Migration behaviour and escapement of European silver eels from a large lake and wetland system subject to water level management (Grand‐Lieu Lake,France): New insights from regulated acoustic telemetry data

Current knowledge about the downstream migration of sexually mature European eels (Anguilla anguilla) remains incomplete, particularly in still water habitats such as lakes and wetlands subject to water level management. However, for the management of this endangered species, it is important to understand migration dynamics, and contribution to the breeding stock. This study aimed to assess the parameters that trigger and guide the migration of silver eels in the largest floodplain lake and associated wetlands in France (the sluice regulated Grand‐Lieu Lake). A telemetry survey of 50 acoustic and PIT‐tagged female silver eels was performed during the 2015–2016 migration period. We deployed a novel telemetric approach, using receivers to delimit several restricted virtual boxes to determine the instantaneous location of individuals and to transform simple discrete telemetric data into presence/absence data. The low numbers leaving the lake centre are probably explained by the lack of orienting water flows or other environmental clues, but whilst the fate of 34% (17/50) of the tagged eels is unknown, 18% (9/50) were caught by commercial fishermen. Modelling showed that detections were not clearly associated with environmental factors typically involved in riverine migrations (e.g. current velocity, atmospheric pressure and temperature) but they were particularly associated with higher and increasing water levels and, for eels exiting the lake, a sharp increase when sluice gates were opened to an effective gap of >75 cm. It is concluded that management of water levels and sluice gate opening during the migration period might aid escapement of silver eels.     

Analytical, physiologic, and clinical validation of a radioimmunoassay for measurement of procollagen type III amino terminal propeptide in serum and bronchoalveolar lavage fluid obtained from dogs

OBJECTIVE: To validate a radioimmunoassay for measurement of procollagen type III amino terminal propeptide (PIIINP) concentrations in canine serum and bronchoalveolar lavage fluid (BALF) and investigate the effects of physiologic and pathologic conditions on PIIINP concentrations. SAMPLE POPULATION: Sera from healthy adult (n = 70) and growing dogs (20) and dogs with chronic renal failure (CRF; 10), cardiomyopathy (CMP; 12), or degenerative valve disease (DVD; 26); and sera and BALF from dogs with chronic bronchopneumopathy (CBP; 15) and healthy control dogs (10 growing and 9 adult dogs). PROCEDURE: A radioimmunoassay was validated, and a reference range for serum PIIINP (S-PIIINP) concentration was established. Effects of growth, age, sex, weight, CRF, and heart failure on S-PIIINP concentration were analyzed. In CBP-affected dogs, S-PIIINP and BALF-PIIINP concentrations were evaluated. RESULTS: The radioimmunoassay had good sensitivity, linearity, precision, and reproducibility and reasonable accuracy for measurement of S-PIIINP and BALF-PIIINP concentrations. The S-PIIINP concentration reference range in adult dogs was 8.86 to 11.48 mug/L. Serum PIIINP concentration correlated with weight and age. Growing dogs had significantly higher S-PIIINP concentrations than adults, but concentrations in CRF-, CMP-, DVD-, or CBP-affected dogs were not significantly different from control values. Mean BALF-PIIINP concentration was significantly higher in CBP-affected dogs than in healthy adults. CONCLUSIONS AND CLINICAL RELEVANCE: In dogs, renal or cardiac disease or CBP did not significantly affect S-PIIINP concentration; dogs with CBP had high BALF-PIIINP concentrations. Data suggest that the use of PIIINP as a marker of pathologic fibrosis might be limited in growing dogs.     

Microbiotic soil crusts in the Sahel of Western Niger and their influence on soil porosity and water dynamics

Microbiotic soil crusts are common features of the surface of fallow land in Western Niger. We investigated the interaction between these microbial covers and the porosity and water dynamics of soils at the surface of a Sahelian landscape. The soil pore system was examined by microscopic observations and mercury porosimetry. The soil water retention capacity was measured using a Richard pressure membrane apparatus. Runoff measurements were performed in situ at a 1 m² scale under natural rainfall.     

Present and historical landscape structure shapes current species richness in Central European grasslands

Landscape Ecology - Current diversity and species composition of ecological communities can often not exclusively be explained by present land use and landscape structure. Historical land use may...     

