101.
The Effects of Nutrient Type and Stoichiometry on Bacterial Community Composition in Streams and Wetlands
- Barlett, Melissa Ann
Nitrogen and phosphorus additions from various sources can change our aquatic systems, both through increased nutrient concentrations and changes in nutrient stoichiometry. Because bacteria are important in the cycling of nutrients and aquatic food webs, understanding how stoichiometry affects the bacterial community enhances our understanding of how these changes potentially affect aquatic ecosystems as a whole. This study examined the interactions between N:P ratios and sources and bacterial communities. To examine these interactions, a variety of methods were used. A field study was conducted at three sites along the Mahoning River. Both microcosm studies in the lab and mesocosm studies...
102.
Modelling rhizosphere interactions of Burkholderia species
- Levy, Avram
[Truncated abstract] Genus Burkholderia encompasses a diverse collection of bacteria that inhabit rhizospheres throughout the world. Species can provide beneficial returns for eukaryotes, such as nitrogen fixation and nodule formation in plants and biocontrol of cropping systems. Burkholderia members can also cause disease in various animals, fungi and plants. These seemingly conflicting characteristics point to the capacity of Burkholderia spp. to interact with diverse eukaryotes. Within terrestrial ecosystems, Burkholderia spp. must negotiate favourable outcomes with both the primary producers and the primary decomposers, namely plants and fungi. It is these ongoing negotiations which govern many rhizosphere processes and lead to...
103.
Secondary metabolites from marine microorganisms
- KELECOM,ALPHONSE
After 40 years of intensive research, chemistry of marine natural products has become a mature field. Since 1995, there are signals of decreased interest in the search of new metabolites from traditional sources such as macroalgae and octocorals, and the number of annual reports on marine sponges stabilized. On the contrary, metabolites from microorganisms is a rapidly growing field, due, at least in part, to the suspicion that a number of metabolites obtained from algae and invertebrates may be produced by associated microorganisms. Studies are concerned with bacteria and fungi, isolated from seawater, sediments, algae, fish and mainly from marine...
104.
Bacterial transit in the digestive tract of rainbow trout.
- LESEL, R; FAUCONNEAU, B; ALZIEU, P
The present study concerns bacterial transit in the digestive tract of rainbow trout at 13 degree C and compares fecal excretion of 4 tracers in the alimentary bolus, an inert bacterial tracer: spores of Bacillus stearothermophilus , a bacterial marker capable of multiplying in the digestive organs: Citrobacter freundii ; a tracer of the liquid phase: polyethylene glycol (PEG), a tracer of the solid phase: Cr sub(2)O sub(3). Two peaks of fecal excretion of bacterial bodies are indicated in the results, the first one taking place within the first 4 h following ingestion of the traced meal, the second peak,...
105.
Estudo do efeito adjuvante de CTB em fusões com as proteínas pneumocócicas PsaA e PspA no desenvolvimento de vacinas protéicas contra Streptococcus pneumoniae
- Ana Paula de Mattos Arêas
A colonização da mucosa respiratória é a primeira etapa na patogênese de Streptococcus pneumoniae, bactéria causadora de pneumonia, meningite, e otite média, responsável por mais de um milhão de mortes por ano no mundo. As proteínas de superfície PsaA e PspA têm sido investigadas como candidatos vacinais para estas doenças. CTB é a porção não tóxica da toxina colérica (CT), responsável pela ligação da toxina ao receptor celular GM1 e descrita como adjuvante de mucosas. Neste trabalho, estes genes de S. pneumoniae foram clonados em pAE, um vetor de expressão de E. coli, que utiliza o promotor T7, ou a...
106.
