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1.
J Appl Microbiol ; 135(5)2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38692848

RESUMO

AIM: Tarantulas are one of the largest predatory arthropods in tropical regions. Tarantulas though not lethal to humans, their venomous bite kills small animals and insect upon which they prey. To understand the abiotic and biotic components involved in Neotropical tarantula bites, we conducted a venom-microbiomics study in eight species from Costa Rica. METHODS AND RESULTS: We determined that the toxin profiles of tarantula venom are highly diverse using shotgun proteomics; the most frequently encountered toxins were ω-Ap2 toxin, neprilysin-1, and several teraphotoxins. Through culture-independent and culture-dependent methods, we determined the microbiota present in the venom and excreta to evaluate the presence of pathogens that could contribute to primary infections in animals, including humans. The presence of opportunistic pathogens with hemolytic activity was observed, with a prominence of Stenotrophomonas in the venoms. Other bacteria found in venoms and excreta with hemolytic activity included members of the genera Serratia, Bacillus, Acinetobacter, Microbacterium, and Morganella. CONCLUSIONS: Our data shed light on the venom- and gut-microbiome associated with Neotropical tarantulas. This information may be useful for treating bites from these arthropods in both humans and farm animals, while also providing insight into the toxins and biodiversity of this little-explored microenvironment.


Assuntos
Venenos de Aranha , Aranhas , Animais , Aranhas/microbiologia , Costa Rica , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/genética , Proteômica , Microbioma Gastrointestinal , Microbiota
2.
PLoS One ; 18(1): e0279914, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36652424

RESUMO

We studied the physicochemical characteristics and mycobiota associated to five key historic documents from Costa Rica, including the Independence Act of Costa Rica from 1821. We used nondestructive techniques (i.e., ATR-FTIR and XRF) to determine paper and ink composition. Results show that some documents are composed of cotton-based paper, whereas others were made of wood cellulose with an increased lignin content. We also determined that the ink employed in some of the documents is ferrogallic. Cultivation and molecular techniques were used to characterize the fungi inhabiting the documents. In total, 22 fungal isolates were obtained: 15 from the wood-cellulose-based documents and seven from the other three cotton-based. We also tested the cellulolytic activity of the recovered fungi; 95% of the fungi presented cellulolytic activity correlated to their ability to cause deterioration of the paper. Results suggest that cotton-based paper is the most resistant to fungal colonization and that most of the isolates have cellulolytic activity. This work increases the knowledge of the fungal diversity that inhabits historic documents and its relationship with paper composition and provides valuable information to develop strategies to conserve and restore these invaluable documents.


Assuntos
Celulose , Fungos , Costa Rica , Lignina , Madeira
3.
Microb Biotechnol ; 16(5): 931-946, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36682039

RESUMO

The soil bacterium Pseudomonas putida KT2440 has been shown to produce selenium nanoparticles aerobically from selenite; however, the molecular actors involved in this process are unknown. Here, through a combination of genetic and analytical techniques, we report the first insights into selenite metabolism in this bacterium. Our results suggest that the reduction of selenite occurs through an interconnected metabolic network involving central metabolic reactions, sulphur metabolism, and the response to oxidative stress. Genes such as sucA, D2HGDH and PP_3148 revealed that the 2-ketoglutarate and glutamate metabolism is important to convert selenite into selenium. On the other hand, mutations affecting the activity of the sulphite reductase decreased the bacteria's ability to transform selenite. Other genes related to sulphur metabolism (ssuEF, sfnCE, sqrR, sqr and pdo2) and stress response (gqr, lsfA, ahpCF and sadI) were also identified as involved in selenite transformation. Interestingly, suppression of genes sqrR, sqr and pdo2 resulted in the production of selenium nanoparticles at a higher rate than the wild-type strain, which is of biotechnological interest. The data provided in this study brings us closer to understanding the metabolism of selenium in bacteria and offers new targets for the development of biotechnological tools for the production of selenium nanoparticles.


