Network pharmacology-based investigation of the effects of Shenqi Fuzheng injection on glioma proliferation and migration via the SRC/PI3K/AKT signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: In the clinic, Shenqi Fuzheng Injection (SFI) is used as an adjuvant for cancer chemotherapy. However, the molecular mechanism is unclear. AIM OF THE STUDY: We screened potential targets of SFI action on gliomas by network pharmacology and performed experiments to validate possible molecular mechanisms against gliomas. MATERIALS AND METHODS: We consulted relevant reports on the SFI and glioma incidence from PubMed and Web of Science and focused on the mechanism through which the SFI inhibits glioma. According to the literature, two primary SFI components-Codonopsis pilosula (Franch.) Nannf. and Astragalus membranaceus (Fisch.) Bunge-have been found. All plant names have been sourced from "The Plant List" (www.theplantlist.org). The cell lines U87, T98G and GL261 were used in this study. The inhibitory effects of SFI on glioma cells U87 and T98G were detected by CCK-8 assay, EdU, plate cloning assay, scratch assay, Transwell assay, immunofluorescence, flow cytometry and Western blot. A subcutaneous tumor model of C57BL/6 mice was constructed using GL261 cells, and the SFI was evaluated by HE staining and immunohistochemistry. The targets of glioma and the SFI were screened using network pharmacology. RESULTS: A total of 110 targets were enriched, and a total of 26 major active components in the SFI were investigated. There were a total of 3,343 targets for gliomas, of which 79 targets were shared between the SFI and glioma tissues. SFI successfully prevented proliferation and caused cellular S-phase blockage in U87 and T98G cells, thus decreasing their growth. Furthermore, SFI suppressed cell migration by downregulating EMT marker expression. According to the results of the in vivo tests, the SFI dramatically decreased the development of tumors in a transplanted tumour model. Network pharmacological studies revealed that the SRC/PI3K/AKT signaling pathway may be the pathway through which SFI exerts its anti-glioma effects. CONCLUSIONS: The findings revealed that the SRC/PI3K/AKT signaling pathway may be involved in the mechanism through which SFI inhibits the proliferation and migration of glioma cells.

Signalling interaction between ß-catenin and other signalling molecules during osteoarthritis development.

Osteoarthritis (OA) is the most prevalent disorder of synovial joint affecting multiple joints. In the past decade, we have witnessed conceptual switch of OA pathogenesis from a 'wear and tear' disease to a disease affecting entire joint. Extensive studies have been conducted to understand the underlying mechanisms of OA using genetic mouse models and ex vivo joint tissues derived from individuals with OA. These studies revealed that multiple signalling pathways are involved in OA development, including the canonical Wnt/ß-catenin signalling and its interaction with other signalling pathways, such as transforming growth factor ß (TGF-ß), bone morphogenic protein (BMP), Indian Hedgehog (Ihh), nuclear factor κB (NF-κB), fibroblast growth factor (FGF), and Notch. The identification of signalling interaction and underlying mechanisms are currently underway and the specific molecule(s) and key signalling pathway(s) playing a decisive role in OA development need to be evaluated. This review will focus on recent progresses in understanding of the critical role of Wnt/ß-catenin signalling in OA pathogenesis and interaction of ß-catenin with other pathways, such as TGF-ß, BMP, Notch, Ihh, NF-κB, and FGF. Understanding of these novel insights into the interaction of ß-catenin with other pathways and its integration into a complex gene regulatory network during OA development will help us identify the key signalling pathway of OA pathogenesis leading to the discovery of novel therapeutic strategies for OA intervention.

Postoperative Antiosteoporotic Treatment with Zoledronic Acid Improves Rotator Cuff Healing but Does Not Improve Outcomes in Female Patients with Postmenopausal Osteoporosis: A Prospective, Single-Blinded, Randomized Study.

