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1.
J Agric Food Chem ; 71(24): 9451-9459, 2023 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-37279371

RESUMO

3-Hydroxytyrosol (HT) is a super antioxidant possessing many physiological advantages for human health. However, the extraction of natural HT from olive (Olea europaea) is expensive, and its chemical synthesis presents an environmental burden. Therefore, microbial production of HT from renewable sources has been investigated over the past decade. In the present study, we modified the chromosome of a phenylalanine-producing strain of Escherichia coli to generate an HT-producing strain. The initial strain showed good HT production in tests performed by test tube cultivation, but this performance did not transfer to jar-fermenter cultivation. To grow well and achieve higher titers, the chromosome was further engineered and the cultivation conditions were further modified. The final strain achieved a higher HT titer (8.8 g/L) and yield (8.7%) from glucose in the defined synthetic medium. These yields are the best reported to date for the biosynthesis of HT from glucose.


Assuntos
Proteínas de Escherichia coli , Escherichia coli , Humanos , Escherichia coli/genética , Escherichia coli/metabolismo , Glucose , Reatores Biológicos , Proteínas de Escherichia coli/metabolismo , Fermentação , Engenharia Metabólica
2.
Sci Rep ; 13(1): 260, 2023 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-36609443

RESUMO

Public displays, such as liquid crystal displays (LCDs), are often used in urban green spaces. However, these display devices often tarnish the green landscape of urban green spaces due to their artificial materials. We previously proposed a green landscape-friendly grass animation display that dynamically controls the grass color pixel by pixel. The grass color is changed by moving a green grass length in yellow grass, and the grass animation display runs simple animations using grayscale images. In our previous study, the color scale is subjectively mapped to the green grass length. However, this method fails to display the grass colors corresponding to the color scale based on objective evaluations. Herein, we introduce a dynamic grass color scale display technique based on the grass length. We develop a grass color scale setting procedure to map the grass length to the five-level color scale through image processing. In the outdoor experiment of the grass color scale setting procedure, the color scale corresponds to the green grass length based on a viewpoint. Finally, we demonstrate a grass animation display to show the animations with the color scale using experimental results.


Assuntos
Cristais Líquidos , Poaceae , Cor , Processamento de Imagem Assistida por Computador/métodos
3.
Sensors (Basel) ; 20(22)2020 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33228069

RESUMO

We are developing a social mobile robot that has a name calling function using a face memorization system. It is said that it is an important function for a social robot to call to a person by her/his name, and the name calling can make a friendly impression of the robot on her/him. Our face memorization system has the following features: (1) When the robot detects a stranger, it stores her/his face images and name after getting her/his permission. (2) The robot can call to a person whose face it has memorized by her/his name. (3) The robot system has a sleep-wake function, and a face classifier is re-trained in a REM sleep state, or execution frequencies of information processes are reduced when it has nothing to do, for example, when there is no person around the robot. In this paper, we confirmed the performance of these functions and conducted an experiment to evaluate the impression of the name calling function with research participants. The experimental results revealed the validity and effectiveness of the proposed face memorization system.

4.
Radiat Prot Dosimetry ; 179(1): 18-25, 2018 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-29036482

RESUMO

Absorbed dose rates in air from natural radionuclides were measured by a car-borne survey in southern Vietnam. The mean absorbed dose rate in air for southern Vietnam, which consists of the south-east region and the Mekong River Delta region, was 64 ± 18 nGy h-1, while rates for the two regions were 61 ± 17 and 66 ± 19 nGy h-1, respectively. These dose rates were respectively 1.2, 2.1 and 0.9 times the measured values that were calculated on the basis of activity concentrations of soil samples in a previous study. It was considered that measured dose rate in the south-east region was influenced by the presence of artificial structures such as high-rise buildings and roads. The effective dose due to terrestrial gamma radiation for southern Vietnam was calculated to be 0.55 mSv y-1 which is 1.2 times higher than the world-wide average of 0.48 mSv y-1.


