Facultad de Ciencias del Mar y Recursos Biológicos

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A genome-based phylogeny for Mollusca is concordant with fossils and morphology
(American Association for the Advancement of Science, 2025) Chen, Zeyuan; Baeza, J. Antonio; Chen, Chong; Gonzalez, Maria Teresa; Gonzalez, Vanessa Liz; Greve, Carola; Kocot, Kevin M; Arbizu, Pedro Martinez; Moles, Juan; Schell, Tilman; Schwabe, Enrico; Sun, Jin; Wong, Nur Leena W. S; Yap-Chiongco, Meghan; Sigwart, Julia D
Extreme morphological disparity within Mollusca has long confounded efforts to reconstruct a stable backbone phylogeny for the phylum. Familiar molluscan groups-gastropods, bivalves, and cephalopods-each represent a diverse radiation with myriad morphological, ecological, and behavioral adaptations. The phylum further encompasses many more unfamiliar experiments in animal body-plan evolution. In this work, we reconstructed the phylogeny for living Mollusca on the basis of metazoan BUSCO (Benchmarking Universal Single-Copy Orthologs) genes extracted from 77 (13 new) genomes, including multiple members of all eight classes with two high-quality genome assemblies for monoplacophorans. Our analyses confirm a phylogeny proposed from morphology and show widespread genomic variation. The flexibility of the molluscan genome likely explains both historic challenges with their genomes and their evolutionary success.
A New Species of Encotyllabe Diesing, 1850 (Monopisthocotylea: Capsalidae), from the Pharyngeal Plates of Sciaena deliciosa (Tschudi, 1846) (Eupercaria: Sciaenidae) in Peru, with Notes on the Nomenclatural Status of E. callaoensis Tantaleán, 1974
(MDPI, 2025) Huerta, Andrés; Villena, Carlos; Ramos, Moises; Rojas, Joana; Milla, Kely; Mondragón-Martiínez, Aarón; Ñacari, Luis; Cruces, Celso Luis; Chero, Jhon Darly
A new species of Encotyllabe Diesing, 1850 (Monopisthocotylea: Capsalidae), Encotyllabe tantaliani n. sp., is described from the pharyngeal plates of the Lorna drum, Sciaena deliciosa (Tschudi, 1846) (Eupercaria: Sciaenidae), collected from two localities along the Peruvian coast. This new species was originally proposed as E. callaoensis Tantaleán, 1974, in an unpublished doctoral thesis, and is herein recognized as a nomen nudum under the International Code of Zoological Nomenclature (ICZN). Encotyllabe tantaliani n. sp. is distinguished from all known congeners by the following combination of morphological features: (1) an anteriorly tapering body proper, (2) slightly lobed testes markedly larger than the ovary, (3) vitelline follicles beginning at the level of the male copulatory organ (MCO) and absent from the regions of the reproductive organs, (4) a genital pore positioned posterolateral to the pharynx, and (5) an oblong-shaped MCO. Phylogenetic analysis based on cox1 sequence places E. tantaliani n. sp. in a clade with Encotyllabe percussa Morales-Ávila, Jufaili & Ogawa, 2024, a parasite of Lethrinus nebulosus (Forsskål, 1775) (Eupercaria: Lethrinidae) from the Arabian Gulf. Pairwise genetic distances support the distinctiveness of the new species from its closest congeners. Encotyllabe tantaliani n. sp. represents the first species of the genus described from a host belonging to the Sciaenidae host.
