Understanding the effect of sex on energy requirements of hair sheep

Differences and/or similarities in the influence of sex class for hair sheep requirements remain inconclusive. Knowledge of energy requirements allows well-formulated diets to be provided which is crucial for improving animal production. We aimed to determine the effect of sex class on the net energy requirements of growing hair sheep in a multi-study approach. We used a data set composed of individual measurements of 382 hair sheep (299 non-castrated and 83 castrated males) from 11 studies that used the methodology of comparative slaughter. Net energy requirements for maintenance (NEm) were obtained by the regression between heat production and metabolizable energy intake. The metabolizable energy requirements for maintenance (MEm) were calculated by the iterative method, and the efficiency of use of metabolizable energy for maintenance (km) was obtained by NEm divided by MEm. The net energy requirements for gain (NEg) were estimated from retained energy (RE) against empty BW gain (EBWG). The efficiency of energy use for weight gain (kg) was obtained from the relationship between RE and the energy metabolizable intake for gain, removing the intercept. There was an effect of sex on NEg and two equations were generated: NEg (MJ/day) = 1.040 (±0.04055) × EBW0.75 × EBWG0.8767(±0.03293) and NEg (MJ/day) = 1.040 (±0.04055) × EBW0.75 × EBWG0.8300(±0.03468) (R2 = 0.86; MSE = 0.0037; AIC = -468.0) for non-castrated and castrated males, respectively. Sex class did not affect kg (P > 0.05) and one kg was generated (0.29). Sex did not affect kprotein (P = 0.14) and kfat (P = 0.32), assuming an average deposition efficiency of 0.27 for protein and 0.78 for fat. The NEm and MEm did not differ (P > 0.05) between sex classes, with a value of 0.272 and 0.427 MJ/kg0.75 EBW per day, respectively. The km observed was 0.64. In conclusion, non-castrated and castrated male hair sheep have similar maintenance energy requirements although energy requirements for gain differed among them. The Committees overestimate the gain and maintenance requirements for hair sheep. Therefore, the equations generated in this study are recommended.

Accurate selected ion flow tube mass spectrometry quantification of ethylene oxide contamination in the presence of acetaldehyde

In September 2020, traces of ethylene oxide (a toxic substance used as a pesticide in developing countries but banned for use on food items within the European Union) were found in foodstuffs containing ingredients derived from imported sesame seed products. Vast numbers of foodstuffs were recalled across Europe due to this contamination, leading to expensive market losses and extensive trace exposure of ethylene oxide to consumers. Therefore, a rapid analysis method is needed to ensure food safety by high-throughput screening for ethylene oxide contamination. Selected ion flow tube mass spectrometry (SIFT-MS) is a suitable method for rapid quantification of trace amounts of vapours in the headspace of food samples. It turns out, however, that the presence of acetaldehyde complicates SIFT-MS analyses of its isomer ethylene oxide. It was proposed that a combination of the H3O+ and NO+ reagent ions can be used to analyse ethylene oxide in the presence of acetaldehyde. This method is, however, not robust because of the product ion overlaps and potential interferences from other matrix species. Thus, we studied the kinetics of the reactions of the H3O+, NO+, OH- and O-˙ ions with these two compounds and obtained their rate coefficients and product ion branching ratios. Interpretation of these experimental data revealed that the OH- anions are the most suitable SIFT-MS reagents because the product ions of their reactions with acetaldehyde (CH2CHO- at m/z 43) and ethylene oxide (C2H3O2- at m/z 59) do not overlap.

Thermophilic Dehalococcoidia with unusual traits shed light on an unexpected past

Although the phylum Chloroflexota is ubiquitous, its biology and evolution are poorly understood due to limited cultivability. Here, we isolated two motile, thermophilic bacteria from hot spring sediments belonging to the genus Tepidiforma and class Dehalococcoidia within the phylum Chloroflexota. A combination of cryo-electron tomography, exometabolomics, and cultivation experiments using stable isotopes of carbon revealed three unusual traits: flagellar motility, a peptidoglycan-containing cell envelope, and heterotrophic activity on aromatics and plant-associated compounds. Outside of this genus, flagellar motility has not been observed in Chloroflexota, and peptidoglycan-containing cell envelopes have not been described in Dehalococcoidia. Although these traits are unusual among cultivated Chloroflexota and Dehalococcoidia, ancestral character state reconstructions showed flagellar motility and peptidoglycan-containing cell envelopes were ancestral within the Dehalococcoidia, and subsequently lost prior to a major adaptive radiation of Dehalococcoidia into marine environments. However, despite the predominantly vertical evolutionary histories of flagellar motility and peptidoglycan biosynthesis, the evolution of enzymes for degradation of aromatics and plant-associated compounds was predominantly horizontal and complex. Together, the presence of these unusual traits in Dehalococcoidia and their evolutionary histories raise new questions about the timing and selective forces driving their successful niche expansion into global oceans.

