GONÇALVES, Thially Braga. Atividade antimicrobiana e mecanismos de ação do óleo essencial de Plectranthus amboinicus frente a cepas multirresistentes de Klebsiella pneumoniae. 2012. 81 f. Dissertação (Mestrado em Microbiologia Médica) - Universidade Federal do Ceará. Faculdade de Medicina, Fortaleza, 2012. / Submitted by denise santos (denise.santos@ufc.br) on 2014-11-19T12:42:01Z No. of bitstreams: 1 2012_dis_tbgonçalves.pdf: 4468289 bytes, checksum: 6e50311d5664c85036bc762088435eeb (MD5) / Approved for entry into archive by denise santos(denise.santos@ufc.br) on 2014-11-19T12:42:47Z (GMT) No. of bitstreams: 1 2012_dis_tbgonçalves.pdf: 4468289 bytes, checksum: 6e50311d5664c85036bc762088435eeb (MD5) / Made available in DSpace on 2014-11-19T12:42:47Z (GMT). No. of bitstreams: 1 2012_dis_tbgonçalves.pdf: 4468289 bytes, checksum: 6e50311d5664c85036bc762088435eeb (MD5) Previous issue date: 2012 / This work describes the first study about the antimicrobial activity and mechanisms of action of the subinihibitory and inhibitory concentrations essential oil from leaves of Plectranthus amboinicus against standard strain of Klebsiella pneumoniae and multresistant clinical isolates of the bacterium. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC), the rate of killing and the pH sensitivity of the essential oil were determined through microplate-microdilution tests. Subinihibitory and inhibitory concentrations of Plectranthus amboinicus essential oil were tested in order to check their action on K. pneumoniae membrane permeability, capsule expression, urease activity and cell morphology. The MIC and MBC of the essential oil were 0.09± 0.01% and resulted remarkably in complete inhibition of the bacterial growth after 2 hours, when the bacteria were exposed to twice the MIC of the essential oil. A better MIC was found when neutral or alkaline pH broth was used. Cristal violet uptake which represented altered permeability was considered to be significant when twice the MIC of the essential oil was used compared to the untreated group (p<0.05); Reduction of the urease activity could be found when all the subinihibitory concentrations were tested compared to the untreated group (p< 0.001). Is the result was an indicative that there was alteration on the capsule expression and membrane leakage, which could be demonstrated by the Anthony´s method and atomic force microscopy, respectively. / O trabalho descreve o primeiro estudo sobre a atividade antimicrobiana e mecanismos de ação de concentrações sub-inibitórias e inibitórias do óleo essencial das folhas de Plectranthus amboinicus contra uma cepa padrão de Klebsiella pneumoniae e cepas obtidas de isolados clínicos multirresistentes. A concentração inibitória mínima (CIM), concentração bactericida mínima (CBM), a taxa de morte e o efeito do pH na ação do óleo essencial foram analisadas através de testes de microdiluição em microplacas. Concentrações sub-inibitórias e inibitórias do óleo essencial foram testadas para verificar sua ação sobre permeabilidade da membrana, expressão de cápsula, atividade da urease e morfologia celular de K. pneumoniae. A CIM e CBM do óleo essencial foram de 0,09 ± 0,01% e resultou notavelmente na inibição completa do crescimento bacteriano após 2 horas, quando as bactérias foram expostas a duas vezes a CIM do óleo essencial. A melhor CIM foi encontrada quando o pH neutro ou alcalino foi usado. Captação de Cristal violeta foi considerada significativa quando o dobro da CIM do óleo essencial foi usado (p <0,05). Inibição da atividade da urease foi observada em todas concentrações sub-inibitórias testadas, quando comparada ao grupo não tratado (p<0,001). Verificou-se ainda alteração na expressão da cápsula e alterações na membrana, verificadas pelas técnicas de Anthony e por microscopia de força atômica, respectivamente.

No description available.