Advocating microbial diversity conservation in Antarctica
(Springer Nature, 2025) Zucconi, Laura; Fierro-Vásquez, Natalia; Antunes, André; Gonçalves Bendia, Amanda; Lavín, Paris; González-Aravena, Marcelo; Kumar Sani, Rajesh; Banerjee, Aparna
Antarctica, a seemingly barren and icy wilderness, is home to a diverse array of microbial life that playsa critical role in sustaining its ecosystems. These resilient microorganisms drive nutrient cycling andcarbon sequestration, but their function in global processes remains unclear. This pristineenvironment faces mounting threats from human activities, climate change, and increasing tourism.Contaminants, non-native species, and microplastics are increasingly reaching even the most remoteregions, disrupting delicate microbial communities existing for millions of years. Antarcticmicroorganisms are not only ecologically significant but also valuable for biotechnologicaladvancements, making their conservation imperative. Climate change exacerbates these threats,altering microbial habitats and promoting shifts in community structure. Tourism growth, thoughbeneficial for education and economic reasons, poses significant challenges through biological andchemical contamination. Despite efforts under the Antarctic Treaty System to protect the region, thereis a critical need for enhanced measures specifically targeting microbial conservation. This articleunderscores the importance of conserving Antarctic microbial diversity. It highlights the intricatemicrobial ecosystems and the urgency of implementing strategies such as stringent biosecuritymeasures, sustainable tourism practices, and comprehensive monitoring programs. Additionally,fostering international collaboration and research initiatives is vital for understanding and designingstrategies to mitigate the impacts of environmental changes on microbial life. By prioritizing microbialconservation in policy frameworks and strengthening global cooperation, we can safeguard theseunique ecosystems and ensure their resilience for future generations
Assessing the food web structure of the mesozooplankton community in the highly variable coastal upwelling system of the southeast Pacific
(Elsevier, 2025) Cabrera-Nunez, Susana; Fernandez-Urruzola, Igor; Bode, Antonio; Hernandez-Trujillo, Sergio; Hidalgo, Pamela; Escribano, Ruben
Zooplankton are a key component in the food web of highly productive coastal upwelling systems linking primary producers to higher trophic levels. However, the complex taxonomy, wide size spectrum, and diverse trophic behaviors of zooplankton make it challenging to characterize their food web structure. This study proposes a Trophic Behavior Index (TBI) to assess the trophic structure of zooplankton and test the hypothesis that key biological attributes such as body size, diel vertical migration (DVM) behavior and trophic interactions, rather than environmental factors, primarily shape the food web dynamics of mesozooplankton communities. To this end, we analyzed depth-stratified daytime and nighttime samples of mesozooplankton collected from the upper 900 m at three oceanographically contrasting stations in the Southeast Pacific upwelling system. Vertical gradients in temperature, chlorophyll-a and dissolved oxygen were examined in relation to zooplankton abundance and composition, their DVM behavior, biomass size spectra and trophic position. The proposed TBI was constructed from zooplankton body size assessed by automated image analysis, DVM amplitude and trophic position of taxonomic groups derived from nitrogen stable isotope composition. This index was then compared across environmental conditions, allowing the classification of mesozooplankton into four major trophic functional groups: low predators (primary consumers), moderate predators, strong predators and top predators (very strong predators). Variability in oceanographic conditions influenced the zooplankton community composition and size spectrum; however, our findings suggest that zooplankton body size, DVM behavior and trophic position are the primary determinants of trophic structure. This is reflected in the relative abundance of functional groups, with strong and very strong predators prevailing in offshore areas, whereas the coastal zone was dominated by primary consumers and moderate predators. Overall, our findings support the TBI as a robust community descriptor of zooplankton trophic structure across highly variable oceanographic settings.
Biogeographic Insights Into the Late Miocene Diversification of the Giant Deep-Ocean Amphipod Eurythenes
(Wiley, 2025) Gonzalez, Carolina E; Weston, Johanna N. J; Rivera, Reinaldo; Oliva, Marcelo; Escribano, Ruben; Ulloa, Osvaldo
Mechanisms driving the spatial and temporal patterns of species distribution in the Earth's largest habitat, the deep ocean, remainlargely enigmatic. The late Miocene to the Pliocene (~23–2.58 Ma) is a period that was marked by significant geological, climatic,and oceanographic changes. This transitional period spurred widespread species diversification, particularly among widely dis-tributed benthic scavengers, such as amphipods. Here, we take step toward understanding the long-term evolutionary processesof amphipod colonization and diversification in the deep ocean by focusing on the model genus Eurythenes S. I. Smith in Scudder,1882. These large-bodied scavengers play key roles in benthic communities. We constructed a time-calibrated phylogeny usingtwo mitochondrial DNA genes by analyzing publicly available data on 14 species of Eurythenes across a global depth range from839 to 8081 m. The resulting phylogenetic tree reveals a diverse clade, with a common ancestor originating around 11.81 Ma. Agradual increase in the effective population size of Eurythenes was observed, particularly during the Pliocene (~4 Ma). The netdiversification rate remained almost constant, with slight increases between the Miocene and Pliocene (~8–4 Ma), and most newspecies appeared during the latter period. Additionally, reconstruction of the ancestral area suggested that the common ancestorof Eurythenes had a global distribution. A combination of dispersal and sympatric processes, along with environmental factors,such as changes in ocean temperature and sea level, contributed to the present biogeographic distribution of these species. Ourfindings highlight the importance of historical events, such as plate tectonics and changes in deep-water circulation, in drivingthe rapid speciation of Eurythenes and underscore their essential role in shaping deep-ocean biodiversity
