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1.
Heliyon ; 9(7): e18092, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37539116

RESUMO

The use of radiant panels in homes has increased recently because they do not cause a drafty feeling, unlike air conditioners. However, air conditioners are more power-efficient than radiant panels and have a higher coefficient of performance (COP). Therefore, combining radiant panels and air conditioning can provide an optimal solution for thermal control in residences. Energy simulation (ES) and computational fluid dynamics (CFD) can be used to simulate such environments. ES is suitable for non-steady state calculations, and combined with appropriate modeling, enables an accurate estimation of power consumption. Effective dehumidification becomes necessary, during summer as the relative humidity in a room increases. Both air conditioners and radiant panels can achieve this. This study developed a simulation tool that incorporates the effects of dehumidification. Based on a relative evaluation, a case was proposed where both energy efficiency and comfort were satisfied by jointly using air conditioners and radiant panels. The study found that a small number of panels could achieve the most balanced operation. The results of this study can serve as a reference for general housing, and the developed simulation tool can be applied to product development and building material design.

2.
Microbiol Spectr ; 10(2): e0056122, 2022 04 27.
Artigo em Inglês | MEDLINE | ID: mdl-35348372

RESUMO

This study details a unique process of autothermal thermophilic aerobic digestion (ATAD) of human excreta useful in producing nitrogen-rich and pathogen-free organic fertilizer. The process was divided into initial, middle, and final phases, based on changes in temperature, dissolved oxygen (DO), and bacterial community structure. The aim of this study was to determine bacterial factors that would affect liquid fertilizer production in the process, using shotgun metagenomic analysis of each phase. Although the abundances of all 28 gene categories include 4 categories in SEED subsystems level 1 were similar to those in another type of wastewater treatment system, the abundances of 4 gene categories changed remarkably. Among them, a decrease in the abundance of the phage-related gene category and the presence of antibacterial substances in secondary metabolism may explain the change in bacterial community structure from the material to the initial phase. Increases in the abundances of two gene categories, phage-related and secondary metabolism, coincided with a decrease in alpha diversity from the material to the initial phase. A potential increase in the abundance of genes in the category of sporulation from the middle to the final phase was correlated with deterioration of growth conditions and stabilization processes. In addition, prompt consumption of short-chain fatty acids in the initial phase and unusually stable ammonia accumulation throughout the process could be explained by the presence/absence of related metabolic genes. In conclusion, the relationships between bacterial function and unique characteristics of ATAD were revealed; our findings support the enhancement of liquid fertilizer production from wastewater. IMPORTANCE Metagenome analysis was performed to determine the microbial dynamics of the unique autothermal thermophilic aerobic digestion process of human excreta, which includes initial, middle, and final phases. In this study, we revealed the details of functional genes related to physicochemical and bacterial characteristics in the ATAD process. Four gene categories showed increases and decreases during the digestion process. In addition, the unusual stable accumulation of ammonia and prompt consumption of short-chain fatty acids were explained by the absence or presence of related metabolic genes. In addition to revealing the relationships between bacteria and physicochemical properties, the results of this research may support improving wastewater management systems worldwide by using the ATAD process in liquid fertilizer production systems.


Assuntos
Esgotos , Eliminação de Resíduos Líquidos , Amônia/análise , Bactérias/genética , Biodegradação Ambiental , Reatores Biológicos/microbiologia , Digestão , Fertilizantes , Humanos , Metagenoma , Esgotos/microbiologia , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias
3.
Anesth Analg ; 132(6): 1756-1767, 2021 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-33857022

