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Emanuel L. Johnson - One of the best experts on this subject based on the ideXlab platform.

  • Inter- and Intra-specific Variation among Five Erythroxylum Taxa Assessed by AFLP
    Annals of botany, 2005
    Co-Authors: Emanuel L. Johnson, Dapeng Zhang, Stephen D. Emche
    Abstract:

    • Background and Aims The four cultivated Erythroxylum taxa (E. Coca var. Coca, E. novogranatense var. novogranatense, E. Coca var. ipadu and E. novogranatense var. truxillense) are indigenous to the Andean region of South America and have been cultivated for folk-medicine and, within the last century, for illicit Cocaine production. The objective of this research was to assess the structure of genetic diversity within and among the four cultivated alkaloid-bearing taxa of Erythroxylum in the living collection at Beltsville Agricultural Research Center. • Methods Amplified fragment length polymorphism (AFLP) fingerprinting was performed in 86 Erythroxylum accessions using a capillary genotyping system. Cluster analysis, multidimensional scaling (MDS) and analysis of molecular variance (AMOVA) were used to assess the pattern and level of genetic variation among and within the taxa. • Key Results A clear distinction was revealed between E. Coca and E. novogranatense. At the intra-specific level, significant differentiation was observed between E. c. var. Coca and E. c. var. ipadu, but the differentiation between E. n. var. novogranatense and E. n. var. truxillense was negligible. Erythroxylum c. var. ipadu had a significantly lower amount of diversity than the E. c. var. Coca and is genetically different from the E. c. var. ipadu currently under cultivation in Colombia, South America. • Conclusions There is a heterogeneous genetic structure among the cultivated Erythroxylum taxa where E. Coca and E. novogranatense are two independent species. Erythroxylum Coca var. Coca is most likely the ancestral taxon of E. c. var. ipadu and a founder effect may have occurred as E. c. var. ipadu moved from the eastern Andes in Peru and Bolivia into the lowland Amazonian basin. There is an indication of artificial hybridization in Coca grown in Colombia.

  • identification of erythroxylum taxa by aflp dna analysis
    Phytochemistry, 2003
    Co-Authors: Emanuel L. Johnson, James A Saunders, Sue Mischke, Charles S Helling, Stephen D. Emche
    Abstract:

    Abstract Erythroxylum Coca , indigenous to the Andean region of South America, is grown historically as a source of homeopathic medicine. However, in the last century, cultivation of E. Coca and several closely-related species for the production of illicit Cocaine has become a major global problem. Two subspecies, E. Coca var. Coca and E. Coca var. ipadu , are almost indistinguishable phenotypically; a related Cocaine-bearing species also has two subspecies ( E. novogranatense var. novogranatense and E. novogranatense var. truxillense ) that are phenotypically similar, but morphologically distinguishable. The purpose of this research was to discover unique AFLP DNA patterns (“genetic fingerprinting”) that characterize the four taxa and then, if successful, to evaluate this approach for positive identification of the various species of Coca. Of seven different AFLP primer pairs tested, a combination of five proved optimal in differentiating the four taxa as well as a non-Cocaine-bearing species, E. aerolatum . This method of DNA fragment separation was selective, and faster, for Coca identification, compared with analyses based on flavonoid chemotaxonomy. Using the 5-primer AFLP approach, 132 known and unknown Coca leaf accessions were evaluated. Of these, 38 were collected in 1997–2001 from illicit Coca fields in Colombia, and all were genetically differentiated from Coca originating in Peru and Bolivia. Based on the DNA profiling, we believe that the Colombian Coca now represents a hybridization of E. Coca var. ipadu . Geographical profiling within Colombia also seems feasible as new Coca production areas are developed or new types of Coca are introduced within traditional growing areas.

  • Alkaloid content in two Erythroxylum taxa during juvenile growth and development
    Journal of Herbs Spices & Medicinal Plants, 2003
    Co-Authors: Emanuel L. Johnson
    Abstract:

    ABSTRACT Erythroxylum Coca var. Coca Lam. And Erythroxylum novogranatense var. novogranatense (Morris) Hieron (E.n. var. novogranatense) were grown in a controlled environment for 52 weeks to monitor the content of hygrine, tropinone, tropaCocaine, methyl ecgonine, Cocaine and cis- and trans-cinnamoylCocaine in seeds, plant parts, and organs during juvenile growth. Embryos and endosperms of var. Coca contained Cocaine while only embryos of var. novogranatense contained Cocaine. TropaCocaine was present in hypocotyls, stems and roots of var. novogranatense, but not in var. Coca. Trans-cinnamoylCocaine was the most abundant alkaloid in cotyledons (12 weeks after seeding) and leaves (24 weeks after seeding) in both var. Coca and var. novogranatense. After 52 weeks of seeding growth, Cocaine was the preeminent alkaloid in leaves of both taxons with a Cocaine content of 0.66 percent in var. Coca and 1.04 percent in var. novogranatense.

