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1.
Plant Dis ; 2022 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-35700520

RESUMO

Perilla (Perilla frutescens L.) is the second most important upland crop and the third largest edible oil crop in Korea (Shin and Kim 1994). During a disease survey in Busan, Korea in September 2021, symptoms of vein necrosis were observed in perilla plants, with incidences of approximately 30% and 50% in two fields. Symptoms of spots on the perilla appeared as leaf dryness and spots with water-soaked blotches largely concentrated on the mid-veins of leaves. The lesions were initiated with water-soaked spots on the leaf or stem and gradually turned black or brown. Necrosis was also observed in the stems. A bacterium was isolated on Luria-Bertani (LB) agar from diseased leaf tissues that were surface-disinfected with 70% ethyl alcohol for 3-5 min and then washed with sterile water three times. Three pieces of sterilized leaf tissue (size: 0.5 × 0.5 cm) were mixed with 500 µL sterile water for 30 min, and then the suspension was serially diluted and spread on LB agar. Subsequently, isolates were cultivated on LB agar and King's Medium B agar (KMB) (Schaad et al. 2001), and they were predominantly cream-colored and circular bacterial colonies with undulated margins. The bacterial colonies on KMB displayed fluorescence under 365 nm UV light. The isolates were analyzed with the GEN III MicroPlate (Biolog, Hayward, CA, USA), and all isolates were identified as Pseudomonas cichorii, a devastating plant bacterium that damages a wide range of host plants worldwide, including in South Korea (Hikichi et al. 2013; Ramkumar et al. 2015). To identify the species of the bacterial pathogen, genomic DNA of four isolates (BS4922, BS4167, BS4345, and BS4560) was extracted, and the 16S rRNA gene and hrcRST gene were amplified with universal primers, 27F/1492R and Hcr1/Hcr2, and sequencing was then done (Patel et al. 2019). In the BLAST analysis, the 16S rRNA sequences (GenBank OM060656, OM275434, OM275435, OM275436) showed a 100% and 99% similarity to P. cichorii strains MAFF 302698 (AB724286) and P. cichorii strain Pc-Gd-4 (KU923373), respectively. Further, hrcRST gene sequences (GenBank OM143596, OM268864, OM268865, and OM268866) showed high similarity (>99%) with P. cichorii strain P16-51 (MG518230). A pathogenicity test of the four isolates was performed on 3 - 4 weeks old perilla plants by creating wounds with a needle on the lower leaves and stems, and then the plants were inoculated by spraying inoculum (108 CFU/ml). The plants that served as the negative control were wounded and sprayed with unsterilized water. The inoculated perilla plants were placed in a greenhouse at 28 ± 2oC , 80-85% relative humidity, and a natural photoperiod. The inoculation site began to show symptoms of water-soaked brown lesions. Disease symptoms such as leaf dryness, water-soaked blotches on the mid-vein of leaves, and necrosis on plant stems were observed in the inoculated plants 7-10 days after inoculation, whereas the plants of the negative control group did not show any symptoms. The bacteria were re-isolated from the diseased tissues of the plants, and DNA sequence analysis identified them as P. cichorii. Additionally, all isolates induced hypersensitivity reactions in tobacco and tomato leaves within 24 h after inoculation. To our knowledge, this is the first report of P. cichorii infecting perilla in South Korea. The findings in this study will provide the basic information for the development of diagnostic tools and management measures against P. cichorii in perilla.

3.
AIDS Behav ; 23(11): 3078-3092, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31444711

RESUMO

Alcohol is the most widely abused substance in Namibia and is associated with poor adherence and retention in care among people on antiretroviral therapy (ART). Electronic screening and brief interventions (eSBI) are effective in reducing alcohol consumption in various contexts. We used a mixed methods approach to develop, implement, and evaluate the introduction of an eSBI in two ART clinics in Namibia. Of the 787 participants, 45% reported some alcohol use in the past 12 months and 25% reported hazardous drinking levels. Hazardous drinkers were more likely to be male, separated/widowed/divorced, have a monthly household income > $1000 NAD, and report less than excellent ART adherence. Based on qualitative feedback from participants and providers, ART patients using the eSBI for the first time found it to be a positive and beneficial experience. However, we identified several programmatic considerations that could improve the experience and yield in future implementation studies.