Influence of cucumariosides upon intracellular [Ca2+]i and lysosomal activity of macrophages

Biological effects of the triterpene glycosides, cucumariosides A(2)-2 and A(7)-1 from the edible sea cucumber Cucumaria japonica and their aglycones were investigated using embryos of the sea urchin Strongylocentrotus nudus and the BALB/C line mouse peritoneal macrophages. Cucumariosides were highly cytotoxic in a sea urchin embryo development test with EC(50) values of 0.3 and 1.98 microg/mL, respectively. The aglycone was completely lacking in cytotoxicity. In subtoxic concentrations (0.001-0.1 microg/mL), cucumarioside A(2)-2 showed more then 2-fold stimulation of lysosomal activity and induced a rapid short-term increase in cytosolic Ca(2+) content in mouse macrophages. The maximal stimulatory effect was detected after 1-2 h of cultivation of cells with this glycoside. Cucumarioside A(7)-1 demonstrated more weak effects and even slightly inhibited lysosomal activity, while the aglycone was completely ineffective. At the toxic concentration (1 microg/mL), cucumarioside A(2)-2 induced the sharp irreversable increase of intracellular Ca(2+) concentration. We suggested that cucumariosides, especially A(2)-2, may act as Ca(2+) agonists due to their membranolytic properties.     

Anti-hyperglycemic Effect of Bilberry, Blackberry and Mulberry Ultrasonic Extracts on Diabetic Rats

Small fruits like bilberry, blackberry and mulberry are rich sources of anthocyanins and other phenols, compounds with a certified antioxidant activity and spectacular effects in some chronic diseases. Romanian bilberry, blackberry and mulberry extracts were tested as anti-hyperglycemic agents on diabetic rats. Anthocyanins extraction was carried out with 80 % acidified ethanol in ultrasonically conditions at 23?±?2 °C and 40 kHz. Monomeric anthocyanins content was determined by pH differential method and varied between 1200 and 2800 mg/L. The analyses of anthocyanins were achieved using high performance liquid chromatography and mass spectrometry. Phenolics content was determined by Folin-Ciocalteu procedure and values varied between 2320 and 4250 mg/L gallic acid. Antioxidant activities of extracts were estimated by DPPH scavenging method and the values varied between 8 and 16 miliequivalents Trolox. In order to evaluate the toxicology of the extracts, the heavy metals concentration and pesticides content were analyzed. The extracts were administrated to diabetic rats in drinking water for five weeks. The administration of bilberry extract offered no satisfactory results. Treatment with blackberry extract determined a significant decrease of glucose level from 360 to about 270 mg/dL (p?<?0.05). The mulberry extract administration determined a significant decrease of glucose level from 252 mg/dL at the start day to 155 mg/dL at the final of experiment (p?<?0.05).     

Neuritogenic and Neuroprotective Effects of Polar Steroids from the Far East Starfishes Patiria pectinifera and Distolasterias nipon

The neuritogenic and neuroprotective activities of six starfish polar steroids, asterosaponin Р₁, (25S)-5α-cholestane-3β,4β,6α,7α,8,15α,16β,26-octaol, and (25S)-5α-cholestane-3β,6α,7α,8,15α,16β,26-heptaol (1–3) from the starfish Patiria pectinifera and distolasterosides D₁–D₃ (4–6) from the starfish Distolasterias nipon were analyzed using the mouse neuroblastoma (NB) C-1300 cell line and an organotypic rat hippocampal slice culture (OHSC). All of these compounds enhanced neurite outgrowth in NB cells. Dose-dependent responses to compounds 1–3 were observed within the concentration range of 10–100 nM, and dose-dependent responses to glycosides 4–6 were observed at concentrations of 1–50 nM. All the tested substances exhibited notable synergistic effects with trace amounts of nerve growth factor (NGF, 1 ng/mL) or brain-derived neurotrophic factor (BDNF, 0.1 ng/mL). Using NB cells and OHSCs, it was shown for the first time that starfish steroids 1–6 act as neuroprotectors against oxygen-glucose deprivation (OGD) by increasing the number of surviving cells. Altogether, these results suggest that neurotrophin-like neuritogenic and neuroprotective activities are most likely common properties of starfish polyhydroxysteroids and the related glycosides, although the magnitude of the effect depended on the particular compound structure.