Cardiomyocyte dysfunction during the chronic phase of Chagas disease

Chagas disease, which is caused by the parasite Trypanosoma cruzi, is an important cause of heart failure. We investigated modifications in the cellular electrophysiological and calcium-handling characteristics of an infected mouse heart during the chronic phase of the disease. The patch-clamp technique was used to record action potentials (APs) and L-type Ca²⁺ and transient outward K⁺ currents. [Ca²⁺]_i changes were determined using confocal microscopy. Infected ventricular cells showed prolonged APs, reduced transient outward K⁺ and L-type Ca²⁺ currents and reduced Ca²⁺ release from the sarcoplasmic reticulum. Thus, the chronic phase of Chagas disease is characterised by cardiomyocyte dysfunction, which could lead to heart failure.     

Serial measurement of the circulating levels of tumour necrosis factor and its soluble receptors 1 and 2 for monitoring leprosy patients during multidrug treatment

Leprosy is an infectious and contagious spectral disease accompanied by a series of immunological events triggered by the host response to the aetiologic agent, Mycobacterium leprae . The induction and maintenance of the immune/inflammatory response in leprosy are linked to multiple cell interactions and soluble factors, primarily through the action of cytokines. The purpose of the present study was to evaluate the serum levels of tumour necrosis factor (TNF)-α and its soluble receptors (sTNF-R1 and sTNF-R2) in leprosy patients at different stages of multidrug treatment (MDT) in comparison with non-infected individuals and to determine their role as putative biomarkers of the severity of leprosy or the treatment response. ELISA was used to measure the levels of these molecules in 30 healthy controls and 37 leprosy patients at the time of diagnosis and during and after MDT. Our results showed increases in the serum levels of TNF-α and sTNF-R2 in infected individuals in comparison with controls. The levels of TNF-α, but not sTNF-R2, decreased with treatment. The current results corroborate previous reports of elevated serum levels of TNF-α in leprosy and suggest a role for sTNF-R2 in the control of this cytokine during MDT.     

Metabolism of biodiesel-derived glycerol in probiotic Lactobacillus strains

Three probiotic Lactobacillus strains, Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus delbrueckii, were tested for their ability to assimilate and metabolize glycerol. Biodiesel-derived glycerol was used as the main carbon and energy source in batch microaerobic growth. Here, we show that the tested strains were able to assimilate glycerol, consuming between 38 and 48 % in approximately 24 h. L. acidophilus and L. delbrueckii showed a similar growth, higher than L. plantarum. The highest biomass reached was 2.11 g?L^?1 for L. acidophilus, with a cell mass yield (Y _X/S) of 0.37 g?g^?1. L. delbrueckii and L. plantarum reached a biomass of 2.06 and 1.36 g?L^?1. All strains catabolize glycerol mainly through glycerol kinase (EC 2.7.1.30). For these lactobacillus species, kinetic parameters for glycerol kinase showed Michaelis–Menten constant (K _m) ranging from 1.2 to 3.8 mM. The specific activities for glycerol kinase in these strains were in the range of 0.18 to 0.58 U?mg?protein^?1, with L. acidophilus ATCC 4356 showing the maximum specific activity after 24 h of cultivation. Glycerol dehydrogenase activity was also detected in all strains studied but only for the reduction of glyceraldehyde with NADPH (K _m for DL-glyceraldehyde ranging from 12.8 to 32.3 mM). This enzyme shows a very low oxidative activity with glycerol and NADP⁺ and, most likely, under physiological conditions, the oxidative reaction does not occur, supporting the assumption that the main metabolic flux concerning glycerol metabolism is through the glycerol kinase pathway.     

