Vibrio vulnificus is a foodborne bacterial pathogen associated with raw oyster consumption. Shellfish depuration for 48 hours is a dynamic process where coliform bacteria are purged; however, this process is ineffective against V. vulnificus. The current study investigated the use of prolonged two-week depuration on V. vulnificus populations in Gulf Coast oysters. The study evaluated the impact of prolonged depuration on V. vulnificus fatty acid profile change and the ability to survive in simulated gastric fluid. Oyster depuration in seawater (10 or 22oC, 14 days) reduced V. vulnificus counts, but not to non-detectable level, indicating close ecological relationship between the pathogen and mollusk. Greatest V. vulnificus count reductions were seen in 12 ppt 10°C seawater (2.7 log10 CFU/g) and in 20 ppt 22°C seawater (2.8 logs). Mesophilic vibrios dominated the overall microflora of freshly harvested oysters, while refrigeration selected for psychrotrophic bacteria. Depuration at 22°C retained dominance of mesophilic vibrios, including pathogenic species. Although aerobic plate counts were lower in 22°C depurated oysters (5.0 logs vs 6.0 logs), depuration at 10°C had little to no advantage over 22°C in terms of vibrio population reduction. Use of prolonged depuration remains economically questionable since this method failed to completely eliminate V. vulnificus. Starved V. vulnificus behavior in artificial seawater showed that low temperature (4oC) and high seawater salinity (35 ppt) contributed to pathogen population reduction. Starved V. vulnificus did not adjust membrane fluidity to storage temperature within the investigated time frame. However, a significant fatty acid switch from C18:1w7c to C18:1w6c by double bond relocation was observed. The relocation was faster at ambient temperatures compared to refrigerated temperatures. The majority of V. vulnificus foodborne infections occur during warm summer months. Vibrio vulnificus ATCC 27562 was significantly less resistant (3.7 min D-value) to simulated gastric fluid (pH 4.0) after 7-day storage at 4oC compared to the control (7.8 min D-value). Therefore, greater gastric fluid sensitivity of the pathogen may occur in winter-harvested oysters and may partially explain the low number of winter outbreaks.

Water is considered the most vital resource on earth and its quality is deteriorating. Not all residents living in South Africa‘s rural areas have access to treated drinking water, and use water from rivers, dams, and wells. The quality of these resources is unknown, as well as the effects of the bacteria in the water on human health. The heterotrophic plate count (HPC) method is a globally used test to evaluate microbial water quality. According to South African water quality guidelines, water of good quality may not contain more than a 1 000 coliforming units (CFU)/mℓ. There is mounting evidence that HPC bacteria may be hazardous to humans with compromised, underdeveloped, and weakened immune systems. In this study the pathogenic potential of HPC bacteria was investigated. Samples were collected from boreholes in the North West Province and HPCs were enumerated with a culture-based method. Standard physico-chemical parameters were measured for the water. Different HPC bacteria were isolated and purified and tested for α- or β-haemolysis, as well as the production of extracellular enzymes such as DNase, proteinase, lecithinase, chondroitinase, hyaluronidase and lipase, as these are pathogenic characteristics. The isolates were identified with 16S rRNA gene sequencing. The model for the human intestine, Hutu-80 cells, were exposed to the potentially pathogenic HPC isolates to determine their effects on the viability of the human cells. The isolates were also exposed to different dilutions of simulated gastric fluid (SGF) to evaluate its effect on the viability of bacteria. Antibiotic resistant potential of each isolate was determined by the Kirby-Bauer disk diffusion method. Three borehole samples did not comply with the physico-chemical guidelines. Half