Role of concentric force in limiting improvement in muscular strength

We hypothesized that resistance training with combined eccentric and concentric actions, and concentric action only, should yield similar changes in muscular strength. Subjects in a free weight group trained three times a week for 12 wk with eccentric and concentric actions (FW, n = 16), a second group trained with concentric-only contractions using hydraulic resistance (HY; n = 12), and a control group did not train (n = 11). Training for FW and HY included five sets of supine bench press and upright squat at an intensity of 1-6 repetition maximum (RM) plus five supplementary exercises at 5-10 RM for a total of 20 sets per session for approximately 50 min. Testing at pre-, mid-, and posttraining included 1) 1 RM bench press and squat with and 2) without prestretch using free weights; 3)isokinetic peak force and power for bench press and squat at 5 degrees/s, and isotonic peak velocity and power for bench press with 20-kg load and squat with 70-kg load; 4) hydraulic peak bench press force and power, and peak knee extension torque and power at fast and slow speeds; and 5) surface anthropometry (fatfolds and girths to estimate upper arm and thigh volume and muscle area). Changes in overall fatness, muscularity, and muscle + bone cross-sectional area of the limbs did not differ between groups (P greater than 0.05). Improvements in free weight bench press and squat were similar (P greater than 0.05) in FW (approximately 24%) and HY (approximately 22%, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of agents affecting Ca2+ homeostasis onTrichoderma viride growth and conidiation

Agents known to influence Ca²⁺ homeostasis affected significantly the vegetative growth and starvation-induced conidiation ofTrichoderma viride. Ca²⁺ in millimolar concentrations stimulated both growth and conidiation; a Ca²⁺ deprivation of the fungus by the chelation of extracellular Ca²⁺ (not Mg²⁺ or divalent trace metals) with EGTA (ethyleneglycolbis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid) restricted both the vegetative growth rate and starvation-induced conidiation. Both processes were affected by either Ca²⁺ or EGTA with different efficiencies. Divalent cations (Sr²⁺, Ba²⁺, Co²⁺, Ni²⁺, Mg²⁺, Cd²⁺, Cu²⁺, Mn²⁺) and La³⁺ (inorganic Ca²⁺ blockers) in millimolar concentrations exerted complex (stimulatory, inhibitory, or biphasic) effects on growth and conidiation. In general, their effects on the two processes were mutually different either qualitatively, or quantitatively, or both. Organic Ca²⁺ antagonists (verapamil and dihydropyridines) inhibited the vegetative growth. The results show that Ca²⁺ is required for vegetative growth and conidiation, and that different Ca²⁺-dependent mechanisms may be involved in the two processes. Divalent cations could serve as a tool for investigating the relationship between growth and conidiation.     

Molecular evidence of a lignin peroxidase H8 homologue inFusarium oxysporum

We describe an evidence for the existence of a ligninase isoenzyme H8 in the deuteromyceteFusarium oxysporum on the genomic as well as on the RNA level.     

Replication banding in the chromosomes of the European eel (Anguilla anguilla)

The chromosomes of the European eel Anguilla anguilla have been analyzed with a replication banding technique from lymphocyte cultures treated with 5-BrdU. This technique allows us to identify with high resolution the individual chromosome pairs and to differentiate classes of chromatin by the order of replication. The replication banding obtained on the chromosomes of European eel can be related with the structural bands described in this species.     

Three fluorescent probes for the flow-cytometric assessment of membrane potential inSaccharomyces cerevisiœ

Three fluorescent probes, tetramethyl rhodamine ethyl ester (TMRE), 3,3′-dipropylthiacarbocyanine iodide (diS-C₃(3)) and 3,3′-dipropyloxacarbocyanine iodide (diO-C₃(3)), were tested for their suitability as fluorescent indicators of membrane potential inSaccharomyces cerevisiœ in studies performed by flow cytometry. For all these dyes the intensity of fluorescence of stained cells increased with probe concentration in the range of 60–3000 nmol/L. The optimum staining period was 15–20 min for diS-C₃(3). Depolarization of cells by increased extracellular potassium level and by valinomycin elicited with all probes a drop in fluorescence intensity. In some yeast batches this depolarization was accompanied by a separation of subpopulations with different fluorescence properties.     

