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1.
Acta Anaesthesiol Scand ; 57(9): 1154-60, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23909639

RESUMO

BACKGROUND: Post-operative pulmonary complications are associated with high mortality and graft loss in renal transplantation recipients. Left ventricular diastolic dysfunction is not uncommon in patients with chronic renal failure, including those with preserved left ventricular systolic function. The purpose of this study was to determine the relationship between left ventricular diastolic dysfunction and incidence of post-operative pulmonary edema in renal transplantation recipients with preserved left ventricular systolic function. METHODS: Pre-operative left ventricular function and incidence of pulmonary edema were retrospectively studied in 209 patients who underwent living-donor renal transplantation between January 2010 and October 2012. Left ventricular systolic and diastolic functions were evaluated by ejection fraction and E/E' ratio, retrospectively, using transthoracic echocardiography. Pulmonary edema was defined by evidence of pulmonary congestion on the chest X-ray together with PaO2 /FiO2 ratio < 300 mmHg. RESULTS: Eleven out of 190 (5.8%) renal transplantation patients with preserved left ventricular systolic function developed post-operative pulmonary edema. Patients with pulmonary edema had a significantly higher geometric mean (95% confidence interval) of E/E' ratio than those without pulmonary edema [17.8 (14.1-22.5) vs. 11.1 (10.6-11.7), P = 0.001]. CONCLUSION: Pre-operative left ventricular diastolic dysfunction correlated with the development of post-operative pulmonary edema in renal transplantation recipients. Meticulous intraoperative volume therapy is important to avoid post-operative pulmonary edema in such patients.


Assuntos
Transplante de Rim/efeitos adversos , Edema Pulmonar/fisiopatologia , Disfunção Ventricular Esquerda/fisiopatologia , Adulto , Idoso , Anestesia Geral , Ecocardiografia , Feminino , Testes de Função Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/fisiopatologia , Edema Pulmonar/complicações , Estudos Retrospectivos , Volume Sistólico/fisiologia , Falha de Tratamento , Resultado do Tratamento , Disfunção Ventricular Esquerda/etiologia
2.
J Appl Microbiol ; 105(3): 741-51, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18355232

RESUMO

AIMS: (i) Quantitative and qualitative analyses of photosynthetic metabolites of Chlorella sorokiniana and elucidation of the mechanism of their utilization by algal symbionts. (ii) Development of artificial medium that imitates photoautotroph-heterotroph interaction and investigation of its suitability for isolation of novel microbes from the environment. METHODS AND RESULTS: Various components, including free dissolved carbohydrates, nitrogenous compounds and vitamin, were detected and together contributed 11.1% (as carbon content) of the total photosynthetic metabolites in the medium. Utilization of these photosynthetic metabolites in algal culture broth by algal symbionts was studied. Many symbionts showed specific utilization patterns. A novel artificial extracellular released organic carbon medium, which imitated the nutritional conditions surrounding algae, was developed based on the pattern of utilization of the algal metabolites by the symbiotic heterotrophs. About 42.9% of the isolates were closely related to photoautotrophic-dependent and oligotrophic bacteria. CONCLUSIONS: With the novel artificial medium, it was possible to selectively isolate some bacterial strains. SIGNIFICANT AND IMPACT OF THE STUDY: Synthetic bacterial growth medium is an important and basic tool for bacterial isolation from environmental samples. The current study shows that preferential separation of typical bacterial subset can be achieved by using artificial medium that mimics photosynthetic metabolites.


Assuntos
Bactérias/metabolismo , Chlorella/metabolismo , Microbiologia da Água , Animais , Técnicas Bacteriológicas , Meios de Cultura , Fotossíntese , Simbiose
3.
Lett Appl Microbiol ; 42(5): 538-43, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16620216

RESUMO

AIMS: To investigate the chemical characterization of the mucilage sheath produced by Chlorella sorokiniana. METHODS AND RESULTS: Algal mucilage sheath was hydrolysed with NaOH, containing EDTA. The purity of the hydrolysed sheath was determined by an ATP assay. The composition of polysaccharide in the sheath was investigated by high-performance anion-exchange chromatography with pulsed amperometric detection. Sucrose, galacturonic acid, xylitol, inositol, ribose, mannose, arabinose, galactose, rhamnose and fructose were detected in the sheath as sugar components. Magnesium was detected in the sheath as a divalent cation using inductively coupled argon plasma. The sheath matrix also contained protein. CONCLUSIONS: It appears that the sheath is composed of sugars and metals. Mucilage sheath contains many kinds of saccharides that are produced as photosynthetic metabolites and divalent cations that are contained in the culture medium. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report on chemical characterization of the sheath matrix produced by C. sorokiniana.


