scholarly journals Atividade antibacteriana do óleo essencial do manjericão frente a sorogrupos de Escherichia coli enteropatogênica isolados de alfaces

2010 ◽  
Vol 40 (8) ◽  
pp. 1791-1796 ◽  
Author(s):  
André Gustavo Lima de Almeida Martins ◽  
Adenilde Ribeiro Nascimento ◽  
João Elias Mouchrek Filho ◽  
Nestor Everton Mendes Filho ◽  
Antonio Gouveia Souza ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lactuca Sativa ◽  
Ocimum Basilicum ◽  
E Coli

Considerando-se a crescente participação dos vegetais na transmissão de microrganismos, incluindo as Escherichia coli enteropatogênicas multirresistentes às drogas convencionais, a busca por novos compostos com propriedades antimicrobianas a partir de fontes naturais, tais como os óleos essenciais, tem se intensificado nos últimos anos. Esta pesquisa objetivou avaliar a atividade antibacteriana do óleo essencial do manjericão (Ocimum basilicum Linn.) frente a sorogrupos de Escherichia coli enteropatogênicas (EPEC) isolados de alfaces (Lactuca sativa), utilizando-se o Método de Difusão em Disco (MDD). Os resultados evidenciaram que todas as cepas de E. coli EPEC testadas apresentaram sensibilidade à ação do óleo essencial, sugerindo que este possa ser uma fonte de compostos com potencial terapêutico no combate a bactérias patogênicas.

scholarly journals Atividade antimicrobiana de óleos essenciais em bactérias patogênicas de origem alimentar

2012 ◽  
Vol 14 (1) ◽  
pp. 57-67 ◽  
Author(s):  
C. Valeriano ◽  
R.H. Piccoli ◽  
M.G. Cardoso ◽  
E. Alves
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Salmonella Enterica ◽  
Ocimum Basilicum ◽  
Mentha Piperita ◽  
Enterobacter Sakazakii ◽  
Cymbopogon Citratus ◽  
E Coli ◽  
Origanum Majorana

Objetivou-se identificar e quantificar os constituintes e avaliar a atividade antimicrobiana dos óleos essenciais de Mentha piperita, Cymbopogon citratus, Ocimum basilicum e Origanum majorana contra cepas de Escherichia coli enteropatogênica, Salmonella enterica Enteritidis, Listeria monocytogenes e Enterobacter sakazaki. A obtenção dos óleos essenciais foi realizada a partir de folhas secas, empregando-se a técnica de hidrodestilação e utilizando-se a aparelho de Clevenger modificado. A atividade antibacteriana dos óleos essenciais foi determinada pelo método de difusão em ágar. Observou-se que os óleos essenciais inibiram o crescimento bacteriano, mas a efetividade foi variada. Entre os óleos essenciais testados, M. piperita apresentou maior atividade antibacteriana para E. coli, (8.106 UA mL-1) quando comparada as demais bactérias, atividade moderada para Salmonella enterica Enteritidis e Enterobacter sakazakii (1.706 e 3.200 UA mL-1 respectivamente) e baixa atividade para Listeria monocytogenes (106,67 UA mL-1). Já óleo essencial de Cymbopogon citratus apresentou maior atividade antimicrobiana frente a E. coli (9.386 UA mL-1) e atividade moderada frente a Enterobacter sakazakii, Salmonella enterica Enteritidis e Listeria monocytogenes (2.773 UA mL-1 para ambas). Ocimum basilicum apresentou maior atividade antibacteriana frente E. coli e Enterobacter sakazakii (6.826 e 8.106 UA mL-1 respectivamente), moderada atividade frente a Salmonella enterica Enteritidis (1.600 UA mL-1) e não apresentou atividade frente a Listeria monocytogenes.Origanum majorana também foi testado neste estudo e apresentou maior atividade antimicrobiana frente E. coli (5.973 UA mL-1), atividade moderada para Salmonella enterica Enteritidis e Enterobacter sakazakii (1.706 e 2.346 UA mL-1 , respectivamente) e não apresentou atividade para Listeria monocytogenes.

scholarly journals Avaliação bacteriológica e físico-química de águas de irrigação, solo e alface (Lactuca sativa L.)

