Coral Probiotics: Premise, Promise, Prospects

The use of Beneficial Microorganisms for Corals (BMCs) has been proposed recently as a tool for the improvement of coral health, with knowledge in this research topic advancing rapidly. BMCs are defined as consortia of microorganisms that contribute to coral health through mechanisms that include ( a) promoting coral nutrition and growth, ( b) mitigating stress and impacts of toxic compounds, ( c) deterring pathogens, and ( d) benefiting early life-stage development. Here, we review the current proposed BMC approach and outline the studies that have proven its potential to increase coral resilience to stress. We revisit and expand the list of putative beneficial microorganisms associated with corals and their proposed mechanisms that facilitate improved host performance. Further, we discuss the caveats and bottlenecks affecting the efficacy of BMCs and close by focusing on the next steps to facilitate application at larger scales that can improve outcomes for corals and reefs globally. Expected final online publication date for the Annual Review of Animal Biosciences, Volume 9 is February 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Vitamin D deficiency serves as a precursor to stunted growth and central adiposity in zebrafish

Emerging evidence demonstrates the importance of sufficient vitamin D (1α, 25-dihydroxyvitamin D3) levels during early life stage development with deficiencies associated with long-term effects into adulthood. While vitamin D has traditionally been associated with mineral ion homeostasis, accumulating evidence suggests non-calcemic roles for vitamin D including metabolic homeostasis. In this study, we examined the hypothesis that vitamin D deficiency (VDD) during early life stage development precedes metabolic disruption. Three dietary cohorts of zebrafish were placed on engineered diets including a standard laboratory control diet, a vitamin D null diet, and a vitamin D enriched diet. Zebrafish grown on a vitamin D null diet between 2–12 months post fertilization (mpf) exhibited diminished somatic growth and enhanced central adiposity associated with accumulation and enlargement of visceral and subcutaneous adipose depots indicative of both adipocyte hypertrophy and hyperplasia. VDD zebrafish exhibited elevated hepatic triglycerides, attenuated plasma free fatty acids and attenuated lipoprotein lipase activity consistent with hallmarks of dyslipidemia. VDD induced dysregulation of gene networks associated with growth hormone and insulin signaling, including induction of suppressor of cytokine signaling. These findings indicate that early developmental VDD impacts metabolic health by disrupting the balance between somatic growth and adipose accumulation.

Evaluation of the suitability of sinkhole ponds and springs from two Portuguese karst massifs for amphibian early life stage development

Amphibians in Portugal are commonly found in karst ecosystems. Nonetheless, these ecosystems are threatened by activities such as agricultural and industrial activities and mining, which contaminate both surface water and groundwater. Due to the high permeability of the karst systems, the existence of water on the surface is scarce, with sinkhole ponds and springs representing essential water sources for amphibians, especially for their reproduction. Furthermore, water from springs may reflect the effects of surface contamination on groundwater. Considering the relevance of these water sources, specially to amphibians, which are considered highly sensitive to a widerange of contaminants, our study aimed at assessing the suitability of water from springs and sinkholes from two Portuguese karst massifs, for the development of the early lifestages of Hyla arborea. To achieve this, eggs from H. arborea were exposed to water from seven springs and four sinkholes, from the Estremenho and Sicó karst massifs, anda control (FETAX). The exposure was carried out with five replicates per condition, each with 20 tadpoles, and ended once the 25th Gosner stage was reached. The parameters evaluated were growth, antioxidant enzyme activity (Glutathione STransferases, Glutathione Peroxidase Se-dependent, total-Glutathione Peroxidase and Glutathione Reductase) and lipid peroxidation (LPO). Also, water samples were screened for the presence of six commonly used pesticides (Terbuthylazine, Tebuconazole, Deltamethrin, Dimethomorph, Chlorpyrifos and Glyphosate). The results revealed the presence of glyphosate in three of the sampled water bodies. Concurrently, in one of the sites presenting detectable glyphosate concentrations, tadpoles presented smaller body lengths, and mortality was also observed. In the remaining sites, despite the absence of the screened pesticides, there were some alterations of the biochemical parameters assessed, namely LPO. These results raised some concerns regarding the impact of human activities in surface and groundwater in the Sicó and Estremenho karst massifs.