bluuebunny/crossref_metadata_2025 huggingface dataset:
Reproduction of species of the genus Cichla in a reservoir in Southeastern Brazil
Authors: Gomiero L. M. , Braga F. M. S.
Published: April 2005

The reproduction of two species of Cichla (Cichla cf. ocellaris and C. monoculus, commonly known in Brazil as tucunaré) introduced in the Volta Grande Reservoir, southeastern Brazil, was analyzed. The period for spawning began at the end of the dry season (September) and extended until the end of the rainy season (January). The length of the first gonad maturation (L50) and the length at which all fish are considered adults (L100) were very similar for both species and coincide with the length of fish at one year of age. The analysis of disassociated oocytes evidenced a partitioned spawning, and that C. monoculus was more prolific than C. cf. ocellaris. The low fecundity, partitioned spawning, bi-parental brood care, and supplying of food for the young are related to the way of life, habitat, and reproductive behavior of these fish.
Advertisement call of Hyla jimi and Hyla elianeae (Anura, Hylidae) in the Botucatu Region, São Paulo, Brazil
Authors: Martins I. A. , Jim J.
Published: April 2005

In this work we present a description of the advertisement call of H. jimi, the locality type, and of H. elianeae, until now unknown in the literature. Field activities were carried out from August 1997 through June 1999; recordings were made in two open-area environments in the Botucatu region, São Paulo State. Vocalizations of 100 individuals (49 H. jimi and 51 H. elianeae) were recorded; nine characteristics of the advertisement call were examined. The advertisement calls of both species consist of consecutive series of simple notes with relatively fast repetition rates. Males of H. jimi and H. elianeae presented two patterns of note emission: one emitted by individuals beginning vocalization activity or isolated from the aggregate, and another emitted by males in chorus activity interacting with closely neighboring males. A significant difference was verified in the temporal structure of the two vocalization patterns.
Changes in gut gross morphology of traíra, Hoplias malabaricus (Teleostei, Erythrinidae) during long-term starvation and after refeeding
Authors: Rios F. S. , Kalinin A. L. , Fernandes M. N. , Rantin F. T.
Published: April 2005

Adult traíra (Hoplias malabaricus) were submitted to different periods of food deprivation (from 30 to 240 days) and refed for 30 days after 90 and 240 days of starvation. Stomach length remained constant during all the experimental period. However, the intestine length was significantly reduced after 30 days of food deprivation. Normal length was not recovered after refeeding. The number of pyloric caeca did not change significantly. Conversely, caeca thickness decreased after 150 days of starvation and their length decreased after 180 days. After refeeding, however, the pyloric caeca recovered original thickness. In fish refed after 240 days of starvation the length of these structures seemed to present compensatory growth, becoming longer than in the control group.
Effects of irradiance on non-structural carbohydrates, growth, and hypoglycemic activity of Rhynchelytrum repens (Willd.) C.E. Hubb. (Poaceae)
Authors: Souza A. , De Paula A. C. C. F. F. , Figueiredo-Ribeiro R. C. L.
Published: April 2005

Irradiance is a crucial factor in plant development. Different radiant energy levels cause different responses related to plant growth and the production and distribution of dry matter. Considering the relationship between light availability and metabolism of carbohydrates and derived compounds, the aim of this work was to assess the effects of irradiance on non-structural carbohydrate contents and composition, as well as on the hypoglycemiant activity of Rhynchelytrum repens, a pantropical grass species popularly used for diabetes treatment. Plants of R. repens growing under natural irradiance (NI) showed increased content of total soluble carbohydrate (TSC), higher fluctuations in starch content (SC) and higher number of tillers. The flowering process of these plants was preceded by an increase in sucrose. However, their water content was low when compared to that of plants cultivated under low irradiance (LI). The ratio root/aerial organs and SC showed no significant differences in plants grown under LI, although TSC increased and a lower number of tillers were observed during the experimental period. In both conditions, sucrose was the ubiquitous sugar and seemed to be involved in the flowering process. A reduction in the blood sugar level was observed through the intra-peritoneal (IP) administration of the precipitate of aqueous extracts obtained from plants growing in both conditions of light; the supernatant fraction showed no hypoglycemic effect.
Feeding of introduced species of Cichla (Perciformes, Cichlidae) in Volta Grande reservoir, River Grande (MG/SP)
Authors: Gomiero L. M. , Braga F. M. S.
Published: April 2005

Both species studied, Cichla cf. ocellaris and Cichla monoculus, fed mainly on fish, the first on Cichla spp., Plagioscion squamosissimus, and Tilapia rendalli, and the second, Cichla monoculus, on Cichla spp. Both diets indicated a strong correlation among the food items. Remarkable ontogenetic change was noted in both species diet: the young fed on crustaceans and insects while the adults fed mainly on fishes. The species studied, which are highly adapted to a brief life span, cause serious damage to the fish communities by predation, competition, and cascade effects throughout the whole trophic chain.
Flowers, fruits, and the abundance of the yellow-chevroned parakeet (Brotogeris chiriri) at a gallery forest in the South Pantanal (Brazil)
Authors: Ragusa-Netto J.
Published: April 2005

