Ancient Bacterial Class Alphaproteobacteria Cytochrome P450 Monooxygenases Can Be Found in Other Bacterial Species

Cytochrome P450 monooxygenases (CYPs/P450s), heme-thiolate proteins, are well-known players in the generation of chemicals valuable to humans and as a drug target against pathogens. Understanding the evolution of P450s in a bacterial population is gaining momentum. In this study, we report comprehensive analysis of P450s in the ancient group of the bacterial class Alphaproteobacteria. Genome data mining and annotation of P450s in 599 alphaproteobacterial species belonging to 164 genera revealed the presence of P450s in only 241 species belonging to 82 genera that are grouped into 143 P450 families and 214 P450 subfamilies, including 77 new P450 families. Alphaproteobacterial species have the highest average number of P450s compared to Firmicutes species and cyanobacterial species. The lowest percentage of alphaproteobacterial species P450s (2.4%) was found to be part of secondary metabolite biosynthetic gene clusters (BGCs), compared other bacterial species, indicating that during evolution large numbers of P450s became part of BGCs in other bacterial species. Our study identified that some of the P450 families found in alphaproteobacterial species were passed to other bacterial species. This is the first study to report on the identification of CYP125 P450, cholesterol and cholest-4-en-3-one hydroxylase in alphaproteobacterial species (Phenylobacterium zucineum) and to predict cholesterol side-chain oxidation capability (based on homolog proteins) by P. zucineum.     

Lifestyles Shape the Cytochrome P450 Repertoire of the Bacterial Phylum Proteobacteria

For the last six decades, cytochrome P450 monooxygenases (CYPs/P450s), heme thiolate proteins, have been under the spotlight due to their regio- and stereo-selective oxidation activities, which has led to the exploration of their applications in almost all known areas of biology. The availability of many genome sequences allows us to understand the evolution of P450s in different organisms, especially in the Bacteria domain. The phenomenon that “P450s play a key role in organisms’ adaptation vis a vis lifestyle of organisms impacts P450 content in their genome” was proposed based on studies on a handful of individual bacterial groups. To have conclusive evidence, one must analyze P450s and their role in secondary metabolism in species with diverse lifestyles but that belong to the same category. We selected species of the phylum Proteobacteria classes, Alpha, Beta, Gamma, Delta, and Epsilon, to address this research gap due to their diverse lifestyle and ancient nature. The study identified that the lifestyle of alpha-, beta-, gamma-, delta-, and epsilon-proteobacterial species profoundly affected P450 profiles in their genomes. The study determined that irrespective of the species associated with different proteobacterial classes, pathogenic species or species adapted to a simple lifestyle lost or had few P450s in their genomes. On the contrary, species with saprophytic or complex lifestyles had many P450s and secondary metabolite biosynthetic gene clusters. The study findings prove that the phenomenon mentioned above is factual, and there is no link between the number and diversity of P450s and the age of the bacteria.     

Ketogenic and Low FODMAP Diet in Therapeutic Management of a Young Autistic Patient with Epilepsy and Dysmetabolism Poorly Responsive to Therapies: Clinical Response and Effects of Intestinal Microbiota

Autism spectrum disorder (ASD) is often associated with several intestinal and/or metabolic disorders as well as neurological manifestations such as epilepsy (ASD-E). Those presenting these neuropathological conditions share common aspects in terms of gut microbiota composition. The use of microbiota intervention strategies may be an approach to consider in the management of these cases. We describe the case of a 17-year-old girl affected by ASD, reduced growth, neurological development delay, mutations in the PGM1 and EEF1A2 genes (in the absence of clinically manifested disease) and, intestinal disorders such as abdominal pain and diarrhea associated with weight loss. As she demonstrated poor responsiveness to the therapies provided, we attempted two specific dietary patterns: a ketogenic diet, followed by a low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet, with the aim of improving her neurological, metabolic, and intestinal symptoms through modulation of the gut microbiota’s composition. The ketogenic diet (KD) provided a reduction in Firmicutes, Bacteroidetes, and Proteobacteria. Although her intestinal symptoms improved, KD was poorly tolerated. On the other hand, the passage to a low FODMAPs diet produced a significant improvement in all neurological, intestinal, and metabolic symptoms and was well-tolerated. The following gut microbiota analysis showed reductions in Actinobacteria, Firmicutes, Lactobacilli, and Bifidobacteria. The alpha biodiversity was consistently increased and the Firmicutes/Bacteroidetes ratio decreased, reducing the extent of fermentative dysbiosis. Gut microbiota could be a therapeutic target to improve ASD-related symptoms. Further studies are needed to better understand the correlation between gut microbiota composition and ASD, and its possible involvement in the physiopathology of ASD.     