2016 ◽  
Vol 11 (3) ◽  
pp. 665
Author(s):  
Karine Scherer ◽  
Camille Eichelberger Granada ◽  
Simone Stülp ◽  
Raul Antonio Sperotto
Keyword(s):  
Escherichia Coli ◽  
Lactuca Sativa ◽  
Rio Grande ◽  
Rio Grande Do Sul ◽  
E Coli ◽  
Lactuca Sativa L ◽  
De Se

A contaminação de hortaliças por micro-organismos patogênicos está diretamente relacionada com a qualidade das águas de irrigação utilizadas na agricultura e com o solo onde se encontram. Com o objetivo de se verificar as condições empregadas na produção de alface (Lactuca sativa L.) em três pequenas propriedades do interior do Rio Grande do Sul (Brasil), foram avaliadas a condição físico-química das águas de irrigação, e a condição microbiológica das águas, solo e folhas de alface. As análises bacteriológicas das águas de irrigação, hortaliças e do solo foram realizadas usando a técnica dos tubos múltiplos ou por contagem em placa, e levou em conta os coliformes totais, coliformes termotolerantes, e presença ou ausência de Escherichia coli, Salmonella sp. e Listeria sp.. As análises físico químicas realizadas nas águas de irrigação foram pH, turbidez, oxigênio dissolvido, demanda bioquímica de oxigênio, carbono orgânico total e nitrogênio total. As análises bacteriológicas nas águas de irrigação indicaram a ausência de Salmonella sp. e Listeria sp.. Entretanto, foi detectada a presença de E. coli e valores acima do permitido pela legislação para coliformes termotolerantes. Desta forma, estas águas se encontram fora dos padrões estabelecidos pela Resolução CONAMA n° 357. A pesquisa também mostrou a presença de E. coli, Salmonella sp. e Listeria sp. nas hortaliças irrigadas, sugerindo que a fonte de contaminação por Salmonella sp. e Listeria sp. deve ser a partir do solo, e não a partir da água de irrigação. Os dados físico-químicos mostraram que apenas uma das propriedades analisadas apresentou todos os parâmetros adequados, segundo a legislação vigente para águas doces de classe 1. Portanto, apenas uma das propriedades apresentou condições físico químicas para ser utilizada na irrigação de alface, embora nenhuma tenha apresentado condições higiênico-sanitárias para tal uso.

scholarly journals Persistence of Escherichia coli in the microbiomes of red Romaine lettuce (Lactuca sativa cv. ‘Outredgeous’) and mizuna mustard (Brassica rapa var. japonica) - does seed sanitization matter?

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Anirudha R. Dixit ◽  
Christina L. M. Khodadad ◽  
Mary E. Hummerick ◽  
Cory J. Spern ◽  
LaShelle E. Spencer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
16S Rrna ◽  
Brassica Rapa ◽  
Lactuca Sativa ◽  
Leaf Tissue ◽  
16S Rrna Sequencing ◽  
Romaine Lettuce ◽  
E Coli ◽  
Rrna Sequencing ◽  
The Impact

Abstract Background Seed sanitization via chemical processes removes/reduces microbes from the external surfaces of the seed and thereby could have an impact on the plants’ health or productivity. To determine the impact of seed sanitization on the plants’ microbiome and pathogen persistence, sanitized and unsanitized seeds from two leafy green crops, red Romaine lettuce (Lactuca sativa cv. ‘Outredgeous’) and mizuna mustard (Brassica rapa var. japonica) were exposed to Escherichia coli and grown in controlled environment growth chambers simulating environmental conditions aboard the International Space Station. Plants were harvested at four intervals from 7 days post-germination to maturity. The bacterial communities of leaf and root were investigated using the 16S rRNA sequencing while quantitative polymerase chain reaction (qPCR) and heterotrophic plate counts were used to reveal the persistence of E. coli. Result E. coli was detectable for longer periods of time in plants from sanitized versus unsanitized seeds and was identified in root tissue more frequently than in leaf tissue. 16S rRNA sequencing showed dynamic changes in the abundance of members of the phylum Proteobacteria, Firmicutes, and Bacteroidetes in leaf and root samples of both leafy crops. We observed minimal changes in the microbial diversity of lettuce or mizuna leaf tissue with time or between sanitized and unsanitized seeds. Beta-diversity showed that time had more of an influence on all samples versus the E. coli treatment. Conclusion Our results indicated that the seed surface sanitization, a current requirement for sending seeds to space, could influence the microbiome. Insight into the changes in the crop microbiomes could lead to healthier plants and safer food supplementation.

Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

1967 ◽  
Vol 25 ◽  
pp. 96-97
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Electron Microscope ◽  
Uranyl Acetate ◽  
E Coli ◽  
Receptor Sites ◽  
Rigid Cell Wall ◽  
Host Cell Surface ◽  
Bacterial Viruses ◽  
Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

The Influence of Glycosylation on the Catalytic and Fibrinolytic Properties of Pro-Urokinase

1992 ◽  
Vol 68 (05) ◽  
pp. 539-544 ◽  
Author(s):  
Catherine Lenich ◽  
Ralph Pannell ◽  
Jack Henkin ◽  
Victor Gurewich
Keyword(s):  
Escherichia Coli ◽  
Mammalian Cell ◽  
Human Gene ◽  
Culture Media ◽  
Mammalian Cell Culture ◽  
Glycosylation Site ◽  
Clot Lysis ◽  
Cell Culture Media ◽  
E Coli ◽  
The Uk

SummaryWe previously found that human pro-UK expressed in Escherichia coli is more active in fibrinolysis than recombinant human pro-UK obtained from mammalian cell culture media. To determine whether this difference is related to the lack of glycosylation of the E. coli product, we compared the activity of E. coli-derived pro-UK [(-)pro-UK] with that of a glycosylated pro-UK [(+)pro-UK] and of a mutant of pro-UK missing the glycosylation site at Asn-302 [(-) (302) pro-UK]. The latter two pro-UKs were obtained by expression of the human gene in a mammalian cell. The nonglycosylated pro-UKs were activated by plasmin more efficiently (≈2-fold) and were more active in clot lysis (1.5-fold) than the (+)pro-UK. Similarly, the nonglycosylated two-chain derivatives (UKs) were more active against plasminogen and were more rapidly inactivated by plasma inhibitors than the (+)UK.These findings indicate that glycosylation at Asn-302 influences the activity of pro-UK/UK and could be the major factor responsible for the enhanced activity of E. coli-derived pro-UK.

Usefulness of a Multiplex PCR for Detection of Diarrheagenic Escherichia coli in a Diagnostic Microbiology Laboratory Setting

2016 ◽  
Vol 1 (2) ◽  
pp. 38-42 ◽  
Author(s):  
Khairun Nessa ◽  
Dilruba Ahmed ◽  
Johirul Islam ◽  
FM Lutful Kabir ◽  
M Anowar Hossain
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Clinical Laboratory ◽  
Proteinase K ◽  
Microbiology Laboratory ◽  
Pcr Assay ◽  
E Coli ◽  
Diarrheagenic Escherichia Coli ◽  
Multiplex Pcr Assay ◽  
Diagnostic Microbiology

A multiplex PCR assay was evaluated for diagnosis of diarrheagenic Escherichia coli in stool samples of patients with diarrhoea submitted to a diagnostic microbiology laboratory. Two procedures of DNA template preparationproteinase K buffer method and the boiling method were evaluated to examine isolates of E. coli from 150 selected diarrhoeal cases. By proteinase K buffer method, 119 strains (79.3%) of E. coli were characterized to various categories by their genes that included 55.5% enteroaggregative E. coli (EAEC), 18.5% enterotoxigenic E. coli (ETEC), 1.7% enteropathogenic E. coli (EPEC), and 0.8% Shiga toxin-producing E. coli (STEC). Although boiling method was less time consuming (<24 hrs) and less costly (<8.0 US $/ per test) but was less efficient in typing E. coli compared to proteinase K method (41.3% vs. 79.3% ; p<0.001). The sensitivity and specificity of boiling method compared to proteinase K method was 48.7% and 87.1% while the positive and negative predictive value was 93.5% and 30.7%, respectively. The majority of pathogenic E. coli were detected in children (78.0%) under five years age with 53.3% under one year, and 68.7% of the children were male. Children under 5 years age were frequently infected with EAEC (71.6%) compared to ETEC (24.3%), EPEC (2.7%) and STEC (1.4%). The multiplex PCR assay could be effectively used as a rapid diagnostic tool for characterization of diarrheagenic E. coli using a single reaction tube in the clinical laboratory setting.Bangladesh J Med Microbiol 2007; 01 (02): 38-42