Parakeets usually forage for massive and ephemeral plant resources at forest canopies. Fruit pulp is widely cited as a major food resource for these birds, which often eat seeds and nectar. In this study, I assessed flower and fruit production at a gallery forest in the Pantanal flood plain (Brazil) in order to evaluate the relationship between food resource production and abundance of a common parakeet, Brotogeris chiriri. Also, I evaluated the relationship between food resource production and foraging activity. Parakeet abundance varied markedly along the year, coinciding with massive episodes of flower and fleshy fruit availability. Inga vera nectar, intensely used during the latter part of dry season, was by far the most exploited food item by parakeets when they were very abundant. The nectar comprised 34% of the parakeets' diet (N = 131 feeding records) at the gallery forest, while fleshy fruits made up the rest. Parakeets principally exploited fruits of Cecropia pachystachya and Ficus luschnathiana, besides palm fruits and Inga vera arils. The consistent relationship between foraging activity and parakeet abundance, as well as the coincidence between fluctuations of these parameters and availability of major food resources, suggests that food availability mostly influenced B. chiriri occurrence in the gallery forest. Furthermore, I found no evidence for gallery forest use for roosting and/or breeding, in spite of the fact that such factors usually influence local parakeet abundance.
Relative efficiency of anuran sampling methods in a restinga habitat (Jurubatiba, Rio de Janeiro, Brazil)
Authors: Rocha C. F. D. , Van Sluys M. , Hatano F. H. , Boquimpani-Freitas L. , Marra R. V. , Marques R. V.
Published: April 2005

Studies on anurans in restinga habitats are few and, as a result, there is little information on which methods are more efficient for sampling them in this environment. Ten methods are usually used for sampling anuran communities in tropical and sub-tropical areas. In this study we evaluate which methods are more appropriate for this purpose in the restinga environment of Parque Nacional da Restinga de Jurubatiba. We analyzed six methods among those usually used for anuran samplings. For each method, we recorded the total amount of time spent (in min.), the number of researchers involved, and the number of species captured. We calculated a capture efficiency index (time necessary for a researcher to capture an individual frog) in order to make comparable the data obtained. Of the methods analyzed, the species inventory (9.7 min/searcher /ind.- MSI; richness = 6; abundance = 23) and the breeding site survey (9.5 MSI; richness = 4; abundance = 22) were the most efficient. The visual encounter inventory (45.0 MSI) and patch sampling (65.0 MSI) methods were of comparatively lower efficiency restinga, whereas the plot sampling and the pit-fall traps with drift-fence methods resulted in no frog capture. We conclude that there is a considerable difference in efficiency of methods used in the restinga environment and that the complete species inventory method is highly efficient for sampling frogs in the restinga studied and may be so in other restinga environments. Methods that are usually efficient in forested areas seem to be of little value in open restinga habitats.
Embryonic development time of Penilia avirostris Dana, 1852 in a tropical bay in Brazil
Authors: Valentin J. L. , Marazzo A.
Published: April 2005

Development time of embryos in the brood pouch of the cladoceran Penilia avirostris Dana, 1852, was estimated by collecting zooplankton daily for 15 days in surface water of Guanabara Bay, Brazil. Each day the maturity stage of embryos of 90 parthenogenic females was noted. Total development time (egg to birth) varied from 2 to 3 days, the immature phase (stages I to IV) being generally longer (2 days) than intermediate and mature phases (1 day, stages V to XII). Similar results were obtained from Bottrell's equation, which takes water temperature into account.
Positive, negative and marker-free strategies for transgenic plant selection
Authors: Aragão Francisco José Lima , Brasileiro Ana Cristina Miranda
Published: April 2005

In this review, the use of the most common selection marker genes on plant transformation and the effects of their respective selective agents are discussed. These genes could be divided in two categories according their mode of action: genes for positive and negative selection. The retention of the marker gene flow through chloroplast transformation is also discussed. Further, strategies to recover marker-free transgenic plants, involving multi-auto-transformation (MAT), co-transformation, site-specific recombination and intragenomic relocation of transgenes through transposable elements are reviewed.
Caracterização de ER49, um fator de elongação da síntese de proteínas do tipo Ts, expresso durante a maturação do fruto de tomate
Authors: Chaves Ana Lúcia S. , Silva J.A. , Pech J.-C. , Latche A. , Bouzayen M. , Zegzouti H. , Rombaldi Cesar V.
Published: April 2005

O etileno, conhecido, sobretudo, como o fitormônio da maturação de frutos, está envolvido em vários processos fisiológicos, atuando na regulação da expressão de grande número de genes. O clone parcial de cDNA ER49 foi previamente isolado mediante a técnica do "Differential Display". A obtenção e a análise da seqüência completa confirmaram as homologias significativas com fatores de elongação da síntese de proteínas do tipo Ts. Tais proteínas são responsáveis pela reciclagem do complexo EF-Tu•GDP, que atua na ligação do aminoacil-RNAt ao ribossomo. A predição da seqüência protéica permitiu a detecção de um peptídio sinal de endereçamento para a mitocôndria e dos domínios TS-N e EF-Ts. A modelagem da estrutura terciária mostrou que ER49 poderia interagir com EF-Tu•GDP, para promover a reciclagem de GDP em GTP. Estudos de expressão durante a maturação do fruto de tomate (Lycopersicon esculentum Mill.), var. Micro-Tom, foram realizados por RT-PCR, revelando que ER49 tem sua expressão induzida nos últimos estádios de maturação do fruto. Os resultados da análise do DNA genômico por Southern blot sugerem que ER49 faz parte de uma família multigênica de 2-3 elementos. Através de ER49, gene mitocondrial regulado pelo etileno, surgem novas perspectivas para o estudo da regulação de genes em nível pós-transcricional e de sua relação com o metabolismo respiratório.
Efeito da aplicação de zinco via foliar na síntese de triptofano, aminoácidos e proteínas solúveis em mudas de cafeeiro
Authors: Malta Marcelo Ribeiro , Furtini Neto Antônio Eduardo , Alves José Donizeti , Guimarães Paulo Tácito Gontijo
Published: April 2005

