Patients poorly recognize lesions of concern that are malignant melanomas: is self-screening the correct advice?

Background: Australia is known for its outdoor culture, with a large percentage of its population engaging in outdoor recreational activities, aquatic, non-aquatic and outdoor occupational activities. However, these outdoor enthusiasts face increased exposure to ultraviolet radiation (UVR), leading to a higher risk of skin cancer, including malignant melanoma (MM). Over the past 40 years, there has been a significant rise in skin cancer rates in Australia, with two out of three Australians expected to develop some form of skin cancer by age 70. Currently, skin cancer examinations are not endorsed in asymptomatic or low-risk individuals in Australia, with only high-risk individuals recommended to undergo regular skin examinations. Notably, the Melanoma Institute Australia suggests that one-half of patients identify MMs themselves, although this claim appears to be based on limited Australian data which may not reflect contemporary practice. Therefore this study sought to determine the percentage of patients who were able to self-identify MMs as lesions of concern when presenting for a skin cancer examination. Methods: Multi-site, cross-sectional study design incorporating a descriptive survey and total body skin cancer screening, including artificial intelligence by a skin cancer doctor. Results: A total of 260 participants with suspect MM lesions were biopsied, with 83 (31.9%) found to be melanomas. Of the true positive MMs only a small percentage of participants (21.7% specificity) correctly had concerns about the suspect lesion being a MM. These MMs were located primarily on the back (44.4%), shoulder (11.1%) and upper leg (11.1%). There was no significant difference in the size between those participants aware of a MM versus those who were not (P = 0.824, 24.6 vs 23.4 mm2). Significantly more males identified lesions of concern that were MMs as compared to females (P = 0.008, 61.1% vs 38.9%, respectively). With regard to true negatives males and females were similar (52.1% vs 47.9%, respectively). With regard to false negatives (n = 65), a greater percentage of males than females did not recognize the MM as a lesion of concern (66.2% vs 33.8%, respectively). Participants were more likely to correctly identify an invasive MM as opposed to an in situ MM (27.3% versus 21.3%). Conclusions: Only a small percentage of participants in this study were able to self-identify either in situ or invasive MM as a lesion of concern with a tendency to identify the more advanced, thicker MMs. Given that MM is associated with a high mortality and cost of treatment, particularly when invasive, the inability of lay persons to identify these cancerous lesions will likely lead to delayed treatment and a possible adverse outcome. We believe the current melanoma screening practices in Australian general practice should be revisited to improve patient outcomes with regard to MM. Additionally, prevention campaigns should include images and primary risk factors for MM.

Heat stress in symbiotic dinoflagellates: Implications on oxidative stress and cellular changes.

Global warming has been shown to harmfully affect symbiosis between Symbiodiniaceae and other marine invertebrates. When symbiotic dinoflagellates (the genus Breviolum) were in vitro exposed to acute heat stress of +7 °C for a period of 5 days, the results revealed the negative impact on all physiological and other cellular parameters measured. Elevated temperatures resulted in a severe reduction in algal density of up to 9.5-fold, as well as pigment concentrations, indicating the status of the physiological stress and early signs of photo-bleaching. Reactive oxygen species (ROS) were increased in all heated dinoflagellate cells, while the antioxidant-reduced glutathione levels initially dropped on day one but increased under prolonged temperature stress. The cell viability parameters were reduced by 97 % over the heating period, with an increased proportion of apoptotic and necrotic cells. Autofluorescence (AF) for Cy5-PE 660-20 was reduced from 1.7-fold at day 1 to up to 50-fold drop at the end of heating time, indicating that the AF changes were highly sensitive to heat stress and that it could be an extremely sensitive tool for assessing the functionality of algal photosynthetic machinery. The addition of the drug 5-AZA-2'-deoxycytidine (5-AZA), which inhibits DNA methylation processes, was assessed in parallel and contributed to some alterations in algal cellular stress response. The presence of drug 5-AZA combined with the temperature stress had an additional impact on Symbiodiniaceae density and cell complexity, including the AF levels. These variations in cellular stress response under heat stress and compromised DNA methylation conditions may indicate the importance of this epigenetic mechanism for symbiotic dinoflagellate thermal tolerance adaptability over a longer period, which needs further exploration. Consequently, the increased ROS levels and changes in AF signals reported during ongoing heat stress in dinoflagellate cells could be used as early stress biomarkers in these microalgae and potentially other photosynthetic species.

