Tangential velocity constraint for orbital maneuvers with Theory of Functional Connections.

Maneuvering a spacecraft in the cislunar space is a complex problem, since it is highly perturbed by the gravitational influence of both the Earth and the Moon, and possibly also the Sun. Trajectories minimizing the needed fuel are generally preferred in order to decrease the mass of the payload. A classical method to constrain maneuvers is mathematically modeling them using the Two Point Boundary Value Problem (TPBVP), defining spacecraft positions at the start and end of the trajectory. Solutions to this problem can then be obtained with optimization techniques like the nonlinear least squares conjugated with the Theory of Functional Connections (TFC) to embed the constraints, which recently became an effective method for deducing orbit transfers. In this paper, we propose a tangential velocity (TV) type of constraints to design orbital maneuvers. We show that the technique presented in this paper can be used to transfer a spacecraft (e.g. from the Earth to the Moon) and perform gravity assist maneuvers (e.g. a swing-by with the Moon). In comparison with the TPBVP, solving the TV constraints via TFC offers several advantages, leading to a significant reduction in computational time. Hence, it proves to be an efficient technique to design these maneuvers.

Microbiome structure in biofilms from a volcanic island in Maritime Antarctica investigated by genome-centric metagenomics and metatranscriptomics.

Antarctica is the coldest and driest continent on Earth, characterized by polyextreme environmental conditions, where species adapted form complex networks of interactions. Microbial communities growing in these harsh environments can form biofilms that help the associated species to survive and thrive. A rich body of knowledge describes environmental biofilm communities; however, most studies have focused on dominant community members rather than functional complexity and metabolic potential. To overcome these limitations, the present study used genome-centric metagenomics to describe two biofilm samples subjected to different temperature collected in Deception Island, Maritime Antarctica. The results unraveled a complex biofilm microbiome represented by 180 metagenome-assembled genomes. The potential metabolic interactions were investigated using metabolic flux balance analysis and revealed that purple bacteria are the community members with the highest correlations with other bacteria. Due to their predicted mixotrophic behavior, they may play a crucial role in the microbiome, likely supporting the heterotrophic species in biofilms. Metatranscriptomics results revealed that the chaperone system and proteins counteracting ROS and toxic compounds have a major role in maintaining bacterial cell homeostasis in sediments of volcanic origin.

Comparing resistome profiles from anthropogenically impacted and non-impacted areas of two South Shetland Islands - Maritime Antarctica.

Whalers Bay, in Deception Island, has one of the most anthropogenically impacted areas in Maritime Antarctica. However, considering the volcanic nature (high concentrations of heavy metals) of Deception Island's soils, this putative anthropogenic impact should be carefully investigated. In this context, the objective of this study was to compare resistome profiles of impacted and non-impacted areas in Deception Island (Whalers Bay, Crater Lake, and Fumarole Bay) and Livingston Island (Hannah Point) in order to investigate the microbiome tolerance/resistance mechanisms selected as a function of environmental drivers. Metagenomics was used to search for genes conferring resistance/tolerance to antibiotics, biocides, and heavy metals. Whalers Bay has a greater diversity of antibiotic, biocide, and heavy metal resistance classes found in its microbiomes. However, Hannah Point, at Livingston Island, has a greater abundance of antibiotic and biocide resistance/tolerance genes. The microbiome of Deception Island's non-impacted areas (Crater Lake and Fumarole Bay) showed resistance/tolerance genes almost entirely to heavy metals. Pb was found in higher concentrations in Whalers Bay soil in comparison to the other areas, indicating human contamination. The non-metric multidimensional scaling (NMDS) analysis revealed that Pb concentrations influenced resistome profiles in Whalers Bay soil. Despite the effect of Pb on the microbial communities of Whalers Bay, most heavy metal concentrations did not have a significant impact on resistome genes, suggesting that the volcanic soil heavy metal concentration of Deception Island has little biological influence.

Dynamics of microbial stress responses driven by abiotic changes along a temporal gradient in Deception Island, Maritime Antarctica.

