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1.
Arch Microbiol ; 204(3): 184, 2022 Feb 18.
Artículo en Inglés | MEDLINE | ID: mdl-35179654

RESUMEN

Antimicrobial peptides (AMP) are promising novel antibiotics but exhibit low stability and can be toxic. The AMP encapsulation can be used to protect the drug and control its release rates. The Lr-AMP1f encapsulated into chitosan nanoparticle (NP) by ionic gelation method reached 90% efficiency. The results indicated that the hydrodynamic particle size of NPs increased from 196.1 ± 3.14 nm (free NP) to 228.1 ± 12.22 nm (nanoencapsulated Lr-AMP1f), while the atomic force microscope showed the spherical shape. The Zeta potential of the nanoencapsulated Lr-AMP1f was high (+ 35 mV). These AMP-loaded NPs exhibited stability for up to 21 days of storage. The minimum inhibitory concentration (MIC) of free Lr-AMP1f was 8 µg/mL for E. coli and S. epidermidis. However, the nanoencapsulated Lr-AMP1f produced a bacteriostatic effect against both bacteria at 8 µg/mL. The MIC of nanoencapsulated Lr-AMP1f was 16 µg/mL for E. coli and 32 for S. epidermidis. Nanoencapsulated Lr-AMP1f was nontoxic to HEK293 cells. Promisingly, chitosan NP can be used as a vehicle for the antibacterial application of new AMP (Lr-AMP1f).


Asunto(s)
Quitosano , Lippia , Antibacterianos/química , Antibacterianos/farmacología , Péptidos Antimicrobianos , Quitosano/farmacología , Escherichia coli , Células HEK293 , Humanos , Tamaño de la Partícula
2.
J Biomater Sci Polym Ed ; 33(5): 627-650, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-34807809

RESUMEN

Cellulose nanofibers (CNFs) are natural polymers with physical-chemical properties that make them very attractive for modulating stem cell differentiation, a crucial step in tissue engineering and regenerative medicine. Although cellulose is cytocompatible, when materials are in nanoscale, they become more reactive, needing to evaluate its potential toxic effect to ensure safe application. This study aimed to investigate the cytocompatibility of cotton CNF and its differentiation capacity induction on stem cells from human exfoliated deciduous teeth. First, the cotton CNF was characterized. Then, the cytocompatibility and the osteogenic differentiation induced by cotton CNF were examined. The results revealed that cotton CNFs have about 6-18 nm diameters, and the zeta potential was -10 mV. Despite gene expression alteration, the cotton CNF shows good cytocompatibility. The cotton CNF induced an increase in phosphatase alkaline activity and extracellular matrix mineralization. The results indicate that cotton CNF has good cytocompatibility and can promote cell differentiation without using chemical inducers, showing great potential as a new differentiation inductor for tissue engineering and regenerative medicine applications.


Asunto(s)
Nanofibras , Osteogénesis , Diferenciación Celular , Celulosa/farmacología , Humanos , Nanofibras/química , Medicina Regenerativa , Células Madre , Ingeniería de Tejidos , Diente Primario
3.
Nanotechnology ; 33(6)2021 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-34700304

RESUMEN

Carboxylated multi-wall carbon nanotube (MWCNT-COOH) presents unique properties due to nanoscale dimensions and permits a broad range of applications in different fields, such as bone tissue engineering and regenerative medicine. However, the cytocompatibility of MWCNT-COOH with human stem cells is poorly understood. Thus, studies elucidating how MWCNT-COOH affects human stem cell viability are essential to a safer application of nanotechnologies. Using stem cells from the human exfoliated deciduous teeth model, we have evaluated the effects of MWCNT-COOH on cell viability, oxidative cell stress, and DNA integrity. Results demonstrated that despite the decreased metabolism of mitochondria, MWCNT-COOH had no toxicity against stem cells. Cells maintained viability after MWCNT-COOH exposure. MWCNT-COOH did not alter the superoxide dismutase activity and did not cause genotoxic effects. The present findings are relevant to the potential application of MWCNT-COOH in the tissue engineering and regenerative medicine fields.


