In Vitro Study of Fracture Load and Fracture Pattern of Ceramic Crowns: A Finite Element and Fractography Analysis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ontogenesis, structure and ultrastructure of Hymenaea stigonocarpa (Fabaceae : Caesalpinioideae) colleters

The genus Hymenaea is characterized by a great diversity of secretory structures, but there are no reports of colleters yet. The objectives of this study are to report the occurrence and describe the origin and structure of colleters in Hymenaea stigonocarpa Mart. ex Hayne. Shoot apex samples were collected, fixed, and processed for light microscopy, scanning electron microscopy, and transmission electron microscopy as per usual methods. Colleters occur predominantly on the stipule's adaxial side. These structures are found at the base on a narrow strip, corresponding to the median vein up to half the length of the stipule. When present on the abaxial side, they are concentrated at the base and restricted to the margins. Colleters develop from the protoderm; they are elongate and club-shaped. Their body has no stratification; their surface cells differ from the inner cells only in position and presence of cuticle. Colleter cells have thin walls, dense cytoplasm, large nuclei, many mitochondria, rough endoplasmic reticulum, and abundant dictyosomes. Histochemical tests with Ruthenium red showed pectic compounds in the cytosol. In H. stigonocarpa, colleter arrangement is compatible with the hypothesis that they protect shoot apex. In this species, protection is reinforced by the sheath formed by the stipule pairs.

Paracoccidioides brasiliensis: phylogenetic and ecological aspects

The knowledge on the biological aspects of Paracoccidioides brasiliensis has evolved greatly since the first description of the disease in 1908. From the pioneers, who were able to clearly demonstrate the fungal nature of the agent, to the recent genomic era, important advances have been achieved. P. brasiliensis is a true fungus, belonging to the Ascomycetous Division, although its sexual phase has not been demonstrated morphologically. A better understanding of the fundamental aspects of the agent, especially its phylogeny and evolutionary history, will provide us with valuable insights allowing a better comprehension of the disease and our capacity to deal with the problem. Concerning the fungus's ecology, although some progress had been observed, the ecological niche of the pathogen has not been determined yet. The aim of the present review is to focus on the biological aspects of P. brasiliensis from an evolutionary point of view, addressing the fungus's phylogenetic aspects, in those special points that might be relevant for the pathogen/host interactions, the biological forces that have been acting on its origin and maintenance of virulence, as well as in determining the fungus's ecology and epidemiology.

Heterochromatin, Sex Chromosomes and rRNA Gene Clusters in Coprophanaeus Beetles (Coleoptera, Scarabaeidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Repetitive DNA probe linked to sex chromosomes in hybrids between Neotropical fish Leporinus macrocephalus and Leporinus elongatus (Characiformes, Anostomidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chromosomal painting and ZW sex chromosomes differentiation in Characidium (Characiformes, Crenuchidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The chromosomes and the sex determining mechanism of Scaphura nigra (Orthoptera, Ensifera, Tettigoniidae, Phaneropterinae).

Scaphum nigra has a uniquechromosomecomplement among approximately 100 species studied so far belonging to the subfamily Phaneropterinae. It is formed by 2n ([male]) = 26 and a FN = 29 and derived from the ancestral karyotype of the group 2n ([male]) = 31, FN = 31, by means of two centric fusions and one tandem fusion. The first between the X chromosome and a medium-sized autosome giving rise to a neo-XY sex chromosome mechanism of recent origin, and the second between two acrocentric ones, the bigger and a medium size, that gave rise to a large submetacentric element whose length is very uncommon in the subfamily. This process has created a bimodal karyotype that contrasts with the majority in this group, whose chromosomes usually can be arranged in a decreasing order of size. A third rearrangement incorporating the chromatin of a medium-sized autosome to the bigger one, explains the reduction observed in the number of chromosomes and the enlarged size of the submetacentric elements. These features demonstrate the effectiveness of chromosome number, their morphology and the change of the sex mechanism as useful tools for taxonomy.

Molecular insights on the evolution of the lateral and head lantern luciferases and bioluminescence colors in Mastinocerini railroad-worms (Coleoptera: Phengodidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cryptic sexual populations account for genetic diversity and ecological success in a widely distributed, asexual fungus-growing ant

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Species composition and plant use in old urban homegardens in Rio Claro, Southeast of Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Acerola: importance, culture conditions, production and biochemical aspects

Origin and importance. Acerola, or Malpighia emarginata D. C., is native to the Caribbean islands, Central America and the Amazonian region. More recently, it has been introduced in subtropical areas (Asia, India and South America). The vitamin C produced by acerola is better absorbed by the human organism than synthetic ascorbic acid. Exportation of acerola crops is a potential alternative source of income in agricultural businesses. In Brazil, the commercial farming of acerola is quite recent. Climatic conditions. Acerola is a rustic plant. It can resist temperatures close to 0 degrees C, but it is well adapted to temperatures around 26 degrees C with rainfall between (1200 and 1600) mm per year. Fruit characteristics. Acerola fruit is drupaceous, whose form can vary from round to conic. When ripe, it can be red, purple or yellow. The fruit weight varies between (3 and 16) g. Maturation. Acerola fruit presents fast metabolic activity and its maturation occurs rapidly. When commercialised in ambient conditions, it requires fast transportation or the use of refrigerated containers to retard its respiration and metabolism partially. Production and productivity. Flowering and fruiting are typically in cycles associated with rain. Usually, they take place in 25-day cycles, up to 8 times per year. The plant can be propagated by cuttings, grafting or seedlings. Harvest. Fruits produced for markets needs to be harvested at its optimal maturation stage. For distant markets, they need to be packed in boxes and piled up in low layers; transportation should be done in refrigerated trucks in relatively high humid conditions. Biochemical constituents. Acerola is the most important natural source of vitamin C [(1000 to 4500) mg.100(-1) g of pulp], but it is also rich in pectin and pectolytic enzymes, carotenoids, plant fibre, vitamin B, thiamin, riboflavin, niacin, proteins and mineral salts. It has also shown active anti-fungal properties. Products and market. Acerola is used in the production of juice, soft drinks, gums and liqueurs. The USA and Europe are great potential markets. In Europe, acerola extracts are used to enrich pear or apple juices. In the USA, they are used in the pharmaceutical industry. Conclusions. The demand for acerola has increased significantly in recent years because of the relevance of vitamin C in human health, coupled with the use of ascorbic acid as an antioxidant in food and feed. Acerola fruit contains other significant components, which are likely to lead to a further increase in its production and trade all over the world.

