Biota des Kohlenstoffkreislaufs spielen bei der Speicherung und Verteilung des Kohlen-stoffs im Bodennahrungsnetz eine herausragende Rolle. Wobei der Abbau organischer Bodensubstanz stark von deren Verfügbarkeit für Mikroorganismen und Enzyme abhängt. Rhizosphäre und Detritusphäre verfügen über außerordentlich große Mengen an organischem Kohlenstoff. Dies macht diese Biosphären zu Hot-Spots mikrobieller Aktivität. Während der letzten Jahrzehnte stieg das Interesse an der Forschung zu mikrobieller Aktivität im Boden. Dennoch herrscht noch immer kein umfassendes Verständinis von Indikatoren und Triebkräften mikrobieller Aktivität in der Rhizosphäre und Detritusphäre. Dies ist nicht zuletzt der Tatsache geschuldet, dass es mehr als einer einzigen Methode zur Bestimmung dieser Faktoren bedarf. Aus diesem Grund setzt sich diese Arbeit zum Ziel, die mikrobielle Aktivität, ihre Indikatoren und Treiber zu explorieren. Folglich wurden diverse Indikatoren mikrobieller Aktivität, wie mikrobielle Respiration, mikrobielle Biomasse und Enzymkinetik, an Proben aus einem Feldexperiment mit diffe-rierendem Substrat-Eintrag (Mais-Rhizodeposite vs. Mais-Streu) ermittelt. Tiefengradienten der Indikatoren mikrobieller Aktivität dienten der Beurteilung der Auswirkungen sinkender Substratqualität und -quantität in Rhizo- und Detritusphäre mit zunehmender Bodentiefe. Besonderer Fokus lag dabei auf den Indizes unterschiedlicher Enzyme und deren Aktivität (z. B. spezifische Aktivität, katalytische Effizienz und Verhältnisse zwischen Enzymen des Kohlenstoff- und Stickstoff-Kreislaufs) im Tiefenprofil des Bodens. Neben dieser Feldstudie wurde das Verhältinis von RNA zu dsDNA als Indikator mikrobieller Aktivität entlang eines klimatischen Grandienten ermittelt, um den metabolischen Status innerhalb unterschiedlicher Bodentypen zu bestimmen. Die Feldstudien wurden um Experimente in Labor und Gewächshaus ergänzt, in denen mittels Isoto-penmarkierungsverfahren die Effekte von Wurzelhaaren und Protisten auf die mikrobielle Aktivität beleuchtet wurden. Diese Methode ermöglichte ein Nachvollziehen des C- und N-Flusses und trug damit zum Verständnis der Verflechtungen der Organismen im terrestrischen Boden-Nahrungsnetz bei. Die räumliche Verteilung der Enzymaktivität in der Rhizosphäre wurde anhand der Boden-Zymographie in situ untersucht. Durch unterschiedliche Substratverfügbarkeit wurde ein Wandel der funktionellen Eigenschaften der Mikroorganismengemeinschaften und des enzymatischen Systems induziert. Speziell der durchwurzelte Oberbodenhorizont zeigte einen Anstieg der mikro-biellen Aktivität im Vergleich zum Boden mit Streueintrag und der Kontrolle. Rhizodeposite sind eine grundlegende Kohlenstoff- und Energiequelle für Bodenmikroorganismen und stimulieren deren Wachstum und Aktivität. Die Präsenz von Rhizodepositen in Hot-Spots