Analysis Of Gene Clusters Research Articles

Whole genome sequence of Lactiplantibacillus plantarum MC5 and comparative analysis of eps gene clusters.

Probiotic Lactiplantibacillus plantarum MC5 produces large amounts of exopolysaccharides (EPS), and its use as a compound fermentor can greatly improve the quality of fermented milk. To gain insight into the genomic characteristics of probiotic MC5 and reveal the relationship between its EPS biosynthetic phenotype and genotype, we analyzed the carbohydrate metabolic capacity, nucleotide sugar formation pathways, and EPS biosynthesis-related gene clusters of strain MC5 based on its whole genome sequence. Finally, we performed validation tests on the monosaccharides and disaccharides that strain MC5 may metabolize. Genomic analysis showed that MC5 has seven nucleotide sugar biosynthesis pathways and 11 sugar-specific phosphate transport systems, suggesting that the strain can metabolize mannose, fructose, sucrose, cellobiose, glucose, lactose, and galactose. Validation results showed that strain MC5 can metabolize these seven sugars and produce significant amounts of EPS (> 250 mg/L). In addition, strain MC5 possesses two typical eps biosynthesis gene clusters, which include the conserved genes epsABCDE, wzx, and wzy, six key genes for polysaccharide biosynthesis, and one MC5-specific epsG gene. These insights into the mechanism of EPS-MC5 biosynthesis can be used to promote the production of EPS through genetic engineering.

Analysis Of Differentially Expressed Genes By RNA-Sequencing In 38 Cases of Rasmussen Encephalitis: New Insights on Non-Inflammatory Pathways (P12-9.002)

<h3>Objective:</h3> To analyze aberrant gene expression pathways involved in the pathophysiology of Rasmussen Encephalitis (RE) in a large cohort of brain specimens from affected children. <h3>Background:</h3> RE is a rare cause of pharmacoresistant epilepsy, characterized by progressive hemispheric inflammation resulting in seizures and, if left untreated, hemiplegia, hemianopia and cognitive decline. Data on gene expression in this condition are lacking. <h3>Design/Methods:</h3> We conducted RNA-sequencing of flash-frozen resected epileptogenic tissue from 38 children with RE. Control brain tissue included 10 brain specimens from perilesional resected areas in different patients with focal cortical dysplasia. RNA-sequencing was performed using standard protocol on Illumina HiSeq 2x150bp sequencing, single index platform with polyA selection library prep. After extraction of normalized gene hit counts, we utilized the <i>DESeq2</i> package with R version 4.2.1. The Wald test was used to generate p-values and log2 fold changes. Genes with an adjusted p-value &lt; 0.05 were called as differentially expressed genes (DEG) for each comparison. Gene enrichment analysis was then performed with the Reactome platform. <h3>Results:</h3> We identified 6184 upregulated and 3789 downregulated genes in RE vs. controls. Functional gene clustering analysis showed overrepresentation of several pathways involved in neuroinflammation including interferon alpha/beta (p=7.77E-11) and gamma (p=1.17E-12) signaling, IL-4/IL-13 (p=1.15E-2), IL-10 (p=2.18E-2) signaling, class I MHC-mediated antigen processing (p=4.22E-5), and non-inflammatory pathways such as nonsense-mediated RNA decay (p=2.04E-3), translation elongation cycle (p=5.42E-4). We observed downregulation of multiple neuronal pathways: neurotransmitter receptors and postsynaptic signal transmission (p=3.79E-7), activation of NMDA receptors (p=1.72E-5), GABA receptor activation (p=3.19E-2), glutamate binding (p=2.1E-2), presynaptic depolarization and Ca channel opening (p=1.49E-2). Extra-neuronal downregulated genes included: transcriptional regulation of MECP2 (p=4.49E-4), L1CAM interactions (p=1.51E-3), signaling by NTRKs (p=3.93E-2), calmodulin pathway (p=2.05E-1). <h3>Conclusions:</h3> With this study, we contribute to expanding the knowledge of pathophysiological inflammatory and non-inflammatory processes involved in Rasmussen’s encephalitis. <b>Disclosure:</b> Dr. Bartolini has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for American Academy of Neurology. The institution of Dr. Chan has received research support from TSC Alliance. Ms. Lob has nothing to disclose. Ms. Wu has nothing to disclose. Dr. Uzun has nothing to disclose. Dr. Oluigbo has nothing to disclose. The institution of Dr. Gaillard has received research support from all federal or foundation grants, NINDS, NIDCD, NICHD, NSF ,PERF. Dr. Chang has nothing to disclose. Gary W. Mathern has nothing to disclose. The institution of Dr. Liu has received research support from NIH/NINDS.

