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A new type of large area sensor for infrared imaging bolometers has been developed. It replaces the thin and fragile free-standing metal foils, which typically have been used, with a multi-layer coated sapphire (or diamond) substrate. Sapphire is transparent to mid-infrared wavelengths, is robust against transients, and can be thick enough to even be the vacuum window. The primary radiation absorber is still a thin deposited metal layer, but now it is partially insulated from the supporting sapphire substrate by a black (carbon-based) layer, which also acts as a blackbody remitter. Test results indicate 6× more noise equivalent power density (estimated NEPD = 23 W/m2 at 5 ms camera exposure time, foil temperature decay time 60 ms) for a 2 µm gold-coated sapphire disk compared to estimated NEP = 4 W/m2 at 1.8 ms exposure time, with foil decay time 420 ms, for a nominal 2.5 µm thick platinum-free-standing foil.
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Hyperoxaluria is a pathological condition which affects long-term health of kidneys. The present study evaluates the impact of the combination of Lactobacillus amylovorus SGL 14 and the plant extract Phyllantus niruri (namely Phyllantin 14™) on dietary hyperoxaluria. Safety and efficacy of Phyllantin 14 have been evaluated in vivo. Mice C57BL6 fed a high-oxalate diet were compared to mice fed the same diet administered with Phyllantin 14 by gavage for 6 weeks. Control mice were fed a standard diet without oxalate. No adverse effects were associated to Phyllantin 14 supplementation, supporting its safety. Mice fed a high-oxalate diet developed significant hyperoxaluria and those administered with Phyllantin 14 showed a reduced level of urinary oxalate and a lower oxalate-to-creatinine ratio. Soluble and insoluble caecal oxalate were significantly lower in treated group, a finding in agreement with the colonisation study, i.e. mice were colonised with SGL 14 after 3 weeks. Microbiota analysis demonstrated that both oxalate diet and Phyllantin 14 can differently modulate the microbiota. In conclusion, our findings suggest that Phyllantin 14 supplementation represents a potential supportive approach for reducing urinary oxalate and/or for enhancing the efficacy of existing treatments.
Assuntos
Dieta , Hiperoxalúria/terapia , Lactobacillus acidophilus , Oxalatos/administração & dosagem , Phyllanthus , Extratos Vegetais/uso terapêutico , Animais , Aderência Bacteriana , Ceco/química , Modelos Animais de Doenças , Fezes/química , Microbioma Gastrointestinal , Células HT29 , Humanos , Hiperoxalúria/tratamento farmacológico , Hiperoxalúria/patologia , Rim/patologia , Lactobacillus acidophilus/crescimento & desenvolvimento , Lactobacillus acidophilus/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oxalatos/análise , Oxalatos/urina , Fitoterapia , ProbióticosRESUMO
Rare truncating BRCA2 K3326X (rs11571833) and pathogenic CHEK2 I157T (rs17879961) variants have previously been implicated in familial pancreatic ductal adenocarcinoma (PDAC), but not in sporadic cases. The effect of both mutations in important DNA repair genes on sporadic PDAC risk may shed light on the genetic architecture of this disease. Both mutations were genotyped in germline DNA from 2,935 sporadic PDAC cases and 5,626 control subjects within the PANcreatic Disease ReseArch (PANDoRA) consortium. Risk estimates were evaluated using multivariate unconditional logistic regression with adjustment for possible confounders such as sex, age and country of origin. Statistical analyses were two-sided with p values <0.05 considered significant. K3326X and I157T were associated with increased risk of developing sporadic PDAC (odds ratio (ORdom ) = 1.78, 95% confidence interval (CI) = 1.26-2.52, p = 1.19 × 10-3 and ORdom = 1.74, 95% CI = 1.15-2.63, p = 8.57 × 10-3 , respectively). Neither mutation was significantly associated with risk of developing early-onset PDAC. This retrospective study demonstrates novel risk estimates of K3326X and I157T in sporadic PDAC which suggest that upon validation and in combination with other established genetic and non-genetic risk factors, these mutations may be used to improve pancreatic cancer risk assessment in European populations. Identification of carriers of these risk alleles as high-risk groups may also facilitate screening or prevention strategies for such individuals, regardless of family history.