RESUMO

BACKGROUND: The transient receptor potential vanilloid subtype 3 (TRPV3) channel is activated by innocuous temperature and several chemical stimuli. It is proposed to be involved in pathological pain development and is therefore considered a potential target for treating pain. Local anesthetics have been used for patients with both acute and chronic pain. Although blockage of the voltage-gated sodium channel is the primary mechanism by which local anesthetics exert their effects, they cannot be explained by this mechanism alone, especially in pathologic states such as chronic pain. Indeed, the effects of local anesthetics on multiple targets involved in the pain pathway have been reported. It has also been suggested that modulating the function of transient receptor potential (TRP) channels (eg, TRPV1 and transient receptor potential ankyrin 1 [TRPA1]) is one of the mechanisms of action of local anesthetics. However, the effects of local anesthetics on TRPV3 have not been reported. METHODS: We expressed TRPV3 in Xenopus oocytes and investigated the effects of local anesthetics on 2-aminoethoxydiphenyl borate (2APB)-induced currents using 2-electrode voltage-clamp techniques. RESULTS: Clinically used local anesthetics inhibited the 2APB-activated currents from the TRPV3 channel in a concentration-dependent manner at pharmacologically relevant concentrations with half maximal inhibitory concentration (IC50) values of 2.5 (lidocaine), 1.4 (mepivacaine), 0.28 (ropivacaine), and 0.17 (bupivacaine) mmol/L, respectively. Conversely, these local anesthetics also directly induced currents at higher concentrations, although these currents were quite small compared to the 2APB-induced currents. We found that the inhibition of TRPV3 by lidocaine is noncompetitive and independent of intracellular signaling cascades. 2APB-induced TRPV3 currents were reduced by extracellular N-(2,6-dimethylphenylcarbamoylmethyl) triethylammonium bromide (QX-314) but not by intracellular QX-314 nor benzocaine. Moreover, lidocaine showed a use-dependent block in TRPV3 inhibition. Finally, QX-314 appeared to slightly permeate the activated TRPV3 channel pore based on examination of oocytes coexpressing TRPV3 and a sodium channel. These results suggest that local anesthetics could inhibit TRPV3 channel function by extracellular interactions of their charged forms with the channel pore. CONCLUSIONS: Local anesthetics inhibited TRPV3 2APB-induced currents at pharmacologically relevant concentrations when TRPV3 was expressed in Xenopus oocytes. These effects seem to occur via an extracellular interaction between the charged form of the anesthetic with the TRPV3 channel pore. These results help to elucidate the mechanisms of action of local anesthetics.


Assuntos
Anestésicos Locais/administração & dosagem , Oócitos/efeitos dos fármacos , Oócitos/fisiologia , Canais de Cátion TRPV/antagonistas & inibidores , Canais de Cátion TRPV/fisiologia , Potenciais de Ação/efeitos dos fármacos , Potenciais de Ação/fisiologia , Animais , Relação Dose-Resposta a Droga , Feminino , Xenopus laevis
4.
Dig Dis Sci ; 66(7): 2353-2361, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-32623550

RESUMO

BACKGROUND: Although the use of cold snare polypectomy (CSP) has spread rapidly, its safety for pedunculated (Ip) polyps remains controversial. In particular, the outcomes of hot snare polypectomy (HSP) and CSP for Ip polyps have not been previously compared. AIMS: This study evaluated whether the rate of delayed postpolypectomy bleeding (DPPB) after CSP for Ip polyps was higher than that after HSP for Ip polyps and compared other outcomes (the rates of immediate bleeding and pathological margins) between the HSP and CSP procedures. METHODS: A total of 5905 colorectal polyps in 4920 patients were resected at Omori Red Cross Hospital between October 2012 and June 2019. The polyps were divided into two groups: the HSP group (86 polyps, 64 patients) and the CSP group (102 polyps, 87 patients). The primary outcome measure was the incidence of DPPB. The secondary outcome measures were the incidences of immediate bleeding during the procedure and pathological margins of the resected specimen. RESULTS: The rate of immediate bleeding during CSP was significantly higher than that for the HSP group [38.2% (39/102) versus 3.5% (3/86); p < 0.001]. However, the rate of DPPB was significantly higher in the HSP group than in the CSP group [4.7% (4/86) versus 0% (0/102); p < 0.001]. The rate of DPPB after CSP was 0%. CONCLUSIONS: This is the first study to compare the outcomes of HSP and CSP for Ip polyps. CSP is safer than HSP for Ip polyps measuring < 10 mm in diameter.