Identification immune response genes in psoriasis after treatment with secukinumab

BackgroundSecukinumab is a fully human IgG1κ MoAb that selectively binds to IL-17A with high affinity, and it has been proven effective for the treatment of psoriasis. However, the immune response pathways and mechanisms during the treatment are still masked. Therefore, the current study was designed to investigate the potential immune response genes via bioinformatics approaches.MethodsGene expression data of severe plaque-type psoriasis was retrieved from the GEO database. Quantification of immune infiltration by ssGSEA and identification of differentially infiltrated immune cells were conducted to validate the treatment effect of secukinumab. After data processing, differentially expressed genes were identified between the treatment and untreated group. TC-seq was employed to analyze the trend of gene expression and clustering analysis. IL-17 therapeutic immune response genes were selected by taking the intersection of the genes inside the key cluster set and the MAD3-PSO geneset. Based on these therapeutic response genes, protein–protein interaction networks were built for key hub gene selection. These hub genes would work as potential immune response genes, and be validated via an external dataset.ResultsEnrichment scores calculated by ssGSEA illustrated that the immune infiltration level of T cells had a strong difference before and after medication, which validated the treatment effect of Secukinumab. 1525 genes that have significantly different expression patterns before and after treatment were extracted for further analysis, and the enrichment result shows that these genes have the function related to epidermal development, differentiation, and keratinocytes differentiation. After overlapping candidate genes with MAD3-PSO gene set, 695 genes were defined as anti-IL7A treatment immune response genes, which were mainly enriched in receptor signaling and IL-17 signaling pathways. Hub gene were pinpointed from the PPI network constructed by anti-IL7A treatment immune response genes, their expression pattern fits TC-seq gene expression pattern.ConclusionOur study revealed the potential anti-IL7A treatment immune response genes, and the central hub genes, which may act critical roles in Secukinumab, induced immune response. This would open up a novel and effective avenue for the treatment of psoriasis.

Mechanism of myocardial fibrosis regulation by IGF-1R in atrial fibrillation through the PI3K/Akt/FoxO3a pathway.

Atrial structural remodeling takes on a critical significance to the occurrence and maintenance of atrial fibrillation (AF). As revealed by recent data, insulin-like growth factor-1 receptor (IGF-1R) plays a certain role in tissue fibrosis. In this study, the mechanism of IGF-1R in atrial structural remodeling was examined based on in vivo and in vitro experiments. First, cluster analysis of AF hub genes was conducted, and then the molecular mechanism was proposed by which IGF-1R regulates myocardial fibrosis via the PI3K/Akt/FoxO3a pathway. Subsequently, the mentioned mechanism was verified in human cardiac fibroblasts (HCFs) and rats transduced with IGF-1 overexpression type 9 adeno-associated viruses. The results indicated that IGF-1R activation up-regulated collagen Ⅰ protein expression and Akt phosphorylation in HCFs and rat atrium. The administration of LY294002 reversed the above phenomenon, improved the shortening of atrial effective refractory period, and reduced the increased incidence of AF and atrial fibrosis in rats. The transfection of FoxO3a siRNA reduced the anti-fibrotic effect of LY294002 in HCFs. The above data revealed that activation of IGF-1R takes on a vital significance to atrial structural remodeling by facilitating myocardial fibrosis and expediting the occurrence and maintenance of AF through the regulation of the PI3K/Akt/FoxO3a signaling pathway.