PURPOSE: To investigate the effect of the antiosteoporotic agent zoledronic acid (ZA) on rotator cuff healing and clinical outcomes in patients with postmenopausal osteoporosis. METHODS: We prospectively enrolled 138 female patients with postmenopausal osteoporosis who were scheduled to undergo arthroscopic rotator cuff repair (ARCR) from March 2020 to March 2021. Patients were randomly allocated to the ZA group (ARCR followed by intravenous ZA infusions at postoperative Day 1 and 1 year later) and the control group (ARCR alone). All patients were followed up for 24 months. Tendon healing was evaluated by ultrasonography at 6 weeks and 24 months after surgery. The American Shoulder and Elbow Surgeons (ASES) score, Western Ontario Rotator Cuff (WORC) index, and Numeric Rating Scale (NRS) for pain were recorded at each follow-up, and the minimal clinically important difference (MCID) was calculated. RESULTS: A total of 124 patients were included in the final analysis, 61 in the ZA group and 63 in the control group. There was no statistically significant difference in participant characteristics between the 2 groups. The ZA group had a significantly higher tendon healing rate than the control group at 2 years after surgery (odds ratio = 5.0; 95% confidence interval [CI], 1.4-18.7; P = .014). Regarding clinical outcomes, 100% of patients exceeded the MCID in both groups, and no significant differences were found at 2 years after surgery between the 2 groups (ASES: 2.5 [95% CI, -2.2 to 7.2; P = .291]; WORC index: 4.5 [95% CI, -0.117 to 9.117; P = .056]; NRS: -0.1 [95% CI, -0.3 to 0.1; P = .394]). CONCLUSIONS: Antiosteoporotic treatment with ZA reduced the retear rate but did not significantly influence the clinical outcomes after ARCR in female patients with postmenopausal osteoporosis. Outcomes of ARCR showed good results in both groups and exceeded the MCID. LEVEL OF EVIDENCE: Level I, randomized controlled trial.

A comprehensive review of TGA transcription factors in plant growth, stress responses, and beyond.

TGA transcription factors (TFs), belonging to the D clade of the basic region leucine zipper (bZIP) family, exhibit a specific ability to recognize and bind to regulatory elements with TGACG as the core recognition sequence, enabling the regulation of target gene expression and participation in various biological regulatory processes. In plant growth and development, TGA TFs influence organ traits and phenotypes, including initial root length and flowering time. They also play a vital role in responding to abiotic stresses like salt, drought, and cadmium exposure. Additionally, TGA TFs are involved in defending against potential biological stresses, such as fungal bacterial diseases and nematodes. Notably, TGA TFs are sensitive to the oxidative-reductive state within plants and participate in pathways that aid in the elimination of reactive oxygen species (ROS) generated during stressful conditions. TGA TFs also participate in multiple phytohormonal signaling pathways (ABA, SA, etc.). This review thoroughly examines the roles of TGA TFs in plant growth, development, and stress response. It also provides detailed insights into the mechanisms underlying their involvement in physiological and pathological processes, and their participation in plant hormone signaling. This multifaceted exploration distinguishes this review from others, offering a comprehensive understanding of TGA TFs.

Risk of metabolic abnormalities in osteoarthritis: a new perspective to understand its pathological mechanisms.

Although aging has traditionally been viewed as the most important risk factor for osteoarthritis (OA), an increasing amount of epidemiological evidence has highlighted the association between metabolic abnormalities and OA, particularly in younger individuals. Metabolic abnormalities, such as obesity and type II diabetes, are strongly linked to OA, and they affect both weight-bearing and non-weight-bearing joints, thus suggesting that the pathogenesis of OA is more complicated than the mechanical stress induced by overweight. This review aims to explore the recent advances in research on the relationship between metabolic abnormalities and OA risk, including the impact of abnormal glucose and lipid metabolism, the potential pathogenesis and targeted therapeutic strategies.

Applying the digital data and the bioinformatics tools in SARS-CoV-2 research.

Bioinformatics has been playing a crucial role in the scientific progress to fight against the pandemic of the coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The advances in novel algorithms, mega data technology, artificial intelligence and deep learning assisted the development of novel bioinformatics tools to analyze daily increasing SARS-CoV-2 data in the past years. These tools were applied in genomic analyses, evolutionary tracking, epidemiological analyses, protein structure interpretation, studies in virus-host interaction and clinical performance. To promote the in-silico analysis in the future, we conducted a review which summarized the databases, web services and software applied in SARS-CoV-2 research. Those digital resources applied in SARS-CoV-2 research may also potentially contribute to the research in other coronavirus and non-coronavirus viruses.

