Cleavage of IgG1 and IgG3 by gingipain K from Porphyromonas gingivalis may compromise host defense in progressive periodontitis

Degradation of immunoglobulins is an effective strategy of bacteria to evade the immune system. We have tested whether human IgG is a substrate for gingipain K of Porphyromonas gingivalis and found that the enzyme can hydrolyze subclass 1 and 3 of human IgG. The heavy chain of IgG(1) was cleaved at a single site within the hinge region, generating Fab and Fc fragments. IgG(3) was also cleaved within the heavy chain, but at several sites around the CH2 region. Investigation of the enzyme kinetics of IgG proteolysis by gingipain K, using FPLC- and isothermal titration calorimetry-based assays followed by Hill plots, revealed non-Michaelis-Menten kinetics involving a mechanism of positive cooperativity. In ex vivo studies, it was shown that gingipain K retained its IgG hydrolyzing activity in human plasma despite the high content of natural protease inhibitors; that IgG(1) cleavage products were detected in gingival crevicular fluid samples from patients with severe periodontitis; and that gingipain K treatment of serum samples from patients with high antibody titers against P. gingivalis significantly hindered opsonin-dependent phagocytosis of clinical isolates of P. gingivalis by neutrophils. Altogether, these findings underline a biological function of gingipain K as an IgG protease of pathophysiological importance.

Soil conservation in Swiss agriculture - Approaching abstract and symbolic meanings in farmers' life-worlds

This paper explores the significance of ‘life-worlds’ for better understanding why farmers adopt or reject soil conservation measures and for identifying basic dimensions to be covered by social learning processes in Swiss agricultural soil protection. The study showed that farmers interpret soil erosion and soil conservation measures against the background of their entire life-world. By doing so, farmers consider abstract and symbolic meanings of soil conservation. This is, soil conservation measures have to be feasible and practical in the everyday farming routine, however, they also have to correspond with their aesthetic perception, their value system and their personal and professional identities. Consequently, by switching to soil conservation measures such as no-tillage farmers have to adapt not only the routines of their daily farming life, but also their perception of the aesthetics of cultivated land, underlying values and images of themselves. Major differences between farmers who adopt and farmers who reject no-tillage were found to depend on the degree of coherence they could create between the abstract and symbolic meanings of the soil conservation measure. From this perspective, implementation of soil protection measures faces the challenge of facilitating interactions between farmers, experts and scientists at a ‘deeper’ level, with an awareness of all significant dimensions that characterise the life-world. The paper argues that a certain level of shared symbolic meaning is essential to achieving mutual understanding in social learning processes.

Reshaping Rural Extension: Learning for Sustainability (LforS): An Integrative and Learning-Based Advisory Approach for Rural Extension with Small-Scale Farmers

This publication offers concrete suggestions for implementing an integrative and learning-oriented approach to agricultural extension with the goal of fostering sustainable development. It targets governmental and non-governmental organisations, development agencies, and extension staff working in the field of rural development. The book looks into the conditions and trends that influence extension today, and outlines new challenges and necessary adaptations. It offers a basic reflection on the goals, the criteria for success and the form of a state-of-the-art approach to extension. The core of the book consists of a presentation of Learning for Sustainability (LforS), an example of an integrative, learning-oriented approach that is based on three crucial elements: stakeholder dialogue, knowledge management, and organizational development. Awareness raising and capacity building, social mobilization, and monitoring & evaluation are additional building blocks. The structure and organisation of the LforS approach as well as a selection of appropriate methods and tools are presented. The authors also address key aspects of developing and managing a learning-oriented extension approach. The book illustrates how LforS can be implemented by presenting two case studies, one from Madagascar and one from Mongolia. It addresses conceptual questions and at the same time it is practice-oriented. In contrast to other extension approaches, LforS does not limit its focus to production-related aspects and the development of value chains: it also addresses livelihood issues in a broad sense. With its focus on learning processes LforS seeks to create a better understanding of the links between different spheres and different levels of decision-making; it also seeks to foster integration of the different actors’ perspectives.

Vulnerability to risk among small farmers in Tajikistan: results of a 2011 survey

Tajikistan is judged to be highly vulnerable to risk, including food insecurity risks and climate change risks. By some vulnerability measures it is the most vulnerable among all 28 countries in the World Bank’s Europe and Central Asia Region – ECA (World Bank 2009). The rural population, with its relatively high incidence of poverty, is particularly vulnerable. The Pilot Program for Climate Resilience (PPCR) in Tajikistan (2011) provided an opportunity to conduct a farm-level survey with the objective of assessing various dimensions of rural population’s vulnerability to risk and their perception of constraints to farming operations and livelihoods. The survey should be accordingly referred to as the 2011 PPCR survey. The rural population in Tajikistan is highly agrarian, with about 50% of family income deriving from agriculture (see Figure 4.1; also LSMS 2007 – own calculations). Tajikistan’s agriculture basically consists of two groups of producers: small household plots – the successors of Soviet “private agriculture” – and dehkan (or “peasant”) farms – new family farming structures that began to be created under relevant legislation passed after 1992 (Lerman and Sedik, 2008). The household plots manage 20% of arable land and produce 65% of gross agricultural output (GAO). Dehkan farms manage 65% of arable land and produce close to 30% of GAO. The remaining 15% of arable land is held in agricultural enterprises – the rapidly shrinking sector of corporate farms that succeeded the Soviet kolkhozes and sovkhozes and today produces less than 10% of GAO (TajStat 2011) The survey conducted in May 2011 focused on dehkan farms, as budgetary constraints precluded the inclusion of household plots. A total of 142 dehkan farms were surveyed in face-to-face interviews. They were sampled from 17 districts across all four regions – Sughd, Khatlon, RRP, and GBAO. The districts were selected so as to represent different agro-climatic zones, different vulnerability zones (based on the World Bank (2011) vulnerability assessment), and different food-insecurity zones (based on WFP/IPC assessments). Within each district, 3-4 jamoats were chosen at random and 2-3 farms were selected in each jamoat from lists provided by jamoat administration so as to maximize the variability by farm characteristics. The sample design by region/district is presented in Table A, which also shows the agro-climatic zone and the food security phase for each district. The sample districts are superimposed on a map of food security phases based on IPC April 2011.

