Biocompatibility of Brazilian native yeast-derived sophorolipids and Trichoderma harzianum as plant-growth promoting bioformulations.

The replacement of agrochemicals by biomolecules is imperative to mitigate soil contamination and inactivation of its core microbiota. Within this context, this study aimed at the interaction between a biological control agent such as Trichoderma harzianum CCT 2160 (BF-Th) and the biosurfactants (BSs) derived from the native Brazilian yeast Starmerella bombicola UFMG-CM-Y6419. Thereafter, their potential in germination of Oryza sativa L. seeds was tested. Both bioproducts were produced on site and characterized according to their chemical composition by HPLC-MS and GC-MS for BSs and SDS-PAGE gel for BF-Th. The BSs were confirmed to be sophorolipids (SLs) which is a well-studied compound with antimicrobial activity. The biocompatibility was examined by cultivating the fungus with SLs supplementation ranging from 0.1 to 2 g/L in solid and submerged fermentation. In solid state fermentation the supplementation of SLs enhanced spore production, conferring the synergy of both bioproducts. For the germination assays, bioformulations composed of SLs, BF-Th and combined (SLT) were applied in the germination of O. sativa L seeds achieving an improvement of up to 30% in morphological aspects such as root and shoot size as well as the presence of lateral roots. It was hypothesized that SLs were able to regulate phytohormones expression such as auxins and gibberellins during early stage of growth, pointing to their novel plant-growth stimulating properties. Thus, this study has pointed to the potential of hybrid bioformulations composed of biosurfactants and active endophytic fungal spores in order to augment the plant fitness and possibly the control of diseases.

Automated detection of auditory response: non-detection stopping criterion and repeatability studies for multichannel EEG.

An Auditory Steady-State Response (ASSR) is a valuable tool for determining auditory thresholds in individuals who are either unable or unwilling to cooperate with conventional behavioral testing methods. This study proposes a sequential test technique for automatic detection of ASSRs, incorporating a non-detection stopping criterion. The electrophysiological thresholds of a normal hearing volunteer were established using data collected from multichannel EEG signals. The detection probabilities and critical values were obtained via Monte Carlo simulations. Remarkably, application of the non-detection stopping criterion resulted in a 60% reduction in exam time in the absence of a response. These findings clearly demonstrate the significant potential of the sequential test in enhancing the performance of automatic audiometry.

Production and applications of pullulan from lignocellulosic biomass: Challenges and perspectives.

Pullulan is an exopolysaccharide produced by Aureobasidium pullulans, with interesting characteristics which lead to its application in industries such as pharmaceuticals, cosmetics, food, and others. To reduce production costs for industrial applications, cheaper raw materials such as lignocellulosic biomass can be utilized as a carbon and nutrient source for the microbial process. In this study, a comprehensive and critical review was conducted, encompassing the pullulan production process and the key influential variables. The main properties of the biopolymer were presented, and different applications were discussed. Subsequently, the utilization of lignocellulosics for pullulan production within the framework of a biorefinery concept was explored, considering the main published works that deal with materials such as sugarcane bagasse, rice husk, corn straw, and corn cob. Next, the main challenges and future prospects in this research area were highlighted, indicating the key strategies to favor the industrial production of pullulan from lignocellulosic biomasses.

Dealing with correlations in the multichannel EEG using bipolar derivations and Monte Carlo simulations: application to the detection of auditory steady-state responses.

The multichannel objective response detection (MORD) techniques are statistical methods, which use information from more than one electroencephalography (EEG) channel, to infer the presence of evoked potential. However, the correlation level between the channels can lead to a decrease in MORD performance, such as an increase in the false positive (FP) rate and/or a decrease in the detection rate (DR). The present study aims to propose a method to deal with the correlations in the multichannel EEG. The method consists of making an adjustment in the Monte Carlo simulation, considering the information between channels. The MORD techniques with and without the new method were applied to an auditory steady-state response (ASSR) database, composed of the EEG multichannel of eleven volunteers during multifrequency stimulation. The proposed method kept the FP rate at values equal to or less than the significance level of the test and led to an increase of 8.51% in the DR in relation to non-application of the method. Results of this study indicate that the proposed method is an alternative to deal with the effect of the correlation between channels in situations where MORD techniques are applied.

