Feeding Brassica vegetables to rats leads to the formation of characteristic DNA adducts (from 1-methoxy-3-indolylmethyl glucosinolate) in many tissues

Juices of Brassica vegetables are mutagenic and form characteristic DNA adducts in bacteria and mammalian cells. In this study, we examined whether such adducts are also formed in vivo in animal models. Rats fed raw broccoli ad libitum in addition to normal laboratory chow for 5 weeks showed one major adduct spot and sometimes an additional minor adduct spot in liver, kidney, lung, blood and the gastrointestinal tract, as determined by 32P-postlabelling/thin-layer chromatography. Adducts with the same chromatographic properties were formed when herring sperm DNA (or dG-3’-phosphate) was incubated with 1-methoxy-3-indolylmethyl glucosinolate (phytochemical present in Brassica plants), in the presence of myrosinase (plant enzyme that hydrolyses glucosinolates to bioactive breakdown products). UPLC–MS/MS analysis corroborated this finding: 1-Methoxy-3-indolylmethyl-substituted purine nucleosides were detected in the hepatic DNA of broccoli-fed animals, but not in control animals. Feeding raw cauliflower led to the formation of the same adducts. When steamed rather than raw broccoli was used, the adduct levels were essentially unchanged in liver and jejunum, but elevated in large intestine. Due to inactivation of myrosinase by the steaming, higher levels of the glucosinolates may have reached the large bowl to be activated by glucosidases from intestinal bacteria. In conclusion, the consumption of common Brassica vegetables can lead to the formation of substantial levels of DNA adducts in animal models. The adducts can be attributed to a specific phytochemical, neoglucobrassicin (1-methoxy-3-indolylmethyl glucosinolate).

Comparing the effect of tailwater replenishment at different time intervals on eutrophic surface freshwater: a mesocosm simulation study

Tailwater is becoming the main water source supplied to surface freshwater worldwide. However, few studies have been compared the effect of tailwater replenishment at different time intervals on eutrophic surface freshwater. In this study, we investigated the changes of water quality, sediment, and submerged macrophytes in eutrophic water in an outdoor mesocosm in response to different tailwater replenishment time intervals [every 7 days (TW7), 14 days (TW14) and 28 days (TW28)]. An 84-day simulation experiment demonstrated that there were only significant differences in total nitrogen (TN) concentration of overlying water, with the lowest mean value occurring in TW28. Nevertheless, the sediment TN was lowest in TW7 with a denitrification rate of 102.9 μmol/m2/h. Tailwater replenishment also increased the nitrogen content and total biomass of Vallisneria spiralis, and TW7 had the highest total biomass of 20.19 g. Additionally, tailwater replenishment also affected plant enzyme activity, causing an increase in superoxide dismutase, peroxidase, and catalase, coupled with a decrease in malondialdehyde concentration in the leaves. Overall, TW28 can be adopted as a tailwater replenishment strategy to ensure water quality, whereas TW7 can be applied without a strict water quality requirement for TN.

Activation and detoxification of cassava cyanogenic glucosides by the whitefly Bemisia tabaci

Two-component plant defenses such as cyanogenic glucosides are produced by many plant species, but phloem-feeding herbivores have long been thought not to activate these defenses due to their mode of feeding, which causes only minimal tissue damage. Here, however, we report that cyanogenic glycoside defenses from cassava (Manihot esculenta), a major staple crop in Africa, are activated during feeding by a pest insect, the whitefly Bemisia tabaci, and the resulting hydrogen cyanide is detoxified by conversion to beta-cyanoalanine. Additionally, B. tabaci was found to utilize two metabolic mechanisms to detoxify cyanogenic glucosides by conversion to non-activatable derivatives. First, the cyanogenic glycoside linamarin was glucosylated 1–4 times in succession in a reaction catalyzed by two B. tabaci glycoside hydrolase family 13 enzymes in vitro utilizing sucrose as a co-substrate. Second, both linamarin and the glucosylated linamarin derivatives were phosphorylated. Both phosphorylation and glucosidation of linamarin render this plant pro-toxin inert to the activating plant enzyme linamarase, and thus these metabolic transformations can be considered pre-emptive detoxification strategies to avoid cyanogenesis.

Drug Carriers Based on Graphene Oxide and Hydrogel: Opportunities and Challenges in Infection Control Tested by Amoxicillin Release

Graphene oxide (GO) was proposed as an efficient carrier of antibiotics. The model drug, amoxicillin (AMOX), was attached to GO using a peptide linker (Leu-Leu-Gly). GO-AMOX was dispersed in a hydrogel to which the enzyme responsible for releasing AMOX from GO was also added. The drug molecules were released by enzymatic hydrolysis of the peptide bond in the linker. As the selected enzyme, bromelain, a plant enzyme, was used. The antibacterial nature of the carrier was determined by its ability to inhibit the growth of the Enterococcus faecalis strain, which is one of the bacterial species responsible for periodontal and root canal diseases. The prepared carrier contained only biocompatible substances, and the confirmation of its lack of cytotoxicity was verified based on the mouse fibrosarcoma cell line WEHI 164. The proposed type of preparation, as a universal carrier of many different antibiotic molecules, can be considered as a suitable solution in the treatment of inflammation in dentistry.