Assuntos
Nanopartículas , Pseudomonas putida , Selênio , Pseudomonas putida/genética , Pseudomonas putida/metabolismo , Selênio/metabolismo , Nanopartículas/metabolismo , Ácido Selenioso/metabolismo , Estresse Oxidativo , Enxofre/metabolismo
4.
Environ Microbiome ; 18(1): 6, 2023 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-36658604

RESUMO

BACKGROUND: Río Celeste ("Sky-Blue River") is a river located in the Tenorio National Park (Costa Rica) that has become an important hotspot for eco-tourism due to its striking sky-blue color. A previous study indicated that this color is not caused by dissolved chemical species, but by formation of light-scattering aluminosilicate particles at the mixing point of two colorless streams, the acidic Quebrada Agria and the neutral Río Buenavista. RESULTS: We now present microbiological information on Río Celeste and its two tributaries, as well as a more detailed characterization of the particles that occur at the mixing point. Our results overturn the previous belief that the light scattering particles are formed by the aggregation of smaller particles coming from Río Buenavista, and rather point to chemical formation of hydroxyaluminosilicate colloids when Quebrada Agria is partially neutralized by Río Buenavista, which also contributes silica to the reaction. The process is mediated by the activities of different microorganisms in both streams. In Quebrada Agria, sulfur-oxidizing bacteria generate an acidic environment, which in turn cause dissolution and mobilization of aluminum and other metals. In Río Buenavista, the growth of diatoms transforms dissolved silicon into colloidal biogenic forms which may facilitate particle precipitation. CONCLUSIONS: We show how the sky-blue color of Río Celeste arises from the tight interaction between chemical and biological processes, in what constitutes a textbook example of emergent behavior in environmental microbiology.

5.
Fungal Biol ; 126(2): 101-112, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35078581

RESUMO

Living organisms can induce deterioration of cultural heritage. Conservation strategies aimed at avoiding damage and aiding restoration, require a comprehensive knowledge of structure, chemical composition, and identity of microorganisms that colonize artworks. The National Theatre of Costa Rica (NTCR), a building with historic architecture, houses several oil paintings from the nineteenth century, some with visible signs of biodeterioration. One of them is a large format painting on canvas called La Danza (size 9.83 × 5.13 m) from 1896 by Italian artist Vespasiano Bignami, located on the ceiling of the theatre's foyer. In the present study, we undertook a physicochemical and microbiological study of La Danza to identify the fungal species that inhabit the artwork and are responsible for the damage observed. Scanning electron microscope (SEM) images and attenuated total reflectance - Fourier transform infrared (ATR-FTIR) spectroscopic data indicated that the canvas material is made of hemp, the binder contains linseed oil and lead white, and a material in the inner face of the canvas is mainly composed of beeswax. Fungi were isolated onto potato dextrose agar (PDA) and carboxymethyl cellulose (CMC) agar, and then identified with molecular (BTUB, nrDNA ITS, and TEF1 regions) and morphological methods. Four isolates belonging to the genera Myxospora, Pestalotiopsis, Ustilago, and aff. Penicillium, were obtained. Qualitative tests showed cellulolytic activity in all isolated specimens, confirming their possible role in biodeterioration of the canvas. Phylogenetic and morphological data revealed a new species of Myxospora we name here as Myxospora theatro sp. nov., in reference to NTCR. The findings broaden the knowledge of fungi capable of inhabiting and damaging cultural heritage. They also provide valuable information to develop strategies for conservation and restoration of oil paintings on canvas.


Assuntos
Pinturas , Penicillium , Costa Rica , Fungos , Pinturas/história , Filogenia
6.
Microb Ecol ; 83(1): 83-99, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33864491

