The use of DNA fingerprinting to estimate annual survival rates in the Saker Falcon(Falco cherrug)

Summary DNA fingerprinting of nestlings ofFalco cherrug was used to determine indirectly the survival of the corresponding adult parent birds, which are difficult to catch in sufficient numbers. This approach is possible because Saker falcons show a high degree of site and mate tenacity. DNA profiles of nestlings from the same territory but from different years were compared. Three patterns of band-sharing coefficients between broods from the same territory were found: if band-sharing coefficients within and between broods from consecutive years were similar but significantly different from those of unrelated birds, it indicated that all young were full sibs and that neither adult was replaced between years. If band-sharing coefficients between broods at the same site indicated no relatedness across years and were equal to those of unrelated birds, then both breeding partners apparently had changed. If the band-sharing coefficients between broods of the same territory and consecutive years were significantly lower than those of full sibs, but higher than those of unrelated birds, the loss of one adult bird was indicated. The analysis of 32 broods (years 1993 to 1997) provided a minimal estimate for annual adult survival of 82% for a wild population of Saker Falcons in Kazakhstan.

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Abschätzung der jährlichen Überlebensraten des Sakerfalken(Falco cherrug) mittels DNA-Fingerprinting

Zusammenfassung Um die Gefährdung und Populationsdynamik des Sakerfalken (Falco cherrug) beurteilen zu können, benötigen wir genaue Angaben zu Mortalität und Überlebensraten. Während es bei dieser Art relativ einfach ist, Nestlinge zu fangen, ist es nahezu unmöglich, eine ausreichend große Zahl an Altvögeln zu markieren, um durch Wiederfang oder Ringfundmeldungen die jährliche Überlebensrate zu ermitteln. Durch DNA-Fingerprinting von Jungfalken haben wir versucht, die minimale Überlebensrate von Altfalken indirekt zu bestimmen. Dieser Forschungsansatz wird dadurch möglich, daß die Sakerfalken eine hohe Philopatrie aufweisen und jedes Jahr im selben Revier brüten. Wenn man mehrere Jahre lang Blutproben der Jungvögel aus denselben Revieren sammelt, so kann man mittels DNA Fingerprinting indirekt ermitteln, ob die jeweiligen Altvögel identisch waren oder gewechselt haben: Vergleicht man die Band-Sharing-Koeffizienten (BSK) von Jungvögeln von zwei oder mehr Jahren aus demselben Revier, so ergeben sich drei Muster: Wenn die BSK-Werte innerhalb der Bruten und zwischen den Bruten identisch aber signifikant verschieden von denen nicht verwandter Vögel sind, so handelt es sich bei den Jungvögeln um Vollgeschwister; demnach sind die Altvögel identisch geblieben, d. h. sie haben von einem Jahr zum nächsten überlebt. Wenn die BSK-Werte zwischen zwei Bruten aus demselben Revier einen Wert annehmen, wie man ihn für unverwandte Tiere ermittelt, so müssen die Eltern gewechselt haben. Liegen die Werte zwischen zwei Bruten signifikant höher als die von nicht verwandten Tieren, aber niedriger als diejenigen von Vollgeschwistern, so ist vermutlich 1 Altvogel gewechselt worden. Die Analyse von 32 Bruten des Sakerfalken aus Kasachstan zeigt, daß die minimale jährliche Adultüberlebensrate bei 82% liegt.

     

Multimodal nonlinear optical imaging of collagen arrays

We report multimodal nonlinear optical imaging of fascia, a rich collagen type I sheath around internal organs and muscle. We show that second harmonic generation (SHG), third harmonic generation (THG) and Coherent anti-Stokes Raman scattering (CARS) microscopy techniques provide complementary information about the sub-micron architecture of collagen arrays. Forward direction SHG microscopy reveals the fibrillar arrangement of collagen type I structures as the main matrix component of fascia. SHG images detected in the backward direction as well as images of forward direction CARS microscopy show that the longitudinal collagen fiber bundles are further arranged in sheet-like bands. Forward-THG microscopy reveals the optically homogeneous content of the collagen sheet on a spatial scale of the optical wavelength. This is supported by the fact that the third harmonic signal is observed only at the boundaries between the sheets as well as by the CARS data obtained in both directions. The observations made with THG and CARS microscopy are explained using atomic force microscopy images.     

Journeys through the Golgi—taking stock in a new era

The Golgi apparatus is essential for protein sorting and transport. Many researchers have long been fascinated with the form and function of this organelle. Yet, despite decades of scrutiny, the mechanisms by which proteins are transported across the Golgi remain controversial. At a recent meeting, many prominent Golgi researchers assembled to critically evaluate the core issues in the field. This report presents the outcome of their discussions and highlights the key open questions that will help guide the field into a new era.     

