BrtB is an O-alkylating enzyme that generates fatty acid-bartoloside esters

Esterification reactions are central to many aspects of industrial and biological chemistry. The formation of carboxyesters typically occurs through nucleophilic attack of an alcohol onto the carboxylate carbon. Under certain conditions employed in organic synthesis, the carboxylate nucleophile can be alkylated to generate esters from alkyl halides, but this reaction has only been observed transiently in enzymatic chemistry. Here, we report a carboxylate alkylating enzyme – BrtB – that catalyzes O-C bond formation between free fatty acids of varying chain length and the secondary alkyl halide moieties found in the bartolosides. Guided by this reactivity, we uncovered a variety of natural fatty acid-bartoloside esters, previously unrecognized products of the bartoloside biosynthetic gene cluster. © 2020, The Author(s).We acknowledge funding by the European Research Council, through a Starting Grant (Grant Agreement 759840) to P.N.L., and by Fundação para a Ciência e Tecnologia (FCT) through project PTDC/BIA-BQM/29710/2017 and grant IF/01358/2014 to P.N.L. The work was also partially supported by Strategic Funding UIDB/04423/2020 and UIDP/04423/2020 by FCT and the European Regional Development Fund, as part of the program PT2020. We thank Emily Balskus (Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA) for helpful discussions and Ralph Urbatzka (CIIMAR, University of Porto, Porto, Portugal) for help with cytotoxicity assays

Expression of a hantavirus N protein and its efficacy as antigen in immune assays

Hantavirus cardiopulmonary syndrome (HCPS) has been recognized as an important public heath problem. Five hantaviruses associated with HCPS are currently known in Brazil: Juquitiba, Araraquara, Laguna Negra-like, Castelo dos Sonhos, and Anajatuba viruses. The laboratory diagnosis of HCPS is routinely carried out by the detection of anti-hantavirus IgM and/or IgG antibodies. The present study describes the expression of the N protein of a hantavirus detected in the blood sample of an HCPS patient. The entire S segment of the virus was amplified and found to be 1858 nucleotides long, with an open reading frame of 1287 nucleotides that encodes a protein of 429 amino acids. The nucleotide sequence described here showed a high identity with the N protein gene of Araraquara virus. The entire N protein was expressed using the vector pET200D and the Escherichia coli BL21 strain. The expression of the recombinant protein was confirmed by the detection of a 52-kDa protein by Western blot using a pool of human sera obtained from HCPS patients, and by specific IgG detection in five serum samples of HCPS patients tested by ELISA. These results suggest that the recombinant N protein could be used as an antigen for the serological screening of hantavirus infection.FAPES

High efficiency bias stabilisation for resonant tunneling diode oscillators

We report on high-efficiency, high-power, and low-phase-noise resonant tunneling diode (RTD) oscillators operating at around 30 GHz. By employing a bias stabilization network, which does not draw any direct current (dc), the oscillators exhibit over a tenfold improvement in the dc-to-RF conversion efficiency (of up to 14.7%) compared to conventional designs (~0.9%). The oscillators provide a high maximum output power of around 2 dBm, and low phase noise of -100 and -113 dBc/Hz at 100 kHz and 1 MHz offset frequencies, respectively. The proposed approach will be invaluable for realizing very high efficiency, low phase noise, and high-power millimeter-wave (mm-wave) and terahertz (THz) RTD-based sources

Accurate small-signal equivalent circuit modelling of resonant tunneling diodes to 110 GHz

This article presents a novel, on-wafer deembedding technique for the accurate small-signal equivalent circuit modeling of resonant tunneling diodes (RTDs). The approach is applicable to stabilized RTDs, and so enables the modeling of the negative differential resistance (NDR) region of the device's current-voltage (I-V) characteristics. Furthermore, a novel quasi-analytical procedure to determine all the equivalent circuit elements from the deembedded S-parameter data is developed. Extraction results of a 10 μm × 10 μm stabilized, low-current density RTD at different bias points show excellent fits between modeled and measured S-parameters up to 110 GHz

Origin and main ramifications of coeliac artery in Cerdocyon thous

Background: Cerdocyon thous is the canid with the greatest geographical coverage in South America. The aim of this study was to describe the origin, skeletopy, length and main branches of the coeliac artery in C. thous. Materials and methods: The dissections were performed on 14 cadavers of adult specimens, 6 males and 8 females, with a rostrosacral length average of 67.00 ± 4.7 cm and 62.09 ± 5.7 cm, respectively. The specimens were collected dead on highways on the banks of the Atlantic Forest (Rio de Janeiro) and the Pampa biome (Rio Grande do Sul) in Brazil. The cadavers were fixed and preserved in a formaldehyde solution until dissection. The coeliac artery was dissected, the length was measured “in situ” and its main branches were recorded. The coeliac artery emerged as a single artery in all dissected animals. Results: The average length of the coeliac artery was 1.43 ± 0.17 cm in males and 1.39 mm ± 0.24 cm in females, with no significant difference in this measurement between sexes. The predominant skeletopy was at the level of the second lumbar vertebra (57.1%), positioned on average 1.43 cm cranially to the cranial mesenteric artery. In most individuals (92.9%), the classic trifurcation was formed: the coeliac artery branched into the hepatic, left gastric, and lienal arteries. Only 1 male animal presented a bifurcation formed between the hepatic artery and a gastrolienal trunk. Conclusions: These anatomical characteristics are similar to those of other species of the Canidae family, possibly due to their phylogenetic proximity

