Internationalization and Corporate Success - Empirical Evidence from the European Dairy Sector

Increasingly, cooperatives in the agribusiness are being confronted with the globalization of agri-food markets. Cooperatives adapt to this development by internationalizing their activities. This paper presents a method of measuring the degree of internationalization (DoI) and its application to European cooperatives in the dairy sector. Then, the financial performance of these cooperatives is measured by applying balance sheet analysis. The paper ends with a discussion of why German cooperatives are noticeably less internationalized and show weaker financial performance than their European competitors.globalization, dairy industry, cooperatives, degree of internationalization, corporate success, Agribusiness, Livestock Production/Industries,

Transport by molecular motors in the presence of static defects

The transport by molecular motors along cytoskeletal filaments is studied theoretically in the presence of static defects. The movements of single motors are described as biased random walks along the filament as well as binding to and unbinding from the filament. Three basic types of defects are distinguished, which differ from normal filament sites only in one of the motors' transition probabilities. Both stepping defects with a reduced probability for forward steps and unbinding defects with an increased probability for motor unbinding strongly reduce the velocities and the run lengths of the motors with increasing defect density. For transport by single motors, binding defects with a reduced probability for motor binding have a relatively small effect on the transport properties. For cargo transport by motors teams, binding defects also change the effective unbinding rate of the cargo particles and are expected to have a stronger effect.Comment: 20 pages, latex, 7 figures, 1 tabl

Physics of Transport and Traffic Phenomena in Biology: from molecular motors and cells to organisms

Traffic-like collective movements are observed at almost all levels of biological systems. Molecular motor proteins like, for example, kinesin and dynein, which are the vehicles of almost all intra-cellular transport in eukayotic cells, sometimes encounter traffic jam that manifests as a disease of the organism. Similarly, traffic jam of collagenase MMP-1, which moves on the collagen fibrils of the extracellular matrix of vertebrates, has also been observed in recent experiments. Traffic-like movements of social insects like ants and termites on trails are, perhaps, more familiar in our everyday life. Experimental, theoretical and computational investigations in the last few years have led to a deeper understanding of the generic or common physical principles involved in these phenomena. In particular, some of the methods of non-equilibrium statistical mechanics, pioneered almost a hundred years ago by Einstein, Langevin and others, turned out to be powerful theoretical tools for quantitaive analysis of models of these traffic-like collective phenomena as these systems are intrinsically far from equilibrium. In this review we critically examine the current status of our understanding, expose the limitations of the existing methods, mention open challenging questions and speculate on the possible future directions of research in this interdisciplinary area where physics meets not only chemistry and biology but also (nano-)technology.Comment: 33 page Review article, REVTEX text, 29 EPS and PS figure

Tumor Necrosis Factor Induces Hyperphosphorylation of Kinesin Light Chain and Inhibits Kinesin-Mediated Transport of Mitochondria

The molecular motor kinesin is an ATPase that mediates plus end-directed transport of organelles along microtubules. Although the biochemical properties of kinesin are extensively studied, conclusive data on regulation of kinesin-mediated transport are largely lacking. Previously, we showed that the proinflammatory cytokine tumor necrosis factor induces perinuclear clustering of mitochondria. Here, we show that tumor necrosis factor impairs kinesin motor activity and hyperphosphorylates kinesin light chain through activation of two putative kinesin light chain kinases. Inactivation of kinesin, hyperphosphorylation of kinesin light chain, and perinuclear clustering of mitochondria exhibit the same p38 mitogen-activated kinase dependence, indicating their functional relationship. These data provide evidence for direct regulation of kinesin-mediated organelle transport by extracellular stimuli via cytokine receptor signaling pathways

MAPping out distribution routes for kinesin couriers

In the crowded environment of eukaryotic cells, diffusion is an inefficient distribution mechanism for cellular components. Long-distance active transport is required and is performed by molecular motors including kinesins. Furthermore, in highly polarized, compartmentalized and plastic cells such as neurons, regulatory mechanisms are required to ensure appropriate spatio-temporal delivery of neuronal components. The kinesin machinery has diversified into a large number of kinesin motor proteins as well as adaptor proteins that are associated with subsets of cargo. However, many mechanisms contribute to the correct delivery of these cargos to their target domains. One mechanism is through motor recognition of subdomain-specific microtubule (MT) tracks, sign-posted by different tubulin isoforms, tubulin post-translational modifications (PTMs), tubulin GTPase activity and MT associated proteins (MAPs). With neurons as a model system, a critical review of these regulatory mechanisms is presented here, with particular focus on the emerging contribution of compartmentalised MAPs. Overall, we conclude that – especially for axonal cargo – alterations to the MT track can influence transport, although in vivo, it is likely that multiple track-based effects act synergistically to ensure accurate cargo distribution

The amino terminus of tau inhibits kinesin-dependent axonal transport: Implications for filament toxicity

Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Journal of Neuroscience Research 87 (2009): 440-451, doi:10.1002/jnr.21850.The neuropathology of Alzheimer’s disease (AD) and other tauopathies is characterized by filamentous deposits of the microtubule-associated protein tau, but the relationship between tau polymerization and neurotoxicity is unknown. Here, we examined effects of filamentous tau on fast axonal transport (FAT) using isolated squid axoplasm. Monomeric and filamentous forms of recombinant human tau were perfused in axoplasm, and their effects on kinesin- and dyneindependent FAT rates evaluated by video microscopy. While perfusion of monomeric tau at physiological concentrations showed no effect, tau filaments at the same concentrations selectively inhibited anterograde (kinesin-dependent) FAT, triggering the release of conventional kinesin from axoplasmic vesicles. Pharmacological experiments indicated that the effect of tau filaments on FAT is mediated by protein phosphatase 1 (PP1) and glycogen synthase kinase-3 (GSK-3) activities. Moreover, deletion analysis suggested that these effects depend on a conserved 18-amino acid sequence at the amino terminus of tau. Interestingly, monomeric tau isoforms lacking the C-terminal half of the molecule (including the microtubule binding region) recapitulated the effects of full-length filamentous tau. Our results suggest that pathological tau aggregation contributes to neurodegeneration by altering a regulatory pathway for FAT.Research supported by NIH awards NS049834 (N.E.L.), AG14453 (L.I.B.), NINDS grants NS23868, NS23320, NS41170 and NS43408 (S.B.), MDA (S.B.), ALSA (G.M, S.B), and HDSA (G.M.)

HUMMR, a hypoxia- and HIF-1α–inducible protein, alters mitochondrial distribution and transport

Mitochondrial transport is critical for maintenance of normal neuronal function. Here, we identify a novel mitochondria protein, hypoxia up-regulated mitochondrial movement regulator (HUMMR), which is expressed in neurons and is markedly induced by hypoxia-inducible factor 1 α (HIF-1α). Interestingly, HUMMR interacts with Miro-1 and Miro-2, mitochondrial proteins that are critical for mediating mitochondrial transport. Interestingly, knockdown of HUMMR or HIF-1 function in neurons exposed to hypoxia markedly reduces mitochondrial content in axons. Because mitochondrial transport and distribution are inextricably linked, the impact of reduced HUMMR function on the direction of mitochondrial transport was also explored. Loss of HUMMR function in hypoxia diminished the percentage of motile mitochondria moving in the anterograde direction and enhanced the percentage moving in the retrograde direction. Thus, HUMMR, a novel mitochondrial protein induced by HIF-1 and hypoxia, biases mitochondria transport in the anterograde direction. These findings have broad implications for maintenance of neuronal viability and function during physiological and pathological states