Assuntos
Consumo de Bebidas Alcoólicas/prevenção & controle , Consumo de Bebidas Alcoólicas/psicologia , Antirretrovirais/uso terapêutico , Aconselhamento , Infecções por HIV/tratamento farmacológico , Adulto , Consumo de Bebidas Alcoólicas/efeitos adversos , Feminino , Grupos Focais , Infecções por HIV/psicologia , Humanos , Entrevistas como Assunto , Masculino , Programas de Rastreamento , Namíbia , Pesquisa Qualitativa
4.
Transplant Proc ; 50(10): 3984-3987, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30577301

RESUMO

Brain death is a rare situation after living-donor liver transplantation. However, the recipient who suffers from brain death and has functional liver graft is a potential liver donor. We report the 1st case of successful reuse of extended right living-donor liver graft after brain death of the first recipient. The first recipient, who had acute liver failure caused by hepatitis A virus, experienced brain death on the 2nd day after the transplantation. The allograft had a favorable regeneration and functional recovery. On the 7th day, the allograft was procured with a patent hepatic artery, bile duct, portal vein, and reconstructed outflow (right hepatic vein and middle hepatic vein) and successfully implanted into the second recipient. The second recipient has experienced a long-term survival without any complications.


Assuntos
Transplante de Fígado/mortalidade , Transplante de Fígado/métodos , Doadores Vivos/provisão & distribuição , Obtenção de Tecidos e Órgãos/métodos , Adulto , Morte Encefálica , Feminino , Humanos , Masculino , Resultado do Tratamento
5.
Hum Exp Toxicol ; 37(4): 331-337, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28421825

RESUMO

The incidence and clinical aspects of seizures remain to be elucidated in patients with acute pesticide intoxication. The present study included subjects who ingested pesticide with the intention of committing suicide and were treated at Soonchunhyang University Hospital (Cheonan, Korea) between January 2011 and December 2014. We analyzed the incidence and characterized the type and frequency of seizure, from the medical records of 464 patients with acute pesticide intoxication, according to the pesticide class. The effect of seizure on the clinical outcome was assessed. The incidence of seizure was 31.5% in patients who ingested glufosinate ammonium {2-amino-4-[hydroxyl (methyl) phosphinoyl] butyrate; ammonium DL-homoalanin-4-yl (methyl) phosphinate}, followed by those who ingested pyrethroid (5.9%) or glycine derivatives (5.4%). All of the seizures developed between 12 and 24 h of pesticide ingestion and had ceased by 72 h after seizure initiation, following treatment with antiseizure medication. Generalized tonic-clonic seizures were the most commonly observed (85.7% of the cases). Multivariable logistic regression analysis showed that the effect of seizure on mortality was not statistically significant. In conclusion, glufosinate ammonium herbicide is the most common seizurogenic pesticide class. Seizure itself was not a risk factor for mortality in patients with acute glufosinate ammonium intoxication.