Biophysical performance indicators for secondary resources reveal positive effects at the community level in La Rinconada Marine Reserve (Antofagasta, Chile), SE Pacific Ocean
(Pontificia Universidad Católica de Valparaíso, 2025) Avendano, Miguel; Cantillanez, Marcela
. Direct evaluations of the main resource Argopecten purpuratus and its accompanying benthic fauna developed between 1999 and 2013 in La Rinconada Marine Reserve (Antofagasta, northern Chile) confirmed the presence of two subsystems made up of different species that cohabit with the principal resource (designated SS1 and SS2). SS1 has a medium and fine sand substrate with a coverage of over 80% at the center of the red algae Rhodymenia corallina. In addition to the primary resource, the scallop A. purpuratus, we also found secondary resources such as Thaisella chocolata, Romaleon setosum, and, under ENSO conditions, Octopus mimus recruits. In SS2, which runs parallel to the coastline, coarser substrates are observed, mainly shells and quartzite gravel mixed with fine and medium sand areas occupied by the bivalves Transennella pannosa and Tagelus dombeii. Our results show that anthropogenic activities have not affected the abundance and size structure of secondary resources in SS1 and density and size structure in SS2, evidencing a permanent pre-recruitment of organisms. The information generated in this study can complement the current criteria applied to assess the performance of this reserve by accounting for the state of the main commercial resource of interest (A. purpuratus). We also discuss the benefits of a more integrative methodology that evaluates the benthic community and the ecosystem based on a conservation and management approach. An inventory of the recorded species in the marine reserve is also provided for the first time and may constitute a baseline for future studies
Blowin’ in the Wind: Mapping the Dispersion of Metal(loid)s From Atacama Mining
(Advancing Earth and Space Sciences, 2024) Zanetta-Colombo, Nicolás, C.; Manzano, Carlos A.; Brombierstäudl, Dragmar; Fleming, Zoë L.; Gayo, Eugenia M.; Rubinos, David A.; Jerez, Óscar; Valdés, Jorge; Prieto, Manuel; Nüsser, Marcus
The Atacama Desert's naturally elevated metal(loid)s pose a unique challenge for assessing the environmental impact of mining, particularly for indigenous communities residing in these areas. This study investigates how copper mining influences the dispersion of these elements in the wind-transportable fraction (<75 mu m) of surface sediments across an 80 km radius. We employed a multi-pronged approach, utilizing spatial modeling to map element distributions, exponential decay analysis to quantify concentration decline with distance, regime shift modeling to identify dispersion pattern variations, and pollution assessment to evaluate impact. Our results reveal significant mining-driven increases in surface concentrations of copper (Cu), molybdenum (Mo), and arsenic (As). Notably, within the first 20 km, concentrations peaked at 1,016 mg kg(-1) for Cu, 31 mg kg(-1) for Mo, and a remarkable 165 mg kg(-1) for As. Cu and Mo displayed significant dispersion, extending up to 50 km from the source. However, As exhibited the most extensive reach, traveling up to 70 km downwind, highlighting the far-reaching ecological footprint of mining operations. Mineralogical analyses corroborated these findings, identifying mining-related minerals in surface sediments far beyond the immediate mining area. Although pollution indices based on the proposed Local Geochemical Background reveal significant contamination across the study area, establishing accurate pre-industrial baseline values is essential for a more reliable assessment. This study challenges the concept of "natural pollution" by demonstrating that human activities exacerbate baseline metal(loid)s levels. Expanding monitoring protocols is imperative to comprehensively assess the combined effects of multiple emission sources, including mining and natural processes, in safeguarding environmental and human health for future generations.
Clays tailings flocculation using bio-based flocculants from Nannochloropsis gaditana
(Springer, 2025) Huapaya, Katiuska; Grisales, Jeferson; Botero, Yesica; Salamanca, Alexandra; Lara, Paloma; Cisternas, Luis A; Jeldres, Ricardo; Jeison, David; Panico, Antonio; Zapata, Manuel; Rivas, Mariella
In copper mining water recirculation is a crucial aspect, with approximately 70% used during the ore processing stage being recirculated. After extraction, the process water has a high concentration of clays, which exert a deleterious effect on mineral concentration, so the industry employs flocculation processes to remove them using chemical flocculants derived from polyacrylamide, which are toxic and persistent in the environment. The development of bio-based flocculants derived from microalgae represents a sustainable alternative for clay removal. Therefore, sedimentation tests were performed using the Jar-test method with Nannochloropsis gaditana to remove kaolinite-type clay. The sedimented flocs were subjected to various analyses, including zeta potential, Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The zeta potential of N. gaditana is negative in deionized water across a pH ranging between 2 and 11, whereas in seawater only at pH between 7 and 9. Nannochloropsis gaditana was evaluated under different conditions (live cells, boiled cells, wet biomass, and freeze-dried biomass). Live and boiled cells were the most effective in kaolinite removal, as they instantly reduced turbidity to 76 FNU, achieving a sedimentation efficiency close to 97% at pH 7, which favored seawater clarification. Sedimentation efficiency was higher when using 10 g L−1 of live N. gaditana cells compared to the chemical flocculant used as a control. Finally, FT-IR was used to determine the degree of kaolinite absorption on the surface of microalgae, and showed that the presence of carboxylic functional groups and polysaccharide amides on the cell surface favors this interaction.
