Departamento de Biotecnología

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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.
High nutrient requirement on the photosynthetic performance of a diatom species of the genus Nitzschia (Bacillariophyta) isolated from the high-altitude wetland, Salar de Huasco, Chile
(Wiley, 2025) Eissler, Yoanna; Anabalon, Jeremy; Celis-Pla, Paula S. M; Kieft, Brandon; Junier, Pilar; Rivera, Patricio; Cruces, Fabiola; Ascencio, Enrique; Dorador, Cristina; Molina, Veronica
This study characterizes the ecophysiological responses andgrowth dynamics of Nitzschia palea isolated from Salar deHuasco, Chile, a high-altitude wetland located at 3800 mabove sea level. The culture was maintained at 17_x000E_C undercool-white ﬂuorescent light with a 14:10 h light/dark photo-cycle and a photon ﬂux of 50 μmol photons m_x0003_2 s_x0003_1 . The dia-tom was identiﬁed morphologically and genetically, withphylogenetic analysis conﬁrming its close relationship toknown N. palea strains. Photophysiological responses weremeasured along with a series of media and temperature condi-tions in N. palea strain. Modiﬁed f/2 media supplementedwith different concentrations of Si, Se and vitamins weretested. Subsequently, growth in the double-Si f/2 media wasassessed at three different temperatures. Lastly, the diatomstrain was incubated at 17_x000E_C and 27–29_x000E_C in f/2 + double-Si(NN: non-extra nutrient addition) and a highly eutrophic stateof f/2 (WN: with nutrient enrichment addition). The highestgrowth was observed using the f/2 media WN at 17_x000E_C (day5, 4.46 _x0004_ 105 _x0005_ 3.15 _x0004_ 104 SD cells mL_x0003_1 ). Temperaturesigniﬁcantly inﬂuenced growth; 17_x000E_C supported higher celldensities and more stable photosynthetic parameters com-pared 27–29_x000E_C. Nutrient enrichment further enhanced photo-synthetic efﬁciency (αETR) and maximal quantum yield(Fv/F m), particularly under control temperature conditions.Photosynthetic performance, assessed via rapid light-responsecurves, showed signiﬁcant temperature and nutrient depen-dent variation. Nitzschia palea cultures at 27–29_x000E_C exhibitedincreased in relative maximal ETR (rETR max ,184.1μmol m_x0003_2 s_x0003_1 ) compared to control conditions. In nutrientenriched treatments, photosynthetic efﬁciency peaked on day5, but declined by day 8. These ﬁndings highlight theadaptive capacity of N. palea to ﬂuctuating environmentalconditions and underscore its potential as a model organismfor studying diatom responses to nutrient and temperaturestress in extreme ecosystems
Identifying knowledge gaps in hypersaline systems supporting the global electrical transition: invertebrate community structure in salars from the lithium triangle
(PeerJ Inc., 2025) Salazar, Gonzalo; Aguilar, Pablo; Harrod, Chris
Following decades of mining impacts, South America’s hypersaline wetlands (salars)face increasing threats from lithium extraction to support global decarbonisation.Although globally important, salars are understudied and information needed tounderstand environmental impacts is lacking. Modern ecological studies on salarshave focused on microbial community composition and function but other taxa areless studied, including resident and migratory reptiles and birds and their aquaticinvertebrate prey.Given the scale and immediate nature of the threats associated with lithiumexploitation, we must deepen our understanding of salar biology, but this is impededby logistic/financial restrictions given the heightened costs of sampling in these oftenremote, extreme environments. Given the pressing demand for information, wecollated/analysed information from the literature. We generated lists of invertebratetaxa present in 63 hypersaline environments from Argentina, Bolivia, Chile andPeru, and examined relationships between invertebrate community structure andphysicochemical factors. We recorded 46 different taxa, with the Centropagidae beingthe most frequently recorded taxon across systems. Multivariate analyses of communitystructure showed significant clustering among sites. Variation in community structurewas best explained by maximum salinity (18%). Geographical location or ecosystemsize had no obvious effect on community structure. We provide a useful broad view ofaquatic invertebrate diversity in the hypersaline salars but highlight the general lack ofinformation regarding the ecology of these ecosystems
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