Assuntos
Chlorella/química , Polissacarídeos/química , Proteínas de Algas/análise , Carboidratos/análise , Chlorella/metabolismo , Cromatografia Líquida de Alta Pressão , Magnésio/análise
4.
Clin Nephrol ; 63(6): 481-6, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15960151

RESUMO

AIMS: The calcium-sensing receptor (CaSR) regulates the extracellular calcium level, mainly by controlling parathyroid hormon secretion and renal calcium reabsorption. In gain-of-function CaSR mutations, the genetic abnormalities increase CaSR activity leading to the development of such clinical manifestations as hypercalciuric hypocalcemia and hypoparathyroidism. We report a Japanese case of CaSR gain-of-function mutation and represent a therapeutic intervention based on the functional characteristics of CaSR in renal tubule. METHODS AND RESULTS (CASE): DNA sequence analysis revealed a heterozygous G to T mutation identified in a 12-year-old Japanese girl presenting with sporadic onset of hypercalciuric hypocalcemia and hypoparathyroidism. The mutation is located in the N-terminal extracellular domain of the CaSR gene, one of the most important parts for the three-dimensional construction of the receptor, resulting in the substitution of phenylalanine for cysteine at amino acid 131 (C131F) in exon 3. Based on the diagnosis of the gain-of-function mutation in the CaSR, oral hydrochlorothiazide administration and supplemental hydration were started in addition to calcium supplementation. The combination therapy of thiazide and supplemental hydration markedly reduced both renal calcium excretion and urinary calcium concentration from 0.4-0.7 to less than 0.1 mg/mg (urinary calcium/creatinine ratio) and from 10-15 to 3-5 mg/dl (urinary calcium concentration), respectively. This therapy stopped the progression of renal calcification during the follow-up period. CONCLUSION: Supplemental hydration should be considered essential for the following reasons: (1) calcium supplementation activates the CaSR in the kidney and suppresses renal urinary concentrating ability, (2) the thiazide has a diuretic effect, (3) as calcium supplementation increases renal calcium excretion, the supplemental hydration decreases urinary calcium concentration by increasing urinary volume, thereby diminishing the risk of intratubular crystallization of calcium ion.


Assuntos
DNA/genética , Hipocalcemia/genética , Hipoparatireoidismo/genética , Nefropatias/prevenção & controle , Mutação , Receptores de Detecção de Cálcio/genética , Água/administração & dosagem , Administração Oral , Cálcio/urina , Criança , Análise Mutacional de DNA , Líquido Extracelular/metabolismo , Feminino , Seguimentos , Humanos , Hidroclorotiazida/administração & dosagem , Hidroclorotiazida/análogos & derivados , Hidroclorotiazida/uso terapêutico , Hipocalcemia/complicações , Hipocalcemia/metabolismo , Hipoparatireoidismo/complicações , Hipoparatireoidismo/metabolismo , Nefropatias/etiologia , Reação em Cadeia da Polimerase , Receptores de Detecção de Cálcio/metabolismo
5.
Neurology ; 59(7): 1102-4, 2002 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-12370475

RESUMO

The authors describe a patient with dopa-responsive dystonia who developed neuroleptic malignant syndrome with prolonged catatonia following treatment with neuroleptic agents. Use of these agents probably expanded the patient's neuronal dysfunction beyond the nigrostriatal system to involve multiple dopaminergic systems. Electroconvulsive treatment alleviated the prolonged catatonia.