Assuntos
Aminobutiratos/intoxicação , Herbicidas/intoxicação , Síndromes Neurotóxicas/etiologia , Convulsões/induzido quimicamente , Tentativa de Suicídio , Adulto , Idoso , Anticonvulsivantes/uso terapêutico , Distribuição de Qui-Quadrado , Feminino , Glicina/análogos & derivados , Glicina/intoxicação , Hospitais Universitários , Humanos , Incidência , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Síndromes Neurotóxicas/diagnóstico , Síndromes Neurotóxicas/tratamento farmacológico , Síndromes Neurotóxicas/mortalidade , Piretrinas/intoxicação , República da Coreia , Fatores de Risco , Convulsões/diagnóstico , Convulsões/tratamento farmacológico , Convulsões/mortalidade , Fatores de Tempo , Resultado do Tratamento
6.
Transplant Proc ; 49(10): 2395-2398, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29198688

RESUMO

INTRODUCTION: Although outcomes of liver transplantation (LT) have improved as the result of progress in surgical procedures, a failure to restore sufficient graft outflow may yield fatal consequences including graft dysfunction and even graft loss to date. In particular, patients with pre-existing obliterated venous drainage, such as those with Budd-Chiari syndrome (BCS), are at high risk of having venous complications followed by conventional LT. In selected cases, the transplant surgeons are compelled to modify the surgical procedures of LT from the conventional procedure. METHODS: We describe an LT performed in a BCS patient with complete inferior vena cava (IVC) obstruction. A procedure that we named "hanging hepato-atrial anastomosis" was performed, in which 2 major modifications were made. One modification was the dissection of the lower inlet of the right atrium by use of a trans-abdominal approach and hepato-atrial anastomosis. This was performed by exposing the thoracic IVC through a trans-abdominal approach. The other modification was the manufacture of a blind pouch from the graft's infra-hepatic IVC without anastomosis. RESULTS: Modifications were made possible as the result of meticulous examination of the patient's vascular anatomy before the operation. Fortunately, the patient had a heavy network of pre-vertebral veins that drained blood from the lower extremity and both kidneys to the azygos-hemi-azygos veins. CONCLUSIONS: We learned that a meticulous assessment of vascular anatomy and complete understanding of hemodynamics are the keys to the successful LT for BCS in patients with extensive IVC abnormality. Thoracotomy may not be necessary to explore thoracic IVC when performing hepato-atrial anastomosis in LT for BCS.


Assuntos
Síndrome de Budd-Chiari/cirurgia , Transplante de Fígado/métodos , Anastomose Cirúrgica/métodos , Veias Hepáticas/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Veia Cava Inferior/cirurgia
7.
Folia Morphol (Warsz) ; 75(4): 560-564, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27830894

RESUMO

We herein report a case showing three anatomical variations including the aberrant right subclavian artery (ARSA), the non-recurrent laryngeal nerve (NRLN) and the right thoracic duct in a 59-year-old male cadaver. The right subclavian artery (RSA) arose from the descending aorta next to the left subclavian artery and coursed in between the oesophagus and the thoracic vertebrae. The recurrent laryngeal nerve did not coil around the RSA but directly entered the larynx. Lastly the thoracic duct terminated into the right brachiocephalic vein. This study makes an embryological assumption that the abnormal development of the RSA had happened first and subsequently caused NRLN and the thoracic duct drainage variation. As to our knowledge, only two reports have been made previously concerning such concurrent variations. Therefore, this case report alerts anatomists and clinicians to the possibility of simultaneous occurrence of ARSA, NRLN and the right thoracic duct.


Assuntos
Aneurisma , Anormalidades Cardiovasculares , Artéria Subclávia/anormalidades , Aorta Torácica , Humanos , Masculino , Pessoa de Meia-Idade , Nervo Laríngeo Recorrente , Ducto Torácico
8.
Hum Exp Toxicol ; 34(8): 848-55, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25398874