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Proteína BRCA2/genética , Carcinoma Ductal Pancreático/genética , Quinase do Ponto de Checagem 2/genética , Genes BRCA2 , Neoplasias Pancreáticas/genética , Idoso , Estudos de Casos e Controles , Feminino , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo ÚnicoRESUMO
AIMS: The aim of this study was to investigate the antimicrobial potential of proteins secreted by a new strain of Lactobacillus salivarius. METHODS AND RESULTS: The secretome of L. salivarius SGL 03 strain was analysed by gel-assisted fractionation and MS/MS to identify low-molecular-mass proteins. This strategy allowed us to identify 10 secreted proteins. Then, a combination of heterologous expression and agar well diffusion was used to characterize them as to their antimicrobial activity, mechanisms of action and stability. Our findings indicate that L27 and L30 proteins of the 50S ribosomal subunit have antimicrobial activity against Streptococcus pyogenes, Streptococcus uberis and Enterococcus faecium. In addition, both proteins are bactericidal against S. pyogenes and maintain their antimicrobial activity after different protease treatments, at acidic pH, after heat treatment, and if stored in a refrigerated ambient at least at 4°C. CONCLUSIONS: The overall results demonstrated that the L27 and L30 ribosomal proteins are of interest as new antimicrobial molecules to prevent the growth of S. pyogenes, S. uberis and E. faecium. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results provide the first insight into the extra-ribosomal activity of L27 and L30 secreted proteins of L. salivarius. This study demonstrated the capacity of L. salivarius SGL 03 to produce antimicrobial molecules and suggested this strain as a promising probiotic candidate.
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Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Ligilactobacillus salivarius/metabolismo , Proteínas Ribossômicas/isolamento & purificação , Proteínas Ribossômicas/farmacologia , Antibacterianos/química , Enterococcus faecium/efeitos dos fármacos , Humanos , Ligilactobacillus salivarius/química , Ligilactobacillus salivarius/classificação , Proteínas Ribossômicas/química , Streptococcus/efeitos dos fármacos , Espectrometria de Massas em TandemRESUMO
Age estimation from teeth by radiological analysis, in both children and adolescents, has wide applications in several scientific and forensic fields. In 2006, Cameriere et al. proposed a regression method to estimate chronological age in children, according to measurements of open apices of permanent teeth. Although several regression models are used to analyze the relationship between age and dental development, one serious limitation is the unavoidable bias in age estimation when regression models are used. The aim of this paper is to develop a full Bayesian calibration method for age estimation in children according to the sum of open apices, S, of the seven left permanent mandibular teeth. This cross-sectional study included 2630 orthopantomographs (OPGs) from healthy living Italian subjects, aged between 4 and 17 years and with no obvious developmental abnormalities. All radiographs were in digital format and were processed by the ImageJ computer-aided drawing program. The distance between the inner side of the open apex was measured for each tooth. Dental maturity was then evaluated according to the sum of normalized open apices (S). Intra- and inter-observer agreement was satisfactory, according to an intra-class correlation coefficient of S on 50 randomly selected OPGs. Mean absolute errors were 0.72 years (standard deviation 0.60) and 0.73 years (standard deviation 0.61) in boys and girls, respectively. The mean interquartile range (MIQR) of the calibrating distribution was 1.37 years (standard deviation 0.46) and 1.51 years (standard deviation 0.52) in boys and girls, respectively. Estimate bias was ßERR=-0.005 and 0.003 for boys and girls, corresponding to a bias of a few days for all individuals in the sample. Neither of the ßERR values was significantly different from 0 (p>0.682). In conclusion, the Bayesian calibration method overcomes problems of bias in age estimation when regression models are used, and appears to be suitable for assessing both age and age distribution in children according to tooth maturity.
