RESUMO
INTRODUCTION: This systematic review delves into the impact of social media on self-perception and the escalating interest in clinical aesthetic procedures, proposing that social media significantly influences beauty standards and increases demand for aesthetic enhancements. METHOD: Following PRISMA guidelines, a mixed-method analysis of 34 articles was conducted, sourced from various databases, focusing on social media's psychological effects on clinical aesthetics decisions. The studies encompassed a broad spectrum, including qualitative, quantitative, and mixed methodologies, reflecting diverse geographical and cultural perspectives. RESULTS: The quantitative analysis demonstrated a strong positive correlation between social media usage and the consideration of aesthetic procedures (r=0.45, p<0.001), indicating a significant impact. Specific findings included a large effect size (Cohen's d=0.8) for the relationship between time spent on social media and the desire for aesthetic enhancements. Individuals spending more than 3 hours per day on social media platforms were twice as likely to consider aesthetic procedures compared to those with less usage, with a 95% confidence interval indicating robustness in these findings. CONCLUSION: Confirming the reinforcing effect of social media on aesthetic decision-making, this study highlights the complex interplay between digital media exposure, altered self-perception, and the increased inclination towards aesthetic procedures. It suggests a critical need for practitioners to carefully navigate the digital influence on patient's desires, reinforcing the significance of understanding psychological motivations and societal pressures in clinical aesthetics. This comprehensive analysis offers pivotal insights for clinical practice and ongoing research into social media's role in contemporary beauty standards. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
RESUMO
BACKGROUND: Aesthetic medicine has evolved significantly, accommodating diverse demographics and motivations influenced by societal shifts and technological advancements. The IMPACT (integrative multigenerational psychological analysis for cosmetic treatment) study refines patient archetypes, integrating psychological theories to tailor treatments, especially for younger demographics and LGBTQIA + communities. METHODS: This cross-sectional study utilized a comprehensive, validated survey with a Cronbach's alpha of 0.89 and a Content Validity Index (CVI) of 0.92, distributed across a globally diverse, generationally stratified sample. Techniques like regression analysis, ANOVA, Bayesian modelling, and factor analysis were employed to analyse the data, focusing on developing nuanced patient archetypes. RESULTS: Among 5645 participants, 5340 complete responses highlighted significant generational differences in aesthetic preferences. Millennials showed a strong preference for non-invasive procedures (ß = 0.65, p < 0.001). ANOVA results confirmed significant variances across generations [F (3, 5118) = 157.6, p < 0.001], with post-hoc analyses delineating specific inter-group differences. Bayesian modelling provided insights into the probability of non-invasive preferences among younger cohorts at over 92% certainty. Factor analysis revealed key dimensions such as 'Generational Influence' and 'Technological Adoption,' which helped in defining archetypes including Dynamic Self-Identity, Digital Native, Stability Seeker, Classic Conservatism, and Holistic Health, collectively explaining up to 78% of the variance in responses. CONCLUSION: The IMPACT study underscores the influence of generational identity and digital exposure on aesthetic preferences, advocating for personalized, archetype-based treatment approaches. This aligns with enhancing patient satisfaction and treatment outcomes, promoting an adaptive aesthetic medicine practice that meets the evolving needs of modern patients. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
RESUMO
INTRODUCTION: The study investigates the impact of social media reviews and brand identity on consumer preferences in the non-surgical aesthetics products across different generations. It highlights the evolving landscape of aesthetic medicine and surgery, driven by technological advancements and a cultural shift towards individual well-being. The research aims to explore the interplay between generational preferences, the influence of social media, and the role of brand identity in shaping consumer decisions. METHODS: A cross-sectional study design was employed, with a sample size of > 5000 participants stratified across various generational cohorts. The study utilized an online questionnaire to capture both quantitative and qualitative insights into consumer behaviour, with statistical analysis performed to identify patterns and relationships. RESULTS: Analysis of 5850 responses revealed distinct generational preferences and behaviours. Social media engagement varied significantly across generations, with younger cohorts placing a higher emphasis on online reviews. The study also found that brand identity's influence is diminishing in decision-making processes, with consumers increasingly relying on peer reviews and social media content. CONCLUSION: The findings highlight a pivotal shift in the non-surgical aesthetics consumer market, emphasizing the growing importance of social media and peer reviews over traditional brand identities. Importantly, the study underscores the critical need for integrating patient safety and evidence-based practice within marketing strategies. As consumer preferences evolve towards valuing transparency and authenticity, non-surgical aesthetics providers must prioritize these elements, ensuring that their services are not only appealing but also grounded in safety and scientific validity. LEVEL OF EVIDENCE IV: "This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 ."