Avaliou-se, neste trabalho, o efeito da aplicação de Zn via foliar na síntese de triptofano, aminoácidos totais e proteínas solúveis totais em mudas de cafeeiro (Coffea arabica L.). Cultivaram-se as mudas em solução nutritiva sem Zn durante quatro meses e após esse período, pulverizaram-se as plantas com ZnSO4.7H2O a 0,6 %, definindo-se os tratamentos segundo a posição de aplicação (basal: 6 pares de folhas inferiores, ou apical: 6 pares de folhas superiores, além dos ramos plagiotrópicos). As plantas foram coletadas nos tempos: 0 (testemunha), 12, 24, 48 ou 72 h após aplicação de Zn, separando-se as folhas da região apical, basal e dos ramos plagiotrópicos. Determinaram-se as concentrações foliares de triptofano, aminoácidos totais e proteínas solúveis totais. Pelos resultados, observou-se redução na concentração de triptofano e aumento na concentração de aminoácidos totais e proteínas solúveis totais após a pulverização com Zn.
Atividade fotossintética e peroxidação de lipídios de membrana em plantas de aroeira-do-sertão sob estresse hídrico e após reidratação
Authors: Queiroz Cristina G. S. , Garcia Queila S. , Lemos Filho José Pires
Published: April 2005

Avaliaram-se os efeitos do estresse hídrico e da reidratação sobre parâmetros de fluorescência, condutância estomática e peroxidação de lipídios em plantas de Myracrodruon urundeuva Fr. All. (Anacardiaceae). As plantas foram cultivadas em casa de vegetação e a seca foi induzida por suspensão da irrigação durante 14 dias. Sob estresse hídrico, observou-se queda acentuada no conteúdo relativo de água foliar, o qual alcançou valores próximos a 60 %. Essa queda foi acompanhada por grande diminuição na condutância estomática e na taxa aparente de transporte de elétrons (ETR) e extensivos danos às membranas evidenciados por aumentos na peroxidação de lipídios. Apesar do decréscimo nos valores de ETR, não se observaram alterações nos valores do rendimento quântico potencial do fotossistema II (Fv/Fm) em conseqüência do estresse hídrico. Durante a fase de recuperação, as plantas apresentaram valores de condutância estomática, parâmetros de fluorescência e peroxidação lipídica similares àqueles verificados antes do período de seca. Todos os parâmetros fotossintéticos investigados mostraram valores normais 6h após o início de reidratação. O ajuste linear entre os valores de condutância e ETR mostrou alta correlação entre essas duas variáveis, sugerindo que os estômatos representam o principal fator limitante da fotossíntese em plantas de Myracrodruon urundeuva sob estresse hídrico.
Plant-insect interactions: an evolutionary arms race between two distinct defense mechanisms
Authors: Mello Marcia O. , Silva-Filho Marcio C.
Published: April 2005

In this review, plant-insect interaction is discussed as a dynamic system, subjected to continual variation and change. Plants developed different mechanisms to reduce insect attack, including specific responses that activate different metabolic pathways which considerably alter their chemical and physical aspects. On the other hand, insects developed several strategies to overcome plant defense barriers, allowing them to feed, grow and reproduce on their host plants. This review foccuses on several aspects of this complex interaction between plants and insects, including chemical-derived substances, protein-derived molecules and volatile compounds of plants whereas metabolization, sequestration or avoidance are in turn employed by the insects.
Lysine catabolism: flow, metabolic role and regulation
Authors: Fornazier Ricardo Francisco , Azevedo Ricardo Antunes , Ferreira Renato Rodrigues , Varisi Vanderlei Aparecido
Published: April 2005

Lysine is an essential amino acid, synthesized in plants in the aspartic acid pathway. The lysine catabolism is performed by the action of two consecutive enzymes, lysine 2-oxoglutarate reductase (LOR) and saccharopine dehydrogenase (SDH). The steady state of lysine is controlled by both, synthesis and catabolism rates, with the final soluble lysine concentration in cereal seeds a direct result of these processes. In the last 40 years, the enzymes involved in lysine biosynthesis have been purified and characterized from some plant species such as carrot, maize, barley, rice, and coix. Recent reports have revealed that lysine degradation might be related to various physiological processes, for instance growth, development and response to environmental changes and stress. The understanding of the regulatory aspects of the lysine biosynthetic and catabolic pathways and manipulation of related enzymes is important for the production of high-lysine plants.
Leaf anatomy and carbon isotope composition in Coffea species related to photosynthetic pathway
Authors: Carelli Maria Luiza Carvalho , Queiroz-Voltan Rachel Benetti , Fahl Joel Irineu , Trivelin Paulo César Ocheuze
Published: April 2005