Assuntos
Pólipos do Colo/patologia , Pólipos do Colo/cirurgia , Procedimentos Cirúrgicos do Sistema Digestório/efeitos adversos , Procedimentos Cirúrgicos do Sistema Digestório/instrumentação , Equipamentos Cirúrgicos , Procedimentos Cirúrgicos do Sistema Digestório/métodos , Eletrocoagulação , Humanos , Hemorragia Pós-Operatória/prevenção & controle , Fatores de Risco , Fatores de Tempo
5.
Int J Colorectal Dis ; 35(5): 859-867, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32112197

RESUMO

BACKGROUND: Although cold snare polypectomy (CSP) has spread rapidly, it still remains controversial whether CSP is safe for pedunculated (Ip) polyps. PURPOSE: The aim of this study was to evaluate whether CSP for Ip polyps measuring less than 10 mm in diameter might be associated with an increased rate of delayed post-polypectomy bleeding (DPPB). METHODS: A total of 1641 colorectal polyps in 634 patients were resected at Omori Red Cross Hospital between April 2018 and December 2018. The polyps were divided into two groups depending on the morphology: the Ip group (90 polyps), and the non-Ip group (1551 polyps). RESULTS: Among the 1641 polyps, there was no case of DPPB, including in the Ip group. Immediate bleeding occurred in a total of 101 (6.2%) cases. Polyp location in the rectum (OR (95% CI), 3.61 (1.843-7.092); p < 0.001), polyp diameter ≥ 6 mm (OR (95% CI), 2.65 (1.702-4.132); p < 0.001), Ip morphology (OR (95% CI), 15.66 (9.262-26.49); p < 0.001), and treatment with antithrombotic agents (OR (95% CI), 2.18 (1.358-3.501); p = 0.0012) were identified as significant risk factors for immediate bleeding. CONCLUSIONS: This is the first study conducted to examine the safety of CSP for Ip polyps measuring less than 10 mm in diameter. CSP can be performed with a high level of safety even for Ip polyps. Based on our findings, we believe that Ip polyps could be included as an indication for CSP. However, prospective, randomized studies are necessary to confirm our results.


Assuntos
Pólipos do Colo/patologia , Pólipos do Colo/cirurgia , Procedimentos Cirúrgicos do Sistema Digestório/efeitos adversos , Idoso , Feminino , Hemorragia/etiologia , Humanos , Masculino , Análise Multivariada , Fatores de Risco , Resultado do Tratamento
6.
J Pharmacol Sci ; 142(4): 140-147, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31982332

RESUMO

Carvacrol is the predominant monoterpene in essential oils from many aromatic plants. Several animal studies showing analgesic effects of carvacrol indicate potential of carvacrol as a new medication for patients with refractory pain. Voltage-gated sodium channels (Nav) are thought to have crucial roles in the development of inflammatory and neuropathic pain, but there is limited information about whether the analgesic mechanism of carvacrol involves Nav. We used whole-cell, two-electrode, voltage-clamp techniques to examine the effects of carvacrol on sodium currents in Xenopus oocytes expressing α subunits of Nav1.2, Nav1.3, Nav1.6, Nav1.7, and Nav1.8. Carvacrol dose-dependently suppressed sodium currents at a holding potential that induced half-maximal current. The half-maximal inhibitory concentration values for Nav1.2, Nav1.3, Nav1.6, Nav1.7, and Nav1.8 were 233, 526, 215, 367, and 824 µmol/L, respectively, indicating that carvacrol had more potent inhibitory effects towards Nav1.2 and Nav1.6 than Nav1.3, Nav1.7, and Nav1.8. Gating analysis showed a depolarizing shift of the activation curve and a hyperpolarizing shift of the inactivation curve in all five α subunits following carvacrol treatment. Furthermore, carvacrol exhibits a use-dependent block for all five α Nav subunits. These findings provide a better understanding of the mechanisms associated with the analgesic effect of carvacrol.


