Características morfológicas do miocárdio ventricular de Tambaqui (Colossoma macropomun; Characidae, Cuvier, 1818)

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

Chromosomal polymorphism in 12 populations of Mikania micrantha (Compositae)

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

ORGANOCHLORINE PESTICIDE-RESIDUES IN HUMAN-MILK IN THE RIBEIRAO-PRETO REGION, STATE OF SAO-PAULO, BRAZIL

Thirty-seven samples of human milk (colostrum) from donors living in the Ribeirao Preto region were analyzed to determine the levels of organochlorine pesticide residues. Donors were classified into two groups, i.e., occupationally exposed and non-exposed to pesticides. Other factors such as age, previous lactations, race, smoking habit, occupation, family income and educational level were also considered. Analysis was performed by preliminary lipid extraction followed by fractional partition on a column and finally by gas chromatography with an electron capture detector. Lindane was found in 32% of the samples in amounts of less than 0.001 mg/kg; heptachlor was found in 65% of the samples at mean levels of 0.001 mg/kg, i.e., a level five-fold lower than that established by FAO/WHO (1970) for cow's milk. Aldrin and endrin were not detected in any of the samples. Dieldrin was detected in only one sample at a level of 0.038 mg/kg, which is considered high. DDT and DDE amounts are reported as total DDT and at least one of these compounds was present in every sample. Amounts detected in donors occupationally exposed to pesticides ranged from 0.008 to 0.455 mg/kg (mean, 0.149 mg/kg), i.e., three times the limit established by FAO/WHO (1970), while values for donors who had not been exposed ranged from 0.002 to 0.072 mg/kg (mean, 0.025 mg/kg), i.e., half the limit. Considering the level of acceptable daily intake proposed by FAO/WHO (1973), lactents ingested 1% of the acceptable intake of lindane (all donors), 30% of the acceptable intake of heptachlor (all donors), 60% of the acceptable intake of DDT (non-exposed donors), and 3.7 times the acceptable intake of DDT (exposed donors). Comparing the present results with those obtained 10 years ago, the total DDT level in human milk is decreasing in this part of the country. The mean amount of organochlorine residues in non-exposed women's milk was one of the lowest levels among those recorded in the literature. DDT levels of occupationally exposed women's milk were comparable with those reported for developed countries and lower than those detected in Latin American countries. When the results of this survey are considered in relation to the advantages of breast-feeding, the risk-benefit balance is still favorable to breast-feeding. However, given the lack of long-term epidemiological studies, undesirable or harmful long-lasting effects cannot be excluded.

Interactions between genetic predisposition and environmental toxicants for development of lung cancer

Significant interindividual variations in health outcome may be caused by the inheritance of variant polymorphic genes, such as CYP2D6 and CYP2E1 for activation, and GSTM1 and GSTT1 for detoxification of chemicals. However. mechanistic studies linking the inheritance of predisposing genes with genotoxic effects towards cancer have yet to be systematically conducted. We have studied 54 lung cancer patients and 50 matched normal controls, who have been cigarette smokers, to elucidate the role of polymorphic genes in cancer. Our data indicates that the inheritance of unfavorable CYP2D6, CYP2E1, and GSTT1 genes is strongly correlated with the smoking-related lung cancer. For heavy cigarette smokers (> 30 pack-years), the smoking habit is the strongest predictor of lung cancer risk irrespective of the inheritance of unfavorable metabolizing genes. For moderate to light smokers (< 30 pack-years), the genetic predisposition plays on important role For the risk (odds ratio = 3.46; 95% CL = 0.46-40.2). Using a subgroup of the study population, we observed that cigarette smokers having the defective GST genes have significantly more chromosome aberrations as determined by the fluorescence-in-situ-hybridization (FISH) technique than smokers with the normal GST genes (P < 0.001). In conclusion, our study provides data to indicate that individuals who have inherited unfavorable metabolizing genes have increased body burden of toxicants to cause increased genetic damage and to have increased risk for cancer. Studies like ours can be used to understand the basis for interindividual variations in cancer outcome, to identify high risk individuals and to assess health risk. (C) 1997 Wiley Liss, Inc.