Possible presence of vascular bundle sheath cells and its relation to photosynthetic pathway, leaf anatomy and carbon isotope composition (delta13C) were examined in six species of genus Coffea: C. arabica (cvs. Catuaí Vermelho, Mundo Novo, Bourbon Vermelho and Icatu Amarelo), C. canephora (cvs. Apoatã and Guarini), C. liberica, C. dewevrei, C. salvatrix and C. stenophylla. In all genotypes, the vascular bundle was surrounded by a layer of cells with numerous chloroplasts in a centrifugal position. Visually no differences could be seen between the spongy parenchyma cells and the bundle sheath cells, neither in size nor in chloroplast number. The leaf delta13C values ranged between a maximum of - 26.2 ‰ in C. salvatrix and a minimum of -29.7 ‰ in C. liberica. A strong correlation (r = 0.972, p = 0.001) between delta13C and anatomical characteristics was observed in coffee species. C. salvatrix exhibited the highest delta13C values and the most compact mesophyll, with more palisade and spongy parenchyma cells in contact with the vascular bundle sheath.
Multiple shoot formation in Hypericum perforatum L.and hypericin production
Authors: Santarém Eliane Romanato , Astarita Leandro Vieira
Published: April 2005

Hypericum perforatum is a traditional medicinal plant with wound healing and antidepressive properties. Among the secondary compounds of interest is hypericin, a naphtodianthrone that seems to participate in the medicinal effects of this species. The aim of this work was to obtain an efficient micropropagation system of H. perforatum and to compare the hypericin content between in vitro and field-grown plants. Cultures were initiated from nodal segments of mature plants inoculated onto MS medium supplemented with 4.5 muM BA, kinetin, thidiazuron, individually or in combination with 0.05 muM NAA. Organogenic explants were observed on medium with either BA or kinetin alone or in combination of these with NAA. Subculture of organogenic explants onto the proliferation medium containing 4.5 muM BA promoted the organogenic response. The highest average of shoot production (52.6 shoots) was obtained on those explants induced in the presence of BA and NAA. Rooted plantlets were successfully acclimated. Analysis of hypericin contents showed that levels found in callus represented only 0.11 % of what was detected in adult plants, while shoots and leaves from in vitro plants showed similar hypericin levels to those found in the leaves of the field-grown plants, suggesting that the accumulation of this compound is related to leaf differentiation.
CO2 assimilation, photosynthetic light response curves, and water relations of 'Pêra' sweet orange plants infected with Xylella fastidiosa
Authors: Habermann Gustavo , Machado Eduardo Caruso , Rodrigues João Domingos , Medina Camilo Lázaro
Published: April 2005

Plants with citrus variegated chlorosis (CVC), a disease caused by the xylem-limited bacteria Xylella fastidiosa, have leaves with water deficiency symptoms and are associated with decreases on the net photosynthesis and transpiration rates. Using healthy and CVC-affected 'Pêra' sweet orange plants on 'Rangpur' lime rootstock, the leaf gas exchange variables were measured with an open-gas portable photosynthesis system. All plants were watered and the leaf water potential (Yw) was measured by isopiestic thermocouple psychrometric technique. The net photosynthesis (A) vs. internal leaf CO2 concentration (A/Ci curves) was analyzed. The relative effect of stomatal resistance on photosynthesis (S%) and the estimation of carboxylation efficiency were calculated. The rates of photosynthesis and transpiration, stomatal conductance, and internal leaf CO2 concentration (Ci) were also measured while varying the photosynthetic photon flux density (PPFD). The S% values were approximately 30 % greater in infected plants when compared to healthy ones. The light compensation point for diseased plants was higher than in the healthy ones, and the saturation light point in plants with CVC was twofold lower. The lower Yw in diseased plants favours the hypothesis of xylem occlusion, which probably caused a lower water supply to the mesophyll, thus decreasing the photosynthesis and transpiration rates. Nevertheless, there was also a reduction in the photosynthetic metabolic activities, represented by lower carboxylation efficiency and photochemical disturbances that were detected in diseased plants.
Purification and partial characterization of a lectin from Caesalpinia tinctoria Domb, ex Dc fruits
Authors: Oliveira Marli Lourdes de , Beltramini Leila Maria , Simone Salvatore Giovanni de , Brumano Maria Helena Nasser , Silva-Lucca Rosemeire Aparecida , Nakaema Marcelo Kiyoshi Kian , Pires Christiano Vieira , Oliveira Maria Goreti de Almeida
Published: April 2005

A lectin was isolated from the pod saline extract of Caesalpinia tinctoria by dialoconcentration on Centripep-10 and affinity chromatography on chitin column. The purified lectin was partially characterized with respect to its biochemical and structural properties. It contains 8.3 % of carbohydrate and exhibited an agglutinating activity against human erythrocytes (ABO groups). Its amino acid composition was characterized by a great number of acidic and hydrophobic residues and the estimated molecular mass was 12.5 kDa. The presence of only one N-terminal amino acid sequence (D¹-V-P-A-Y-V-Y-V-H-F10-G-F-G-E-E-H-R -D-V-F20-D), showed the homogeneity of the purified lectin. The far-ultraviolet circular dichroism (CD) spectrum of lectin indicated that it contains 10 % a-helix, 38 % b-sheet, 28 % unordered form and 6 % of P II (poly-L-proline II helix conformation).
Cell wall hydrolases in the seeds of Euphorbia heterophylla L. during germination and early seedling development
Authors: Suda Cecilia N. K. , Buckeridge Marcos S. , Giorgini Jarbas F.
Published: April 2005

