Skeletal troponin I as a marker of exercise-induced muscle damage

Sorichter, Stephan, Johannes Mair, Arnold Koller, WalterGebert, Daniel Rama, Charles Calzolari, Erika Artner-Dworzak, and BerndPuschendorf. Skeletal troponin I as a marker of exercise-inducedmuscle damage. J. Appl. Physiol.83(4): 1076-1082, 1997.The utility of skeletal troponin I (sTnI)as a plasma marker of skeletal muscle damage after exercise wascompared against creatine kinase (CK), myoglobin (Mb), and myosin heavychain (MHC) fragments. These markers were serially measured in normalphysical education teacher trainees after four different exerciseregimens: 20 min of level or downhill (16% decline) running(intensity: 70% maximal O₂uptake), high-force eccentric contractions (70 repetitions), orhigh-force isokinetic concentric contractions of the quadriceps group(40 repetitions). Eccentrically biased exercise (downhill running andeccentric contractions) promoted greater increases in all parameters.The highest plasma concentration were found after downhill running{median peaks: 309 U/l CK concentration ([CK])}, 466 µg/l Mb concentration([Mb]), 1,021 µU/l MHC concentration ([MHC]),and 27.3 µg/l sTnI concentration ([sTnI]). Level running produced a moderate response (median peaks: 178 U/l [CK],98 µg/l [Mb], 501 µU/l [MHC], and 6.6 µg/l [sTnI]), whereas the concentric contraction protocoldid not elicit significant changes in any of the markers assayed. sTnIincreased and peaked in parallel to CK and stayed elevated (>2.2µg/l) for at least 1-2 days after exercise. In contrast to MHC,sTnI is an initial, specific marker of exercise-induced muscle injury,which may be partly explained by their different intracellularcompartmentation with essentially no (MHC <0.1%) or a small solublepool (sTnI: median 3.4%).

     

Effect of topsoil storage on microbial activity,primary production and decomposition potential

Summary The effects of disturbing (cultivating) and stockpiling prairie grassland topsoil on microbial activity, microbial biomass C, plant production and decomposition potentials were studied by measuring CO₂ efflux from unamended and glucose amended soil in the laboratory and by conducting a pot and litter bag study in the greenhouse. Stockpiling appeared to have very little effect on soil respiratory activity, but did reduce the microbial biomass C levels. Throughout the 3 year study the microbial biomass C in the surface soil of the stockpile was less than that in the undisturbed soil, while the biomass C in soil at the bottom of the stockpile was at no time significantly different from that in the undisturbed soil. The reduction in microbial biomass C in the surface soil immediately after stockpiling was attributed to a decrease in the soil organic C levels caused by a slight dilution of the topsoil with subsurface mineral soil, and the exposure of the stockpile surface to extreme environmental conditions. Soils from all depths of the stockpile responded more slowly to the addition of glucose than soil from the undisturbed and cultivated treatments even when no differences in biomass were detected between the undisturbed and stockpiled soils. It is postulated that the rapidity with which the soil microbial biomass responds to glucose additions may be a sensitive indicator of stress on the soil biological components. The reduction in biomass after storage for 1 year had no adverse effects on the decomposition or primary production potential of the stored soil. Rather, shoot production by fall rye was stimulated in the stored topsoil, presumably a result of better N nutrition.     

Radioresistance of mongolian gerbils. Fast neutrons.

Seventy-six 8 week old Mongolian gerbils were exposed to acute, whole-body fast neutrons produced by The University of Michigan 83-in. cyclotron. Groups of seven or eigth gerbils were given doses between 485 and 881 rad at 25 rad per minute. The LD 50/30 determined by probit analysis was 750 rad, with 95 per cent fiducial limits of 733 and 776. For the 50 per cent mortality level, an r.b.e. of fast neutrons compared with cobalt-60 of 1-45 was determined. For the same end-point, the r.b.e. for fast neutrons compared with X-rays is 1-33. Mortality data, body-weight and microhaematocrit changes are discussed.     

