Facultad de Ciencias de la Vida

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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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Detection of antimicrobial-resistant Enterobacterales in insectivorous bats from Chile
(Royal Society Publishing, 0023-11) Rojas-Sereno, Zulma Esperanza; Streicker, Daniel G; Suarez-Yana, Tania; Lineros, Michelle; Yung, Verónica; Godreuil, Sylvain; Benavides, Julio A
Enterobacterales of clinical importance for humans and domestic animals are now commonly detected among wildlife worldwide. However, few studies have investigated their prevalence among bats, particularly in bat species living near humans. In this study, we assessed the occurrence of Extended-spectrum beta-lactamase-producing (ESBL) and carbapenemase-resistant (CR) Enterobacterales in rectal swabs of bats submitted to the Chilean national rabies surveillance program from 2021 to 2022. From the 307 swabs screened, 47 (15%) harboured cefotaxime-resistant Enterobacterales. Bats carrying these bacteria originated from 9 out of the 14 Chilean regions. Most positive samples were obtained from Tadarida brasiliensis (n = 42), but also Lasiurus varius, L. cinereus and Histiotus macrotus. No Enterobacterales were resistant to imipenem. All ESBL-Enterobacterales were confirmed as Rahnella aquatilis by MALDI-TOF. No other ESBL or CR Enterobacterales were detected. To our knowledge, this is the first screening of antibiotic-resistant bacteria in wild bats of Chile, showing the bat faecal carriage of R. aquatilis naturally resistant to cephalosporins, but also including acquired resistance to important antibiotics for public health such as amoxicillin with clavulanic acid. Our results suggest unknown selective pressures on R. aquatilis, but low or no carriage of ESBL or CR Escherichia coli and Klebsiella spp. Future studies should assess the zoonotic and environmental implications of R. aquatilis, which are likely present in the guano left by bats roosting in human infrastructures. © 2023 The Authors.
NEDD4-1 deficiency impairs satellite cell function during skeletal muscle regeneration
(BioMed Central Ltd, 0023-12) Cabezas, Felipe; Cabello-Verrugio, Claudio; González, Natalia; Salas, Jeremy; Ramírez, Manuel J.; de la Vega, Eduardo; Olguín, Hugo C
Background: Satellite cells are tissue-specific stem cells primarily responsible for the regenerative capacity of skeletal muscle. Satellite cell function and maintenance are regulated by extrinsic and intrinsic mechanisms, including the ubiquitin–proteasome system, which is key for maintaining protein homeostasis. In this context, it has been shown that ubiquitin-ligase NEDD4-1 targets the transcription factor PAX7 for proteasome-dependent degradation, promoting muscle differentiation in vitro. Nonetheless, whether NEDD4-1 is required for satellite cell function in regenerating muscle remains to be determined. Results: Using conditional gene ablation, we show that NEDD4-1 loss, specifically in the satellite cell population, impairs muscle regeneration resulting in a significant reduction of whole-muscle size. At the cellular level, NEDD4-1-null muscle progenitors exhibit a significant decrease in the ability to proliferate and differentiate, contributing to the formation of myofibers with reduced diameter. Conclusions: These results indicate that NEDD4-1 expression is critical for proper muscle regeneration in vivo and suggest that it may control satellite cell function at multiple levels. © 2023, The Author(s).
Removal of a partial genomic duplication restores synaptic transmission and behavior in the MyosinVA mutant mouse Flaile
(BioMed Central Ltd, 0023-12) Bustos, Fernando J.; Pandian, Swarna; Haensgen, Henny; Zhao, Jian-Ping; Strouf, Haley; Heidenreich, Matthias; Swiech, Lukasz; Deverman, Benjamin E.; Gradinaru, Viviana; Zhang, Feng; Constantine-Paton, Martha
Background: Copy number variations, and particularly duplications of genomic regions, have been strongly associated with various neurodegenerative conditions including autism spectrum disorder (ASD). These genetic variations have been found to have a significant impact on brain development and function, which can lead to the emergence of neurological and behavioral symptoms. Developing strategies to target these genomic duplications has been challenging, as the presence of endogenous copies of the duplicate genes often complicates the editing strategies. Results: Using the ASD and anxiety mouse model Flailer, which contains a partial genomic duplication working as a dominant negative for MyoVa, we demonstrate the use of DN-CRISPRs to remove a 700 bp genomic region in vitro and in vivo. Importantly, DN-CRISPRs have not been used to remove genomic regions using sgRNA with an offset greater than 300 bp. We found that editing the flailer gene in primary cortical neurons reverts synaptic transport and transmission defects. Moreover, long-term depression (LTD), disrupted in Flailer animals, is recovered after gene editing. Delivery of DN-CRISPRs in vivo shows that local delivery to the ventral hippocampus can rescue some of the mutant behaviors, while intracerebroventricular delivery, completely recovers the Flailer animal phenotype associated to anxiety and ASD. Conclusions: Our results demonstrate the potential of DN-CRISPR to efficiently remove larger genomic duplications, working as a new gene therapy approach for treating neurodegenerative diseases. © 2023, BioMed Central Ltd., part of Springer Nature.