Activities of cell wall hydrolases of Euphorbia heterophylla L. (wild poinsettia) endosperm were investigated during pre- and post-emergence periods, defined as the time interval before and after 2.2 days from the start of imbibition, respectively. The activities of endo-beta-mannanase and beta-mannosidase are higher over the pre-emergence when compared to the post-emergence period and they may be involved in the process of germination in E. heterophylla. On the other hand, the activities of beta-galactosidase, beta-glucosidase, alpha-xylosidase, beta-xylosidase and glucanases, which hydrolyse CMC, xyloglucans from Hymenaea courbaril or Copaifera langsdorffii, xylan, Avicel and lichenan, are higher over the post-emergence period. Activity on laminarin occurs over both periods. The activity of xyloglucanases was promoted in the presence of oligosaccharide XXLG. E. heterophylla endosperm surrounds the embryo and their cotyledons, which increases in area after 1 day from the start of imbibition. Rather than the mobilization of cell wall reserves the activity of hydrolases over the post-emergence period may be related to facilitation of cotyledon expansion by lowering endosperm resistance. The fraction of water-soluble polysaccharides extracted from the seed coat is composed of mannose (15.9 %), galactose (20.5 %), and glucose (63.6 %) whereas the fraction from decoated seed is composed of glucose (11.0 %), galactose (36.9 %) and xylose (47.9 %).
Apoplasm hydrostatic pressure on growth of cylindrical cells
Authors: Pessoa José Dalton Cruz , Calbo Adonai Gimenes
Published: April 2005

According to the model frequently used as reference, plant cell growth occurs only when turgor surpasses a threshold. This model was proposed considering a cylindrical cell of constant wall thickness immerged in a water solution, with viscoelastic behaviour, hydraulic conductivity, variable extensibility, and unidirectional elongation. The author, Lockhart (1965), did not consider the effects of apoplasm hydrostatic potential, a subject treated later by Calbo and Pessoa (1994) who argued that this component of cell potential would interfere with cell growth rate. To evaluate this effect, where possible the same deductive procedures as those employed by Lockhart were used here, which resulted in a set of equivalent equations for cell growth, turgor and water potential, developed with respect to physico-chemical variables. Relationships were derived from the conductivity equation, the definition of extensibility, Hook's law, and considering that the tension on cell wall transversal section is proportional to turgor and apoplasm hydrostatic potential. The numeric solutions for the equations showed that suction increased extension rate at the beginning of cell growth. Some experiments on plant growth and structural models of cell walls are discussed to point out the role of suction on wall tensioning and cell hydration during cell elongation.
Effects of salt stress on plant growth, stomatal response and solute accumulation of different maize genotypes
Authors: Azevedo Neto André Dias de , Prisco José Tarquinio , Enéas-Filho Joaquim , Lacerda Claudivan Feitosa de , Silva José Vieira , Costa Paulo Henrique Alves da , Gomes-Filho Enéas
Published: April 2005

Seeds from eight different maize genotypes (BR3123, BR5004, BR5011, BR5026, BR5033, CMS50, D766 and ICI8447) were sown in vermiculite, and after germination they were transplanted into nutrient solution or nutrient solution containing 100 mmol.L-1 of NaCl and placed in a greenhouse. During the experimental period plant growth (dry matter, shoot to root dry mass ratio, leaf area, relative growth rate, and net assimilation rate), leaf temperature, stomatal conductance, transpiration, predawn water potential, sodium, potassium, soluble amino acids and soluble carbohydrate contents were determined in both control and salt stressed plants of all genotypes studied. Salt stress reduced plant growth of all genotypes but the genotypes BR5033 and BR5011 were characterized as the most salt-tolerant and salt-sensitive, respectively. Stomatal response of the salt-tolerant genotype was not affected by salinity. Among the studied parameters, shoot to root dry mass ratio, leaf sodium content and leaf soluble organic solute content showed no relation with salt tolerance, i.e., they could not be considered as good morpho-physiological markers for maize salt tolerance. In contrast, sodium and soluble organic solutes accumulation in the roots as a result of salt stress appeared to play an important role in the acclimation to salt stress of the maize genotypes studied, suggesting that they could be used as physiological markers during the screening for salt tolerance.
The effects of salt stress on growth, nitrate reduction and proline and glycinebetaine accumulation in Prosopis alba
Authors: Meloni Diego Ariel , Gulotta Marta Rosalía , Martínez Carlos Alberto , Oliva Marco Antonio
Published: April 2005

Prosopis alba (algarrobo) is one of the most important salt-tolerant legumes used in the food and furniture industries. The effects of salinity on some growth and physiological parameters in algarrrobo seedlings were investigated. 17-Day-old seedlings were subjected to three salt treatments by adding NaCl to the growth medium in 50 mmol.L-1 increments every 24 h until the final concentrations of 0, 300 and 600 mmol.L-1 were reached. Only the highest NaCl concentration affected all of the considered parameters. Thus, 600 mmol.L-1 NaCl caused a significant reduction in root and shoot growth, but an increase in the root/shoot ratio. Leaf relative water content, nitrate content and nitrate reductase activity in leaves and roots were also decreased. At 300 and 600 mmol.L-1, the glycinebetaine content was significantly increased in both leaves and roots but this was not found for proline content. Total soluble carbohydrates increased only in roots. The results suggest that glycinebetaine enhancement may be important for osmotic adjustment in Prosopis alba under salinity stress.
Narrow band spectral indexes for chlorophyll determination in soybean canopies [Glycine max (L.) Merril]
Authors: Ferri Clotilde Pinheiro , Formaggio Antonio Roberto , Schiavinato Marlene Aparecida
Published: April 2005

