Body length rather than routine metabolic rate and body condition correlates with activity and risk-taking in juvenile zebrafish Danio rerio.

In this study, the following hypotheses were explored using zebrafish Danio rerio: (1) individuals from the same cohort differ consistently in activity and risk-taking and (2) variation in activity and risk-taking is linked to individual differences in metabolic rate, body length and body condition. To examine these hypotheses, juvenile D. rerio were tested for routine metabolic rate and subsequently exposed to an open field test. Strong evidence was found for consistent among-individual differences in activity and risk-taking, which were overall negatively correlated with body length, i.e. larger D. rerio were found to be less active in a potentially dangerous open field and a similar trend was found with respect to a more direct measure of their risk-taking tendency. In contrast, routine metabolic rate and body condition were uncorrelated with both activity and risk-taking of juvenile D. rerio. These findings suggest that body length is associated with risk-related behaviours in juvenile D. rerio for which larger, rather than smaller, individuals may have a higher risk of predation, while the role for routine metabolic rate is relatively limited or non-existent, at least under the conditions of the present study.

Behaviour in a standardized assay, but not metabolic or growth rate, predicts behavioural variation in an adult aquatic top predator Esox lucius in the wild.

This study tested for links among behaviour, state and life-history variables as predicted by the pace-of-life hypothesis in adult pike Esox lucius. First, a standardized open-field behavioural assay was developed to assess individual behaviour of wild-captured adult E. lucius. Behaviour within the standardized assay predicted swimming behaviour in the lake, providing an ecological validation of the assay. There was no relationship between standardized behaviour and any of the life-history and state variables, including metabolism, body condition, juvenile growth rate and adult growth rate in contrast to predictions from the pace-of-life hypothesis. This study demonstrates that it is possible to assess ecologically relevant behavioural variation in a large-bodied top predator using a standard open-field assay, but it is noteworthy that this standardized behaviour is not systematically related to standard metabolism or growth.

Species-specific preferences of German recreational anglers for freshwater fishing experiences, with emphasis on the intrinsic utilities of fish stocking and wild fishes.

To answer the question, whether anglers have an intrinsic preference for stocking or a preference for catch outcomes (e.g. catch rates) believed to be maintained by stocking, a discrete choice experiment was conducted among a sample of anglers (n = 1335) in Lower Saxony, Germany. After controlling for catch aspects of the fishing experience, no significant influence of two stocking attributes (stocking frequency and composition of the catch in terms of wild v. hatchery fishes) on the utility gained from fishing was found for any of the freshwater species that were studied. It was concluded that the previously documented large appreciation of fish stocking by anglers may be indicative of an underlying preference for sufficiently high catches rather than reflect an intrinsic preference for stocking or the catching of wild fishes per se.

Experimental assessment of the probabilistic maturation reaction norm: condition matters.

The probabilistic maturation reaction norm (PMRN) describes an individual's probability of maturing at a given age as a function of size and other relevant phenotypic traits. Population-level shifts in the PMRN are often interpreted to indicate genetic as opposed to phenotypic changes in maturation in fish. Inferences derived from trends in the PMRN have been challenged, warranting an experimental assessment of the method. This was accomplished in a laboratory experiment using zebrafish (Danio rerio). Fish were reared under different food levels to induce variation in growth and maturation. Plasticity in maturation was not entirely captured by the demographic age- and length-based PMRN. Adding condition to the PMRN captured a greater amount of environmental variation in maturation probability. Nevertheless, significant differences in the PMRNs among the food levels remained after accounting for the influences of age, size and condition on maturation probability indicating plasticity of the PMRN. This was particularly pronounced between fish held on low food levels as compared with fish experiencing abundant resources, with the latter experiencing higher size-specific maturation probabilities. Our analysis emphasizes the need for incorporating salient physiological traits influencing maturation, such as condition, to make accurate inferences about documented shifts observed in the position of PMRNs on maturation trends in wild fish stocks.

Janus kinase 2 regulates Bcr-Abl signaling in chronic myeloid leukemia.