of the samples exceeded the microbial water quality guideline and the greatest CFU was 292 350 CFU/mℓ. 27% of the isolate HPC bacteria were α- or β- haemolytic. Subsequent analysis revealed the production of: DNase in 72%, proteinase in 40%, lipase and lecithinase in 29%, hyaluronidase in 25% and least produced was chondroitinase in 25%. The HPC isolates identified included: Alcaligenes faecalis, Aeromonas hydrophila and A. taiwanesis, Bacillus sp., Bacillus thuringiensis, Bacillus subtilis, Bacillus pumilus, Brevibacillus sp., Bacillus cereus and Pseudomonas sp. All the isolates, except Alcaligenes faecalis, were toxic to the human intestinal cells to varying degrees. Seven isolates survived exposure to the most diluted SGF and of these, four isolates also survived the intermediate dilution but, only one survived the highest SGF concentration. Some isolates were resistant to selected antibiotics, but none to neomycin and vancomycin. Amoxillin and oxytetracycline were the least effective of the antibiotics tested. A pathogen score was calculated for each isolate based on the results of this study. Bacillus cereus had the highest pathogen index with declining pathogenicity as follows: Alcaligenes faecalis > B. thuringiensis > Bacillus pumilus > Pseudomonas sp. > Brevibacillus > Aeromonas taiwanesis > Aeromonas hydrophila > Bacillus subtilis > Bacillus sp. The results of this study prove that standard water quality tests such as the physico-chemical and the HPC methods are insufficient to provide protection against the effects of certain pathogenic HPC bacteria. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014

Water is considered the most vital resource on earth and its quality is deteriorating. Not all residents living in South Africa‘s rural areas have access to treated drinking water, and use water from rivers, dams, and wells. The quality of these resources is unknown, as well as the effects of the bacteria in the water on human health. The heterotrophic plate count (HPC) method is a globally used test to evaluate microbial water quality. According to South African water quality guidelines, water of good quality may not contain more than a 1 000 coliforming units (CFU)/mℓ. There is mounting evidence that HPC bacteria may be hazardous to humans with compromised, underdeveloped, and weakened immune systems. In this study the pathogenic potential of HPC bacteria was investigated. Samples were collected from boreholes in the North West Province and HPCs were enumerated with a culture-based method. Standard physico-chemical parameters were measured for the water. Different HPC bacteria were isolated and purified and tested for α- or β-haemolysis, as well as the production of extracellular enzymes such as DNase, proteinase, lecithinase, chondroitinase, hyaluronidase and lipase, as these are pathogenic characteristics. The isolates were identified with 16S rRNA gene sequencing. The model for the human intestine, Hutu-80 cells, were exposed to the potentially pathogenic HPC isolates to determine their effects on the viability of the human cells. The isolates were also exposed to different dilutions of simulated gastric fluid (SGF) to evaluate its effect on the viability of bacteria. Antibiotic resistant potential of each isolate was determined by the Kirby-Bauer disk diffusion method. Three borehole samples did not comply with the physico-chemical guidelines. Half of the samples exceeded the microbial water quality guideline and the greatest CFU was 292 350 CFU/mℓ. 27% of the isolate HPC bacteria were α- or β- haemolytic. Subsequent analysis revealed the production of: DNase in 72%, proteinase in 40%, lipase and lecithinase in 29%, hyaluronidase in 25% and least produced was chondroitinase in 25%. The HPC isolates identified included: Alcaligenes faecalis, Aeromonas hydrophila and A. taiwanesis, Bacillus sp., Bacillus thuringiensis, Bacillus subtilis, Bacillus pumilus, Brevibacillus sp., Bacillus cereus and Pseudomonas sp. All the isolates, except Alcaligenes faecalis, were toxic to the human intestinal