Whalers Bay (WB), Deception Island, is an environment that can drastically change its temperature within a few meters. The main forms of life inhabiting this environment are microorganisms, which, due to the high diversity and their adaptive potential, can survive and thrive under harsh stress conditions. However, the genetic potential and mechanisms to cope with fluctuating adverse conditions as well as what extent environmental variations shape the microbial community over the years it is still unknown in Antarctic environments. In this work, sediments collected in a transect in Whalers Bay, Deception Island, during the Austral Summers of 2014, 2015 and 2017 were analyzed using shotgun metagenomics. Sequence data were further processed with the SqueezeMeta tool for assembly, gene prediction, mapping, taxonomic and functional annotations. Results showed that stress-related functions had the influence of temperatures and solar radiation observed in the years of 2015 and 2017. The most differentiated functions were the ones related to oxidative stress, comparing 2014 vs 2015 and 2014 vs 2017. The genes coding for HSP20 and oxidoreductases (nrdH, grxA, korC and korD), as well as the genes clpE, cspL, and operons mtrAB and vicKR, were differentially enriched between the years, most of them found in gram-positive bacteria. The selective pressures of temperature and radiation may have favored the growth of gram-positive bacteria in 2017, with emphasis on Arthrobacter genus. Data gathered in this work showed that temperature and solar radiation could potentially be the primary driving forces shaping the repertoire of stress-response genes for the maintenance of microbial diversity in WB Antarctic sediments.

Microbiome taxonomic and functional profiles of two domestic sewage treatment systems.

Anaerobic systems for domestic sewage treatment, like septic tanks and anaerobic filters, are used in developing countries due to favorable economic and functional features. The anaerobic filter is used for the treatment of the septic tank effluent, to improve the COD removal efficiency of the system. The microbial composition and diversity of the microbiome from two wastewater treatment systems (factory and rural school) were compared through 16S rRNA gene sequencing using MiSeq 2 × 250 bp Illumina sequencing platform. Additionally, 16S rRNA data were used to predict the functional profile of the microbial communities using PICRUSt2. Results indicated that hydrogenotrophic methanogens, like Methanobacterium, were found in higher abundance in both systems compared to acetotrophic methanogens belonging to Methanosaeta genus. Also, important syntrophic microorganisms (Smithella, Syntrophus, Syntrophobacter) were found in the factory and rural school wastewater treatment systems. Microbial communities were also compared between stages (septic tank and anaerobic filter) of each wastewater treatment stage, revealing that, in the case of the rural school, both microbial communities were quite similar most likely due to hydraulic short-circuit issues. Meanwhile, in the factory, microbial communities from the septic tank and anaerobic filter were different. The school system showed lower COD removal rates (2-30%), which were probably related to a higher abundance of Firmicutes members in addition to the hydraulic short-circuit and low abundance of Chloroflexi members. On the other hand, the fiberglass factory presented higher COD removal rates (60-83%), harboring phyla reported as the core microbiome of anaerobic digesters (Bacteroidetes, Chloroflexi, and Proteobacteria phyla). The knowledge of the structure and composition of wastewater treatment systems may provide support for the improvement of the pollutant removal in anaerobic process.

Taxonomic and functional diversity of the microbiome in a jet fuel contaminated site as revealed by combined application of in situ microcosms with metagenomic analysis.

Natural attenuation represents all processes that govern contaminant mass removal, which mainly occurs via microbial degradation in the environment. Although this process is intrinsic its rate and efficiency depend on multiple factors. This study aimed to characterize the microbial taxonomic and functional diversity in different aquifer sediments collected in the saturated zone and in situ microcosms (BACTRAP®s) amended with hydrocarbons (13C-labeled and non-labeled benzene, toluene and naphthalene) using 16S rRNA gene and "shotgun" Illumina high throughput sequencing at a jet-fuel contaminated site. The BACTRAP®s were installed to assess hydrocarbon metabolism by native bacteria. Results indicated that Proteobacteria, Actinobacteria and Firmicutes were the most dominant phyla (~98%) in the aquifer sediment samples. Meanwhile, in the benzene- and toluene-amended BACTRAP®s the phyla Firmicutes and Proteobacteria accounted for about 90% of total community. In the naphthalene-amended BACTRAP®, members of the SR-FBR-L83 family (Order Ignavibacteriales) accounted for almost 80% of bacterial community. Functional annotation of metagenomes showed that only the sediment sample located at the source zone border and with the lowest BTEX concentration, has metabolic potential to degrade hydrocarbons aerobically. On the other hand, in situ BACTRAP®s allowed enrichment of hydrocarbon-degrading bacteria. Metagenomic data suggest that fumarate addition is the main mechanism for hydrocarbon activation of toluene. Also, indications for methylation, hydroxylation and carboxylation as activation mechanisms for benzene anaerobic conversion were found. After 120 days of exposure in the contaminated groundwater, the isotopic analysis of fatty acids extracted from BACTRAP®s demonstrated the assimilation of isotopic labeled compounds in the cells of microbes expressed by strong isotopic enrichment. We propose that the microbiota in this jet-fuel contaminated site has metabolic potential to degrade benzene and toluene by a syntrophic process, between members of the families Geobacteraceae and Peptococcaceae (genus Pelotomaculum), coupled to nitrate, iron and/or sulfate reduction.

