Kerncijfers biologische land- en tuinbouw

De biologische sector is volop in beweging. Veranderingen vinden zowel plaats aan de aanbodkant als aan de vraagkant. Nieuwe technieken, concentratie van ondernemingen, een toenemende consumentenvraag en supermarkten die het biologische product in hun assortiment opnemen zijn elementen die productie, distributie en afzet van biologische producten voor nieuwe uitdagingen stellen

Bioelectric-calcineurin signaling module regulates allometric growth and size of the zebrafish fin

AbstractThe establishment of relative size of organs and structures is paramount for attaining final form and function of an organism. Importantly, variation in the proportions of structures frequently underlies adaptive change in morphology in evolution and maybe a common mechanism underlying selection. However, the mechanism by which growth is integrated within tissues during development to achieve proper proportionality is poorly understood. We have shown that signaling by potassium channels mediates coordinated size regulation in zebrafish fins. Recently, calcineurin inhibitors were shown to elicit changes in zebrafish fin allometry as well. Here, we identify the potassium channelkcnk5bas a key player in integrating calcineurin’s growth effects, in part through regulation of the cytoplasmic C-terminus of the channel. We propose that the interaction between Kcnk5b and calcineurin acts as a signaling node to regulate allometric growth. Importantly, we find that this regulation is epistatic to inherent mechanisms instructing overall size as inhibition of calcineurin is able to bypass genetic instruction of size as seen insofand wild-type fins, however, it is not sufficient to re-specify positional memory of size of the fin. These findings integrate classic signaling mediators such as calcineurin with ion channel function in the regulation of size and proportion during growth.</jats:p

Growers say cannabis legalization excludes small growers, supports illicit markets, undermines local economies

H. Bodwitch is Postdoctoral Fellow, Department of Natural Resource Sciences, McGill University, Quebec, Canada; J. Carah is Senior Freshwater Ecologist, The Nature Conservancy, San Francisco; K.M. Daane is UC Cooperative Extension Specialist, Department of Environmental Science, Policy, and Management, UC Berkeley; C. Getz is Associate Cooperative Extension Specialist, Department of Environmental Science, Policy, and Management, UC Berkeley; T.E. Grantham is Assistant Cooperative Extension Specialist and Adjunct Professor, Department of Environmental Science, Policy, and Management, UC Berkeley; G.M. Hickey is Associate Professor, Department of Natural Resource Sciences, McGill University, Quebec, Canada; H. Wilson is Assistant Cooperative Extension Specialist, Department of Entomology, UC Riverside

Bioelectric Signaling Regulates Size in Zebrafish Fins

The scaling relationship between the size of an appendage or organ and that of the body as a whole is tightly regulated during animal development. If a structure grows at a different rate than the rest of the body, this process is termed allometric growth. The zebrafish another longfin (alf) mutant shows allometric growth resulting in proportionally enlarged fins and barbels. We took advantage of this mutant to study the regulation of size in vertebrates. Here, we show that alf mutants carry gain-of-function mutations in kcnk5b, a gene encoding a two-pore domain potassium (K+) channel. Electrophysiological analysis in Xenopus oocytes reveals that these mutations cause an increase in K+ conductance of the channel and lead to hyperpolarization of the cell. Further, somatic transgenesis experiments indicate that kcnk5b acts locally within the mesenchyme of fins and barbels to specify appendage size. Finally, we show that the channel requires the ability to conduct K+ ions to increase the size of these structures. Our results provide evidence for a role of bioelectric signaling through K+ channels in the regulation of allometric scaling and coordination of growth in the zebrafish

Writing Reality: Constructivism, Metaphor, and Cosmology

Two philosophies of metaphor are contrasted in constructing discourse and reality

Peripheral monitoring of direct and indirect alloantigen presentation pathways in clinical heart transplant recipients

It has been reported that the response to alloantigens presented by the direct and indirect pathway may be of differential relevance after human kidney transplantation. Accordingly, we monitored these routes in peripheral blood mononuclear cells (PBMC) of heart transplant patients from before transplantation and up to 2 years thereafter in an attempt to find a correlation with the clinical status of the patients. Both before and after transplantation, comparable proportions of PBMC samples reacted in mixed lymphocyte culture to nondepleted donor spleen cells (direct route), but never to donor cells depleted for antigen-presenting cells (indirect route). In contrast, the latter route could easily be activated by a nominal antigen and persisted after transplantation, although the proportion of PBMC samples responding was significantly suppressed, irrespective of the occurrence of rejection. Consequently, complete removal of antigen-presenting cells from the stimulator population in a mixed lymphocyte culture with PBMC as responder is not a suitable tool for measuring indirect presentation of alloantigens, and therefore not relevant for monitoring the immunological status of heart transplant recipients

A Study of Sodium Phenylsiliconate

The application of modern silicone chemistry knowledge and new analytical techniques to the elucidation of the structure of the hitherto uncharacterized, crystalline salt, sodium phenysiliconate, has been achieved. This salt, produced in 1914 by J. A. Meads and F. S. Kipping,. had been left structurally uncharacterized. This thesis builds upon the early work by applying to the problem the recent knowledge developed by J. F. Brown, Jr., and coworkers at the General Electric Research Laboratory. Derivatives of the salt were made and characterized by a variety of analytical techniques. The silanols produced by the acidification of the sodium phenylsiliconate are shown to yield the same derivatives as those made from cis-cis-cis-2,4,6,8-tetraphenycyclotetrasiloxane­tetrol. The nature of the sodium phenylsiliconate, as dictated by the experimental results, is discussed. The use of gel permeation chromatography has made it relatively easy to distinguish between the production of a monomeric or polymeric reaction product

Integrated agricultural research for development: lessons learnt and best practices

Changing the ways of doing business – business unusual – will require innovative approaches to building the required capacities in integrated Agricultural Research for Development. This paper outlines ICRA’s (International Centre for Development Oriented Research in Agriculture) continuing initiatives to develop, promote and nurture capacities in what ICRA has traditionally called Agricultural Research for Development (ARD) in response to changing demands and expectations placed upon agricultural and rural development professionals and institutions. The generic multi-stakeholder approach to rural innovation that integrates research into the broader development agenda of improved livelihoods, sustainable rural development and reduced poverty encompasses alternative research for development paradigms such as INRM and IAR4D, all aimed at improving the relevance, effectiveness and efficiency of agricultural research for development. The hands-on, pragmatic yet innovative approach to capacity development in ARD is outlined along with the Centre’s current efforts to expand South-South-North partnerships involving educational as well as research and development institutions in response to the increasing demand for capacity development in IAR4D. This is illustrated with an on-going collaborative initiative with NARO and Makerere University in Uganda and efforts to expand the approach to other countries of the region and to build up a sub-regional, network for capacity building in IAR4D, well placed to respond to the needs of such Africa-wide programs as the SSA-Challenge Program are discussed