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1.
Fungal Biol ; 124(12): 1039-1051, 2020 12.
Article in English | MEDLINE | ID: mdl-33213784

ABSTRACT

The fungal pathogen Sporisorium scitamineum causes sugarcane smut disease. We have previously shown that resistant sugarcane plants induce ROS, coinciding with a delay in fungal colonization. Here, we investigated whether the fungus modifies the enzymatic antioxidant system in vitro and when colonizing sugarcane tissues in response to ROS. In vitro, the exposure to ROS did not affect cell integrity, and a combination of superoxide dismutases (SOD) and catalases (CAT) were active. In vitro, the fungus did not alter the expression of the transcriptional regulator Yap1 and the effector Pep1. The fungus activated distinct enzymes when colonizing plant tissues. Instead of CAT, S. scitamineum induced glutathione peroxidase (Gpx) expression only when colonizing smut-resistant plants. Yap1 had an earlier expression in both smut-susceptible and -resistant plants, with no apparent correlation with the expression of antioxidant genes sod, cat, gpx, or external redox imbalance. The expression of the effector pep1 was induced only in smut-resistant plants, potentially in response to ROS. These results collectively suggest that S. scitamineum copes with oxidative stress by inducing different mechanisms depending on the conditions (in vitro/in planta) and intensity of ROS. Moreover, the effector Pep1 is responsive to the stress imposed only by the sugarcane resistant genotype.


Subject(s)
Basidiomycota , Plant Diseases/microbiology , Reactive Oxygen Species , Saccharum , Basidiomycota/enzymology , Basidiomycota/genetics , Gene Expression Regulation, Plant , Reactive Oxygen Species/metabolism , Saccharum/microbiology
2.
Science ; 370(6514)2020 10 16.
Article in English | MEDLINE | ID: mdl-33060332

ABSTRACT

The microscopic environment inside a metazoan organism is highly crowded. Whether individual cells can tailor their behavior to the limited space remains unclear. In this study, we found that cells measure the degree of spatial confinement by using their largest and stiffest organelle, the nucleus. Cell confinement below a resting nucleus size deforms the nucleus, which expands and stretches its envelope. This activates signaling to the actomyosin cortex via nuclear envelope stretch-sensitive proteins, up-regulating cell contractility. We established that the tailored contractile response constitutes a nuclear ruler-based signaling pathway involved in migratory cell behaviors. Cells rely on the nuclear ruler to modulate the motive force that enables their passage through restrictive pores in complex three-dimensional environments, a process relevant to cancer cell invasion, immune responses, and embryonic development.


Subject(s)
Mechanotransduction, Cellular , Nuclear Envelope/physiology , Actomyosin/metabolism , Animals , Cell Movement , Embryonic Development , HeLa Cells , Humans , Mice , Myosin Heavy Chains/metabolism , Neoplasm Invasiveness , Neoplasms/pathology
3.
J Eur Acad Dermatol Venereol ; 34(10): 2409-2413, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32421881

ABSTRACT

BACKGROUND: Frontal fibrosing alopecia (FFA) is a lymphocytic scarring alopecia whose worldwide incidence is rising. Environmental triggers combined with genetic predisposition represent one of the current hypotheses in FFA aetiology. Familial clusters are opportunities to investigate the genetic basis of diseases. OBJECTIVES: Assess human leucocyte antigen (HLA) genetic variability in a Brazilian sample of a large familial cluster (six sisters and one daughter) with FFA, unnafected familiar members and sporadic cases of FFA. METHODS: We addressed the HLA-A, HLA-B, HLA-C, HLA-G and HLA-E genetic variability in this family and in seven sporadic FFA cases, comparing allele frequencies with those reported for the São Paulo State from Brazil. RESULTS: Two susceptibility haplotypes, C*17:01:01:02/B*42:01:01:01 and C*07:02:01:03/B*07:02:01:01, were identified among familial cases and also in sporadic cases. The first haplotype is rare among Brazilians, and it was not previously reported as being associated with FFA. Both alleles were found in some different unaffected familiars, what emphasizes the role of environmental triggers in disease development. HLA-A, HLA-G and HLA-E genes were not associated to familiar nor FFA sporadic cases. CONCLUSION: The identification of susceptibility haplotypes in FFA reinforces the genetic predisposition to the disease.