Unveiling resistome profiles in the sediments of an Antarctic volcanic island.

The Deception Island, located in Maritime Antarctica, is a volcanic island with geothermal activity and one of the most visited by tourists. However, the extent of the anthropogenic impact remains largely unknown and the factors shaping the resistance/tolerance mechanisms in the microbiomes from Whalers Bay ecosystems have never been investigated. In this context, this study aimed to reveal the resistome profiles of Whalers Bay sediments and correlate them with environmental factors. Samples were collected at four sites during the summer 2014/2015 along a transect of 27.5 m in the Whalers Bay sediments. DNA isolated from sediment samples was sequenced using the Illumina HiSeq platform. Bioinformatic analyses allowed the assembly of contigs and scaffolds, prediction of ORFs, and taxonomic and functional annotation using NCBI RefSeq database and KEGG orthology, respectively. Microorganisms belonging to the genera Psychrobacter, Flavobacterium and Polaromonas were shown to dominate all sites, representing 60% of taxonomic annotation. Arsenic (As), copper (Cu) and iron (Fe) were the most abundant metal resistance/tolerance types found in the microbiomes. Beta-lactam was the most common class related to antibiotics resistance/tolerance, corroborating with previous environmental resistome studies. The acridine class was the most abundant amongst the biocide resistance/tolerances, related to antiseptic compounds. Results gathered in this study reveal a repertoire of resistance/tolerance classes to antibiotics and biocides unusually found in Antarctica. However, given the volcanic nature (heavy metals-rich region) of Deception Island soils, this putative impact must be viewed with caution.

Laundry wastewater and domestic sewage pilot-scale anaerobic treatment: Microbial community resilience regarding sulfide production.

In this study, the removal of anionic surfactant Linear Alkylbenzene Sulfonate (LAS) from laundry wastewater was evaluated in co-digestion with domestic sewage, using a pilot-scale Expanded Granular Sludge Bed reactor. Surfactant influent concentration was enhanced from 5 ±â€¯3 mg LAS L-1 (stage I) to 19 ±â€¯10 mg LAS L-1 (stage II) and 36 ±â€¯19 mg LAS L-1 (stage III) throughout reactor operation. Sulfide levels higher than 20 mg L-1 influenced LAS removal efficiency, which decreased from 71% to 55% and 32% in stage I, II and III, respectively. Acclimation of microbial population was verified and higher relative abundance of the genera similar to Cytophaga, Bacteroides, Syntrophus and Syntrophobacter in the early stages (adaptation and stage I) was replaced by higher relative abundance of the genera Anaerophaga, Nitrosovibrio, Sulfurovum and Desulfovibrio in the last stages (stage II and III).

Black and white teas as potential agents to combine with amphotericin B and protect red blood cells from amphotericin B-mediated toxicity / Chá preto e branco de Camellia sinensis como potenciais agentes para associar com anfotericina B

Abstract Amphotericin B is a fungicidal substance that is treatment of choice for most systemic fungal infections affecting immunocompromised patients. However, severe side effects have limited the utility of this drug. The aim of this study was to evaluate the antifungal effect of the combination of amphotericin B with black tea or white tea and protective of citotoxic effect. The present study shows that white and black teas have additive effects with amphotericin B against some species Candida. In addition, the combination of white and black tea with amphotericin B may reduce the toxicity of amphotericin B to red blood cells. Our results suggest that white and black tea is a potential agent to combine with amphotericin for antifungal efficacy and to reduce the amphotericin dose to lessen side effects.