macht diese zu bevorzugten Habitaten für Mikroorganismen. Die Mehrzahl der Indikatoren für mikrobielle Aktivität wurde ausschließlich im Oberboden durch den Substrateintrag beeinflusst. Darunter auch die katalytische Effizienz, die – ungeachtet des Substrateintrags – von Oberboden (< 40 cm) zu Unterboden (> 40 cm) um das 2- bis 20-fache abnahm. Dies ließ auf die Relevanz der mit der Tiefe abnehmenden Menge und Qualität der Substrate im Boden als einflussnehmenden Faktor auf die mikrobielle Aktivität schließen. Das Verhältnis von RNA zu dsDNA spiegelte den metabolischen Status der mikrobiellen Organismengesellschaften in den meisten der beprobten Böden wider. Wohingegen das RNA:dsDNA Verhältnis dieser Indikatoreigenschaft widersprach, lagen erhöhte Tongehalte vor, die nach der Extraktion zu Ungenauigkeiten bei der Bestimmung der RNA-Quantität führten. Protozoen wird beim Vorgang des Kohlenstoffflusses von Bakterien zu Organismen höherer Trophieebenen eine bedeutende Rolle zugesprochen, was ebenfalls ihren Einfluss auf die mikrobielle Aktivität im Boden unterstreicht. Um diesen Effekten, im Speziellen jenen der Acanthoamoebe auf den Kohlenstoff- und Stickstofffluss, sowie die Indikatoren mikrobieller Aktivität in der Rhizo- und Detritusphäre nachzugehen, wurde ein dreifaches Isotopenmarkierungs-Experiment durchgeführt. Es ergab, dass Kohlenstoffflüsse und Enzymaktivitäten sowohl von Substrateintrag als auch Substratqualität in Rhizo- wie Detritusphäre sowie deren faunistischer Besiedlung abhängen. Daraus erschloss sich, dass die Besiedlung mit Acanthamoeben als potenzielle Triebkraft mikrobieller Aktivität, besonders innerhalb der Rhizosphäre, gedeutet werden kann. Um den Einfluss von Wurzelhaaren auf die mikrobielle Aktivität und den Priming Effekt in der Rhizosphäre einzuschätzen, wurde ein Experiment im Gewächshaus mit kontinuierlicher Markierung von Boden mit Pflanzenbewuchs und einer Kontrolle ohne Bewuchs mit 13C-Isotopen durchgeführt. Wurzelhaare zeigten sich darin als Initiatoren eines positiven Rhizosphären-Priming Effektes während der Wachstumsphase, wohingegen der Abbau organischer Bodensubstanz in den Kontrollen gehemmt war. Im Falle der positiven Initialwirkung der Wurzelhaare stiegen zudem die Enzymaktivitäten von Chitinase und ß-Xylosidase an, was auf eine Zersetzung stabiler, organischer Bodensubstanz hinwies. Damit konnte ein deutlicher Effekt von Wurzelhaaren auf die mikrobielle Aktivität im Boden während der Phase des Pflanzenwachtums nachgewiesen werden. Somit vermittelt diese Arbeit ein weiterführendes Verständnis der auf mikrobielle Aktivität im Boden einwirkenden Faktoren und stellt eine Auswahl von Indikatoren zur Charakterisierung dieser Aktivität vor, die sowohl auf der Landschaftsebene als auch in der prozessorientierten Forschung im Wurzelraum Anwendung finden kann.