Asunto(s)
Nanomedicina , Nanotubos de Carbono/toxicidad , Células Madre , Ingeniería de Tejidos , Diente Primario/citología , Ácidos Carboxílicos/toxicidad , Supervivencia Celular/efectos de los fármacos , Humanos , Células Madre/citología , Células Madre/efectos de los fármacos
4.
Toxicol Res (Camb) ; 10(3): 511-522, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-34141165

RESUMEN

The titanium dioxide nanoparticles (NPs) have been applied to biomedical, pharmaceutical, and food additive fields. However, the effect on health and the environment are conflicting; thus, it has been reviewing several times. In this context, establishing standard robust protocols for detecting cytotoxicity and genotoxicity of nanomaterials became essential for nanotechnology development. The cell type and the intrinsic characteristics of titanium dioxide NPs can influence nanotoxicity. In this work, the cyto- and genotoxicity effects of standard reference material titanium dioxide NPs in primary bovine fibroblasts and immortalized Chinese hamster ovary epithelial (CHO) cells were determined and compared for the first time. Titanium dioxide NPs exposure revealed no cytotoxicity for primary bovine fibroblasts, while only higher concentrations tested (10 µg/ml) induce genotoxic effects in this cell model. In contrast, the lower concentrations of the titanium dioxide NPs cause the cyto- and genotoxic effects in CHO cells. Therefore, our finding indicates that the CHO line was more sensitive toward the effects of titanium dioxide NPs than the primary bovine fibroblast, which should be valuable for their environmental risk assessment.

6.
Environ Toxicol Pharmacol ; 81: 103546, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33186674

RESUMEN

Many types of nanocomposites employed in food packaging are based on silver nanoparticles (AgNP) because of their antibacterial properties, which can increase food shelf-life. As the commercialization of AgNP products has been expanding, the released of such nanoparticles in the environment has caused enormous concern, once they can pose potential risks to the environment and human beings. For instance, exposure of the maternal environment to nanomaterials during pregnancy may impact the health of the dam, fetus and offspring. In this context, here we investigated the effects of prenatal exposure of AgNP on the pregnancy outcomes of dams and postnatal development of their offspring. Pregnant Wistar rats were exposed to distinct AgNP concentrations (0, 1, 3 and 5 µg/kg/day) from beginning to the end of pregnancy. At parturition, newborns were observed regarding clinical signs of toxicity and survival rate. The offspring was examined by evaluating developmental endpoints. A delay in time for vaginal opening and testes descent were detected in the offspring exposed to AgNP during embryonic development. Our results indicate that prenatal exposure to AgNP can compromise neonatal rats' postnatal development, especially the reproductive features.


Asunto(s)
Nanopartículas del Metal/toxicidad , Efectos Tardíos de la Exposición Prenatal , Plata/toxicidad , Animales , Desarrollo Embrionario/efectos de los fármacos , Femenino , Masculino , Intercambio Materno-Fetal , Embarazo , Ratas Wistar , Testículo/efectos de los fármacos , Testículo/crecimiento & desarrollo , Vagina/efectos de los fármacos , Vagina/crecimiento & desarrollo
7.
J Nanosci Nanotechnol ; 20(10): 6532-6541, 2020 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-32385010

RESUMEN

Cellulose nanofibers have mechanical properties that make them very attractive in a myriad of fields such as biomedicine, tissue engineering, biosensors, cosmetics and food packet products. To evaluate the potential health risks of airborne cellulose nanofibers, the cellulose nanofiber was prepared and characterized and then its pulmonary potential toxicity to a mouse model was studied. Cellulose nanofiber has been prepared by acid hydrolysis of cotton cellulose and characterized by transmission electron microscopy, zeta potential and X-ray diffraction analysis. Then, using a short-term inhalation test, the pulmonary biocompatibility of cotton cellulose nanofibers at different concentrations (0.5 mg/mL, 1 mg/mL and 2 mg/mL) were evaluated. Transmission electron images showed needle-shaped particle with a diameter of about 6-18 nm and a length of 85-225 µm. Zeta potential was -25.3±7.80 mV and the X-ray diffraction patterns indicate that cotton cellulose nanofiber has pure structural characteristics. The In Vivo results revealed that the exposure to cotton cellulose nanofiber did not alter the number of inflammatory cells or cytokine secretion by lung cells (p > 0.05). The results demonstrate that the cotton cellulose nanofiber is biocompatible and it is an environment-friendly nanomaterial with promise in various industrial sectors.


