The influence of fitness on neuroendocrine responses to exhaustive treadmill exercise

Neuroendocrine and sympathoadrenal responses to exhaustive graded treadmill exercise were examined in 17 male subjects of varying degrees of fitness. The mean duration of exercise to exhaustion was 15.2 +/- 0.7 (+/- SE) min. Exercise duration was inversely correlated with baseline heart rate (P less than 0.05). Compared to standing baseline values, mean plasma norepinephrine and epinephrine levels increased 339% and 301%, respectively, in an integrated 2-min blood sample collected immediately after completion of exercise. Mean adrenocorticotrophic hormone (ACTH), beta-endorphin (beta-EP), beta-lipotropin (beta-LPH), and prolactin levels increased 282%, 720%, 372%, and 211%, respectively, in an integrated 4-min blood sample beginning 2 min after completion of exercise. Cortisol levels increased 183% in the sample collected 17-21 min after exercise. The magnitude of these neuroendocrine responses to exercise was similar among individuals at the same relative intensity of exhaustive exercise, regardless of the duration of exercise. The exercise-induced increases of the pro-opiomelanocortin (POMC)-derived peptides, ACTH, beta-EP, and beta-LPH, were highly correlated with each other (P values less than 0.001), and were correlated with prolactin increases, (P values less than 0.05). During a 20-min recovery period after exercise, changes in heart rate, ACTH, and beta-LPH levels were correlated with duration of exercise, (P less than 0.01, P less than 0.03, and P less than 0.03, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Asymmetric fusion between protoplasts of tomato (Lycopersicon esculentum Mill.) and gamma-irradiated protoplasts of potato (Solanum tuberosum L.): the effects of gamma irradiation

This paper describes the aggregation of nuclei in heterokaryons of tomato and unirradiated or irradiated potato protoplasts and the effects of gamma irradiation of potato and tomato protoplasts on single- and double-stranded DNA fragmentation, DNA repair and DNA synthesis as revealed by alkaline and pulsed field gel electrophoresis and an immunocytochemical technique. The prospects for obtaining highly asymmetric somatic hybrids of tomato and gamma-irradiated potato are discussed.     

Laboratory scale enclosure: concept, construction and operation

A laboratory scale enclosure (LSE) was devised for studyingthe seston dynamics in shallow, wind-mixed lakes. The LSE isa continuous flow system suitable for mass balance studies oflake water columns, and for cultivation of phytoplankton speciesas a reference for potential growth at the lake's light andmixing regime. The construction of the LSE is described in detail.Results are given on the operation with water from Lake Loosdrecht(The Netherlands). The coefficient of vertical mixing in theLSE was variable from 7.6 to 25.6 cm² s^–1, i.e. similarto values reported for shallow, wind-exposed lakes. On average,the vertical light attenuation and the spectral changes withdepth in the LSE agreed well with the in situ underwater lightclimate. Mass balances for phosphorus and oxygen could be accuratelyestablished, while the loss of paniculate matter due to settlingand wall growth was insignificant. The LSE may also be appliedas an incubator for primary production measurements in a ‘natural’light gradient and allowed prolonged continuous cultivationof Prochlorothrix hollandica.     

L'espace minéral au Paléolithique moyen dans le Sud du Massif central : premiers résultats pétroarchéologiques

The Middle Palaeolithic mineral environment in the South of the Massif Central: preliminary petroarchaeological results. Five Middle-Palaeolithic assemblages coming from archaeological sites in the Haute-Loire and Ardèche dated to isotopic stages 7 to 5 have been studied using a petroarchaeological method based on the optimization of observation techniques at different scales with respect to genetic and postgenetic characteristics of flint raw materials. The method reveals a relatively large collection area for the middle mountain sites (Sainte-Anne I, Baume-Vallée, Le Rond-de-Saint-Arcons, Rochelimagne), but apparently a smaller one for the site of Payre, located nearby the side of the Rhône Valley. For all sites, gathering is predominantly local, but some distant sources are utilised too. The rare exogenous materials, for example the Bedoulian flint from Ardèche identified in the Velay assemblages (Sainte-Anne I, Baume-Vallée) are in fact located in the heart of the massif as well as in secondary deposits and thus do not allow one to establish firm circulation routes for, or certain contact between the relevant human groups. To cite this article: P. Fernandes et al., C. R. Palevol 5 (2006).     

Cryptic speciation in the field vole: a multilocus approach confirms three highly divergent lineages in Eurasia

Species are generally described from morphological features, but there is growing recognition of sister forms that show substantial genetic differentiation without obvious morphological variation and may therefore be considered ‘cryptic species’. Here, we investigate the field vole (Microtus agrestis), a Eurasian mammal with little apparent morphological differentiation but which, on the basis of previous sex‐linked nuclear and mitochondrial DNA (mtDNA) analyses, is subdivided into a Northern and a Southern lineage, sufficiently divergent that they may represent two cryptic species. These earlier studies also provided limited evidence for two major mtDNA lineages within Iberia. In our present study, we extend these findings through a multilocus approach. We sampled 163 individuals from 46 localities, mainly in Iberia, and sequenced seven loci, maternally, paternally and biparentally inherited. Our results show that the mtDNA lineage identified in Portugal is indeed a distinct third lineage on the basis of other markers as well. In fact, multilocus coalescent‐based methods clearly support three separate evolutionary units that may represent cryptic species: Northern, Southern and Portuguese. Divergence among these units was inferred to have occurred during the last glacial period; the Portuguese lineage split occurred first (estimated at c. 70 000 bp ), and the Northern and Southern lineages separated at around the last glacial maximum (estimated at c. 18 500 bp ). Such recent formation of evolutionary units that might be considered species has repercussions in terms of understanding evolutionary processes and the diversity of small mammals in a European context.