Functional characterization of the thi1 promoter region from Arabidopsis thaliana

The Arabidopsis thaliana THI1 protein is involved in thiamine biosynthesis and is targeted to both chloroplasts and mitochondria by N-terminal control regions. To investigate thi1 expression, a series of thi1 promoter deletions were fused to the beta-glucuronidase (GUS) reporter gene. Transgenic plants were generated and expression patterns obtained under different environmental conditions. The results show that expression derived from the thi1 promoter is detected early on during development and continues throughout the plant's life cycle. High levels of GUS expression are observed in both shoots and roots during vegetative growth although, in roots, expression is restricted to the vascular system. Deletion analysis of the thi1 promoter region identified a region that is responsive to light. The smallest fragment (designated Pthi322) encompasses 306 bp and possesses all the essential signals for tissue specificity, as well as responsiveness to stress conditions such as sugar deprivation, high salinity, and hypoxia.     

Ouabain-insensitive Na+-ATPase of proximal tubules is an effector for urodilatin and atrial natriuretic peptide

In the present paper we studied the effect of urodilatin and atrial natriuretic peptide (ANP) on the proximal tubule Na+-ATPase and (Na+K+)ATPase activities. Urodilatin and ANP inhibit the Na+-ATPase activity but not the (Na+K+)ATPase activity. Maximal effect was observed at a concentration of 10(-11) M for both peptides. In this condition, the enzyme activity decreases from 10.8 +/- 1.6 (control) to 5.7 +/- 0.9 or 6.1 +/- 0.7 nmol Pi mg(-1) min(-1) in the presence of urodilatin or ANP, respectively. This effect was completely reversed by 10(-6) M LY83583, a guanylyl cyclase inhibitor, and mimicked by 10 nM cGMP. Furthermore, both ANP and urodilatin increase cGMP production by 33% and 49%, respectively. This is the first demonstration that it was shown that urodilatin and ANP directly modulate primary active sodium transport in the proximal tubule. The data obtained indicate that this effect is mediated by the activation of the NPR-A/guanylate cyclase/cGMP pathway.     

The effect of Bulgarian propolis against Trypanosoma cruzi and during its interaction with host cells

Propolis has shown activity against pathogenic microorganisms that cause diseases in humans and animals. The ethanol (Et-Blg) and acetone (Ket-Blg) extracts from a Bulgarian propolis, with known chemical compositions, presented similar activity against tissue culture-derived amastigotes. The treatment of Trypanosoma cruzi-infected skeletal muscle cells with Et-Blg led to a decrease of infection and of the intracellular proliferation of amastigotes, while damage to the host cell was observed only at concentration 12.5 times higher than those affecting the parasite. Ultrastructural analysis of the effect of both extracts in epimastigotes revealed that the main targets were the mitochondrion and reservosomes. Et-Blg also affected the mitochondrion-kinetoplast complex in trypomastigotes, offering a potential target for chemotherapeutic agents.     

The essential fatty acid status in phenylketonuria patients under treatment

Phenylketonuric patients are on a special diet that lacks certain essential fatty acids. This study evaluates the essential fatty acid status of a group of phenylketonuric patients in the Netherlands undergoing dietary treatment. To this end, the essential fatty acid status of nine phenylketonuria patients was studied. On the basis of age and gender, two control subjects were selected for each patient. The essential fatty acid composition of duplicate food portions and the essential fatty acid status of plasma and erythrocytes were analyzed. Phenylketonuria subjects had a different essential fatty acid profile from their peers, especially concerning the n-3 fatty acids. N-6 and n-3 fatty long-chain polyenes were hardly consumed by phenylketonuria subjects, in contrast to the control subjects. Linoleic acid, on the other hand, was consumed in significantly higher amounts by phenylketonuria subjects and made up about 40% of their daily fat consumption. The essential fatty acid consumption pattern of the phenylketonuria subjects is mirrored by the essential fatty acid concentrations in blood. The essential fatty acid status of the phenylketonuric diet should be improved in order to prevent deficiency in n-3 fatty acids.     

Do the phenology and functional stem attributes of woody species allow for the identification of functional groups in the semiarid region of Brazil?