  • Leaf Flavonoids as Chemotaxonomic Markers for Two Erythroxylum Taxa
    Zeitschrift für Naturforschung C, 1997
    Co-Authors: Emanuel L. Johnson, Walter F. Schmidt, Helen A. Norman
    Abstract:

    Leaf extracts of Erythroxylum Coca var. Coca Lam. (E. c. var. Coca) yielded six O-eonjugates of Eriodictyol flavonoids, while the equivalent extracts from Erythroxylum novogranatense var. novogranatense (Morris) Hieron (E. n. var. novogranatense) contained five flavonoids, two of which were O-conjugates of Luteolin and three were O-conjugates of Kaempferol. All six of E. c. var. Coca methanolic extracted peaks (resolved by HPLC) were found to have a 2, 3 single bond, which in E. n. var. novogranatense is replaced by a 2- hydroxy allene. The other primary difference in the predominant flavonoids between these taxa is the chemical composition of the sugar and/or acyl O-conjugation and site(s) at which this conjugation occurred. The results suggest that the most abundant O-conjugated flavonoids of E. c. var. Coca and E. n. var. novogranatense may be used as chemotaxonomic markers for the two taxa. Therefore, the O-conjugated peaks of Eriodictyol , are distinct chemotaxonomic markers for E. c. var. Coca and the O-conjugated peaks Luteolin and Kaempferol for E. n. var. novogranatense. These taxa are two of the four cultivated Erythroxylum taxa that contain commercial quantities of the Cocaine alkaloid in their leaves, this entity also sets apart the taxa from other members of Erythroxylum. We suggest that the biochemistry of flavonoids of other Erythroxylum taxa may also be species selective

  • Effect of soil pH on mineral element concentrations of two Erythroxylum species
    Journal of Plant Nutrition, 1997
    Co-Authors: Emanuel L. Johnson, T. A. Campbell, C. D. Foy
    Abstract:

    Abstract Erythroxylum Coca var. Coca Lam. (E. Coca) and Erythroxylum novogranatense var. novogranatense (Morris) Hieron (E. n. novogranatense) are two of four Erythroxylum species grown in the tropics of South America for cultural medicines and the alkaloid benzoylmethylecgonine. In a published study of biomass production over a soil pH range of 3.5 to 7.0, E. Coca grew best at a pH equal to and below 5.5, and E. n. novogranatense grew best within the pH range of 4.7 to 6.0. Erythroxylum Coca was tentatively classified as more tolerant to metal toxicities [aluminum (Al) and manganese (Mn)] than E. n. novogranatense, however, concentration patterns of mineral elements for E. Coca and E. n. novogranatense tissue have not been reported, nor have the mechanisms of differential acid‐soil‐tolerance been elucidated. In the current study, the effects of soil pH on concentrations of Al, calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), Mn, and zinc (Zn) in leaves, stems, and roots were investiga...

J Lydon - One of the best experts on this subject based on the ideXlab platform.

Fredrik Carlsson - One of the best experts on this subject based on the ideXlab platform.

  • a survey based choice experiment on Coca cultivation
    Journal of Development Economics, 2010
    Co-Authors: Marcela Ibanez, Fredrik Carlsson
    Abstract:

    From 1997 to 2005, an astonishing 5200 million USD was invested to reduce Cocaine production in Colombia, the world's main Cocaine producer. However, little is known about the effectiveness of policies targeting Coca cultivation. This paper uses a survey-based experiment to evaluate the effects of the two main policies: eradication and alternative development programs. Our results support Becker's (1968) model of crime participation and in addition shed light on other non-monetary factors that affect the Coca cultivation decision: religion, legitimacy, remoteness, and poverty are found to be important. We find that Coca cultivation is inelastic to increases in perceived risk and relative profit so eradication and alternative development would have a rather small effect on Coca cultivation. A simple simulation exercise predicts that investing additional hundred thousand dollars in eradication decreases Coca cultivation in only 1.5%. (C) 2009 Elsevier B.V. All rights reserved. (Less)

  • a survey based choice experiment on Coca cultivation
    Research Papers in Economics, 2009
    Co-Authors: Marcela Ibanez, Fredrik Carlsson
    Abstract:

