Alexandrium spp.: From Toxicity to Potential Biotechnological Benefits.

Many dinoflagellates of the genus Alexandrium are well known for being responsible for harmful algal blooms (HABs), producing potent toxins that cause damages to other marine organisms, aquaculture, fishery, tourism, as well as induce human intoxications and even death after consumption of contaminated shellfish or fish. In this review, we summarize potential bioprospecting associated to the genus Alexandrium, including which Alexandrium spp. produce metabolites with anticancer, antimicrobial, antiviral, as well as anti-Alzheimer applications. When available, we report their mechanisms of action and targets. We also discuss recent progress on the identification of secondary metabolites with biological properties favorable to human health and aquaculture. Altogether, this information highlights the importance of studying which culturing conditions induce the activation of enzymatic pathways responsible for the synthesis of bioactive metabolites. It also suggests considering and comparing clones collected in different locations for toxin monitoring and marine bioprospecting. This review can be of interest not only for the scientific community, but also for the entire population and industries.

De novo Transcriptome of the Non-saxitoxin Producing Alexandrium tamutum Reveals New Insights on Harmful Dinoflagellates.

Many dinoflagellates species, especially of the Alexandrium genus, produce a series of toxins with tremendous impacts on human and environmental health, and tourism economies. Alexandrium tamutum was discovered for the first time in the Gulf of Naples, and it is not known to produce saxitoxins. However, a clone of A. tamutum from the same Gulf showed copepod reproduction impairment and antiproliferative activity. In this study, the full transcriptome of the dinoflagellate A. tamutum is presented in both control and phosphate starvation conditions. RNA-seq approach was used for in silico identification of transcripts that can be involved in the synthesis of toxic compounds. Phosphate starvation was selected because it is known to induce toxin production for other Alexandrium spp. Results showed the presence of three transcripts related to saxitoxin synthesis (sxtA, sxtG and sxtU), and others potentially related to the synthesis of additional toxic compounds (e.g., 44 transcripts annotated as "polyketide synthase"). These data suggest that even if this A. tamutum clone does not produce saxitoxins, it has the potential to produce toxic metabolites, in line with the previously observed activity. These data give new insights into toxic microalgae, toxin production and their potential applications for the treatment of human pathologies.

Des-acyl ghrelin reduces alcohol intake and alcohol-induced reward in rodents.

The mechanisms contributing to alcohol use disorder (AUD) are complex and the orexigenic peptide ghrelin, which enhances alcohol reward, is implied as a crucial modulator. The major proportion of circulating ghrelin is however the non-octanoylated form of ghrelin, des-acyl ghrelin (DAG), whose role in reward processes is unknown. As recent studies show that DAG decreases food intake, we hypothesize that DAG attenuates alcohol-related responses in animal models. Acute and repeated DAG treatment dose-dependently decreased alcohol drinking in male and female rats. In these alcohol-consuming male rats, repeated DAG treatment causes higher levels of dopamine metabolites in the ventral tegmental area, an area central to reward processing. The role of DAG in reward processing is further supported as DAG prevents alcohol-induced locomotor stimulation, reward in the conditioned place preference paradigm, and dopamine release in the nucleus accumbens in male rodents. On the contrary, DAG does not alter the memory of alcohol reward or affect neurotransmission in the hippocampus, an area central to memory. Further, circulating DAG levels are positively correlated with alcohol drinking in female but not male rats. Studies were conducted in attempts to identify tentative targets of DAG, which currently are unknown. Data from these recombinant cell system revealed that DAG does not bind to either of the monoamine transporters, 5HT2A, CB1, or µ-opioid receptors. Collectively, our data show that DAG attenuates alcohol-related responses in rodents, an effect opposite to that of ghrelin, and contributes towards a deeper insight into behaviors regulated by the ghrelinergic signaling pathway.

Human metabolism of the semi-synthetic cannabinoids hexahydrocannabinol, hexahydrocannabiphorol and their acetates using hepatocytes and urine samples.