In this thesis Raman spectroscopy is evaluated as a tool of identification and discrimination of carotenoids from microbial biomass. Microorganisms, halophilic or nonhalophilic, belong to Cyanobacteria, Proteobacteria, Chlorophyta, Rhodophyta and to others. Biomass was cultiveted under laboratory conditions and yielded varied colours. Raman spectra were recorded succesfully from lyophilized biomass by excitation wavelenth 514.5 nm (dispersive Raman microspectrometr) and 1064 nm (FT Raman spectrometer). Results were compared with Raman spectroscopic data from pigment extracts. Spectra of carotenoids are characterized by the main Raman bands υ1, υ2 a υ3 due to C=C stretching, C-C stretching and C-CH3 deformation. HPLC/UV-VIS allows effective pigment separation from extracts and detection of separated pigments by UV-VIS analyzator. Assessment of Raman analysis and its potential to detect microbial carotenoids are discused. Sarcinaxantin is an unusual carotenoid identified together with more common β - carotene. Raman spectroscopic results obtained on carotenoids recorded from colonies which accumulated more than one carotenoid need to be interpreted carefully. Powered by TCPDF (www.tcpdf.org)

Thesis (MTech (Environmental Management))--Cape Peninsula University of Technology, 2015. / This study was conducted to investigate the occurrence of PAH degrading microorganisms in two river systems in the Western Cape, South Africa, and their ability to degrade two PAH compounds (acenaphthene and fluorene). A total of 19 bacterial isolates were obtained from the Diep- and Plankenburg Rivers. These microorganisms were first identified phenotypically on various selective and general media (such as nutrient agar, Eosine Methylene Blue and Mannitol Salts Agar), followed by staining and biochemical testing, followed by molecular identification using 16S rRNA and PCR. The isolates were then tested for acenaphthene and fluorene degradation first at flask scale and then in a Stirred Tank Bioreactor at varying temperatures (25ºC, 30ºC, 35ºC, 37ºC, 38ºC, 40ºC and 45ºC). All experiments were run without the addition of supplements, bulking agents, biosurfactants or any other form of biostimulants. Four of the 19 isolated microorganisms were identified as acenaphthene and fluorene degrading isolates. Three of the four microorganisms identified as PAH degrading isolates were Gram negative isolates. Results showed that Raoultella ornithinolytica, Serratia marcescens, Bacillus megaterium and Aeromonas hydrophila efficiently degraded fluorene (99.90%, 97.90%, 98.40% and 99.50%) and acenaphthene (98.60%, 95.70%, 90.20% and 99.90%) at 37ºC, 37ºC, 30ºC and 35ºC, respectively. The degradation of fluorene was found to be more efficient and rapid compared to that of acenaphthene and degradation at Stirred Tank Bioreactor scale was more efficient for all treatments. Throughout the biodegradation experiments, there was an exponential increase in microbial plate counts ranging from 5 x 104 to 9 x 108 CFU/ml. The increase in plate count was observed to correlate with the efficient degradation temperature profiles and percentages. The PAH degrading microorganisms isolated during this study significantly reduced the concentrations of acenaphthene and fluorene and can be used on a larger, commercial scale to bioremediate PAH contaminated river systems. Other factors that influence the optimal expression of biodegradative potential of microorganisms other than temperature and substrate (nutrient) availability, such as pH, moisture and salinity will be investigated in future studies, as well as the factors contributing to the higher fluorene degradation compared to acenaphthene. Furthermore, the structure and toxicity of the by-products and intermediates produced during microbial metabolism of acenaphthene and fluorene should be investigated in further studies.

MSc., Faculty of Science, University of the Witwatersrand, 2011 / The increasing emergence of drug-resistant pathogens poses a major threat to public health. Although influenced by multiple factors, resistance is often associated with mutations in drug target-encoding or associated genes. The potential fitness cost of such resistance mutations is, in turn, a key determinant of the spread of drug-resistant strains. Rifampicin (RIF) is a frontline anti-tuberculosis agent that targets the rpoB-encoded β-subunit of the DNA-dependent RNA polymerase (RNAP). RIF resistance (RIFR) maps primarily to mutations in rpoB that might be expected to affect transcription and so the ability of the organism to cause disease. Accordingly, numerous studies have assessed the impact of RIFR on key fitness indicators in pathogens including Mycobacterium tuberculosis (MTB). In contrast, the specific consequences of RIFR for bacterial physiology remain poorly understood. Notably, previous studies of the effects of RIFR-associated rpoB mutations on mycobacterial physiology have been conducted using strains generated by RIF exposure, without accounting for the potential impact of second-site mutations that may compensate for fitness costs or contribute to drug resistance. In this study, site-directed mutagenesis and allelic exchange were employed to generate a panel of M. smegmatis (MSM) strains containing clinically-relevant RIFR-associated point mutations. Importantly, this methodology enables the introduction of rpoB mutations into defined strain backgrounds in the complete absence of RIF. Using this approach, we constructed “RIF naive” MSM rpoB mutant strains carrying either an S531L or H526Y mutation. The resulting mutants were 100-fold less susceptible to RIF than the isogenic, parental strain. Notably, the inclusion of selected efflux inhibitors in susceptibility assays had little impact on mutant susceptibility to RIF. In contrast, restoration of the wild-type allele returned the observed susceptibility to parental levels, thereby providing strong evidence of the sufficiency of a single rpoB mutation for clinical RIFR in mycobacteria. Competitive growth assays utilizing the S531L mutant and the parental strain exposed a growth defect for the S531L mutant. However, discriminating between wild-type and mutant rpoB strains proved a significant technical challenge, again highlighting the difficulties associated with inferring in vivo fitness from in vitro assays conducted under a limited number of different conditions. In summary, our results suggest the benefit of a deeper exploration of the physiological and fitness implications of RIFR-associated mutations. In addition, in coupling a system which enables an evaluation of the physiological consequences of drug resistance-associated mutations with evolutionary analyses, we provide preliminary evidence of the benefits of a multipronged approach to elucidating the physiological implications of drug resistance in MTB.

