A scuticociliate causes mass mortality of Diadema antillarum in the Caribbean Sea.

Echinoderm mass mortality events shape marine ecosystems by altering the dynamics among major benthic groups. The sea urchin Diadema antillarum, virtually extirpated in the Caribbean in the early 1980s by an unknown cause, recently experienced another mass mortality beginning in January 2022. We investigated the cause of this mass mortality event through combined molecular biological and veterinary pathologic approaches comparing grossly normal and abnormal animals collected from 23 sites, representing locations that were either affected or unaffected at the time of sampling. Here, we report that a scuticociliate most similar to Philaster apodigitiformis was consistently associated with abnormal urchins at affected sites but was absent from unaffected sites. Experimentally challenging naïve urchins with a Philaster culture isolated from an abnormal, field-collected specimen resulted in gross signs consistent with those of the mortality event. The same ciliate was recovered from treated specimens postmortem, thus fulfilling Koch's postulates for this microorganism. We term this condition D. antillarum scuticociliatosis.

Putting midodrine on the MAP: An approach to liberation from intravenous vasopressors in vasodilatory shock.

PURPOSE: Prolonged duration of intravenous (IV) vasopressor dependence in critically ill adult patients with vasodilatory shock results in increased length of stay in both the intensive care unit (ICU) and hospital, translating to higher risk of infection, delirium, immobility, and cost. Acceleration of vasopressor liberation can aid in reducing these risks. Midodrine is an oral α 1-adrenergic receptor agonist that offers a potential means of liberating patients from IV vasopressor therapy. This clinical review summarizes primary literature and proposes a clinical application for midodrine in the recovery phase of vasodilatory shock. SUMMARY: Five studies with a total of over 1,000 patients conducted between 2011 and 2021 were identified. In observational studies, midodrine administration was demonstrated to lead to faster time to liberation from IV vasopressor therapy and shorter ICU length of stay in patients recovering from vasodilatory shock. These findings were not replicated in a prospective, multicenter, randomized controlled trial. In this review, literature evaluating midodrine use for IV vasopressor liberation is summarized and study limitations are discussed. CONCLUSION: On the basis of this review of current literature, recommendations are provided on selecting appropriate candidates for adjunctive midodrine in the recovery phase of vasodilatory shock and considerations are discussed for safely and effectively initiating, titrating, and discontinuing therapy.

Intraspecific variation in polar and nonpolar metabolite profiles of a threatened Caribbean coral.

INTRODUCTION: Research aimed at understanding intraspecific variation among corals could substantially increase understanding of coral biology and improve outcomes of active restoration efforts. Metabolomics is useful for identifying physiological drivers leading to variation among genotypes and has the capacity to improve our selection of candidate corals that express phenotypes beneficial to restoration. OBJECTIVES: Our study aims to compare metabolomic profiles among known, unique genotypes of the threatened coral Acropora cervicornis. In doing so, we seek information related to the physiological characteristics driving variation among genotypes, which could aid in identifying genets with desirable traits for restoration. METHODS: We applied proton nuclear magnetic resonance (1H-NMR) and liquid chromatography-mass spectrometry (LC-MS) to identify and compare metabolomic profiles for seven unique genotypes of A. cervicornis that previously exhibited phenotypic variation in a common garden coral nursery. RESULTS: Significant variation in polar and nonpolar metabolite profiles was found among A. cervicornis genotypes. Despite difficulties identifying all significant metabolites driving separation among genotypes, our data support previous findings and further suggest metabolomic profiles differ among various genotypes of the threatened species A. cervicornis. CONCLUSION: The implementation of metabolomic analyses allowed identification of several key metabolites driving separation among genotypes and expanded our understanding of the A. cervicornis metabolome. Although our research is specific to A. cervicornis, these findings have broad relevance for coral biology and active restoration. Furthermore, this study provides specific information on the understudied A. cervicornis metabolome and further confirmation that differences in metabolome structure could drive phenotypic variation among genotypes.

A novel system for intensive Diadema antillarum propagation as a step towards population enhancement.

