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1.  Identification of Stylosanthes guianensis varieties using molecular genetic analysis 
AoB Plants  2012;2012:pls001.
Molecular genetic diversity and population structure analysis were used to clarify the controversial botanical classification of Stylosanthes guianensis. The accessions were clustered in nine groups, each of which was mainly composed of only one of the four botanical varieties.
Background and aims
The botanical classification of Stylosanthes guianensis is controversial, and few studies have used molecular markers to analyse this species. We used microsatellite markers to study the genetic diversity and population structure of S. guianensis and compare our results with the current infraspecific botanical classification.
Methodology
A representative sample from the S. guianensis Brazilian germplasm collection (150 accessions) was analysed using 20 microsatellite loci. A model-based Bayesian approach implemented in the software STRUCTURE was used to assign accessions into clusters. A dendrogram was constructed based on Roger's genetic distances.
Principal results
The number of alleles per locus varied from 2 to 11, with an average of 4.7. The observed (HO) and expected (HE) heterozygosity values varied from 0 to 0.58 (mean of 0.18) and from 0.04 to 0.83 (mean of 0.55), respectively. Nine groups were assembled in STRUCTURE, and these groups were consistent with clusters inferred from the genetic distances and taxonomic varieties described for S. guianensis. The GST among the nine groups was 0.46.
Conclusions
The low HO and the GST values observed are in agreement with the outcrossing rate (26 %) estimated for this species. The data indicate a high genetic diversity among and within the botanical varieties and suggest that microsatellite-based information can be combined with classical taxonomy to elucidate infraspecific levels.
doi:10.1093/aobpla/pls001
PMCID: PMC3292737  PMID: 22479672
2.  Effects of deep brain stimulation and levodopa on postural sway in Parkinson's disease 
Objective: To quantify postural sway in subjects with Parkinson's disease and elderly controls, and determine the effects of Parkinson's disease, deep brain stimulation, levodopa, and their interactions on postural control during quiet stance.
Methods: Centre of foot pressure (CoP) displacement under each foot was measured during three 60 s trials of quiet stance with eyes open in 11 controls and six patients with Parkinson's disease. Subjects with Parkinson's disease were tested in four treatment conditions: off both deep brain stimulation and levodopa (off condition); on deep brain stimulation; on levodopa; and on both deep brain stimulation and levodopa. The variables extracted from CoP included: root mean square distance (rms), mean velocity, 95% power frequency (f95%), area of the 95% confidence ellipse (ellipse area), direction of its major axis (mdir), and postural asymmetry between the feet.
Results: rms and area of postural sway were larger than normal in subjects with Parkinson's disease in the off condition, increased further with levodopa, and significantly decreased with deep brain stimulation. Mean velocity and f95% were also larger than normal but were restored to normal by all treatments, especially by deep brain stimulation. The combined effect of deep brain stimulation and levodopa resulted in a postural sway that was an average of the effect of each treatment individually. Levodopa increased sway more in the mediolateral than in the anterior-posterior direction. Subjects with Parkinson's disease had asymmetrical mean velocity and f95% between the feet, and this asymmetry increased with levodopa but decreased with deep brain stimulation. The f95% of the CoP correlated with tremor, posture, and gait subcomponents of the unified Parkinson's disease rating scale.
Conclusions: Subjects with Parkinson's disease have abnormal postural sway in stance. Treatment with levodopa increases postural sway abnormalities, whereas treatment with deep brain stimulation improves postural sway. Quantitative evaluation of static posturography may be a useful adjunct to clinical measures in patients with Parkinson's disease.
doi:10.1136/jnnp.73.3.267
PMCID: PMC1738049  PMID: 12185157

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