The huge burden of malaria in developing countries urgently demands the development of novel approaches to fight this deadly disease. Although engineered symbiotic bacteria have been shown to render ...mosquitoes resistant to the parasite, the challenge remains to effectively introduce such bacteria into mosquito populations. We describe a Serratia bacterium strain (AS1) isolated from Anopheles ovaries that stably colonizes the mosquito midgut, female ovaries, and male accessory glands and spreads rapidly throughout mosquito populations. Serratia AS1 was genetically engineered for secretion of anti-Plasmodium effector proteins, and the recombinant strains inhibit development of Plasmodium falciparum in mosquitoes.
History and policy of biodiesel in Brazil Pousa, Gabriella P.A.G.; Santos, André L.F.; Suarez, Paulo A.Z.
Energy policy,
11/2007, Volume:
35, Issue:
11
Journal Article
Peer reviewed
Historically, during petroleum shortage, vegetable oils and their derivatives have been proposed as alternatives to petroleum diesel fuel. Since 1930, different approaches have been proposed by ...Brazilian's universities and research institutes, including the use of neat vegetable oils (pure or in blends) or their derivatives, such as hydrocarbons obtained by thermal-catalytic cracking and fatty acids’ methyl or ethyl esters (nowadays known as “biodiesel”) produced by alcoholysis. Recently, the external dependence on imported diesel fuel and the present petroleum crisis have increased the discussion in Brazil in the sense of starting to use alternatives to diesel fuel, biodiesel being the main alternative for a large petroleum diesel substitution program.
Many sequence variants have been linked to complex human traits and diseases
, but deciphering their biological functions remains challenging, as most of them reside in noncoding DNA. Here we have ...systematically assessed the binding of 270 human transcription factors to 95,886 noncoding variants in the human genome using an ultra-high-throughput multiplex protein-DNA binding assay, termed single-nucleotide polymorphism evaluation by systematic evolution of ligands by exponential enrichment (SNP-SELEX). The resulting 828 million measurements of transcription factor-DNA interactions enable estimation of the relative affinity of these transcription factors to each variant in vitro and evaluation of the current methods to predict the effects of noncoding variants on transcription factor binding. We show that the position weight matrices of most transcription factors lack sufficient predictive power, whereas the support vector machine combined with the gapped k-mer representation show much improved performance, when assessed on results from independent SNP-SELEX experiments involving a new set of 61,020 sequence variants. We report highly predictive models for 94 human transcription factors and demonstrate their utility in genome-wide association studies and understanding of the molecular pathways involved in diverse human traits and diseases.
Microbial sulfate reduction has governed Earth's biogeochemical sulfur cycle for at least 2.5 billion years. However, the enzymatic mechanisms behind this pathway are incompletely understood, ...particulary for the reduction of sulfite—a key intermediate in the pathway. This critical reaction is performed by DsrAB, a widespread enzyme also involved in other dissimilatory sulfur metabolisms. Using in vitro assays with an archaeal DsrAB, supported with genetic experiments in a bacterial system, we show that the product of sulfite reduction by DsrAB is a protein-based trisulfide, in which a sulfite-derived sulfur is bridging two conserved cysteines of DsrC. Physiological studies also reveal that sulfate reduction rates are determined by cellular levels of DsrC. Dissimilatory sulfate reduction couples the four-electron reduction of the DsrC trisulfide to energy conservation.
•Parameters of AGS formation were reviewed, and reference values were proposed.•Parameters of AGS maintenance were reviewed, and reference values were proposed.•The main metabolic pathways for ...removal of some compounds by AGS were discussed.•Microbial groups present in AGS and their respective functions were discussed.•The favoring strategies for AOB, NOB, PAO and GAO in AGS were proposed.
Aerobic granular sludge (AGS) has been the focus of many investigations, and the main parameters responsible for AGS formation are hydrodynamic shear force, short periods and feast-famine cycles. However, some other parameters are associated with AGS maintenance after long periods of operation. This review evaluates the parameters responsible for AGS formation and maintenance and some reference values are proposed. In addition, some discussions are addressed about the main metabolic pathways that AGS uses for the removal of some compounds, such as nutrients, organic matter, dyes, recalcitrant compounds, among others. Finally, the main microbial groups present in the AGS and their respective functions are discussed. It is also highlighted that many parameters that are taken as reference currently for AGS cultivation and maintenance can be optimized for energy savings, implementation costs, among others, as well as a greater recovery of resources during wastewater treatment, within the scope of the biorefinery concept.