RESUMO

OBJECTIVE: Self-poisoning with (4-chloro-2-methylphenoxy) acetic acid (MCPA) is a common reason for presentation to hospitals, especially in some Asian countries. We encountered a case of a 76-year-old woman who experienced unconsciousness, shock and respiratory failure after ingesting 100 mL MCPA herbicide. We determined whether the surfactant in the formulation was the chemical responsible for the toxic symptom in this patient. DESIGN: 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability and lactate dehydrogenase (LDH) cytotoxicity assays were performed on human brain neuroblastoma SK-N-SH cells. The expressions of 84 genes in 9 categories that are implicated in cellular damage pathways were quantified using an RT(2) Profiler™ PCR array on a human neuronal cell line challenged with polyoxyethylene tridecyl ether (PTE). SETTING: Pesticide intoxication institute in university hospital. INTERVENTIONS: Extracorporeal elimination with intravenous lipid emulsion. MEASUREMENTS: Cell viability and gene expression. MAIN RESULTS: In the MTT assay, MCPA only minimally decreased cell viability even at concentrations as high as 1 mM. Cells treated with 1-methoxy-2-propanol, dimethylamine and polypropylene glycol exhibited minimal decreases in viability, whilst the viability of cells challenged with PTE decreased dramatically; only 15.5% of cells survived after exposure to 1 µM PTE. Similarly, the results of the LDH cytotoxicity assay showed that MCPA had very low cytotoxicity, whilst cells treated with PTE showed incomparably higher LDH levels (p < 0.0001). PTE up-regulated the expressions of genes implicated in various cell damage pathways, particularly genes involved in the inflammatory pathway. CONCLUSIONS: The surfactant PTE was likely the chemical responsible for the toxic symptom in our patient.


Assuntos
Ácido 2-Metil-4-clorofenoxiacético/toxicidade , Herbicidas/toxicidade , Tensoativos/toxicidade , Idoso , Linhagem Celular Tumoral , Feminino , Humanos
9.
Int J STD AIDS ; 25(9): 662-668, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24352130

RESUMO

The HIV epidemic in Vietnam is concentrated, with high prevalence estimates among injection drug users and commercial sex workers. Socio-demographics, substance use and clinical correlates of antiretroviral therapy non-adherence were studied in 100 HIV-1 infected drug users receiving antiretroviral therapy for at least 6 months in Hanoi, Vietnam. All study participants were men with a mean age of 29.9 ± 4.9 years. The median duration on antiretroviral therapy was 16.2 ± 12.7 months; 83% reported 'very good' or 'perfect' adherence in the past 30 days on a subjective one-item Likert scale at time of study enrollment; 48% of participants reported drug use within the previous 6 months, with 22% reporting current drug use. Injection drug use with or without non-injection drug use in the past 6 months (95% C.I. 2.19, 1.30-3.69) and years on antiretroviral therapy (95% C.I. 1.43, 1.14-1.78) were correlated with suboptimal adherence. These findings support Vietnam's ongoing scale-up of harm reduction programmes for injection drug users and their integration with antiretroviral therapy delivery. Moreover, results highlight the need to identify and implement new ways to support high levels of antiretroviral therapy adherence as duration on antiretroviral therapy increases.


Assuntos
Terapia Antirretroviral de Alta Atividade , Usuários de Drogas/estatística & dados numéricos , Infecções por HIV/tratamento farmacológico , Adesão à Medicação , Abuso de Substâncias por Via Intravenosa/complicações , Adulto , Antirretrovirais/uso terapêutico , Estudos de Coortes , Feminino , Infecções por HIV/epidemiologia , Infecções por HIV/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Fatores Socioeconômicos , Abuso de Substâncias por Via Intravenosa/epidemiologia , Resultado do Tratamento , Vietnã/epidemiologia , Carga Viral , Adulto Jovem
10.
Hum Exp Toxicol ; 31(12): 1299-302, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23023026