Surfactants, Biosurfactants, and Non-Catalytic Proteins as Key Molecules to Enhance Enzymatic Hydrolysis of Lignocellulosic Biomass.

Lignocellulosic biomass (LCB) has remained a latent alternative resource to be the main substitute for oil and its derivatives in a biorefinery concept. However, its complex structure and the underdeveloped technologies for its large-scale processing keep it in a state of constant study trying to establish a consolidated process. In intensive processes, enzymes have been shown to be important molecules for the fractionation and conversion of LCB into biofuels and high-value-added molecules. However, operational challenges must be overcome before enzyme technology can be the main resource for obtaining second-generation sugars. The use of additives is shown to be a suitable strategy to improve the saccharification process. This review describes the mechanisms, roles, and effects of using additives, such as surfactants, biosurfactants, and non-catalytic proteins, separately and integrated into the enzymatic hydrolysis process of lignocellulosic biomass. In doing so, it provides a technical background in which operational biomass processing hurdles such as solids and enzymatic loadings, pretreatment burdens, and the unproductive adsorption phenomenon can be addressed.

Automatic audiometry using auditory steady-state response and sequential test strategy applied to volunteers with normal hearing.

PURPOSE: In the present study, a new procedure to perform automatic audiometry using multifrequency Auditory Steady-State Response (ASSR) is proposed. METHODS: The automatic audiometry procedure consists of detecting the presence of multifrequency ASSR in real-time using the sequential test strategy and by adjusting the stimulus intensity independently. The ASSR audiometric thresholds of 18 adult volunteers with normal hearing were determined by automatically (four simultaneous frequencies per ear) at modulation frequencies in the 80 Hz range. The exam time and the difference between ASSR thresholds and pure-tone behavioural hearing thresholds were estimated as performance measures. RESULTS: The results showed that automatic audiometry can reduce the number of intensity levels used to obtain the ASSR threshold by up to 58% when compared to audiometry without using the techniques applied in automatic audiometry. In addition, the average of the difference between ASSR thresholds and Pure-Tone Behavioural Hearing thresholds was around 19 dB, which is similar to the results reported in similar studies. CONCLUSIONS: The audiometric procedure proposed in this study is fully automatic, i.e., does not require any human supervision throughout the exam, and is able to significantly reduce the conventional exam time.

Surfactants in biorefineries: Role, challenges & perspectives.

The use of lignocellulosic biomass (LCB) as feedstock has received increasing attention as an alternative to fossil-based refineries. Initial steps such as pretreatment and enzymatic hydrolysis are essential to breakdown the complex structure of LCB to make the sugar molecules available to obtain bioproducts by fermentation. However, these steps increase the cost of the bioproduct and often reduces its competitiveness against synthetic products. Currently, the use of surfactants has shown considerable potential to enhance lignocellulosic biomass processing. This review addresses the main mechanisms and role of surfactants as key molecules in various steps of biorefinery processes, viz., increasing the removal of lignin and hemicellulose during the pretreatments, increasing enzymatic stability and enhancing the accessibility of enzymes to the polymeric fractions, and improving the downstream process during fermentation. Further, technical advances, challenges in application of surfactants, and future perspectives to augment the production of several high value-added bioproducts have been discussed.

Interação entre polaridades afetivas e espaciais: preferências no futebol e compatibilidade estímulo-resposta / Interaction between affective and spatial polarities: soccer preferences and stimulus-response compatibility / Interacción entre polaridades afectivas y espaciales: preferencias futbolísticas y compatibilidad estímulo-respuesta

A valência afetiva de estímulos visuais provoca reações de aproximação e afastamento para estímulos positivos e negativos, respectivamente. Na tarefa de Simon, o tempo de reação é menor quando o estímulo e a resposta estão do mesmo lado (condição correspondente) do que quando estão em lados opostos (condição não-correspondente). A diferença entre os tempos de reação é o efeito Simon. Neste trabalho, foi investigado como as valências afetivas dos times Preferido e Rival influenciam o efeito Simon. Os resultados mostraram um maior efeito Simon para o time Preferido, indicando que a valência positiva do Preferido facilita a resposta correspondente.

