Facultad de Ciencias de la Vida

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http://repositorio.unab.cl//handle/ria/2068

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En 2018 se fusionan la Facultad de Ciencias Biológicas, con la Facultad de Ecología y Recursos Naturales y se crea la Facultad de Ciencias de la Vida (Fac.CV)

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11-Deoxycorticosterone (DOC)’s Action on the Gill Osmoregulation of Juvenile Rainbow Trout (Oncorhynchus mykiss)
(MDPI, 2024-02-02) Zuloaga, Rodrigo; Ahumada-Langer, Luciano; Aedo, Jorge Eduardo; Molina, Alfredo; Valdés, Juan Antonio
In aquaculture, stress can negatively affect fish growth. For years, the cortisol hormone has been thought to play both glucocorticoid and mineralocorticoid functions. Nevertheless, recent research has suggested that 11-deoxycorticosterone (DOC) released during stress could contribute to cortisol actions, though this process is still misunderstood. Here, we evaluated the DOC effects on physiological and early transcriptional responses by RNA-seq. Juvenile rainbow trout were treated with DOC and/or glucocorticoids (mifepristone) or mineralocorticoid (eplerenone) receptor antagonists. Subsequently, plasma was collected, and cDNA libraries were generated from the gills of vehicle (control), DOC, mifepristone, mifepristone with DOC, eplerenone, and eplerenone with DOC groups. Calcium and phosphate levels in plasma were changed. Results revealed 914 differentially expressed transcripts (DETs) induced by DOC compared with control, mainly associated with sodium ion transmembrane transport, gluconeogenesis, negative regulation of transmembrane transport, and activation of innate immune response. DOC versus eplerenone with DOC comparison displayed 444 DETs related to cell-cell junction organization, canonical glycolysis, positive regulation of immune response, and potassium ion transport. Conversely, no DETs were detected in DOC versus mifepristone with DOC comparison. These data suggest that DOC has a relevant role in gill stress response and ion transport, which is differentially regulated by mineralocorticoid receptors.
2-(2-pyridylamino)pyridinium tetrachloridozincate(II)
(International Union of Crystallography, 2008-06-01) Venegas-Yazigi, Diego; Castillo, Carolina; Paredes-Garcia, Veronica; Vega, Andres; Spodine, Evgenia
The structure of the title compound, (C10H10N3)(2)[ZnCl4], is composed of C10H9N3H+ ( DPAH(+)) cations and [ ZnCl4](2-) anions. The two pyridyl rings of DPAH+ are approximately coplanar, with a dihedral angle of 7.2 ( 2)degrees between their corresponding least-squares planes. The proton is disordered in a one-to-one ratio over the two chemically equivalent pyridyl N atoms. An intramolecular hydrogen bond is formed between the pyridinium H atom and the pyridyl N atom of the other pyridyl ring. The Zn atom lies on a twofold rotation axis. There are also some weak N-H center dot center dot center dot Cl hydrogen bonds. These interactions lead to the formation of an alternating zigzag chain in the solid state. The results clearly show that reducing agents normally used in hydrothermal syntheses, such as metallic zinc employed here, are also active in terms of coordination chemistry.
50 Years of Cetacean Strandings Reveal a Concerning Rise in Chilean Patagonia
(Nature Research, 2020-12) Alvarado-Rybak M.; Toro F.; Escobar-Dodero J.; Kinsley A.C.; Sepúlveda M.A.; Capella J.; Azat C.; Cortés-Hinojosa G.; Zimin-Veselkoff N.; Mardones F.O.
