Publications by authors named "Lesley Rhodes"

Photosynthetic eukaryotic microalgae are key primary producers in the Antarctic sea ice environment. Anticipated changes in sea ice thickness and snow load due to climate change may cause substantial shifts in available light to these ice-associated organisms. This study used a laboratory-based experiment to investigate how light levels, simulating different sea ice and snow thicknesses, affect fatty acid (FA) composition in two ice associated microalgae species, the pennate diatom Nitzschia cf.

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  • Vitamin D production in the skin begins when UV radiation converts the precursor 7-dehydrocholesterol into vitamin D, but how age affects this process is unclear.
  • A study was conducted with healthy adults aged 18-40 and 65-89 to compare skin 7DHC levels and vitamin D response after UV exposure.
  • Results showed no significant difference in 7DHC levels or vitamin D increase between younger and older adults, indicating that older adults can still effectively produce vitamin D from sunlight.
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  • The study mapped the metabolite profiles of 34 isolates from 13 different species, identifying a total of 56 secondary metabolites produced by these organisms.
  • Notably, only specific species were found to produce particular toxins, such as Pacific-ciguatoxins and maitotoxins, with ubiquitous production of 44-methylgambierone across all isolates.
  • The findings suggest that while the isolates produce known ciguatoxins (CTXs) or maitotoxins (MTXs), they do not produce both, and point to the presence of uncharacterized compounds that warrant further investigation.
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The Symbiodinium genus is ancestral among other Symbiodiniaceae lineages with species that are both symbiotic and free living. Changes in marine ecosystems threaten their existence and crucial ecological roles. Cryopreservation offers an avenue for their long-term storage for future habitat restoration after coral bleaching.

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  • Solar urticaria is a rare skin condition where sunlight triggers rapid hives, but its underlying mechanisms remain unclear.* -
  • A study examined skin samples from patients with solar urticaria and healthy controls after UV radiation exposure, revealing increased activity of immune pathways, particularly involving neutrophils and pro-inflammatory molecules.* -
  • Results indicate that mast cell activation and specific immune responses are essential in the development of solar urticaria, with potential similarities to chronic spontaneous urticaria, highlighting unique biomarkers for the condition.*
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Benthic dinoflagellates that can cause illness, such as ciguatera poisoning (CP), are prevalent around the Pacific but are poorly described in many locations. This study represents the first ecological assessment of benthic harmful algae species in the Kingdom of Tonga, a country where CP occurs regularly. Surveys were conducted in June 2016 in the Tongatapu island group, and in June 2017 across three island groups: Ha'apai, Vava'u, and Tongatapu.

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Temperatures and temperature anomalies have been increasing in the sub-tropical regions of Aotearoa New Zealand and these changes may impact on harmful algal bloom (HAB) events. Benthic and epiphytic dinoflagellates, particularly the toxin producers, are the focus of this study as it is predicted that under future climate conditions they may produce more toxins or marine animals may become more susceptible to them. The results of past expeditions to Rangitāhua Kermadec Islands and sampling trips to Northland, Aotearoa New Zealand, are summarised and the results of the most recent trips to both regions are presented.

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Many strains of Symbiodiniaceae have been isolated and their genetics, taxonomy, and metabolite production studied. Maintaining these cultures requires careful and regular sub-culturing that is costly with a high risk of species contamination or loss. Cryopreservation is a viable alternative for their long-term storage; however, there is uncertainty as to whether cryopreservation impacts the photosynthetic performance of Symbiodiniaceae.

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  • There is a lack of comprehensive data on the prevalence of photodermatoses, which significantly affect quality of life, prompting a systematic review of existing literature on this topic.
  • The review examined 26 studies, identifying 15 that reported the prevalence of various photodermatoses in general populations and 11 from national and international registries, finding that polymorphic light eruption (PLE) was the most commonly studied condition.
  • Results revealed a global pooled prevalence of PLE at around 10% among the general population, with prevalence rates varying widely by country and increasing with distance from the equator, highlighting its notable presence in diverse locations like Egypt.
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An increase in cases of ciguatera poisoning (CP) and expansion of the causative species in the South Pacific region highlight the need for baseline data on toxic microalgal species to help identify new areas of risk and manage known hot spots. Gambierdiscus honu is a toxin producing and potential CP causing dinoflagellate species, first described in 2017. Currently no high-resolution geographical distribution, intraspecific genetic variation or toxin production diversity data is available for G.