The affective valence of visual stimuli elicits approach and avoidance reactions to positive and negative stimuli, respectively. In Simon task, the reaction time is shorter when the stimulus and the response are on the same side (corresponding condition) than when they are on opposite sides (non-corresponding condition). The difference between the reaction times is the Simon effect. This work investigated how the affective valences of the Favorite and Rival teams influence the Simon effect. The results showed a bigger Simon effect for the Favorite team, suggesting that the Favorite positive valence facilitates the corresponding response.

La valencia afectiva de los estímulos visuales provoca reacciones de aproximación y evitación a estímulos positivos y negativos, respectivamente. En la tarea de Simon, el tiempo de reacción es menor cuando el estímulo y la respuesta están del mismo lado (condición correspondiente) que cuando están en lados opuestos (condición no-correspondiente). La diferencia entre los tiempos de reacción es el efecto Simon. En este trabajo se investigó cómo las valencias afectivas de los equipos Favorito y Rival influyen en el efecto Simon. Los resultados mostraron que el efecto Simon para el equipo Favorito es mayor, lo que sugiere que la valencia positiva del equipo Favorito facilita la respuesta correspondiente.

Multichannel search strategy for improving the detection of auditory steady-state response.

Auditory steady-state response (ASSR) is useful for hearing threshold estimation. The ASSR is usually detected with objective response detectors (ORD). The performance of these detectors depends on the signal-to-noise ratio (SNR) as well as the signal length. Since it is undesirable to increase the signal length, then, this work provides a multivariate technique for improving the SNR and consequently the detection power. We propose the insertion of a short calibration step before the detection protocol, in order to perform a search among the available electroencephalogram (EEG) derivations and select the derivation with the highest SNR. The ORD used in this work was the magnitude-squared coherence (MSC). The standard detection protocol is to use the same EEG derivation in all exams. Using 22-scalp positions, the new technique achieved a detection rate higher than that obtained in 99.13% of the standard detection protocol. When restrictions were applied to the search, a superior performance was achieved. Thus, the technique proposed was able to track the best EEG derivations before exams and seems to be able to deal with the variability between individuals and between sessions.

Utilization of sugarcane straw for production of ß-glucan biopolymer by Lasiodiplodia theobromae CCT 3966 in batch fermentation process.

ß-Glucans as emerging biopolymer are widely produced by microorganisms in fermentation processes using commercial sugars which make process non-economic. Lignocellulosic substances are inexpensive carbon sources, which could be exploited for sustainable production of ß-glucans. In this study, a lignocellulosic material, namely sugarcane straw (SCS) was utilized for the production of extracellular ß-glucan by Lasiodiplodia theobromae CCT3966. SCS was subjected to acid and subsequent alkaline pretreatment, followed by enzymatic saccharification using cellulase enzyme. Quantity of 48.65 g/L glucose was released after enzymatic hydrolysis. ß-Glucan production was performed by cultivation of fungal strain in SCS hydrolysate at 28 °C and initial culture pH 7. Highest ß-glucan yield and productivity of 0.047 gg-1 and 0.014 gL-1h-1, respectively was obtained at 72 h fermentation time. Kinetic study of ß-glucan production revealed experimental biosynthesis of ß-glucan from SCS hydrolysate followed the trend generated by Logistic and Luedeking-Piret models. Chemical structure of biopolymer produced showed ß-glucan constitution.

Biological function and molecular properties of Pyrenaican SF-1 as biological macromolecule extracted from Daldinia pyrenaica.

