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1.
Artigo em Inglês | MEDLINE | ID: mdl-26736744

RESUMO

To enable precise detection of mental and physical states of users in a daily life, we have been developing an eyewear to measure eye and body movement in a unrestricted way. The horizontal and vertical EOG (electrooculogram) signals are measured and amplified with three metal dry electrodes placed near nasion and both sides of rhinion, of which positions correspond to the bridge and nose pads of eyewear, respectively. The user's mental states like drowsiness, sleepiness, fatigue, or interest to objects can be identified by the movements and blinking of the eyes extracted from the measured EOG. And the six-axis motion sensor (three-axis accelerometer and three-axis gyroscope) mounted in the eyewear measures the body motion. As the sensor located near the head is on the body axis, this eyewear is suitable to measure user's movement or shift of center of gravity during physical exercise with a high precision. The measured signals are used to extract various events of eye and body movement by the mounted microcontroller chip, or can be transmitted to the external devices via Bluetooth communication. This device can enable you to look into "yourself", as well as outer scenes. In this presentation, the outline of the eyewear is introduced and some possible applications are shown.


Assuntos
Eletroculografia , Movimentos Oculares/fisiologia , Monitorização Fisiológica , Movimento/fisiologia , Piscadela , Eletroculografia/instrumentação , Eletroculografia/métodos , Humanos , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos , Fases do Sono
2.
Appl Microbiol Biotechnol ; 70(3): 346-57, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16283296

RESUMO

To construct yeast strains showing tolerance to high salt concentration stress, we analyzed the transcriptional response to high NaCl concentration stress in the yeast Saccharomyces cerevisiae using DNA microarray and compared between two yeast strains, a laboratory strain and a brewing one, which is known as a stress-tolerant strain. Gene expression dynamically changed following the addition of NaCl in both yeast strains, but the degree of change in the gene expression level in the laboratory strain was larger than that in the brewing strain. The response of gene expression to the low NaCl concentration stress was faster than that to the high NaCl concentration stress in both strains. Expressions of the genes encoding enzymes involved in carbohydrate metabolism and energy production in both strains or amino acid metabolism in the brewing strain were increased under high NaCl concentration conditions. Moreover, the genes encoding sodium ion efflux pump and copper metallothionein proteins were more highly expressed in the brewing strain than in the laboratory strain. According to the results of transcriptome analysis, candidate genes for the creation of stress-tolerant strain were selected, and the effect of overexpression of candidate genes on the tolerance to high NaCl concentration stress was evaluated. Overexpression of the GPD1 gene encoding glycerol-3-phosphate dehydrogenase, ENA1 encoding sodium ion efflux protein, and CUP1 encoding copper metallothionein conferred high salt stress tolerance to yeast cells, and our selection of candidate genes for the creation of stress-tolerant yeast strains based on the transcriptome data was validated.


Assuntos
Resposta ao Choque Térmico , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Regulação Fúngica da Expressão Gênica , Laboratórios , Oryza/metabolismo , Saccharomyces cerevisiae/classificação , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/fisiologia , Proteínas de Saccharomyces cerevisiae/genética , Transcrição Gênica , Vinho/microbiologia
3.
Bioprocess Biosyst Eng ; 25(5): 291-8, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14505173

RESUMO

An experimental method for metabolic control analysis (MCA) was applied to the investigation of a metabolic network of glutamate production by Corynebacterium glutamicum. A metabolic reaction (MR) model was constructed and used for flux distribution analysis (MFA). The flux distribution at a key branch point, 2-oxoglutarate, was investigated in detail. Activities of isocitrate dehydrogenase (ICDH), glutamate dehydrogenase (GDH), and 2-oxoglutarate dehydrogenase complex (ODHC) around this the branch point were changed, using two genetically engineered strains (one with enhanced ICDH activity and the other with enhanced GDH activity) and by controlling environmental conditions (i.e. biotin-deficient conditions). The mole flux distribution was determined by an MR model, and the effects of the changes in the enzyme activities on the mole flux distribution were compared. Even though both GDH and ICDH activities were enhanced, the mole flux distribution was not significantly changed. When the ODHC activity was attenuated, the flux through ODHC decreased, and glutamate production was markedly increased. The flux control coefficients of the above three enzymes for glutamate production were determined based on changes in enzyme activities and the mole flux distributions. It was found that the factor with greatest impact on glutamate production in the metabolic network was obtained by attenuation of ODHC activity.

