Facultad de Ciencias del Mar y Recursos Biológicos

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Response to static magnetic field-induced stress in scenedesmus obliquus and nannochloropsis gaditana
(2021) Génesis Serrano; Carol Miranda-Ostoijc; Pablo Ferrada; Cristian Wulff-Zotelle; Alejandro Maureira; Edward Fuentealba; Karem Gallardo; Manuel Zapata; Mariella Rivas
Magnetic fields in biological systems is a promising research field; however, their application for microalgae has not been fully exploited. This work aims to measure the enzymatic activity and non-enzymatic activity of two microalgae species in terms of superoxide dismutase (SOD), catalase (CAT), and carotenoids, respectively, in response to static magnetic fields-induced stress. Two magnet configurations (north and south) and two exposure modes (continuous and pulse) were applied. Two microalgae species were considered, the Scenedesmus obliquus and Nannochloropsis gaditana. The SOD activity increased by up to 60% in S. obliquus under continuous exposure. This trend was also found for CAT in the continuous mode. Conversely, under the pulse mode, its response was hampered as the SOD and CAT were reduced. For N. gaditana, SOD increased by up to 62% with the south configuration under continuous exposure. In terms of CAT, there was a higher activity of up to 19%. Under the pulsed exposure, SOD activity was up to 115%. The CAT in this microalga was increased by up to 29%. For N. gaditana, a significant increase of over 40% in violaxanthin production was obtained compared to the control, when the microalgae were exposed to SMF as a pulse. Depending on the exposure mode and species, this methodology can be used to produce oxidative stress and obtain an inhibitory or enhanced response in addition to the significant increase in the production of antioxidant pigments.
Inactivated Vaccine-Induced SARS-CoV-2 Variant-SpeciﬁcImmunity in Children
(2022) Jorge A. Soto; Felipe Melo González; Cristián Gutierrez Vera; Bárbara M. Schultz; Roslye V. Berríos Rojas; Daniela Rivera Pérez; Alejandro Piña Iturbe; Guillermo Hoppe Elsholz; Luisa F. Duarte; Yaneisi Vázquez; Daniela Moreno Tapia; Mariana Ríos; Pablo A. Palacios; Richard Garcia Betancourt; Álvaro Santibañez; Gaspar A. Pacheco; Constanza Mendez; Catalina A. Andrade; Pedro H. Silva; Benjamín Diethelm Varela; Patricia Astudillo; Mario Calvo; Antonio Cárdenas; Marcela González; Macarena Goldsack; Valentina Gutiérrez; Marcela Potin; Andrea Schilling; Lorena I. Tapia; Loreto Twele; Rodolfo Villena; Alba Grifoni; Alessandro Sette; Daniela Weiskopf; Rodrigo A. Fasce; Jorge Fernández; Judith Mora; Eugenio Ramírez; Aracelly Gaete Argel; Mónica L. Acevedo; Fernando Valiente Echeverría; Ricardo Soto Rifo; Angello Retamal Díaz; Nathalia Muñoz Jofré; PedCoronaVac03CL Study Group; Xing Meng; Qianqian Xin; Eduardo Alarcón Bustamante; José V. González Aramundiz; Nicole Le Corre; María Javiera Álvarez Figueroa; Pablo A. González; Katia Abarca; Cecilia Perret; Leandro J. Carreño; Susan M. Bueno; Alexis M. Kalergis
Multiple vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been evaluated in clinical trials. However, trials addressing the immune response in the pediatric population are scarce. The inactivated vaccine CoronaVac has been shown to be safe and immunogenic in a phase 1/2 clinical trial in a pediatric cohort in China. Here, we report interim safety and immunogenicity results of a phase 3 clinical trial for CoronaVac in healthy children and adolescents in Chile. Participants 3 to 17 years old received two doses of CoronaVac in a 4-week interval until 31 December 2021. Local and systemic adverse reactions were registered for volunteers who received one or two doses of CoronaVac. Whole-blood samples were collected from a subgroup of 148 participants for humoral and cellular immunity analyses. The main adverse reaction reported after the first and second doses was pain at the injection site. Four weeks after the second dose, an increase in neutralizing antibody titer was observed in subjects relative to their baseline visit. Similar results were found for activation of specific CD41 T cells. Neutralizing antibodies were identified against the Delta and Omicron variants. However, these titers were lower than those for the D614G strain. Importantly, comparable CD41 T cell responses were detected against these variants of concern. Therefore, CoronaVac is safe and immunogenic in subjects 3 to 17 years old, inducing neutralizing antibody secretion and activating CD41 T cells against SARS-CoV-2 and its variants. (This study has been registered at ClinicalTrials .gov under no. NCT04992260.)