Assuntos
Cimenos/farmacologia , Oócitos/metabolismo , Bloqueadores do Canal de Sódio Disparado por Voltagem , Analgésicos , Animais , Xenopus
7.
Int J Colorectal Dis ; 34(9): 1563-1569, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31312890

RESUMO

BACKGROUND: Incomplete polyp resection (IPR) is recognized as a risk factor for interval colorectal cancer (ICC), and is, therefore, an important issue in polypectomy. Cold snare polypectomy (CSP) is a procedure that does not involve electrocautery and has no burn effect. Therefore, there is the possibility that the risk of ICC associated with IPR is higher in cases undergoing CSP than in those undergoing hot polypectomy. However, little is known about the risk factors for IPR after CSP. PURPOSE: Precise identification of the risk factors can lead to prevention of IPR after CSP. Therefore, we performed this observational study for accurate identification of the risk factors for IPR after CSP. METHODS: Medical records of a total of 501 patients with 1177 colorectal polyps that were resected at Omori Red Cross Hospital between October 2017 and March 2018 were retrospectively reviewed. The lateral and deep margins of the resected polyps were evaluated to check for the resection completeness. RESULTS: Among the 1177 polyp resections, 1163 were included in the final analysis. IPR was detected in 206 (17.7%) cases. Performance of the resection by a trainee (OR (95% CI) 1.87 (1.328-2.632); P < 0.001) was identified as an independent risk factor for IPR in patients undergoing CSP. CONCLUSIONS: Performance of the polypectomy by a trainee was identified as a significant risk factor for IPR in patients undergoing CSP. Prospective, randomized studies are necessary in the future to develop effective methods for the prevention/control of IPR after CSP.


Assuntos
Pólipos do Colo/cirurgia , Idoso , Feminino , Humanos , Masculino , Análise Multivariada , Fatores de Risco
8.
Dig Dis Sci ; 64(11): 3247-3255, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-30684074

RESUMO

BACKGROUND: With the aging of the population and rising incidence of thromboembolic events, the clinical use of antithrombotic agents is also increasing. There are few reports yet on the management of antithrombotic agent use in patients undergoing cold snare polypectomy (CSP). AIMS: The aim of this study was to evaluate whether continued administration of antithrombotic agents in patients undergoing CSP would be associated with an increased rate of delayed post-polypectomy bleeding (DPPB). METHODS: A total of 1177 colorectal polyps in 501 patients were resected at Omori Red Cross Hospital between October 2017 and March 2018. The polyps were divided into two groups depending on whether the patients received antithrombotic agent treatment or not: the antithrombotic group (911 polyps) and the no-antithrombotic group (266 polyps). RESULTS: Among the 1177 polyp resections, there was no case of DPPB, including in the antithrombotic group. Immediate bleeding occurred in a total of 63 (5.4%) cases. Polyp location in the rectum (OR (95% CI) 2.64 (1.223-5.679); p = 0.013), polyp size ≥ 6 mm (OR (95% CI) 4.64 (2.719-7.933); p < 0.001), polypoid growth pattern (OR (95% CI) 2.78 (1.607-4.793); p < 0.001), and antithrombotic agent use (OR (95% CI) 2.98 (1.715-5.183); p < 0.001) were identified as significant risk factors of immediate bleeding. CONCLUSIONS: Continued use of antithrombotic agents does not increase the risk of DPPB, even in those receiving multiple antithrombotic agents. Thus, it is safe to perform CSP even in multiple agent users. Prospective, randomized studies are necessary to confirm our results.