Subject(s)
Alopecia , Lichen Planus , Alleles , Alopecia/genetics , Brazil , Genetic Predisposition to Disease , Haplotypes , Histocompatibility Antigens Class II , Humans
4.
Arch Ital Biol ; 157(4): 105-110, 2019 Dec 01.
Article in English | MEDLINE | ID: mdl-32323294

ABSTRACT

Parkinson's disease is a neurodegenerative disease with manifestations related to oxidative stress and damage to the skeletal striated musculature. This study evaluated the electromyographic fatigue of the masseter and temporal muscles in individuals with Parkinson's disease. The median frequency of the normotensive electromyographic signal was analyzed in 16 individuals, aged between 50 and 70 years, with Parkinson's disease in stages I and III of the Hoehn and Yahr disability scale (n=8) or without the disease (n=8). The data were tabulated and analyzed statistically (t-test, p .05). Compared with the group without Parkinson's disease, the group with the disease showed an increase in the median frequency, with significant differences for the right masseter (p=.05) and the right temporal (p=.03) muscles. The results suggest that there is a link between Parkinson's disease and functional alterations of the masticatory system, especially when electromyographic fatigue is assessed.


Subject(s)
Electromyography , Masseter Muscle , Muscle Fatigue , Parkinson Disease , Temporal Muscle , Aged , Case-Control Studies , Humans , Masseter Muscle/pathology , Middle Aged , Parkinson Disease/complications , Parkinson Disease/pathology , Temporal Muscle/pathology
7.
Genet Mol Res ; 16(3)2017 Sep 27.
Article in English | MEDLINE | ID: mdl-28973772

ABSTRACT

In order to obtain the certificate of cultivar protection, it is necessary to prove its distinctiveness, homogeneity, and stability. Currently, there are 37 descriptors for differentiating soybeans cultivars. However, they are still not enough and, as a result, it is necessary to create, identify, and evaluate new descriptors. This study was aimed at evaluating the genotypic and environment interaction (GxE) and determining the stability of eight soybean cultivars for five vegetative-stage descriptors. The research was done in a greenhouse of the Soybean Breeding and Genetic Studies Program of Universidade Federal de Uberlândia. The treatments were composed of eight soybean cultivars, sown in two different growing seasons (January 25, 2014 and November 27, 2014). The experiments were carried out in randomized complete blocks with three replications and each experimental plot consisted of one pot with four soybean plants. The characters evaluated were: length of hypocotyl (LH), length of epicotyl (LE), length of unifoliolate leaf petiole (LUP), length of first trifoliate leaf petiole (LTLP), and rachis length of terminal leaflet of the first trifoliate leaf (RL). The data achieved from the trials were undergone genetic-statistical analyses by the GENES software. For all analyzed characters, the existence of genetic variability was observed emphasizing the vegetative-stage descriptors' utility to differentiate soybean cultivars. The occurrence of GxE interaction was detected for all characters assessed, mainly of complex nature, except by RL, which was of simple nature. The most stable cultivars for the vegetative-stage descriptors analysed were UFUS 7415 and UFUS Impacta.


Subject(s)
Gene-Environment Interaction , Glycine max/genetics , Plant Breeding/methods , Quantitative Trait, Heritable , Genetic Variation , Genomic Instability , Hypocotyl/genetics , Hypocotyl/growth & development , Models, Genetic , Plant Leaves/genetics , Plant Leaves/growth & development , Selective Breeding , Glycine max/growth & development
8.
Mater Sci Eng C Mater Biol Appl ; 78: 341-348, 2017 Sep 01.
Article in English | MEDLINE | ID: mdl-28575993

ABSTRACT

Graphene oxide nanoribbons (O-GNR) surges as an interesting nanomaterial for biomedical applications due to feasibility to incorporate functional groups and possible bactericidal properties. Herein, high concentrations of O-GNR were biologically evaluated using human osteoblast cells and gram positive and negative bacteria. Briefly, our goal were to evaluate: (1) synthetic pathway, (2) characterization and (3) effects of O-GNR composition and structural factors as a new approach for biomedical applications. For this, O-GNR were produced combining chemical vapor deposition and oxygen plasma treatment of multiwalled carbon nanotubes. Then, we analyzed the bioactivity, cell viability, osteogenic differentiation, matrix mineralization, mRNA levels of the five genes related direct to bone repair and bactericidal effect of high concentrations of O-GNR (10µgmL-1, 100µgmL-1, 200µgmL-1 and 300µgmL-1). Impressively, O-GNR showed no cytotoxic effects up to a concentration of 100µgmL-1 and no gene expression alteration when used in its dose. We also observed that S. aureus and E. coli bacteria are susceptible to damage when incubated with 100µgmL-1 of O-GNR, showing approximately 50% of bacterial death. We consider that O-GNR displays attractive properties when used at a suitable dose, displaying bactericidal effect and apparently lacking to cause damages in the bone repair process.


