Conformational studies of A23187 with mono-, di- and trivalent metal ions by circular dichroism spectroscopy

CD studies carried out on A23187 indicate a solvent-dependent conformation for the free acid. Alkali metal ions were found to bind to the ionophore weakly. Divalent metal ions such as Mg2+, Ca2+, Sr2+, Ba2+ and Co2+ and trivalent lanthanide metal ions like La3+ were found to form predominantly 2:1 (ionophore-metal ion) complexes at low concentrations of metal ions, but both 2:1 and 1:1 complexes were formed with increasing salt concentration. Mg2+ and Co2+ exhibit similar CD behaviour that differs from that observed for the other divalent and lanthanide metal ions. The structure of 2:1 complexes involves two ligand molecules coordinated to the metal ion through the carboxylate oxygen, benzoxazole nitrogen and keto-pyrrole oxygen from each ligand molecule along with one or more solvent molecules. Values of the binding constant were determined for 2:1 complexes of the ionophore with divalent and lanthanide metal ions.     

A rapid method for monitoring intracellular lipid production using1H NMR spectroscopy

Summary A method has been developed for rapid mondtoring of lipid production in the intact yeast cells ofRhodotorula gracilis using¹H NMR spectroscopy.     

Acute and chronic effects of insulin on lactate dehydrogenase (LDH) activity in tissues of albino rat (Wistar strain)

Male albino rats were treated with insulin for one week (acute) and four weeks (chronic). The lactate dehydrogenase (LDH) activity, lactate and pyruvate levels were estimated in the tissues of experimental and control animals. LDH activity decreased in all the tissues of acute- and chronic treated animals whereas the lactate content is elevated. Pyruvate content also showed increment except in heart and pancreas with reference to acute treatment where it is decreased. The hyperinsulinaemia effect in relation to lacticacidaemia and its influence on energy demand and ammonia secretion is discussed.     

Ultrastructural localization of an extracellular protease in Pseudomonas fragi by using the peroxidase-antiperoxidase reaction.

An extracellular protease, which previously has been found to correlate with the appearance of bleblike evaginations on the cell wall of Pseudomonas fragi ATCC 4973, was purified 38-fold by ammonium sulfate precipitation and Sephadex chromatography to yield a single band by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Polyclonal rabbit antiserum raised against the purified enzyme had an enzyme-linked immunosorbent assay titer of 4 X 10(7). The peroxidase antiperoxidase method was used to localize the neutral protease in P. fragi at the ultrastructural level. Electron microscopy of cell sections of this organism revealed that high concentrations of positive immunoperoxidase reaction product were located near the cell wall, whereas control sections stained with preimmune or heterologous serum did not show similar deposits to be present. These results are consistent with the hypothesis that blebs appearing on P. fragi contain high concentrations of neutral protease.     

Ultrastructural localization of an extracellular protease in Pseudomonas fragi by using the peroxidase-antiperoxidase reaction

An extracellular protease, which previously has been found to correlate with the appearance of bleblike evaginations on the cell wall of Pseudomonas fragi ATCC 4973, was purified 38-fold by ammonium sulfate precipitation and Sephadex chromatography to yield a single band by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Polyclonal rabbit antiserum raised against the purified enzyme had an enzyme-linked immunosorbent assay titer of 4 X 10(7). The peroxidase antiperoxidase method was used to localize the neutral protease in P. fragi at the ultrastructural level. Electron microscopy of cell sections of this organism revealed that high concentrations of positive immunoperoxidase reaction product were located near the cell wall, whereas control sections stained with preimmune or heterologous serum did not show similar deposits to be present. These results are consistent with the hypothesis that blebs appearing on P. fragi contain high concentrations of neutral protease.     

Studies on freshwater protozoa of South India II: Ciliophora

Summary A systematic account of 81 species of free living ciliophora found living in dirty water of gutters, ditches, wells, tanks etc. belonging to 31 families of Euciliata and Suctoria is given in this paper. It includes 30 new records for the Indian sub-continent and 37 new records for the Southern region.     

Incidence of enterotoxin producing Staphylococcus aureus among pyogenic skin infections

Out of the total 68 S. aureus strains isolated and studied from pyoderma patients, 33 (48.5%) strains produced enterotoxin. Isolates from IED, impetigo and folliculitis exhibited high degree of enterotoxigenicity. SE-C and its combinations with other enterotoxins was common. 60.6% of the SE producers were found phage nontypable. Typable enterotoxigenic strains were associated with III, IV and mixed phage groups. S. aureus var. hominis and S. aureus var. bovis are the prevalent subspecies types and potent SE producers among pyogenic skin infections.     

Seasonal pattern of photosynthetic rate and its relationship with chlorophyll content,ribulose-1,5-bisphosphate carboxylase activity and biomass production

Net photosynthetic rate (P_N), ribulose-1,5-bisphosphate carboxylase (RuBPC) activity, chlorophyll (Chl) content and biomass production were estimated at monthly intervals inChukrasia tabularis, Dolichandrone atrovirens, Eugenia jambolana, Gmelina arborea, Lannea coromandelica, Terminalia arjuna andTerminalia bellerica from September 1990 to August 1991. The leaves of all the seven tree species showed significantly higher P_N during summer than in winter and these rates differed from one species to the other. A positive correlation was found between P_N of different tree species and their Chl content or biomass production. There was no significant correlation between ribulose-1,5-bisphosphate carboxylase activity and P_N when these were expressed on leaf area basis.     

Effect of sciatectomy and induced ammonia stress on Mg2+_adenosine triphosphatase activity in frog tissues

Mg² + dependent —adenosine triphosphatase activity has been studied in the muscle, brain, kidney and liver tissues of frog,Rana hexadactyla (Lesson) after sciatectomy and induced chronic ammonia stress. The enzyme activity decreased in the tissues of the denervated frog. The activity of the enzyme increased in all the tissues of the normal and denervated frogs except in the denervated muscle when ammonium lactate was infused intraperitoneally.     

Aquatic oligochaeta from among the roots of eichhornia crassipes solms

The paper records the presence of sixteen species of aquatic oligochaetes, belonging to the Aeolosomatidae (1 species). Naididae (13 species) and Tubificidae (2 species), living in association with the floating roots of the water hyacinth, Eichhornia crassipes Solms., from a tank in Vizianagaram town in Andhra Pradesh, India. Of these, Aeolosoma hyalinum Bunke, 1967 and Dero obtusa D'Udekem, 1855 are new records for the Indian sub-continent.