Protist impacts on marine cyanovirocell metabolism

The fate of oceanic carbon and nutrients depends on interactions between viruses, prokaryotes, and unicellular eukaryotes (protists) in a highly interconnected planktonic food web. To date, few controlled mechanistic studies of these interactions exist, and where they do, they are largely pairwise, focusing either on viral infection (i.e., virocells) or protist predation. Here we studied population-level responses of Synechococcus cyanobacterial virocells (i.e., cyanovirocells) to the protist Oxyrrhis marina using transcriptomics, endo- and exo-metabolomics, photosynthetic efficiency measurements, and microscopy. Protist presence had no measurable impact on Synechococcus transcripts or endometabolites. The cyanovirocells alone had a smaller intracellular transcriptional and metabolic response than cyanovirocells co-cultured with protists, displaying known patterns of virus-mediated metabolic reprogramming while releasing diverse exometabolites during infection. When protists were added, several exometabolites disappeared, suggesting microbial consumption. In addition, the intracellular cyanovirocell impact was largest, with 4.5- and 10-fold more host transcripts and endometabolites, respectively, responding to protists, especially those involved in resource and energy production. Physiologically, photosynthetic efficiency also increased, and together with the transcriptomics and metabolomics findings suggest that cyanovirocell metabolic demand is highest when protists are present. These data illustrate cyanovirocell responses to protist presence that are not yet considered when linking microbial physiology to global-scale biogeochemical processes.

Genomics, Exometabolomics, and Metabolic Probing Reveal Conserved Proteolytic Metabolism of Thermoflexus hugenholtzii and Three Candidate Species From China and Japan

Thermoflexus hugenholtzii JAD2^T, the only cultured representative of the Chloroflexota order Thermoflexales, is abundant in Great Boiling Spring (GBS), NV, United States, and close relatives inhabit geothermal systems globally. However, no defined medium exists for T. hugenholtzii JAD2^T and no single carbon source is known to support its growth, leaving key knowledge gaps in its metabolism and nutritional needs. Here, we report comparative genomic analysis of the draft genome of T. hugenholtzii JAD2^T and eight closely related metagenome-assembled genomes (MAGs) from geothermal sites in China, Japan, and the United States, representing “Candidatus Thermoflexus japonica,” “Candidatus Thermoflexus tengchongensis,” and “Candidatus Thermoflexus sinensis.” Genomics was integrated with targeted exometabolomics and ¹³C metabolic probing of T. hugenholtzii. The Thermoflexus genomes each code for complete central carbon metabolic pathways and an unusually high abundance and diversity of peptidases, particularly Metallo- and Serine peptidase families, along with ABC transporters for peptides and some amino acids. The T. hugenholtzii JAD2^T exometabolome provided evidence of extracellular proteolytic activity based on the accumulation of free amino acids. However, several neutral and polar amino acids appear not to be utilized, based on their accumulation in the medium and the lack of annotated transporters. Adenine and adenosine were scavenged, and thymine and nicotinic acid were released, suggesting interdependency with other organisms in situ. Metabolic probing of T. hugenholtzii JAD2^T using ¹³C-labeled compounds provided evidence of oxidation of glucose, pyruvate, cysteine, and citrate, and functioning glycolytic, tricarboxylic acid (TCA), and oxidative pentose-phosphate pathways (PPPs). However, differential use of position-specific ¹³C-labeled compounds showed that glycolysis and the TCA cycle were uncoupled. Thus, despite the high abundance of Thermoflexus in sediments of some geothermal systems, they appear to be highly focused on chemoorganotrophy, particularly protein degradation, and may interact extensively with other microorganisms in situ.

Weight adjustment equation for hair sheep raised in warm conditions

To estimate the nutritional requirements of hair sheep, knowledge about the animal's weight and its relationships with growth performances is essential. A study was carried with the objective to establish the relationships between BW, fasting BW (FBW), empty BW (EBW), average daily gain (ADG) and empty BW gain (EBWG) for hair sheep in growing and finishing phases in Brazilian conditions. Databases were obtained from 32 studies, for a total of 1145 observations; there were 3 sex classes (non-castrated male, castrated male and female) and 2 feeding systems (pasture and feedlot). The most representative breeds in the database were Santa Ines (n = 473), Morada Nova (n = 70) and Brazilian Somali (n = 47). The other animals in the database were crossbreeds (n = 555). The FBW (kg), EBW and EBWG (kg/day) were estimated according to linear regression. A random coefficient model was adopted, considering the study as a random effect and including the possibility of covariance between the slope and the intercept. The coefficients obtained from the linear regression of the FBW against the BW, EBW against the FBW and EBWG against the ADG did not differ between sex class (P > 0.05) and genotype (P > 0.05). The equations generated to estimate FBW from the BW, EBW from the FBW and EBWG from the ADG are as follows: FBW = -0.5470 (±0.2025) + 0.9313(±0.019) × BW, EBW = -1.4944 (±0.3639) + 0.8816 (±0.018) × FBW and EBWG = 0.906 (±0.019) × ADG, respectively. The low mean squared error values found in the cross-validation confirmed the reliability of these equations. Considering a sheep with a BW of 30 kg and a 100 g ADG, the estimated FBW, EBW and EBWG calculated using the generated equations are 27, 22.65 and 0.090 kg, respectively. In conclusion, the generated equations can be used in growing hair sheep. The validation procedure applied to the generated equations showed that its use for hair sheep seems to be appropriate.