RESUMO
INTRODUCTION: Exosomes, diminutive extracellular vesicles, are integral to intercellular communication, harbouring potential for applications in regenerative medicine and aesthetic interventions. The field, however, grapples with the complexities of harmonising exosome characterisation protocols and safeguarding therapeutic integrity. METHODOLOGY: In this scholarly overview, systematic adherence to the Cochrane Collaboration and Preferred Reporting Items for Overviews of Reviews guidelines was observed, scrutinising the congruence of exosome-related therapies with the Minimal Information for Studies of Extracellular Vesicles standards delineated by the International Society for Extracellular Vesicles, alongside criteria set forth by the International Society for Cell Therapy and the International Society for Stem Cell Research. A meticulous search strategy spanning databases such as PubMed, Scopus, Web of Science, EMBASE, and Cochrane database was employed to encapsulate studies pertinent to the isolation, characterisation, and functional assessment of exosomes. RESULTS: The initial search yielded 225 articles, of which 17 systematic reviews were selected based on predefined criteria, encompassing 556 primary studies. Notwithstanding the acknowledged therapeutic promise of exosome modalities, the synthesis illuminated a prevalent deficiency in adherence to established reporting and experimental benchmarks, notably in exosome source characterisation and bioactive constituent delineation. A critical appraisal employing the AMSTAR-2 tool underscored a pervasive shortfall in methodological rigour. CONCLUSION: This review accentuates the imperative for stringent methodological standardisation within exosome research to fortify the validity and reproducibility of empirical findings. Amidst the burgeoning therapeutic optimism, the discipline must rectify methodological disparities and comply with regulatory mandates, ensuring the ethically sound and scientifically robust advancement of exosome-based therapeutic modalities. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
RESUMO
BACKGROUND: Regenerative aesthetics claims to enhance cosmetic outcomes through advanced biological interventions like Stem cell and Exosome therapy, Polydeoxyribonucleotide (PDRN), Photobiomodulation, bioactive peptides and treatment for cellular senescence yet lacks substantial scientific and regulatory validation. OBJECTIVE: To evaluate the scientific and clinical foundations of regenerative medicine techniques in non-surgical aesthetics and assess the legitimacy of regenerative aesthetics as a medical specialty. METHODS: A systematic review was conducted according to PRISMA guidelines, searching databases including PubMed, Scopus, and Web of Science for studies published in the last ten years. We included 19 studies, comprising 14 randomized controlled trials (RCTs) and 5 prospective studies, focusing on interventions that purportedly use regenerative medicine principles in aesthetic applications. RESULTS: The review highlights a prevalent gap in molecular and clinical evidence supporting the efficacy and safety of regenerative aesthetics. Despite the robust design of the included RCTs and prospective studies, there remains a significant lack of consistent, high-quality evidence proving the effectiveness of these interventions. Issues such as inadequate reporting, unclear molecular mechanisms, and absence of long-term safety data were common. CONCLUSION: The field of regenerative aesthetics lacks the necessary scientific rigour and regulatory compliance to be recognized as a legitimate medical specialty. This review underscores the need for stringent scientific validation and regulatory oversight to ensure patient safety and treatment efficacy before these techniques can be recommended for clinical use. LEVEL OF EVIDENCE II: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
RESUMO
The bio-accumulation of mycosporine-like amino acids (MAAs) is common in planktonic copepods that inhabit environments exposed to high levels of solar radiation. MAAs accumulation in copepods can be affected both by extrinsic (environmental) and intrinsic factors (local adaptation, genotype, etc.). Laboratory experiments were performed to study the bio-accumulation of MAAs in two geographically-isolated populations of Boeckella gracilipes from a mountain and a piedmont lake of North Patagonia. We performed two series of 10-day incubations of B. gracilipes from the different lakes applying two radiation conditions (PAR + UVR and darkness), at five different temperatures (5 to 20 °C) and providing a MAA-free flagellate as food. We assumed that differences in final MAAs concentrations between copepod populations should be exclusively due to environmental factors, and that any difference in the patterns of MAAs accumulation should exclusively arise from differences in MAAs concentration at the time of collection. MAAs concentration was three fold higher in B. gracilipes from Lake Verde than in copepods from the Lake Morenito. The MAAs suite was dominated (â¼90%) by a combination of porphyra-334 and mycosporine-glycine in copepods from Lake Verde, and porphyra-334 and MAA-332 in those from Lake Morenito. Two exclusive MAA compounds were identified, mycosporine-glycine in copepods from Lake Verde and shinorine in the copepod population from Lake Morenito. Laboratory experiments showed that: (i) exposure to PAR + UVR stimulated the accumulation of MAAs in both copepod populations; (ii) temperature affected the response of MAAs and, remarkably, low temperatures stimulated MAAs accumulation even in dark incubations, (iii) the response to radiation and temperature in MAAs accumulation was more pronounced in the population with low initial MAAs than in the population with high initial MAAs concentrations. The differences in intrinsic factors between B. gracilipes populations, such as local adaptation to contrasting UV and temperature scenarios, among others, appear to play an important role in determining levels and patterns of MAAs accumulation in B. gracilipes.