Assuntos
Colectomia/métodos , Pólipos do Colo/tratamento farmacológico , Pólipos do Colo/cirurgia , Fibrinolíticos/uso terapêutico , Reto/patologia , Reto/cirurgia , Idoso , Pólipos do Colo/diagnóstico , Feminino , Fibrinolíticos/farmacologia , Humanos , Masculino , Pessoa de Meia-Idade , Reto/efeitos dos fármacos , Estudos Retrospectivos , Resultado do Tratamento
9.
J Biosci Bioeng ; 126(2): 196-204, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29657124

RESUMO

Autothermal thermophilic aerobic digestion (ATAD) is conducted for stabilization of sludge waste and is driven by the action of various microorganisms under aerobic conditions. However, the mechanism controlling bacterial community changes during ATAD via three (initial, middle and final) phases is currently unclear. To investigate this mechanism, activity analysis and a microcosm assay with shaking were performed on a bacterial community during the initial, middle, and final phases of incubation. Cell lysis activities toward gram-negative bacteria, but not gram-positive bacteria, were detected in the ATAD samples in the middle and final phases. During shaking incubation in initial-phase samples at 30 °C, major operational taxonomic units (OTUs) related to Acinetobacter indicus and Arcobacter cibarius dramatically increased along with decreases in several major OTUs. In middle-phase samples at 45 °C, we observed a major alteration of OTUs related to Caldicellulosiruptor bescii and Aciditerrimonas ferrireducens, together with distinct decreases in several other OTUs. Final-phase samples maintained a stable bacterial community with major OTUs showing limited similarities to Heliorestis baculata, Caldicellulosiruptor bescii, and Ornatilinea apprima. In conclusion, the changes in the bacterial community observed during ATAD could be partially attributed to the cell lysis activity toward gram-negative bacteria in the middle and final phases. The microcosm assay suggested that certain physical factors, such as a high oxygen supply and shearing forces, also might contribute to bacterial community changes in the initial and middle phases, and to the stable bacterial community in the final phase of ATAD.


Assuntos
Técnicas de Cultura Celular por Lotes/métodos , Reatores Biológicos/microbiologia , Biotransformação , Esgotos/microbiologia , Temperatura , Eliminação de Resíduos Líquidos/métodos , Actinobacteria/citologia , Aerobiose , Bactérias/citologia
10.
Plant Dis ; 102(7): 1434-1444, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30673559

RESUMO

Effects of monosaccharide-amended soils on suppression of Rhizoctonia damping-off of sugar beet were compared under controlled experiments. Suppressive effects of glucose, fructose, sorbose, and xylose were significantly (P < 0.001) greater than that of galactose or mannose but the effect of sorbose was reduced by soil treatments with antibiotics. Saprotrophic growth of Rhizoctonia solani in the laimosphere also was suppressed by glucose, fructose, sorbose, and xylose, whereas only sorbose repressed pericarp colonization. Sugar alcohols (mannitol, sorbitol, and xylitol) neither suppressed Rhizoctonia damping-off nor halted the saprotrophic growth of the pathogen. Seed germination was not affected by any of these six monosaccharides, whereas galactose and mannose inhibited seedling emergence significantly (P < 0.001) compared with the nontreated control or other monosaccharides. Soil fertilization with inorganic nitrogen at a C/N ratio of 20:1 negated the suppressive effects of glucose and fructose on both damping-off and saprotrophic colonization but improved seedling growth in carbonized soils. Obviously, microbial competition for mineral nitrogen was responsible for disease suppression; however, it delayed seedling growth after emergence. This paradox was resolved by adding glucose to the top 1-cm surface-soil zone at a C/N ratio of 50:1 or 125:1. This protected the laimosphere, resulting in effective disease suppression while complementarily enhancing seedling growth.


Assuntos
Beta vulgaris/microbiologia , Carbono/metabolismo , Monossacarídeos/metabolismo , Nitrogênio/metabolismo , Doenças das Plantas/microbiologia , Rhizoctonia/fisiologia , Solo/química , Antibacterianos/farmacologia , Recuperação e Remediação Ambiental/métodos , Frutose/metabolismo , Frutose/farmacologia , Glucose/metabolismo , Glucose/farmacologia , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Monossacarídeos/farmacologia , Doenças das Plantas/prevenção & controle , Plântula/microbiologia , Microbiologia do Solo , Xilose/metabolismo , Xilose/farmacologia
11.
Anatol J Cardiol ; 18(3): 206-212, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28777097