Hepatic and cardiac and iron overload detected by T2* magnetic resonance (MRI) in patients with myelodisplastic syndrome: A cross-sectional study

INTRODUCTION

Transfusion-dependent anemia and iron overload are associatedwith reduced survival in myelodysplastic syndrome (MDS). This cross-sectional study aimed to evaluate the prevalence of hepatic and cardiac overload in patients with MDS as measured by T2* magnetic resonance imaging (MRI), and its correlation with survival.

METHODS

MDS or chronic myelomonocytic leukemia patients had iron overload evaluated by T2* MRI. HIO was considered when hepatic iron concentration ≥ 2 g/mg. Cardiac iron overload was considered with a T2*-value < 20 ms.

RESULTS

Among 71 patients analyzed, median hepatic iron concentration was 3.9 g/mg (range 0.9-16 g/mg), and 68%of patients had hepatic iron overload. Patients with hepatic iron overload had higher mean ferritin levels (1182 ng/mL versus 185 ng/mL, p < 0.0001), transferrin saturation (76% versus 34%, p < 0.0001) and lower survival rates. Median cardiac T2*value was 42 ms (range 19.7-70.1 ms), and only one patienthad a T2* value indicative of cardiac iron overload.

CONCLUSIONS

Hepatic iron overload is found in two thirds of patients, even in cases without laboratory signs of iron overload. Hepatic iron overload by T2* MRI is associated with a decreased risk of survival in patients with MDS.

Lighting programs for male and female meat quails (Coturnix coturnix) raised in equatorial region

The aim of the present study was to evaluate the effect of lighting programs for male and female meat quails raised in an equatorial region on performance and carcass traits. A total of 1,500 sexed quails (Coturnix coturnix) was distributed in a completely randomized design in a 2 × 3 factorial arrangement, with 2 sexes (male and female) and 3 lighting programs (natural, intermittent, and continuous) with 5 replicates of 50 birds. The lighting programs were applied in the period from 7 to 49 d of age, being natural (12 h and 30 min of natural light and 11 h and 30 min of dark), intermittent (12 h and 30 min of natural light and 5 h and 30 min of artificial light, alternating lighting periods with one h and 06 min and periods of darkness with one h and 12 min), and continuous (23 h of natural + artificial light and one h of dark). Regardless of lighting program, female quails were heavier than males, and birds subjected to natural light weighed less than those exposed to continuous and intermittent lighting programs. Quails exposed to intermittent and continuous light presented higher weight gain and feed intake, and worse feed conversion ratio compared to birds under a natural light regimen. It is concluded that in an equatorial region, it is possible to use a lighting program with only natural light for raising male and female meat quails from 7 to 49 d of age.

Relationship between the expression of versican and EGFR, HER-2, HER-3 and CD44 in matrix-producing tumours in the canine mammary gland

Versican is an extracellular matrix proteoglycan that has been identified as a modulator of adhesion loss, cell motility, and tumour progression. This motility results from the interaction between versican and cell surface receptors. Studies have also demonstrated the relationship between this molecule and invasion in canine mammary tumours. Given the evidence for the participation of proteoglycans in tumour progression, this study aimed to assess versican expression and its association with cell surface receptors; human epidermal growth factor receptors 1, 2, and 3 (EGFR, HER-2, and HER-3) and CD44 through an immunohistochemical analysis of benign mixed tumours (BMTs), carcinomas in mixed tumours (CMTs), and carcinosarcomas (CSs) of the canine mammary gland. Malignant tumours were divided into low and high groups with respect to versican stromal expression. The results indicated that the BMTs showed weak stromal versican expression and correlations between the expression of stromal versican and EGFR in the epithelial membrane in benign areas (p=0.013, r=0.571). A higher stromal versican expression was observed adjacent to invasive epithelial areas compared with in situ areas in CMTs and CSs, suggesting a direct relationship between versican expression and invasiveness. Furthermore, the CSs exhibited a higher expression of HER-2, cytoplasmic HER-3, and CD44 in epithelial invasive cells in cases of higher stromal versican expression. Therefore, the cell surface receptors (HER-2, HER-3, and CD44) are more evident in CSs that overexpress versican in stroma adjacent to the invasive areas. These findings suggest that the association between these molecules may be directly related to the biological behaviour and invasiveness of these canine mammary tumours.

Genetic evaluation of milk yield in Alpine goats for the first four lactations using random regression models

Random regression models have been used in evaluating test-day milk yield, providing accurate estimates of genetic values in animals. However, herd evaluation with only information from the first lactation may not be the best option from an economic perspective. Other factors should be taken into account, particularly other lactations. Our objective in this study was to analyze the genetic divergence between the first four lactations of Alpine goats. The RENPED software was used to perform descriptive statistics, check for errors in pedigree, recode the data, and for Pearson's and Spearman's correlations. The WOMBAT software was used to estimate the variance components and predict the breeding values. The CALC software was adopted to calculate the percentage of coincidence between the ranking of the animals and the animals kept in common at each lactation evaluation. The results show that selection using only the first lactation in small herds with a low degree of technology can be employed as a palliative measure, in view of the difficulty in evaluating all lactations. However, the selection of breeding goats and the production of catalogues should not be based only on the first lactation, because the results demonstrate inversions in the classification of the best breeders when other lactations are analyzed.