Sobrevivência de Escherichia coli,Staphylococcus aureus e Salmonella Enteritidis durante o armazenamento de hambúrguer de frango
- Casarin, Letícia Sopeña
Com o objetivo de avaliar a sobrevivência ao congelamento de microrganismos potencialmente patogênicos, hambúrgueres de frango foram contaminados com Escherichia coli (ECHC), Staphylococcus aureus (SAFH) e Salmonella Enteritidis (SE86) e armazenados a -18ºC. Os mesmos microrganismos e ainda E. coli ATCC 25972, S. aureus ATCC 25923, and S. Enteritidis ATCC 13076 também foram inoculados em água peptonada 0,1% e congelados a -18ºC, a fim de avaliar um possível efeito protetor dos componentes do hambúrguer sobre os microrganismos. A quantificação dos microrganismos foi realizada nos intervalos de 0, 1, 2, 3, 4, 7, 14, 21 e 28 dias de congelamento. Com...
107.
Estudo de bacteriocinas produzidas por espécies de Enterococcus
- Ferreira, Alessandra Einsfeld
As enterocinas são compostos de natureza protéica que apresentam atividade antimicrobiana contra bactérias patogênicas e deteriorantes de alimentos. Por esta razão, nos últimos anos, o interesse por estas substâncias tem aumentado devido ao seu uso potencial como biopreservante de alimentos. Realizando uma triagem com 352 cepas de Enterococcus spp para detectar atividade antimicrobiana, foram encontradas 18 cepas (5%) produtoras de enterocinas, pertencentes às espécies E. faecalis, E. faecium e E. mundtii todas provenientes de amostras de fezes de humanos. Destas cepas foram produzidos sobrenadantes livres de células e realizados testes para caracterização das enterocinas produzidas. As enterocinas produzidas pelas 18...
108.
Isolamento e caracterização genética de Listeria sp. proveniente de hortaliças folhosas minimamente processadas comercializadas em Porto Alegre - RS
- Verdin, Sylvia Elisa Frizzo
Hortaliças minimamente processadas passam por etapas como: lavagem, seleção, descasque, corte e sanificação e, depois de embaladas, são armazenadas sob refrigeração. No entanto, se não houver cuidado na procedência da matéria-prima, no processamento e na higienização, há o risco de se encontrar bactérias patogênicas, entre elas Listeria monocytogenes, a qual pode crescer à temperatura de refrigeração. A listeriose manifesta-se como um resfriado, podendo progredir para meningite, meningoencefalite, septicemia e aborto. Este trabalho teve por objetivo verificar a ocorrência de Listeria sp. Em hortaliças folhosas minimamente processadas comercializadas em Porto Alegre RS e verificar a relação genética entre os isolados....
109.
Infectious Coryza: Overview of the Disease and New Diagnostic Options
- Blackall, P.J.
Infectious coryza is a well-recognized and commonly encountered upper respiratory tract disease of chickens that is caused by the bacterium Haemophilus paragallinarum. The occurrence of recent outbreaks in North America has emphasized that the disease can be significant in meat chickens as well as layer chickens. In developing countries, coryza is commonly complicated by the presence of a range of other infections, resulting in severe disease and significant economic losses. Unusual forms of the disease, involving arthritis and septicemia, again associated with the presence of other pathogens, have been found in South America. Newly recognized bacteria such as Ornithobacterium rhinotracheale...
110.
Infectious Coryza: Overview of the Disease and New Diagnostic Options
- Blackall, P.J.
Infectious coryza is a well-recognized and commonly encountered upper respiratory tract disease of chickens that is caused by the bacterium Haemophilus paragallinarum. The occurrence of recent outbreaks in North America has emphasized that the disease can be significant in meat chickens as well as layer chickens. In developing countries, coryza is commonly complicated by the presence of a range of other infections, resulting in severe disease and significant economic losses. Unusual forms of the disease, involving arthritis and septicemia, again associated with the presence of other pathogens, have been found in South America. Newly recognized bacteria such as Ornithobacterium rhinotracheale...
111.
Infectious Coryza: Overview of the Disease and New Diagnostic Options
- Blackall, P.J.
Infectious coryza is a well-recognized and commonly encountered upper respiratory tract disease of chickens that is caused by the bacterium Haemophilus paragallinarum. The occurrence of recent outbreaks in North America has emphasized that the disease can be significant in meat chickens as well as layer chickens. In developing countries, coryza is commonly complicated by the presence of a range of other infections, resulting in severe disease and significant economic losses. Unusual forms of the disease, involving arthritis and septicemia, again associated with the presence of other pathogens, have been found in South America. Newly recognized bacteria such as Ornithobacterium rhinotracheale...
