How the vertical gradient of light in the understorey and water seasonality affect leaf traits of Vanilla phaeantha (Orchidaceae), a crassulacean acid metabolism (CAM) hemiephyte.

Structural and physiological leaf traits and their plasticity were compared in the hemiepiphyte Vanilla phaeantha . This species grows along a phorophyte reaching different understorey positions and exhibiting diverse responses to environment changes. We analysed three height strata above the ground, establishing a light gradient, and considering seasonal water fluctuations. The upper leaves had higher area and mass and were less pigmented. The dry season induced a reduction of approximately 2h of stomatal opening over the diel 24h crassulacean acid metabolism (CAM) cycle in the leaves at all understorey positions. The leaves more exposed to sunlight were larger with higher titratable acidity during the rainy season, while the leaves near the ground maintained the same rates of stomatal conductance and nocturnal acidification between seasons, with lowest values of carbon isotopes in the rainy season. Our research showed that some structural leaf traits (such as specific leaf mass, biomass, and saturated water content) are sensitive to variation in understorey position. In contrast, other physiological traits (stomatal conductance, transpiration, and fluorescence parameters) are more sensitive to seasonal variations. The results are a novelty in assessing the variation of CAM along the same plant in a height gradient and under field conditions.

Comparison of the precursor, amino acid oxidation, and end-product methods for the evaluation of protein turnover in senior dogs.

Stable isotope methods have been used to study protein metabolism in humans; however, there application in dogs has not been frequently explored. The present study compared the methods of precursor (13C-Leucine), end-products (15N-Glycine), and amino acid oxidation (13C-Phenylalanine) to determine the whole-body protein turnover rate in senior dogs. Six dogs (12.7 ± 2.6 years age, 13.6 ± 0.6 kg bodyweight) received a dry food diet for maintenance and were subjected to all the above-mentioned methods in succession. To establish 13C and 15N kinetics, according to different methodologies blood plasma, urine, and expired air were collected using a specifically designed mask. The volume of CO2 was determined using respirometry. The study included four methods viz. 13C-Leucine, 13C-Phenylalanine evaluated with expired air, 13C-Phenylalanine evaluated with urine, and 15N-Glycine, with six dogs (repetitions) per method. Data was subjected to variance analysis and means were compared using the Tukey test (P<0.05). In addition, the agreement between the methods was evaluated using Pearson correlation and Bland-Altman statistics. Protein synthesis (3.39 ± 0.33 g.kg-0,75. d-1), breakdown (3.26 ± 0.18 g.kg-0.75.d-1), and flux estimations were similar among the four methods of study (P>0.05). However, only 13C-Leucine and 13C-Phenylalanine (expired air) presented an elevated Pearson correlation and concordance. This suggested that caution should be applied while comparing the results with the other methodologies.

Influence of CReatine supplementation on mUScle mass and strength after stroke (ICaRUS Stroke Trial): study protocol for a randomized controlled trial.

BACKGROUND: Stroke is a leading cause of mortality and disability, and its sequelae are associated with inadequate food intake which can lead to sarcopenia. The aim of this study is to verify the effectiveness of creatine supplementation on functional capacity, strength, and changes in muscle mass during hospitalization for stroke compared to usual care. An exploratory subanalysis will be performed to assess the inflammatory profiles of all participants, in addition to a follow-up 90 days after stroke, to verify functional capacity, muscle strength, mortality, and quality of life. METHODS: Randomized, double-blind, unicenter, parallel-group trial including individuals with ischemic stroke in the acute phase. The duration of the trial for the individual subject will be approximately 90 days, and each subject will attend a maximum of three visits. Clinical, biochemical, anthropometric, body composition, muscle strength, functional capacity, degree of dependence, and quality of life assessments will be performed. Thirty participants will be divided into two groups: intervention (patients will intake one sachet containing 10g of creatine twice a day) and control (patients will intake one sachet containing 10g of placebo [maltodextrin] twice a day). Both groups will receive supplementation with powdered milk protein serum isolate to achieve the goal of 1.5g of protein/kg of body weight/day and daily physiotherapy according to the current rehabilitation guidelines for patients with stroke. Supplementation will be offered during the 7-day hospitalization. The primary outcomes will be functional capacity, strength, and changes in muscle mass after the intervention as assessed by the Modified Rankin Scale, Timed Up and Go test, handgrip strength, 30-s chair stand test, muscle ultrasonography, electrical bioimpedance, and identification of muscle degradation markers by D3-methylhistidine. Follow-up will be performed 90 days after stroke to verify functional capacity, muscle strength, mortality, and quality of life. DISCUSSION: The older population has specific nutrient needs, especially for muscle mass and function maintenance. Considering that stroke is a potentially disabling event that can lead the affected individual to present with numerous sequelae, it is crucial to study the mechanisms of muscle mass loss and understand how adequate supplementation can help these patients to better recover. TRIAL REGISTRATION: The Brazilian Clinical Trials Registry (ReBEC) RBR-9q7gg4 . Registered on 21 January 2019.