Analysis of NOR distribution in cultivated and naturalized stocks of rainbow trout (Oncorhynchus mykiss)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Intraspecific evolution of Rhizoctonia solani AG-1 IA associated with soybean and rice in Brazil based on polymorphisms at the ITS-5.8S rDNA operon

Rhizoctonia solani AG-1 IA causes leaf blight on soybean and rice. Despite the fact that R. solani AG-1 IA is a major pathogen affecting soybean and rice in Brazil and elsewhere in the world, little information is available on its genetic diversity and evolution. This study was an attempt to reveal the origin, and the patterns of movement and amplification of epidemiologically significant genotypes of R. solani AG-1 IA from soybean and rice in Brazil. For inferring intraspecific evolution of R. solani AG-1 IA sampled from soybean and rice, networks of ITS-5.8S rDNA sequencing haplotypes were built using the statistical parsimony algorithm from Clement et al. (2000) Molecular Ecology 9: 1657-1660. Higher haplotype diversity (Nei M 1987, Molecular Evolutionary Genetics Columbia University Press, New york: 512p.) was observed for the Brazilian soybean sample of R. solani AG-1 IA (0.827) in comparison with the rest of the world sample (0.431). Within the south-central American clade (3-2), four haplotypes of R. solani AG-1 IA from Mato Grosso, one from Tocantins, one from Maranhao, and one from Cuba occupied the tips of the network, indicating recent origin. The putative ancestral haplotypes had probably originated either from Mato Grosso or Maranhao States. While 16 distinct haplotypes were found in a sample of 32 soybean isolates of the pathogen, the entire rice sample (n=20) was represented by a single haplotype (haplotype 5), with a worldwide distribution. The results from nested-cladistic analysis indicated restricted gene flow with isolation by distance (or restricted dispersal by distance in nonsexual species) for the south-central American clade (3-2), mainly composed by soybean haplotypes.

Effects of powder preparation and sintering procedure on microstructure and dielectric properties of PLZT ceramics

PLZT ceramics belong to one of the very important groups of functional materials that make a basis for the production of a large range of electronic devices. The microstructure and properties of ceramics depend on the powder preparation and thermal processing conditions. Various techniques have been used to obtain chemically homogeneous and fine starting powders. PLZT powders have been prepared by two different production routes: by a modified Pechini method, using a polymeric precursor method (PMM) and by a partial oxalate method. A two-step sintering process, including a hot pressing, was carried out at 1100 and 1200degreesC Distinct phases obtained during the sintering process have been investigated by SEM and EDS techniques and dielectric properties such as permittivity and dielectric loss were measured in a frequency range from 1 to 20 kHz.. A significant difference in microstructure and dielectric properties, depending on powder origin and sintering procedure, has been noticed.

Host specificity of Metriona elatior, a potential biological control agent of tropical soda apple, Solanum viarum, in the USA

The leaf beetle Metriona elatior from Brazil-Argentina was screened in the Florida (USA) State quarantine facility as a potential biological control agent of tropical soda apple, Solanum viarum, a recently arrived weed species. Multiple-choice host-specificity tests were conducted in small cages (60 cm x 60 cm x 60 cm) using 95 plant species in 29 families. Adults fed heavily on the main target weed (S. viarum), and on turkeyberry, Solanum torvum (noxious weed of Asiatic origin); fed moderately on red soda apple, Solanum capsicoides (weed of South American origin), and eggplant, Solanum melongena (economic crop); and fed lightly on aquatic soda apple, Solanum tampicense (weed of Mexican-Caribbean-Central American origin), and on silverleaf nightshade, Solanum elaeagnifolium (native weed widely distributed). M. elatior adults laid 84 to 97% of their egg masses on S. viarum, and 3 to 16% on S. melongena. Non-choice host-specificity tests were also conducted in quarantine in which M. elatior adults and neonate larvae were exposed to 17 and 19 plant species, respectively. Tests with the neonates indicate that this insect was able to complete its development on S. viarum, S. torvum, S. melongena, and S. capsicoides. Although some adult feeding and oviposition occurred on S. melongena in quarantine on potted plants in small cages, no feeding or oviposition by M. elatior was observed in field experiments conducted in Brazil. Surveys in unsprayed S. melongena fields in Argentina and Brazil indicated that M. elatior is not a pest of S. melongena in South America. The evidence obtained from the South-American field surveys, Brazil open-field experiments, and Florida quarantine host specificity tests indicate that M. elatior causes significant feeding damage to S. viarum, and does not represent a threat to S. melongena crops in the USA. Therefore an application for permission to release M. elatior against S. viarum in the USA was submitted in October 1998.