The genus Klebsiella belongs to the family Enterobacteriaceae. Eighty types of Klebsiella have been serologically classified using the capsular polysaccharides as antigens. In order to understand the chemical basis of serological reactions, structural studies of the capsular polysaccharides from three strains of Klebsiella, namely, K5, K62 and K18 were carried out by means of conventional methods (such as hydrolysis, methylation and periodate oxidation) as well as modern methods (such as circular dichroism (c.d.) for the assignment of the D or L configuration of monosaccharides, gas-liquid chromatography (g.l.c.) and mass spectrometry for isolation and identification of sugar moieties). In the course of the present investigation, p.m.r. spectroscopy at 95° for the assignment of anomeric configurations of the constituent sugars, and Sephadex gel filtration for the separation of a series of acidic oligosaccharides obtained from the partial hydrolysis of polysaccharides for sequential analysis have been developed. The repeating units of K5, K62 and K18 are as follows. The structure of K5 capsular polysaccharide lacks any side chain and is also unusual in affording the first example of a 4,6-0-(l-carboxyethylidene)-D-raannose unit In a natural product. Capsular polysaccharide of K.62 belongs to the prevailing structural pattern so far published in this genus which is composed of a repeating unit involving a single sugar in the side chain with three to four monosaccharides in the backbone. Capsular polysaccharide from K18 is unusua complex in that it consists of two L-rhamnoses in the hexasaccharlde repeat unit which renders the polysaccharide less viscous and acid labile. Finally, an attempted immunological study on K5 is briefly discussed. / Science, Faculty of / Chemistry, Department of / Graduate

Eighty-one serologically distinct strains of Klebsiella bacteria are known. The capsular polysaccharides from these bacteria are their antigenic determinants and in order to help understand the chemical basis of serological differentiation, the detailed chemical structures of these polysaccharides are being determined. The capsular polysaccharides isolated from Klebsiella serotypes K32, K36 and K70 are presented here and have been established using many different chemical techniques. Methyla- tion, partial hydrolysis, periodate oxidation and 3-elimination procedures have yielded analysable subunits of the polysaccharides Extensive use has been made of n.m.r. spectroscopy (¹H and 13 C), mass spectrometry, gas-liquid chromatography and gel filtration in the isolation and identification of the products obtained from the various degradative techniques. The repeating unit structures of K32, K36 and K70 are shown to be as follows: [chemical structures]. Some features of special interest in these structures include: the extreme acid lability of the pyruvate acetal when linking hydroxyls on C₃ and C₄ of a 2-linked L-rharanose residue (K32, K70); the existence of a 3-Lj-rhamnose unit in the structure of K32; and the presence of the pyruvate acetal on only 50% of the linear, six sugar, repeating units of K70. It is also interesting to note that while K70 and K36 have almost the same quantitative composition the chemical structures are markedly different. An efficient means of isolating large quantities of single repeating units of the Klebsiella polysaccharides using glycanase enzymes borne and utilised by specific bacteriophage, is demonstrated. A bacteriophage specific for Klebsiella K32 has been propagated, purified and used to depolymerise K32 polysaccharide. Analysis of the resulting oligosaccharides has shown the glycanase enzyme to be a a-rhamnosidase which cleaves K32 as shown below. [chemical structure] The degradation via bacteriophage is a new area of research and the work described here is only preliminary and as such is presented as an appendix. / Science, Faculty of / Chemistry, Department of / Graduate

Tetracyanonickelate (K2(Ni(CN)4), TCN) is one of the most toxic organics to living organisms. In this study, Klebsiella oxytoca (K. oxytoca) SYSU-011 (a cyanide- degrading bacterium), which was isolated from the wastewater of a metal-plating plant, was shown to be able to biodegrade TCN under anaerobic conditions. Two different media (Burk and NFG) were used to grow K. oxytoca. Results indicate that higher TCN biodegradation rate was observed when Burk medium was used as the growth media for K. oxytoca. In the nitrogen source addition experiment, TCN degradation was inhibited by the addition of nitrite. In the carbon source addition experiment, TCN degradation was enhanced by the addition of glucose and fructose. These findings would be helpful in designing a practical in situ or on-site treatment system inoculated with K. oxytoca for the treatment of TCN-containing wastewater.

published_or_final_version / Microbiology / Master / Master of Medical Sciences

Univ., Diss.--München, 1999.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 180-186).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.