Conceptual model of a semi-arid coastal aquifer using hydrogeochemical seasonal variation and isotopic fingerprints in Tamoios, Rio de Janeiro, Brazil.

The present study focuses on the Tamoios aquifer (Rio de Janeiro State, Brazil), which is under pressure due to receiving a significant volume of urban runoff and sewage. The objective was based on a number of hydrogeochemical and isotope data to assess the aquifer functioning and establishing a conceptual model to evaluate the hydrogeochemical processes. The database consisted of groundwater samples (n = 20) and surface water samples (fluvial, lagoon, and seawater) (n = 4), analyzed for major and trace constituents plus 18O and 2H isotopes. Results demonstrate that most of the groundwater samples were classified as sodium-chloride type in the rainy season and magnesium-chloride type in the dry season. Ion ratios indicated the ion sources and chemical behavior. Groundwater remained with a relatively high salt content throughout the seasons, particularly in the samples from the southern portion of the aquifer. PHREEQC software simulations exposed dolomite and calcite in mostly undersaturated condition and halite subsaturated throughout the year. Hydrogeochemical behavior indicated the salt content in the groundwater was not related to a hypothetical saltwater intrusion and revealed a steady state condition for the groundwater interface. Groundwater samples have a similar isotopic signature and were likely influenced by evaporative effects, indicating a role for the existing ponds in aquifer recharge. Strong free surface evaporation effects, evapotranspiration, and drainage processes in the floodplains probably enhanced the high ionic concentration in the groundwater environment.

Prevalence of Helicobacter pylori infection among asymptomatic children in southeastern Brazil: a cross-sectional study

ABSTRACT BACKGROUND: The prevalence of Helico bacter pylori (H. pylori) infection is decreasing worldwide, but is still high in developing countries. We previously observed an H. pylori infection rate of 52% among children and adolescents with chronic non-ulcer dyspepsia. OBJECTIVE: To investigate the prevalence of H. pylori infection among asymptomatic children living in a single region and to evaluate the risk factors for this infection. DESIGN AND SETTING: Cross-sectional study in which 161 children aged 5-13 years (mean age 7.8 years), at a public school in Botucatu, state of São Paulo, southeastern Brazil, were assessed. METHOD: The children's H. pylori infection status was determined through the urea breath test and the risk factors for acquisition of the infection were determined based on a sociodemographic questionnaire. RESULTS: The overall prevalence of H. pylori infection was 20.5%: 18.7% among females and 22.2% among males. The results from the sociodemographic survey did not differ between children with and without H. pylori infection. 30.9% of the children had previous records of upper gastrointestinal symptoms, which consisted of H. pylori infection in only 26.5% of these cases. Family histories of gastritis and peptic ulcer disease were found in relation to 50% and 32.3% of the children with H. pylori infection respectively. CONCLUSION: The prevalence of H. pylori infection among asymptomatic children in southeastern Brazil is lower than that recorded among symptomatic children in the same region and similar to the prevalence of H. pylori infection observed in developed countries.

Prevalence of Helicobacter pylori infection among asymptomatic children in southeastern Brazil: a cross-sectional study.