Asunto(s)
Nanofibras , Animales , Celulosa , Ratones , Microscopía Electrónica de Transmisión , Nanofibras/toxicidad , Textiles , Difracción de Rayos X
8.
J Dairy Res ; 86(3): 307-314, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31451129

RESUMEN

This study aimed to evaluate the transcriptional changes occurring in isolated perfused mammary alveolar tissue in response to inoculation with S. agalactiae and to identify the most affected biological functions and pathways after 3 h. Four udders taken at slaughter from cows with healthy mammary gland were perfused ex situ with warmed and gassed Tyrode's solution. Mammary alveolar tissue samples were taken from the left fore and rear quarters (IQ-inoculated quarters) before inoculation (hour 0) and at 3 h post inoculation (hpi) and at the same times from control right fore and rear quarters (not inoculated: NIQ). A total of 1756 differentially expressed genes (DEGs) were identified between IQ and NIQ at 3 hpi using edgeR package. Within this set of DEGs, 952 were up regulated and mainly involved with innate immune response and inflammatory response, e.g., CD14, CCL5, TLR2, IL-8, SAA3, as well as in transcriptional regulation such as FOS, STAT3 and NFKBIA. Genes down-regulated (804) included those involved with lipid synthesis e.g., APOC2, SCD, FABP3 and FABP4. The most affected pathways were chemokine signaling, Wnt signaling and complement and coagulation cascades, which likely reflects the early stage response of mammary tissue to S. agalactiae infection. No significant gene expression changes were detected by RNA-Seq in the others contrasts. Real time-PCR confirmed the increase in mRNA abundance of immune-related genes: TLR2, TLR4, IL-1ß, and IL-10 at 3 hpi between IQ and NIQ. The expression profiles of Casp1 and Bax for any contrasts were unaffected whereas Bcl2 was increased in IQ, which suggests no induction of apoptosis during the first hours after infection. Results provided novel information regarding the early functional pathways and gene network that orchestrate innate immune responses to S. agalactiae infection. This knowledge could contribute to new strategies to enhance resistance to this disease, such as genomic selection.


Asunto(s)
Perfilación de la Expresión Génica/veterinaria , Glándulas Mamarias Animales/metabolismo , Infecciones Estreptocócicas/veterinaria , Streptococcus agalactiae , Animales , Bovinos , Femenino , Perfilación de la Expresión Génica/métodos , Regulación de la Expresión Génica , Inmunidad/genética , Inflamación/genética , Mastitis Bovina/genética , Mastitis Bovina/inmunología , Mastitis Bovina/microbiología , Reacción en Cadena en Tiempo Real de la Polimerasa/veterinaria , Infecciones Estreptocócicas/genética , Infecciones Estreptocócicas/inmunología
9.
J Biomater Sci Polym Ed ; 30(16): 1489-1504, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31322980

RESUMEN

Cellulose is a renewable polymer quite abundant on the Earth and very attractive for applications in the construction of eco-friendly biomedical products. The aim of this study was to investigate the chemical-physical characteristics of cotton cellulose nanofiber (CCN)/chitosan nanocomposite and its cytocompatibility with human embryonic kidney cells. First, the chemical composition, swelling ratio and surface topography of the nanocomposite were evaluated. Cytocompatibility was then assessed through spreading, proliferation and viability of cells. The experimental results showed that the CCN was an effective nanomaterial agent for increasing the roughness surface of chitosan film. Cell proliferation and changes in cell morphology indicated that the nanocomposite led to improved cell spreading and growth. Cell viability did not decrease after 24 h. However, the cell survival on the nanocomposite was affected at 72 h. The results indicate that CCN/chitosan nanocomposite could be a promising biocompatible biomaterial for biomedical applications.