Reduced microbial diversity of the nasopharyngeal microbiome in household contacts with latent tuberculosis infection
(Nature Research, 0023-12) Ruiz-Tagle, Cinthya; Ugalde, Juan A.; Naves, Rodrigo; Araos, Rafael; García, Patricia f; Balcells, María Elvira
The upper respiratory tract is an obliged pathway for respiratory pathogens and a healthy microbiota may support the host's mucosal immunity preventing infection. We analyzed the nasopharyngeal microbiome in tuberculosis household contacts (HHCs) and its association with latent tuberculosis infection (TBI). A prospective cohort of HHCs was established and latent TBI status was assessed by serial interferon-γ release assay (IGRA). Nasopharyngeal swabs collected at baseline were processed for 16S rRNA gene sequencing. The 82 participants included in the analysis were classified as: (a) non-TBI [IGRA negative at baseline and follow-up, no active TB (n = 31)], (b) pre-TBI [IGRA negative at baseline but converted to IGRA positive or developed active TB at follow-up (n = 16)], and (c) TBI [IGRA positive at enrollment (n = 35)]. Predominant phyla were Actinobacteriota, Proteobacteria, Firmicutes and Bacteroidota. TBI group had a lower alpha diversity compared to non-TBI (padj = 0.04) and pre-TBI (padj = 0.04). Only TBI and non-TBI had beta diversity differences (padj = 0.035). Core microbiomes’ had unique genera, and genus showed differential abundance among groups. HHCs with established latent TBI showed reduced nasopharyngeal microbial diversity with distinctive taxonomical composition. Whether a pre-existing microbiome feature favors, are a consequence, or protects against Mycobacterium tuberculosis needs further investigation. © 2023, The Author(s).
Ursodeoxycholic acid induces sarcopenia associated with decreased protein synthesis and autophagic flux
(BioMed Central Ltd, 0023-12) Orozco-Aguilar, Josué; Tacchi, Franco; Aguirre, Francisco; Valero-Breton, Mayalen; Castro-Sepulveda, Mauricio; Simon, Felipe; Cabello-Verrugio, Claudio
Background: Skeletal muscle generates force and movements and maintains posture. Under pathological conditions, muscle fibers suffer an imbalance in protein synthesis/degradation. This event causes muscle mass loss and decreased strength and muscle function, a syndrome known as sarcopenia. Recently, our laboratory described secondary sarcopenia in a chronic cholestatic liver disease (CCLD) mouse model. Interestingly, the administration of ursodeoxycholic acid (UDCA), a hydrophilic bile acid, is an effective therapy for cholestatic hepatic alterations. However, the effect of UDCA on skeletal muscle mass and functionality has never been evaluated, nor the possible involved mechanisms. Methods: We assessed the ability of UDCA to generate sarcopenia in C57BL6 mice and develop a sarcopenic-like phenotype in C2C12 myotubes and isolated muscle fibers. In mice, we measured muscle strength by a grip strength test, muscle mass by bioimpedance and mass for specific muscles, and physical function by a treadmill test. We also detected the fiber’s diameter and content of sarcomeric proteins. In C2C12 myotubes and/or isolated muscle fibers, we determined the diameter and troponin I level to validate the cellular effect. Moreover, to evaluate possible mechanisms, we detected puromycin incorporation, p70S6K, and 4EBP1 to evaluate protein synthesis and ULK1, LC3 I, and II protein levels to determine autophagic flux. The mitophagosome-like structures were detected by transmission electron microscopy. Results: UDCA induced sarcopenia in healthy mice, evidenced by decreased strength, muscle mass, and physical function, with a decline in the fiber’s diameter and the troponin I protein levels. In the C2C12 myotubes, we observed that UDCA caused a reduction in the diameter and content of MHC, troponin I, puromycin incorporation, and phosphorylated forms of p70S6K and 4EBP1. Further, we detected increased levels of phosphorylated ULK1, the LC3II/LC3I ratio, and the number of mitophagosome-like structures. These data suggest that UDCA induces a sarcopenic-like phenotype with decreased protein synthesis and autophagic flux. Conclusions: Our results indicate that UDCA induces sarcopenia in mice and sarcopenic-like features in C2C12 myotubes and/or isolated muscle fibers concomitantly with decreased protein synthesis and alterations in autophagic flux. © 2023, The Author(s).
