Surveillance of Avian Influenza Virus in Aquatic Birds on the Brazilian Amazon Coast

EcoHealth - The occurrence of avian influenza viruses (AIV) has been extensively studied in aquatic birds in the Northern hemisphere; however, much less information is available for the South...     

Identification, tissue distribution and evaluation of brain neuropeptide Y gene expression in the Brazilian flounder Paralichthys orbignyanus

Neuropeptide Y (NPY) is one of the most potent stimulants of food intake in vertebrates, mammals and fish. However, the present knowledge about feeding behaviour in fish is still limited and based on studies in a few species. The Brazilian flounder Paralichthys orbignyanus is being considered for aquaculture, and it is important to understand the mechanisms regulating feeding in order to improve its performance in captivity. The objectives of this study were to clone NPY cDNA, evaluate the mRNA levels in different tissues of flounder, and also evaluate brain NPY expression to associate food intake with NPY expression levels. A 597 bp NPY cDNA was cloned from Brazilian flounder brain. NPY expression was detected in all the peripheral tissues analysed. No significant differences were observed in brain NPY gene expression over 24 h after food intake at a temperature of 15 ± 3°C. No correlation was observed among plasma glucose, total protein, cholesterol, triglycerides and NPY expression levels during this 24 h period. On the other hand, mRNA levels were increased after two weeks of fasting at elevated temperatures. Our results suggest that NPY mRNA levels in Brazilian flounder are affected by temperature.     

Sugar phosphorylation modulates ADP inhibition of maize mitochondrial hexokinase

The preference of maize ( Zea mays L.) mitochondrial hexokinase (EC 2.7.1.1.) for glucose and fructose and the ADP regulation were evaluated. The Michaelis-Menten constants (K_m) varied between 0.02 and 0.09 m M for glucose and from 2 to 6 m M for fructose as substrates. The value of V_max was five times higher in the presence of glucose as compared with fructose in membrane-bound enzyme preparations. It was shown that ADP produced from the reaction inhibits the hexokinase activity (K_i=20–50 μ M ). However, the inhibition was very specific for adenine nucleotide. Only a small inhibition was observed when 1 m M of UDP, CDP or GDP was included in the assay medium. Nevertheless, the ADP inhibition was observed only when glucose was phosphorylated. In assay conditions where fructose serves as substrate, the affinity for ADP decreased by 10-fold (K_i varied between 500 and 1  000 μ M ). These kinetics properties were also observed in partially purified soluble enzyme preparations. These data suggest that the type of hexose bound to the catalytic site modulates the ADP control of maize mitochondrial hexokinase.     

Correction to: Life cycle assessment of electricity generation: a review of the characteristics of existing literature

The International Journal of Life Cycle Assessment - The original version of this article unfortunately contained a mistake which was missed during typesetting. The figures of Graph 1 and...     

Membrane structure and interactions of a short Lycotoxin I analogue.

Lycotoxin I and Lycotoxin II are natural anti-microbial peptides that were identified in the venom of the Wolf Spider Lycosa carolinensis. These peptides were found to be potent growth inhibitors for bacteria (Escherichia coli) and yeast (Candida glabrata) at micromolar concentrations. Recently, shortened analogues of LycoI and LycoII have been reported to have decreased haemolytic effects. A shorter Lyco-I analogue studied, LycoI 1-15 (H-IWLTALKFLGKHAAK-NH2), was active only above 10 microM, but was also the least haemolytic. On the basis of these findings, we became interested in obtaining a deeper insight into the membrane activity of LycoI 1-15, as this peptide may represent the first major step for the future development of selective, i.e. non-haemolytic, Lycotoxin-based antibiotics. The interaction of this peptide with liposomes of different composition was studied by microcalorimetry [differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC)] and CD. The results obtained from the calorimetric and spectroscopic techniques were jointly discussed in an attempt to further understand the interaction of this peptide with model membranes.     

AtGRP3 Is Implicated in Root Size and Aluminum Response Pathways in Arabidopsis

AtGRP3 is a glycine-rich protein (GRP) from Arabidopsis thaliana shown to interact with the receptor-like kinase AtWAK1 in yeast, in vitro and in planta. In this work, phenotypic analyses using transgenic plants were performed in order to better characterize this GRP. Plants of two independent knockout alleles of AtGRP3 develop longer roots suggesting its involvement in root size determination. Confocal microscopy analysis showed an abnormal cell division and elongation in grp3-1 knockout mutants. Moreover, we also show that grp3-1 exhibits an enhanced Aluminum (Al) tolerance, a feature also described in AtWAK1 overexpressing plants. Together, these results implicate AtGRP3 function root size determination during development and in Al stress.