Aldosterone is produced by adrenocortical zona glomerulosa (AZG) cells in response to angiotensin II (AngII) acting through its type I receptors (AT
Rs). AT
R is a G protein-coupled receptor (GPCR) ...that induces aldosterone via both G proteins and the adapter protein βarrestin1, which binds the receptor following its phosphorylation by GPCR-kinases (GRKs) to initiate G protein-independent signaling. β-adrenergic receptors (ARs) also induce aldosterone production in AZG cells. Herein, we investigated whether GRK2 or GRK5, the two major adrenal GRKs, is involved in the catecholaminergic regulation of AngII-dependent aldosterone production. In human AZG (H295R) cells in vitro, the βAR agonist isoproterenol significantly augmented both AngII-dependent aldosterone secretion and synthesis, as measured by the steroidogenic acute regulatory (StAR) protein and CYP11B2 (aldosterone synthase) mRNA inductions. Importantly, GRK2, but not GRK5, was indispensable for the βAR-mediated enhancement of aldosterone in response to AngII. Specifically, GRK2 inhibition with Cmpd101 abolished isoproterenol's effects on AngII-induced aldosterone synthesis/secretion, whereas the GRK5 knockout via CRISPR/Cas9 had no effect. It is worth noting that these findings were confirmed in vivo, since rats overexpressing GRK2, but not GRK5, in their adrenals had elevated circulating aldosterone levels compared to the control animals. However, treatment with the β-blocker propranolol prevented hyperaldosteronism in the adrenal GRK2-overexpressing rats. In conclusion, GRK2 mediates a βAR-AT
R signaling crosstalk in the adrenal cortex leading to elevated aldosterone production. This suggests that adrenal GRK2 may be a molecular link connecting the sympathetic nervous and renin-angiotensin systems at the level of the adrenal cortex and that its inhibition might be therapeutically advantageous in hyperaldosteronism-related conditions.
Toxigenic Aspergillus flavus and A. parasiticus fungal strains can contaminate a wide variety of food crops with the subsequent production of aflatoxins (AFs) resulting in severe economic losses and ...public health issues. Biological control is a promising approach to manage AFs contamination in pre- and post-harvested crops. In the present study, the effect of soil-borne Bacillus spp. strains on aflatoxigenic A. parasiticus growth and AFs production was evaluated and the culture supernatant of the most effective strain was evaluated for the presence of antifungal lipopeptides. Six Bacillus spp. strains were able to reduce A. parasiticus growth rate significantly (p < 0.05). Bacillus spp. RC1A was able to inhibit fungal growth almost completely, reducing growth rate to 0.16 mm/h and increasing Lag phase duration (31.72 h) (p < 0.0001). RC1A could also reduce AFB1 concentration produced by A. parasiticus (p < 0.0001). Organic solvent extraction and chromatographic analysis of RC1A culture supernatant showed the presence of bands corresponding to three of the main groups of lipopeptides (surfactin, iturin A and fengycin) at the expected retention factor (Rf) values; they were also confirmed by MALDI-MS analysis. These fractions were able to inhibit A. parasiticus growth and AFB1 production to non-detectable levels when tested separately in liquid culture media. The further study of the antifungal compounds produced by these strains will determine their potential use to manage AFs contamination in crops and feeds.
•Bacillus strains reduced Aspergillus parasiticus growth and AFB1 production.•Bacillus mojavensis RC1A showed the best inhibition.•Different antifungal lipopeptidic compounds were extracted from B. mojavensis RC1A.•Fengycines, iturins, surfactins and bacillomycins were produced by RC1A and RC6A.
The storage of barley rootlets is increasingly employed to provide raw material for pig feeding in Brazil. Barley rootlets represent an important feedstuff for animal production due to their high ...levels of protein and fiber, and low price. However, poor management of raw materials during storage can result in fungal growth, the loss of nutritive substances and contamination by mycotoxins. The aims of this work were (1) to identify fungi associated with barley rootlets used as pig feedstuff raw material, and (2) to identify and quantify selected mycotoxins naturally produced by isolated mycotoxin-producing species in this substrate over a year. Samples were examined for fungal counts and genera distribution. Fumonisin B
1 and aflatoxin B
1 contamination were determined using high pressure liquid chromatography (HPLC). Barley rootlet samples were of low hygienic quality. Although a broad survey was undertaken, low fungal diversity was found.
Fusarium verticillioides was the most prevalent species followed by
Aspergillus flavus. Despite
Aspergillus clavatus being widely associated with high-moisture sprouted grains including brewers’ grains, and causing toxicity to livestock, it was not detected in this work. Although pre-harvest contamination of the barley crop, as in the maize, could occur, the barley might support
F. verticillioides/
Fusarium proliferatum growth when grain is remoistened during the germination and malting process and it might even continue during storage on pig farms. All samples were positive for fumonisin B
1 whereas aflatoxin B
1 contamination was not detected. It is important to point out the potential risk of fumonisin contamination in barley rootlets used as animal feed.
