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1.
Int J Mol Sci ; 24(13)2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37446171

RESUMO

Maintaining optimal one-carbon metabolism (OCM) is essential for health and pregnancy. In this cross-sectional study, folate status was assessed based on 5-methyltetrahydrofolate (5-MTHF) levels, and the association between 5-MTHF and OCM-related metabolites was investigated in 227 female Japanese university students aged 18-25 years. The participants were divided into high and low 5-MTHF groups based on their folate status. Serum samples of the participants were collected while they were fasting, and 18 OCM-related metabolites were measured using stable-isotope dilution liquid chromatography-electrospray tandem mass spectrometry. The association between serum 5-MTHF and OCM-related metabolite concentrations was assessed using Spearman's rank correlation coefficient. Serum 5-MTHF concentrations were negatively correlated with total homocysteine (tHcy) concentrations and positively correlated with S-adenosylmethionine (SAM) and total cysteine (tCys) concentrations. Serum 5-MTHF concentrations demonstrated a stronger negative correlation with tHcy/tCys than with tHcy alone. The negative correlation between betaine and tHcy concentrations was stronger in the low 5-MTHF group than in the high 5-MTHF group. The 5-MTHF status could be linked to Hcy flux into the transsulfuration pathway via SAM. Therefore, the tHcy/tCys ratio may be a more sensitive indicator of the 5-MTHF status than tHcy alone. Furthermore, a low 5-MTHF status can enhance Hcy metabolism via betaine.


Assuntos
Betaína , Ácido Fólico , Gravidez , Humanos , Feminino , Adolescente , Adulto Jovem , Adulto , Estudos Transversais , S-Adenosilmetionina , Carbono , Homocisteína
2.
J Phys Ther Sci ; 35(6): 471-478, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37266364

RESUMO

[Purpose] This study aimed to extract knowledge for the development of a training program for creating a social model of disability for physical therapists, focusing on the experiential learning of those physical therapists who did not use acceptance of disability according to their subjective judgment. [Participants and Methods] The study included 11 physical therapists who were interviewed about their use of acceptance of disability and the circumstances leading to its non-use. [Results] The study identified the past and current use of acceptance of disability, as well as cases and reasons for its discontinuation, along with changes in clinical content. [Conclusion] The study extracted knowledge for the development of training programs in line with the components of the experiential learning model.

3.
BMC Ophthalmol ; 21(1): 241, 2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34053440

RESUMO

BACKGROUND: The effect of various reduced doses of verteporfin photodynamic therapy (PDT) on choroidal blood flow in chronic central serous chorioretinopathy (CSC) remains unclear. Therefore, this study aimed to evaluate choroidal blood flow after half-dose PDT (1/2PDT) and one-third dose PDT (1/3PDT) with verteporfin for chronic CSC using laser speckle flowgraphy and spectral-domain optical coherence tomography. METHODS: Twenty-seven eyes of 27 patients with serous retinal detachment (SRD) caused by chronic CSC for more than 6 months were included in this study. Patients were divided into the 1/2PDT (n = 12; January 2018 to July 2019) and 1/3PDT (n = 15; August 2016 to December 2017) groups based on the treatment period. The best-corrected visual acuity (BCVA), central retinal thickness (CRT), central choroidal thickness (CCT), and mean blur rate in the macular area (m-MBR) and optic nerve head (ONH-MBR) were obtained using laser speckle flowgraphy and evaluated at baseline (pre-treatment), and 2 weeks, 1 month, 3 months, and 6 months after treatment. RESULTS: We found that SRD disappeared after 1 month in 92 and 93% of patients' eyes in the 1/2PDT and 1/3PDT groups, respectively. Recurrence of SRD was observed in one eye at the 6-month follow-up after 1/2PDT and two eyes at the 3-month follow-up after 1/3PDT. No significant improvement was observed in baseline BCVA in the 1/3PDT and 1/2PDT groups. The average m-MBR against baseline significantly decreased at 2 weeks and 1, 3, and 6 months in the 1/2PDT group. The average m-MBR against baseline decreased significantly only at the 2 weeks follow-up in the 1/3PDT group. The average rate of change in the CCT against baseline decreased significantly throughout for up to 6 months in the 1/2PDT group and for up to 3 months in the 1/3PDT group. No significant fluctuation was observed in the ONH-MBR. CONCLUSIONS: Here, PDT significantly affected choroidal blood flow depending on the verteporfin dose in chronic CSC. TRIAL REGISTRATION: This trial was retrospectively registered ( UMIN000026850 ; Approval date 03/04/2017).


