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The Mesoamerican (MA) gene pool of lima bean ( Phaseolus lunatus L.) is widely distributed from northern Mexico to northern Argentina in its wild forms and from the southern United States to the east coast of Brazil in its domesticated forms. This broad distribution and lack of wild accessions of the MA gene pool in many areas of its natural distribution has impeded determining its center of domestication and establishing whether it has a single or multiple centers. To answer these questions, we evaluated 262 accessions of P. lunatus using two intergenic spacers of chloroplast DNA: atpB- rbcL and trnL- trnF. The data were analyzed using a maximum likelihood tree (ML), a haplotype network and two estimators of genetic differentiation ( N and G). Nucleotide diversity (π) and haplotype (Hd) were quantified to estimate the percentage of reduction in genetic diversity (%r) as a founder effect. The ML tree and haplotype network indicated the existence of three groups (AI, MI and MII), which was supported by the high values of N (0.61-0.80). Values for %r were high (58.67-60.83 %). Existence of Mesoamerican and Andean gene pools was confirmed, with two genetically and geographically distinct groups (MI and MII) within the MA gene pool. We present the first evidence for multiple origins of domestication for the MA gene pool. For MI, we propose western central Mexico as the domestication area and between Guatemala and Costa Rica for MII. We observed a founder effect in the MA gene pool as a result of domestication. [ABSTRACT FROM AUTHOR]

Genetic erosion has been evaluated at the landrace level in the past, principally because the loss of landraces is believed to generate erosion at the allelic level; however, few studies had tested this hypothesis in the crop's centers of diversity and domestication. Using microsatellite markers, we analyzed for genetic erosion in lima bean ( Phaseolus lunatus) landraces over time in samples collected in 1979 and in 2007 in northeast Campeche, in the Yucatan peninsula, Mexico, an important diversity center and part of the putative domestication area for this crop. We found that the lima bean genetic pool from 1979 had a higher genetic diversity than the one for the 2007 pool (Nei's diversity, H = 0.18 and 0.05, respectively). Although this result could not to be explained using a bottleneck analysis, a cluster analysis showed that the alleles present in 1979 were not the same as those found in 2007, indicating an allelic displacement in the genetic pool of the lima bean landraces in the last 30 years. This displacement could be due to the introduction of improved varieties or landraces, resulting in a displacement of local varieties or to changes in the Mayan criteria for selection of germplasm or both. This study showed that the loss of landraces can generate both quantitative and qualitative changes in the genetic pool of the domesticated species. Such changes are very important to consider when planning ex situ and in situ programs to conserve crop diversity in their domestication areas. [ABSTRACT FROM AUTHOR]

The goal of the present study was to determine whether mitoxantrone would impair wound healing to a similar degree as doxorubicin when given in equally cytotoxic doses. On day 0, male Fischer rats were wounded and treated with 5% dextrose (control), 6 mg/kg doxorubicin, or 1.2 or 2.4 mg/kg mitoxantrone. On day 5, WBCs for the doxorubicin group and the group that had been treated with 1.2 mg/kg mitoxantrone were 33% and 43% lower than control values, respectively. All rats that had been given 2.4 mg/kg mitoxantrone died within 1 week of being wounded due to drug toxicity. On day 21, wound-breaking strength (WBS) analysis was performed: two skin specimens were taken from each dorsal skin incision perpendicular to the scar axis and were subjected to wound disruption (grams of force) by uniaxial extension. The WBS analysis indicated significant differences between the doxorubicin treated group (1183 +/- 96 g) and the control group (2422 +/- 247 g). However, no significant difference was found between the group that had been given 1.2 mg/kg mitoxantrone (2140 +/- 191 g) and control animals. Thus, mitoxantrone seems to exert myelosuppressive effects similar to those displayed by doxorubicin, but the former drug results in significantly less impairment of wound healing in the rat model. [ABSTRACT FROM AUTHOR]