BACKGROUND: The prevalence of Helico bacter pylori (H. pylori) infection is decreasing worldwide, but is still high in developing countries. We previously observed an H. pylori infection rate of 52% among children and adolescents with chronic non-ulcer dyspepsia. OBJECTIVE: To investigate the prevalence of H. pylori infection among asymptomatic children living in a single region and to evaluate the risk factors for this infection. DESIGN AND SETTING: Cross-sectional study in which 161 children aged 5-13 years (mean age 7.8 years), at a public school in Botucatu, state of São Paulo, southeastern Brazil, were assessed. METHOD: The children's H. pylori infection status was determined through the urea breath test and the risk factors for acquisition of the infection were determined based on a sociodemographic questionnaire. RESULTS: The overall prevalence of H. pylori infection was 20.5%: 18.7% among females and 22.2% among males. The results from the sociodemographic survey did not differ between children with and without H. pylori infection. 30.9% of the children had previous records of upper gastrointestinal symptoms, which consisted of H. pylori infection in only 26.5% of these cases. Family histories of gastritis and peptic ulcer disease were found in relation to 50% and 32.3% of the children with H. pylori infection respectively. CONCLUSION: The prevalence of H. pylori infection among asymptomatic children in southeastern Brazil is lower than that recorded among symptomatic children in the same region and similar to the prevalence of H. pylori infection observed in developed countries.

Tryptophan and Biogenic Amines in the Differentiation and Quality of Honey.

Honey is a natural product with beneficial properties to health and has different characteristics depending on the region of production and collection, flowering, and climate. The presence of precursor amino acids of- and biogenic amines can be important in metabolomic studies of differentiation and quality of honey. We analyzed 65 honeys from 11 distinct regions of the State of Santa Catarina (Brazil) as to the profile of amino acids and biogenic amines by HPLC. The highest L-tryptophan (Trp), 5-hydroxytryptophan (5-OH-Trp), and tryptamine (Tryp) levels were detected in Cfb climate and harvested in 2019. Although we have found high content of serotonin, dopamine, and L-dopa in Cfb climate, the highest values occurred in honey produced during the summer 2018 and at altitudes above 900 m. Results indicate that the amino acids and biogenic amine levels in honeys are good indicators of origin. These data warrant further investigation on the honey as source of amino acids precursor of serotonin, melatonin, and dopamine, what can guide the choice of food as source of neurotransmitters.

Odd-chain fatty acids as an alternative method to predict ruminal microbial nitrogen flow of feedlot Nellore steers fed grain-based diets supplemented with different nitrogen sources.

This study aimed to evaluate the use of total odd-chain fatty acids (OCFA) as a marker to estimate microbial nitrogen flow (MicN) and calculate the efficiency of microbial nitrogen synthesis (EMNS) in Nellore steers fed high-concentrate diets supplemented with different nitrogen supplements (NS). Ruminally and duodenally cannulated Nellore steers (n = 6; 354 ± 12 kg) were used in a 6 × 6 repeated switchback design balanced for residual effects. Treatments were arranged in a 3 × 3 factorial of three nitrogen (N) supplements (urea plus soybean meal; corn gluten meal; dried distillers' grains plus solubles) and three microbial markers (OCFA; double-labeled urea, 15N; microbial nucleic acid bases, MNAB). The total mixed ration was composed of fresh chopped sugarcane as the forage source in an 83:17 concentrate: forage ratio (dry matter basis). Linear regression was used to develop predictions of MicN from OCFA using 15N and MNAB as response variables. Microbial N flow was underestimated by the MNAB marker compared to 15N. Neither NS nor their respective interactions with the marker methods (MM) affected MicN or EMNS (P > 0.05). However, MicN was different for 15N and MNAB (P > 0.001 for both treatments). Marker methods affected EMNS in all energetic bases (total digestible carbohydrates P < 0.001; rumen-fermentable carbohydrates P < 0.001; organic matter truly degradable in the rumen P < 0.001). Equations that utilized OCFA as a regressor to predict MicN under different MM resulted in good fits of the data as observed by the coefficient of determination (R2; 15N = 0.78; MNAB = 0.69). Microbial N flow estimated from OCFA was overpredicted (15N by 7.46%; MNAB by 4.30%) compared with observed values. The OCFA model presented a small slope bias when methodological validation was applied (15N = 0.96%; MNAB = 3.90%), ensuring reliability of the proposed alternative method. Based on the conditions of this experiment, OCFA may be a suitable alternative to other methods that quantify MicN under different dietary conditions.