Performance of Commercial Dermatoscopic Systems That Incorporate Artificial Intelligence for the Identification of Melanoma in General Practice: A Systematic Review.

BACKGROUND: Cutaneous melanoma remains an increasing global public health burden, particularly in fair-skinned populations. Advancing technologies, particularly artificial intelligence (AI), may provide an additional tool for clinicians to help detect malignancies with a more accurate success rate. This systematic review aimed to report the performance metrics of commercially available convolutional neural networks (CNNs) tasked with detecting MM. METHODS: A systematic literature search was performed using CINAHL, Medline, Scopus, ScienceDirect and Web of Science databases. RESULTS: A total of 16 articles reporting MM were included in this review. The combined number of melanomas detected was 1160, and non-melanoma lesions were 33,010. The performance of market-approved technology and clinician performance for classifying melanoma was highly heterogeneous, with sensitivity ranging from 16.4 to 100.0%, specificity between 40.0 and 98.3% and accuracy between 44.0 and 92.0%. Less heterogeneity was observed when clinicians worked in unison with AI, with sensitivity ranging between 83.3 and 100.0%, specificity between 83.7 and 87.3%, and accuracy between 86.4 and 86.9%. CONCLUSION: Instead of focusing on the performance of AI versus clinicians for classifying melanoma, more consistent performance has been obtained when clinicians' work is supported by AI, facilitating management decisions and improving health outcomes.

Biotechnological Potential of Macroalgae during Seasonal Blooms for Sustainable Production of UV-Absorbing Compounds.

Marine macroalgae (seaweeds) are important primary global producers, with a wide distribution in oceans around the world from polar to tropical regions. Most of these species are exposed to variable environmental conditions, such as abiotic (e.g., light irradiance, temperature variations, nutrient availability, salinity levels) and biotic factors (e.g., grazing and pathogen exposure). As a result, macroalgae developed numerous important strategies to increase their adaptability, including synthesizing secondary metabolites, which have promising biotechnological applications, such as UV-absorbing Mycosporine-Like Amino Acid (MAAs). MAAs are small, water-soluble, UV-absorbing compounds that are commonly found in many marine organisms and are characterized by promising antioxidative, anti-inflammatory and photoprotective properties. However, the widespread use of MAAs by humans is often restricted by their limited bioavailability, limited success in heterologous expression systems, and low quantities recovered from the natural environment. In contrast, bloom-forming macroalgal species from all three major macroalgal clades (Chlorophyta, Phaeophyceae, and Rhodophyta) occasionally form algal blooms, resulting in a rapid increase in algal abundance and high biomass production. This review focuses on the bloom-forming species capable of producing pharmacologically important compounds, including MAAs, and the application of proteomics in facilitating macroalgal use in overcoming current environmental and biotechnological challenges.

Implementation of artificial intelligence for the detection of cutaneous melanoma within a primary care setting: prevalence and types of skin cancer in outdoor enthusiasts.