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Determinação da Idade pelos Dentes/métodos , Modelos Estatísticos , Ápice Dentário/diagnóstico por imagem , Ápice Dentário/crescimento & desenvolvimento , Adolescente , Teorema de Bayes , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Radiografia PanorâmicaRESUMO
An open problem in applied mathematics is to predict interesting molecules that are realistic targets for chemical synthesis. In this paper, we use a spin Hamiltonian-type model to predict molecular magnets (MMs) with magnetic moments that are intrinsically robust under random shape deformations to the molecule. Using the concept of convergence in probability, we show that for MMs in which all spin centres lie in-plane and all spin centre interactions are ferromagnetic, the total spin of the molecule is a 'weak topological invariant' when the number of spin centres is sufficiently large. By weak topological invariant, we mean that the total spin of the molecule depends only upon the arrangement of spin centres in the molecule, and is unlikely to change under shape deformations to the molecule. Our calculations show that only between 20 and 50 spin centres are necessary for the total spin of these MMs to be a weak topological invariant. The robustness effect is particularly enhanced for two-dimensional ferromagnetic MMs that possess a small number of spin rings in the structure.
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AIMS: To investigate the effect of support and growth medium (GM) on Pleurotus ostreatus biofilm production, specific metabolic activity (SMA) and ultrastructure. METHODS AND RESULTS: Biofilms were developed on membranes covering a broad range of surface properties and, due to the applicative implications of mixed biofilms, on standard bacterial GM in stationary and shaken culture. Hydrophilic (glass fibre, Duran glass and hydroxyapatite) and mild hydrophobic (polyurethane, stainless steel, polycarbonate, nylon) supports were more adequate for biofilm attachment than the hydrophobic Teflon. Among the GM, sucrose-asparagine (SA) was more conducive to biofilm production than Luria-Bertani and M9. GM was more influential than support type on biofilm ultrastructure, and a high compactness was evident in biofilms developed on SA. Biofilms on Duran glass were more efficient than planktonic cultures in olive-mill wastewater treatment. CONCLUSIONS: The main effects of support and GM variables and their binary interactions on both biofilm production and SMA were all highly significant (P < 0·001): thus, the magnitude of the effect of each variable strongly depended on the level of the other one. SIGNIFICANCE AND IMPACT OF THE STUDY: There is a lack of basic information regarding physiology and ultrastructure of P. ostreatus biofilms. To our knowledge, this is the first attempt to fill this gap, thus representing a basis for future studies.
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Biofilmes/crescimento & desenvolvimento , Pleurotus/fisiologia , Meios de Cultura , Vidro , Interações Hidrofóbicas e Hidrofílicas , Plâncton , Pleurotus/metabolismo , Pleurotus/ultraestrutura , Aço Inoxidável , Propriedades de SuperfícieRESUMO
OBJECTIVES: The aim of this study is to examine if urban pollution can modify indices of genotoxic damage. METHODS: Research of articles inherent in the evaluation of these alterations. Differents categories of exposed workers are included in the study (cases, in number of 7287) and compaired with no exposed workers (controls, in number of 8054). To calculate the result of meta-analysis the Effect Size (ES) was used and the confidence interval was calculated. RESULTS: In this category we evaluated 54 studies and we observed significantly differences in the complex. CONCLUSIONS: Starting from the individual variables analysis investigated, between exposed and not exposed group, we underline the utility to deepen the studies concerning of these parameters, to appreciate their benefits and to safeguard health of exposed workers.