Nutritional strategies that maximize microbial nitrogen supply to the small intestine may improve cattle performance. Nevertheless, in vivo quantification generally requires sensitive or expensive methods and often yields highly variable results. In the present work, we investigated the use of duodenal odd-chain fatty acids (OCFA) as an alternative method to predict microbial nitrogen flow (MicN) and calculated its efficiency on different energetic bases under different dietary nitrogen supplements. We utilized total OCFA flow (TOCFAf) to predict MicN by two well-established conventional methods: 1) 15N, considered the gold standard and 2) microbial nucleic acid bases. Models presented a positive relationship between TOCFDf and response variables, and under validation, both demonstrated low estimation bias. Under the conditions of this experiment, OCFA appeared to serve as an alternative marker to quantify ruminal MicN for beef cattle.

Trophic relationships between the crab Libinia ferreirae and its symbionts.

Symbioses are ubiquitous in the animal kingdom. However, in most cases, the role of each member is relatively fixed, and it is rare for the same species to exhibit different symbiotic behaviours throughout its ontogeny. Here, we use stable isotope analyses of food resources to identify the relationships between the spider crab Libinia ferreirae as a symbiont of its jellyfish host during juvenile life stages and as a host for sea anemone epibionts on its carapace as an adult. We ask the following questions: How do the food sources used by the crab change between its juvenile and adult phase? How does the symbiotic relationship change when the crab develops from a juvenile into an adult? We were particularly interested in the extent to which L. ferreirae juveniles feed on jellyfish hosts versus planktonic prey during the juvenile symbiont phase and how adults feed on their epibionts during the free-living phase. δ13C of L. ferreirae differed between juvenile (associated with the jellyfish) and adult stages (free-living), unsurprisingly suggesting that there is little isotopic niche overlap between these life phases. SIMMr models using δ13C and δ15N of the crab and its potential food sources indicated that the juvenile crab symbionts did not derive any significant nutrition from medusae and relied predominantly on zooplankton prey. Since juvenile crabs do not have structures to capture zooplankton for feeding, we suggest that they may be kleptoparasites, stealing zooplankton food from their host, though further work is needed to identify the form that such a symbiosis might take. The nutrition of free-living crabs was predominantly derived from benthic algae and shrimps rather than from epibionts. These epibionts appear to use similar food resources as the host, suggesting a symbiotic relationship more akin to mutualism. Thus, the crabs move from a symbiosis in which they may act as parasites to one where they act as hosts. Such flexible approaches to symbioses may be more common than currently described, particularly in species with different functional roles during individual life stages.

Effects of protein sources and inclusion levels on nitrogen metabolism and urea kinetics of Nellore feedlot steers fed concentrate-based diets.

Urea recycling occurs in all mammalian species and represents an important source of ruminal nitrogen (N) for ruminants fed protein-restricted diets. However, its importance for cattle fed adequate amounts of protein and energy remains unclear. Six Nellore feedlot steers fed concentrate-based diets were used in a 6 × 6 Latin square design with a 3 × 2 factorial arrangement of treatments to evaluate ruminal fermentation, urea kinetics, and N excretion. Treatments consisted of 3 protein sources (PS: soybean meal plus urea [SU], corn gluten meal [CGM], and dry distillers grains [DDG]) and 2 inclusion levels (PL; 11% and 14%). Steers were adapted to the diets for 14 d followed by 8 d of sample collection. Feed intake, fecal output, and urine production were measured from day 18 to day 22 of each period. Blood samples were collected every 6 h on day 18. [15N-15N]-urea was infused into the jugular vein for 82 h over day 19 to day 22, and measurement of 15N in background (day 18) and enriched feces and urine (day 21) were used to evaluate urea kinetics. To evaluate the incorporation of recycled urea N into microbial protein (MICP), ruminal and duodenal fluid were collected on day 22. Steers fed SU diets had lower (P < 0.05) nitrogen use efficiency (NUE), greater (P < 0.05) urea-N entry rate (UER), and tended (P < 0.10) to have greater gastrointestinal entry rate of urea-N (GER) compared with those fed CGM or DDG. In addition, steers fed SU had greater (P < 0.05) urea-N returned to ornithine cycle (ROC) compared with those fed CGM or DDG. Increasing PL tended (P < 0.10) to increase UER. The proportion of total microbial N from recycled urea-N was greater (P < 0.05) for steers fed CGM compared with those fed SU and also greater for steers fed diets with 11% CP than for those fed with 14% CP. Diets with 11% CP can be used for Nellore feedlot cattle fed concentrate-based diets without negatively affecting intake, digestibility, and ruminal fermentation. Moreover, diets containing rumen undegradable protein (RUP) feed sources (CGM or DDG) compared with diets with SU markedly increased NUE, while maintaining microbial protein (MICP) synthesis. Results from this study suggest that the equation adopted by NASEM (NASEM. 2016. Nutrient requirements of beef cattle. 8th revised ed. Washington, DC: The National Academies Press) was not accurate in estimating the urea-N used for anabolism (UUA) in Nellore feedlot cattle fed concentrate-based diets.