Assuntos
Radiação de Fundo , Exposição Ambiental/análise , Raios gama , Radioisótopos/análise , Automóveis , Doses de Radiação , Monitoramento de Radiação/métodos , Vietnã
5.
PLoS One ; 12(1): e0171100, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28129382

RESUMO

A car-borne survey was carried out in the northwestern, or Tokatsu, area of Chiba Prefecture, Japan, to make a detailed distribution map of absorbed dose rate in air four years after the Fukushima Daiichi Nuclear Power Plant accident. This area was chosen because it was the most heavily radionuclide contaminated part of Chiba Prefecture and it neighbors metropolitan Tokyo. Measurements were performed using a 3-in × 3-in NaI(Tl) scintillation spectrometer in June 2015. The survey route covered the whole Tokatsu area which includes six cities. A heterogeneous distribution of absorbed dose rate in air was observed on the dose distribution map. Especially, higher absorbed dose rates in air exceeding 80 nGy h-1 were observed along national roads constructed using high porosity asphalt, whereas lower absorbed dose rates in air were observed along local roads constructed using low porosity asphalt. The difference between these asphalt types resulted in a heterogeneous dose distribution in the Tokatsu area. The mean of the contribution ratio of artificial radionuclides to absorbed dose rate in air measured 4 years after the accident was 29% (9-50%) in the Tokatsu area. The maximum absorbed dose rate in air, 201 nGy h-1 was observed at Kashiwa City. Radiocesium was deposited in the upper 1 cm surface layer of the high porosity asphalt which was collected in Kashiwa City and the environmental half-life of the absorbed dose rate in air was estimated to be 1.7 years.


Assuntos
Poluentes Radioativos do Ar , Acidente Nuclear de Fukushima , Monitoramento de Radiação , Cinza Radioativa , Radioisótopos de Césio/toxicidade , Humanos , Doses de Radiação , Radiometria , Inquéritos e Questionários , Tóquio
6.
J Exp Med ; 213(13): 3057-3073, 2016 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-27815325

RESUMO

CD8+ tissue-resident memory T cells (TRM cells) reside permanently in nonlymphoid tissues and provide a first line of protection against invading pathogens. However, the precise localization of CD8+ TRM cells in the lung, which physiologically consists of a markedly scant interstitium compared with other mucosa, remains unclear. In this study, we show that lung CD8+ TRM cells localize predominantly in specific niches created at the site of regeneration after tissue injury, whereas peripheral tissue-circulating CD8+ effector memory T cells (TEM cells) are widely but sparsely distributed in unaffected areas. Although CD69 inhibited sphingosine 1-phosphate receptor 1-mediated egress of CD8+ T cells immediately after their recruitment into lung tissues, such inhibition was not required for the retention of cells in the TRM niches. Furthermore, despite rigid segregation of TEM cells from the TRM niche, prime-pull strategy with cognate antigen enabled the conversion from TEM cells to TRM cells by creating de novo TRM niches. Such damage site-specific localization of CD8+ TRM cells may be important for efficient protection against secondary infections by respiratory pathogens.


Assuntos
Antígenos CD/imunologia , Antígenos de Diferenciação de Linfócitos T/imunologia , Linfócitos T CD8-Positivos/imunologia , Memória Imunológica , Vírus da Influenza A/imunologia , Lectinas Tipo C/imunologia , Pulmão/imunologia , Infecções por Orthomyxoviridae/imunologia , Animais , Antígenos CD/genética , Antígenos de Diferenciação de Linfócitos T/genética , Linfócitos T CD8-Positivos/patologia , Lectinas Tipo C/genética , Pulmão/patologia , Camundongos , Camundongos Transgênicos , Infecções por Orthomyxoviridae/genética , Infecções por Orthomyxoviridae/patologia
7.
J Virol ; 89(2): 1468-73, 2015 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-25378499

RESUMO

Toll-like receptor 7 and Myd88 are required for antiretroviral antibody and germinal center responses, but whether somatic hypermutation and class-switch recombination are required for antiretroviral immunity has not been examined. Mice deficient in activation-induced cytidine deaminase (AID) resisted Friend virus infection, produced virus-neutralizing antibodies, and controlled viremia. Passive transfer demonstrated that immune IgM from AID-deficient mice contributes to Friend virus control in the presence of virus-specific CD4+ T cells.