Ontogenetically distinct neutrophils differ in function and transcriptional profile in zebrafish
(Nature Research, 0023-12) García-López, Juan P.; Grimaldi, Alexandre; Chen, Zelin; Meneses, Claudio; Bravo-Tello, Karina; Bresciani, Erica; Banderas, Alvaro; Burgess, Shawn M.; Hernández, Pedro P; Feijoo, Carmen G
The current view of hematopoiesis considers leukocytes on a continuum with distinct developmental origins, and which exert non-overlapping functions. However, there is less known about the function and phenotype of ontogenetically distinct neutrophil populations. In this work, using a photoconvertible transgenic zebrafish line; Tg(mpx:Dendra2), we selectively label rostral blood island-derived and caudal hematopoietic tissue-derived neutrophils in vivo during steady state or upon injury. By comparing the migratory properties and single-cell expression profiles of both neutrophil populations at steady state we show that rostral neutrophils show higher csf3b expression and migration capacity than caudal neutrophils. Upon injury, both populations share a core transcriptional profile as well as subset-specific transcriptional signatures. Accordingly, both rostral and caudal neutrophils are recruited to the wound independently of their distance to the injury. While rostral neutrophils respond uniformly, caudal neutrophils respond heterogeneously. Collectively, our results reveal that co-existing neutrophils populations with ontogenically distinct origin display functional differences. © 2023, Springer Nature Limited.
Domestic Cat Hepadnavirus and Pathogenic Retroviruses; A Sero-Molecular Survey of Cats in Santiago, Chile
(Multidisciplinary Digital Publishing Institute (MDPI), 0024) Choi, Yan Ru; Iturriaga, María Paz; Nekouei, Omid; Tu, Thomas; Van Brussel, Kate; Barrs, Vanessa R.; Beatty, Julia A.
Cat ownership is common in Chile, but data on the regional prevalence of infectious agents are limited. A sero-molecular survey of 120 client- or shelter-owned domestic cats in greater Santiago was performed. Whole blood DNA was tested for the novel hepatitis-B-like virus, domestic cat hepadnavirus (DCH) by conventional PCR (cPCR) and quantitative PCR (qPCR), and for feline leukaemia virus (FeLV) by qPCR. Point-of-care serology for FeLV p27 antigen and antibodies recognising feline immunodeficiency virus (FIV) p15 and p24 was performed. DCH DNA was detected in the serum of 2/120 cats (1.67%). Sequencing and phylogenetic analysis showed that the DCH detected in Chile occupies a position outside the main clustering of DCH in the near-complete genome tree. Progressive (antigen-positive, provirus-positive) and regressive (antigen-negative, provirus-positive) FeLV infections were identified in 6/120 (5%) and 9/120 (7.5%) of cats. A total of 2/120 (1.7%) cats had dual FeLV/FIV infection, and another 2 cats had FIV infection alone. This study shows that the global footprint of DCH includes South America with a low molecular frequency in Chile, similar to that reported in the USA. Progressive FeLV infection is relatively common in urban Chile, and male cats are at greater risk than females. Testing and control measures for pathogenic retroviruses are indicated. The potential impact of FeLV, FIV and DCH on Chile’s wildcat species is worthy of further investigation. © 2023 by the authors.
