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Papers by Carlos Smith

Research paper thumbnail of Reducción de selenito a Selenio elemental por Pantoea agglomerans

Gayana, Jun 1, 2016

El selenio es esencial y requerido por distintos sistemas biológicos para su crecimiento y metabo... more El selenio es esencial y requerido por distintos sistemas biológicos para su crecimiento y metabolismo. Su transformación en el ambiente ocurre principalmente por microorganismos que reducen el selenito a selenio elemental. Pantoea agglomerans UC-32 reduce el selenito a nanopartículas de selenio elemental. El objetivo de este trabajo fue determinar la cinética de reducción de selenito a selenio elemental y la ubicación celular de la actividad reductora en Pantoea agglomerans UC-32. Se ensayó la actividad reductora de P. agglomerans frente a diferentes concentraciones de selenito, evaluándose la disminución de selenito y aparición de selenio elemental. La ubicación de la actividad reductora fue estudiada por fraccionamiento celular y zimograma. Al ensayar la actividad reductora de selenito se encontró que la enzima se satura a concentraciones bajas de este compuesto y el zimograma localizó esta actividad en la fracción citoplasmática y que requiere NADPH como coenzima. En conclusión, P. agglomerans es capaz de reducir selenito a selenio elemental insoluble inmovilizado en la biomasa en condiciones aeróbicas y que la enzima que cataliza esta reducción se localiza en la fracción de citoplasmática. Estas características permitirían la "síntesis verde" de nanopartículas de selenio las cuales tienen aplicación en la biorremediación de diferentes matrices, como suelo o agua contaminadas.

Research paper thumbnail of In vitro effect of Levamisole on Rainbow Trout (Oncorhynchus mykiss) peripheral blood mononuclear cells

Gayana (Concepción), 2015

In vitro effect of Levamisole on Rainbow Trout (Oncorhynchus mykiss) peripheral blood mononuclear... more In vitro effect of Levamisole on Rainbow Trout (Oncorhynchus mykiss) peripheral blood mononuclear cells Efecto in vitro del levamisol sobre las celulas mononucleares de la sangre periférica de trucha arcoíris (Oncorhynchus mykiss

Research paper thumbnail of In vitro cytotoxic capacity against tumor cell lines and antioxidant activity of acidic polysaccharides isolated from the Andean Patagonian fungus Phylloporia boldo

Natural Product Research

Fungal polysaccharides possess a broad biological activity, including cytotoxic and antioxidant a... more Fungal polysaccharides possess a broad biological activity, including cytotoxic and antioxidant activities. This work aimed to evaluate the cytotoxic and antioxidant activity of the acidic polysaccharides of Phylloporia boldo strain (named PBAP40). Cytotoxic activity of polysaccharide was evaluated determining the viability of three tumor cell lines by MTT assay. The effect of acidic polysaccharide on the cell cycle of HL-60 cell line was evaluated by flow cytometry, and the antioxidant activity was determined by DPPH and ABTS assays. PBAP40 showed cytotoxic effects in tumor cell lines. Results suggest that P. boldo acidic polysaccharides arrested tumor cells in the cell cycle Sub G1 phase. The acidic polysaccharides of PBAP40 strain were not cytotoxic for the non-tumor cell line. PBAP40 also showed excellent antioxidant activity. The FT-IR analysis of the acidic polysaccharides indicated the presence of glucans bearing α-and β-type glycosidic bonds.

Research paper thumbnail of EVALUATION OF CYTOTOXIC EFFECT AGAINST TUMOUR CELLS OF THE ACIDIC POLYSACCHARIDES OF THE FUNGUS Nothophellinus andinopatagonicus

Journal of the Chilean Chemical Society

Fungal polysaccharides possess an important bioactive potential, including antioxidant and antica... more Fungal polysaccharides possess an important bioactive potential, including antioxidant and anticarcinogenic activity. The aim of this work was to determine the antioxidant activity and cytotoxicity against tumour and non-tumour cell lines acidic polysaccharides (NAAPs) of the fungus Nothophellinus andinopatagonicus. The effect of NAAPs on tumour cells lines was evaluated by MTT assay and flow cytometry. The analyses determined that glucose was the most abundant monomer and IR spectrum showed the typical peaks of β-glucans in the NAAPs. The cell viability assays revealed significant activity of NAAPs against HL-60, HCT-116 and MCF-7 tumour cell lines (IC50 = 767,16 µg mL-1 , 1256 µg mL-1 and 4241,7 µg mL-1 , respectively); but a much lower cytotoxicity against the non-tumour cell line HGF-1 (outside the range of the highest concentration tested (>10 mg mL-1)). NAAPs affected the cell cycle of HL-60 tumour cells, increasing the percentage of cells in the sub G1 phase and reducing it in the S/G2/M phases. Moreover, low concentrations of NAAPs also showed an effective cytotoxic activity against tumour cell lines while the non-tumour cell line was unaffected, maintaining a viability close to 100%. The antioxidant activity of the highest NAAPs concentration tested was 6.24% and 4.63%, for DPPH and ABTS method, respectively.

Research paper thumbnail of Can Probiotics, Particularly Limosilactobacillus fermentum UCO-979C and Lacticaseibacillus rhamnosus UCO-25A, Be Preventive Alternatives against SARS-CoV-2?

Biology

COVID-19, an infection produced by the SARS-CoV-2 virus in humans, has rapidly spread to become a... more COVID-19, an infection produced by the SARS-CoV-2 virus in humans, has rapidly spread to become a high-mortality pandemic. SARS-CoV-2 is a single-stranded RNA virus characterized by infecting epithelial cells of the intestine and lungs, binding to the ACE2 receptor present on epithelial cells. COVID-19 treatment is based on antivirals and antibiotics against symptomatology in addition to a successful preventive strategy based on vaccination. At this point, several variants of the virus have emerged, altering the effectiveness of treatments and thereby attracting attention to several alternative therapies, including immunobiotics, to cope with the problem. This review, based on articles, patents, and an in silico analysis, aims to address our present knowledge of the COVID-19 disease, its symptomatology, and the possible beneficial effects for patients if probiotics with the characteristics of immunobiotics are used to confront this disease. Moreover, two probiotic strains, L. fermen...