Assuntos
Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Vírus da Leucemia Murina de Friend/imunologia , Leucemia Experimental/imunologia , Infecções por Retroviridae/imunologia , Hipermutação Somática de Imunoglobulina , Infecções Tumorais por Vírus/imunologia , Animais , Linfócitos T CD4-Positivos/imunologia , Citidina Desaminase/deficiência , Imunização Passiva , Switching de Imunoglobulina , Imunoglobulina M/imunologia , Leucemia Experimental/virologia , Camundongos , Infecções por Retroviridae/virologia , Infecções Tumorais por Vírus/virologia
8.
PLoS Pathog ; 10(3): e1003937, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24651250

RESUMO

In chronic viral infections, persistent antigen presentation causes progressive exhaustion of virus-specific CD8+ T cells. It has become clear, however, that virus-specific naïve CD8+ T cells newly generated from the thymus can be primed with persisting antigens. In the setting of low antigen density and resolved inflammation, newly primed CD8+ T cells are preferentially recruited into the functional memory pool. Thus, continual recruitment of naïve CD8+ T cells from the thymus is important for preserving the population of functional memory CD8+ T cells in chronically infected animals. Friend virus (FV) is the pathogenic murine retrovirus that establishes chronic infection in adult mice, which is bolstered by the profound exhaustion of virus-specific CD8+ T cells induced during the early phase of infection. Here we show an additional evasion strategy in which FV disseminates efficiently into the thymus, ultimately leading to clonal deletion of thymocytes that are reactive to FV antigens. Owing to the resultant lack of virus-specific recent thymic emigrants, along with the above exhaustion of antigen-experienced peripheral CD8+ T cells, mice chronically infected with FV fail to establish a functional virus-specific CD8+ T cell pool, and are highly susceptible to challenge with tumor cells expressing FV-encoded antigen. However, FV-specific naïve CD8+ T cells generated in uninfected mice can be primed and differentiate into functional memory CD8+ T cells upon their transfer into chronically infected animals. These findings indicate that virus-induced central tolerance that develops during the chronic phase of infection accelerates the accumulation of dysfunctional memory CD8+ T cells.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Tolerância Imunológica/imunologia , Memória Imunológica/imunologia , Infecções por Retroviridae/imunologia , Timo/virologia , Envelhecimento , Animais , Linfócitos T CD8-Positivos/citologia , Diferenciação Celular/imunologia , Doença Crônica , Feminino , Citometria de Fluxo , Vírus da Leucemia Murina de Friend/imunologia , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Transgênicos , Timo/imunologia
9.
Int J Urol ; 21(1): 81-5, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23659522

RESUMO

OBJECTIVES: To evaluate the clinical efficacy of transurethral resection of the prostate on nocturia and sleep disorders in patients with lower urinary tract symptoms suggestive of benign prostatic obstruction. METHODS: A prospective multicenter study including lower urinary tract symptoms suggestive of benign prostatic obstruction patients with nocturia (twice or more) undergoing transurethral resection of the prostate was carried out. All patients were assessed using the International Prostate Symptom Score and the Pittsburgh Sleep Quality Index at baseline, and 6 months after transurethral resection of the prostate. RESULTS: Overall, 49 patients were included in the study. A total of 20 of them (41%) had a sleep disorder defined as a score of 5.5 or more on the Pittsburgh Sleep Quality Index global score. The nocturia score significantly correlated with component 4 of the Pittsburgh Sleep Quality Index (habitual sleep efficiency). Nocturia significantly decreased after transurethral resection of the prostate from 3.0 ± 1.2 to 1.9 ± 0.8, whereas the global Pittsburgh Sleep Quality Index score did not. In 20 patients with a sleep disorder before transurethral resection of the prostate, subjective sleep quality (component 1) and habitual sleep efficiency (component 4) significantly decreased after transurethral resection of the prostate, but this was not the case for the global Pittsburgh Sleep Quality Index score. In 16 patients with a persistent sleep disorder after transurethral resection of the prostate, International Prostate Symptom Score, voiding and storage symptoms score were higher than those of patients without a sleep disorder, although the nocturia score improved equivalently in both groups. CONCLUSIONS: Transurethral resection of the prostate diminishes nocturnal urinary frequency and partly improves sleep quality in patients with nocturia and lower urinary tract symptoms suggestive of benign prostatic obstruction. A persistent sleep disorder after transurethral resection of the prostate is associated with persistent voiding and storage symptoms.