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Poluentes Atmosféricos/efeitos adversos , Dano ao DNA , Exposição Ocupacional/efeitos adversos , Saúde da População Urbana , HumanosRESUMO
INTRODUCTION: In the past the role of women was mainly that of wife and mother, over the centuries, this role has changed: women assert themselves in every social field and workplace. OBJECTIVES: Analyze the history of women's work, from prehistory to the present day highlighting the evolution of women's role over the centuries. Identify which may be the different occupational stressors, in particular the organizational and psycho-social ones, to which is submitted a working woman. MATERIALS AND METHODS: The authors have analyzed the most relevant data from literature, in particular on the issue of mental health. RESULTS: Provide the main forms of prevention that have to be implemented. DISCUSSION: The main challenge for women today, is to balance work outside the home and housework. This added to job stressors, may interfere with the psychological and physical wellbeing of the worker.
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Saúde Ocupacional , Saúde da Mulher , Feminino , HumanosRESUMO
Olive-mill wastewater (OMW) was investigated for its suitability to serve as a medium for lipase production by Candida cylindracea NRRL Y-17506. The OMW that best supported enzyme production was characterized by low COD and low total sugars content. In shake flask batch cultures, OMW supplementation with 2.4 g l(-1) NH(4)Cl and 3 g l(-1) olive oil led to an enzyme activity of about 10 U ml(-1). The addition of glucose or malt extract and supplements containing organic N (e.g., peptone, yeast extract) either depressed or did not affect the enzyme production. Further experiments were then performed in a 3-l stirred tank reactor to assess the impact of medium pH and stirring speed on the yeast enzyme activity. The lipase activity was low (1.8 U ml(-1)) when the pH was held constant at 6.5, significantly increased (18.7 U ml(-1)) with uncontrolled pH and was maximum (20.4 U ml(-1)) when the pH was let free to vary below 6.5. A stirring regime, that varied depending on the dissolved oxygen concentration in the medium, both prevented the occurrence of anoxic conditions during the exponential growth phase and enabled good lipase production (i.e., 21.6 U ml(-1)) and mean volumetric productivity (i.e., 123.5 Ul(-1)h(-1)).
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Reatores Biológicos , Candida/enzimologia , Candida/metabolismo , Microbiologia Industrial/métodos , Lipase/metabolismo , Biomassa , Biotecnologia/métodos , Meios de Cultura , Indústria Alimentícia , Glucose/química , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Resíduos Industriais , Azeite de Oliva , Oxigênio/metabolismo , Óleos de Plantas , Eliminação de Resíduos Líquidos , Gerenciamento de ResíduosRESUMO
AIMS: This study was undertaken to evaluate the oxalate-degrading activity in several Lactobacillus species widely used in probiotic dairy and pharmaceutical preparations. Functional characterization of oxalyl-CoA decarboxylase and formyl-CoA transferase in Lactobacillus acidophilus was performed in order to assess the possible contribution of Lactobacillus in regulating the intestinal oxalate homeostasis. METHODS AND RESULTS: In order to determine the oxalate-degrading ability in 60 Lactobacillus strains belonging to 12 species, a screening was carried out by using an enzymatic assay. A high variability in the oxalate-degrading capacity was found in the different species. Strains of Lact. acidophilus and Lactobacillus gasseri showed the highest oxalate-degrading activity. Oxalyl-CoA decarboxylase and formyl-CoA transferase genes from Lact. acidophilus LA14 were cloned and sequenced. The activity of the recombinant enzymes was assessed by capillary electrophoresis. CONCLUSIONS: Strains of Lactobacillus with a high oxalate-degrading activity were identified. The function and significance of Lact. acidophilus LA14 oxalyl-CoA decarboxylase and formyl-CoA transferase in oxalate catabolism were demonstrated. These results suggest the potential use of Lactobacillus strains for the degradation of oxalate in the human gut. SIGNIFICANCE AND IMPACT OF THE STUDY: Identification of probiotic strains with oxalate-degrading activity can offer the opportunity to provide this capacity to individuals suffering from an increased body burden of oxalate and oxalate-associated disorders.
