The partitioning of carbohydrates and the biomass of leaves in Populus tremula L . canopy

 This study was aimed at making a quantitative evaluation of the biomass, carbohydrates and mineral nutrients partitioning in the canopy of aspen (Populus tremula L.) growing in a forest stand. Tree canopy biomass was divided into ten equal horizontal layers and the material for the study was sampled from all canopy layers. The results indicated that the specific leaf mass and the dry matter content increased but the area of leaves decreased toward the top of the canopy. The content of the non-structural carbohydrates depended largely on the position of the leaves in the canopy and the N, P and K contents in the leaves, reaching a maximum in the upper canopy layers better exposed to light. Regression analysis showed a linear relationship between the leaf mass per area and the percentage of dry matter on the one hand and the content of carbohydrates, N, P and K in the canopy on the other. Received: 11 March 1997 / Accepted: 16 June 1997     

Is the brown shrimp Crangon crangon (L.) population of the Vaccarès lagoon (Camargue, France, Rhône delta) an annual population?

To study the population dynamics of Crangon crangon in the Vaccarès lagoon in the Camargue (Rh?ne delta), the age of brown shrimp was determined using the method of Tiews (1954). This method consists in counting the number of segments of the outer branch of the first antenna. This number is correlated with the number of moults already accomplished by the shrimp. The duration of the intermoult depends on water temperature. Adapting this model to our environmental data, we determined the age of the brown shrimp. Hatching of larvae occurs in the sea in May, and juveniles enter the lagoon from June to September. Our results showed that Crangon crangon in the Vaccarès lagoon reached sexual maturity between 6 and 11 months, and individuals are 1 year old when they leave the lagoon. A few adults from the previous year (1+) migrate back to the lagoon the following year, but these older individuals represent only a very small part of the population, and have only been observed occasionally. The Vaccarès brown shrimp population can therefore be considered as annual, in contrast to northern European populations.     

Distribution,population density,and status of sympatric cercopithecids in the Campo-Ma’an area,southwestern cameroon

A study on species composition, distribution, and population density of cercopithecids in the Campo-Ma’an area, Southwestern Cameroon, was undertaken from December 1997 until August 2000. A total of 665.5 km of line transects was used for the census. Thirteen diurnal primate species including five endangered species (Gorilla g. gorilla, Pan troglodytes, Mandrillus sphinx, Colobus satanas, Cercocebus torquatus) were recorded in the Campo Forest, the greatest part of which is a logging concession.Cercopithecus nictitans (1.43 groups/km²),C. cephus (1.13 groups/km²),C. pogonias (0.81 groups/km²), andC. torquatus (0.51 groups/km²) occurred at medium frequencies compared to figures from other Central African study sites. Mandrill densities estimated (0.27 groups/km²) show that the area is very important for the conservation of this rare species. Guenon densities found inside areas with a high level of human activities did not differ significantly from densities estimated in areas with a lower level of human activities.C. torquatus densities were significantly higher in the areas with a low level of human disturbance and encounter rates withLophocebus albigena also indicate a preference of less disturbed areas. Mangabeys are thus likely to be adversely affected by human activities in the area. In the Ma’an Forest, which has not been logged yet, ten species were confirmed. The population densities of two guenons (C. nictitans andC. cephus) were estimated to be twice as high in the unlogged forest area as compared to the logged forest of Campo. Other species are rarer in the Ma’an Forest than in the Campo Forest. Although mangabeys are adversely affected by human activities, the results still indicate that selective logging may be compatible with the conservation of cercopithecids, if a reduced damage logging concept and antipoaching measures are implemented. Increased hunting activities following logging operations will definitely have a negative longterm impact on primate populations in the Campo-Ma’an area if no further, more effective conservation measures will regulate wildlife use in future.     