Inulin increases the EPS biosynthesis of Lactobacillus delbrueckii ssp. bulgaricus LDB-C1.

Its eps gene cluster, the antioxidant activity and monosaccharide composition of exopolysaccharides, the expression levels of related genes at different fermentations were analyzed for clarifying the exopolysaccharide biosynthesis mechanism of Lactobacillus delbrueckii subsp. bulgaricus LDB-C1. The comparison analysis of eps gene clusters indicated that the gene clusters present diversity and strain specificity. The crude exopolysaccharides from LDB-C1 exhibited a good antioxidant activity. Compared with glucose, fructose, galactose, and fructooligosaccharide, inulin significantly improved the exopolysaccharide biosynthesis. The structures of EPSs were significantly different under different carbohydrate fermentation conditions. Inulin obviously increased the expressions of most EPS biosynthesis related genes at fermentation 4h. Inulin accelerated the beginning of the exopolysaccharide production in LDB-C1, and the enzymes promoted by inulin was beneficial for the accumulation of exopolysaccharide at the whole fermentation process.

Comprehensive analysis of biosynthetic gene clusters in bacteria and discovery of Tumebacillus as a potential producer of natural products.

Limited microbial genera such as Streptomyces have served as sources of natural products (NPs), whereas most others have been less investigated. The vast accumulation of genomic data available in the NCBI database enables us to bioinformatically estimate the ability of other microbial groups to produce NPs. We analyzed 21,052 complete bacterial genome sequences using antiSMASH and compared the average numbers of biosynthetic gene clusters (BGCs) related to polyketides, non-ribosomal peptides, and/or terpenes biosynthesis at the genus level. Our bioinformatic analyses showed that Tumebacillus has 5-15 BGCs and is a promising NP producer. We searched for NPs from the culture broth of Tumebacillus permanentifrigoris JCM 14557T and found two novel compounds (tumebacin with anti-Bacillus activity and tumepyrazine) and identified two known compounds. Our results highlight the diversity of sources of NPs awaiting discovery.

New insights into the neuroprotective and beta-secretase1 inhibitor profiles of tirandamycin B isolated from a newly found Streptomyces composti sp. nov.

Tirandamycin (TAM B) is a tetramic acid antibiotic discovered to be active on a screen designed to find compounds with neuroprotective activity. The producing strain, SBST2-5T, is an actinobacterium that was isolated from wastewater treatment bio–sludge compost collected from Suphanburi province, Thailand. Taxonomic characterization based on a polyphasic approach indicates that strain SBST2-5T is a member of the genus Streptomyces and shows low average nucleotide identity (ANI) (81.7%), average amino-acid identity (AAI) (78.5%), and digital DNA-DNA hybridization (dDDH) (25.9%) values to its closest relative, Streptomyces thermoviolaceus NBRC 13905T, values that are significantly below the suggested cut-off values for the species delineation, indicating that strain SBST2-5T could be considered to represent a novel species of the genus Streptomyces. The analysis of secondary metabolites biosynthetic gene clusters (smBGCs) in its genome and chemical investigation led to the isolation of TAM B. Interestingly, TAM B at 20 µg/mL displayed a suppressive effect on beta-secretase 1 (BACE1) with 68.69 ± 8.84% inhibition. Molecular docking simulation reveals the interaction mechanism between TAM B and BACE1 that TAM B was buried in the pocket of BACE-1 by interacting with amino acids Thr231, Asp 228, Gln73, Lys 107 via hydrogen bond and Leu30, Tyr71, Phe108, Ile118 via hydrophobic interaction, indicating that TAM B represents a potential active BACE1 inhibitor. Moreover, TAM B can protect the neuron cells significantly (% neuron viability = 83.10 ± 9.83% and 112.72 ± 6.83%) from oxidative stress induced by serum deprivation and Aβ1–42 administration models at 1 ng/mL, respectively, without neurotoxicity on murine P19-derived neuron cells nor cytotoxicity against Vero cells. This study was reportedly the first study to show the neuroprotective and BACE1 inhibitory activities of TAM B.