Benchtop isolation and characterization of functional exosomes by sequential filtration

Early and minimally invasive detection of malignant events or other pathologies is of utmost importance in the pursuit of improved patient care and outcomes. Recent evidence indicates that exosomes and extracellular vesicles in serum and body fluids can contain nucleic acid, protein, and other biomarkers. Accordingly, there is great interest in applying these clinically as prognostic, predictive, pharmacodynamic, and early detection indicators. Nevertheless, existing exosome isolation methods can be time-consuming, require specialized equipment, and/or present other inefficiencies regarding purity, reproducibility and assay cost. We have developed a straightforward, three-step protocol for exosome isolation of cell culture supernatants or large volumes of biofluid based on sequential steps of dead-end pre-filtration, tangential flow filtration (TFF), and low-pressure track-etched membrane filtration that we introduce here. Our approach yields exosome preparations of high purity and defined size distribution and facilitates depletion of free protein and other low-molecular-weight species, extracellular vesicles larger than 100nm, and cell debris. Samples of exosomes prepared using the approach were verified morphologically by nanoparticle tracking analysis and electron microscopy, and mass spectrometry analyses confirmed the presence of previously reported exosome-associated proteins. In addition to being easy-to-implement, sequential filtration yields exosomes of high purity and, importantly, functional integrity as a result of the relatively low-magnitude manipulation forces employed during isolation. This answers an unmet need for preparation of minimally manipulated exosomes for investigations into exosome function and basic biology. Further, the strategy is amenable to translation for clinical exosome isolations because of its speed, automatability, scalability, and specificity for isolating exosomes from complex biological samples.

Cardiac autonomic responses at onset of exercise: effects of aerobic fitness

Analyzes of cardiac autonomic responses at the initial transient of exercise have been used for the investigation of the cardiovascular health. We evaluated the influence of aerobic fitness on HR and HRV responses at the onset of exercise. 25 male subjects (22.3±2.4 years) were divided into 2 groups: 'low aerobic fitness' (36.2±2.6ml.kg(-1).min(-1); n=10) and 'high aerobic fitness' (46.4±5.0ml.kg(-1).min(-1); n=15). The experimental session consisted of assessing the beat-to-beat HR at rest and during submaximal exercise. The autonomic responses at the onset of exercise were calculated by fitting the HR and HRV (rMSSD-index) curves during the initial 300s of exercise into a first-order exponential equation. The time constant of HR and of the rMSSD index (τonHR and τonrMSSD) were calculated for analysis. We observed lower values of τonrMSSD in the high aerobic fitness group compared to the low aerobic fitness group (26.8±5s vs. 38.0±18s, respectively; p=0.02). The τonHR (42.0±15 vs. 49.3±26s, p=0.38) for the groups showed no difference. Aerobic fitness partially influenced the autonomic responses during exercise, since individuals with higher fitness showed faster decreases in beat-to-beat HRV at the onset of exercise.

Targeted metabolomic analysis of amino acid response to L-asparaginase in adherent cells

L-asparaginase (L-ASP) is a therapeutic enzyme used clinically for the treatment of childhood acute lymphoblastic leukemia. L-ASP's anticancer activity is believed to be associated primarily with depletion of asparagine, but secondary glutaminase activity has also been implicated in its anticancer mechanism of action. To investigate the effects of L-ASP on amino acid metabolism, we have developed an LC-MS/MS metabolomics platform for high-throughput quantitation of 29 metabolites, including all 20 proteinogenic amino acids, 6 metabolically related amino acid derivatives (ornithine, citrulline, sarcosine, taurine, hypotaurine, and cystine), and 3 polyamines (putrescince, spermidine, and spermine) in adherent cultured cells. When we examined the response of OVCAR-8 ovarian cancer cells in culture to L-ASP, asparagine was depleted from the medium within seconds. Interestingly, intracellular asparagine was also depleted rapidly, and the mechanism was suggested to involve rapid export of intracellular asparagine followed by rapid conversion to aspartic acid by L-ASP. We also found that L-ASP-induced cell death was more closely associated with glutamine concentration than with asparagine concentration. Time-course analysis revealed the dynamics of amino acid metabolism after feeding cells with fresh medium. Overall, this study provides new insight into L-ASP's mechanism of action, and the optimized analytical method can be extended, with only slight modification, to other metabolically active amino acids, related compounds, and a range of cultured cell types.