Subject(s)
Nanotubes, Carbon , Bone Regeneration , Escherichia coli , Graphite , Humans , Nanostructures , Osteogenesis , Oxides , Staphylococcus aureus
9.
Photodiagnosis Photodyn Ther ; 18: 193-197, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28238893

ABSTRACT

Photodynamic therapy (PDT) is a modality of therapy that involves the activation of photosensitive substances and the generation of cytotoxic oxygen species and free radicals to promote the selective destruction of target tissues. This study analyzed the application of PDT to Tritrichomonas foetus, a scourged and etiological agent of bovine trichomoniasis, a sexually transmitted infectious disease. As it is an amitochondrial and aerotolerant protozoan, it produces energy under low O2 tension via hydrogenosome. T. foetus from an axenic culture was incubated with photosensitizer tetrasulfonated aluminium phthalocyanine and then irradiated with a laser source (InGaAIP) at a density of 4.5Jcm-2. The DNA integrity of the control and treated group parasites was analyzed by conventional gel electrophoresis and comet assay techniques. In previous results, morphological changes characterized by apoptotic cell death were observed after T. foetus was submitted to PDT treatment. In the treated groups, T. foetus DNA showed a higher concentration of small fragments, about 200pb, in gel electrophoresis after PDT. In the comet assay, the DNA tail percentage was significantly higher in the treated groups. These results demonstrate that PDT leads to DNA fragmentation with changes in nuclear morphology and apoptotic features.


Subject(s)
Cattle/parasitology , DNA Damage/genetics , DNA, Protozoan/genetics , DNA, Protozoan/radiation effects , Photochemotherapy/methods , Tritrichomonas foetus/drug effects , Tritrichomonas foetus/genetics , Animals , DNA, Protozoan/drug effects , Dose-Response Relationship, Drug , Dose-Response Relationship, Radiation , Radiation Dosage , Tritrichomonas foetus/radiation effects
10.
J Econ Entomol ; 110(1): 111-117, 2017 02 01.
Article in English | MEDLINE | ID: mdl-28053209

ABSTRACT

In many sugarcane plantations in Brazil, the straw is left on the soil after harvesting, and vinasse, a by-product of the production of sugar and ethanol, is used for fertigation. Our goal was to compare ant community composition and species richness in the straw mulch of sugarcane crops with the leaf litter of neighboring forests. We tested the hypothesis that ant communities in the straw mulch of vinasse-irrigated sugarcane crops and in the forest leaf litter were similar, because the combination of straw mulching and vinasse irrigation has a positive effect on soil fauna. Straw mulch and leaf litter were collected from 21 sites and placed in Berlese funnels. In total, 61 species were found in the forest leaf litter, whereas 34 and 28 species were found in the straw mulch of sugarcane fields with and without vinasse, respectively. Ant communities differed between forest and crop fields, but the species in the sugarcane straw mulch were a subset of the species found in the forest leaf litter. Although vinasse is rich in organic matter, it did not increase ant diversity. Seven feeding and/or foraging types were identified and, among the different types, surface-foraging omnivorous ants were the most prevalent in all habitats. Vinasse-irrigated sugarcane straw mulch had more predatory species than mulch from vinasse-free fields, but fewer than forest leaf litter. However, this positive effect of vinasse irrigation should be carefully evaluated because vinasse has negative effects on the environment.