Transient gestational hypothyroxinemia accelerates and enhances ulcerative colitis-like disorder in the male offspring
(Frontiers Media SA, 0024) Rivera, Juan Carlos; Opazo, Ma. Cecilia; Hernández-Armengol, Rosario; Álvarez, Oscar; Mendoza-León, María José; Caamaño, Esteban; Gatica, Sebastian; Bohmwald, Karen; Bueno, Susan M.; González, Pablo A.; Neunlist, Michel; Boudin, Helene
Introduction: Gestational hypothyroxinemia (HTX) is a condition that occurs frequently at the beginning of pregnancy, and it correlates with cognitive impairment, autism, and attentional deficit in the offspring. Evidence in animal models suggests that gestational HTX can increase the susceptibility of the offspring to develop strong inflammation in immune-mediated inflammatory diseases. Ulcerative colitis (UC) is a frequent inflammatory bowel disease with unknown causes. Therefore, the intensity of ulcerative colitis-like disorder (UCLD) and the cellular and molecular factors involved in proinflammatory or anti-inflammatory responses were analyzed in the offspring gestated in HTX (HTX-offspring) and compared with the offspring gestated in euthyroidism (Control-offspring). Methods: Gestational HTX was induced by the administration of 2-mercapto-1-methylimidazole in drinking water to pregnant mice during E10–E14. The HTX-offspring were induced with UCLD by the acute administration of dextran sodium sulfate (DSS). The score of UCLD symptomatology was registered every day, and colon histopathology, immune cells, and molecular factors involved in the inflammatory or anti-inflammatory response were analyzed on day 6 of DSS treatment. Results: The HTX-offspring displayed earlier UCLD pathological symptoms compared with the Control-offspring. After 6 days of DSS treatment, the HTX-offspring almost doubled the score of the Control-offspring. The histopathological analyses of the colon samples showed signs of inflammation at the distal and medial colon for both the HTX-offspring and Control-offspring. However, significantly more inflammatory features were detected in the proximal colon of the HTX-offspring induced with UCLD compared with the Control-offspring induced with UCLD. Significantly reduced mRNA contents encoding for protective molecules like glutamate-cysteine ligase catalytic subunit (GCLC) and mucin-2 (MUC-2) were found in the colon of the HTX-offspring as compared with the Control-offspring. Higher percentages of Th17 lymphocytes were detected in the colon tissues of the HTX-offspring induced or not with UCLD as compared with the Control-offspring. Discussion: Gestational HTX accelerates the onset and increases the intensity of UCLD in the offspring. The low expression of MUC-2 and GCLC together with high levels of Th17 Lymphocytes in the colon tissue suggests that the HTX-offspring has molecular and cellular features that favor inflammation and tissue damage. These results are important evidence to be aware of the impact of gestational HTX as a risk factor for UCLD development in offspring. Copyright © 2024 Rivera, Opazo, Hernández-Armengol, Álvarez, Mendoza-León, Caamaño, Gatica, Bohmwald, Bueno, González, Neunlist, Boudin, Kalergis and Riedel.
Impact of KDM6B mosaic brain knockout on synaptic function and behavior
(10.1038/s41598-024-70728-5, 0024-12) Brauer, Bastian; Ancatén-González, Carlos; Ahumada-Marchant, Constanza; Meza, Rodrigo C.; Merino-Veliz, Nicolas; Nardocci, Gino; Varela-Nallar, Lorena; Arriagada, Gloria; Chávez, Andrés E.; Bustos, Fernando J.
Autism spectrum disorders (ASD) are complex neurodevelopmental conditions characterized by impairments in social communication, repetitive behaviors, and restricted interests. Epigenetic modifications serve as critical regulators of gene expression playing a crucial role in controlling brain function and behavior. Lysine (K)-specific demethylase 6B (KDM6B), a stress-inducible H3K27me3 demethylase, has emerged as one of the highest ASD risk genes, but the precise effects of KDM6B mutations on neuronal activity and behavioral function remain elusive. Here we show the impact of KDM6B mosaic brain knockout on the manifestation of different autistic-like phenotypes including repetitive behaviors, social interaction, and significant cognitive deficits. Moreover, KDM6B mosaic knockout display abnormalities in hippocampal excitatory synaptic transmission decreasing NMDA receptor mediated synaptic transmission and plasticity. Understanding the intricate interplay between epigenetic modifications and neuronal function may provide novel insights into the pathophysiology of ASD and potentially inform the development of targeted therapeutic interventions. © The Author(s) 2024.
Global transcriptome profiles provide insights into muscle cell development and differentiation on microstructured marine biopolymer scaffolds for cultured meat production
(Nature Research, 0024-12) Bezjak, Dragica; Orellana, Nicole; Valdivia, Guillermo; Acevedo, Cristian A.; Valdes, Jorge H.
