The relationship between environmental variation and species abundance in shrimp community (Crustacea : Decapoda : Penaeoidea) in south-eastern Brazil

The impact of shrimp fisheries in tropical regions has become comparable to the world's most intensively exploited temperate shed ecosystems. The increase in the fishing fleet in south-eastern Brazil and the decrease in landings of profitable shrimp species have contributed to the incorporation of additional species into those fisheries. The goal of the present study is to investigate the influence of environmental factors on the abundance patterns of shrimp communities on the south-eastern coast of Brazil, over a period of two years. Monthly collections were conducted in the Ubatuba and Caraguatatuba regions using a commercial shrimp fishing boat equipped with 'double-rig' nets. Each region was divided into 7 sampling stations up to 35 m deep. The relationship between the environmental factors and the abundance patterns in the shrimp communities was assessed using a canonical correlation analysis (CCorrA). The first set of variables used during the CCorrA included environmental characteristics and the second set of variables the abundance of the studied species. A total of 374,915 individuals were collected during the present study. Xiphopenaeus kroyeri showed the highest abundance (273,127), followed by Artemesia longinaris (73,422), and Pleoticus muelleri (15,262). In the first root, depth and temperature showed the highest factor loadings (0.9 and -0.7) and canonical weights (0.6 and -0.4). These environmental factors were strongly associated with the abundance of X. kroyeri (factor loading = - 0.9 and canonical weight = - 0.9). The second root demonstrated a positive relationship between abundance of P. muelleri and depth, and an inverse association with bottom temperature. The abundance patterns of X. kroyeri and P. muelleri were strongly affected by the water mass South Atlantic Central Water (cold waters =15 degrees C), which can lead to a temperature decrease in deeper areas (> 15 m). Thus, the opposite abundance trend for depth of these species might reflect bathymetric variation in temperature, a clear example of distinct behavioural differences of species of different origins, either tropical (X. kroyeri) or subantarctic (P. muelleri). The low overall association between environmental parameters and shrimp abundance patterns indicates that each studied species might have responded idiosyncratically to environmental variation, such that a general community-level response was not apparent. However, other confounding factors such as intraspecific migration patterns might have also played a role in generating the observed patterns.

Seed size variation in the palm Euterpe edulis and the effects of seed predators on germination and seedling survival

Intraspecific variation in seed size is common in wild plant populations and has important consequences for the reproductive success of individual plants. Multiple, often conflicting evolutionary forces mediated by biotic as well as abiotic agents may maintain such a variation. In this paper we assessed seed size variation in a population of the threatened, commercially important palm Euterpe edulis in southeast Brazil. We investigated (i) how this variation affects the probability of attack by vertebrate and invertebrate post-dispersal seed predators, and (ii) if seed size influences the outcome of seeds damaged by beetles in terms of seed germination and early survival of seedlings. Euterpe edulis seeds varied in diameter from 8.3 to 14.1 mm. Neither insects nor rodents selected the seeds they preyed upon based on seed size. Seed germination and total, shoot and root biomasses of one-year seedlings were significantly and positively affected by seed size. Root biomass and seedling survival were negatively affected by seed damage caused by a scolytid beetle (Coccotrypes palmarum) whose adults bore into seeds to consume part of the endosperm, but do not oviposit on them. Seed size had a marginally significant effect on seedling survival. Therefore, if any advantage is accrued by E. edulis individuals producing large seeds, this is because of greater seed germination success and seedling vigor. If this is so, even a relatively narrow range of variation in seed size as observed in the E. edulis population studied may translate into differential success of individual plants. (c) 2006 Elsevier SAS. All rights reserved.