Subject(s)
Ants/physiology , Biodiversity , Forests , Saccharum , Soil , Animals , Brazil , Plant Leaves , Saccharum/growth & development
11.
Gene Ther ; 22(1): 65-75, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25231172

ABSTRACT

In our earlier studies, Semliki Forest virus vector VA7 completely eliminated type I interferon (IFN-I)-unresponsive human U87-luc glioma xenografts, whereas interferon-responsive mouse gliomas proved refractory. Here, we describe in two clones of CT26 murine colon carcinoma, opposed patterns of IFN-I responsiveness and sensitivity to VA7. Both CT26WT and CT26LacZ clones secreted biologically active interferon in vitro upon virus infection but only CT26WT cells were protected. Focal infection of CT26WT cultures was self-limiting but could be rescued using IFN-I pathway inhibitor Ruxolitinib or antibody against IFNß. Whole transcriptome sequencing (RNA-Seq) and protein expression analysis revealed that CT26WT cells constitutively expressed 56 different genes associated with pattern recognition and IFN-I signaling pathways, spanning two reported anti-RNA virus gene signatures and 22 genes with reported anti-alphaviral activity. Whereas CT26WT tumors were strictly virus-resistant in vivo, infection of CT26LacZ tumors resulted in complete tumor eradication in both immunocompetent and severe combined immune deficient mice. In double-flank transplantation experiments, CT26WT tumors grew despite successful eradication of CT26LacZ tumors from the contralateral flank. Tumor growth progressed uninhibited also when CT26LacZ inoculums contained only a small fraction of CT26WT cells, demonstrating dominance of IFN responsiveness when heterogeneous tumors are targeted with interferon-sensitive oncolytic viruses.


Subject(s)
Colonic Neoplasms/therapy , Oncolytic Virotherapy , Oncolytic Viruses/genetics , Semliki forest virus/genetics , Animals , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Bystander Effect , Cell Line, Tumor , Colonic Neoplasms/immunology , Colonic Neoplasms/pathology , Genetic Vectors , Green Fluorescent Proteins/biosynthesis , Interferon Type I/pharmacology , Interferon Type I/therapeutic use , Interferon-beta/metabolism , Mice, Inbred BALB C , Necrosis , Neoplasm Transplantation , STAT1 Transcription Factor/metabolism , Transfection , Treatment Outcome
12.
Mater Sci Eng C Mater Biol Appl ; 41: 65-9, 2014 Aug 01.
Article in English | MEDLINE | ID: mdl-24907738

ABSTRACT

We report the synthesis and application of novel graphene oxide and carbon nanotube oxide (GCN-O) composite. First, pristine multi-walled carbon nanotube was prepared by chemical vapour deposition furnace and then exfoliated and oxidised simultaneously by oxygen plasma etching. The superficial and volumetric compositions of GCN-O were measured by XPS spectroscopy and EDX spectroscopy, respectively. Both XPS and EDX analyses evidence that the GCN-O is composed of up to 20% of oxygen atoms. As a result, GCN-O forms a stable colloidal aqueous solution and shows to have strong interaction with the cell membrane of Tritrichomonas foetus protozoa, making easy its application as a drug carrier. Trichomoniasis infection of cattle is a devastating disease for cattle producers, causing some damages to females and fetus, and the abortion is the most serious result of this disease. There is no effective treatment for trichomoniasis infection yet. Therefore, new treatment, especially one with no collateral effects in animals, is required. With this goal in mind, our results suggest that water dispersible composite is a novel nanomaterial, promising for Trichomoniasis infection treatment and as therapeutic delivery agent as well.


Subject(s)
Graphite/chemistry , Nanocomposites/chemistry , Nanotubes, Carbon/chemistry , Animals , Antiprotozoal Agents/administration & dosage , Antiprotozoal Agents/chemistry , Antiprotozoal Agents/pharmacology , Cattle , Drug Carriers/chemistry , Female , Nanocomposites/therapeutic use , Prospective Studies , Protozoan Infections/microbiology , Protozoan Infections/therapy , Tritrichomonas foetus/drug effects
13.
Arq. bras. med. vet. zootec ; 66(2): 631-634, Jan.-Apr. 2014.
Article in Portuguese | LILACS | ID: lil-709309

ABSTRACT

This study aimed to report three cases of contagious agalactia (CA) by Mycoplasma agalactiae in goat kids born with polyarthritis. The nanny goats belonging to two different herds presented clinical signs of CA during pregnancy and in parturition they were apparently healthy. The carpal articulations of the three goat kids, the tarsus articulation in one, and thigh-femoral articulation in another showed swelling, pain and impairment of the flexion-extension movements. The articular liquid was collected from two goat kids at birth and revealed a content which varied from transparent to fibrinopurulent, presenting a yellow coloring. The samples were plated on modified Hayflick. The colonies had the appearance of "fried egg" and were confirmed as being M. agalactiae by biochemical tests and 16S rRNA PCR. Blood was collected from three animals soon after birth and submitted to the indirect ELISA test for the determination of the titration of the anti- M. agalactiae antibodies. The results confirmed that the goat kids were infected during pregnancy by M. agalactiae and resulted in the birth of an offspring with clinical signs of CA being immune tolerant...