Influence of animals obtained using embryo transfer on the genetic evaluation of growth in Simmental beef cattle with random regression models

Weight records of Simmental beef cattle were used in a genetic evaluation of growth with and without embryo transfer (ET). A random regression model in which ET individuals were excluded (RRM1) contained 29,510 records from 10,659 animals, while another model that did not exclude these animals (RRM2) contained 62,895 records from 23,160 animals. The fixed and random regressions were represented by continuous functions, and a model with an order of three for the fixed curve and random effects was used to consider the homogeneity of residual variance. In general, the (co)variance components were similar in both models, except the maternal permanent environment and residual components. The direct heritability in RRM1 and RRM2 showed the same behavior with oscillations along the growth curve and were slightly higher in RRM1. Generally, the estimated correlations were the same and smaller as the ages distanced themselves. The inclusion of animals from ET in genetic evaluations can be done using random regression models; the inclusion of these animals would provide potential accuracy gains and greater genetic gains per unit time because of the reduction in the generation interval from the use of this reproductive technique.

Measurement of DNA concentration as a normalization strategy for metabolomic data from adherent cell lines

Metabolomics is a rapidly advancing field, and much of our understanding of the subject has come from research on cell lines. However, the results and interpretation of such studies depend on appropriate normalization of the data; ineffective or poorly chosen normalization methods can lead to frankly erroneous conclusions. That is a recurrent challenge because robust, reliable methods for normalization of data from cells have not been established. In this study, we have compared several methods for normalization of metabolomic data from cell extracts. Total protein concentration, cell count, and DNA concentration exhibited strong linear correlations with seeded cell number, but DNA concentration was found to be the most generally useful method for the following reasons: (1) DNA concentration showed the greatest consistency across a range of cell numbers; (2) DNA concentration was the closest to proportional with cell number; (3) DNA samples could be collected from the same dish as the metabolites; and (4) cell lines that grew in clumps were difficult to count accurately. We therefore conclude that DNA concentration is a widely applicable method for normalizing metabolomic data from adherent cell lines.

24-h cardiac autonomic profile after exercise in sedentary subjects

Most studies regarding the impact of exercise intensity on cardiac autonomic regulation were conducted with athletes and used exercise intensities exceeding those recommended by position stands. We evaluated the influence of exercise intensity in a typical ACSM-aerobic session on 24-h cardiac autonomic modulation in sedentary subjects. Ten healthy sedentary subjects participated in the 3-day study. On 2 days, subjects performed a moderate- or high-intensity aerobic exercise session (MI, HI). The post-exercise protocol consisted of a continuous electrocardiographic recording for 1 h at the laboratory plus 23 h under ambulatory conditions. On the third day 24-h electrocardiographic recording was done without prior exercise (NPE). Heart rate (HR) and frequency-domain parameters (LF, HF) of heart rate variability were evaluated during the entire recovery period. Higher values of HR and lower values of HF and LF were observed throughout the first hour after the HI compared with the MI session. This difference was not observed after in ambulatory awake condition, but reappeared during sleep, when HF values after HI were lower compared with the NPE and MI (p<0.05). Even within the submaximal intensity-range of a typical exercise session, the intensity of exercise influences the post-exercise cardiac autonomic modulation in sedentary subjects.

Evaluation of alternative schemes for recording body weights in meat-type quails by using random regression

Data from 8759 meat-type quails from the UFV1 strain and 9128 from the UFV2 strain were used to assess the possibility of reducing the number of body weight records in genetic evaluations. The evaluated animals were weighed weekly since hatching to the 6th week of life, with up to 7 records of body weight for each bird. The data were evaluated by random regression models, with 9 alternative schemes of data recording, which included 4 records for each scheme and their covariance functions for additive and permanent environmental effects of order 3, fitting 4 intervals for residual variance, and a complete scheme, with 7 records, order of fit 6 for additive and permanent environmental effects and 7 intervals for residual variance. Estimates of heritability for body weight at the 6th week varied from 0.45 to 0.53 for the UFV1 strain and from 0.28 to 0.54 for UFV2 strain. The schemes that had more records in points at the final extreme of the age range showed better estimates, which was likely due to certain properties of polynomial regression that led to biased results in the final extreme of the age range when data are unbalanced. The reduction of the number of body weight records taken during the growth phase is feasible, with little change to breeding value estimates, when 4 body weight records are used in random regression models.

The membrane-binding domain of an amphitropic enzyme suppresses catalysis by contact with an amphipathic helix flanking its active site

CTP:phosphocholine cytidylyltransferase (CCT), the regulatory enzyme in the synthesis of phosphatidylcholine, is activated by binding membranes using a lipid-induced amphipathic helix (domain M). Domain M functions to silence catalysis when CCT is not membrane engaged. The silencing mechanism is unknown. We used photo-cross-linking and mass spectrometry to identify contacts between domain M and other CCT domains in its soluble form. Each of four sites in domain M forged cross-links to the same set of peptides that flank the active site and overlap at helix αE at the base of the active site. These cross-links were broken in the presence of activating lipid vesicles. Mutagenesis of domain M revealed that multiple hydrophobic residues within a putative auto-inhibitory (AI) motif contribute to the contact with helix αE and silencing. Helix αE was confirmed as the docking site for domain M by deuterium exchange analysis. We compared the dynamics and fold stability of CCT domains by site-directed fluorescence anisotropy and urea denaturation. The results suggest a bipartite structure for domain M: a disordered N-terminal portion and an ordered C-terminal AI motif with an unfolding transition identical with that of helix αE. Reduction in hydrophobicity of the AI motif decreased its order and fold stability, as did deletion of the catalytic domain. These results support a model in which catalytic silencing is mediated by the docking of an amphipathic AI motif onto the amphipathic helices αE. An unstructured leash linking αE with the AI motif may facilitate both the silencing contact and its membrane-triggered disruption.