Fusarium toxins are important not so much for their acute effects as for the chronic syndromes reported worldwide. The obtained results reveal the need for periodic monitoring of raw materials to avoid problems in animal production and hazards to animal and human health.
ABSTRACT
We present optical and near-infrared (NIR) photometric observations of GRB 191016 with the COATLI,DDOTI, and RATIR ground-based telescopes over the first three nights. We present the ...temporal evolution of the optical afterglow and describe five different stages that were not completely characterized in previous works, mainly due to scarcity of data points to accurately fit the different components of the optical emission. After the end of the prompt gamma-ray emission, we observed the afterglow rise slowly in the optical and NIR wavelengths and peak at around T + 1450 s in all filters. This was followed by an early decay, a clear plateau from T + 5000 s to T + 11 000 s, and then a regular late decay. We also present evidence of the jet break at later times, with a temporal index in good agreement with the temporal slope obtained from X-ray observations. Although many of the features observed in the optical light curves of gamma-ray bursts are usually well explained by a reverse shock (RS) or forward shock (FS), the shallowness of the optical rise and enhanced peak emission in the GRB 191016A afterglow is not well fitted by only a FS or a RS. We propose a theoretical model which considers both of these components and combines an evolving FS with a later embedded RS and a subsequent late energy injection from the central engine activity. We use this model to successfully explain the temporal evolution of the light curves and discuss its implications on the fireball properties.
ABSTRACT
We collected the optical light-curve data of 227 gamma-ray bursts (GRBs) observed with the TAROT, COATLI, and RATIR telescopes. These consist of 133 detections and 94 upper limits. We ...constructed average light curves in the observer and rest frames in both X-rays (from Swift/X-Ray Telescope) and the optical. Our analysis focused on investigating the observational and intrinsic properties of GRBs. Specifically, we examined observational properties, such as the optical brightness function of the GRBs at T = 1000 s after the trigger, as well as the temporal slope of the afterglow. We also estimated the redshift distribution for the GRBs within our sample. Of the 227 GRBs analysed, we found that 116 had a measured redshift. Based on these data, we calculated a local rate of ρ0 = 0.2 Gpc−3 yr−1 for these events with z < 1. To explore the intrinsic properties of GRBs, we examined the average X-ray and optical light curves in the rest frame. We use the afterglowpy library to generate synthetic curves to constrain the parameters typical of the bright GRB jet, such as energy (〈E0〉 ∼ 1053.6 erg), opening angle (〈θcore〉 ∼ 0.2 rad), and density (〈n0〉 ∼ 10−2.1 cm−3). Furthermore, we analyse microphysical parameters, including the fraction of thermal energy in accelerated electrons (〈ϵe〉 ∼ 10−1.37) and in the magnetic field (〈ϵB〉 ∼ 10−2.26), and the power-law index of the population of non-thermal electrons (〈p〉 ∼ 2.2).
Aims: To evaluate mycobiota and aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2) and fumonisin B1 (FB1) contamination in different malted barley types and brands and brewer’s grain collected ...from a major Argentinean brewery. Methods and Results: Total fungal counts were performed using the plate count method. Aflatoxin B1, AFB2, AFG1, AFG2 and Zearalenone (ZEA) analyses were performed by thin‐layer chromatography (TLC). Fumonisin B1 was determined by HPLC. Eighty‐three percentage of the malted barley (100% M1, 50% M2 and 100% M3) and 61% of brewer’s grain samples had a count >1 × 104 CFU g−1. Yeasts were isolated from all malt and brewer’s grain samples. Genera containing some of the most important mycotoxin producer species –Fusarium ssp., Aspergillus ssp., Penicillium ssp. and Alternaria ssp. – were isolated from the analysed samples, along with other environmental saprophytic fungi such as Geotrichum ssp., Mucorales and Cladosporium ssp. All samples were contaminated with 104–145 μg kg−1 FB1. Eighteen per cent of brewer’s grain samples were contaminated with 19–44·52 μg kg−1 AFB1. Aflatoxin B2, AFG1, AFG2 and ZEA were not detected in any of the analysed samples. Conclusions: Fungal and mycotoxin contamination in malt and brewer’s grain is an actual risk for animal and human health. Significance and Impact of the Study: This study may be useful for assessing the risk of mycotoxins in Argentinean beers and especially in animal feeds.
•Patch size, isolation and edge effect are the main indicators used in the literature.•Habitat fragmentation differentially affected fungal functional groups.•Landscape heterogeneity and multi-scale ...analysis should be considered.