RESUMO

In this work, we studied the microbial community and the physicochemical conditions prevailing in an exploratory oil well, abandoned a century ago, located in the Cahuita National Park (Costa Rica). According to our analysis, Cahuita well is characterized by a continuous efflux of methane and the presence of a mixture of hydrocarbons including phenanthrene/anthracene, fluoranthene, pyrene, dibenzothiophene, tricyclic terpanes, pyrene, sesquiterpenes, sterane, and n-alkanes. Based on the analysis of 16S rRNA gene amplicons, we detected a significant abundance of methylotrophic bacteria such as Methylobacillus (6.3-26.0% of total reads) and Methylococcus (4.1-30.6%) and the presence of common genera associated with hydrocarbon degradation, such as Comamonas (0.8-4.6%), Hydrogenophaga (1.5-3.3%) Rhodobacter (1.0-4.9%), and Flavobacterium (1.1-6.5%). The importance of C1 metabolism in this niche was confirmed by amplifying the methane monooxygenase (MMO)-encoding gene (pmo) from environmental DNA and the isolation of two strains closely related to Methylorubrum rhodesianum and Paracoccus communis with the ability to growth using methanol and formate as sole carbon source respectively. In addition, we were able to isolated 20 bacterial strains from the genera Pseudomonas, Acinetobacter, and Microbacterium which showed the capability to grow using the hydrocarbons detected in the oil well as sole carbon source. This work describes the physicochemical properties and microbiota of an environment exposed to hydrocarbons for 100 years, and it not only represents a contribution to the understanding of microbial communities in environments with permanently high concentrations of these compounds but also has biotechnological implications for bioremediation of petroleum-polluted sites.


Assuntos
Microbiota , Petróleo , Bactérias , Biodegradação Ambiental , Hidrocarbonetos/metabolismo , Campos de Petróleo e Gás , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo
7.
Antonie Van Leeuwenhoek ; 114(4): 379-398, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33587228

RESUMO

Streptomyces symbionts in insects have shown to be a valuable source of new antibiotics. Here, we report the genome sequence and the potential for antibiotic production of "Streptomyces sp. M54", an Actinobacteria associated with the eusocial wasp, Polybia plebeja. The Streptomyces sp. M54 genome is composed of a chromosome (7.96 Mb), and a plasmid (1.91 Kb) and harbors 30 biosynthetic gene clusters for secondary metabolites, of which only one third has been previously characterized. Growth inhibition bioassays show that this bacterium produces antimicrobial compounds that are active against Hirsutella citriformis, a natural fungal enemy of its host, and the human pathogens Staphylococcus aureus and Candida albicans. Analyses through TLC-bioautography, LC-MS/MS and NMR allowed the identification of five macrocyclic ionophore antibiotics, with previously reported antibacterial, antitumor and antiviral properties. Phylogenetic analyses placed Streptomyces sp. M54 in a clade of other host-associated strains taxonomically related to Streptomyces griseus. Pangenomic and ANI analyses confirm the identity of one of its closest relatives as Streptomyces sp. LaPpAH-199, a strain isolated from an ant-plant symbiosis in Africa. In summary, our results suggest an insect-microbe association in distant geographic areas and showcase the potential of Streptomyces sp. M54 and related strains for the discovery of novel antibiotics.


Assuntos
Actinobacteria , Streptomyces , Vespas , Actinobacteria/genética , Animais , Antibacterianos/farmacologia , Cromatografia Líquida , Humanos , Hypocreales , Filogenia , Streptomyces/genética , Espectrometria de Massas em Tandem
8.
Extremophiles ; 25(1): 85-99, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33416983

RESUMO

Aquatic environments of volcanic origin provide an exceptional opportunity to study the adaptations of microorganisms to early planet life conditions. Here, we characterized the prokaryotic communities and physicochemical properties of seepage sites at the bottom of the Poas Volcano crater and the Agrio River, two geologically related extremely acidic environments located in Costa Rica. Both locations hold a low pH (1.79-2.20) and have high sulfate and iron concentrations (Fe = 47-206 mg/L, SO42- = 1170-2460 mg/L), but significant differences in their temperature (90.0-95.0 ºC in the seepages at Poas Volcano, 19.1-26.6 ºC in Agrio River) and in the elemental sulfur content. Based on the analysis of 16S rRNA gene sequences, we determined that Sulfobacillus spp. represented more than half of the sequences in Poas Volcano seepage sites, while Agrio River was dominated by Leptospirillum and members of the archaeal order Thermoplasmatales. Both environments share some chemical characteristics and part of their microbiota, however, the temperature and the reduced sulfur are likely the main distinguishing features, ultimately shaping their microbial communities. Our data suggest that in the Poas Volcano-Agrio River system there is a common metabolism but with specialization of species that adapt to the physicochemical conditions of each environment.