Subject(s)
Animals , Arthritis/veterinary , Infections/transmission , Mycoplasma agalactiae/isolation & purification , Ruminants , Polymerase Chain Reaction/veterinary , Maternal-Fetal Exchange/immunology
14.
Arq. Inst. Biol ; 80(1): 19-26, jan.-mar.2013.
Article in Portuguese | LILACS, VETINDEX | ID: biblio-1462215

ABSTRACT

A mastite é uma infecção frequente da glândula mamária, sendo a principal doença que afeta o úbere das fêmeas e responsável pelos maiores prejuízos à produção leiteira em caprinos, reduzindo em quantidade e depreciando a qualidade do leite e seus derivados. Nesse estudo foram colhidas amostras de leite de cabras com reação positiva ao CMT, em propriedades localizadas em Bonfim de Feira, Barra do Pojuca, Feira de Santana, Camaçari, Anguera e Antônio Cardoso, todas próximas à Cidade de Salvador, Bahia. Do material coletado foi realizado cultivo bacteriológico em ágar sangue de ovino a 10%, ágar McConkey e também enriquecido em caldo BHI. O Staphylococcus spp. foi a bactéria de maior prevalência (90,3%), seguida de Streptococcus (4,8%), Micrococcus (1,6%) e Enterobacter (1,6%). Todas as bactérias foram submetidas ao teste de sensibilidade aos antimicrobianospelo método de difusão em disco, sendo que 54,1% das estirpes estudadas apresentaram sensibilidade a todas as drogas testadas, e 45,9% das estirpes identificadas apresentaram resistência a pelo menos um dos antimicrobianos. O presente estudo confirmou o Staphylococcus spp. como a principal bactéria envolvida na etiologia das mastites subclínicas caprinas.


Bacteria involved in subclinical mastitis in goats in the region of Salvador, Bahia, Brazil. Mastitis is a common infection of the mammary gland, the main disease affecting the udder of females, and responsible for major losses in milk production in goats, decreasing the quantity and quality of the milk and its derivatives. In this study milk samples were collected from goats with positive reaction to CMT in properties located in Bonfim de Feira, Barra do Pojuca, Feira de Santana, Camaçari, Anguera and Antônio Cardoso, all of which are places surrounding the city of Salvador, Bahia, Brazil. The samples were submitted to bacteriological culture carried out in agar with 10% sheep blood, McConkey agar, and agar enriched with BHI broth. Staphylococcus spp. bacteria was the most prevalent (90.3%), followed by Streptococcus (4.8%), Micrococcus (1.6%) and Enterobacter (1.6%). All bacteria were subjected to antimicrobial susceptibility testing by the disc diffusion method, revealing that 54.1% of the strains studied were sensitive to all drugs tested, while 45.9% of identified strains showed resistance to at least one of antimicrobials. The present studyconfirmed Staphylococcus spp. as the main bacteria involved in the etiology of subclinical goat mastitis.


Subject(s)
Animals , Anti-Bacterial Agents/pharmacology , Mammary Glands, Animal/anatomy & histology , Mastitis/pathology , Goats/classification
15.
J. venom. anim. toxins incl. trop. dis ; 17(4): 496-500, 2011. ilus
Article in English | LILACS | ID: lil-623514

ABSTRACT

The present study reports a snakebite in a horse in the state of Pará, Brazil. At initial evaluation the animal was reluctant to walk and had tachycardia, tachypnea, severe lameness, bleeding on the pastern and swelling around the left hind leg. Blood samples from the bleeding sites, took on the first day, showed leukocytosis and neutrophilia, whereas biochemical values of urea and creatinine were significantly increased. The chosen treatment was snake antivenom, fluid therapy, antibiotics, anti-inflammatory agents and diuretic drugs. On the fourth day of therapy, the hematological values were within normal parameters. There was improvement related to the clinical lameness and swelling of the limb. However, a decrease in water intake and oliguria were observed. On the seventh day the animal died. Necropsy revealed areas of hemorrhagic edema in the left hind limb and ventral abdomen; the kidneys presented equimosis in the capsule, and when cut they were wet. Moreover, the cortex was pale, slightly yellow and the medullary striae had the same aspect. Based on these data, we concluded that the snakebite in the present study was caused by Bothrops spp. and that renal failure contributed to death.