Sulfate Nutrition Modulates the Oxidative Response against Short-Term Al3+-Toxicity Stress in Lolium perenne cv. Jumbo Shoot Tissues
(2024) Hernan Vera Villalobos; Lizzeth Lunario Delgado; Anita S. Gálvez; Domingo Román Silva; Ana Mercado Seguel; Cristián Wulff Zottele
Al3+-toxicity in acidic soils is among the main abiotic stress factors that generate adverse effects in plant growth; in leaves, it affects several physiological parameters such as photosynthesis and ROS balance, leading to limited crop production. On the other hand, sulfur is a macronutrient that has a key role against oxidative stress and improves plant growth in acidic soils; however, the implication of sulfate nutritional status in the modulation of short-term Al3+-toxicity tolerance mechanisms in plant leaves are barely reported. This study is focused on the role of sulfate on the leaf response of an Al3-sensitive perennial ryegrass (Lolium perenne cv. Jumbo) after 48 h of exposure. Lolium perenne cv. Jumbo seeds were cultivated in hydroponic conditions with modified Taylor Foy solutions supplemented with 120, 240, and 360 μM sulfate in the presence or absence of Al3+-toxicity. The L. perenne cv. Jumbo leaves were collected after 48 h of Al3+-toxicity exposure and processed to evaluate the effects of sulfate on Al3+ toxicity, measuring total proteins, mineral uptake, photosynthesis modulation, and ROS defense mechanism activation. The plants exposed to Al3+-toxicity and cultivated with a 240 μM sulfate amendment showed a recovery of total proteins and Ca2+ and Mg2+ concentration levels and a reduction in TBARS, along with no changes in the chlorophyll A/B ratio, gene expression of proteins related to photosynthesis (Rubisco, ChlAbp, and Fered), or ROS defense mechanism (SOD, APX, GR, and CAT) as compared with their respective controls and the other sulfate conditions (120 and 360 μM). The present study demonstrates that adequate sulfate amendments have a key role in regulating the physiological response against the stress caused by Al3+ toxicity.
Isolation of Thermophilic Bacteria from Extreme Environments in Northern Chile
(2024) Bernardita Valenzuela; Francisco Solís Cornejo; Rubén Araya; Pedro Zamorano
The northern region of Chile boasts unique geographical features that support the emergence of geothermal effluents, salt lagoons, and coastal creeks. These extreme climate conditions create polyextreme habitats for microorganisms, particularly adapted to survive these harsh environments. These extremophilic microorganisms hold immense potential as a source of hydrolytic enzymes, among other biotechnological applications. In this study, we isolated 15 strains of aerobic thermophilic bacteria (45–70 ◦C) from sediment samples collected at five different ecological sites, including hot springs, geothermal fields, and lagoons in the Atacama Desert and Andes high planes. Analyses of the 16S rRNA gene sequences of the isolates showed a close genetic similarity (98–100%) with microorganisms of the genera Parageobacillus, Geobacillus, Anoxybacillus, and Aeribacillus. Notably, these thermophiles exhibited significant hydrolytic enzyme activity, particularly amylases, lipases, and proteases. These findings underscore the potential of using these thermophilic bacterial strains as an invaluable source of thermozymes with wide-ranging applications in diverse industries, such as detergent formulations, pharmaceutical processing, and food technology. This research highlights the ecological significance of these extreme environments in the Atacama Desert and Andes high plains, which serve as vital ecological niches housing extremophilic bacteria as a genetic source of relevant thermozymes, promising great potential for innovation in the biotechnology industry.
