142.
Chemical characterization of exopolysaccharides from Antarctic marine bacteria - NICHOLS, Carol; LARDIERE, Sandrine; BOWMAN, John; NICHOLS, Peter; GIBSON, John; GUEZENNEC, Jean
Exopolysaccharides (EPS) may have an important role in the Antarctic marine environment, possibly acting as ligands for trace metal nutrients such as iron or providing cryoprotection for growth at low temperature and high salinity. Ten bacterial strains, isolated from Southern Ocean particulate material or from sea ice, were characterized. Whole cell fatty acid profiles and 16S rRNA gene sequences showed that the isolates included representatives of the genera Pseudoalteromonas, Shewanella, Polaribacter, and Flavobacterium as well as one strain, which constituted a new bacterial genus in the family Flavobacteriaceae. The isolates are, therefore, members of the "Gammaproteobacteria" and Cytophaga-Flexibacter-Bacteroides, the taxonomic...
143.
Caracterização das atividades proteolíticas da bactéria anaeróbia fusobacterium nucleatum - Alice Tayoko Ogawa
Foram determinadas as atividades proteolíticas do bacilo anaeróbio Fusobacterium nucleatum, presente em várias infecções oral e sistêmica humana. As reações foram otimizadas quanto a pH, temperatura, tempo de reação, volume da fonte de enzima e concentração de substrato. Foram utilizados os substratos sintéticos b-naftilamida (Cys-Na, Ser-Na, Leu-Na, Glu-Na, Lys-Na e BANA), o carboxi-L-tirosina p-nitrofeniléster (CTN) e o substrato natural azoalbumina. Reação do sobrenadante ocorreu apenas com o substrato Glu-Na. Nas células vivas, as reações ocorreram com Cys-Na, Ser-Na e Glu-Na; e com as células lisadas, com os substratos Glu-Na, Leu-Na e CTN. O pH ótimo variou de 6,0 a 7,5...
146.
LEVELS AND TYPES OF AEROBIC SPORE FORMING BACTERIA ASSOCIATED WITH DRIED MATEMBA, (LIMNOTHRISSA MIODON) - Dube, S; Department of Applied Biology and Biochemistry, National University of Science and Technology P.O Box 939AC Ascot, Bulawayo, Zimbabwe; sdube@nust.ac.zw; Dlamini, NR; Department of Applied Biology and Biochemistry, National University of Science and Technology P.O Box 939AC Ascot, Bulawayo, Zimbabwe;; Muzungu, W; Department of Applied Biology and Biochemistry, National University of Science and Technology P.O Box 939AC Ascot, Bulawayo, Zimbabwe;
Matemba, a small fish harvested from Lake Kariba is one of the affordable protein sources for the under privileged in Zimbabwe. The fish, which does not exceed 3 g dry mass, and 5 cm in length is caught using nets. It is dried whole, with no thorough cleaning or disemboweling done. The suspended drying open nets are used over and over without thorough cleaning. The fish is then sold to packaging companies who pool the fish from different sources before weighing and packaging them into polythene bags. The manner in which the fish is handled during the processing was suspected...
147.
Lactic acid bacteria from fresh fruit and vegetables as biocontrol agents of phytopathogenic bacteria and fungi - Trias, Rosalia; Bañeras, Lluís; Montesinos Seguí, Emilio; Badosa Romanyó, Esther
This study evaluated the efficacy of lactic acid bacteria (LAB) isolated from fresh fruits and vegetables as biocontrol
agents against the phytopathogenic and spoilage bacteria and fungi, Xanthomonas campestris, Erwinia carotovora,
Penicillium expansum, Monilinia laxa, and Botrytis cinerea. The antagonistic activity of 496 LAB strains was tested in vitro and all tested microorganisms except P. expansum were inhibited by at least one isolate. The 496 isolates were also analyzed for the inhibition of P. expansum infection in wounds of Golden Delicious apples. Four strains (TC97, AC318, TM319, and FF441) reduced the fungal rot diameter of the apples by 20%; only Weissella cibaria...
153.
Cambios en la viabilidad de dos bacterias marinas antárticas expuestas a la radiación solar en la columna de agua: influencia de la mezcla vertical - Hernández,E. A.; Mac Cormack,W. P.
Se estudió el efecto de la radiación ultravioleta (RUV) sobre dos cepas bacterianas marinas antárticas (UVps y UVvi) en la columna de agua de la caleta Potter (Shetland del Sur, Antártida). Frascos de cuarzo con las cepas en estudio fueron expuestos a la radiación solar en superficie, a 1 m y a 3 m de profundidad. Se realizaron ensayos con exposición directa y con filtros interferenciales que discriminaron la radiación UVA y la UVB. En otros ensayos se simuló una mezcla vertical de 4 m/h. Ambas cepas mostraron una disminución significativa del número de unidades formadoras de colonias, tanto en...
154.
Cambios en la viabilidad de dos bacterias marinas antárticas expuestas a la radiación solar en la columna de agua: influencia de la mezcla vertical - Hernández,E. A.; Mac Cormack,W. P.
Se estudió el efecto de la radiación ultravioleta (RUV) sobre dos cepas bacterianas marinas antárticas (UVps y UVvi) en la columna de agua de la caleta Potter (Shetland del Sur, Antártida). Frascos de cuarzo con las cepas en estudio fueron expuestos a la radiación solar en superficie, a 1 m y a 3 m de profundidad. Se realizaron ensayos con exposición directa y con filtros interferenciales que discriminaron la radiación UVA y la UVB. En otros ensayos se simuló una mezcla vertical de 4 m/h. Ambas cepas mostraron una disminución significativa del número de unidades formadoras de colonias, tanto en...
158.
Genome Composition of Endosymbiotic Bacteria - Jrg Schaber,Claude Rispe,Franois Delmotte,Francisco Silva
Introduction
Due to small effective population sizes and lack of recombination, the efficacy of selection is assumed to be
reduced in the genomes of endosymbiontic bacteria, according to the neutral and slightly deleterious theory of
evolution. Five such genomes have been completely sequenced, i.e. Buchnera aphidicola (BAp, BSg, BBp),
Wigglesworthia glossinidia (Wgl) and Blochmannia floridanus (Bfl). Indeed, it was found that genomes of these
endosymbionts show a strong reduction in genome size, AT enrichment and accelerated rates of evolution
concerning both non-synonymous and synonymous substitutions [1-3]. The AT enrichment and increased
evolutionary rates have largely been attributed to a deleterious process [4]. However, an alternative interpretation
has been...
141.