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Microbiologia de Alimentos , Lactobacillus acidophilus/metabolismo , Oxalatos/metabolismo , Probióticos , Técnicas Bacteriológicas , Sequência de Bases , Carboxiliases/genética , Carboxiliases/metabolismo , Coenzima A-Transferases/genética , Coenzima A-Transferases/metabolismo , Eletroforese Capilar , Expressão Gênica , Genes Bacterianos , Lactobacillus acidophilus/genética , Dados de Sequência Molecular , Reação em Cadeia da Polimerase/métodos , Análise de Sequência de DNARESUMO
Nine fungal strains isolated from an aged and heavily contaminated soil were identified and screened to assess their degradative potential. Among them, Allescheriella sp. strain DABAC 1, Stachybotrys sp. strain DABAC 3, and Phlebia sp. strain DABAC 9 were selected for remediation trials on the basis of Poly R-478 decolorization associated with lignin-modifying enzyme (LME) production. These autochthonous fungi were tested for the abilities to grow under nonsterile conditions and to degrade various aromatic hydrocarbons in the same contaminated soil. After 30 days, fungal colonization was clearly visible and was confirmed by ergosterol determination. In spite of subalkaline pH conditions and the presence of heavy metals, the autochthonous fungi produced laccase and Mn and lignin peroxidases. No LME activities were detected in control microcosms. All of the isolates led to a marked removal of naphthalene, dichloroaniline isomers, o-hydroxybiphenyl, and 1,1'-binaphthalene. Stachybotrys sp. strain DABAC 3 was the most effective isolate due to its ability to partially deplete the predominant contaminants 9,10-anthracenedione and 7H-benz[DE]anthracen-7-one. A release of chloride ions was observed in soil treated with either Allescheriella sp. strain DABAC 1 or Stachybotrys sp. strain DABAC 3, suggesting the occurrence of oxidative dehalogenation. The autochthonous fungi led to a significant decrease in soil toxicity, as assessed by both the Lepidium sativum L. germination test and the Collembola mortality test.
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Fungos/metabolismo , Hidrocarbonetos Aromáticos/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Antraquinonas/metabolismo , Biodegradação Ambiental , DNA Fúngico/análise , DNA Espaçador Ribossômico/análise , DNA Espaçador Ribossômico/genética , Fungos/classificação , Fungos/crescimento & desenvolvimento , Fungos/isolamento & purificação , Lignina/metabolismo , Dados de Sequência Molecular , Filogenia , Polímeros/metabolismo , RNA Ribossômico/genética , Análise de Sequência de DNA , Stachybotrys/metabolismoRESUMO
AIMS: A molecular methodology based on PCR-associated automated ribotyping was developed to specifically detect the Lactobacillus strains of two probiotic products (an orally administered lyophilized preparation and vaginal tablets) in human faeces and vaginal swabs. METHODS AND RESULTS: The 16S-23S rDNA sequences and the ribotype profiles of the probiotic lactobacilli were characterized and new species-specific primer sets were designed. The identification of faecal and vaginal lactobacilli isolated from subjects administered with the probiotic products was performed by using PCR with species-specific primers followed by strain-specific automated ribotyping. CONCLUSIONS: The PCR-ribotyping identification allowed to study the colonization patterns of the probiotic lactobacilli in the human gut and vagina evidencing the strains with the best survival capability. SIGNIFICANCE AND IMPACT OF THE STUDY: The proposed molecular method represents a powerful tool of strain-specific identification, useful for differentiating exogenous from indigenous strains in any microbial ecosystem and for rationally choosing probiotic bacteria with the best chance of survival in the host.
