Multilayer adhesion to filter paper of two mesophilic, cellulolytic clostridiaGelhaye, E.; Claude, B.; Cailliez, C.; Burle, S.; Petitdemange, H.
doi: 10.1007/BF01577226pmid: N/A
Adhesive properties of a recently isolated, mesophilic, cellulolytic Clostridium (strain A22) and ofClostridium cellulolyticum (ATCC 35319) were described. For study of these properties, a method with Whatman No. 1 filter paper was developed, allowing faster kinetic analysis measuring “unbound” cells. This method was confirmed with [methyl-3H] thymidine to measure directly “bound” cells. The results of kinetic analysis indicated for the two clostridia a two-step adhesion process. In the first step, cell-cellulose interaction was observed. In the second step, cell-cell interaction was determined with an aggregation of cells away from the surface. This result was confirmed by scanning electron microscopy. Competition between strain A22 andC. cellulolyticum for adhesion sites was investigated. The two clostridia have the same specific adhesion sites was investigated. The two clostridia have the same specific adhesion sites on cellulose (filter paper), and unspecific interactions between two strains occur.
Lysine catabolism inStreptomyces ambofaciens producer of macrolide antibiotic, spiramycinUntrau, Sophie; Lebrihi, Ahmed; Germain, Pierre; Lefebvre, Gérard
doi: 10.1007/BF01577227pmid: N/A
Spiramycin production was highly stimulated when lysine was used as the sole nitrogen source. This amino acid was catabolized by the α-transaminase pathway characterized by dosage of cadaverine aminotransferase (CAT) enzyme. The Kmcadaverine was of 57mM. CAT was highly induced by lysine (634% in comparison with ammonium). Addition of 40mm of ammonium in a culture begun with 20mm of lysine as the sole initial nitrogen source repressed CAT biosynthesis by 24% but did not affect spiramycin production seriously. Addition of 20mm of lysine in a culture started with 40mm ammonium induced CAT biosynthesis of 425%, but did not allow spiramycin production. In these two cases, spiramycin production seems to be conditioned by the nitrogen source initially present in the culture medium. CAT activity was inhibited by ammonium ions (33% at 20mm), whereas lysine had no effects.
The effect of ionophores on proton flux in the ruminal bacterium,streptococcus bovisKajikawa, Hiroshi; Russell, J.
doi: 10.1007/BF01577229pmid: N/A
NonenergizedStreptococcus bovis cells, which were washed in potassium-phosphate buffer and incubated in Tris buffer containing 200mm potassium chloride (pH 6.5), did not take up tetraphenylphosphonium ion (TPP+), but the same cells took up TPP+ when they were incubated in Tris buffer lacking potassium. This result indicated that passive potassium diffusion was creating an electrical potential (ΔΨ) across the cell membrane. Neither cells took significant amounts of 9-aminoacridine (9-AA), an intracellular pH marker. Cells that were incubated in Tris buffer and treated with carbonyl cyanidem-chlorophenylhydrazone (CCCP) took up 9-AA, and this result indicated that this protonophore was facilitating proton influx. The ionophores monensin and lasalocid also caused 9-AA uptake, and it appeared that they were responsible for or responsive to potassium/proton antiport. However, there was also a rapid accumulation of 9-AA when the cells were treated with valinomycin, a potassium uniporter that cannot translocate protons. This latter result indicated that potassium efflux was associated with another avenue of proton influx (e. g., potassium/proton symport). Because cells treated with dicyclohexyl carbodiimide (DCCD) also exhibited valinomycin-dependent 9-AA uptake, it is unlikely that the F1F0ATPase or ATP formation was responsible for proton flux across the cell membrane.
Transformation of a psychrotrophic bacterium with a plasmid from a mesophileWhyte, Lyle; Inniss, William
doi: 10.1007/BF01577230pmid: N/A
The psychrotrophic bacteriumBacillus psychrophilus was transformed with the broadhost-range plasmid pC194. The ability of the transformant to express chloramphenicol (CAM) resistance and the possible effects of such expression on the physiology of the psychrotroph were examined. The transformant exhibited growth rates, filament formation at elevated temperatures, synthesis of cold shock proteins and cold acclimation proteins, similar to the parentalB. psychrophilus.
Effect of osmolarity and dehydration on alginate production by fluorescent pseudomonadsSingh, Shrikrishna; Koehler, Betty; Fett, William
doi: 10.1007/BF01577231pmid: N/A
Alginate is produced as an exopolysaccharide by many fluorescent pseudomonads. However, pseudomonads often have a nonmucoid phenotype in standard laboratory media. Growth in the presence of 0.3M sodium chloride or 3–5% ethanol reportedly can lead to the generation of mucoid variants of nonmucoid strains ofPseudomonas aeruginosa. We wished to determine whether alginate production by other fluorescent pseudomonads is affected by sodium chloride and ethanol. Eight alginate-producing strains of saprophytic and phytopathogenic pseudomonads were grown as broth cultures containing 0–0.7M sodium chloride or 0–5% ethanol for 24–30 h at 28° or 35°C. Culture supernatant fluids were subjected to ethanol precipitation, and the amount of alginate present was estimated by measuring the uronic acid content. The presence of sodium chloride and ethanol caused significant stimulation of alginate production by all strains tested exceptP. viridiflava ATCC 13223 andP. fluorescens W4F1080. The optimal concentration of sodium chloride ranged from 0.2 to 0.5M; that for ethanol ranged from 1 to 3%. Moreover, inclusion of the nonmetabolizable, nonionic solute sorbitol showed a similar stimulation of alginate production. The stimulation of alginate production by high medium osmolarity and dehydration appears to be a trait shared by fluorescent pseudomonads.
Coexistence of parentalBacillus brevis and its gramicidin S-negative mutant during spore germination stagesKuhnt, Dorothée; Demain, Arnold
doi: 10.1007/BF01577232pmid: N/A
Bacillus brevis strain Nagano and its gramicidin S-negative mutant, BI-7, were compared in separate as well as in mixed cultures with respect to germination of their spores in several media. Mixed-culture experiments were facilitated by the observation that colonies of wild and mutant cultures are distinctly different in appearance on nutrient agar. We found that there was complete coexistence in both strains throughout the outgrowth phase of germination, during which gramicidin S-induced suicide normally occurs in the wild-type prior to vegetative growth. Coexistence was also observed in media supporting germination but not growth, i.e., alanine-salts and alanine-water. The same was found when spores of the two strains were incubated in a soil suspension. We found that both strains become sensitive to starvation in a salts mixture only after development into vegetative cells, the mutant strain being more sensitive than the parent in this regard, but again coexistence was observed in mixed culture.
Isolation and characterization of siderophore, with antimicrobial activity, fromAzospirillum lipoferum MShah, Samir; Karkhanis, Vaidehi; Desai, Anjana
doi: 10.1007/BF01577233pmid: N/A
Azospirillum lipoferum M was found to produce catechol-type of siderophores under iron-starved conditions. Chemical characterization of siderophores revealed the presence of salicylic acid, 2,3-dihydroxybenzoic acid (DHBA), and 3,5-DHBA conjugated with threonine and lysine. Siderophore production was found to be maximum after 28 h of growth. In addition to their established role in iron transport, the siderophores exhibited antimicrobial activity against various bacterial and fungal isolates.