RESUMO

OBJECTIVE: The establishment of an optimal strategy for elderly patients with acute decompensated heart failure (ADHF) is currently an important issue. Particularly in very elderly (VE) patients, ADHF is associated with a poor prognosis. We therefore aimed to evaluate the efficacy and safety of the early use of tolvaptan (TLV) in VE patients. METHODS: Of 245 patients with ADHF admitted between March 2013 and July 2014, we prospectively enrolled 111 patients with TLV first administered within 24 h of hospitalization. These were divided into two groups according to the age: VE (≥85 years, n=45) and not very elderly (NVE, <85 years, n=66). The endpoints were the incidence of worsening renal function, death by any cause, or the length of hospital stay. RESULTS: There were no significant differences between the two groups in the incidence of worsening renal function (26.7% in VE vs. 25.8% in not VE, p=0.92), dose of TLV after hospitalization (7.4±0.7 vs. 7.5±1.3 mg/day, p=0.63), mean duration of the use of TLV (4.3±3.5 vs. 5.4±4.8 days, p=0.17), or mean length of hospital stay (16.5±7.8 vs. 15.7±8.0 days, p=0.64). CONCLUSION: TLV shows similar efficacy and safety in both VE and NVE groups. Even for VE patients with ADHF, initiation of TLV with standard diuretic treatment may have the potential not to increase the incidence of worsening renal function.


Assuntos
Antagonistas dos Receptores de Hormônios Antidiuréticos/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Tempo de Internação , Tolvaptan/uso terapêutico , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Antagonistas dos Receptores de Hormônios Antidiuréticos/administração & dosagem , Feminino , Serviços de Saúde para Idosos , Insuficiência Cardíaca/mortalidade , Humanos , Japão , Masculino , Estudos Prospectivos , Insuficiência Renal , Fatores de Risco , Análise de Sobrevida , Tolvaptan/administração & dosagem , Resultado do Tratamento
12.
J Cardiol ; 70(6): 511-517, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28780077

RESUMO

At present, there is consensus that prolonged dual antiplatelet therapy (DAPT) is effective to reduce cardiovascular events at the expense of bleeding complication events. A causal relationship of prolonged DAPT with an increase in mortality remains debatable, however, it appears to be obvious that bleeding complications are associated with an increase in cardiac events. Thus, individualized optimal DAPT duration balancing the risk and benefit of DAPT should be applied. In addition, strategy to minimize bleeding complications is highly recommended. Several risk scores have been reported to discriminate the risk and benefits of DAPT. However, in general, bleeding risk and event risk are correlated with each other, thus predictability of these scores is limited to moderate. Therefore, interpretation of previous trials is important to overcome the shortcome in outcomes. In this review, we provide an overview of DAPT trials and clarify the shortfalls to consider in Japan. Finally, possible future trends with reference to the results of recent clinical trials will be presented.


Assuntos
Stents Farmacológicos , Inibidores da Agregação Plaquetária/uso terapêutico , Hemorragia/induzido quimicamente , Hemorragia/prevenção & controle , Humanos , Japão , Inibidores da Agregação Plaquetária/efeitos adversos
14.
Braz. j. microbiol ; 42(2): 576-591, Apr.-June 2011. graf
Artigo em Inglês | LILACS | ID: lil-590005

