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211.
Heparan sulfate (HS) proteoglycans modulate the biological activity of a number of growth factors in development, homeostasis, and cancer. Specific modifications of HS chains by HS biosynthetic enzymes have been implicated in growth factor signaling in multiple aspects of organogenesis. Although the role of HS 6-O-sulfotransferases has been described in processes such as trachea formation in Drosophila and vasculogenesis in zebrafish, little is known about how HS 6-O-sulfotransferases (Hs6st1-3 in mice) influence mouse development. To address this issue, we generated a conditionally mutant Hs6st1 mouse line and then generated mice with systemic inactivation of Hs6st1. Hs6st1-null pups were viable and grossly normal at birth. The lack of obvious abnormalities in lung, liver, and kidney, which express high levels of Hs6st1 during development, suggests that at least during embryonic life, the loss of Hs6st1 function may be compensated for by mechanisms involving other HS modifying enzymes. During early adulthood, however, Hs6st1-null mice failed to thrive and exhibited growth retardation, body weight loss, enlargement of airspaces in the lung and, in some cases, lethality. Our results suggest a potentially critical role for HS 6-O sulfation by Hs6st1 in postnatal processes. 相似文献
212.
Marengo JA Nobre CA Tomasella J Cardoso MF Oyama MD 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2008,363(1498):1773-1778
In 2005, southwestern Amazonia experienced the effects of an intense drought that affected life and biodiversity. Several major tributaries as well as parts of the main river itself contained only a fraction of their normal volumes of water, and lakes were drying up. The consequences for local people, animals and the forest itself are impossible to estimate now, but they are likely to be serious. The analyses indicate that the drought was manifested as weak peak river season during autumn to winter as a consequence of a weak summertime season in southwestern Amazonia; the winter season was also accompanied by rainfall that sometimes reached 25% of the climatic value, being anomalously warm and dry and helping in the propagation of fires. Analyses of climatic and hydrological records in Amazonia suggest a broad consensus that the 2005 drought was linked not to El Niño as with most previous droughts in the Amazon, but to warming sea surface temperatures in the tropical North Atlantic Ocean. 相似文献
213.
Discrimination of bile acids by the rainbow trout olfactory system: evidence as potential pheromone 总被引:2,自引:0,他引:2
Electro-olfactogram recording was used to determine whether the olfactory epithelium of adult rainbow trout is specifically sensitive to bile acids, some of which have been hypothesized to function as pheromones. Of 38 bile acids that had been pre-screened for olfactory activity, 6 were selected. The rainbow trout-specific bile acids, taurocholic acid (TCA), and taurolithocholic acid 3-sulfate (TLS) were the most potent compounds tested. TLS had a distinctive dose-response curve. Cross-adaptation experiments demonstrated that sensitivity to bile acids is attributable to at least 3 independent classes of olfactory receptor sites. Our data suggest that bile acids are discriminated by olfaction in rainbow trout, supporting the possibility that these compounds function as pheromones. 相似文献
214.
A hierarchical animal model was developed for inference on genetic merit of livestock with uncertain paternity. Fully conditional posterior distributions for fixed and genetic effects, variance components, sire assignments and their probabilities are derived to facilitate a Bayesian inference strategy using MCMC methods. We compared this model to a model based on the Henderson average numerator relationship (ANRM) in a simulation study with 10 replicated datasets generated for each of two traits. Trait 1 had a medium heritability (h2) for each of direct and maternal genetic effects whereas Trait 2 had a high h2 attributable only to direct effects. The average posterior probabilities inferred on the true sire were between 1 and 10% larger than the corresponding priors (the inverse of the number of candidate sires in a mating pasture) for Trait 1 and between 4 and 13% larger than the corresponding priors for Trait 2. The predicted additive and maternal genetic effects were very similar using both models; however, model choice criteria (Pseudo Bayes Factor and Deviance Information Criterion) decisively favored the proposed hierarchical model over the ANRM model. 相似文献
215.