Les biotechnologies basées sur des microorganismes capables de survivre à de fortes doses de rayonnement ionisants et de concentrer les radionucléides constituent une technique attractive pour décontaminer les effluents nucléaires, en particulier du fait du faible volume de déchets générés. En utilisant deux méthodes d’analyses directes et complémentaires que sont la métagénétique et la métaprotéomique, l’inventaire complet de la piscine de refroidissement d’un coeur de réacteur nucléaire (en fonctionnement et à l’arrêt) et d’une piscine de stockage de sources radioactives de cobalt a été réalisé. Les microbiotes sont extrêmement différents entre les deux piscines. Une majorité de Cyanobacteria a été identifiée dans la piscine du réacteur alors qu’une majorité de Proteobacteria l’a été dans la piscine des sources. Durant le fonctionnement du réacteur, une majorité de Variovorax a été identifiée. Certaines espèces de Variovorax sont capables d’utiliser du H2 comme source d’énergie, ce qui peut leur donner un avantage dans un environnement nucléaire aquatique. Parmi les microorganismes isolés de la piscine du réacteur, 46 bactéries ont été identifiées. Leur capacité à résister aux rayonnements gamma et à accumuler l’uranium et le cobalt ont été déterminées. Parmi ces bactéries, six souches ont été capables d’accumuler la totalité de l’uranium d’une solution à 5 μM, et deux d’entre elles ont entièrement accumulé l’uranium d’une solution à 50 μM. Ce travail présente le premier inventaire complet d’une piscine de refroidissement d’un coeur de réacteur nucléaire en fonctionnement. Cette thèse présente des perspectives tant sur le plan industriel avec l’utilisation des microorganismes isolés dans un procédé de biodécontamination d’effluents nucléaires que sur le plan fondamental avec l’élucidation des mécanismes développés par ces microorganismes pour résister aux rayonnements et accumuler les radionucléides. / Biotechnology with microorganisms able to survive high radiation doses and concentrate radionuclides is an attractive technology to decontaminate nuclear effluents with low waste volume. By using two direct and complementary analysis methods, metagenetics and metaproteomics, the complete inventories of microorganisms present in a French nuclear reactor cooling pool (during operation and at shutdown) and in a radioactive 60Co sources storage pool have been performed. The microbiota from the two pools were extremely different, with a majority of Cyanobacteria in the sources storage pool, and Proteobacteria in the reactor pool. Depending on the pools’ conditions a change in the microbiota had been observed. Variovorax was the main genus identified during the reactor’s operation. Some strains of Variovorax are able to use H2 as an energy source, conferring them an advantage in nuclear pools. Several microorganisms have been isolated from the reactor pool. Among them 46 bacteria were identified. Their abilities to resist ionizing radiations and to accumulate specific radionuclides were determined. Several genera studied in this work had never been described concerning their ability to resist radiations or accumulate radionuclides. Six strains could entirely remove uranium from a 5 μM solution and up to 50 μM for two strains. This work presents the first complete inventory of a working nuclear reactor cooling pool. This PhD work opens interesting industrial perspectives as the isolated strains could be implemented in a new nuclear effluents decontamination process and fundamental perspectives as their resistance and radionuclides accumulation pathways could be deciphered.