Cetacean strandings (CS) have been reported in increasing numbers in coastal areas worldwide. Although the causes of these strandings are unknown, a number of anthropogenic and environmental factors have been suggested. This paper aims to characterize CS patterns and describe their fine-scale spatiotemporal dynamics. We analysed spatial and spatiotemporal CS patterns in Chile from January 1968 to January 2020. We identified a total of 389 CS events affecting eight cetacean families, 21 genera, and 35 species, which represent more than 85% of the reported species richness for the country. Most CS events (94.1%) were single (i.e., ≤two individuals). There were also 18 mass stranding (three to 24 individuals, 4.1%) and nine unusually large mass stranding events (>25 individuals, 2%). Purely spatial tests showed CS events appearing in random occurrence along the Chilean coast. Local tests for spatio-temporal clusters, however, identified a greater number of hotspots reported in the southernmost part of the country, namely, Chilean Patagonia. Specifically, significant spatio-temporal clusters were identified and defined as containing three or more individuals within a two-month period as a focal coastal event (<1 km radius). It is a cause of concern that CS events in Chile have been increasing consistently over the last decades, and although we were not able to identify their causes, we are able to highlight the importance of changes in climate conditions and of an increase in monitoring activities as primary drivers for such patterns, particularly important in Chilean Patagonia. © 2020, The Author(s).
9,10-dihydroxy-4,4-dimethyl-5,8-dihydroanthracen-1(4H)-one
(International Union of Crystallography, 2008-07-01) Ramirez-Rodriguez, Oney; Martinez-Cifuentes, Maximiliano; Ibanez, Andres; Vega, Andres; Araya-Maturana, Ramiro
In the title molecule, C16H16O3, the ring system is planar and an intramolecular hydrogen bond is present. The molecular packing is dominated by an intermolecular hydrogen bond and by pi-stacking interactions [interplanar separation 3.8012 angstrom].
A bibiliometric analysis of the Journal of Infection and Public Health: 2008–2016
(Elsevier Ltd, 2018-03) Krauskopf, Erwin
Background: The Journal of Infection and Public Health published its first issue in 2008. The fact that the journal has been published uninterruptedly as well as its editorial content and the application of a peer-review process to select manuscripts, made the journal eligible to be indexed by databases such as Scopus. This study presents a general overview of the journal from 2008 until 2016 using bibliometric indicators to assess its performance. Methods: The data for this study, dating between 2008 and 2016, was extracted from Scopus database. All the information was exported in CSV format to the Sequel Pro software for data analysis. Additionally, collaboration and word co-occurrence networks were generated using VOSviewer. Results: The total number of documents published between 2008–2016 was 586, of which local authorship (Saudi Arabia) constituted a small share, accounting only for 19.3% (113 documents). Those with foreign authorship (other countries excluding Saudi Arabia) represented 80.7% (473) of the total. Furthermore, the three countries that co-author documents with researchers from Saudi Arabia are Egypt, the United States and the United Kingdom. Likewise, these three countries serve as nodes connecting researchers from other countries located in Asia, Africa, Europe and Latin America. An analysis of the top-five journals that cited the research published revealed that that 90.2% of them belonged to the first and second quartiles confirms the quality of the research being published. Word co-occurrence analysis established a slight shift of focus in the research topics published during the last four years studied, as a new cluster was formed with terms related to “education”, “intervention” and “implementation”. Conclusion: The journal has managed, in very few years, to be considered by researchers worldwide. Furthermore, throughout the years, the journal showed an evolution in the main topics covered, providing a contemporary overview of public health. © 2018
A cell surface arabinogalactan-peptide influences root hair cell fate
(Blackwell Publishing Ltd, 2020-08) Borassi, C.; Gloazzo Dorosz, J.; Ricardi, M.M.; Carignani Sardoy, M.; Pol Fachin, L.; Marzol E.; Mangano, S.; Rodríguez Garcia, D.R.; Martínez Pacheco, J.; Rondón Guerrero, Y.D.C.; Velasquez, S.M.; Villavicencio, B.