Assuntos
Coriorretinopatia Serosa Central , Fotoquimioterapia , Coriorretinopatia Serosa Central/diagnóstico , Coriorretinopatia Serosa Central/tratamento farmacológico , Angiofluoresceinografia , Humanos , Fármacos Fotossensibilizantes/uso terapêutico , Verteporfina/uso terapêutico , Acuidade Visual
4.
Nihon Ronen Igakkai Zasshi ; 58(1): 70-80, 2021.
Artigo em Japonês | MEDLINE | ID: mdl-33627565

RESUMO

PURPOSE: This study aimed to clarify the effects of dementia care mapping (DCM) for one year in a healthcare center for older adults. DCM was conducted between September 2016 and August 2017. The care staff include nurses and caregivers in a narrow sense, medical staff, such as a physician, physical therapists, and occupational therapists worked on DCM as care staff in this study. RESULTS: There were 24 participants, with an average work experience of 7.21 (±4.74) years. In comparison to the baseline evaluation, the final assessment of self-efficacy through person-centred care showed significant improvement in 'Forecasting and Problem Solving on the Job' within 'Perceived Job Competence of Care Workers'. Six main categories of content were extracted from focus group interviews: 'Awareness,' 'Change of Elderly People under the Care of Staff throughout the Development of Mapping', 'Affirmative Feelings of Care Staff for Mapping', 'Negative Feelings for Mapping', 'Need for the Efficacy and Efficiency of the Mapping', and 'Mapping Based on the Age of the Participant and Future Prospects for Mapping'. The results of person-centred care showed that both the older patients and the staff noticed changes through the development of mapping. CONCLUSION: The developmental evaluation, based on collaboration by medical and welfare staff can improve self-efficacy through the practice of person-centred care and improves the ability to solve problems during the provision of care.


Assuntos
Demência , Serviços de Saúde para Idosos , Idoso , Demência/terapia , Pessoal de Saúde , Humanos , Assistência Centrada no Paciente , Autocuidado
5.
Nature ; 465(7296): 346-9, 2010 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-20485435

RESUMO

Commensal bacteria are known to inhibit pathogen colonization; however, complex host-microbe and microbe-microbe interactions have made it difficult to gain a detailed understanding of the mechanisms involved in the inhibition of colonization. Here we show that the serine protease Esp secreted by a subset of Staphylococcus epidermidis, a commensal bacterium, inhibits biofilm formation and nasal colonization by Staphylococcus aureus, a human pathogen. Epidemiological studies have demonstrated that the presence of Esp-secreting S. epidermidis in the nasal cavities of human volunteers correlates with the absence of S. aureus. Purified Esp inhibits biofilm formation and destroys pre-existing S. aureus biofilms. Furthermore, Esp enhances the susceptibility of S. aureus in biofilms to immune system components. In vivo studies have shown that Esp-secreting S. epidermidis eliminates S. aureus nasal colonization. These findings indicate that Esp hinders S. aureus colonization in vivo through a novel mechanism of bacterial interference, which could lead to the development of novel therapeutics to prevent S. aureus colonization and infection.