Assuntos
Sintomas do Trato Urinário Inferior/complicações , Noctúria/etiologia , Hiperplasia Prostática/complicações , Hiperplasia Prostática/cirurgia , Transtornos do Sono-Vigília/etiologia , Ressecção Transuretral da Próstata , Idoso , Idoso de 80 Anos ou mais , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
10.
Urol Int ; 89(2): 215-21, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22832092

RESUMO

OBJECTIVE: To evaluate the efficacy of imidafenacin on nocturia and sleep disorder in patients with overactive bladder (OAB). PATIENTS AND METHODS: A prospective multicenter study of imidafenacin 0.1 mg twice daily for patients with OAB and nocturia was conducted. At baseline and at week 4 and 8, patients were assessed using the overactive bladder symptom score (OABSS), frequency volume charts (FVC) and the Pittsburgh Sleep Quality Index (PSQI). RESULTS: Treatment with imidafenacin significantly improved OAB symptoms. Imidafenacin also improved PSQI, especially subjective sleep quality, sleep latency and daytime dysfunction. In FVC, the number of daytime voids and nighttime voids significantly decreased and average voided volume significantly increased after imidafenacin. Subanalysis of FVC based on the patients' age revealed that nocturnal polyuria was more often found in patients aged 75 years or over than in those aged under 75 years (79 vs. 55%, p < 0.05). Treatment with imidafenacin significantly reduced the nocturnal polyuria index only in patients aged 75 years or over. CONCLUSIONS: Imidafenacin can improve nocturia and sleep disorder in patients with OAB. The efficacy of imidafenacin on nocturia is attributable to an increase in bladder capacity and a decrease in nocturnal urine volume. We conclude that imidafenacin is an effective and safe drug for nocturia in patients with OAB.


Assuntos
Imidazóis/farmacologia , Noctúria/tratamento farmacológico , Transtornos do Sono-Vigília/tratamento farmacológico , Bexiga Urinária Hiperativa/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Antagonistas Muscarínicos/farmacologia , Poliúria/tratamento farmacológico , Sono/efeitos dos fármacos , Fatores de Tempo , Urodinâmica/efeitos dos fármacos
11.
Hinyokika Kiyo ; 57(6): 297-302, 2011 Jun.
Artigo em Japonês | MEDLINE | ID: mdl-21795831

RESUMO

We investigated the optimum initial dose and timing of administration of α1A-adrenoceptor antagonist silodosin for treatment of lower urinary tract symptoms associated with benign prostatic hyperplasia (BPH/LUTS). Ninety-eight patients were given a 4 mg dose after breakfast (group A), 4 mg after supper (group B), or 4 mg after breakfast and after supper (group C). At baseline, 4, 8 and 12 weeks after treatment, we assessed International Prostate Symptom Score (IPSS) and quality of life (QOL) index. Twenty-five percent or less improvement of total IPSS and no improvement of QOL index compared with baseline were defined as treatment failure at each evaluation point. Otherwise treatment was considered effective. In group A and group B, patients with treatment failure at 4 or 8 weeks after treatment, the dose of silodosin was increased to 8 mg daily. At the end of the study, 83 patients were evaluable. At 12 weeks after treatment, 20 of the 31 patients in group A and 22 of the 29 patients in group B remained on the 4 mg dose ; silodosin was effective in 65 and 76% of the patients, respectively. When patients with dose escalation were included, silodosin was effective in 81 and 90% of the patients, respectively. Silodosin was effective in 18 of the 23(78%) patients in group C, although improvement of total IPSS and voiding symptom score of IPSS at 12 weeks after treatment was better in group C than in group A or group B, the difference was not significant. In patients with IPSS less than 20, the degree of improvement of IPSS was similar among the 3 groups. In contrast, in patients with IPSS of 20 or greater the degree of improvement was better in group C than in group B or group C, but the difference was not significant. Storage symptom score of IPSS was significantly improved in all 3 groups without any significant difference among the 3 groups. Three patients (52, 59 and 76 years old) experienced abnormal ejaculation. In conclusion, 4 mg of silodosin daily showed effectiveness against BPH/LUTS, but 8 mg of silodosin daily might be better for patients with severe LUTS.