Reducing size-dispersion in one-pot aqueous synthesis of maghemite nanoparticles

Nanosized maghemite-like particles with reduced size-distribution were obtained using a one-pot synthesis route in aqueous medium. Forced hydrolysis of iron ions in ammoniac solution led to the formation of magnetite nanoparticles that were oxidized to maghemite in a hydrothermal digestion step that reduced the polydispersity of nanograins. The prepared nanoparticles were characterized by chemical analysis, X-ray diffractometry, magnetization, Raman spectroscopy and transmission electron microscopy measurements. Data showed that 14 nm-sized particles with polydispersity of about 0.14 were produced and, differently from other procedures, neither additional steps nor toxic reagents were needed to reduce size-dispersion or to oxidize magnetite to maghemite. These facts per se turn such nanodevice into a good potential choice for biomedical applications.

Assembly of Ebola virus matrix protein VP40 is regulated by latch-like properties of N and C terminal tails

The matrix protein VP40 coordinates numerous functions in the viral life cycle of the Ebola virus. These range from the regulation of viral transcription to morphogenesis, packaging and budding of mature virions. Similar to the matrix proteins of other nonsegmented, negative-strand RNA viruses, VP40 proceeds through intermediate states of assembly (e.g. octamers) but it remains unclear how these intermediates are coordinated with the various stages of the life cycle. In this study, we investigate the molecular basis of synchronization as governed by VP40. Hydrogen/deuterium exchange mass spectrometry was used to follow induced structural and conformational changes in VP40. Together with computational modeling, we demonstrate that both extreme N and C terminal tail regions stabilize the monomeric state through a direct association. The tails appear to function as a latch, released upon a specific molecular trigger such as RNA ligation. We propose that triggered release of the tails permits the coordination of late-stage events in the viral life cycle, at the inner membrane of the host cell. Specifically, N-tail release exposes the L-domain motifs PTAP/PPEY to the transport and budding complexes, whereas triggered C-tail release could improve association with the site of budding.

Conserved interaction between transferrin and transferrin-binding proteins from porcine pathogens

Gram-negative porcine pathogens from the Pasteurellaceae family possess a surface receptor complex capable of acquiring iron from porcine transferrin (pTf). This receptor consists of transferrin-binding protein A (TbpA), a transmembrane iron transporter, and TbpB, a surface-exposed lipoprotein. Questions remain as to how the receptor complex engages pTf in such a way that iron is positioned for release, and whether divergent strains present distinct recognition sites on Tf. In this study, the TbpB-pTf interface was mapped using a combination of mass shift analysis and molecular docking simulations, localizing binding uniquely to the pTf C lobe for multiple divergent strains of Actinobacillus plueropneumoniae and suis. The interface was further characterized and validated with site-directed mutagenesis. Although targeting a common lobe, variants differ in preference for the two sublobes comprising the iron coordination site. Sublobes C1 and C2 participate in high affinity binding, but sublobe C1 contributes in a minor fashion to the overall affinity. Further, the TbpB-pTf complex does not release iron independent of other mediators, based on competitive iron binding studies. Together, our findings support a model whereby TbpB efficiently captures and presents iron-loaded pTf to other elements of the uptake pathway, even under low iron conditions.

Structural variations within the transferrin binding site on transferrin-binding protein B, TbpB

Pathogenic bacteria acquire the essential element iron through specialized uptake pathways that are necessary in the iron-limiting environments of the host. Members of the Gram-negative Neisseriaceae and Pasteurellaceae families have adapted to acquire iron from the host iron binding glycoprotein, transferrin (Tf), through a receptor complex comprised of transferring-binding protein (Tbp) A and B. Because of the critical role they play in the host, these surface-exposed proteins are invariably present in clinical isolates and thus are considered prime vaccine targets. The specific interactions between TbpB and Tf are essential and ultimately might be exploited to create a broad-spectrum vaccine. In this study, we report the structure of TbpBs from two porcine pathogens, Actinobacillus pleuropneumoniae and suis. Paradoxically, despite a common Tf target, these swine related TbpBs show substantial sequence variation in their Tf-binding site. The TbpB structures, supported by docking simulations, surface plasmon resonance and hydrogen/deuterium exchange experiments with wild-type and mutant TbpBs, explain why there are structurally conserved elements within TbpB homologs despite major sequence variation that are required for binding Tf.