Asunto(s)
Materiales Biocompatibles/efectos adversos , Materiales Biocompatibles/química , Quitosano/química , Nanocompuestos/efectos adversos , Nanocompuestos/química , Nanofibras/efectos adversos , Nanofibras/química , Línea Celular , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Humanos , Nanoestructuras/química , Polímeros/química , Propiedades de Superficie
10.
Biomed Mater ; 14(3): 035011, 2019 04 02.
Artículo en Inglés | MEDLINE | ID: mdl-30802890

RESUMEN

Nanomaterials can mimic properties of extracellular matrix molecules, promising great potential for scaffold composition in tissue engineering. In the present study, we investigated whether barium titanate nanoparticles (BT NP) combined with alginate polymer would provide a new cytocompatible three-dimensional (3D) scaffold to induce osteogenic stem cell differentiation. In vitro cytocompatibility and osteogenic differentiation potential were investigated using human mesenchymal stem cells (MSC). Firstly, we studied the cell viability and oxidative stress by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) thiazolyl blue tetrazolium bromide (MTT) and superoxide dismutase (SOD) assays. Overall, neither pure BT NP or BT NP/alginate 3D scaffold induced cytotoxicity. The scanning electron and atomic force microscopy revealed that BT NP/alginate 3D scaffold produced exhibited highly interconnected pores and surface nanotopography that were favorable for MSC differentiation. Von Kossa staining showed mineralization nodules and MSCs morphology changed from spindle to cuboid shape after 21 d. Finally, BMP-2 and ALP mRNA were significantly upregulated on cells grown into the BT NP/alginate 3D scaffold. Thus, the BT NP/alginate 3D scaffold showed an osteogenic differentiation induction potential, without the addition of osteogenic supplements. These results indicate that the BT NP/alginate 3D scaffold provides a cytocompatible and bioactive microenvironment for osteogenic human MSC differentiation.


Asunto(s)
Alginatos/química , Compuestos de Bario/química , Nanopartículas del Metal/química , Células Madre/citología , Andamios del Tejido/química , Titanio/química , Diferenciación Celular , Proliferación Celular , Supervivencia Celular , Células Cultivadas , Humanos , Ensayo de Materiales , Células Madre Mesenquimatosas/citología , Microscopía Electrónica de Rastreo , Osteogénesis , Estrés Oxidativo , Polímeros/química , Espectrometría Raman , Ingeniería de Tejidos/métodos
11.
Microbiologyopen ; 8(5): e00736, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30298561

RESUMEN

The aims of this study were to determine the antimicrobial susceptibility profile and genetic diversity of Staphylococcus spp. isolated from dairy cows in Minas Gerais, Brazil, and to assess the relationship among the isolates' susceptibility profiles and pulsed-field gel electrophoresis (PFGE) genotypes. Seventy-nine isolates were used, including S. aureus (n = 71) and coagulase-negative staphylococci (CoNS) (n = 8). Susceptibility to 12 antimicrobial agents was performed. All Staphylococcus spp. were subjected to PFGE. Staphylococcus aureus and CoNS isolates exhibited full susceptibility only to cephalothin. The greatest percentages of resistance among Staphylococcus spp. were observed to penicillins, folate pathway inhibitors, and tetracyclines. Twelve S. aureus and four CoNS were classified as multidrug resistance strains. Percentage of MRSA was also higher among CoNS (75%), compared to S. aureus isolates (2.81%). Adopting 100% of similarity, 34 different genotypes were identified. Association of minimum-spanning tree (MST) analysis with data from municipalities, herds, methicillin-resistant S. aureus (MRSA), and resistance patterns for all isolates did not show any clustering. However, a clustering pattern of bacterial species was observed. Results from this study indicate a high frequency of antimicrobial resistance, especially among CoNS, and a high genetic diversity among Staphylococcus spp. isolated from dairy cows with mastitis in Minas Gerais, Brazil.


Asunto(s)
Farmacorresistencia Bacteriana , Variación Genética , Mastitis Bovina/microbiología , Infecciones Estafilocócicas/veterinaria , Staphylococcus/clasificación , Staphylococcus/efectos de los fármacos , Animales , Antibacterianos/farmacología , Brasil , Bovinos , Electroforesis en Gel de Campo Pulsado , Granjas , Genotipo , Técnicas de Genotipaje , Pruebas de Sensibilidad Microbiana , Infecciones Estafilocócicas/microbiología , Staphylococcus/genética , Staphylococcus/aislamiento & purificación
12.
Pesqui. vet. bras ; 38(4): 579-585, abr. 2018. tab
Artículo en Inglés | LILACS, VETINDEX | ID: biblio-955385