Gene clustering and co-expression analysis for the identification of putative transcription factors associated with the genes of secondary metabolic pathways in Plantago ovata Forsk. and its wild allies

Gene clustering and co-expression analysis for the identification of putative transcription factors associated with the genes of secondary metabolic pathways in Plantago ovata Forsk. and its wild allies

Progression-associated molecular changes in basal/squamous and sarcomatoid bladder carcinogenesis.

The aggressive basal/squamous (Ba/Sq) bladder cancer (BLCA) subtype is often diagnosed at the muscle-invasive stage and can progress to the sarcomatoid variant. Identification of molecular changes occurring during progression from non-muscle-invasive BLCA (NMIBC) to Ba/Sq muscle-invasive BLCA (MIBC) is thus challenging in human disease. We used the N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) mouse model of Ba/Sq MIBC to study longitudinally the molecular changes leading to the Ba/Sq phenotype and to the sarcomatoid variant using IHC and microdissection followed by RNA-seq at all stages of progression. A shift to the Ba/Sq phenotype started in early progression stages. Pathway analysis of gene clusters with coordinated expression changes revealed Shh signaling loss and a shift from fatty acid metabolism to glycolysis. An upregulated cluster, appearing early in carcinogenesis, showed relevance to human disease, identifying NMIBC patients at risk of progression. Similar to the human counterpart, sarcomatoid BBN tumors displayed a Ba/Sq phenotype and epithelial-mesenchymal transition (EMT) features. An EGFR/FGFR1 signaling switch occurred with sarcomatoid dedifferentiation and correlated with EMT. BLCA cell lines with high EMT were the most sensitive to FGFR1 knockout and resistant to EGFR knockout. Taken together, these findings provide insights into the underlying biology of Ba/Sq BLCA progression and sarcomatoid dedifferentiation with potential clinical implications. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Identification of angiogenesis-related subtypes, the development of prognostic models, and the landscape of tumor microenvironment infiltration in colorectal cancer.

Background: Angiogenesis is one of the most prominent markers of cancer progression and contributes to tumor metastasis and prognosis. Anti-angiogenic drugs have proven effective in treating metastatic colorectal cancer. However, there is some uncertainty regarding the potential role of angiogenesis-related genes in the tumor microenvironment. Methods: We analyzed 1,214 colorectal cancer samples to identify alterations in angiogenesis-related genes (ARGs), and then correlated angiogenesis with clinical features, prognosis, and TME. The ARGs expression profiles in colorectal cancer were analyzed using three computational methods (CIBERSORT, ssGSEA, and MCPcounter) and provided a systematic immune landscape. Patients with CRC were classified into two subtypes based on consensus clustering analysis of angiogenesis-related genes. The revealed differentially expressed genes between the two subtypes were used to create and validate ARGscore prognostic models. In addition, we collected eight colorectal cancer patient specimens and performed RT-qPCR to validate the signature gene expression. Results: We assessed the expression patterns of ARGs in colorectal cancer. We identified two molecular subtypes and confirmed that the expression of ARGs was associated with prognosis and TME characteristics. Based on differentially expressed genes between subtypes, we constructed ARGscore and evaluated their predictive power for the survival of colorectal cancer patients. We also developed an accurate nomogram to make the ARGscore more clinically useful. In addition, ARGscore was significantly correlated with microsatellite instability, cancer stem cells, and chemotherapeutic drug sensitivity. Patients with ARGscore-low characterized by immune activation and microsatellite instability high had a better prognosis. Conclusion: ARGs expression influenced the prognosis, clinicopathological features, and tumor stromal immune microenvironment in colorectal cancer. We developed a new risk model, ARGscore, for the treatment and prognosis of CRC patients and validated its promising predictive power. These findings will enable us to understand colorectal cancer better, assess prognoses, and develop more effective treatment options.