Root hairs (RHs) develop from specialized epidermal trichoblast cells, whereas epidermal cells that lack RHs are known as atrichoblasts. The mechanism controlling RH cell fate is only partially understood. RH cell fate is regulated by a transcription factor complex that promotes the expression of the homeodomain protein GLABRA 2 (GL2), which blocks RH development by inhibiting ROOT HAIR DEFECTIVE 6 (RHD6). Suppression of GL2 expression activates RHD6, a series of downstream TFs including ROOT HAIR DEFECTIVE 6 LIKE-4 (RSL4) and their target genes, and causes epidermal cells to develop into RHs. Brassinosteroids (BRs) influence RH cell fate. In the absence of BRs, phosphorylated BIN2 (a Type-II GSK3-like kinase) inhibits a protein complex that regulates GL2 expression. Perturbation of the arabinogalactan peptide (AGP21) in Arabidopsis thaliana triggers aberrant RH development, similar to that observed in plants with defective BR signaling. We reveal that an O-glycosylated AGP21 peptide, which is positively regulated by BZR1, a transcription factor activated by BR signaling, affects RH cell fate by altering GL2 expression in a BIN2-dependent manner. Changes in cell surface AGP disrupts BR responses and inhibits the downstream effect of BIN2 on the RH repressor GL2 in root epidermis. © 2020 The Authors. New Phytologist © 2020 New Phytologist Trust
A Comparative Study of the Synthesis and Characterization of Biogenic Selenium Nanoparticles by Two Contrasting Endophytic Selenobacteria
(MDPI, 2023-06) Sans-Serramitjana, Eulàlia; Gallardo-Benavente, Carla; Melo, Francisco; Pérez-Donoso, José M.; Rumpel, Cornelia; Barra, Patricio Javier; Durán, Paola; Mora, María de La Luz
The present study examined the biosynthesis and characterization of selenium nanoparticles (SeNPs) using two contrasting endophytic selenobacteria, one Gram-positive (Bacillus sp. E5 identified as Bacillus paranthracis) and one Gram-negative (Enterobacter sp. EC5.2 identified as Enterobacter ludwigi), for further use as biofortifying agents and/or for other biotechnological purposes. We demonstrated that, upon regulating culture conditions and selenite exposure time, both strains were suitable “cell factories” for producing SeNPs (B-SeNPs from B. paranthracis and E-SeNPs from E. ludwigii) with different properties. Briefly, dynamic light scattering (DLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) studies revealed that intracellular E-SeNPs (56.23 ± 4.85 nm) were smaller in diameter than B-SeNPs (83.44 ± 2.90 nm) and that both formulations were located in the surrounding medium or bound to the cell wall. AFM images indicated the absence of relevant variations in bacterial volume and shape and revealed the existence of layers of peptidoglycan surrounding the bacterial cell wall under the conditions of biosynthesis, particularly in the case of B. paranthracis. Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) showed that SeNPs were surrounded by the proteins, lipids, and polysaccharides of bacterial cells and that the numbers of the functional groups present in B-SeNPs were higher than in E-SeNPs. Thus, considering that these findings support the suitability of these two endophytic stains as potential biocatalysts to produce high-quality Se-based nanoparticles, our future efforts must be focused on the evaluation of their bioactivity, as well as on the determination of how the different features of each SeNP modulate their biological action and their stability. © 2023 by the authors.
A feed-forward loop between SroC and MgrR small RNAs modulates the expression of eptB and the susceptibility to polymyxin B in Salmonella Typhimurium
(Microbiology Society, 2016-11) Acuña, Lillian G.; Barros, M. José; Peñaloza, Diego; Rodas, Paula I.; Paredes-Sabja, Daniel; Fuentes, Juan A.; Gil, Fernando; Calderón, Iván L.
Base-pairing small RNAs (sRNAs) regulate gene expression commonly by direct interaction with cognate mRNAs. Nevertheless, recent studies have expanded this knowledge with the discovery of the RNA ‘sponges’ which are able to interact and repress the functions of classical base-pairing sRNAs. In this work, we present evidence indicating that the sponge RNA SroC from Salmonella enterica serovar Typhimurium base pairs with the MgrR sRNA, thereby antagonizing its regulatory effects on both gene expression and resistance to the antimicrobial peptide polymyxin B (PMB). By a predictive algorithm, we determined putative SroC–MgrR base-pairing regions flanking the interaction area between MgrR and its target mRNA, eptB, encoding a LPS-modifying enzyme. With a two-plasmid system and compensatory mutations, we confirmed that SroC directly interacts and down-regulates the levels of MgrR, thus relieving the MgrR-mediated repression of eptB mRNA. Since it was previously shown that an Escherichia coli strain carrying an mgrR deletion is more resistant to PMB, we assessed the significance of SroC in the susceptibility of S. Typhimurium to PMB. Whereas the sroC deletion increased the sensitivity to PMB, as compared to the wild-type, the resistance phenotypes between the DmgrR and DsroCDmgrR strains were comparable, evidencing that mgrR mutation is epistatic to the sroC mutation. Together, these results indicate that both SroC and MgrR sRNAs compose a coherent feed-forward loop controlling the eptB expression and hence the LPS modification in S. Typhimurium.