Poucos estudos existem sobre o efeito de diferentes inóculos microbianos na produção de composto fermentado bokashi e seu efeito no solo em relação à disponibilidade de nitrogênio e fósforo. A farinha de penas é outro potencial adubo orgânico que é pouco explorado no Brasil. O presente estudo teve por objetivo avaliar o efeito dos inóculos microbianos comercial e nativo, assim como da farinha de penas, na disponibilização de nitrogênio e fósforo, e sua interferência na nitrificação no solo. Os compostos bokashi foram feitos um com inóculo coletado em solo de área de preservação permanente misturado a solo de área de cultivo e outro com inóculo comercial. Os tratamentos: bokashi com inóculo comercial (BC), bokashi com inóculo nativo (BN), mistura de farelos com inóculo comercial (FC), mistura de farelos com inóculo nativo (FN), somente mistura de farelos (F), somente aplicação do inóculo comercial no solo (TC), farinha de penas (FP) e somente solo (T) foram misturados ao solo e incubados por 84 dias. Avaliações periódicas foram feitas dentro do período de incubação, as quais mensuraram a mineralização de nitrogênio, a nitrificação, a disponibilização de fósforo, a respiração basal, o carbono da biomassa microbiana, o coeficiente metabólico, o pH e o carbono e o nitrogênio total. O nitrogênio e o fósforo disponível foram avaliados nos compostos. O bokashi foi eficiente na disponibilização de fósforo no solo, assim como nitrogênio e fósforo no composto. A mineralização de nitrogênio foi reduzida quando os farelos passaram pelo processo de bokashi. A aplicação do bokashi não interferiu na nitrificação. O BC foi mais eficiente em disponibilizar fósforo e nitrogênio no composto e no solo que o BN. O FC apresentou uma atividade biológica de decomposição mais intensa, assim como maior mineralização de nitrogênio dos compostos quando comparado ao FN. O FN aumentou o nitrogênio orgânico no solo. Ambos inóculos demonstraram pouco efeito na nitrificação e na acidez do solo. A aplicação do FP no solo apresentou grande potencial para o suprimento de nitrogênio. / There is a reduced amount of studies on the different microbial inoculum effects in bokashi fermented compost and its effects related to soil nitrogen and phosphorus availability. The poultry feather manure is another potential fertilizer with little exploration in Brazil. The present study aim to evaluate the microbial inoculum effects, commercial and native, and the poultry feather manure, in soil nitrogen and phosphorus availability and nitrification interference. The bokashi composts were made one with collected inoculum in permanent preservation area mixed with crop soil and another with commercial inoculum. The treatments: commercial inoculum bokashi (BC), native inoculum bokashi (BN), commercial inoculum bran mixture (FC), native inoculum bran mixture (FN), bran mixture (F), just commercial inoculum in soil (TC), poultry feather manure (FP) and just soil (T) were mixed with a soil and incubated for 84 days. Periodic evaluations were made in incubation period, that one has assessed the nitrogen mineralization, the nitrification, the phosphorus availability, the basal respiration, the microbial biomass carbon, the metabolic coefficient, the pH and the total carbon and nitrogen. The nitrogen and phosphorus availability was evaluated in composts. The bokashi was efficient in soil phosphorus availability, like nitrogen and phosphorus in compost. The nitrogen mineralization was reduced with bokashi application. The bokashi application did not interfered in nitrification. The BC was more efficient in phosphorus and nitrogen availability in compost and in soil then the native inoculum bokashi. The FC show more biological decomposition activity, therefore with more nitrogen mineralization in relationship with FN. The FN increased the soil organic nitrogen. Both inoculum revealed little effect in nitrification and soil acidity. The FP application in soil demonstrated great potential in nitrogen supply.