Photosynthetic pigments are essential for plant development. Quantifying these pigments in great extensions of agricultural crops is an important objective in remote sensing for agricultural purposes. This information can be used to produce a more accurate estimation of the physiological state of the vegetation, for species discrimination and productivity estimation. The aim of the present study was to (a) evaluate the potential for estimating chlorophyll content of crop canopies, using narrow band spectral indexes, and (b) in this respect compare the performances of NDVI (a multispectral wide band index) and two narrow band vegetation indexes (R750/700 and R750/550). Experiments were carried out under greenhouse conditions whereby soybean [Glycine max (L.), Merril] was monitored with a high-resolution spectroradiometer (10 nm at 365-1,126 nm range) during the phenological cycle of the crop. Chlorophyll (a, b and total) contents were determined weekly in the laboratory. A statistical correlation analysis was performed between narrow band spectral indexes against chlorophyll content and r² coefficients near 0.84 were obtained. For NDVI r² was around 0.51. These analyses showed that R750/700 and R750/550 ratios are very useful indexes for chlorophyll determination and very effective compared with NDVI (one of the wide band indexes widely used). Thus, it can be stated that hyperspectral remote sensing has great potential for providing a reliable estimate of photosynthetic pigment content at the canopy level through evaluated indexes and other such indexes that might arise. Thus, further studies should be carried out for evaluating other indexes at the canopy level, both in the laboratory and under field conditions, using spectroradiometers and hyperspectral images, aimed at providing information for agricultural purposes.
Growth, photosynthesis, nodule nitrogen and carbon fixation in the chickpea cultivars under salt stress
Authors: Garg Neera , Singla Ranju
Published: April 2005

Four cultivars of chickpea, two of them of Mediterranean origin (kabuli), CSG 9651, BG 267 and two Indian (desi) types, CSG 8962, DCP 92-3, differing in their salt sensitivities were identified after screening ten genotypes in saline soils. The cultivars CSG 9651 and CSG 8962 were salt tolerant while BG 267 and DCP 92-3 were salt sensitive, respectively. The seeds of different cultivars were inoculated with Mesorhizobium ciceri, strain F: 75 and the plants were grown in the greenhouse. After the establishment of symbiosis, 15-day-old seedlings were administered doses of saline at varying concentrations (0, 4, 6, 8 dSm-1 NaCl, Na2SO4, CaCl2). Plants were harvested at 40, 70 and 100 days after sowing, for analyses. The main aim was to compare the relative salt tolerance of both desi and kabuli cultivars in terms of nitrogen fixation and carbon metabolism, as well as to ascertain whether the negative effects of saline stress on nitrogen fixation were due to a limitation of photosynthate supply to the nodule or to a limitation on the nodular metabolism that sustains nitrogenase activity. Plant growth, nodulation and nitrogenase activity was more severely affected in BG 267 and DCP 92-3 under salinity treatments (6 and 8 dSm-1) compared with CSG 9651 and CSG 8962. Nodule number as well as nodule mass increased under salt stress in CSG 9651 and CSG 8962 which might be responsible for their higher nitrogen fixation. Salinity reduced leaf chlorophyll and Rubisco activities in all cultivars. However, tolerant cultivars CSG 9651 and CSG 8962 showed smaller declines than the sensitive ones. Phosphoenolpyruvate carboxylase (PEPCase) activity increased significantly in the nodules of tolerant cultivars under salt stress at all harvests, and this was clearly related to salt concentrations. Our results suggest that in salt-affected soils tolerant cultivars have more efficient nodulation and support higher rates of symbiotic nitrogen fixation than the sensitive cultivars.
Photoelastic analysis of stress distribution on parallel and angled implants after installation of fixed prostheses
Authors: Ueda Cristiane , Markarian Roberto Adrian , Sendyk Cláudio Luiz , Laganá Dalva Cruz
Published: April 2005

The longevity of implant-supported prosthetic rehabilitation depends largely on how the masticatory forces are transferred to the implants and surrounding bone. Anatomical conditions, bone morphology and aesthetics usually dictate implant placement in less than ideal positions for prosthetic rehabilitation and sometimes it is possible to find them with different inclinations. The purpose of this paper was to compare, through photoelastic analysis, the stress distribution in a fixed prosthesis with 3 parallel implants, to the stress distribution in the same prosthesis in the existence of an angled central implant. Two photoelastic resin models were made and a polariscope was used in the visualization of isochromatic fringes formed in the models when axial loads of 2 kg, 5 kg and 10 kg were applied to a unique central point of the prosthesis. The presence of inducted tensions (preloads) was observed in the models after applying torque to the retention screws. Preloads were intensified with the incidence of occlusal forces. In the parallel implants, the force dissipation followed the long axis. The angled implant had a smaller quantity of fringes and the stresses were located mostly around the apical region of the lateral implants.
Clinical and biochemical evaluation of the saliva of patients with xerostomia induced by radiotherapy
Authors: Pontes Cássio de Barros , Polizello Ana Cristina Morseli , Spadaro Augusto César Cropanese
Published: April 2005

