Thesis (Ph.D.)--Washington State University, December 2005. / Includes bibliographical references (p. 70-76).

Thesis (doctoral)--Lund University, 1994. / Added t.p. with thesis statement inserted.

No description available.

Copy of author's previously published works inserted. Bibliography: leaves 183-220. Three antimicrobial peptides, maculatin 1.1, uperin 3.6 and caerin 4.1 have been isolated from the respective skin glands of the Australian amphibians Litoria genimaculata, Uperoleia mjobergii and Litoria caerulea. To gain a deeper insight into their mechanisms of action, three dimensional structural studies have been conducted using circular dichroism, two-dimensional nuclear resonance and computer modelling techniques. The role of central flexibility within antibiotic peptides in their interaction with bacterial membranes is also discussed.

Submitted by LUCAS DE PAULA RAMOS null (lucas93paula@hotmail.com.br) on 2017-01-20T14:09:20Z No. of bitstreams: 1 Dissertação (correções biblioteca).pdf: 4172563 bytes, checksum: 3cfab803e9b5a294021bdd02082d4128 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2017-01-24T17:04:02Z (GMT) No. of bitstreams: 1 ramos_lp_me_sjc.pdf: 4172563 bytes, checksum: 3cfab803e9b5a294021bdd02082d4128 (MD5) / Made available in DSpace on 2017-01-24T17:04:02Z (GMT). No. of bitstreams: 1 ramos_lp_me_sjc.pdf: 4172563 bytes, checksum: 3cfab803e9b5a294021bdd02082d4128 (MD5) Previous issue date: 2016-12-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo do trabalho foi investigar se os extratos de Pfaffia paniculata K. e Juglans regia L. possuem ação antifúngica, antibacteriana e toxicidade celular, com testes in vitro. Para os testes antifúngicos foram utilizadas cepas ATCC de Candida spp., e para os testes antibacterianos foram utilizadas cepas ATCC de Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans e Pseudomonas aeruginosa. Para a atividade antimicrobiana primeiramente foram determinados os valores da Concentração Inibitória Mínima (CIM) e da Concentração Microbicida Mínima (CMM) dos extratos pelo método de microdiluição em caldo, segundo Clinical and Laboratory Standards Institute (CLSI). Os micro-organismos que apresentaram CMM foram selecionados para os testes em biofilme, no qual foi preparado em fundo de placa com 96 poços, por 48 h. Após os biofilmes foram tratados por 5 min. utilizando as concentrações de 200, 100 e 50 mg dos extratos. Para mensuração da biomassa foi utilizado o teste de Cristal violeta (CV), e para avaliar a atividade metabólica foi utilizado o teste de MTT. A citotoxicidade foi avaliada sobre fibroblastos gengivais humanos (FMM-1) utilizando os mesmos parâmetros de tratamento utilizados para os testes em biofilmes. Foram avaliadas a viabilidade celular pelos testes de MTT, vermelho neutro e cristal violeta. Os dados obtiveram distribuição normal e foram analisados por ANOVA e teste de Tukey, com significância de 5% (p<0.05%). O extrato de P. paniculata demostrou ação antifúngica em biofilmes, com reduções médias de 29,4 e 42,7% nos testes de CV e MTT. Já a ação antibacteriana foi restrita a S. mutans e P. aeruginosa com reduções médias de 15,7 e 28,6% nos respectivos testes. O extrato de J. regia também demostrou ação antifúngica com redução média de 22,2% na biomassa e 31,4% na atividade metabólica. A ação antimicrobiana ficou restrita a P. aeruginosa com reduções médias de 17,7 e 15,6%, indicados pelos testes de CV e MTT. Quanto a citotoxicidade, a média entre os três testes realizados, indicou que após exposição ao extrato de P. paniculata 58,8% das células continuaram viáveis e para J. regia a viabilidade foi de 65,1%. Conclui-se queo extrato de P. paniculata demostrou ação antifúngica sobre todas as cepas de Candida spp. testadas e demostrou ação antibacteriana para P. aeruginosa e S. mutans. As concentrações de 200, 100 e 50 mg do extrato demostraram ser citotóxicas conforme nova diretriz de toxicidade. J. regia demostrou ação antifúngica sobre todas as cepas de Candida spp. testadas e demostrou ação antibacteriana sobre P. aeruginosa. Apenas a concentração de 200 mg do extrato se mostrou tóxica a FMM-1. / The aim of this study was to investigate whether extracts of Pfaffia paniculata K. and Juglans regia L. have antifungal, antibacterial and cellular toxicity, with in vitro tests. ATCC strains of Candida spp. Were used for antifungal tests, and ATCC strains of Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans and Pseudomonas aeruginosa were used for the antibacterial tests. For the antimicrobial activity, the values of the Minimum Inhibitory Concentration (MIC) and the Minimal Microbicidal Concentration (CMM) of the extracts were determined by the microdilution method in broth, according to Clinical and Laboratory Standards Institute (CLSI). The microorganisms that presented CMM were selected for the biofilm tests, in which it was prepared on a 96-well plate bottom for 48 h. After the biofilms were treated for 5 min. Using the concentrations of 200, 100 and 50 mg of the extracts. To measure the biomass, the Violet Crystal test (CV) was used, and the MTT test was used to evaluate the metabolic activity. Cytotoxicity was assessed on human gingival fibroblasts (FMM-1) using the same treatment parameters used for biofilm tests. Cell viability was evaluated by the MTT, neutral red and violet crystal tests. The data obtained normal distribution and were analyzed by ANOVA and Tukey test, with significance of 5%. The extract of P. paniculata showed antifungal action in biofilms, with average reductions of 29.4 and 42.7% in CV and MTT tests; The antibacterial action was restricted to S. mutans and P. aeruginosa with mean reductions of 15.7 and 28.6% in the respective tests. The extract of J. regia also demonstrated antifungal action with an average reduction of 22.2% in biomass and 31.4% in metabolic activity. The antimicrobial action was restricted to P. aeruginosa with mean reductions of 17.7 and 15.6%, indicated by CV and MTT tests. As for cytotoxicity, the mean of the three tests carried out indicated that after exposure to P. paniculata extract 58.8% of the cells remained viable and for viability the viability was 65.1%. In conclusion the extract of P. paniculata showed antifungal action on all strains of Candida spp. Tested and demonstrated antibacterial action for P. aeruginosa and S. mutans. The concentrations of 200, 100 and 50 mg of the extract proved to be cytotoxic according to the new toxicity guideline. J. regia demonstrated antifungal action on all strains of Candida spp. Tested and demonstrated antibacterial action on P. aeruginosa. Only the 200 mg concentration of the extract was shown to be toxic to FMM-1.

