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BACKGROUND: This study aimed to evaluate sociodemographic and clinical factors influencing overall survival (OS) in patients with oral squamous cell carcinoma (OSCC). MATERIAL AND METHODS: Medical charts of 547 patients with OSCC from a public hospital in northeastern Brazil seen between 1999 and 2013 were evaluated. Survival analysis was performed using the Kaplan-Meier method. The influence of age, sex, ethnicity, clinical stage, anatomical location, type of treatment, and comorbidities on the patients' prognosis was evaluated. Cox proportional hazards regression model was used to identify independent prognostic factors. RESULTS: The 5-year OS was 39%. Multivariate analysis showed that age < 40 years (HR = 2.20; 95%CI: 1.02-4.72) and a single treatment modality (HR = 1.91; 95%CI: 1.37-2.67) were associated with a poor prognosis, while early clinical stage resulted in better outcomes (HR = 0.38; 95%CI: 0.25-0.58). CONCLUSIONS: OSCC patients in advanced clinical stages, diagnosed at a younger age, and submitted to a single therapeutic modality have a poorer prognosis.
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Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Bucais , Adulto , Brasil , Carcinoma de Células Escamosas/terapia , Humanos , Neoplasias Bucais/terapia , Prognóstico , Estudos Retrospectivos , Carcinoma de Células Escamosas de Cabeça e PescoçoRESUMO
AIM: To evaluate factors associated with difficulty eating and speaking due to oral problems according to the reports of children. METHODS: A cross-sectional study was conducted with 769 5-year-old children at preschools in a city in northeast Brazil. Parents/caretakers answered a questionnaire addressing socio-demographic data and a history of dental pain. The children answered the scale of oral health outcomes for 5-year-old children, which was used to evaluate the dependent variables. Clinical examinations of the children were performed by examiners who had undergone calibration exercises. Data analysis involved descriptive statistics and Poisson regression analysis (α = 5%). RESULTS: The prevalence of the perception of functional limitations on the part of the children was 35.5% for difficulty eating and 22.9% for difficulty speaking. Difficulty eating was associated with a history of dental pain (PR = 1.68; 95% CI 1.27-2.22) and the occurrence of traumatic dental injury (TDI) (PR = 1.23; 95% CI 1.01-1.52). Difficulty speaking due to oral problems was associated with studying at a public preschool (PR = 1.71; 95% CI 1.19-2.46), a history of dental pain (PR = 1.54; 95% CI 1.07-2.20), and the occurrence of TDI (PR = 1.52; 95% CI 1.12-2.06). CONCLUSIONS: Pain symptoms and the occurrence of TDI can exert an influence on the development of functional limitations. With regard to socioeconomic factors, studying at a public preschool can influence difficulty speaking in children.
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Cárie Dentária , Traumatismos Dentários , Brasil , Pré-Escolar , Estudos Transversais , Humanos , Saúde Bucal , Prevalência , Qualidade de Vida , Inquéritos e QuestionáriosRESUMO
INTRODUCTION: Investigating preschool children's social behaviors and the association with oral health variables helps to understand child development. Besides that, different perceptions need to be explored regarding the impact of oral problems on the social behavior between the child's self-report and parent's/caregiver's proxy report. OBJECTIVE: To determine which socioeconomic and oral factors are associated with difficulty sleeping and playing and the avoidance of smiling in preschoolers. METHODS: A cross-sectional study was conducted with a representative random sample of 769 pairs of parents/caregivers and 5-y-old preschoolers. The preschoolers answered a questionnaire on difficulty sleeping, difficulty playing, and the avoidance of smiling for reasons related to oral problems. The parents/caregivers answered a questionnaire addressing socioeconomic characteristics as well as the use of dental services. Two calibrated dentists examined the children for the determination of dental caries, traumatic dental injury (TDI), malocclusion, and bruxism. Descriptive and Poisson regression analysis for complex samples with robust variance was used to test the associations (α = 5%). RESULTS: The variables associated with difficulty sleeping were low household income (confidence interval [CI]: 1.40-3.01), number of untreated dental caries (CI, 1.02-1.04), dental pain (CI, 1.76-3.59), TDI (CI, 1.08-2.11), and anterior open bite (CI, 1.11-2.20). Difficulty playing also was associated with the low household income (CI, 1.34-3.15), number of untreated dental caries (CI, 1.01-1.04), dental pain (CI,1.42-3.61), and TDI (CI, 1.13-2.33). The number of untreated dental caries (CI, 1.02-1.05), dental pain (CI, 1.03-2.88), anterior open bite (CI, 1.30-3.26), and not using dental services (CI, 1.13-2.73) were determinant factors for the avoidance of smiling. CONCLUSION: Socioeconomic, symptomatic, and/or oral esthetic problems exerted an impact on the social behavior of the preschoolers analyzed, such as playing, sleeping, and smiling. KNOWLEDGE TRANSFER STATEMENT: The results of the present study may help parents and clinicians to understand better the association of oral problems with the social behavior of preschool children. Moreover, this study shows the importance of listening to children in clinical decisions. These results also can help in the elaboration of oral health policies.