The Treatment Efficiency and Microbiota Analysis of Sapindus mukorossi Seed Oil on the Ligature-Induced Periodontitis Rat Model

Periodontitis is a common oral disease mainly caused by bacterial infection and inflammation of the gingiva. In the prevention or treatment of periodontitis, anti-bacterial agents are used to inhibit pathogen growth, despite increasing levels of bacterial resistance. Sapindus mukorossi Gaertn (SM) seed oil has proven anti-bacterial and anti-inflammation properties. However, the possibility of using this plant to prevent or treat periodontitis has not been reported previously. The aim of this study was to evaluate the effects of SM oil on experimental periodontitis in rats by using micro-CT and microbiota analysis. The distance between cementoenamel junction (CEJ) and alveolar bone crest (ABC) on the sagittal micro-CT slide showed that total bone loss (TBL) was significantly lower in CEJ-ABC distances between SM oil and SM oil-free groups on Day 14. Histology data also showed less alveolar bone resorption, a result consistent result with micro-CT imaging. The microbiota analyzed at phylum and class levels were compared between the SM oil and SM oil-free groups on Day 7 and Day 14. At the phylum level, Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria were the dominant bacterium. Firmicutes in box plot analysis was significantly less in the SM oil group than in the SM oil-free group on Day 7. At the class level, Bacteroidia, Gammaproteobacteria, Bacilli, Clostridia, and Erysipelotrichia were the dominant bacteria. The bacteria composition proportion of Bacilli, Clostridiay, and Erysipelotrichia could be seen in the SM oil group significantly less than in t SM oil-free group on Day 7. Overall, the present results show that topical application of SM oil can reduce bone resorption and change bacteria composition in the ligature-induced periodontitis model. According to these results, it is reasonable to suggest SM oil as a potential material for preventing oral disease.     

Biotransformation of medium-chain alkanes using recombinant P450 monooxygenase from <Emphasis Type="Italic">Alcanivorax borkumensis</Emphasis> SK2 expressed in <Emphasis Type="Italic">Escherichia coli</Emphasis>

A bioconversion system for medium-chain alkanes was constructed by using a recombinant Escherichia coli whole-cell biocatalyst expressing P450 monooxygenase genes, ferredoxin, and ferredoxin reductase cloned from Alcanivorax borkumensis as an operon. The recombinant E. coli harboring the P450 gene and two related expression component enzymes, ferredoxin and ferredoxin reductase, was constructed in a single vector pET21(a) and successfully expressed in E. coli BL21(DE3) as a soluble form, showing a molecular weight of 53 kDa on 10% SDS-PAGE. When the cell-free extract of E. coli BL21 expressing p450 monooxygenase was subjected to reduced CO difference spectral analysis, a soret band near 450 nm appeared indicating that the cloned P450 was expressed as a functionally active enzyme. The E. coli cells harboring the expressed P450 gene were able to convert n-octane and 1-decene, producing approximately 450 μg/ml of n-octanol and 290 μg/ml of 1,2-epoxydecane, respectively, at pH 7.0 and 30 °C. However, the recombinant E. coli cells were not able to convert the branched alkane, 2,6,10,14-tetramethylpentadecane (C19).     