Sink strength of citrus rootstocks under water deficit.

Carbon allocation between source and sink organs determines plant growth and is influenced by environmental conditions. Under water deficit (WD), plant growth is inhibited before photosynthesis and shoot growth tends to be more sensitive than root growth. However, the modulation of the source-sink relationship by rootstocks remains unsolved in citrus trees under WD. Citrus plants grafted on Rangpur lime are drought tolerant, which may be related to a fine coordination of the source-sink relationship for maintaining root growth. Here, we followed 13C allocation and evaluated physiological responses and growth of Valencia orange trees grafted on three citrus rootstocks (Rangpur lime, Swingle citrumelo and Sunki mandarin) under WD. As compared with plants on Swingle and Sunki rootstocks, ones grafted on Rangpur lime showed higher stomatal sensitivity to the initial variation of water availability and less accumulation of non-structural carbohydrates in roots under WD. High 13C allocation found in Rangpur lime roots indicates this rootstock has high sink demand associated with high root growth under WD. Our data suggest that Rangpur lime rootstock used photoassimilates as sources of energy and carbon skeletons for growing under drought, which is likely related to increases in root respiration. Taken together, our data revealed that carbon supply by leaves and delivery to roots are critical for maintaining root growth and improving drought tolerance, with citrus rootstocks showing differential sink strength under WD.

Is breath testing without 13C-labelled external urea able to detect Helicobacter pylori infection?

Helicobacter pylori (H. pylori) infection is the main cause of gastric inflammation and peptic ulcer disease. Diagnosis and treatment are important to prevent these outcomes. The diagnosis of H. pylori infection can be performed by non-invasive methods, such as 13C-urea breath test (13C-UBT). As endogenous urea is normally released to body cavities, we sought to investigate the usefulness of UBT without 13C-labelled external urea to detect H. pylori infection. The analysis was performed in a series of adult patients just before upper gastrointestinal endoscopy and biopsy to investigate dyspeptic symptoms. Breath samples were analyzed using isotope ratio mass spectrometry (IRMS). The natural variation of 13C and 18O isotopic abundance in the breath samples was also investigated. The results of the isotopic analysis were compared with the findings of the histopathological evaluation of gastric biopsies, which is the gold standard to detect H. pylori infection. No differences between patients with or without H. pylori infection could be detected by the isotope analysis of breath tests without 13C-urea. Therefore, our results showed that UBT without 13C-urea, analyzed by IRMS, was not useful to detect H. pylori infection in the study population.

IRMS as a tool to obtain the carbon turnover (δ13 C) in organs of weaned piglets fed glutamic acid and nucleotides.