Research paper thumbnail of Selenium Nanoparticle-Enriched and Potential Probiotic, Lactiplantibacillus plantarum S14 Strain, a Diet Supplement Beneficial for Rainbow Trout

Biology

Lactic acid bacteria (LAB), obtained from rainbow trout (Oncorhynchus mykiss) intestine, were cul... more Lactic acid bacteria (LAB), obtained from rainbow trout (Oncorhynchus mykiss) intestine, were cultured in MRS medium and probiotic candidates. Concurrently, producers of elemental selenium nanoparticles (Se0Nps) were selected. Probiotic candidates were subjected to morphological characterization and the following tests: antibacterial activity, antibiotic susceptibility, hemolytic activity, catalase, hydrophobicity, viability at low pH, and tolerance to bile salts. Two LAB strains (S4 and S14) satisfied the characteristics of potential probiotics, but only strain S14 reduced selenite to biosynthesize Se0Nps. S14 strain was identified, by 16S rDNA analysis, as Lactiplantibacillus plantarum. Electron microscopy showed Se0Nps on the surface of S14 cells. Rainbow trout diet was supplemented (108 CFU g−1 feed) with Se0Nps-enriched L. plantarum S14 (LABS14-Se0Nps) or L. plantarum S14 alone (LABS14) for 30 days. At days 0, 15, and 30, samples (blood, liver, and dorsal muscle) were obtained ...

Research paper thumbnail of Consumption of a Gelatin Supplemented with the Probiotic Strain Limosilactobacillus fermentum UCO-979C Prevents Helicobacter pylori Infection in a Young Adult Population Achieved

Foods

Helicobacter pylori is a bacterium associated with various gastrointestinal diseases of high worl... more Helicobacter pylori is a bacterium associated with various gastrointestinal diseases of high worldwide prevalence. Since probiotics are an emerging alternative to managing infection by this pathogenic bacterium, the present work evaluated, in a randomized double-blind study controlled by a placebo, if consuming Limosilactobacillus fermentum UCO-979C prevents H. pylori infection in humans. Participants consumed either L. fermentum UCO-979C-supplemented gelatin (67 participants) or placebo-supplemented gelatin (64 participants) once a day, five days per week for 12 weeks. H. pylori infection in the participants was controlled before and after the intervention detecting H. pylori antigens in stools. Regarding H. pylori-infected participants before the study, 100% remained infected at the end of the study in the placebo group, while 96.7% of those receiving the probiotic remained infected after the intervention. Most importantly, of the non-infected participants, 34.2% became infected a...

Research paper thumbnail of Nutrient Deficiency Promotes the Entry of Helicobacter pylori Cells into Candida Yeast Cells

Biology

Helicobacter pylori, a Gram-negative bacterium, has as a natural niche the human gastric epitheli... more Helicobacter pylori, a Gram-negative bacterium, has as a natural niche the human gastric epithelium. This pathogen has been reported to enter into Candida yeast cells; however, factors triggering this endosymbiotic relationship remain unknown. The aim of this work was to evaluate in vitro if variations in nutrient concentration in the cultured medium trigger the internalization of H. pylori within Candida cells. We used H. pylori–Candida co-cultures in Brucella broth supplemented with 1%, 5% or 20% fetal bovine serum or in saline solution. Intra-yeast bacteria-like bodies (BLBs) were observed using optical microscopy, while intra-yeast BLBs were identified as H. pylori using FISH and PCR techniques. Intra-yeast H. pylori (BLBs) viability was confirmed using the LIVE/DEAD BacLight Bacterial Viability kit. Intra-yeast H. pylori was present in all combinations of bacteria–yeast strains co-cultured. However, the percentages of yeast cells harboring bacteria (Y-BLBs) varied according to ...

Research paper thumbnail of Selenium Nanoparticles Biosynthesized by Pantoea agglomerans and Their Effects on Cellular and Physiological Parameters in the Rainbow Trout Oncorhynchus mykiss

Biology, 2022

The applications of nanoparticles (Nps) as food additives, health enhancers, and antimicrobials i... more The applications of nanoparticles (Nps) as food additives, health enhancers, and antimicrobials in animal production are increasing. The aim of this study was to evaluate the effect of selenium (Se) nanoparticles (Se0Nps) stabilized with L-cysteine (Se0Nps/L-Cys), as a nutritional supplement, on immunological, oxidative status, and productive parameters in O. mykiss. TEM and SEM-EDS showed the accumulation of spherical Se0Nps entirely composed by elemental selenium (Se0) as intracellular and extracellular deposits in Pantoea agglomerans UC-32 strain. The in vitro antioxidant capacity of Se0Nps/L-Cys was significant more efficient ROS scavengers than Se0Nps and Na2SeO3. We also evaluate the effect of Se0Nps/L-Cys on cell viability and oxidative stress in RTgill-W1, RTS-11, or T-PHKM Oncorhynchus mykiss cell lines. Se0Nps/L-Cys showed less toxic and high antioxidant activity than Se0Nps and Na2SeO3. Finally, the dietary Se0Nps/L-Cys had a significant better effect on both plasma lysoz...

Research paper thumbnail of Gastrointestinal Microbiota and Parasite-Fauna of Wild Dissostichus eleginoides Smitt, 1898 Captured at the South-Central Coast of Chile

Microorganisms, 2021

Dissotichus eleginoides has a discontinuous circumpolar geographic distribution restricted to mou... more Dissotichus eleginoides has a discontinuous circumpolar geographic distribution restricted to mountains and platforms, mainly in Subantarctic and Antarctic waters of the southern hemisphere, including the Southeast Pacific, Atlantic and Indian oceans and in areas surrounding the peninsular platforms of subantarctic islands. The aim of this work was to determine and characterize the gastrointestinal parasitic and microbial fauna of specimens of D. eleginoides captured in waters of the south-central zone of Chile. The magnitude of parasitism in D. eleginoides captured in waters of the south-central zone of Chile is variable, and the parasite richness is different from that reported in specimens from subantarctic environments. Next-generation sequencing (NGS) of the microbial community associated to intestine showed a high diversity, where Proteobacteria, Firmicutes, and Bacteriodetes were the dominant phyla. However, both parasitic and microbial structures can vary between fish from d...