4.
Nihon Kokyuki Gakkai Zasshi ; 40(6): 473-7, 2002 Jun.
Artigo em Japonês | MEDLINE | ID: mdl-12325331

RESUMO

The incidences of cardiovascular and cerebrovascular diseases are reportedly higher in patients with obstructive sleep apnea (OSA) than in OSA-free subjects, though the mechanism remains unknown. Recently, the contribution of activated platelets to a number of pathological conditions such as stroke or ischemic heart disease has been suggested. We hypothesized that the expression of activated platelet markers resulting from OSA might be higher than in healthy subjects. By flow cytometry using monoclonal antibodies, we measured two such markers, PAC-1 and CD 62 P, in OSA patients and healthy subjects. Twelve healthy men (age, 52.7 +/- 12.8 y/o; and body mass index (BMI), 22.2 +/- 16.1 kg/m2; mean +/- S.D.) and 20 male patients with OSA (age, 50 +/- 7.96 y/o; BMI, 28.1 +/- 3.3 kg/m2; apnea hypopnea index (AHI), 38.2 +/- 21.2 times/hr; and lowest SpO2, 75.6 +/- 11.3%) were enrolled in this study. PAC-1 expression was significantly higher in OSA patients (65.1 +/- 17.8%) than in healthy subjects (16.8 +/- 7.4%), as was CD 62 P expression (8.5 +/- 8.8% vs. 0.88 +/- 0.57%). The increase in PAC-1 expression was correlated with AHI and the arousal index. These findings suggest that activated platelet markers could be good indicators for untreated OSA.


Assuntos
Selectina-P/sangue , Ativação Plaquetária , Proteínas Tirosina Fosfatases/sangue , Apneia Obstrutiva do Sono/sangue , Adulto , Biomarcadores/sangue , Doenças Cardiovasculares/etiologia , Transtornos Cerebrovasculares/etiologia , Fosfatase 2 de Especificidade Dupla , Citometria de Fluxo , Humanos , Masculino , Pessoa de Meia-Idade , Proteína Fosfatase 2 , Apneia Obstrutiva do Sono/complicações , Apneia Obstrutiva do Sono/diagnóstico
5.
Med Sci Sports Exerc ; 33(6): 901-6, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11404654

RESUMO

PURPOSE: The effects of aging on muscle metabolism and oxygenation have not yet been elucidated. We evaluated the effects of aging on energy metabolism and oxygenation in sedentary healthy subjects by simultaneously measuring 31P-magnetic resonance spectroscopy (MRS) and near-infrared spectroscopy (NIRS). METHODS: Nine young (28.1 +/- 5.0 yr) and nine older (61.4 +/- 4.6 yr) healthy subjects were studied. The 31P-MR spectrum was obtained every 15 s during and after hand gripping exercise. Intracellular pH (pHi) and PCr/(PCr+Pi) [PCr: phosphocreatine, Pi: inorganic phosphate] were calculated as an index of energy metabolism. The time constant of the PCr/(PCr+Pi) recovery (tau PCr) was calculated. With NIRS, we evaluated the recovery rates of oxygenated (RHbO2) and deoxygenated hemoglobin (RHb) during the initial 10 s of recovery. RESULTS: The PCr/(PCr+Pi) and pHi at rest and at completion of the exercise and tau PCr did not differ between young and older subjects. However, RHbO2 and RHb were significantly slower in older subjects than in young subjects. CONCLUSIONS: The results suggest that muscle energy metabolism in the forearm muscle was not affected by aging. The slower RHbO2 and RHb in older subjects suggested impaired O2 supply, which was probably due to impaired peripheral circulation caused by the process of aging.