The long-spined sea urchin Diadema antillarum was once an abundant reef grazing herbivore throughout the Caribbean. During the early 1980s, D. antillarum populations were reduced by > 93% due to an undescribed disease. This event resulted in a lack of functional reef herbivory and contributed to ongoing ecological shifts from hard coral towards macroalgae dominated reefs. Limited natural recovery has increased interest in a range of strategies for augmenting herbivory. An area of focus has been developing scalable ex situ methods for rearing D. antillarum from gametes. The ultimate use of such a tool would be exploring hatchery origin restocking strategies. Intensive ex situ aquaculture is a potentially viable, yet difficult, method for producing D. antillarum at scales necessary to facilitate restocking. Here we describe a purpose-built, novel recirculating aquaculture system and the broodstock management and larval culture process that has produced multiple D. antillarum cohorts, and which has the potential for practical application in a dedicated hatchery setting. Adult animals held in captivity can be induced to spawn year-round, with some evidence for annual and lunar periodicity. Fecundity and fertilization rates are both consistently very high, yet challenges persist in both late stage larval development and early post-settlement survival. Initial success was realized with production of 100 juvenile D. antillarum from ~ 1200 competent larvae. While the system we describe requires a significant level of investment and technical expertise, this work advances D. antillarum culture efforts in potential future hatchery settings and improves the viability of scalable ex situ production for population enhancement.

Growth, calcification, and photobiology of the threatened coral Acropora cervicornis in natural versus artificial light.

Land-based coral culture is of increasing interest for conservation and educational display. Shallow water corals generate most of their energy from photosynthesis, and light is a critical abiotic factor in their husbandry. We compared growth, calcification, and photobiology in the coral Acropora cervicornis between natural and artificial (light-emitting diode; LED) light to better understand the impact of light source on coral performance. One tank of a greenhouse recirculating system at The Florida Aquarium's Center for Conservation was used to culture replicate coral colonies. Half of the tank and corals were covered to block sunlight and illuminated with a commercial reef aquarium LED fixture, while the other half was exposed to natural sunlight. Treatments were matched in terms of maximum photosynthetically active radiation and spectral measurements characterized both light regimes. Coral growth and calcification were tracked over a period of 19 weeks by repeated measurements of total linear extension (TLE) and buoyant weight. For the first 5 weeks, photosynthetic yield was measured weekly using a pulse-amplitude-modulated fluorometer. Calcification was significantly higher under LED lighting relative to natural light, but TLE did not differ. Photobiology data suggest that corals in both treatments were acclimated to the same light level, but photosynthetic efficiency was ultimately greater in the natural light treatment. More consistent light delivery and different spectral composition under LED treatment conditions may explain the incongruity between calcification and photosynthetic efficiency. This experiment informs husbandry of shallow-water scleractinian corals maintained in both natural sunlight and enclosed structures.

Coastal restoration evaluated using dominant habitat characteristics and associated fish communities.

Increasing coastal populations and urban development have led to the loss of estuarine habitats for fish and wildlife. Specifically, a decline in complexity and heterogeneity of tidal marshes and creeks is thought to negatively impact fish communities by altering the function of nursery grounds, including predator refuge and prey resources. To offset these impacts, numerous agencies are restoring degraded habitats while also creating new ones where habitat has been lost. To improve understanding of what contributes to a successful restoration, six quarterly sampling events using two gear types to collect small- and large-bodied fishes were conducted to compare the fish community structure and habitat characteristics at three natural, three restored, and three impacted (i.e. ditched) areas along the coast of Tampa Bay, Florida. Overall, impacted sites had significantly lower small-bodied and juvenile fish diversity than natural and restored areas, while restored sites harbored a greater number of fish species than impacted sites for both large- and small-bodied fish. Habitat features such as shoreline slope differentiated impacted and restored from natural areas. Although we did not find a direct correlation, habitat heterogeneity likely played a role in structuring fish communities. These findings provide guidance for future coastal restoration or modification of existing projects. Specifically, the habitat mosaic approach of creating a geographically compact network of heterogenous habitat characteristics is likely to support fish diversity, while decreasing shoreline slope in a greater amount of area within coastal wetland restorations would more closely mimic natural areas.

Metabolomic profiles differ among unique genotypes of a threatened Caribbean coral.