The phenology of tree species in environments that are subject to strong climatic seasonality is mainly determined by water availability, which may vary as a function of wood density. The relationship among phenology, water potential, wood density and the capacity of water storage in the stem were determined for woody species of caatinga vegetation (dry forest) in the semiarid region of NE Brazil. Leaf flush and fall, flowering and fruiting events were recorded over a 31-month period, and the water potential was measured over a two-year period. These data were related to precipitation, water availability in the soil and photoperiod. Seven deciduous species exhibited low wood density (DLWD,?<0.5?g?cm^?3), high capacity of water storage in the stem (until 250?% of the dry weight) and high water potential during the year, as opposed to 15 deciduous species that showed high wood density (DHWD,?≥0.5?g?cm^?3). Leaf flush, flowering and the fruiting of DHWD species were related to precipitation, whereas these phenological events occurred at the end of the dry season and/or the beginning of the rainy season for DLWD species and were related to the photoperiod. The two evergreen species showed variations of water potential that were intermediate between those of DHWD and DLWD deciduous species, leaf flush during the dry season and flowering at the end of dry season. These results suggest the existence of three functional groups: evergreen species, DHWD deciduous species and DLWD deciduous species.     

Bone formation rather than inflammation reflects Ankylosing Spondylitis activity on PET-CT: a pilot study

Introduction

Positron Emission Tomography - Computer Tomography (PET-CT) is an interesting imaging technique to visualize Ankylosing Spondylitis (AS) activity using specific PET tracers. Previous studies have shown that the PET tracers [¹⁸F]FDG and [¹¹C](R)PK11195 can target inflammation (synovitis) in rheumatoid arthritis (RA) and may therefore be useful in AS. Another interesting tracer for AS is [¹⁸F]Fluoride, which targets bone formation. In a pilot setting, the potential of PET-CT in imaging AS activity was tested using different tracers, with Magnetic Resonance Imaging (MRI) and conventional radiographs as reference.

Methods

In a stepwise approach different PET tracers were investigated. First, whole body [¹⁸F]FDG and [¹¹C](R)PK11195 PET-CT scans were obtained of ten AS patients fulfilling the modified New York criteria. According to the BASDAI five of these patients had low and five had high disease activity. Secondly, an extra PET-CT scan using [¹⁸F]Fluoride was made of two additional AS patients with high disease activity. MRI scans of the total spine and sacroiliac joints were performed, and conventional radiographs of the total spine and sacroiliac joints were available for all patients. Scans and radiographs were visually scored by two observers blinded for clinical data.

Results

No increased [¹⁸F]FDG and [¹¹C](R)PK11195 uptake was noticed on PET-CT scans of the first 10 patients. In contrast, MRI demonstrated a total of five bone edema lesions in three out of 10 patients. In the two additional AS patients scanned with [¹⁸F]Fluoride PET-CT, [¹⁸F]Fluoride depicted 17 regions with increased uptake in both vertebral column and sacroiliac joints. In contrast, [¹⁸F]FDG depicted only three lesions, with an uptake of five times lower compared to [¹⁸F]Fluoride, and again no [¹¹C](R)PK11195 positive lesions were found. In these two patients, MRI detected nine lesions and six out of nine matched with the anatomical position of [¹⁸F]Fluoride uptake. Conventional radiographs showed structural bony changes in 11 out of 17 [¹⁸F]Fluoride PET positive lesions.

Conclusions

Our PET-CT data suggest that AS activity is reflected by bone activity (formation) rather than inflammation. The results also show the potential value of PET-CT for imaging AS activity using the bone tracer [¹⁸F]Fluoride. In contrast to active RA, inflammation tracers [¹⁸F]FDG and [¹¹C](R)PK11195 appeared to be less useful for AS imaging.     

Factors affecting seasonal variations in demersal fish assemblages at an ecocline in a tropical–subtropical estuary