Background: There is enthusiasm for implementing artificial intelligence (AI) to assist clinicians detect skin cancer. Performance metrics of AI from dermoscopic images have been promising, with studies documenting sensitivity and specificity values equal to or superior to specialists for the detection of malignant melanomas (MM). Early detection rates would particularly benefit Australia, which has the worlds highest incidence of MM per capita. The detection of skin cancer may be delayed due to late screening or the inherent difficulty in diagnosing early skin cancers which often have a paucity of clinical features and may blend into sun damaged skin. Individuals who participate in outdoor sports and recreation experience high levels of intermittent ultraviolet radiation (UVR), which is associated with the development of skin cancer, including MM. This research aimed to assess the prevalence of skin cancer in individuals who regularly participate in activities outdoors and to report the performance parameters of a commercially available AI-powered software to assess the predictive risk of MM development. Methods: Cross-sectional study design incorporating a survey, total body skin cancer screening and AI-embedded software capable of predictive scoring of queried MM. Results: A total of 423 participants consisting of surfers (n = 108), swimmers (n = 60) and walkers/runners (n = 255) participated. Point prevalence for MM was highest for surfers (6.48%), followed by walkers/runners (4.3%) and swimmers (3.33%) respectively. When compared to the general Australian population, surfers had the highest odds ratio (OR) for MM (OR 119.8), followed by walkers/runners (OR 79.74), and swimmers (OR 61.61) rounded out the populations. Surfers and swimmers reported comparatively lower lifetime hours of sun exposure (5,594 and 5,686, respectively) but more significant amounts of activity within peak ultraviolet index compared with walkers/runners (9,554 h). A total of 48 suspicious pigmented lesions made up of histopathology-confirmed MM (n = 15) and benign lesions (n = 33) were identified. The performance of the AI from this clinical population was found to have a sensitivity of 53.33%, specificity of 54.44% and accuracy of 54.17%. Conclusions: Rates of both keratinocyte carcinomas and MM were notably higher in aquatic and land-based enthusiasts compared to the general Australian population. These findings further highlight the clinical importance of sun-safe protection measures and regular skin screening in individuals who spend significant time outdoors. The use of AI in the early identification of MM is promising. However, the lower-than-expected performance metrics of the AI software used in this study indicated reservations should be held before recommending this particular version of this AI software as a reliable adjunct for clinicians in skin imaging diagnostics in patients with potentially sun damaged skin.

Critical disease burdens of Australian adults with cystic fibrosis: Results from an online survey.

BACKGROUND: The objective of this study was to conduct a web-based questionnaire to investigate self-reported phenotypes and disease burdens of individuals living in Australia and diagnosed with cystic fibrosis (CF) using a case-control study design. METHODS: An online questionnaire was distributed to individuals with CF and healthy control subjects. Overall health rating, medications, family history, education, clinical indicators of disease, and symptoms, including their severity and frequency, were evaluated. RESULTS: There was a total of 119 respondents consisting of 59 people living with CF and 60 controls. The CF cohort had significantly lower tertiary educational levels compared to controls. The analysis specific to the CF cohort depicted a significant correlation between the frequency of hospitalizations and the level of education in the CF cohort. Of the 26 self-reported symptoms of CF that were analyzed, 14 were significantly higher in the people living with CF. The CF cohort reporting symptoms of chronic pain (25%) described an increase in the burden of disease, depicting a 30% longer mean hospitalization, increased consumption of medications and significant relationships with four other symptoms, including muscle aches, digestive issues, pancreatic insufficiency, and abdominal swelling. CONCLUSIONS: The nationwide survey identified a diverse range of clinical manifestations experienced by the Australian CF population. Chronic pain, linked to aging and the changing landscape of disease, was a significant indicator of the burden of disease. A comprehensive understanding of the phenotypic profiles and symptom variability will contribute to future research and provide insights into the impacts of disease and the burden of therapy, particularly in children, at the start of their health journey.

Exploring Mycosporine-like Amino Acid UV-Absorbing Natural Products for a New Generation of Environmentally Friendly Sunscreens.

Human skin needs additional protection from damaging ultraviolet radiation (UVR: 280-400 nm). Harmful UVR exposure leads to DNA damage and the development of skin cancer. Available sunscreens offer chemical protection from detrimental sun radiation to a certain extent. However, many synthetic sunscreens do not provide sufficient UVR protection due to the lack of photostability of their UV-absorbing active ingredients and/or the lack of ability to prevent the formation of free radicals, inevitably leading to skin damage. In addition, synthetic sunscreens may negatively affect human skin, causing irritation, accelerating skin aging and even resulting in allergic reactions. Beyond the potential negative effect on human health, some synthetic sunscreens have been shown to have a harmful impact on the environment. Consequently, identifying photostable, biodegradable, non-toxic, and renewable natural UV filters is imperative to address human health needs and provide a sustainable environmental solution. In nature, marine, freshwater, and terrestrial organisms are protected from harmful UVR through several important photoprotective mechanisms, including the synthesis of UV-absorbing compounds such as mycosporine-like amino acids (MAAs). Beyond MAAs, several other promising, natural UV-absorbing products could be considered for the future development of natural sunscreens. This review investigates the damaging impact of UVR on human health and the necessity of using sunscreens for UV protection, specifically UV-absorbing natural products that are more environmentally friendly than synthetic UV filters. Critical challenges and limitations related to using MAAs in sunscreen formulations are also evaluated. Furthermore, we explain how the genetic diversity of MAA biosynthetic pathways may be linked to their bioactivities and assess MAAs' potential for applications in human health.