Assuntos
Temperatura Alta , Microbiota , Filogenia , Enxofre , Ácidos , Archaea/classificação , Bactérias/classificação , Costa Rica , Concentração de Íons de Hidrogênio , RNA Ribossômico 16S/genética , Rios , Erupções Vulcânicas
9.
Rev. chil. neuropsicol. (En línea) ; 15(1): 26-31, oct. 2020. tab
Artigo em Espanhol | LILACS | ID: biblio-1353715

RESUMO

Las mujeres con trasplante renal (TR) suelen cursar un embarazo de alto riesgo, pues son más susceptibles a presentar complicaciones médicas. Aunado a este hecho pueden presentar alteraciones en su estado emocional y psicológico durante y después del embarazo, lo que impactaría directamente en el estilo de crianza y desarrollo posterior del niño. Se desconoce cómo son los estilos de crianza en los hijos de las mujeres con TR y el posible impacto en su funcionamiento cognoscitivo. El presente trabajo tuvo dos objetivos: 1) determinar si existían diferencias en los estilos de crianza y las funciones cognoscitivas de los hijos de mujeres con trasplante renal en comparación con los hijos de mujeres sanas y 2) identificar la asociación entre las variables asociadas al riesgo en el embarazo y los estilos de crianza con las funciones cognoscitivas. Para ello fueron reclutados de diversos centros de trasplantes 23 niños (9 casos y 14 controles) de 7-15 años con sus respectivas madres a quienes se evaluó mediante el WISC-IV y el cuestionario CRPBI. Las madres fueron evaluadas con el cuestionario BRIEF, el cuestionario PCRI-M y el BDI-II. Se realizó un diseño transversal con alcance correlacional. No se encontraron diferencias entre el grupo caso y control en los estilos de crianza ni en las funciones cognoscitivas. Sin embargo, sí se encontró asociación entre los estilos de crianza y las funciones cognoscitivas. Un estilo en el que predomine la comunicación y la disciplina se asocia con mejores resultados cognoscitivos y conductuales.


Pregnancy in Kidney Transplant (KT) recipients is usually considered of high risk. KT recipients are susceptible to have obstetric complications. Studies report that KT recipients are at higher risk of experiencing distress during and after pregnancy, situation that may have an impact in parenting styles and child's development. Characteristics of parenting styles in KT recipients' offspring and its possible impact in cognitive functions remain unknown. The aims of the study were: 1) to determine if there are differences in parenting styles and cognitive functions among KT recipients' offspring and healthy women's offspring, and 2) to identify associations between high risk pregnancy variables, parenting styles and cognitive functions. Twenty-three children (9 cases and 14 controls) aged 8-15 years and their mothers were assessed with the (WISC-V) and the CRPBI. Mothers were asked to complete BRIEF, PCRI-M, BDI-II and a socioeconomic status instrument. A transversal correlational design was performed. No differences were found between case and control group in parenting styles or cognitive functions. However, an association between parenting styles and cognitive functions was found. Being raised with communication and discipline is associated with increased cognitive results.


Assuntos
Humanos , Masculino , Feminino , Criança , Adolescente , Transplante de Rim/efeitos adversos , Cognição , Gravidez de Alto Risco , Função Executiva , Educação Infantil , Estudos Transversais , Inquéritos e Questionários , Fatores de Risco
10.
Microb Ecol ; 80(4): 793-808, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32572534