Assuntos
Envelhecimento/fisiologia , Metabolismo Energético , Músculo Esquelético/fisiologia , Oxigênio/metabolismo , Adulto , Idoso , Feminino , Antebraço/irrigação sanguínea , Antebraço/fisiologia , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Isótopos de Fósforo , Espectroscopia de Luz Próxima ao Infravermelho
6.
Biotechnol Bioeng ; 74(2): 116-24, 2001 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-11370000

RESUMO

A novel multivariable control strategy is developed for alcohol (ethanol and n-pentanol) concentrations in the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), P(HB-co-HV), a biodegradable polymer by Paracoccus denitrificans ATCC 1774. This controller, which is developed to control the mole fraction of P(HB-co-HV), consists of two parts: one is for ethanol concentration control and the other is for mole fraction control, based on the concept of metabolic flux distribution control. A simple metabolic reaction (MR) model is constructed for flux distribution analysis. The relationship between mole ratio of specific consumption rate of the two alcohols (ethanol and n-pentanol) and the mole fraction of 3HV units in the polymer is linear. This result suggests that the split ratio at a branched point of 3-ketovaleryl-CoA in the P(HB-co-HV) synthetic pathway is constant for several fermentation conditions. When the mole fraction of 3HV units has a target value, the feed rate of n-pentanol becomes a function of the feed rate of ethanol and the set value of 3HV, based on the MR model. The mole fraction of 3HV units successfully reached the target value using this strategy. The mole fraction control strategy is combined with an optimal production strategy based on the optimal profile of the specific growth rate. The combined strategy is realized using multivariable controllers and P(3HB-co-3HV) production is maximized with a given value of mole fraction of 3HV units at the final step of fermentation.


Assuntos
Álcoois/análise , Alphaproteobacteria/metabolismo , Microbiologia Industrial/métodos , Poliésteres/metabolismo , Acil Coenzima A/metabolismo , Álcoois/metabolismo , Carbono/metabolismo , Etanol/análise , Etanol/metabolismo , Modelos Biológicos , Nitrogênio/metabolismo , Pentanóis/análise , Pentanóis/metabolismo
7.
J Cardiovasc Surg (Torino) ; 42(1): 139-41, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11292923

RESUMO

Curative resection of a second primary lung cancer in a patient who survived small-cell lung cancer is reported. Small-cell cancer had been treated with chemotherapy followed by surgical resection 12 years before. The patient developed squamous cell cancer as the second primary tumor and underwent lobectomy with mediastinal node dissection. Patients who undergo two curative pulmonary resections of both primary and second primary lung cancer are extremely rare. The patient is alive 176 months after the initial diagnosis of small-cell lung cancer and 28 months after resection for his second primary lung cancer. Careful follow-up at an interval of 3-6 months beyond 10 years is very important because adequate treatments could lead to longer survival of patients with primary small-cell lung cancer.


Assuntos
Carcinoma de Células Pequenas/cirurgia , Neoplasias Pulmonares/cirurgia , Segunda Neoplasia Primária/cirurgia , Carcinoma de Células Pequenas/patologia , Humanos , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Segunda Neoplasia Primária/patologia
8.
J Biosci Bioeng ; 91(4): 390-5, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-16233010