The Chilean COVID-19 Genomics Network Biorepository: A Resource for Multi-Omics Studies of COVID-19 and Long COVID in a Latin American Population
(2024) Iskra A. Signore; Gerardo Donoso; Pamela Bocchieri; Eduardo A. Tobar-Calfucoy; Cristian E. Yáñez; Laura Carvajal-Silva; Andrea X. Silva; Carola Otth; Claudio Cappelli; Héctor Valenzuela Jorquera; Daniela Zapata Contreras; Yolanda Espinosa Parrilla; Paula Zúñiga Pacheco; Macarena Fuentes Guajardo; Virginia A. Monardes Ramírez; Pia Kochifas Velasquez; Christian A. Muñoz; Cristina Dorador; Jonathan García Araya; Claudia P. Campillay Véliz; Cesar Echeverria; Rodolfo Alejandro Santander; Leslie C. Cerpa; Matías F. Martínez; Luis Abel Quiñones; Eduardo Roberto Lamoza Galleguillos; Juan Saez Hidalgo; Estefanía Nova-Lamperti; Sergio Sanhueza; Annesi Giacaman; Gerardo Acosta Jamett; Cristóbal Verdugo; Anita Plaza; Claudio Verdugo; Carolina Selman; Ricardo Alejandro Verdugo; Alicia Colombo
Although a lack of diversity in genetic studies is an acknowledged obstacle for personalized medicine and precision public health, Latin American populations remain particularly understudied despite their heterogeneity and mixed ancestry. This gap extends to COVID-19 despite its variability in susceptibility and clinical course, where ethnic background appears to influence disease severity, with non-Europeans facing higher hospitalization rates. In addition, access to high-quality samples and data is a critical issue for personalized and precision medicine, and it has become clear that the solution lies in biobanks. The creation of the Chilean COVID-19 Biorepository reported here addresses these gaps, representing the first nationwide multicentric Chilean initiative. It operates under rigorous biobanking standards and serves as one of South America’s largest COVID cohorts. A centralized harmonization strategy was chosen and included unified standard operating procedures, a sampling coding system, and biobanking staff training. Adults with confirmed SARS-CoV-2 infection provided broad informed consent. Samples were collected to preserve blood, plasma, buffy coat, and DNA. Quality controls included adherence to the standard preanalytical code, incident reporting, and DNA concentration and absorbance ratio 260/280 assessments. Detailed sociodemographic, health, medication, and preexisting condition data were gathered. In five months, 2262 participants were enrolled, pseudonymized, and sorted by disease severity. The average Amerindian ancestry considering all participant was 44.0% [SD 15.5%], and this value increased to 61.2% [SD 19.5%] among those who self-identified as Native South Americans. Notably, 279 participants self-identified with one of 12 ethnic groups. High compliance (>90%) in all assessed quality controls was achieved. Looking ahead, our team founded the COVID-19 Genomics Network (C19-GenoNet) focused on identifying genetic factors influencing SARS-CoV-2 outcomes. In conclusion, this bottom-up collaborative effort aims to promote the integration of Latin American populations into global genetic research and welcomes collaborations supporting this endeavor. Interested parties are invited to explore collaboration opportunities through our catalog, accessible online.
Rapid detection of enterobacteria inwastewater treated by microalgal consortiausing loop-mediated isothermalamplification (LAMP)
(2024) Henry Cameron; Jazmín Bazaes; Claudia Sepúlveda; Carlos Riquelme
In the present study, nine Enterobacteriaceae species present in wastewater were isolated and identified, and loop-mediated isothermal amplification (LAMP) was developed for the detection of Enterobacteriaceae by designing primers based on themcr-1, KPC, OXA-23, and VIM genes, which are recognized markers of antimicrobial resistance (AMR) transmission during microalgal bioremediation treatment. The developed assays successfully detected four strains positive for mcr-1gene-asociated resistance (Acinetobacter baylyi,Klebsiella pneumoniae,Morganellamorganii, andSerratia liquefaciens), three strains for KPC gene-associated resistance(Acinetobacter sp.,Escherichia coli15499, and Morganella morganii), seven strains for OXA-23 gene-associated resistance (Acinetobacter baylyi,Enterobacterhormaechi,Enterobacter cloacae,Escherichia coli15922,Escherichia coli51446,Morganella morganii, and Serratia liquefaciens), and three strains for resistance to the VIM gene-associated resistance (Acinetobacter baylyi,Acinetobactersp., and Enterobacter hormaechi) from a single colony. A reduction in microbiological load of93.6% was achieved at 15 colony-forming units (CFU) mL-1, utilizing EMB agar andLAMP values of 0.142 ± 0.011 for the mcr-1 gene, 0.212 ± 0.02 for the KPC gene,0.233 ± 0.006 for the OXA-23 gene, and 0.219 ± 0.035 for the VIM gene.Furthermore, bioremediation efficiency values of 71.6% and 75% for total nitrogen and phosphorus, respectively, were observed at 72 h of treatment in open pond microalgal remediation systems (MRS). This study demonstrated that the LAMP technique is faster and more sensitive than traditional detection methods, such as CFU, for Enterobacteriaceae. Consequently, this method may be considered for the detection of microbiological quality indicators within the water treatment industry
Complete genome sequence of Cellulomonas sp. strain ATA003
(2024) Alexander Bartholomäus; Julia Mitzscherling; Daniel Lipus; Dirk Wagner; Paris Lavin; Roberto Contreras; Rómulo Oses
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.