Meristematic activity of the Endodermis and the Pericycle in the primary thickening in monocotyledons: considerations on the PTM

A proposta deste trabalho é mostrar uma nova interpretação do meristema de espessamento primário em monocotiledôneas. Anatomia dos órgãos vegetativos das seguintes espécies foi examinada: Cephalostemon riedelianus (Rapataceae), Cyperus papyrus (Cyperaceae), Lagenocarpus rigidus, L. Junciformis (Cyperaceae), Echinodorus paniculatus (Alismataceae) and Zingiberofficinale (Zingiberaceae). A atividade meristemática da endoderme foi observada nas raizes de todas as espécies, no caule de Cyperus, Cephalostemum e Lagenocarpus rigidus, e no traço foliar de Cyperus e folha de Echinodorus. Considerando a continuidade dos tecidos através da raiz, caule e folha, as autoras concluem que no caule o periciclo permanece ativo durante a vida da planta, como um gerador de tecidos vasculares. O Meristema de Espessamento Primário é o periciclo em fase meristemática, juntamente com a endoderme e suas derivadas (ou apenas o periciclo). Próximo ao ápice caulinar, esses tecidos se assemelham a um único meristema, dando origem ao córtex interno e aos tecidos vasculares.

Resistance to compression of weakened roots subjected to different root reconstruction protocols

Objective: This study evaluated, in vitro, the fracture resistance of human non-vital teeth restored with different reconstruction protocols. Material and methods: Forty human anterior roots of similar shape and dimensions were assigned to four groups (n=10), according to the root reconstruction protocol: Group I (control): non-weakened roots with glass fiber post; Group II: roots with composite resin by incremental technique and glass fiber post; Group III: roots with accessory glass fiber posts and glass fiber post; and Group IV: roots with anatomic glass fiber post technique. Following post cementation and core reconstruction, the roots were embedded in chemically activated acrylic resin and submitted to fracture resistance testing, with a compressive load at an angle of 45 degrees in relation to the long axis of the root at a speed of 0.5 mm/min until fracture. All data were statistically analyzed with bilateral Dunnett's test (alpha=0.05). Results: Group I presented higher mean values of fracture resistance when compared with the three experimental groups, which, in turn, presented similar resistance to fracture among each other. None of the techniques of root reconstruction with intraradicular posts improved root strength, and the incremental technique was suggested as being the most recommendable, since the type of fracture that occurred allowed the remaining dental structure to be repaired. Conclusion: The results of this in vitro study suggest that the healthy remaining radicular dentin is more important to increase fracture resistance than the root reconstruction protocol.

The Oxidation of Hydroxylamine on Gold Electrodes in Mildly Acidic Aqueous Electrolytes: Electrochemical and In Situ Differential Reflectance Studies

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Qualitative determination of indole alkaloids, triterpenoids and steroid of Tabernaemontana hilariana

This paper reports the separation and identification of indole alkaloids, steroids and triterpenoids from the ethanolic extracts of Tabernaemontana hilariana (Apocynaceae). The alkaloidal fractions from the ethanolic extracts obtained (root barks, green fruits, ripe fruits and seeds) were fractionated and analysed by thin-layer chromatography, capillary gas chromatography-flame ionization detection (cGC-FID) as well as by high-resolution gas chromatography-mass spectrometry (HRGC-MS). 3-Hydroxycoronaridine, ibogamine, coronaridine pseudoindoxyl, coronaridine, catharanthine, voacangine hydroxyindolenine, voacangine pseudoindoxyl, tabernanthine, tetraphyllicine, 3-hydroxyvoacangine, voacangine, isovoacangine and 3-oxocoronaridine were identified. The insoluble fraction of ethanolic extracts obtained from the root barks and green fruits were analysed and ten aliphatic constituents were also identified by cGC-FID and HRGC-MS. (C) 1998 Elsevier B.V. B.V. All rights reserved.