Botryoidal platinum, palladium and potarite from the Bom Sucesso stream, Minas Gerais, Brazil: Compositional zoning and origin

Platinum-Pd nuggets from the Born Sucesso stream alluvium Minas Gerais, Brazil. have been investigated by electron-probe microanalysis. The nuggets attain 1 mm in maximum dimension and have a botryoidal habit, with pronounced compositional core-to-margin zoning of internal structures, Although there is a wide variation in internal morphology and individual zones vary markedly in thickness (<1-100 mum), a typical composite arborescent nugget comprises a broad irregular core region of massive auriferous Pd-Hg alloy (potarite delta-PdHg) or cavity space + relict potarite enclosed by a narrow zone of platiniferous, palladium or alloy of near Pt50Pd50 composition, and is progressively oscillatory zoned by palladian platinum, with growth eventually enveloping the whole botryoidal colony, to a narrow rim of palladian platinum or pure platinum. Other nuggets comprise an arborescent to dendritic core of auriferous potarite, a broad internal zone of either pure platinum or palladian platinum, and a narrow rim of platinum, the mineral palladium contains up to about 65 at.% Pd; this is the first detailed modern confirmation of palladium in its type locality. Auriferous potarite ranges in composition from similar toPd(3)Hg(2) to near Pd(Hg,Au). The origin of these nuggets remains unclear, but their mineralogy is broadly equivalent to that of palladian gold. potarite and platinum in alluvial sediments and overburden from Devon, England, which are considered to be detrital, and their platinum-group-clement geochemistry is consistent with precipitation from hydrothermal fluids. We suggest that the Bom Sucesso nuggets resulted from high-level episodic hydrothermal alteration of mafic and ultramafic rocks within the drainage basin, with the remobilized Pt and Pd precipitated in open spaces in the enclosing metaquartzites.

Variations in tree community composition and structure in a fragment of tropical semideciduous forest in southeastern Brazil related to different human disturbance histories

In an area of tropical seasonal semideciduous forest, the soil characteristics, floristic composition, physiognomic structure, and the distribution of three regeneration and three dispersal guilds were studied for four stands within the forest that had documented histories of varying degrees of human disturbance. The aim was to study forest regeneration in areas of preserved forest and secondary forest, with parts of both types of forest experiencing either 'intensive' or 'occasional' cattle trampling. The study was carried out in the Sebastiao Aleixo da Silva Ecological Station, Bauru, São Paulo State, Brazil. Two stands were called 'secondary' because they corresponded to forest tracts that were felled and occupied by crops and pastures in the past and then abandoned to forest regeneration ca. 40 years before this study. The other two stands, called 'preserved', corresponded to areas of the fragment where the forest has been maintained with only minor human impacts. The arboreal component of the tree community (diameter at breast height or dbh greater than or equal to 5 cm) was sampled in 20 plots of 40 m x 40 m, and the subarboreal component (diameter at the base of the stem or dbs < 5 cm and height greater than or equal to 0.5 m) in subplots of 40 m x 2 m. Physiognomic features, such as canopy height and density of climbing plants, were registered all over a 5 m x 5 m gridline laid on the sample plots. Soil bulk samples were collected for chemical and textural analyses. Most detected differences contrasted the secondary to the preserved forest stands. The soils of the secondary stands showed higher proportions of sand and lower levels of mineral nutrients and organic matter than those of the preserved stands, probably due to higher losses by leaching and erosion. Compared to the secondary stands, the preserved ones had higher proportions of tall trees, higher mean canopy height, lower species diversity, higher abundance of autochorous and shade-tolerant climax species, and lower abundance of pioneer and light-demanding climax species. Despite the high proportion of species shared by the preserved and secondary stands (108 out of 139), they differed consistently in terms of density of the most abundant species. on the other hand, the secondary and preserved stands held similar values for tree density and basal area, suggesting that 40 years were enough to restore these features. Effects of cattle trampling on the vegetation were detected for the frequency of trees of anemochorous and zoochorous species, which were higher in the stands under occasional and intensive cattle trampling, respectively. The density of thin climbers was lower in the stands with intensive trampling. (C) 2004 Elsevier B.V. All rights reserved.

SOCIAL-CONTROL OF GROWTH IN FISH

This review concerns the phenomenon of heterogeneous growth (Het-G) in fish. Het-G is characterized by different growth rates between conspecifics. Although genetic determination on Het-G is recognized, grouping increases the difference in size between conspecifics. This review focuses on population factors and the mechanisms underlying the socially mediated Het-G are summarized and discussed. The aim of this paper is to arrive at a general statement explaining why grouping decreases mean growth and why it suppresses growth only in some individuals. The mechanisms described are: a) food competition, b) chemical factors released by conspecifics, and c) social stress. Social stress is analyzed in terms of the effect on appetite, digestive processes and metabolism. It is proposed that the predominant mechanism promoting socially mediated growth suppression is related to the social habit of the species. The biological significance of growth heterogeneity in fish is also discussed. Growth variability is suggested as an adaptative strategy to optimize survival of the population in a restricted space.