RESUMO

We describe the geochemistry and microbial diversity of a pristine environment that resembles an acid rock drainage (ARD) but it is actually the result of hydrothermal and volcanic influences. We designate this environment, and other comparable sites, as volcanic influenced acid rock drainage (VARD) systems. The metal content and sulfuric acid in this ecosystem stem from the volcanic milieu and not from the product of pyrite oxidation. Based on the analysis of 16S rRNA gene amplicons, we report the microbial community structure in the pristine San Cayetano Costa Rican VARD environment (pH = 2.94-3.06, sulfate ~ 0.87-1.19 g L-1, iron ~ 35-61 mg L-1 (waters), and ~ 8-293 g kg-1 (sediments)). San Cayetano was found to be dominated by microorganisms involved in the geochemical cycling of iron, sulfur, and nitrogen; however, the identity and abundance of the species changed with the oxygen content (0.40-6.06 mg L-1) along the river course. The hypoxic source of San Cayetano is dominated by a putative anaerobic sulfate-reducing Deltaproteobacterium. Sulfur-oxidizing bacteria such as Acidithiobacillus or Sulfobacillus are found in smaller proportions with respect to typical ARD. In the oxic downstream, we identified aerobic iron-oxidizers (Leptospirillum, Acidithrix, Ferrovum) and heterotrophic bacteria (Burkholderiaceae bacterium, Trichococcus, Acidocella). Thermoplasmatales archaea closely related to environmental phylotypes found in other ARD niches were also observed throughout the entire ecosystem. Overall, our study shows the differences and similarities in the diversity and distribution of the microbial communities between an ARD and a VARD system at the source and along the oxygen gradient that establishes on the course of the river.


Assuntos
Archaea/isolamento & purificação , Bactérias/isolamento & purificação , Microbiota/fisiologia , Oxigênio/análise , Costa Rica , Concentração de Íons de Hidrogênio , RNA Arqueal/análise , RNA Bacteriano/análise , RNA Ribossômico 16S/análise , Rios , Erupções Vulcânicas
11.
Transbound Emerg Dis ; 67(1): 377-387, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31529612

RESUMO

Parvoviruses in the genera Bocaparvovirus (HBoV), Erythroparvovirus (B19) and Tetraparvovirus (PARV4) are the only autonomous parvoviruses known to be associated with human and non-human primates based on studies and clinical cases in humans worldwide and non-human primates in Asia and Africa. Here, the presence of these agents with pathogenic potential was assessed by PCR in blood and faeces from 55 howler monkeys, 112 white-face monkeys, 3 squirrel monkeys and 127 spider monkeys in Costa Rica and El Salvador. Overall, 3.7% (11/297) of the monkeys had HboV DNA, 0.67% (2/297) had B19 DNA, and 14.1% (42/297) had PARV4 DNA, representing the first detection of these viruses in New World Primates (NWP). Sex was significantly associated with the presence of HBoV, males having greater risk up to nine times compared with females. Captivity was associated with increased prevalence for PARV4 and when all viruses were analysed together. This study provides compelling molecular evidence of parvoviruses in NWPs and underscores the importance of future research aimed at understanding how these viruses behave in natural environments of the Neotropics and what variables may favour their presence and transmission.


Assuntos
Haplorrinos/virologia , Infecções por Parvoviridae/veterinária , Parvovirinae/isolamento & purificação , Primatas/virologia , Animais , Bocavirus/genética , Bocavirus/isolamento & purificação , América Central/epidemiologia , Fezes/virologia , Feminino , Humanos , Masculino , Infecções por Parvoviridae/epidemiologia , Infecções por Parvoviridae/virologia , Parvovirinae/genética , Reação em Cadeia da Polimerase/veterinária , Prevalência
12.
Extremophiles ; 23(2): 177-187, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30600357

RESUMO

Here we report the chemical and microbial characterization of the surface water of a CO2-rich hydrothermal vent known in Costa Rica as Borbollones, located at Tenorio Volcano National Park. The Borbollones showed a temperature surrounding 60 °C, a pH of 2.4 and the gas released has a composition of ~ 97% CO2, ~ 0.07% H2S, ~ 2.3% N2 and ~ 0.12% CH4. Other chemical species such as sulfate and iron were found at high levels with respect to typical fresh water bodies. Analysis by 16S rRNA gene metabarcoding revealed that in Borbollones predominates an archaeon from the order Thermoplasmatales and one bacterium from the genus Sulfurimonas. Other sulfur- (genera Thiomonas, Acidithiobacillus, Sulfuriferula, and Sulfuricurvum) and iron-oxidizing bacteria (genera Sideroxydans, Gallionella, and Ferrovum) were identified. Our results show that CO2-influenced surface water of Borbollones contains microorganisms that are usually found in acid rock drainage environments or sulfur-rich hydrothermal vents. To our knowledge, this is the first microbiological characterization of a CO2-dominated hydrothermal spring from Central America and expands our understanding of those extreme ecosystems.