112.
Constituição físico-química, celular e microbiológica do leite de búfalas (Bubalus bubalis) criadas no Estado de São Paulo
- Paula Andréa de Santis Bastos
O presente estudo objetivou estabelecer o padrão de referência dos constituintes físico-químicos e celulares do leite e identificar relações entre os valores desses elementos constituintes da secreção láctea de búfalas, criadas em São Paulo/BR. Para tanto foram utilizadas 98 búfalas adultas e lactantes, da raça Murrah, distribuídas em vários grupos experimentais, segundo os seguintes fatores de variabilidade: idade; fase da lactação; momento da ordenha e tipo de ordenha utilizada. Dessas búfalas foram colhidas 1.176 amostras de leite (de glândulas mamárias que não apresentavam sinais de processo inflamatório ou tivessem sido submetidas a tratamento intramamário). As amostras de leite foram submetidas...
113.
Impact of the Phaeocystis globosa spring bloom on the intertidal benthic compartment in the eastern English Channel: A synthesis
- Spilmont, Nicolas; DENIS, Lucie; Artigas, Luis Felipe; Caloin, Frederic; Courcot, Lucie; Creach, Anne; DESROY, Nicolas; Gevaert, Francois; Hacquebart, Pascal; Hubas, Cedric; Janquin, Marie-Andree; Lemoine, Yves; Luczak, Christophe; Migne, Aline; Rauch, Mathieu; Davoult, Dominique
From 1999 to 2005, studies carried out in the frame of regional and national French programs aimed to determine whether the Phaeocystis globosa bloom affected the intertidal benthic communities of the French coast of the eastern English Channel in terms of composition and/or functioning. Study sites were chosen to cover most of the typical shore types encountered on this coast (a rocky shore, an exposed sandy beach and a small estuary). Both the presence of active Phaeocystis cells and their degradation product (foam) did have a significant impact on the studied shores. The primary production and growth rates of the...
114.
Dendritic cells and macrophages in the mammalian cornea : distribution, morphology, phenotype and their role in responding to microbial challenge
- Chinnery, Holly Rose
[Truncated abstract] The cornea plays a major role in the refraction of light and thus the maintenance of its transparency is critical for optimal vision. Infection or trauma can initiate a host inflammatory response, which can cause edema of the collagenous stroma. This tissue edema compromises vision by disrupting the regular arrangement of the corneal stromal lamellae, whose organization is critical to its refractive properties. Until recently, it was the accepted dogma that the cornea was an immune privileged tissue owing in part to its avascular nature and paucity of resident macrophages and dendritic cells (DCs) in the central region...
115.
Plasmid-associated phenathrene degradation by Chesapeake Bay sediment bacteria.
- OKPOKWASILI, G; SOMERVILLE, C; GRIMES, D; COLWELL, R
A differential, phenanthrene-enrichment agar plating technique was used to isolate phenanthrene-degrading bacteria from phenanthrene-enriched Chesapeake Bay sediment. One of the isolates, a yellow pigmented, slime-producing, Gram-negative rod identified as Flavobacterium sp. has been studied in detail. It has been found to carry a single plasmid with a mass of about 34 megadaltons. Results of hydrocarbon adherence tests showed that the organism adhered only minimally to n-octane and n-hexadecane, but emulsified cyclohexylbenzene and 1,2,3,4,-tetrahydronaphthalene (tetralin). Curing of the plasmid with 3 mu g/ml novobiocin resulted in loss of phenanthrene clearing ability. Ability to degrade phenanthrene was confirmed using super(14)C-labeled phenanthrene.
116.
