The anti-inflammatory effects and cellular transport mechanisms of all-E-astaxanthin and its 9Z- and 13Z-isomers were investigated in a Caco-2 cell monolayer model. All three astaxanthin isomers at ...1.2 μM significantly reduced the TNF-α-induced secretion of IL-8 by 22–27%. Z-Astaxanthins, especially 9Z-astaxanthin exhibited greater anti-inflammatory effect than all-E-astaxanthin by down-regulating pro-inflammatory cytokines COX-2 and TNF-α gene expression to 0.88 ± 0.01-fold and 0.83 ± 0.17-fold that of the negative control (NC), respectively. The anti-inflammatory effects of astaxanthin isomers were achieved via modulating the NF-κB signaling pathway as they down-regulated TNF-α-induced phosphorylation of IκBα from 5.3 ± 0.19-fold to 3.8 ± 0.33–4.5 ± 0.27-fold of NC. The scavenger receptor class B type I protein (SR-BI) was found to facilitate the cellular uptake of astaxanthin isomers. Its inhibitor (BLT-1) and antibody (Anti-SRBI) significantly reduced cellular uptake efficiency of all-E-astaxanthin (18.9% and 16.7%, respectively) and 13Z-astaxanthin (28.8% and 30.2%, respectively), but not of 9Z-astaxanthin. The molecular docking experiment showed that 13Z-astaxanthin had significantly higher affinity with SR-BI (atomic contact energy: −420.31) than all-E-astaxanthin and 9Z-astaxanthin, which at least partially supports the higher bioavailability of 13Z-astaxanthin observed in vivo by others.
Antimicrobial resistance is among the most urgent global challenges facing sustainable animal production systems. The use of antibiotics as growth promoters and for infectious disease prevention in ...intensive animal-farming practices has translated into the selection and spread of antimicrobial resistance genes in an unprecedented fashion. Several multi-resistant bacterial strains have been isolated from food-producing animals, thus constituting an alarming food-safety issue. Many industrial byproducts with potential antimicrobial properties are currently being investigated to identify empirical and affordable solutions/alternatives that can potentially be used in feed for animals. Grape pomace is among such byproducts that gained the attention as a result of its low cost, abundance, and, most importantly, its bioactive and antibacterial properties. This review discusses the recently reported studies with regard to exploring the use of grape pomace (and its extracts) in animal production to control pathogens, along with the promotion of beneficial bacterial species in the gut to ultimately alleviate antibacterial resistance. The review further summarizes realistic expectations connected with grape pomace usage and lists the still-to-be-addressed concerns about its application in animal agriculture.
Mycotoxins, the secondary metabolites of mycotoxigenic fungi, have been found in almost all agricultural commodities worldwide, causing enormous economic losses in livestock production and severe ...human health problems. Compared to traditional physical adsorption and chemical reactions, interest in biological detoxification methods that are environmentally sound, safe and highly efficient has seen a significant increase in recent years. However, researchers in this field have been facing tremendous unexpected challenges and are eager to find solutions. This review summarizes and assesses the research strategies and methodologies in each phase of the development of microbiological solutions for mycotoxin mitigation. These include screening of functional microbial consortia from natural samples, isolation and identification of single colonies with biotransformation activity, investigation of the physiological characteristics of isolated strains, identification and assessment of the toxicities of biotransformation products, purification of functional enzymes and the application of mycotoxin decontamination to feed/food production. A full understanding and appropriate application of this tool box should be helpful towards the development of novel microbiological solutions on mycotoxin detoxification.
•Novel patented techniques to detoxify the mycotoxins in animal feeds were reviewed.•Detoxification methods target pre-harvest, post-harvest, or finished products.•Physical adsorption and ...biotransformation are two main strategies on detoxification.•Biotransformation related enzymes and genes represent the trend of innovations.
Mycotoxins are secondary metabolites produced by specific fungi that can be found throughout the dietary chain of animal feed. Among the agriculturally important mycotoxins are: aflatoxin B1 (AFB1), deoxynivalenol (DON), zearalenone (ZEA), nivalenol (NIV), fumonisin B1 (FUB1), ochratoxin A (OTA), citrinin (CIT) and patulin (PAT). Economic losses and health concerns caused by increased frequencies of mycotoxin contaminations have attracted research interests toward exploring new inactivation and detoxification methods. Suggested strategies of decontamination include eliminating mycotoxins from contaminated grains, decreasing the bioavailability of such mycotoxins in the gastrointestinal tracts of animals, or directly degrading mycotoxins in feeds. Based on these points of action, a number of approaches such as adsorption, chemical treatment, and bio-transformation by catabolizing microorganisms/enzymes have been developed and optimized. This review summarizes the detoxification techniques and industrial applications (granted and pending patents) reported in the last five years (2010–2015). A clear understanding of such novel detoxification methods and development-trends can be beneficial to the feed and livestock industry and will contribute to assuring pre- and post-harvest management and processing practices are in place that maximizes the consumers’ safety and profits of livestock and related industries.