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Cárie Dentária , Traumatismos Dentários , Pré-Escolar , Estudos Transversais , Cárie Dentária/epidemiologia , Humanos , Qualidade de Vida , Autoimagem , Comportamento SocialRESUMO
Organ damage predicts mortality, increased accrual of detriment, and poor quality of life in systemic lupus erythematosus patients. The objective of this study is to determine the damage-free survival and its predictive factors in a population of Colombian subjects. The method used in this study is the retrospective follow-up of a cohort; damage was measured with SLICC/ACR index. Predictors of impairment were assessed by logistic regression and survival analysis. One hundred sixty-one individuals were included; 28.9% suffered damage, primarily neuropsychiatric, renal, and vascular. Arterial hypertension, antiphospholipid antibodies, prednisone dose, and number of relapses were all predictors of detriment. Onset after age 50 and daily prednisone dose higher than 7.5 mg determined earlier occurrence of damage.
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Anticorpos Antifosfolipídeos/sangue , Hipertensão/fisiopatologia , Rim/fisiopatologia , Lúpus Eritematoso Sistêmico/imunologia , Adolescente , Adulto , Colômbia , Progressão da Doença , Feminino , Humanos , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Lúpus Eritematoso Sistêmico/fisiopatologia , Masculino , Pessoa de Meia-Idade , Recidiva , Estudos Retrospectivos , Índice de Gravidade de Doença , Adulto JovemRESUMO
AIM: To evaluate the prevalence of sleep bruxism and associated factors among children aged 3-12 years as reported by parents via a questionnaire. METHODS: A cross-sectional study was conducted with a sample of 148 parents/caregivers of children aged 3-12 years treated at paediatric dentistry clinics. Parents/caregivers answered a questionnaire in the waiting room. Information on the gender and age of the child, age of parent/caregiver, meaning of bruxism and child's sleep (type of sleep, if he/she slept alone, hours of sleep per night and if nocturnal bruxism could affect his/her health) were collected. Descriptive statistics were performed and Poisson regression with robust variance was employed (p < 0.05). RESULTS: The prevalence of sleep bruxism was 32.4%. Most parents (64.2%) did not know the meaning of bruxism. In the final Poisson regression model, child's gender (PR 1.32; 95% CI 1.06-1.66) and restless sleep (PR 1.39; 95% CI 1.12-1.72) were significantly associated with sleep bruxism. CONCLUSION: The prevalence of sleep bruxism was high and was associated with gender and having restless sleep. Most parents/guardians did not know the meaning of bruxism.