RESUMO

Cells of Ralstonia solanacearum were exposed to Cu in distilled water, and the resulting Cu-stressed non-culturable cells were inoculated to natural (non-pasteurized) and pasteurized soils in order to examine their culturability and recovery. Exposing the cells to 20 µM CuSO4 produced transitory non-culturable cells, which exhibited a remarkable recovery in culturability after incubation in the solution for 36 h, reaching a density near the initial level by 108 h. To determine whether such non-culturable cells actually "resuscitated" or multiplied after adapting to Cu toxicity, growth curves were constructed in order to contrast the rates of increase in culturable cell numbers between Cu-stressed or non-stressed inocula. Additionally, fresh non-stressed cells were exposed to CuSO4 in the presence of nalidixic acid by adding the antibiotic at different times after the onset of Cu stress to verify any cell multiplication during the population increase. The results revealed that the non-culturable cells surviving Cu toxicity adapted very quickly to Cu and began multiplying within 12 h, because only the Cu-stressed cells that were increasing in the exponential growth phase, but not those in the stationary phase, were killed by the antibiotic. Such cells exhibited an apparent tolerance to this metal when inoculated to a freshly prepared solution of CuSO4, and also detoxified the ion in the solution in which they grew. The presence of nutrients greatly counteracted the effect of Cu in water microcosms, since culturable cells were detected and increased in number even when exposed to 40 µM CuSO4. In contrast, when inoculated to non-pasteurized soil, Cu-stressed cells showed no such recoveries. However, when the soil was pasteurized before inoculation or added with nutrients, culturable cells were recovered and increased in number. This indicates that increased nutrient availability in soil allows Cu-stressed cells to quickly overcome the stress and increase in culturable populations.

15.
Braz J Microbiol ; 42(2): 576-91, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24031670

RESUMO

Cells of Ralstonia solanacearum were exposed to Cu in distilled water, and the resulting Cu-stressed non-culturable cells were inoculated to natural (non-pasteurized) and pasteurized soils in order to examine their culturability and recovery. Exposing the cells to 20 µM CuSO4 produced transitory non-culturable cells, which exhibited a remarkable recovery in culturability after incubation in the solution for 36 h, reaching a density near the initial level by 108 h. To determine whether such non-culturable cells actually "resuscitated" or multiplied after adapting to Cu toxicity, growth curves were constructed in order to contrast the rates of increase in culturable cell numbers between Cu-stressed or non-stressed inocula. Additionally, fresh non-stressed cells were exposed to CuSO4 in the presence of nalidixic acid by adding the antibiotic at different times after the onset of Cu stress to verify any cell multiplication during the population increase. The results revealed that the non-culturable cells surviving Cu toxicity adapted very quickly to Cu and began multiplying within 12 h, because only the Cu-stressed cells that were increasing in the exponential growth phase, but not those in the stationary phase, were killed by the antibiotic. Such cells exhibited an apparent tolerance to this metal when inoculated to a freshly prepared solution of CuSO4, and also detoxified the ion in the solution in which they grew. The presence of nutrients greatly counteracted the effect of Cu in water microcosms, since culturable cells were detected and increased in number even when exposed to 40 µM CuSO4. In contrast, when inoculated to non-pasteurized soil, Cu-stressed cells showed no such recoveries. However, when the soil was pasteurized before inoculation or added with nutrients, culturable cells were recovered and increased in number. This indicates that increased nutrient availability in soil allows Cu-stressed cells to quickly overcome the stress and increase in culturable populations.

16.
Phytopathology ; 96(12): 1372-9, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18943670

RESUMO

ABSTRACT Suppressive effects of soil amendment with residues of 12 cultivars of Brassica rapa on damping-off of sugar beet were evaluated in soils infested with Rhizoctonia solani. Residues of clover and peanut were tested as noncruciferous controls. The incidence of damping-off was significantly and consistently suppressed in the soils amended with residues of clover, peanut, and B. rapa subsp. rapifera 'Saori', but only the volatile substance produced from water-imbibed residue of cv. Saori exhibited a distinct inhibitory effect on mycelial growth of R. solani. Nonetheless, disease suppression in such residue-amended soils was diminished or nullified when antibacterial antibiotics were applied to the soils, suggesting that proliferation of antagonistic bacteria resident to the soils were responsible for disease suppression. When the seed (pericarps) colonized by R. solani in the infested soil without residues were replanted into the soils amended with such residues, damping-off was suppressed in all cases. In contrast, when seed that had been colonized by microorganisms in the soils containing the residues were replanted into the infested soil, damping-off was not suppressed. The evidence indicates that the laimosphere, but not the spermosphere, is the site for the antagonistic microbial interaction, which is the chief principle of soil suppressiveness against Rhizoctonia damping-off.

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