RESUMO

Enterococcus faecium N15 was isolated from nuka (Japanese rice-bran paste), which is utilized as starter in the fermenting of vegetables, and was found to produce a bacteriocin that exhibited a broad spectrum of activity, including activity against Listeria monocytogenes and Bacillus circulans JCM2504. The bacteriocin was sensitive to proteases (alpha-chymotrypsin, proteinase K, trypsin, and pepsin) and alpha-amylase, but it was resistant to lipase. The bacteriocin was resistant to heat treatment at 100 degrees C for 2 h, but its activity was completely lost after autoclaving at 121 degrees C for 15 min. It was active over a wide pH range from 2.0 to 10.0. The bacteriocin showed bactericidal activity against Lactobacillus sake JCM1157 at a concentration of 40 AU/ml. Its molecular weight was estimated by SDS-PAGE to be about 3-5 kDa. PCR primers were designed based on the conserved amino acid sequences of class IIa bacteriocins. A 3-kb DNA fragment was amplified and three open reading frames (ORFs) were found. The first encodes a probable immunity protein of 103 amino acid residues and shows complete homology with the putative immunity protein of E. faecium DPC1146. The second and third ORFs respectively encode a probable transposase gene and an inducing factor. The upstream region of the immunity gene, in which the bacteriocin structural gene is located, was amplified. A homology search revealed that the bacteriocin produced by E. faecium N15 exhibits complete identity to enterocin A, a bacteriocin produced by E. faecium DPC1146. PCR using the primers designed in this study is a rapid and sufficient method of screening for bacteriocin-producing strains.

9.
Appl Microbiol Biotechnol ; 57(5-6): 639-46, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11778872

RESUMO

A mathematical model for kefiran production by Lactobacillus kefiranofaciens was established, in which the effects of pH, substrate and product on cell growth, exopolysaccharide formation and substrate assimilation were considered. The model gave a good representation both of the formation of exopolysaccharides (which are not only attached to cells but also released into the medium) and of the time courses of the production of galactose and glucose in the medium (which are produced and consumed by the cells). Since pH and both lactose and lactic acid concentrations differently affected production and growth activity, the model included the effects of pH and the concentrations of lactose and lactic acid. Based on the mathematical model, an optimal pH profile for the maximum production of kefiran in batch culture was obtained. In this study, a simplified optimization method was developed, in which the optimal pH profile was determined at a particular final fermentation time. This was based on the principle that, at a certain time, switching from the maximum specific growth rate to the critical one (which yields the maximum specific production rate) results in maximum production. Maximum kefiran production was obtained, which was 20% higher than that obtained in the constant-pH control fermentation. A genetic algorithm (GA) was also applied to obtain the optimal pH profile; and it was found that practically the same solution was obtained using the GA.


Assuntos
Lactobacillus/metabolismo , Polissacarídeos Bacterianos/biossíntese , Algoritmos , Biotecnologia , Galactose/metabolismo , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Ácido Láctico/metabolismo , Lactobacillus/crescimento & desenvolvimento , Lactose/metabolismo , Modelos Biológicos
10.
Pathophysiology ; 7(1): 41-45, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10825684

RESUMO

Pleural effusions of seven lung cancer patients (mean age; 58) and seven non-cancer patients (mean age; 49) were examined and Cu(2+) was measured in ceruloplasmin and Fe(3+) in transferrin signals by electron spin resonance (ESR) method. The variations of total Fe and Cu ions, ceruloplasmin and transferrin, proteins, neutrophil cell counts, LDH and nitrite/nitrate were also examined. The Cu(2+) peak was decreased and the Fe(3+) peak was increased in the cancer group. The interrelationship among Cu(2+), total Cu and ceruloplasmin, and among Fe(3+), total Fe and transferrin clarified that Cu(2+) and Fe(3+) are not a representative of ceruloplasmin and transferrin, respectively. The ratio of Cu(2+)/Fe(3+) in pleural effusion distinguished lung cancer from benign inflammation as a cause. The ratio of total Cu/total Fe measured by the chemical analysis method also distinguished these, but the ratio of ceruloplasmin/transferrin was unable to distinguish the cancer. In conclusion, the simple and rapid measurement of Cu(2+)/Fe(3+) by ESR effectively abstracts the variation of total ion concentrations caused by malignant disease.