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Bruxismo do Sono/epidemiologia , Brasil/epidemiologia , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Masculino , Pais , Prevalência , Fatores Sexuais , Distúrbios do Início e da Manutenção do Sono/epidemiologia , Inquéritos e QuestionáriosRESUMO
O monitoramento das fases do sono do cavalo, através da observação postural, pode ser dividido em três fases: a primeira, o animal permanece em pé, com a cabeça baixa, orelhas relaxadas e um dos posteriores relaxado (tempo de ócio - TO) ; na segunda, transfere-se para decúbito esternal (DE) e na terceira, relaxa todo o corpo, indo para decúbito lateral (DL). Observou-se três animais durante 72 horas, para monitorar as fases posturais de descanso. Aproximadamente 80% do descanso ocorre à noite. A proporção TO x DE é uma característica individual. Todos apresentaram DL menor, não excedendo a 10% do período total de descanso, demonstrando que, mesmo esses animais estando em cocheiras, conservam seu instinto de presa.(AU)
Equine stages of sleep monitoring using postural observation can be divided into three phases: the first one remains standing, with the head lowered, the ears relaxed and one of the hind limbs relaxed (OT); second phase: sternal decubitus (DE) and third, lateral decubitus relaxing all body (DL). Three animals were observed for 72 hours to monitor postural rest phases. Approximately 80% of rest occurs at night. The ratio TO x DE is an individual characteristic. All of them presented lower DL, not exceeding 10% of the total rest period, demonstrating that even these animals are in stalls, they retain their prey instinct.(AU)
Assuntos
Animais , Cavalos/fisiologia , Fases do Sono/fisiologia , PosturaRESUMO
O monitoramento das fases do sono do cavalo, através da observação postural, pode ser dividido em três fases: a primeira, o animal permanece em pé, com a cabeça baixa, orelhas relaxadas e um dos posteriores relaxado (tempo de ócio - TO) ; na segunda, transfere-se para decúbito esternal (DE) e na terceira, relaxa todo o corpo, indo para decúbito lateral (DL). Observou-se três animais durante 72 horas, para monitorar as fases posturais de descanso. Aproximadamente 80% do descanso ocorre à noite. A proporção TO x DE é uma característica individual. Todos apresentaram DL menor, não excedendo a 10% do período total de descanso, demonstrando que, mesmo esses animais estando em cocheiras, conservam seu instinto de presa.
Equine stages of sleep monitoring using postural observation can be divided into three phases: the first one remains standing, with the head lowered, the ears relaxed and one of the hind limbs relaxed (OT); second phase: sternal decubitus (DE) and third, lateral decubitus relaxing all body (DL). Three animals were observed for 72 hours to monitor postural rest phases. Approximately 80% of rest occurs at night. The ratio TO x DE is an individual characteristic. All of them presented lower DL, not exceeding 10% of the total rest period, demonstrating that even these animals are in stalls, they retain their prey instinct.
Assuntos
Animais , Cavalos/fisiologia , Fases do Sono/fisiologia , PosturaRESUMO
Tissue-nonspecific alkaline phosphatase (TNAP) plays a crucial role during skeletal mineralization, and TNAP deficiency leads to the soft bone disease hypophosphatasia. TNAP is anchored to the external surface of the plasma membranes by means of a GPI (glycosylphosphatidylinositol) anchor. Membrane-anchored and solubilized TNAP displays different kinetic properties against physiological substrates, indicating that membrane anchoring influences the enzyme function. Here, we used Electron Spin Resonance (ESR) measurements along with spin labeled phospholipids to probe the possible dynamic changes prompted by the interaction of GPI-anchored TNAP with model membranes. The goal was to systematically analyze the ESR data in terms of line shape changes and of alterations in parameters such as rotational diffusion rates and order parameters obtained from non-linear least-squares simulations of the ESR spectra of probes incorporated into DPPC liposomes and proteoliposomes. Overall, the presence of TNAP increased the dynamics and decreased the ordering in the three distinct regions probed by the spin labeled lipids DOPTC (headgroup), and 5- and 16-PCSL (acyl chains). The largest change was observed for 16-PCSL, thus suggesting that GPI-anchored TNAP can give rise to long reaching modifications that could influence membrane processes halfway through the bilayer.