Research paper thumbnail of Temperatures Outside the Optimal Range for Helicobacter pylori Increase Its Harboring within Candida Yeast Cells

Biology, 2021

Helicobacter pylori is capable of entering into yeast, but the factors driving this endosymbiosis... more Helicobacter pylori is capable of entering into yeast, but the factors driving this endosymbiosis remain unknown. This work aimed to determine if temperatures outside the optimal range for H. pylori increase its harboring within Candida. H. pylori strains were co-cultured with Candida strains in Brucella broth supplemented with 5% fetal bovine serum and incubated at 4, 25, 37 or 40 °C. After co-culturing, yeasts containing bacteria-like bodies (Y-BLBs) were observed by optical microscopy, and the bacterium were identified as H. pylori by FISH. The H. pylori 16S rRNA gene was amplified from the total DNA of Y-BLBs. The viability of intra-yeast H. pylori cells was confirmed using a viability assay. All H. pylori strains were capable of entering into all Candida strains assayed. The higher percentages of Y-BLBs are obtained at 40 °C with any of the Candida strains. H pylori also increased its harboring within yeast in co-cultures incubated at 25 °C when compared to those incubated at 3...

Research paper thumbnail of Antibiotics as a Stressing Factor Triggering the Harboring of Helicobacter pylori J99 within Candida albicans ATCC10231

Pathogens, 2021

First-line treatment for Helicobacter pylori includes amoxicillin and clarithromycin or metronida... more First-line treatment for Helicobacter pylori includes amoxicillin and clarithromycin or metronidazole plus a proton pump inhibitor. Treatment failure is associated with antibiotic resistance and possibly also with internalization of H. pylori into eukaryotic cells, such as yeasts. Factors triggering the entry of H. pylori into yeast are poorly understood. Therefore, the aim of this study was to evaluate whether clarithromycin or amoxicillin trigger the entry of H. pylori into C. albicans cells. Methods: H. pylori J99 and C. albicans ATCC 10231 were co-cultured in the presence of subinhibitory concentrations of amoxicillin and clarithromycin as stressors. Bacterial-bearing yeasts were observed by fresh examination. The viability of bacteria within yeasts was evaluated, confirming the entry of bacteria into Candida, amplifying, by PCR, the H. pylori16S rRNA gene in total yeast DNA. Results: Amoxicillin significantly increased the entry of H. pylori into C. albicans compared to the con...

Research paper thumbnail of The Administration of the Synbiotic Lactobacillus bulgaricus 6c3 Strain, Inulin and Fructooligosaccharide Decreases the Concentrations of Indoxyl Sulfate and Kidney Damage in a Rat Model

Toxins, 2021

Indoxyl sulfate (IS) is involved in the progression of chronic kidney disease (CKD) and in its ca... more Indoxyl sulfate (IS) is involved in the progression of chronic kidney disease (CKD) and in its cardiovascular complications. One of the approaches proposed to decrease IS is the administration of synbiotics. This work aimed to search for a probiotic strain capable to decrease serum IS levels and mix it with two prebiotics (inulin and fructooligosaccharide (FOS)) to produce a putative synbiotic and test it in a rat CKD model. Two groups of Sprague-Dawley rats were nephrectomized. One group (Lac) received the mixture for 16 weeks in drinking water and the other no (Nef). A control group (C) included sham-nephrectomized rats. Serum creatinine and IS concentrations were measured using high-performance liquid chromatography with diode array detector (HPLC-DAD). Optical microscopy and two-photon excitation microscopy was used to study kidney and heart samples. The Lac group, which received the synbiotic, reduced IS by 0.8% while the Nef group increased it by 38.8%. Histological analysis o...

Research paper thumbnail of Intracellular Presence of Helicobacter pylori and Its Virulence-Associated Genotypes within the Vaginal Yeast of Term Pregnant Women

Microorganisms, 2021

Background: Helicobacter pylori transmission routes are not entirely elucidated. Since yeasts are... more Background: Helicobacter pylori transmission routes are not entirely elucidated. Since yeasts are postulated to transmit this pathogen, this study aimed to detect and genotype intracellular H. pylori harbored within vaginal yeast cells. Methods: A questionnaire was used to determine risk factors of H. pylori infection. Samples were seeded on Sabouraud Dextrose Agar and horse blood-supplemented Columbia agar. Isolated yeasts were identified using and observed by optical microscopy searching for intra-yeast H. pylori. Total yeast DNA, from one random sample, was extracted to search for H. pylori virulence genes by PCR and bacterial identification by sequencing. Results: 43% of samples contained yeasts, mainly Candida albicans (91%). Microscopy detected bacteria such as bodies and anti-H. pylori antibodies binding particles in 50% of the isolated yeasts. Total DNA extracted showed that 50% of the isolated yeasts were positive for H. pylori 16S rDNA and the sequence showed 99.8% similar...

Research paper thumbnail of In Vitro Incorporation of Helicobacter pylori into Candida albicans Caused by Acidic pH Stress

Pathogens, 2020

Yeasts can adapt to a wide range of pH fluctuations (2 to 10), while Helicobacter pylori, a facul... more Yeasts can adapt to a wide range of pH fluctuations (2 to 10), while Helicobacter pylori, a facultative intracellular bacterium, can adapt to a range from pH 6 to 8. This work analyzed if H. pylori J99 can protect itself from acidic pH by entering into Candida albicans ATCC 90028. Growth curves were determined for H. pylori and C. albicans at pH 3, 4, and 7. Both microorganisms were co-incubated at the same pH values, and the presence of intra-yeast bacteria was evaluated. Intra-yeast bacteria-like bodies were detected using wet mounting, and intra-yeast binding of anti-H. pylori antibodies was detected using immunofluorescence. The presence of the H. pylori rDNA 16S gene in total DNA from yeasts was demonstrated after PCR amplification. H. pylori showed larger death percentages at pH 3 and 4 than at pH 7. On the contrary, the viability of the yeast was not affected by any of the pHs evaluated. H. pylori entered into C. albicans at all the pH values assayed but to a greater extent a...

