The presence of contaminants such as aflatoxins (AFs) in dairy products constitutes a serious risk to the health of consumers, especially children who are most sensitive to the adverse effects of ...AFs. The presence of Aflatoxin M1 (AFM1) in milk is a public health problem since dairy products are massively consumed worldwide. The aim of the present work was to select microorganisms capable of reducing AFM1 entry into the food chain through adsorption/degradation strategies. Moreover, the toxicity of AFM1 degradation products was evaluated. All tested strains had the capacity to adsorb 19%–61% AFM1 in milk. These strains also had the ability to degrade AFM1 into metabolites less toxic than the original toxin. Moreover, this is the first study to report harmless and probiotic Pediococcus pentosaceus and Kluveromyces marxianus have the ability to adsorb and degrade AFM1 to less toxic metabolites in milk.
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•P. pentosaceus RC006 and K. marxianus VM003 had the ability to adsorb AFM1 in milk.•P. pentosaceus RC006 and K. marxianus VM003 had the ability to degrade AFM1 in milk.•Lactic Acid Bacteria and yeast strains reduced AFM1 to less toxic metabolites in milk.
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•A biodegradable biopolymeric matrix of chitosan-starch was developed.•Steam sterilization of the matrix increased its swelling equilibrium.•Macrobeads supported the survival of ...bacteria at high levels for more than a year.•Bacterial release from macrospheres was gradual both in water and soil.•The developed material showed potential as a support for biofertilizers.
The study examines the use of macrobeads for the controlled-release of bacteria. Macrobeads were prepared by an easy dripping-technique using 20/80 wt/wt chitosan-starch blends and sodium tripolyphosphate as cross-linking agent. The resulting polymeric matrix was examined by SEM, XRD, TGA, and solid-RMN. The swelling-equilibrium, thermal behaviour, crystallinity, and size of macrobeads were affected by the autoclave-sterilization. The diameter of the sterilized xerogel was c.a. 1.6 mm. The results suggested that ionotropic-gelation and neutralization were the mechanisms underlying hydrogel formation. Plant growth-promoting bacteria (PGPB) were loaded into macrobeads separately or co-inoculated. Bacteria loaded macrobeads were dried and stored. Bacteria survived at least 12 months in orders of 109 CFU of A. brasilense/g and 108 CFU of P. fluorescens/g. Bacterial release in sterile saline solution tended to a super Case-II transport mechanism. Polymeric-matrix release efficiently both PGPB in natural soils, which uncovers their potential for the formulation of novel and improved biofertilizers.
Climate change affects water resources worldwide, and Southern Europe is one of the areas where water scarcity is expected to increase in the future. Different water scarcity indicators discussed in ...this manuscript (e.g. total annual actual renewable water resources, water exploitation index and dependency ratio) showed that some parts of this region are already facing water stress and that climate change could have a great impact on their water supply sector. As agriculture is the biggest consumer of water in the world and also in this particular region, potential water scarcity will impose the need to find new water sources. Treated wastewater reuse would decrease the pressure on the environment and is especially suitable for reuse in agriculture since it already contains some nutrients required for plant growth. However, in order to use it safely, treated wastewater must reach a certain quality that should be regulated. In the south of Europe, 4 countries out of 15 have already adopted wastewater reuse regulations (Greece, Italy, Portugal and Spain). This review compares these regulations and discusses their differences.
Zearalenone, an oestogenic mycotoxin produced by Fusarium sp., occurs naturally in agricultural commodities. Economic losses and health concerns associated to mycotoxins has attracted research ...interest towards exploring novel approaches to detoxify mycotoxin-contaminated food and feed. The aim of the present work was to study the ability of 11 aflatoxin-degrading Bacillus strains to degrade ZEA. In addition, a qualitative assessment of protease, amylase and cellulase activity of the studied Bacillus strains was made. All strains were able to degrade 58–96.9% ZEA after 72 h. Toxicity towards Artemia salina was significantly reduced (P < 0.0001). Degradation extracts fluorescence decreased 50% indicating a probable cleavage of the lactone ring. Strains RC1A, RC3A and RC6A showed a remarkable enzymatic activity, showing potential to be used as feed additives.