Bioinformatics investigation on blood-based gene expressions of Alzheimer's disease revealed ORAI2 gene biomarker susceptibility: An explainable artificial intelligence-based approach

The progressive, chronic nature of Alzheimer's disease (AD), a form of dementia, defaces the adulthood of elderly individuals. The pathogenesis of the condition is primarily unascertained, turning the treatment efficacy more arduous. Therefore, understanding the genetic etiology of AD is essential to identifying targeted therapeutics. This study aimed to use machine-learning techniques of expressed genes in patients with AD to identify potential biomarkers that can be used for future therapy. The dataset is accessed from the Gene Expression Omnibus (GEO) database (Accession Number: GSE36980). The subgroups (AD blood samples from frontal, hippocampal, and temporal regions) are individually investigated against non-AD models. Prioritized gene cluster analyses are conducted with the STRING database. The candidate gene biomarkers were trained with various supervised machine-learning (ML) classification algorithms. The interpretation of the model prediction is perpetrated with explainable artificial intelligence (AI) techniques. This experiment revealed 34, 60, and 28 genes as target biomarkers of AD mapped from the frontal, hippocampal, and temporal regions. It is identified ORAI2 as a shared biomarker in all three areas strongly associated with AD's progression. The pathway analysis showed that STIM1 and TRPC3 are strongly associated with ORAI2. We found three hub genes, TPI1, STIM1, and TRPC3, in the network of the ORAI2 gene that might be involved in the molecular pathogenesis of AD. Naive Bayes classified the samples of different groups by fivefold cross-validation with 100% accuracy. AI and ML are promising tools in identifying disease-associated genes that will advance the field of targeted therapeutics against genetic diseases.

Stictamycin, an Aromatic Polyketide Antibiotic Isolated from a New Zealand Lichen-Sourced Streptomyces Species.

Here we describe the isolation and characterization of stictamycin, a new aromatic polyketide with activity against Staphylococcus aureus. Stictamycin was identified following metabolic profiling and bioactivity guided fractionation of organic extracts from Streptomyces sp. 438-3, an isolate from the New Zealand lichen Sticta felix. Comprehensive 1D and 2D NMR analyses were performed to determine the planar structure of stictamycin and relative configurations of stereo centers, with subsequent comparison of experimental and theoretical ECD spectra allowing elucidation of the absolute configuration. Whole-genome sequencing and biosynthetic gene cluster (BGC) analysis revealed that the Streptomyces sp. 438-3 strain contains an atypical type II polyketide (T2PKS) BGC capable of assembling polycyclic-aromatic ring skeletons. Cloning and knockout studies of this T2PKS BGC were used to confirm that it is responsible for the biosynthesis of stictamycin and elucidate a plausible biosynthetic scheme.

Genome Sequencing of Streptomyces griseus SCSIO PteL053, the Producer of 2,2′-Bipyridine and Actinomycin Analogs, and Associated Biosynthetic Gene Cluster Analysis

Marine symbiotic actinomycetes play a key role in drug development and their ecological niches can influence a variety of natural product biosynthesis, providing potential defensive benefits. In this study, we report the whole-genome sequence analysis of marine gastropod mollusk Planaxis sp.-associated Streptomyces griseus SCSIO PteL053, which harbors 28 putative biosynthetic gene clusters (BGCs). Among them, two BGCs encoded by a hybrid non-ribosomal peptide (NRPS)/polyketide (PKS) synthetase and non-ribosomal peptide synthetase (NRPS) are responsible for the synthesis of the known therapeutic metabolites 2,2′-bipyridine and actinomycin analogs, respectively. Detailed bioinformatics analysis revealed the putative BGCs and the functions of the involved genes in the biosynthesis of the known compounds SF2738D (1), SF2738F (2), actinomycin D (3), and Actinomycin Xoβ (4). In the present study, complete-genome sequencing allowed us to rediscover known, clinically useful secondary metabolites in the newly isolated Streptomyces griseus SCSIO PteL053.