Identification of E. dysenterica laxative peptide: a novel strategy in the treatment of chronic constipation and irritable bowel syndrome

Plants have contributed over the years to the discovery of various pharmacological products. Amongst the enormous diversity of herbs with remarkable medicinal use and further pharmacological potential, here in this report we evaluated pulp extracts from Eugenia dysenterica fruits and further identified the active principle involved in such laxative activity in rats. For protein isolation, fruits were macerated with an extraction solution following precipitation with (NH(4))(2)SO(4) (100%). After dialysis, the peptide was applied onto a reversed-phase semi-preparative HPLC column, and the major fraction was eluted with 26% and 66% acetonitrile. The evaluation of molecular masses by MALDI-TOF and Tris/Tricine SDS-PAGE of HPLC fractions showed the presence of a major peptide with approximately 7 kDa. The N-terminal amino acid peptide sequence was determined and showed no similarity to other proteins deposited in the Data Bank. Peptide from E. dysenterica was able to enhance rats' intestinal motility by approximately 20.8%, probably being responsible for laxative activity. Moreover, these proteins were non-toxic to mammals, as observed in histopathology and hemolytic analyses. In conclusion, results here reported indicate that, in the near future, proteins synthesized by E. dysenterica fruits could be utilized in the development of novel biotechnological pharmaceutics with laxative properties for use in chronic constipation and irritable bowel syndrome treatment.

Influence of cereal bran supplement on cadmium effects in growing rats

Strategies to diminish cadmium (Cd) absorption are highly desirable especially where Cd exposure due to environmental contamination is still inevitable. Cd toxicity may be influenced by dietary components, such as fiber and minerals. Multimixtures are low-cost cereal bran supplements used in Brazil and in other countries to counteract malnutrition in low-income populations. This study was aimed at evaluating whether multimixture would reduce Cd effects in young rats. Animals received a diet with or without the multimixture plus 0, 5, or 25 mg Cd/kg (control, Cd-5, and Cd-25 groups) during 30 days. The Cd-5 groups were similar to control groups in all parameters analyzed, except in the higher renal Cd concentration. However, the Cd-25 groups had lower biological growth parameters and renal delta-aminolevulinate dehydratase activity, besides higher renal Cd concentration and plasma alanine aminotransferase activity compared to the controls. The multimixture did not prevent Cd effects in the Cd-25 group, but caused a small reduction in renal Cd concentration in the Cd-5 group. Although this multimixture was ineffective to prevent Cd effects at the higher concentration, it seemed to reduce Cd accumulation at the lower Cd dietary concentration, which is similar to levels of human exposure in some polluted areas.

Comparison of fatty acid composition in nine organs of the sympatric Antarctic teleost fish species Notothenia coriiceps and Notothenia rossii (Perciformes: Nototheniidae)

Fatty acid (FA) composition of nine organs from two closely related Antarctic fish species, Notothenia coriiceps and Notothenia rossii, was determined through gas chromatography with flame ionization detection. A data set for each species was obtained using major FA profiles from specimens caught in the sea waters of Admiralty Bay during the summer season. The FA profiles for both species are overall similar, but organ peculiarities have been found, which could reflect metabolic specificities and feeding habits between species. With the exception of liver, the most abundant FA in organs was the n-3 polyunsaturated FA. The total n-6 polyunsaturated FAs were minor components in all evaluated organs. Palmitic acid was identified as the major saturated FA, whereas oleic acid was the most represented of the monounsaturated FA in almost all assessed organs of both species. The n-3/n-6 ratios of all organs were higher than 3.5. Differences in individual FA and FA metabolic profiles of some organs observed between N. coriiceps and N. rossii suggest specific requirements in the mobilization, transport, incorporation, and/or catabolism of lipids that were reinforced by differences on some FA ratios expressing the activity coefficient of enzymes implicated on the FA pathway flux.

A retrospective comparison of cyclophosphamide plus antithymocyte globulin with cyclophosphamide plus busulfan as the conditioning regimen for severe aplastic anemia

Allogeneic hematopoietic stem cell transplantation (AHSCT) is the treatment of choice for young patients with severe aplastic anemia (SAA). The association of antithymocyte globulin (ATG) and cyclophosphamide (CY) is the most frequently used conditioning regimen for this disease. We performed this retrospective study in order to compare the outcomes of HLA-matched sibling donor AHSCT in 41 patients with SAA receiving cyclophosphamide plus ATG (ATG-CY, N = 17) or cyclophosphamide plus busulfan (BU-CY, N = 24). The substitution of BU for ATG was motivated by the high cost of ATG. There were no differences in the clinical features between the two groups, including age, gender, cytomegalovirus status, ABO match, interval between diagnosis and transplant, and number of total nucleated cells infused. No differences were observed in the time to neutrophil and platelet engraftment, or in the risk of veno-occlusive disease and hemorrhage. However, there was a higher risk of mucositis in the BU-CY group (71 vs 24%, P = 0.004). There were no differences in the incidence of neutrophil and platelet engraftment, acute and chronic graft-versus-host disease, and transplant-related mortality. There was a higher incidence of late rejection in the ATG-CY group (41 vs 4%, P = 0.009). Although the ATG-CY group had a longer follow-up (101 months) than the BU-CY group (67 months, P = 0.04), overall survival was similar between the groups (69 vs 58%, respectively, P = 0.32). We conclude that the association BU-CY is a feasible option to the conventional ATG-CY regimen in this population.