nÃo hà / Diarreia nosocomial (DN) à uma infecÃÃo relacionada à assistÃncia à saÃde (IRAS) com incidÃncia e severidade crescentes. PropÃe-se determinar a incidÃncia da DN, os fatores de risco e a incidÃncia da doenÃa associada a Clostridium difficile (C. difficile). Para isso, um estudo caso â controle, pareando pacientes por idade, sexo, perÃodo de admissÃo, clÃnica e diagnÃstico, foi conduzido, de 06/ fev/12 a 05/fev/13, no Hospital UniversitÃrio da UFC. Casos &#822; pacientes com DN e Controles &#822; pacientes sem DN. Definiu-se DN como fezes lÃquidas, trÃs ou mais vezes em 24 horas, com duraÃÃo superior a 12 horas, sem outras causas inflamatÃrias ou procedimentos diagnÃsticos. DN foi detectada mediante busca ativa, visitando-se os pacientes das Unidades de Hematologia, Transplante HepÃtico e Renal. O teste ELISA TOX A/B II foi utilizado para detectar as toxinas A e/ou B e diagnosticar doenÃa associada ao C. difficile. Demais IRAS foram investigadas por intermÃdio de fichas de notificaÃÃo de infecÃÃo hospitalar (IH). O Ãndice geral de IH foi de 7,17%. A incidÃncia da DN nas enfermarias de Hematologia, Transplante HepÃtico e Renal foi 4,80% (44/925) e da DN associada ao C. difficile 0,12% (01/925). Detectaram-se toxinas A/B de C. difficile em caso [1/43 (2,32%)] e controles [3/72 (4,17%)]. DN foi significantemente associada ao uso prÃvio > 6 antimicrobianos por paciente, alÃm do uso prÃvio de ciprofloxacina, metronidazol, polimixina B e dieta enteral (p&#8804; 0,05). Pacientes com DN permaneceram mais tempo internados, tiveram mais vÃmitos, cÃlicas e febre, verificando-se alta significÃncia estatÃstica (p&#8804; 0,05). Outras IRAS identificadas, nos casos e controles, foi infeÃÃo do trato urinÃrio 54% (15/28), seguida da corrente sanguÃnea 32% (8/28), do sÃtio cirÃrgico 11% (3/28) e de infecÃÃo de partes moles 4% (1/28). DN impÃe riscos aos pacientes jà debilitados. Os dados demonstram a presenÃa endÃmica do C. difficile. A atualizaÃÃo da epidemiologia local orienta medidas de controle da IH, como uso judicioso de antibiÃticos, cautelas com a dieta enteral e precauÃÃes de contato, para os pacientes com diarreia nosocomial. / Nosocomial diarrhea (ND) is a healthcare - associated infections (HAI) with increasing incidence and severity. It is proposed to determine the incidence of ND, the associated risk factors and the incidence of disease associated to Clostridium difficile (C. difficile). For this, a case - control study, pairing patients by age, sex, length of admission, and clinical diagnosis was conducted 06 / Feb/12 to 05/Fev/13 in the University Hospital of the UFC. Cases: patients with DN and controls: patients without ND. Nosocomial diarrhea is defined as watery stools, three or more times within 24 hours, over 12 hours without further diagnostic procedures or inflammatory causes. ND was detected by active surveillance, visiting the patients of Hematology, Liver and Renal Transplant. DN was defined as loose stools, 3 or more times in 24 hours, with duration longer than 12 hours, without other inflammatory causes or diagnostic procedures. The ELISA TOX A / B II test was used to detect toxin A and/or B and to diagnose C. difficile associated disease. Others HAI were investigated by the notification records of nosocomial infection (NI). The overall rate of Nosocomial infection was 7.17 %. The incidence of DN in the wards of Hematology, Liver and Renal Transplant was 4.80% (44/925) and C. difficile associated with DN was 0.12 % (01/925). Toxins A/B were detected in the case of C. difficile [1/43 (2.32%)] and controls [3/72 (4.17%)]. DN was significantly associated with previous use > 6 antimicrobials per patient, beyond the prior use of ciprofloxacin, metronidazole, polymyxin B and enteral feeding (p &#8804; 0.05). Patients with ND remained in hospital longer, had more vomiting, cramps and fever, verifying high statistical significance (p &#8804; 0.05). Other identified HAI were mainly urinary infection 54% (15/28), followed by bacterial bloodstream infection 32% (8/28), surgical site infection 11% (3/28) and soft tissue infection 4% (1/28). ND entails risks to the already debilitated patients. The data demonstrate the presence of endemic C. difficile. The updated of the local epidemiology guide control measures NI, such as judicious use of antibiotics, enteral feeding precautions and contact precautions for patients with nosocomial diarrhea.