Assuntos
Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Nariz/microbiologia , Serina Proteases/metabolismo , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus epidermidis/enzimologia , Staphylococcus epidermidis/fisiologia , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/farmacologia , Feminino , Humanos , Masculino , Razão de Chances , Serina Proteases/química , Serina Proteases/deficiência , Serina Proteases/isolamento & purificação , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/prevenção & controle , Infecções Estafilocócicas/terapia , Staphylococcus aureus/imunologia , Staphylococcus epidermidis/genética , Superinfecção/imunologia , Superinfecção/microbiologia , Superinfecção/prevenção & controle , Superinfecção/terapia , Adulto Jovem , beta-Defensinas/imunologia , beta-Defensinas/farmacologia
6.
J Bacteriol ; 195(8): 1645-55, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23316041

RESUMO

Staphylococcus aureus exhibits a strong capacity to attach to abiotic or biotic surfaces and form biofilms, which lead to chronic infections. We have recently shown that Esp, a serine protease secreted by commensal Staphylococcus epidermidis, disassembles preformed biofilms of S. aureus and inhibits its colonization. Esp was expected to degrade protein determinants of the adhesive and cohesive strength of S. aureus biofilms. The aim of this study was to elucidate the substrate specificity and target proteins of Esp and thereby determine the mechanism by which Esp disassembles S. aureus biofilms. We used a mutant Esp protein (Esp(S235A)) with defective proteolytic activity; this protein did not disassemble the biofilm formed by a clinically isolated methicillin-resistant S. aureus (MRSA) strain, thereby indicating that the proteolytic activity of Esp is essential for biofilm disassembly. Esp degraded specific proteins in the biofilm matrix and cell wall fractions, in contrast to proteinase K, which is frequently used for testing biofilm robustness and showed no preference for proteolysis. Proteomic and immunological analyses showed that Esp degrades at least 75 proteins, including 11 biofilm formation- and colonization-associated proteins, such as the extracellular adherence protein, the extracellular matrix protein-binding protein, fibronectin-binding protein A, and protein A. In addition, Esp selectively degraded several human receptor proteins of S. aureus (e.g., fibronectin, fibrinogen, and vitronectin) that are involved in its colonization or infection. These results suggest that Esp inhibits S. aureus colonization and biofilm formation by degrading specific proteins that are crucial for biofilm construction and host-pathogen interaction.


Assuntos
Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Serina Proteases/metabolismo , Staphylococcus aureus/fisiologia , Staphylococcus epidermidis/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas Sanguíneas/química , Parede Celular , Matriz Extracelular/química , Interações Hospedeiro-Patógeno , Humanos , Proteínas de Membrana/metabolismo , Microscopia de Fluorescência , Serina Proteases/química , Serina Proteases/genética , Cloreto de Sódio , Staphylococcus aureus/ultraestrutura , Staphylococcus epidermidis/enzimologia , Staphylococcus epidermidis/genética , Especificidade por Substrato
7.
Antimicrob Agents Chemother ; 57(11): 5572-9, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23979748

RESUMO

Control of biofilms formed by microbial pathogens is an important subject for medical researchers, since the development of biofilms on foreign-body surfaces often causes biofilm-associated infections in patients with indwelling medical devices. The present study examined the effects of different kinds of bacteriocins, which are ribosomally synthesized antimicrobial peptides produced by certain bacteria, on biofilms formed by a clinical isolate of methicillin-resistant Staphylococcus aureus (MRSA). The activities and modes of action of three bacteriocins with different structures (nisin A, lacticin Q, and nukacin ISK-1) were evaluated. Vancomycin, a glycopeptide antibiotic used in the treatment of MRSA infections, showed bactericidal activity against planktonic cells but not against biofilm cells. Among the tested bacteriocins, nisin A showed the highest bactericidal activity against both planktonic cells and biofilm cells. Lacticin Q also showed bactericidal activity against both planktonic cells and biofilm cells, but its activity against biofilm cells was significantly lower than that of nisin A. Nukacin ISK-1 showed bacteriostatic activity against planktonic cells and did not show bactericidal activity against biofilm cells. Mode-of-action studies indicated that pore formation leading to ATP efflux is important for the bactericidal activity against biofilm cells. Our results suggest that bacteriocins that form stable pores on biofilm cells are highly potent for the treatment of MRSA biofilm infections.