•AFB1-degrading Bacillus sp. strains also degrade ZEA in vitro.•ZEA degradation by Bacillus sp. reduced ZEA toxicity towards A. salina.•Bacillus sp. demonstrated protease, amylase and cellulase activity.
ABSTRACT
We derive limits on any electromagnetic counterpart to the compact binary merger S190814bv, whose parameters are consistent with the merger of a black hole and a neutron star. We present ...observations with the new wide-field optical imager DDOTI and also consider Swift/BAT observations reported by Palmer et al. We show that Swift/BAT would have detected a counterpart with similar properties to a typical on-axis short GRB at the 98 per cent confidence level, whereas our DDOTI observations only rule out such a counterpart at the 27 per cent confidence level. Neither has sufficient sensitivity to rule out an off-axis counterpart like GW 170817. We compare the efficiency of Swift/BAT and DDOTI for future observations, and show that DDOTI is likely to be about twice as efficient as Swift/BAT for off-axis events up to about 100 Mpc.
Abstract
Azospirillum brasilense is a rhizobacterium that provides beneficial effects on plants when they colonize roots. The formation of complex bacterial communities known as biofilms begins with ...the interaction of planktonic cells with surfaces in response to appropriate signals. Nitric oxide (NO) is a signaling molecule implicated in numerous processes in bacteria, including biofilm formation or dispersion, depending on genera and lifestyle. Azospirillum brasilense Sp245 produces NO by denitrification having a role in root growth promotion. We analyzed the role of endogenously produced NO on biofilm formation in A. brasilense Sp245 and in a periplasmic nitrate reductase mutant (napA::Tn5; Faj164) affected in NO production. Cells were statically grown in media with nitrate or ammonium as nitrogen sources and examined for biofilm formation using crystal violet and by confocal laser microscopy. Both strains formed biofilms, but the mutant produced less than half compared with the wild type in nitrate medium showing impaired nitrite production in this condition. NO measurements in biofilm confirmed lower values in the mutant strain. The addition of a NO donor showed that NO influences biofilm formation in a dose-dependent manner and reverses the mutant phenotype, indicating that Nap positively regulates the formation of biofilm in A. brasilense Sp245.
Fungi and mycotoxins in silage: an overview Alonso, V.A.; Pereyra, C.M.; Keller, L.A.M. ...
Journal of applied microbiology,
September 2013, Letnik:
115, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Summary
The present revision shows the early and current knowledge in the field of silage fungi and mycotoxins explaining the relevance of fungi and mycotoxins in silage. The problem does not end in ...animal disease or production losses as mycotoxins in feed can lead to the presence of their metabolic products in dairy products, which will be eventually affecting human health, mainly infants. Silage is green forage preserved by lactic fermentation under anaerobic conditions. This ecosystem maintains its quality and nutritional value depending on interactions among physical, chemical and biological agents. Forages used for ensilage are naturally in contact with yeasts and filamentous fungi, and the contamination often occurs in the field and can also occur during harvesting, transport, storage. Moreover, postharvest poor management can lead to a rapid spoilage. Studies on fungal contamination of dairy cattle feed have shown how corn silage influences the contamination degree of feed supplied to livestock. Increasing knowledge in this area will help elucidate the influence that this microbiota exerts on production and/or degradation of mycotoxins present in silage. Some of these fungi, although opportunist pathogens, are relevant epidemiologically and represent a high risk of contamination to farm workers who handle them improperly.