LncRNA H19 mediates BMP9-induced angiogenesis in mesenchymal stem cells by promoting the p53-Notch1 angiogenic signaling axis.

BMP9 mediated osteogenic differentiation mechanisms of MSCs were widely explored, however, mechanisms of BMP9-induced angiogenesis still need to be clarified. We previously characterized that Notch1 promoted BMP9-induced osteogenesis-angiogenesis coupling process in mesenchymal stem cells (MSCs). Here, we explored the underlying mechanisms of lncRNA H19 (H19) mediated regulation of BMP9-induced angiogenesis through activating Notch1 signaling. We demonstrated that basal expression level of H19 was high in MSCs, and silencing H19 attenuates BMP9-induced osteogenesis and angiogenesis of MSCs both in vitro and in vivo. Meanwhile, we identified that BMP9-induced production of CD31+ cells was indispensable for BMP9-induced bone formation, and silencing H19 dramatically blocked BMP9-induced production of CD31+ cells. In addition, we found that down-regulation of H19 inhibited BMP9 mediated blood vessel formation and followed subsequent bone formation in vivo. Mechanistically, we clarified that H19 promoted p53 phosphorylation by direct interacting and phosphorylating binding, and phosphorylated p53 potentiated Notch1 expression and activation of Notch1 targeting genes by binding on the promoter area of Notch1 gene. These findings suggested that H19 regulated BMP9-induced angiogenesis of MSCs by promoting the p53-Notch1 angiogenic signaling axis.

The NSP4 T492I mutation increases SARS-CoV-2 infectivity by altering non-structural protein cleavage.

The historically dominant SARS-CoV-2 Delta variant and the currently dominant Omicron variants carry a T492I substitution within the non-structural protein 4 (NSP4). Based on in silico analyses, we hypothesized that the T492I mutation increases viral transmissibility and adaptability, which we confirmed with competition experiments in hamster and human airway tissue culture models. Furthermore, we showed that the T492I mutation increases the replication capacity and infectiveness of the virus and improves its ability to evade host immune responses. Mechanistically, the T492I mutation increases the cleavage efficiency of the viral main protease NSP5 by enhancing enzyme-substrate binding, which increases production of nearly all non-structural proteins processed by NSP5. Importantly, the T492I mutation suppresses viral-RNA-associated chemokine production in monocytic macrophages, which may contribute to the attenuated pathogenicity of Omicron variants. Our results highlight the importance of NSP4 adaptation in the evolutionary dynamics of SARS-CoV-2.

Long noncoding RNA (lncRNA) H19: An essential developmental regulator with expanding roles in cancer, stem cell differentiation, and metabolic diseases.

Recent advances in deep sequencing technologies have revealed that, while less than 2% of the human genome is transcribed into mRNA for protein synthesis, over 80% of the genome is transcribed, leading to the production of large amounts of noncoding RNAs (ncRNAs). It has been shown that ncRNAs, especially long non-coding RNAs (lncRNAs), may play crucial regulatory roles in gene expression. As one of the first isolated and reported lncRNAs, H19 has gained much attention due to its essential roles in regulating many physiological and/or pathological processes including embryogenesis, development, tumorigenesis, osteogenesis, and metabolism. Mechanistically, H19 mediates diverse regulatory functions by serving as competing endogenous RNAs (CeRNAs), Igf2/H19 imprinted tandem gene, modular scaffold, cooperating with H19 antisense, and acting directly with other mRNAs or lncRNAs. Here, we summarized the current understanding of H19 in embryogenesis and development, cancer development and progression, mesenchymal stem cell lineage-specific differentiation, and metabolic diseases. We discussed the potential regulatory mechanisms underlying H19's functions in those processes although more in-depth studies are warranted to delineate the exact molecular, cellular, epigenetic, and genomic regulatory mechanisms underlying the physiological and pathological roles of H19. Ultimately, these lines of investigation may lead to the development of novel therapeutics for human diseases by exploiting H19 functions.