Early weaning of piglets causes stress characterized by a decrease in feed intake followed by a decline in growth rates; thus, a fast recovery represents an essential step for proper growth of these animals. Considering that IRMS is a potential tool for non-destructive sampling and the fact that it provides time-integrated estimate of assimilated and not just ingested nutrients turned possible its application to evaluate the effects of dietary nucleotides and glutamate on carbon turnover (δ13 C) in organs of weanling piglets. At day 0, three piglets were slaughtered (prior to diet switch), the remaining eighty-four piglets weaned at 21-day-old were randomly assigned in a complete block design with a 2 × 2 factorial arrangement of treatments (two Nu levels: 0 and 0.1% and two Glu levels: 0 and 1%), being three piglets per treatment slaughtered on trial days 3, 6, 9, 14, 21, 35 and 49. The samples were analysed by IRMS and adjusted to first-order equation by a non-linear regression analysis using NLIN of SAS, in order to establish exponential graphics. After that, the turnover data were submitted to analysis of variance using GLM of SAS. The turnover value (t95% ) verified for spleen was faster (p < 0.05) when glutamate was supplemented in diets. For pancreas and liver, the turnover rates were faster (p < 0.05) for the mixture of additives. However, for renal tissue, the turnover rate (t95% ) was greater (p < 0.05) for the free additive diet. The results obtained suggest that the mixture of additives was more efficient to develop the digestive tract at post-weaning phase, taking into account the functional importance of pancreas and liver for nutrients' digestion and processing.

Systematic Evaluation of Field Crop Performance Using Modern Phenotyping Tools and Techniques.

The genetic improvement of field crops through plant breeding and genetic modification is highly dependent on understanding, measuring, selecting, and manipulating phenotypes. Most phenotypes result from the complex interaction of a crop's genetics with the environment and management practices in which that crop is grown. Linking gene to phenotype in field environments to create superior crop varieties can therefore be challenging, particularly for genetically complex traits that are difficult to measure. This chapter is designed to help readers overcome these difficulties by describing tools and techniques used in successful crop improvement programs. It provides methodologies that can be broadly applied across numerous situations irrespective of field crop, environment, modest financial resources, or other factors. The chapter's focus is primarily on small- and large-scale, replicated, research plot-based screening trials since these trials are crucial, ubiquitous, and costly for both public- and private-sector crop improvement programs. To ease the understanding of the protocols discussed, this chapter's materials and methods section is composed of ten subsections, with each subsection covering a critical portion of the field crop phenotyping process: regulatory, environmental, and safety considerations; trait identification and prioritization; environment characterization; field site selection; experimental design; field design, preparation, and management; crop and soil measurements; environmental monitoring; in-field data recording; and data management and analysis.

Timing carbon turnover (δ13C) in weaned piglet's brain by IRMS.

Isotope-ratio mass spectrometry (IRMS) is a potential tool that provides time-integrated estimate of assimilated and not just ingested nutrients. This feature turned possible its application to evaluate the effects of dietary nucleotides and glutamate on carbon turnover (δ13C) in the brain of weanling piglets. Eighty-seven piglets weaned at 21-day-old were used, being three piglets slaughtered at day-0 (prior to diet-switch) and, the remaining 84 randomly assigned in a complete block design with a 2 x 2 factorial arrangement of treatments (two nucleotide levels: 0% and 0.1% and, two glutamate levels: 0% and 1%). On trial days 3, 6, 9, 14, 21, 35 and 49, three piglets per treatment were also slaughtered. The samples were analyzed by IRMS and adjusted to the first-order equation by a nonlinear regression analysis using NLIN procedure of SAS, in order to obtain the exponential graphics. The carbon turnover (t95%) verified for cerebral tissue was faster (P<0.05) for diet containing glutamate in comparison to other diets, supporting the fact that glutamate contributed to develop the piglets' brain, due to the fastest incorporation of 13C-atoms in this tissue at post-weaning phase, despite the energy deficit experienced by them.

Lateral Flow Assay for Interleukin 6: A Technological and Scientific Prospection of a 10-Year Survey.

BACKGROUND: Interleukin-6 (IL-6) is a multifunctional cytokine that plays a crucial role not only in the immune system but also in numerous biological processes. Elevated IL-6 levels have been observed in many types of cancer and inflammatory diseases. Among the techniques that have been used to quantify IL-6, a Lateral Flow Assay (LFA) is one of the most promising. OBJECTIVE: The objective of this study was to perform a technological and scientific exploration of the development of an LFA for IL-6. METHOD: The Instituto Nacional de Propriedade Industrial-INPI (Brazil), European Patent Office - Espacenet, and United States Patent and Trademark Office-USPTO were used for the technological prospection to consider all the patents regarding an LFA for IL-6 detection. For the scientific investigation, the following periodic databases were used: Web of Science, Science Direct, PubMed, and Scielo, and were monitored from 2007 to May 2017. RESULTS: We found no patents based on the searched keywords, and a limited number of scientific articles were found. Therefore, the development of an LFA sensor for the detection of IL-6 appears to be innovative with significant biotechnological importance, creating a technology transfer to promote economic and industrial growth. CONCLUSION: The development of lateral flow immunosensors for IL-6 is innovative, as we could not find patents describing such a biosensor. Scientific prospection reported two lateral flow immunosensors. However, the test for IL-6 cannot be completed without using some kind of equipment for detection, such as the one we propose in future developments.