Molecular properties and biological functions of Pyrenaican SF-1 as a novel biological macromolecule extracted from a fungal isolate were studied. The isolate was identified as Daldinia pyrenaica on the basis of 5.8S rDNA sequencing. Pyrenaican SF-1 was obtained from the culture filtrate of the fungal isolate. The partial characterization of biochemical structure of Pyrenaican SF-1 was conducted. The fungal extract was also tested for the treatment of AGS, MDA and HeLa cell lines to assess cells proliferation, cells cycle and apoptosis. Furthermore, Pyrenaican SF-1 extract was tested for its antibacterial and antioxidant activity. Initial chemical analysis revealed that Pyrenaican SF-1 extract was composed of various monosaccharides such as d-glucose, D- mannitol, D-arabinose and ß-D-ribopyranose. In vitro study indicated that Pyrenaican SF-1 could effectively elevate percentage of apoptosis and necrosis of cancer cells and block cell cycle phase of the control group. The fungal extract could inhibit proliferation of Hela and MDA cell up to 67% and 56%, respectively. Moreover, Pyrenaican SF-1 represented a strong antioxidant activity compared to that one obtained from vitamin C. On the other hand, Pyrenaican SF-1 exhibited growth inhibitory effects against different Gram-negative and Gram-positive bacterial strains. Pyrenaican SF-1 can be considered as a bioactive macromolecule with promising application in pharmaceutical and medical sectors.

Faster automatic ASSR detection using sequential tests.

Objective: Objective Response Detection (ORD) can be used for auditory steady-state response (ASSR) detection. In conventional ORD methods, the statistical tests are applied at the end of data collection ('single-shot tests'). In sequential ORD methods, statistical tests are applied repeatedly, while data is being collected. However, repeated testing can increase False Positive (FP) rates. One solution is to infer that response is present only after the test remains significant for a predefined number of consecutive detections (NCD). Thus, this paper describes a new method for finding the required NCD that control the FP rate for ASSR detection.Design: NCD values are estimated using Monte Carlo simulations.Study sample: ASSR signals were recorded from 8 normal-hearing subjects.Results: The exam time was reduced by up to 38.9% compared to the single-shot test with loss of approximately 5% in detection rate. Alternatively, lower gains in time were achieved for a smaller (non-significant) loss in detection rate. The FP rates at the end of the test were kept at the nominal level expected (1%).Conclusion: The sequential test strategy with NCD as the stopping criterion can improve the speed of ASSR detection and prevent higher than expected FP rates.

Automated detection of auditory response: applying sequential detection strategies with constant significance level to magnitude-squared coherence.

Abstracts Objective: The detection of the auditory steady-state responses is usually performed by an appropriate objective response detector applied to stimulus-related epochs of the raw electroencephalogram (EEG). In order to improve the detection time, sequential detection strategies are usually used. These multiple tests strategies increase the probability of mistakenly detecting a response. The aim of this study was to develop strategies to determine the critical values for the sequential detection strategies based on constant significance level tests. Design: Extensive Monte Carlo simulations were used to test these strategies for the magnitude-squared coherence (MSC) detector. The performances of these strategies were compared with previous works found in the literature. Study sample: All strategies were applied to synthetic and real EEG datasets. Results: The strategies ensure the desired significance level at the end of the sequential detection strategy. The simulated results are in accordance with the real data results. Conclusions: For the MSC detector, where the critical value depends on the number of epochs, the proposed sequential detection strategies obtain better performance regarding test time and detection rate, but worse overall detection rate compared to applying a test only once.

Overcoming challenges in lignocellulosic biomass pretreatment for second-generation (2G) sugar production: emerging role of nano, biotechnological and promising approaches.