Biomaterial scaffolds play a pivotal role in the advancement of cultured meat technology, facilitating essential processes like cell attachment, growth, specialization, and alignment. Currently, there exists limited knowledge concerning the creation of consumable scaffolds tailored for cultured meat applications. This investigation aimed to produce edible scaffolds featuring both smooth and patterned surfaces, utilizing biomaterials such as salmon gelatin, alginate, agarose and glycerol, pertinent to cultured meat and adhering to food safety protocols. The primary objective of this research was to uncover variations in transcriptomes profiles between flat and microstructured edible scaffolds fabricated from marine-derived biopolymers, leveraging high-throughput sequencing techniques. Expression analysis revealed noteworthy disparities in transcriptome profiles when comparing the flat and microstructured scaffold configurations against a control condition. Employing gene functional enrichment analysis for the microstructured versus flat scaffold conditions yielded substantial enrichment ratios, highlighting pertinent gene modules linked to the development of skeletal muscle. Notable functional aspects included filament sliding, muscle contraction, and the organization of sarcomeres. By shedding light on these intricate processes, this study offers insights into the fundamental mechanisms underpinning the generation of muscle-specific cultured meat. © The Author(s) 2024.
A Deep Dive into the Trophic Ecology of Engraulis ringens: Assessing Diet Through Stomach Content and Stable Isotope Analysis
(Multidisciplinary Digital Publishing Institute (MDPI), 0024-12) Cárcamo, Carolina; Schultz, Eric T.; Leiva, Francisco; Saavedra, Alvaro; Klarian, Sebastian A.
Our study investigates the trophic ecology of the anchoveta (Engraulis ringens). The anchoveta plays a key role in the Greater Humboldt Ecosystem and is extensively exploited by countries from the south-eastern Pacific Ocean. For a comprehensive study of trophic ecology, we employed a combined approach that included stomach content analysis, stable isotope analysis, and scaled mass index of body condition. Our results showed that the multivariate composition of the diet varies significantly between life stage and fishing zones in Chile. Copepods and euphausiids emerged as the dominant prey found in the stomachs across all fisheries zones. Stable isotope analysis revealed significant differences among different zones. The scaled mass index values were higher in the northern zone compared to the southern zones, for both juveniles and adults. This research carries significant implications for fisheries management and conservation efforts, such as the development of targeted management strategies that address variations in the trophic structure of anchoveta across different life stages and fishing zones. © 2024 by the authors.
Unrolling the Systematics of a Southeastern Pacific Chiton
(Multidisciplinary Digital Publishing Institute (MDPI), 0024-12) Ibáñez, Christian M.; Sirenko, Boris
The species Chiton echinatus was first described by Barmes in 1824. Subsequently, it has been allocated to several widely distributed genera (e.g., Acanthopleura, Enoplochiton, Mesotomura) within the subfamily Acanthopleurinae. In order to resolve this species’ taxonomic uncertainty, specimens were collected throughout its entire distribution (i.e. from Peru and Chile) and subjected to a series of morphological and phylogenetic analyses. Scanning electron microscopy was used to improve this species’ morphological description, whereas publicly available sequences were used to infer its phylogenetic position. Morphological and phylogenetic analyses suggest that this species merits its own genus, endemic to the Southeastern Pacific. Of the aforementioned genera, Mesotomura appears to be the most appropriate designation. Therefore, it is proposed that the name Mesotomura echinata be restored, and the range of this species be extended to 39° S. © 2024 by the authors.
Large-scale molecular survey for piroplasmids in Iberian wild carnivores
(Springer Science and Business Media Deutschland GmbH, 0024-12-13) Millán, Javier; Checa, Rocío; Oleaga, Álvaro; Rodríguez, Alejandro; Negre, Nieves; Llaneza, Luis; Velarde, Roser; Miró, Guadalupe
Piroplasmids are vector-borne hemoprotozoan parasites belonging to the phylum Apicomplexa that are of veterinary and medical importance. Wild carnivores are hosts for diverse piroplasmids, some of which are highly pathogenic for domestic dogs and cats. A large-scale survey including samples from 244 individuals belonging to eleven different species that were opportunistically obtained between 1993 and 2015 in four Autonomous Regions in Spain were tested for piroplasmid DNA with two different nested-PCR assays targeting the 18S rRNA gene. Sixty of 85 Eurasian badgers (Meles meles), 11 of 42 red foxes (Vulpes vulpes), and 1 of 10 stone martens (Martes foina) resulted positive. In contrast, 46 wolves (Canis lupus), 26 genets (Genetta genetta), 22 pine martens (Martes martes), and other less-represented species were negative. Sequencing revealed that all foxes and one badger were parasitized by Babesia vulpes, and the remaining badgers and the stone marten by Babesia sp. badger type A (BBTA). The prevalence of BBTA in Catalonian badgers was significantly lower in Alpine than in Continental and Mediterranean climates. This study confirms that badgers and ref foxes constitute the natural hosts of BBTA and B. vulpes, respectively, with occasional spillovers to other species. © The Author(s) 2024.