Assuntos
Copépodes/metabolismo , Cicloexanóis/metabolismo , Cicloexanonas/metabolismo , Cicloexilaminas/metabolismo , Glicina/análogos & derivados , Temperatura , Raios Ultravioleta , Animais , Escuridão , Meio Ambiente , Alimentos , Glicina/metabolismo , Lagos , América do Sul , Especificidade da EspécieRESUMO
Background: Botulinum toxin A (BTxA) has gained popularity as a nonsurgical aesthetic treatment for skin rejuvenation. However, previous studies on intradermal BTxA have shown inconsistent results. This systematic review and meta-analysis with trial sequential analysis aimed to assess the efficacy and safety of intradermal BTxA for facial rejuvenation. Methods: Following PRISMA guidelines, a comprehensive search was conducted in various databases from January 2008 to March 2023. Outcome measures included sebum production, pore size, skin hydration, skin texture, erythema index, facial wrinkles, and facelift. Eligible studies included human-based clinical trials and prospective cohort studies published in English, focusing on healthy populations requiring facial rejuvenation. Two authors independently screened the titles and abstracts, followed by a full-text review to determine study eligibility. Data extraction and quality assessment were performed by two authors using predefined criteria. Results: Ten studies met the inclusion criteria, including five randomized controlled trials and five prospective cohort studies with 153 participants. Studies revealed positive effects of intradermal BTxA on various outcome measures related to facial rejuvenation. These effects included improvements in sebum production, pore size, erythema index, facial wrinkles, skin texture and elasticity, and overall facelift but not skin hydration. All failed to reach the required information size in the trial sequential analysis. Conclusions: Findings suggest positive outcomes in multiple attributes of skin quality and facial rejuvenation. However, more high-quality research is needed to establish definitive conclusions. These findings contribute to the evidence base for nonsurgical aesthetic treatments, emphasizing the importance of ongoing research in this field.
RESUMO
Kelp forests, among the most productive ecosystems on Earth, cover large areas of the South Atlantic coast. Sediment heterotrophic bacteria have a pivotal role in the degradation of kelp biomass, however, the response of sediment microbial communities to periodic kelp biomass inputs is mostly unknown. Here, we show that kelp biomass induced rapid changes in overlying water chemistry and shifts in sediment microbial communities, which differed in the experimental systems containing Macrocystis pyrifera (M) and Undaria pinnatifida (U) with sediments of the respective regions. We observed results compatible with the degradation of labile, high molecular weight compounds into smaller and more refractory compounds towards the end of the incubations. The capability of microbial communities to degrade alginate, the major component of kelp cell walls, significantly increased with respect to controls after kelp biomass addition (Absorbance at 235 nm 1.2 ± 0.3 and 1.0 ± 0.2 for M and U, respectively, controls <0.2, t = 4 days). Shifts in microbial community structure (based on 16S rRNA gene amplicon sequencing) were tightly related to the kelp treatment and, to a lesser extent, to the sediment provenance (Principal Coordinates Analysis, 80 % of variation explained in the first two axes). Dissolved oxygen, pH, salinity, alginolytic potential, Absorbance at 235 and 600 nm, total N, total C, and SUVA index correlated significantly with community structure. Differentially abundant populations between kelp-amended treatments and controls included members of the Flavobacteriia class (Algibacter and Polaribacter), and Gammaproteobacteria (Psychromonas and Marinomonas), among others. Metagenomes of M and U-amended sediments contained sequences from 18 of the 19 enzyme families related to alginate or fucoidan degradation. Specific taxonomic groups were associated with enzyme classes targeting different substrates, suggesting niche differentiation. This work expands our knowledge on the patterns of microbial assemblages from intertidal sediments in response to kelp biomass inputs.