Complete genome sequence of Cellulomonas sp. strain ATA003
(American Society For Microbiology, 2024) Bartholomäus, Alexander; Mitzscherling, Julia; Lipus, Daniel; Wagner, Dirk; Lavin, Paris; Contreras, Roberto; Oses, Rómulo
The Gram-positive, rod-shaped endophytic bacterium Cellulomonas sp.strain ATA003 was isolated from the endemic cactus Maihueniopsis domeykoensis seeds collected in the Coastal Atacama Desert, Chile. Here, we present a circular genome with a size of 4,084,881 bp and a GC content of 73.8% obtained by Nanopore sequencing.
Contamination of urban soils in a historical mining town of northern Chile
(Springer Science and Business Media Deutschland GmbH, 2024) Garcia, D.; Tapia, J.; Vega, C.; Zúñiga, P.; Lavin, P.; Rojas, L.; Valdés, J.
In northern Chile, economic activities related to mining and thermoelectric energy have existed in the city of Tocopilla since the early 1900s and metal concentrations in soils have likely been altered by historic anthropogenic activities. To assess the concentrations of Cu, Zn, Pb, Ni, Co, and Cr in urban soils of Tocopilla, a total of 70 superficial (2 cm) and 70 deep (20 cm) soil samples were collected in 2014. Furthermore, to analyze concentration changes in soils over time, 18 superficial (5 cm) samples were collected in 2020–2021. A numerical evaluation (geoaccumulation index, and enrichment factor), principal component analysis, and spatial distribution approach were applied to infer geogenic and anthropogenic influence on the concentrations of these elements. The main conclusions of this research indicate that urban soils of Tocopilla contain geogenic Cu, Zn, Pb, Ni, Co and Cr. However, elevated concentrations of Cu, Zn, and Pb cannot be attributed to a geogenic origin alone, as a proportion of their enrichment is considered to be anthropogenically sourced. The contamination of anthropogenic elements has been found to be related to historic copper mining and thermoelectric energy production. Furthermore, when compared to other sites globally, median concentrations of Cu (945 mg/kg in 2014 and 823 mg/kg in 2020) and Zn (305 mg/ kg in 2014 and 196 mg/kg in 2020) in superficial urban soils are among the highest worldwide. Regarding 2020–2021 sampling, Zn and Pb concentrations have increased, while Cu, Cr, Co, and Ni have remained similar to the 2014 samples.
Critical Role of Iodine and Thyroid Hormones During Pregnancy
(MDPI, 2025) Moreno-Reyes, Rodrigo; Fuentes Pena, Camilo; Nunez, Jonathan F; Sanchez, Maria Belen; Carvajal, Jonatan J; Roble, Katherine; Mendoza-Leon, Maria Jose; Rangel-Ramirez, Ma. Andreina; Opazo, Ma. Cecilia; Lay, Margarita K; Riedel, Claudia A; Guzman-Gutierrez, Enrique; Mackern-Oberti, Juan Pablo; Jara, Evelyn L
Iodine is an essential micronutrient that is required for thyroid hormone (TH) synthesis. However, adequate maternal thyroid function is critical for fetal growth and neurodevelopment. Pregnancy increases iodine requirements due to enhanced renal clearance, higher maternal TH production, and transplacental transfer, making pregnant women especially vulnerable to iodine deficiency. In this review, we examine the molecular mechanisms of TH synthesis and regulation, placental transport and metabolism, and the physiological adaptations of thyroid function during gestation. We also analyze the clinical and public health consequences of iodine imbalances, ranging from deficiency to excess. Evidence indicates that mild iodine deficiency—which is common even in developed countries—can lead to maternal thyroid overstimulation, increased thyroglobulin levels, altered T3/T4 ratios, and enlarged thyroid volume, while severe deficiency results in maternal and fetal hypothyroidism with irreversible neurocognitive impairment in the offspring. Conversely, excessive iodine intake may impair fetal thyroid function through mechanisms such as the Wolff–Chaikoff effect. In conclusion, ensuring balanced iodine intake through iodized salt, supplementation, and routine thyroid monitoring during pregnancy is essential to protect maternal health and optimize early neurodevelopment.