High Prevalence and Genetic Diversity of Human Norovirus Among Children Under 5 Years Old with Acute Gastroenteritis at the Dr. Leonardo Guzmán Regional Hospital, Antofagasta, Chile, 2019
(MDPI, 2025) Avellaneda, Andrea M; Campillay-Veliz, Claudia P; Reyes, Daniela C; Herrera, Daniel; Munoz, Christian A; Vinje, Jan; Lay, Margarita K
Acute gastroenteritis (AGE) has one of the highest rates of morbidity and mortality among children under five years old worldwide. It is estimated that 1.7 billion cases of childhood diarrheal diseases occur annually, leading to up to 443,832 deaths. Approximately 90% of these cases are viral, with human norovirus being the main cause in countries that have implemented rotavirus vaccines. The objective of this study was to describe the prevalence and genetic diversity of norovirus in child outpatients and inpatients under five years old at the Regional Hospital of Antofagasta. From 1 January to 31 October 2019, a total of 121 stool samples were collected to detect the presence of norovirus GI and GII using Taqman™-based real-time RT-PCR. Norovirus RNA was detected in 50 (41.3%) samples, of which 96% were typed as GII.4 Sydney (42% GII.4 Sydney[P16] and 54% GII.4 Sydney[P4 New Orleans]). Furthermore, most (92%) of the positive specimens were from children under two years of age and a majority were detected in April (38%) and May (20%). Our findings highlight the high burden of norovirus in hospitalized children with AGE and the importance of molecular strain surveillance to support vaccine development.
Patterns of Insect Distribution in Fruit Trees of South Romania and Their Role as Bacterial Vectors
(MDPI, 2025) Copoiu, Dana S; Lavin, Paris; Itcus, Corina; Purcarea, Cristina
This study is the first investigation of tree–insect–bacteria interactions in south‑ern Romania, documenting the distribution of 19 insect species across various fruit treesand their insect‑associated bacterial diversity. Insect species were identified through DNAbarcoding, while bacterial communities inAnthomyia,Botanophila,Drosophila, andScapto‑myzainsects were analyzed via 16S rRNA gene sequencing. Insect diversity varied acrossapple, cherry, plum, peach, and quince trees, with most species showing tree‑specific distri‑bution, except forDrosophila melanogaster, which was found on all tree species. Its presencewas primarily influenced by fruit development stages rather than temperature changes.Insect bacterial communities comprised 51 genera across four phyla, predominantlyPseu‑domonadotaandBacillota, that varied by tree species rather than insect species, suggestingthe potential role of these flies as bacterial vectors. Several potential pathogenic bacterialgenera were identified as biomarkers within insect microbiomes, suggesting their involve‑ment in disease transmission, particularly affecting apple and cherry trees. This study alsoprovides the first report of seven insect species in Romania, being the first microbiomecharacterization of four dipteran species associated with regional fruit trees
Peatland Pond Microbiome and Biogeochemical Responses to Solar Radiation Extremes in a High-Altitude Wetland, Salar de Huasco, Chile
(MDPI, 2025) Eissler, Yoanna; Yanez-Montalvo, Alfredo; Celis-Pla, Paula S. M; Cornejo-D'Ottone, Marcela; Trabal, Andres; Dorador, Cristina; Piccini, Claudia; Falcon, Luisa I; Romero, Carlos; Aguilar-Munoz, Polette; Molina, Veronica
High-altitude wetland holds unique peatland ponds subjected to extreme diel environmental condition changes. Herein, we evaluate the response of photoautotrophic and nitrification activities and compare it with bacteria and archaea composition shifts in sediment and water changes during key hours of the day. Results indicate the presence of photo-inhibition, including ammonia oxidizers, but a high recovery of photosynthetic activities in the microbial mat and of potential specific functional groups towards the afternoon. The microbial community was composed of 45 phyla, mainly proteobacteria from Alpha-, Delta-, and Gammaproteobacteria and Bacteroidota in the water and sediments, and these later groups were notoriously enriched during the afternoon. The microbial community composition changes were associated with chlorophyll a, nutrients, and greenhouse gases reservoir variability, including methane potential release towards the atmosphere at hours of high radiation. Peatland pond microbial communities and their biogeochemical contribution change in a complex interplay coupled by time to environmental conditions predominantly driven by the extreme solar radiation.
