A Gly98Val Mutation in the N-Myc Downstream Regulated Gene 1 (NDRG1) in Alaskan Malamutes with Polyneuropathy

The first cases of early-onset progressive polyneuropathy appeared in the Alaskan Malamute population in Norway in the late 1970s. Affected dogs were of both sexes and were ambulatory paraparetic, progressing to non-ambulatory tetraparesis. On neurologic examination, affected dogs displayed predominantly laryngeal paresis, decreased postural reactions, decreased spinal reflexes and muscle atrophy. The disease was considered eradicated through breeding programmes but recently new cases have occurred in the Nordic countries and the USA. The N-myc downstream-regulated gene (NDRG1) is implicated in neuropathies with comparable symptoms or clinical signs both in humans and in Greyhound dogs. This gene was therefore considered a candidate gene for the polyneuropathy in Alaskan Malamutes. The coding sequence of the NDRG1 gene derived from one healthy and one affected Alaskan Malamute revealed a non-synonymous G>T mutation in exon 4 in the affected dog that causes a Gly98Val amino acid substitution. This substitution was categorized to be “probably damaging” to the protein function by PolyPhen2 (score: 1.000). Subsequently, 102 Alaskan Malamutes from the Nordic countries and the USA known to be either affected (n = 22), obligate carriers (n = 7) or healthy (n = 73) were genotyped for the SNP using TaqMan. All affected dogs had the T/T genotype, the obligate carriers had the G/T genotype and the healthy dogs had the G/G genotype except for 13 who had the G/T genotype. A protein alignment showed that residue 98 is conserved in mammals and also that the entire NDRG1 protein is highly conserved (94.7%) in mammals. We conclude that the G>T substitution is most likely the mutation that causes polyneuropathy in Alaskan Malamutes. Our characterization of a novel candidate causative mutation for polyneuropathy offers a new canine model that can provide further insight into pathobiology and therapy of human polyneuropathy. Furthermore, selection against this mutation can now be used to eliminate the disease in Alaskan Malamutes.     

Ecosystem Service Provision by Secondary Forests in Shifting Cultivation Areas Remains Poorly Understood

Human Ecology - It is often asserted that secondary forests (SF) provide inferior forest-based ecosystem services (ES), but there is limited research to generalize this claim. Here, we review...     

Patterns of species richness in dry grassland patches in an agricultural landscape

Eighty-five patches of semi-natural grassland of varying size scattered in a agricultural landscape were investigated for their flora of vascular plants. Relationships between species richness and patch area, spatial isolation and local habitat conditions including heterogeneity were examined. Differences between single species and among groups of species defined by life-history traits were also investigated.
Area was shown to be an important determinant of species richness irrespective of habitat heterogeneity. Isolation in space and habitat heterogeneity also play significant roles. These results are consistent with results from a multitude of studies on fragments of ancient deciduous woodland in northern Europe, They are, however, contradictory to results from previous studies in grasslands within the same region. Seed mass and dispersal syndrome were poor predictors of the degree to which the species were affected by isolation of grassland patches. Seed mass deviation from community median could explain a small percentage of the variation in regional abundance. Logistic regression on species occurrences showed that few species are associated with large patches, and less than half seem to avoid isolated patches.     

Soil greenhouse gas emissions from inorganic fertilizers and recycled oil palm waste products from Indonesian oil palm plantations

A continuous rise in the global demand for palm oil has resulted in the large‐scale expansion of oil palm plantations and generated environmental controversy. Efforts to increase the sustainability of oil palm cultivation include the recycling of oil mill and pruning residues in the field, but this may increase soil methane (CH₄) emissions. This study reports the results of yearlong field‐based measurements of soil nitrous oxide (N₂O) and CH₄ emissions from commercial plantations in North Sumatra, Indonesia. One experiment investigated the effects of soil‐water saturation on N₂O and CH₄ emissions from inorganic fertilizers and organic amendments by simulating 25 mm rainfall per day for 21 days. Three additional experiments focused on emissions from (a) inorganic fertilizer (urea), (b) combination of enriched mulch with urea and (c) organic amendments (empty fruit bunches, enriched mulch and pruned oil palm fronds) applied in different doses and spatial layouts (placed in inter‐row zones, piles, patches or bands) for a full year. The higher dose of urea led to a significantly higher N₂O emissions with the emission factors ranging from 2.4% to 2.7% in the long‐term experiment, which is considerably higher than the IPCC standard of 1%. Organic amendments were a significant source of both N₂O and CH₄ emissions, but N₂O emissions from organic amendments were 66%–86% lower than those from inorganic fertilizers. Organic amendments applied in piles emitted 63% and 71% more N₂O and CH₄, respectively, than when spread out. With twice the dose of organic amendments, cumulative emissions were up to three times greater. The (simulated) rainwater experiment showed that the increase in precipitation led to a significant increase in N₂O emissions significantly, suggesting that the time of fertilization is a critical management option for reducing emissions. The results from this study could therefore help guide residue and nutrient management practices to reduce emissions while ensuring better nutrient recycling for sustainable oil palm production systems.     

Cross-reactive antigen recognition by an encephalitogenic T cell receptor. Implications for T cell biology and autoimmunity.

The dominant immune response to rat myelin basic protein in H-2u mice is directed against the acetylated, N-terminal peptide Ac1-11 (AcASQKR-PSQRHG). This peptide causes encephalomyelitis on injection into mice of the H-2u haplotype. Only two residues of the peptide are required for ligation of the TCR from an Ac1-11-specific T cell hybridoma. Proline at position 6 could not be substituted by any other L-amino acid, whereas glutamine at position 3 could be replaced by phenylalanine, histidine, methionine, or tyrosine. Cross-reactive recognition of these residues appears to be specific, because increasing the affinity of each analogue for its MHC restriction element, by replacing lysine with tyrosine at position 4, did not alter the pattern of cross-reactivity. For the majority of substitutions at this position, a lack of stimulation could not be explained by failure to bind to I-Au. However, competition binding studies showed that introduction of proline at position 3 reduced the efficacy of binding to I-Au. Cross-reactive analogues of Ac1-11 were injected into H-2u mice to test the extent to which cross-reactive T cell activation might lead to autoimmune disease in this model. An analogue containing methionine at position 3 caused clinical experimental autoimmune encephalomyelitis in a small percentage of H-2u mice.     

Fish, marine n-3 polyunsaturated fatty acids and coronary heart disease: a minireview with focus on clinical trial data

In this paper, we will briefly deal with the background for the possible effects of long-chain marine n-3 (also called omega-3) polyunsaturated fatty acids (PUFA) in coronary heart disease (CHD) and then focus on findings from clinical trials in humans. We will not deal with effects of alpha-linolenic acid, the non-marine type of n-3 PUFA derived from plant oils.     

Copper Resistance in Enterococcus faecium, Mediated by the tcrB Gene, Is Selected by Supplementation of Pig Feed with Copper Sulfate

The tcr gene cluster mediates in vitro copper resistance in Enterococcus faecium. Here we describe the selection of tcr-mediated copper resistance in E. faecium in an animal feeding experiment with young pigs fed 175 mg copper/kg feed (ppm), which is the concentration commonly used for piglets in European pig production. tcr-mediated copper resistance was not selected for in a control group fed low levels of copper (6 ppm). We also show coselection of macrolide- and glycopeptide-resistant E. faecium in the animal group fed the high level of copper. Finally, we identify the tcr genes in the enterococcal species E. mundtii, E. casseliflavus, and E. gallinarum for the first time.