Hydatigera parva population genetics in Iberian rodents provides insights into its introduction from Africa
(Cambridge University Press, 0025) Miljević, Milan; Rajičić, Marija; Marco, Javier; Blagojević, Jelena; Rodríguez-Pastor, Ruth; Bajić, Branka; Millán, Javier
This study investigated the prevalence and genetic diversity of Hydatigera parva in 341 native rodents in a riparian habitat in the Mediterranean part of Spain. Polycephalic larvae were found in 32% of wood mice (Apodemus sylvaticus; n=84) and 0.4% of Algerian mice (Mus spretus; n=257) examined, with a significantly higher prevalence in the former. No significant differences in infection prevalence in wood mouse were found between sex and age groups, habitats (agricultural vs natural), or seasons. Genetic analysis of 25 cysts using cox1 sequences revealed low nucleotide (0.00110) and haplotype diversity (0.380), suggesting limited genetic variation. Phylogenetic analysis showed that the studied H. parva isolates were genetically distinct from other species within the genus Hydatigera. The results support the hypothesis that H. parva was introduced to Europe from Africa, possibly with its final host, the common genet (Genetta genetta), an abundant predator in the study area, and suggest a lower genetic diversity in Europe than in African populations. This study is the first population genetic study of H. parva in the Iberian Peninsula. It provides insights into the population structure of the parasite and its interaction with rodent hosts, and thereby constitutes an example of the potential identification of an introduction route of a parasite with its definitive host. It also confirms the importance of the wood mouse as an intermediate host for the maintenance of the parasite's life cycle in Europe and forms the basis for further studies on the distribution and genetic diversity of H. parva. © The Author(s), 2025.
Production of minicell-like structures by Escherichia coli biosynthesizing cadmium fluorescent nanoparticles: a novel response to heavy metal exposure
(BioMed Central Ltd, 0025) Valenzuela-Ibaceta, Felipe; Álvarez, Sergio A.; Pérez-Donoso, José M.
The bacterial synthesis of fluorescent semiconductor nanoparticles or quantum dots (QDs), presents a sustainable method for producing nanomaterials with customized optical properties and significant technological potential. However, the underlying cellular mechanisms for this process remain elusive. Specifically, the role of cellular structures in QD generation has not been thoroughly investigated. In this study, we examined the morphological changes in Escherichia coli during the biosynthesis of cadmium sulfide (CdS) QDs, using a strain overexpressing the gshA gene to promote QD biosynthesis through increased glutathione (GSH) levels. Microscopy analyses revealed that fluorescence emission associated with QDs was concentrated at the cell poles, along with fluorescence emission from small spherical cells, a phenomenon exclusively detectable during QD biosynthesis. Transmission electron microscopy (TEM) revealed electron-dense nanomaterials localized at the cell poles. Furthermore, it was demonstrated the formation of minicell-like structures (∼ 0.5 μm in diameter) originating from these poles under biosynthesis conditions. These minicells encapsulated nanometric electron-dense material. Additional analyses indicated that minicells contained inclusion bodies, likely formed due to gshA overexpression and cadmium stress. Our findings confirms the role of minicells as a bacterial mechanism for sequestering cadmium at the cell poles and expelling the metal in the form of nanoparticles. This underscores the importance of minicells in bacterial physiology and stress responses, introducing a novel mechanism for heavy metal detoxification in bacteria. © The Author(s) 2025.