cells to varying degrees. Seven isolates survived exposure to the most diluted SGF and of these, four isolates also survived the intermediate dilution but, only one survived the highest SGF concentration. Some isolates were resistant to selected antibiotics, but none to neomycin and vancomycin. Amoxillin and oxytetracycline were the least effective of the antibiotics tested. A pathogen score was calculated for each isolate based on the results of this study. Bacillus cereus had the highest pathogen index with declining pathogenicity as follows: Alcaligenes faecalis > B. thuringiensis > Bacillus pumilus > Pseudomonas sp. > Brevibacillus > Aeromonas taiwanesis > Aeromonas hydrophila > Bacillus subtilis > Bacillus sp. The results of this study prove that standard water quality tests such as the physico-chemical and the HPC methods are insufficient to provide protection against the effects of certain pathogenic HPC bacteria. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2014

Submitted by Fernando Bombarda Oda null (fer_oda@fcfar.unesp.br) on 2017-07-20T17:23:30Z No. of bitstreams: 1 Dissertação_Fernando_Oda_Final.pdf: 7648101 bytes, checksum: f78680181e6caaa8a443897d877a8eae (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-07-21T18:30:59Z (GMT) No. of bitstreams: 1 oda_fb_me_arafcf_parc.pdf: 1138705 bytes, checksum: a9ec30f0d79f53facd0d1b055e2a1bc4 (MD5) / Made available in DSpace on 2017-07-21T18:30:59Z (GMT). No. of bitstreams: 1 oda_fb_me_arafcf_parc.pdf: 1138705 bytes, checksum: a9ec30f0d79f53facd0d1b055e2a1bc4 (MD5) Previous issue date: 2017-06-19 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Casearia sylvestris Swartz, conhecida como guaçatonga, está distribuída em todo Brasil e é muito utilizada na medicina popular, com registro etnofarmacológico desde 1877. Muitos desses usos, como o antiofídico, antiulcerogênico e antiinflamatório já foram comprovados em estudos farmacológicos, os quais mostraram também a baixa toxicidade aguda por via oral de seus derivados vegetais. Estudos in vivo revelaram que os diterpenos clerodânicos são os responsáveis pelas atividades antiulcerogênica e anti-inflamatória de C. sylvestris, o que valoriza ainda mais o uso medicinal desta planta. Entretanto, a constatação de que os diterpenos clerodânicos podem sofrer degradação em meio ácido levantaram dúvidas sobre quais substâncias realmente chegam aos receptores e têm atividade: diterpenos ou seus produtos de degradação? Para elucidar essa questão, os diterpenos clerodânicos isolados casearina J (cas J) e O (cas O) foram submetidos isoladamente à degradação ácida em fluido gástrico simulado sem enzimas (PDA) e, posteriormente, metabolizados com enzimas hepáticas da fração S9 (PDA-ME). A metabolização direta dos diterpenos com a fração S9 também foi realizada (PME). As respectivas casearinas remanescentes foram quantificadas em todos os produtos de metabolização. Posteriormente, foram conduzidos ensaios de síntese e/ou liberação de óxido nítrico em macrófagos RAW 267.7 estimulados por LPS in vitro. Para a determinação estrutural dos derivados formados foram utilizadas técnicas cromatográficas (CLAEDAD) e espectrométricas (CLUE-EM, RMN de 1H e 13C). Foram identificadas dez substâncias formadas após degradação ácida da cas J (PDA-J), além da casearina remanescente (5,05%) e seu epímero (PDA-J8). As estruturas propostas desses produtos resultaram da hidrólise do grupamento éster em C-18 (PDA-J1), hidrólise do grupamento éster em C-19 (PDA-J3), formação de dialdeído após quebra do anel diacetálico C (PDA-J2, majoritário), e adições nos grupos aldeídos do PDA-J2 de uma molécula de água (PDJ-7), uma (PDA-J4 e PDA-J4.1) ou duas de etanol (PDJ-5) e hidrólise do éster em C-18 do PDA-J2 (PDJ-6). Foram identificadas nove substâncias formadas após degradação ácida da cas O, além da casearina remanescente (13,1%). Suas estruturas resultaram da hidrólise dos grupos ésteres em C-18 (PDA-O1) e C-19 (PDA-O3), formação do dialdeído após quebra do anel C (PDA-O2, majoritário), adições nos grupos aldeídos do PDA-O2 de uma (PDA-O4 