Cryopreservation of yellowtail kingfish (Seriola lalandi) sperm: Effects on metabolic enzymes and sperm quality
(Elsevier, 2025) Figueroa Villalobos, Elías; Wilson, Rodolfo; Pereira, Wellison Amorim; Merino, Osvaldo; Pérez-Atehortúa, Maritza; Niedmann, Paola; Avila, Sebastián; Alvarado, Claudia; Risopatrón, Jennie; Pinheiro de Souza Oliveira, Ricardo; Farías, Jorge G; Valdebenito Isler, Iván; Villasante, Alejandro; Romero, Jaime
This study aimed to determine the effects of cryopreservation on sperm functionality and assess post-thaw sperm quality in yellowtail kingfish (Seriola lalandi). Milt designated for cryopreservation was frozen in a solution containing Cortland® medium +1.3 M Me2SO +0.2 M glucose +2 % BSA in a 1:3 ratio (milt:cryoprotectant). Fresh milt was used as the control. The samples were frozen in 0.5 mL straws using a programmable freezing system. After thawing, the samples were evaluated for motility using Computer-Assisted Sperm Analysis (CASA) with a phase-contrast optical microscope. Additionally, flow cytometry and a multimodal reader were employed to assess various sperm parameters, including plasma membrane integrity (SYBR-14/PI), mitochondrial membrane potential (ΔΨMMit: JC-1), DNA fragmentation (TUNEL), ATP content (CellTiter-Glo®), intracellular calcium levels (Fluo-4 AM), lipid peroxidation (LPO), intracellular superoxide (DHE/SYTOX) and glutathione (GSH/ GSSG) production, activities of glutathione peroxidase (GPx), catalase (CAT) and 8-oxoguanine glycosylase (OGG1), and detection of 8-hydroxydeoxyguanosine (8-OHdG). In cryopreserved milt, significant differences in motility (64.14 ±2.2 %), plasma membrane integrity (61.5 ±2.7 %), mitochondrial membrane potential (55.4 ±2.4 %), DNA fragmentation (6.7 ±1.1 %), ATP content (7.5 ±1.5 nmol/109 spermatozoa), and intracellular calcium levels (59.8 ±2.5 nM/109 spermatozoa) were observed compared to fresh milt. Differences were also noted in LPO, O2i , GPx, GSH/GSSG, CAT, 8-OHdG and OGG1 between the cryopreserved and control groups. Additionally, correlations between sperm quality parameters, oxidative stress markers, and enzyme activity in cryopreserved spermatozoa were determined. These results suggest that cryopreservation induces significant alterations derived from oxidative damage in the functionality of yellowtail kingfish spermatozoa, and thus further research is necessary to explore the need for using antioxidants in the cryopreservation process of sperm from this species.
Current Trends and Biotechnological Innovations in Biofouling Control of RO Membranes in Desalination Systems
(MDPI, 2025) Cruz-Balladares, Victoria; Vera Villalobos, Hernan; Riquelme, Carlos; Silva Aciares, Fernando
Background: Water scarcity is a pressing global challenge increasingly addressed by ad-vanced desalination that converts seawater into potable water. Reverse osmosis and ultra-filtration dominate because they deliver permeate with very low impurities. Their principallimitation is membrane biofouling, which causes clogging, raises energy, operation, andmaintenance costs, and shortens membrane life. Multiple approaches mitigate biofouling—most notably pretreatment trains and engineered surface coatings—but cleaning remainsthe most decisive remediation pathway. Current practice distinguishes physical, chemical,and biological cleaning. Biological cleaning has gained momentum by exploiting microor-ganisms that inherently counter biofilms. These strategies include targeted secretion ofenzymes and antifouling metabolites, and the application of whole-cell culture super-natants containing the full suite of secreted components. In addition, predatory bacteriacan infiltrate established biofilms and eradicate them by lysing prey, thereby acceleratingthe removal of adherent biomass. Progress across these bio-based approaches signals mean-ingful advances in fouling control and could substantially improve the efficiency, reliability,and sustainability of desalination facilities. Collectively, they underscore the transformativepotential of biological antifouling agents in operational systems. Realizing that potentialwill require rigorous evaluation of technical performance, long-term stability, compatibilitywith polyamide membranes, regulatory acceptance, and environmental safety, ultimatelyalongside scalable production and cost-effective deployment in full-scale plan
Diet of Andean Leaf-Eared Mice (Phyllotis) Living atExtreme Elevations on Atacama Volcanoes: Insights FromMetagenomics, DNA Metabarcoding, and Stable Isotopes
(WILEY, 2024) Quezada Romegialli, Claudio; Quiroga Carmona, Marcial; D'Elía, Guillermo; Harrod, Chris; Storz, Jay F.