Assuntos
Antibacterianos/farmacologia , Bacteriocinas/farmacologia , Biofilmes/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Nisina/farmacologia , Proteínas Citotóxicas Formadoras de Poros/farmacologia , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Antibacterianos/química , Bacteriocinas/química , Biofilmes/crescimento & desenvolvimento , Humanos , Staphylococcus aureus Resistente à Meticilina/crescimento & desenvolvimento , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Nisina/química , Plâncton/efeitos dos fármacos , Plâncton/crescimento & desenvolvimento , Proteínas Citotóxicas Formadoras de Poros/química , Relação Estrutura-Atividade , Vancomicina/farmacologia
8.
Appl Environ Microbiol ; 79(7): 2328-35, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23354720

RESUMO

ATP modulates immune cell functions, and ATP derived from gut commensal bacteria promotes the differentiation of T helper 17 (Th17) cells in the intestinal lamina propria. We recently reported that Enterococcus gallinarum, isolated from mice and humans, secretes ATP. We have since found and characterized several ATP-secreting bacteria. Of the tested enterococci, Enterococcus mundtii secreted the greatest amount of ATP (>2 µM/10(8) cells) after overnight culture. Glucose, not amino acids and vitamins, was essential for ATP secretion from E. mundtii. Analyses of energy-deprived cells demonstrated that glycolysis is the most important pathway for bacterial ATP secretion. Furthermore, exponential-phase E. mundtii and Enterococcus faecalis cells secrete ATP more efficiently than stationary-phase cells. Other bacteria, including Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, also secrete ATP in exponential but not stationary phase. These results suggest that various gut bacteria, including commensals and pathogens, might secrete ATP at any growth phase and modulate immune cell function.


Assuntos
Trifosfato de Adenosina/metabolismo , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Trato Gastrointestinal/microbiologia , Glucose/metabolismo , Animais , Bactérias/isolamento & purificação , Camundongos
9.
Nutrients ; 15(22)2023 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-38004134

RESUMO

Homocysteine is a methionine metabolism intermediate and its increased blood levels are associated with a higher risk of noncommunicable diseases. Reportedly, blood homocysteine levels increase with inadequate folate, vitamin B6, and vitamin B12 intake; however, its relationship with dietary factors other than these three vitamins remains unknown. Thus, we investigated the relationship of homocysteine with other nutrient intake. We performed a dietary survey on 227 young women using a food record with approximate amounts for 7 consecutive days in conjunction with digital imaging. We collected early morning fasting blood samples the day after the dietary survey was completed and analyzed the serum homocysteine levels. We observed that the serum homocysteine concentrations were significantly negatively associated with soluble, insoluble, and total fiber intake. In addition, participants with high fruit and mushroom intake displayed lower serum homocysteine concentrations, suggesting dietary fiber involvement from these foods. However, we observed no serum homocysteine concentration-related association with cereals and vegetables (well-documented dietary fiber sources) or with fruits and mushrooms. In conclusion, fiber quality-related differences could thus be caused by different sources, including antioxidant components such as fruit polyphenols and mushroom antioxidant and anti-inflammatory factors.


Assuntos
Dieta , População do Leste Asiático , Homocisteína , Feminino , Humanos , Antioxidantes , Fibras na Dieta , Ácido Fólico , Homocisteína/sangue , Vitamina B 12 , Vitaminas
10.
Infect Immun ; 79(6): 2215-23, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21422173

RESUMO

Fibronectin-binding protein A (FnBPA) and FnBPB are important adhesins for Staphylococcus aureus infection. We constructed fnbA and/or fnbB mutant strains from S. aureus SH1000, which possesses intact rsbU, and studied the role of these adhesins in in vitro and in vivo infections. In intravenous infection, all fnb mutants caused a remarkable reduction in the colonization rate in kidneys and the mortality rate of mice. fnbB mutant caused a more severe decrease in body weight than that caused by fnbA mutant. Serum levels of interleukin-6 and nuclear factor κB (NF-κB) activation in spleen cells were remarkably reduced in fnbA or fnbA fnbB mutant infections; however, there was no significant reduction in fnbB mutant infections. In in vitro cellular infection, FnBPA was shown to be indispensable for adhesion to and internalization by nonprofessional phagocytic cells upon ingestion by inflammatory macrophages and NF-κB activation. However, both FnBPs were required for efficient cellular responses. The results showed that FnBPA is more important for in vitro and in vivo infections; however, cooperation between FnBPA and FnBPB is indispensable for the induction of severe infection resulting in septic death.