Modulation of Gut Microbiota Combined with Upregulation of Intestinal Tight Junction Explains Anti-Inflammatory Effect of Corylin on Colitis-Associated Cancer in Mice

Inflammatory bowel disease (IBD) involves chronic inflammation, loss of epithelial integrity, and gastrointestinal microbiota dysbiosis, resulting in the development of a colon cancer known as colitis-associated colorectal cancer (CAC). In this study, we evaluated the effects of corylin in a mouse model of dextran sodium sulfate (DSS)-induced colitis. The results showed corylin could improved the survival rate and colon length, maintained body weight, and ameliorated the inflammatory response in the colon. Then, we further identified the possible antitumor effects after 30-day treatment of corylin on an azoxymethane (AOM)/DSS-induced CAC mouse model. Biomarkers associated with inflammation, the colon tissue barrier, macrophage polarization (CD11c, CCR7, CD163, and CD206), and microbiota dysbiosis were monitored in the AOM/DSS group versus corylin groups. Corylin downregulated pro-inflammatory cytokines (TNF-α, IFN-γ, IL-1β, and IL-6) mRNA expression and inflammatory signaling-associated markers (TLR4, MyD88, AP-1, CD11b, and F4/80). In addition, a colon barrier experiment revealed that epithelial cell proliferation of the mucus layer (Lgr5, Cyclin D1, and Olfm4) was downregulated and tight junction proteins (claudin-1 and ZO-1) were upregulated. Furthermore, the Firmicutes/Bacteroidetes ratio changed with corylin intervention, and the microbial diversity and community richness of the AOM/DSS mice were improved by corylin. The comparative analysis of gut microbiota revealed that Bacteroidetes, Patescibacteria, Candidatus Saccharimonas, Erysipelatoclostridium, and Enterorhabdus were significantly increased but Firmicutes, Turicibacter, Romboutsia, and Blautia decreased after corylin treatment. Altogether, corylin administration showed cancer-ameliorating effects by reducing the risk of colitis-associated colon cancer via regulation of inflammation, carcinogenesis, and compositional change of gut microbiota. Therefore, corylin could be a novel, potential health-protective, natural agent against CAC.     

Leaf Bacteriome in Sugar Beet Shows Differential Response against Beet curly top virus during Resistant and Susceptible Interactions

Beet curly top virus (BCTV) significantly reduces sugar beet yield in semi-arid production areas. Genetic resistance to BCTV is limited; therefore, identification of additional resistance-associated factors is highly desired. Using 16S rRNA sequencing and BCTV resistant (R) genotypes (KDH13, KDH4-9) along with a susceptible (S) genotype (KDH19-17), we investigated leaf bacteriome changes during BCTV post inoculation (pi). At day 6 (~6-week-old plants), Cyanobacteria were predominant (~90%); whereas, at week 4 (~10-week-old plants) Firmicutes (11–66%), Bacteroidetes (17–26%), and Verrucomicrobia (12–29%) were predominant phyla and genotype dependent. Both Bacteroidetes and Verrucomicrobia, increased post infection only in the R lines. The bacterial genera Brevibacillus increased at 6 dpi, and Akkermansia and Bacteroides at 4 wkpi in the R lines. Linear discriminant analysis effect size (LEfSe) identified potential biomarkers in the R vs. S lines. Functional profiling revealed bacterial enrichment associated with the TCA cycle, polyisoprenoid, and L-methionine biosynthesis pathways only in KDH4-9 at 6 dpi. At 4 wkpi, bacteria associated with tryptophan and palmitate biosynthesis in the R lines, and uridine monophosphate, phosphatidyl glycerol, and phospholipid biosynthesis in the S line, were enriched. Future characterization of bacterial genera with antiviral properties will help establish their use as biocontrol agents/biomarkers against BCTV.     