Water relation parameters of the CAM plant Kalanchoë daigremontiana in relation to diurnal malate oscillations

Summary In the CAM plant Kalanchoë daigremontiana, kept in an environmental rhythm of 12 h L: 12 h D in a growth chamber at 60% relative humidity and well watered in the root medium, decreasing water potentials and osmotic potentials of the leaves are correlated with malate accumulation in the dark. In the light increasing water and osmotic potentials ( _W and _S ) are associated with decreasing malate levels. Transpiratory H₂O loss is high in dark and low in light.In continuous light, the CAM rhythm rapidly disappears in the form of a highly damped endogenous oscillation. Malate levels, and water and osmotic potentials of the leaves remain correlated as described above. However, transpiration is very high as malate levels decrease and water and osmotic potentials increase.It can concluded, that water relation parameters like total water potential ( _W ) and osmotic potential ( _S ) change in close correlation with changes of malic acid levels. As an important osmotically active solute in CAM plants, malic acid appears to affect water relations independently of and in addition to transpiration. The question remains open, whether turgor ( _P ) is involved in CAM regulation in intact plants in a similar way as it determines malate fluxes in leaf slices.Abbreviations CAM Crassulacean Acid Metabolism - L Light - D Dark     

Hasel-Pollengehalt der Luft in Mitteleuropa

Jahreszeitliche und tageszeitliche Veränderungen des Haselpollengehalts der Luft nach Untersuchungen aus den Jahren 1967 bis 1972 an elf mitteleuropäischen Meßstellen. Vergleich mit einigen anderen europäischen Daten über den Haselpollengehalt der Luft. In Mitteleuropa kamen die meisten Haselpollen zu Beginn oder gegen Ende des Monats März vor. Stündliche Höchstwerte wurden in den Tag- und Abendstunden gemessen. Morgens kamen keine hohen Stundenwerte vor. Temperaturmessungen lassen vermuten, daß für hohe Haselpollengehalte der Luft in Norddeutschland höhere Temperaturen nötig sind als in südwestdeutschen Gebieten.     

Cold hardiness of the green gemmules of Spongilla lacustris L. (Porifera: Spongillidae)

Most green gemmules of Spongilla lacustris survived enclosure in ice at –20 °C for up to 30 days; however, their rate of germination at 20 °C was less rapid than that of control gemmules. The length of time spent at low temperature had little effect on gemmule survival. In contrast, repeated cooling to –20 °C and warming to 4 °C led to a progressive decline in gemmule viability. These results indicate that cold injury occurs primarily during transitions between high and low temperatures.     

Culture and growth of Lessonia trabeculata (Phaeophyta,Laminariales) juvenile sporophytes in La Herradura de Guayacan Bay,northern Chile

Lessonia trabeculata is one of the major kelps found along the northern coast of Chile. In addition to its ecological and economic importance, L. trabeculata may be severely affected by environmental disturbances such as El Níño, which during 1982–1983 cleared wide areas along the coast of Peru and Chile. The main goal of this work was to mass culture L. trabeculata and to observe the growth of sporophytes obtained in the laboratory and cultured in the sea. Juvenile sporophytes obtained in the laboratory were attached between 1 and 6 m in depth. The linear growth rate, as blade elongation, was recorded weekly for seven months. No significant differences (p < 0.05) were found in sporophyte blade linear growth at different depths. The best elongation growth rate was 7.5 ± 1.6 mm d^–1 at 3 m during March. This preliminary work suggests that L. trabeculata follows an annual growth cycle similar to that of other Laminariales with a high rate of blade elongation during the summer and decreasing towards autumn. This species can be considered a potential candidate for aquaculture to increase the availability of raw material and aid in repopulation of overexploited areas.     

Novel Mutations Affecting a Signaling Component for Chemotaxis of Escherichia coli

The genetic relationship between tsr and cheD mutations, which affect chemotactic ability and map at approximately 99 min on the Escherichia coli chromosome, was investigated. Mutants defective in tsr function typically exhibited wild-type swimming patterns, but were unable to carry out chemotactic responses to a number of attractant and repellent chemicals. In contrast, cheD mutants swam smoothly, with few spontaneous directional changes, and were generally nonchemotactic. In complementation tests, cheD mutations, unlike tsr, proved to be dominant to wild type, suggesting that the cheD defect might be due to an active inhibitor of chemotaxis. Mutations that inactivated the putative inhibitor were obtained by selecting for restoration of chemotactic ability or for loss of cheD dominance. The resultant double mutants were shown to carry the original cheD mutation and a second tightly linked mutation, some of which exhibited nonsense or temperature-sensitive phenotypes, implying that they had occurred in a structural gene for a protein. All such double mutants behaved like typical tsr mutants in all other respects, including complementation pattern, swimming behavior, and chemotactic ability. These findings implied that either overproduction of tsr product or synthesis of an aberrant tsr product was responsible for the chemotaxis defect of cheD strains. Such mutants should be useful in analyzing the role of the tsr product in chemotactic responses.