Nitrification characteristics and microbial community changes during conversion of freshwater to seawater in down-flow hanging sponge reactor
(2024) Takumi Akamine; Mami Nagai; Takahiro Watari; Hirotoshi Netsu; Nur Adlin; Penpicha Satanwat; Carlos Riquelme; Masashi Hatamoto; Takashi Yamaguchi
In recirculating aquaculture systems (RAS), maintaining water quality in aquaculture tanks is a paramount factor for effective fish production. A down-flow hanging sponge (DHS) reactor, a trickling filter system used for water treatment of RAS that employs sponges to retain biomass, has high nitrification activity. However, nitrification in seawater RAS requires a long start-up time owing to the high salinity stress. Therefore, this study aimed to evaluate the nitrification characteristics and changes in the microbial community during the conversion of freshwater to seawater in a DHSreactor fed with ammonia-based artificial seawater. The total ammonia nitrogen concentration reached 1.0 mg-N⋅L 1 (initial concentration 10 mg-N⋅L 1) within 11 days of operation, and nitrate production was observed. The 16 S rRNA gene sequence of the DHS-retained sludge indicated that the detection rate of the ammonia-oxidizing archaeon Candidatus Nitrosocosmicus decreased from 23.9 % to 14.0 % and 25.8–17.6 % in the upper and lower parts of the DHS reactor, respectively, after the introduction of seawater. In contrast, the nitrite-oxidizing bacteria Nitrospira spp. increased from 0.1 % to 9.5 % and from 0.5 % to 10.5 %, respectively. The ammonia oxidation rates of 0.12 ±0.064 and 0.051 ±0.0043 mg-N⋅g-MLVSS 1⋅h 1 on the 37th day in the upper and bottom layers, respectively. Thus, nitrification in the DHS reactor performed well, even under high-salinity conditions with short operational days. This finding makes the transition from freshwater to saltwater fish in the RAS system simple and economical, and has the potential for early start-up of the RAS.
Secondary metabolites with antimicrobial activity produced by thermophilic bacteria from a high-altitude hydrothermal system
(2024) Coral Pardo Esté; Johanna Cortés; Juan Castro Severyn; Vilma Pérez; Karem Henriquez Aedo; Fabian Cuadros; Carolina Yañez; Sara Cuadros Orellana; Cristina Dorador; Veronica Molina; Yoanna Eissler; Pablo Paquis; Wade H. Jeffrey; Patricia Pozo; Pablo A. Pérez; Martha B. Hengst
Thermophilic microorganisms possess several adaptations to thrive in high temperature, which is reflected as biosynthesis of proteins and thermostable molecules, isolation and culture represent a great methodological challenge, therefore High throughput sequencing enables screening of the whole bacterial genome for functional potential, providing rapid and cost-effective information to guide targeted cultures for the identification and characterization of novel natural products. In this study, we isolated two thermophilic bacterial strains corresponding to Bacillus LB7 and Streptomyces LB8, from the microbial mats in the Atacama Desert. By combining genome mining, targeted cultures and biochemical characterization, we aimed to identify their capacity to synthesize bioactive compounds with antimicrobial properties. Additionally, we determined the capability to produce bioactive compounds under controlled in vitro assays and detected by determining their masses by Thin-Layer Chromatography/Mass Spectrometry (TLC/MS). Overall, both isolates can produce antimicrobial (e.g., Myxalamide C by-product) and antioxidants (e.g. Dihydroxymandelic Acid, Amide biotine and Flavone by-products) compounds. Bacillus LB7 strain possesses a more diverse repertoire with 51.95% of total metabolites unmatched, while Streptomyces LB8 favors mainly antioxidants, but has over 70% of unclassified compounds, highlighting the necessity to study and elucidate the structure of novel compounds. Based on these results, we postulate that the uncultured or rare cultured thermophiles inhabiting high-altitude hydrothermal ecosystems in the Atacama Desert offer a promising opportunity to the study of novel microbial bioactive compounds.