11.
Am J Physiol Lung Cell Mol Physiol ; 278(4): L719-25, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10749749

RESUMO

The purposes of this study were 1) to identify the nitric oxide (NO) synthase (NOS) isoform responsible for NO-mediated radiation-induced lung injury, 2) to examine the formation of nitrotyrosine, and 3) to see whether nitrotyrosine formation and lung injury are reduced by an inducible NOS (iNOS) inhibitor, aminoguanidine. The left hemithorax of rats was irradiated (20 Gy), and the degree of lung injury, the expression of NOS isoforms, and the formation of nitrotyrosine and superoxide were examined after 2 wk. iNOS mRNA was induced, and endothelial NOS mRNA was markedly increased in the irradiated lung. Nitrotyrosine was detected biochemically and immunohistochemically. Aminoguanidine prevented acute lung injury as indicated by decreased protein concentration and lactate dehydrogenase activity in bronchoalveolar lavage fluid and improved NMR parameters and histology. Furthermore, the formation of nitrotyrosine was significantly reduced in the aminoguanidine group. We conclude that iNOS induction is a major factor in radiation-induced lung injury and that nitrotyrosine formation may participate in the NO-induced pathogenesis.


Assuntos
Pneumopatias/metabolismo , Pulmão/metabolismo , Lesões Experimentais por Radiação/metabolismo , Tirosina/análogos & derivados , Doença Aguda , Animais , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/citologia , Indução Enzimática/fisiologia , L-Lactato Desidrogenase/análise , Pulmão/patologia , Pneumopatias/patologia , Masculino , Nitratos/metabolismo , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo II , Nitritos/metabolismo , Proteínas/análise , Lesões Experimentais por Radiação/patologia , Ratos , Ratos Wistar , Tirosina/biossíntese
12.
J Magn Reson Imaging ; 11(2): 215-22, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10713957

RESUMO

We studied the time course of changes in the Hahn spin-echo decay (Hahn-T2) in lungs of spontaneously breathing living rats at 1 hour, 3 hours, and 7 days following oleic acid injection. Motion artifacts were minimized by using the motion-insensitive interleaved rapid line scan (ILS) imaging technique. Prior to injury, the lungs exhibited two resolvable exponential Hahn-T2 components. One and 3 hours after injury the decay showed a regionally nonuniform behavior, which was fit with one, two, or three exponential components. The short and medium components increased at 1 and 3 hours after injection. The third, much longer, component is probably due to intraalveolar pulmonary edema. After 7 days the Hahn decay was similar to that observed before injury, probably reflecting resolution of the edema. Our data suggest that Hahn-T2 measurements can be used to characterize the time course and regional distribution of lung injury in living animals.


Assuntos
Pulmão/patologia , Imageamento por Ressonância Magnética , Ácido Oleico , Edema Pulmonar/induzido quimicamente , Animais , Artefatos , Feminino , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética , Edema Pulmonar/patologia , Ratos , Ratos Sprague-Dawley , Fatores de Tempo
13.
J Biosci Bioeng ; 90(4): 363-7, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-16232873

RESUMO

Yellow pigment production in exponential fed-batch cultivation of Monascus sp. was studied. Due to the difficulty of measuring the optical density for accurate determination of the cell concentration, a capacitance probe was employed on-line. The feed rate needed to keep the specific growth rate, mu, constant in fed-batch culture was determined on the basis of the cell concentration measured by the capacitance probe. Control of mu was improved by using updated information on the cell concentration compared with the simple feed-forward determination method using the initial cell concentration only. The highest specific pigment production rate was achieved with a mu of 0.02 h(-1) in the feeding phase. However, among several fermentation examined, the largest pigment production in the final step was obtained at a mu of 0.01 h(-1); in each case the same amount of substrates was used. An investigation of the optimal initial glucose concentration revealed that pigment production was maximum when the initial glucose concentration in the batch mode was 10 g/l and mu was 0.01 h(-1) in the fed-batch mode. It was also found that the pellet weight in the fermentation could be accurately estimated by image analysis. The ratio of the mycelium weight to the total cell weight estimated from information on the total cell weight and the estimated pellet weight was found to be more than 80%. However, no clear quantitative relationship could be discerned between the specific pigment production rate, rho, and the ratio of mycelium in the cell population.