Global threats to reefs require urgent efforts to resolve coral attributes that affect survival in a changing environment. Genetically different individuals of the same coral species are known to exhibit different responses to the same environmental conditions. New information on coral physiology, particularly as it relates to genotype, could aid in unraveling mechanisms that facilitate coral survival in the face of stressors. Metabolomic profiling detects a large subset of metabolites in an organism, and, when linked to metabolic pathways, can provide a snapshot of an organism's physiological state. Identifying metabolites associated with desirable, genotype-specific traits could improve coral selection for restoration and other interventions. A key step toward this goal is determining whether intraspecific variation in coral metabolite profiles can be detected for species of interest, however little information exists to illustrate such differences. To address this gap, we applied untargeted 1H-NMR and LC-MS metabolomic profiling to three genotypes of the threatened coral Acropora cervicornis. Both methods revealed distinct metabolite "fingerprints" for each genotype examined. A number of metabolites driving separation among genotypes were identified or putatively annotated. Pathway analysis suggested differences in protein synthesis among genotypes. For the first time, these data illustrate intraspecific variation in metabolomic profiles for corals in a common garden. Our results contribute to the growing body of work on coral metabolomics and suggest future work could identify specific links between phenotype and metabolite profile in corals.

Resolving coral photoacclimation dynamics through coupled photophysiological and metabolomic profiling.

Corals continuously adjust to short-term variation in light availability on shallow reefs. Long-term light alterations can also occur as a result of natural and anthropogenic stressors, as well as management interventions such as coral transplantation. Although short-term photophysiological responses are relatively well understood in corals, little information is available regarding photoacclimation dynamics over weeks of altered light availability. We coupled photophysiology and metabolomic profiling to explore changes that accompany longer-term photoacclimation in a key Great Barrier Reef coral species, Acropora muricata High light (HL)- and low light (LL)-acclimated corals were collected from the reef and reciprocally exposed to high and low light ex situ Rapid light curves using pulse-amplitude modulation (PAM) fluorometry revealed photophysiological acclimation of LL corals to HL and HL corals to LL within 21 days. A subset of colonies sampled at 7 and 21 days for untargeted LC-MS and GC-MS metabolomic profiling revealed metabolic reorganization before acclimation was detected using PAM fluorometry. Metabolomic shifts were more pronounced for LL to HL corals than for their HL to LL counterparts. Compounds driving metabolomic separation between HL-exposed and LL control colonies included amino acids, organic acids, fatty acids and sterols. Reduced glycerol and campesterol suggest decreased translocation of photosynthetic products from symbiont to host in LL to HL corals, with concurrent increases in fatty acid abundance indicating reliance on stored lipids for energy. We discuss how these data provide novel insight into environmental regulation of metabolism and implications for management strategies that drive rapid changes in light availability.

Interfacial Structure and Partitioning of Nitrate Ions in Reverse Micelles.

The interfacial properties of NO3- were investigated using reverse micelles (RMs) in solution as proxies for sea spray aerosol (SSA) particles. By tuning the size of bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT) RMs doped with NO3- we are able to isolate the vibrational signature of interfacial NO3- using infrared spectroscopy. The infrared spectrum of interfacial NO3- along the asymmetric-stretch coordinate (υ3) is blue-shifted and possesses smaller peak splitting relative to NO3- in aqueous solution. These observations are consistent with the reduced hydrogen-bonding availability of the interfacial region within the RM aqueous interior. We show that the partitioning of NO3- between the interfacial and core regions of the RM interior can be determined using a linear combination of interfacial and aqueous NO3- spectra. By fitting the interfacial partitioning curve of NO3- we demonstrate a method of determining quantitative interfacial affinity (χInterface) for ionic species doped within RMs.

A three-dimensional spatial mapping approach to quantify fine-scale heterogeneity among leaves within canopies.

PREMISE OF THE STUDY: The three-dimensional structure of tree canopies creates environmental heterogeneity, which can differentially influence the chemistry, morphology, physiology, and/or phenology of leaves. Previous studies that subdivide canopy leaves into broad categories (i.e., "upper/lower") fail to capture the differences in microenvironments experienced by leaves throughout the three-dimensional space of a canopy. METHODS: We use a three-dimensional spatial mapping approach based on spherical polar coordinates to examine the fine-scale spatial distributions of photosynthetically active radiation (PAR) and the concentration of ultraviolet (UV)-absorbing compounds (A300) among leaves within the canopies of black mangroves (Avicennia germinans). RESULTS: Linear regressions revealed that interior leaves received less PAR and produced fewer UV-absorbing compounds than leaves on the exterior of the canopy. By allocating more UV-absorbing compounds to the leaves on the exterior of the canopy, black mangroves may be maximizing UV-protection while minimizing biosynthesis of UV-absorbing compounds. DISCUSSION: Three-dimensional spatial mapping provides an inexpensive and portable method to detect fine-scale differences in environmental and biological traits within canopies. We used it to understand the relationship between PAR and A300, but the same approach can also be used to identify traits associated with the spatial distribution of herbivores, pollinators, and pathogens.