A First Insight into the Microbial and Viral Communities of Comau Fjord—A Unique Human-Impacted Ecosystem in Patagonia (42° S)
(MDPI, 2023-03) Guajardo-Leiva, Sergio; Mendez, Katterinne N.; Meneses, Claudio; Díez, Beatriz; Castro-Nallar, Eduardo
While progress has been made in surveying the oceans to understand microbial and viral communities, the coastal ocean and, specifically, estuarine waters, where the effects of anthropogenic activity are greatest, remain partially understudied. The coastal waters of Northern Patagonia are of interest since this region experiences high-density salmon farming as well as other disturbances such as maritime transport of humans and cargo. Here, we hypothesized that viral and microbial communities from the Comau Fjord would be distinct from those collected in global surveys yet would have the distinctive features of microbes from coastal and temperate regions. We further hypothesized that microbial communities will be functionally enriched in antibiotic resistance genes (ARGs) in general and in those related to salmon farming in particular. Here, the analysis of metagenomes and viromes obtained for three surface water sites showed that the structure of the microbial communities was distinct in comparison to global surveys such as the Tara Ocean, though their composition converges with that of cosmopolitan marine microbes belonging to Proteobacteria, Bacteroidetes, and Actinobacteria. Similarly, viral communities were also divergent in structure and composition but matched known viral members from North America and the southern oceans. Microbial communities were functionally enriched in ARGs dominated by beta-lactams and tetracyclines, bacitracin, and the group macrolide–lincosamide–streptogramin (MLS) but were not different from other communities from the South Atlantic, South Pacific, and Southern Oceans. Similarly, viral communities were characterized by exhibiting protein clusters similar to those described globally (Tara Oceans Virome); however, Comau Fjord viromes displayed up to 50% uniqueness in their protein content. Altogether, our results indicate that microbial and viral communities from the Comau Fjord are a reservoir of untapped diversity and that, given the increasing anthropogenic impacts in the region, they warrant further study, specifically regarding resilience and resistance against antimicrobials and hydrocarbons. © 2023 by the authors.
A folding reaction at the C-terminal domain drives temperature sensing in TRPM8 channels
(National Academy of Sciences, 2020-08) Díaz-Franulic, Ignacio; Raddatz, Natalia; Castillo, Karen; González-Nilo, Fernando D.; Latorre, Ramon
In mammals, temperature-sensitive TRP channels make membrane conductance of cells extremely temperature dependent, allowing the detection of temperature ranging from noxious cold to noxious heat. We progressively deleted the distal carboxyl terminus domain (CTD) of the cold-activated melastatin receptor channel, TRPM8. We found that the enthalpy change associated with channel gating is proportional to the length of the CTD. Deletion of the last 36 amino acids of the CTD transforms TRPM8 into a reduced temperature-sensitivity channel (Q10 ∼4). Exposing the intracellular domain to a denaturing agent increases the energy required to open the channel indicating that cold drives channel gating by stabilizing the folded state of the CTD. Experiments in the presence of an osmoticant agent suggest that channel gating involves a change in solute-inaccessible volume in the CTD of ∼1,900 Å3. This volume matches the void space inside the coiled coil according to the cryogenic electron microscopy structure of TRPM8. The results indicate that a folding–unfolding reaction of a specialized temperature-sensitive structure is coupled to TRPM8 gating.