RESUMO

When clinicians treat patients with pesticide poisoning, they often pay attention only to the chief toxic agent and ignore the toxicity of the pesticide's additives or solvents. Occasionally, however, a solvent (e.g. methanol) may itself be the cause of poisoning. We report a case of acute methanol intoxication that occurred after ingestion of a methomyl pesticide that contained methanol as an additive. A 49-year-old man was brought to the emergency department in an unconscious state after ingestion of 20 ml of a carbamate pesticide (chief ingredient: methomyl; active ingredient: methanol). Upon arrival, he was semicomatose and did not breathe spontaneously; however, his cholinesterase level was within normal limits and cholinergic symptoms were not observed. High anion gap metabolic acidosis was present. His blood ethanol level was 74.8 mg/dL. The urine methanol level was 55.60 mg/dL, and urine ethanol level was 22.0 mg/dL. He was treated with hemodialysis; subsequently, his metabolic acidosis resolved and he returned to normal mental status. We guessed that methanol, as the solvent of the methomyl, had produced the symptoms. When treating pesticide-poisoned patients, clinicians should identify the solvent used in the pesticide, because solvents such as methanol may exacerbate the symptoms of poisoned patients.


Assuntos
Intoxicação Alcoólica/etiologia , Inseticidas/toxicidade , Metanol/efeitos adversos , Metomil/toxicidade , Solventes/efeitos adversos , Acidose/diagnóstico , Acidose/etiologia , Acidose/terapia , Intoxicação Alcoólica/diagnóstico , Intoxicação Alcoólica/terapia , Combinação de Medicamentos , Humanos , Masculino , Pessoa de Meia-Idade , Diálise Renal
11.
Clin Infect Dis ; 54 Suppl 4: S245-9, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22544182

RESUMO

The HIV drug resistance (HIVDR) prevention and assessment strategy, developed by the World Health Organization (WHO) in partnership with HIVResNet, includes monitoring of HIVDR early warning indicators, surveys to assess acquired and transmitted HIVDR, and development of an accredited HIVDR genotyping laboratory network to support survey implementation in resource-limited settings. As of June 2011, 52 countries had implemented at least 1 element of the strategy, and 27 laboratories had been accredited. As access to antiretrovirals expands under the WHO/Joint United Nations Programme on HIV/AIDS Treatment 2.0 initiative, it is essential to strengthen HIVDR surveillance efforts in the face of increasing concern about HIVDR emergence and transmission.


Assuntos
Antirretrovirais/farmacologia , Infecções por HIV/tratamento farmacológico , Política de Saúde , Países em Desenvolvimento , Farmacorresistência Viral , Saúde Global , Inquéritos Epidemiológicos , Humanos , Organização Mundial da Saúde
12.
J Appl Microbiol ; 113(1): 52-65, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22519412

RESUMO

AIMS: Isoprene (2-methyl-1,3-butadiene; C(5) H(8) ) is naturally produced by photosynthesis and emitted in the atmosphere by the leaves of many herbaceous, deciduous and woody plants. Fermentative yeast and fungi (Ascomycota) are not genetically endowed with the isoprene production process. The work investigated whether Ascomycota can be genetically modified and endowed with the property of constitutive isoprene production. METHODS AND RESULTS: Two different strategies for expression of the IspS gene in Saccharomyces cerevisiae were employed: (i) optimization of codon usage of the IspS gene for specific expression in S. cerevisiae and (ii) multiple independent integrations of the IspS gene in the rDNA loci of the yeast genome. Copy number analysis showed that IspS transgenes were on the average incorporated within about 25% of the endogenous rDNA. Codon use optimization of the Pueraria montana (kudzu vine) IspS gene (SckIspS) for S. cerevisiae showed fivefold greater expression of the IspS protein compared with that of nonoptimized IspS (kIspS). With the strategies mentioned earlier, heterologous expression of the kudzu isoprene synthase gene (kIspS) in S. cerevisiae was tested for stability and as a potential platform of fermentative isoprene production. The multi-copy IspS transgenes were stably integrated and expressed for over 100 generations of yeast cell growth and constitutively produced volatile isoprene hydrocarbons. Secondary chemical modification of isoprene to a number of hydroxylated isoprene derivatives in the sealed reactor was also observed. CONCLUSION: Transformation of S. cerevisiae with the Pueraria montana var. lobata (kudzu vine) isoprene synthase gene (IspS) conferred to the yeast cells constitutive isoprene hydrocarbons production in the absence of adverse or toxic effects. SIGNIFICANCE AND IMPACT OF THE STUDY: First-time demonstration of constitutive isoprene hydrocarbons production in a fermentative eukaryote operated through the mevalonic acid pathway. The work provides concept validation for the utilization of S. cerevisiae, as a platform for the production of volatile hydrocarbon biofuels and chemicals.