Current status of the habitat and population of the black howler monkey (Alouatta pigra) in Balancán, Tabasco, Mexico

We evaluated the habitat and populations of the black howler monkey (Alouatta pigra) in the municipality of Balancán, Tabasco, southeastern Mexico, using a combination of field surveys and remotely sensed data. We identified 21,937 ha of remnant vegetation composed of 1,348 fragments. Fragments separated by up to 200 m were grouped into "clusters" of fragments in accordance with the maximum observed open distance crossed by A. pigra. A total of 11% or 84 of the 772 clusters identified through remote sensing were selected at random, and for these we determined the vegetation type, canopy height, area, and distance to the closest human settlement. In these same 84 clusters, which included a total area of 9,817 ha, from October to June of 2006 we located a total of 1,064 black howler monkeys, including 228 troops and 49 solitary monkeys. A. pigra was found in 62 (74.7%) of all clusters visited, with a cumulative area of 6,032 ha. Troops varied in size from 2 to 15 individuals (average 6.0+/-2.9 ind/troop). Adults were 67% (n=716) of detected individuals, whereas juveniles were 20.5% (n=218) and infants were 12.5% (n=133). We found black howlers to occur at an ecological density of 10.8 ind/km(2), which is low in comparison with A. pigra in other fragmented and conserved sites. We found a statistically significant relationship between the area of clusters and the abundance of howler monkeys (r(2)=0.2, F=10.47, gl=3, P=0.002). In addition, the probability of finding A. pigra was greater in secondary vegetation, riparian vegetation, tropical dry forest, undisturbed tropical oak forest, and palm forest (F=12, gl=3, P<0.0001), as compared with disturbed tropical oak forest. Our results provide data on the distribution, abundance, and population structure of black howler monkeys in a fragmented landscape in the southeast of Mexico. These data are a necessary prerequisite for conservation planning for this species.     

Distribution in space and time of Cladocera (Crustacea) in the alluvial sediments of the river Rhône (France)

Two stations in a polluted section of the Rhône River downstream of Lyon (France) were investigated during a five month' period. The samples (101 water and sediment) were taken by the Bou-Rouch method at 20, 50 and 100 cm depth in the sediments and at three different distances from the waterline. Twenty-six Cladocera species, belonging to five families were found. Most of them are known to live in the Rhône River system, as well in the surface water as in the underflow. Their community structure and the time and space distribution are described and discussed in relationship with other macroinvertebrate taxa and with the oxygen content of the pumped water.

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Zusammenfassung Zwei Probennahmestellen in einem stark verschmutzten Flußabschnitt der Rhône unterhalb von Lyon (Frankreich) wurden über einen Zeitraum von fünf Monaten untersucht. Die Proben (10 l Wasser und Feinsedimente) wurden mit einer Bou-Rouch-Pumpe in 20, 50 and 100 cm Tiefe im Kiesschotterbett und in drei verschiedenen Entfernungen vom Rhôneufer entnommen. Sechsundzwanzig Cladoceren-Arten aus fünf Familien wurden gefunden. Ihre Faunenzusammensetzung und die räumliche und zeitliche Verteilung wurden beschrieben und im Vergleich zu anderen gefundenen Macroinvertebraten-Taxa und zum Sauerstoffgehalt des Interstitial-Wassers diskutiert.

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Résumé Deux stations dans une zone polluée du Rhône en aval de Lyon (France) ont été étudiées pendant une période de cinq mois. Les échantillons (10 l d'eau et de sédiment) ont été pris avec la méthode selon Bou et Rouch à des profondeurs de 20, 50 et 100 cm dans les sédiments et à trois distances différentes du bord de l'eau. Vingt-six espèces de Cladocères appartenant à cinq familles ont été trouvées. La plupart d'entre elles sont déjà connues dans l'hydrosystème du Rhône, aussi bien en surface que dans le sous-écoulement. Leur structure de peuplement et leur distribution spatio-temporelle sont décrites et discutées en relation avec les autres taxons de macroinvertébrés trouvés trouvés et avec la concentration en oxygène de l'eau interstitielle.

     

Leptin role in advanced lung cancer. A mediator of the acute phase response or a marker of the status of nutrition?