Structural domains of P450-containing monooxygenase systems

All known P450-containing monooxygenase systems share commonstructural and functional domain architecture. Apart from P450itself, these systems can comprise several fundamentally differentprotein components or domains, all of which are shared by othermulticomponent/multidomain enzyme systems with various functions:FAD flavoprotein or domain, FMN domain, Fe₂S₂ ferredoxin, Fe₃S₄ferredoxin, and cytochrome b₅. Either FMN domain, ferredoxinsor cytochrome bs serve as the electron transport intermediatebetween the FAD domain and P450. The molecular evolution ofboth P450-containing systems and of each particular componentdoes not follow phylogeny in general. Gene fusion and horizontalgene transfer events can lead to the appearance of novel redoxchains in the same manner that artificial chimeric proteinscan be constructed by humans. Recent studies using genetic andprotein engineering techniques to investigate the separate domainsand their interaction are described.     

Cloning,Expression and Purification of Cindoxin,an Unusual Fmn‐Containing Cytochrome P450 Redox Partner

Cytochromes P450 (P450s) belong to a superfamily of haemoproteins that catalyse a remarkable variety of oxidative transformations. P450 catalysis generally requires that cognate redox proteins transfer electrons, derived ultimately from NAD(P)H, to the P450 for oxygen activation. P450_cin (CYP176A1) is a bacterial P450 that is postulated to allow Citrobacter braakii to live on cineole as its sole carbon source by initiating cineole biodegradation. Here we report the cloning, expression, purification and characterisation of one of its postulated redox partners, cindoxin (Cdx), which has strong similarity to the FMN domain of cytochrome P450 reductase. Cindoxin reductase (CdR), which displays strong similarity to NADPH‐dependent ferredoxin reductases, was unable to be expressed in a functional form. Mass spectrometric and HPLC analyses confirmed that the flavin cofactor of cindoxin was FMN. Redox potentiometric titrations were performed with cindoxin within the range 6<pH<8; this enabled the quinone/semiquinone (E₁) and semiquinone/hydroquinone (E₂) redox potentials to be determined. Our results show that cindoxin might be somewhat different to other flavodoxins that interact with P450s, in which generally only one couple is important. Both redox states of cindoxin could be catalytically relevant. A catalytically active system was reconstituted in vitro with E. coli flavodoxin reductase (Fpr) acting as the terminal redox partner in the absence of CdR. Our results show that Cdx and Fpr support regio‐ and stereoselective P450_cin‐catalysed cineole oxidation to (1R)‐6β‐hydroxycineole with turnover rates up to 1500 min^?1. This system is tightly coupled with 80 % of NADPH reducing equivalents funnelled into substrate oxidation.     

Diverse Evolution in 111 Plant Genomes Reveals Purifying and Dosage Balancing Selection Models for F-Box Genes

The F-box proteins function as substrate receptors to determine the specificity of Skp1-Cul1-F-box ubiquitin ligases. Genomic studies revealed large and diverse sizes of the F-box gene superfamily across plant species. Our previous studies suggested that the plant F-box gene superfamily is under genomic drift evolution promoted by epigenomic programming. However, how the size of the superfamily drifts across plant genomes is currently unknown. Through a large-scale genomic and phylogenetic comparison of the F-box gene superfamily covering 110 green plants and one red algal species, I discovered four distinct groups of plant F-box genes with diverse evolutionary processes. While the members in Clusters 1 and 2 are species/lineage-specific, those in Clusters 3 and 4 are present in over 46 plant genomes. Statistical modeling suggests that F-box genes from the former two groups are skewed toward fewer species and more paralogs compared to those of the latter two groups whose presence frequency and sizes in plant genomes follow a random statistical model. The enrichment of known Arabidopsis F-box genes in Clusters 3 and 4, along with comprehensive biochemical evidence showing that Arabidopsis members in Cluster 4 interact with the Arabidopsis Skp1-like 1 (ASK1), demonstrates over-representation of active F-box genes in these two groups. Collectively, I propose purifying and dosage balancing selection models to explain the lineage/species-specific duplications and expansions of F-box genes in plant genomes. The purifying selection model suggests that most, if not all, lineage/species-specific F-box genes are detrimental and are thus kept at low frequencies in plant genomes.     