Assuntos
Antagonistas de Receptores Adrenérgicos alfa 1/administração & dosagem , Indóis/administração & dosagem , Hiperplasia Prostática/complicações , Prostatismo/tratamento farmacológico , Idoso , Humanos , Masculino , Qualidade de Vida , Resultado do Tratamento
12.
J Biol Chem ; 285(42): 32105-15, 2010 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-20716528

RESUMO

A lysine residue in the putative proton uptake pathway of the ATP synthase a-subunit is found only in alkaliphilic Bacillus species and is proposed to play roles in proton capture, retention and passage to the synthase rotor. Here, Lys-180 was replaced with alanine (Ala), glycine (Gly), cysteine (Cys), arginine (Arg), or histidine (His) in the chromosome of alkaliphilic Bacillus pseudofirmus OF4. All mutants exhibited octylglucoside-stimulated ATPase activity and ß-subunit levels at least as high as wild-type. Purified mutant F(1)F(0)-ATP synthases all contained substantial a-subunit levels. The mutants exhibited diverse patterns of native (no octylglucoside) ATPase activity and a range of defects in malate growth and in vitro ATP synthesis at pH 10.5. ATP synthesis by the Ala, Gly, and His mutants was also impaired at pH 7.5 in the presence of a protonophoric uncoupler. Thus Lys-180 plays a role when the protonmotive force is reduced at near neutral, not just at high pH. The Arg mutant exhibited no ATP synthesis activity in the alkaliphile setting although activity was reported for a K180R mutant of a thermoalkaliphile synthase (McMillan, D. G., Keis, S., Dimroth, P., and Cook, G. M. (2007) J. Biol. Chem. 282, 17395-17404). The hypothesis that a-subunits from extreme alkaliphiles and the thermoalkaliphile represent distinct variants was supported by demonstration of the importance of additional alkaliphile-specific a-subunit residues, not found in the thermoalkaliphile, for malate growth of B. pseudofirmus OF4. Finally, a mutant B. pseudofirmus OF4 synthase with switched positions of Lys-180 (helix 4) and Gly-212 (helix 5) retained significant coupled synthase activity accompanied by proton leakiness.


Assuntos
Complexos de ATP Sintetase , Bacillus/fisiologia , Proteínas de Bactérias , Isoenzimas , Lisina/genética , Fosforilação Oxidativa , Subunidades Proteicas , Complexos de ATP Sintetase/química , Complexos de ATP Sintetase/genética , Complexos de ATP Sintetase/metabolismo , Adenosina Trifosfatases/química , Adenosina Trifosfatases/genética , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Concentração de Íons de Hidrogênio , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Lisina/metabolismo , Dados de Sequência Molecular , Mutação , Conformação Proteica , Subunidades Proteicas/química , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Alinhamento de Sequência
13.
Environ Technol ; 31(8-9): 845-56, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20662376

RESUMO

Alkaliphiles are microorganisms that can grow in alkaline environments, i.e. pH >9.0. Their enzymes, especially extracellular enzymes, are able to function in their catalytic activities under high alkaline pH values because of their stability under these conditions. Proteases, protein degrading enzymes, are one of the most produced enzymes in industry. Among proteases, alkaline proteases, which are added to some detergents, are the most produced. Other alkaline enzymes, e.g. alkaline cellulases, alkaline amylases, and alkaline lipases, are also adjuncts to detergents for improving cleaning efficiency. Alkaline enzymes often show activities in a broad pH range, thermostability, and tolerance to oxidants compared to neutral enzymes. Alkaliphilic Bacillus species are the most characterized organisms among alkaliphiles. They produce so many extracellular alkaline-adapted enzymes that they are often good sources for industrial enzymes. As a patent strain, the whole genome sequence of alkaliphilic Bacillus halodurans C-125 has been sequenced for the first time. In addition, an increasing number of whole genomic sequences and structural analyses of proteins in alkaliphiles, development of genetic engineering techniques and physiological analyses will reveal the alkaline adaptation mechanisms of alkaliphilic Bacillus species and the structural basis of their enzymatic functions. This information opens up the possibility of new applications. In this paper we describe, first, the physiologies of environmental adaptations, and then the applications of enzymes and microorganisms themselves in alkaliphilic Bacillus species.


