Partial purification and characterization of a gelatin-specific protease from the culture media of human pulmonary alveolar macrophages

A gelatin-specific protease from the culture media of human pulmonary alveolar macrophages has been partial purified by gel filtration and characterized. The macrophages were obtained by bronchopulmonary lavage from the lungs of disease-free smoking volunteers. The gelatin-specific protease initially requires trypsin activation. After chromatographing the culture media on a Sephadex G-200 column, trypsin is no longer required for activation. The gelatin-specific protease reported here shares many properties of previously reported gelatinases. It is inhibited by EDTA, cysteine, dithiothreitol and serum. It is unaffected by other protease inhibitors: phenylmethylsulfonyl fluoride, tosyllysine chloromethyl ketone and p-chloromercuribenzoate. Of all substrates tested activity was observed only with gelatin. It was inactive toward collagen, elastin and methemoglobin. This enzyme may have a role in the digestion of collagen which has been cleaved by a mammalian collagenase.     

Intensification of alcoholic fermentation upon dehydration-rehydration of the yeast Saccharomyces cerevisiae

Summary In comparison with intact yeast, dehydrated-rehydrated cells of Saccharomyces cerevisiae show significantly higher ethanol production from exogenous substrate under both anaerobic and aerobic conditions, particularly when low concentration (0.1%) of glucose are used. For populations with a higher percentage of viable rehydrated cells (above 70%) a more notable decrease in the Pasteur effect (the difference between the quantity of ethanol formed under anaerobic and aerobic conditions) is observed.     

Isolation and Pathogenicity of Rhizosphere Fungi of Cocoyam in Relation to Cocoyam Root Rot Disease

Cocoyam is the second most important staple crop of Cameroon and root rot is a destructive disease of this plant. Pythium myriotylum (Pm), Fusarium solani (Fs), and Rhizoctonia solani (Rs) were isolated from the rhizosphere of root rot affected cocoyams and from the soil of a cocoyam experimental field plot temporarily devoid of same in Mamu, Cameroon. Pm was isolated from the above soil by the cocoyam leaf disc baits. Fs and Rs were also isolated from the same soils by the water dilution method and from the roots of diseased cocoyams but were always associated with mycelial growth of Pm. Pathogenicity of Pm and in combinations with Fs or Rs or Fs + Rs all developed cocoyam root rot disease (CRRD) symptoms on 3– and 7–month old cocoyam plantlets 2–7 days after inoculation. Symptoms included rotted roots and wilting with general chlorosis of inoculated plantlets. No symptoms of CRRD were noted on cocoyam plantlets inoculated with Fs, Rs, Fs + Rs, and distilled water. Results indicated that CRRD is not caused by several pathogens but only by Pm. Pm isolates from the soils and roots of diseased cocoyams and those maintained in the ROTREP laboratory have significantly bigger diameter of mycelial colony growth in 24 h–period at 31 °C on lima bean sucrose agar, V–8 juice sucrose agar, and potato sucrose agar than on potato dextrose agar and 2 % water agar. The cocoyam plantlets were raised axenically from tissue culture of explants in the laboratory.     

Skeletal muscle creatine kinase MB alterations in women marathon runners

Total creatine kinase (CK) and CK MB activities were determined in gastrocnemius muscle and serum obtained from 14 female marathon runners. The level of CK MB in muscle increased significantly (p less than 0.05) after chronic exercise training from 5.3% to 10.5% of the total CK activity, but not after acute exercise (post-marathon 8.9%). No significant differences in total CK activities were detected. However, the total CK activity in the muscles were significantly (p less than 0.05) less than those previously reported from the muscle of men runners (1800 U/g, 3000 U/g respectively). No significant correlation existed between fiber type and muscle CK MB activity. Additionally, trace amounts of mitochondrial CK and CK BB were present in muscle homogenates. A significant correlation was observed in the increase in mean serum total CK (597 UL-1) and CK MB (23 UL-1) activities 24 h after the race (r = 0.97, p less than 0.05). These results suggest that gastrocnemius muscle in women adapts to training with increased CK MB activities and imply that skeletal muscle is the major source of elevated serum CK MB activities in women marathon runners.     

Biology of Elodea canadensis mich. and its management in Australian irrigation systems

The seasonal growth and decline of a population of Elodea canadensis Mich. growing in an irrigation drain are described, together with some characteristics of the aquatic environment (turbidity, photosynthetically-available radiation, temperature and pH). Overwintering buds (up to 5000 m^?2) in the form of swollen dormant stem apices are produced in autumn with the onset of cold weather, remain in the mud, and grow out in the spring. In late summer vegetative reproduction also occurs when large numbers of the leafless stem portions which are capable of growing into independent plants are swept downstream from established populations. Results suggest that control measures should be applied in early summer when populations are approaching nuisance size, and again in late summer before fragmentation occurs and overwintering propagules are initiated. In irrigation channels in Australia, where draining and drying are not feasible, biomass in successfully reduced by widespread use of herbicides.     

Theoretical models for cooperative steady-state ATPase activity of myosin subfragment-1 on regulated actin

Recent theoretical work on the cooperative equilibrium binding of myosin subfragment-1-ADP to regulated actin, as influenced by Ca2+, is extended here to the cooperative steady-state ATPase activity of myosin subfragment-1 on regulated actin. Exact solution of the general steady-state problem will require Monte Carlo calculations. Three interrelated special cases are discussed in some detail and sample computer (not Monte Carlo) solutions are given. The eventual objective is to apply these considerations to in vitro experimental data and to in vivo muscle models.     

Field performance of micropropagated,macropropagated, and seed-derived propagules of three Eucalyptus grandis ortets

Tree size, survival, and coppicing of micropropagated plantlets, macropropagated cuttings, and seedlings of Eucalyptus grandis Hill ex Maiden were monitored through 57 months in a study in southern Florida to assess propagation options. Two plantlet lines developed by direct micropropagation and orchard open-pollinated seedlings from three ortets were compared in the main study. Rooted cuttings from up to four ramets of each of the three ortets and another ortet were examined in an adjacent supplemental study. Freezes at six and 16 months killed most initial and first-coppice stems to the ground. Most developmental differences in the main study were consistent from ages 2 to 57 months. Propagation by ortet interactions were observed beginning at 21 months, due to the poor performance of seedlings of one ortet after the second freeze. At 57 months, no differences in tree height, DBH, volume, or survival were detected between plantlet lines and between rooted cuttings and plantlets, but seedlings were inferior to plantlets and cuttings. Vegetative propagules had more uniform tree size at every age, with typically less than one-half the variability observed among seedlings. Even though plantlets and cuttings may be more expensive to produce, they have numerous advantages over seedlings for E. grandis plantation establishment in Florida.