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1,2-Dipalmitoilfosfatidilcolina/metabolismo , Fosfatase Alcalina/metabolismo , Lipossomos/metabolismo , Animais , Células CHO , Cricetulus , Espectroscopia de Ressonância de Spin Eletrônica , Humanos , Marcadores de SpinRESUMO
The aim of this study was to evaluate the impact of oral conditions on functional limitations among preschoolers. A preschool-based, cross-sectional study was carried out with 843 preschoolers in Campina Grande, Brazil. Parents/caregivers answered a questionnaire addressing socio-demographic characteristics and perceptions regarding the general/oral health of their children as well as the Brazilian version of the Early Childhood Oral Health Impact Scale. The nonparametric Kruskal-Wallis test followed by Mann-Whitney test (α = 5%) was used to compare mean children's quality-of-life scores for each independent variable. Poisson regression analysis was used to test associations between the independent and dependent variables (difficulties eating, drinking and speaking) (α = 5%). The multivariate regression model involved a hierarchical approach with four levels (distal to proximal determinants): (i) socio-demographic aspects; (ii) health perceptions; (iii) oral conditions; and (iv) pain conditions. The prevalence of negative impact on function was 24.7% for eating/drinking and 8.0% for speaking. Significant associations were found between toothache and negative impact on eating/drinking (PR = 5.38; 95%CI: 3.20-9.02) as well as between high severity dental caries and negative impact on speaking (PR = 14.91; 95%CI: 1.98-112.32). Dental caries, traumatic dental injury and malocclusion were not significantly associated with a negative impact on eating or drinking. However, toothache was an indicator of negative impact on eating/drinking and dental caries severity was an indicator of negative impact on speaking.
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Cárie Dentária/epidemiologia , Ingestão de Alimentos , Fala , Odontalgia/epidemiologia , Brasil/epidemiologia , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Masculino , Qualidade de Vida , Análise de Regressão , Fatores Socioeconômicos , Inquéritos e QuestionáriosRESUMO
Bovine herpesvirus 5 (BoHV-5) is an α-herpesvirus that causes neurological disease in young cattle and is also occasionally involved in reproductive disorders. Although there have been many studies of the apoptotic pathways induced by viruses belonging to the family Herpesviridae, there is little information about the intrinsic programmed cell death pathway in host-BoHV-5 interactions. We found that BoHV-5 is able to replicate in both mesenchymal and epithelial cell lines, provoking cytopathology that is characterized by cellular swelling and cell fusion. Viral antigens were detected in infected cells by immunofluorescence assay at 48 to 96 h post-infection (p.i.). At 48 to 72 h p.i., anti-apoptotic BCL-2 antigens were found at higher levels than Bax antigens; the latter is considered a pro-apoptotic protein. Infected cells had increased BCL-2 phenotype cells from 48 to 96 h p.i., based on flow cytometric analysis. At 48 to 96 h p.i., Bax mRNA was not expressed in any of the infected cell monolayers. In contrast, BCL-2 mRNA was found at high levels at all p.i. in both types of cells. BoHV-5 replication apparently modulates BCL-2 expression and gene transcription, enhancing production of virus progeny.