On the flanks of > 6000 m Andean volcanoes that tower over the Atacama Desert, leaf-eared mice (Phyllotis vaccarum) live at extreme elevations that surpass known vegetation limits. The diet of these mice in these barren, hyperarid environments has been the subject of much speculation. According to the arthropod fallout hypothesis, sustenance is provided by windblown in-sects that accumulate in snowdrifts (“aolian deposits”). Mice may also feed on saxicolous lichen or forms of cryptic vegetation that have yet to be discovered at such high elevations. We tested hypotheses about the diet of mice living at extreme elevations on Atacama volcanoes by combining metagenomic and DNA metabarcoding analyses of gut contents with stable isotope analyses of mouse tissues. Genomic analyses of contents of the gastrointestinal tract of a live-captured mouse from the summit of VolcánLlullaillaco (6739 m) revealed an opportunistic but purely herbivorous diet, including lichens. Although we found no evidence of animal DNA in gut contents of the summit mouse, stable isotope data indicate that mice from elevations at or near vegetation limits (~5100 m) include a larger fraction of animal prey in their diet than mice from lower elevations. Some plant species detected in the gut contents of the summit mouse are known to exist at lower elevations at the base of the volcano and in the surrounding Altiplano, suggesting that they may occur at higher elevations beneath the snowpack or in other cryptic microhabitats.
Differences in the adulteration degree and antimicrobial activity of chilean ulmo honey versus multifloral honey revealed by stable isotope analysis
(ELSEVIER, 2024) Pérez, Pablo; Lavín, Paris; Harrod, Chris; Echeveste, Pedro
Honey, valued for its nutritional and antimicrobial benefits, has experienced an increased production in recent decades. However, this rise has been accompanied by concerns of adulteration, often involving the fraudulent addition of sugars. Our study sought to compare the physicochemical and isotopic properties of various honeys available to Chilean consumers, assessing the extent of adulteration. Samples included honey produced from bees that fed on multiple flowers and those fed by ulmo flowers – an endemic species of South America that produces a high-quality, high-cost honey – and analyzed for antimicrobial activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The analysis of ash content (%), moisture (%), pH and total phenolic content (mg GAE/100 g honey) found little obvious differences among honeys regardless of the feeding flowers (multifloral vs ulmo), type of purchase market (formal vs informal) or origin of the honeys (Central vs Southern Chile). However, the use of stable isotope analysis (δ 13 C and δ 15 N) of honey provided a powerful means to identify the degree of adulteration prior to the point of sale. Multifloral honeys purchased at informal markets were all adulterated, and ulmo honeys included both the least and most adulterated honeys. Regarding their antimicrobial activity, most multifloral honeys were less effective than ulmo honeys. Notably, while multifloral honey activity was independent of adulteration, the antimicrobial activity of ulmo honey was negatively affected by adulteration.
Different Safety Pattern of an Inactivated SARS-CoV-2 Vaccine (CoronaVac®) According to Age Group in a Pediatric Population from 3 to 17 Years Old, in an Open-Label Study in Chile
(MDPI, 2023) Le Corre, Nicole; Abarca, Katia; Astudillo, Patricio; Potin, Marcela; López, Sofía; Goldsack, Macarena; Valenzuela, Vania; Schilling, Andrea; Gaete, Victoria; Rubio, Lilian; Calvo, Mario; Twele, Loreto; González, Marcela; Fuentes, Daniela; Gutiérrez, Valentina; Reyes, Felipe; Tapia, Lorena I.; Villena, Rodolfo; Retamal Díaz, Angello; Cárdenas, Antonio; Alarcón-Bustamante, Eduardo; Meng, Xing; Xin, Qianqian; González-Aramundiz, José V.; Álvarez-Figueroa, María Javiera; González, Pablo A.; Bueno, Susan M.; Soto, Jorge A.; Perret, Cecilia; Kalergis, Alexis M.