Leptin is an anorexia inductor peptide produced by adipocytes and related to fat mass. Leptin is also produced by fat under proinflammatory cytokine action. Our objective is to study serum leptin levels in relation to nutritional status and acute phase response in advanced-stage non-small cell lung cancer.Seventy-six patients newly diagnosed of non surgical non-small cell lung cancer before chemotherapy treatment and 30 healthy controls were included. BMI, serum leptin and cholesterol levels and lymphocyte count were decreased in lung cancer patients. Cytokine IL-6, TNF-alpha, sTNF-RII, sIL-2R, IL-12, IL-10 and IFN-gamma, and other acute phase reactants as alpha1 antitrypsin, ferritin, CRP and platelets were all raised in patients, whereas the IL-2 was decreased. We found a direct relationship between leptin and other indicators of the status of nutrition, especially total fat mass. We also found a close relationship between the status of nutrition and the performance status (Karnofsky index). However, serum leptin and nutritional status were inversely correlated with acute phase proteins and proinflammatory cytokines, suggesting a stress-type malnutrition. Although serum leptin levels, nutritional status and Karnofsky index are related to survival, at multivariate analysis they all were displaced by the acute phase reaction markers.These results suggest that cancer anorexia and cachexia are not due to a dysregulation of leptin production. Circulating leptin concentrations are not elevated in weight-losing cancer patients and are inversely related to the intensity of the inflammatory response. In advanced lung cancer patients serum leptin concentrations only depend on the total amount of fat.     

Dynamics of seston constituants in the Ariège and Garonne rivers (France)

Water contents of suspended matter, algal pigments, particulate organic carbon and particulate phosphorus were measured in the rivers Garonne (2 sites) and Ariège (1 site) throughout an annual cycle. The general trend of the parameters was similar at the three sites. Depending on the sites, the period of algal growth (chlorophyll a + phaeopigments > 25 µg l^–1), lasted from two to six weeks in August–September. The algal peaks reached 50 to 90 µg 1^–1 of total pigments. High contents of particulate organic carbon (> 2 mg 1^–1) occurred at the end of summer (coinciding with algal growth), and during the November and May floods. In summer 50–75 % of the suspended matter was organic, in spring this was 10 times less. The high linear correlation between particulate organic carbon and pigment contents (r = 0.87; P = 0.0001) suggested an algal origin of at least part of the particulate carbon. Algal carbon was minor in the annual fluxes of particulate carbon (25 to 39% depending on the sites), but relatively high in comparison with other rivers. The mean particulate phosphorus content calculated over the year was 24 µg l^–1 ; it varied from 15 µg l^–1 during the high water period to 28 µg 1^–1 during the low water period. Likewise the percentage of particulate phosphorus in the suspended matter varied from 0.17 to 0.40. A negative linear correlation existed between particulate phosphorus content and specific discharge (r = – 0.46; P = 0.0001).The very marked seasonal trend of the parameters and the interactions led us to differentiate two modes of the rivers' functioning: a hydrologic phase and a biological phase. The hydrologic phase (high water) was dominated by the processes of erosion and transfer over the whole catchment area and the flood plain, while the biological phase was characterized by a high primary production in the river bed.     

Crystal structures of an Extracytoplasmic Solute Receptor from a TRAP transporter in its open and closed forms reveal a helix-swapped dimer requiring a cation for α-keto acid binding

Background  

The import of solutes into the bacterial cytoplasm involves several types of membrane transporters, which may be driven by ATP hydrolysis (ABC transporters) or by an ion or H⁺ electrochemical membrane potential, as in the tripartite ATP-independent periplasmic system (TRAP). In both the ABC and TRAP systems, a specific periplasmic protein from the ESR family (Extracytoplasmic Solute Receptors) is often involved for the recruitment of the solute and its presentation to the membrane complex. In Rhodobacter sphaeroides, TakP (previously named SmoM) is an ESR from a TRAP transporter and binds α-keto acids in vitro.     

Seston dynamics and bivalve feeding in the Bay of Marennes-Oléron (France)

Within the framework of an investigation into the carrying capacity of the Bay of Marennes-Oléron (France) for bivalve culture, thein situ uptake of suspended particulate material by oysters (Crassostrea gigas) and mussels (Mytilus edulis) was determined in experiments with benthic ecosystem tunnels. Very high fluctuations in seston quantity and quality were observed within and between tidal cycles. The percentage of organic carbon was inversely related to seston quantity at low concentrations. Organic carbon was diluted by resuspension of material rich in inorganic matter. At high seston concentrations a constant level of about 2% organic carbon was found. The C/N ratio was relatively constant throughout the seasons and fairly low (6.5 to 8.4). Owing to the presence of bivalves large fluxes of suspended particulate material were observed in thein situ measurements. Selective retention of organic carbon or nitrogen could not be demonstrated. Clearance rates based on chlorophyll uptake were within a normal range compared to other studies. A large contribution to the food of the bivalves seemed to be formed by resuspended microphytobenthos. Judged by the low C/N ratio, the food was of good quality. Although its quantity was variable by dilution, it may support largely the carrying capacity of the Bay of Marennes-Oléron for the cultivation of bivalves. Communication no. 687 of the Netherlands Institute of Ecology, Centre for Estuarine and Coastal Ecology, Yerseke, the Netherlands.     