Assuntos
Kelp , Macrocystis , Microbiota , Ecossistema , RNA Ribossômico 16S , Microbiota/fisiologia , AlginatosRESUMO
Phytoplankton communities are major primary producers in the aquatic realm and are responsible for shaping aquatic ecosystems. The dynamics of algal blooms could be determined by a succession of variable taxonomic groups, which are altered based on complex environmental factors such as nutrient availability and hydraulic factors. In-river structures potentially increase the occurrence of harmful algal blooms (HABs) by increasing water residence time and deteriorating water quality. How flowing water stimulates cell growth and affects the population dynamics of phytoplankton communities is a prioritized question that needs to be addressed for water management tactics. The goal of this study was to determine if an interaction between water flow and water chemistry is present, furthermore, to determine the relationship among phytoplankton community successions in the Caloosahatchee River, a subtropical river strongly influenced by human-controlled water discharge patterns from Lake Okeechobee. Particularly we focused on how phytoplankton community shifts influence the natural abundance of hydrogen peroxide, the most stable reactive oxygen species and a byproduct of oxidative photosynthesis. High-throughput amplicon sequencing using universal primers amplify 23S rRNA gene in cyanobacteria and eukaryotic algal plastids revealed that Synechococcus and Cyanobium were the dominant cyanobacterial genera and their relative abundance ranged between 19.5 and 95.3% of the whole community throughout the monitoring period. Their relative abundance declined when the water discharge increased. On the contrary, the relative abundance of eukaryotic algae sharply increased after water discharge increased. As water temperature increased in May, initially dominant Dolichospermum decreased as Microcystis increased. When Microcystis declined other filamentous cyanobacteria such as Geitlerinema, Pseudanabaena, and Prochlorothreix increased in their relative abundances. Interestingly, a peak of extracellular hydrogen peroxide was observed when Dolichospermum dominance was ended, and M. aeruginosa numbers increased. Overall, phytoplankton communities were strongly impacted by human-induced water discharge patterns.
Assuntos
Microcystis , Synechococcus , Humanos , Fitoplâncton , Peróxido de Hidrogênio , Rios/microbiologia , Ecossistema , Florida , Proliferação Nociva de AlgasRESUMO
Undaria pinnatifida is a brown algae native to Asia that has settled in various regions worldwide, periodically contributing with large quantities of C and nutrients during its annual cycle. In this work, we analyzed a coastal site in Patagonia (Argentina) that has been colonized for three decades by U. pinnatifida, focusing on associated microbial communities in three different compartments. An important influence of algae was observed in seawater, especially in the bottom of the algal forest during the austral summer (January) at the moment of greater biomass release. This was evidenced by changes in DOC concentration and its quality indicators (higher Freshness and lower Humification index) and higher DIC. Although maximum values of NH4 and PO4 were observed in January, bottom water samples had lower concentrations than surface water, suggesting nutrient consumption by bacteria during algal DOM release. Concomitantly, bacterial abundance peaked, reaching 4.68 ± 1.33 × 105 cells mL -1 (January), showing also higher capability of degrading alginate, a major component of brown algae cell walls. Microbial community structure was influenced by sampling date, season, sampling zone (surface or bottom), and environmental factors (temperature, salinity, pH, dissolved oxygen, nutrients). Samples of epiphytic biofilms showed a distinct community structure compared to seawater, lower diversity, and remarkably high alginolytic capability, suggesting adaptation to degrade algal biomass. A high microdiversity of populations of the genus Leucothrix (Gammaproteobacteria, Thiotrichales) that accounted for a large fraction of epiphytic communities was observed, and changed over time. Epiphytic assemblages shared more taxa with bottom than with surface seawater assemblages, indicating a certain level of exchange between communities in the forest surroundings. This work provides insight into the impact of U. pinnatifida decay on seawater quality, and the role of microbial communities on adapting to massive biomass inputs through rapid DOM turnover.
