Genetic diversity of Casearia sylvestris populations in remnants of the Atlantic Forest.

Guaçatonga (Casearia sylvestris) is a native plant of the Atlantic Forest, with high medicinal potential and relevance for reforestation programs. The aim of this study was to characterize, with microsatellite markers, two populations of C. sylvestris from remaining areas of the Atlantic Forest in the State of São Paulo. High allelic variation was found in both populations (NA = 101 and 117; AR = 12.5 and 14.4), although with high endogamy coefficients (f = 0.640 and 0.363). Estimates of genetic structure suggested the presence of considerable genetic divergence between the populations (FST = 0.103); however, there was no spatial genetic structure within the populations. Genetic divergence may have occurred due to decreased gene flow between the fragmented populations as the result of deforestation. The results of this study demonstrate the importance of genetic diversity and its characterization in native plants within remaining forest areas for the management and restoration of such areas.

Genetic diversity among air yam (Dioscorea bulbifera) varieties based on single sequence repeat markers.

Dioscorea is the largest genus in the Dioscoreaceae family, and includes a number of economically important species including the air yam, D. bulbifera L. This study aimed to develop new single sequence repeat primers and characterize the genetic diversity of local varieties that originated in several municipalities of Brazil. We developed an enriched genomic library for D. bulbifera resulting in seven primers, six of which were polymorphic, and added four polymorphic loci developed for other Dioscorea species. This resulted in 10 polymorphic primers to evaluate 42 air yam accessions. Thirty-three alleles (bands) were found, with an average of 3.3 alleles per locus. The discrimination power ranged from 0.113 to 0.834, with an average of 0.595. Both principal coordinate and cluster analyses (using the Jaccard Index) failed to clearly separate the accessions according to their origins. However, the 13 accessions from Conceição dos Ouros, Minas Gerais State were clustered above zero on the principal coordinate 2 axis, and were also clustered into one subgroup in the cluster analysis. Accessions from Ubatuba, São Paulo State were clustered below zero on the same principal coordinate 2 axis, except for one accession, although they were scattered in several subgroups in the cluster analysis. Therefore, we found little spatial structure in the accessions, although those from Conceição dos Ouros and Ubatuba exhibited some spatial structure, and that there is a considerable level of genetic diversity in D. bulbifera maintained by traditional farmers in Brazil.

Distribution, management and diversity of the endangered Amerindian yam (Dioscorea trifida L.).

The objective of this study was to verify the occurrence of Dioscorea trifida in Brazil and to obtain information concerning its distribution, management and diversity. Farmers from 21 communities were interviewed in the states of São Paulo, Santa Catarina and Mato Grosso. During the visits, semi-structured interviews were conducted to collect socio-economic, management and diversity data for this crop. Fifty-one collected accessions, plus two accessions obtained at local markets of Amazonas, were characterized using 12 morphological traits. Most the interviewed farmers were men (75%) with a mean age of 59.5 years. Just a few young people and labor force were available for agricultural activities, with an average of only three individuals per farm. Most farmers (56%) grew only one variety of D. trifida, although 44% had more than one variety in their fields, which aims to provide greater assurance at harvest. Many popular names were observed for D. trifida, and cará roxo (purple yam) was the name most used by farmers (43.4%). Characters referring to the tuber, such as skin and flesh color, were most relevant for the distinction of the accessions. The results of this study may collaborate to develop strategies for conservation, both ex situ and in situ, within the view of on farm conservation.

A modified acidic approach for DNA extraction from plant species containing high levels of secondary metabolites.

Purified genomic DNA can be difficult to obtain from some plant species because of the presence of impurities such as polysaccharides, which are often co-extracted with DNA. In this study, we developed a fast, simple, and low-cost protocol for extracting DNA from plants containing high levels of secondary metabolites. This protocol does not require the use of volatile toxic reagents such as mercaptoethanol, chloroform, or phenol and allows the extraction of high-quality DNA from wild and cultivated tropical species.

Distribution, management and diversity of yam local varieties in Brazil: a study on Dioscorea alata L.

Widely spread in the tropics, yams were introduced into Brazil during the colonial period and are currently grown throughout the country. Despite its importance as a pharmacological and food source, there is a lack of studies describing how and where this tuber is grown in Brazil. The aim of this study was to provide an overview of the cultivation and distribution of Dioscorea alata in different Brazilian regions. A total of 63 farmers were visited in different municipalities and communities in four regions in the country: South, Southeast, Northeast and Midwest. Semi-structured interviews were conducted to collect socio-economic, use, management and diversity data for this crop. The majority of interviewers were men, married, with children, using retirement benefits and agriculture as income and family labour as the main support in the yam cultivation. A wide distribution of this species was found, with the occurrence of D. alata in the four sampled regions. A variety of vernacular names for this species was collected, differing according to the region where it is cultivated. Most farmers cultivate yams in fields, however an increased usage of home gardens for the cultivation of this tuber was found. Also, most farmers cultivate yams in association with other crops in areas of different sizes and slash and burn practices, although mostly disappearing, are still being used by many farmers. The results of this study provide more concrete data on the distribution and diversity of this important crop.

Inbreeding effects in Solanum lycocarpum A. St.-Hil populations, an endangered species of the Brazilian Cerrado.