Despite the success of imatinib mesylate (IM) in the early chronic phase of chronic myeloid leukemia (CML), patients are resistant to IM and other kinase inhibitors in the later stages of CML. Our findings indicate that inhibition of Janus kinase 2 (Jak2) in Bcr-Abl+ cells overcomes IM resistance although the precise mechanism of Jak2 action is unknown. Knocking down Jak2 in Bcr-Abl+ cells reduced levels of the Bcr-Abl protein and also the phosphorylation of Tyr177 of Bcr-Abl, and Jak2 overexpression rescued these knockdown effects. Treatment of Bcr-Abl+ cells with Jak2 inhibitors for 4-6 h but not with IM also reduced Bcr-Abl protein and pTyr177 levels. In vitro kinase experiments performed with recombinant Jak2 showed that Jak2 readily phosphorylated Tyr177 of Bcr-Abl (a Jak2 consensus site, YvnV) whereas c-Abl did not. Importantly, Jak2 inhibition decreased pTyr177 Bcr-Abl in immune complexes but did not reduce levels of Bcr-Abl, suggesting that the reduction of Bcr-Abl by Jak2 inhibition is a separate event from phosphorylation of Tyr177. Jak2 inhibition by chemical inhibitors (TG101209/WP1193) and Jak2 knockdown diminished the activation of Ras, PI-3 kinase pathways and reduced levels of pTyrSTAT5. These findings suggest that Bcr-Abl stability and oncogenic signaling in CML cells are under the control of Jak2.

Size-dependent reproductive success of wild zebrafish Danio rerio in the laboratory.

Size-dependent reproductive success of wild zebrafish Danio rerio was studied under controlled conditions in the laboratory to further understand the influence of spawner body size on reproductive output and egg and larval traits. Three different spawner size categories attained by size-selective harvesting of the F(1)-offspring of wild D. rerio were established and their reproductive performance compared during a 5 day period. As to be expected, large females spawned more frequently and had significantly greater clutch sizes than small females. Contrary to expectations, small females produced larger eggs when measured as egg diameter with similar amounts of yolk compared to eggs spawned by large spawners. Eggs from small fish, however, suffered from higher egg mortality than the eggs of large individuals. Embryos from small-sized spawners also hatched later than offspring from eggs laid by large females. Larval standard length (L(S))-at-hatch did not differ between the size categories, but the offspring of the large fish had significantly larger area-at-hatch and greater yolk-sac volume indicating better condition. Offspring growth rates were generally similar between offspring from all size categories, but they were significantly higher for offspring spawned by small females in terms of L(S) between days 60 and 90 post-fertilization. Despite temporarily higher growth rates among the small fish offspring, the smaller energy reserves at hatching translated into lower condition later in ontogeny. It appeared that the influence of spawner body size on egg and larval traits was relatively pronounced early in development and seemed to remain in terms of condition, but not in growth, after the onset of exogenous feeding. Further studies are needed to explore the mechanisms behind the differences in offspring quality between large- and small-sized spawners by disentangling size-dependent maternal and paternal effects on reproductive variables in D. rerio.

Harmonizing recreational fisheries and conservation objectives for aquatic biodiversity in inland waters.

The importance of recreational fisheries to local and national economies, and as a generator of immense social welfare throughout the developed world, is well established. Development in the sector and its interaction with non-fishery-related nature conservation objectives for aquatic biodiversity, however, have the potential to generate conflict. This article reviews the intersection between recreational fisheries and nature conservation goals for aquatic biodiversity with specific reference to inland waters in industrialized countries, and the principal management activities and constraints that can lead to conflicts. A SWOT (strengths, weaknesses, opportunities and threats) analysis was used to review the issues facing sectoral development and identify options for future advancement of recreational fisheries to ameliorate potential conflicts with nature conservation goals. It is concluded that reconciliation of recreational fisheries and modern conservation perspectives is both possible and desirable, because many conservation problems also benefit fisheries quality. Angler buy-in to conservation is probable if (1) management scales are small, (2) threats to conservation originate from outside the fisheries sectors and (3) ecological awareness for the conservation problem is high. If these aspects are not present, reconciliation of recreational fisheries and nature conservation goals is less likely, risking both the aquatic biodiversity and the future of angling. To address these issues, enforcement of legislation and continued communication with angler communities is necessary, as well as development of integrated management policies that build on the instrumental values of aquatic biodiversity for recreational fisheries, while curtailing the more insidious threats to such biodiversity that originate directly from the recreational fisheries sector.

