Effect of recreational-fisheries management on fish biodiversity in gravel pit lakes,with contrasts to unmanaged lakes

Gravel pit lakes are novel ecosystems that can be colonized by fish through natural or anthropogenic pathways. In central Europe, many of them are managed by recreational anglers and thus experience regular fish stocking. However, also unmanaged gravel pits may be affected by stocking, either through illegal fish introductions or, occasionally, by immigration from connected water bodies. We sampled 23 small (< 20 ha) gravel pit lakes (16 managed and 7 unmanaged) in north-western Germany using littoral electrofishing and multimesh gillnets. Our objective was to compare the fish biodiversity in gravel pit lakes in the presence or absence of recreational fisheries. Given the size of the sampled lakes, we expected species poor communities and elevated fish diversity in the managed systems due to regular stocking of game fish species. Our study lakes were primarily mesotrophic and did not differ in key abiotic and biotic environmental characteristics. Lakes of both management types hosted similar fish abundances and biomasses, but were substantially different in terms of fish community structure and species richness. Fish were present in all lakes, with a minimum of three species. Higher α-diversity and lower β-diversity was discovered in managed gravel pit lakes compared to unmanaged lakes. Consequently, recreational-fisheries management fostered homogenization of fish communities, by stocking a similar set of fish species desired by anglers such as piscivorous fish and large bodied cyprinids. However, unmanaged gravel pit lakes were also affected by human-mediated colonization, presumably by illegal fish releases. Hardly any non-native species were detected, suggesting that recreational-fisheries management did not foster the spread of exotic species in our study region.     

The cyclin B2 component of MPF is a substrate for the c-mos(xe) proto-oncogene product

Previous studies from this laboratory have shown that purified MPF from Xenopus eggs contains cyclin B2 complexed with cdc2 kinase. The activation of MPF during oocyte maturation is known to require expression of the c-mos(xe) proto-oncogene. We show here that immunoprecipitates of either v-mos from Moloney murine sarcoma virus-transformed NIH 3T3 cells or c-mos from Xenopus eggs phosphorylate cyclin B2 in vitro. Phosphopeptide analysis reveals a pattern similar to that observed with cdc2 kinase. Moreover, ablation of c-mos(xe) from oocytes by antisense oligonucleotide injection reduces the rate of cyclin B2 phosphorylation in oocyte extracts by 40%. These results suggest that the mechanism of activation of MPF by c-mos(xe) involves phosphorylation of the cyclin component.     

Performance Assessment of Two Whole-Lake Acoustic Positional Telemetry Systems - Is Reality Mining of Free-Ranging Aquatic Animals Technologically Possible?

Acoustic positional telemetry systems (APTs) represent a novel approach to study the behaviour of free ranging aquatic animals in the wild at unprecedented detail. System manufactures promise remarkably high temporal and spatial resolution. However, the performance of APTs has rarely been rigorously tested at the level of entire ecosystems. Moreover, the effect of habitat structure on system performance has only been poorly documented. Two APTs were deployed to cover two small lakes and a series of standardized stationary tests were conducted to assess system performance. Furthermore, a number of tow tests were conducted to simulate moving fish. Based on these data, we quantified system performance in terms of data yield, accuracy and precision as a function of structural complexity in relation to vegetation. Mean data yield of the two systems was 40 % (Lake1) and 60 % (Lake2). Average system accuracy (acc) and precision (prec) were Lake1: acc = 3.1 m, prec = 1.1 m; Lake2: acc = 1.0 m, prec = 0.2 m. System performance was negatively affected by structural complexity, i.e., open water habitats yielded far better performance than structurally complex vegetated habitats. Post-processing greatly improved data quality, and sub-meter accuracy and precision were, on average, regularly achieved in Lake2 but remained the exception in the larger and structurally more complex Lake1. Moving transmitters were tracked well by both systems. Whereas overestimation of moved distance is inevitable for stationary transmitters due to accumulation of small tracking errors, moving transmitters can result in both over- and underestimation of distances depending on circumstances. Both deployed APTs were capable of providing high resolution positional data at the scale of entire lakes and are suitable systems to mine the reality of free ranging fish in their natural environment. This opens important opportunities to advance several fields of study such as movement ecology and animal social networks in the wild. It is recommended that thorough performance tests are conducted in any study utilizing APTs. The APTs tested here appear best suited for studies in structurally simple ecosystems or for studying pelagic species. In such situations, the data quality provided by the APTs is exceptionally high.     

Relationships of lipocalin 2 with breast tumorigenesis and metastasis

Breast cancer is one of the most common cancers in women worldwide and accounts for one‐sixth of cancer deaths in the United States. Breast cancer consists of a heterogeneous group of tumours classified into five types, in which the HER2/neu positive and the basal type (most are ER and HER2 negative) have the worst clinical prognosis. In recent years, prognostic/predictive markers such as ER/PR or HER2/neu have been widely used in the selection of the optimal breast cancer treatments for individual patients, which have been proven to be very effective in disease control. These results suggest that further examination of the molecular mechanisms underlying the breast tumorigenesis and identification of the potential biomarkers in different types of breast cancers will greatly benefit clinical diagnosis and facilitate the design of more effective personalized therapies to increase patient survival. This review aims to summarize recent research findings on lipocalin 2 (LCN2), a newly identified biomarker and a potential therapeutic target for breast cancer, and the possible mechanisms underlying its role in tumorigenesis and metastasis. J. Cell. Physiol. 226: 309–314, 2011. © 2010 Wiley‐Liss, Inc.     