Potential for Applying Continuous Directed Evolution to Plant Enzymes: An Exploratory Study

Plant evolution has produced enzymes that may not be optimal for maximizing yield and quality in today’s agricultural environments and plant biotechnology applications. By improving enzyme performance, it should be possible to alleviate constraints on yield and quality currently imposed by kinetic properties or enzyme instability. Enzymes can be optimized more quickly than naturally possible by applying directed evolution, which entails mutating a target gene in vitro and screening or selecting the mutated gene products for the desired characteristics. Continuous directed evolution is a more efficient and scalable version that accomplishes the mutagenesis and selection steps simultaneously in vivo via error-prone replication of the target gene and coupling of the host cell’s growth rate to the target gene’s function. However, published continuous systems require custom plasmid assembly, and convenient multipurpose platforms are not available. We discuss two systems suitable for continuous directed evolution of enzymes, OrthoRep in Saccharomyces cerevisiae and EvolvR in Escherichia coli, and our pilot efforts to adapt each system for high-throughput plant enzyme engineering. To test our modified systems, we used the thiamin synthesis enzyme THI4, previously identified as a prime candidate for improvement. Our adapted OrthoRep system shows promise for efficient plant enzyme engineering.

Potential For Applying Continuous Directed Evolution To Plant Enzymes

SUMMARYPlant evolution has produced enzymes that may not be optimal for maximizing yield and quality in today’s agricultural environments and plant biotechnology applications. By improving enzyme performance, it should be possible to alleviate constraints on yield and quality currently imposed by kinetic properties or enzyme instability. Enzymes can be optimized faster than naturally possible by applying directed evolution, which entails mutating a target gene in vitro and screening or selecting the mutated gene products for the desired characteristics. Continuous directed evolution is a more efficient and scalable version that accomplishes the mutagenesis and selection steps simultaneously in vivo via error-prone replication of the target gene and coupling of the host cell’s growth rate to the target gene’s function. However, published continuous systems require custom plasmid assembly, and convenient multipurpose platforms are not available. We discuss two systems suitable for continuous directed evolution of enzymes, OrthoRep in Saccharomyces cerevisiae and EvolvR in Escherichia coli, and our pilot efforts to adapt each system for high-throughput plant enzyme engineering. To test our modified systems, we used the thiamin synthesis enzyme THI4, previously identified as a prime candidate for improvement. Our adapted OrthoRep system shows promise for efficient plant enzyme engineering.

Changes in periodontal tissues, tooth sensitivity and mucosal immunity when using toothpaste with hydroxyapatite, papain, thermal mud, extracts of eleutherococcus and calendula

We studied the dynamics of changes in periodontal tissues, tooth sensitivity, as well as the state of mucosal immunity when using the ASEPTA® Remineralization toothbrush (Vertex Co., St. Petersburg, Russia) in adults. It has been shown that the continuous use of ASEPTA® Remineralization toothpaste with hydroxyapatite, thermal mud, the plant enzyme papain, extracts of eleutherococcus and calendula after performing professional oral hygiene eliminates inflammation in the gums and dental hyperesthesia, ensuring good individual oral hygiene, normalization the balance of pro-inflammatory and anti-inflammatory cytokines with a shift towards a decrease in the concentration of pro-inflammatory cytokines, as well as an increase in the synthesis of secretory immunoglobulin A, which allows us to recommend this toothpaste for people with inflammatory periodontal pathology and dental hyperesthesia.

Differences in total iron content at various altitudes of Amazonian Andes soil in Ecuador

Although iron is not contained by chlorophyll, it is indispensable for plants as it plays an essential role in the biosynthesis of chlorophyll. It is a component of many important plant enzyme systems, e.g. cytochrome oxidase, which is responsible for electron transport. Therefore, examining iron content of soils, particularly ionic forms of iron (Fe2+ and Fe3+) is important for fruit growers. In this article, we disclose the total iron content determined in soils (Hyperalic Alisol soil) at three altitudes of Amazonian rainforest in Ecuador. We examine how different altitudes impact the pH and total iron content in the selected study area. We found that total iron content significantly decreases (R2=0.966) at lower altitudes. For future studies, the authors recommend that along with Fe ion content one should determine calcium, microbial biomass, and microbial activity to better understand iron mobility and dynamics of iron uptake in the area.

Plant-Mediated Enantioselective Transformation of Indan-1-One and Indan-1-ol

The main purpose of this work was to discover the way to obtain pure enantiomers of indan-1-ol. The subject of the study was the ability of the plant enzyme system to reduce the carbonyl group of indan-1-one, as well as to oxidize the hydroxyl group of racemic indan-1-ol. Locally available fruit and vegetables were selected for stereoselective biotransformation. During the reduction, mainly alcohol of the S-(+)-configuration with a high enantiomeric excess (ee = 99%) was obtained. The opposite enantiomer was obtained in bioreduction with the apple and parsley. Racemic indan-1-ol was oxidized by all catalysts. The best result was obtained for the Jerusalem artichoke: Over 50% conversion was observed after 1 h, and the enantiomeric excess of unreacted R-(–)-indan1-ol was 100%.