Angelique Corthals

Forests and drugs: coca-driven deforestation in tropical biodiversity hotspots.

Identifying drivers of deforestation in tropical biodiversity hotspots is critical to assess threats to particular ecosystems and species and proactively plan for conservation. We analyzed land cover change between 2002 and 2007 in the northern Andes, Chocó, and Amazon forests of Colombia, the largest producer of coca leaf for the global cocaine market, to quantify the impact of this illicit crop on forest dynamics, evaluate the effectiveness of protected areas in this context, and determine the effects of eradication on deforestation. Landscape-level analyses of forest conversion revealed that proximity to new coca plots and a greater proportion of an area planted with coca increased the probability of forest loss in southern Colombia, even after accounting for other covariates and spatial autocorrelation. We also showed that protected areas successfully reduced forest conversion in coca-growing regions. Neither eradication nor coca cultivation predicted deforestation rates across municipalities. Instead, the presence of new coca cultivation was an indicator of municipalities, where increasing population led to higher deforestation rates. We hypothesize that poor rural development underlies the relationship between population density and deforestation in coca-growing areas. Conservation in Colombias vast forest frontier, which overlaps with its coca frontier, requires a mix of protected areas and strategic rural development to succeed.

Multiple Sclerosis is Not a Disease of the Immune System

Multiple sclerosis is a complex neurodegenerative disease, thought to arise through autoimmunity against antigens of the central nervous system. The autoimmunity hypothesis fails to explain why genetic and environmental risk factors linked to the disease in one population tend to be unimportant in other populations. Despite great advances in documenting the cell and molecular mechanisms underlying MS pathophysiology, the autoimmunity framework has also been unable to develop a comprehensive explanation of the etiology of the disease. I propose a new framework for understanding MS as a dysfunction of the metabolism of lipids. Specifically, the homeostasis of lipid metabolism collapses during acute-phase inflammatory response triggered by a pathogen, trauma, or stress, starting a feedback loop of increased oxidative stress, inflammatory response, and proliferation of cytoxic foam cells that cross the blood brain barrier and both catabolize myelin and prevent remyelination. Understanding MS as a chronic metabolic disorder illuminates four aspects of disease onset and progression: 1) its pathophysiology; 2) genetic susceptibility; 3) environmental and pathogen triggers; and 4) the skewed sex ratio of patients. It also suggests new avenues for treatment.

Detecting the immune system response of a 500 year-old Inca mummy.

Disease detection in historical samples currently relies on DNA extraction and amplification, or immunoassays. These techniques only establish pathogen presence rather than active disease. We report the first use of shotgun proteomics to detect the protein expression profile of buccal swabs and cloth samples from two 500-year-old Andean mummies. The profile of one of the mummies is consistent with immune system response to severe pulmonary bacterial infection at the time of death. Presence of a probably pathogenic Mycobacterium sp. in one buccal swab was confirmed by DNA amplification, sequencing, and phylogenetic analyses. Our study provides positive evidence of active pathogenic infection in an ancient sample for the first time. The protocol introduced here is less susceptible to contamination than DNA-based or immunoassay-based studies. In scarce forensic samples, shotgun proteomics narrows the range of pathogens to detect using DNA assays, reducing cost. This analytical technique can be broadly applied for detecting infection in ancient samples to answer questions on the historical ecology of specific pathogens, as well as in medico-legal cases when active pathogenic infection is suspected.

An Application of Tissue and DNA Banking for Genomics and Conservation: The Ambrose Monell Cryo-Collection (AMCC)

With the advent of the so-called genomic revolution and improved techniques of DNA analysis, combined with a rapidly vanishing biodiversity, the systematic community has been facing a remarkable—and often neglected—challenge for the past 50 years: to preserve genetic resources issued from research. The preservation and long-term storage of biological specimens’ derived materials (e.g., DNA extracts) and associated data are essential to ensure comparability and reproducibility in all areas of biological research. Natural history museums and herbaria around the world are now in a position to face the exciting and challenging task of preserving the genetic library of life for generations to come. However, the lack and/or poor condition of preservation of molecular vouchers generated from often fragile and rare specimens have been problems too often underestimated or unable to be addressed due to lack of funding or, more pointedly, lack of interest in preservation of these important research materials. The present article does not seek to reiterate the plea for genetic resource collections introduce by Dessauer et al. in 1984 (and more recently by Sheldon, 2001, and Savolainen and Reeves, 2004). It seeks to bring these collections, and the issues of preservation of genetic resources, to the awareness of the systematic biology community through the case study of the American Museum of Natural History new cryogenic repository, the Ambrose Monell Collection for Molecular and Microbial Research (AMCC; website: http://research.amnh.org/ amcc/).

A new species of Lonchophylla (Chiroptera: Phyllostomidae) from the eastern Andes of northwestern South America

Abstract Since 2004 five new species have been described in the nectar-feeding phyllostomid bat genus Lonchophylla. All the new species are endemic to one Neotropical ecoregion, suggesting that more species remain to be discovered among collected specimens currently referred to several widespread taxa. Herein we describe a new species, Lonchophylla orienticollina, endemic to the middle elevations of the eastern Andes of Venezuela, Colombia, and Ecuador. The new species superficially resembles its sympatric congener L. robusta, but its cranial morphology and combination of measurements are distinctive. Throughout its range, L. orienticollina is sympatric with L. robusta, and it also overlaps with L. handleyi in the Cordillera Oriental of Ecuador. The evolutionary processes leading to the divergence among Lonchophylla species, as well as the ecological mechanisms that enable multiple, subtly different species to coexist will remain obscure without new field and phylogenetic studies.

From the Field to the Lab: Best Practices for Field Preservation of Bat Specimens for Molecular Analyses

Studies in molecular ecology depend on field-collected samples for genetic information, and the tissue sampled and preservation conditions strongly affect the quality of the DNA obtained. DNA yields from different tissue types have seldom been compared, and the relative performance of storage media has never been directly tested, even though these media may influence DNA degradation under field conditions. We analyzed DNA yield from buccal swabs and wing punches harvested from live bats using nucleic acid quantification as well as quantitative PCR for a single-copy nuclear locus. We also compared DNA yields from wing tissue preserved in three media: ethanol, NaCl-saturated dimethyl sulfoxide (DMSO), and silica desiccant. Wing punches yielded more total DNA than did buccal swabs, and wing tissues preserved in silica beads yielded significantly more total and nuclear DNA than those preserved in DMSO or ethanol. These results show that tissue type and preservation media strongly influence the quantity of DNA obtained from non-lethal genetic samples, and based on these effects we provide recommendations for field collection of tissues for genetic analyses.