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Doenças dos Bovinos/virologia , Infecções por Herpesviridae/veterinária , Infecções por Herpesviridae/virologia , Herpesvirus Bovino 5/isolamento & purificação , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteína X Associada a bcl-2/genética , Animais , Apoptose , Bovinos/genética , Linhagem Celular , Sobrevivência Celular , Células Epiteliais/virologia , Regulação da Expressão Gênica , Herpesvirus Bovino 5/fisiologia , Células-Tronco Mesenquimais/metabolismo , Células-Tronco Mesenquimais/virologia , Mitocôndrias/genética , Mitocôndrias/metabolismo , Fenótipo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Replicação ViralRESUMO
AIM: To assess the prevalence of traumatic dental injury (TDI), as well as associated factors, behaviour of affected schoolchildren and normative treatment needs. METHODS: The present cross-sectional study involved 590 children aged 7-14 years at state schools in Campina Grande, Brazil. The O'Brien classification [1994] was used for the diagnosis of TDI and the body mass index (BMI) was used as an indicator of overweight/obesity. Clinical tests were carried out by two duly calibrated examiners (intra-observer and inter-observer agreement: 0.87 and 0.90, respectively). The Chi-square test was used (5% level of significance) to determine whether TDI was associated with age, gender, ethnicity, overweight/obesity, lip seal and overjet. Backward stepwise multivariate regression analysis was performed. Normative treatment needs were determined based on the criteria of the International Association of Dental Traumatology (IADT). When the absence of treatment was detected, each child/adolescent was asked about the reason for non-treatment. RESULTS: The prevalence of TDI was 12.7%. The most common type of trauma was enamel fracture (67.0%), followed by enamel-dentine fracture (25.3%). TDI was 4.9-fold greater (95% CI: 1.6-14.4) among children aged 13 and 14 years, 1.9- fold greater (95% CI: 1.1-3.2) among males and 2.6-fold greater (95% CI: 1.2-5.4) among those with inadequate lip seal. The majority of schoolchildren did not undergo treatment (82.6%) due to a belief that it was unnecessary (53.2%). The normative clinical evaluation revealed that adhesive restoration was the most common form of treatment (84.0%). CONCLUSION: The prevalence of TDI was low. Age, gender and inadequate lip seal were associated with dental trauma. A significant number of schoolchildren did not receive treatment for dental trauma.
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Traumatismos Dentários/epidemiologia , Adolescente , Fatores Etários , Índice de Massa Corporal , Brasil/epidemiologia , Criança , Comportamento Infantil , Estudos Transversais , Esmalte Dentário/lesões , Restauração Dentária Permanente/estatística & dados numéricos , Dentina/lesões , Etnicidade/estatística & dados numéricos , Feminino , Humanos , Lábio/patologia , Masculino , Avaliação das Necessidades/estatística & dados numéricos , Obesidade/epidemiologia , Sobremordida/epidemiologia , Sobrepeso/epidemiologia , Prevalência , Fatores Sexuais , Fraturas dos Dentes/epidemiologiaRESUMO
AIMS: Assessment of biological control of Cercospora sojina, causal agent of frogeye leaf spot (FLS) of soya bean, using three indigenous bacterial strains, BNM297 (Pseudomonas fluorescens), BNM340 and BNM122 (Bacillus amyloliquefaciens). METHODS AND RESULTS: From cultures of each bacterial strain, cell suspensions and cell-free supernatants were obtained and assayed to determine their antifungal activity against C. sojina. Both mycelial growth and spore germination in vitro were more strongly inhibited by bacterial cell suspensions than by cell-free supernatants. The Bacillus strains BNM122 and BNM340 inhibited the fungal growth to a similar degree (I ≈ 52-53%), while cells from P. fluorescens BNM297 caused a lesser reduction (I ≈ 32-34%) in the fungus colony diameter. The foliar application of the two Bacillus strains on soya bean seedlings, under greenhouse conditions, significantly reduced the disease severity with respect to control soya bean seedlings and those sprayed with BNM297. This last bacterial strain was not effective in controlling FLS in vivo. CONCLUSIONS: Our data demonstrate that the application of antagonistic bacteria may be a promising and environmentally friendly alternative to control the FLS of soya bean. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first report of biological control of C. sojina by using native Bacillus strains.