The Sonochemistry Centre at Coventry University is one of a group of organisations working on a project to develop a new technology for producing antimicrobial textiles. This technology involves the use of an ultrasonic process (sonochemical) to generate and impregnate fabrics with antibacterial metal oxide nanoparticles. The expectation is that these textiles can be produced at an affordable price for routine use in hospitals as uniforms, curtains, hospital bed sheets and linen. The aim of this PhD project was to assess the antibacterial activity of fabrics impregnated with ZnO and CuO NPs against a variety of Gram positive and Gram negative bacteria. The testing was principally carried out according to the absorption method from ISO 20743:2007. Research was also extended to compare different methods of assessing antibacterial activity of textile fabrics. These included disc diffusion tests and shake flask tests in saline or nutrient broth. Overall the results from absorption tests demonstrated that both the ZnO and CuO impregnated fabrics showed very good levels of antibacterial activity (A>2) against the test bacteria (Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa). During the optimisation of lab scale process to the pilot scale, two different types of CuO fabrics were produced to test and compare the antibacterial activity. One type of fabrics were impregnated with pre-made CuO nanoparticles by a ‘throwing the stones’ technology termed TTS and the other with sonochemically formed nanoparticles (in-situ), same as the lab process. The results indicated that the fabrics impregnated with sonochemically formed NPs displayed better antibacterial activity than the pre-made NPs. Leaching of the antibacterial agents in to saline was investigated using a shake flask method. CuO and ZnO coated fabrics prepared at laboratory scale were tested against Staphylococcus aureus, Acinetobacter baumannii and Escherichia coli. It was found that leachates prepared by shaking the fabrics in saline for 3 hours showed no antibacterial activity for CuO fabrics. However, leachates from ZnO fabrics showed an excellent activity after 24 ± 3 hours against all three bacterial species. Flow cytometry (FC) was investigated as an alternative to standard agar plate count (PC) methods for the determination of viable cell numbers. There was a general agreement between the results from agar plate counts and flow cytometry except that post incubation counts were greater with FC. The higher numbers of viable cells detected with FC may have been due to the presence of viable but not culturable cells (VBNC). Viable cells were observed by fluorescence microscopy in post incubation samples in which no viable cells were detected on nutrient agar plates. Cytotoxicity studies were conducted on ZnO and CuO fabrics from the pilot scale (both in-situ and TTS) against human dermal fibroblast cells (HDF) and human hepatocellular carcinoma cells (HepG2) using a MTT assay to determine cell viability. The results showed that ZnO and CuO are not toxic to HDF cells. However, cytotoxicity was seen in HepG2 cells with cell viability decreasing by > 14% for all the fabrics after 24 hours.

