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1.
Int J Cancer ; 145(3): 686-693, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-30672594

RESUMO

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.


Assuntos
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 Único
2.
J Appl Microbiol ; 124(2): 398-407, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29159916

RESUMO

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.


Assuntos
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 Tandem
3.
Rev Sci Instrum ; 95(9)2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39225572

RESUMO

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.

4.
J Appl Microbiol ; 114(6): 1750-62, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23414514

RESUMO

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.


Assuntos
Biofilmes/crescimento & desenvolvimento , Pleurotus/fisiologia , Meios de Cultura , Vidro , Interações Hidrofóbicas e Hidrofílicas , Plâncton , Pleurotus/metabolismo , Pleurotus/ultraestrutura , Aço Inoxidável , Propriedades de Superfície
5.
G Ital Med Lav Ergon ; 34(3 Suppl): 740-3, 2012.
Artigo em Italiano | MEDLINE | ID: mdl-23405766

RESUMO

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.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Dano ao DNA , Exposição Ocupacional/efeitos adversos , Saúde da População Urbana , Humanos
6.
G Ital Med Lav Ergon ; 32(4): 458-60, 2010.
Artigo em Italiano | MEDLINE | ID: mdl-21086704

RESUMO

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.


Assuntos
Saúde Ocupacional , Saúde da Mulher , Feminino , Humanos
7.
Benef Microbes ; 11(6): 547-559, 2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33032472

RESUMO

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 , Probióticos
8.
Cancer Res ; 53(1): 19-26, 1993 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-8416745

RESUMO

2,2'-Bipyridyl-6-carbothioamide (BPYTA), a synthetic compound with antitumoral activity, is characterized by chelating properties because of the N*-N*-S* tridentate ligand system and is therefore comparable to alpha-(N)-heterocyclic carboxaldehyde thiosemicarbazones which are potent inhibitors of ribonucleotide reductase (RR). Electron paramagnetic resonance studies on the small subunit of mouse recombinant RR (R2) demonstrated that BPYTA can destroy the R2 tyrosyl radical only if Fe(II) is present (73% destruction at 50 microM, after 20 min of contact). The R2 inhibition was reversible and time dependent. Studies on tumoral lines confirmed that the main cell target of BPYTA is RR and demonstrated that the iron-complexed form compared to the nonchelated form has some difficulty in crossing the cell membrane. Spectrophotometric and electron paramagnetic resonance studies clearly indicated that BPYTA chelates iron only when this is reduced and that the BPYTA-Fe(II) complex is stable in the presence of oxygen. From reported results we conclude that BPYTA is a powerful RR inhibitor (R2 subunit) which has a different mechanism of action from that of Desferal. It has some properties in common with alpha-(N)-heterocyclic carboxaldehyde thiosemicarbazones, but they are not identical. It would be interesting to do further studies on the BPYTA mechanism of action and evaluate the in vivo antitumoral activity of the preformed complex.


Assuntos
2,2'-Dipiridil/análogos & derivados , Antineoplásicos/farmacologia , Compostos Ferrosos/farmacologia , Ribonucleotídeo Redutases/antagonistas & inibidores , 2,2'-Dipiridil/farmacologia , Animais , Divisão Celular/efeitos dos fármacos , Quelantes/farmacologia , Desferroxamina/farmacologia , Radicais Livres/metabolismo , Humanos , Ferro/farmacologia , Substâncias Macromoleculares , Camundongos , Tiossemicarbazonas/farmacologia , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/enzimologia
9.
Forensic Sci Int ; 258: 50-4, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26650061

RESUMO

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.


Assuntos
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 Panorâmica
10.
Thromb Haemost ; 64(2): 256-9, 1990 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-2270533

RESUMO

The pharmacokinetics and haemostatic effects of MF 701 dermatan sulfate (DS) administered by i.v. infusion were studied in 11 healthy volunteers. Each subject received 0.6 mg kg-1 h-1 MF 701 for 10 h. DS plasma concentrations were measured by a chromogenic assay based on the catalysis of thrombin inhibition by HCII. DS plasma levels followed a single compartment pharmacokinetic model, with a half-life of 1.28 +/- 0.46 h, a plasma clearance of 2.75 +/- 0.46 l/h and a volume of distribution of 4.92 +/- 1.36 1 (means +/- SD). Steady-state was reached 3 to 6 h after infusion started. The maximal DS plasma concentration was 16.4 +/- 5.7 micrograms/ml. Maximal APTT prolongation over pre-infusion values was 42 +/- 7%; TCT performed with bovine and human thrombin was prolonged by 16 +/- 7% and 83 +/- 35% respectively. No anti-IIa or anti-Xa activities were detected by chromogenic tests. The treatment was well tolerated. The pharmacokinetics of MF 701 infusion are consistent with those previously described after i.v. bolus administration. The infusion of MF 701 allows fast achievement and steady maintenance of elevated DS plasma concentrations.