Antagonistic activity of Bacillus subtilis strains isolated from various sources

2018 ◽  
Vol 8 (2) ◽  
pp. 354-364
Author(s):  
A. N. Irkitova ◽  
A. V. Grebenshchikova ◽  
A. V. Matsyura
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Wild Strain ◽  
Fish Farming ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
E Coli ◽  
Long Period ◽  
Test Culture ◽  
Agar Media

<p>An important link in solving the problem of healthy food is the intensification of the livestock, poultry and fish farming, which is possible only in the adoption and rigorous implementation of the concept of rational feeding of animals. In the implementation of this concept required is the application of probiotic preparations. Currently, there is an increased interest in spore probiotics. In many ways, this can be explained by the fact that they use no vegetative forms of the bacilli and their spores. This property provides spore probiotics a number of advantages: they are not whimsical, easily could be selected, cultivated, and dried. Moreover, they are resistant to various factors and could remain viable during a long period. One of the most famous spore microorganisms, which are widely used in agriculture, is <em>Bacillus subtilis</em>. Among the requirements imposed to probiotic microorganisms is mandatory – antagonistic activity to pathogenic and conditional-pathogenic microflora. The article presents the results of the analysis of antagonistic activity of collection strains of <em>B. subtilis</em>, and strains isolated from commercial preparations. We studied the antagonistic activity on agar and liquid nutrient medias to trigger different antagonism mechanisms of <em>B. subtilis</em>. On agar media, we applied three diffusion methods: perpendicular bands, agar blocks, agar wells. We also applied the method of co-incubating the test culture (<em>Escherichia coli</em>) and the antagonist (or its supernatant) in the nutrient broth. Our results demonstrated that all our explored strains of <em>B. subtilis</em> have antimicrobial activity against a wild strain of <em>E. coli</em>, but to varying degrees. We identified strains of <em>B. subtilis</em> with the highest antagonistic effect that can be recommended for inclusion in microbial preparations for agriculture.</p><p><em><br /></em><em></em></p>

NGHIÊN CỨU KHẢ NĂNG BẤT HOẠT ESCHERICHIA COLI TRONG NƯỚC BẰNG TIA CỰC TÍM VỚI SỰ HỖ TRỢ CỦA THIẾT BỊ TẠO MÀNG CHẤT LỎNG

2020 ◽  
Vol 129 (4B) ◽  
Author(s):  
Đặng Thị Thanh Lộc ◽  
Lê Văn Tuấn
Keyword(s):  
Escherichia Coli ◽  
E Coli

Công nghệ khử trùng nước không tạo ra các sản phẩm phụ độc hại ngày càng thu hút nhiều quan tâm nghiên cứu trong những năm gần đây. Nghiên cứu này trình bày kết quả khử trùng Escherichia coli trong nước bằng tia UV kết hợp với thiết bị tạo màng chất lỏng (LFFA). Sự nhạy cảm của vi khuẩn với sự khử trùng bằng UV hoặc UV/LFFA được xác định tại các điều kiện khác nhau của liều UV, tốc độ sục khí và mật độ ban đầu của vi khuẩn. Kết quả nghiên cứu cho thấy khử trùng bằng tia UV kết hợp với LFFA mang lại hiệu quả khử trùng cao hơn so với UV thông thường. Cụ thể, sự kết hợp của UV (liều UV = 20,83 mJ/cm2 và nhiệt độ phòng) và LFFA (tốc độ sục khí = 1,5 L/phút) đã bất hoạt hoàn toàn 5,4 log E. coli trong vòng 60 phút. Trong khi tại cùng một liều UV tương tự, khử trùng bằng tia UV chỉ giảm được 4,3 log vi khuẩn sau 75 phút. Nghiên cứu này hứa hẹn một khả năng áp dụng phương pháp hiệu quả để tăng cường hoạt tính diệt khuẩn của tia UV, nhằm giải quyết các mối quan tâm gần đây trong khử trùng nước.

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