Right Middle Lobe Collapse and Pleural Effusion in an 18-Year-Old Man.

An 18-year-old African American male subject presented to an acute care clinic with 3 days of productive cough, chills, pleuritic right chest pain, sore throat with hoarseness, congestion, and intermittent shortness of breath. He recently relocated to Texas from Georgia to undergo basic military training. He denied any other recent travel or contact with persons with pulmonary TB or other respiratory illnesses. His medical history was significant for glucose-6-phosphate dehydrogenase deficiency and sickle cell trait.

Physiological management of dietary deficiency in n-3 fatty acids by spawning Gulf killifish (Fundulus grandis).

Lipid dynamics of spawning fish are critical to the production of viable embryos and larvae. The present study utilized manipulation of dietary fatty acid (FA) profiles to examine the ability of spawning Gulf killifish (Fundulus grandis) to mobilize critical lipid components from somatic reserves or synthesize long-chain polyunsaturated FAs (LC-PUFAs) de novo from shorter-chain C18 precursors. An egg and multi-tissue evaluation of changes in FA concentrations across time after fish were switched from LC-PUFA-rich to LC-PUFA-deficient experimental diets was employed. The two experimental diets contained lipid sources which differed drastically in n-3 C18 FA content but had similar levels of n-6 C18 FAs. Discrete effects of dietary n-3 FAs can be analyzed because n-3 and n-6 represent distinct metabolic families which cannot be exchanged in vivo. Results indicate that a combination of mobilization and de novo synthesis is likely utilized to maintain physiologically required FA levels in critical tissues and embryos. Mobilization was supported by decreases in LC-PUFAs in somatic tissues and decreases in intraperitoneal fat content and liver mass. Evidence for biosynthesis was provided by a higher level of n-3 LC-PUFAs in the liver and ova of fish fed diets containing n-3 C18 precursors versus those fed diets with low levels of precursor FAs. The characteristic physiological plasticity of Gulf killifish is exemplified in the nutritional domain by its management of dietary FA deficiency.

Diet-induced fatty acid variation in critical tissues of a spawning estuarine fish and consequences for larval fitness.

Freshwater and marine fishes exhibit a dichotomy in biosynthesis of long-chain polyunsaturated fatty acids (LC-PUFAs) from shorter-chain precursors. Marine species generally lack this ability due to deficiencies in requisite desaturase or elongase enzymes. Gulf killifish Fundulus grandis is a euryhaline cyprinodont whose fatty acid (FA) dynamics have not been previously examined. We utilized experimental variations in exogenous FAs available to spawning F. grandis in order to construct a multitissue evaluation of FA allocation and quantify effects on reproductive output and offspring fitness. No significant decrease in fecundity occurred in animals consuming low levels of LC-PUFAs, although embryo viability rates were affected. Maternal dietary FA variation did produce differences in starvation tolerance, hypoosmoregulatory ability, and acute thermal stress tolerance for larvae. These variations occurred at elevated salinities and temperatures seldom if ever encountered by F. grandis in culture or natural environments and are unlikely to affect larval survival in these settings. FA composition of eggs and tissues from spawning females suggested potential biosynthesis of LC-PUFAs from shorter-chain precursors in F. grandis. Results of this study suggest that F. grandis possesses physiological mechanisms allowing maintenance of reproductive function when subjected to dietary deficiencies in FAs generally considered essential for marine fishes.

Time-resolved infrared absorption studies of the solvent-dependent photochemistry of ClNO.

The photochemistry of nitrosyl chloride (ClNO) dissolved in cyclohexane is investigated using ultrafast time-resolved infrared (TRIR) spectroscopy. Following 266 nm photolysis, the photochemistry is measured by following changes in optical density at frequencies spanning the N═O stretch fundamental transition. A photoinduced depletion in optical density is observed consistent with the depletion of ground-state ClNO. The depletion in optical density remains constant out to ∼50 ps demonstrating that ClNO photodissociation is not followed by recombination of the Cl and NO photofragments. In addition, no evidence for the formation of the ClON photoisomer is observed. These results stand in contrast to previous studies in acetonitrile where ClNO photolysis is followed by geminate recombination of Cl and NO, and by the production of ClON. These differences in ClNO photochemistry are proposed to arise from the population of different excited-states caused by solvent dependence of the ground-state potential energy surface minimum along the Cl-N stretch coordinate. Solvent-dependent vibrational relaxation and differences in strength of the solvent cage are also proposed to contribute to the solvent-dependent photochemistry. Finally, these results are placed in the context of recent models of ClNO photochemistry and role of this compound in tropospheric ozone production.