    From 1997 to 2005, an astonishing 5,200 million USD was invested to reduce Cocaine production in Colombia, the world’s main Cocaine producer. However, little is known about the effectiveness of policies targeting Coca cultivation. This paper uses a surveybased experiment to evaluate the effects of the two main policies: eradication and alternative development programs. Our results support Becker’s (1968) model of crime participation and in addition shed light on other non-monetary factors that affect the Coca cultivation decision: religion, legitimacy, remoteness, and poverty are found to be important. We find that Coca cultivation is inelastic to increases in perceived risk and relative profit so eradication and alternative development would have a rather small effect on Coca cultivation. A simple simulation exercise predicts that investing additional hundred thousand dollars in eradication decreases Coca cultivation in only 1.5%.

Stephen D. Emche - One of the best experts on this subject based on the ideXlab platform.

  • Inter- and Intra-specific Variation among Five Erythroxylum Taxa Assessed by AFLP
    Annals of botany, 2005
    Co-Authors: Emanuel L. Johnson, Dapeng Zhang, Stephen D. Emche
    Abstract:

    • Background and Aims The four cultivated Erythroxylum taxa (E. Coca var. Coca, E. novogranatense var. novogranatense, E. Coca var. ipadu and E. novogranatense var. truxillense) are indigenous to the Andean region of South America and have been cultivated for folk-medicine and, within the last century, for illicit Cocaine production. The objective of this research was to assess the structure of genetic diversity within and among the four cultivated alkaloid-bearing taxa of Erythroxylum in the living collection at Beltsville Agricultural Research Center. • Methods Amplified fragment length polymorphism (AFLP) fingerprinting was performed in 86 Erythroxylum accessions using a capillary genotyping system. Cluster analysis, multidimensional scaling (MDS) and analysis of molecular variance (AMOVA) were used to assess the pattern and level of genetic variation among and within the taxa. • Key Results A clear distinction was revealed between E. Coca and E. novogranatense. At the intra-specific level, significant differentiation was observed between E. c. var. Coca and E. c. var. ipadu, but the differentiation between E. n. var. novogranatense and E. n. var. truxillense was negligible. Erythroxylum c. var. ipadu had a significantly lower amount of diversity than the E. c. var. Coca and is genetically different from the E. c. var. ipadu currently under cultivation in Colombia, South America. • Conclusions There is a heterogeneous genetic structure among the cultivated Erythroxylum taxa where E. Coca and E. novogranatense are two independent species. Erythroxylum Coca var. Coca is most likely the ancestral taxon of E. c. var. ipadu and a founder effect may have occurred as E. c. var. ipadu moved from the eastern Andes in Peru and Bolivia into the lowland Amazonian basin. There is an indication of artificial hybridization in Coca grown in Colombia.

  • identification of erythroxylum taxa by aflp dna analysis
    Phytochemistry, 2003
    Co-Authors: Emanuel L. Johnson, James A Saunders, Sue Mischke, Charles S Helling, Stephen D. Emche
    Abstract:

    Abstract Erythroxylum Coca , indigenous to the Andean region of South America, is grown historically as a source of homeopathic medicine. However, in the last century, cultivation of E. Coca and several closely-related species for the production of illicit Cocaine has become a major global problem. Two subspecies, E. Coca var. Coca and E. Coca var. ipadu , are almost indistinguishable phenotypically; a related Cocaine-bearing species also has two subspecies ( E. novogranatense var. novogranatense and E. novogranatense var. truxillense ) that are phenotypically similar, but morphologically distinguishable. The purpose of this research was to discover unique AFLP DNA patterns (“genetic fingerprinting”) that characterize the four taxa and then, if successful, to evaluate this approach for positive identification of the various species of Coca. Of seven different AFLP primer pairs tested, a combination of five proved optimal in differentiating the four taxa as well as a non-Cocaine-bearing species, E. aerolatum . This method of DNA fragment separation was selective, and faster, for Coca identification, compared with analyses based on flavonoid chemotaxonomy. Using the 5-primer AFLP approach, 132 known and unknown Coca leaf accessions were evaluated. Of these, 38 were collected in 1997–2001 from illicit Coca fields in Colombia, and all were genetically differentiated from Coca originating in Peru and Bolivia. Based on the DNA profiling, we believe that the Colombian Coca now represents a hybridization of E. Coca var. ipadu . Geographical profiling within Colombia also seems feasible as new Coca production areas are developed or new types of Coca are introduced within traditional growing areas.

Francisco Baca-dejo - One of the best experts on this subject based on the ideXlab platform.