Genome Mining as an Alternative Way for Screening the Marine Organisms for Their Potential to Produce UV-Absorbing Mycosporine-like Amino Acid.

Mycosporine-like amino acids (MAAs) are small molecules with robust ultraviolet (UV)-absorbing capacities and a huge potential to be used as an environmentally friendly natural sunscreen. MAAs, temperature, and light-stable compounds demonstrate powerful photoprotective capacities and the ability to capture light in the UV-A and UV-B ranges without the production of damaging free radicals. The biotechnological uses of these secondary metabolites have been often limited by the small quantities restored from natural resources, variation in MAA expression profiles, and limited success in heterologous expression systems. Overcoming these obstacles requires a better understanding of MAA biosynthesis and its regulatory processes. MAAs are produced to a certain extent via a four-enzyme pathway, including genes encoding enzymes dehydroquinate synthase, enzyme O-methyltransferase, adenosine triphosphate grasp, and a nonribosomal peptide synthetase. However, there are substantial genetic discrepancies in the MAA genetic pathway in different species, suggesting further complexity of this pathway that is yet to be fully explored. In recent years, the application of genome-mining approaches allowed the identification of biosynthetic gene clusters (BGCs) that resulted in the discovery of many new compounds from unconventional sources. This review explores the use of novel genomics tools for linking BGCs and secondary metabolites based on the available omics data, including MAAs, and evaluates the potential of using novel genome-mining tools to reveal a cryptic potential for new bioproduct screening approaches and unrevealing new MAA producers.

Point prevalence of non-melanoma and melanoma skin cancers in Australian surfers and swimmers in Southeast Queensland and Northern New South Wales.

Background: Surfing and swimming are two popular outdoor aquatic activities in Australia with an estimated 2.7 million surfers and three million swimmers; however, these activities are associated with intermittent exposure to ultraviolet radiation. Our aim was to determine the point prevalence of pre-skin cancer (actinic keratosis (PSC)), non-melanoma (NMSC) and melanoma skin cancers (MSC) in Australian surfers and swimmers. Methods: This cross-sectional study involved Australian surfers who completed a survey that included physiological demographics, aquatic activity-specific demographics, history of skin cancer followed by screening. Results: A total of 171 surfers (n = 116) and swimmers (n = 55) participated in the study. Both groups were identified as having a history of skin cancer (surfers 41.4%, swimmers 36.4%) and a family history of skin cancer (surfers 52.6%, swimmers 43.6%). The majority of both groups reported using a high percentage of a chemical or physical skin cancer prevention strategy (surfers 100%, Swimmers 92.7%, P = 0.003). Significantly more surfers were identified with a skin cancer of any type vs. swimmers (50% vs. 27.3%; OR 2.67; P = 0.005) with most the common skin cancer being PSC (44.7% vs. 11.3%, P = 0.076) followed by basal cell carcinoma (BCC) (24.2% vs. 7.6%, P = 0.068). There was a total of seven MSC identified in surfers and swimmers (4.6% vs. 0.8%, respectively, P = 0.137). Most skin cancers in surfers were located on the face (28.0%) followed by the arm and back (12.1% each), whereas in swimmers, the majority of skin cancers were identified on the face (17.3%), followed by the arm and lower leg (15.4% each). The highest number of melanomas were identified in surfers (n = 6) and mainly located on the face (n = 2) and back (n = 2). There was a single melanoma identified on the back in a swimmer. With the groups combined, the majority (42.9%) of melanomas were identified on the back in participants, followed by the face (28.6%). Rates per 100,000 of NMSC and MSC in surfers and swimmers (respectively) were BCC (11,206 vs. 14,545), squamous cell carcinoma (SCC) in situ (13,793 vs. 12,727), SCC (1,724 vs. 3,636) and MSC (5,172 vs. 1,818). When compared to the general Australian population, surfers and swimmers had higher odds ratios (OR), which included BCCs (OR 7.3 and 9.4, respectively), SCCs (OR 1.7 and 3.5, respectively) and MSC (OR 96.7 and 18.8, respectively). Conclusion: Surfers and swimmers had consistently higher rates of PSC, NMSC and MSC than the general Australian population. Point prevalence of MSC (groups combined) was 76-fold higher than the general Australian population. These findings highlight the clinical importance of regular skin cancer screenings in individuals who surf or swim for early detection and treatment of skin cancer. Additionally, these aquatic enthusiasts should be advised of the benefits of sun protection strategies such as chemical and physical barriers to reduce the likelihood of developing skin cancer.