Identificación de bacterias marinas cultivables de la ciudad costera Comodoro Rivadavia, Argentina
- Pucci Bissetta, Graciela Natalia; Acuña, Adrián Javier; Llanes, María L.; Tiedemann, Maria C.; Pucci Ceima, Oscar Héctor
This study identifies marine bacteria obtained
from three sites along Comodoro Rivadavia coast, south of
Argentina. Seawater and intertidal sediment samples were
collected. Two of the sites were located close to the city sewage
system (CR1, CR2) and the third one (CR3) was near from an
oil buoy. Bacterial counts were performed on four culture
media: BBR, BRN, mineral medium with crude oil and gas oil
and ENDO for coliforms. The identification of bacteria was
performed by using fatty acid methyl esters. The counts resulted
positive to total coliforms and faecal coliforms in sites CR1
and CR2 and resulted negative in site CR3 except in autumn.
We isolated 469 strains, to...
117.
Responses of an Environmental Gram-negative Bacterium to Pollutant Stress
- Park, Buem-Seek
Several strains of pseudomonads which are normally found in natural water and soil
environments, including Pseudomonas fluorescens, Pseudomonas aeruginosa, and strains
initially identified as Pseudomonas paucimobilis and Pseudomonas maltophilia, were used in
this thesis and their stress responsive proteins were surveyed at the physiological level.
Additionally, 16S rRNA gene comparison was employed to classify the pseudomonads and
related species at the genetic level. In order to see to what extent the pseudomonads and related
species responded to heat shock, cells were initially subjected to temperature upshift from 28°C
to 37°C then disrupted by sonication or cells lysed by boiling in sample buffer, and the
extracted total proteins were...
118.
Identification of meat isolated bacteriocin-producing lactic acid bacteria using biotyping and ribotyping
- Martinis,E.C.P. De
Três cepas de bactérias láticas previamente isoladas a partir de produtos cárneos foram caracterizadas comparando-se resultados de testes bioquímicos e ribotipagem. Os resultados obtidos foram concordantes para Lactobacillus sake 1 e Lactobacillus curvatus 5. A cepa 16 foi identificada como Lactobacillus curvatus por testes bioquímicos e como Lactobacillus sake por ribotipagem, demonstrando a diferença entre as técnicas utilizadas. Recomenda-se, no momento, a técnica de ribotipagem para a identificação de bactérias láticas isoladas de carnes.
119.
Recuento de bacterias totales en leche cruda de tambos que caracterizan la zona noroeste de Santa Fe y sur de Santiago del Estero
- Revelli,G.R.; Sbodio,O. A.; Tercero,E.J.
Un total de 6.998 muestras de leche cruda de pool de tanque, correspondientes a 55 establecimientos lecheros asociados a la Cooperativa Tambera Nueva Alpina Ltda., fueron recolectadas entre los años 1993 y 2002. Se realizó el Recuento de Microorganismos Aerobios Mesófilos Totales, obteniéndose como resultado un valor medio de 1,2 x 105± 2,4 x 105UFC/ml que caracteriza la zona. El año de finalización de la experiencia, se observó un 97% de los tambos evaluados con promedios £ 1,0 x 105UFC/ml. Solamente un 3% sobrepasa este límite, no encontrándose establecimientos con niveles superiores a 1,5 x 105UFC/ml. Al relacionar este indicador...
120.
Recuento de bacterias totales en leche cruda de tambos que caracterizan la zona noroeste de Santa Fe y sur de Santiago del Estero
- Revelli,G.R.; Sbodio,O. A.; Tercero,E.J.
Un total de 6.998 muestras de leche cruda de pool de tanque, correspondientes a 55 establecimientos lecheros asociados a la Cooperativa Tambera Nueva Alpina Ltda., fueron recolectadas entre los años 1993 y 2002. Se realizó el Recuento de Microorganismos Aerobios Mesófilos Totales, obteniéndose como resultado un valor medio de 1,2 x 105± 2,4 x 105UFC/ml que caracteriza la zona. El año de finalización de la experiencia, se observó un 97% de los tambos evaluados con promedios £ 1,0 x 105UFC/ml. Solamente un 3% sobrepasa este límite, no encontrándose establecimientos con niveles superiores a 1,5 x 105UFC/ml. Al relacionar este indicador...