14.
J Biotechnol ; 71(1-3): 133-41, 1999 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-10483103

RESUMO

A simple mathematical model describing the cell cycle dependency of rice alpha-amylase production by a recombinant yeast was constructed to investigate the efficiency of cell cycle population control. First, the effects of the glucose concentration and cultivation temperature on the specific growth rate, the specific production rate of rice alpha-amylase, and the distribution of the cell cycle population were studied under balanced growth conditions. On the basis of the results, parameter values for the mathematical model were then estimated. The proposed model was shown to be applicable for unbalanced as well as balanced growth phases. The optimal control strategy in respect of temperature and glucose concentration for maximum rice alpha-amylase production, taking into account the cell cycle population, was determined and the result was compared with that obtained by a simple mathematical model in which cell cycle distribution was not considered. Finally, the effect of the initial population of each cell cycle phase on the final amount of the product under optimal operational conditions was investigated. The simulation and experimental data coincided well with each other, and the model was used to optimize the control strategy for maximum alpha-amylase production.


Assuntos
Proteínas Recombinantes/biossíntese , Saccharomyces cerevisiae/metabolismo , alfa-Amilases/biossíntese , Ciclo Celular , Saccharomyces cerevisiae/crescimento & desenvolvimento
15.
Appl Environ Microbiol ; 65(7): 3134-41, 1999 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10388714

RESUMO

To control the pH during antimicrobial peptide (nisin) production by a lactic acid bacterium, Lactococcus lactis subsp. lactis (ATCC11454), a novel method involving neither addition of alkali nor a separation system such as a ceramic membrane filter and electrodialyzer was developed. A mixed culture of L. lactis and Kluyveromyces marxianus, which was isolated from kefir grains, was utilized in the developed system. The interaction between lactate production by L. lactis and its assimilation by K. marxianus was used to control the pH. To utilize the interaction of these microorganisms to maintain high-level production of nisin, the kinetics of growth of, and production of lactate, acetate, and nisin by, L. lactis were investigated. The kinetics of growth of and lactic acid consumption by K. marxianus were also investigated. Because the pH of the medium could be controlled by the lactate consumption of K. marxianus and the specific lactate consumption rate of K. marxianus could be controlled by changing the dissolved oxygen (DO) concentration, a cascade pH controller coupled with DO control was developed. As a result, the pH was kept constant because the lactate level was kept low and nisin accumulated in the medium to a high level compared with that attained using other pH control strategies, such as with processes lacking pH control and those in which pH is controlled by addition of alkali.


Assuntos
Kluyveromyces/metabolismo , Lactococcus lactis/metabolismo , Nisina/biossíntese , Aerobiose , Anaerobiose , Meios de Cultura , Grão Comestível/microbiologia , Concentração de Íons de Hidrogênio , Kluyveromyces/crescimento & desenvolvimento , Ácido Láctico/metabolismo , Lactococcus lactis/crescimento & desenvolvimento
16.
J Anim Sci ; 77(3): 756-61, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10229374