Assuntos
Dermatan Sulfato/farmacocinética , Adolescente , Adulto , Compostos Cromogênicos , Dermatan Sulfato/administração & dosagem , Dermatan Sulfato/farmacologia , Feminino , Fibrinolíticos/administração & dosagem , Fibrinolíticos/farmacocinética , Fibrinolíticos/farmacologia , Hemostasia/efeitos dos fármacos , Humanos , Infusões Intravenosas , Masculino , Tempo de Tromboplastina Parcial , Tempo de Trombina
11.
Res Microbiol ; 149(4): 289-300, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9766230

RESUMO

The chitinolytic activity of Verticillium cfr. lecanii A3, a strain isolated from continental Antarctica, was compared to those of two selected strains of Trichoderma harzianum. After 72 h of incubation at 25 degrees C in media containing chitin as the sole carbon source, all strains showed the same enzyme activity (ca. 230 mU/ml); at 15 degrees C, the levels of enzyme activity of the three strains were similar to those obtained at 25 degrees C. At 5 degrees C, in contrast, the activity of V. lecanii was ca. 4 times higher than those of both strains of T. harzianum (203 and 57 mU/ml, respectively; incubation time 144 h). The chitinase of V. lecanii, purified by preparative isoelectric focusing and ion-exchange chromatography, was shown to be a glycoprotein with apparent molecular weight of 45 kDa and isoelectric point of 4.9. The enzyme was active over a broad range of temperatures (5-60 degrees C): at 5 degrees C, its relative activity was still 50% of that recorded at 40 degrees C (optimal temperature). V. lecanii and its purified chitinase showed clear inhibitory effects on the growth of some test moulds such as Mucor plumbeus, Cladosporium cladosporioides, Aspergillus versicolor and Penicillium verrucosum: observations under the light and scanning electron microscopes revealed that growth inhibition was accompanied by mycelial damage and cell lysis.


Assuntos
Antifúngicos/metabolismo , Quitina/metabolismo , Quitinases/metabolismo , Verticillium/enzimologia , Regiões Antárticas , Aspergillus/efeitos dos fármacos , Quitinases/química , Quitinases/isolamento & purificação , Cladosporium/efeitos dos fármacos , Meios de Cultura , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Mucor/efeitos dos fármacos , Penicillium/efeitos dos fármacos , Temperatura , Trichoderma/metabolismo , Verticillium/ultraestrutura
12.
J Biotechnol ; 80(3): 271-6, 2000 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-10949317

RESUMO

Extracellular pigment production by immobilised Monascus purpureus C322 has been studied in repeated-batch processes using different immobilising carriers such as Ca-alginate, polyurethane sponge, active carbon and pearlite. With Ca-alginate, pigment production was maximum (30.5 UA470 as process mean production, three batches) while the cell leakage was negligible (0.4 g 1(-1) free biomass) and the bead mechanical stability good; with this carrier, an extended repeated-batch fermentation (nine batches, 55 days) was carried out: the process pigment productivity was 3.87 UA470 day(-1).


Assuntos
Células Imobilizadas/metabolismo , Corantes de Alimentos , Pigmentos Biológicos/biossíntese , Leveduras/citologia , Leveduras/metabolismo , Alginatos , Biotecnologia/métodos , Fermentação
13.
J Biotechnol ; 83(3): 219-30, 2000 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-11051419

RESUMO

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.


Assuntos
Aspergillus/metabolismo , Succinatos/metabolismo , Aspergillus/crescimento & desenvolvimento , Meios de Cultura , Fermentação , Concentração de Íons de Hidrogênio , Cinética , Modelos Biológicos
14.
J Biomed Opt ; 6(3): 300-10, 2001 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-11516320

RESUMO

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.


Assuntos
Microscopia Confocal , Microscopia de Fluorescência , Animais , Imageamento Tridimensional , Microscopia de Polarização , Modelos Teóricos , Fótons , Análise Espectral
15.
Physiol Behav ; 30(4): 577-82, 1983 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-6878457

RESUMO

The possible involvement of cerebral DNA synthesis in the learning process was examined in rats injected intracerebrally with 3H thymidine. During the period of incorporation (4.5 hr) one rat was trained to an active avoidance task while a second animal was kept in the same experimental room. In comparison with control rats paired to learning animals, the concentration of PCA-soluble radioactivity and of radioactive DNA of the cerebral cortex increased in all animal groups, i.e., control rats paired to non-learning animals, learning rats and non-learning rats. No change occurred in liver. In the cerebral cortex the slope of the regression line obtained by plotting the concentration of radioactive DNA versus the concentration of PCA-soluble radioactivity was lower in learning rats than in the group of pooled control animals. A comparable effect was noted in the hippocampus. In non-learning animals a similar decrease was present in the cerebral cortex and in cerebellum. In addition, it was found that in learning animals the percent incorporation was inversely related to the total number of avoidances only in the cerebral cortex. In non-learning rats a similar inverse relationship was present in the cerebral cortex and in cerebellum. In the former region the regression line of learning rats was shifted upwards in comparison with the regression line of non-learning animals. These results are interpreted to indicate that the incorporation of 3H-thymidine into cerebral DNA is directly related to the level of stress and is increased by learning.