Assuntos
Bacillus/metabolismo , Microbiologia Industrial/métodos , Amilases , Bacillus/enzimologia , Ciclodextrinas , Endo-1,4-beta-Xilanases , Serina Endopeptidases
14.
Biochim Biophys Acta ; 1797(8): 1362-77, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20193659

RESUMO

This review focuses on the ATP synthases of alkaliphilic bacteria and, in particular, those that successfully overcome the bioenergetic challenges of achieving robust H+-coupled ATP synthesis at external pH values>10. At such pH values the protonmotive force, which is posited to provide the energetic driving force for ATP synthesis, is too low to account for the ATP synthesis observed. The protonmotive force is lowered at a very high pH by the need to maintain a cytoplasmic pH well below the pH outside, which results in an energetically adverse pH gradient. Several anticipated solutions to this bioenergetic conundrum have been ruled out. Although the transmembrane sodium motive force is high under alkaline conditions, respiratory alkaliphilic bacteria do not use Na+- instead of H+-coupled ATP synthases. Nor do they offset the adverse pH gradient with a compensatory increase in the transmembrane electrical potential component of the protonmotive force. Moreover, studies of ATP synthase rotors indicate that alkaliphiles cannot fully resolve the energetic problem by using an ATP synthase with a large number of c-subunits in the synthase rotor ring. Increased attention now focuses on delocalized gradients near the membrane surface and H+ transfers to ATP synthases via membrane-associated microcircuits between the H+ pumping complexes and synthases. Microcircuits likely depend upon proximity of pumps and synthases, specific membrane properties and specific adaptations of the participating enzyme complexes. ATP synthesis in alkaliphiles depends upon alkaliphile-specific adaptations of the ATP synthase and there is also evidence for alkaliphile-specific adaptations of respiratory chain components.


Assuntos
Bactérias/enzimologia , ATPases Translocadoras de Prótons/fisiologia , Adaptação Fisiológica , Trifosfato de Adenosina/biossíntese , Sequência de Aminoácidos , Bacillus/enzimologia , Metabolismo Energético , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Fosforilação , ATPases Translocadoras de Prótons/química
15.
Adv Microb Physiol ; 55: 1-79, 317, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19573695

RESUMO

Of all the molecular determinants for growth, the hydronium and hydroxide ions are found naturally in the widest concentration range, from acid mine drainage below pH 0 to soda lakes above pH 13. Most bacteria and archaea have mechanisms that maintain their internal, cytoplasmic pH within a narrower range than the pH outside the cell, termed "pH homeostasis." Some mechanisms of pH homeostasis are specific to particular species or groups of microorganisms while some common principles apply across the pH spectrum. The measurement of internal pH of microbes presents challenges, which are addressed by a range of techniques under varying growth conditions. This review compares and contrasts cytoplasmic pH homeostasis in acidophilic, neutralophilic, and alkaliphilic bacteria and archaea under conditions of growth, non-growth survival, and biofilms. We present diverse mechanisms of pH homeostasis including cell buffering, adaptations of membrane structure, active ion transport, and metabolic consumption of acids and bases.