Immunity-related GTPase M (IRGM) proteins influence the localization of guanylate-binding protein 2 (GBP2) by modulating macroautophagy

The immunity-related GTPases (IRGs) are a family of proteins induced by interferon-γ that play a crucial role in innate resistance to intracellular pathogens. The M subfamily of IRG proteins (IRGM) plays a profound role in this context, in part because of the ability of its members to regulate the localization and expression of other IRG proteins. We present here evidence that IRGM proteins affect the localization of the guanylate-binding proteins (GBPs), a second family of interferon-induced GTP-binding proteins that also function in innate immunity. Absence of Irgm1 or Irgm3 led to accumulation of Gbp2 in intracellular compartments that were positive for both the macroautophagy (hereafter referred to as autophagy) marker LC3 and the autophagic adapter molecule p62/Sqstm1. Gbp2 was similarly relocalized in cells in which autophagy was impaired because of the absence of Atg5. Both in Atg5- and IRGM-deficient cells, the IRG protein Irga6 relocalized to the same compartments as Gbp2, raising the possibility of a common regulatory mechanism. However, other data indicated that Irga6, but not Gbp2, was ubiquitinated in IRGM-deficient cells. Similarly, coimmunoprecipitation studies indicated that although Irgm3 did interact directly with Irgb6, it did not interact with Gbp2. Collectively, these data suggest that IRGM proteins indirectly modulate the localization of GBPs through a distinct mechanism from that through which they regulate IRG protein localization. Further, these results suggest that a core function of IRGM proteins is to regulate autophagic flux, which influences the localization of GBPs and possibly other factors that instruct cell-autonomous immune resistance.     

MicroRNA miR-21 regulates the metastatic behavior of B16 melanoma cells

MicroRNA-21 (miR-21) is overexpressed in many human tumors and has been linked to various cellular processes altered in cancer. miR-21 is also up-regulated by a number of inflammatory agents, including IFN, which is of particular interest considering the close relationship between inflammation and cancer. Because miR-21 appears to be overexpressed in human melanoma, we examined the role of miR-21 in cancer development and metastasis in B16 mouse melanoma cells. We found that miR-21 is a member of an IFN-induced miRNA subset that requires STAT3 activation. To characterize the role of miR-21 in melanoma behavior, we transduced B16 cells with lentivirus encoding a miR-21 antagomir and isolated miR-21 knockdown B16 cells. miR-21 knockdown or IFN treatment alone inhibited B16 cell proliferation and migration in vitro, and in combination they had an enhanced effect. Moreover, miR-21 knockdown sensitized B16 cells to IFN-induced apoptosis. In B16 cells miR-21 targeted tumor suppressor (PTEN and PDCD4) and antiproliferative (BTG2) proteins. To characterize the role of miR-21 in vivo, empty vector- and antagomiR-21-transduced B16 melanoma cells were injected via tail vein into syngeneic C57BL/6 mice. Although empty vector-transduced B16 cells produced large lung metastases, miR-21 knockdown cells only formed small lung lesions. Importantly, miR-21 knockdown tumor-bearing mice exhibited prolonged survival compared with empty vector tumor-bearing mice. Thus, miR-21 regulates the metastatic behavior of B16 melanoma cells by promoting cell proliferation, survival, and migration/invasion as well as by suppressing IFN action, providing important new insights into the role of miR-21 in melanoma.     

An Interferon Response Gene Signature Is Associated with the Therapeutic Response of Hepatitis C Patients

Infection with the hepatitis C virus (HCV) is a major cause of chronic liver diseases and hepatocellular carcinoma worldwide, and thus represents a significant public health problem. The type I interferon (IFN), IFNα, has been successful in treating HCV-infected patients, but current IFN-based treatment regimens for HCV have suboptimal efficacy, and relatively little is known about why IFN therapy eliminates the virus in some patients but not in others. Therefore, it is critical to understand the basic mechanisms that underlie the therapeutic resistance to IFN action in HCV-infected individuals, and there is an urgent need to identify those patients most likely to respond to IFN therapy for HCV. To characterize the response of HCV-infected patients to treatment with IFNα, the expression of an IFN-response gene signature comprised of IFN-stimulated genes and genes that play an important role in the innate immune response was examined in liver biopsies from HCV-infected patients enrolled in a clinical trial. In the present study we found that the expression of a subset of IFN-response genes was dysregulated in liver biopsy samples from nonresponsive hepatitis C patients as compared with virologic responders. Based on these findings, a statistical model was developed to help predict the response of patients to IFN therapy, and compared to results obtained to the IL28 mutation model, which is highly predictive of the response to IFN-based therapy in HCV-infected patients. We found that a model incorporating gene expression data can improve predictions of IFN responsiveness compared to IL28 mutation status alone.