Diversidade e estrutura genética de populações de Varronia curassavica Jacq. em restingas da Ilha de Santa Catarina / Genetic diversity and structure of Varronia curassavica Jacq. populations in the restinga of Santa Catarina Island

RESUMO Varronia curassavica Jacq. (Boraginaceae) está presente na vegetação de restinga e apresenta relevantes propriedades medicinais. A espécie é explorada especialmente por comunidades locais e pela indústria farmacêutica, porém, carece de informações ecológicas e genéticas a seu respeito. Nesse contexto, o estudo foi conduzido com o objetivo de caracterizar a diversidade genética de três populações de V. curassavica em áreas de restinga na Ilha de Santa Catarina. Foram coletadas folhas de 50 indivíduos adultos em cada uma das três áreas de estudo e as frequências alélicas das populações foram obtidas a partir de 14 locos alozímicos. Foram encontrados 25 alelos distintos nas três populações, sendo dois alelos exclusivos. As populações apresentaram diversidade genética média de 0,111 e índice de fixação médio de -0,060 (-0,273 até 0,222). Os níveis de diversidade são intermediários, semelhantes aos exibidos por espécies da mesma família ou de características ecológicas semelhantes. Os índices de fixação foram todos significativos e discrepantes entre as populações, sendo que duas delas apresentaram excesso de heterozigotos. A divergência genética interpopulacional foi significativa e igual a 0,079, considerada moderada e sugerindo efeitos de subdivisão populacional. Os níveis de diversidade genética encontrados e a redução populacional causada pela redução e fragmentação dos habitats em que a espécie ocorre sugerem medidas de conservação ex situ e demandam maior rigor na proteção legal de áreas de proteção permanente.

ABSTRACT The Varronia curassavica Jacq. (Boraginaceae) is present in restinga vegetation and shows relevant medicinal properties. The species is exploited by local communities and by the pharmaceutical industry; however, it lacks ecological and genetic information. Thus, this study aimed to characterize the genetic diversity of three V. curassavica populations in restinga areas of Santa Catarina Island. Leaves of 50 adult individuals were sampled in each of the three study areas and the allelic frequencies were obtained from 14 allozyme loci. Twenty-five different alleles were found in the three populations, two of them being exclusive. The populations showed, on average, a genetic diversity of 0,111 and a fixation index of -0,060 (-0,273 to 0,222). The diversity levels are intermediary, similar to those ones owned by species of the same family or with similar ecological traits. The fixation indexes were all significant and discrepant among the populations, with two of them showing excess of heterozygotes. The genetic divergence among populations was significant and equal to 0,079, which is considered moderate and suggests effects of population subdivision. The levels of genetic diversity found and the population decrease caused by reduction and fragmentation of habitats in which the species are present implies in ex situ conservation measures and a higher enforcement of the legal preservation of permanent protected areas.

Hypophosphatemia and phosphorus depletion in respiratory and peripheral muscles of patients with respiratory failure due to COPD.

In 22 patients (19 men, 3 women; mean [+/- SD] age, 63 +/- 6 years) with chronic obstructive pulmonary disease (COPD), phosphorus content was measured by spectrophotometric methods on muscle fragments of both peripheral (quadriceps femoris needle biopsy in 22 patients) and respiratory muscles (external intercostal muscle surgical biopsy in 14 patients). Thirty age- and sex-matched subjects were used as controls (19 for quadriceps femoris muscle biopsy and 11 for intercostal muscle biopsy). Serum phosphorus levels, as well as the main determinants of overall phosphorus metabolism (dietary intake of phosphorus and renal phosphate handling), were also obtained in all patients and control subjects. Muscle phosphorus content of both respiratory and peripheral muscles was significantly reduced in the COPD patient group, no matter what reference index was used (fat-free dry muscle weight or muscle fragment DNA content); muscle phosphorus depletion was present in about 50 percent of patients with COPD. In the same patient group, a significant relationship between muscle and serum phosphorus levels was demonstrable in the case of peripheral muscles only. No relationship was found between phosphorus content of both types of skeletal muscles and dietary phosphorus intake levels or with nutritional status, even though patients with COPD had significantly reduced anthropometric, biochemical, and immunologic indices as compared with controls. Renal phosphorus handling indices of the COPD patient group were compatible with a condition of inadequacy of the renal compensatory mechanism to hypophosphatemia and phosphorus depletion (low percent tubular reabsorption of phosphorus, low renal threshold concentration values). Our study suggests that phosphorus depletion occurs frequently in COPD, but in this clinical condition serum phosphorus levels are not representative of cellular phosphorus levels. Phosphorus depletion, which is equally severe in respiratory and peripheral muscles, could depend, at least in part, on malnutrition and a condition of renal phosphorus wasting possibly linked to some drugs commonly used in patients with COPD (xanthine derivatives, diuretics, etc).