Fungi are organisms with important roles in ecosystem functioning and services, but knowledge about how habitat fragmentation affect fungal diversity is biased by experimental approaches and it is spread in different trophic groups. We analyzed the empirical evidences of fungal diversity in fragmented landscapes, and proposed future perspectives for the study of these organisms under land use changes. Fungal diversity might be negatively affected by habitat fragmentation; however, this trend may differ in magnitude depending on fungal groups and their nutritional habits. In addition, due to the fact that fungal diversity at fragmented landscapes has been studied mainly through few indicators (e.g. isolation, area and edge effect); we propose incorporating the landscape structure and accurate spatio-temporal scales to the study of fungal diversity responses to fragmented landscapes. Together, this methodological refinement may allow improving knowledge on fungi when designing proper strategies for landscape management.
The genus Stenodema Laporte, 1832 is a group of grass-feeding plant bugs worldwide distributed, with five species recorded for the Subantarctic sub-region (sunsuMorrone 2015). Males of Stenodema ...longicuneata (Carvalho and Rosas, 1966) are redescribed and photographed. Stenodema laolaoensis (Carvalho, 1985) is proposed as a junior synonym of S. longicuneata. New geographic records are provided and distributional and biogeographic issues are discussed.
and
are the main cause of clinical mastitis in dairy cattle in Argentina, whereas coagulase-negative staphylococci (CNS) and environmental streptococci are the main cause of subclinical mastitis. ...Bacteria isolated from infected animals show increasing antimicrobial resistance.
This study aims to determine the antimicrobial resistance of staphylococci and streptococci isolated from milk with mastitis, and to genotypically characterize the methicillin-resistant (MR) staphylococci.
Isolation was performed on blood agar and identification was based on biochemical reactions. Antimicrobial susceptibility was according to the Clinical and Laboratory Standards Institute guidelines. The antimicrobial resistance genes, SCC
type and
type were detected by the polymerase chain reaction method.
We isolated a total of 185 staphylococci and 28 streptococci from 148 milk samples. Among the staphylococcal isolates, 154 were identified as CNS and 31 as
. Among the 154 CNS, 24.6% (n = 38) were resistant to penicillin, 14.9% (n = 23) to erythromycin, 17.5% (n = 27) to clindamycin, 6.5% (n = 10) to cefoxitin and oxacillin. Among the
isolates, 16.1% (n = 5) were resistant to penicillin, 3.2% (n = 1) to cefoxitin and oxacillin (MRSA). Six MR isolates (5 CNS and 1 MRSA) were positive to the
gene, and presented the SCC
IVa. The MRSA strain presented the sequence type 83 and the
type 002. Among the 28 streptococcal isolates, 14.3% (n = 4) were resistant to penicillin, 10.7% (n = 3) to erythromycin and 14.3% (n = 4) to clindamycin.
The present findings of this study indicate a development of antimicrobial resistance in main bacteria isolated from cows with mastitis in Argentina.
Aims
To in vitro evaluate the influence of the corn on the adsorption levels of aflatoxin B1 (AFB1) and zearalenone (ZEA) by yeast cell walls (YCWs).
Methods and Results
Two commercial YCWs were ...studied. The YCWs contain different percentages of polysaccharides. YCW1 and 2 contain 5·9 and 21% of mannans and 17·4 and 23% of β‐glucans, respectively. Each YCW was resuspended in pH 2 and pH 6 buffer solutions. Corn was used to study the matrix influence. An aliquot of 500 μl YCW suspension was added to each microtube containing 500 μl of 0·1, 0·25, 0·5, 1, 2·5 and 5 μg ml−1 AFB1 or 0·5, 5, 10, 20 and 50 μg ml−1 ZEA. Microtubes were kept with mechanical agitation at 37°C for 30 min and then centrifuged for 10 min at 16 873 g and; the supernatants were quantified by high‐pressure liquid chromatography. The amount of bound toxin was plotted as a function of the amount of added toxin according to mathematical expressions proposed by three theoretical models. Both YCWs were capable of adsorbing AFB1 and ZEA in amounts from 0·061 to 0·40 and from 0·10 and 0·26 g g−1, respectively. In the presence of the matrix, both adsorbents were not able to adsorb AFB1. However, they could adsorb ZEA at levels from 0·03 to 0·23 g g−1.
Conclusions
Both YCWs adsorbed ZEA in the presence of corn and also under simulated gastrointestinal pH conditions. These results suggest that the studied YCWs are potential candidates for ZEA adsorption.
Significance and Impact of the Study
Several in vitro assays have informed the ability of different substrates including yeast walls to adsorb AFB1 and ZEA; none of them have evaluated their ability to adsorb AFB1 and ZEA in the presence of the corn. The corn matrix can influence the adsorption phenomena of these mycotoxins.
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