During the COVID-19 pandemic, the importance of vaccinating children against SARS-CoV- 2 was rapidly established. This study describes the safety of CoronaVac® in children and adolescents between 3- and 17-years-old in a multicenter study in Chile with two vaccine doses in a 4-week interval. For all participants, immediate adverse events (AEs), serious AEs (SAEs), and AEs of special interest (AESIs) were registered throughout the study. In the safety subgroup, AEs were recorded 28 days after each dose. COVID-19 surveillance was performed throughout the study. A total of 1139 individuals received the first and 1102 the second dose of CoronaVac®; 835 were in the safety subgroup. The first dose showed the highest number of AEs: up to 22.2% of participants reported any local and 17.1% systemic AE. AEs were more frequent in adolescents after the first dose, were transient, and mainly mild. Pain at the inoculation site was the most frequent AE for all ages. Fever was the most frequent systemic AE for 3–5 years old and headache in 6–17 years old. No SAEs or AESIs related to vaccination occurred. Most of the COVID-19 cases were mild and managed as outpatients. CoronaVac® was safe and well tolerated in children and adolescents, with different safety patterns according to age.
Differentiation of microbial communities in coastal seawater before and during an Akashiwo sanguinea (Dinophyceae) bloom in the urban area of Antofagasta city (northern Chile)
(Elsevier, 2025) Hu, Jingming; Cameron, Henry; Rilling, Joaquín I; Campos, Marcos; Ruiz-Gil, Tay; Gonzalez, Mariela A; Gajardo, Gonzalo; Vergara, Karen; Guzmán, Leonardo; Espinoza-González, Oscar; Fuenzalida, Gonzalo; Riquelme, Carlos; Ueki, Shoko; Nagai, Satoshi; Maruyama, Fumito; Fujiyoshi, So; Yarimizu, Kyoko; Perera, Ishara Uhanie; Ávila Barrera, Andrés; Acuña, Jacquelinne J; Zhang, Qian; Jorquera, Milko A
Harmful algal blooms (HABs) are highly relevant for public health, the economy, the ecosystem, and biodiversity stability in southern Chile (40° to 53°S), where they occur regularly and are frequently monitored. However, HAB events and their associated microbes in northern Chile (17° to 30°S) remain unknown and difficult to track due to a lack of monitoring, particularly in urban areas. We investigated changes in microbial communities in coastal seawater before and during an Akashiwo sanguinea bloom (B) at two sampling points in Antofagasta city (23°38′39S, 70°24′39W). Seawater samples (filtered at 1 and 0.2 μm) were collected during distinct bloom phases (control, prebloom, and in-bloom), and 16S and 18S rDNA gene libraries were constructed and analyzed via the DNA metabarcoding technique. Our findings indicate that species diversity within the 16S rDNA-based community was greater during the prebloom phase than during the control and in-bloom phases. Conversely, species diversity within the 18S rDNA-based community was lower during the in-bloom phase than during the control and prebloom phases. Independent of the sampling points and fractions, principal coordinate analysis (PCoA) revealed distinct differences in both the 16S and 18S rDNA-based communities between the analyzed bloom phases. Our analysis further revealed that the 16S rDNA-based community was dominated by the Flavobacteriaceae and Rhodobacteraceae families, whose abundance decreased and increased, respectively, during the bloom. As anticipated, the structure of the 18S rDNA-based community was predominantly governed by the Gymnodiniaceae family, specifically the Akashiwo genus, during the bloom. The differentiation in microbial communities was more pronounced in taxa with low abundances than in the dominant taxa. Additionally, co-occurrence network analysis revealed predominantly positive relationships within the microbial communities, particularly during the bloom event. Our analysis also identified several bacterial genera as keystone taxa within the microbial communities, notably members of Pseudomonadota and Bacteroidota. © 2024 Elsevier B.V.