Assuntos
Catatonia/fisiopatologia , Distonia/tratamento farmacológico , Levodopa/uso terapêutico , Síndrome Maligna Neuroléptica/fisiopatologia , Adulto , Catatonia/diagnóstico , Catatonia/terapia , Distonia/enzimologia , Distonia/genética , Eletroencefalografia/efeitos dos fármacos , Eletroencefalografia/estatística & dados numéricos , Feminino , GTP Cicloidrolase/genética , Humanos , Síndrome Maligna Neuroléptica/diagnóstico , Síndrome Maligna Neuroléptica/terapia
6.
Anal Chem ; 73(21): 5310-5, 2001 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-11721934

RESUMO

A platinum electrode was coated with polyelectrolyte multilayer (PEM) films to prepare an amperometric hydrogen peroxide sensor which can be used in the presence of possible interferences such as ascorbic acid, uric acid, and acetaminophen. The PEM films were prepared on the surface of a Pt disk electrode by an alternate deposition of polycation and polyanion from the aqueous solutions through electrostatic force of attraction. The Pt electrodes coated with a poly(allylamine)/poly(vinyl sulfate) or poly(allylamine)/poly(styrenesulfonate) film were used successfully for detecting H2O2 selectively in the presence of the possible interfering agents. It was suggested that H2O2 can diffuse into the PEM film smoothly while the ascorbic acid, uric acid, and acetaminophen cannot penetrate the film by a size exclusion mechanism. On the other hand, the electrodes coated with PEM films containing poly(ethyleneimine) or poly(diallyldimethylammonium chloride) were not useful for the selective determination of H2O2. The results were rationalized based on the different permeability of the films due to the different molecular density or packing in the PEM films. The PEM film-coated electrode was useful for constructing glucose biosensors by coupling with glucose oxidase.


Assuntos
Técnicas Biossensoriais/métodos , Peróxido de Hidrogênio/análise , Poliaminas/análise , Acetaminofen/análise , Ácido Ascórbico/análise , Eletroquímica , Eletrodos , Polieletrólitos , Ácido Úrico/análise
7.
Biotechnol Bioeng ; 74(6): 466-75, 2001 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-11494213

RESUMO

Microalgal photosynthesis requires appropriate culture medium temperatures to achieve high photosynthetic performance and to maintain production of a high-quality biomass product. Enclosed systems, such as our conical, helical tubular photobioreactor (HTP), can accomplish high photosynthetic efficiency and the small amount of culture medium used by these systems means that the culture medium temperature may be effectively controlled. On the other hand, because a high ratio of surface area to culture medium volume leads to rapid heating under the illumination condition and substantial heat loss at night, maintaining a suitable culture medium temperature is necessary to achieve efficient, commercially practical biomass production. In order to predict changes in the culture medium temperature caused by changes in solar irradiance and ambient temperature, it is necessary to understand the heat balance within the photobioreactor. We therefore investigated the heat balance in three major parts (photostage, degasser, and helical heat exchanger) of our conical HTP, analyzed the time-dependent changes in medium temperature at various room temperatures and radiant energy inputs, and predicted changes in the culture medium temperature based on the characteristics of heat transfer among the three parts. Using this model, the predicted changes in culture medium temperature were very similar to the changes observed experimentally in the laboratory and under field conditions. This means that by calculating the time-dependent changes in the culture medium temperature, based on measurements of solar energy input and ambient temperature, we should be able to estimate the energy required to maintain the culture medium temperature within a range where photosynthetic performance of microalgae is high.


Assuntos
Reatores Biológicos , Biotecnologia/instrumentação , Biotecnologia/métodos , Técnicas de Cultura de Células/instrumentação , Técnicas de Cultura de Células/métodos , Luz , Eucariotos/fisiologia , Fotossíntese/fisiologia , Temperatura , Fatores de Tempo
8.
Anal Chem ; 73(14): 3392-9, 2001 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-11476240

RESUMO

A flow-based immunoassay that uses microspheres as the solid phase accomplished the theoretical limit of detectability achievable with the antibody. An equilibrated mixture of anti-estriol monoclonal antibody and estriol was briefly exposed to a bead pack containing immobilized estriol in a flow cell. A small portion of free antibody was separated rapidly from the mixture by binding it to immobilized hormone, but the antibody-hormone complex was kinetically excluded from binding. This rapid separation prevented shift in the equilibrium of the liquid phase binding. Signals were generated by labeling the separated antibodies on the beads with a Cy5-conjugated antispecies secondary antibody. By labeling after the separation step, perturbing the liquid-phase or solid-phase binding was prevented. This assay allowed the reduction of the concentration of primary antibody by continuously accumulating free antibody onto the beads prior to quantification and, thus, offered ideal conditions to achieve theoretical limits of detectability. The optimum achievable dynamic range of this immunoassay was 4-300 pM. Because the proportion of free anti-estriol antibody in the mixture was controlled by the Kd of the antibody-estriol interaction, when the concentration of the antibody was below the Kd, the smallest detectable estriol concentration approached the theoretical limit of detectability achievable with this antibody.