Assuntos
Adesinas Bacterianas/fisiologia , Sepse/microbiologia , Infecções Estafilocócicas/metabolismo , Staphylococcus aureus/fisiologia , Adesinas Bacterianas/metabolismo , Animais , Western Blotting , Feminino , Imunidade Celular , Interleucina-6/sangue , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , NF-kappa B/sangue , Fagócitos/imunologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sepse/metabolismo , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/imunologia , Staphylococcus aureus/metabolismo
11.
Inorg Chem ; 50(19): 9337-44, 2011 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-21888332

RESUMO

The electrochemical oxidation of an acetone solution containing [Mn(III) (5-MeOsaltmen)(H(2)O)](2)(PF(6))(2) (5-MeOsaltmen(2-) = N,N'-(1,1,2,2-tetramethylethylene)bis(5-methoxysalicylideneiminate)) and (NBu(4))[Ni(dmit)(2)] (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate) afforded a hybrid material, [Mn(5-MeOsaltmen)(acetone)](2)[Ni(dmit)(2)](6) (1), in which [Mn(2)](2+) single-molecule magnets (SMMs) with an S(T) = 4 ground state and [Ni(dmit)(2)](n-) molecules in a charge-ordered state (n = 0 or 1) are assembled in a layer-by-layer structure. Compound 1 crystallizes in the triclinic space group P1 with an inversion center at the midpoint of the Mn···Mn dimer. The [Mn(2)](2+) unit has a typical nonplanar Mn(III) dimeric core and is structurally consistent with previously reported [Mn(2)] SMMs. The six [Ni(dmit)(2)](n-) (n = 0 or 1) units have a square-planar coordination geometry, and the charge ordering among them was assigned on the basis of ν(C═C) in IR reflectance spectra (1386, 1356, 1327, and 1296 cm(-1)). The [Mn(2)](2+) SMM and [Ni(dmit)(2)](n-) units aggregate independently to form hybrid frames. Electronic conductivity measurements revealed that 1 behaved as a semiconductor (ρ(rt) = 2.1 × 10(-1) Ω·cm(-1), E(a) = 97 meV) at ambient pressure and as an insulator at 1.7 GPa (ρ(1.7GPa) = 4.5 Ω·cm(-1), E(a) = 76 meV). Magnetic measurements indicated that the [Mn(2)](2+) units in 1 behaved as S(T) = 4 SMMs at low temperatures.

12.
J Clin Microbiol ; 48(5): 1949-51, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20305009

RESUMO

In a recent report, ATP, which was possibly secreted by some intestinal bacteria, was shown to cause colitis in mice via Th17 cell differentiation. However, the ATP-secreting bacteria have not been isolated and identified. In the present study, we report that Enterococcus gallinarum, which is a vancomycin-resistant Gram-positive coccus isolated from mice and humans, secretes ATP.