Research paper thumbnail of Effect of the natural arsenic gradient on the diversity and arsenic resistance of bacterial communities of the sediments of Camarones River (Atacama Desert, Chile)

PloS one, 2018

Arsenic (As), a highly toxic metalloid, naturally present in Camarones River (Atacama Desert, Chi... more Arsenic (As), a highly toxic metalloid, naturally present in Camarones River (Atacama Desert, Chile) is a great health concern for the local population and authorities. In this study, the taxonomic and functional characterization of bacterial communities associated to metal-rich sediments from three sites of the river (sites M1, M2 and M3), showing different arsenic concentrations, were evaluated using a combination of approaches. Diversity of bacterial communities was evaluated by Illumina sequencing. Strains resistant to arsenic concentrations varying from 0.5 to 100 mM arsenite or arsenate were isolated and the presence of genes coding for enzymes involved in arsenic oxidation (aio) or reduction (arsC) investigated. Bacterial communities showed a moderate diversity which increased as arsenic concentrations decreased along the river. Sequences of the dominant taxonomic groups (abundances ≥1%) present in all three sites were affiliated to Proteobacteria (range 40.3-47.2%), Firmicut...

Research paper thumbnail of An Anaerobic Environment Drives the Harboring of Helicobacter pylori within Candida Yeast Cells

Biology

Helicobacter pylori protects itself from stressful environments by forming biofilms, changing its... more Helicobacter pylori protects itself from stressful environments by forming biofilms, changing its morphology, or invading eukaryotic cells, including yeast cells. There is little knowledge about the environmental factors that influence the endosymbiotic relationship between bacterium and yeasts. Here, we studied if oxygen availability stimulated the growth of H. pylori within Candida and if this was a bacterial- or yeast strain-dependent relationship. Four H. pylori strains and four Candida strains were co-cultured in Brucella broth plus 5% fetal bovine serum, and incubated under microaerobic, anaerobic, or aerobic conditions. Bacteria-like bodies (BLBs) within yeast cells (Y-BLBs) were detected by microscopy. H. pylori was identified by FISH and by PCR amplification of the 16S rRNA gene of H. pylori from total DNA extracted from Y-BLBs from H. pylori and Candida co-cultures. BLBs viability was confirmed by SYTO-9 fluorescence. Higher Y-BLB percentages were obtained under anaerobic ...

Research paper thumbnail of Analysis of epibiont data in relation with the Debilitated Turtle Syndrome of sea turtles in Chelonia mydas and Lepidochelys olivacea from Concepción coast, Chile

Latin American Journal of Aquatic Research

Epibionts on the surface of the skin and shell of a specimen of Chelonia mydas and three Lepidoch... more Epibionts on the surface of the skin and shell of a specimen of Chelonia mydas and three Lepidochelys olivacea found floating on the coast of Concepción, Chile, between June 2010 and December 2012, were analyzed. These epibionts were analyzed during the clinical inspection and the tissue changes related to its settlement, with filamentous algae around, were observed. Subsequently, the epibionts were identified by morphological observation. The knowledge about theses epibionts in Chile is reviewed and the potential occurrence of Debilitated Turtle Syndrome (DTS) in these turtles is discussed. The presence of sea turtles in the Chilean coast is considered a casual event, so there is little information on this issue. We propose it is necessary to carry out more studies on the association between turtles and epibionts because their identification, colonizing reptiles’ surface may give relevant information to a better understanding of different diseases, including DTS, that affect these ...

Research paper thumbnail of Gastrointestinal helminths of Humboldt penguin (Spheniscus humboldti Meyen, 1834) from south central Chile

Latin American Journal of Aquatic Research, 2019

The study of parasitism in penguins is relevant because it offers information on the biology and ... more The study of parasitism in penguins is relevant because it offers information on the biology and ecology of this host. This study reports the parasitism of 156 specimens of Spheniscus humboldti rescued from beaches of the south-central coast of Chile, between January 2006 and June 2015, describing their potential forms of transmission and pathogenicity. The parasitic infection was determined by coproparasitic methods in live specimens and by necropsy in dead penguins. The gastrointestinal helminths Tetrabothrius eudyptidis (Lönnberg, 1896), Cardiocephaloides physalis (Lutz, 1926), Contracaecum pelagicum (Johnston & Mawson, 1942) and Cosmocephalus obvelatus (Creplin, 1825) were identified by both methods. Parasitism was observed in 29.57% of live specimens and 51.76% of necropsied birds. All the parasites identified corresponded to genera already informed in S. humboldti. The richness of the S. humboldti parasitic fauna was lower than that reported for other species of penguins. The results demonstrate the participation of S. humboldti as a definitive host in the life cycles of the parasites reported in this study. Being S. humboldti a vulnerable species, it is necessary to continue with parasitological studies in this penguin to clarify the role of parasites in the health of these birds.

Research paper thumbnail of Biodegradation of roxarsone by a bacterial community of underground water and its toxic impact

World Journal of Microbiology and Biotechnology, 2015

Roxarsone is included in chicken food as anticoccidial and mainly excreted unchanged in faeces. M... more Roxarsone is included in chicken food as anticoccidial and mainly excreted unchanged in faeces. Microorganisms biotransform roxarsone into toxic compounds that leach and contaminate underground waters used for human consumption. This study evaluated roxarsone biotransformation by underground water microorganisms and the toxicity of the resulting compounds. Underground water from an agricultural field was used to prepare microcosms, containing 0.05 mM roxarsone, and cultured under aerobic or anaerobic conditions. Bacterial communities of microcosms were characterized by PCR-DGGE. Roxarsone degradation was measured by HPLC/HG/AAS. Toxicity was evaluated using HUVEC cells and the Toxi-ChromoTest kit. Roxarsone degradation analysis, after 15 days, showed that microcosms of underground water with nutrients degraded 90 and 83.3% of roxarsone under anaerobic and aerobic conditions, respectively. Microcosms without nutrients degraded 50 and 33.1% under anaerobic and aerobic conditions, respectively. Microcosms including nutrients showed more roxarsone conversion into toxic inorganic arsenic species. DGGE analyses showed the presence of Proteobacteria, Firmicutes, Actinobacteria, Planctomycetes and Spirochaetes. Toxicity assays showed that roxarsone biotransformation by underground water microorganisms in all microcosms generated degradation products toxic for eukaryotic and prokaryotic cells. Furthermore, toxicity increased when roxarsone leached though a soil column and was further transformed by the bacterial community present in underground water. Therefore, using underground water from areas where roxarsone containing manure is used as fertilizer might be a health risk.