Subject(s)
Animals , Bothrops , Horses , Snake Bites
16.
Arq. Inst. Biol. (Online) ; 77(2): 233-237, abr.-jun. 2010. tab
Article in Portuguese | VETINDEX, LILACS | ID: biblio-1390603

ABSTRACT

A tuberculose é uma enfermidade infecciosa crônica, que afeta mamíferos e aves e constitui um sério problema de saúde pública e animal. Objetivando realizar um levantamento molecular da enfermidade em bovinos abatidos em matadouros frigoríficos no Estado da Bahia, Brasil, foram analisadas as lesões pulmonares e de linfonodos mediastínicos de 43 carcaças de animais abatidos em três matadouros-frigoríficos localizados na Região Metropolitana de Salvador, Bahia. Sete isolados de Mycobacterium bovis foram identificados, através da técnica do spolygotyping, e discriminados em três diferentes espoligotipos (SB1055, SB0120 e SB0268) descritos no Brasil e em diversas áreas do mundo. Os resultados indicam que o método de diagnóstico utilizado pode contribuir para a criação de uma base de dados para o estudo epidemiológico da tuberculose bovina no Estado da Bahia.


Tuberculosis is an infectious chronic disease that affects mammals and birds and constitutes a serious problem for public and animal health. Pulmonary and mediastinic lymph node lesions of 43 animals slaughtered in 3 slaughterhouses in the metropolitan region of the city of Salvador, Bahia, Brazil, were analyzed with the objective of obtaining a molecular survey of the disease in bovines slaughtered in slaughterhouses in the state. Seven isolates ofMycobacterium bovis were identified through the spoligotyping technique and classified into 3 different spoligotypes (SB1055, SB0120, SB0268), described in Brazil and in many areas worldwide. The results indicate that the diagnostic method utilized may contribute to the creation of a database for the epidemiologic study of bovine tuberculosis in the state of Bahia.


Subject(s)
Animals , Cattle , Mycobacterium bovis/isolation & purification , Mycobacterium bovis/genetics , Brazil , Bacterial Typing Techniques/veterinary , Abattoirs
17.
Med Biol Eng Comput ; 48(6): 573-7, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20390460

ABSTRACT

This study analyzes the performance of knee extension and flexion of Taekwondo and Kickboxing athletes. The power values were extracted through electromyography obtained by an isokinetic dynamometer at 60 degrees per second. These values are resulted from the square of the electromyography signal. The analysis of kick power was made using a modified wavelet algorithm considering values with 95% significance. Both groups presented equivalent power and torque capacity with different training times and experience, on the other hand, the wavelet analysis showed better results in muscular recruitment performance in athletes with more experience, in other words, power is not only performance but also power plus recruitment produces better results. This study uniquely showed that muscular enhancement capacity is not only related to the power capacity of contraction but also to motor coordination.


Subject(s)
Knee Joint/physiology , Martial Arts/physiology , Muscle, Skeletal/physiology , Adolescent , Biomechanical Phenomena , Electromyography/methods , Humans , Male , Signal Processing, Computer-Assisted , Young Adult
18.
J Colloid Interface Sci ; 340(1): 87-92, 2009 Dec 01.
Article in English | MEDLINE | ID: mdl-19758597

ABSTRACT

Diamond-like carbon (DLC) films have been the focus of extensive research in recent years due to their potential applications as surface coatings on biomedical devices. Titanium dioxide (TiO2) in the anatase crystalline form is a strong bactericidal agent when exposed to near-UV light. In this work we investigate the bactericidal activity of DLC films containing TiO2 nanoparticles. The films were grown on 316L stainless-steel substrates from a dispersion of TiO2 in hexane using plasma-enhanced chemical vapor deposition. The composition, bonding structure, surface energy, stress, and surface roughness of these films were also evaluated. The antibacterial tests were performed against Escherichia coli (E. coli) and the results were compared to the bacterial adhesion force to the studied surfaces. The presence of TiO2 in DLC bulk was confirmed by Raman spectroscopy. As TiO2 content increased, I(D)/I(G) ratio, hydrogen content, and roughness also increased; the films became more hydrophilic, with higher surface free energy and the interfacial energy of bacteria adhesion decreased. Experimental results show that TiO2 increased DLC bactericidal activity. Pure DLC films were thermodynamically unfavorable to bacterial adhesion. However, the chemical interaction between the E. coli and the studied films increased for the films with higher TiO2 concentration. As TiO2 bactericidal activity starts its action by oxidative damage to the bacteria wall, a decrease in the interfacial energy of bacteria adhesion causes an increase in the chemical interaction between E. coli and the films, which is an additional factor for the increasing bactericidal activity. From these results, DLC with TiO2 nanoparticles can be useful for producing coatings with antibacterial properties.