The inbreeding effective population size is an estimate of inbreeding and genetic drift in populations. It is an important tool for conservation genetics because it represents the number of individuals that are effectively contributing alleles to the subsequent generations. Several studies have been published in the last decades on the genetic structure of natural plant populations of the Cerrado, the Central-Brazilian savannahs, but most of them do not present effective size estimates. The objective of this study was to show such estimates for Solanum lycocarpum, a Cerrado species that is in danger of genetic erosion. We utilized microsatellites, isozymes, and 2 natural populations for each marker to estimate the population inbreeding effective size of a group of populations (N(^)e(v)) and the minimum number of populations that should be conserved (S(^)(ref)) in order to retain an effective number of 500. For the 2 markers that were utilized, only approximately 12% of the individuals are effective in the populations. The value obtained for S(^)(ref) was approximately 80.

Microsatellite polymorphisms in cassava landraces from the Cerrado biome, Mato Grosso do sul, Brazil.

Using nine microsatellite loci, we investigated genetic structure and diversity in 83 Brazilian cassava accessions, including several landraces, in the Cerrado biome in Mato Grosso do Sul, Brazil. All nine loci were polymorphic, averaging 6.00 alleles per locus. Treating each of seven municipalities as a cassava group or population, they averaged 3.5 alleles per locus, with 97% polymorphic loci, high values for observed heterozygosity (0.32) and gene diversity (0.56). Total genetic variability was high (0.668), and most of this genetic variability was concentrated within municipalities (0.577). Cluster and structure analyses divided accessions into two major clusters or populations (K = 2). Also, a significant genetic versus geographic correlation was found (r = 0.4567; P < 0.0260). Migratory routes in the Cerrado are considered main contributors to the region's high cassava diversity and spatial genetic structure, amplifying interactions between traditional farmers and the evolutionary dynamics of this crop.

Toxoplasmose: ocorrência de anticorpos antitoxoplasma gondii e diagnóstico / Toxoplasmosis: occurrence of antibodies antitoxoplama gondii and diagnosis

A toxoplasmose é uma zoonose de ampla distribuiçäo geográfica, sendo uma infecçäo oportunista, principalmente em pacientes com Aids. A incidência dos anticorpos séricos, antiToxoplasma gondii, é variável, sendo crescente com os diferentes grupos etários. Os métodos laboratoriais para o diagnóstico desta doença incluem o exame da espécie patógena e os testes imunológicos. Embora os testes sorológicos tenham suas limitações, säo ainda os mais utilizados nos laboratórios de análises clínicas. Na melhoria do diagnóstico da toxoplasmose congênita e em pacientes com AIDS, tem-se empregado, alternativamente, a reaçäo em cadeia de polimerase (PCR) e Nested-PCR. OBJETIVOS: Enfocar a ocorrência de toxoplasmose, considerando-se as diferentes técnicas e formas de interpretaçäo nos exames sorológicos. MÉTODOS: No presente trabalho, avaliamos os anticorpos (Ac) antiToxoplasma gondii de 2.994 pacientes atendidos no Laboratório do Hospital Universitário (LAC-HU), da Universidade Federal de Santa Catarina, no período de 28 de fevereiro de 1996 a 28 de julho de 1998. Essa avaliaçäo foi realizada através da utilizaçäo da reaçäo de Imunofluorescência Indireta (IFI) e confirmada pelo método do ensaio imunoenzimático (ELISA). RESULTADOS: Os resultados mostraram que 41,91 por cento desses pacientes possuíam Ac antiToxoplasma gondii, sendo que 0,87 por cento possuíam IgM, em diferentes títulos, estando ou näo desenvolvendo a fase aguda da doença. Este estudo vem demonstrar que a prevalência de toxoplasmose em nosso meio é relativamente alta e que para a identificaçäo do processo agudo da doença, a rotina sorológica pode ser enriquecida de técnicas mais sensíveis e específicas, que permitam a evidenciaçäo do microrganismo, contribuindo para o melhor diagnóstico

[Toxoplasmosis: occurrence of antibodies antitoxoplasma gondii and diagnosis]. / Toxoplasmose: ocorrência de anticorpos antitoxoplasma gondii e diagnóstico.

UNLABELLED: Toxoplasmosis is a zoonosis of broad geographic distribution, being an opportunist infection mainly in AIDS patients. The incidence of serum antibodies of the type anti-Toxoplasma gondii is variable and growing according the different age groups. The laboratory test for the diagnostic of this disease, include the exam of the pathologic species as well as immunologic tests. Although the serum tests have limitations, they are still utilized in the Clinical Analysis laboratories. To improve the congenital toxoplasmosis diagnosis in AIDS patients, the polymerase chain reaction (PCR) and Nested-PCR have been utilized alternatively. PURPOSES: To focus the occurrence of toxoplasmosis, considering the different techniques and shapes of point of views in the serological analysis. METHODS: The antibodies (Ac) anti-Toxoplasma gondii of 2994 patients from the Santa Catarina Federal University Hospital, in the period from February 28, 1996 to July 28, 1998 were evaluated. This evaluation was accomplished by the Immunofluorescency Indirect reaction, which was confirmed by the ELISA method. RESULTS: The results showed that 41.91% of the patients had the antibodies anti-Toxoplasma gondii. From this total we concluded that 0.87% of these patients had the IgM in different titles which can be or not classified in the acute phase of the disease. This study demonstrates that the incidence of toxoplasmosis in our orment is relatively high. It shows too that in the identification of the acute process of the disease, the serologic tests can be added to a more sensible and specific techniques that allows the evidentiation of the microorganism thus contributing to a better diagnosis.