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Ascomicetos/efeitos dos fármacos , Bacillus , Glycine max , Doenças das Plantas/microbiologia , Pseudomonas fluorescens , Folhas de Planta/microbiologiaRESUMO
BACKGROUND: Popliteal arterial injuries carry a high risk of amputation. The currently available literature from both civilian and military experiences is characterized by a wide variation of recommendations for surgical management. We questioned how these recommendations have been applied in our practice. Therefore, we aimed to identify predictors of amputation after popliteal arterial injury. METHODS: We conducted an observational study of 175 patients with popliteal arterial injuries who underwent surgical treatment from 1992 to 2006 at a level I trauma center in Cali, Colombia. Information on demographic characteristics, clinical information, and surgical management was collected from clinical records. The outcome measure was amputation within 30 days following the first surgical intervention. RESULTS: The amputation rate was 17.1%. A multivariable logistic regression model indicates that blunt mechanism (odds ratio [OR] 4.79, 95% confidence interval [CI] 1.49-15.42), signs of ischemia (OR 5.29, 95% CI 1.48-18.91), ligation of the popliteal vein of the compromised limb during surgical exploration (OR 3.83, 95% CI 1.20-12.18), and the development of arterial thrombosis (OR 56.51, 95% CI 12.36-258) were found to be independent predictors of amputation. Fractures, popliteal venous injuries, prolonged time between injury and surgery, fasciotomies, and graft arterial repair were not statistically significant predictors of amputation. CONCLUSIONS: Emphasis on the early assessment and prompt identification of signs of ischemia after popliteal arterial injury continue to be the most important factor for reducing the risk of amputation, especially in blunt trauma. Vascular trauma teams must emphasize the need for the specialized management of popliteal veins. Clinical research is needed in order to identify means of decreasing arterial thrombosis after popliteal repair.
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The purpose of this study was to isolate and select indigenous soil Pseudomonas and Bacillus bacteria capable of developing multiple mechanisms of action related to the biocontrol of phytopathogenic fungi affecting soybean crops. The screening procedure consisted of antagonism tests against a panel of phytopathogenic fungi, taxonomic identification, detection by PCR of several genes related to antifungal activity, in vitro detection of the antifungal products, and root colonization assays. Two isolates, identified and designated as Pseudomonas fluorescens BNM296 and Bacillus amyloliquefaciens BNM340, were selected for further studies. These isolates protected plants against the damping-off caused by Pythium ultimum and were able to increase the seedling emergence rate after inoculation of soybean seeds with each bacterium. Also, the shoot nitrogen content was higher in plants when seeds were inoculated with BNM296. The polyphasic approach of this work allowed us to select two indigenous bacterial strains that promoted the early development of soybean plants.
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Porcine S100A12 is a member of the S100 proteins, family of small acidic calcium-binding proteins characterized by the presence of two EF-hand motifs. These proteins are involved in many cellular events such as the regulation of protein phosphorylation, enzymatic activity, protein-protein interaction, Ca2+ homeostasis, inflammatory processes and intermediate filament polymerization. In addition, members of this family bind Zn2+ or Ca2+ with cooperative effect on binding. In this study, the gene sequence encoding porcine S100A12 was obtained by the synthetic gene approach using E. coli codon bias. Additionally, we report a thermodynamic study of the recombinant S100A12 using circular dichroism, fluorescence and isothermal titration calorimetry. The results of urea and temperature induced unfolding and refolding processes indicated a reversible two-state process. Also, the ANS fluorescence studies showed that in presence of divalent ions the protein exposes hydrophobic sites which could facilitate the interaction with other proteins and trigger the physiological responses.
Assuntos
Dobramento de Proteína , Proteínas S100/química , Proteínas S100/metabolismo , Suínos/metabolismo , Animais , Cálcio/química , Cálcio/metabolismo , Calorimetria , Dicroísmo Circular , Expressão Gênica , Concentração de Íons de Hidrogênio , Ligação Proteica , Desnaturação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/classificação , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas S100/classificação , Proteínas S100/isolamento & purificação , Temperatura , Termodinâmica , Zinco/química , Zinco/metabolismoRESUMO
This article correlates colonization with parameters, such as chemotaxis, biofilm formation, and bacterial growth, that are believed to be connected. We show here, by using two varieties of soybean plants that seeds axenically produced exudates, induced a chemotactic response in Bacillus amyloliquefaciens, whereas root exudates did not, even when the exudates, also collected under axenic conditions, were concentrated up to 200-fold. Root exudates did not support bacterial cell division, whereas seed exudates contain compounds that support active cell division and high cell biomass at stationary phase. Seed exudates of the two soybean varieties also induced biofilm formation. B. amyloliquefaciens colonized both seeds and roots, and plant variety significantly affected bacterial root colonization, whereas it did not affect seed colonization. Colonization of roots in B. amyloliquefaciens occurred despite the lack of chemotaxis and growth stimulation by root exudates. The data presented in this article suggest that soybean seed colonization, but not root colonization, by B. amyloliquefaciens is influenced by chemotaxis, growth, and biofilm formation and that this may be caused by qualitative changes of the composition of root exudates.