The use of extruded feed in fish food

In our country, the intensive culture of fish has been making progress due to the availability of extruded rations, which are characterized by the way they have been formulated to assist the nutritional demands of the tropical species and for facilitating a better practice of alimentary handling. This process checks the extruded product density and the desirable physical/chemical aspects to a diet that should be handled in the water, the critical factor of this activity. It is important to emphasize that this product stays to the surface of the water, facilitates the consumption control and the observation of the general aspects of the school of fish, as well as guaranteeing that no deterioration of the physical/chemical characteristics of the water occurs. The floating characteristic of the extruded ration is preferable for farmers because most of the tropical species feed at the surface of the water. In some cases, in the function of the alimentary habit, the thermal conditions of the water and the handling system produce granules with different densities. This is due to the humidity and the applied cooking heat, which modifies the time of hydration, and consequently the ability to float. To establish the physical presentation idea for a ration for tropical fishes, it is necessary that the pellets come in sizes, textures, humidities and densities in order to allow for the different phases of the lives of the fishes. This ration should be the result of characteristics of the species, such as the anatomophysiologics particularities, alimentary habits, digestive capacity and alimentary behavior. Only in this way is it possible to offer to those fishes a ration whose nutritious value and physical presentation facilitate the best biological and economic answers.Those aspects need to be reviewed because the tropical species that are cultivated in our country present selective behavior in relation to the size of the pellet. Generally, this has access to the digestive system without waste; the digestibility, therefore, is dependent upon the size of the particles and the physical aspects of the pellets. They should still consider that those granules could be less abrasive and softer. The extruded rations available in the national market present a qualitative reference to its proteic level, whose consequence allows us to infer that those are overestimated for the final phase of those fishes. Thus, the final cost of production is made unfeasible. In this point of view of the development of the national fish culture, and the growing adoption of the intensive system of production, it can link that such progress is a function of the availability of the rations in the extruded form. Although this technique of processing of rations has revolutionized the market in such a way that has been seen as preferable for farmers, some feel that there is a lack of products best suited for the initial phases of fingerlings production.

Ocorrência e flutuação populacional de ácaros associados a seringais vizinhos de fragmentos de cerrado

The basic knowledge of the seasonal occurrence of mites can supply data for elaboration of programs of ecological management to be implanted with success in the future. The objective of this study was to determine the species richness and the seasonality of mites present in two areas of rubber tree crops neighboring to native areas in Itiquira, MT. Along one year, 25 quantitative samplings were accomplished in rubber tree crop neighboring to two fragments of Cerrado (Cerradao and Mata Riparia). There were registered 199,380 mites, of 48 species, belonging to 15 families. of those, 13 species are phytophagous, 18 predators and 17 mycophagous or of unknown alimentary habit. Three phytophagous species represented more than 97% of the mites collected: Phyllocoptruta seringueirae Feres (80.8%), Tenuipalpus heveae Baker (12.7%) and Calacarus heveae Feres (3.6%). Among the predators, the most abundant species were Agistemus sp., Scirula sp. and Euseius concordis (Chant). Twenty-eight species were common to both crops. The families that had the largest number of species collected in the neighboring area to Cerradao were Tydeidae (7), Tarsonemidae (6), Eriophyidae and Phytoseiidae (4), and in the area close to Mata Riparia, Tydeidae (9) and Phytoseiidae (8). The presence of vegetation near the crop should explain the great number of species of mites classified as accidental found in this study. The largest abundances and species richness occurred in the end of the rainy season and beginning of the dry season.

POTASSIUM FERTILIZATION, ROOT MORPHOLOGY AND POTASSIUM ABSORPTION BY SOYBEAN

A greenhouse experiment studied the effect of potassium fertilization on soybean (Glycine max L. Merrill) root morphology and on K absorption by six soybean cultivars of different maturation groups and growth habits. The Plants were grown up to 70 days after plant emergence, in pots containing 6.0 kg of soil. In the absence of K, no significant difference in K absorption was observed among the cultivars or in root length and surface, but root mean radius was correlated to K absorption. Differences in K absorption were not associated with root characteristics in the presence of K fertilization. Physiological adjustments in K uptake, as well as K availability in the soil, were more important in soybean nutrition than were morphological adjustments in the root system. The results were not associated with plant growth habit or with maturation group.

Three new South American species of Salacia with fasciculate inflorescences (Celastraceae, Hippocrateoideae)

Three new fasciculate flowered species of Salacia L. (Celastraceae, Hippocrateoideae) from the Amazon basin are described: S. acevedoi Lombardi is distinguished by its small flowers, stamens with short filaments, disc connate to ovary, and size of fruits; S. negrensis Lombardi differs by its habit, characteristics and shape of leaves, flower diameter, features and size of stamens, and number of ovules: and S. odorata Lombardi is characterized by its long pedicels, conical flower buds, strongly adherent petals. and flat disc with fimbriate outer border.

