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NCSU

Department of Entomology and Plant Pathology
College of Agricultural and Life Sciences

Welcome to the Mikaelyan lab at NCSU!

Insect-microbiome dynamics

Our lab works at the interface of entomology and microbial ecology to uncover patterns of coevolution between insects and their microbiomes, and to better understand the role of the microbiome in insect biology. Our work is concentrated around both pests and beneficial insects that feed on lignocellulose, including beetles, cockroaches and termites.

THE MIKAELYAN LAB

We are a small team of like-minded scientists that are passionate about both entomology and microbiology. We are highly collaborative, both within and between departments at NC State. We also have active collaborations with several researchers overseas.

Assistant Professor and
Principal Investigator

Melbert Schwarz

Graduate researcher

if you are a science ninja and want to join us!

OUR RESEARCH

Insects are among the oldest organisms to have walked the earth. In the last 400 million years of their existence, they have amassed unique adaptations, diversified into countless species, and colonized virtually every available ecological niche. They owe their evolutionary success and ecological impact at least in part to the complex symbioses they have forged with the microbial world

Our lab works at the interface of entomology and microbial ecology to uncover patterns of coevolution between insects and their microbiomes, and to better understand the role of the microbiome in insect biology. Our primary focus is on insects feeding on dead plant material, such as wood or litter, but are easily distracted by cool questions concerning other insects :).

Insects display a diversity of symbioses that is unmatched in the animal world, ranging from obligate intracellular endosymbiosis to intestinal microbiomes. While only some insect species possess these endosymbionts (e.g., Buchnera or Blattabacterium), all insect species are associated with complex communities of microbes in their guts, also called gut microbiomes.

Studies have shown that insects are colonized by host-specific microbiomes, and that the taxonomic composition reflects the evolutionary history of the hosts. 

Mobirise
Mobirise

Our lab uses a combination of classical microbiology, molecular ecology, high-throughput sequencing, and entomology to study the coevolution of microbiomes with wood- and litter-feeding insects. These insects play essential roles in the turnover of lignocellulose in terrestrial ecosystems, but many species have gained notoriety as pests. Regardless, of whether they are beneficial insects or pests, several species have evolved to digest lignocellulose with the aid of their microbiomes

Lignocellulose is the major structural component of plant cell walls, and is relatively recalcitrant to biochemical attack. So the few insect groups among the beetles and cockroaches that thrive on lignocellulose, have evolved symbiotic mechanisms to digest it.

Termites are exemplars of symbiotic digestion, especially of lignocellulose. They are essentially eusocial, morphologically reduced cockroaches, that evolved 150 million years ago from more primitive, and potentially detritivorous, cockroaches. Many termite species have diversified to feed on lignocellulose in different stages of decay, ranging from sound wood through litter, and humus. Their gut microbiomes are not only complex, but also unique in their composition; many of the bacterial and protozoan lineages found in these communities have only distant relatives in other environments. 

Symbiotic digestion of lignocellulose involves the efficient breakdown of lignocellulose through a combination of mechanical and enzymatic action - the latter involves contributions from both the host and the microbiome. Despite the relative wealth of knowledge that exists about the mechanism of symbiotic digestion in termites, very little is known about how lignocellulose digestion may have evolved in other cockroach lineages or beetles.  

One of the projects in the lab involves understanding the mechanism of symbiotic digestion of lignocellulose in insects feeding on dead wood and litter. We are primarily interested in identifying the symbionts involved in the digestion of different components of lignocellulose, and in the forces driving parallel evolution between these insects and their microbiomes.  

Mobirise
Mobirise

The evolution of symbiotic digestion of lignocellulose has been crucial to not just the ecological dominance of termites, but also their infamous success as major structural pests. Termites are responsible for over $5 billion dollars in annual damage. Therefore, a mechanistic understanding of the termite-microbiome symbiosis could be critical to the development of ecologically sustainable methods of pest control.

A project in this direction is aimed at understanding the degree to which insect digestionbehavior, vigor, and fitness is influenced by its microbiome. We use a combination of native and invasive species of termites for our experiments involving targeted alterations to the gut microbiome; these include Reticulitermes spp., Zootermopsis spp., and Nasutitermes spp. However, because termites cannot be raised germ-free, they cannot be used for experiments requiring finer control of microbiome composition; for such experiments, we use our gnotobiotic cockroach model based on Shelfordella lateralis