Resumo A anfotericina B é o tratamento de escolha para a maioria das infecções fúngicas sistémicas que afetam os doentes imunocomprometidos. No entanto, efeitos secundários graves têm limitado a utilidade desta droga. O objetivo deste estudo foi avaliar o efeito antifúngico da combinação de anfotericina B com chá preto ou chá branco, bem como o efeito citotóxico desta combinação sobre hemáceas. O presente estudo demonstra que o chá branco e preto de Camellia sinensis têm efeitos aditivos com anfotericina B contra algumas espécies de Candida sp. Além disso, a combinação de chá branco e preto com anfotericina B pode reduzir a toxicidade da anfotericina B em hemáceas. Nossos resultados sugerem que o chá branco e preto são agentes potenciais para associação com anfotericina B contribuindo para eficácia antifúngica, bem como redução de toxicidade.

Black and white teas as potential agents to combine with amphotericin B and protect red blood cells from amphotericin B-mediated toxicity.

Amphotericin B is a fungicidal substance that is treatment of choice for most systemic fungal infections affecting immunocompromised patients. However, severe side effects have limited the utility of this drug. The aim of this study was to evaluate the antifungal effect of the combination of amphotericin B with black tea or white tea and protective of citotoxic effect. The present study shows that white and black teas have additive effects with amphotericin B against some species Candida. In addition, the combination of white and black tea with amphotericin B may reduce the toxicity of amphotericin B to red blood cells. Our results suggest that white and black tea is a potential agent to combine with amphotericin for antifungal efficacy and to reduce the amphotericin dose to lessen side effects.

Metagenomic analysis of the microbiome in three different bioreactor configurations applied to commercial laundry wastewater treatment.

The taxonomic and functional diversity of three different biological reactors (fluidized bed reactor, FBR; up-flow anaerobic sludge blanket reactor, UASB; and expanded granular sludge bed reactor, EGSB) used for commercial laundry wastewater treatment was investigated using metagenome shotgun sequencing. Metagenomes were sequenced on the Illumina Hiseq platform and were analyzed using MG-RAST, STAMP and PAST software. The EGSB and UASB reactors were more closely related based on taxonomic and functional profiles, likely due to similar granular sludge and procedures adopted to ensure anaerobic conditions. The EGSB and UASB reactors showed a predominance of methanogens and genes related to methanogenesis, with a prevalence of the acetoclastic pathway, in addition to the peripheral and central O2-independent pathways for aromatic compound degradation. By contrast, FBR showed a dominance of aerobic microbiota and pathways for O2-dependent aromatic compound degradation. Therefore, although the reactors showed similar surfactant removal levels, the microbial composition, functional diversity and aromatic compound degradation pathways were significantly distinct.

Quercetin and rutin as potential agents antifungal against Cryptococcus spp / Quercetina e rutina: potenciais agentes para terapia antifúngica

Abstract Amphotericin B is a fungicidal substance that is treatment of choice for most systemic fungal infections affecting as cryptococcosis the immunocompromised patients. However, severe side effects have limited the utility of this drug. The aim of this study was to evaluate the antifungal effect of the combination of amphotericin B with quercetin or rutin and as a protective of citotoxic effect. The antifungal activity to amphotericin B, quercetin and rutin alone and in combination was determined in Candida sp and Cryptococcus neoformans strains. Cytotoxicity test on erythrocytes was performed by spectrophotometric absorbance of hemoglobin. The amphotericin B MIC was reduced when used in combination with quercetin or rutin to C. neoformans ATCC strain and reduced when combined with rutin to a clinical isolate of C. neoformans. In addition, the combination of quercetin with amphotericin B may reduce the toxicity of amphotericin B to red blood cells. Our results suggest that quercetin and rutin are potential agents to combine with amphotericin B in order to reduce the amphotericin dose to lessen side effects and improve antifungal efficacy.