Detection of Leishmania infantum in animals and their ectoparasites by conventional PCR and real time PCR

Visceral leishmaniosis (VL) is a parasitic disease caused by Leishmania infantum, which is primarily transmitted by phlebotomine sandflies. However, there has been much speculation on the role of other arthropods in the transmission of VL. Thus, the aim of this study was to assess the presence of L. infantum in cats, dogs and their ectoparasites in a VL-endemic area in northeastern Brazil. DNA was extracted from blood samples and ectoparasites, tested by conventional PCR (cPCR) and quantitative real time PCR (qPCR) targeting the L. infantum kinetoplast DNA. A total of 280 blood samples (from five cats and 275 dogs) and 117 ectoparasites from dogs were collected. Animals were apparently healthy and not previously tested by serological or molecular diagnostic methods. Overall, 213 (76.1 %) animals and 51 (43.6 %) ectoparasites were positive to L. infantum, with mean parasite loads of 795.2, 31.9 and 9.1 fg in dogs, cats and ectoparasites, respectively. Concerning the positivity between dogs and their ectoparasites, 32 (15.3 %) positive dogs were parasitized by positive ectoparasites. The overall concordance between the PCR protocols used was 59.2 %, with qPCR being more efficient than cPCR; 34.1 % of all positive samples were exclusively positive by qPCR. The high number of positive animals and ectoparasites also indicates that they could serve as sentinels or indicators of the circulation of L. infantum in risk areas.     

Efficiency of flagging and dragging for tick collection

It is acknowledged that data from field studies on tick ecology might be biased by collection methods, but actually comparative studies are still limited. Herein we assessed whether the efficiency of flagging and dragging varies according to tick developmental stage, species, season and habitat. Ticks were collected in three sites bordered by an oak forest. The abundance of ticks collected by each collection method varied according to tick species, developmental stage, season, and habitat. Flagging was in general more efficient in collecting adult ticks, especially in spring and winter. Females were more frequently collected by flagging in the meadow and grassland habitats and males in the man-made trail. Flagging collected significantly more adults of Dermacentor marginatus, Hyalomma marginatum, Haemaphysalis inermis and Ixodes ricinus. Flagging was more efficient in collecting D. marginatus and I. ricinus in spring, and H. inermis and I. ricinus females in both spring and winter. In summer and autumn tick abundances were generally similar, with the exception of D. marginatus female in autumn. Flagging was more efficient in collecting D. marginatus adults in the meadow habitat and in the man-made trail, and I. ricinus adults in the meadow and grassland habitats. Dragging was more efficient in grassland for R. turanicus. Our results suggest that variations in terms of collection method performance are associated to factors linked to tick behaviour, habitat characteristics, and climate. Field studies employing these collection methods should take this into account to avoid misleading conclusions about tick population dynamics and tick-borne pathogen transmission risk.     

Topical Enzyme-Replacement Therapy Restores Transglutaminase 1 Activity and Corrects Architecture of Transglutaminase-1-Deficient Skin Grafts

Transglutaminase-1 (TG1)-deficient autosomal-recessive congenital ichthyosis (ARCI) is a rare and severe genetic skin disease caused by mutations in TGM1. It is characterized by collodion babies at birth, dramatically increased transepidermal water loss (TEWL), and lifelong pronounced scaling. The disease has a tremendous burden, including the problem of stigmatization. Currently, no therapy targeting the molecular cause is available, and the therapeutic situation is deplorable. In this study, we developed the basis for a causative therapy aiming at the delivery of the enzyme to the inner site of the keratinocytes’ plasma membrane. We prepared sterically stabilized liposomes with encapsulated recombinant human TG1 (rhTG1) and equipped with a highly cationic lipopeptide vector to mediate cellular uptake. The liposomes overcame the problems of insufficient cutaneous delivery and membrane penetration and provided excellent availability and activity of rhTG1 in primary keratinocytes. To demonstrate the general feasibility of this therapeutic approach in a humanized context, we used a skin-humanized mouse model. Treatment with rhTG1 liposomes resulted in considerable improvement of the ichthyosis phenotype and in normalization of the regenerated ARCI skin: in situ monitoring showed a restoration of TG1 activity, and cholesterol clefts vanished ultrastructurally. Measurement of TEWL revealed a restoration of epidermal barrier function. We regard this aspect as a major advance over available nonspecific approaches making use of, for example, retinoid creams. We conclude that this topical approach is a promising strategy for restoring epidermal integrity and barrier function and provides a causal cure for individuals with TG1 deficiency.     