A functional IL1RL1 variant regulates corticosteroid-induced sST2 expression in ulcerative colitis
(Nature Publishing Group, 2017-12) Díaz-Jiménez, D.; Núñez, L.; De La Fuente, M.; Dubois-Camacho, K.; Sepúlveda, H.; Montecino, M.; Torres-Riquelme, A.; García-González, P.; Chnaiderman, J.; Vossenkamper, A.; MacDonald, T.T.; Simian, D.; González, M.; Cidlowski, J.A.; Quera, R.; Hermoso, M.A.
The ST2/IL33 signalling pathway has been associated with ulcerative colitis (UC). ST2, encoded by the IL1RL1 gene, is expressed as both a membrane-anchored receptor (ST2L) activated by IL33 and as a soluble receptor (sST2) with anti-inflammatory properties. In UC patients, sST2 is further increased by corticosteroid treatment; however, the glucocorticoid-mediated molecular regulation remains unknown. We therefore tested whether genetic variants in the IL1RL1 distal promoter are involved in UC and affect glucocorticoid-mediated ST2 expression. Serum ST2 levels and genetic variants in the IL1RL1 distal promoter were examined by ELISA and PCR sequencing in UC patients receiving corticosteroids. Glucocorticoid-mediated ST2 production was evaluated in intestinal mucosa cultures. Molecular regulation of glucocorticoid-mediated ST2 was assessed by RT-qPCR, ChIP assay and luciferase reporter assay. Dexamethasone effect on ST2 transcript expression was analyzed in leukocytes and related to IL1RL1 variants. Sequencing of a distal IL1RL1 promoter region demonstrated that SNPs rs6543115(C) and rs6543116(A) are associated with increased sST2 in UC patients on corticosteroids. Dexamethasone up-regulated sST2 transcription through interaction with the glucocorticoid-response element (GRE) carrying rs6543115(C) variant. Our data indicate that IL1RL1 SNPs rs6543115(C) confer susceptibility to UC and is contained in the GRE, which may modulate glucocorticoid-induced sST2 expression.
A global map of suitability for coastal Vibrio cholerae under current and future climate conditions
(Elsevier, 2015-09) Escobar, Luis E.; Ryan, Sadie J.; Stewart-Ibarra, Anna M.; Finkelstein, Julia L.; King, Christine A.; Qiao, Huijie; Polhemus, Mark E.
Vibrio cholerae is a globally distributed water-borne pathogen that causes severe diarrheal disease and mortality, with current outbreaks as part of the seventh pandemic. Further understanding of the role of environmental factors in potential pathogen distribution and corresponding V. cholerae disease transmission over time and space is urgently needed to target surveillance of cholera and other climate and water-sensitive diseases. We used an ecological niche model (ENM) to identify environmental variables associated with V. cholerae presence in marine environments, to project a global model of V. cholerae distribution in ocean waters under current and future climate scenarios. We generated an ENM using published reports of V. cholerae in seawater and freely available remotely sensed imagery. Models indicated that factors associated with V. cholerae presence included chlorophyll-a, pH, and sea surface temperature (SST), with chlorophyll-a demonstrating the greatest explanatory power from variables selected for model calibration. We identified specific geographic areas for potential V. cholerae distribution. Coastal Bangladesh, where cholera is endemic, was found to be environmentally similar to coastal areas in Latin America. In a conservative climate change scenario, we observed a predicted increase in areas with environmental conditions suitable for V. cholerae. Findings highlight the potential for vulnerability maps to inform cholera surveillance, early warning systems, and disease prevention and control. © 2015 The Authors.