Assuntos
Archaea/fisiologia , Fenômenos Fisiológicos Bacterianos , Citoplasma/química , Homeostase , Concentração de Íons de Hidrogênio
16.
Arch Microbiol ; 191(8): 649-57, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19543710

RESUMO

YfkE, a protein from Bacillus subtilis, exhibits homology to the Ca(2+):Cation Antiporter (CaCA) Family. In a fluorescence-based assay of everted membrane vesicles prepared from Na(+)(Ca(2+))/H(+) antiporter-defective mutant Escherichia coli KNabc, YfkE exhibited robust Ca(2+)/H(+) antiport activity, with a K (m) for Ca(2+) estimated at 12.5 muM at pH 8.5 and 113 muM at pH 7.5. Neither Na(+) nor K(+) served as a substrate. Mg(2+) also did not serve as a substrate, but inhibited the Ca(2+)/H(+) antiporter activity. The Ca(2+) transport capability of YfkE was also observed directly by transport assays in everted membrane vesicles using radiolabeled (45)Ca(2+). Transcriptional analysis from the putative yfkED operon using beta-garactosidase activity as a reporter revealed that both of the yfkE and yfkD genes are regulated by forespore-specific sigma factor, SigG, and the general stress response regulator, SigB. These results suggest that YfkE may be needed for Ca(2+) signaling in the sporulation or germination process in B. subtilis. ChaA is proposed as the designation for YfkE of B. subtilis.


Assuntos
Antiporters/metabolismo , Bacillus subtilis/genética , Proteínas de Bactérias/metabolismo , Proteínas de Transporte de Cátions/metabolismo , Antiporters/genética , Bacillus subtilis/metabolismo , Proteínas de Bactérias/genética , Sinalização do Cálcio , Proteínas de Transporte de Cátions/genética , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Óperon , Fator sigma/metabolismo , Especificidade por Substrato
17.
J Biol Chem ; 284(13): 8714-25, 2009 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-19176524

RESUMO

The membrane-embedded rotor in the F(0) sector of proton-translocating ATP synthases is formed from hairpin-like c-subunits that are protonated and deprotonated during energization of ATP synthesis. This study focuses on two c-subunit motifs that are unique to synthases of extremely alkaliphilic Bacillus species. One motif is the AXAXAXA sequence found in the N-terminal helix-1 instead of the GXGXGXG of non-alkaliphiles. Quadruple A-->G chromosomal mutants of alkaliphilic Bacillus pseudofirmus OF4 retain 50% of the wild-type hydrolytic activity (ATPase) but <18% of the ATP synthase capacity at high pH. Consistent with a structural impact of the four alanine replacements, the mutant ATPase activity showed enhanced inhibition by dicyclohexylcarbodiimide, which blocks the helix-2 carboxylate. Single, double, or triple A-->G mutants exhibited more modest defects, as monitored by malate growth. The key carboxylate is in the second motif, which is P(51)XXE(54)XXP in extreme alkaliphiles instead of the (A/G)XX(E/D)XXP found elsewhere. Mutation of Pro(51) to alanine had been shown to severely reduce malate growth and ATP synthesis at high pH. Here, two Pro(51) to glycine mutants of different severities retained ATP synthase capacity but exhibited growth deficits and proton leakiness. A Glu(54) to Asp(54) change increased proton leakiness and reduced malate growth 79-90%. The Pro(51) and the Glu(54) mutants were both more dicyclohexylcarbodiimide-sensitive than wild type. The results highlight the requirement for c-subunit adaptations to achieve alkaliphile ATP synthesis with minimal cytoplasmic proton loss and suggest partial suppression of some mutations by changes outside the atp operon.


Assuntos
Adaptação Fisiológica , Bacillus/enzimologia , Proteínas de Bactérias/metabolismo , Motivos de Aminoácidos/fisiologia , Substituição de Aminoácidos , Bacillus/genética , Proteínas de Bactérias/genética , ATPases Bacterianas Próton-Translocadoras , Domínio Catalítico/fisiologia , Dicicloexilcarbodi-Imida/farmacologia , Mutação , Fases de Leitura Aberta/fisiologia , Óperon/fisiologia
18.
Proc Natl Acad Sci U S A ; 104(33): 13289-94, 2007 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-17679694

