Dissociation and reassociation of rabbit skeletal muscle myosin

Whereas dissociation of rabbit skeletal muscle myosin light chains occurs at an increased temperature (25°) and in the obsence of divalent cations, reassociation of the myosin oligomer requires a low temperature (4°C) and the presence of divalent cations, thus resulting in the original light to heavy chain stoichiometry. With a 5–10 per cent release of alkali light chains, LC₁ and LC₃, and a 50 per cent dissociation of the Ca²⁺ binding light chain, LC₂, there is no significant decrease in myosin ATPase activity irrespective of the cation activator, however, there is an approximate 15–20 per cent decrease in actomyosin ATPase activity. With reassociation of the myosin oligomer, actomyosin ATPase activity is partially restored as well as the original number of Ca²⁺ binding sites.     

Parameter Estimation for the Compartmental Model

An estimation procedure is obtained for a stochastic compartmental model. Compartmental analysis assumes that a system may be divided into homogeneous components, or compartments. The main theory for the compartmental system was studied by Matis and Hartley (1971) with a discrete population in a steady state. All the transitions among the particles are considered to be stochastic in nature. An estimation procedure, Regular Best Asymptotic Normal (RBAN), discussed by Chiang (1956) is investigated for a stochastic m-compartmental system. The detailed proof of the procedure is provided here. Asymptotic properties for the estimator has been studied and computation has been carried out on our proposed nonlinear model. The downhill simplex search method, originally developed by Nelder and Mead (1965), and applied to minimize our quadratic form is inherently nonlinear in nature, thus avoiding the need to evaluate any derivative for point estimation of the parameters. The procedure applied to an experimental situation involving two compartments gives very encouraging results.     

The peroxidatic and catalatic activity of catalase in normal and acatalasemic mouse liver

Monomeric, dimeric and tetrameric forms of mouse liver catalase have been shown to express peroxidatic activity while the tetrameric form expresses the catalic activity. Autosomally inherited acatalasemia, produced by X-ray irradiation of mice results in almost complete loss of catalic activity of catalase but has no effect on the peroxidatic activity. Liver catalase from normal and acatalasemic mice was purified by following the catalic and peroxidatic activity, respectively. Antiserum produced in rabbit against catalase from normal mouse completely precipitated the catalatic and peroxidatic activity from normal liver, and peroxidatic activity from the acatalasemic liver homogenate. Similar results were obtained when antiserum against peroxidase from acatalasemic mice was used. These studies indicate that acatalasemia in mice is due to a structural gene mutation which leads to synthesis of structurally altered catalase subunits. The altered subunits express peroxidatic activity but do not combine to form a tetramer which expresses catalatic activity.     

Buffering effect of B-chromosome system of Trigonella foenum-graecum against different soil types

Summary Accessory (B–) chromosomes have been reported in many plants in various regions of the world. Studies on natural populations of certain plants like Phleum phleoides revealed that B-chromosomes were present in different frequencies in different habitats indicating a correlation between B-frequency and environmental conditions. The present experiment was performed to determine the response of B-chromosome carrier and non-carrier plants of Trigonella to different soil conditions. When the morphological data was subjected to analysis of variance, it was found that the carrier plants exhibited uniformity of characters in the different soil types, while the non-carrier plants exhibited considerable variability. The conclusion that can be drawn from this experiment is that B-chromosomes act as a buffering agent, neutralising the variability effect of different soil types.     

Leucocyte Culture and Chromosome Preparations from Pig Blood

Blood was drawn into heparinized tubes from any large vein and allowed to settle 2-3 hr at 3-5 C. The cell sample consisting of 1 ml drawn from the buffy coat and 2 ml from the plasma was planted in the following medium: Medium 199 (Difco), 10 ml; penicillin G sodium, 1000 USP units; dihydrostreptomycin, 1 mg; and Bacto-PHA-M (Difco), 0.2 ml. Incubation, with twice daily shaking, was at 37 C for 68-70 hr; colchicine to give 4 μ ml was then added and incubation continued for 3-4 hr. The bulk of the medium was removed by centrifugation, the cells washed once in Hanks' salt solution, centrifuged, and all but 0.5 ml of the fluid decanted; 1.5 ml of distilled water at 37 C was added, the cell suspension incubated at 37 C 5-15 min, followed by centrifugation and fixation in methanolacetic acid 3:1 (3 changes) as usual. Spreads were made by applying 4-5 drops of cell suspension to ice-cold slides and burning off the fixative. Giemsa stain was used. The method has proved very satisfactory for determining chromosome numbers in the domestic pig. This number, as determined in 690 cells from Poland China and Duroc gilts and crosses of these breeds was 38 in 611 (88.6%) of the cells.     

Aeromycology of Gorakhpur

The present paper deals with the air fungi of a paddy field. The investigation was carried on from August '67 to November '67. The fungal flora continuously increased from August to November. The dominant and subdominant species differed from month to month and sometimes even at different sampling periods.Aspergilli andHelminthosporium were dominant withCurvularia andFusaria as subdominant in earlier part of the investigation. Later on, the air spores were dominated byCladosporium withHelminthosporium and above two subdominants.     

Host range of Achlya orion Coker & Couch on certain freshwater fishes

By the present investigations the host range of Achlya orion Coker and Couch has been extended to, Puntius sophore, Puntius ticto, Puntius conchonius, Puntius sarana, Chanda ranga, Channa marulius, Channa punctatus, Notopterus notopterus, Labeo rohita, Colisa lalia and Anabas testudineus; 11 freshwater fishes.The ability of certain Saprolegniaceous fungi to parasitise fish has been reported by several investigators viz., Clinton (2), Tiffney (21, 22), Tiffney & Wolf (23), Gopalakrishnan (3), Vishniac & Nigrelli (24), Scott & O'Bier (7), Bhargava et al (1) and Srivastava & Srivastava (10.20) etc. These fungi are known to attack fish eggs, fry, fingerling and adult fishes and as a general rule the fungal infection starts when the host gets injured either mechanically or as result of infections other than fungal which often result in epidemics causing 100% mortality of the infected hosts (Scott & O'Bier 7).During the course of an investigation on fungi associated with fish diseases, author observed the severe fungal infections of Colisa fasciatus (Bl.) and Anabas testudineus (Bl.) in the waters of Ramgarh Lake, Gorakhpur, causing heavy mortality of the infected hosts. The fungus was identified as Achlya orion Coker Couch and its pathogenicity was also established by conducting laboratory inoculation experiments on the lines of Scott & O'Warren (8); (Srivastava & Srivastava, 14).In view of the above observations, it seemed desirable to investigate the host range of this mould on accurately identified hosts in order to asses the extent of damage done to such fishes.