The relationship between diet quality and basal metabolic rate in endotherms: Insights from intraspecific analysis

In this article, we review intraspecific studies of basal metabolic rate (BMR) that address the correlation between diet quality and BMR. The food-habit hypothesis stands as one of the most striking and often-mentioned interspecific patterns to emerge from studies of endothermic energetics. Our main emphasis is the explicit empirical comparison of predictions derived from interspecific studies with data gathered from within-species studies in order to explore the mechanisms and functional significance of the putative adaptive responses encapsulated by the food-habit hypothesis. We suggest that, in addition to concentrating on the relationship among diet quality, internal morphology, and BMR, new studies should also attempt to unravel alternative mechanisms that shape the interaction between diet and BMR, such as enzymatic plasticity, and the use of energy-saving mechanisms, such as torpor. Another avenue for future study is the measurement of the effects of diet quality on other components of the energy budget, such as maximum thermogenic and sustainable metabolic rates. It is possible that the effects of diet quality operate on such components rather than directly on BMR, which might then push or pull along changes in these traits. Results from intraspecific studies suggest that the factors responsible for the association between diet and BMR at an ecological timescale might not be the same as those that promoted the evolution of this correlation. Further analyses should consider how much of a role the proximate and ultimate processes have played in the evolution of BMR.

Geophagy in the golden-faced saki monkey (Pithecia pithecia chrysocephala) in the Central Amazon

The golden-faced saki monkey Pithecia pithecia chrysocephala (Cebidae, Primates) was observed eating soil from termite nests during a long-term study of a family group in a Central Amazonian forest fragment. In this paper we describe the behaviour involved in the geophagy in these monkeys, and the results of geochemical and physical analyses of the termite nest material, as well as root mat and topsoil samples below the trees, in order to clarify the possible reasons for it. The sakis ate soil from nine arboreal termite nests on 26 soil feeding-bouts (in 853 observation hours); 25 soil feeding-bouts occurred in March 1987 (rainy season), during 19 days or 132 observation hours, and occupied 0.7% of the feeding time. Geophagy frequencies did not differ between sexes (17 feeding-bouts of four females and 8 for two males). Mineral composition was higher in arboreal termitaria than in the topsoil. Kaolinite was the major clay component. Tannin adsorptive capacity, tested through a modified radial diffusion method of Hagerman, was around 10-20%, similar to a control with kaolin (10-20%), but lower than bentonite or celite (30-45%). The observations reported here, although inconclusive as to the function of geophagy in this species, indicate that it is not a mineral supplement during times of scarcity or high consumption of leaves, as has been reported for other primates, nor that it is related to fruit consumption (redressing possible mineral imbalance), as has been suggested for some other frugivorous mammals. Our results do not rule out tannin adsorptive hypothesis for the ingestion of clays, but, being an irregular habit, we argue that it is most likely related to rare and occasional dietary components.

Epibiosis and molting in two species of Callinectes (Decapoda: Portunidae) from Brazil

The external infestation of Callinectes ornatus Ordway, 1863 and Callinectes danae Smith, 1869, in particular cirripeds, was studied for two consecutive years in the Ubatuba Bay (SP) (23 degrees 26' S and 45 degrees 02' W). Bryozoans, polychaetes and cirripeds were found on both swimming crab species, but cirripeds were the most abundant and frequent. The number of infested swimming crabs increased proportionally to carapace size, but not surpassing 30 %, suggesting an absence of terminal anecdysis in both species. The establishment of the pernicious organisms on their hosts is influenced by other factors, such as their habit of burying themselves in sediments. The correlation between molting activity in adult specimens of both sexes and the low incidence of epizoonts suggest that C. ornatus and C. danae may be molting after maturity.

Diferentes resposta de cutivares de soja e potássio

Soybean (Glycine max (L.) Merrill) is known to have a high ability as a potassium extractor, and different cultivars show different potassium requirements. An experiment was run to study the potassium nutrition of soybean as related to plant characteristics. Six soybean cultivars (FT-2, Bossier, IAC-11, IAC-17, IAC-18 and IAC-19) were grown in 6 kg pots filled with the topsoil of a Dark Red Latosol (sandy loam), either with and without K fertilization. The plants were harvested 70 days after emergence. Soybean response to potassium was not related to growth habit or group of maturation. There was a different response to K. The cultivars IAC-18 and FT-2 were less tolerant to K deficiency. Potassium deficiency in the leaves was not related to top dry matter production. With K fertilization soybean plants showed small root volume and higher ratio canopy/root. With high K in soil, all of the cultivars showed higher nodulation.