RESUMO

Properties of four two-component bacterial transport systems of the cation/proton antiporter-2 (CPA2) family led to suggestions that this CPA2 subset may use a channel rather than an antiport mechanism [see Booth IR, Edwards MD, Gunasekera B, Li C, Miller S (2005) in Bacterial Ion Channels, eds Kubalski A, Martinac B (Am Soc Microbiol, Washington, DC), pp 21-40]. The transporter subset includes the intensively studied glutathione-gated K(+) efflux systems from Escherichia coli, KefGB, and KefFC. KefG and KefF are ancillary proteins. They are peripheral membrane proteins that are encoded in operons with the respective transporter proteins, KefB and KefC, and are required for optimal efflux activity. The other two-component CPA2 transporters of the subset are AmhMT, an NH(4)(+) (K(+)) efflux system from alkaliphilic Bacillus pseudofirmus OF4; and YhaTU, a K(+) efflux system from Bacillus subtilis. Here a K(+)/H(+) antiport capacity was demonstrated for YhaTU, AmhMT, and KefFC in membrane vesicles from antiporter-deficient E. coli KNabc. The apparent K(m) for K(+) was in the low mM range. The peripheral protein was required for YhaU- and KefC-dependent antiport, whereas both AmhT and AmhMT exhibited antiport. KefFC had the broadest range of substrates, using Rb(+) approximately K(+)>Li(+)>Na(+). Glutathione significantly inhibited KefFC-mediated K(+)/H(+) antiport in vesicles. The inhibition was enhanced by NADH, which presumably binds to the KTN/RCK domain of KefC. The antiport mechanism accounts for the H(+) uptake involved in KefFC-mediated electrophile resistance in vivo. Because the physiological substrate of AmhMT in the alkaliphile is NH(4)(+), the results also imply that AmhMT catalyzes NH(4)(+)/H(+) antiport, which would prevent net cytoplasmic H(+) loss during NH(4)(+) efflux.


Assuntos
Cátions Monovalentes/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Prótons , Clonagem Molecular , Glutationa/fisiologia , NAD/metabolismo
19.
Nihon Hinyokika Gakkai Zasshi ; 98(1): 9-16, 2007 Jan.
Artigo em Japonês | MEDLINE | ID: mdl-17302289

RESUMO

OBJECTIVE: Stone analysis is an important examination for treatment and prevention of recurrence in urolithiasis. A twenty-six years clinical study of patient with urinary stone formers performed stone analysis was conducted. MATERIALS AND METHODS: 1,108 stone formers (male 726, female 382) who performed stone analysis from 1977 to 2002 was conducted. Location of the stone, sex, age, treatment and stone analysis was examined in this study. Phase 1 is from 1977 to 1983 mainly performed open surgery, phase 2 is from 1984 to 1992 mainly performed endoscopic surgery, and phase 3 is from 1993 to 2002 mainly performed extracorporeal shock wave lithotripsy (SWL). RESULTS: Analytic numbers per year increased, especially phase 3. In the treatment of upper urinary tract (UUT) stone, open surgery, endoscopic surgery and SWL was carried out 78.4%, 72.8% and 71.4% of all cases in each phase. Many transurethral lithotripsy were performed for lower urinary tract (LUT) stone. The numbers of UUT and LUT stone were 1,007 and 101 cases. The frequency of LUT stone was higher than that found in a nationwide urolithiasis survey carried out in Japan in 1995. The male-female ratio of UUT stone was 2.35:1, 1.74:1 in phase 2 and 3. The frequency of female increased in phase 2 more than that in phase 3. The incidence of calcium oxalate stone was increased, calcium phosphate stone and infectious stone was significantly decreased in UUT and calcium containing stone in LUT was decreased. The average age for incidence of UUT stone rose in man step by step. The frequency in male was significantly higher than that in female under 50's, not significantly higher over 50's in calcium oxalate with calcium phosphate stone former (p = 0.009). CONCLUSION: In the present study, the clinical features were as follows : important urinary stone analysis, high frequency of LUT stone, high frequency in females, tendency to aging, high frequency of calcium containing stone in LUT, resolution of the difference in male and female over 50's in calcium oxalate with calcium phosphate stone former.


Assuntos
Oxalato de Cálcio/análise , Fosfatos de Cálcio/análise , Litotripsia , Cálculos Urinários/química , Urolitíase/terapia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Endoscopia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Hiperplasia Prostática/complicações , Recidiva , Fatores Sexuais , Bexiga Urinaria Neurogênica/complicações , Cálculos Urinários/terapia , Urolitíase/etiologia , Urolitíase/prevenção & controle , Urolitíase/cirurgia
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