Polyplacophoran Assemblages in Shallow Waters of the West Antarctic Peninsula: Patterns of Diversity, Composition and Abundance
(Multidisciplinary Digital Publishing Institute (MDPI), 0025) Ibáñez, Christian M.; Rosenfeld, Sebastián; Catalán, Jennifer; Zapata-Hernández, Germán; Gacitúa-Leible, Manuel; Vargas, Rocio; Morales, Pamela; Díaz, Angie; Carrasco, Sergio A; Sellanes, Javier; Mills, Sadie
For the first time, field surveys for exploring the diversity and composition of shallow-water polyplacophorans in West Antarctica have been conducted. During the austral summer sampling campaigns of 2022, 2023 and 2024, a total of 1717 specimens of four species were collected from 21 localities. The composition, abundance, and diversity estimate of the assemblages showed that richness decreased southward due to changes in species composition. The ordination analysis showed a high similarity among localities. Thus, of the seven shallow-water chiton species previously recorded in Antarctica, only four were recorded here. Of them, Tonicina zschaui, Leptochiton kerguelensis, and Hemiarthrum setulosum were the most common and abundant, while Callochiton bouveti was the rarest and least abundant species. The diversity of shallow-water polyplacophorans in this area of Antarctica is low compared to the higher number of species reported in other sub-Antarctic regions. It is suggested that the effect of ice cover on shallow-water habitats could affect the abundance and diversity of chitons. In turn, the high similarity of assemblages may be due to the transport of larvae and juveniles by ocean currents and rafting between the studied sites. © 2025 by the authors.
Ventilation-induced acute kidney injury in acute respiratory failure: Do PEEP levels matter?
(BioMed Central Ltd, 0025) Benites, Martín H.; Suarez-Sipmann, Fernando; Kattan, Eduardo; Cruces, Pablo; Retamal, Jaime
Acute Respiratory Distress Syndrome (ARDS) is a leading cause of morbidity and mortality among critically ill patients, and mechanical ventilation (MV) plays a critical role in its management. One of the key parameters of MV is the level of positive end-expiratory pressure (PEEP), which helps to maintain an adequate lung functional volume. However, the optimal level of PEEP remains controversial. The classical approach in clinical trials for identifying the optimal PEEP has been to compare “high” and “low” levels in a dichotomous manner. High PEEP can improve lung compliance and significantly enhance oxygenation but has been inconclusive in hard clinical outcomes such as mortality and duration of MV. This discrepancy could be related to the fact that inappropriately high or low PEEP levels may adversely affect other organs, such as the heart, brain, and kidneys, which could counteract its potential beneficial effects on the lung. Patients with ARDS often develop acute kidney injury, which is an independent marker of mortality. Three primary mechanisms have been proposed to explain lung-kidney crosstalk during MV: gas exchange abnormalities, such as hypoxemia and hypercapnia; remote biotrauma; and hemodynamic changes, including reduced venous return and cardiac output. As PEEP levels increase, lung volume expands to a variable extent depending on mechanical response. This dynamic underlies two potential mechanisms that could impair venous return, potentially leading to splanchnic and renal congestion. First, increasing PEEP may enhance lung aeration, particularly in highly recruitable lungs, where previously collapsed alveoli reopen, increasing lung volume and pleural pressure, leading to vena cava compression, which can contribute to systemic venous congestion and abdominal organ impairment function. Second, in lungs with low recruitability, PEEP elevation may induce minimal changes in lung volume while increasing airway pressure, resulting in alveolar overdistension, vascular compression, and increased pulmonary vascular resistance. Therefore, we propose that high PEEP settings can contribute to renal congestion, potentially impairing renal function. This review underscores the need for further rigorous research to validate these perspectives and explore strategies for optimizing PEEP settings while minimizing adverse renal effects. © The Author(s) 2025.
Tracing the invasion: Wing morphometrics reveal population spread and adaptation patterns of Halyomorpha halys (Stål, 1855) across Southern Europe
(Public Library of Science, 0025) Pajač Beus, Martina a; Lemic, Darija; Benítez, Hugo A. b; Pérez, Laura M; Rot, Mojca; Konjević, Aleksandra; Andreadis, Stefanos S.; Živković, Ivana Pajač
Invasive species such as Halyomorpha halys (Stål, 1855), the brown marmorated stink bug, pose a significant threat to agriculture due to their rapid spread and adaptability. The aim of this study is to assess the phenotypic variability of H. halys populations by analyzing the size and shape morphology of the anterior and posterior wings and to determine whether geometric morphometrics can serve as a cost-effective alternative to genetic methods for tracking invasion patterns. Populations from four southern European countries (Croatia, Serbia, Slovenia and Greece) with 540 specimens and 2,160 wings were analysed and showed clear phenotypic differences in wing morphology consistent with the known invasion dynamics previously determined by genetic studies. Mahalanobis distances highlight the close morphological relationship between the Serbian and Slovenian populations, suggesting common ancestry or recent gene flow, while the Greek and Croatian populations show significant differences, suggesting different invasion pathways or rapid morphological adaptation. The Greek population exhibited lower phenotypic plasticity, whereas the Serbian population displayed the greatest variation, likely reflecting the influence of multiple invasion sources. These results show that wing morphology can reliably detect invasion-related patterns and phenotypic plasticity and is a valuable tool for biomonitoring in integrated pest management programs, especially in areas where genetic methods are less feasible. This study highlights the utility of geometric morphometrics in monitoring the spread and adaptation of invasive species such as H. halys in different environments. © 2025 Pajač Beus et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Production of minicell-like structures by Escherichia coli biosynthesizing cadmium fluorescent nanoparticles: a novel response to heavy metal exposure
(BioMed Central Ltd, 0025) Valenzuela-Ibaceta, Felipe; Álvarez, Sergio A.; Pérez-Donoso, José M.
