Fourier-transformed infrared spectroscopy: a tool to identify gross chemical changes from healthy to yellow band disease tissues

Abstract

Yellow band disease (YBD) is a common and wide-spread Caribbean syndrome that affects the genus Orbicella, a group of species that constitute the framework of Caribbean coral reefs. Previous studies have shown that the structure and function of bacterial assemblages vary between healthy tissues and YBD lesions; however, how the molecular composition of tissues varies as tissues transition from healthy to YBD has not been determined before. The present study provides the first survey of macromolecules found from healthy (H), apparently healthy (AH), transition (TR) and YBD tissues of Orbicella faveolata. For this, we used Fourier-transformed mid-infrared spectroscopy (FTIR) to compare absorption profiles as a proxy for the gross molecular composition of decalcified H, AH and YBD tissues. We found a significantly higher level of infrared absorption for bands assigned to lipids in H tissues compared to YBD tissues, suggesting that lipid compounds are more abundant in compromised tissues in relation to other macromolecules. We also found a lower level of intensity of bands assigned to carbohydrates and proteins in YBD tissues, compared to H and AH tissues. A similar pattern was observed for phospholipidic compounds in relation to fatty acids. This study is the first to show that healthy and YBD-compromised tissues have different infrared absorption profiles, suggesting that alterations in the biochemical composition occur during pathogenesis. Future studies should focus on determining the actual concentration of these compounds in H, AH, TR and YBD tissues and on testing the role of translocation of photoassimilates from H tissues and/or from endolithic algae to YBD tissues. KEY WORDS: Coral diseases · Yellow band disease · Infrared spectroscopy · Tissue composition Resale or republication not permitted without written consent of the publisherDis Aquat Org 107: [249][250][251][252][253][254][255][256][257][258] 2014 Among the diseases described from the Caribbean (Green & Bruckner 2000), yellow band (YBD) is arguably the one with the largest detrimental and longest lasting effects for coral reef health in the region (Cróquer et al. 2012). This syndrome tends to be persistent (Bruckner & Bruckner 2006), and it affects all species in the genera Orbicella and Montastraea e.g. O. annularis, O. faveolata, O. franksi and M. cavernosa), which are the dominant reef-building corals in the region (for specific examples, see Cortés 2003). Furthermore, YBD compromises the fecundity of M. faveolata ), produces significant mortality on larger colonies and has contributed to an overall reduction of live coral cover (Bruckner & Bruckner 2006) over the past decades. Combined, these impacts significantly affect the population size of Orbicella species, and therefore, it has been hypothesized that YBD alone might reduce reef complexity throughout the Caribbean (Bruckner & Bruckner 2006). While other Caribbean diseases such as white plague, white band, white pox and patchy necrosis may reduce coral cover rapidly, infected...

Caribbean yellow band disease compromises the activity of catalase and glutathione S-transferase in the reef-building coral Orbicella faveolata exposed to anthracene

“…Thus, it is conceivable that anthracene could be inducing damage to the zooxanthellae associated with healthy and diseased O. faveolata, compromising the enzymatic responses or reducing its synthesis in both healthy and CYBDaffected tissues exposed to high doses of this PAH. Such compromise is worse in CYBD-affected tissues because of the additional stress this pathology imposes not only for the zooxanthellae, but also for the coral holobiont (Mydlarz et al 2009, Guerra et al 2014, Morgan et al 2015. This hypothesis, along with the underlying cellular mechanisms involved, remains to be formally tested.…”

“…This disease produces rapid and extensive mortality of living tissues of its hosts, but more importantly, reduces fecundity ), causes structural damage and energetically compromises the zooxanthellae (Cervino et al 2001, Morgan et al 2015. It also alters the gross composition of tissues by decreasing the ratio of proteins and carbohydrates in relation to the amount of lipids in CYBD lesions (Guerra et al 2014). The etiology of CYBD has been associated with 3 different strains of Vibrio (Cervino et al 2008, Weil et al 2008.…”

Disentangling causation: complex roles of coral‐associated microorganisms in disease

“…2). These changes result in shifts within the holobiont relative to the apparently healthy state, and are linked to reduced host coral growth and survivorship, as well as disease occurrences (Guerra et al, 2014;Ritchie, 2006;Teplitski et al, 2016;Zaneveld et al, 2016). The importance of the changes in microbial communities for host health and stability plus ecosystem resilience have been well studied in other systems such as agriculture and terrestrial soils, although less understood in the marine and coral reef context (Ainsworth et al, 2010;Bakker et al, 2012;Balser et al, 2006;Verbruggen et al, 2012).…”

Testing methods to mitigate Caribbean yellow-band disease on Orbicella faveolata

“…Caribbean yellow-band disease significantly and severely reduces reproductive output in O. faveolata through several mechanisms, including: (i) the direct reduction of live tissue, (ii) the reduction in fecundity of affected polyps and polyps adjacent to the lesion margin, and (iii) fragmentation of large tissue patches resulting in more tissue “edges” that are non-reproductive, and fewer large and reproductive ramets ( Weil, Cróquer & Urreiztieta, 2009 ). Recent evidence gathered through infrared spectroscopy indicates that energy-rich proteins, carbohydrates, and phospholipidic compounds are reduced in diseased and marginal tissue, presumably leaving less energy for reproduction ( Guerra et al, 2014 ). In addition, evidence suggests that CYBD disproportionately affects the largest (>1 m 2 ) colonies in a population.…”