β-D-galactosidase ofLactobacillus speciesCesca, B.; Manca de Nadra, M. C.; Strasser de Saad, A. M.; Pesce de Ruiz Holgado, A.; Oliver, G.
doi: 10.1007/bf02875959pmid: 6434381
The activity of β-D-galactosidase was studied in 13 strains of lactobacilli (groupsStreptobacterium, Thermobacterium andBetabacterium). Using 2-nitrophenyl galactopyranoside as substrate, the enzyme activity varied with the strain. The values found in theThermobacterium group were superior to those in theStreptobacterium group. The optimum pH for the species belonging to theThermobacterium group was uniform, in contrast to the ph for those from theStreptobacterium which varied according to the species. The optimum temperature was quite uniform within each group and higher in theStreptobacterium. Lactose acted as a competitive inhibitor. MgCl2 protected the enzyme from thermal denaturation. The calcium ions inhibited the activity in all cases. The behaviour of the protectors of the SH groups varied according to the strain. 6-Phospho-β-D-galactosidase activity was also determined, levels lower than β-D-galactosidase were found, except inLactobacillus plantarum ATCC 8014 and 14917.
Regulation of the biosynthesis of ergot alkaloids byPenicillium sizovaeKozlovsky, A. G.; Reshetilova, T. A.
doi: 10.1007/bf02875961pmid: N/A
To investigate the regulation of the biosynthesis of ergot alkaloids by end products, the effect of exogenous agroclavine-1 and epoxyagroclavine-1 on their accumulation byP. sizovae was studied. The added alkaloids stimulated considerably their own biosynthesis depending on their concentration and time of introduction. The stimulating effect of both alkaloids and products of their degradation was suggested. Exogenous agroclavine-1 and epoxyagroclavine-1 changed the relation between the quantities of intra-and extracellular alkaloids, thus pointing to their possible influence on the transport processes.
Laccase production and wood degradation byTrametes hirsutaArora, D. S.; Sandhu, D. K.
doi: 10.1007/bf02875963pmid: N/A
The laccase production byT. hirsuta was better in lignin as compared to malt extract media. Tannic acid gave the best laccase yield out of different lignins, phenolic compounds and sugars tested as substrates. The sugars proved to be good substrates for growth only. The role ofT. hirsuta in semisolid fermentation of sawdust was studied with reference to its capacity to degrade lignin in its native form. During two months of decay an overall weight loss of 22.2% along with a lignin loss of 13.6% was recorded.
Salinity tolerance of aRhizobium meliloti strain isolated from salt affected soilsDouka, C. E.; Xenoulis, A. C.; Paradellis, T.
doi: 10.1007/bf02875964pmid: N/A
The salinity tolerance of aRhizobium meliloti strain isolated from salt-affected soils was examined. Growth of the strain on yeast—mannitol broth containing 0–1.2% NaCl exhibited in all cases the same generation time and simultaneous onset of the stationary phase while the total viable number of cells was the same for three continuous generations. The nodulation, plant yield and elemental composition ofMedicago sativa plants grown on agar slopes, inoculated with cultures from the third generation grown on broth containing 0–1.2% NaCl responded identically to all inocula. The salinity tolerance of the strain in fixing nitrogen was furthermore demonstrated withM. sativa plants grown on either nitrogen-free agar slopes containing 0.2–1.2% NaCl or soil-agar slopes with saline soil in which 0.15 and 0.3% additional NaCl was used.
Effect of fuel burning on the microbial population of soilDeka, H. K.; Mishra, P. R.
doi: 10.1007/bf02875966pmid: N/A
An attempt was made to study the effect of different amount of fuel burning on the microbial populations of forest soil. Maximum effect of fire was observed in the surface layer of soil and not much variation was seen in the distribution of soil microflora. However, with increasing amount of fuel burned, the effect became higher, microorganisms being destroyed to a depth of 70 mm. Qualitatively, there was no significant difference in the composition of fungal species in comparison with the control soil. Similar types of fungal species were isolated from all the types of burned soil,Aspergillus, Penicillium, Trichoderma, Fusarium andPhoma being the predominant genera.
Intracellular nuclease activities of buffalo rumen bacterial populationSinha, P. R.; Dutta, S. M.
doi: 10.1007/bf02875967pmid: 6479756
Nuclease activities of the predominantly bacterial population obtained from buffalo rumen were investigated. Optimum temperature for hydrolysis of both DNA and RNA was 50°C whereas DNAase activity was observed to be stable up to 50°C, a decrease in RNAase activity was observed even after 40°C. Two pH optima, one at 5.5 and the other at 7.5, were recorded for hydrolysis of DNA. RNAase activity was maximum between pH 6.0 to 7.0. Whereas DNAase activity was stable near its optimum pH, RNAase activity was stable between pH 7.0 to 8.5. Mn2+ ions stimulated DNAase activity. It was strongly inhibited by Hg2+, Zn2+, Pb2+ and Ag+. RNAase activity was stimulated by Mg2+ ions and was strongly inhibited by Hg2+, Cu2+, Zn2+ and Ag+. Cysteine hydrochloride and 2-mercaptoethanol stimulated DNAase activity. The activity was strongly inhibited by N-ethylmaleimide, 4-chloromercuribenzoate, 8-quinolinol, iodoacetic acid and 1,10-phenanthroline. RNAase activity was stimulated by cysteine hydrochloride, reduced glutathione and 2-mercaptoethanol and was strongly inhibited by 4-chloromercuribenzoate, 8-quinolinol and 2,2′-bipyridyl.