Rate of Contaminant Bioavailability in Artificial Soil-Water Column Experiments

Bioavailability of organic contaminants is a key parameter in estimating the fate and transport of contaminants in the environment. Its quantification is necessary for assessing the bioremediation potential of a contaminated site or for evaluating the hazard associated with the presence of the contaminant. However, there is a lack of methods that quantify biovailability under flow-through conditions. Therefore, a method was developed based on mass-balance analysis of contaminant breakthrough curves to quantify a bioavailability rate. The method was performed on an eight-column study where pentachlorophenol (PCP) was injected through saturated columns packed with a blend of sterile or inoculated sand and PCP-sorbing resin. Columns varied in sorption capacity, pore-water velocity and biodegradation activity. Breakthrough curves were modeled using a classic approach that includes advection-dispersion, equilibrium and first-order sorption, as well as biodegradation. Results showed that the bioavailability rates (non-dimensional numbers ranging from 0.02 for a sorptive column to 0.32 for a non-sorptive one) were directly related to the limiting kinetic mechanism. It was also demonstrated that the contaminant aqueous phase concentration does not adequately represent its bioavailability under flow-through conditions.     

Homogeneous recombinant Mycobacterium tuberculosis shikimate dehydrogenase production: An essential step towards target-based drug design

Mycobacterium tuberculosis shikimate dehydrogenase (MtbSD) catalyzes the forth reaction in the shikimate pathway. Here we describe production of K69A, K69H, K69I, K69Q, D105A, and D105N mutant proteins. Screening of several conditions was performed to optimize MtbSD production yield, and an improved purification protocol to obtain homogeneous MtbSD is presented. The rational design of new antitubercular drugs hinges on the availability of M. tuberculosis proteins. Our results show that optimization of expression, disruption, and purification protocols resulted in a higher yield of functional MtbSD enzyme.     

Extra and Intracellular Synthesis of Nickel Oxide Nanoparticles Mediated by Dead Fungal Biomass

The use of dead biomass of the fungus Hypocrea lixii as a biological system is a new, effective and environmentally friendly bioprocess for the production and uptake of nickel oxide nanoparticles (NPs), which has become a promising field in nanobiotechnology. Dead biomass of the fungus was successfully used to convert nickel ions into nickel oxide NPs in aqueous solution. These NPs accumulated intracellularly and extracellularly on the cell wall surface through biosorption. The average size, morphology and location of the NPs were characterized by transmission electron microscopy, high-resolution transmission electron microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The NPs were mainly spherical and extra and intracellular NPs had an average size of 3.8 nm and 1.25 nm, respectively. X-ray photoelectron spectroscopy analysis confirmed the formation of nickel oxide NPs. Infrared spectroscopy detected the presence of functional amide groups, which are probable involved in particle binding to the biomass. The production of the NPs by dead biomass was analyzed by determining physicochemical parameters and equilibrium concentrations. The present study opens new perspectives for the biosynthesis of nanomaterials, which could become a potential biosorbent for the removal of toxic metals from polluted sites.     

Effects of Extrusion on the Emulsifying Properties of Rumen and Soy Protein

Defatted rumen protein and soy protein concentrate were extruded in a 15.5:1 L/D single-screw extruder at the optimum conditions for their expansion (150°C and 35% moisture, and 130°C and 35% moisture, respectively). Emulsions were produced with these proteins and studied by rheology and time domain low-resolution ¹H nuclear magnetic resonance (TD-NMR). Extrusion increased storage modulus of rumen protein emulsions. The opposite was observed for soy protein. Mechanical relaxation showed the existence of three relaxing components in the emulsions whose relative contributions were changed by extrusion. Likewise, spin–spin relaxation time constants (T ₂) measured by TD-NMR also showed three major distinct populations of protons in respect to their mobility that were also altered by extrusion. Extrusion increased surface hydrophobicity of both rumen and soy protein. Solubility of rumen protein increased with extrusion whereas soy protein had its solubility decreased after processing. Extrusion promoted molecular reorganization of protein, increasing its superficial hydrophobicity, affecting its interfacial properties and improving its emulsifying behavior. The results show that extrusion can promote the use of rumen, a by-product waste from the meat industry, in human nutrition by replacing soy protein in food emulsions.     

