Predation research with electronic tagging

Predation is a fundamental aspect of ecology that drives ecosystem structure and function. A better understanding of predation can be facilitated by using electronic tags that log or transmit positions of predator or prey species in natural settings, however, there are special considerations that must be made to avoid biased estimates. We provide an overview of the tools available for studying predation with electronic tags including the tag types and analytical tools that can be used to identify where, when and how prey are killed by predators. We also discuss considerations for experimental design when studying predation using electronic tags, including how to minimize effects of capture and tagging procedures. Ongoing innovation and integration of sensors for tags will provide more detailed data about the performance of tagged predators and the fate of tagged prey. Where analysts can effectively resolve the timing of predation using state-of-the-art tags and analytical tools, we foresee exciting advances in our understanding of animal demographics, evolutionary trajectories and management systems. Prospects to develop new tools and approaches for tracking predation while designing studies to more effectively limit bias are an important frontier for understanding ecosystems and addressing human–wildlife conflicts. Given great uncertainties about environmen-tal change and intensifying conflicts between humans and predators, effective study designs integrating electronic tagging to study predation have a promising future in fundamental and applied ecologypublishedVersio

The effect of stromal integrin β3-deficiency on two different tumors in mice

There is an increasing focus on the tumor microenvironment in carcinogenesis. Integrins are important receptors and adhesion molecules in this environment and have been shown to be involved in cell adhesion, proliferation, differentiation and migration. The present study aimed to evaluate the effect of stromal integrin β3-deficiency on tumor growth, angiogenesis, interstitial fluid pressure (PIF), fibrosis and metastasis in a murine breast cancer (4T1) and a prostate tumor (RM11) model. We showed that stromal integrin β3-deficiency led to an elevation in PIF that correlated to a shift towards thicker collagen fibrils in the 4T1 mammary tumor. In the RM11 prostate carcinoma model there was no effect of integrin β3-deficiency on PIF and collagen fibril thickness. These findings support the notion that changes in the collagen scaffold influence PIF, and also indicate that there must be important crosstalk between the stroma and tumor cells, in a tumor cell line specific manner. Furthermore, stromal integrin β3-deficiency had no effect on tumor growth or angiogenesis in both tumor models and no effect on lung metastasis in the 4T1 mammary tumor model. In conclusion, the stromal β3 integrin influence PIF, possibly via its effect on the structure of the collagen network, in a tumor cell line dependent manner

Protein expression profiling of plasma and lungs at different stages of metastatic development in a human triple negative breast cancer xenograft model.

The main objective of this study was to identify single proteins or protein networks that might be used as diagnostic biomarkers or for therapeutic purposes by evaluating the protein expression profiling of plasma and lungs at different stages of metastatic development in a human triple negative MDA-MB-231 breast cancer xenograft model. MDA-MB-231 tumour cells were injected into the mammary fat pads on one side of the groin area. The mice were sacrificed day 19 (pre-metastases) and day 54 (metastases). Non-injected mice served as controls. Plasma was collected and lungs harvested for both immunohistochemistry and protein analysis. The most striking observation in plasma was the initial reduction in haptoglobin level at the pre-metastatic stage, to a following significant increase in haptoglobin level at the metastatic stage, with a more than 4000-fold increase from the pre-metastatic to the metastatic phase. A corresponding increase in haptoglobin level was also found in lung tissue after metastasis. Fibrinogen beta chain also had a similar change in expression level in plasma as haptoglobin, however not as prominent. There were also changes in plasma thrombospondin-4 and transferrin receptor protein 1 levels, from an increase at the pre-metastatic stage, to a significant fall when metastases were established. This suggests that especially changes in haptoglobin, but also fibrinogen beta chain, thrombospondin-4 and transferrin receptor protein 1 is indicative of metastasis, at least in this breast cancer model, and should be further evaluated as general breast cancer biomarkers

Stromal integrin α11β1 affects RM11 prostate and 4T1 breast xenograft tumors differently

Purpose It has been implied that the collagen binding integrin α11β1 plays a role in carcinogenesis. As still relatively little is known about how the stromal integrin α11β1 affects different aspects of tumor development, we wanted to examine the direct effects on primary tumor growth, fibrosis, tumor interstitial fluid pressure (PIF) and metastasis in murine 4T1 mammary and RM11 prostate tumors, using an in vivo SCID integrin α11-deficient mouse model. Methods Tumor growth was measured using a caliper, PIF by the wick-in-needle technique, activated fibroblasts by α-SMA immunofluorescence staining and fibrosis by transmission electron microscopy and picrosirius-red staining. Metastases were evaluated using hematoxylin and eosin stained sections. Results RM11 tumor growth was significantly reduced in the SCID integrin α11-deficient (α11-KO) compared to in SCID integrin α11 wild type (WT) mice, whereas there was no similar effect in the 4T1 tumor model. The 4T1 model demonstrated an alteration in collagen fibril diameter in the integrin α11-KO mice compared to WT, which was not found in the RM11 model. There were no significant differences in the amount of activated fibroblasts, total collagen content, collagen organization or PIF in the tumors in integrin α11-deficient mice compared to WT mice. There was also no difference in lung metastases between the two groups. Conclusion Deficiency of stromal integrin α11β1 showed different effects on tumor growth and collagen fibril diameter depending on tumor type, but no effect on tumor PIF or development of lung metastasis

Collagen fibrils were analyzed using transmission electron microscopy (TEM).

<p>Collagen fibril diameter distribution and average fibril diameter per tumor in 4T1 (n = 7 and n = 5) tumors (A, B), showed a shift towards thinner fibrils in SCID integrin α11-deficient (α11-KO) mice. RM11 tumors (n = 4 and n = 3) (C, D) and dermis (n = 4 and n = 3) (E, F) showed no significant differences in average collagen fibril diameter in SCID integrin α11 wild type (WT) and SCID integrin α11-deficient (α11-KO) mice (RM11 p = 0.20, dermis p = 0.47) using unpaired two-tailed t-test. Mean ± SD. * p < 0.006. Representative TEM images of collagen fibrils from both genotypes in 4T1 tumors (G, H), RM11 tumors (I, J) and dermis (K, L) are shown. Scale bars indicate 0.2 μm.</p

Digital fisheries data in the Internet age: Emerging tools for research and monitoring using online data in recreational fisheries

Recreational fisheries are diverse in scale, scope, and participation worldwide, constituting an important ecosystem service of marine and freshwater ecosystems. Management of these socio-ecological systems is challenged by monitoring gaps, stemming from difficulties engaging with participants, biased sampling, and insufficient resources to conduct biological or social surveys of fish and human populations. In the Internet age, online data have great potential to make a meaningful contribution to recreational fisheries research, monitoring, and management. Recreational fishers in some countries increasingly use social and other digital media to share their experiences with followers, with most data freely available to web scrapers that compile databases of text (e.g. tweets, status updates, comments), photos, videos and other media that contain information about spatiotemporal activity, sentiments towards catches/experiences, targeted and bycatch species, effort levels, and more. Although the future of recreational fisheries research, monitoring and management will likely involve more digital scraping, uptake is only just beginning and there are several challenges including tool availability/accessibility, sampling biases, and making findings relevant and usable to practitioners. Despite these challenges, we envision fisheries managers will increasingly turn towards online sources of fisheries data to supplement conventional methods. We challenge scientists to work towards continued method development and validation of various digital fisheries data tools and emphasize how biases from the online behaviour of users may complicate interpretations of these data for fisheries management.publishedVersio