Growth and survival of the native oyster Crassostrea gasar cultured under different stocking densities in two grow-out systems in tropical climate / [Crescimento e sobrevivência da ostra nativa Crassostrea gasar cultivada em diferentes densidades em dois sistemas em clima tropical]

Survival and growth of the native oyster Crassostrea gasar along the juvenile and adult phases were evaluated in three different stocking densities [low (D), medium (2D) and high (3D)] and in two grow-out systems (fixed and floating system). The fixed system consisted of a rack made with PVC, fixed from the bottom with wood sticks. The floating system consisted of floating bags suspended by a rack made with PVC and maintained submerged from the seawater surface by eight floats. Survival and shell height of oysters cultured after 30, 60 and 90 days were registered in each phase and in each grow-out system. Results showed that the grow-out system did not affect survival and growth of C. gasar in the juvenile and adult phases. The tested densities affected the survival of oysters cultured over time in both phases but did not affect oyster growth. At times analyzed, it was observed positive growth in juvenile oysters grow after 90 days of culture. However, in the adult phase, no growth was observed after 90 days of culture. Oyster yield was higher in the density 3D, in both juvenile and adult phases. These findings contributed to the development of the oyster C. gasar culture.(AU)

A sobrevivência e o crescimento da ostra nativa Crassostrea gasar nas fases juvenil e adulta foram avaliados sob três diferentes densidades de estocagem [baixa (D), média (2D) e alta (3D)] e dois sistemas de engorda (fixo e flutuante). O sistema fixo consistiu em uma mesa de PVC, fixada na parte inferior com varas de madeira. O sistema flutuante consistiu em travesseiros flutuantes suspensos por uma mesa de PVC e mantidas submersas da superfície da água do mar por oito flutuadores. Registraram-se sobrevivência e altura da concha de ostras cultivadas após 30, 60 e 90 dias, em cada fase (juvenil e adulta) e em cada sistema (fixo e flutuante). Os resultados mostraram que o sistema de engorda não afetou a sobrevivência e o crescimento de C. gasar nas fases juvenil e adulta. As densidades testadas afetaram a sobrevivência das ostras ao longo do tempo, em ambas as fases, mas não afetaram o crescimento em altura. Nos tempos analisados, ostras juvenis apresentaram crescimento após 90 dias de cultivo. Porém, na fase adulta, não foi observado crescimento após 90 dias de cultivo. A produção de ostras, foi maior na densidade 3D, nas fases juvenil e adulta. Os presentes achados contribuíram para o desenvolvimento do cultivo da ostra C. gasar.(AU)

Spatial distribution of nominally herbivorous fishes across environmental gradients on Brazilian rocky reefs.

Assemblages of roving herbivores were consistently different between eastern, warmer, sheltered sites and western, colder, more wave-exposed sites. At eastern sites, detritivorous-herbivorous species dominated while omnivores had the highest biomass and were dominant at western sites. Macroalgivores did not show any trends related to location. These distributional patterns, at relatively small spatial scales of a few kilometres, mirror large-scale latitudinal patterns observed for the studied species along the entire Brazilian coast, where cold water associated species are abundant on south-eastern rocky reefs (analogous to the western sites of this study), and tropical species are dominant on north-eastern coral reefs (analogous to the eastern sites). Species-level analyses demonstrated that depth was an important factor correlated with biomasses of Diplodus argenteus, Sparisoma axillare and Sparisoma tuiupiranga, probably due to resource availability and interspecific competition. Herbivorous fish assemblages in the study area have been historically affected by fishing, and combined with the variation in assemblage structure, this is likely to have important, spatially variable effects on the dynamics of benthic communities.

In vivo continuous and simultaneous monitoring of brain energy substrates with a multiplex amperometric enzyme-based biosensor device.