Does habitat use and ecological niche shift over the lifespan of wild species? Patterns of the bearded vulture population in the Western Alps

We analysed bearded vulture (Gypaetus barbatus) occurrences collected through long-term monitoring (from 1993 to 2010) in the Western Alps (1) to test whether ecological niches shift due to individual development and (2) to verify whether these patterns could reflect their spatial distribution. Thus, we compared the distribution patterns of three age classes (‘young’, ‘sub-adults’ and ‘adults’) through the K-select analysis. We then computed ten species distribution models (SDMs) and their average prediction to test for differences in age class distribution. The K-select analysis showed highly significant differences in the ecological niche among all the age classes and we also found highly significant differences in all the SDMs among the three age classes considered. Our results quantitatively showed that target species exhibits age specific shifts in the ecological niche and changes in the spatial distribution of individuals. Our methods are potentially widely applicable for testing differences among age classes of other species and thus, defining the best conservation actions (such as re-introduction) by taking into account different requirements in different stages of the individuals’ life.     

Heterogeneity and typology of fish habitat in the main stream of a Breton coastal river (Elorn-Finistère,France)

Hydrobiologia - To study the salmonids potential production of a coastal river main stream from simple characterization of the fish habitat, it was necessary to rate the hydrosystem's spatial...     

Isozyme polymorphism and genetic structure of the population of Sorbus torminalis (L.) Crantz from the Bytyń Forest (Poland)

Dormant buds collected from 35 wild service trees (Sorbus torminalis) in the Bytyń Forest were tested with horizontal gel electrophoresis to assess the genetic structure of the population. Among 16 investigated isozyme loci, seven loci (ADH-A, 6PGD-A, GDH-B, ME-A, SOD-A, PGM-A, PGM-B) proved to be polymorphic, whereas the other nine loci (SDH-A, SDH-B, DIA-C, DIA-D, FLE-A, FLE-B, GOT-B, IDH-A, IDH-B) were monomorphic. The number of alleles per polymorphic locus ranged from two to three, with a mean of 2.29. The average observed and expected heterozygosities were 0.2665 and 0.3462, respectively. The combined FIS value over all polymorphic loci was 0.2179, which reflects a substantial deficit of heterozygotes. Two polymorphic loci (SOD-A, PGM-A) were identified in S. torminalis for the first time.     

α1 (Pi) types and subtypes in the Tyrolean population

Since nine patients with infantile liver cirrhosis or hepatopathy associated with the Pi ZZ phenotype had been observed in recent years in the Children's Hospital of the University of Innsbruck, Tyrol, the distribution of the Pi types and the PiM subtypes was determined in the Tyrolean population. Apparently healthy blood donors (868) from different regions of Tyrol were examined. Isoelectricfocusing was used for classification of Pi types. The frequency of the allele PiZ was 0.0138, which corresponded to the range observed in other Middle European populations. The frequencies for the suballeles of PiM were PiM1 = 0.7062, PiM2 = 0.1480, and PiM3 = 0.1037. PiS had a frequency of 0.0225, the other rare alleles occurred with a combined frequency of 0.0058.     

Thermal constant of an experimental population of Muscina stabulans (Fallén 1817) (Diptera:Muscidae) in the laboratory

A study was conducted to investigate the thermal constant in an experimental population of Muscina stabulans (Fallén 1817). A natural population was obtained from a livestock and their F1 generations were maintained at four constant temperatures (16 degrees C, 20 degrees C, 26 degrees C and 31 degrees C). The thermal constant was calculated by the hyperbole method using the base temperature, tb = 4.4 degrees C and the thermal constant K = 35.3 GD. Ricker's geometric regression, considering tb = 7.8 degrees C and K = 28.9 GD was also calculated.