Assuntos
Estriol/análise , Imunoensaio/métodos , Anticorpos Monoclonais/imunologia , Antígenos/imunologia , Estriol/imunologia , Cinética , Microesferas , Sensibilidade e Especificidade
9.
Biotechnol Bioeng ; 74(2): 136-44, 2001 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-11370002

RESUMO

The characteristics of the flow of culture medium significantly affects the photosynthetic productivity of bioreactors incorporating microalgae. Therefore, in order to optimize the performance of a conical helical tubular photobioreactor (CHTP) designed to be useful in practical applications, we characterized the flow pattern of the culture medium through the reactor. The effects of medium flow conditions on the photosynthetic productivity of Chlorella sp. were investigated using several different CHTP units with 0.50-m2 installation areas which were designed to vary the direction and rate of flow driven by airlift. In addition, the performance of two- and four-unit systems constructed by combining individual CHTP units was evaluated. We found that when medium flowed from the bottom to the top of the photostage, it exhibited smoother flow of culture medium than when flowing from top to bottom, which led to higher photosynthetic productivity by the former. Consistent with theoretical calculations, varying the lengths of vertical flow passages caused flow rates to vary, and higher flow rates meant smoother circulation of medium and better photosynthetic performance. Flow of medium through a four-unit CHTP system was similar to that in single units, enabling a photosynthetic productivity of 31.0 g-dry biomass per m2-installation area per day to be achieved, which corresponded to a photosynthetic efficiency of 7.50% (photosynthetically active radiation (PAR; 400-700 nm)). This high photosynthetic performance was possible because smoother medium flow attained in single units was also attained in the four-unit system.


Assuntos
Reatores Biológicos , Chlorella/fisiologia , Microbiologia Industrial/instrumentação , Dióxido de Carbono/metabolismo , Meios de Cultura , Microbiologia Industrial/métodos , Fotossíntese
10.
Nihon Rinsho ; 58(10): 2072-7, 2000 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-11068449

RESUMO

Pallidotomy has recently regained acceptance as an effective treatment for Parkinson's disease. From our 50 cases of unilateral pallidotomy and 10 cases of staged bilateral pallidotomy, details and indications of the procedure is described. The unilateral pallidotomy is quite effective for L-dopa induced dyskinesia, which usually completely disappears soon after the operation. The effect is long-lasting. When on-off phenomenon exists, unilateral pallidotomy improves off-stage rigidity or akinesia. Symptoms during on-stage are not changed. Indications of pallidotomy is that(1) L-dopa induced dyskinesia, and(2) on-off phenomenon. Bilateral pallidotomy, even by staged one, causes severe drooling, or speech disturbance(the volume of the voice decreases and the articulation worsens), and is not recommended. Vim thalamotomy is, on the other hand, the established treatment for tremor of Parkinson's disease or of essential tremor. The effect is long-lasting. Rigidity or akinesia is not expected to be improved so much.


Assuntos
Globo Pálido/cirurgia , Doença de Parkinson/cirurgia , Técnicas Estereotáxicas , Tálamo/cirurgia , Discinesia Induzida por Medicamentos/cirurgia , Humanos , Levodopa/efeitos adversos , Rigidez Muscular/etiologia , Rigidez Muscular/cirurgia , Doença de Parkinson/complicações , Tremor/etiologia , Tremor/cirurgia
11.
Mutat Res ; 471(1-2): 127-34, 2000 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-11080668

RESUMO

We used bacterial mutation assays to assess the mutagenic and co-mutagenic effects of power frequency magnetic fields (MF). For the former, we exposed four strains of Salmonella typhimurium (TA98, TA100, TA1535, TA1537) and two strains of Escherichia coli (WP2 uvrA, WP2 uvrA/pKM101) to 50Hz, 14mT circularly polarized MF for 48h. All results were negative. For the latter, we treated S. typhimurium (TA98, TA100) and E. coli (WP2 uvrA, WP2 uvrA/pKM101) cells with eight model mutagens (N-ethyl-N'-nitro-N-nitrosoguanidine, 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide, 4-nitroquinoline-N-oxide, 2-aminoanthracene, N(4)-aminocytidine, t-butyl hydroperoxide, cumen hydroperoxide, and acridine orange) with and without the MF. The MF induced no significant, reproducible enhancement of mutagenicity. We also investigated the effect of MF on mutagenicity and co-mutagenicity of fluorescent light (ca. 900lx for 30min) with and without acridine orange on the most sensitive tester strain, E. coli WP2 uvrA/pKM101. Again, we observed no significant difference between the mutation rates induced with and without MF. Thus, a 50Hz, 14mT circularly polarized MF had no detectable mutagenic or co-mutagenic potential in bacterial tester strains under our experimental conditions. Nevertheless, some evidence supporting a mutagenic effect for power frequency MFs does exist; we discuss the potential mechanisms of such an effect in light of the present study and studies done by others.