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Intestinos/microbiologia , Lactobacillus/isolamento & purificação , Probióticos/análise , Vagina/microbiologia , Contagem de Colônia Microbiana , Processamento Eletrônico de Dados , Fezes/microbiologia , Feminino , Humanos , Lactobacillus/genética , Lactobacillus/metabolismo , Reação em Cadeia da Polimerase/métodos , Ribotipagem/métodosRESUMO
AIMS: Isolation and characterization of the glucose oxidase (GOX)-encoding gene from a Penicillium variabile strain (P16) having a high level of GOX activity and comparison of its expression with that of another strain of P. variabile (NRRL 1048) characterized by low GOX activity. METHODS AND RESULTS: The gene, isolated by PCR consisted of 1818 bp encoding 605 amino acid residues. Gene expression was analysed by Northern blotting and compared with that of P. variabile NRRL 1048. The higher GOX activity of strain P16 appeared likely because of de novo mRNA synthesis. Southern blotting analyses of the genomic DNA showed that the hybridization pattern of the two strains differed for the size of hybridizing fragment detected by the probe and slightly for their signal intensity. CONCLUSIONS: The GOX-encoding gene of P. variabile P16 was isolated and characterized to identify the molecular bases of its high level of expression and in view of improving enzyme production by developing a process based on heterologous expression. SIGNIFICANCE AND IMPACT OF THE STUDY: GOX-encoding genes can be subjected to high difference in their expression levels. The P16 strain of P. variable producing large amount of GOX as well as its encoding gene might be exploited for industrial applications.
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Glucose Oxidase/biossíntese , Glucose Oxidase/genética , Penicillium/enzimologia , Penicillium/genética , Sequência de Aminoácidos , Northern Blotting , Southern Blotting , Cromossomos Fúngicos/genética , Clonagem Molecular , DNA Fúngico/química , DNA Fúngico/isolamento & purificação , Expressão Gênica , Genes Fúngicos , Genoma Fúngico , Glucose Oxidase/metabolismo , Dados de Sequência Molecular , Polimorfismo Genético , RNA Mensageiro/análise , Alinhamento de Sequência , Análise de Sequência de DNA , Fatores de TempoRESUMO
Botryosphaeria rhodina produced beta-glucan when grown on undiluted olive-mill wastewaters (OMW). The production of exopolysaccharide increased with the COD up to 17.2 g l(-1) on the most loaded OMW (151 and 66 g l(-1) of COD and total sugar, respectively). The total phenol content of OMW was reduced from 8 to 4.1 g l(-1).
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Ascomicetos/crescimento & desenvolvimento , Ascomicetos/metabolismo , Reatores Biológicos/microbiologia , Técnicas de Cultura de Células/métodos , Glucanos/biossíntese , Olea/química , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos , Ascomicetos/classificação , Ascomicetos/citologia , Biodegradação Ambiental , Divisão Celular/fisiologia , Estudos de Viabilidade , Resíduos Industriais/prevenção & controle , Consumo de Oxigênio/fisiologia , Especificidade da EspécieRESUMO
AIMS: To purify and characterize the chitinolytic activity of Penicillium janthinellum P9 and to evaluate possible uses of the purified enzymes in the control of fungal growth and spore germination. METHODS AND RESULTS: The chitinolytic activity of P. janthinellum P9 was associated to two beta-N-acetyl-hexosaminidases (CHI1 and CHI2) that were purified by preparative isoelectric focusing and preparative electrophoresis and partially characterized. Treatment of test fungi with purified enzyme solutions caused reduced spore germination, reduction of hyphal length and mycelial damage. The combined action of the two enzymes and a systemic fungicide completely inactivated pests and food-spoiling moulds such as Fusarium solanii, P. canescens and Cladosporium cladosporioides. Treatment with the two enzymes increased germination of freeze-dried fungal spores. CONCLUSION: The chitinolytic activity of P. janthinellum P9 is associated with two extracellular beta-N-acetyl-hexosaminidases that can cause damage to the cell walls of other fungi. SIGNIFICANCE AND IMPACT OF THE STUDY: This appears to be the first report on the characterization of extracellular chitinolytic enzymes produced by a Penicillium strain. The results of this study might have some impact in the applied research field.