e PDA-O 4.1) ou duas moléculas de etanol (PDA-O5) e hidrólise do éster em C-7 do PDA-O2 (PDA-O5), além da hidrólise do grupamento esterificado em C-6 do PDA-O5 (PDA-O6 ou PDA-O6.1). A metabolização da cas J pela fração S9 gerou duas substâncias correspondentes à quebra do butanoato em C-18 (PME-J1) e formação do seu epímero (PME-J2), permanecendo 36,8% íntegra. Em relação à metabolização da cas O, 36,5% permaneceu íntegra, e ocorreu a formação de uma molécula após quebra dos substituintes esterificados em C-18 e C-19 (PME-O1) e de outra após a formação do dialdeído no anel C (PME-O2). As análises indicaram que as metabolizações enzimáticas dos PDA resultaram nas mesmas substâncias. Os ensaios em macrófagos estimulados por LPS in vitro mostraram que os produtos de degradação ácida e/ou metabolização enzimática das casearinas não têm atividade antiinflamatória in vitro na inibição da liberação e/ou produção de NO, igualmente às casearinas J e O íntegras. / Casearia sylvestris Swartz known as guaçatonga is distributed throughout Brazil and has been widely used in folk medicine since 1877. Many of these uses, such as anti-fungal, antiulcerogenic and anti-inflammatory, have already been proven in pharmacological studies, also demonstrating low acute oral toxicity. In vivo studies have shown that clerodane diterpenes are responsible for the antiulcerogenic and antiinflammatory activities of C. sylvestris, which further enhances the medicinal use of this plant or its derivatives. However, the finding that clerodane diterpenes may suffer degradation in acid medium have raised doubts about the actual substances reached the receptors and carry out activity: diterpenes or their degradation products? In order to elucidate this issue, purified clerodane diterpenes casearin J (cas J) and O (cas O) were subjected to acid degradation in simulated gastric fluid without enzymes (PDA) alone and subsequently metabolized with S9 fraction (PDAME) liver enzymes. A direct metabolization of diterpenes with a S9 fraction (PME) was also performed. Respective remaining casearins were quantified in all the metabolizing products. In the end, macrophage stimulated by LPS in vitro assays of nitric oxide synthesis were conducted using as sample the purified cas J and O, PDA, PME and PDAME. Chromatographic (HPLC-PDA) and spectrometric techniques (UPLC-PDA-MS, 1H and and 13C NMR) were used for the structural determination of the generated derivatives. Ten substances were identified after the acid degradation of cas J (PDA-J), in addition to the remaining casearin (5.05%) and its epimer. Proposed structures of these compounds result of ester group hydrolysis in C-18 (PDA-J1), and in C-19 (PDA-J7), dialdehyde formation after diacetal C ring breaking (PDA-J2, majority), and additions in the aldehyde groups of the PDA-J2 of a water molecule (PDJ-3), one (PDA-J4 and PDA-J4.1) or two ethanol molecules (PDJ-5) and ester hydrolysis in C-7 of PDA-J2 (PDJ-6). Besides the remaining cas O (13.1%), nine compounds were identified after acid degradation. Their structures result of hydrolysis of the esterified groups in C-18 and C-19 (PDA-O1), dialdehyde formation after C-ring rupture (PDA-O2, majority), additions in the PDA-O2 aldehyde groups of one (PDA-O3 and PDA -O3.1) or two ethanol molecules (PDA-O4) and ester hydrolysis at C-6 (PDA-O5). Metabolization of casearin J by the S9 fraction generated two substances corresponding to the breakdown of n-butanoate in C-18 (PME-J1) and formation of cas J epimer (PME-J2), remaining 36.8% intact. In relation to the metabolization of casearin O, 36.5% remained intact and one molecule was formed after breaking the esterified substituents in C-6 and C-7 (PME-O1) and the other after the formation of dialdehyde at C ring (PME-O2). The analyzes indicated that the enzymatic metabolism of the PDA resulted in the same substances. In vitro LPS stimulated macrophage assays have shown that PDA and PME do not have in vitro anti-inflammatory activity of NO inhibition, as well as intact J and O casearins. / CNPq: 130329/2015-0