Cry1A(b)16 toxin from Bacillus thuringiensis: Theoretical refinement of three-dimensional structure and prediction of peptides as molecular markers for detection of genetically modified organisms.

Transgenic maize produced by the insertion of the Cry transgene into its genome became the second most cultivated crop worldwide. Cry gene from Bacillus thuringiensis kurstaki expresses protein derivatives of crystalline endotoxins which confer insect resistance onto the maize crop. Mandatory labeling of processed food containing or made by genetically modified organisms is in force in many countries, so, it is very urgent to develop fast and practical methods for GMO identification, for example, biosensors. In the absence of an available empirical structure of Cry1A(b)16 protein, a theoretical model was effectively generated, in this work, by homology modeling and molecular dynamics simulations based on two available homologous protein structures. Molecular dynamics simulations were carried out to refine the selected model, and an analysis of its global structure was performed. The refined models of Cry1A(b)16 showed a standard fold and structural characteristics similar to those seen in Bacillus thuringiensis Cry1A(a) insecticidal toxin and Bacillus thuringiensis serovar kurstaki Cry1A(c) toxin. After in silico analysis of Cry1A(b)16, two immunoreactive candidate peptides were selected and specific polyclonal antibodies were produced resulting in antibody-peptide interaction. Biosensing devices are expected to be developed for detection of the Cry1A(b) protein as a marker of transgenic maize in food. Proteins 2017; 85:1248-1257. © 2017 Wiley Periodicals, Inc.

The skin secretion of the amphibian Phyllomedusa nordestina: a source of antimicrobial and antiprotozoal peptides.

Antimicrobial peptides (AMPs) from the dermaseptin and phylloseptin families were isolated from the skin secretion of Phyllomedusa nordestina, a recently described amphibian species from Northeastern Brazil. One dermaseptin and three phylloseptins were chosen for solid phase peptide synthesis. The antiprotozoal and antimicrobial activities of the synthetic peptides were determined, as well as their cytotoxicity in mouse peritoneal cells. AMPs are being considered as frameworks for the development of novel drugs inspired by their mechanism of action.

Leishmanicidal activity and immobilization of dermaseptin 01 antimicrobial peptides in ultrathin films for nanomedicine applications.

Antimicrobial peptides (AMPs) are essential for the innate immune system of eukaryotes, imparting protection against pathogens and their proliferation in host organisms. The recent interest in AMPs as active materials in bionanostructures is due to the properties shown by these biological molecules, such as the presence of an alpha-helix structure and distribution of positive charges along the chain. In this study the antimicrobial peptide dermaseptin 01 (DS 01), from the skin secretion of Phyllomedusa hypochondrialis frogs was immobilized in nanostructured layered films in conjunction with nickel tetrasulfonated phthalocyanines. The leishmanicidal activity of DS 01 was confirmed using kinetic essays, in which DS 01 promoted death of all metacyclic promastigote cells in 45 minutes. Surprisingly, the immobilized DS 01 molecules displayed electroactivity, as revealed by electrochemical experiments, in which an oxidation peak at about 0.61 V was observed for a DS 01 monolayer deposited on top of a conductive electrode. Such electroactivity was used to investigate the sensing abilities of the nanostructured films toward Leishmania. We observed an increase in the oxidation current as a function of number of Leishmania cells in the electrolytic solution at concentrations down to 10(3) cells/mL. The latter is indicative that the use of AMPs immobilized in electroactive nanostructured films may be of interest for applications in the pharmaceutical industry and diagnosis. FROM THE CLINICAL EDITOR: The recent interest in Antimicrobial peptides (AMPs) as active materials in bionanostructures is due to the properties shown by these biological molecules. Leishmanicidal activity of a particular AMP is demonstrated in this paper.