Assuntos
Alquil e Aril Transferases/genética , Engenharia Genética , Hemiterpenos/biossíntese , Saccharomyces cerevisiae/metabolismo , Butadienos , Códon , DNA Ribossômico/genética , Fermentação , Pentanos , Plasmídeos , Pueraria/enzimologia , Pueraria/genética , Saccharomyces cerevisiae/genética , Transformação Genética , Transgenes
13.
Acta Virol ; 53(1): 7-13, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19301945

RESUMO

Hemorrhagic fever with renal syndrome (HFRS) caused by Hantaan virus (HTNV) is characterized by vascular hemorrhage and acute renal failure. Angiopoietin-1 (Ang-1) is a glycoprotein that maintains vessel integrity and reduces endothelial permeability. We found that in HTNV-infected human umbilical vein endothelial cells (HUVECs) the levels of Ang-1 mRNA and protein were reduced on days 2 and 3 post-infection (p.i.), when endothelial permeability was increased. The HTNV-stimulated permeability was reduced by treatment of HUVECs with Ang-1. The plasma Ang-1 level was lower in HFRS patients than in healthy persons. Paired plasma samples of HFRS patients revealed markedly lower Ang-1 levels during the acute phase of HFRS as compared to the convalescent phase. These findings suggested that HTNV reduced the Ang-1 expression in endothelial cells that might play an important role in the increase of vascular permeability in HFRS.


Assuntos
Angiopoietina-1/antagonistas & inibidores , Angiopoietina-1/biossíntese , Permeabilidade Capilar , Células Endoteliais/virologia , Vírus Hantaan/fisiologia , Angiopoietina-1/sangue , Células Cultivadas , Perfilação da Expressão Gênica , Humanos , Plasma/química , Veias Umbilicais/citologia
15.
J Phys Chem B ; 110(50): 25399-410, 2006 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-17165987

RESUMO

MoS2 nanooctahedra are believed to be the smallest stable closed-cage structures of MoS2, i.e., the genuine inorganic fullerenes. Here a combination of experiments and density functional tight binding calculations with molecular dynamics annealing are used to elucidate the structures and electronic properties of octahedral MoS2 fullerenes. Through the use of these calculations MoS2 octahedra were found to be stable beyond nMo > 100 but with the loss of 12 sulfur atoms in the six corners. In contrast to bulk and nanotubular MoS2, which are semiconductors, the Fermi level of the nanooctahedra is situated within the band, thus making them metallic-like. A model is used for extending the calculations to much larger sizes. These model calculations show that, in agreement with experiment, the multiwall nanooctahedra are stable over a limited size range of 104-105 atoms, whereupon they are converted into multiwall MoS2 nanoparticles with a quasi-spherical shape. On the experimental side, targets of MoS2 and MoSe2 were laser-ablated and analyzed mostly through transmission electron microscopy. This analysis shows that, in qualitative agreement with the theoretical analysis, multilayer nanooctahedra of MoS2 with 1000-25 000 atoms (Mo + S) are stable. Furthermore, this and previous work show that beyond approximately 105 atoms fullerene-like structures with quasi-spherical forms and 30-100 layers become stable. Laser-ablated WS2 samples yielded much less faceted and sometimes spherically symmetric nanocages.