Genome-Wide Identification and Analyses of Drought/Salt-Responsive Cytochrome P450 Genes in Medicago truncatula

Cytochrome P450 monooxygenases (P450s) catalyze a great number of biochemical reactions and play vital roles in plant growth, development and secondary metabolism. As yet, the genome-scale investigation on P450s is still lacking in the model legume Medicago truncatula. In particular, whether and how many MtP450s are involved in drought and salt stresses for Medicago growth, development and yield remain unclear. In this study, a total of 346 MtP450 genes were identified and classified into 10 clans containing 48 families. Among them, sixty-one MtP450 genes pairs are tandem duplication events and 10 MtP450 genes are segmental duplication events. MtP450 genes within one family exhibit high conservation and specificity in intron–exon structure. Meanwhile, many Mt450 genes displayed tissue-specific expression pattern in various tissues. Specifically, the expression pattern of 204 Mt450 genes under drought/NaCl treatments were analyzed by using the weighted correlation network analysis (WGCNA). Among them, eight genes (CYP72A59v1, CYP74B4, CYP71AU56, CYP81E9, CYP71A31, CYP704G6, CYP76Y14, and CYP78A126), and six genes (CYP83D3, CYP76F70, CYP72A66, CYP76E1, CYP74C12, and CYP94A52) were found to be hub genes under drought/NaCl treatments, respectively. The expression levels of these selected hub genes could be induced, respectively, by drought/NaCl treatments, as validated by qPCR analyses, and most of these genes are involved in the secondary metabolism and fatty acid pathways. The genome-wide identification and co-expression analyses of M. truncatula P450 superfamily genes established a gene atlas for a deep and systematic investigation of P450 genes in M. truncatula, and the selected drought-/salt-responsive genes could be utilized for further functional characterization and molecular breeding for resistance in legume crops.     

Effects of Probiotic Supplementation during Pregnancy on the Future Maternal Risk of Metabolic Syndrome

Probiotics are live microorganisms that induce health benefits in the host. Taking probiotics is generally safe and well tolerated by pregnant women and their children. Consumption of probiotics can result in both prophylactic and therapeutic effects. In healthy adult humans, the gut microbiome is stable at the level of the dominant taxa: Bacteroidetes, Firmicutes and Actinobacteria, and has a higher presence of Verrucomicrobia. During pregnancy, an increase in the number of Proteobacteria and Actinobacteria phyla and a decrease in the beneficial species Roseburia intestinalis and Faecalibacterium prausnitzii are observed. Pregnancy is a “window” to the mother’s future health. The aim of this paper is to review studies assessing the potentially beneficial effects of probiotics in preventing the development of diseases that appear during pregnancy, which are currently considered as risk factors for the development of metabolic syndrome, and consequently, reducing the risk of developing maternal metabolic syndrome in the future. The use of probiotics in gestational diabetes mellitus, preeclampsia and excessive gestational weight gain is reviewed. Probiotics are a relatively new intervention that can prevent the development of these disorders during pregnancy, and thus, would reduce the risk of metabolic syndrome resulting from these disorders in the mother’s future.     