RESUMEN

Coagulase-negative Staphylococcus spp. (CNS) are the main microorganisms involved in ovine mastitis. Treatment at the end of lactation can contribute towards cure and prevention of subclinical cases during the subsequent lactation. However, virulence factors and resistance mechanisms presented by CNS can decrease cure rates. The aims of the study were to identify the species of CNS in milk of mastitic ewes with and without antimicrobial treatment, and to investigate the presence of genes relating to resistance of β-lactam antimicrobials, formation of biofilms, production of enterotoxins and production of the toxic shock syndrome toxin. Cases of failure in the treatment were related with the presence/absence of the respective genes. Sixty sheep were divided into three groups: G1, without treatment; G2, animals treated via the intramammary route with 100mg of cloxacillin during drying off; and G3, sheep treated via the intramammary route with 50 mg of nanoparticulate cloxacillin. Milk samples were gathered during drying off and 15 and 30 days after the parturition of the subsequent lactation. The analyses to identify the species of CNS were carried out by means of the internal transcribe spacer technique and the investigation of the genes responsible for the virulence factors and resistance to oxacillin was performed using the polymerase chain reaction (PCR) technique. No sample was positive for the mecA gene. The only gene relating to production of enterotoxins was sec. Among the genes relating to production of biofilm, icaD was the only one identified in the three experimental groups. Staphylococcus warneri was the main species of CNS isolated during the pre and post-partum periods of the sheep. The species carrying genes relating to production of enterotoxins and biofilms were present in uncured sheep.(AU)


Staphylococus spp. coagulase-negativos (SCN) estão entre os principais micro-organismos envolvidos na mastite ovina. O tratamento ao final da lactação pode contribuir com a cura e a prevenção de casos subclínicos durante a lactação seguinte. Todavia, fatores de virulência e mecanismos de resistência apresentados por SCN podem reduzir as taxas de cura. Os objetivos desse estudo foram identificar as espécies de SCN no leite de ovelhas com mastite com e sem tratamento antimicrobiano e investigar a presença de genes relacionados com resistência a antibióticos beta lactâmicos, formação de biofilmes, produção de enterotoxinas e produção da toxina da síndrome do choque tóxico. Casos de falhas no tratamento foram relacionados com a presença/ausência dos respectivos genes. Sessenta ovelhas foram divididas em três grupos: G1, sem tratamento; G2, animais tratados via intramamária com 100mg de cloxacilina antes da secagem; e G3, ovelhas tratadas via intramamária com 50 mg de cloxacilina nanoparticulada. Amostras de leite foram obtidas durante a secagem e 15 e 30 dias depois do parto na lactação seguinte. As análises para identificar as espécies de SCN foram conduzidas por meio da técnica de Internal transcribe spacer e a investigação dos genes responsáveis pelos fatores de virulência e resistência à oxacilina foi realizada usando a técnica reação em cadeia da polimerase. Nenhuma amostra foi positiva para o gene mecA. O único gene relacionado com a produção de enterotoxinas foi o sec. Dentre os genes relacionados com a produção de biofilme, icaD foi o único identificado nos três grupos experimentais. Staphylococcus warneri foi a principal espécie de SCN isolada durante o pré e pós-parto. As espécies que apresentaram genes relacionados com a produção de enterotoxinas e biofilmes estavam presentes nas ovelhas não curadas.(AU)


Asunto(s)
Animales , Staphylococcus/genética , Ovinos/microbiología , Mastitis Bovina/microbiología
13.
Arch Environ Contam Toxicol ; 73(4): 649-658, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28687867

RESUMEN

Multi-walled carbon nanotubes (MWCNTs) have potential applications in the industrial, agricultural, pharmaceutical, medical, and environmental remediation fields. However, many uncertainties exist regarding the environmental implications of engineered nanomaterials. This study examined the effect of the MWCNTs on metabolic status and morphology of filamentous green microalgae Klebsormidium flaccidum. Appropriate concentrations of MWCNT (1, 50, and 100 µg mL-1) were added to a microalgal culture in the exponential growth phase and incubated for 24, 48, 72, and 96 h. Exposure to MWCNT led to reductions in algal growth after 48 h and decreased on cell viability for all experimental endpoints except for 1 µg mL-1 at 24 h and 100 µg mL-1 after 72 h. At 100 µg mL-1, MWCNTs induced reactive oxygen species (ROS) production and had an effect on intracellular adenosine triphosphate (ATP) content depending on concentration and time. No photosynthetic activity variation was observed. Observations by scanning transmission electron microscopy showed cell damage. In conclusion, we have demonstrated that exposure to MWCNTs affects cell metabolism and microalgal cell morphology. To our best knowledge, this is the first case in which MWCNTs exhibit adverse effects on filamentous green microalgae K. flaccidum. These results contribute to elucidate the mechanism of MWCNT nanotoxicity in the bioindicator organism of terrestrial and freshwater habitats.