Recent advances in the discovery of novel marine natural products and mycosporine-like amino acid UV-absorbing compounds.

Bioactive compounds from marine environments represent a rich source of bioproducts for potential use in medicine and biotechnology. To discover and identify novel marine natural products (MNPs), evaluating diverse biological activities is critical. Increased sensitivity and specificity of omics technologies, especially next-generation high-throughput sequencing combined with liquid chromatography-mass spectrometry and nuclear magnetic resonance, are speeding up the discovery of novel bioactive compounds. Mycosporine-like amino acids (MAAs) isolated from many marine microorganisms are among highly promising MNPs characterized by ultraviolet radiation (UV) absorbing capacities and are recognized as a potential source of ecologically friendly sunscreens. MAAs absorb damaging UV radiation with maximum absorption in the range of 310-360 nm, including both UVA and UVB ranges. MAAs are also characterized by other biological activities such as anti-oxidant, anti-cancer, and anti-inflammatory activities. The application of modern omics approaches promoted some recent developments in our understanding of MAAs' functional significance and diversity. This review will summarize the various modern tools that could be applied during the identification and characterization of MNPs, including MAAs, to further their innovative applications. KEY POINTS: • New omics technologies are speeding up the discovery of novel bio-products • The vast diversity of bioactive capacities of marine natural products described • Marine microorganisms as a source of environmentally friendly sunscreens.

Marine heatwaves have minimal influence on the quality of adult Sydney rock oyster flesh.

Marine heatwaves (MHWs) are impacting marine biodiversity, including fisheries and aquaculture. However, it is largely unknown which species will be able to endure MHWs and at what price. Here, we applied elevated temperature (2 °C above ambient) and two different heatwave scenarios to adults of the economically important Sydney rock oyster (SRO, Saccostrea glomerata), and evaluated the impact on nutritional properties, gene expression profiles and immune health indicators. We found that elevated temperature (23 °C) and a variable heatwave (VHW) during winter caused some significant differences in the micronutrient and trace elements levels in oyster flesh. There was an increase of lead under VHW and a decrease in chromium, barium and aluminium under elevated temperature. Conversely, gene expression profiles and other physiological parameters, including flesh protein, fatty acid profiles and hemocyte numbers, were not affected by MHWs. These results indicate that adult SRO are reasonably resilient, and should continue to provide high-quality seafood, under near-future ocean warming and moderate heatwave scenarios.

Differential impact of heat stress on reef-building corals under different light conditions.

Heat stress is an environmental factor that regularly challenges the well-being of living organisms. This study aims to examine the physiological changes happening in two reef-building coral species exposed to thermal stress under various light conditions. The two ecologically relevant heatwave scenarios were applied under ambient lights (high irradiance) and reduced light conditions (250 and < 10 µmol photons m-2 s-1). Corals were exposed to elevated temperatures of 32°C (plus 6°) for a period of 1 up to 5 days corresponding to heatwaves reported on the Great Barrier Reef (GBR) that were associated with coral bleaching. We monitored changes in the physiological performance of these two coral species by measuring symbionts and corals' physiological parameters including symbiont density, levels of multiple algal pigments (chlorophyll a and peridinin), as well as the changes in the host protein concentration. During the short-term heat stress, both species were with stable physiological performance with the only exception of Stylophora pistillata under ambient lights. These results show that S. pistillata was negatively influenced by a synergistic effect of temperature and high irradiance resulting in the first signs of bleaching after only 24h of thermal stress. Exposure to prolonged thermal stress, characterised with a slower rate of temperature increase, affected both coral species investigated and resulted in bleaching mainly by day 5. Interestingly, severe light reduction (<10 µmol photons m-2 s-1) made Acropora millepora corals more thermally sensitive and resulted in earlier signs of bleaching (on day 3). These findings indicate that there was a synergistic effect of very low lights and thermal stress that caused higher levels of bleaching in A. millepora. Our results revealed differential thermal sensitivity for two branching corals exposed to different thermal stress scenarios under various light irradiance conditions, naturally found in their existing habitats. Consequently, global warming may have a differential impact on coral reef biodiversity depending on light availability.