Assuntos
Bacillus/fisiologia , Biofilmes/crescimento & desenvolvimento , Quimiotaxia , Glycine max/microbiologia , Raízes de Plantas/microbiologia , Sementes/microbiologia , Bacillus/efeitos dos fármacos , Bacillus/crescimento & desenvolvimento , Bacillus/isolamento & purificação , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Exsudatos de Plantas/química , Exsudatos de Plantas/farmacologia , Exsudatos de Plantas/fisiologia , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Sementes/química , Sementes/metabolismo , Microbiologia do Solo , Glycine max/química , Glycine max/metabolismoRESUMO
Photosynthetic bradyrhizobia are nitrogen-fixing symbionts colonizing the stem and roots of some leguminous plants like Aeschynomene. The effect of oxygen and light on the formation of the photosynthetic apparatus of Bradyrhizobium sp. C7T1 strain is described here. Oxygen is required for growth, but at high concentration inhibits the synthesis of bacteriochlorophyll (BChl) and of the photosynthetic apparatus. However, we show that in vitro, aerobic photosynthetic electron transport occurred leading to ADP photophosphorylation. The expression of the photosynthetic apparatus was regulated by oxygen in a manner which did not agree with earlier results in other photosynthetic bradyrhizobia since BChl accumulation was the highest under microaerobic conditions. This strain produces photosynthetic pigments when grown under cyclic illumination or darkness. However, under continuous white light illumination, a Northern blot analysis of the puf operon showed that, the expression of the photosynthetic genes of the antenna was considerable. Under latter conditions BChl accumulation in the cells was dependent on the oxygen concentration. It was not detectable at high oxygen tensions but became accumulated under low oxygen (microaerobiosis). It is known that in photosynthetic bradyrhizobia bacteriophytochrome photoreceptor (BphP) partially controls the synthesis of the photosystem in response to light. In C7T1 strain far-red light illumination did not stimulate the synthesis of the photosynthetic apparatus suggesting the presence of a non-functional BphP-mediated light regulatory mechanism.
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Bradyrhizobium/metabolismo , Luz , Óperon , Oxigênio , Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo , Trifosfato de Adenosina/biossíntese , Bradyrhizobium/genética , Regulação Bacteriana da Expressão GênicaRESUMO
AIMS: A bacterial strain producing antifungal compounds active against the plant pathogenic fungi Fusarium, Rhizoctonia and Sclerotinia has been characterized and shown to control Rhizoctonia root rot of soya bean. METHODS AND RESULTS: The metabolites excreted by Bacillus BNM 122 remained active after autoclaving, were resistant over a wide pH range and to hydrolytic enzymes. By (1)H-NMR and thin-layer chromatography analyses surfactin and iturin-like compounds were partially identified. Moreover, soya bean seeds bacterization with BNM 122 in a compost-based formulation was as effective controlling Rhizoctonia solani as pentachloronitrobenzene. According to its 16S rDNA sequence BNM 122 was closely related to Bacillus amyloliquefaciens and Bacillus subtilis. PCR analysis of the 16S-23S rRNA intergenic spacer region and repetitive sequence-based PCR (rep-PCR) genomic fingerprinting revealed a close genetic relationship to B. amyloliquefaciens. However, by physiological characterization using API tests, this strain resembled more B. subtilis. CONCLUSIONS: This is the first report describing the co-production of surfactin and iturin-like compounds by a putative strain of B. amyloliquefaciens. The synergistic effect of both lipopetides is a remarkable trait for a candidate biocontrol agent. SIGNIFICANCE AND IMPACT OF THE STUDY: This kind of research has relevance in order to minimize the use of synthetic fungicides and surfactants, contributing to the preservation of the environment.