Asunto(s)
Microalgas/fisiología , Nanotubos de Carbono/toxicidad , Contaminantes Químicos del Agua/toxicidad , Supervivencia Celular/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo
14.
Sci Rep ; 6: 33588, 2016 09 19.
Artículo en Inglés | MEDLINE | ID: mdl-27642034

RESUMEN

The pellucid zone (PZ) is a protective embryonic cells barrier against chemical, physical or biological substances. This put, usual transfection methods are not efficient for mammal oocytes and embryos as they are exclusively for somatic cells. Carbon nanotubes have emerged as a new method for gene delivery, and they can be an alternative for embryos transfection, however its ability to cross the PZ and mediated gene transfer is unknown. Our data confirm that multiwall carbon nanotubes (MWNTs) can cross the PZ and delivery of pDNA into in vitro-fertilized bovine embryos. The degeneration rate and the expression of genes associated to cell viability were not affected in embryos exposed to MWNTs. Those embryos, however, had lower cell number and higher apoptotic cell index, but this did not impair the embryonic development. This study shows the potential utility of the MWNT for the development of new method for delivery of DNA into bovine embryos.


Asunto(s)
Blastocisto/metabolismo , ADN/administración & dosificación , Técnicas de Transferencia de Gen , Nanotubos de Carbono , Animales , Bovinos , Técnicas de Cultivo de Célula , Células Cultivadas , Femenino , Genes Reporteros , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestructura , Técnicas de Transferencia Nuclear , Plásmidos/administración & dosificación , Plásmidos/genética , Embarazo
15.
Nanomedicine ; 12(5): 1151-9, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-26949162

RESUMEN

Currently there is a growing interest in the use of nanotechnology in reproductive medicine and reproductive biology. However, their toxic effects on mammalian embryos remain poorly understood. In this work, we evaluate the biocompatibility of two fibrous nanomaterials (NMs): cotton cellulose nanofibers (CNF) and carboxylated multiwalled carbon nanotubes (MWCNT-COOH), by performing an investigation of the embryonic development, gene expression (biomarkers focused on cell stress, apoptosis and totipotency) and in situ apoptosis in bovine embryos. Exposure to NMs did not interfere in preimplantation development or in the incidence of apoptosis in the bovine embryo, but they did affect the gene expression. The results presented are important for an understanding of the toxicity of cotton CNF and MWCNT-COOH on mammalian embryos. To our knowledge, we report the first evaluation of biocompatibility between these NMs on preimplantation embryos, which may open a new window for reproductive biomedical applications.


Asunto(s)
Nanoestructuras , Nanotubos de Carbono/toxicidad , Animales , Bovinos , Embrión de Mamíferos , Ensayo de Materiales , Nanofibras , Nanotecnología
16.
Ecotoxicol Environ Saf ; 122: 399-405, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26363983

RESUMEN

Recently, cellulose nanofibers (CNFs) have attracted considerable attention as natural, abundant polymers with excellent mechanical properties and biodegradability. CNFs provide a new materials platform for the sustainable production of high-performance nano-enable products for various applications. Given the increasing rates of CNF production, the potential for their release to the environment and the subsequent impact on ecosystem is becoming an increasing concern that needs to be addressed. Here, we used the Klebsormidium flaccidum as a bioindicator organism of terrestrial and freshwater habitats pollution using a battery of biomarkers. Our results show that cotton CNFs inhibit the proliferation of algae and induce morphological changes in them. The two main toxicity mechanisms induced by cotton CNFs are: (i) a direct contact of CNFs with the cell wall and cellular membrane and (ii) an indirect effect through the generation of reactive oxygen species (ROS).