Clinical aspects and biochemical properties in the saliva of 21 patients prior to and following radiotherapy for head and neck cancer were evaluated (experimental group) and compared with the same properties in a control group of 21 subjects free of cancer. Salivary flow was evaluated by measuring the time necessary, in seconds, for the output of 2 ml of stimulated saliva; and the buffering capacity changes were determined using a simple colorimetric method. Total salivary protein concentration was determined by the Bradford4 method. Amylase activity was measured by reducing sugars released from a soluble starch substrate, quantified by the dinitrosalicylic method. The electrophoretic profile was evaluated in polyacrylamid gel (12% SDS-PAGE) using samples of 5 mg of salivary protein. A statistically significant reduction (p < 0.01) of the salivary flow was observed, (162.47 s ± 28.30 before and 568.71 s ± 79.75 after irradiation), as well as a reduction in the salivary buffering capacity (pH 5.45 ± 0.14 before and pH 4.40 ± 0.15 after irradiation). No statistically significant alteration was observed in total salivary protein concentration. A statistically significant reduction (p < 0.01) of salivary a-amylase activity (856.6 ng/mg ± 88.0 before and 567.0 ng/mg ± 120.6 after irradiation) was observed. Electrophoretic profile differences in salivary protein bands were also observed after radiotherapy, mainly in the range of molecular weight of 72,000 to 55,000 Daltons. Clinically, patients presenting xerostomia induced by radiotherapy presented an increase in oral tissue injury.
Influence of post-bleaching time intervals on dentin bond strength
Authors: Teixeira Erica Cappelletto Nogueira , Turssi Cecilia Pedroso , Hara Anderson Takeo , Serra Mônica Campos
Published: April 2005

It has been reported that bond strength of resin to tooth structure can be reduced when the bonding procedure is carried out immediately after the bleaching treatment. This study evaluated the effect of bleaching of non-vital teeth bleaching on the shear bond strength (SBS) of composite resin/bovine dentin interface and the influence of delaying the bonding procedures for different time intervals following internal bleaching. According to a randomized block design, composite resin cylinders (Z100/Single bond - 3M) were bonded to the flattened dentin surface of two hundred and fifty-six teeth which had previously been subjected to four different treatments: SPH - sodium perborate + 30% hydrogen peroxide; SPW - sodium perborate + distilled water; CP - 37% carbamide peroxide; and CON - distilled water (control), each one followed by storage in artificial saliva for 0 (baseline), 7, 14, and 21 days after bleaching (n = 16). The bleaching agents in the pulp chambers were replaced every 7 days, over 4 weeks. The SBS test of the blocks was done using a universal testing machine. The ANOVA showed that there was no significant interaction between time and bleaching agents, and that the factor time was not statistically significant (p > 0.05). For the factor bleaching treatment, the Student's t-test showed that [CON = CP] > [SPW = SPH]. The bleaching of non-vital teeth affected the resin/dentin SBS values when sodium perborate mixed with 30% hydrogen peroxide or water was used, independently of the elapsed time following the bleaching treatment.
Evaluation of the Image-Pro Plus 4.5 software for automatic counting of labeled nuclei by PCNA immunohistochemistry
Authors: Francisco Jairo Silva , Moraes Heleno Pinto de , Dias Eliane Pedra
Published: April 2005

The objective of this study was to create and evaluate a routine (macro) using Image-Pro Plus 4.5 software (Media Cybernetics, Silver Spring, USA) for automatic counting of labeled nuclei by proliferating cell nuclear antigen (PCNA) immunohistochemistry. A total of 154 digital color images were obtained from eleven sections of reticular oral lichen planus stained by PCNA immunohistochemistry. Mean density (gray-level), red density, green density, blue density, area, minor axis, perimeter rate and roundness were parameters used for PCNA labeled nuclei discrimination, followed by their outlined presentation and counting in each image by the macro. Mean density and area thresholds were automatically defined based, respectively, on mean density and mean area of PCNA labeled nuclei in the assessed image. The reference method consisted in visual counting of manually outlined labeled nuclei. Statistical analysis of macro results versus reference countings showed a very significant correlation (r s = 0.964, p < 0.001) for general results and a high level (89.8 ± 3.8%) of correctly counted labeled nuclei. We conclude that the main parameters associated with a high correlation between macro and reference results were mean density (gray-level) and area thresholds based on image profiles; and that Image-Pro Plus 4.5 using a routine with automatic definition of mean density and area thresholds can be considered a valid alternative to visual counting of PCNA labeled nuclei.
Clinical and microbial evaluation of dental scaling associated with subgingival minocycline in chronic periodontitis subjects
Authors: Querido Silvia Maria Rodrigues , Cortelli Sheila Cavalca , Araújo Marcelo Werneck Barata de , Cortelli José Roberto
Published: April 2005

The aims of this double-blind randomized clinical trial were to evaluate the presence of periodontal pathogens and the clinical response of periodontal pockets treatment to scaling and root planing (SRP) associated with subgingival minocycline (SM). A total of 36 subjects, 26 to 60 years old (40.7 ± 9.1), who had been previously diagnosed with chronic periodontitis, were included in the present study. Eighteen subjects were selected for the test group (TG), who were treated with SRP plus SM (new treatment), and 18 subjects for the control group (CG) who received SRP plus vehicle (current treatment). Two homologous sites in each subject with a probing depth (PD) > 6 mm were chosen. To evaluate the clinical response after treatment, PD was measured at baseline and at 90 days. Microbiological evaluation was performed to detect 7 periodontal pathogens using polymerase chain reaction at baseline, 30, and 120 days. A mean reduction in PD of 2.8 and 2.1 mm was observed in the TG and CG, respectively. At baseline, P. gingivalis was the most prevalent organism in both test (65.8%) and control (48.6%) groups. After 120 days it fell to 30.8% in TG and to 23.1% in CG. There were no statistically significant differences between the test and control groups concerning PD (p > 0.05 by Wilcoxon test) or presence of periodontal pathogens (p > 0.05 by Wilcoxon and chi-square; p > 0.01 by Signal test). The results observed showed that the new treatment was as effective as the current treatment in reducing periodontal pathogens and PD among chronic periodontitis subjects.
Natural medicaments in endodontics: a comparative study of the anti-inflammatory action
Authors: Silva Fabiane Bortoluci da , Almeida Juliano Milanezi de , Sousa Simone Maria Galvão de
Published: April 2005