Resumo A anfotericina B é uma substância fungicida e é o tratamento de escolha para a maioria das infecções fúngicas sistêmicas que afetam os pacientes imunocomprometidos, como a criptococose. No entanto, as severas reações adversas têm limitado a utilização desta droga. O objetivo deste estudo foi avaliar o efeito antifúngico e o potencial efeito protetor de citotoxicidade da combinação de anfotericina B com quercetina ou rutina. A atividade antifúngica de anfotericina B, quercetina e rutina, isoladamente e em combinação foi determinada em cepas de Candida sp e Cryptococcus neoformans. O teste de citotoxicidade em eritrócitos foi realizado por espectrofotometria, através da determinação da absorbância da hemoglobina. A concentração inibitória mínima da anfotericina B foi reduzida quando utilizada em combinação com a quercetina e rutina em C. neoformans ATCC e reduzida quando combinados com rutina em um isolado clínico de C. neoformans. Além disso, a combinação de quercetina com anfotericina B pode reduzir a toxicidade da droga em eritrócitos. Os resultados sugerem que quercetina e rutina são potenciais agentes para combinação com anfotericina B, a fim de reduzir a dose de anfotericina, diminuindo os efeitos colaterais e melhorando sua eficácia antifúngica.

Valor prognóstico da variabilidade da frequência cardíaca e da eletrocardiografia ambulatorial em cães Boxer com cardiomiopatia arritmogênica do ventrículo direito / Prognostic value of heart rate variability and Holter monitoring in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy

A cardiomiopatia arritmogênica do ventrículo direito (CAVD) é uma importante causa de morte súbita em cães da raça Boxer. A validação de fatores prognósticos para essa doença auxiliaria na detecção de animais mais gravemente afetados e sua exclusão dos programas de reprodução. O objetivo deste estudo foi avaliar o valor prognóstico da presença de manifestações clínicas, dos índices de variabilidade de frequência cardíaca (VFC) e das arritmias supraventriculares ou ventriculares registradas à monitorização eletrocardiográfica com Holter na sobrevida de cães Boxer em diferentes estágios da CAVD. Essas variáveis foram analisadas, de forma prospectiva, em 69 cães Boxer, divididos em cinco grupos: cães Boxer controle (grupo CB, <50 VPC/24 horas, n=28), cães Boxer suspeitos (grupo SB, 50 a 300 VPC/24 horas, n=8), cães Boxer com CAVD (grupo ARVC, >300 VPC/24 horas, n=19), cães Boxer com CAVD e disfunção sistólica sem insuficiência cardíaca congestiva (grupo SDB sem ICC, n=6) e com ICC (grupo SDB com ICC, n=8). A análise estatística compreendeu teste ANOVA, correlação de Pearson e análise de riscos proporcionais de Cox. Comparando-se com o grupo CB, não foi encontrada diminuição nos índices de VFC nos grupos SB, ARVC ou SDB sem ICC; por outro lado, o grupo SDB com ICC apresentou diminuição desses índices. Não houve relação entre os índices de VFC e a morte de origem cardíaca; porém, a presença de síncopes com ou sem sinais clínicos de ICC e o número de episódios de taquicardia ventricular (TV) correlacionaram-se com a sobrevida dos animais. Estes resultados permitem concluir que a presença de sinais clínicos de ICC, a presença de síncopes e o número de TV ao Holter apresentam valor prognóstico de sobrevida em cães Boxer com CAVD.(AU)

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an important cause of sudden death in Boxer dogs. Validation of prognostic factors for this disease could help in detecting more severely affected animals and their exclusion from breeding programs. The aims of this study were to evaluate the prognostic significance of presence of symptoms, heart rate variability (HRV) indices and ventricular or supraventricular arrhythmias recorded by Holter monitoring on survival of Boxer dogs with ARVC at different stages. Symptoms, arrhythmias registered on Holter and five HRV indices were prospectively analyzed in 69 client-owned Boxer dogs divided into five groups: control Boxer dogs (CB group, <50 VPC/24 hours, n=28), suspicious Boxers (SB group, 50 to 300 VPC/24 hours, n=8), Boxers with ARVC (ARVC group, >300 VPC/24 hours, n=19), Boxers with ARVC and systolic dysfunction without congestive heart failure (SDB without CHF group, n=6) and with CHF (SDB with CHF group, n=8). Statistical analyses consisted of an ANOVA test, Pearson correlation and Cox's proportional hazards regression. Compared to the CB group, no decrease in HRV indices was found in SB, ARVCB or SDB without CHF groups; otherwise, SDB with CHF group had impaired indices. No relation was found between HRV indices and cardiac-related death, but the presence of syncopes with or without clinical signs of heart failure and number of ventricular tachycardia (VT), were correlated with survival. These results allow us to conclude that the presence of symptoms of heart failure, presence of syncopes and number of VT on Holter examination seem to have prognostic value in Boxer ARVC.(AU)

Lactobacillus is able to alter the virulence and the sensitivity profile of Candida albicans.