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Background: UVB absorption by 7-dehydrocholesterol (7DHC) in the skin triggers the production of vitamin D and its metabolites, which maintain calcium homeostasis. Detection and measurement of 7DHC in skin using modern liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques have been lacking, yet there is need for such a technique to provide more information on 7DHC concentration and its UVB responses in human skin.

Objectives: To develop and validate a reliable method to measure 7DHC concentration in skin.

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Importance: Photoaggravated atopic dermatitis (PAD) is estimated to affect 1.4% to 16% of patients with AD but remains poorly characterized with limited published data.

Objective: To provide detailed clinical and photobiological characterization of PAD.

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Identifying compounds responsible for the observed toxicity of the species is a critical step to ascertaining whether they contribute to ciguatera poisoning. Macroalgae samples were collected during research expeditions to Rarotonga (Cook Islands) and North Meyer Island (Kermadec Islands), from which two new species were characterized, CAWD232 and CAWD242. Previous chemical and toxicological investigations of these species demonstrated that they did not produce the routinely monitored Pacific ciguatoxins nor maitotoxin-1 (MTX-1), yet were highly toxic to mice via intraperitoneal (i.

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Symbiodiniaceae are a diverse group of dinoflagellates, the majority of which are free-living and/or associated with a variety of protists and other invertebrate hosts. Maintenance of isolated cultures is labour-intensive and expensive, and cryopreservation provides an excellent avenue for their long-term storage. We aimed to cryopreserve 15 cultured isolates from six Symbiodiniaceae genera using dimethyl sulfoxide (DMSO) as the cryoprotectant agent (CPA).

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Harmful algal blooms (HABs) have wide-ranging environmental impacts, including on aquatic species of social and commercial importance. In New Zealand (NZ), strategic growth of the aquaculture industry could be adversely affected by the occurrence of HABs. This review examines HAB species which are known to bloom both globally and in NZ and their effects on commercially important shellfish and fish species.

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Background: Loss and remodelling of the dermal extracellular matrix (ECM) are key features of photodamaged human skin. Green tea catechins (GTCs) have been explored for their anti-inflammatory and chemopreventive properties, but data on the impact of GTCs on ultraviolet radiation (UVR)-induced changes to the dermal ECM are lacking.

Aim: To investigate the effect of an inflammatory dose of solar-simulated UVR on human dermal ECM and potential for protection by GTCs in a double-blind randomized controlled trial.

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Background: The use of indoor tanning devices causes melanoma and other skin cancers with resulting morbidity, mortality and increased healthcare costs. Policymakers require robust economic evidence to inform decisions about a possible ban of such devices to mitigate these burdens.

Objectives: To assess the health costs and consequences of introducing a policy-based intervention across England to ban commercial indoor tanning with an accompanying public information campaign.

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Dinoflagellates are among the most diverse group of microalgae. Many dinoflagellate species have been isolated and cultured, and these are used for scientific, industrial, pharmaceutical, and agricultural applications. Maintaining cultures is time-consuming, expensive, and there is a risk of contamination or genetic drift.

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Solar ultraviolet radiation (UVR) is a major source of skin damage, resulting in inflammation, premature ageing, and cancer. While several UVR-induced changes, including extracellular matrix reorganisation and epidermal DNA damage, have been documented, the role of different fibroblast lineages and their communication with immune cells has not been explored. We show that acute and chronic UVR exposure led to selective loss of fibroblasts from the upper dermis in human and mouse skin.

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Domoic acid (DA) is produced by almost half of the species belonging to the diatom genus and causes amnesic shellfish poisoning (ASP). It is, therefore, important to investigate the diversity and toxin production of species for ASP risk assessments. Between 2018 and 2020, seawater samples were collected from various sites around Aotearoa New Zealand, and 130 clonal isolates of were established.

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