Enzyme-based amperometric biosensors are widely used for monitoring key biomarkers. In experimental neuroscience there is a growing interest in in vivo continuous and simultaneous monitoring of metabolism-related biomarkers, like glucose, lactate and pyruvate. The use of multiplex biosensors will provide better understanding of brain energy metabolism and its role in neuropathologies such as diabetes, ischemia, and epilepsy. We have developed and characterized an implantable multiplex microbiosensor device (MBD) for simultaneous and continuous in vivo monitoring of glucose, lactate, and pyruvate. First, we developed and characterized amperometric microbiosensors for monitoring lactate and pyruvate. In vitro evaluation allowed us to choose the most suitable biosensors for incorporation into the MBD, along with glucose and background biosensors. Fully assembled MBDs were characterized in vitro. The calculated performance parameters (LOD, LR, LRS, IMAX and appKM) showed that the multiplex MBD was highly selective and sensitive (LRS≥100 nA/mM) for each analyte and within an adequate range for in vivo application. Finally, MBDs were implanted in the mPFC of anesthetized adult male Wistar rats for in vivo evaluation. Following an equilibration period, baseline brain levels of glucose (1.3±0.2 mM), lactate (1.5±0.4 mM) and pyruvate (0.3±0.1 mM) were established. Subsequently, the MBDs recorded the responses of the animals when submitted to hyperglycemic (40% glucose i.v.) and hypoglycemic (5 U/kg insulin i.v.) challenges. Afterwards, MBDs were recalibrated to convert electrochemical readings into accurate substrate concentrations and to assess biofouling. The presented MBD can monitor simultaneously multiple biomarkers in vivo.

Evaluation of solid residues removed from a mangrove swamp in the São Vicente Estuary, SP, Brazil.

Mangrove swamps are found in estuaries along the coastal plains of tropical regions and have be subjected to heavy occupation and use pressure due to their privileged locations and abundance of biological resources. The present work evaluated the ecological characteristics and solid wastes accumulated in eight areas along the Santos - São Vicente Estuary Complex. The superficially deposited residues at each sampling site were collected and subsequently washed, drained, counted, weighed and separated into classes according to their composition and predominant use. The predominant litter type in terms of density was plastic (62.81%) and, by weight, wood (55.53%). The greatest deposition of residues was associated with areas that were less inclined and that had low plant density levels, indicating that the presence of obstacles was not critical for retaining floating residues in mangrove areas. The presence of the most frequently encountered types of solid waste residues could be explained by local activities.

TNF-alpha gene polymorphism (-308G/A) and toxoplasmic retinochoroiditis.

AIM: To investigate the possible association between TNF-alpha (-308G/A) polymorphism and toxoplasmic retinochoroiditis (TR) in humans. METHODS: A cross-sectional study was performed which included 100 Brazilian patients with diagnosis of TR and 100 matched control subjects with positive serology to toxoplasmosis and no sign of uveitis. Genomic DNA was obtained from oral swabs of all subjects and amplified using the polymerase chain reaction (PCR) with specific primers flanking the locus -308 of TNF-alpha. PCR products were submitted to restriction endonuclease digestion and analysed by polyacrylamide gel electrophoresis to distinguish alleles, allowing the determination of the genotypes. RESULTS: There was no significant difference in the genotype (chi(2) = 0.79, p = 0.67), allele (chi(2) = 0.095, p = 0.75) and allele carriage (chi(2) = 0.70, p = 0.40) frequencies in TR patients compared with control subjects. Frequencies of the genotype (chi(2) = 2.05, p = 0.35) and allele (chi(2) = 0.13, p = 0.71) did not differ significantly between TR patients with and without recurrent episodes. CONCLUSION: This is the first study to investigate the association between TNF-alpha polymorphism and the occurrence of TR in humans. TNF-alpha gene polymorphism (-308G/A) does not seem to be associated with the occurrence or recurrence of TR.

Determination of glyoxal and methylglyoxal in environmental and biological matrices by stir bar sorptive extraction with in-situ derivatization.

Stir bar sorptive extraction with in-situ derivatization using 2,3-diaminonaphthalene (DAN) followed by liquid desorption and high performance liquid chromatography with diode array detection (SBSE(DAN)in-situ-LD-HPLC-DAD) was developed for the determination of glyoxal (Gly) and methylglyoxal (MGly) in environmental and biological matrices. DAN proved very good specificity as in-situ derivatising agent for Gly and MGly in aqueous media, allowing the formation of adducts with remarkable sensitivity, selectivity and the absence of photodegradation. Assays performed on spiked (1.0 microg L(-1)) water samples, under convenient experimental conditions, yielded recoveries of 96.2+/-7.9% for Gly and 96.1+/-6.4% for MGly. The analytical performance showed good accuracy, suitable precision (<12.0%), low detection limits (15 ng L(-1) for Gly and 25 ng L(-1) for MGly adducts) and excellent linear dynamic ranges (r2>0.99) from 0.1 to 120.0 microg L(-1). By using the standard addition method, the application of the present method to tap and swimming-pool water, beer, yeast cells suspension and urine samples allowed very good performance at the trace level. The proposed methodology proved to be a feasible alternative for routine quality control analysis, showing to be easy to implement, reliable, sensitive and with a low sample volume requirement to monitor Gly and MGly in environmental and biological matrices.