AIMS: The study investigated whether the interaction with Lactobacillus rhamnosus (ATCC7469) interfere with the expression of virulence factors by Candida albicans (ATCC18804). METHODS AND RESULTS: These micro-organisms were grown in biofilms for 24, 48 and 72 h, Candida was isolated and the expression of the major virulence factors were investigated. The production of phospholipase, protease and haemolysin were observed in appropriate media; observation of germ tubes formation in serum; biofilm formation, after growth in microtitre plates and reading in spectrophotometer. Candida was also tested for antifungal sensitivity to amphotericin B, fluconazole and ketoconazole. The results were compared with the cells of Candida grown in the absence of lactobacilli (control group). Candida cells, which interacted with Lact. rhamnosus (test group), showed significantly lower proteinase and haemolysin activity, when compared with control group. The germ tube formation and biofilm formation capacity also decreased in tested groups, which demonstrated alterations in susceptibility to antifungal drugs. CONCLUSIONS: The results suggest that Lact. rhamnosus is able to influence the expression of virulence factors by C. albicans and can alter its antifungal sensitivity profile. SIGNIFICANCE AND IMPACT OF THE STUDY: These results suggest reduction in the pathogenicity of Candida and improvement in candidiasis therapy and control.

Bioaugmentation strategy employing a microbial consortium immobilized in chitosan beads for oil degradation in mesocosm scale.

A bacterial consortium composed by four metagenomic clones and Bacillus subtilis strain CBMAI 707, all derived from petroleum reservoirs, was entrapped in chitosan beads and evaluated regarding hydrocarbon degradation capability. Experiments were carried out in mesocosm scale (3000L) with seawater artificially polluted with crude oil. At different time intervals, mesocosms were sampled and subjected to GC-FID and microbiological analyses, as total and heterotrophic culturable bacterial abundance (DAPI and CFU count), biological oxygen demand (BOD) and taxonomic diversity (massive sequencing of 16S rRNA genes). The results obtained showed that degradation of n-alkane hydrocarbons was similar between both treatments. However, aromatic compound degradation was more efficient in bioaugmentation treatment, with biodegradation percentages reaching up to 99% in 30days. Community dynamics was different between treatments and the consortium used in the bioaugmentation treatment contributed to a significant increase in aromatic hydrocarbon degradation.

Quercetin and rutin as potential agents antifungal against Cryptococcus spp.

Amphotericin B is a fungicidal substance that is treatment of choice for most systemic fungal infections affecting as cryptococcosis the immunocompromised patients. However, severe side effects have limited the utility of this drug. The aim of this study was to evaluate the antifungal effect of the combination of amphotericin B with quercetin or rutin and as a protective of citotoxic effect. The antifungal activity to amphotericin B, quercetin and rutin alone and in combination was determined in Candida sp and Cryptococcus neoformans strains. Cytotoxicity test on erythrocytes was performed by spectrophotometric absorbance of hemoglobin. The amphotericin B MIC was reduced when used in combination with quercetin or rutin to C. neoformans ATCC strain and reduced when combined with rutin to a clinical isolate of C. neoformans. In addition, the combination of quercetin with amphotericin B may reduce the toxicity of amphotericin B to red blood cells. Our results suggest that quercetin and rutin are potential agents to combine with amphotericin B in order to reduce the amphotericin dose to lessen side effects and improve antifungal efficacy.

Selection for wide adaptability and high phenotypic stability of Brazilian soybean genotypes.

Advances in genetic enhancement techniques have led to an increase in soybean production. Thus, soybean is currently one the most economically important cultured species worldwide. The objectives of the present study were to study the interaction of soybean genotypes per environment in terms of grain productivity and to evaluate their phenotypic adaptability and stability, with the final aim of selecting lineages with high productivity, wide adaptability, and high stability. Seven soybean genotypes, consisting of five lineages developed by the soybean genetic enhancement program of the Universidade Federal de Uberlândia (Brazil) and two controls, were evaluated during several annual cycles in seven different environments. A randomized complete block design (RCBD) with three replicates was adopted in each site. This study followed the methodology proposed by Eberhart and Russel and Lin and Binns, with modifications by Carneiro, and the AMMI (additive main effects and multiplicative interaction model) analysis. The average productivity of soybean cultivars in the trials was 2739.26 kg/ha. The L01V13 genotype and the UFUS Guarani cultivar had wide adaptation according to the methodology proposed by Eberhart and Russel and Lin and Binns, with modifications by Carneiro. When analyzed with the AMMI model, the UFUS Guarani cultivar showed high stability. In general, the methodologies studied are complementary and, when used together, increase the reliability of the classification, providing support for the use of specific soybean cultivars in different environments.