Research paper thumbnail of Reducción de selenito a Selenio elemental por Pantoea agglomerans

Gayana, Jun 1, 2016

El selenio es esencial y requerido por distintos sistemas biológicos para su crecimiento y metabo... more El selenio es esencial y requerido por distintos sistemas biológicos para su crecimiento y metabolismo. Su transformación en el ambiente ocurre principalmente por microorganismos que reducen el selenito a selenio elemental. Pantoea agglomerans UC-32 reduce el selenito a nanopartículas de selenio elemental. El objetivo de este trabajo fue determinar la cinética de reducción de selenito a selenio elemental y la ubicación celular de la actividad reductora en Pantoea agglomerans UC-32. Se ensayó la actividad reductora de P. agglomerans frente a diferentes concentraciones de selenito, evaluándose la disminución de selenito y aparición de selenio elemental. La ubicación de la actividad reductora fue estudiada por fraccionamiento celular y zimograma. Al ensayar la actividad reductora de selenito se encontró que la enzima se satura a concentraciones bajas de este compuesto y el zimograma localizó esta actividad en la fracción citoplasmática y que requiere NADPH como coenzima. En conclusión, P. agglomerans es capaz de reducir selenito a selenio elemental insoluble inmovilizado en la biomasa en condiciones aeróbicas y que la enzima que cataliza esta reducción se localiza en la fracción de citoplasmática. Estas características permitirían la "síntesis verde" de nanopartículas de selenio las cuales tienen aplicación en la biorremediación de diferentes matrices, como suelo o agua contaminadas.

Research paper thumbnail of In vitro effect of Levamisole on Rainbow Trout (Oncorhynchus mykiss) peripheral blood mononuclear cells

Gayana (Concepción), 2015

In vitro effect of Levamisole on Rainbow Trout (Oncorhynchus mykiss) peripheral blood mononuclear... more In vitro effect of Levamisole on Rainbow Trout (Oncorhynchus mykiss) peripheral blood mononuclear cells Efecto in vitro del levamisol sobre las celulas mononucleares de la sangre periférica de trucha arcoíris (Oncorhynchus mykiss

Research paper thumbnail of In vitro cytotoxic capacity against tumor cell lines and antioxidant activity of acidic polysaccharides isolated from the Andean Patagonian fungus Phylloporia boldo

Natural Product Research

Fungal polysaccharides possess a broad biological activity, including cytotoxic and antioxidant a... more Fungal polysaccharides possess a broad biological activity, including cytotoxic and antioxidant activities. This work aimed to evaluate the cytotoxic and antioxidant activity of the acidic polysaccharides of Phylloporia boldo strain (named PBAP40). Cytotoxic activity of polysaccharide was evaluated determining the viability of three tumor cell lines by MTT assay. The effect of acidic polysaccharide on the cell cycle of HL-60 cell line was evaluated by flow cytometry, and the antioxidant activity was determined by DPPH and ABTS assays. PBAP40 showed cytotoxic effects in tumor cell lines. Results suggest that P. boldo acidic polysaccharides arrested tumor cells in the cell cycle Sub G1 phase. The acidic polysaccharides of PBAP40 strain were not cytotoxic for the non-tumor cell line. PBAP40 also showed excellent antioxidant activity. The FT-IR analysis of the acidic polysaccharides indicated the presence of glucans bearing α-and β-type glycosidic bonds.

Research paper thumbnail of EVALUATION OF CYTOTOXIC EFFECT AGAINST TUMOUR CELLS OF THE ACIDIC POLYSACCHARIDES OF THE FUNGUS Nothophellinus andinopatagonicus

Journal of the Chilean Chemical Society

Fungal polysaccharides possess an important bioactive potential, including antioxidant and antica... more Fungal polysaccharides possess an important bioactive potential, including antioxidant and anticarcinogenic activity. The aim of this work was to determine the antioxidant activity and cytotoxicity against tumour and non-tumour cell lines acidic polysaccharides (NAAPs) of the fungus Nothophellinus andinopatagonicus. The effect of NAAPs on tumour cells lines was evaluated by MTT assay and flow cytometry. The analyses determined that glucose was the most abundant monomer and IR spectrum showed the typical peaks of β-glucans in the NAAPs. The cell viability assays revealed significant activity of NAAPs against HL-60, HCT-116 and MCF-7 tumour cell lines (IC50 = 767,16 µg mL-1 , 1256 µg mL-1 and 4241,7 µg mL-1 , respectively); but a much lower cytotoxicity against the non-tumour cell line HGF-1 (outside the range of the highest concentration tested (>10 mg mL-1)). NAAPs affected the cell cycle of HL-60 tumour cells, increasing the percentage of cells in the sub G1 phase and reducing it in the S/G2/M phases. Moreover, low concentrations of NAAPs also showed an effective cytotoxic activity against tumour cell lines while the non-tumour cell line was unaffected, maintaining a viability close to 100%. The antioxidant activity of the highest NAAPs concentration tested was 6.24% and 4.63%, for DPPH and ABTS method, respectively.

Research paper thumbnail of Can Probiotics, Particularly Limosilactobacillus fermentum UCO-979C and Lacticaseibacillus rhamnosus UCO-25A, Be Preventive Alternatives against SARS-CoV-2?

Biology

COVID-19, an infection produced by the SARS-CoV-2 virus in humans, has rapidly spread to become a... more COVID-19, an infection produced by the SARS-CoV-2 virus in humans, has rapidly spread to become a high-mortality pandemic. SARS-CoV-2 is a single-stranded RNA virus characterized by infecting epithelial cells of the intestine and lungs, binding to the ACE2 receptor present on epithelial cells. COVID-19 treatment is based on antivirals and antibiotics against symptomatology in addition to a successful preventive strategy based on vaccination. At this point, several variants of the virus have emerged, altering the effectiveness of treatments and thereby attracting attention to several alternative therapies, including immunobiotics, to cope with the problem. This review, based on articles, patents, and an in silico analysis, aims to address our present knowledge of the COVID-19 disease, its symptomatology, and the possible beneficial effects for patients if probiotics with the characteristics of immunobiotics are used to confront this disease. Moreover, two probiotic strains, L. fermen...