Asunto(s)
Celulosa/toxicidad , Chlorophyta/efectos de los fármacos , Agua Dulce/química , Gossypium/química , Nanofibras/toxicidad , Contaminantes Químicos del Agua/toxicidad , Celulosa/química , Chlorophyta/metabolismo , Ecosistema , Monitoreo del Ambiente/métodos , Microscopía Electrónica de Transmisión , Nanofibras/química , Tamaño de la Partícula , Especies Reactivas de Oxígeno/metabolismo , Propiedades de Superficie , Contaminantes Químicos del Agua/química
17.
PLoS One ; 10(8): e0136865, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26317399

RESUMEN

This study aimed to evaluate protection induced by the vaccine candidate B. ovis ΔabcBA against experimental challenge with wild type B. ovis in rams. Rams were subcutaneously immunized with B. ovis ΔabcBA encapsulated with sterile alginate or with the non encapsulated vaccine strain. Serum, urine, and semen samples were collected during two months after immunization. The rams were then challenged with wild type B. ovis (ATCC25840), and the results were compared to non immunized and experimentally challenged rams. Immunization, particularly with encapsulated B. ovis ΔabcBA, prevented infection, secretion of wild type B. ovis in the semen and urine, shedding of neutrophils in the semen, and the development of clinical changes, gross and microscopic lesions induced by the wild type B. ovis reference strain. Collectively, our data indicates that the B. ovis ΔabcBA strain is an exceptionally good vaccine strain for preventing brucellosis caused by B. ovis infection in rams.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/deficiencia , Vacuna contra la Brucelosis/administración & dosificación , Brucella ovis/inmunología , Brucelosis/veterinaria , Enfermedades de las Ovejas/prevención & control , Alginatos/química , Animales , Proteínas Bacterianas/genética , Sangre/microbiología , Vacuna contra la Brucelosis/genética , Vacuna contra la Brucelosis/farmacología , Brucella ovis/genética , Brucella ovis/metabolismo , Brucelosis/inmunología , Brucelosis/microbiología , Brucelosis/prevención & control , Cápsulas/administración & dosificación , Cápsulas/farmacología , Ácido Glucurónico/química , Ácidos Hexurónicos/química , Inyecciones Subcutáneas , Masculino , Semen/microbiología , Ovinos , Enfermedades de las Ovejas/inmunología , Enfermedades de las Ovejas/microbiología , Oveja Doméstica , Orina/microbiología
18.
Clin Vaccine Immunol ; 22(7): 789-97, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25947146

RESUMEN

This study aimed to evaluate the Brucella ovis ΔabcBA strain as a vaccine candidate in the murine model. BALB/c mice were subcutaneously or intraperitoneally immunized with a single dose or three doses of the B. ovis ΔabcBA strain and then were challenged with wild-type B. ovis. Single or multiple immunizations provided only mild protection, with significantly smaller numbers of wild-type B. ovis CFU in the livers of immunized mice but not in the spleens. Encapsulation of B. ovis ΔabcBA significantly improved protection against experimental challenges in both BALB/c and C57BL/6 mice. Furthermore, immunization with encapsulated B. ovis ΔabcBA markedly prevented lesions in the spleens and livers of experimentally challenged mice. These results demonstrated that the encapsulated B. ovis ΔabcBA strain confers protection to mice; therefore, this strain has potential as a vaccine candidate for rams.


Asunto(s)
Vacuna contra la Brucelosis/inmunología , Brucella ovis/inmunología , Brucelosis/prevención & control , Vacunación/métodos , Animales , Carga Bacteriana , Vacuna contra la Brucelosis/administración & dosificación , Vacuna contra la Brucelosis/genética , Brucella ovis/genética , Brucelosis/inmunología , Brucelosis/microbiología , Brucelosis/patología , Células Inmovilizadas/inmunología , Modelos Animales de Enfermedad , Portadores de Fármacos/administración & dosificación , Eliminación de Gen , Inyecciones Intraperitoneales , Inyecciones Subcutáneas , Hígado/microbiología , Hígado/patología , Masculino , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Bazo/microbiología , Bazo/patología , Vacunas Atenuadas/administración & dosificación , Vacunas Atenuadas/genética , Vacunas Atenuadas/inmunología
19.
Ecotoxicology ; 24(4): 938-48, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25763523

