Population growth and development of two species of Cladocera, Moina micrura and Diaphanosoma birgei, in laboratory

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Application of X-ray technique in nondestructive evaluation of eucalypt wood

X-rays were initially used for the inspection of special-purpose wood pieces for quantitative evaluation properties of different species. X-ray densitometry has had its use expanded ill dendroclimatology of Picea engelmannii trees. Subsequent laboratories developed applications of X-ray densitometry for environmental, wood science and technology, and related areas. This paper describes the basic methodology of X-ray densitometry applied to the eucalypt wood analysis, as well its presenting the results of applications in three areas: (i) evaluation of wood biodegradation by white rot fungi, (ii) detection of sapwood and heartwood, and (iii) determination of the effect of management oil wood properties. The wood decayed by white rot fungi was detected by X-ray densitometry with it decreasing wood density due to the biodegradation of cell wall components. The sapwood and heartwood of eucalypts were separated in response to the attenuation of X-rays, reflected by the wood anatomical structure and chemical composition. Also, Ill eucalypt trees after the application of irrigation and i characteristic wood density profiles were detected. Ill addition, the significant potential of X-ray densitometry for eucalypt wood research and analysis is discussed.

A comparison of the wood anatomy of 11 species from two cerrado habitats (cerrado s.s. and adjacent gallery forest)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Femur Mineral Density of Broilers with Femoral Degeneration Fed High Nutritional Density Diets

A study was carried out in the experimental facilities of FMVZ/UNESP-Botucatu, with the aim of following-up the development and the incidence of femoral degeneration (FD). A total of 305 one-day-old male broilers were housed in six pens of 5m(2) each. A completely randomized experimental design, with 3 treatments (T1-traditional nutritional density diet; T2-high nutritional density diet) of 3 replicates each was applied. Femoral head of the broilers were submitted to gross examination at 0, 7, 14, 21, 28, 35, and 42 days of aged. At 42 days of age, 60 birds (30 per treatment) were submitted to the Veterinary Hospital of FMVZ to determine bone mineral density by radiography. Birds were then sacrificed for gross examination of the legs, and FD scoring. Five legs per treatment within each FD score were submitted to computed tomography for femur head integrity and bone mineral density. Treatments did not influence FD incidence, and the first gross FD lesions appeared when birds were 28 days old. It was concluded that radiographic optical densitometry and computed tomography are efficient methods to evaluate femoral degeneration, and both techniques expressed the same profile. In addition, using radiographic optical densitometry and computed tomography, these results also allowed us to establish bone mineral density value ranges within each gross FD score. These finding may provide an excellent non-invasive tool to describe femoral degeneration.

Influence of cage fish farming on the diet of dominant fish species of a Brazilian reservoir (Tiete River, High Parana River basin)

The cage farming of aquatic organisms was initiated 50 years ago, and was introduced to Brazil in the 1990's. In these systems, there is an input of organic matter from ration that is not totally used by the cage fishes, becoming available for the organisms of adjacent biota, including fish fauna. The aim of this work is to evaluate the interference in the diet of three dominant fish species (Plagioscion squamosissimus Heckel, 1840, Astyanax altiparanae Garutti and Britski, 2000 and Metynnis maculatus Kner, 1858) associated with ish cage farming. For determination of the diet, the Alimentary Index (AI) was used. In both stretches (around cage farm and control), P. squamosissimus selected aquatic insects, while A. altiparanae preferred terrestrial insects and M. maculatus eats ration remains. Diferences in abundance of these feeding resources found of the stomach content were observed among the two stretches. Thus, the small alterations in the diets of P. squamosissimus and A. altiparanae, indicate that cage farming can change the diet of resident species in reservoirs. This practice also influences the population structure of fish species, since higher middle standard lengths were found in A. altiparanae and P. squamosissimus populations resident around cage farms, in relation to the control stretch.

Influence of the mineral content of the seston on tropical cladocerans of a marginal lake.

Bioassays were carried out seasonally to evaluate individual growth and reproduction of cladocerans, from a marginal lake, with the addition of nitrogen (N), phosphorus (P), and both N and P to natural seston; Methods: Cohorts originated from cultivated females were submitted to the following treatments: 1) lake seston, 2) lake seston + P, 3) lake seston + N, and 4) lake seston + NP; Results: The sestonic C:P and C:N molar ratios were always high and limiting, according to threshold ratios estimated for temperate lakes. P addition to seston enhanced the growth rates of one species, D. birgei. A significant higher growth rate of B. longirostris was found in the seston enriched with N compared to natural seston, as well as a higher fecundity of M. minuta. The fecundity of D. birgei was significantly higher in the seston enriched with both N and P. C, N, and P body content of cladocerans was similar to that of temperate counterparts; Conclusion: Energy limitation related to carbon content or food quality seems to be most important in controlling cladocerans' populations in the lake than food mineral content.