The Mondego estuary (Portugal) has suffered severe ecological stress over the last two decades, as manifested in the replacement
of seagrasses by opportunistic macroalgae, degradation of water quality and increased turbidity. A restoration plan was implemented
in 1998, which aimed to reverse the eutrophication effects, and especially to restore the original natural seagrass (Zostera noltii) community. This article explores the long-term changes in Ampithoe valida and Melita palmata (Amphipoda) populations in response to eutrophication (with consequent seagrass loss and macroalgal proliferation) and to
the subsequent restoration plan (with progressive seagrass recovery and macroalgal biomass decline). Until the early 1990s,
high densities of A. valida and M. palmata were recorded in the Mondego estuary, especially during the occurrence of the macroalgal bloom and during all the periods
in which green macroalgae were available. After the implementation of the restoration plan, species abundance, biomass and
production levels decreased considerably due to the progressive decline of green macroalgae. This implied the virtual disappearance
of the amphipod population, mainly A. valida. Distinct behaviours displayed by the two species could be related to different food strategies and habitat preferences.
Ampithoe valida showed feeding preferences for ephemeral softer, filamentous or bladed algae (e.g. Ulva sp.) due to its high caloric content, using the Z. noltii bed only as a habitat for protection against predators or shelter from wave action. On the other hand, M. palmata did not suffer a strong decline in its population density, biomass and production, which may indicate that this species is
probably not a primary consumer of green macroalgae and may readily shift to alternative ecological niches.
Handling editor: P. Viaroli 相似文献
216.
Site-specific chlorophyll reference conditions for lakes in Northern and Western Europe 总被引:1,自引:1,他引:0
Laurence Carvalho Angelo G. Solimini Geoff Phillips Olli-Pekka Pietiläinen Jannicke Moe Ana Cristina Cardoso Anne Lyche Solheim Ingmar Ott Martin Søndergaard Gianni Tartari Seppo Rekolainen 《Hydrobiologia》2009,633(1):59-66
The Water Framework Directive (WFD) requires EU Member States to assess the “ecological status” of surface waters. As a component of ecological status, many European countries are developing a classification scheme for chlorophyll concentrations as a measure of phytoplankton biomass. The chlorophyll classification must be based on the degree of divergence of a water body from an appropriate baseline or ‘reference condition’. This article describes the development of a series of regression models for predicting reference chlorophyll concentrations on a site-specific basis. For model development, a large dataset of European lakes considered to be in reference condition, 466 lakes in total, was assembled. Data were included from 12 European countries, but lakes from Northern and Western Europe dominated and made up 92% of all reference lakes. Data have been collated on chlorophyll concentration, altitude, mean depth, alkalinity, humic type, surface area and geographical region. Regression models were developed for estimating site-specific reference chlorophyll concentrations from significant predictor ‘typology’ variables. Reference chlorophyll concentrations were found to vary along a number of environmental gradients. Concentrations increased with colour and alkalinity and decreased with lake depth and altitude. Forward selection was used to identify independent explanatory variables in regression models for predicting site-specific reference chlorophyll concentrations. Depth was selected as an explanatory variable in all models. Alkalinity was included in models for low colour and humic lakes and altitude was included in models for low colour and very humic lakes. Uncertainty in the models was quite high and arises from errors in the data used to develop the models (including natural temporal and spatial variability in data) and also from additional explanatory variables not considered in the models, particularly nutrient concentrations, retention time and grazing. Despite these uncertainties, site-specific reference conditions are still recommended in preference to type-specific reference conditions, as they use the individual characteristics of a site known to influence phytoplankton biomass, rather than adopt standards set to generally represent a large population of lakes of a particular type. For this reason, site-specific reference conditions should result in reduced error in ecological status classifications, particularly for lakes close to typology boundaries. 相似文献
217.