Research paper thumbnail of Selenium Nanoparticle-Enriched and Potential Probiotic, Lactiplantibacillus plantarum S14 Strain, a Diet Supplement Beneficial for Rainbow Trout

Biology

Lactic acid bacteria (LAB), obtained from rainbow trout (Oncorhynchus mykiss) intestine, were cul... more Lactic acid bacteria (LAB), obtained from rainbow trout (Oncorhynchus mykiss) intestine, were cultured in MRS medium and probiotic candidates. Concurrently, producers of elemental selenium nanoparticles (Se0Nps) were selected. Probiotic candidates were subjected to morphological characterization and the following tests: antibacterial activity, antibiotic susceptibility, hemolytic activity, catalase, hydrophobicity, viability at low pH, and tolerance to bile salts. Two LAB strains (S4 and S14) satisfied the characteristics of potential probiotics, but only strain S14 reduced selenite to biosynthesize Se0Nps. S14 strain was identified, by 16S rDNA analysis, as Lactiplantibacillus plantarum. Electron microscopy showed Se0Nps on the surface of S14 cells. Rainbow trout diet was supplemented (108 CFU g−1 feed) with Se0Nps-enriched L. plantarum S14 (LABS14-Se0Nps) or L. plantarum S14 alone (LABS14) for 30 days. At days 0, 15, and 30, samples (blood, liver, and dorsal muscle) were obtained ...

Research paper thumbnail of Consumption of a Gelatin Supplemented with the Probiotic Strain Limosilactobacillus fermentum UCO-979C Prevents Helicobacter pylori Infection in a Young Adult Population Achieved

Foods

Helicobacter pylori is a bacterium associated with various gastrointestinal diseases of high worl... more Helicobacter pylori is a bacterium associated with various gastrointestinal diseases of high worldwide prevalence. Since probiotics are an emerging alternative to managing infection by this pathogenic bacterium, the present work evaluated, in a randomized double-blind study controlled by a placebo, if consuming Limosilactobacillus fermentum UCO-979C prevents H. pylori infection in humans. Participants consumed either L. fermentum UCO-979C-supplemented gelatin (67 participants) or placebo-supplemented gelatin (64 participants) once a day, five days per week for 12 weeks. H. pylori infection in the participants was controlled before and after the intervention detecting H. pylori antigens in stools. Regarding H. pylori-infected participants before the study, 100% remained infected at the end of the study in the placebo group, while 96.7% of those receiving the probiotic remained infected after the intervention. Most importantly, of the non-infected participants, 34.2% became infected a...

Research paper thumbnail of Nutrient Deficiency Promotes the Entry of Helicobacter pylori Cells into Candida Yeast Cells

Biology

Helicobacter pylori, a Gram-negative bacterium, has as a natural niche the human gastric epitheli... more Helicobacter pylori, a Gram-negative bacterium, has as a natural niche the human gastric epithelium. This pathogen has been reported to enter into Candida yeast cells; however, factors triggering this endosymbiotic relationship remain unknown. The aim of this work was to evaluate in vitro if variations in nutrient concentration in the cultured medium trigger the internalization of H. pylori within Candida cells. We used H. pylori–Candida co-cultures in Brucella broth supplemented with 1%, 5% or 20% fetal bovine serum or in saline solution. Intra-yeast bacteria-like bodies (BLBs) were observed using optical microscopy, while intra-yeast BLBs were identified as H. pylori using FISH and PCR techniques. Intra-yeast H. pylori (BLBs) viability was confirmed using the LIVE/DEAD BacLight Bacterial Viability kit. Intra-yeast H. pylori was present in all combinations of bacteria–yeast strains co-cultured. However, the percentages of yeast cells harboring bacteria (Y-BLBs) varied according to ...

Research paper thumbnail of Selenium Nanoparticles Biosynthesized by Pantoea agglomerans and Their Effects on Cellular and Physiological Parameters in the Rainbow Trout Oncorhynchus mykiss

Biology, 2022

The applications of nanoparticles (Nps) as food additives, health enhancers, and antimicrobials i... more The applications of nanoparticles (Nps) as food additives, health enhancers, and antimicrobials in animal production are increasing. The aim of this study was to evaluate the effect of selenium (Se) nanoparticles (Se0Nps) stabilized with L-cysteine (Se0Nps/L-Cys), as a nutritional supplement, on immunological, oxidative status, and productive parameters in O. mykiss. TEM and SEM-EDS showed the accumulation of spherical Se0Nps entirely composed by elemental selenium (Se0) as intracellular and extracellular deposits in Pantoea agglomerans UC-32 strain. The in vitro antioxidant capacity of Se0Nps/L-Cys was significant more efficient ROS scavengers than Se0Nps and Na2SeO3. We also evaluate the effect of Se0Nps/L-Cys on cell viability and oxidative stress in RTgill-W1, RTS-11, or T-PHKM Oncorhynchus mykiss cell lines. Se0Nps/L-Cys showed less toxic and high antioxidant activity than Se0Nps and Na2SeO3. Finally, the dietary Se0Nps/L-Cys had a significant better effect on both plasma lysoz...

Research paper thumbnail of Gastrointestinal Microbiota and Parasite-Fauna of Wild Dissostichus eleginoides Smitt, 1898 Captured at the South-Central Coast of Chile

Microorganisms, 2021

Dissotichus eleginoides has a discontinuous circumpolar geographic distribution restricted to mou... more Dissotichus eleginoides has a discontinuous circumpolar geographic distribution restricted to mountains and platforms, mainly in Subantarctic and Antarctic waters of the southern hemisphere, including the Southeast Pacific, Atlantic and Indian oceans and in areas surrounding the peninsular platforms of subantarctic islands. The aim of this work was to determine and characterize the gastrointestinal parasitic and microbial fauna of specimens of D. eleginoides captured in waters of the south-central zone of Chile. The magnitude of parasitism in D. eleginoides captured in waters of the south-central zone of Chile is variable, and the parasite richness is different from that reported in specimens from subantarctic environments. Next-generation sequencing (NGS) of the microbial community associated to intestine showed a high diversity, where Proteobacteria, Firmicutes, and Bacteriodetes were the dominant phyla. However, both parasitic and microbial structures can vary between fish from d...