RESUMO

Feeding-deterrent chemicals were extracted from cattle feces and then separated with three chromatographic methods. Behavioral two-choice test bioassays with cattle were used to examine the deterrent properties of the fractions. Cattle feces were extracted with diethyl ether, and the extracts were separated into neutral, acidic, and basic fractions. Of the three fractions, only the neutral fraction was a deterrent. Separation of the ether-soluble neutral chemicals was conducted with an open column of silica gel using four carrier solutions consisting of pentane and ether. Fraction B (eluted with the carrier solution; pentane:ether = 90:10) was the most effective deterrent among the four fractions. This fraction was divided into 10 fractions by liquid chromatography. Fractions 6, 7, and 8 seemed to deter cattle from feeding. The combined Fractions 6, 7, and 8 were separated into 15 fractions with HPLC. Deterrent activities were detected in Fractions 2, 3, 9, 10, 11, 12, 13, and 14, suggesting that deterrents were separated into two groups using HPLC. These results suggested that several specific chemicals in feces are involved in inhibiting cattle from ingesting grass near cattle feces.


Assuntos
Bovinos/fisiologia , Fezes/química , Comportamento Alimentar , Animais , Bioensaio , Cromatografia Líquida de Alta Pressão/veterinária , Cromatografia Líquida/veterinária , Preferências Alimentares
17.
Biotechnol Bioeng ; 62(5): 518-25, 1999 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-10099560

RESUMO

A novel strategy for the maximum production of a biodegradable copolymer, poly(3-hydroxybutyric-co-hydroxyvaleric) acid, P(HB-co-HV), was developed, based on the kinetic parameters obtained from fed-batch culture experiments of Alcaligenes eutrophus. The effects of various culture conditions such as mole ratio of carbon:nitrogen in feed medium (C/N); total fatty acids concentrations; and addition ratio of fatty acids on cultivation properties such as the specific rates of cell formation, mu (h-1), P(HB-co-HV) production, rho[g.P(HB-co-HV)/g.cell/h], production yield from fatty acids [g.P(HB-co-HV)/g.fatty acid], and mole fraction of monomeric units in the copolymer [mol.(HV)/{mol.(HB) + mol.(HV)}], were investigated. When nitrogen supply was sufficient for cell growth; that is, C/N (mol.nitrogen atom/mol.carbon atom) was low, mu was high, but rho and the production yield were low, because fatty acids were used mainly for energy formation and anabolic reactions in the cells. On the other hand, when nitrogen supply was limited for cell growth-that is, C/N was high-rho was high. The highest value of rho was obtained when C/N was 75. As the mole ratio of valeric acid (VA) to butyric acid (BA) in the feed medium was increased, the mole fraction of HV units in P(HB-co-HV) increased linearly. When the ratio of BA to VA in the feed medium was kept at a constant value, but C/N was increased, the mole fraction of HV units decreased. In particular, when C/N was >12, the mole fraction of HV units decreased linearly as C/N increased. When VA was utilized as the sole carbon source and C/N was fixed at 4, P(HB-co-HV) with the highest mole fraction of HV units (67 mol%) was achieved. From these results, it was shown that both C/N and the mole ratio of BA to VA in the feed medium should be well controlled for an optimal production of P(HB-co-HV) with the desired value of the mole fraction of HV units. When the addition ratio of butyric acid was 50 wt% of total fatty acids, a maximum production strategy for P(HB-co-HV) was developed and realized experimentally, which was based on a model of the relationship between mu and rho.


Assuntos
Alcaligenes/metabolismo , Poliésteres/metabolismo , Alcaligenes/crescimento & desenvolvimento , Biodegradação Ambiental , Biotecnologia , Ácidos Graxos/metabolismo , Fermentação , Cinética
18.
Appl Microbiol Biotechnol ; 51(2): 164-9, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10091321