Metformin improves fibroblast metabolism and ameliorates arthrofibrosis in rats.

Background: Emerging studies have suggested an essential role of fibroblast metabolic reprogramming in the pathogenesis of arthrofibrosis. The metabolic modulator metformin appears to be a therapeutic candidate for fibrotic disorders. However, whether metformin could alleviate arthrofibrosis has not been defined. In this study we have determined if treatment with metformin has beneficial effect on arthrofibrosis and its underlying mechanism. Methods: Articular capsule samples were collected from patients with/without arthrofibrosis to perform gene and protein expression analysis. Arthrofibrosis animal model was established to examine the anti-fibrotic effect of metformin. Cell culture experiments were conducted to determine the mechanism by which metformin inhibits fibroblast activation. Results: We found that glycolysis was upregulated in human fibrotic articular capsules. In an arthrofibrosis animal model, intra-articular injection of metformin mitigated inflammatory reactions, downregulated expression of both fibrotic and glycolytic markers, improved range of motion (ROM) of the joint, and reduced capsular fibrosis and thickening. At the cellular level, metformin inhibited the activation of fibroblasts and mitigated the abundant influx of glucose into activated fibroblasts. Interestingly, metformin prompted a metabolic shift from oxidative phosphorylation to aerobic glycolysis in activated fibroblasts, resulting in the anti-fibrotic effect of metformin. Conclusion: Metformin decreased glycolysis, causing a metabolic shift toward aerobic glycolysis in activated fibroblasts and has beneficial effect on the treatment of arthrofibrosis.The translational potential of this article: The findings of this study demonstrated the therapeutic effect of metformin on arthrofibrosis and defined novel targets for the treatment of articular fibrotic disorders.

Anti-oomycete ability of scopolamine against Phytophthora infestans, a terrible pathogen of potato late blight.

BACKGROUND: Phytophthora infestans causes late blight, threatening potato production. The tropane alkaloid scopolamine from some industrial plants (Datura, Atropa, etc.) has a broad-spectrum bacteriostatic effect, but its effect on P. infestans is unknown. RESULTS: In the present study, scopolamine inhibited the mycelial growth of phytopathogenic oomycete P. infestans, and the half-maximal inhibitory concentration (IC50 ) was 4.25 g L-1 . The sporangia germination rates were 61.43%, 16.16%, and 3.99% at concentrations of zero (control), 0.5 IC50 , and IC50 , respectively. The sporangia viability of P. infestans was significantly reduced after scopolamine treatment through propidium iodide and fluorescein diacetate staining, speculating that scopolamine destroyed cell membrane integrity. The detached potato tuber experiment demonstrated that scopolamine lessened the pathogenicity of P. infestans in potato tubers. Under stress conditions, scopolamine showed good inhibition of P. infestans, indicating that scopolamine could be used in multiple adverse conditions. The combination effect of scopolamine and the chemical pesticide Infinito on P. infestans was more effective than the use of scopolamine or Infinito alone. Moreover, transcriptome analysis suggested that scopolamine leaded to a downregulation of most P. infestans genes, functioning in cell growth, cell metabolism, and pathogenicity. CONCLUSION: To our knowledge, this is the first study to detect scopolamine inhibitory activity against P. infestans. Also, our findings highlight the potential of scopolamine as an eco-friendly option for controlling late blight in the future. © 2023 Society of Chemical Industry.

The Necessity of Implant Removal after Fixation of Thoracolumbar Burst Fractures-A Systematic Review.