Aeromonas molluscorum Av27 is a potential tributyltin (TBT) bioremediator: phenotypic and genotypic characterization indicates its safe application

Aeromonas molluscorum Av27 is an estuarine bacterium highly resistant to tributyltin (TBT). Also, the strain is able to degrade TBT into the less toxic compounds dibutyltin and monobutyltin. Therefore, this bacterium has potential to be employed in bioremediation processes. In this context, defining its biological safety is crucial. With that purpose a number of intrinsic characteristics, usually present/associated with virulent strains, were investigated. Few virulence factors were detected in strain Av27. For instance, a DNase gene is present, but it is not apparently expressed in vitro. Motility, adherence factor and phospholipase activity were also detected. Additionally, cytotoxicity to Vero cells was negative. Resistance to penicillin (10 μg ml^?1), amoxicillin/clavulanic acid (30 μg ml^?1) and cephalothin (30 μg ml^?1) and also to the vibriostatic agent O/129 was observed. Five plasmids (4, 7, 10, 100 kb and one greater than 100 kb) were identified. No Class I and II integrons were detected. Study of the optimal growth conditions showed that Av27 easily adapts to different environmental conditions. Overall, the results suggest that A. molluscorum Av27 can be considered safe to use to bioremediate TBT in contaminated environments.     

Diffusion of individual birds in starling flocks

Flocking is a paradigmatic example of collective animal behaviour, where global order emerges out of self-organization. Each individual has a tendency to align its flight direction with those of neighbours, and such a simple form of interaction produces a state of collective motion of the group. When compared with other cases of collective ordering, a crucial feature of animal groups is that the interaction network is not fixed in time, as each individual moves and continuously changes its neighbours. The possibility to exchange neighbours strongly enhances the stability of global ordering and the way information is propagated through the group. Here, we assess the relevance of this mechanism in large flocks of starlings (Sturnus vulgaris). We find that birds move faster than Brownian walkers both with respect to the centre of mass of the flock, and with respect to each other. Moreover, this behaviour is strongly anisotropic with respect to the direction of motion of the flock. We also measure the amount of neighbours reshuffling and find that neighbours change in time exclusively as a consequence of the random fluctuations in the individual motion, so that no specific mechanism to keep one''s neighbours seems to be enforced. On the contrary, our findings suggest that a more complex dynamical process occurs at the border of the flock.     

Crops and fodder: evidence for storage and processing activities in a functional area at the Roman settlement of Monte Mozinho (northern Portugal)

Archaeobotanical material was recovered in two contiguous compartments of a compound in Monte Mozinho (Penafiel, northern Portugal). These areas comprise storage facilities from three different typologies—dolium, pits and above-ground quadrangular structures in the corner of the compartments. Few carpological materials were found inside the storage structures and all these are cereals which were most likely stored as clean grain. Recovered grains are probably remnants of the last stored crops prior to abandonment of the area. A radiocarbon date obtained on grains of rye positions this event at a time within the 3rd century and the beginning of the 4th century a.d. Outside the structures from compartment 2, abundant crop processing by-products, mostly weeds and chaff, were recovered. Since traditional agricultural communities tend not to waste such organic material, it is likely that it was kept in the area to be used as fodder. Data is ambiguous regarding the possible existence of fodder crops mixed with these by-products. Overall, there is a predominance of millets (Panicum miliaceum and Setaria italica) and rye (Secale cereale), but naked wheat (Triticum aestivum) is also a relevant crop. The presence of oat (Avena) is significant but it is difficult to interpret due to its exclusive presence alongside weeds and chaff. Grape pips (Vitis vinifera) were also found, but these are rare. The Late Roman carpological material from Monte Mozinho is of great relevance on a regional level. It documents and dates the presence of rye and testifies to a multifunctional system in which plant husbandry and animal breeding were intertwined.