Assuntos
Kelp , Undaria , Bactérias/metabolismo , Chile , Água do Mar/química , Água/metabolismoRESUMO
Climate change is rapidly driving global biodiversity declines. How wetland macroinvertebrate assemblages are responding is unclear, a concern given their vital function in these ecosystems. Using a data set from 769 minimally impacted depressional wetlands across the globe (467 temporary and 302 permanent), we evaluated how temperature and precipitation (average, range, variability) affects the richness and beta diversity of 144 macroinvertebrate families. To test the effects of climatic predictors on macroinvertebrate diversity, we fitted generalized additive mixed-effects models (GAMM) for family richness and generalized dissimilarity models (GDMs) for total beta diversity. We found non-linear relationships between family richness, beta diversity, and climate. Maximum temperature was the main climatic driver of wetland macroinvertebrate richness and beta diversity, but precipitation seasonality was also important. Assemblage responses to climatic variables also depended on wetland water permanency. Permanent wetlands from warmer regions had higher family richness than temporary wetlands. Interestingly, wetlands in cooler and dry-warm regions had the lowest taxonomic richness, but both kinds of wetlands supported unique assemblages. Our study suggests that climate change will have multiple effects on wetlands and their macroinvertebrate diversity, mostly via increases in maximum temperature, but also through changes in patterns of precipitation. The most vulnerable wetlands to climate change are likely those located in warm-dry regions, where entire macroinvertebrate assemblages would be extirpated. Montane and high-latitude wetlands (i.e., cooler regions) are also vulnerable to climate change, but we do not expect entire extirpations at the family level.
Assuntos
Biodiversidade , Invertebrados , Áreas Alagadas , Animais , Mudança ClimáticaRESUMO
Hydrogen peroxide (H2O2) is a ubiquitous reactive oxygen species (ROS) in aquatic systems and is produced mainly in surface water by the interaction of ultraviolet radiation (UVR) and natural dissolved organic carbon (DOC). Andean Patagonian lakes are ultraoligotrophic, clear systems with extended photic zones (~40 m), and are exposed to challenging UVR levels due to their lati-altitudinal situation and extremely low DOC levels. This investigation describes the seasonal levels of H2O2 in relation to DOC quality in the water column of lakes Moreno East (ME) and Moreno West (MW), two deep (ca. 100 m), ultraoligotrophic, low-DOC (<0.7 mg L-1) systems of Andean Patagonia. H2O2 concentrations recorded in the lakes were below 60 nM, ranging from ~3 to ~60 nM in Lake ME and from ~5 to ~35 nM in Lake MW. In most of the samples of both lakes, the H2O2 levels were higher in the photic zone (surface to 30-40 m) than the aphotic zone (from 30-40 m to 90-100 m), particularly in summer samples. Laboratory experiments evaluated the abiotic (photochemical) and biotic (microbial) production of H2O2 in seasonal (summer, autumn) samples which varied DOM quality due to lake (ME, MW) and depth (photic and aphotic lake layers) provenance. Abiotic and biotic production of H2O2 attained higher levels in summer samples from the photic zones of both lakes. Humic DOM from deep layers (particularly from summer samples) was more susceptible to both photo- and bio-degradation than DOM from upper lake layers, which was characterized by stronger signs of degradation and progress in diagenesis.
Assuntos
Lagos , Poluentes Químicos da Água/análise , Carbono , Peróxido de Hidrogênio , Raios UltravioletaRESUMO
Hydrological connectivity between terrestrial and aquatic systems is influenced by landscape features. Topography, vegetation cover and type, lake morphometry and climate (seasonality, precipitation) drive the timing, concentration and quality of allochthonous dissolved organic matter (DOM) inputs to lakes, influencing lake metabolism. The impact of climate changes on terrestrial-aquatic linkages depends on regional trends and ecosystems properties. We examined how landscape heterogeneity affects lake DOM in pristine temperate headwater lakes located in sharp bioclimatic gradients at the leeward side of the southern Andes (Patagonia, Argentina), and predicted their potential responses to forecasted changes in regional climate. We assessed DOM properties of deep and shallow lakes spotted along precipitation and altitudinal gradients which reflect on vegetation heterogeneity. Lake DOM (concentration, and chromophoric and fluorescent properties) was related to terrestrial bioclimatic conditions, addressing also DOM bio- and photodegradation processes. Co-effects of climate and vegetation determined the quantity and quality of allochthonous DOM inputs. Higher terrestrial signs showed up at the wettest extreme of the gradient and during the rainy season, being attributable to higher hydrological land-water connectivity, and dense vegetation cover. Under drier conditions, DOM displayed higher photobleaching signs at spatial and temporal scales. The ratio between non-humic and terrestrial humic substances indicated that DOM biodegradation dominates in shallow forested lakes and photodegradation prevails in deep ones, whereas coupled photo- and biological processing shaped the DOM pool of high altitude lakes. Overall, DOM optical metrics captured landscape heterogeneity. Under the forecasted climate changes for Patagonia (decreasing precipitation and increasing temperature), piedmont lakes may experience lower hydrological connectivity, lower terrestrial inputs and, enhanced photobleaching usually associated with longer water residence time. In high altitude lakes, terrestrial DOM inputs are expected to increase due to the upward expansion of native deciduous forests, thus becoming more similar to lakes located lower in the landscape.
