Nut production in Bertholletia excelsa across a logged forest mosaic: implications for multiple forest use

Although many examples of multiple-use forest management may be found in tropical smallholder systems, few studies provide empirical support for the integration of selective timber harvesting with non-timber forest product (NTFP) extraction. Brazil nut (Bertholletia excelsa, Lecythidaceae) is one of the world’s most economically-important NTFP species extracted almost entirely from natural forests across the Amazon Basin. An obligate out-crosser, Brazil nut flowers are pollinated by large-bodied bees, a process resulting in a hard round fruit that takes up to 14 months to mature. As many smallholders turn to the financial security provided by timber, Brazil nut fruits are increasingly being harvested in logged forests. We tested the influence of tree and stand-level covariates (distance to nearest cut stump and local logging intensity) on total nut production at the individual tree level in five recently logged Brazil nut concessions covering about 4000 ha of forest in Madre de Dios, Peru. Our field team accompanied Brazil nut harvesters during the traditional harvest period (January-April 2012 and January-April 2013) in order to collect data on fruit production. Three hundred and ninety-nine (approximately 80%) of the 499 trees included in this study were at least 100 m from the nearest cut stump, suggesting that concessionaires avoid logging near adult Brazil nut trees. Yet even for those trees on the edge of logging gaps, distance to nearest cut stump and local logging intensity did not have a statistically significant influence on Brazil nut production at the applied logging intensities (typically 1–2 timber trees removed per ha). In one concession where at least 4 trees ha-1 were removed, however, the logging intensity covariate resulted in a marginally significant (0.09) P value, highlighting a potential risk for a drop in nut production at higher intensities. While we do not suggest that logging activities should be completely avoided in Brazil nut rich forests, when a buffer zone cannot be observed, low logging intensities should be implemented. The sustainability of this integrated management system will ultimately depend on a complex series of socioeconomic and ecological interactions. Yet we submit that our study provides an important initial step in understanding the compatibility of timber harvesting with a high value NTFP, potentially allowing for diversification of forest use strategies in Amazonian Perù

Epidemiological and Molecular Characterization of a Mexican Population Isolate with High Prevalence of Limb-Girdle Muscular Dystrophy Type 2A Due to a Novel <i>Calpain-3</i> Mutation

<div><p>Limb-Girdle Muscular Dystrophy type 2 (LGMD2) is a group of autosomally recessive inherited disorders defined by weakness and wasting of the shoulder and pelvic girdle muscles. In the past, several population isolates with high incidence of LGMD2 arising from founder mutation effects have been identified. The aim of this work is to describe the results of clinical, epidemiologic, and molecular studies performed in a Mexican village segregating numerous cases of LGMD2. A population census was conducted in the village to identify all LGMD affected patients. Molecular analysis included genome wide homozygosity mapping using a 250K SNP Affymetrix microarray followed by PCR amplification and direct nucleotide sequencing of the candidate gene. In addition, DNA from 401 randomly selected unaffected villagers was analyzed to establish the carrier frequency of the LGMD2 causal mutation. A total of 32 LGMD2 patients were identified in the village, rendering a disease prevalence of 4.3 (CI: 2.9–5.9) cases per 1,000 habitants (1 in 232). Genome wide homozygosity mapping revealed that affected individuals shared a 6.6 Mb region of homozygosity at chromosome 15q15. The identified homozygous interval contained <i>CAPN3</i>, the gene responsible for LGMD2 type A (LGMD2A). Direct sequencing of this gene revealed homozygosity for a novel c.348C>A mutation (p.Ala116Asp) in DNA from all 20 affected subjects available for genetic screening, except one which was heterozygous for the mutation. In such patient, a heterozygous c.2362AG>TCATCT deletion/insertion was recognized as the second <i>CAPN3</i> mutation. Western blot and autocatalytic activity analyses in protein lysates from skeletal muscle biopsy obtained from a p.Ala116Asp homozygous patient suggested that this particular mutation increased the autocatalytic activity of CAPN3. Thirty eigth heterozygotes of the p.Ala116Asp mutation were identified among 401 genotyped unaffected villagers, yielding a population carrier frequency of 1 in 11. This study demonstrates that a cluster of patients with LGMD2A in a small Mexican village arises from a novel <i>CAPN3</i> founder mutation. Evidence of allelic heterogeneity is demonstrated by the recognition of an additional <i>CAPN3</i> mutation in a single affected. Our study provides an additional example of genetic isolation causing a high prevalence of LGMD and of successful molecular characterization of the disease by means of homozygosity mapping. The identification of a very high carrier frequency of the LGMD2-causing mutation has implications for more rational genetic counseling in this community.</p></div

Variable clinical phenotype in LGMD2 patients.

<p>(A) Severe winged scapulae are evident in a 22-year- old male patient. (B) Dorso-lumbar scoliosis is observed in a patient aged 25 years.</p

Partial nucleotide sequence of the CAPN3 gene.

<p>(A) Normal sequence showing homozygosity for the wild type GCC (alanine) codon at position 116. (B) Sequence from a heterozygous (GCC/GAC) subject (C) Sequence in DNA from a homozygous mutant (GAC/GAC) LGMD2 subject. The arrow indicates the mutated nucleotide (c.348C>A).</p

Genome-wide homozygosity analysis in LGMD2.

<p>Genotypes obtained with the Affymetrix 250K SNPs chip were analyzed with the HomozygosityMapper software for the identification of large regions of homozygosity. Top bars indicate homozygous regions identified in pooled DNA from three affected patients. As shown in the screen shot, two chromosomal regions of maximal homozygosity were identified. The largest region (6.6 Mb) corresponded to chromosome 15q (pointed with a blue arrow), from nucleotide 39,911,352 to nucleotide 46,517,283, and includes the <i>CAPN3</i> gene.</p

Clinical characteristics of 20 LGMD2 patients clinically examined in the village.

<p>Clinical characteristics of 20 LGMD2 patients clinically examined in the village.</p