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.
Sustainable biocementation of mine tailings: Reduction of urea requirements through bicarbonate-based MICP
(Elsevier, 2025) Zuniga-Barra, Hector; Pardo-Vasquez, Camila; Velastegui, Edgar; Martinez-Ruano, Jimmy Anderson; Rivas, Mariella; Jeison, David
Microbially induced calcite precipitation (MICP) has emerged as a promising technique to contribute to a more sustainable management of mine tailings deposits. While ureolytic activity has been the predominant driver of conventional MICP to date, the associated release of ammonia poses significant environmental hazards. This study explores a novel, environmentally friendly approach by replacing urea with sodium bicarbonate as the carbon source for MICP, with the aim of reducing urea requirements and thus ammonia release. Leveraging the principles of the MICP, it was observed that when urea concentration was reduced to 0.7 M, by replacing it with bicarbonate, surface strength was close to 400 kPa. Furthermore, wind tunnel testing showed a significant reduction in dust emission, where the mass loss rate of the biocemented sample was below 10 kg m⁻ 2 h⁻ 1 , which means a 9-fold reduction compared to untreated samples. So, it was demonstrated that bicarbonate can effectively replace urea, achieving a relevant reduction of up to 75 % in urea use without compromising the surface strength of the biocemented tailings and reducing the environmental hazards of ammonia release. These results highlight the potential of bicarbonate-based MICP as an innovative and sustainable approach to mitigate the environmental impacts associated with tailings deposits.
Role of human herpesvirus homologs of infected cell protein 27 (ICP27) in the biogenesis, processing, and maturation of mRNAs
(American Society for Microbiology, 2025) Soto-Machuca, Abel A; Ortiz, Gerardo E; Carbone-Schellman, Javier; Pasten-Ferrada, Ignacio A; Retamal-Diaz, Angello; Kalergis, Alexis M; Gonzalez, Pablo A
Herpesviruses are enveloped viruses with large double-stranded DNAgenomes that are highly prevalent in the human population and elicit numeroustypes of clinical manifestations, from mild to severe. These viruses are classified intothree subfamilies: alpha-, beta-, and gammaherpesvirinae, all capable of establishinglife-long persistent infections in the host. As strict intracellular parasites, these viruseshave evolved molecular determinants to support and modulate viral and host genetranscription processes during infection and the translation of messenger RNAs (mRNAs)to synthesize proteins that participate in cellular pathways promoting their replicationcycles and virion formation. Notably, some of these proteins have functional RNA-binding domains consisting of arginine-glycine-glycine (RGG) amino acid (aa) sequencesthat, when methylated, regulate their nucleic acid-binding capacities and can influencethe export of mRNAs lacking introns from the nucleus into the cytoplasm. Additionaldomains and motifs in these proteins mediate their interactions with regulatory proteinsrelated to RNA splicing, either promoting or repressing mRNA processing. Notably, allhuman herpesviruses (HHVs) encode in their genomes proteins that share homologywith infected cell protein 27 (ICP27) of herpes simplex virus type 1 (HSV-1), which cansignificantly impact the biogenesis of mRNAs and their processing during infection. Here,we review and discuss the roles of ICP27 and the corresponding homologs encoded indifferent human herpesviruses, focusing on their similarities and differences in structureand function. A more profound knowledge of the role of key viral factors requiredfor effective herpesvirus replication could aid in the design and identification of novelantivirals to treat the diseases produced by these viruses.