Two-Year Corneal Cross-Linking Results in Patients Younger than 18 Years with Documented Progressive Keratoconus

To report refractive, topographic, aberrometric, and tomographic outcomes 24 months after corneal cross-linking (CXL) in patients up to 18 years of age with progressive keratoconus.

Impairment of mitochondrial tRNAIle processing by a novel mutation associated with chronic progressive external ophthalmoplegia

We report a sporadic case of chronic progressive external ophthalmoplegia associated with ragged red fibers. The patient presented with enlarged mitochondria with deranged internal architecture and crystalline inclusions. Biochemical studies showed reduced activities of complex I, III and IV in skeletal muscle. Molecular genetic analysis of all mitochondrial tRNAs revealed a G to A transition at nt 4308; the G is a highly conserved nucleotide that participates in a GC base-pair in the T-stem of mammalian mitochondrial tRNA(Ile). The mutation was detected at a high level (approx. 50%) in muscle but not in blood. The mutation co-segregated with the phenotype, as the mutation was absent from blood and muscle in the patient's healthy mother. Functional characterization of the mutation revealed a six-fold reduced rate of tRNA(Ile) precursor 3' end maturation in vitro by tRNAse Z. Furthermore, the mutated tRNA(Ile) displays local structural differences from wild-type. These results suggest that structural perturbations reduce efficiency of tRNA(Ile) precursor 3' end processing and contribute to the molecular pathomechanism of this mutation.

Progressive dopamine and hypocretin deficiencies in Parkinson's disease: is there an impact on sleep and wakefulness?

Sleep-wake disturbances are frequent in patients with Parkinson's disease, but prospective controlled electrophysiological studies of sleep in those patients are surprisingly sparse, and the pathophysiology of sleep-wake disturbances in Parkinson's disease remains largely elusive. In particular, the impact of impaired dopaminergic and hypocretin (orexin) signalling on sleep and wakefulness in Parkinson's disease is still unknown. We performed a prospective, controlled electrophysiological study in patients with early and advanced Parkinson's disease, e.g. in subjects with presumably different levels of dopamine and hypocretin cell loss. We compared sleep laboratory tests and cerebrospinal fluid levels with hypocretin-deficient patients with narcolepsy with cataplexy, and with matched controls. Nocturnal sleep efficiency was most decreased in advanced Parkinson patients, and still lower in early Parkinson patients than in narcolepsy subjects. Excessive daytime sleepiness was most severe in narcolepsy patients. In Parkinson patients, objective sleepiness correlated with decrease of cerebrospinal fluid hypocretin levels, and repeated hypocretin measurements in two Parkinson patients revealed a decrease of levels over years. This suggests that dopamine and hypocretin deficiency differentially affect sleep and wakefulness in Parkinson's disease. Poorer sleep quality is linked to dopamine deficiency and other disease-related factors. Despite hypocretin cell loss in Parkinson's disease being only partial, disturbed hypocretin signalling is likely to contribute to excessive daytime sleepiness in Parkinson patients.

Cardiac tissue-restricted deletion of plakoglobin results in progressive cardiomyopathy and activation of {beta}-catenin signaling

Mutations in the plakoglobin (JUP) gene have been identified in arrhythmogenic right ventricular cardiomyopathy (ARVC) patients. However, the mechanisms underlying plakoglobin dysfunction involved in the pathogenesis of ARVC remain poorly understood. Plakoglobin is a component of both desmosomes and adherens junctions located at the intercalated disc (ICD) of cardiomyocytes, where it functions to link cadherins to the cytoskeleton. In addition, plakoglobin functions as a signaling protein via its ability to modulate the Wnt/beta-catenin signaling pathway. To investigate the role of plakoglobin in ARVC, we generated an inducible cardiorestricted knockout (CKO) of the plakoglobin gene in mice. Plakoglobin CKO mice exhibited progressive loss of cardiac myocytes, extensive inflammatory infiltration, fibrous tissue replacement, and cardiac dysfunction similar to those of ARVC patients. Desmosomal proteins from the ICD were decreased, consistent with altered desmosome ultrastructure in plakoglobin CKO hearts. Despite gap junction remodeling, plakoglobin CKO hearts were refractory to induced arrhythmias. Ablation of plakoglobin caused increase beta-catenin stabilization associated with activated AKT and inhibition of glycogen synthase kinase 3beta. Finally, beta-catenin/TCF transcriptional activity may contribute to the cardiac hypertrophy response in plakoglobin CKO mice. This novel model of ARVC demonstrates for the first time how plakoglobin affects beta-catenin activity in the heart and its implications for disease pathogenesis.

Novel mutations consolidate KCTD7 as a progressive myoclonus epilepsy gene

The progressive myoclonus epilepsies (PMEs) comprise a group of clinically and genetically heterogeneous disorders characterised by myoclonus, epilepsy, and neurological deterioration. This study aimed to identify the underlying gene(s) in childhood onset PME patients with unknown molecular genetic background.