Effect of Organic Residues and Liming Materials on Metal Extraction from a Mining-Contaminated Soil

Incubation tests were used to assess the effectiveness of three different organic residues and three different liming materials, alone or in combination, in the remediation of a mine contaminated soil. The organic residues tested were sewage sludge from a municipal wastewater treatment plant (SS), compost from the organic fraction of unsorted municipal solid waste (MSWC), and garden waste compost (GWC), applied at 100 and 200 Mg ha^{? 1}. The liming materials tested were agriculture limestone (6.4 Mg ha^{? 1}), calcium oxide (3.7 Mg ha^{? 1}), and sugar beet sludge (12.2 Mg ha^{? 1}) from the sugar manufacturing process. The soil and mixtures of soil and amendments were adjusted to 70% of the maximum water holding capacity and incubated for 28 days in a controlled-temperature room at 20°C ± 1°C. At the end of the incubation, samples were analyzed for pH, electrical conductivity, organic matter content, CaCl₂-extractable, and' NH4Ac/HAc+ EDTA–extractable metal fractions (Cu, Zn, and Pb). Correlations among the variables and/or similarities among the treatments were identified by principal component analysis and hierarchical cluster analysis. The amendments tested decreased the CaCl₂-extractable Cu and Zn fractions, considered as mobile metal fractions, to below analytical detectable limits, providing organic matter to the soil with levels between 1% and 2% at the end of the experiment, significantly different relatively to the original soil. pH and electrical conductivity reached high values when using 200 Mg ha^{? 1} SS or 200 Mg ha^{? 1} MSWC, with any of the liming materials tested, making these application rates excessive for this particular situation. Furthermore, the treatments using MSWC increased the NH4Ac/HAc+ EDTA–extractable Cu, Pb, and Zn fractions, considered as mobilizable metal fractions, as did the 200 Mg ha^{? 1} SS for Pb and Zn. Considering the overall results, the compost made from garden waste decreased metal solubility in the soil and increased soil pH and organic matter content, without the addition of large amounts of soluble salts, and without increasing the mobilizable metal content. Of the organic materials tested, this was the only one that can be considered adequate for remediation of the contaminated soil under study, at the application rates tested.     

Evolution of the 28S ribosomal RNA gene in anurans: regions of variability and their phylogenetic implications

Fifteen restriction sites were mapped to the 28S ribosomal RNA gene of individuals representing 54 species of frogs, two species of salamanders, a caecilian, and a lungfish. Eight of these sites were present in all species examined, and two were found in all but one species. Alignment of these conserved restriction sites revealed, among anuran 28S rRNA genes, five regions of major length variation that correspond to four of 12 previously identified divergent domains of this gene. One of the divergent domains (DD8) consists of two regions of length variation separated by a short segment that is conserved at least throughout tetrapods. Most of the insertions, deletions, and restriction-site variations identified in the 28S gene will require sequence-level analysis for a detailed reconstruction of their history. However, an insertion in DD9 that is coextensive with frogs in the suborder Neobatrachia, a BstEII site that is limited to representatives of two leptodactylid subfamilies, and a deletion in DD10 that is found only in three ranoid genera are probably synapomorphies.      

Two new species of <Emphasis Type="Italic">Calathea</Emphasis> (<Emphasis Type="Italic">Marantaceae</Emphasis>) from South-eastern Brazil

Summary   Calathea dryadica and Calathea reginae are described, circumscribed and illustrated. These new species are probably endemic to the Atlantic Forest of Rio de Janeiro State in Southeast Brazil and are considered critically endangered because of the restricted geographic area of occurrence, sometimes enclosed by densely urbanised areas.     

Characterization of cross-bridge elasticity and kinetics of cross-bridge cycling during force development in single smooth muscle cells

Force development in smooth muscle, as in skeletal muscle, is believed to reflect recruitment of force-generating myosin cross-bridges. However, little is known about the events underlying cross-bridge recruitment as the muscle cell approaches peak isometric force and then enters a period of tension maintenance. In the present studies on single smooth muscle cells isolated from the toad (Bufo marinus) stomach muscularis, active muscle stiffness, calculated from the force response to small sinusoidal length changes (0.5% cell length, 250 Hz), was utilized to estimate the relative number of attached cross-bridges. By comparing stiffness during initial force development to stiffness during force redevelopment immediately after a quick release imposed at peak force, we propose that the instantaneous active stiffness of the cell reflects both a linearly elastic cross-bridge element having 1.5 times the compliance of the cross-bridge in frog skeletal muscle and a series elastic component having an exponential length-force relationship. At the onset of force development, the ratio of stiffness to force was 2.5 times greater than at peak isometric force. These data suggest that, upon activation, cross-bridges attach in at least two states (i.e., low-force-producing and high-force-producing) and redistribute to a steady state distribution at peak isometric force. The possibility that the cross-bridge cycling rate was modulated with time was also investigated by analyzing the time course of tension recovery to small, rapid step length changes (0.5% cell length in 2.5 ms) imposed during initial force development, at peak force, and after 15 s of tension maintenance. The rate of tension recovery slowed continuously throughout force development following activation and slowed further as force was maintained. Our results suggest that the kinetics of force production in smooth muscle may involve a redistribution of cross-bridge populations between two attached states and that the average cycling rate of these cross-bridges becomes slower with time during contraction.     