The bacterial synthesis of fluorescent semiconductor nanoparticles or quantum dots (QDs), presents a sustainable method for producing nanomaterials with customized optical properties and significant technological potential. However, the underlying cellular mechanisms for this process remain elusive. Specifically, the role of cellular structures in QD generation has not been thoroughly investigated. In this study, we examined the morphological changes in Escherichia coli during the biosynthesis of cadmium sulfide (CdS) QDs, using a strain overexpressing the gshA gene to promote QD biosynthesis through increased glutathione (GSH) levels. Microscopy analyses revealed that fluorescence emission associated with QDs was concentrated at the cell poles, along with fluorescence emission from small spherical cells, a phenomenon exclusively detectable during QD biosynthesis. Transmission electron microscopy (TEM) revealed electron-dense nanomaterials localized at the cell poles. Furthermore, it was demonstrated the formation of minicell-like structures (∼ 0.5 μm in diameter) originating from these poles under biosynthesis conditions. These minicells encapsulated nanometric electron-dense material. Additional analyses indicated that minicells contained inclusion bodies, likely formed due to gshA overexpression and cadmium stress. Our findings confirms the role of minicells as a bacterial mechanism for sequestering cadmium at the cell poles and expelling the metal in the form of nanoparticles. This underscores the importance of minicells in bacterial physiology and stress responses, introducing a novel mechanism for heavy metal detoxification in bacteria. © The Author(s) 2025.
Connexin46 in the nucleus of cancer cells: a possible role as transcription modulator
(10.1186/s12964-025-02151-w, 0025) Fernández-Olivares, Ainoa; Orellana, Viviana P; Llanquinao, Jesús; Nuñez, Gonzalo; Pérez-Moreno, Pablo; Contreras-Riquelme, Sebastián; Martin, Alberto JM; Mammano, Fabio; Alfaro, Ivan E; Calderón, Juan F; Stehberg, Jimmy; Sáez, Mauricio A
Background: Oncogenes drive cancer progression, but few are active exclusively in tumor cells. Connexins (Cxs), traditionally recognized as ion channel proteins, can localize to the nucleus and regulate gene expression, playing key roles in both physiological and pathological processes. Cx46, once thought to be restricted to the eye lens, has been implicated in tumor growth, though its underlying mechanisms remain unclear. This study investigates the nuclear presence of Cx46 in cancer cells and its potential role as a transcriptional modulator. Methods: We employed ChIP-Seq, confocal immunofluorescence, and nuclear protein purification to assess Cx46 localization and DNA interactions. Functional assays were conducted to evaluate its effects on invasion, division, spheroid formation, and mesenchymal marker expression. Single-point mutations and molecular dynamics simulations were used to explore potential Cx46-DNA interactions. Results: Cx46 mRNA upregulation was found in a variety of tumors compared to adjacent healthy tissue. In HeLa cells, which do not express Cx46, its transfection promoted proliferation, invasion and self-renewal capacity, cancer stem cell traits and mesenchymal features. Consistently, in Sk-Mel-2, which naturally express Cx46, reduced Cx46 expression led to a decrease in the similar parameters. In HeLa cells, nuclear Cx46 was detected in two forms, full length 46 kDa and a 30 kDa fragment (GJA3-30 k), ChIP-Seq experiments revealed that Cx46 binds to the DNA at intergenic and promoter regions, leading to the activation of oncogenic pathways. Molecular dynamics simulations suggest that GJA3-30 k dimerizes in a RAD50-like structure, forming stable DNA complexes. Cx46 and in some cases GJA3-30 k were detected in the nuclei of multiple cancer cell lines, including prostate, breast and skin cancers. Conclusions: Our findings reveal a novel nuclear role for Cx46 in cancer, demonstrating its function as a transcriptional regulator and its potential as a therapeutic target. © The Author(s) 2025.

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