Assuntos
Bactérias/genética , Magnetismo/efeitos adversos , Mutagênese/efeitos dos fármacos , Testes de Mutagenicidade , Cocarcinogênese , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Fluorescência , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/enzimologia , Mutagênicos/toxicidade , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética
12.
Biotechnol Bioeng ; 70(4): 464-6, 2000 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-11005929

RESUMO

Electrolytic cultivation was applied to Leptospirillum ferrooxidans strains P3A and CF27, which use ferrous iron to respire aerobically. Ferrous iron was supplied to the bacteria by intermittent electrolytic reduction of ferric iron as electron shuttle using an electrode. The yield of L. ferrooxidans and strain CF27 reached 20- and 50-fold, respectively, higher density than were achievable yields without electrolysis. The time required to obtain high density depended not on the growth ratio, but rather on the original growth rate of each strain.


Assuntos
Eletrólise/métodos , Bactérias Gram-Negativas/metabolismo , Ferro/metabolismo , Biotecnologia/métodos , Divisão Celular , Oxirredução , Thiobacillus/metabolismo
13.
Appl Biochem Biotechnol ; 87(3): 203-18, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10982230

RESUMO

The batch culture of a newly isolated strain of a green microalga, Chlorella sorokiniana, was carried out using a conical helical tubular photobioreactor. The isolate was capable of good growth at 40 degrees C under an airstream enriched with 10% CO2. The maximum photosynthetic productivity was 34.4 g of dry biomass/(m2 of installation area x d) (12-h light/12-h dark cycle) when the cells were illuminated with an average photosynthetic photon flux density (photosynthetically active radiation ([PAR] 400-700 nm) simulating the outdoors in central Japan (0.980 mmol photons/[m2 x s]). This corresponded to a photosynthetic efficiency of 8.67% (PAR), which was defined as the percentage of the light energy recovered as biomass (394 kJ/[reactor x d]) to the total light energy received (4545 kJ/[reactor x d]). A similarly high photosynthetic efficiency (8.12% [PAR]) was also attained in the combined presence of 10% CO2, 100 ppm of NO, and 25 ppm of SO2. Moreover, good photosynthetic productivity was also obtained under high temperature and high light intensity conditions (maximum temperature, 46.5 degrees C; 1.737 mmol photons/[m2 x s]), when simulating the strong irradiance of the midday summer sun. This strain thus appears well suited for practical application for converting CO2 present in the stack gases emitted by thermal power plants and should be feasible even during the hot summer weather.


Assuntos
Chlorella/metabolismo , Fotossíntese , Sequência de Bases , Reatores Biológicos , Dióxido de Carbono/metabolismo , Chlorella/classificação , Chlorella/genética , Concentração de Íons de Hidrogênio , Luz , Microscopia Eletrônica , Dados de Sequência Molecular , Óxido Nítrico/metabolismo , Análise de Sequência de DNA , Dióxido de Enxofre/metabolismo , Temperatura , Fatores de Tempo
14.
Radiat Res ; 154(2): 208-16, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10931694