Effect of dexamethasone on human osteoblasts in culture: involvement of β1 integrin and integrin-linked kinase

Adhesive interactions play a critical role in cell biology, influencing vital processes from proliferation to cell death. Integrins regulate cell-ECM (extracellular matrix) adhesion and must associate with phosphorylating proteins such as ILK (integrin-linked kinase). Dysregulation of ILK expression is associated with anchorage-independent growth, cell survival and inhibition of apoptosis. Glucocorticoids influence differentiation and adhesion of osteoblasts and can affect bone protein synthesis. The objective of this study was to analyse the effect of DEX (dexamethasone) on the biology of osteoblasts, together with its influence on the expression of ILK and β1 integrin. For this, primary cultures of human osteoblasts were exposed to DEX at 10-9 M (physiological dose) and 10-6 M (pharmacological dose) for 24 and 48 h. Cell viability, apoptosis and cell adhesion were analysed, as well as protein expression of β1 integrin and ILK. It was observed that cell viability and adhesion were reduced in the cultures evaluated. In comparison with the control cultures, there was slightly less apoptosis in the cultures exposed to the physiological dose and considerably more apoptosis in those exposed to the pharmacological dose. In all treated cultures, protein expression of ILK was slightly higher than in the control cultures, whereas that of β1 integrin was significantly lower. Both proteins under study were co-localized at the cell periphery in all cultures. Our results suggest that DEX causes osteoblast anoikis, probably due to decreased β1 integrin expression, which might have had a direct influence upon ILK, reducing its activation and preventing it from playing its characteristic anti-apoptotic role.     

Traffic of Leukocytes and Cytokine Up-regulation in the Central Nervous System in a Murine Model of Neuroparacoccidioidomycosis

Background

Paracoccidioidomycosis is the most important systemic mycosis in South America. In the last decades, it was observed that central nervous system involvement is frequent, occurring in 12.5 % of the cases. The aim of this study was to report the early inflammatory changes associated with an experimental model of neuroparacoccidioidomycosis (NPCM).

Methods

C57BL/6 mice were infected by intracranial route with 10⁶ yeast cells of PB18 strain of Paracoccidioides brasiliensis. Leukocyte–endothelium interactions were assessed by intravital microscopy 1, 2, 4, and 8 weeks post-infection (p.i.). Chemokine/cytokine levels in the brain and histopathological changes were assessed 4 and 8 weeks p.i..

Results

Intravital microscopy analysis revealed a progressive increase in leukocyte recruitment in the vessels of pia mater with a peak 4 weeks p.i. The chemokine CXCL9 was increased at 4 and 8 weeks p.i., while CCL2, CCL3, and CCL5 were increased at 8 weeks p.i. Histopathological analysis revealed the infiltration of inflammatory cells and the development of progressive granulomatous meningoencephalitis. CCL3 levels correlated with clinical manifestations of disease, as measured by the SHIRPA battery.

Conclusions

The experimental model of NPCM showed increased leukocyte recruitment associated with increased expression of chemokines and nervous tissue inflammation which correlated with clinical manifestations of disease.     

Dihydroisocoumarins and phthalide from wood samples infested by fungi

Wood samples, infested by fungi during storage, were shown to contain, besides the known 5-methyl-mellein, additional (3R)-8-hydroxy-3-methyl-3,4-dihydroisocoumarins substituted by 7-methyl, 5-formyl, 5-carboxy, 5-hydroxy, 5-methoxy, 6-methoxy-5-methyl and 6,7-dimethoxy-5-methyl groups, as well as 6-formyl-7-hydroxy-5-methoxy-4-methylphthalide. Several 2-methylchromanones were synthesized in order to show that this class of compounds can be distinguished from 3-methyl-3,4-dihydroisocoumarins by MS.     

Contrasting Brood-Sex Ratio Flexibility in Two Opiine (Hymenoptera: Braconidae) Parasitoids of Tephritid (Diptera) Fruit Flies

Mass-rearing of fruit fly parasitoids for augmentative release would be more economical if production could be biased towards females. If sex ratios are ever to be manipulated under rearing conditions it is important to determine if, then understand why, sex ratio flexibility exists. Unequal brood-sex ratios are common in parasitic Hymenoptera and two reasons are generally advanced for such cases: 1) avoidance of Local Mate Competition (LMC) predicts that the number of females exploiting a host-patch can influence the optimal sex ratio of their offspring; and 2) one sex is more likely to develop under a particular set of physical/competitive conditions. We hypothesized that LMC is more often encountered in relatively uncommon species with coarse-grained distributions. As a result, isolated females of such species would be more likely to expect future LMC to be high and to bias offspring sex ratios towards females. We proposed that the opiine braconid Utetes anastrephae is such a coarse-grained species and compared its responses to differences to LMC (isolated females and those paired with a conspecific competitor) with those of another opiine, Diachasmimorpha longicaudata believed to have a finer-grained distribution. Adult sex ratios were mutable in D. longicaudata and U. anastrephae and, as predicted by avoidance of LMC, males were relatively more abundant among the paired females in both species. However, superparasitized hosts yielded relatively more daughters, perhaps because female larvae are superior intrinsic competitors. Contrary to prediction, there was no suggestion that U. anastrephae was more likely to than D. longicaudata to avoid LMC. While these results did not reveal any species differences in sex-allocation patterns or suggest any modifications to the present practice of fruit fly mass-rearing for augmentative release they did provide new information regarding U. anastrephae, a widespread natural enemy of Anastrepha spp. about which relatively little is known.