PUBLICATIONS

  1. Fiber-associated spirochetes are major agents of hemicellulose degradation in the hindgut of wood-feeding higher termites. (2018) G Tokuda, A Mikaelyan, C Fukui, Y Matsuura, H Watanabe, M Fujishima, ... Proceedings of the National Academy of Sciences  (Published online, 1810550115) 
  2. Gut microbial compositions mirror caste-specific diets in a major lineage of eusocial insects. (2018) S Otani, M Zhukova, NA Kone, RR da Costa, A Mikaelyan, P Sapountzis, ... bioRxiv, 418954
  3. Pycnoscelus surinamensis cockroach gut microbiota respond consistently to a fungal diet without mirroring those of fungus-farming termites . (2018) C Richards, S Otani, A Mikaelyan, M Poulsen. PloS one 12 (10), e0185745
  4. High‐resolution phylogenetic analysis of Endomicrobia reveals multiple acquisitions of endosymbiotic lineages by termite gut flagellates . (2017) A Mikaelyan, CL Thompson, K Meuser, H Zheng, P Rani, R Plarre, ... Environmental microbiology reports 9 (5), 477-483
  5. Microenvironmental heterogeneity of gut compartments drives bacterial community structure in wood-and humus-feeding higher termites . (2017) A Mikaelyan, K Meuser, A Brune. FEMS microbiology ecology 93 (1)
  6. Genome analysis of ‘Candidatus Ancillula trichonymphae’, first representative of a deep‐branching clade of Bifidobacteriales, strengthens evidence for convergent evolution in flagellate endosymbionts. (2016) JFH Strassert, A Mikaelyan, T Woyke, A Brune. Environmental microbiology reports 8 (5), 865-873
  7. Candidatus Adiutrix intracellularis’, an endosymbiont of termite gut flagellates, is the first representative of a deep‐branching clade of Deltaproteobacteria and a putative homoacetogen. (2016) W Ikeda‐Ohtsubo, JFH Strassert, T Köhler, A Mikaelyan, I Gregor, ... Environmental microbiology 18 (8), 2548-2564
  8. Age polyethism drives community structure of the bacterial gut microbiota in the fungus‐cultivating termite Odontotermes formosanus . (2016) H Li, C Dietrich, N Zhu, A Mikaelyan, B Ma, R Pi, Y Liu, M Yang, A Brune, ... Environmental microbiology 18 (5), 1440-1451
  9. The deterministic assembly of complex bacterial communities in germ-free cockroach guts . (2016) A Mikaelyan, CL Thompson, MJ Hofer, A Brune. Applied and environmental microbiology 82, 1256–1263
  10. Metagenomic analysis of the microbiota in the highly compartmented hindguts of six wood-or soil-feeding higher termites . (2015) K Rossmassler, C Dietrich, C Thompson, A Mikaelyan, JO Nonoh, ... Microbiome 3 (1), 56
  11. Classifying the bacterial gut microbiota of termites and cockroaches: a curated phylogenetic reference database (DictDb) . (2015) A Mikaelyan, T Köhler, N Lampert, J Rohland, H Boga, K Meuser, A Brune. Systematic and applied microbiology 38 (7), 472-482
  12. Diet is the primary determinant of bacterial community structure in the guts of higher termites . (2015) A Mikaelyan, C Dietrich, T Köhler, M Poulsen, D Sillam-Dussès, A Brune Molecular Ecology 24, 5284–5295
  13. Physicochemical conditions, metabolites, and community structure of the bacterial microbiota in the gut of wood-feeding cockroaches (Blaberidae: Panesthiinae). (2015) E Bauer, N Lampert, A Mikaelyan, T Köhler, K Maekawa, A Brune FEMS microbiology ecology 91, 1–14
  14. Analysis of midgut bacterial community structure of Neanthes chilkaensis from polluted mudflats of Gorai, Mumbai, India . (2014) AR Markande, A Mikaelyan, BB Nayak, KD Patel, NB Vachharajani, ... Advances in Microbiology 4 (13), 906
  15. Identifying the core microbial community in the gut of fungus‐growing termites . (2014) S Otani, A Mikaelyan, T Nobre, LH Hansen, NGA Koné, SJ Sørensen, ... Molecular ecology 23 (18), 4631-4644
  16. The fibre‐associated cellulolytic bacterial community in the hindgut of wood‐feeding higher termites (Nasutitermes spp.)  (2014) A Mikaelyan, JFH Strassert, G Tokuda, A Brune Environmental microbiology 16 (9), 2711-2722
  17. Immune-modulating gut symbionts are not “Candidatus Arthromitus”  (2013) CL Thompson, A Mikaelyan, A Brune. Mucosal immunology 6 (1), 200
  18. ‘Candidatus Arthromitus’ revised: segmented filamentous bacteria in arthropod guts are members of Lachnospiraceae. (2012) CL Thompson, R Vier, A Mikaelyan, T Wienemann, A Brune. Environmental microbiology 14 (6), 1454-1465


Address

Department of Entomology and Plant Pathology
3312 Gardner Hall, 100 Pilsbury Circle
North Carolina State University

Contacts

Email: amikael@ncsu.edu

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