Molecular Cloning and Expression of CYP9A61: A Chlorpyrifos-Ethyl and Lambda-Cyhalothrin-Inducible Cytochrome P450 cDNA from Cydia pomonella

Cytochrome P450 monooxygenases (CYPs or P450s) play paramount roles in detoxification of insecticides in a number of insect pests. However, little is known about the roles of P450s and their responses to insecticide exposure in the codling moth Cydia pomonella (L.), an economically important fruit pest. Here we report the characterization and expression analysis of the first P450 gene, designated as CYP9A61, from this pest. The full-length cDNA sequence of CYP9A61 is 2071 bp long and its open reading frame (ORF) encodes 538 amino acids. Sequence analysis shows that CYP9A61 shares 51%–60% identity with other known CYP9s and contains the highly conserved substrate recognition site SRS1, SRS4 and SRS5. Quantitative real-time PCR showed that CYP9A61 were 67-fold higher in the fifth instar larvae than in the first instar, and more abundant in the silk gland and fat body than other tissues. Exposure of the 3rd instar larvae to 12.5 mg L⁻¹ of chlorpyrifos-ethyl for 60 h and 0.19 mg L⁻¹ of lambda-cyhalothrin for 36 h resulted in 2.20-and 3.47-fold induction of CYP9A61, respectively. Exposure of the 3rd instar larvae to these two insecticides also significantly enhanced the total P450 activity. The results suggested that CYP9A61 is an insecticide-detoxifying P450.     

Insights into the Host Specificity of a New Oomycete Root Pathogen,Pythium brassicum P1: Whole Genome Sequencing and Comparative Analysis Reveals Contracted Regulation of Metabolism,Protein Families,and Distinct Pathogenicity Repertoire

Pythium brassicum P1 Stanghellini, Mohammadi, Förster, and Adaskaveg is an oomycete root pathogen that has recently been characterized. It only attacks plant species belonging to Brassicaceae family, causing root necrosis, stunting, and yield loss. Since P. brassicum P1 is limited in its host range, this prompted us to sequence its whole genome and compare it to those of broad host range Pythium spp. such as P. aphanidermatum and P. ultimum var. ultimum. A genomic DNA library was constructed with a total of 374 million reads. The sequencing data were assembled using SOAPdenovo2, yielding a total genome size of 50.3 Mb contained in 5434 scaffolds, N50 of 30.2 Kb, 61.2% G+C content, and 13,232 putative protein-coding genes. Pythium brassicum P1 had 175 species-specific gene families, which is slightly below the normal average. Like P. ultimum, P. brassicum P1 genome did not encode any classical RxLR effectors or cutinases, suggesting a significant difference in virulence mechanisms compared to other oomycetes. Pythium brassicum P1 had a much smaller proportions of the YxSL sequence motif in both secreted and non-secreted proteins, relative to other Pythium species. Similarly, P. brassicum P1 had the fewest Crinkler (CRN) effectors of all the Pythium species. There were 633 proteins predicted to be secreted in the P. brassicum P1 genome, which is, again, slightly below average among Pythium genomes. Pythium brassicum P1 had only one cadherin gene with calcium ion-binding LDRE and DxND motifs, compared to Pythium ultimum having four copies. Pythium brassicum P1 had a reduced number of proteins falling under carbohydrate binding module and hydrolytic enzymes. Pythium brassicum P1 had a reduced complement of cellulase and pectinase genes in contrast to P. ultimum and was deficient in xylan degrading enzymes. The contraction in ABC transporter families in P. brassicum P1 is suggested to be the result of a lack of diversity in nutrient uptake and therefore host range.     

Transposable Prophages in Leptospira: An Ancient,Now Diverse,Group Predominant in Causative Agents of Weil’s Disease

The virome associated with the corkscrew shaped bacterium Leptospira, responsible for Weil’s disease, is scarcely known, and genetic tools available for these bacteria remain limited. To reduce these two issues, potential transposable prophages were searched in Leptospiraceae genomes. The 236 predicted transposable prophages were particularly abundant in the most pathogenic leptospiral clade, being potentially involved in the acquisition of virulent traits. According to genomic similarities and phylogenies, these prophages are distantly related to known transposable phages and are organized into six groups, one of them encompassing prophages with unusual TA-TA ends. Interestingly, structural and transposition proteins reconstruct different relationships between groups, suggesting ancestral recombinations. Based on the baseplate phylogeny, two large clades emerge, with specific gene-contents and high sequence divergence reflecting their ancient origin. Despite their high divergence, the size and overall genomic organization of all prophages are very conserved, a testimony to the highly constrained nature of their genomes. Finally, similarities between these prophages and the three known non-transposable phages infecting L. biflexa, suggest gene transfer between different Caudovirales inside their leptospiral host, and the possibility to use some of the transposable prophages in that model strain.     