Pediococci are Gram-positive, non-spore forming lactic acid bacteria, LAB, that are commonly used in the industrial fermentation of vegetables and meat. On the other hand species of pediococci may constitute part of the secondary microflora as non-starter lactic acid bacteria, NSLAB, responsible for cheese ripening. This study was conducted to determine and isolate pediococci from South African farm-style cheese and to morphologically and physiologically characterize the pediococci isolates to a species level. Strains of Pediococcus species isolated from South African farm-style cheese were evaluated for the production of antimicrobial peptides, pediocins, and their effect against food pathogens Bacillus cereus ATCC 1178 and Listeria monocytogenes ATCC 7644. Eight farm-style cheeses namely pasteurized young Gouda (PYG), pasteurized matured Goude (PMG) as well as pasteurized matured Parmesan (PMP); un-pasteurised or raw milk aged Bouquet (RAB), aged Gouda (RAG) and matured Gouda (RMG) as well as goat cheese Gouda (:RGG) were chosen for the isolation of Pediococcus species. LAB were cultivated on MRS agar where logarithmic counts of LAB ranged from 6.90 cfu/g to 9.40 cfu/g. Microscopic examination of selected colonies identified 110 (18%) of 606 isolates as Gram-positive, catalase negative presumptive pediococci occurring in pairs, clusters and tetrads. Presumptive pediococci were distributed among five of the eight cheeses namely PYG, PMG, RAB, RAG and RMG in numbers of 33, 21,28, 12 and 16 respectively. Physiological characterization of presumptive pediococci isolates was determined under specific growth parameters, temperature, pH and salt (w/v). These isolates were characterized as P. acidilactici, forty-nine, and P. pentosaceus, sixty-one, isolates. For the antimicrobial assay three techniques namely, the agar disc, spot and overlay methods were evaluated. Comparisons on the sensitivity or susceptibility of two Lactococcus strains, L. diacetilactis NCDO 176 and L. lactis NCDO 605, to crude extract from P. acidilactici STI was assessed. The agar disc assay technique produced more reliable results compared to the other techniques and L. diacetilactis NCDO 176 was more susceptible to crude pediocin extract produced from P. acidilactici STI. A total of fifty-two strains (47%) from both species, twenty-seven (24%) P. acidilactici and twenty-five (23%) P. pentosaceus, exerted antagonism against L. diacetilactis NCDO 176 through the action of perdiocins. Among these strains thirteen (13%) of both species, seven (6%) P. acidilactici and six (7%) P. pentosaceus inhibited B. cereus ATCC 1178 while a total of thirty-seven strains (33%) of both species where, seventeen (15%) P. acidilactici and twenty (18%) P. pentosaceus showed inhibition against L. monocytogenes ATCC 7644. Among these strains inhibition of food pathogens was variable against L. monocytogenes ATCC 7644 and low against B. cereus ATCC 1178. Comparison of the antimicrobial activity of the two Pediococcus species showed similarity in the inhibition pattern, however, more strains of P. pentosaceus exerted antagonism against L. lactis NCDO 176 and L. monocytogenes ATCC 7644 compared to P. acidilactici. / Dissertation (MSc)--University of Pretoria, 2005. / Food Science / unrestricted