Este estudo consistiu na investigação sobre a interação dos lubrificantes empregados na usinagem de metais com a matéria orgânica natural (substâncias húmicas), a sua mobilidade no solo, a degradação microbiológica e a remoção dos mesmos do solo. Realizou-se, também, um estudo sobre as mudanças nas características dos fluidos após a sua utilização. Para o processo de degradação das amostras de fluido, submetidos aos efeitos de diferentes fatores ambientais, foram utilizados quatro tratamentos : (i) microrganismos nativos, chamada amostra controle; (ii) amostra controle com matéria orgânica proveniente de turfa; (iii) amostra controle acrescida de microrganismos existentes nos efluentes de máquinas de corte; e (iv) amostra controle com adição de microrganismos de compostagem. Para a pesquisa da degradação sem o efeito dos parâmetros climáticos, foram utilizadas amostras de solo contaminadas mantendo-se em estufa, e a inoculação dos microrganismos em meios de cultura com e sem acréscimo de fonte alternativa de carbono. Como técnicas analíticas, foram utilizadas a CG-DIC e a CG-EM. Essas técnicas são indicadas tanto para estudar a composição dos fluidos quanto dos produtos de degradação microbiológica, tendo sido otimizados métodos analíticos para serem empregados no monitoramento ambiental e de estudos de degradação. As análises por IVTF e por EF também foram empregadas na identificação e quantificação dos fluidos. Observou-se uma considerável interação dos fluidos solúveis com a matéria orgânica do solo, embora tenham se apresentado com alta mobilidade para alguns constituintes, bem como um acelerado processo de degradação durante o uso. De outro modo, os fluidos insolúveis se apresentaram mais imóveis, ficando retidos na matéria orgânica do solo, entretanto, foram mais prontamente degradados no ambiente que os solúveis. A adição de matéria orgânica e de microrganismos de compostagem acelerou o processo de degradação para todos os fluidos de corte investigados. / This study is an investigation of the interaction of lubricants employed in metal machining and natural organic matter (humic substances), their mobility in soil, microbial degradation and their removal from the soil. Also, was performed study of changes in characteristic on fluids after their use. On degradation process from fluid samples, contaminated soils submitted to different environment factors, were used four treatments : (i) native microorganisms named control sample; (ii) control sample added by organic matter from peat; (iii) control sample added by microorganisms existing in flowing out from cutting machines; and (iv) control sample with addition of microorganisms from composting. For degradation research by no effect from climate parameters were used sample of contaminated soil been investigated in stove and microorganisms inoculation in culture mean with and without addition of alternative carbon source. As analytical techniques were used GC-FID and GG-MS. These techniques are both indicated for fluid composition studies and microbial degradation product. Analytic methods had been optimized to be employed on environmental monitoring and degradation studies. The FTIR and espectrofluorimetric methods were used for the fluid identification and quantification. Were observed a notable interaction between soluble fluids and soil organic matter, thought it had been verified high mobility for some compounds as well an accelerated process of degradation during their use. Otherwise, insoluble fluids were more immobile been restrained in soil organic matter, nevertheless, were readily degraded in environment than soluble ones. Organic matter and composting microorganisms\' addition accelerated the degradation process for all cutting fluids investigated.