Vanadate inhibits the production and/or release of secondary metabolites without impairing growth in several fungal species

Vanadate (NaVO₃) in concentrations between 0.1–3.0 mmol/L inhibited the production of secondary metabolites (SMs) of strains of the following species:Trichoderma viride, Penicillium purpurogenum, Penicillium citrinum, Talaromyces avellaneus, andVerticillium psalliotœ. Growth was either not affected by NaVO₃, or the inhibition of the SM production occurred at lower NaVO₃, concentrations than that of the growth. Thus, at some NaVO₃ concentration the SM production was inhibited but the growth remained unaffected. The results suggest that NaVO₃ exerts a specific action either on the SM biosynthetic pathway(s) or on the export of SMs from cells.     

Inhibition ofPseudomonas aeruginosa alginate expression by subinhibitory concentrations of antibiotics

The effects of subinhibitory concentrations (1/4, 1/8, 1/16 of the MIC) of quinolones (ciprofloxacin, enoxacin, nalidixic acid, norfloxacin, ofloxacin, pefloxacin), aminoglycosides (amikacin, gentamicin, netilmicin, streptomycin, tobramycin), β-lactams (aztreonam, ceftazidime, imipenem, ticarcilin) and macrolides (erythromycin, roxitromycin) on the excretion of alginate by aP. aeruginosa strain were studied. Both β-lactam and macrolide antibiotics were found ineffective at the concentrations tested, except erythromycin and imipenem at 1/4 MIC. Aminoglycosides at a concentration of 1/4 MIC reduced most effectively the excretion of alginate. Quinolones were also effective at this sub-MIC; 1/16 MIC was ineffective with all antibiotics or stimulated the production of alginate.     

Organellar DNA restriction fragment length polymorphism (RFLP) and nuclear random amplified polymorphic DNA (RAPD) analyses of morphotypes of Gracilaria (Gracilariales,Rhodophyta) from Chile

The extreme phenotypic variability recognized among the species of Gracilaria has highlighted the need for the application of refined methods to help solve taxa identifications. In Chile, there still exists uncertainty about the exact number of Gracilaria species. Our investigations are centered on DNA analyses of morphotypes collected from different geographical locations, namely Lenga and Isla Santa María, Region VIII (36°00 S to 38°00 S), and Maullín, Region X (39°30 S to 43°40 S). These two regions of Chile are considered as areas of confluence of G. chilensis, G. verrucosa, and a species of Gracilariopsis. In this study four morphotypes, from a natural bed located in Maullín, were analyzed for RFLP of plastid DNA and the results compared with data of four morphotypes from a bed in Lenga. The DNA banding patterns from each enzyme digest were identical irrespective of morphotypes and/or locations. In an attempt to unravel the nature of the morphological differences found among Lenga and Maullín morphotypes, RAPD analyses of nuclear DNA were also performed; however, no polymorphism has been found yet. Therefore, the data of this study, as well as concurrent data from preliminary interfertility tests, suggest that all morphotypes belong to a single taxon, Gracilaria chilensis.Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas     

Statistical analysis for the spatial validity of a model to forecast the daily number of forest fires

In earlier papers a qualitative and quantitative model was developed for predicting the number of forest fires occurring per day. This model permits the forecast at 00.00 hours Universal Time Convention (UTC) of any day (d), the number of forest fires per day for a range of several days (d tod+5) over a particular region. Input data are the number of forest fires in the region during two preceding days (d–2 andd–1) and the type of day (real and evaluated from radiosonde ford–2,d–1,d and predicted from meteorological medium-range forecasts, i.e. of European Centre, ford+1,d+2,d+3,d+4 andd+5. As this model requires data obtained by radiosonde, particularly temperatures and geopotentials at 850 and 700 hPa and dew points (or specific humidity) at 850 hPa, this study investigates the spatial validity of the model in relation to the distance from the radiosonde station (RS). The highest quality forecast is obtained for the region immediately surrounding the RS, and diminishes with increasing distance from it, this being due to the data obtained from the RS not being representative of the atmospheric column over the region. Hence, the derivation of the critical distance for a particular quality level of measurement. Conversely, fixed quality level implies a specific separation between RS and the region for the prediction, with a higher predictive quality implying a shorter distance.