A global metagenomic map of urban microbiomes and antimicrobial resistance
(Elsevier B.V., 2021-06-24) Danko, David; Bezdan, Daniela; Afshin, Evan E.; Ahsanuddin, Sofia; Bhattacharya, Chandrima; Butler, Daniel J.; Chng, Kern Rei; Donnellan, Daisy; Hecht, Jochen; Jackson, Katelyn; Kuchin, Katerina; Karasikov, Mikhai
We present a global atlas of 4,728 metagenomic samples from mass-transit systems in 60 cities over 3 years, representing the first systematic, worldwide catalog of the urban microbial ecosystem. This atlas provides an annotated, geospatial profile of microbial strains, functional characteristics, antimicrobial resistance (AMR) markers, and genetic elements, including 10,928 viruses, 1,302 bacteria, 2 archaea, and 838,532 CRISPR arrays not found in reference databases. We identified 4,246 known species of urban microorganisms and a consistent set of 31 species found in 97% of samples that were distinct from human commensal organisms. Profiles of AMR genes varied widely in type and density across cities. Cities showed distinct microbial taxonomic signatures that were driven by climate and geographic differences. These results constitute a high-resolution global metagenomic atlas that enables discovery of organisms and genes, highlights potential public health and forensic applications, and provides a culture-independent view of AMR burden in cities.
A global review of the American mink (Neovison vison) removal techniques – Patagonia as a case study for their potential application
(Universidad de Concepcion, 2023-06) López, Ronar; Clapperton, B. Kay; Medina-Vogel, Gonzalo
American mink (Neovison vison) represents a threat to both biodiversity and economy in various regions of the world, including Patagonia. This invasive species has been successfully removed from many areas of Europe. In Chile and Argentina there have been only patchily distributed attempts of local control to date and large-scale removal has been considered unfeasible. We analyzed available scientific information, to determine best-fit strategies and improved methodologies that increase efficiency (capture per unit of effort) in American mink control. We reviewed published papers about programs that aimed at local control, functional or total eradication of minks in the Web of Science (WoS) database. Based on accessible information, the influence of some field variables on capture efficiency was determined through a General Lineal Model. From 1525 results in the WoS search, 51 papers refer to mink control action carried out in 28 areas of Europe and South America since 1992. Trapping has been the most used and efficient capture method. Short trapping periods that cover larger lineal distances per control program, and the use of attractants, specifically pheromones, have led to improved control efficiency. Chilean, Scottish and English experiences showed among the highest trapping efficiency values. We identify areas of research needed on mink ecology and behavior and trapping techniques that could improve trapping efficiency. A control program that incorporates the outcomes of this data assessment has the potential to improve feral mink removal. But further research is required to ensure that these efficiency measures result in cost-effective control in Patagonia. © 2023 The author(s).
A high-throughput chemically induced inflammation assay in zebrafish
(BMC, 2010-12-22) d'Alençon, Claudia A.; Peña, Oscar A.; Wittmann, Christine; Gallardo, Viviana E.; Jones, Rebecca A.; Loosli, Felix; Liebel, Urban; Grabher, Clemens; Allende, Miguel L.
Background: Studies on innate immunity have benefited from the introduction of zebrafish as a model system. Transgenic fish expressing fluorescent proteins in leukocyte populations allow direct, quantitative visualization of an inflammatory response in vivo. It has been proposed that this animal model can be used for high-throughput screens aimed at the identification of novel immunomodulatory lead compounds. However, current assays require invasive manipulation of fish individually, thus preventing high-content screening.Results: Here we show that specific, noninvasive damage to lateral line neuromast cells can induce a robust acute inflammatory response. Exposure of fish larvae to sublethal concentrations of copper sulfate selectively damages the sensory hair cell population inducing infiltration of leukocytes to neuromasts within 20 minutes. Inflammation can be assayed in real time using transgenic fish expressing fluorescent proteins in leukocytes or by histochemical assays in fixed larvae. We demonstrate the usefulness of this method for chemical and genetic screens to detect the effect of immunomodulatory compounds and mutations affecting the leukocyte response. Moreover, we transformed the assay into a high-throughput screening method by using a customized automated imaging and processing system that quantifies the magnitude of the inflammatory reaction.Conclusions: This approach allows rapid screening of thousands of compounds or mutagenized zebrafish for effects on inflammation and enables the identification of novel players in the regulation of innate immunity and potential lead compounds toward new immunomodulatory therapies. We have called this method the chemically induced inflammation assay, or ChIn assay.See Commentary article: http://www.biomedcentral.com/1741-7007/8/148. © 2010 d'Alençon et al; licensee BioMed Central Ltd.