Assuntos
Trifosfato de Adenosina/metabolismo , Enterococcus/isolamento & purificação , Enterococcus/metabolismo , Trato Gastrointestinal/microbiologia , Animais , Humanos , Camundongos , Camundongos Endogâmicos BALB C
13.
Infect Immun ; 77(1): 327-34, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18936175

RESUMO

Neutrophils play a crucial role in the host response to infection with Staphylococcus aureus, which is a major human pathogen capable of causing life-threatening disease. Interleukin-8 (IL-8) is a potent chemoattractant and activator of neutrophils. We previously reported that S. aureus secretes a factor that suppresses IL-8 production by human endothelial cells. Here we isolated an inhibitor of IL-8 production from the supernatant and identified it as staphylococcal beta-hemolysin. Beta-hemolysin reduced IL-8 production without cytotoxicity to endothelial cells. Pretreatment with beta-hemolysin decreased the expression of both IL-8 mRNA and protein induced by tumor necrosis factor alpha (TNF-alpha). Migration of neutrophils across TNF-alpha-activated endothelium was also inhibited by beta-hemolysin. In contrast, beta-hemolysin had no effect on intercellular adhesive molecule 1 expression in activated endothelial cells. These results showed that beta-hemolysin produced by S. aureus interferes with inflammatory signaling in endothelial cells and may help S. aureus evade the host immune response.


Assuntos
Toxinas Bacterianas/toxicidade , Células Endoteliais/microbiologia , Proteínas Hemolisinas/toxicidade , Interleucina-8/antagonistas & inibidores , Neutrófilos/imunologia , Esfingomielina Fosfodiesterase/toxicidade , Staphylococcus aureus/imunologia , Ensaios de Migração de Leucócitos , Células Cultivadas , Humanos
14.
J Microbiol Methods ; 145: 93-97, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29288674

RESUMO

Cellular glycogen levels reflect the activity of RpoS, an important stress-inducible bacterial sigma factor known to regulate several stress-resistance related genes, such as katE, encoding hydroperoxidase II (HPII), and the glg genes, encoding glycogen synthesis enzymes, in Escherichia coli. In this study, a straightforward assay for measuring glycogen levels and RpoS activity was developed combining the ease and simplicity of qualitative approaches. The assay reagent was a 2% iodine solution (2% iodine/1M NaOH), and the basic principle of this assay is the iodine-glycogen reaction, which produces a reddish brown color that can be measured using a spectrophotometer. A calibration plot using a known amount of glycogen yielded the best linear fit over a range of 10-300µg/assay (R2=0.994). The applicability of the assay for measuring the glycogen level of various samples was assessed using a wild type (WT) E. coli K-12 strain, glycogen- and RpoS-deficient isogenic mutants, and clinical bacterial isolates with or without RpoS activity; the assay generated reproducible results. Additionally, the assay was successfully applied for measuring glycogen levels in human cells. In conclusion, we developed a straightforward and cost-effective assay for measuring glycogen levels, which can be applied for measuring RpoS activity.


Assuntos
Proteínas de Bactérias/metabolismo , Bioensaio/métodos , Escherichia coli K12/fisiologia , Glicogênio/análise , Fator sigma/metabolismo , Proteínas de Bactérias/genética , Catalase/metabolismo , Colorimetria , Escherichia coli K12/efeitos dos fármacos , Escherichia coli K12/genética , Humanos , Iodo/farmacologia , Mutação , Células PC-3 , Sensibilidade e Especificidade , Fator sigma/genética , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética
15.
Front Microbiol ; 8: 656, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28491053