RESUMEN

Studies have been demonstrating that smaller particles can lead to unexpected and diverse ecotoxicological effects when compared to those caused by the bulk material. In this study, the chemical composition, size and shape, state of dispersion, and surface's charge, area and physicochemistry of micro (BT MP) and nano barium titanate (BT NP) were determined. Green algae Chlorella vulgaris grown in Bold's Basal (BB) medium or Seine River water (SRW) was used as biological indicator to assess their aquatic toxicology. Responses such as growth inhibition, cell viability, superoxide dismutase (SOD) activity, adenosine-5-triphosphate (ATP) content and photosynthetic activity were evaluated. Tetragonal BT (~170 nm, 3.24 m(2) g(-1) surface area) and cubic BT (~60 nm, 16.60 m(2) g(-1)) particles were negative, poorly dispersed, and readily aggregated. BT has a statistically significant effect on C. vulgaris growth since the lower concentration tested (1 ppm), what seems to be mediated by induced oxidative stress caused by the particles (increased SOD activity and decreased photosynthetic efficiency and intracellular ATP content). The toxic effects were more pronounced when the algae was grown in SRW. Size does not seem to be an issue influencing the toxicity in BT particles toxicity since micro- and nano-particles produced significant effects on algae growth.


Asunto(s)
Compuestos de Bario/toxicidad , Chlorella vulgaris/efectos de los fármacos , Chlorella vulgaris/fisiología , Nanopartículas del Metal/toxicidad , Titanio/toxicidad , Contaminantes Químicos del Agua/toxicidad , Francia
20.
Pesqui. vet. bras ; 34(9): 865-868, set. 2014. tab
Artículo en Inglés | LILACS | ID: lil-728824

RESUMEN

Epidemiological and health aspects of sheep husbandry were assessed on 213 sheep flocks in 142 municipalities from the state of Minas Gerais, southeastern Brazil. An updated questionnaire was filled out for each flock, requesting data on the farm, the flock and the farmer by the veterinarians of the State Government Agency for Animal Health (Instituto Mineiro de Agropecuária). Thirteen important variables were selected and scored to determine the technological level of the 117 farms; 0.9% of them was classified as high technological level, 45.3% as medium technological level and 53.0% as low technological level. Lamb production was the main objective of the farms and the main features were low-frequencies of individual identification of animals (16.9%), technical assistance (31.9%), use of quarantine for newly acquired animals (0.9%) the separation of animals by age group (3.7%) and requeste the sanitary certificate at purchasing of animals (11.7%). The main health problems reported were abortion (23.9%), keratoconjunctivitis (17.9%), contagious ecthyma (13.6%), pneumonia (10.3%), diarrhea (9.3%) and caseous lymphadenitis (6.1%). Information of the epidemiological situation and the mainly health measures used in the sheep farms are important to improve the productivity and quality of the lamb...


Os aspectos epidemiológicos e sanitários da ovinocultura foram levantados em 213 rebanhos ovinos em 142 municípios do estado de Minas Gerais, sudeste do Brasil. Um questionário atualizado foi preenchido para cada rebanho, com informações sobre a fazenda, o rebanho e do fazendeiro, por veterinários do Instituto Mineiro de Agropecuária. Treze variáveis importantes foram selecionadas e pontuadas para determinar o nível tecnológico em 117 fazendas; 0,9% foram classificadas como de alto nível tecnológico, 45,3% como de médio nível tecnológico e 53,0% como de baixo nível tecnológico. A produção de carne de cordeiro foi o principal objetivo das fazendas amostradas e as principais características foram baixa frequência de identificação individual dos animais (16,9%), assistência técnica (31,9%), uso de quarentena para os animais recém-adquiridos (0,9%), separação de animais por faixa etária (3.7%) e solicitação de certificados sanitários na compra de animais (11,7%). Os principais problemas sanitários relatados foram o aborto (23,9%), ceratoconjuntivite (17,9%), ectima contagioso (13,6%), pneumonia (10,3%), diarreia (9,3%) e linfadenite caseosa (6,1%). Informações sobre a situação epidemiológica e das principais medidas sanitárias utilizadas nas propriedades com ovinos são importantes para melhorar produtividade e a qualidade da carne ovina...


Asunto(s)
Animales , Masculino , Femenino , Apareamiento , Enfermedades Virales de Transmisión Sexual/epidemiología , Enfermedades Virales de Transmisión Sexual/prevención & control , Ovinos , Cuarentena/veterinaria , Perfiles Sanitarios
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