Vibrio bacteria are emerging pathogens responsible for 80,000 illnesses and 100 deaths in the United States each year. Infections are directly linked to the marine environment and are acquired by consuming contaminated seafood or exposing wounds during aquatic activities. Florida has the highest national incidence of vibriosis, with 20% of its cases reported from the Indian River Lagoon region, a popular recreation destination. This study utilized a combination of cultivation and molecular techniques to investigate the local distribution of V. vulnificus, V. parahaemolyticus and V. cholerae in this local waterway. The targeted species were found in an array of samples which may facilitate their transmission to humans. Overall, these bacteria were abundant in estuarine sediments (Vp: 2,439 CFU/g, Vv: 303 CFU/g, Vc: 176 CFU/g), on the sharp edges of oyster shells (Vp: 82 CFU/cm, Vv: 102 CFU/cm, Vc: 41 CFU/cm), and in the water column (Vp: 3.78 CFU/ml, Vv: 5.51 CFU/ml, Vc: 2.46 CFU/ml). Vibrio also pose a hazard to recreational anglers as they were recovered from fish (Vp: 61%, Vv: 55%, Vc: 30%), live bait shrimp (Vp: 80%, Vv: 37%, Vc: 0%) and hooks (Vp: 32%, Vv: 18%, Vc: 0%). Additionally, a molecular analysis of the V. vulnificus virulence revealed that the local population was dominated by disease-causing (vcgC) strains, which may explain why wound-related infections are common in this region. Vibrio occurrence varied both spatially and temporally due to their relationship with salinity and temperature. These bacteria exhibited a strong negative correlation with salinity, being particularly abundant near freshwater discharge locations. Due to Florida’s year-round warm climate, these species were found to be permanent members of the local microbial community. Seasonal peaks in abundance occurred between August and October, a period which corresponds with the warmest water temperatures as well as frequent rainfall. Predictive models were constructed based on these parameters to provide a better understanding of how, when and where Vibrio spp. may be encountered by humans. This information is important for both water management and healthcare initiatives, with an overall goal of improving local recreational safety. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Manguezais são ecossistemas costeiros que ocorrem na transição entre os ambientes terrestres e marinhos, ao longo das regiões tropicais e subtropicais, sofrendo influência direta do regime das marés. A comunidade microbiana diversificada é fundamental para a ocorrência da ciclagem de nutrientes e, portanto, manutenção da biodiversidade faunística e florística nestes ambientes. As actinobactérias correspondem um grupo heterogêneo de bactérias filamentosas, que naturalmente habitam o solo, adaptam-se às diversas condições do ambiente, produzem antibióticos e são capazes de colonizar a rizosfera e tecidos internos das plantas. Neste trabalho foi possível observar a diversidade de actinobactérias rizosféricas isoladas nos manguezais de Cananéia e Bertioga SP; avaliar a produção de metabólitos secundários antifúngicos desses microrganismos; analisar o perfil químico dos extratos orgânicos das actinobactérias por espectrômetro de massas, seguidos de avaliação dos constituintes químicos desses extratos por cromatografia em camada delgada e coluna preparativa para separação dos mesmos, onde após os bioensaios com as frações ativas, foi determinado a concentração inibitória mínima dessas frações. / Mangroves are coastal ecosystems which occur in the areas of transition between marine and terrestrial environments throughout the tropical and subtropical regions, suffering direct tide influence. The diverse microbial communities are important to the nutrient cycling occurrence and consequently to the maintenance of these environments fauna and flora biodiversity. The Actinobacteria are a heterogeneous group of filamentous bacteria that naturally inhabit the soil. They can easily adapt to different environmental conditions, producing antibiotics and colonizing the rhizosphere and plants internal tissues. This study aims were: to allow the assessment of the diversity of the diversity of rhizosphere Actinobacteria isolated from mangroves located in Cananeia and Bertioga, cities under the jurisdiction of Sao Paulo State; to evaluate the production of antifungal secondary metabolites of these microorganisms; to analyze the chemical profile of organic extracts of Actionobacteria by mass spectrometry, followed by the evaluation of the chemical components of theses extracts through thin-layer chromatography and preparative column for their separation. After this process minimum inhibitory concentration of the active fractions of the bioassays were determined.