The gut microbiome–Does stool represent right?

Many stool-based gut microbiome studies have highlighted the importance of the microbiome. However, we hypothesized that stool is a poor proxy for the inner-colonic microbiome and that studying stool samples may be inadequate to capture the true inner-colonic microbiome. To test this hypothesis, we conducted prospective clinical studies with up to 20 patients undergoing an FDA-cleared gravity-fed colonic lavage without oral purgative pre-consumption. The objective of this study was to present the analysis of inner-colonic microbiota obtained non-invasively during the lavage and how these results differ from stool samples. The inner-colonic samples represented the descending, transverse, and ascending colon. All samples were analyzed for 16S rRNA and shotgun metagenomic sequences. The taxonomic, phylogenetic, and biosynthetic gene cluster analyses showed a distinctive biogeographic gradient and revealed differences between the sample types, especially in the proximal colon. The high percentage of unique information found only in the inner-colonic effluent highlights the importance of these samples and likewise the importance of collecting them using a method that can preserve these distinctive signatures. We proposed that these samples are imperative for developing future biomarkers, targeted therapeutics, and personalized medicine.

Integrated single-cell and transcriptome sequencing analyses develops a metastasis-based risk score system for prognosis and immunotherapy response in uveal melanoma.

Background: Uveal melanoma (UM) is the most frequent ocular neoplasm with a strong metastatic ability. The prognostic value of metastasis-associated genes (MAGs) of UM remains unclear. It is urgent to develop a prognostic score system according to the MAGs of UM. Methods: Unsupervised clustering was used to identify MAGs-based molecular subtypes. Cox methods were utilized to generate a prognostic score system. The prognostic ability of the score system was detected by plotting ROC and survival curves. The immune activity and underlying function were depicted by CIBERSORT GSEA algorithms. Results: Gene cluster analysis determined two MAGs-based subclusters in UM, which were remarkably different in clinical outcomes. A risk score system containing six MAGs (COL11A1, AREG, TIMP3, ADAM12, PRRX1 and GAS1) was set up. We employed ssGSEA to compare immune activity and immunocyte infiltration between the two risk groups. Notch, JAK/STAT and mTOR pathways were greatly enriched in the high-risk group. Furthermore, we observed that knockdown of AREG could inhibit UM proliferation and metastasis by in vitro assays. Conclusion: The MAGs-based subtype and score system in UM can enhance prognosis assessment, and the core system provides valuable reference for clinical decision-making.

Complete mitochondrial genome of Thuja sutchuenensis and its implications on evolutionary analysis of complex mitogenome architecture in Cupressaceae

BackgroundThe complex physical structure and abundant repeat sequences make it difficult to assemble the mitogenomes of seed plants, especially gymnosperms. Only approximately 33 mitogenomes of gymnosperms have been reported. However, as the most widely distributed and the second largest family among gymnosperms, Cupressaceae has only six assembled mitogenomes, including five draft mitogenomes and one complete mitogenome, which has greatly hindered the understanding of mitogenome evolution within this large family, even gymnosperms.ResultsIn this study, we assembled and validated the complete mitogenome of Thuja sutchuenensis, with a size of 2.4 Mb. Multiple sequence units constituted its complex structure, which can be reduced to three linear contigs and one small circular contig. The analysis of repeat sequences indicated that the numbers of simple sequence repeats increased during the evolutionary history of gymnosperms, and the mitogenome of Thuja sutchuenensis harboured abundant extra-long repeats (more than 5 kb). Additionally, the longest repeat sequence identified in these seven gymnosperms also came from the mitogenome of Thuja sutchuenensis, with a length of up to 47 kb. The analysis of colinear blocks and gene clusters both revealed that the orders of mitochondrial genes within gymnosperms was not conserved. The comparative analysis showed that only four tRNAs were shared by seven gymnosperms, namely, trnD-GUC, trnE-UUC, trnI-CAU and trnY-GUA. Furthermore, four genes have undergone potential positive selection in most gymnosperm species, namely, atp8, ccmB, mttB and sdh4.ConclusionWe successfully assembled the second complete mitogenome within Cupressaceae and verified that it consisted of multiple sequence units. Our study also indicated that abundant long repeats may contribute to the generation of the complex conformation of the mitogenome of Thuja sutchuenensis. The investigation of Thuja sutchuenensis’s mitogenome in our study provides new insight into further understanding the complex mitogenome architecture within gymnosperms.