Assuntos
Aprendizagem da Esquiva/fisiologia , Encéfalo/metabolismo , DNA/biossíntese , Animais , Córtex Cerebral/metabolismo , Feminino , Fígado/metabolismo , Ratos , Ratos Endogâmicos , Timidina/metabolismo
16.
Int J Food Microbiol ; 52(1-2): 109-13, 1999 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-10573398

RESUMO

Sporangiospores were treated with high hydrostatic pressure and/or fungal chitinase in order to study the inhibition of germination and growth of the food spoiling mold Mucor plumbeus. Total fungal inhibition was obtained either at 4.0 kbar or by 10 U/ml of chitinase from Penicillium janthinellum. A pretreatment with 1 U/ml of the same chitinase reduced the pressure necessary to obtain complete spore inhibition to 3 kbar.


Assuntos
Quitinases/metabolismo , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Mucor/crescimento & desenvolvimento , Pressão Hidrostática , Microscopia Eletrônica de Varredura , Mucor/fisiologia , Penicillium/enzimologia , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/fisiologia , Chá/microbiologia
17.
J Biosci Bioeng ; 90(4): 381-6, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-16232876

RESUMO

COD (chemical oxygen demand) removal rate and efficiency of winery wastewater (WW) aerobic treatments were evaluated in an air-bubble column bioreactor using self-adapted microbial populations either free or immobilized on polyurethane particles and in a packed-bed bioreactor immobilized on Raschig rings. The bioreactors were fed continuously for up to 12 months using WW of different origins and with different pollution loads (COD range, 0.8-11.0 kg.m(-3)): the maximum loading rate was approx. 8.8 kg-COD m(-3).d(-1). The highest COD removal rate (6.6 kg.m(-3).d(-1)) was obtained with free activated sludge in the bubble column bioreactor; treatment efficiency and hydraulic retention time were >90% and approx. 0.8 d, respectively. The microbial populations in the three reactors were characterized.

18.
Bioresour Technol ; 79(3): 263-71, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11499580

RESUMO

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.


Assuntos
Fosfatos/química , Fósforo/química , Raízes de Plantas/microbiologia , Microbiologia do Solo , Células Imobilizadas/fisiologia , Conservação dos Recursos Naturais , Fermentação , Fertilizantes , Compostos Orgânicos , Solubilidade
19.
J Chem Technol Biotechnol ; 54(3): 283-90, 1992.
Artigo em Inglês | MEDLINE | ID: mdl-1368809

RESUMO

Fumaric acid production by Rhizopus arrhizus from commercial hydrolysates of corn starch (i.e. glucose molasses) was studied at different initial concentrations of glucose (S) and C:N ratios (R) by performing a 3(2) factorial experiment. By using the response surface methodology and statistical analysis, fumaric acid (YF) and mycelial biomass (YX) yields, as referred to the initial concentration of glucose and fumaric acid productivity (PF), were fitted to the only significant first-order effects of S and R with mean percentage errors ranging from 11 to 15%. The resulting empiric models were used to determine the optimal values of S (100-130 g dm-3) and R (150-210 g-atom C per g-atom N) associated with YF and PF varying in the ranges 40-49% and 7-8.5 g dm-3 day-1, respectively. After establishing the validity of these data at the 95% confidence level, an optimal operating condition (S = 120 g dm-3 and R = 150) was further tested using other substrates (i.e. glucose and acid or enzymatic hydrolysates of cassava, corn and potato flours). Statistically significant improvements in the fumaric acid yield and productivity were determined with respect to the predicted values. Since the highest values of YF and PF were obtained from the acid hydrolysates of the starch-based materials and such values were also found to be insensitive to the substrate used (at a probability level of 0.05), the above operating condition might be further employed to minimise fumaric acid production costs as a function of the feedstock used.


Assuntos
Meios de Cultura/metabolismo , Fumaratos/isolamento & purificação , Melaço , Rhizopus/metabolismo , Amido/metabolismo , Fermentação , Farinha , Fumaratos/metabolismo , Glucose/biossíntese , Hidrólise , Microbiologia Industrial/métodos , Malatos/metabolismo , Manihot , Modelos Biológicos , Solanum tuberosum
20.
Riv Biol ; 89(3): 493-6, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-9122587

RESUMO

Mucor circinelloides LU M40 and Penicillium aurantiogriseum P 35, characterized by extracellular beta-glucosidase activity on cyanogenic glycosides, hydrolyse amygdalin by a two-step reaction mechanism being the first step of hydrolysis, from amygdalin to prunasin, very rapid (15 min) and the second one, from prunasin to mandelonitrile, much slower (120 min).


Assuntos
Amigdalina/metabolismo , Antineoplásicos Fitogênicos/metabolismo , Fungos/metabolismo , Acetonitrilas/análise , Acetonitrilas/metabolismo , Amigdalina/análise , Cromatografia em Camada Fina , Meios de Cultura , Glicosídeo Hidrolases/metabolismo , Hidrólise , Modelos Químicos , Mucor/crescimento & desenvolvimento , Mucor/metabolismo , Nitrilas/análise , Nitrilas/metabolismo , Penicillium/crescimento & desenvolvimento , Penicillium/metabolismo , Fatores de Tempo
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