Effects of low salinity media on growth, condition, and gill ion transporter expression in juvenile Gulf killifish, Fundulus grandis.

The Gulf killifish, Fundulus grandis, is a euryhaline teleost which has important ecological roles in the brackish-water marshes of its native range as well as commercial value as live bait for saltwater anglers. Effects of osmoregulation on growth, survival, and body condition at 0.5, 5.0, 8.0 and 12.0‰ salinity were studied in F. grandis juveniles during a 12-week trial. Relative expression of genes encoding the ion transport proteins Na(+)/K(+)-ATPase (NKA), Na(+)/K(+)/2Cl(-) cotransporter(NKCC1), and cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel was analyzed. At 0.5‰, F. grandis showed depressed growth, body condition, and survival relative to higher salinities. NKA relative expression was elevated at 7 days post-transfer but decreased at later time points in fish held at 0.5‰ while other salinities produced no such increase. NKCC1, the isoform associated with expulsion of ions in saltwater, was downregulated from week 1 to week 3 at 0.5‰ while CFTR relative expression produced no significant results across time or salinity. Our results suggest that Gulf killifish have physiological difficulties with osmoregulation at a salinity of 0.5‰ and that this leads to reduced growth performance and survival while salinities in the 5.0-12.0‰ are adequate for normal function.

Femtosecond pump-probe studies of actinic-wavelength dependence in aqueous chlorine dioxide photochemistry.

The actinic or photolysis-wavelength dependence of aqueous chlorine dioxide (OClO) photochemistry is investigated using femtosecond pump-probe spectroscopy. Following photoexcitation at 310, 335, and 410 nm the photoinduced evolution in optical density is measured from the UV to the near IR. Analysis of the optical-density evolution illustrates that the quantum yield for atomic chlorine production (Phi(Cl)) increases with actinic energy, with Phi(Cl)=0.16+/-0.02 for 410 nm excitation and increasing to 0.25+/-0.01 and 0.54+/-0.10 for 335 and 310 nm excitations, respectively. Consistent with previous studies, the production of Cl occurs through two channels, with one channel corresponding to prompt (<5 ps) Cl formation and the other corresponding to the thermal decomposition of ClOO formed by OClO photoisomerization. The partitioning between Cl production channels is dependent on actinic energy, with prompt Cl production enhanced with an increase in actinic energy. Limited evidence is found for enhanced ClO production with an increase in actinic energy. Stimulated emission and excited-state absorption features associated with OClO populating the optically prepared (2)A(2) surface decrease with an increase in actinic energy suggesting that the excited-state decay dynamics are also actinic energy dependent. The studies presented here provide detailed information on the actinic-wavelength dependence of OClO photochemistry in aqueous solution.

Femtosecond TRIR studies of ClNO photochemistry in solution: evidence for photoisomerization and geminate recombination.

The photochemistry of nitrosyl chloride (ClNO) in the solution phase is investigated using Fourier transform infrared (FTIR) and ultrafast time-resolved infrared (TRIR) spectroscopies. The NO-stretch fundamental transition for ClNO dissolved in cyclohexane, carbon tetrachloride, chloroform, dichloromethane, and acetonitrile is measured, with the frequency and line width of this transition demonstrating a strong dependence on solvent polarity. Following the photolysis of ClNO dissolved in acetonitrile at 266 nm, the subsequent optical-density evolution across the entire width of the NO-stretch fundamental is measured. Analysis of the optical-density evolution demonstrates that geminate recombination of the primary photofragments resulting in the reformation of ground state ClNO occurs with a quantum yield of 0.54 +/- 0.06. In addition, an increase in optical density is observed at 1860 cm(-1) that is assigned to the NO-stretch fundamental transition of the photoisomer, ClON, having a formation quantum yield of 0.07 +/- 0.02. This work represents the first definitive observation of ClNO photoisomerization in solution. Finally, essentially no evidence is observed for significant vibrational excitation of the NO fragment following photodissociation, in marked contrast to the behavior observed in the gas phase. An environment-dependent dissociation scheme is proposed in which the interplay between solvent polarity and the location of the ground state potential-energy-surface minimum along the Cl-N coordinate provides for the optical preparation of different excited states thereby affecting the extent of NO vibrational excitation following photolysis.