RESUMO

To maximize the productivity of virginiamycin, which is a commercially important antibiotic as an animal feed additive, an empirical approach was employed in the batch culture of Streptomyces virginiae. Here, the effects of dissolved oxygen (DO) concentration and agitation speed on the maximum cell concentration at the production phase, as well as on the productivity of virginiamycin, were investigated. To maintain the DO concentration in the fermentor at a certain level, either the agitation speed or the inlet oxygen concentration of the supply gas was manipulated. It was found that increasing the agitation speed had a positive effect on the antibiotic productivity independent of the DO concentration. The optimum DO concentration, agitation speed and addition of an autoregulator, virginiae butanolide C (VB-C), were determined to maximize virginiamycin productivity. The optimal strategy was to start the cultivation at 450 rpm and to continue until the DO concentration reached 80%. After reaching 80%, the DO concentration was maintained at this level by changing the agitation speed, up to a maximum of 800 rpm. The addition of an optimal amount of the autoregulator VB-C in an experiment resulted in the maximal production of virginiamycin M (399 mg/l), which was about 1.8-fold those obtained previously.


Assuntos
Antibacterianos/biossíntese , Streptomyces/crescimento & desenvolvimento , Streptomyces/metabolismo , Virginiamicina/biossíntese , 4-Butirolactona/análogos & derivados , 4-Butirolactona/farmacologia , Técnicas Bacteriológicas , Meios de Cultura , Fermentação , Oxigênio/farmacologia , Streptomyces/efeitos dos fármacos
19.
Am J Physiol ; 276(1): L207-12, 1999 01.
Artigo em Inglês | MEDLINE | ID: mdl-9887073

RESUMO

The free water content of lung tissue was investigated by dielectric spectroscopy in normal lungs and in pulmonary edema induced by oleic acid in rats. The dielectric relaxation in a frequency range of 10(7) to 10(10) Hz was measured with the time domain reflectometry method at 25 degreesC. Three dielectric relaxation processes were analyzed for the lung tissue. A high-frequency process around 10 GHz was attributed to the orientation of free water molecules based on the relaxation time [log tauh (in s) = -11.03]. The dielectric strength (Delta epsilon) of this high-frequency peak (Delta epsilonh) should reflect the amount of free water in the tissue. Because the measured Delta epsilonh depended on the air content of the lung samples, the value of Delta epsilonh was corrected for the air content of each sample as determined by the point-counting method in the area where the time domain reflectometry data were obtained. The lungs of rats that received an injection of oleic acid had a significantly increased free water content [(Delta epsilonh of lung/Delta epsilon of pure water) x density of pure water] compared with that in the normal lung (0.76 vs. 0.59 g/cm3). These results indicate that free water occupies approximately 60% of the total volume of normal lung tissue and that there is an increase in free water in pulmonary edema.


Assuntos
Água Corporal/metabolismo , Pulmão/metabolismo , Edema Pulmonar/metabolismo , Animais , Pulmão/patologia , Masculino , Modelos Biológicos , Edema Pulmonar/patologia , Ratos , Ratos Wistar , Valores de Referência
20.
Metab Eng ; 1(4): 299-308, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10937823

RESUMO

The aim of this study is to develop a strategy for maximum production of a target product with a simplified model derived from a metabolic reaction network through an example of lysine production. Based on the model, a search for the optimal specific growth rate profile was conducted among the available conditions of batch fermentation based on the derived model, when the total fermentation time was fixed. The optimal specific growth rate was obtained as a boundary control: initially, the specific growth rate was maintained at a maximum value and was subsequently switched to a critical value giving the maximum specific production rate. To make the specific growth rate follow this optimal profile as accurately as possible in batch mode, first, an appropriate initial concentration of leucine was employed in the experiment. Second, the feeding strategy of leucine was further studied. The specific growth rate profile with feeding was closer to the optimal one and the amount of lysine produced at the final stage of fermentation was increased about twofold, compared to that in the batch fermentation. Finally, the strategy was summarized as an algorithm for general use of this method.


Assuntos
Lisina/biossíntese , Modelos Biológicos , Reatores Biológicos , Biotecnologia , Corynebacterium/crescimento & desenvolvimento , Corynebacterium/metabolismo , Fermentação , Glucose/metabolismo , Leucina/metabolismo
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