Assuntos
Bactérias/isolamento & purificação , Fontes Termais/microbiologia , Microbiota , Enxofre/metabolismo , Thermoplasmales/isolamento & purificação , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Filogenia , RNA Ribossômico 16S/genética , Thermoplasmales/classificação , Thermoplasmales/genética , Termotolerância
13.
J Matern Fetal Neonatal Med ; 32(4): 542-549, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28988522

RESUMO

OBJECTIVE: The number of successful pregnancies in kidney transplant (KT) recipients has increased in recent years. Little evidence is available about the risk of in utero immunosuppressive exposure for long-term cognitive consequences. The aim of this study was to evaluate the impact of immunosuppression during pregnancy on intellectual performance of children born to KT recipients. METHODS: Using a cross-sectional design, women who had undergone KT and their children (aged 4+ years) were recruited at the outpatient follow-up in five transplant centers. Women who did not receive immunosuppression during pregnancy with similar distributions of socioeconomic status and length of gestation and their children were also recruited. Children were assessed with Wechsler Intelligence Scales. RESULTS: The study sample included 50 exposed and 50 unexposed children. No differences between groups in all the proposed confounding factors were found. Full-scale IQ did not differ significantly between both groups. Also, significant differences in any index or subscale score were not observed, with the exception of time required to complete the Wechsler preschool and primary scale of intelligence (WPPSI) Zoo locations subtest, which was done quicker in the unexposed group (p = .007). Exposure to immunosuppression during pregnancy was not a significant predictor of low IQ in logistic regression after adjustment for other factors. CONCLUSIONS: Immunosuppression therapy during pregnancy of KT women did not affect global intellectual performance of their offspring, except maybe for visuospatial working memory in preschool children.


Assuntos
Imunossupressores/efeitos adversos , Inteligência/efeitos dos fármacos , Rim , Efeitos Tardios da Exposição Pré-Natal/induzido quimicamente , Transplantados , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Transplante de Rim , Modelos Logísticos , Masculino , Memória de Curto Prazo/efeitos dos fármacos , Pessoa de Meia-Idade , Gravidez , Escalas de Wechsler
14.
Sci Rep ; 8(1): 7492, 2018 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-29748544

RESUMO

The archive of the Universidad de Costa Rica maintains a nineteenth-century French collection of drawings and lithographs in which the biodeterioration by fungi is rampant. Because of nutritional conditions in which these fungi grew, we suspected that they possessed an ability to degrade cellulose. In this work our goal was to isolate and identify the fungal species responsible for the biodegradation of a nineteenth-century art collection and determine their cellulolytic activity. Fungi were isolated using potato-dextrose-agar (PDA) and water-agar with carboxymethyl cellulose (CMC). The identification of the fungi was assessed through DNA sequencing (nrDNA ITS and α-actin regions) complemented with morphological analyses. Assays for cellulolytic activity were conducted with Gram's iodine as dye. Nineteen isolates were obtained, of which seventeen were identified through DNA sequencing to species level, belonging mainly to genera Arthrinium, Aspergillus, Chaetomium, Cladosporium, Colletotrichum, Penicillium and Trichoderma. For two samples that could not be identified through their ITS and α-actin sequences, a morphological analysis was conducted; they were identified as new species, named Periconia epilithographicola sp. nov. and Coniochaeta cipronana sp. nov. Qualitative tests showed that the fungal collection presents important cellulolytic activity.