Genome-wide analyzation and functional characterization on the TPS family provide insight into the biosynthesis of mono-terpenes in the camphor tree

Terpene synthase (TPS) plays an important role in terpenoids biosynthesis. Cinnamomum camphora (camphor tree) contains dozens of terpenoids with medicinal value, especially borneol, which has been widely used since ancient times. However, limited information is available regarding the genome-wide identification and characterization of the TPS family in the C. camphora. In this study, 82 CcTPS genes were identified from the camphor tree genome (CTG). Gene cluster and sequence syntenic analysis suggested that tandem duplication occurred within the TPS family of the CTG, especially for the TPS-b subfamily. The chemotype-specific gene expression analysis showed significantly differential expression patterns among six chemotypes. It is worth noting that three genes (CcTPS26, CcTPS49 and CcTPS72) exhibited relatively high expression in the borneol-type camphor tree, compared to the other five chemotypes. Further functional characterization of them indicated that they were all bornyl diphosphate synthases (BPPSs), which function in catalyzing GPP into BPP and then undergoes dephosphorylation to yield borneol. This is the first report that multiple BPPSs exist within a single species. Intriguingly, CcTPS49 and CcTPS72 lead to the generation of dextral-borneol, while CcTPS26 contributes to the biosynthesis of levo-borneol. In addition, the functional characterization of another six CcTPSs suggested that they are responsible for the biosynthesis of linalool, eucalyptol and several other monoterpenes in camphor tree. In conclusion, these novel results provide a foundation for further exploration of the role of the CcTPS gene family and shed light on a better understanding of the biosynthesis and accumulation of monoterpenes in camphor tree.

Metagenomics Shines Light on the Evolution of 'Sunscreen' Pigment Metabolism in the Teloschistales (Lichen-Forming Ascomycota).

Fungi produce a vast number of secondary metabolites that shape their interactions with other organisms and the environment. Characterising the genes underpinning metabolite synthesis is therefore key to understanding fungal evolution and adaptation. Lichenised fungi represent almost one-third of Ascomycota diversity and boast impressive secondary metabolites repertoires. However, most lichen biosynthetic genes have not been linked to their metabolite products. Here we used metagenomic sequencing to survey gene families associated with production of anthraquinones, UV-protectant secondary metabolites present in various fungi, but especially abundant in a diverse order of lichens, the Teloschistales (class Lecanoromycetes, phylum Ascomycota). We successfully assembled 24 new, high-quality lichenised fungal genomes de novo and combined them with publicly available Lecanoromycetes genomes from taxa with diverse secondary chemistry to produce a whole-genome tree. Secondary metabolite biosynthetic gene cluster (BGC) analysis showed that whilst lichen BGCs are numerous and highly dissimilar, core enzyme genes are generally conserved across taxa. This suggests metabolite diversification occurs via re-shuffling existing enzyme genes with novel accessory genes rather than BGC gains/losses or de novo gene evolution. We identified putative anthraquinone BGCs in our lichen dataset that appear homologous to anthraquinone clusters from non-lichenised fungi, suggesting these genes were present in the common ancestor of the subphylum Pezizomycotina. Finally, we identified unique transporter genes in Teloschistales anthraquinone BGCs that may explain why these metabolites are so abundant and ubiquitous in these lichens. Our results support the importance of metagenomics for understanding the secondary metabolism of non-model fungi such as lichens.