Evaluating pathway enumeration algorithms in metabolic engineering case studies

The design of cell factories for the production of compounds involves the search for suitable heterologous pathways. Different strategies have been proposed to infer such pathways, but most are optimization approaches with specific objective functions, not suited to enumerate multiple pathways. In this work, we analyze two pathway enumeration algorithms based on graph representations: the Solution Structure Generation and the Find Path algorithms. Both are capable of enumerating exhaustively multiple pathways using network topology. We study their capabilities and limitations when designing novel heterologous pathways, by applying these methods on two case studies of synthetic metabolic engineering related to the production of butanol and vanillin

Protecção integrada em tomate de indústria: modelo de previsão do míldio

In Portugal, the processing tomato is of great economical importance. The maintenance of the quality of the final product is of growing preoccupation due to the ever increasing consumer demand. IPM has been considered as the best alternative due to the guarantee of some of these demands, in particular the non existence of pesticide residues. The objectives of the work carried out in the Ribatejo were to establish risk assessment methodologies and decision rules for the main enemies of the tomato crop and also to contribute for IPM development in this area. Of these main enemies late blight and the fruitworm are of great importance and determine the treatment schemes. The rationalization of the treatments is based on: the reduction of the fungicide interventions by better timing and the substitution of the insecticides by non chemical alternatives. For the prior we intend to adapt an existing model the “Tom-cast” which is largely used in Mexico. The present study presents the model and describes the first steps that have been taken in validating the model in the conditions of the Ribatejo. The results are an indication of the strong potential of the model. The next two years prospects and orientation are also presented

Brain-inspired nanophotonic spike computing:challenges and prospects

Nanophotonic spiking neural networks (SNNs) based on neuron-like excitable subwavelength (submicrometre) devices are of key importance for realizing brain-inspired, power-efficient artificial intelligence (AI) systems with high degree of parallelism and energy efficiency. Despite significant advances in neuromorphic photonics, compact and efficient nanophotonic elements for spiking signal emission and detection, as required for spike-based computation, remain largely unexplored. In this invited perspective, we outline the main challenges, early achievements, and opportunities toward a key-enabling photonic neuro-architecture using III-V/Si integrated spiking nodes based on nanoscale resonant tunnelling diodes (nanoRTDs) with folded negative differential resistance. We utilize nanoRTDs as nonlinear artificial neurons capable of spiking at high-speeds. We discuss the prospects for monolithic integration of nanoRTDs with nanoscale light-emitting diodes and nanolaser diodes, and nanophotodetectors to realize neuron emitter and receiver spiking nodes, respectively. Such layout would have a small footprint, fast operation, and low power consumption, all key requirements for efficient nano-optoelectronic spiking operation. We discuss how silicon photonics interconnects, integrated photorefractive interconnects, and 3D waveguide polymeric interconnections can be used for interconnecting the emitter-receiver spiking photonic neural nodes. Finally, using numerical simulations of artificial neuron models, we present spike-based spatio-temporal learning methods for applications in relevant AI-based functional tasks, such as image pattern recognition, edge detection, and SNNs for inference and learning. Future developments in neuromorphic spiking photonic nanocircuits, as outlined here, will significantly boost the processing and transmission capabilities of next-generation nanophotonic spike-based neuromorphic architectures for energy-efficient AI applications. This perspective paper is a result of the European Union funded research project ChipAI in the frame of the Horizon 2020 Future and Emerging Technologies Open programme.</p

The INTERFRUTA II project and the study of phytossanitary problems that affect Azorean fruit orchards and vineyards

The INTERFRUTA project is financed by the European Commission Interreg III-B Programme and was developed for the islands of “Madeira”, “Tenerife” and “Terceira”, for the improvement of fruit and vineyard production in these three Atlantic regions. The project goal is a better knowledge of the phytossanitary problems that affect apples, bananas, chestnut and vineyards, applying methods that will contribute to solutions based on the survey of key pests, diseases and beneficial organisms. In the three fruit crops and vineyards analyzed, the methodology used was mainly direct observation of predefined parts of each plant (such as leaves and flowers) on which pests might be expected to occur. The key pest C. capitata was monitored as adults using sexual lures in a net of traps around the island of “Terceira” up to 200 meters altitude. The beneficial insect survey was conducted using the beating technique. For diseases, a direct sampling was carried out by the observation of 10 % of the plants in each orchard or vineyard plot looking for visible symptoms. In apples and vineyards, flowers and branches were collected and tested for microorganisms using serologic and molecular techniques (Elisa and PCR). In banana plantations, the most damaging pests were banana weevil, thrips and a fungi complex that causes symptoms similar to Fusarium wilt. In chestnut, the pest that causes the most severe damage, affecting around 40 % of the nuts produced, is the Chestnut tortrix, but there were some difficulties in identifying which of the three known species was present in the Azores islands. In vineyards, diseases that are most frequent and important include grapevine downy mildew, powdery mildew and Botrytis. Invertebrate pests included grape leafhoppers, thrips and eriophyid mites. The European vine moth was also surveyed but none were found and is still not present. In apple orchards the most important problems were thrips, mites, oriental fruit moth and codling moth. Anarsia lineatella Zeller, the peach twig borer, was not detected and new Eriophyid species have been recorded for the first time in the Azores as a result of the surveys. With the information collected it was possible to create a phytossanitary diagnostic database for the Macaronesian islands (PROFITOMAC) on the project internet pages (www.interfruta.uac.pt), to help users to identify problems that affect the studied cultures