Assuntos
Bacillus/genética , Inibidores Enzimáticos/metabolismo , Fungicidas Industriais/metabolismo , Peptídeos Cíclicos/metabolismo , Ascomicetos/metabolismo , Bacillus/metabolismo , Sequência de Bases/genética , Cromatografia em Camada Fina/métodos , DNA Bacteriano/genética , DNA Ribossômico/genética , Fusarium/metabolismo , Germinação/fisiologia , Lipopeptídeos , Espectroscopia de Ressonância Magnética/métodos , Dados de Sequência Molecular , Controle Biológico de Vetores/métodos , Rhizoctonia/metabolismo , Sementes/microbiologia , Glycine max/microbiologia , Esporos Fúngicos/metabolismoRESUMO
Cells of Rhv. sulfidophilum were grown under different conditions in the presence of 32P-phosphate and the corresponding H and L membrane fractions obtained and fractionated by SDS-PAGE. Both membranes showed almost identical polypeptide composition. The bacteriochlorophyll (Bchl) specific content in H was always lower that in L. As described before, oxygen did not regulate gene expression. Under high light, an almost two- to threefold decrease of the cellular specific Bchl content was observed. Pulse and chase experiments showed that transitions from aerobiosis to light-anaerobiosis did not quantitatively affect the Bchl content of the membranes, although a turnover of the 32P-phosphate and 35S-methionine was observed. LHI beta was the only polypeptidic subunit of the Bchl-binding polypeptides that was phosphorylated in vivo, and phosphotyrosine was the only phosphorylated amino acid detectable. The phosphorylated LHI beta was determined to be insoluble in the organic solvent mixture of (vol/vol) 1:1 chloroform-methanol containing ammonium acetate (0.1 m final concentration). Treatment with a chaotropic agent such as Na2CO3 solubilized the phosphorylated LHI beta, indicating that part of this posttranslationally modified polypeptide was not inserted in a transmembrane position. These results were used to speculate about the regulatory properties of this posttranslational modification of LHI beta on membrane differentiation.
Assuntos
Alphaproteobacteria/metabolismo , Proteínas de Bactérias , Membrana Celular/metabolismo , Complexos de Proteínas Captadores de Luz , Complexo de Proteínas do Centro de Reação Fotossintética/metabolismo , Alphaproteobacteria/crescimento & desenvolvimento , Bacterioclorofilas/metabolismo , Carbonatos/farmacologia , Eletroforese em Gel de Poliacrilamida , Regulação Bacteriana da Expressão Gênica , Luz , Fosforilação , Fotossíntese/fisiologia , Complexo de Proteínas do Centro de Reação Fotossintética/isolamento & purificaçãoRESUMO
We show in this paper that a complex constituted by phospholipids and LHI and LHII alpha polypeptides was inserted in a heavy membrane fraction in a nonextractable form, indicating a transmembrane localization. The best accepting membranes originated from aerobically grown cells. Addition of ATP during the insertion inhibited this reaction 25 to 30% in heavy membranes isolated from aerobically grown cells (HMaer) and a higher inhibition (60 to 65%) was detected when using heavy membranes isolated from photosynthetically grown cells (HMpho). Purification by gel filtration of a crude Na2CO3 extract yielded three phosphate-labeled fractions. Two of them contained protein and phospholipids in a stable association. However, only fractions containing phosphatidylethanolamine were shown to be reconstituted. The third radioactive fraction contained labeled ATP and protein, but no phospholipids and could not be reassociated to the heavy membranes of any origin. A model for the insertion of the LH polypeptides is presented in which the recently synthesized polypeptides are phosphorylated and become associated to anionic phospholipids. The interaction of this complex to the membrane spontaneously leads to stable insertion.