A machine-learning regional clustering approach to understand ventilator-induced lung injury: a proof-of-concept experimental study
(Springer Nature, 2024-12) Cruces, Pablo; Retamal, Jaime; Damián, Andrés; Lago, Graciela; Blasina, Fernanda; Oviedo, Vanessa; Medina, Tania; Pérez, Agustín; Vaamonde, Lucía; Dapueto, Rosina; González-Dambrauskas, Sebastian; Serra, Alberto
Background: The spatiotemporal progression and patterns of tissue deformation in ventilator-induced lung injury (VILI) remain understudied. Our aim was to identify lung clusters based on their regional mechanical behavior over space and time in lungs subjected to VILI using machine-learning techniques. Results: Ten anesthetized pigs (27 ± 2 kg) were studied. Eight subjects were analyzed. End-inspiratory and end-expiratory lung computed tomography scans were performed at the beginning and after 12 h of one-hit VILI model. Regional image-based biomechanical analysis was used to determine end-expiratory aeration, tidal recruitment, and volumetric strain for both early and late stages. Clustering analysis was performed using principal component analysis and K-Means algorithms. We identified three different clusters of lung tissue: Stable, Recruitable Unstable, and Non-Recruitable Unstable. End-expiratory aeration, tidal recruitment, and volumetric strain were significantly different between clusters at early stage. At late stage, we found a step loss of end-expiratory aeration among clusters, lowest in Stable, followed by Unstable Recruitable, and highest in the Unstable Non-Recruitable cluster. Volumetric strain remaining unchanged in the Stable cluster, with slight increases in the Recruitable cluster, and strong reduction in the Unstable Non-Recruitable cluster. Conclusions: VILI is a regional and dynamic phenomenon. Using unbiased machine-learning techniques we can identify the coexistence of three functional lung tissue compartments with different spatiotemporal regional biomechanical behavior. © The Author(s) 2024.
A Modeled High-Density Fed-Batch Culture Improves Biomass Growth and β-Glucans Accumulation in Microchloropsis salina
(Plants, 2022-12) Ocaranza, Darío; Balic, Iván; Bruna, Tamara; Moreno, Ignacio; Díaz, Oscar; Moreno, Adrián A.; Caro, Nelson
Algae and microalgae are used as a source of different biomolecules, such as lipids and carbohydrates. Among carbohydrates, polysaccharides, such as β-glucans, are important for their application as antioxidants, antisepsis, and immunomodulators. In the present work, the β-glucans production potential of Microchloropsis salina was assessed using two different culture conditions: a high-density batch and a modeled high-density fed-batch. From the biochemical parameters determined from these two cultures conditions, it was possible to establish that the modeled high density fed-batch culture improves the biomass growth. It was possible to obtain a biomass pro ductivity equal to 8.00 × 10−2 ± 2.00 × 10−3 g/(L × day), while the batch condition reached 5.13 × 10−2 ± 4.00 × 10−4 g/(L × day). The same phenomenon was observed when analyzing the β-glucans accumulation, reaching volumetric productivity equal to 5.96 × 10−3 ± 2.00 × 10−4 g of product/(L × day) against the 4.10 × 10−3 ± 2.00 × 10−4 g of product/(L × day) obtained in batch conditions. These data establish a baseline condition to optimize and significantly increase β-glucan productivity, as well as biomass, adding a new and productive source of this polymer, and integrating its use in potential applications in the human and animal nutraceutical industry.