Jak2 inhibition deactivates Lyn kinase through the SET-PP2A-SHP1 pathway, causing apoptosis in drug-resistant cells from chronic myelogenous leukemia patients.

Chronic myelogenous leukemia (CML) patients treated with imatinib mesylate (IM) become drug resistant by mutations within the kinase domain of Bcr-Abl, and by other changes that cause progression to advanced stage (blast crisis) and increased expression of the Lyn tyrosine kinase, the regulation of which is not understood yet. In Bcr-Abl+ cells inhibition of Jak2, a downstream target of Bcr-Abl, by either Jak2 inhibitors or Jak2-specific short interfering RNA (siRNA) reduced the level of the SET protein, and increased PP2A Ser/Thr phosphatase and Shp1 tyrosine phosphatase activities, which led to decreased levels of activated Lyn. Activation of PP2A combined with Jak2 inhibition enhanced the reduction of activated Lyn kinase compared with Jak2 inhibition alone. In contrast, inhibition of either PP2A or Shp1 combined with Jak2 inhibition interfered with the loss of Lyn kinase activation more so than Jak2 inhibition alone, indicating the involvement of PP2A and Shp1 in the inactivation of the Lyn kinase caused by Jak2 inhibition. Inhibition of Jak2 induced apoptosis and reduced colony formation in IM-sensitive and -resistant Bcr-Abl mutant cell lines. Jak2 inhibition also induced apoptosis in CML cells from blast crisis patients but not in normal hematopoietic cells. These results indicate that Lyn is downstream of Jak2, and Jak2 maintains activated Lyn kinase in CML through the SET-PP2A-Shp1 pathway.

Contrasting pragmatic and suffering-centred approaches to fish welfare in recreational angling.

Two views dealing with fish welfare in recreational fishing are discussed in an effort to stimulate the current discourse on the topic. The pragmatic approach asks whether and how strongly recreational fishing compromises the health and fitness of individual fishes and what can be done to avoid or mitigate such effects. Its implementation rests on accepting recreational fishing as a principally legitimate activity. The second approach to fish welfare focuses on suffering and pain in fishes and is usually morally prescriptive. Its central tenet is that some or all recreational fishing practices may be unacceptable unless sufficient benefits to humans are created, which justify the supposedly cruel treatment of the fishes. The pragmatic approach to fish welfare is preferred because it relies on objectively measurable variables of impaired fish welfare (e.g. physiological, behavioural or fitness indicators) and does not question recreational fishing on moral grounds. Contrary to a suffering-centred approach to fish welfare, a pragmatic perspective emphasizes positive messages and facilitates constructive dialogue among stakeholders. In contrast, a suffering-centred approach to fish welfare tends to promote tension and enduring conflict that cannot be reconciled objectively and thus should be avoided.

Lipocalin 2 is required for BCR-ABL-induced tumorigenesis.

Our previous studies indicate that reduction of lipocalin 2 (mouse 24p3) expression by either anti-sense or siRNA approaches strongly reduces the overgrowth of BCR-ABL+ mouse myeloid 32D in marrow and spleen of NOD/SCID mice. In this study, we used the mouse bone marrow transplant model to further explore the role of 24p3 in BCR-ABL-induced leukemia. Consistent with our previous findings, when using non-irradiated mice as recipient, donor marrow cells expressing BCR-ABL but lacking 24p3 did not cause leukemia or any disease after 75 days, whereas all mice receiving wild type BCR-ABL donor cells died with CML-like disease. An agar clone of the BCR-ABL+ human CML cell line K562 (C5) that secretes relatively high levels of lipocalin 2 (human NGAL) induced suppression of hematopoiesis in spleen and marrow of mice, leading to early death in contrast to parental K562 or K562 clone (C6) expressing low amounts of NGAL. Compared with K562 cells, overexpressing NGAL in K562 led to a higher apoptosis rate and an atrophy phenotype in the spleen of the inoculated mice. Plasma from both leukemic mice and CML patients showed elevated lipocalin 2 levels compared with healthy individuals. Moreover, we found that a primary stable cell line from wild-type mouse marrow cells expressing BCR-ABL caused solid tumors in nude mice whereas a similar BCR-ABL+ cell line from 24p3 null mice did not. These findings demonstrate that lipocalin 2 has at least two functions related to tumorigenesis, one involving apoptosis induction of normal hematopoietic cells and the other being tissue invasion by leukemia cells.