Organ-specific bacterial communities of the soft-shell clam Mya arenaria (Linnaeus, 1758) and adjacent sediments in the Black Sea
(Frontiers Media SA, 2025) Menabit, Selma; Lavin, Paris; Begun, Tatiana; Teaca, Adrian; Muresan, Mihaela; Purcarea, Cristina
Bacteria colonizing bivalves play a critical role in host health by supporting digestion, nutrient cycling, and immune defense. While the microbiomes of marine bivalves have been studied globally, their diversity and functional roles across specific organs remain underexplored. This study investigates the structural and predicted functional diversity of bacterial communities associated with different organs (siphon, gills, and stomach) of the marine bivalve Mya arenaria Linnaeus, 1758, along with the surrounding sediments from the Romanian Black Sea coast, using 16S rRNA gene sequencing with Illumina technology. Bacterial communities within the bivalve differed markedly from those in the sediments and varied across organs. Sediment samples exhibited greater taxonomic diversity (19 phyla) than bivalve organs (14–15 phyla). Verrucomicrobiota dominated the siphon and gills, Spirochaetota were most abundant in the stomach, and Desulfobacterota predominated in sediments. Nitrate-reducing bacteria, particularly those from the genus Persicirhabdus, were prevalent in all organs and may contribute to host resilience under hypoxic conditions. The presence of Sulfurimonas in the stomach suggests a possible nutritional association, while halotolerant Woeseia species identified in sediments likely play a role in environmental nutrient cycling. Predictive functional profiling indicated potential bacterial involvement in various metabolic processes, including carbohydrate, amino acid, and energy metabolism. Additionally, pathways related to xenobiotic degradation and antibiotic biosynthesis were inferred across all sample types, indicating a potential capacity for broader ecological and possibly
HSV-1 alters lipid metabolism and induces lipid droplet accumulation in functionally impaired mouse dendritic cells
(Cell Press, 2025) Farias, Monica A; Cancino, Felipe A; Navarro, Areli J; Duarte, Luisa F; Soto, Abel A; Tognarelli, Eduardo I; Ramm, Maximiliano J; Alarcon-Zapata, Barbara N; Cordero, Jose; Martin, Sergio San; Agurto-Munoz, Cristian; Retamal-Diaz, Angello; Riedel, Claudia A; Barrera, Nelson P; Bustamante, Luis; Bueno, Susan M; Kalergis, Alexis M; Gonzalez, Pablo A
Herpes simplex virus type 1 (HSV-1) significantly impairs dendritic cell (DC) function, ultimately eliciting the death of these cells. Here, we sought to assess whether HSV-1 modulates lipid metabolism in mouse DCs as a mechanism of immune evasion. For this, we performed RT-qPCR gene arrays with ingenuity pathway analysis (IPA), RNA sequencing (RNA-seq) and gene set enrichment analysis (GSEA), confocal microscopy, transmission electron microscopy, ultra-high-performance liquid chromatography-quadrupole time-of-flight (UHPLC-QTOF) analysis, pharmacological inhibition of eight lipid-metabolism-related enzymes in HSV-1-infected DCs, co-cultures between virus-specific transgenic CD4+ and CD8+ T cells and HSV-1-infected DCs, and in vivo assays with mice. We found that HSV-1 significantly alters lipid metabolism in DCs and induces lipid droplet (LD) accumulation in these cells. Pharmacological inhibition of two particular lipid metabolism enzymes was found to partially restore DC function. Overall, these results suggest that lipid metabolism plays an important role in the impairment of DC function by HSV-1.
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.
Marine picoplankton metagenomes and MaGs from eleven vertical profiles obtained by the Malaspina Expedition
(Nature Research, 2024) Sánchez, Pablo; Coutinho, Felipe H.; Sebastián, Marta; Pernice, Massimo C.; Rodríguez Martínez, Raquel; Salazar, Guillem; Cornejo Castillo, Francisco Miguel; Pesant, Stéphane; López-Alforja, Xabier; López-García, Ester María; Agustí, Susana; Gojobori, Takashi; Logares, Ramiro; Sala, Maria Montserrat; Vaqué, Dolors; Massana, Ramon; Duarte, Carlos M.; Acinas, Silvia G.; Gasol, Josep M.
The Ocean microbiome has a crucial role in Earth’s biogeochemical cycles. During the last decade, global cruises such as Tara Oceans and the Malaspina Expedition have expanded our understanding of the diversity and genetic repertoire of marine microbes. Nevertheless, there are still knowledge gaps regarding their diversity patterns throughout depth gradients ranging from the surface to the deep ocean. Here we present a dataset of 76 microbial metagenomes (MProfile) of the picoplankton size fraction (0.2–3.0 μm) collected in 11 vertical profiles covering contrasting ocean regions sampled during the Malaspina Expedition circumnavigation (7 depths, from surface to 4,000 m deep). The MProfile dataset produced 1.66 Tbp of raw DNA sequences from which we derived: 17.4 million genes clustered at 95% sequence similarity (M-GeneDB-VP), 2,672 metagenome-assembled genomes (MAGs) of Archaea and Bacteria (Malaspina-VP-MAGs), and over 100,000 viral genomic sequences. This dataset will be a valuable resource for exploring the functional and taxonomic connectivity between the photic and bathypelagic tropical and sub-tropical ocean, while increasing our general knowledge of the Ocean microbiome.
