The synaptic Muscle-Specific Kinase (MuSK) complex: new partners, new functions.

The muscle-specific kinase MuSK is part of an agrin receptor complex which stimulates tyrosine phosphorylation and drives clustering of acetylcholine receptors (AChRs) in the postsynaptic membrane at the vertebrate neuromuscular junction. MuSK also regulates synaptic gene transcription in subsynaptic nuclei. Over the past few years decisive progress has been made in the identification of MuSK effectors, helping at understanding its function in the formation of the NMJ. Alike AChR, MuSK and several of its partners are the target of mutations responsible for diseases of the NMJ, such as congenital myasthenic syndromes. This minireview will focus on the multiple MuSK effectors so far identified that place MuSK at the center of a multifunctional signaling complex involved in the organization of the NMJ and associated disorders

Evidence for in situ and in vitro association between beta-dystroglycan and the subsynaptic 43K rapsyn protein. Consequence for acetylcholine receptor clustering at the synapse.

The accumulation of dystrophin and associated proteins at the postsynaptic membrane of the neuromuscular junction and their co-distribution with nicotinic acetylcholine receptor (AChR) clusters in vitro suggested a role for the dystrophin complex in synaptogenesis. Co-transfection experiments in which alpha- and beta-dystroglycan form a complex with AChR and rapsyn, a peripheral protein required for AChR clustering (Apel, D. A., Roberds, S. L., Campbell, K. P., and Merlie, J. P. (1995) Neuron 15, 115-126), suggested that rapsyn functions as a link between AChR and the dystrophin complex. We have investigated the interaction between rapsyn and beta-dystroglycan in Torpedo AChR-rich membranes using in situ and in vitro approaches. Cross-linking experiments were carried out to study the topography of postsynaptic membrane polypeptides. A cross-linked product of 90 kDa was labeled by antibodies to rapsyn and beta-dystroglycan; this demonstrates that these polypeptides are in close proximity to one another. Affinity chromatography experiments and ligand blot assays using rapsyn solubilized from Torpedo AChR-rich membranes and constructs containing beta-dystroglycan C-terminal fragments show that a rapsyn-binding site is present in the juxtamembranous region of the cytoplasmic tail of beta-dystroglycan. These data point out that rapsyn and dystroglycan interact in the postsynaptic membrane and thus reinforce the notion that dystroglycan could be involved in synaptogenesis

MuSK is required for anchoring acetylcholinesterase at the neuromuscular junction

At the neuromuscular junction, acetylcholinesterase (AChE) is mainly present as asymmetric forms in which tetramers of catalytic subunits are associated to a specific collagen, collagen Q (ColQ). The accumulation of the enzyme in the synaptic basal lamina strictly relies on ColQ. This has been shown to be mediated by interaction between ColQ and perlecan, which itself binds dystroglycan. Here, using transfected mutants of ColQ in a ColQ-deficient muscle cell line or COS-7 cells, we report that ColQ clusterizes through a more complex mechanism. This process requires two heparin-binding sites contained in the collagen domain as well as the COOH terminus of ColQ. Cross-linking and immunoprecipitation experiments in Torpedo postsynaptic membranes together with transfection experiments with muscle-specific kinase (MuSK) constructs in MuSK-deficient myotubes or COS-7 cells provide the first evidence that ColQ binds MuSK. Together, our data suggest that a ternary complex containing ColQ, perlecan, and MuSK is required for AChE clustering and support the notion that MuSK dictates AChE synaptic localization at the neuromuscular junction

Epidemiological study concerning the characteristics of organic pig farming in selected European countries

Interviews and on-farm assessments were conducted in a total of 101 organic pig farms in different European countries (Austria, Denmark, France, Germany, Italy, and Sweden) to gain knowledge about farm management and health status of organic pigs in Europe. 66 farms kept at least one age group outdoors while 35 farms kept their pigs exclusively indoors, for the most part with a concrete outside run. Housing and feeding conditions were characterised by a large heterogeneity within and between European countries. On many farms, the feeding regimes seemed suboptimal, leaving ample room for easily feasible improvements. With respect to the health management, some farms made comprehensive use of the various options, whereas many farmers neglected the implementation of preventive measures, including appropriate hygiene and disinfection measures. On the majority of organic farms with indoor housing, the options for disinfection were hindered by the fact that many farms were not able to implement an all-in all-out concept. In correspondence with the large variation in the living conditions for pigs, also production data and mortality rates differed widely between organic pig farms. According to the estimation by the farmer concerning the occurrence of selected animal health problems, mortality of suckling piglets and weaners and weaning diarrhoea were named as the most relevant disease problems. Although dedicated to the same minimum standards, it can be concluded that organic pig farming does not provide the same living conditions or a homogenous outcome of animal health parameters but, like all systems, also depends on the quality of management. Differences in management practices, housing conditions, restrictions in the availability of resources (labour time, financial budget etc.), and a lack of feedback and control mechanism within the farm system appears to be a main reason for the substantial variation between farms