Subject(s)
Anti-Bacterial Agents/pharmacology , Carbon/pharmacology , Escherichia coli/drug effects , Nanoparticles/chemistry , Titanium/pharmacology , Anti-Bacterial Agents/chemistry , Bacterial Adhesion/drug effects , Carbon/chemistry , Materials Testing , Titanium/chemistry
19.
Parasitology ; 136(10): 1097-105, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19631016

ABSTRACT

Temporal changes in the prevalence of antigenic variants in Plasmodium falciparum populations have been interpreted as evidence of immune-mediated frequency-dependent selection, but evolutively neutral processes may generate similar patterns of serotype replacement. Over 4 years, we investigated the population dynamics of P. falciparum polymorphisms at the community level by using 11 putatively neutral microsatellite markers. Plasmodium falciparum populations were less diverse than sympatric P. vivax isolates, with less multiple-clone infections, lower number of alleles per locus and lower virtual heterozygosity, but both species showed significant multilocus linkage disequilibrium. Evolutively neutral P. falciparum polymorphisms showed a high turnover rate, with few lineages persisting for several months in the population. Similar results had previously been obtained, in the same community, for sympatric P. vivax isolates. In contrast, the prevalence of the 2 dimorphic types of a major antigen, MSP-2, remained remarkably stable throughout the study period. We suggest that the relatively fast turnover of parasite lineages represents the typical population dynamics of neutral polymorphisms in small populations, with clear implications for the detection of frequency-dependent selection of polymorphisms.


Subject(s)
Evolution, Molecular , Genetic Variation , Plasmodium falciparum/genetics , Polymorphism, Genetic , Population Dynamics , Rural Population , Animals , Brazil/epidemiology , Humans , Malaria, Falciparum/epidemiology , Malaria, Falciparum/parasitology , Microsatellite Repeats/genetics , Plasmodium falciparum/classification , Prevalence , Prospective Studies
20.
Stress ; 12(4): 320-7, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19085621

ABSTRACT

The aim of this study was to analyze the effects of chronic mild unpredictable stress (CMS) on the vasoconstrictor response and morphology of the thoracic aorta and serum lipid profiles in rats. Male Sprague-Dawley rats were submitted to CMS, which consisted of the application of different stressors for 7 days per week across 3 weeks. The rats were sacrificed 15 days after CMS exposure. CMS induced supersensitivity to the vasoconstrictor effect of phenylephrine in endothelium-intact thoracic aortic rings without changes in aortic rings without endothelium, or pre-incubated with nitric oxide (NO) synthesis inhibitor. Rats submitted to CMS showed hypertrophy of the intima and tunica media of thoracic aorta, increased serum levels of triglycerides, total cholesterol, very low-density lipoprotein cholesterol, low-density lipoprotein cholesterol and atherogenic index, without changes in high-density lipoprotein cholesterol levels, when compared with control rats. These data indicate that CMS induces physiological and morphological changes that may contribute to the development of atherosclerosis by mechanisms related to deficiency in NO production and dyslipidemia.


Subject(s)
Aorta, Thoracic/drug effects , Atherosclerosis/psychology , Phenylephrine/pharmacology , Stress, Psychological/physiopathology , Vasoconstrictor Agents/pharmacology , Animals , Aorta, Thoracic/enzymology , Aorta, Thoracic/pathology , Atherosclerosis/pathology , Atherosclerosis/physiopathology , Corticosterone/blood , Lipids/blood , Male , Nitric Oxide Synthase/metabolism , Rats , Rats, Sprague-Dawley , Tunica Intima/pathology , Tunica Media/pathology
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