Assuntos
Monitoramento Ambiental , Substâncias Húmicas/análise , Lagos/química , Argentina , Espectrometria de FluorescênciaRESUMO
Fluvial networks transport a substantial fraction of the terrestrial production, contributing to the global carbon cycle and being shaped by hydrologic, natural and anthropogenic factors. In this investigation, four Andean Patagonian oligotrophic streams connecting a forested catchment (~125km(2)) and draining to a double-basin large and deep lake (Lake Moreno complex, Northwestern Patagonia), were surveyed to analyze the dynamics of the allochthonous subsidy. The results of a 30month survey showed that the catchment supplies nutrients and dissolved organic matter (DOM) to the streams. The eruption of the Puyehue-Cordón Caulle at the beginning of the study overlapped with seasonal precipitation events. The largest terrestrial input was timed with precipitation which increased particulate materials, nutrients and DOM through enhanced runoff. Baseline suspended solids and nutrients were very low in all the streams (suspended solids: ~1mg/L; total nitrogen: ~0.02mg/L; total phosphorus: ~5µg/L), increasing several fold with runoff. Baseline dissolved organic carbon concentrations (DOC) ranged between 0.15 and 1mg/L peaking up to three-fold. Chromophoric and fluorescent analyses characterized the DOM as of large molecular weight and high aromaticity. Parallel factor modeling (PARAFAC) of DOM fluorescence matrices revealed three components of terrestrial origin, with certain degree of microbial processing: C1 and C2 (terrestrial humic-like compounds) and C3 (protein-like and pigment derived compounds). Seasonal changes in MOD quality represent different breakdown stages of the allochthonous DOM. Our survey allowed us to record and discuss the effects of the Puyehue-Cordón Caulle eruption, showing that due to the high slopes, high current and discharge of the streams the volcanic material was rapidly exported to the Moreno Lake complex. Overall, this survey underscores the magnitude and timing of the allochthonous input revealing the terrestrial subsidy to food webs in Patagonian freshwaters, which are among the most oligotrophic systems of the world.
Assuntos
Clima , Monitoramento Ambiental , Substâncias Húmicas , Rios/química , Poluentes Químicos da Água/análise , Argentina , Carbono/análise , Fluorescência , Cadeia Alimentar , Nitrogênio/análise , Fósforo/análiseRESUMO
Mycosporine-like amino acids (MAAs) are ubiquitous photoprotective compounds in aquatic environments. MAAs are synthesized by a wide variety of organisms (i.e. bacteria, fungi and algae) and their production is photoinducible by ultraviolet radiation (UVR) (280-400 nm) and/or photosynthetically active radiation (400-750 nm). Most animals however, are unable to synthesize MAAs and must acquire these compounds through their diet or from symbiotic organisms. In this paper, we investigate the possible sources of MAAs and factors (temperature and initial MAA concentration) that may affect their bioaccumulation in freshwater copepods. We found that MAA accumulation may occur even if the copepods are cultured on a MAA-free diet. In addition, we found that the bacteriostatic antibiotic, chloramphenicol, inhibits the bioaccumulation of MAAs. These two pieces of evidence suggest that the source of MAAs in these copepods may be prokaryotic organisms in close association with the animals. The two factors investigated in this study, temperature and initial MAA concentrations, were found to affect the rates at which MAAs are accumulated. Temperature had positive effects on both uptake and elimination rates. On the other hand, the rate of uptake decreased at the highest assayed initial MAA concentration, probably because the concentration of MAAs was already close to saturation.