Production of green chemicals and biofuels in biorefineries is the potential alternative for petrochemicals and gasoline in transitioning of petro-economy into bioeconomy. However, an efficient biomass pretreatment process must be considered for the successful deployment of biorefineries, mainly for use of lignocellulosic raw materials. However, biomass recalcitrance plays a key role in its saccharification to obtain considerable sugar which can be converted into ethanol or other biochemicals. In the last few decades, several pretreatment methods have been developed, but their feasibility at large-scale operations remains as a persistent bottleneck in biorefineries. Pretreatment methods such as hydrodynamic cavitation, ionic liquids, and supercritical fluids have shown promising results in terms of either lignin or hemicellulose removal, thus making remaining carbohydrate fraction amenable to the enzymatic hydrolysis for clean and high amount of fermentable sugar production. However, their techno-economic feasibility at industrial scale has not been yet studied in detail. Besides, nanotechnological-based technologies could play an important role in the economically viable 2G sugar production in future. Considering these facts, in the present review, we have discussed the existing promising pretreatment methods for lignocellulosic biomass and their challenges, besides this strategic role of nano and biotechnological approaches towards the viability and sustainability of biorefineries is also discussed.

The path forward for lignocellulose biorefineries: Bottlenecks, solutions, and perspective on commercialization.

Lignocellulose biorefinery encompasses process engineering and biotechnology tools for the processing of lignocellulosic biomass for the manufacturing of bio-based products (such as biofuels, bio-chemicals, biomaterials). While, lignocellulose biorefinery offers clear value proposition, success at industrial level has not been vibrant for the commercial production of renewable chemicals and fuels. This is because of high capital and operating expenditures, irregularities in biomass supply chain, technical process immaturity, and scale up challenges. As a result, commercial production of biochemicals and biofuels with right economics is still lagging behind. To hit the market place, efforts are underway by bulk and specialty chemicals producing companies like DSM (Succinic acid, Cellulosic ethanol), Dow-DuPont (1,3-Propanediol, 1,4-Butanediol), Clariant-Global bioenergies-INEOS (bio-isobutene), Braskem (Ethylene, polypropylene), Raizen, Gran-bio and POET-DSM (Cellulosic ethanol), Amyris (Farnesene), and several other potential players. This paper entails the concept of lignocellulose biorefinery, technical challenges for industrialization of renewable fuels and bulk chemicals and future directions.

Assessment of auditory threshold using Multiple Magnitude-Squared Coherence and amplitude modulated tones monaural stimulation around 40 Hz.

BACKGROUND AND OBJECTIVE: The use of objective detection techniques applied to the auditory steady-state responses (ASSRs) for the assessment of auditory thresholds has been investigated over the years. The idea consists in setting up the audiometric profile without subjective inference from patients and evaluators. The challenge encountered is to reduce the detection time of auditory thresholds reaching high correlation coefficients between the objective and the conventional thresholds, as well as reducing difference between thresholds. METHODS: This paper evaluated the use of the Multiple Magnitude-Squared Coherence (MMSC) in Auditory Steady-State Responses (ASSRs) evoked by amplitude modulated tones around 40 Hz, attaining objective audiograms, which were, later, compared to conventional audiograms. It was proposed an analysis of the electroencephalogram signals of ten subjects, monaurally stimulated, in the intensities 15, 20, 25, 30, 40 and 50 dB SPL, for carrier frequencies of 0.5, 1, 2 and 4 kHz. After the detection protocol parameters variation, two detectors were selected according to behavioral thresholds. RESULTS: The method of this study resulted in a Maximum detector with correlation coefficient r = 0.9262, mean difference between the objective and behavioral thresholds of 6.44 dB SPL, average detection time per ear of 49.96 min and per stimulus of 2.08 min. Meanwhile, the Fast detector presented coefficient r = 0.8401, mean difference of 6.81 dB SPL, average detection time of 28.20 min per ear and 1.18 per stimulus. CONCLUSIONS: The results of this study indicate that the MMSC use in the auditory responses detection might provide a reliable and efficient estimation of auditory thresholds.

Ethanol production in a simultaneous saccharification and fermentation process with interconnected reactors employing hydrodynamic cavitation-pretreated sugarcane bagasse as raw material.