Energetic convergence drives metabolic adaptation in lirima chilean high-altitude hydrothermal system
(Springer Nature, 2025) Paquis, Pablo; Pardo Esté, Coral; Tapia, Joseline; Florez, July Z; Pérez, Vilma; Molina, Verónica; Cornejo-D'Ottone, Marcela; Pérez, Pablo A; Harrod, Chris; Jeffrey, Wade H; Calabrese, Sergio; Quatrini, Paola; Tassi, Franco; Hengst, Martha B
High-altitude hydrothermal systems provide laboratories for understanding microbial adaptation to extreme conditions. Here we investigated thermodynamic controls on metabolic transitions in Lirima hydrothermal system (Chile, 4000 meters above sea level) calculating affinities of competing carbon and sulfur reactions across pools (53-75 degrees C). Through geochemistry, numerical thermodynamic modeling, and stable isotope analysis, we identify Energetic Convergence Nodes where chemical affinities of competing pathways become equal. Calculations reveal hydrogenotrophic and carboxydotrophic methanogenesis converge with sulfate reduction at 63-64 degrees C. This corresponds with responses: carbon isotopes shift from -17.2 parts per thousand to -27.7 parts per thousand, sulfur isotopes from -20.5 parts per thousand to -9.1 parts per thousand, and carbon-to-sulfur ratios drop from similar to 10 to <1, indicating transition from carbon to sulfur-dominated metabolism. Microbial activity collapses at this temperature, while metagenomics validates both pathways. Independent analysis confirms convergence at 63-64 degrees C, establishing Energetic Convergence Nodes as predictive frameworks for metabolic boundaries with applications for early Earth biogeochemistry and extraterrestrial biosignature detection.
Environmental Stability Drives and Maintains the Global Patterns of Phylogenetic Endemism in the Marine Realm
(Wiley, 2025) Rivera, Reinaldo; Gonzalez, Carolina E; Hidalgo, Pamela; Urbina, Mauricio A; Escribano, Ruben
Aim: Endemism is a critical aspect of biological diversity, yet the mechanisms driving it remain unclear. The leading hypoth-esis posits that prolonged environmental stability fosters speciation and reduces extinction rates, promoting endemism. Whileterrestrial studies exist, marine environments remain underexplored. This study analysed the global distribution and drivers ofphylogenetic endemism in two marine taxa: Calanidae copepods and Blenniidae fish.Location: Global.Time Period: From the Last Glacial Maximum (LGM, past 24,000 years) to the current period.Taxa: Calanidae copepods and Blenniidae fish.Methods: We assessed taxonomic and phylogenetic diversity, endemism and areas of paleo- and neo-endemism usingCategorical Analysis of Neo- and Paleo-Endemism and Piecewise Structural Equation Modelling to evaluate the influence ofpresent-day and historical environmental variables.Results: Results showed consistent diversity patterns and significant endemism hotspots, with Calanidae in the SouthernHemisphere and Blenniidae in the Northern Hemisphere. Tropical regions, particularly the Indonesian-Australian Archipelago(IAA), exhibited high species richness and endemism for both groups. Paleo- endemism was observed in the Pacific for Calanidaeand the IAA for Blenniidae, suggesting that these areas are either relict diversity centres or diversification hubs.Main Conclusions: The Mediterranean and Caribbean Seas emerged as biodiversity cradles for Calanidae and Blenniidae re-spectively. Phylogenetic endemism is driven by both historical and contemporary factors, with centres of endemism emergingin regions where past environmental fluctuations have been moderate (hypothesis 1) and where cold, productive ocean currentsfoster the development of endemic areas (hypothesis 2). These findings underscore the importance of historical stability in oceantemperatures in shaping phylogenetic endemism, indicating that long-term environmental stability sustains marine endemism
Epibiotic bacterial community composition varies during different developmental stages of Octopus mimus: Study of cultivable representatives and their secondary metabolite production
(Public Library of Science, 2024) Hengst, Martha B.; Trench, Stephanie; Alcayaga, Valezka; Sepulveda Muñoz, Cristian; Bórquez, Jorge; Simirgiotis, Mario; Valenzuela, Fernando; Lody, Mario; Kurte, Lenka; Pardo Esté, Coral
Marine microbial communities colonizing the skin of invertebrates constitute the primary barrier between host and environment, potentially exerting beneficial, neutral, or detrimental effects on host fitness. To evaluate the potential contribution of epibiotic bacteria to the survival of early developmental stages of Octopus mimus, bacterial isolates were obtained from eggs, paralarvae, and adults. Their enzymatic activities were determined, and antibacterial properties were assessed against common marine pathogens. The isolates belonged to the phyla Proteobacteria, Actinomycetota, Bacteroidota, and Bacillota, represented by 21 genera and 27 species. Specific taxa were associated with each developmental stage, with only three species shared among different stages: Bacillus pumilus, B. megaterium, and Shewanella algae, which also inhibited the growth of all assayed pathogens. Organic extracts from Bacillus megaterium M8-1 were obtained, and UHPLC-MS analysis detected seventeen putative compounds, including two phenolic acids, three indole derivatives, and twelve oxylipins. Our findings provide novel data on cultivable bacterial representatives isolated from Octopus mimus capable of synthesizing chemical compounds with bioactive properties. These results contribute to a better understanding of the role of microbial communities in the survival of this invertebrate species during critical early life stages.

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