Engaging recreational fishers in management and conservation: global case studies.

Globally, the number of recreational fishers is sizeable and increasing in many countries. Associated with this trend is the potential for negative impacts on fish stocks through exploitation or management measures such as stocking and introduction of non-native fishes. Nevertheless, recreational fishers can be instrumental in successful fisheries conservation through active involvement in, or initiation of, conservation projects to reduce both direct and external stressors contributing to fishery declines. Understanding fishers' concerns for sustained access to the resource and developing methods for their meaningful participation can have positive impacts on conservation efforts. We examined a suite of case studies that demonstrate successful involvement of recreational fishers in conservation and management activities that span developed and developing countries, temperate and tropical regions, marine and freshwater systems, and open- and closed-access fisheries. To illustrate potential benefits and challenges of involving recreational fishers in fisheries management and conservation, we examined the socioeconomic and ecological contexts of each case study. We devised a conceptual framework for the engagement of recreational fishers that targets particular types of involvement (enforcement, advocacy, conservation, management design [type and location], research, and monitoring) on the basis of degree of stakeholder stewardship, scale of the fishery, and source of impacts (internal or external). These activities can be enhanced by incorporating local knowledge and traditions, taking advantage of leadership and regional networks, and creating collaborations among various stakeholder groups, scientists, and agencies to maximize the probability of recreational fisher involvement and project success.

Effective killing of Gleevec-resistant CML cells with T315I mutation by a natural compound PEITC through redox-mediated mechanism.

Mutation of Bcr-Abl is an important mechanism by which chronic myelogenous leukemia (CML) cells become resistant to Gleevec. The T315I mutation is clinically significant since CML cells harboring this mutation are insensitive to Gleevec and other Bcr-Abl-targeted drugs. Identification of new agents capable of effectively killing CML cells with T315I mutation would have important therapeutic implications in Gleevec-resistant CML. Here, we showed that beta-phenylethyl isothiocyanate (PEITC), a natural compound found in vegetables, is effective in killing CML cells expressing T315I BCR-ABL. Treatment of leukemia cell lines harboring wild-type or mutant Bcr-Abl with 10 microM PEITC resulted in an elevated ROS stress and a redox-mediated degradation of the BCR-ABL protein, leading to massive death of the leukemia cells. Antioxidant NAC attenuated the PEITC-induced oxidative stress in CML cells and prevented the degradation of BCR-ABL, caspase-3 activation and cell death. We further showed that the ROS-induced degradation of BCR-ABL was mediated partially by caspase-3 and the proteasome pathway. The ability of PEITC to effectively kill T315I-positive CML cells was further confirmed using primary leukemia cells isolated from CML patients. Our results suggest that PEITC is a promising compound capable of killing Gleevec-resistant CML cells through a ROS-mediated mechanism and warrants further investigations.

Activated c-Abl tyrosine kinase in malignant solid tumors.

Mutant forms of the c-ABL gene are well known to be involved in hematopoietic malignancies such as chronic myeloid leukemia (CML). CML patients possess a fused BCR-ABL gene that activates the Abl tyrosine kinase domain within Bcr-Abl. In general fusion proteins that cause oligomerization of Abl lead to activation of its tyrosine kinase activity. In this review, we highlight recent discoveries indicating that the activated c-Abl tyrosine kinase, not as a fusion protein, plays an important role in malignant solid tumors of lung and breast.

BCR-ABL oncogenic transformation of NIH 3T3 fibroblasts requires the IL-3 receptor.