Evaluation of soybean lines and environmental stratification using the AMMI, GGE biplot, and factor analysis methods.

In the final phases of new soybean cultivar development, lines are cultivated in several locations across multiple seasons with the intention of identifying and selecting superior genotypes for quantitative traits. In this context, this study aimed to study the genotype-by-environment interaction for the trait grain yield (kg/ha), and to evaluate the adaptability and stability of early-cycle soybean genotypes using the additive main effects and multiplicative interaction (AMMI) analysis, genotype main effects and genotype x environment interaction (GGE) biplot, and factor analysis methods. Additionally, the efficiency of these methods was compared. The experiments were carried out in five cities in the State of Mato Grosso: Alto Taquari, Lucas do Rio Verde, Sinop, Querência, and Rondonópolis, in the 2011/2012 and 2012/2013 seasons. Twenty-seven early-cycle soybean genotypes were evaluated, consisting of 22 lines developed by Universidade Federal de Uberlândia (UFU) soybean breeding program, and five controls: UFUS Carajás, MSOY 6101, MSOY 7211, UFUS Guarani, and Riqueza. Significant and complex genotype-by-environment interactions were observed. The AMMI model presented greater efficiency by retaining most of the variation in the first two main components (61.46%), followed by the GGE biplot model (57.90%), and factor analysis (54.12%). Environmental clustering among the methodologies was similar, and was composed of one environmental group from one location but from different seasons. Genotype G5 presented an elevated grain yield, and high adaptability and stability as determined by the AMMI, factor analysis, and GGE biplot methodologies.

Production and properties of a surface-active lipopeptide produced by a new marine Brevibacterium luteolum strain.

Microbial-derived surfactants are molecules of great interest due to their environmentally friendly nature and low toxicity; however, their production cost is not competitive when compared to synthetics. Marine microorganisms are exposed to extremes of pressure, temperature, and salinity; hence, they can produce stable compounds under such conditions that are useful for industrial applications. A screening program to select marine bacteria able to produce biosurfactant using low-cost substrates (mineral oil, sucrose, soybean oil, and glycerol) was conducted. The selected bacterial strain showed potential to synthesize biosurfactants using mineral oil as carbon source and was identified as Brevibacterium luteolum. The surface-active compound reduced the surface tension of water to 27 mN m(-1) and the interfacial tension (water/hexadecane) to 0.84 mN m(-1) and showed a critical micelle concentration of 40 mg L(-1). The biosurfactant was stable over a range of temperature, pH, and salt concentration and the emulsification index (E24) with different hydrocarbons ranging from 60 to 79 %. Structural characterization revealed that the biosurfactant has a lipopeptide nature. Sand washing removed 83 % of crude oil demonstrating the potential of the biosurfactants (BS) for bioremediation purposes. The new marine B. luteolum strain showed potential to produce high surface-active and stable molecule using a low-cost substrate.

Adsorption of pH-responsive polyelectrolyte chains onto spherical macroions.

The adsorption of pH-responsive polyelectrolyte chains onto oppositely charged spherical macroions is investigated through Metropolis Monte Carlo simulations and the Weighted Histogram Analysis Method. In this case, the polymer charge density is susceptible to the solution conditions, such as salt concentration and pH, as well as the presence of other charged species. Thus, the pH and ionic strength variations leads to abrupt variations of the conformational and electric properties of the chain, as a result of first-order-like transition between the adsorbed and desorbed states. The diagram of states as a function of ionic strenght and p H is provided. Despite the inhomogeneities in the polyelectrolyte charge distribution induced by the macroion presence and its dependence on ionic strength, the scaling relation between the macromolecular charge densities and the critical Debye length is obtained in agreement with experimental investigations.