A Modeled High-Density Fed-Batch Culture Improves Biomass Growth and β-Glucans Accumulation in Microchloropsis salina
(MDPI, 2022-12) Ocaranza, Darío; Balic, Iván; Bruna, Tamara; Moreno, Ignacio; Díaz, Oscar; Moreno, Adrián A.; Caro, Nelson
Algae and microalgae are used as a source of different biomolecules, such as lipids and carbohydrates. Among carbohydrates, polysaccharides, such as β-glucans, are important for their application as antioxidants, antisepsis, and immunomodulators. In the present work, the β-glucans production potential of Microchloropsis salina was assessed using two different culture conditions: a high-density batch and a modeled high-density fed-batch. From the biochemical parameters determined from these two cultures conditions, it was possible to establish that the modeled high-density fed-batch culture improves the biomass growth. It was possible to obtain a biomass productivity equal to 8.00 × 10−2 ± 2.00 × 10−3 g/(L × day), while the batch condition reached 5.13 × 10−2 ± 4.00 × 10−4 g/(L × day). The same phenomenon was observed when analyzing the β-glucans accumulation, reaching volumetric productivity equal to 5.96 × 10−3 ± 2.00 × 10−4 g of product/(L × day) against the 4.10 × 10−3 ± 2.00 × 10−4 g of product/(L × day) obtained in batch conditions. These data establish a baseline condition to optimize and significantly increase β-glucan productivity, as well as biomass, adding a new and productive source of this polymer, and integrating its use in potential applications in the human and animal nutraceutical industry. © 2022 by the authors.
A New Kind of Quinonic-Antibiotic Useful Against Multidrug-Resistant S. aureus and E. faecium Infections
(MDPI AG, 2018-07) Campanini-Salinas, J.; Andrades-Lagos, J.; Gonzalez Rocha, G.; Choquesillo-Lazarte, D.; Bollo Dragnic, S.; Faúndez, M.; Alarcón, P.; Silva, F.; Vidal, R.; Salas-Huenuleo, E.; Kogan, M.; Mella, J.; Recabarren Gajardo, G.; Vásquez-Velásquez, D.
A rapid emergence of resistant bacteria is occurring worldwide, endangering the efficacy of antibiotics and reducing the therapeutic arsenal available for treatment of infectious diseases. In the present study, we developed a new class of compounds with antibacterial activity obtained by a simple, two step synthesis and screened the products for in vitro antibacterial activity against ATCC® strains using the broth microdilution method. The compounds exhibited minimum inhibitory concentrations (MIC) of 1⁻32 μg/mL against Gram-positive ATCC® strains. The structure⁻activity relationship indicated that the thiophenol ring is essential for antibacterial activity and the substituents on the thiophenol ring module, for antibacterial activity. The most promising compounds detected by screening were tested against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VREF) clinical isolates. We found remarkable activity against VREF for compounds 7 and 16, were the MIC50/90 were 2/4 µg/mL and 4/4 µg/mL, respectively, while for vancomycin the MIC50/90 was 256/512 µg/mL. Neither compound affected cell viability in any of the mammalian cell lines at any of the concentrations tested. These in vitro data show that compounds 7 and 16 have an interesting potential to be developed as new antibacterial drugs against infections caused by VREF.
A new population of Darwin's fox (Lycalopex fulvipes) in the Valdivian Coastal Range
(Sociedad de Biología de Chile, 2014) Farias, Ariel A; Sepúlveda, Maximiliano A; Silva-Rodríguez, Eduardo A; Eguren, Antonieta; González, Danilo; Jordán, Natalia I; Ovando, Erwin; Stowhas, Paulina; Svensson, Gabriella L
Darwin's fox (Lycalopex fulvipes Martin, 1837) is an endemic of the temperate forests of the Coastal Range of southern Chile, that was reported by Charles Darwin in 1834 in southern Chiloé Island (42° S, 74° W; Martin 1837). Initially known exclusively from that island, it was considered both an insular subspecies of the chilla fox (Lycalopex griseus Gray, 1837) (Housse 1953; Clutton-Brock et al. 1976) and a valid species (Martin 1837; Gay 1947; Osgood 1943). In 1990, a mainland population was reported at Nahuelbuta National Park (ca. 450 km north of Chiloé Island, 37° 47′ S, 72° 59′ W; Figure 1a) in sympatry with the chilla and culpeo foxes (Lycalopex culpaeus Molina, 1782) (Jaksic et al. 1990; Medel et al. 1990; Jiménez et al. 1991). This supported its status as a valid species, later confirmed through genetic studies (Yahnke et al. 1996).

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