RESUMO

RpoS is a key stress-inducible sigma factor that regulates stress resistance genes in Escherichia coli, such as the katE gene encoding catalase HPII and the glg genes encoding glycogen synthesis proteins. Monitoring RpoS activity can provide information on the stress sensitivity of E. coli isolates in clinical settings because the RpoS in these isolates is often mutated. In the present study, we found a novel, missense point mutation at RpoS residue 128 in a clinical Shiga toxin-producing E. coli (STEC) isolate. This mutation caused RpoS dysfunction and increased stress sensitivity. A mutant rpoS was cloned from a clinical STEC that is vulnerable to cold temperature and oxidative stresses. Mutant RpoS protein expression was detected in the clinical isolate, and this RpoS was non-functional according to HPII activity and glycogen levels, which are positively regulated by RpoS and thus are used as indicators for RpoS function. A reporter assay with ß-galactosidase indicated that the dysfunction occurred at the transcriptional level of genes regulated by RpoS. Furthermore, substitution analysis indicated that the hydrophobicity of the amino acid at residue 128 was critical for RpoS activity; the simulation analysis indicated that the amino acids of RNA polymerase (RNAP) that interact with RpoS residue 128 are hydrophobic, suggesting that this hydrophobic interaction is critical for RpoS activity. In addition, substitution of Ile128 to Pro128 abolished RpoS activity, possibly as a result of disruption of the secondsary structure around residue 128, indicating that the structure is also a crucial factor for RpoS activity. These results indicate that only one point mutation at a hydrophobic residue of the complex formed during transcription leads to a critical change in RpoS regulation. Moreover, we found that Ile128 is widely conserved among various bacteria: several bacterial strains have Met128 or Leu128, which are hydrophobic residues, and these strains had similar or higher RpoS activity than that observed with Ile128 in this study. These data indicate that the hydrophobicity of the amino acid at residue 128 is critical for RpoS activity and is consequently important for bacterial survival. Taken together, these findings may contribute to a deeper understanding of protein functional mechanisms and bacterial stress responses.

16.
Sci Adv ; 3(8): e1601594, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28819640

RESUMO

The Mott transition-a metal-insulator transition caused by repulsive Coulomb interactions between electrons-is a central issue in condensed matter physics because it is the mother earth of various attractive phenomena. Outstanding examples are high-Tc (critical temperature) cuprates and manganites exhibiting colossal magnetoresistance. Furthermore, spin liquid states, which are quantum-fluctuation-driven disordered ground states in antiferromagnets, have recently been found in magnetic systems very near the Mott transition. To date, intensive studies on the Mott transition have been conducted and appear to have established a nearly complete framework for understanding the Mott transition. We found an unknown type of Mott transition in an organic spin liquid material with a slightly disordered lattice. Around the Mott transition region of this material under pressure, nuclear magnetic resonance experiments capture the emergence of slow electronic fluctuations of the order of kilohertz or lower, which is not expected in the conventional Mott transition that appears as a clear first-order transition at low temperatures. We suggest that they are due to the unconventional metal-insulator fluctuations emerging around the disordered Mott transition in analogy to the slowly fluctuating spin phase, or Griffiths phase, realized in Ising spin systems with disordered lattices.

17.
Sci Rep ; 3: 3081, 2013 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-24170119

RESUMO

In this study, an assay that combines the ease and simplicity of the qualitative approach for measuring catalase activity was developed. The assay reagents comprised only hydrogen peroxide and Triton X-100. The enzyme-generated oxygen bubbles trapped by Triton X-100 were visualized as foam, whose height was estimated. A calibration plot using the defined unit of catalase activity yielded the best linear fit over a range of 20-300 units (U) (y = 0.3794x - 2.0909, r(2) = 0.993). The assay precision and reproducibility at 100 U were 4.6% and 4.8%, respectively. The applicability of the assay for measuring the catalase activity of various samples was assessed using laboratory strains of Escherichia coli, catalase-deficient isogenic mutants, clinically isolated Shiga toxin-producing E. coli, and human cells. The assay generated reproducible results. In conclusion, this new assay can be used to measure the catalase activity of bacterial isolates and human cells.


Assuntos
Catalase/metabolismo , Ensaios Enzimáticos/métodos , Linhagem Celular , Ativação Enzimática , Humanos
18.
Microbiol Immunol ; 51(1): 63-71, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17237600