Research paper thumbnail of Temperatures Outside the Optimal Range for Helicobacter pylori Increase Its Harboring within Candida Yeast Cells

Biology, 2021

Helicobacter pylori is capable of entering into yeast, but the factors driving this endosymbiosis... more Helicobacter pylori is capable of entering into yeast, but the factors driving this endosymbiosis remain unknown. This work aimed to determine if temperatures outside the optimal range for H. pylori increase its harboring within Candida. H. pylori strains were co-cultured with Candida strains in Brucella broth supplemented with 5% fetal bovine serum and incubated at 4, 25, 37 or 40 °C. After co-culturing, yeasts containing bacteria-like bodies (Y-BLBs) were observed by optical microscopy, and the bacterium were identified as H. pylori by FISH. The H. pylori 16S rRNA gene was amplified from the total DNA of Y-BLBs. The viability of intra-yeast H. pylori cells was confirmed using a viability assay. All H. pylori strains were capable of entering into all Candida strains assayed. The higher percentages of Y-BLBs are obtained at 40 °C with any of the Candida strains. H pylori also increased its harboring within yeast in co-cultures incubated at 25 °C when compared to those incubated at 3...

Research paper thumbnail of Antibiotics as a Stressing Factor Triggering the Harboring of Helicobacter pylori J99 within Candida albicans ATCC10231

Pathogens, 2021

First-line treatment for Helicobacter pylori includes amoxicillin and clarithromycin or metronida... more First-line treatment for Helicobacter pylori includes amoxicillin and clarithromycin or metronidazole plus a proton pump inhibitor. Treatment failure is associated with antibiotic resistance and possibly also with internalization of H. pylori into eukaryotic cells, such as yeasts. Factors triggering the entry of H. pylori into yeast are poorly understood. Therefore, the aim of this study was to evaluate whether clarithromycin or amoxicillin trigger the entry of H. pylori into C. albicans cells. Methods: H. pylori J99 and C. albicans ATCC 10231 were co-cultured in the presence of subinhibitory concentrations of amoxicillin and clarithromycin as stressors. Bacterial-bearing yeasts were observed by fresh examination. The viability of bacteria within yeasts was evaluated, confirming the entry of bacteria into Candida, amplifying, by PCR, the H. pylori16S rRNA gene in total yeast DNA. Results: Amoxicillin significantly increased the entry of H. pylori into C. albicans compared to the con...

Research paper thumbnail of The Administration of the Synbiotic Lactobacillus bulgaricus 6c3 Strain, Inulin and Fructooligosaccharide Decreases the Concentrations of Indoxyl Sulfate and Kidney Damage in a Rat Model

Toxins, 2021

Indoxyl sulfate (IS) is involved in the progression of chronic kidney disease (CKD) and in its ca... more Indoxyl sulfate (IS) is involved in the progression of chronic kidney disease (CKD) and in its cardiovascular complications. One of the approaches proposed to decrease IS is the administration of synbiotics. This work aimed to search for a probiotic strain capable to decrease serum IS levels and mix it with two prebiotics (inulin and fructooligosaccharide (FOS)) to produce a putative synbiotic and test it in a rat CKD model. Two groups of Sprague-Dawley rats were nephrectomized. One group (Lac) received the mixture for 16 weeks in drinking water and the other no (Nef). A control group (C) included sham-nephrectomized rats. Serum creatinine and IS concentrations were measured using high-performance liquid chromatography with diode array detector (HPLC-DAD). Optical microscopy and two-photon excitation microscopy was used to study kidney and heart samples. The Lac group, which received the synbiotic, reduced IS by 0.8% while the Nef group increased it by 38.8%. Histological analysis o...

Research paper thumbnail of Intracellular Presence of Helicobacter pylori and Its Virulence-Associated Genotypes within the Vaginal Yeast of Term Pregnant Women

Microorganisms, 2021

Background: Helicobacter pylori transmission routes are not entirely elucidated. Since yeasts are... more Background: Helicobacter pylori transmission routes are not entirely elucidated. Since yeasts are postulated to transmit this pathogen, this study aimed to detect and genotype intracellular H. pylori harbored within vaginal yeast cells. Methods: A questionnaire was used to determine risk factors of H. pylori infection. Samples were seeded on Sabouraud Dextrose Agar and horse blood-supplemented Columbia agar. Isolated yeasts were identified using and observed by optical microscopy searching for intra-yeast H. pylori. Total yeast DNA, from one random sample, was extracted to search for H. pylori virulence genes by PCR and bacterial identification by sequencing. Results: 43% of samples contained yeasts, mainly Candida albicans (91%). Microscopy detected bacteria such as bodies and anti-H. pylori antibodies binding particles in 50% of the isolated yeasts. Total DNA extracted showed that 50% of the isolated yeasts were positive for H. pylori 16S rDNA and the sequence showed 99.8% similar...

Research paper thumbnail of In Vitro Incorporation of Helicobacter pylori into Candida albicans Caused by Acidic pH Stress

Pathogens, 2020

Yeasts can adapt to a wide range of pH fluctuations (2 to 10), while Helicobacter pylori, a facul... more Yeasts can adapt to a wide range of pH fluctuations (2 to 10), while Helicobacter pylori, a facultative intracellular bacterium, can adapt to a range from pH 6 to 8. This work analyzed if H. pylori J99 can protect itself from acidic pH by entering into Candida albicans ATCC 90028. Growth curves were determined for H. pylori and C. albicans at pH 3, 4, and 7. Both microorganisms were co-incubated at the same pH values, and the presence of intra-yeast bacteria was evaluated. Intra-yeast bacteria-like bodies were detected using wet mounting, and intra-yeast binding of anti-H. pylori antibodies was detected using immunofluorescence. The presence of the H. pylori rDNA 16S gene in total DNA from yeasts was demonstrated after PCR amplification. H. pylori showed larger death percentages at pH 3 and 4 than at pH 7. On the contrary, the viability of the yeast was not affected by any of the pHs evaluated. H. pylori entered into C. albicans at all the pH values assayed but to a greater extent a...