BACKGROUND: Thoracolumbar burst fractures are a common traumatic vertebral fracture in the spine, and pedicle screw fixation has been widely performed as a safe and effective procedure. However, after the stabilization of the thoracolumbar burst fractures, whether or not to remove the pedicle screw implant remains controversial. This review aimed to assess the benefits and risks of pedicle screw instrument removal after fixation of thoracolumbar burst fractures. METHODS: Data sources, including PubMed, EMBASE, Cochrane Library, Web of Science, Google Scholar, and Clinical trials.gov, were comprehensively searched. All types of human studies that reported the benefits and risks of implant removal after thoracolumbar burst fractures, were selected for inclusion. Clinical outcomes after implant removal were collected for further evaluation. RESULTS: A total of 4051 papers were retrieved, of which 35 studies were eligible for inclusion in the review, including four case reports, four case series, and 27 observational studies. The possible risks of pedicle screw removal after fixation of thoracolumbar burst fractures include the progression of the kyphotic deformity and surgical complications (e.g., surgical site infection, neurovascular injury, worsening pain, revision surgery), while the potential benefits of pedicle screw removal mainly include improved segmental range of motion and alleviated pain and disability. Therefore, the potential benefits and possible risks should be weighed to support patient-specific clinical decision-making about the removal of pedicle screws after the successful fusion of thoracolumbar burst fractures. CONCLUSIONS: There was conflicting evidence regarding the benefits and harms of implant removal after successful fixation of thoracolumbar burst fractures, and the current literature does not support the general recommendation for removal of the pedicle screw instruments, which may expose the patients to unnecessary complications and costs. Both surgeons and patients should be aware of the indications and have appropriate expectations of the benefits and risks of implant removal. The decision to remove the implant or not should be made individually and cautiously by the surgeon in consultation with the patient. Further studies are warranted to clarify this issue. LEVEL OF EVIDENCE: level 1.

Lactate Mediates the Bone Anabolic Effect of High-Intensity Interval Training by Inducing Osteoblast Differentiation.

BACKGROUND: High-intensity interval training (HIIT) reportedly improves bone metabolism and increases bone mineral density (BMD). The purpose of the present study was to investigate whether lactate mediates the beneficial effects of exercise on BMD, bone microarchitecture, and biomechanical properties in an established osteoporotic animal model. In addition, we hypothesized that lactate-induced bone augmentation is achieved through enhanced osteoblast differentiation and mineralization. METHODS: A total of 50 female C57BL/6 mice were randomly allocated into 5 groups: the nonovariectomized group, the ovariectomized group (OVX), the HIIT group (OVX + HIIT), the HIIT with lactate transporter inhibition group (OVX + HIIT + INH), and the lactate subcutaneous injection group (OVX + LAC). After 7 weeks of intervention, bone mass, bone strength, and bone formation/resorption processes were evaluated via microcomputed tomography (micro-CT), biomechanical testing, histological analysis, and serum biochemical assays; in vitro studies were performed to explore the bone anabolic effect of lactate at the cellular level. RESULTS: Micro-CT revealed significantly increased BMD in both the OVX + HIIT group (mean difference, 41.03 mg hydroxyapatite [HA]/cm 3 [95% CI, 2.51 to 79.54 mg HA/cm 3 ]; p = 0.029) and the OVX + LAC group (mean difference, 40.40 mg HA/cm 3 [95% CI, 4.08 to 76.71 mg HA/cm 3 ]; p = 0.031) compared with the OVX group. Biomechanical testing demonstrated significantly improved mechanical properties in those 2 groups. However, the beneficial effects of exercise on bone microstructure and biomechanics were largely abolished by blocking the lactate transporter. Notably, histological and biochemical results indicated that increased bone formation was responsible for the bone augmentation effects of HIIT and lactate. Cell culture studies showed a marked increase in the expression of osteoblastic markers with lactate treatment, which could be eliminated by blocking the lactate transporter. CONCLUSIONS: Lactate may have mediated the bone anabolic effect of HIIT in osteoporotic mice, which may have resulted from enhanced osteoblast differentiation and mineralization. CLINICAL RELEVANCE: Lactate may mediate the bone anabolic effect of HIIT and serve as a potential inexpensive therapeutic strategy for bone augmentation.

PI3K-Akt signaling regulates BMP2-induced osteogenic differentiation of mesenchymal stem cells (MSCs): A transcriptomic landscape analysis.

