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.     

A comparison of the predicted and X-ray structures of angiogenin. Implications for further studies of model building of homologous proteins

The three-dimensional structure of human angiogenin has been determined by X-ray crystallography and is compared here with an earlier model which predicted its structure, based on the homology of angiogenin with bovine pancreatic ribonuclease A. Comparison of the predicted model and crystal structure shows that the active-site histidine residues and the core of the angiogenin molecule, including most of the-strands and-helices, were predicted reasonably well. However, the structure of the surface loop regions and residues near the truncated C-terminus differs significantly. The C-terminal segment includes the active-site residues Asp-116, Gln-117, and Ser-118; Gln-117 in particular has been shown to be important in affecting the ribonucleolytic activity of angiogenin. Also, the orientation of one helix in the model differed from the orientation observed experimentally by about 20°, resulting in a large displacement of this chain segment. The difficulty encountered in predicting the surface loop regions has led to a new algorithm [Palmer and Scheraga (1991),J. Comput. Chem.,12, 505–526; (1992),J. Comput. Chem.,13, 329–350] for predicting the conformations of surface loops.     

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.     

Sterol and bile acid metabolism during development: 2. Identification of 3β-hydroxy-5-cholenoic acid (an intermediate in alternate pathway of bile acid synthesis) in newborn and fetal guinea pig

3β-hydroxy-5-cholenoic acid was found in the bile and feces of new-born and fetal guinea pigs. The identity of this compound was confirmed by gas chromatography and mass spectrometry. This finding suggests that the formation of chenodeoxycholic acid through 3β-hydroxy-5-cholenoic acid is intermediate in the early life of guinea pigs. Thus, it provides a useful model for studying the details of regulatory factors and significance of this pathway. This study also revealed that, unlike the adult guinea pig, the newborn guinea pig has significant amounts of glycine conjugates of bile acid.     

Responses of pulmonary C-fibre and rapidly adapting receptor afferents to pulmonary congestion and edema in dogs.

The effects of cardiogenic and noncardiogenic pulmonary edema on the activities of rapidly adapting receptors (RARs) and pulmonary C-fibre receptors were investigated in dogs anaesthetized with chloralose. Cardiogenic pulmonary edema was produced by elevating the mean left atrial pressure by 25 mmHg (1 mmHg = 133.32 Pa) above the control value for a period of 45 min, by partial obstruction of the mitral valve. Noncardiogenic pulmonary edema was produced by injecting alloxan (100 mg/kg) intravenously. The effect of the latter was examined on RARs alone. Cardiogenic edema activated RARs (n = 8) and the activity was greatest during the first few minutes after elevation of mean left atrial pressure. The pulmonary C-fibre receptors (n = 6) were also activated by cardiogenic edema, but these responses were variable. Noncardiogenic pulmonary edema also activated RAR (n = 6), and this response was maintained during the entire recording period (20 min). The extravascular lung water (%), measured 15 min (n = 5) and 45 min (n = 5) after the elevation of the mean left atrial pressure, was significantly elevated above control values. However, these two values were not significantly different from each other. The extravascular lung water increased significantly after the injection of alloxan also (n = 5). These results show that during pulmonary edema, there is significant stimulation of the RARs and the pulmonary C-fibre receptors. It is suggested that the reflex respiratory responses observed in pulmonary edema may be due to the activation of both the RARs and the pulmonary C-fibre receptors.     

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.