Research paper thumbnail of Effect of the natural arsenic gradient on the diversity and arsenic resistance of bacterial communities of the sediments of Camarones River (Atacama Desert, Chile)

PloS one, 2018

Arsenic (As), a highly toxic metalloid, naturally present in Camarones River (Atacama Desert, Chi... more Arsenic (As), a highly toxic metalloid, naturally present in Camarones River (Atacama Desert, Chile) is a great health concern for the local population and authorities. In this study, the taxonomic and functional characterization of bacterial communities associated to metal-rich sediments from three sites of the river (sites M1, M2 and M3), showing different arsenic concentrations, were evaluated using a combination of approaches. Diversity of bacterial communities was evaluated by Illumina sequencing. Strains resistant to arsenic concentrations varying from 0.5 to 100 mM arsenite or arsenate were isolated and the presence of genes coding for enzymes involved in arsenic oxidation (aio) or reduction (arsC) investigated. Bacterial communities showed a moderate diversity which increased as arsenic concentrations decreased along the river. Sequences of the dominant taxonomic groups (abundances ≥1%) present in all three sites were affiliated to Proteobacteria (range 40.3-47.2%), Firmicut...

Research paper thumbnail of An Anaerobic Environment Drives the Harboring of Helicobacter pylori within Candida Yeast Cells

Biology

Helicobacter pylori protects itself from stressful environments by forming biofilms, changing its... more Helicobacter pylori protects itself from stressful environments by forming biofilms, changing its morphology, or invading eukaryotic cells, including yeast cells. There is little knowledge about the environmental factors that influence the endosymbiotic relationship between bacterium and yeasts. Here, we studied if oxygen availability stimulated the growth of H. pylori within Candida and if this was a bacterial- or yeast strain-dependent relationship. Four H. pylori strains and four Candida strains were co-cultured in Brucella broth plus 5% fetal bovine serum, and incubated under microaerobic, anaerobic, or aerobic conditions. Bacteria-like bodies (BLBs) within yeast cells (Y-BLBs) were detected by microscopy. H. pylori was identified by FISH and by PCR amplification of the 16S rRNA gene of H. pylori from total DNA extracted from Y-BLBs from H. pylori and Candida co-cultures. BLBs viability was confirmed by SYTO-9 fluorescence. Higher Y-BLB percentages were obtained under anaerobic ...

Research paper thumbnail of Analysis of epibiont data in relation with the Debilitated Turtle Syndrome of sea turtles in Chelonia mydas and Lepidochelys olivacea from Concepción coast, Chile

Latin American Journal of Aquatic Research

Epibionts on the surface of the skin and shell of a specimen of Chelonia mydas and three Lepidoch... more Epibionts on the surface of the skin and shell of a specimen of Chelonia mydas and three Lepidochelys olivacea found floating on the coast of Concepción, Chile, between June 2010 and December 2012, were analyzed. These epibionts were analyzed during the clinical inspection and the tissue changes related to its settlement, with filamentous algae around, were observed. Subsequently, the epibionts were identified by morphological observation. The knowledge about theses epibionts in Chile is reviewed and the potential occurrence of Debilitated Turtle Syndrome (DTS) in these turtles is discussed. The presence of sea turtles in the Chilean coast is considered a casual event, so there is little information on this issue. We propose it is necessary to carry out more studies on the association between turtles and epibionts because their identification, colonizing reptiles’ surface may give relevant information to a better understanding of different diseases, including DTS, that affect these ...

Research paper thumbnail of Gastrointestinal helminths of Humboldt penguin (Spheniscus humboldti Meyen, 1834) from south central Chile

Latin American Journal of Aquatic Research, 2019

The study of parasitism in penguins is relevant because it offers information on the biology and ... more The study of parasitism in penguins is relevant because it offers information on the biology and ecology of this host. This study reports the parasitism of 156 specimens of Spheniscus humboldti rescued from beaches of the south-central coast of Chile, between January 2006 and June 2015, describing their potential forms of transmission and pathogenicity. The parasitic infection was determined by coproparasitic methods in live specimens and by necropsy in dead penguins. The gastrointestinal helminths Tetrabothrius eudyptidis (Lönnberg, 1896), Cardiocephaloides physalis (Lutz, 1926), Contracaecum pelagicum (Johnston & Mawson, 1942) and Cosmocephalus obvelatus (Creplin, 1825) were identified by both methods. Parasitism was observed in 29.57% of live specimens and 51.76% of necropsied birds. All the parasites identified corresponded to genera already informed in S. humboldti. The richness of the S. humboldti parasitic fauna was lower than that reported for other species of penguins. The results demonstrate the participation of S. humboldti as a definitive host in the life cycles of the parasites reported in this study. Being S. humboldti a vulnerable species, it is necessary to continue with parasitological studies in this penguin to clarify the role of parasites in the health of these birds.

Research paper thumbnail of Biodegradation of roxarsone by a bacterial community of underground water and its toxic impact

World Journal of Microbiology and Biotechnology, 2015

Roxarsone is included in chicken food as anticoccidial and mainly excreted unchanged in faeces. M... more Roxarsone is included in chicken food as anticoccidial and mainly excreted unchanged in faeces. Microorganisms biotransform roxarsone into toxic compounds that leach and contaminate underground waters used for human consumption. This study evaluated roxarsone biotransformation by underground water microorganisms and the toxicity of the resulting compounds. Underground water from an agricultural field was used to prepare microcosms, containing 0.05 mM roxarsone, and cultured under aerobic or anaerobic conditions. Bacterial communities of microcosms were characterized by PCR-DGGE. Roxarsone degradation was measured by HPLC/HG/AAS. Toxicity was evaluated using HUVEC cells and the Toxi-ChromoTest kit. Roxarsone degradation analysis, after 15 days, showed that microcosms of underground water with nutrients degraded 90 and 83.3% of roxarsone under anaerobic and aerobic conditions, respectively. Microcosms without nutrients degraded 50 and 33.1% under anaerobic and aerobic conditions, respectively. Microcosms including nutrients showed more roxarsone conversion into toxic inorganic arsenic species. DGGE analyses showed the presence of Proteobacteria, Firmicutes, Actinobacteria, Planctomycetes and Spirochaetes. Toxicity assays showed that roxarsone biotransformation by underground water microorganisms in all microcosms generated degradation products toxic for eukaryotic and prokaryotic cells. Furthermore, toxicity increased when roxarsone leached though a soil column and was further transformed by the bacterial community present in underground water. Therefore, using underground water from areas where roxarsone containing manure is used as fertilizer might be a health risk.