In this study, sugarcane bagasse (SCB) pretreated with alkali assisted hydrodynamic cavitation (HC) was investigated for simultaneous saccharification and fermentation (SSF) process for bioethanol production in interconnected column reactors using immobilized Scheffersomyces stipitis NRRL-Y7124. Initially, HC was employed for the evaluation of the reagent used in alkaline pretreatment. Alkalis (NaOH, KOH, Na2CO3, Ca(OH)2) and NaOH recycled black liquor (successive batches) were used and their pretreatment effectiveness was assessed considering the solid composition and its enzymatic digestibility. In SSF process using NaOH-HC pretreatment SCB, 62.33% of total carbohydrate fractions were hydrolyzed and 17.26g/L of ethanol production (0.48g of ethanol/g of glucose and xylose consumed) was achieved. This proposed scheme of HC-assisted NaOH pretreatment together with our interconnected column reactors showed to be an interesting new approach for biorefineries.

Biosurfactant production by Aureobasidium pullulans in stirred tank bioreactor: New approach to understand the influence of important variables in the process.

Surfactants are amphiphilic molecules with large industrial applications produced currently by chemical routes mainly derived from oil industry. However, biotechnological process, aimed to develop new sustainable process configurations by using favorable microorganisms, already requires investigations in more details. Thus, we present a novel approach for biosurfactant production using the promising yeast Aureobasidium pullulans LB 83, in stirred tank reactor. A central composite face-centered design was carried out to evaluate the effect of the aeration rate (0.1-1.1min-1) and sucrose concentration (20-80g.L-1) in the biosurfactant maximum tensoactivity and productivity. Statistical analysis showed that the use of variables at high levels enhanced tensoactivity, showing 8.05cm in the oil spread test and productivity of 0.0838cm.h-1. Also, unprecedented investigation of aeration rate and sucrose concentration relevance in biosurfactant production by A. pullulans in stirred tank reactor was detailed, demonstrating the importance to establish adequate conditions in bioreactors, aimed to scale-up process.

Evolution and multiple roles of the Pancrustacea specific transcription factor zelda in insects.

Gene regulatory networks (GRNs) evolve as a result of the coevolutionary processes acting on transcription factors (TFs) and the cis-regulatory modules they bind. The zinc-finger TF zelda (zld) is essential for the maternal-to-zygotic transition (MZT) in Drosophila melanogaster, where it directly binds over thousand cis-regulatory modules to regulate chromatin accessibility. D. melanogaster displays a long germ type of embryonic development, where all segments are simultaneously generated along the whole egg. However, it remains unclear if zld is also involved in the MZT of short-germ insects (including those from basal lineages) or in other biological processes. Here we show that zld is an innovation of the Pancrustacea lineage, being absent in more distant arthropods (e.g. chelicerates) and other organisms. To better understand zld´s ancestral function, we thoroughly investigated its roles in a short-germ beetle, Tribolium castaneum, using molecular biology and computational approaches. Our results demonstrate roles for zld not only during the MZT, but also in posterior segmentation and patterning of imaginal disc derived structures. Further, we also demonstrate that zld is critical for posterior segmentation in the hemipteran Rhodnius prolixus, indicating this function predates the origin of holometabolous insects and was subsequently lost in long-germ insects. Our results unveil new roles of zld in different biological contexts and suggest that changes in expression of zld (and probably other major TFs) are critical in the evolution of insect GRNs.

Hydrodynamic cavitation as an efficient pretreatment method for lignocellulosic biomass: A parametric study.

Hydrodynamic cavitation (HC), which is a highly destructive force, was employed for pretreatment of sugarcane bagasse (SCB). The efficacy of HC was studied using response surface methodology (RSM) with determining parameters varied: inlet pressure of 1-3bar, temperature of 40-70°C, and alkaline concentration of 0.1-0.3M. At the best condition (3bar, 70°C and 0.3M NaOH), 93.05% and 94.45% of hydrolysis yield of cellulose and hemicellulose, respectively, were obtained within 30min of pretreatment time. Also, pretreatment time higher than 10min had little to do regarding to SCB composition changes using different orifice plates (16 and 27 holes, with corresponding cavitation number of 0.017 and 0.048, respectively), with higher hydrolysis yield observed at 20min of process. Therefore, HC-based approach could lead to a high yield of hydrolysis, as long as a treatment condition was right; it could be so at mild conditions and at short running time.