C. M. Patreze E. N. De Paulo A. P. Martinelli E. J. B. Cardoso S. M. Tsai 《Symbiosis (Philadelphia, Pa.)》2009,48(1-3):164-172
The Fungal Ribosomallntergenic Spacer Analysis (F-RlSA) was used to characterize soil fungal communities from three Cecosystems ofAraucaria angustifolia from Brazil: a native forest and two replanted forest ecosystems, one of them with a past history of wildfire. The arbuscular mycorrhizal fungi (AMF) infection was evaluated inAraucaria roots of 18-monthold axenic plants previously inoculated with soils collected from those areas in a greenhouse experiment. The principal componentanalysis of F-RISA profiles showed different soil fungal community betweenthe three studied areas. Sixty three percent of F-RISA fragments amplified in the soil and the substrate samples presented lengths between 500 and 700 bp. The number of Operational Taxonomic Units (OTUs) was 34 for soil and 38 for substrate, however, more fragments were detected in soil (214) than in substrate (163). Anin silico F-RISA analysis to compare our data with ITSI-5.8S-ITS2 sequences from NCBI database showed the presence of Ascomycota, Basidiomycota and Glomeromycota among the soil and substrate fungal communities. AMF infection was higher in plants inoculated with soil from the native forest and the replanted forest with wildfire, both presenting similar chemical characteristics but with different disturbance levels. These results indicate that soil chemical composition may influence the soil fungal community structures rather than the anthropogenicor fire disturbances. 相似文献
218.
Fabrízio Siqueira Boniolo Raphael Cardoso Rodrigues Edson Oliveira Delatorre Mauricio Moura da Silveira Victor Martín Quintana Flores Marília Amorim Berbert-Molina 《Current microbiology》2009,59(6):593-599
In this study, the effect of glycine betaine as osmoprotectant compound for Gluconacetobacter diazotrophicus PAL5 was evaluated by kinetic growth parameters. Batch fermentation assays were performed employing media supplemented with
different sodium chloride concentrations to simulate saline stress conditions. Salt concentrations of 50–300 mM led to decreased
cell concentrations, while the maximum specific growth rates and cell productivities were reduced at concentrations above
100-mM NaCl. Salt inhibition was mainly observed in media with 200- and 300-mM NaCl, in which drastic changes in cell morphology
were also noted. The addition of glycine betaine to the media showed to be efficient to counteract the salt inhibitory effect
by increasing some fermentation parameters. However, the osmoprotectant was not able to revert the polymorphism promoted by
higher salt concentrations. 相似文献
219.
Amanda Ferreira da Silva Mendes Luciana Cardoso Cidade Maria Luiza Peixoto de Oliveira Wagner Campos Otoni Walter Dos Santos Soares-Filho Marcio Gilberto Cardoso Costa 《Plant Cell, Tissue and Organ Culture》2009,97(3):331-336
Identification of beta-lactam antibiotics that have negligible effects on plant regeneration is a critical step towards the
establishment of a reliable Agrobacterium-mediated transformation protocol for perennial trees. In the present report, we have evaluated the effects of the novel beta-lactam
antibiotics meropenem and timentin on plant regeneration of a perennial woody fruit plant, Citrus sinensis, in comparison with the commonly used beta-lactam cefotaxime. It was observed that, in contrast to cefotaxime, meropenem
and timentin had a positive or no detrimental effect on the shoot regeneration from epicotyl explants. Residual effects of
the beta-lactams from shoot regeneration medium also affected the subsequent ability of the roots to elongate. The addition
of meropenem and/or timentin in the rooting medium mostly improved or did not affect the rooting ability of the adventitious
shoots. These data indicated that meropenem and timentin can positively replace cefotaxime in Agrobacterium-mediated transformation of C. sinensis. 相似文献
220.
P. A. Vieira S. Faria R. B. Vieira F. P. De França V. L. Cardoso 《World journal of microbiology & biotechnology》2009,25(3):427-438
In order to optimize and evaluate the influence of nitrogen, phosphorus, and inoculum concentrations on the biodegradation
of hydrocarbon contaminated effluents, experiments based on central composite design (CCD) method were carried out for 3 days,
employing C1 mixed culture and intermittent aeration. The independent variables were nitrogen concentration (X
1), phosphorus concentration (X
2), and inoculum concentration (X
3) and the removal of total petroleum hydrocarbons (TPH) was the dependent variable. The optimized nutrients ratio (C:N:P = 100:20:2.7)
and inoculum concentration (1.32 g/l) provided TPH removal of 71.8% after processing for three days. Analysis using gas chromatography
identified five hydrocarbons classes: paraffins, isoparaffins, olefins, naphthenics, and aromatics. The naphthenic compounds
did not degrade as readily as the other hydrocarbons that were identified. The following degradation percentages were obtained:
87.1% for the paraffins, 77.7% for the isoparaffins, 78.6% for the olefins, 38.4% for the naphthenics, and 71.7% for the aromatics. 相似文献