Influence of beta-D-xyloside on growth and histological aspect of long bones in chicken embryos

It is known that beta-D-xylosides interfere with the proteoglycan synthesis in several tissues. A possible influence of this disturbed synthesis on the matrix formation of bone and cartilage has not been described light microscopically. In the present study we used 10-day-old chicken embryos which were exposed in ovo to a final concentration of 0.5 mM beta-D-xyloside. After 3, 6, 9, 20, 25, 31, 35 and 40 days, lengths of several skeletal elements were determined and the middle metatarsal bones were processed for light microscopical demonstration of acidic groups. The results demonstrate that beta-D-xyloside inhibits growth of long bones and induces synthesis of a cartilage matrix with a very low concentration of chondroitin sulphate. It has no noticeable influence on the amount of acidic groups in the organic bone matrix. Despite the absence of chondroitin sulphate, the cartilage matrix becomes mineralized normally.     

Ventilation Onset Prior to Umbilical Cord Clamping (Physiological-Based Cord Clamping) Improves Systemic and Cerebral Oxygenation in Preterm Lambs

BackgroundAs measurement of arterial oxygen saturation (SpO₂) is common in the delivery room, target SpO₂ ranges allow clinicians to titrate oxygen therapy for preterm infants in order to achieve saturation levels similar to those seen in normal term infants in the first minutes of life. However, the influence of the onset of ventilation and the timing of cord clamping on systemic and cerebral oxygenation is not known.AimWe investigated whether the initiation of ventilation, prior to, or after umbilical cord clamping, altered systemic and cerebral oxygenation in preterm lambs.MethodsSystemic and cerebral blood-flows, pressures and peripheral SpO₂ and regional cerebral tissue oxygenation (SctO₂) were measured continuously in apnoeic preterm lambs (126±1 day gestation). Positive pressure ventilation was initiated either 1) prior to umbilical cord clamping, or 2) after umbilical cord clamping. Lambs were monitored intensively prior to intervention, and for 10 minutes following umbilical cord clamping.ResultsClamping the umbilical cord prior to ventilation resulted in a rapid decrease in SpO₂ and SctO₂, and an increase in arterial pressure, cerebral blood flow and cerebral oxygen extraction. Ventilation restored oxygenation and haemodynamics by 5–6 minutes. No such disturbances in peripheral or cerebral oxygenation and haemodynamics were observed when ventilation was initiated prior to cord clamping.ConclusionThe establishment of ventilation prior to umbilical cord clamping facilitated a smooth transition to systemic and cerebral oxygenation following birth. SpO₂ nomograms may need to be re-evaluated to reflect physiological management of preterm infants in the delivery room.     

The Paleoparasitology in Brazil and Findings in Human Remains from South America: A Review

The review article presents some of the history of how paleoparasitology started in Brazil, making highlight the great responsible Dr. Luiz Fernando Ferreira and Dr. Adauto Araújo, the trajectory of paleoparasitology in Brazil since 1978 and its performance in science to the present day. In sequence, it is made a presentation of parasitological findings on human remains found in archaeological sites in South America, highlighting Brazil, Argentina, Chile, and Peru, where major discoveries have occurred. Many of the parasites found in archaeological material and mentioned in this review went out of Africa with the peopling of Europe and from there they dispersed around the world, where climatic conditions allow the transmission. However, humans have acquired other parasites of animals, since humans invaded new habitats or creating new habits adopting new technologies, thus expanding its range of influence on the environment. Thus, this review article is finalized with information that explain the importance of these findings in the interaction between parasites, human host, and ambient.