Seasonal changes of fish species composition in terms of biomass, density and number of species in three areas of the main channel of the Paranaguá Estuary (axis east–west) are described in relation to seasonal fluctuations in salinity, water temperature and dissolved oxygen in the main channel. Two hundred and thirty‐four samples were collected monthly, between July 2000 and June 2001, in the main channel. Seventy‐nine species of 29 families were captured with a total estimated mean density and biomass of 1513 individuals ha^?1 and 34 kg ha^?1, respectively. The number of species and total mean density differed significantly among areas and seasons, but the total mean biomass differed only significantly throughout the ecocline (areas) of the Paranaguá Estuary. For the most abundant species, the mean densities of Stellifer rastrifer, Aspistor luniscutis, Menticirrhus americanus, Sphoeroides testudineus, Cynoscion leiarchus and Symphurus tesselatus (with the exception of Cathorops spixii and Genidens genidens) differed significantly among seasons. The mean biomass of these species, with the exception of G. genidens, S. rastrifer, A. luniscutis and S. testudineus, also differed significantly for the factor seasons. Area was a significant factor for the eight most abundant species (density and biomass), except S. testudineus (density), G. genidens, C. leiarchus and S. tesselatus (biomass). The season v. area interaction term was significant for C. leiarchus (density). Most of these differences occurred during the rainy season when fishes concentrated principally in the middle of the estuary, where the salinity remained stable. It is suggested that the salinity stability in the middle of the estuary is the main reason why the most estuarine resident fish species move downstream and remain there, regardless of the increased freshwater runoff. Moreover, canonical correspondent analysis output detected that during the late rainy season, the variable dissolved oxygen (P < 0·01) was the most important environmental variable, responsible for structuring patterns of fishes assemblages in the west–east axis of Paranaguá Estuary. During the end of the dry season, both salinity (P < 0·01) and dissolved oxygen (P < 0·05) were responsible for this ecological feature in the estuary. Finally, it was possible to detect that juveniles and adults of some important species respond differently to seasonal fluctuations of the ecocline‐determining environmental factors. This behaviour is suggested as a strategy to avoid competition and predation during the rainy season in the middle estuary. The Paranaguá Estuary did not fit with the pre‐existing models described in the tropical and subtropical estuarine fish literature since its main channel fish assemblages remained within its bounds even during the rainy season.     

Effects of immature cashew nut-shell liquid (Anacardium occidentale) against oxidative damage in Saccharomyces cerevisiae and inhibition of acetylcholinesterase activity

The cashew tree (Anacardium occidentale) represents one of the major cheapest sources of non-isoprenoid phenolic lipids, which have a variety of biological properties: they can act as molluscicides, insecticides, fungicides, have anti-termite properties, have medicinal applications, and demonstrate antioxidant activity in vitro. Immature cashew nut-shell liquid (iCNSL) is a unique natural source of unsaturated long-chain phenols. Their use has stimulated much research in order to prepare drug analogues for application in several fields. The objective of the present study was to determine whether iCNSL has antioxidant properties when used in strains of the yeast Saccharomyces cerevisiae and to measure the inhibitory activity of acetylcholinesterase. The constituents were identified using thin-layer chromatography, gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy, and (1)H and (13)C nuclear magnetic resonance. The iCNSL contains anacardic acid, cardanol, cardol, and 2-methyl cardol. Immature cashew nut oil contains triacylglycerols, fatty acids, alkyl-substituted phenols, and cholesterol. The main constituents of the free fatty acids are palmitic (C(16:0)) and oleic acid (C(18:1)). iCNSL has excellent protective activities in strains of S. cerevisiae against oxidative damage induced by hydrogen peroxide and inhibits acetylcholinesterase activity. iCNSL may have an important role in protecting DNA against damage induced by reactive oxygen species, as well as hydrogen peroxide, generated by intra- and extracellular mechanisms.     

Comet assay to determine DNA damage induced by food deprivation in rats

The aim of this work was to evaluate, by comet assay, the possible inducing of DNA lesions in peripheral blood mononuclear cells of rats subjected to acute or chronic food deprivation. Wistar male rats were subjected to 72 h of partial (50%), or total acute food deprivation, and then allowed to recover for different time periods (24, 48 and 72 h). In other experiments, comet scores were determined in peripheral blood mononuclear cells of rats subjected to chronic food deprivation (25% and 50%) for 50 days. Blood aliquots were obtained before, during and after food deprivation. Comet assay was carried out, the comet units photographed and scored (class 0 up to 3). Acute and chronic food-deprived rats presented peripheral blood mononuclear cells with DNA lesions (comet classes 1, 2 and 3) and a significant increase (p<0.05) in the number of comet units compared with its basal level. The increase was proportional to acute food deprivation time, but after being taken off, it progressively returned to basal level after 48 h (partial group) or 72 h (total group). Chronic food-deprived rats presented a progressive increase of comet score up to 5 days, and a decrease thereafter to reach a basal level. Possible mechanisms of DNA lesions are discussed.