Assuntos
Arte , Celulose/metabolismo , Fungos/isolamento & purificação , Fungos/metabolismo , Arte/história , Biodegradação Ambiental , Costa Rica , Gravuras e Gravação/história , Fungos/classificação , História do Século XIX , Humanos , Papel
15.
Extremophiles ; 21(2): 235-243, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27933457

RESUMO

Whether the extreme conditions of acidity and heavy metal pollution of streams and rivers originating in pyritic formations are caused primarily by mining activities or by natural activities of metal-oxidizing microbes living within the geological formations is a subject of considerable controversy. Most microbiological studies of such waters have so far focused on acid mine drainage sites, which are heavily human-impacted environments, so it has been problematic to eliminate the human factor in the question of the origin of the key metal compounds. We have studied the physico-chemistry and microbiology of the Río Sucio in the Braulio Carrillo National Park of Costa Rica, 22 km from its volcanic rock origin. Neither the remote origin, nor the length of the river to the sampling site, have experienced human activity and are thus pristine. The river water had a characteristic brownish-yellow color due to high iron-dominated minerals, was slightly acidic, and rich in chemolithoautotrophic iron- and sulfur-oxidizing bacteria, dominated by Gallionella spp. Río Sucio is thus a natural acid-rock drainage system whose metal-containing components are derived primarily from microbial activities.


Assuntos
Crescimento Quimioautotrófico/fisiologia , Gallionellaceae/fisiologia , Rios/microbiologia , Microbiologia da Água , Costa Rica , Humanos
16.
Sci Rep ; 6: 37155, 2016 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-27845437

RESUMO

Selenium (Se) is an essential element for the cell that has multiple applications in medicine and technology; microorganisms play an important role in Se transformations in the environment. Here we report the previously unidentified ability of the soil bacterium Pseudomonas putida KT2440 to synthesize nanoparticles of elemental selenium (nano-Se) from selenite. Our results show that P. putida is able to reduce selenite aerobically, but not selenate, to nano-Se. Kinetic analysis indicates that, in LB medium supplemented with selenite (1 mM), reduction to nano-Se occurs at a rate of 0.444 mmol L-1 h-1 beginning in the middle-exponential phase and with a final conversion yield of 89%. Measurements with a transmission electron microscope (TEM) show that nano-Se particles synthesized by P. putida have a size range of 100 to 500 nm and that they are located in the surrounding medium or bound to the cell membrane. Experiments involving dynamic light scattering (DLS) show that, in aqueous solution, recovered nano-Se particles have a size range of 70 to 360 nm. The rapid kinetics of conversion, easy retrieval of nano-Se and the metabolic versatility of P. putida offer the opportunity to use this model organism as a microbial factory for production of selenium nanoparticles.


Assuntos
Nanopartículas Metálicas , Pseudomonas putida/metabolismo , Selênio/metabolismo , Oxirredução , Pseudomonas putida/ultraestrutura , Ácido Selenioso/metabolismo
17.
J Wildl Dis ; 52(2): 373-7, 2016 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-26967127

RESUMO

Several highly infectious diseases can be transmitted through feces and cause elevated mortality among carnivore species. One such infectious agent, canine distemper virus (CDV; Paramyxoviridae: Morbillivirus), has been reported to affect wild carnivores, among them several felid species. We screened free-ranging and captive wild carnivores in Costa Rica for CDV. Between 2006 and 2012, we collected 306 fecal samples from 70 jaguars (Panther onca), 71 ocelots ( Leopardus pardalis ), five jaguarundis (Puma yaguaroundi), 105 pumas ( Puma concolor ), five margays ( Leopardus wiedii ), 23 coyotes ( Canis latrans ), and 27 undetermined Leopardus spp. We found CDV in six individuals: one captive jaguarundi (rescued in 2009), three free-ranging ocelots (samples collected in 2012), and two free-ranging pumas (samples collected in 2007). Phylogenetic analyses were performed using sequences of the phosphoprotein (P) gene. We provide evidence of CDV in wild carnivores in Costa Rica and sequence data from a Costa Rican CDV isolate, adding to the very few sequence data available for CDV isolates from wild Central American carnivores.


Assuntos
Animais Selvagens , Vírus da Cinomose Canina/isolamento & purificação , Felidae , Panleucopenia Felina/virologia , Animais , Gatos , Costa Rica/epidemiologia , Vírus da Cinomose Canina/genética , Panleucopenia Felina/epidemiologia , Filogenia
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