Microbial degradation of aflatoxins (AFs) is an alternative to the use of mycotoxin binders. The lactone ring is a possible target for microbial enzymes and its cleavage reduces AFs toxicity. The aim ...of this study was to isolate and identify Bacillus strains able to degrade AFB1 to less toxic metabolites and to identify aiiA genes encoding for N-acyl-homoserine lactone (AHL) lactonase to possibly correlate detoxification with the production of this enzyme. Eleven soilborne Bacillus strains were isolated and identified by MALDI-TOF MS. Ten cultures and eight cell free culture supernatants (CFCS) were able to significantly (P < 0.05) degrade 27.78–79.78% AFB1. Cell lysates were also able to degrade AFB1 (P < 0.05). Exposure to 70 and 80 °C did not affect enzyme activity. Aflatoxin B1 toxicity towards Artemia salina was reduced after degradation by each of the Bacillus strains. B. subtilis RC1B, B. cereus RC1C and B. mojavensis RC3B, amplified a fragment of 753 pb corresponding to the aiiA gene encoding for AHL lactonase. AFB1 degradation by the strains tested was due to the extracellular and intracellular enzymes. If demonstrated to be safe, these could be used to detoxify AFB1 in contaminated food or feed.
•Bacillus strains isolated from soil and pond mud degraded AFB1.•aiiA genes encoding for N-acyl-homoserine lactone (AHL) lactonase were present in 3 of the strains.•The degradation activity of Bacillus strains was due to the extracellular as well as intracellular enzymes.
This study presents for the first time results about the microplastic concentration and their origin in a stream of the Pampas region in Argentina, receiving wastewater of an intermediate city. The ...most appropriate procedure to analyze and quantify the microplastics in the studied system is the use of an oxidative digestion process using a 30% H2O2 solution to eliminate the organic matter in the samples. A high quantity of MPs, on the order of millions of microplastics per m3 of water, was estimated in the Langueyú stream. 56% of the microplastics correspond to fibers with diameters between 10 and 15 μm and lengths less than 500 μm, while 44% are fragments with sizes of tens of micrometers. Raman microspectroscopy was used to identify the type of fibers. The characteristics of the microplastic fibers released in a wash load test are comparable with those observed in the Langueyú stream, in particular, the average sizes and the distribution of the diameters of the MPFs are similar. The processes in the sewage treatment plant, prior to their discharge in the stream, would affect the color of the fibers and their length.
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•An analysis of microplastics found in a Pampas region stream in Argentina was done.•A high quantity of microplastics, on the order of millions per m3, was estimated.•56% is microplastic fibers with predominance of PET and diameters of 10–15 μm.•Fibers released in a wash load test are comparable with those observed in the stream.
ErbB-2 amplification/overexpression accounts for an aggressive breast cancer (BC) subtype (ErbB-2-positive). Enhanced ErbB-2 expression was also found in gastric cancer (GC) and has been correlated ...with poor clinical outcome. The ErbB-2-targeted therapies trastuzumab (TZ), a monoclonal antibody, and lapatinib, a tyrosine kinase inhibitor, have proved highly beneficial. However, resistance to such therapies remains a major clinical challenge. We here revealed a novel mechanism underlying the antiproliferative effects of both agents in ErbB-2-positive BC and GC. TZ and lapatinib ability to block extracellular signal-regulated kinases 1/2 and phosphatidylinositol-3 kinase (PI3K)/AKT in sensitive cells inhibits c-Myc activation, which results in upregulation of miR-16. Forced expression of miR-16 inhibited in vitro proliferation in BC and GC cells, both sensitive and resistant to TZ and lapatinib, as well as in a preclinical BC model resistant to these agents. This reveals miR-16 role as tumor suppressor in ErbB-2-positive BC and GC. Using genome-wide expression studies and miRNA target prediction algorithms, we identified cyclin J and far upstream element-binding protein 1 (FUBP1) as novel miR-16 targets, which mediate miR-16 antiproliferative effects. Supporting the clinical relevance of our results, we found that high levels of miR-16 and low or null FUBP1 expression correlate with TZ response in ErbB-2-positive primary BCs. These findings highlight a potential role of miR-16 and FUBP1 as biomarkers of sensitivity to TZ therapy. Furthermore, we revealed miR-16 as an innovative therapeutic agent for TZ- and lapatinib-resistant ErbB-2-positive BC and GC.
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