Microbial community dynamics and electron transfer of a biocathode in microbial fuel cells

Microbial community dynamics and its electron transfer process within a biocathode in a microbial fuel cell (MFC) were investigated in this study. The MFC was operated steadily over 400 days, and the power density reached 1.92 and 10.27 W/m³ based on the reduction of nitrate and oxygen, respectively. The six major groups of the clones that were categorized among the 26 clone types were Proteobacteria, Bacteroidetes, Actinobacteria, Planctomycetes, Firmicutes and uncultured bacteria. Microbial community dynamics showed that Betaproteobacteria was replaced by Gammaproteobacteria as the most abundant division among all the clone types with a percentage of 48.86% in the cathode compartment, followed by 20.45% of uncultured bacteria, 17.05% of Bacteroidetes, and others. Distinct oxidation and reduction peaks could be observed in the profiles of cathodic effluent during the cyclic and differential pulse voltammetry tests. It confirmed that nitrate and oxygen reduction in the cathode compartment could be significantly enhanced by the presence of microbes, which are able to excrete metabolites to assist the electron transfer process either in the anode or in the cathode compartment.     

Benzo[a]pyrene—Environmental Occurrence,Human Exposure,and Mechanisms of Toxicity

Benzo[a]pyrene (B[a]P) is the main representative of polycyclic aromatic hydrocarbons (PAHs), and has been repeatedly found in the air, surface water, soil, and sediments. It is present in cigarette smoke as well as in food products, especially when smoked and grilled. Human exposure to B[a]P is therefore common. Research shows growing evidence concerning toxic effects induced by this substance. This xenobiotic is metabolized by cytochrome P450 (CYP P450) to carcinogenic metabolite: 7β,8α-dihydroxy-9α,10α-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE), which creates DNA adducts, causing mutations and malignant transformations. Moreover, B[a]P is epigenotoxic, neurotoxic, and teratogenic, and exhibits pro-oxidative potential and causes impairment of animals’ fertility. CYP P450 is strongly involved in B[a]P metabolism, and it is simultaneously expressed as a result of the association of B[a]P with aromatic hydrocarbon receptor (AhR), playing an essential role in the cancerogenic potential of various xenobiotics. In turn, polymorphism of CYP P450 genes determines the sensitivity of the organism to B[a]P. It was also observed that B[a]P facilitates the multiplication of viruses, which may be an additional problem with the widespread COVID-19 pandemic. Based on publications mainly from 2017 to 2022, this paper presents the occurrence of B[a]P in various environmental compartments and human surroundings, shows the exposure of humans to this substance, and describes the mechanisms of its toxicity.     

Horizontal Transfer of LTR Retrotransposons Contributes to the Genome Diversity of Vitis

While horizontally transferred transposable elements (TEs) have been reported in several groups of plants, their importance for genome evolution remains poorly understood. To understand how horizontally transferred TEs contribute to plant genome evolution, we investigated the composition and activity of horizontally transferred TEs in the genomes of four Vitis species. A total of 35 horizontal transfer (HT) events were identified between the four Vitis species and 21 other plant species belonging to 14 different families. We determined the donor and recipient species for 28 of these HTs, with the Vitis species being recipients of 15 of them. As a result of HTs, 8–10 LTR retrotransposon clusters were newly formed in the genomes of the four Vitis species. The activities of the horizontally acquired LTR retrotransposons differed among Vitis species, showing that the consequences of HTs vary during the diversification of the recipient lineage. Our study provides the first evidence that the HT of TEs contributes to the diversification of plant genomes by generating additional TE subfamilies and causing their differential proliferation in host genomes.