In Silico Prediction of Secondary Metabolites and Biosynthetic Gene Clusters Analysis of Streptomyces thinghirensis HM3 Isolated from Arid Soil

Natural products produced by microorganisms are considered an important resource of bioactive secondary metabolites, such as anticancer, antifungal, antibiotic, and immunosuppressive molecules. Streptomyces are the richest source of bioactive natural products via possessing a wide number of secondary metabolite biosynthetic gene clusters (SM-BGCs). Based on rapid development in sequencing technologies with advances in genome mining, exploring the newly isolated Streptomyces species for possible new secondary metabolites is mandatory to find novel natural products. The isolated Streptomyces thinghirensis strain HM3 from arid and sandy texture soil in Qassim, SA, exerted inhibition activity against tested animal pathogenic Gram-positive bacteria and pathogenic fungal species. In this study, we report the draft genome of S. thinghirensis strain HM3, which consists of 7,139,324 base pairs (bp), with an average G+C content of 71.49%, predicting 7949 open reading frames, 12 rRNA operons (5S, 16S, 23S) and 60 tRNAs. An in silico analysis of strain HM3 genome by the antiSMASH and PRISM 4 online software for SM-BGCs predicted 16 clusters, including four terpene, one lantipeptide, one siderophore, two polyketide synthase (PKS), two non-ribosomal peptide synthetase (NRPS) cluster)/NRPS-like fragment, two RiPP/RiPP-like (ribosomally synthesised and post-translationally modified peptide product), two butyrolactone, one CDPS (tRNA-dependent cyclodipeptide synthases), and one other (cluster containing a secondary metabolite-related protein that does not fit into any other category) BGC. The presented BGCs inside the genome, along with antibacterial and antifungal activity, indicate that HM3 may represent an invaluable source for new secondary metabolites.

Nonribosomal antibacterial peptides isolated from Streptomyces agglomeratus 5-1-3 in the Qinghai-Tibet Plateau

BackgroundNew antibiotics are urgently needed in clinical treatment of superdrug-resistant bacteria. Nonribosomal peptides (NRPs) are a major source of antibiotics because they exhibit structural diversity, and unique antibacterial mechanisms and resistance. Analysis of gene clusters of S. agglomeratus 5-1-3 showed that Clusters 3, 6, 12, 21, and 28 were used to synthesize NRPs. Here, we examined secondary metabolites of S. agglomeratus 5-1-3 isolated from soils in the Qinghai-Tibet Plateau, China, for NRPs with antibacterial activity.ResultsWe isolated a total of 36 Streptomyces strains with distinct colony morphological characteristics from 7 soil samples. We screened 8 Streptomyces strains resistant to methicillin-resistant Staphylococcus aureus (MRSA). We then selected S. agglomeratus 5-1-3 for further study based on results of an antibacterial activity test. Here, we isolated three compounds from S. agglomeratus 5-1-3 and characterized their properties. The crude extract was extracted with ethyl acetate and purified with column chromatography and semipreparative high-performance liquid chromatography (HPLC). We characterized the three compounds using NMR analyses as echinomycin (1), 5,7,4ʹ-trihydroxy-3.3′,5′-trimethoxy flavone (2), and 2,6,2′, 6′-tetramethoxy-4,4-bis(2,3-epoxy-1-hydroxypropyl)-biphenyl (3). We tested the antibacterial activity of pure compounds from strain 5-1-3 with the Oxford cup method. NRP echinomycin (1) showed excellent anti-MRSA activity with a minimum inhibitory concentration (MIC) of 2.0 μg/mL. Meanwhile, MIC of compound 2 and 3 was 128.0 μg/mL for both. In addition, 203 mg of echinomycin was isolated from 10 L of the crude extract broth of strain 5-1-3.ConclusionIn this study, S. agglomeratus 5-1-3 with strong resistance to MRSA was isolated from the soils in the Qinghai-Tibet Plateau. Strain 5-1-3 had a high yield of echinomycin (1) an NRP with a MIC of 2 μg/mL against MRSA. We propose that echinomycin derived from S. agglomeratus 5-1-3 may be a potent antibacterial agent for pharmaceutical use.