MICP mediated by indigenous bacteria isolated from tailings for biocementation for reduction of wind erosion
(Frontiers Media SA, 2024) Maureira, Alejandro; Zapata, Manuel; Olave, Jorge; Jeison, David; Wong, Liey-Si; Panico, Antonio; Hernández, Pía
In this study, native ureolytic bacteria were isolated from copper tailings soils to perform microbial-induced carbonate precipitation (MICP) tests and evaluate their potential for biocement formation and their contribution to reduce th dispersion of particulate matter into the environment from tailings containing potentially toxic elements. It was possible to isolate a total of 46 bacteria; among them only three showed ureolytic activity: Priestia megaterium T130-1, Paenibacillus sp. T130-13 and Staphylococcus sp. T130-14. Biocement cores were made by mixing tailings with the isolated bacteria in presence of urea, resulting similar to those obtained with Sporosarcina pasteurii and Bacillus subtilis used as positive control. Indeed, XRD analysis conducted on biocement showed the presence of microcline (B. subtilis 17%; P. megaterium 11. 9%), clinochlore (S.pasteurii, 6.9%) and magnesiumhornblende (Paenibacillus sp. 17.8%; P. megaterium 14.6%); all these compounds were not initially present in the tailings soils. Moreover the presence of calcite (control 0.828%; Paenibacillus sp. 5.4%) and hematite (control 0.989%; B. subtilis 6.4%) was also significant unlike the untreated control. The development of biofilms containing abundant amount of Ca, C, andOon microscopic soil particles was evidenced by means of FE-SEMEDX and XRD. Wind tunnel tests were carried out to investigate the resistance of biocement samples, accounted for a mass loss five holds lower than the control, i.e., the rate of wind erosion in the control corresponded to 82 g/m2h while for the biocement treated with Paenibacillus sp. it corresponded to only 16.371 g/m2h. Finally, in compression tests, the biocement samples prepared with P. megaterium (28.578 psi) and Paenibacillus sp. (28.404 psi) showed values similar to those obtained with S. pasteurii (27.102 psi), but significantly higher if compared to the control (15.427 psi), thus improving the compression resistance capacity of the samples by 85.2% and 84.1% with respect to the control. According to the results obtained, the biocement samples generated with the native strains showed improvements in the mechanical properties of the soil supporting them as potential candidates in applications for the stabilization of mining liabilities in open environments using bioaugmentation strategies with native strains isolated from the same mine tailing.
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.
Whole-genome sequencing of a Janthinobacterium sp. isolatedfrom the Patagonian Desert
(American Society For Microbiology, 2024) Cavanaugh, Nicole T.; Kumar, Girish; Reverdy Pearson, Alicyn; Colbert, Julia; Riquelme, Carlos; Hudson, André O.; Chai, Yunrong; Godoy Carter, Veronica
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.
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.
Secondary metabolites with antimicrobial activity produced by thermophilic bacteria from a high-altitude hydrothermal system
(Frontiers Media SA, 2024) Pardo Esté, Coral; Cortés, Johanna; Castro Severyn, Juan; Pérez, Vilma; Henriquez Aedo, Karem; Cuadros, Fabian; Yañez, Carolina; Cuadros Orellana, Sara; Dorador, Cristina; Molina, Veronica; Eissler, Yoanna; Paquis, Pablo; Jeffrey, Wade H.; Pozo, Patricia; Pérez, Pablo A.; Hengst, Martha B.
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
(Frontiers Media SA, 2024) Menabit, Selma ; Lavin, Paris ; Begun, Tatiana ; Mihaela Mureșan ; Teacӑ, Adrian; Purcarea, Cristina
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.

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