactic Acid Bacteria to Reduce Methane Production in Ruminants, a Critical Review

“…Cultivated members of both of these methanogen clades are hydrogenotrophic and use H 2 and CO 2 for CH 4 formation. Their cell walls contain pseudomurein and have similarities to those found in Gram positive bacteria which may be relevant to their sensitivity to antimicrobial agents (Varnava et al, 2017). Other significant members of the methanogen community in the rumen are methylotrophs, producing CH 4 from methyl-containing substrates, particularly methylamines and methanol.…”

“…The idea that LAB can be used to reduce CH 4 production in ruminant livestock is not new. Reviews of CH 4 mitigation strategies consistently refer to this possibility (Hristov et al, 2013; Takahashi, 2013; Jeyanathan et al, 2014; Knapp et al, 2014; Varnava et al, 2017). However, research on the topic has been limited and convincing data from animal trials to support this concept are lacking.…”

“…New technical mitigation options are needed. Reviews of CH 4 mitigation strategies consistently discuss the possibility that lactic acid bacteria (LAB) could be used to modulate rumen microbial communities thus providing a practical and effective on-farm approach to reducing CH 4 emissions from ruminant livestock (Hristov et al, 2013; Takahashi, 2013; Knapp et al, 2014; Jeyanathan et al, 2014; Varnava et al, 2017). This review examines the possible contribution of LAB in the development of an on-farm CH 4 mitigating strategy.…”

Regulation of lipid peroxidation and ferroptosis in diverse species

“…In archaea, this is achieved mainly through alterations of monounsaturated diethers, isoprenoid hydroxylation, and the tetraether:diether ratio. In bacteria, distinct targets of lipid-based adaptation include mainly variable contents of monounsaturated, short chain, and branched chain fatty acids (Suutari and Laakso 1994;Siliakus et al 2017;Varnava et al 2017). These saturated and monounsaturated lipids, common for many species of archaea in different habitats, including microbiomes in animals and humans, are not readily oxidized at moderate temperatures ("normal" for higher organisms), whereas lipids in thermophilic archaea organisms may get oxidized at "normal" (for them) temperatures up to 122°C (Takai et al 2000;Quince et al 2017).…”

Overview of Host Defense Peptides and Their Applications for Plastic and Reconstructive Surgeons

“…Original descriptions referred to these compounds as "antimicrobial peptides" or "AMP's" based on the theory that their principal purpose was the direct eradication of bacterial species. However, recent studies have revealed that host defense peptides are capable of eliminating bacteria, viruses, parasites, and even archaea 4,5 and these peptides have displayed critical functions in immunomodulation and wound healing that may actually be more important than their direct actions against infectious agents. 6,7 Structurally and mechanistically, host defense peptides are a diverse class of molecules that can be synthesized through a multi-enzymatic process or ribosomal translation, with or without post-translational modification.…”