Assuntos
Dissulfetos/química , Fulerenos/química , Molibdênio/química , Simulação por Computador , Dissulfetos/síntese química , Modelos Moleculares , Estrutura Molecular , Tamanho da Partícula
16.
Eur J Cancer Prev ; 14(2): 175-9, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15785322

RESUMO

It is still unclear whether the exposure to electromagnetic fields (EMFs) generated by mobile phone radiation is directly linked to cancer. We examined the biological effects of an EMF at 835 MHz, the most widely used communication frequency band in Korean CDMA mobile phone networks, on bacterial reverse mutation (Ames assay) and DNA stability (in vitro DNA degradation). In the Ames assay, tester strains alone or combined with positive mutagen were applied in an artificial mobile phone frequency EMF generator with continuous waveform at a specific absorption rate (SAR) of 4 W/kg for 48 h. In the presence of the 835-MHz EMF radiation, incubation with positive mutagen 4-nitroquinoline-1-oxide and cumene hydroxide further increased the mutation rate in Escherichia coli WP2 and TA102, respectively, while the contrary results in Salmonella typhimurium TA98 and TA1535 treated with 4-nitroquinoline-1-oxide and sodium azide, respectively, were shown as antimutagenic. However, these mutagenic or co-mutagenic effects of 835-MHz radiation were not significantly repeated in other relevant strains with same mutation type. In the DNA degradation test, the exposure to 835-MHz EMF did not change the rate of degradation observed using plasmid pBluescript SK(+) as an indicator. Thus, we suggest that 835-MHz EMF under the conditions of our study neither affected the reverse mutation frequency nor accelerated DNA degradation in vitro.


Assuntos
Telefone Celular , Dano ao DNA , Campos Eletromagnéticos/efeitos adversos , 4-Nitroquinolina-1-Óxido/toxicidade , Derivados de Benzeno/toxicidade , DNA Bacteriano , Escherichia coli/genética , Testes de Mutagenicidade , Mutagênicos/toxicidade , Mutação , Plasmídeos , Salmonella typhimurium/genética , Azida Sódica/toxicidade
17.
Water Sci Technol ; 50(9): 91-7, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15580999

RESUMO

Ultrasound treatment of primary and secondary sludges was conducted to improve the qualities of sludges for the anaerobic digestion. The impacts of different sonication times, sonication densities and solids concentrations on ultrasonication efficiency were examined. The experimental results indicated that the significant reduction in particle size and increase in soluble organics could be achieved, implying that ultrasonication could offer a feasible treatment method to efficiently disintegrate sludge. The greater decrease in particle size and increase in soluble organics of sludge indicated that the secondary sludge has a more remarkable improvement after sonication over the primary sludge. With respects to the extent of disintegration and energy consumption, higher sonication density performed more effectively in terms of specific energy. There exists an optimal solids concentration range for both the sludges for optimum sonication. Within the optimal solids concentration range, efficient sonication can be effected and sludge would be disintegrated efficiently. The ultrasound would be attenuated by scattering and absorption if the solids concentration exceeds the optimal range. It appeared from the study that the mechanical shear forces caused by ultrasonic cavitation could be a key factor for sludge disintegration and collapse of cavitation bubbles could significantly alter the sludge characteristics.


Assuntos
Esgotos/química , Sonicação , Gerenciamento de Resíduos , Tamanho da Partícula , Singapura , Solubilidade , Gerenciamento de Resíduos/métodos
18.
Water Sci Technol ; 50(9): 189-96, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15581012