In vitro effects of endodontic irrigants on endotoxins in root canals

Objective. The objective of this study was to evaluate the effects of endodontic irrigants on endotoxins in root canals.Study design. Ninety-eight single-root human teeth were used. Escherichia coli endotoxin was inoculated into 84 root canals. All root canals were enlarged and assigned to 7 groups (n = 14), according to solution used. Group 1 (G1): 2.5% NaOCl; G2: 5.25% NaOCl; G3: 2% chlorhexidine; G4: 0.14% calcium hydroxide; G5: polymyxin B; G6: positive control, saline solution; G7: negative control (no endotoxin). Two samplings of root canal were accomplished: immediate and after 7 days. Detoxification of endotoxin was evaluated by Limulus assay and antibody production in B-lymphocyte culture. Results were analyzed by Kruskal-Wallis/Dunn and ANOVA/Tukey.Results. At the immediate and second samplings, groups G4, G5, and G7 presented the best results, significantly different from groups G1, G2, G3, and G6 (P = .05).Conclusions. Calcium hydroxide and polymyxin B detoxified endotoxin in root canals and altered properties of LPS to stimulate the antibody production by B-lymphocytes. Sodium hypochlorite and chlorhexidine did not detoxify endotoxin.

Effects of Nd : YAG laser irradiation on root canal dentin wall: A scanning electron microscopic study

Objective: the purpose of this study was to evaluate, by scanning electron microscopy (SEM), the effects of Nd:YAG laser irradiation applied perpendicular or parallel to the root canal dentin wall. Methods: Thirty human teeth were divided into two groups: Group A (20 roots), laser application with circular movements, parallel to the dentin root surface; and Group B (10 roots), roots cut longitudinally and laser applied perpendicular to the root surface. Group A was subdivided into A1 (10 roots), laser application with 100 mJ, 15 Hz and 1.5 W; and A2 (10 roots) with 160 mJ, 15 Hz, and 2.4 W. Group B was subdivided into B1 (10 hemisections) and B2 (10 hemi-sections) with parameters similar to A I and A2. Four applications of 7-sec duration were performed, with a total exposure of 28 sec. SEM evaluations were made in the cervical, middle, and apical thirds, with 500X and 2000X magnifications. Morphological changes scores were attributed, and the results were submitted to Kruskal Wallis statistical test (5%). Results: Significant statistical differences were found between groups A and B (p = 0.001). In groups A1 and A2, few areas of dentin melting were observed. In groups B1 and B2, areas of melting dentin covering dentin surface were observed. Conclusions: It was concluded that intracanal laser application with circular movements (parallel to the surface) produces limited morphological changes in root canal dentin wall.

Root-system of peanuts as affected by phosphorus fertilization

There have been some responses of peanut roots to phosphorus. An experiment was carried out to study peanut root growth and distribution as related to P in the soil. The cultivars Tatu, Oira and Tup4 and the lines FCA 170 and FCA 265 were grown with or without P fertilization with 80 kg P2O5/ha, as triple superphosphate. The fertilizer was applied in the seed furrows. There was higher P contents in the 0-10 cm layer of the soil 36 days after P application. At 66 and 98 days after application, P contents of the soil were increased by fertilization down to 15 cm. There was no response of peanut roots to P fertilization. Oira showed the highest root lenght density and Tatu the lowert. There was a root concentration the first 15 cm of the soil. Oira with the largest root system showed the lowest P absorption, and Tatu, with the smallest root system absorbed as much P as the others.

Histopathological observations of periapical repair in teeth with radiolucent areas submitted to two different methods of root canal treatment

Dogs' teeth with induced chronic periapical periodontitis were treated endodontically by two different methods, and the results were compared. A total of 40 root canals from the upper and lower premolars of two dogs were prepared chemomechanically. In method 1, a high-concentration (5.25%) hypochlorite solution was used during the instrumentation of the root canal, and an antibacterial dressing was applied between sessions, followed by filling of the root canal. In method 2, a low-concentration (0.5%) sodium hypochlorite solution was used as an adjunct to mechanical debridement, and the root canal was filled during the same session. The histopathological results showed that method 1 led to better periapical repair than method 2.