First screening of bacteria assemblages associated with the marine polychaete Melinna palmata Grube, 1870 and adjacent sediments
(2024) Selma Menabit; Paris Lavin; Tatiana Begun; Mihaela Muresan; Adrian Teaca; Cristina Purcarea
Bacteria associated with marine invertebrate play a fundamental role in the biology, ecology, development and evolution of their hosts. Although many studies have been focused on the microbial populations of benthic and pelagic habitats, little is known about bacteria colonizing tube-dwelling polychaete. In this context, the current study provided the first characterization of the Melinna palmata Grube, 1870 microbiome based on Illumina sequencing of 16S rRNA gene of the polychaete tissue and proximate sediments collected from the Black Sea, Romania, along a 24.2 m - 45.4 m depth-gradient. The diversity, taxonomic composition and deduced functional profile of the tissue and sediments associated bacterial communities were compared and analyzed in relation with the environmental parameters. This polychaete harbored a distinct bacterial assemblage as compared to their sediments and independent on the depth of their habitat, including 8 phyla in tissues dominated by Proteobacteria, and 12 phyla in sediments majorly represented by Actinobacteriota, respectively. At order level, Synechococcales, Rhodobacterales and Actinomarinales were highly represented in the M. palmata microbiome, while Microtrichales, Anaerolineales and Caldilineales were mostly found in sediments. A significant correlation was observed between Cyanobacteria taxa and the dissolved oxygen concentrations in shallow waters impacted by the Danube inputs. Meanwhile, this phylum showed a positive correlation with Planctomycetota colonizing the invertebrate tissues, and a negative one with Actinobacteriota and Chloroflexi found in sediments. The deduced functional profile of these bacterial assemblages suggested the prevalence of the amino acid and carbohydrate metabolism for both analyzed matrices. This pioneering report on the M. palmata microbiome highlighted the environment contribution to bacterial species enrichment of the polychaete, and provided a glimpse on the putative role of microbial communities associated with this marine organism.
Whole-genome sequencing of a Janthinobacterium sp. isolatedfrom the Patagonian Desert
(2024) Nicole T. Cavanaugh; Girish Kumar; Alicyn Reverdy Pearson; Julia Colbert; Carlos Riquelme; André O. Hudson; Yunrong Chai; Veronica Godoy Carter
Janthinobacterium is a genus of Gram-negative environmental bacteria that survive extreme conditions by forming biofilms and producing pigments. Janthinobacterium sp. LS2A, an extremophile isolated from soil in the Chilean Patagonia, contains seven known biosynthetic gene clusters, including the purple pigment violacein, which may aid in its survival in harsh environments.
Shared governance in the plant holobiont and implications for one health
(2024) Gabriele Berg; Cristina Dorador; Dilfuza Egamberdieva; Joel E. Kostka; Choong-Min Ryu; Birgit Wassermann
The holobiont Holobiont theory is more than 80 years old, while the importance of microbial communities for plant holobionts was already identified by Lorenz Hiltner more than a century ago. Both concepts are strongly supported by results from the new field of micr obiome r esear c h. Here , w e present ecolog ical and g enetic featur es of the plant holobiont that underpin principles of a shar ed governance between hosts and microbes and summarize the relevance of plant holobionts in the context of global c hange . Moreover, we unco ver kno wledge gaps that arise when inte gr ating plant holobionts in the broader perspective of the holobiome as well as one and planetary health concepts. Action is needed to consider interacting holobionts at the holobiome scale, for prediction and control of microbiome function to improve human and environmental health outcomes.