Hexahydrocannabinol (HHC), hexahydrocannabiphorol (HHCP) and their acetates, HHC-O and HHCP-O, respectively, are emerging in Europe as alternatives to tetrahydrocannabinol (THC). This study aimed to elucidate the metabolic pathways of the semi-synthetic cannabinoids HHC, HHCP, HHC-O and HHCP-O from incubation with human hepatocytes. The metabolites of HHC were also identified in authentic urine samples. HHC, HHCP, HHC-O and HHCP-O were incubated with primary human hepatocytes for 1, 3 and 5 h. Authentic urine samples from cases screened positive for cannabis in blood using ELISA but confirmed negative were analysed both non-hydrolysed and hydrolysed for HHC metabolites. Potential metabolites were identified using ultra-high performance liquid chromatography (UHPLC) coupled to a quadrupole time-of-flight mass spectrometer (QToF-MS). HHC and HHCP were primarily metabolised through monohydroxylation (monoOH), followed by oxidation to a carboxylic acid metabolite. HHC-O and HHCP-O were rapidly metabolised to HHC and HHCP, respectively. In authentic urine samples, 18 different metabolites were identified, and 99.3% of hydroxylated metabolites were glucuronidated. 11-OH-HHC, 5'OH-HHC and another metabolite with a monoOH on the side chain were the only metabolites present in all 16 urine samples. The metabolism of HHC and HHCP were similar, although the longer alkyl side chain of HHCP (heptyl) led to greater hydroxylation on the side chain than HHC (pentyl). The use of HHC and HHCP can be differentiated from the use of THC and other phytocannabinoids, but the use of the acetate analogues may not be differentiable from their non-acetate analogues.

Metabolism studies of 4'Cl-CUMYL-PINACA, 4'F-CUMYL-5F-PINACA and 4'F-CUMYL-5F-PICA using human hepatocytes and LC-QTOF-MS analysis.

4'Cl-cumyl-PINACA (SGT-157), 4'F-cumyl-5F-PINACA (4F-cumyl-5F-PINACA, SGT-65) and 4'F-cumyl-5F-PICA (4F-cumyl-5F-PICA, SGT-64) are a series of new halogenated cumyl synthetic cannabinoid receptor agonists (SCRAs). Due to rapid metabolism, monitoring and screening for SCRAs in biological matrices requires identification of their metabolites. It is an essential tool for estimating their spread and fluctuations in the global illicit market. The purpose of this study was to identify human biotransformations of 4'Cl-cumyl-PINACA, 4'F-cumyl-5F-PINACA and 4'F-cumyl-5F-PICA in vitro and characterize for the first time the metabolic pathways of halogenated cumyl SCRAs. 4'Cl-cumyl-PINACA, 4'F-cumyl-5F-PINACA and 4'F-cumyl-5F-PICA were incubated with human hepatocytes in duplicates for 0, 1, 3 and 5 h. The supernatants were analysed in data-dependent acquisition on a UHPLC-QToF-MS, and the potential metabolites were tentatively identified. A total of 11 metabolites were detected for 4'Cl-cumyl-PINACA, 21 for 4'F-cumyl-5F-PINACA and 10 for 4'F-cumyl-5F-PICA. The main biotransformations were oxidative defluorination, followed by hydroxylation with dehydrogenation, N-dealkylation, dihydrodiol formation and glucuronidation. Hydroxylations were most common at the tail moieties with higher abundancy for indole than indazole compounds. N-dealkylations were more common for fluorinated tail chain compounds than the non-fluorinated 4'Cl-cumyl-PINACA. In conclusion, many metabolites retained halogen groups at the cumyl moieties which, in various combinations, may be suitable as analytical biomarkers.

Determination of Fungi and Multi-Class Mycotoxins in Camelia Sinensis and Herbal Teas and Dietary Exposure Assessment.

In this paper, a study of fungal and multi-mycotoxin contamination in 140 Camellia sinensis and 26 herbal teas marketed in Latvia is discussed. The analysis was performed using two-dimensional liquid chromatography with time-of-flight mass spectrometry (2D-LC-TOF-MS) and MALDI-TOF-MS. In total, 87% of the tea samples tested positive for 32 fungal species belonging to 17 genera, with the total enumeration of moulds ranging between 1.00 × 101 and 9.00 × 104 CFU g-1. Moreover, 42% of the teas (n = 70) were contaminated by 1 to 16 mycotoxins, and 37% of these samples were positive for aflatoxins at concentrations ranging between 0.22 and 41.7 µg kg-1. Deoxynivalenol (DON) and its derivatives co-occurred in 63% of the tea samples, with their summary concentrations reaching 81.1 to 17,360 µg kg-1. Ochratoxin A (OTA), enniatins, and two Alternaria toxins were found in 10-37% of the teas at low concentrations. The dietary exposure assessment based on the assumption of a probable full transfer of determined mycotoxins into infusions indicated that the analysed teas are safe for consumers: the probable maximum daily exposure levels to OTA and the combined DON mycotoxins were only 0.88 to 2.05% and 2.50 to 78.9% of the tolerable daily intake levels.