This work reports on the conjugation of differently shaped Pt nanoparticles (PtNPs) with ClGa(III) 5,10,15,20-tetrakis-(4-carboxyphenyl) porphyrin (1) as well as chloro - (5,10,15,20-tetrakis (4- (4- carboxy phenycarbonoimidoyl) phenyl) porphyrinato) gallium(III) (2) The work also reports on platination of dihydroxosilicon octacarboxyphthalocyanine (OH)₂SiOCPc (3) to give dihydroxosilicontris(diaquaplatinum)octacarboxyphthalocyanine (OH)₂SiOCPc(Pt)₃ (4). The resulting conjugates were used for photodynamic antimicrobial chemotherapy against S. aureus, E. coli and C. albicans. The degree of photo-inactivation is dependent on concentration of the conjugates, light dose (fluence) and illumination time. The log reduction obtained for 1 when conjugated to cubic PtNPs was 4.64 log (which indicate 99.99 percent of the bacteria have been killed), which is much higher than 3.94 log unit for 1-hexagonal PtNPs and 3.31 log units for 1-unshaped PtNPs. Complex 2 conjugated to hexagonal PtNPs showed 18 nm red shift in the Soret band when compared to 2 alone. Complex 2 and 2-hexagonal PtNPs as well showed promising photodynamic antimicrobial chemotherapy (PACT) activity against S. aureus, E. coli and C. albicans in solution where the log reduction obtained was 4.92, 3.76, and 3.95 respectively for 2-hexagonal PtNPs. The singlet oxygen quantum yields obtained were higher at 0.56 for 2-hexagonl PtNPs in DMF while that of 2 was 0.52 in the same solvent. This resulted in improved PACT activity for 2-hexagonal PtNPs compared to 2. Complex 4 showed slight blue shifting of the absorption spectrum when compared to complex 3 The antimicrobial activity of 4 were promising as the highest log reduction value was observed when compared to the porphyrin conjugates.

The rhodophytes or red seaweeds are an ancient group of organisms that are related to plants. Like terrestrial plants, they use secondary compounds to protect themselves from microbial infection and grazing by herbivores. However, unlike terrestrial plants, they produce mostly halogenated secondary compounds and rarely alkaloids. Osmundaria serrata (Rhodophyta) is found along the eastern South African coast and the Maldive Islands. Its descriptive common name is “red spirals” and the species is adapted to live in habitats with high wave action. Extracts from this seaweed had previously shown to have antimicrobial activity, but ecologically irrelevant microbes were used to test the extracts. In this study, ten bacteria were isolated from the surface of O. serrata and its habitat, and identified. Mostly aerobic and Gram-negative bacteria were isolated (Halomonas and Pseudomonas species) along with facultatively anaerobic forms (Vibrio spp.) and a Gram-positive (Marinococcus sp.). These were used in bioassays to compare the activity of extracts made from O. serrata and other seaweeds that occur in the same habitat. Marine bacteria are the initial colonizers in biofilm formation and subsequent fouling of surfaces in marine environments. The study of these bacteria in relation to their macroalgal hosts may help to control biofouling of surfaces that cause economic losses worldwide. A comparison was made between using agar dilution and microtitre methods for testing the antibacterial activity of an O. serrata extract. The microtitre method was found to be more sensitive than the agar dilution method. Possibly because e some of the bacteria on the petri plates (in the agar dilution method) were not in direct contact with the toxicant in the growth medium, but were in direct contact in the liquid medium of the wells in the microtitre plates. The extract from 0. serrata was the most active of the thirteen species of macroalgae collected from the same habitat and tested for antibacterial activity. Deformities in bacteria were observed in response to the 0. serrata extract. Increased capsule production and blebbing of the outer membranes were observed by transmission electron microscopy (negative staining). Lanosol diethyl ether was isolated from 0. serrata and tested for antibacterial activity. Lanosol is produced mainly by the rhodophytes, but it is also found in other macroalgae and fungi in lower concentrations. The compound inhibited the test bacteria with average MIC's of 0.27 ± 0.07 mg.mr1 (bacteriostatic) and 0.69 ± 0.15 mg.mr1 (bactericidal). Different forms of biofilm were observed by scanning electron microscopy on the thirteen species of macroalgae. These ranged from a very little biofilm covering on the calcified reds to complex communities on the other macroalgae. The treatment with OS04 vapour before fixation in glutaraldehyde preserved the biofilm structure better than no treatment and indicated that lipids are important in maintaining biofilm structure. Since a complex biofilm community was seen on the surface of 0. serrata, it is unlikely that lanosol functions as an antifouling agent. This chemical seems to multifunctional with antimicrobial and feeding deterrent activities. / Thesis (PhD (Botany))--University of Pretoria, 2006. / Plant Science / unrestricted