RESUMO

Escherichia coli K12 was used as a model system to determine whether ELF magnetic fields (MFs) are a general stress factor. The cells were exposed to ELF MFs (5-100 Hz) at a maximum intensity of 14 mT r. m.s. for circularly polarized MFs and 10 mT r.m.s. for vertically polarized MFs. The response of the cells to the MFs was estimated from the change in protein synthesis by using 2D PAGE. Approximately 1,000 proteins were separated on the 2D gels. The stress-responsive proteins such as CH10, DNAK, CH60, RECA, USPA, K6P1 and SODM were identified from the SWISS-2DPAGE database on the 2D gels. These proteins respond to most stress factors, including temperature change, chemical compounds, heavy metals, and nutrients. When the bacterial cells were exposed to each MF at 5-100 Hz under aerobic conditions (6.5 h) or at 50 Hz under anaerobic conditions (16 h) at the maximum intensity (7.8 to 14 mT r.m.s.), no reproducible changes were observed in the 2D gels. Changes in protein synthesis were detected by 2D PAGE with exposure to heat shock (50 degrees C for 30 min) or under anaerobic conditions (no bubbling for 16 h). Increases in the levels of synthesis of the stress proteins were observed in heat-shocked cells (CH60, CH10, HTPG, DNAK, HSLV, IBPA and some unidentified proteins) and in cells grown under anaerobic conditions (DNAK, PFLB, RECA, USPA and many unidentified proteins). These results suggest that 2D PAGE is sufficient to detect cell responses to environmental stress. The high-intensity ELF MFs (14 mT at power frequency) did not act as a general stress factor.


Assuntos
Campos Eletromagnéticos , Escherichia coli/efeitos da radiação , Proteínas de Choque Térmico/biossíntese , Aerobiose , Anaerobiose , Eletroforese em Gel Bidimensional , Escherichia coli/genética , Escherichia coli/metabolismo , Nível de Efeito Adverso não Observado , Temperatura
15.
Biotechnol Bioeng ; 69(6): 693-8, 2000 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-10918145

RESUMO

As photosynthetic efficiencies are relatively high at irradiation levels of <500 micromol m(-2) s(-1), photosynthetic productivity could be increased by redistributing strong light over a larger photo-receiving area using conical, helical, tubular photobioreactors (HTP). When Chlorella were exposed to light irradiation of 980 micromol m(-2) s(-1), the ratio of productivities was 1.00:1.13:1.23:1.66 for conical HTPs with cone angles of 180 degrees (flat type), 120 degrees, 90 degrees, and 60 degrees, respectively. This suggests that photo-redistribution technology is a highly effective and convenient approach for increasing the photosynthetic productivity of microalgae.


Assuntos
Reatores Biológicos , Biotecnologia/métodos , Chlorella/metabolismo , Fotossíntese , Biotecnologia/instrumentação , Chlorella/fisiologia , Luz , Modelos Biológicos
16.
Appl Environ Microbiol ; 66(2): 816-9, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10653756

RESUMO

To improve the cooperative removal of nitrogen by Nitrosomonas europaea and Paracoccus denitrificans, we controlled their distribution in a tubular gel. When ethanol was supplied inside the tubular gel as an electron donor, their distributions overlapped in the external region of the gel. By changing the electron donor from ethanol to gaseous hydrogen, the distribution of P. denitrificans shifted to the inside of the tube and was separated from that of N. europaea. The separation resulted in an increase of the oxidation rate of ammonia by 25%.


Assuntos
Reatores Biológicos , Nitrogênio/metabolismo , Nitrosomonas/crescimento & desenvolvimento , Paracoccus denitrificans/crescimento & desenvolvimento , Amônia/metabolismo , Células Imobilizadas , Géis , Hidrogênio/metabolismo , Microscopia de Fluorescência , Nitrosomonas/metabolismo , Oxirredução , Paracoccus denitrificans/metabolismo
17.
Biotechnol Bioeng ; 67(1): 80-6, 2000 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-10581438

RESUMO

Packed gel envelopes were constructed as simple, compact reactors for removing nitrogen from wastewater. Each packed gel envelope consisted of two plate gels with a spacer in between. Nitrosomonas europaea and Paracoccus denitrificans were co-immobilized in the plate gels, and ethanol, serving as an electron donor for denitrification, was injected into the internal spaces of the envelopes. The external surfaces of the envelopes were in contact with ammonia-containing wastewater; the N. europaea present in the gels oxidized the ammonia to nitrite aerobically. On the other hand, the internal surfaces of the envelopes were in contact with the ethanol solution, which P. denitrificans used to reduce the nitrite to nitrogen gas anaerobically. In this way, the reactor using the packed gel envelopes removed ammonia from wastewater in a single step. When artificial wastewater containing 200 mg-N/L was treated using the reactor using eight envelopes, the ammonia was removed by the reactor without accumulating nitrite or ethanol. This simple system exhibited high rates of nitrification (ammonia to nitrite; 1.9 kg-N/day for 1m(3) of reactor volume) and nitrogen removal (ammonia to nitrogen gas; 1.6 kg-N/day). It is presumed that these high rates were achieved as a consequence of cooperation between the N. europaea and P. denitrificans present in the gels and the efficient uptake and exhaust of gases leading to the smooth conversion of ammonia to nitrogen gas.