RESUMO

Many pathogens colonize host tissues by binding to the extracellular matrix via their cell surface adhesion molecules, which are called MSCRAMMs (microbial surface components recognizing adhesive matrix molecules). Staphylococcus aureus expresses several of these adhesion molecules, some of which bind to fibronectin. Of these adhesion molecules, fibronectin-binding proteins play a role in the pathogenicity of S. aureus, although it is not yet clear whether they enhance its virulence. We have previously shown that fibronectin-bound S. aureus is efficiently phagocytosed by thioglycolate-induced mouse peritoneal macrophages. Bacterial ingestion is mediated by Very Late Antigen-5 (VLA-5; alpha5beta1 integrin) and is accompanied by the formation of adhesion complexes. Here we show that the expression of VLA-5 is restricted to thioglycolate-induced inflammatory macrophages and is not found in the resident macrophages. When cells were in suspension, alpha5 integrin was not expressed on the surface of either resident or inflammatory macrophages, whereas in adherent cells, this integrin was distributed on the surface of inflammatory but not resident macrophages. A high level of this integrin was present in the cytoplasmic region only in inflammatory macrophages. In agreement with this, fibronectin-mediated phagocytosis of S. aureus was observed only in the inflammatory macrophages. In inflammatory macrophages ingesting fibronectin-bound S. aureus, alpha5 integrin was concentrated close to the phagocytosed bacteria. This change in distribution was not found in macrophages ingesting untreated bacteria. Together with our previous work, these results indicate that, upon ingestion of fibronectin-bound S. aureus, VLA-5 accumulates in the area of phagocytosis in inflammatory macrophages, where it forms adhesion complexes.


Assuntos
Integrina alfa5beta1/metabolismo , Macrófagos Peritoneais/imunologia , Fagocitose , Staphylococcus aureus/imunologia , Animais , Antígenos de Superfície/análise , Células Cultivadas , Citoplasma/química , Feminino , Fibronectinas/metabolismo , Citometria de Fluxo , Expressão Gênica , Histocitoquímica , Integrina alfa5beta1/biossíntese , Camundongos , Microscopia de Fluorescência
19.
J Am Chem Soc ; 128(31): 10016-7, 2006 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-16881622

RESUMO

Pressure-induced superconducting behavior was found in two anion radical salts, EtMe3Z[Pd(dmit)2]2 (dmit = 1,3-dithiole-2-thione-4,5-dithiolate, Z = P, As), that are Mott insulators and exhibit different magnetic and structural transitions at ambient pressure.

20.
Infect Immun ; 71(1): 140-6, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12496159

RESUMO

Staphylococcus aureus Cowan I and a clinically isolated coagulase-negative Staphylococcus strain, S. saprophyticus 10312, were found to have two fibronectin binding proteins, FnBPA and FnBPB. While both staphylococci bound to serum fibronectin to a similar extent, fibronectin binding significantly increased the phagocytic activity of macrophages against S. aureus (by ca. 150%) but not against S. saprophyticus. This enhancing effect of fibronectin was inhibited by an RGD sequence-containing peptide and also by anti-very late antigen 5 antibody. This suggests that the effect is mediated by very late antigen 5 expressed on macrophages. In macrophages ingesting fibronectin-bound Cowan I, alpha(5) and beta(1) chains were associated with the cytoskeleton. Cytosolic signaling factors such as paxillin, c-Src, and c-Csk were also associated with the cytoskeleton. On the contrary, beta(3) integrin transiently disappeared from the cytoskeleton when macrophages ingested the fibronectin-treated S. aureus Cowan I. Furthermore, the Src kinase family tyrosine kinase Lyn dissociated from the cytoskeleton. These cellular components did not respond in a fibronectin-dependent manner when macrophages phagocytosed S. saprophyticus. This means that only fibronectin-treated S. aureus Cowan I induces the accumulation of very late antigen 5, which in turn induces the association of paxillin and tyrosine kinases. It is thought that the phagocytic activity of macrophages against fibronectin-treated S. aureus was increased by signaling via the activation of very late antigen 5.


Assuntos
Citoesqueleto/metabolismo , Fibronectinas/metabolismo , Integrina alfa5beta1/metabolismo , Macrófagos Peritoneais/imunologia , Fagocitose , Transdução de Sinais , Staphylococcus aureus/metabolismo , Animais , Proteínas do Citoesqueleto/metabolismo , Feminino , Humanos , Macrófagos Peritoneais/metabolismo , Camundongos , Paxilina , Fosfoproteínas/metabolismo , Proteínas Tirosina Quinases/metabolismo , Staphylococcus aureus/imunologia
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