In vitro allelopathic effects of extracts and amenthoflavone from Byrsonima crassa (Malpighiaceae)

Extracts and pure amenthoflavone isolated from Byrsonima crassa (Malpighiaceae), a shrub growing in the semi-arid region of Brazil Cerrado, were evaluated in vitro, at different doses, for their effects on tomato seed germination and subsequent growth of seedlings. A hydromethanolic extract showed general stimulatory effects. The EtOAc extract stimulated root elongation and root weight of tomato; shoot elongation was inhibited, while shoot weight was not altered. The pure amenthoflavone isolated from the plant, stimulated shoot elongation at concentrations ranging between 10(-4) M and 10(-6) M.

Histological evaluation of MTA as a root-end filling material

Aim To assess the histological response associated with grey mineral trioxide aggregate (GMTA) and zinc oxide eugenol (ZOE) as root-end filling materials in teeth where the root canals were not filled and the coronal access cavities were not restored.Methodology Periapical lesions were developed in 24 premolar teeth in three dogs. The root canals were prepared and half of them were dried, filled and the coronal access restored (closed). The remaining teeth were not root filled and no coronal restoration was placed (open). Apical root-end resections were performed 3 mm from the apex, and root-end cavities were prepared with ultrasonic tips. These were randomly filled with either ZOE or GMTA in the same number of specimens using MAPSYSTEM device. After 180 days the animals were killed and blocks of tissues removed and processed for histological examination. Periradicular tissue reaction was evaluated, including severity of inflammation and cementum formation. Statistical analysis was performed using ANOVA analysis and Tukey's test.Results A significant difference was found between the levels of inflammation in the periradicular tissues of the GMTA/closed group, compared with the ZOE/open and ZOE/closed groups (P < 0.05) but not between GMTA/closed and GMTA/open groups. Cementum formation was not found over any ZOE specimens but over MTA in all specimens. No microorganisms were found in the interface between the material and the dentinal walls.Conclusions GMTA was associated with less periapical inflammation and tissue response when used as a root-end filling material, even when no root filling or coronal restoration was present.

Kinetics of zinc uptake and anatomy of roots and leaves of coffee trees as affected by zinc nutrition

Zinc (Zn) uptake kinetics and root and leaf anatomy were studied in coffee trees grown in nutrient solutions with or without Zn. Leaves and roots were sampled and cuts were made in the medium part of the leaves and in root tips and observed under an optical microscope. Plants grown without Zn showed an increase in root and in root stele diameter. There was also an increase in epidermis thickness and in the cross-sectional area of the cortex and stele due to Zn deficiency, but the diameter of xylem vessels was decreased. An increase in root cortex and stele diameter provided for an increased surface for nutrient uptake. Accordingly, C(min) was decreased from 13.8 to 3.4 mu mol L(-1) and V(max) increased from 0.50 to 2.1 mu mol cm(-2) h(-1) .

Biosynthesis of friedelane and quinonemethide triterpenoids is compartmentalized in Maytenus aquifolium and Salacia campestris

Maytenus aquifolium (Celastraceae) and Salacia campestris (Hippocrateaceae) species accumulate friedelane and quinonemethide triterpenoids in their leaves and root bark, respectively. Enzymatic extracts obtained from leaves displayed cyclase activity with conversion of the substrate oxidosqualene to the triterpenes, 3 beta -friedelanol and friedelin. In addition, administration of (+/-)5-H-3 mevalonolactone in leaves of M. aquifolium seedlings produced radio labelled friedelin in the leaves, twigs and stems, while the root bark accumulated labelled maytenin and pristimerin. These experiments indicated that the triterpenes once biosynthesized in the leaves are translocated to the root bark and further transformed to the antitumoral quinonemethide triterpenoids. (C) 2000 Elsevier B.V. Ltd. All rights reserved.

Fiber Post Cementation Strategies: Effect of Mechanical Cycling on Push-out Bond Strength and Cement Polymerization Stress

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