Bradykinin-related peptides from Phyllomedusa hypochondrialis

Bradykinin related peptides (BRPs) present in the water-soluble secretion and freshly dissected skin fragments of Phyllomedusa hypochondrialis were investigated by mass spectrometry techniques. Eighteen BRPs, along with their post-translational modifications, were characterized in the secretion by de novo MS/MS sequencing and direct MALDI imaging experiments of the frog skin. These molecules revealed strong sequence similarities to the main plasma kinin of some mammals and reptiles. Such a diversity of molecules, within the same peptide family, belonging to a single amphibian species may be related to functional specializations of these peptides and a variety of corresponding receptors that might be present in a number of different predators. Also, a novel analog, [Val]1,[Thr]6-bradykinyl-Gln,Ser had its biological activity positively detected in cell culture expressing the human bradykinin B2 receptor and in guinea pig ileum preparations.

Effects of 2% chlorhexidine and 5.25% sodium hypochlorite on gutta-percha cones studied by atomic force microscopy

AIM

To compare the effects of 2% chlorhexidine (CHX) and 5.25% sodium hypochlorite (NaOCl) on gutta-percha (GP) cone structure using atomic force microscopy (AFM).

METHODOLOGY

Two standardized GP cones were sectioned 3 mm from the tip, attached to a glass base and immersed in 2% CHX or 5.25% NaOCl for 1, 5, 10, 20 and 30 min. Untreated GP cones were used as control. Topography and elasticity analyses were performed on 12 different regions located between 1 and 2 mm from the tip. Root mean square (RMS) parameters for contact mode imaging and force modulation microscopy variations were measured. The differences between RMS values were tested by anova with Fisher's protected LSD test for multiple comparisons.

RESULTS

There was no deterioration in the topography and physical properties studied when 2% CHX was used in comparison with the control (P < 0.05). The RMS parameter for topography increased after 10 min of 5.25% NaOCl exposure in comparison with the control (P < 0.05). In addition, 5.25% NaOCl increased the elasticity of the GP cone after an immersion time of 1 min in comparison with the control (P < 0.05).

CONCLUSIONS

Two per cent CHX did not change GP cone structure following up to 30 min exposure. Conversely, 5.25% NaOCl caused elastic changes after 1 min exposure.

Effect of bullfrog (Rana catesbeiana) oil administered by gavage on the fatty acid composition and oxidative stress of mouse liver

The aim of the present study was to investigate the effects of daily intragastric administration of bullfrog oil (oleic, linoleic and palmitoleic acid-rich oil), corresponding to 0.4% of body weight for four weeks, on fatty acid composition and oxidative stress (lipid peroxidation and catalase activity) in mouse liver. The activities of aspartate aminotransferase (AST), alkaline phosphatase (ALP), alanine aminotransferase (ALT), and gamma-glutamyltransferase (GGT), biomarkers of tissue injury, were determined in liver homogenates and serum. The proportions of 18:2n-6, 20:4n-6, 20:5n-3, and 22:6n-3 (polyunsaturated fatty acids, from 37 to 60%) in the total fatty acid content were increased in the liver of the bullfrog oil-treated group (P < 0.05) compared to control. At the same time, a significant decrease in the relative abundance of 14:0, 16:0, and 18:0 (saturated fatty acids, from 49 to 25%) was observed. The hepatic content of thiobarbituric acid reactive substances (TBARS) was increased from 2.3 +/- 0.2 to 12.3 +/- 0.3 nmol TBA-MDA/mg protein and catalase activity was increased from 840 +/- 32 to 1110 +/- 45 micromol reduced H2O2 min-1 mg protein-1 in the treated group. Bullfrog oil administration increased AST and ALP activities in the liver (from 234.10 +/- 0.12 to 342.84 +/- 0.13 and 9.38 +/- 0.60 to 20.06 +/- 0.27 U/g, respectively) and in serum (from 95.41 +/- 6.13 to 120.32 +/- 3.15 and 234.75 +/- 11.5 to 254.41 +/- 2.73 U/l, respectively), suggesting that this treatment induced tissue damage. ALT activity was increased from 287.28 +/- 0.29 to 315.98 +/- 0.34 U/g in the liver but remained unchanged in serum, whereas the GGT activity was not affected by bullfrog oil treatment. Therefore, despite the interesting modulation of fatty acids by bullfrog oil, a possible therapeutic use requires care since some adverse effects were observed in liver.

[Analysis of nitrocompound pesticides by potentiography (author's transl)]

This paper describes a potentiographic technique developed for determining nitrocompound pesticides. The statistical analysis of the results showed that it is precise and accurate. Rapidity is another important characteristic of the developed potentiographic technique. It is not specific and for that in some cases a column chromatographic cleanup is necessary.