Photosynthetic characteristics of a tropical population of Nitella cernua (Characeae, Chlorophyta)

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

Temporal dynamics of two species of Chaetophoraceae (Chlorophyta) in tropical streams of São Paulo State, Southeastern Brazil

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

High current-density anodic electro-dissolution in flow-injection systems for the determination of aluminium, copper and zinc in non-ferroalloys by flame atomic absorption spectrometry

An automatic Procedure with a high current-density anodic electrodissolution unit (HDAE) is proposed for the determination of aluminium, copper and zinc in non-ferroalloys by flame atonic absorption spectrometry, based on the direct solid analysis. It consists of solenoid valve-based commutation in a flow-injection system for on-line sample electro-dissolution and calibration with one multi-element standard, an electrolytic cell equipped with two electrodes (a silver needle acts as cathode, and sample as anode), and an intelligent unit. The latter is assembled in a PC-compatible microcomputer for instrument control, and far data acquisition and processing. General management of the process is achieved by use of software written in Pascal. Electrolyte compositions, flow rates, commutation times, applied current and electrolysis time mere investigated. A 0.5 mol l(-1) HNO3 solution was elected as electrolyte and 300 A/cm(2) as the continuous current pulse. The performance of the proposed system was evaluated by analysing aluminium in Al-allay samples, and copper/zinc in brass and bronze samples, respectively. The system handles about 50 samples per hour. Results are precise (R.S.D < 2%) and in agreement with those obtained by ICP-AES and spectrophotometry at a 95% confidence level.

Effects of mutations in acetate metabolism on high-cell-density growth of Escherichia coli

To study the role played by acetate metabolism during high-cell-density growth of Escherichia coli cells, we constructed isogenic null mutants of strain W3100 deficient for several genes involved either in acetate metabolism or the transition to stationary phase. We grew these strains under identical fed-batch conditions to the highest cell densities achievable in 8 h using a predictive-plus-feedback-controlled computer algorithm that maintained glucose at a set-point of 0.5 g/l, as previously described. Wild-type strains, as well as mutants lacking the sigma(s) subunit of RNA polymerase (rpoS), grew reproducibly to high cell densities (44-50 g/l dry cell weights, DCWs). In contrast, a strain lacking acetate kinase (ackA) failed to reach densities greater than 8 g/l. Strains lacking other acetate metabolism genes (pta, acs, poxB, iciR, and fadR) achieved only medium cell densities (15-21 g/l DCWs). Complementation of either the acs or the ackA mutant restored wild-type high-cell-density growth, on a dry weight basis, poxB and fadR strains produced approximately threefold more acetate than did the wild-type strain. In contrast, the pta, acs, or rpoS strains produced significantly less acetate per cell dry weight than did the wild-type strain. Our results show that acetate metabolism plays a critical role during growth of E. coli cultures to high cell densities. They also demonstrate that cells do not require the sigma(s) regulon to grow to high cell densities, at least not under the conditions tested.

Kinetic evaluation of the pyrolysis of high density polyethylene over H-AlMCM-41 material

The AlMCM-41 material with Si/Al=50 was synthesized by hydrothermal method, using cethyltrimethylammonium as template. The protonic H-AlMCM-41 acid form was obtained by ion exchange with ammonium chloride solution and subsequent calcination. The characterization of the material by several techniques showed that a good-quality MCM-41 material was obtained. High-density polyethylene (HDPE) has been submitted to thermal degradation alone, and in presence of the exchanged H-AlMCM-41 catalyst at a concentration of 1: 1 in mass (H-AlMCM-41/HDPE). The reactor was connected on line to a gas chromatograph connected to a mass spectrometer. This process was evaluated by thermogravimetry (TG), from 350 to 600degreesC, under helium dynamic atmosphere, with heating rates of 5.0; 10.0 and 20.0 degreesC/min. From TG curves, the activation energy, calculated using a multiple heating rate integral kinetic method, decreased from 225.5 KJ.mol(-1), for the pure polymer (HDPE), to 184.7 KJ.mol(-1), in the presence of the catalyst (H-AlMCM-41/HDPE).

Simultaneous determination of furanocoumarins in infusions and decoctions from Carapia (Dorstenia species) by high-performance liquid chromatography

The use of furanocoumarins, which are photosensitizing compounds, combined with exposure to UV-A radiation is a common treatment for vitiligo, psoriasis, and a number of other skin diseases. Although furanocoumarins plus UV-A treatment is highly effective, several studies have shown that exposure to high doses increases the risk to development of cutaneus carcinoma. Several Dorstenia species are used in folk medicine, mainly against skin diseases, because of the presence of biologically active compounds. We present here analysis of the chemical composition of furanocoumarins from infusion and decoction of Carapia (Dorstenia species), which is used in Brazil against several diseases. We have employed high-performance liquid chromatography (HPLC) procedures for the quantitative determination of psoralen, bergapten, and isopimpinellin. The contents of furanocoumarins revealed an insignificant difference between infusion and decoction. Dorstenia tubicina and D. asaroides contained psoralen and bergapten only in the rhizomes, whereas D. vitifolia shows solely isopimpinellin in both rhizomes and aerial parts.