Protist communities of microbial mats from the extreme environments of five saline Andean lagoons at high altitudes in the Atacama Desert
(2024) Eduardo Acosta; Frank Nitsche; Cristina Dorador; Hartmut Arndt
Introduction:Heterotrophic protists colonizing microbial mats have received little attention over the last few years, despite their importance in microbial food webs. A significant challenge originates from the fact that many protists remain uncultivable and their functions remain poorly understood.Methods:Metabarcoding studies of protists in microbial mats across high-altitude lagoons of different salinities (4.3–34 practical salinity units) were carried out to provide insights into their vertical stratification at the millimeter scale. DNA and cDNA were analyzed for selected stations.Results:Sequence variants classified as the amoeboid rhizarian Rhogostoma and the ciliate Euplotes were found to be common members of the heterotrophic protist communities. They were accompanied by diatoms and kinetoplastids.Correlation analyses point to the salinity of the water columnas a main driver influencing the structure of the protist communities at the five studied microbial mats. The active part of the protist communities was detected to be higher at lower salinities (<20 practical salinity units).Discussion:We found a restricted overlap of the protist community between the different microbial mats indicating the uniqueness of these different aquatic habitats. On the other hand, the dominating genotypes present in metabarcoding were similar and could be isolated and sequenced in comparative studies(Rhogostoma, Euplotes,Neobodo). Our results provide a snapshot of the unculturable protist diversity thriving the benthic zone of ive athalossohaline lagoons across the Andean plateau.
Insights into the diversity and survival strategies of soil bacterial isolates from the Atacama Desert
(2024) Alicyn Reverdy; Daniel Hathaway; Jessica Jha; Gabriel Michaels; Jeffrey Sullivan; Daniela Diaz McAdoo; Carlos Riquelme; Yunrong Chai; Veronica Godoy Carter
The Atacama Desert, the driest, with the highest radiation, and one of the most ancient deserts in the world, is a hostile environment for life. We have a collection of 74 unique bacterial isolates after cultivation and confirmation by 16S rRNA gene sequencing. Pigmentation, biofilm formation, antimicrobial production against Escherichia coli MG1655 and Staphylococcus aureus HG003,and antibiotic resistance were assessed on these isolates. We found that approximately a third of the colonies produced pigments, 80% of isolates formed biofilms, many isolates produce growth inhibiting activities against E. coliand/orS. aureus, and many were resistant to antibiotics. The functional characterization of these isolates gives us insight into the adaptive bacterial strategies in harsh environments and enables us to learn about their possible use in agriculture,healthcare, or biotechnology.
Differences in the adulteration degree and antimicrobial activity of chilean ulmo honey versus multifloral honey revealed by stable isotope analysis
(2024) Pablo Pérez; Paris Lavín; Chris Harrod; Pedro Echeveste
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.
Rapid detection of enterobacteria in wastewater treated by microalgal consortia using loop-mediated isothermal amplification (LAMP)
(2024) Henry Cameron; Jazmín Bazaes; Claudia Sepúlveda; Carlos Riquelme
In the present study, nine Enterobacteriaceae species present in wastewater were isolated and identified, and loop-mediated isothermal amplification (LAMP) was developed for the detection of Enterobacteriaceae by designing primers based on the mcr-1, KPC, OXA-23, and VIM genes, which are recognized markers of antimicrobial resistance (AMR) transmission during microalgal bioremediation treatment. The developed assays successfully detected four strains positive for mcr-1 gene-asociated resistance (Acinetobacter baylyi, Klebsiella pneumoniae, Morganella morganii, and Serratia liquefaciens), three strains for KPC gene-associated resistance (Acinetobacter sp., Escherichia coli 15499, and Morganella morganii), seven strains for OXA-23 gene-associated resistance (Acinetobacter baylyi, Enterobacter hormaechi, Enterobacter cloacae, Escherichia coli 15922, Escherichia coli 51446, Morganella morganii, and Serratia liquefaciens), and three strains for resistance to the VIM gene-associated resistance (Acinetobacter baylyi, Acinetobacter sp., and Enterobacter hormaechi) from a single colony. A reduction in microbiological load of 93.6% was achieved at 15 colony-forming units (CFU) mL-1, utilizing EMB agar and LAMP values of 0.142 +/- 0.011 for the mcr-1 gene, 0.212 +/- 0.02 for the KPC gene, 0.233 +/- 0.006 for the OXA-23 gene, and 0.219 +/- 0.035 for the VIM gene. Furthermore, bioremediation efficiency values of 71.6% and 75% for total nitrogen and phosphorus, respectively, were observed at 72 h of treatment in open pond microalgal remediation systems (MRS). This study demonstrated that the LAMP technique is faster and more sensitive than traditional detection methods, such as CFU, for Enterobacteriaceae. Consequently, this method may be considered for the detection of microbiological quality indicators within the water treatment industry.