A study to assess the potentials of some commensal bacteria that belong to Staphylococcus, Acinetobacter and Stenotrophomonas genera as reservoirs of antibiotic resistance determinants in the environment of Nkonkobe Municipality of the Eastern Cape Province, South Africa, was carried out using standard microbiological and molecular techniques. A total of 120 Staphylococcus isolates which consisted of Staphylococcus haemolyticus (30%), Staphylococcus aureus (23.3%) from pig; Staphylococcus capitis (15%) from goat; Staphylococcus heamolyticus (5%) and Staphylococcus xylosus (15%) from cattle and other Staphylococci (11%) from dead chicken and pigs were isolated. About 23.3% of these isolates were coagulase positive and 76.7% were coagulase negative. This difference in prevalence along coagulase production divide was statistically significant (p < 0.05). Eighty-six Acinetobacter species (Acinetobacter baumannii/calcoaceticus and Acinetobacter haemolyticus) were also isolated from Alice and Fort Beaufort towns samples, while 125 Stenotrophomonas maltophilia isolates were from grass root rhizosphere (96%) and soil butternut root rhizosphere (4%). Between 75-100% of the Staphylococccus species were resistant to Penicillin G, tetracycline, sulphamethaxole and nalidixic acid; about 38 % were methicillin resistant, consisting of 12.6% methicillin resistant Staphylococcus aureus (MRSA) from pig and a total of 12% vancomycin resistant were observed. Also, 12% of the isolates were erythromycin resistant while 40.2 % were resistant to the third generation cephalosporin, ceftazidime. The antibiotic resistance genes vanA, VanB, eryA, eryB, eryC were not detected in all the phenotypically resistant Staphylococccus species, but mec A gene and mph genes were detected. In the Acinetobacter species, a wide range of 30-100% resistance to penicillin G, ceftriazone, nitrofurantoin, erythromycin, and augmentin was observed. Polymerase chain reaction (PCR) revealed the presence of Tet(B) and Tet(39) genes in these species, while Tet (A), Tet(M) and Tet(H) were absent. Also, 9.3% of the Acinetobacter species showed phenotypic production of extended spectrum beta lactamases (ESBLs) while 3.5% were positive for the presence of blaCTX-M-1 genes. The Stenotrophomonas maltophilia isolates showed varying resistance to meropenem (8.9%), cefuroxime (95.6 %), ampicillin-sulbactam (53.9%), ceftazidime (10.7%), cefepime (29.3 %), minocycline (2.2%), kanamycin (56.9%), ofloxacin (2.9%), levofloxacin (1.3%), moxifloxacin (2.8%), ciprofloxacin (24.3%), gatifloxacin (1.3%), polymyxin B (2.9 %), cotrimoxazole (26.1%), trimethoprim (98.6%), aztreonam(58%) and Polymyxin B (2.9 %). The isolates exhibited significant susceptibility to the fluoroquinolones (74.3-94.7 %), polymycin (97.1%) and meropenem (88.1%). Only sul3 genes were the only sulphonamide resistance gene detected among the trimethoprim-sulphamethoxazole resistant isolates. The observed multiple antibiotic resistance indeces (MARI) of >2 for Staphylococcus species, Acinetobacter species and Stenotrophomonas maltophilia suggest that they have arisen from high-risk sources where antibiotics are in constant arbitrary use resulting in high selective pressure. The presence of tetracycline resistance genes in Acinetobacter species justifies the observed phenotypic resistance to oxytetracycline and intermediate resistance to minocycline. High phenotypic resistance and the presence of some resistance genes in Staphylococcus species is a possible threat to public health and suggests animals to be important reservoirs of antibiotic resistance determinants in the environment. Indiscriminate use of antibiotics induces this kind of antibiotic resistance and should be discouraged. Personal hygiene is encouraged as it reduces the load of Acinetobacter species contacted from the environment that may be difficult to control. Commensal Stenotrophomonas maltophilia are as important as their clinical counterparts due to their roles in opportunistic infection, antibiotic resistance and their associated genes, especially sul gene. Personal hygiene is hereby advocated especially when in contact with soil, plants and plants’ rhizospheric soil