Deoxynivalenol (DON) is one of the most common mycotoxins found in cereal grains and grains contaminated with DON can cause health issues for both humans and animals and result in severe economic ...losses. Currently there is no feasible method to remediate affected grains. The development of a biological method for detoxification is becoming increasingly more plausible with the discovery of microbes which can transform DON to a relatively non-toxic stereoisomer, 3-
-DON. Although bacteria capable of detoxifying DON have been known for some time, it is only recently an enzyme responsible was identified. In
17-2-E-8 (
sp. 17-2-E-8) a two-step DON epimerization (Dep) pathway, designated as the Dep system, completes this reaction. DepA was recently identified as the enzyme responsible for the conversion of DON to 3-keto-DON, and in this report, DepB, a NADPH dependent dehydrogenase, is identified as the second and final step in the pathway. DepB readily catalyzes the reduction of 3-keto-DON to 3-
-DON. DepB is shown to be moderately thermostable as it did not lose significant activity after a heat treatment at 55°C and it is amenable to lyophilization. DepB functions at a range of pH-values (5-9) and functions equally well in multiple common buffers. DepB is clearly a NADPH dependent enzyme as it utilizes it much more efficiently than NADH. The discovery of the final step in the Dep pathway may provide a means to finally mitigate the losses from DON contamination in cereal grains through an enzymatic detoxification system. The further development of this system will need to focus on the activity of the Dep enzymes under conditions mimicking industrially relevant conditions to test their functionality for use in areas such as corn milling, fuel ethanol fermentation or directly in animal feed.
Summary
The biological detoxification of mycotoxins, including deoxynivalenol (DON), represents a very promising approach to address the challenging problem of cereal grain contamination. The recent ...discovery of Devosia mutans 17‐2‐E‐8 (Devosia spp. 17‐2‐E‐8), a bacterial isolate capable of transforming DON to the non‐toxic stereoisomer 3‐epi‐deoxynivalenol, along with earlier reports of bacterial species capable of oxidizing DON to 3‐keto‐DON, has generated interest in the possible mechanism and enzyme(s) involved. An understanding of these details could pave the way for novel strategies to manage this widely present toxin. It was previously shown that DON epimerization proceeds through a two‐step biocatalysis. Significantly, this report describes the identification of the first enzymatic step in this pathway. The enzyme, a dehydrogenase responsible for the selective oxidation of DON at the C3 position, was shown to readily convert DON to 3‐keto‐DON, a less toxic intermediate in the DON epimerization pathway. Furthermore, this study provides insights into the PQQ dependence of the enzyme. This enzyme may be part of a feasible strategy for DON mitigation within the near future.
This report describes the discovery of a dehydrogenase responsible for the selective oxidation of mycotoxin deoxynivalenol (DON) at the C3 position. The enzyme was shown to readily convert DON to 3‐keto‐DON, a less toxic intermediate in the DON epimerization pathway. This enzyme may be part of a feasible strategy for DON mitigation within the near future.
Recombinant proteins are becoming increasingly important for industrial applications, where
is the most widely used bacterial host for their production. However, the formation of inclusion bodies is ...a frequently encountered challenge for producing soluble and functional recombinant proteins. To overcome this hurdle, different strategies have been developed through adjusting growth conditions, engineering host strains of
, altering expression vectors, and modifying the proteins of interest. These approaches will be comprehensively highlighted with some of the new developments in this review. Additionally, the unique features of protein inclusion bodies, the mechanism and influencing factors of their formation, and their potential advantages will also be discussed.
The enzymatic detoxification of deoxynivalenol (DON) is a promising mitigation strategy for addressing this mycotoxin contamination of cereal grains. A recently described bacterium, Devosia mutans ...17-2-E-8, capable of transforming DON into its non-toxic stereoisomer 3-epi-DON, holds promise for the development of such applications. Earlier observations suggested that DON epimerization proceeds via a two-step catalysis with 3-keto-DON as an intermediate. The results of this study indicate that NADPH is required for DON epimerization by cell-free protein extracts of D. mutans, while high concentrations of glucose and sucrose have a suppressive effect. Chemically synthesized 3-keto-DON incubated with D. mutans protein fractions enriched by ammonium sulfate precipitation at 35-55% saturation selectively reduced 3-keto-DON to 3-epi-DON, but fell short of supporting the complete epimerization of DON. In addition, seven Devosia species investigated for DON epimerization were all able to reduce 3-keto-DON to 3-epi-DON, but only a few were capable of epimerizing DON. The above observations collectively confirm that the enzymes responsible for the oxidation of DON to 3-keto-DON are physically separate from those involved in 3-keto-DON reduction to 3-epi-DON. The enzymatic nature of DON epimerization suggests that the process could be used to develop genetically engineered crops or microorganisms, ultimately reducing foodborne exposure of consumers and farm animals to DON.
Deoxynivalenol (DON) is a secondary fungal metabolite that is associated with many adverse toxicological effects in agriculture as well as human/animal nutrition. Bioremediation efforts in recent ...years have led to the discovery of numerous bacterial isolates that can transform DON to less toxic derivatives. Both 3-keto-DON and 3-epi-DON were recently shown to exhibit reduced toxicity, compared to DON, when tested using different cell lines and mammalian models. In the current study, the toxicological assessment of 3-keto-DON and 3-epi-DON using in planta models surprisingly revealed that 3-keto-DON, but not 3-epi-DON, retained its toxicity to a large extent in both duckweeds (Lemna minor L.) and common wheat (Triticum aestivum L.) model systems. RNA-Seq analysis revealed that the exposure of L. minor to 3-keto-DON and DON resulted in substantial transcriptomic changes and similar gene expression profiles, whereas 3-epi-DON did not. These novel findings are pivotal for understanding the environmental burden of the above metabolites as well as informing the development of future transgenic plant applications. Collectively, they emphasize the fundamental need to assess both plant and animal models when evaluating metabolites/host interactions.
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