Treating clinical mastitis in dairy cows with essential oils

Clinical mastitis is the main concern in dairy farming today, but there are very few drugs that are compatible with organic specifications. Our study was conducted in order to evaluate the therapeutic efficiency of the intramammary infusion of three essential oils, Thymus vulgaris, Rosmarinus verbenone and Laurus nobilis. Fifty-five cases of mastitis were treated with 10 ml of a mixture of the three oils (1.5% each in sunflower oil). Forty-five others were treated with 10 ml of a mixture of Thymus vulgaris and Rosmarinus verbenone (6% of each in sunflower oil or in water). The recovery rate was only 40%, which is deemed unsatisfactory

Intercalibration of a concentration McMaster Technique between eight European laboratories

Prior to a European prevalence survey of intestinal parasites of organic pig herds it was decided to introduce one common technique for faecal egg counts and to compare its execution at all involved laboratories to ensure data compatibility. It was clearly shown that avoid confounding variation it is extremely important not only to use identical techniques but also to implement the technique in exactly the same way

Health status in organic pig herds in Europe

Introduction Organic pig production is still a small-scale produc-tion, achieving, however, increased interest by con-sumers who are concerned about the conventional production method. The EU-Regulation (EEC-No. 1804/1999) on organic livestock production, now replaced by EEC-No 834/2007, was introduced to provide a framework ensuring living conditions for organic livestock to be better than those in conven-tional systems and to harmonize the rules across member states. Scientifically based information on how and to what degree the EU-Regulation contrib¬utes to the objective of a high status of pig health in organic farming is scarce. Further information is needed to assess whether consumer expectations in organic pig production in Europe are met. MATERIAL AND METHODS An epidemiological study was performed on 101 organic sow herds in 6 European countries (Denmark, Germany, Austria, Sweden, Italy and France). 13 to 20 farms per country were assessed. On-farm data included a comprehensive interview with the herd manager in relation to housing conditions, feeding regime, data acquisition, cleaning and disinfection measures, medicine usage, culling reasons, vaccina¬tion protocols, etc.. Recorded livestock data included: liveborn and stillborn piglets/farrowing, weaned piglets/sow/year, piglet losses/farrowing, losses of weaned piglets, litters /sow lifetime, and the preva-lence of diseases according to the treatment records. Data from all countries were merged into one joint database and analysed statistically. Results Although dedicated to the same minimum standards, the farm structures were characterised by a huge heterogeneity. 67 farms were keeping their sows outdoors while 34 farms were indoors with outside runs. Group suckling was implemented on 52% of the farms. The degree of specialisation was compara¬tively low. About 40% of the farms had another eco¬nomically relevant livestock enterprise on the farm apart from keeping pigs. Farmers differed widely in their feeding regimes, in making use of phase feeding and diet calculations. Moreover, the farms varied in the cleaning management and in the implementation of disinfection measures. The study also revealed large differences in animal health management with respect to the use of quarantine, availability of hospi¬tal pens, presence of the farmer during farrowing, and regarding routine measures such as castration, teeth reduction, and iron supplementation of piglets. For 50 % of the farms the abattoirs provided feedback of pathological findings for slaughtered sows, and 80 % for fattening pigs. Huge differ-ences were detected in the perception of the farmers with regard to health problems on their farm and with respect to the availability of labo-ratory results. Mean mortality rates of piglets until and after weaning averaged 19.7 ± 9.7% and 4.9 ± 5.4% resp., showing clear differences between coun¬tries and farms. Mean values for the annual re¬placement rates of sows and litters per sow life-time were 32.4 ± 14.3% and 6.3 ± 2.3 resp. Ac-cording to the treatment records, metritis and mastitis appeared as the predominant diseases of the sows, nearly all treated with antibiotics, fol-lowed by cases of lameness and abscesses. In the case of suckling piglets, diarrhoea, arthritis and respiratory diseases were predominant. Also the weaned piglets suffered primarily from diarrhoea. Farms showed an incidence of 27.6 ± 34.3%. of piglets treated with antibiotics against diarrhoea. Conclusions The results indicated that in general the status of animal health in organic pig herds was compara¬ble to data found on conventional farms. Differ¬ences between farms appear to be greater than those between production methods. Obviously, the production method defined by standards does not provide a homogenous outcome with respect to the animal health status. Differences in man¬agement practices and in feedback and control mechanisms within the farm system might be the main reasons for substantial variation in the prevalence rates of diseases. Any improvements in organic pig production require the use of feed¬back mechanisms and a clear definition of the expected results with respect to the outcome of the farm system. Consequently, there is a need for a change in the paradigm from standard and resource oriented to a result and outcome ori¬ented approach. The implementation of a moni¬toring system including on farm clinical assess¬ment, abattoir data and review of treatment data, concepts to deal with potential problems (e.g. health planning strategies, HACCP protocols, etc.) and a definition of the expected results with respect to the output of the farm system might be a way forward for organic farming ensuring a high status of animal health and welfare