Mycosporine-Like Amino Acids: Making the Foundation for Organic Personalised Sunscreens.

The surface of the Earth is exposed to harmful ultraviolet radiation (UVR: 280-400 nm). Prolonged skin exposure to UVR results in DNA damage through oxidative stress due to the production of reactive oxygen species (ROS). Mycosporine-like amino acids (MAAs) are UV-absorbing compounds, found in many marine and freshwater organisms that have been of interest in use for skin protection. MAAs are involved in photoprotection from damaging UVR thanks to their ability to absorb light in both the UV-A (315-400 nm) and UV-B (280-315 nm) range without producing free radicals. In addition, by scavenging ROS, MAAs play an antioxidant role and suppress singlet oxygen-induced damage. Currently, there are over 30 different MAAs found in nature and they are characterised by different antioxidative and UV-absorbing capacities. Depending on the environmental conditions and UV level, up- or downregulation of genes from the MAA biosynthetic pathway results in seasonal fluctuation of the MAA content in aquatic species. This review will provide a summary of the MAA antioxidative and UV-absorbing features, including the genes involved in the MAA biosynthesis. Specifically, regulatory mechanisms involved in MAAs pathways will be evaluated for controlled MAA synthesis, advancing the potential use of MAAs in human skin protection.

A differential k-mer analysis pipeline for comparing RNA-Seq transcriptome and meta-transcriptome datasets without a reference.

Next-generation DNA sequencing technologies, such as RNA-Seq, currently dominate genome-wide gene expression studies. A standard approach to analyse this data requires mapping sequence reads to a reference and counting the number of reads which map to each gene. However, for many transcriptome studies, a suitable reference genome is unavailable, especially for meta-transcriptome studies which assay gene expression from mixed populations of organisms. Where a reference is unavailable, it is possible to generate a reference by the de novo assembly of the sequence reads. However, the high cost of generating high-coverage data for de novo assembly hinders this approach and more importantly the accurate assembly of such data is challenging, especially for meta-transcriptome data, and resulting assemblies frequently suffer from collapsed regions or chimeric sequences. As an alternative to the standard reference mapping approach, we have developed a k-mer-based analysis pipeline (DiffKAP) to identify differentially expressed reads between RNA-Seq datasets without the requirement for a reference. We compared the DiffKAP approach with the traditional Tophat/Cuffdiff method using RNA-Seq data from soybean, which has a suitable reference genome. We subsequently examined differential gene expression for a coral meta-transcriptome where no reference is available, and validated the results using qRT-PCR. We conclude that DiffKAP is an accurate method to study differential gene expression in complex meta-transcriptomes without the requirement of a reference genome.

Author Correction: Recurrent acquisition of cytosine methyltransferases into eukaryotic retrotransposons.

The original version of this Article contained an error in the spelling of the author Hongfei Li, which was incorrectly given as Fei Hong. This has now been corrected in both the PDF and HTML versions of the Article.

Recurrent acquisition of cytosine methyltransferases into eukaryotic retrotransposons.

Transposable elements are in a constant arms race with the silencing mechanisms of their host genomes. One silencing mechanism commonly used by many eukaryotes is dependent on cytosine methylation, a covalent modification of DNA deposited by C5 cytosine methyltransferases (DNMTs). Here, we report how two distantly related eukaryotic lineages, dinoflagellates and charophytes, have independently incorporated DNMTs into the coding regions of distinct retrotransposon classes. Concomitantly, we show that dinoflagellates of the genus Symbiodinium have evolved cytosine methylation patterns unlike any other eukaryote, with most of the genome methylated at CG dinucleotides. Finally, we demonstrate the ability of retrotransposon DNMTs to methylate CGs de novo, suggesting that retrotransposons could self-methylate retrotranscribed DNA. Together, this is an example of how retrotransposons incorporate host-derived genes involved in DNA methylation. In some cases, this event could have implications for the composition and regulation of the host epigenomic environment.