Patient surface radiation doses at two PET imaging facilities.

To develop a practical means of auditing the procedures and to optimize the administered radionuclide activity, patient surface radiation doses following the administration of 18FDG for PET imaging have been measured at breast and gonad locations at two PET facilities. Patient dosimetry was performed using LiF TLD-100 chips placed near the breasts and gonads for 2 h following tracer injection. Standard uptake values from the image-reconstruction algorithms of one PET camera were investigated in regions of interest in tomograms of the myocardium and liver with the aim of validating dosimetry at breasts. Mean doses measured on the patient's skin ranged between 3.3 and 6.1 microGy MBq(-1) at the gonads and between 3.9 and 6.4 microGy MBq(-1) at the breasts, noticeably lower than the calculations reported in the literature. These values show good concordance with the injected activities, although they are not proportional. The proportion of injected activity actually contributing to image production seems to decrease gradually as the injected activity increases. Conversely, for a given injected activity, breast and gonadal doses were found to be lower than the values expected from the numerical calculations reported in the literature, showing increasing discrepancies when the injected activity increased. Doses measured at the right breast were consistently higher than for the left, which is indicative of greater radiotracer absorption by the liver compared to the average absorption in the body.

In situ analysis of methylglyoxal metabolism in Saccharomyces cerevisiae.

Methylglyoxal metabolism was studied during Saccharomyces cerevisiae grown with D-glucose as the sole carbon and energy source. Using for the first time a specific assay for methylglyoxal in yeast, metabolic fluxes of its formation and D-lactate production were determined. D-Glucose consumption and ethanol production were determined during growth. Metabolic fluxes were also determined in situ, at the glycolytic triose phosphate levels and glyoxalase pathway. Maximum fluxes of ethanol production and glucose consumption correspond to maxima of methylglyoxal and D-lactate formation fluxes during growth. Methylglyoxal formation is quantitatively related to glycolysis, representing 0.3% of the total glycolytic flux in S. cerevisiae.

Preliminary safety evaluation of a cyclotron facility for positron emission tomography imaging.

This work describes the design characteristics of a medical imaging centre which uses positron emission tomography, with a cyclotron for fluorine-18 and nitrogen-13 production, and which has provided experimental information on operational data recorded by area dosimetry since 1995. Doses to radiopharmacy and medical staff have been measured both in normal work and in some handling incidents. Data on radiation levels in the installation have also been obtained and related to design details and shielding. Area dosimetry was carried out using a five-stationary detector network, with a sampling rate of 2 min(-1), and by thermoluminescent dosimetry (TLD). Staff were also monitored by TLD, using extra chips for finger dosimetry and to duplicate individual whole-body dosimetry in order to measure doses in certain single operations. For normal work, average whole-body doses to radiopharmacy staff were between 0.03 and 0.28 mSv/month, wrist doses were between 0.42 and 2.67 mSv/month, and finger doses were between 1.4 and 7.7 mSv/day for the left hand and 0.8 and 2.4 mSv/day for the right hand; such variation reflects the differing expertise of staff and the role played by optimisation. Finger doses between 16 and 131 mSv were measured in handling incidents, and finger doses of 20.2 and 20.7 mSv for the left hand and 22.0 and 22.3 mSv for the right hand were measured during handling of a syringe without shielding, containing 3 GBq. For medical staff, contributions to the whole-body dose of 2.0 and 1.9 microSv/procedure were measured for injection and placing the patient on the examination couch, respectively. Dose measurement on the middle finger of the right hand gives an average of 70 microSv during the injection. The provisions regarding the shielding design have proved to be adequate and effective during a 3-year operational period. Operational doses to medical staff are comparatively low, while radiopharmacy staff are the most exposed. The finger doses in these professionals may exceed the annual limit, unless operational restrictions in daily practice are adopted. On-line area dosimetry records based on dose rate probes have proved to be effective both for monitoring radiation levels during the operation and for detecting changes in the behaviour of the facility in the irradiation process.