From a Brown to a blue economy in Chile
(2024) Jeremy Anbleyth-Evans; Francisco Araos Leiva; Carlos F. Gaymer; Ricardo R. Alvarez Abel; Leonardo Campos; Carlos Hidalgo
Marine, Economy, Democracy, Ecology, Transitions
Why aquatic scientists should use sulfur stable isotope ratios (ẟ34S) more often
(2024) Vincent Raoult; Alexandra A. Phillips; James Nelson; Yuri Niella; Christina Skinner; Miranda Bell Tilcock; Patrick J. Burke; Paul Szpak; W. Ryan James; Chris Harrod
Over the last few decades, measurements of light stable isotope ratios have been increasingly used to answer questions across physiology, biology, ecology, and archaeology. The vast majority analyse carbon (δ13C) and nitrogen (δ15N) stable isotopes as the ‘default’ isotopes, omitting sulfur (δ34S) due to time, cost, or perceived lack of benefits and instrumentation capabilities. Using just carbon and nitrogen isotopic ratios can produce results that are inconclusive, uncertain, or in the worst cases, even misleading, especially for scientists that are new to the use and interpretation of stable isotope data. Using sulfur isotope values more regularly has the potential to mitigate these issues, especially given recent advancements that have lowered measurement barriers. Here we provide a review documenting case studies with real-world data, re-analysing different biological topics (i.e. niche, physiology, diet, movement and bioarchaeology) with and without sulfur isotopes to highlight the various strengths of this stable isotope for various applications. We also include a preliminary meta-analysis of the trophic discrimination factor (TDF) for sulfur isotopes, which suggest small (mean 0.4 ± 1.7 ‰ SD) but taxa- dependent mean trophic discrimination. Each case study demonstrates how the exclusion of sulfur comes at the detriment of the results, often leading to very different outputs, or missing valuable discoveries entirely. Given that studies relying on carbon and nitrogen stable isotopes currently underpin most of our understanding of various ecological processes, this has concerning implications. Collectively, these examples strongly suggest that researchers planning to use carbon and nitrogen stable isotopes for their research should incorporate sulfur where possible, and that the new ‘default’ isotope systems for aquatic science should now be carbon, nitrogen, and sulfur.
Diet of Andean Leaf-Eared Mice (Phyllotis) Living atExtreme Elevations on Atacama Volcanoes: Insights FromMetagenomics, DNA Metabarcoding, and Stable Isotopes
(2024) Claudio Quezada Romegialli; Marcial Quiroga Carmona; Guillermo D'Elía; Chris Harrod; Jay F. Storz
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.
Metals and metaloid preserved in marine sediments of an industrial complex of central Chile. Environmental assessment using different background values
(2024) Jorge Valdés Saavedra; Eduardo Quiroga
This work examines the distribution of metals(oid) in coastal sediments of the Concon-Quintero industrial complexes (central Chile), and evaluates the environmental condition of this zone, using some environmental indexes and different global and local background values. The Index of geoaccumulation and the Enrichment Factor were different depending on the background values used to calculate them. Only Mo and Pb, simultaneously show both an enrichment, and some degree of pollution problem, with all backgrounds utilized. Three of the four background values used in this work to calculates the Pollution Load Index suggests a polluted condition of the bottom environment. The spatial distribution, the results of environmental indices and the comparison with local environmental legislation suggests that Pb is introduced to the marine system by industrial activities. The result of both, SQG and m-ERM-Q suggest that metals preserved in the sediments are a threat to the benthic life, especially in the Concon-Ritoque zone, where the highest values were recorded. These results suggest a notorious influence of the Aconcagua river on the metal accumulation in the coastal zone.

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