Transcriptomic Changes in Coral Holobionts Provide Insights into Physiological Challenges of Future Climate and Ocean Change.

Tropical reef-building coral stress levels will intensify with the predicted rising atmospheric CO2 resulting in ocean temperature and acidification increase. Most studies to date have focused on the destabilization of coral-dinoflagellate symbioses due to warming oceans, or declining calcification due to ocean acidification. In our study, pH and temperature conditions consistent with the end-of-century scenarios of the Intergovernmental Panel on Climate Change (IPCC) caused major changes in photosynthesis and respiration, in addition to decreased calcification rates in the coral Acropora millepora. Population density of symbiotic dinoflagellates (Symbiodinium) under high levels of ocean acidification and temperature (Representative Concentration Pathway, RCP8.5) decreased to half of that found under present day conditions, with photosynthetic and respiratory rates also being reduced by 40%. These physiological changes were accompanied by evidence for gene regulation of calcium and bicarbonate transporters along with components of the organic matrix. Metatranscriptomic RNA-Seq data analyses showed an overall down regulation of metabolic transcripts, and an increased abundance of transcripts involved in circadian clock control, controlling the damage of oxidative stress, calcium signaling/homeostasis, cytoskeletal interactions, transcription regulation, DNA repair, Wnt signaling and apoptosis/immunity/ toxins. We suggest that increased maintenance costs under ocean acidification and warming, and diversion of cellular ATP to pH homeostasis, oxidative stress response, UPR and DNA repair, along with metabolic suppression, may underpin why Acroporid species tend not to thrive under future environmental stress. Our study highlights the potential increased energy demand when the coral holobiont is exposed to high levels of ocean warming and acidification.

Extraction and Analysis of Mycosporine-Like Amino Acids in Marine Algae.

Marine organisms use mycosporine-like amino acids (MAAs) as biological sunscreens for the protection from damaging ultraviolet (UV) radiation and the prevention of oxidative stress. MAAs have been discovered in many different marine and freshwater species including cyanobacteria, fungi, and algae, but also in animals like cnidarian and fishes. Here, we describe a general method for the isolation and characterization of MAA compounds from red algae and symbiotic dinoflagellates isolated from coral hosts. This method is also suitable for the extraction and analyses of MAAs from a range of other algal and marine biota.

Unfolding the secrets of coral-algal symbiosis.

Dinoflagellates from the genus Symbiodinium form a mutualistic symbiotic relationship with reef-building corals. Here we applied massively parallel Illumina sequencing to assess genetic similarity and diversity among four phylogenetically diverse dinoflagellate clades (A, B, C and D) that are commonly associated with corals. We obtained more than 30,000 predicted genes for each Symbiodinium clade, with a majority of the aligned transcripts corresponding to sequence data sets of symbiotic dinoflagellates and <2% of sequences having bacterial or other foreign origin. We report 1053 genes, orthologous among four Symbiodinium clades, that share a high level of sequence identity to known proteins from the SwissProt (SP) database. Approximately 80% of the transcripts aligning to the 1053 SP genes were unique to Symbiodinium species and did not align to other dinoflagellates and unrelated eukaryotic transcriptomes/genomes. Six pathways were common to all four Symbiodinium clades including the phosphatidylinositol signaling system and inositol phosphate metabolism pathways. The list of Symbiodinium transcripts common to all four clades included conserved genes such as heat shock proteins (Hsp70 and Hsp90), calmodulin, actin and tubulin, several ribosomal, photosynthetic and cytochrome genes and chloroplast-based heme-containing cytochrome P450, involved in the biosynthesis of xanthophylls. Antioxidant genes, which are important in stress responses, were also preserved, as were a number of calcium-dependent and calcium/calmodulin-dependent protein kinases that may play a role in the establishment of symbiosis. Our findings disclose new knowledge about the genetic uniqueness of symbiotic dinoflagellates and provide a list of homologous genes important for the foundation of coral-algal symbiosis.