c-Abl Activates Janus Kinase 2 in Normal Hematopoietic Cells

Jak2 is involved in cytokine growth factor-stimulated signal transduction, but the mechanism of its activation is largely unknown. Here, we investigated Jak2 activation in a normal hematopoietic cell line, 32D mouse myeloid cells. The bimolecular fluorescence complementation studies showed that c-Abl formed a stable complex with Jak2 in live cells. Co-immunoprecipitation results showed that c-Abl bound to the βc chain of IL-3/IL-5/GM-CSF receptors. The kinase activities of both c-Abl and Jak2 were stimulated by IL-3 in 32D cells. Decreasing c-Abl protein expression in 32D cells by inducible shRNA decreased Jak2 activity and resulted in the failure of Jak2 activation in response to IL-3. Treatment of IL-3 and serum-starved 32D cells with 1 μm imatinib mysylate inhibited IL-3 stimulated kinase activities of both c-Abl and Jak2. In addition, the kinase-deficient Bcr-Abl mutant (p210K1172R) was defective for activation of Jak2 in 32D cells and impaired IL-3 independent growth, which was rescued by overexpression of c-Abl (+Abl). IL-3 efficiently inhibited apoptosis of 32Dp210K/R+Abl cells induced by imatinib mysylate but not Jak2 kinase inhibitor TG101209. In summary, our findings provide evidence that the kinase function of c-Abl and its C-terminal CT4 region is crucial for its interaction with Jak2 and its activation. c-Abl kinase activity induced by IL-3 is required for IL-3-stimulated Jak2 and Jak1 activation. Our findings reveal a novel regulatory role of c-Abl in Jak2 activation induced by IL-3 cytokine growth factor in 32D hematopoietic cells.     

Environmental determinants of fish abundance in the littoral zone of gravel pit lakes

Hydrobiologia - The type and extent of habitats along the shoreline specify the distribution of fish in the littoral zone of lakes, but effects are likely species and size-specific and might be...     

Technological innovations in the recreational fishing sector: implications for fisheries management and policy

Reviews in Fish Biology and Fisheries - Technology that is developed for or adopted by the recreational fisheries sector (e.g., anglers and the recreational fishing industry) has led to rapid and...     

Consistent Selection towards Low Activity Phenotypes When Catchability Depends on Encounters among Human Predators and Fish

Together with life-history and underlying physiology, the behavioural variability among fish is one of the three main trait axes that determines the vulnerability to fishing. However, there are only a few studies that have systematically investigated the strength and direction of selection acting on behavioural traits. Using in situ fish behaviour revealed by telemetry techniques as input, we developed an individual-based model (IBM) that simulated the Lagrangian trajectory of prey (fish) moving within a confined home range (HR). Fishers exhibiting various prototypical fishing styles targeted these fish in the model. We initially hypothesised that more active and more explorative individuals would be systematically removed under all fished conditions, in turn creating negative selection differentials on low activity phenotypes and maybe on small HR. Our results partly supported these general predictions. Standardised selection differentials were, on average, more negative on HR than on activity. However, in many simulation runs, positive selection pressures on HR were also identified, which resulted from the stochastic properties of the fishes’ movement and its interaction with the human predator. In contrast, there was a consistent negative selection on activity under all types of fishing styles. Therefore, in situations where catchability depends on spatial encounters between human predators and fish, we would predict a consistent selection towards low activity phenotypes and have less faith in the direction of the selection on HR size. Our study is the first theoretical investigation on the direction of fishery-induced selection of behaviour using passive fishing gears. The few empirical studies where catchability of fish was measured in relation to passive fishing techniques, such as gill-nets, traps or recreational fishing, support our predictions that fish in highly exploited situations are, on average, characterised by low swimming activity, stemming, in part, from negative selection on swimming activity.     

Temperature-dependent transmembrane potential changes in cells infected with a temperature-sensitive moloney sarcoma virus

Normal rat kidney cells (NRK) infected with the temperature-sensitive (ts) transformation mutant of Moloney murine sarcoma virus yielded a clone of cells, 6m2, that exhibited a transformed morphology at 33°C and a normal morphology at 39°C. Transmembrane potential (Em) was measured fluorometrically using a cyanine dye diS-C₃-(5). Fluorescence was inversely correlated with Em. Cells at 33°C had lower Em. Em changes were recorded within 15 minutes of temperature shift from 33°C to 39°C in both directions, increasing in the 33°C to 39°C direction and decreasing in the 39°C to 33°C direction. Uninfected NRK cells when shifted under the same condition exhibited small fluorescence changes in the 33°C to 39°C direction. Shifting from 39°C to 33°C resulted in Em changes similar to those in 6m2 cells. Also studied was a cell line infected with a spontaneous revertant of the ts mutant, designated 54-5A4; it was transformed at both temperatures. Shifting from 33°C to 39°C in both directions yielded small changes. Transmembrane potential changes in 6m2 cells precede other transformation-specific changes that occur after a temperature shift.