Microwave-accelerated processing of coral tissue histology

Abstract

Background: Microwave technology has revolutionized histological processing by reducing processing time and improving tissue integrity. We describe the first microwave-accelerated tissue processing procedure for healthy and diseased tissue fragments of two species of corals: the gorgonian Gorgonia ventalina and the scleractinian Acropora cervicornis. Methods: Fourteen tissue samples from sea fans (eleven healthy and three diseased), and one tissue sample from a healthy A. cervicornis, were decalcified and processed using microwaves. Histological slices were stained using hematoxylin and eosin and immunostained using an antibody against Aspergillus. Results: By using microwave technology, the decalcification time, as well as the steps and time for tissue processing were significantly reduced while maintaining the integrity of the tissue. Conclusions: This technique accelerates the chemical processing of coral tissue, while providing high quality and optimal resolution of histological sections.

Complementary sampling methods for coral histology, metabolomics and microbiome

“…Both samples from diseased fragment should include a portion of the disease lesion border sequencing used to classify 16S ribosomal DNA has known limitations and requires careful application of standardization or rarefaction procedures to meet the needs of research questions without imparting unintended bias (Bolyen et al, 2019;Caporaso et al, 2012). For example, while preservation of coral in PFA allows fragments to be used for both histology and microbial analyses, this technique may also cause underestimation of mucus-borne taxa (van Oppen & Blackall, 2019 At present, histology can be time-consuming and requires specialized equipment and expertise, though these constraints have been reduced recently (Toledo-Hernández et al, 2014). A valuable standalone tool to describe coral health (Work & Meteyer, 2014), histology also provides critical context to clarify microbial and metabolomic findings (Sogin et al, 2016;Work & Meteyer, 2014).…”

“…Histology of fixed coral tissue is a 'gold standard' for assessing coral condition by providing evidence of coral tissue integrity and cell structure and for allowing for the characterization of apoptosis, necrosis, tissue thickness, presence of microorganisms and algal symbiont characteristics (Gierz, Ainsworth, & Leggat, 2020;McClanahan et al, 2004;Work & Meteyer, 2014). Technological advances now allow histological assays to be processed quickly and in large quantities (Toledo-Hernández, Torres-Vázquez, & Serrano-Vélez, 2014). The bacterial coral microbiome appears highly significant to coral health from larval to adult stages, and dysbiosis of the coral holobiont has been implicated in both disease and bleaching events (Ainsworth & Gates, 2016;Ainsworth, Thurber, & Gates, 2010;Bourne, Morrow, & Webster, 2016;Casey, Connolly, & Ainsworth, 2015;Hernandez-Agreda, Leggat, Bongaerts, & Ainsworth, 2016;Hernandez-Agreda, Leggat, Bongaerts, Leggat, Bongaerts, Herrera, & Ainsworth, 2018;Meyer et al, 2019;Pollock et al, 2019;Sweet & Bulling, 2017;van Oppen & Blackall, 2019).…”