We aimed to determine the conservation status of medium- and large-sized mammals and evaluate the impact of 500 years of forest fragmentation on this group of animals in the Pernambuco Endemism ...Center, in the biogeographical zone of the Atlantic forest north of the São Francisco River in northeastern Brazil. Line transect surveys were performed in 21 forest fragments, resulting in a checklist of the mammals of the entire Pernambuco Endemism Center area. We ran a generalized linear model (Factorial ANCOVA) to analyze to what extent the vegetation type, fragment area, isolation, sampling effort (as total kilometers walked), or higher-order interactions predicted (a) richness and (b) sighting rates. To determine if the distribution of the species within the forest fragments exhibited a nested pattern, we used the NODF metric. Subsequently, we performed a Binomial Logistic Regression to predict the probability of encountering each species according to fragment size. Out of 38 medium- and large-sized mammal species formerly occurring in the study area, only 53.8% (n = 21) were sighted. No fragment hosted the entire remaining mammal community, and only four species (19%) occurred in very small fragments (73.3% of the remaining forest fragments, with a mean size of 2.8 ha). The mammalian community was highly simplified, with all large mammals being regionally extinct. Neither the species richness nor sighting rate was controlled by the vegetation type, the area of the forest fragments, isolation or any higher-order interaction. Although a highly significant nested subset pattern was detected, it was not related to the ranking of the area of forest fragments or isolation. The probability of the occurrence of a mammal species in a given forest patch varied unpredictably, and the probability of detecting larger species was even observed to decrease with increasing patch size. In an ongoing process of mass extinction, half of the studied mammals have gone extinct. The remaining medium-sized mammal community is highly simplified and homogenized. The persistence of these species in a forest patch is determined by their ability to adapt to a novel simplified diet, the efficient use of the surrounding matrix without being engulfed by the sink effect, and escaping hunting. Our results suggest that the 21st century medium-sized mammalian fauna of this region will comprise only four species unless strict conservation measures are implemented immediately and every forest fragment is effectively protected.
As a reaction against contemporary democracy's inherent short-sightedness in solving problems that are likely to affect distant future generations, there has been a recent increase in proposals for ...different kinds of democratic representation of future persons. This article shows that even though there can be no such thing as political representation of future persons, the relevant affected interests of the as-yet unborn can still be taken into consideration in political decision making. This aim is achieved by focusing on the political representation of children as special cases of semi-future members of the class of the represented.
In the present study, we have described the synthesis and characterisation of the theophylline hydrate (Theo hydrate), cocrystal (Theo-Phen·2H
2
O) and hydrated sodium co-crystal of theophylline ...(Na-(Theo)
2
ClO·2H
2
O), where Theo = theophylline and Phen = 1,10-phenathroline. SC-XRD characterisation revealed strong interactions such as N H O, C&z.dbd;O H and C-H π within the crystal structures. Studies revealed that Na-(Theo)
2
ClO·2H
2
O presented higher thermal stability (in the solid form) and improved solubility (when in contact with a polar solvent). The detailed analyses of Hirshfeld surface and fingerprint plots provided insight into the nature of non-covalent interactions in the compounds. In the case of Na-(Theo)
2
ClO·2H
2
O, solubility measurements indicated that Theo's solubility in water increases by a magnitude of four with respect to pure Theo. Biological studies showed that the high solubility of Theo as well as ClO
4
−
is responsible for the distinct capabilities to inhibit the growth of different microorganisms, including Gram-positive (
Staphylococcus epidermidis
) and Gram-negative (
Acinetobacter baumannii
,
Escherichia coli
and
Klebsiella pneumoniae
) bacteria and fungi (
Candida albicans
and
Candida tropicalis
). Our results pointed out that cocrystals containing theophylline-phenanthroline can be explored to get promising molecules to be used to combat infections caused by clinically relevant (multi)drug-resistant bacteria and fungi.
In the present study, we have described the synthesis and characterisation of the theophylline hydrate (Theo hydrate), cocrystal (Theo-Phen·2H
2
O) and hydrated sodium co-crystal of theophylline (Na-(Theo)
2
ClO·2H
2
O), where Theo = theophylline and Phen = 1,10-phenathroline.
Cell disruption can increase the extraction efficiency of total lipids from microalgae for further conversion to biodiesel. Four different pretreatment methods were tested on mixed cultures of ...microalgae harvested in a stabilization pond system treating sewage: ultrasonication (US), microwaving (MW), autoclave (AC) and electroflotation by alternating current (EFAC). The best results in terms of total lipid yield were: MW (33.7 ± 5.3%), followed by EFAC (24.8 ± 7.1%), AC (15.4 ± 2.3%), and US (13.3 ± 3.0%). However, when both efficiency and costs are considered, EFAC gave the best result and can be an excellent option for simultaneous microalgae harvesting and cell disruption.
•Microalgae cell disruption methods for mixed culture.•Effect of microalgal cell disruption on lipid yield.•Electroflotation by alternating current as a pretreatment method.•Energetic feasibility of the most efficient methods.
A common choice for Linear Fresnel Reflector primary mirrors is the so-called uniform configuration, in which a constant value of mirror width – and their relative distances – is used. Often, it ...results in large relative mirror distances, leading to significant losses of etendue and concentration due to the light lost between the mirrors. In this paper a method to optimize the position of primary mirrors is presented with the goal of producing a more continuous primary optic, eventually closer to the theoretical limits of solar concentration. This calculation was done for two Linear Fresnel Reflector concentrators with uniform configurations, exploring how this method can improve the performance of such systems. This paper analyses the impact of such modifications on the overall optical performance of the collector, through the calculation of Concentration-Acceptance Product, Incidence Angle Modifier curves and an estimation of the total amount of collected energy for a specific location, Faro (Portugal). For the analyzed cases, the simulation results show that the proposed method produces denser primary fields, with an increase up to 21% in mirror area and collecting up to 14% more energy.
•A novel design method for linear Fresnel primaries was presented.•The designed concentrators have higher Concentration Acceptance Product.•Denser primary fields have more transversal losses.•Increase in annual energy collection up to 14% was achieved.•The designed fields collect less energy per unit of reflective area.
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