The objective of this study was to evaluate the irritant potential of propolis, Casearia sylvestris, Otosporin and saline solution (control). Twenty-eight male Wistar rats were selected, anesthetized and four experimental sites were designed on their backs. Injections of 2% Evans blue were intravenously administered in the lateral caudal vein and 0.1 ml of the tested solutions was injected intradermally into the experimental sites. The animals were killed 1/2, 1, 3 and 6 hours after the injection of the solutions. Each piece of skin containing the lesion was immersed in formamide and incubated at 45ºC for 72 h. After filtration, optical density was measured in a spectrophotometer. Data were statistically analyzed by a 2-way non-parametric test. The highest values of extracted dye were observed at 3 hours characterizing a peak in the inflammatory process. Propolis was the least irritant solution. The natural medicaments tested in this study may be a valuable alternative for endodontic treatment.
Fluoride does not induce DNA breakage in Chinese hamster ovary cells in vitro
Authors: Ribeiro Daniel Araki , Scolastici Clarissa , Marques Mariângela Esther Alencar , Salvadori Daisy Maria Fávero
Published: April 2005

Fluoride has been widely used in dentistry because it is a specific and effective caries prophylactic agent. However, excess fluoride may represent a hazard to human health, especially by causing injury to genetic material. Genotoxicity tests represent an important part of cancer research to assess the risk of potential carcinogens. In the current study, the potential DNA damage associated with exposure to fluoride was assessed by the single cell gel (comet) assay in vitro. Chinese hamster ovary cells were exposed to sodium fluoride (NaF) at final concentration ranging from 7 to 100 µg/ml for 3 h, at 37°C. The results pointed out that NaF in all concentrations tested did not contribute to DNA damage as depicted by the mean tail moment and tail intensity. These findings are clinically important since they represent an important contribution to a correct evaluation of the potential health risk associated with the exposure to dental agents.
Prevalence of yeasts in the oral cavity of children treated with inhaled corticosteroids
Authors: Komiyama Edson Yukio , Ribeiro Patrícia Monteiro , Junqueira Juliana Campos , Koga-Ito Cristiane Yumi , Jorge Antonio Olavo Cardoso
Published: April 2005

The aim of this study was to observe the prevalence of Candida spp. in the oral cavity of children undergoing treatment with inhaled corticosteroids. Thirty children treated with inhaled corticosteroids and thirty control children were studied. Saliva samples were collected through oral rinses with phosphate buffered saline (PBS). The samples were plated on Sabouraud's dextrose agar and incubated at 37°C for 48 h. After this period, the number of colony-forming units per ml (cfu/ml) of saliva was calculated. The isolates were identified by phenotypic characterization. Candida spp. was isolated from 43.33% of the samples of children treated with corticosteroids, with a mean of 780 cfu/ml of saliva, and from 30% of the samples of the control group, with a mean of 560 cfu/ml of saliva. No significant statistical difference was observed between the groups. C. albicans was the prevalent species in both groups, followed by C. guilliermondii, C. parapsilosis and C. stellatoidea. Furthermore, Rhodotorula rubra and C. lusitaniae were also isolated from the treated group. We concluded that there was no significant increase in the prevalence and number of Candida spp. in the oral cavity of children treated with inhaled corticosteroids.
Substitution of amalgam restorations: participative training to standardize criteria
Authors: Fernandes Elaine Toledo Pitanga , Ferreira Efigênia Ferreira e
Published: April 2005

Considering that the variations on clinical judgment with respect to replacement of restorations are a problem which affects dentistry, the aim of this study was to elaborate, implement and evaluate a programme of participative training to standardize criteria for the evaluation of amalgam restorations. Five professors of Integrated Clinic of the School of Dentistry of the University of Vale do Rio Doce (UNIVALE), Brazil, visually and radiographically evaluated 28 extracted permanent teeth presenting amalgam restorations. The research was developed in four distinct phases: first - the teeth were evaluated according to individual criteria to determine whether restorations should be replaced or not; second - the examiners participated in a training programme with the objective of standardizing the evaluation criteria; third - soon after the training, the teeth were re-evaluated using the adopted standardized criteria; fourth - five months after the training, the procedures on third phase were repeated. For each restoration the examiners registered the main reason for considering the restoration: satisfactory, requiring total substitution, requiring partial substitution or requiring finishing/polishing. After participating in the training programme the examiners presented a statistically significant reduction (sign test: Z = 0.4989, p = 0.0022) in indicating the need to substitute restorations, result which was maintained five months after training. This programme of participative training can be organized and implemented to standardize the criteria to evaluate amalgam restorations achieving satisfactory results with an impact on clinical practice.