RESUMO

The disposal of sludge from wastewater treatment presents highly complex problems to any municipality. Most of the sludge disposal methods have varying degrees of environmental impact. Hence, it is necessary to explore potential areas of reuse in order to alleviate sludge disposal problems and to conserve natural resources. Industrial sludge and marine clay are two forms of high-volume wastes. Using these wastes as a resource of raw materials to produce construction aggregates would enable large-scale sludge reuse. The aggregates were produced at various sludge-clay combinations containing 0, 20, 50, 80 and 100% clay contents, respectively. The pelletized aggregates displayed lower particle densities ranged between 1.48 and 2.25 g/cm3, compared to the density of granite at 2.56 g/cm3. Good 28-day concrete compressive strength of 38.5 N/mm2 achieved by the 100% sludge aggregate was comparable to the value of 38.0 N/mm2 achieved of the granite control specimens. The leachate contamination levels from the aggregates after 150 days were found acceptable when used in concrete, indicating insignificant environmental contamination. The heat flow study showed increases in heat flow at the temperatures of 480 degrees C and between 660 degrees C and 900 degrees C, indicating a need for the extension of heating time around these temperatures.


Assuntos
Silicatos de Alumínio/química , Conservação dos Recursos Naturais , Materiais de Construção , Sedimentos Geológicos/química , Esgotos/química , Silicatos de Alumínio/análise , Argila , Força Compressiva , Materiais de Construção/análise , Materiais de Construção/normas , Cobre , Resíduos Industriais , Esgotos/análise , Navios
19.
J Appl Microbiol ; 97(2): 378-83, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15239705

RESUMO

AIMS: To examine the diversity of protozoa in the rumen contents of cow. METHODS AND RESULTS: Protozoa that inhabit the rumen were detected by PCR using protozoan-specific primers. Libraries of protozoan rDNA sequences were constructed from rumen fluid, solid tissues and epithelium. Twenty-three clones isolated from rumen fluid fell into two genera identified as Entodinium (69.6% of clones) and Epidinium (31.4% of clones). Of the clones isolated from rumen fluid, a moderate number were unidentifiable (30.4%). CONCLUSIONS: The predominant protozoan genus identified in the whole rumen belonged to the Entodinium group (81.1%). Protozoa were not detected in the rumen epithelium. SIGNIFICANCE AND IMPACT OF THE STUDY: These findings suggest that rumen fluid and solid tissues contain different protozoan populations that may play specific roles in rumen function. Quantitative PCR techniques and a more specific set of phylogenetic probes that distinguish between protozoan species are needed to determine the significance of newly identified groups and to determine the distribution of identified protozoan clusters in rumen microbial communities.


Assuntos
DNA de Protozoário/genética , DNA Ribossômico/genética , Eucariotos/genética , Filogenia , Rúmen/parasitologia , Animais , Sequência de Bases , Bovinos , Clonagem Molecular/métodos , Variação Genética/genética
20.
Lett Appl Microbiol ; 38(4): 296-300, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15214728

RESUMO

AIMS: To isolate the cellulase gene from Rhizobium leguminosarum bv. trifolii 1536. METHODS AND RESULTS: By the shot-gun method a clone (cel8A) harbouring 3.1 kb genomic DNA fragment from R. leguminosarum bv. trifolii 1536 was obtained. The cel8A gene coded 348 amino acids and it belongs to the glycosyl hydrolase family 8. The molecular mass of Cel8A protein induced from Escherichia coli DH5alpha, appeared to be 35 kDa. The optimum pH and optimum temperature was 7.0, and about 30 degrees C for its enzymatic activity respectively. CONCLUSIONS: R. leguminosarum bv. trifolii 1536 had cel8A gene having an open reading frame of 1047 bp coded for the activity of hydrolyzation of carboxymethyl cellulose. SIGNIFICANCE AND IMPACT OF THE STUDY: The production of celluloytic enzyme by R. leguminosarum bv. trifolii was confirmed, which would play specific roles in rhizobia. Future study should focus on its role in the infection and nodulation phenomena.


Assuntos
Celulase/genética , Celulase/metabolismo , Rhizobium leguminosarum/enzimologia , Rhizobium leguminosarum/genética , Celulase/química , Clonagem Molecular , DNA Bacteriano/química , DNA Bacteriano/isolamento & purificação , Estabilidade Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Genes Bacterianos , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Peso Molecular , Fases de Leitura Aberta , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Temperatura
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