Oncogenic transformation of hematopoietic cells by the Bcr-Abl oncoprotein directly involves the activation Jak2 tyrosine kinase and the Stat5 transcription factor. Both proteins are normally linked to the interleukin (IL)-3/granulocyte-macrophage colony-stimulating factor receptors for growth and survival. Since fibroblastic cells are not targets of BCR-ABL-induced oncogenesis, we determined whether forced expression of the IL-3 receptor would allow oncogenic transformation of NIH 3T3 fibroblasts known to be resistant to transformation by BCR-ABL. NIH 3T3 cells transduced with the human IL-3 receptor alpha and beta chains were highly susceptible to oncogenic transformation by expression of BCR-ABL. Forced expression of both receptor chains but not either one alone allowed efficient foci formation of NIH 3T3 cells expressing BCR-ABL (triple positive cells), and these cells formed colonies in soft agar, whereas BCR-ABL+ NIH 3T3 cells lacking IL-3 receptor expression did not. Signaling studies indicate that the BCR-ABL/IL-3 receptor+ NIH 3T3 cells utilize the Gab2/PI-3 kinase pathway activated by Jak2, and the Stat5 pathway activated separately by Bcr-Abl, whereas BCR-ABL+ NIH 3T3 cells lacking the IL-3 receptor do not utilize the Jak2 pathway, but still maintain activation of Stat5. The Bcr-Abl kinase inhibitor imatinib mesylate (1 microM) and two Jak2 kinase inhibitors strongly inhibited agar colony formation and the activation of Gab2 caused by Jak2. All of these findings indicate that Bcr-Abl oncoprotein requires the IL-3 receptor/Jak2/Stat5 pathways for oncogenic transformation of NIH 3T3 fibroblasts.

Kinase domain mutants of Bcr enhance Bcr-Abl oncogenic effects.

Bcr-Abl acquires its transforming ability through its upregulated Abl tyrosine kinase activity. Bcr is a phosphoprotein with a novel serine/threonine kinase activity encoded by its first exon. In chronic myelogenous leukemia (CML) cells, Bcr-Abl phosphorylates Bcr on tyrosine residues reducing its kinase activity. Overexpression of BCR in BCR-ABL+ cells produces a phosphoserine form of Bcr, which inhibits the oncogenic effects of BCR-ABL. To investigate the inhibitory effects of Bcr on Bcr-Abl, we expressed BCR/GFP in TonB210 cells, which contain a tetracycline-inducible BCR-ABL. In nude mice injected with cell clones of TonB210/BCR/GFP, tumor formation was delayed, and tumors were 50% smaller compared with the TonB210/GFP. In addition, TonB210/ BCR/GFP cells had little colony-forming ability in soft agar compared with TonB210/GFP cells. In contrast, a point mutant of BCR (Y360F), which disrupts its kinase activity, not only blocked Bcr's inhibitory effects but also enhanced the oncogenic effects of Bcr-Abl in a solid tumor model and in soft agar colony assays. Similar effects were observed with a second BCR kinase domain mutant, S354A. These results indicate that the inhibitory function of Bcr directed toward Bcr-Abl requires its kinase function.

Characterization of a reference material for BCR-ABL (M-BCR) mRNA quantitation by real-time amplification assays: towards new standards for gene expression measurements.

Monitoring of BCR-ABL transcripts has become established practice in the management of chronic myeloid leukemia. However, nucleic acid amplification techniques are prone to variations which limit the reliability of real-time quantitative PCR (RQ-PCR) for clinical decision making, highlighting the need for standardization of assays and reporting of minimal residual disease (MRD) data. We evaluated a lyophilized preparation of a leukemic cell line (K562) as a potential quality control reagent. This was found to be relatively stable, yielding comparable respective levels of ABL, GUS and BCR-ABL transcripts as determined by RQ-PCR before and after accelerated degradation experiments as well as following 5 years storage at -20 degrees C. Vials of freeze-dried cells were sent at ambient temperature to 22 laboratories on four continents, with RQ-PCR analyses detecting BCR-ABL transcripts at levels comparable to those observed in primary patient samples. Our results suggest that freeze-dried cells can be used as quality control reagents with a range of analytical instrumentations and could enable the development of urgently needed international standards simulating clinically relevant levels of MRD.