Assuntos
Reatores Biológicos , Nitrogênio/metabolismo , Nitrosomonas/metabolismo , Paracoccus denitrificans/metabolismo , Amônia/isolamento & purificação , Amônia/metabolismo , Biotecnologia , Géis , Nitrogênio/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/metabolismo
18.
J Biosci Bioeng ; 90(6): 654-60, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-16232927

RESUMO

Tubular gel reactors containing Nitrosomonas europaea and Paracoccus denitrificans, which remove nitrogen from solutions through a process of nitrification and denitrification, require oxygen for ammonia oxidation, the first and rate-limiting step in the process. To accelerate ammonia oxidation, high concentrations of oxygen were applied to the reactors instead of air. Although a 50% O2:N2 gas mixture and pure oxygen were both toxic to free N. europaea cells, they actually accelerated ammonia oxidation by N. europaea immobilized within the tubular gel. Indeed, the rate of ammonia oxidation by a tube exposed to pure oxygen was twice that of one exposed to 20% O2. When the distribution of N. europaea cells within the tubes was investigated using a fluorescently-labeled antibody, colonies were found on the external surface of the tube exposed to 20% O2, but were located at a depth of 120-300 microm from the external surface in the case of the tube exposed to pure oxygen. The region between the external surface of the gel and the colonies apparently acted as a barrier, reducing the diffusion of oxygen and thus protecting the cells from oxygen cytotoxicity.

19.
Biosens Bioelectron ; 15(11-12): 623-8, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11213223

RESUMO

Spatially ordered multilayer thin films containing anti-fluoresceinisothiocyanate (anti-FITC) were prepared on the surface of a quartz slide to study the binding properties of the multilayer films. A quartz slide was treated in solutions of avidin and biotin-labeled anti-FITC alternately and repeatedly to form multilayer thin films through a strong affinity between avidin and biotin. A spectrophotometric study revealed explicitly that the thin films thus prepared consisted of alternate monomolecular layers of avidin and biotin-labeled anti-FITC. The antibody retained its binding activity to antigen in the multilayer thin film, though the antigen could not access the antibody embedded deep in the multilayer film. Only the outermost four or five layers of antibody were involved in the binding of antigen.


Assuntos
Reações Antígeno-Anticorpo , Técnicas Biossensoriais , Fluoresceína-5-Isotiocianato , Espectrofotometria Ultravioleta
20.
Biotechnol Bioeng ; 64(6): 716-21, 1999 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-10417221

RESUMO

In this study, we demonstrated that the period of logarithmic growth for Thiobacillus ferrooxidans could be extended when optimal conditions for cell growth were maintained using potential controlled electrochemical cultivation with sufficient aeration. The optimal pH and Fe(II) concentration for the electrolytic cultivation were determined to be 2.0 and 150 mM, respectively. When the potential was set to 0.0V vs Ag/AgCl, the Pt electrode reduced Fe(III) to Fe(II) with an efficiency of 95%. A porous glass microbubble generator was used to maintain adequate levels of dissolved oxygen, which was the electron acceptor for T. ferrooxidans when the cell density in the medium was high. Under these conditions, cells at an initial density of 10(7) cells/mL grew logarithmically for 4days until the cell density was 4 x 10(9) cells/mL. This corresponded to a period of logarithmic growth that was 3 times longer than was observed in batch cultures without electrolysis. In addition, the final cell density reached 10(10) cells/mL after 6 days of electrochemical cultivation, which was a 50-fold increase over conventional batch culture. Under conditions of increasing cell density, potentiostatic electrolysis made it possible to remove Fe(III), which causes product inhibition, at an increasing rate and to correspondingly increase the production rate of Fe(II), which is the electron donor for T. ferrooxidans. Thus, our cultivation system provides a sufficient supply of electron donor and acceptor for T. ferrooxidans, thereby elongating the period of logarithmic growth and producing very high cell densities.


Assuntos
Eletroquímica/métodos , Ferro/metabolismo , Thiobacillus/crescimento & desenvolvimento , Thiobacillus/metabolismo , Meios de Cultura , Eletrodos , Ferro/química , Oxirredução , Oxigênio/química
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