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Antifúngicos/isolamento & purificação , Antifúngicos/metabolismo , Quitina/metabolismo , Hexosaminidases/isolamento & purificação , Hexosaminidases/metabolismo , Penicillium/enzimologia , Antifúngicos/farmacologia , Eletroforese em Gel de Poliacrilamida , Microbiologia de Alimentos , Conservação de Alimentos , Liofilização , Hexosaminidases/farmacologia , Hifas/efeitos dos fármacos , Hifas/crescimento & desenvolvimento , Focalização Isoelétrica , Penicillium/metabolismo , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/fisiologia , Especificidade por SubstratoRESUMO
This paper reviews current knowledge of the production of organic acids by immobilized microorganisms with a simultaneous solubilization of rock phosphate in fermentation and soil conditions. The most widely applied methods are based on the passive immobilization in preformed porous carriers and entrapment of the microbial cells in natural gels. In general, immobilized systems show higher acid producing and rock phosphate solubilizing activity than freely suspended cells. The potential of gel-entrapped P-solubilizers and mycorrhizal fungi as microbial soil inoculants is also pointed out. Some advantages and constraints of using immobilized cells are discussed and a special emphasis on further research is given.
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Fosfatos/química , Fósforo/química , Raízes de Plantas/microbiologia , Microbiologia do Solo , Células Imobilizadas/fisiologia , Conservação dos Recursos Naturais , Fermentação , Fertilizantes , Compostos Orgânicos , SolubilidadeRESUMO
We have combined a confocal laser scanning head modified for TPE (two-photon excitation) microscopy with some spectroscopic modules to study single molecules and molecular aggregates. The behavior of the TPE microscope unit has been characterized by means of point spread function measurements and of the demonstration of its micropatterning abilities. One-photon and two-photon mode can be simply accomplished by switching from a mono-mode optical fiber (one-photon) coupled to conventional laser sources to an optical module that allows IR laser beam (two-photon/TPE) delivery to the confocal laser scanning head. We have then described the characterization of the two-photon microscope for spectroscopic applications: fluorescence correlation, lifetime and fluorescence polarization anisotropy measurements. We describe the measurement of the response of the two-photon microscope to the light polarization and discuss fluorescence polarization anisotropy measurements on Rhodamine 6G as a function of the viscosity and on a globular protein, the Beta-lactoglobulin B labeled with Alexa 532 at very high dilutions. The average rotational and translational diffusion coefficients measured with fluorescence polarization anisotropy and fluorescence correlation methods are in good agreement with the protein size, therefore validating the use of the microscope for two-photon spectroscopy on biomolecules.
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Microscopia Confocal , Microscopia de Fluorescência , Animais , Imageamento Tridimensional , Microscopia de Polarização , Modelos Teóricos , Fótons , Análise EspectralRESUMO
The production of itaconic acid from glucose-based media by Aspergillus terreus NRRL 1960 was found to be controlled by stirring rate and pH. When the phosphorous (P) level in the production medium was reduced to less than 10 mg l(-1), the fungal mycelium exhausted its primary growth and started to excrete itaconic acid, while it continued its secondary growth at the expense of ammoniacal nitrogen. The fermentation exhibited a mixed-growth-associated product formation kinetics, the non-growth associated production term (mI) being practically zero only when the pH was left free to change from 3.4 down to 1.85. On the contrary, when the pH was kept reducing up to a constant value by automatic addition of KOH 4 mol l(-1), the itaconate yield coefficient on the initial glucose supplied (Y(I/So)) and mI and were 0.53 g g(-1) and 0.028 h(-1) at pH 2.4 and 320 rev min(-1) and 0.5 g g(-1) and 0.036 h(-1) at pH 2.8 and 400 rev min(-1), respectively. Although the differences between mI and Y(I/So) were statistically insignificant at the 95% confidence level, the net difference in the corresponding yield coefficients for itaconic acid on mycelial biomass resulted in a maximum itaconate production rate of 0.41 g l(-1) h(-1) at pH 2.8 and 400 rev min(-1), thus showing that this operating condition is no doubt optimal for the process under study.