Bone morphogenetic protein 2 (BMP2) effectively induced mesenchymal stem cells (MSCs) osteogenic differentiation hold great potential for bone tissue engineering. However, a global mechanistic view of BMP2-induced osteogenic differentiation of MSCs remains to be fully elucidated. Here, human umbilical cord-derived MSCs (UC-MSCs) were induced with BMP2, three days and five days later, total RNA were extracted and subjected to RNA-sequencing (RNA-Seq) followed with bioinformatic analysis. Osteogenic differentiation abilities were evaluated with Alkaline phosphatase (ALP) staining and osteogenic differentiation marker expression at both mRNA and protein levels. We identified that adenoviral vectors effectively transduced in UC-MSCs and expressed BMP2 in high efficiency. Both on day 3 and day 5, differentially expressed genes (DEGs) were highly enriched in PI3K-Akt signaling pathway. As for the common DEGs among total BMP2 group vs control group, BMP2 (day 3) versus control (day 3) and BMP2 (day 5) versus control (day 5), there were 105 DGEs and highly enriched in PI3K-Akt signaling pathway. Finally, we found that PI3K-Akt signaling inhibitor dramatically inhibited BMP2-iduced osteogenic differentiation of UC-MSCs. We firstly identified that PI3K-Akt signaling pathway plays a pivotal role in BMP2-induced osteogenic differentiation of MSCs, which may apply a new perspective for BMP2 based bone tissue engineering.

AMPK activator decelerates osteoarthritis development by inhibition of ß-catenin signaling in chondrocytes.

Background: Osteoarthritis (OA) is a common degenerative joint disease with significant negative impact on the quality of life. It has been reported that abnormal upregulation of ß-catenin signaling could lead to OA development; however, the upstream regulatory mechanisms of ß-catenin signaling have not been determined. Methods: Primary rat chondrocytes and ATDC5 chondrocyte cell line were stimulated with AKT2 and treated with or without metformin, an adenosine 5'-monophosphate-activated protein kinase (AMPK) activator. Westerrn blot analysis, luciferase reporter assay and immunofluorescent (IF) staining were performed to examine changes in ß-cateninS552 phosphorylation and ß-catenin nuclear translocation in ATDC5 cells and in primary chondrocytes. Results: We found that metformin inhibited ß-cateninS552 phosphorylation in ATDC5 cells and in primary chondrocytes in a time-dependent manner. Metformin inhibited ß-catenin nuclear translocation and ß-catenin reporter activity. In addition, metformin also attenuated the expression of ß-catenin downstream target genes. We also demonstrated that metformin inhibited ß-cateninS552 phosphorylation in articular cartilage in mice. Conclusion: These findings suggest that metformin may exert its chondro-protective effect at least in part through the inhibition of ß-catenin signaling in chondrocytes. The translational potential of this article: This study demonstrated the interaction between AMPK and ß-catenin signaling in chondrocytes and defined novel molecular targets for the treatment of OA disease.

The natural product salicin alleviates osteoarthritis progression by binding to IRE1α and inhibiting endoplasmic reticulum stress through the IRE1α-IκBα-p65 signaling pathway.

Despite the high prevalence of osteoarthritis (OA) in older populations, disease-modifying OA drugs (DMOADs) are still lacking. This study was performed to investigate the effects and mechanisms of the small molecular drug salicin (SA) on OA progression. Primary rat chondrocytes were stimulated with TNF-α and treated with or without SA. Inflammatory factors, cartilage matrix degeneration markers, and cell proliferation and apoptosis markers were detected at the mRNA and protein levels. Cell proliferation and apoptosis were evaluated by EdU assays or flow cytometric analysis. RNA sequencing, molecular docking and drug affinity-responsive target stability analyses were used to clarify the mechanisms. The rat OA model was used to evaluate the effect of intra-articular injection of SA on OA progression. We found that SA rescued TNF-α-induced degeneration of the cartilage matrix, inhibition of chondrocyte proliferation, and promotion of chondrocyte apoptosis. Mechanistically, SA directly binds to IRE1α and occupies the IRE1α phosphorylation site, preventing IRE1α phosphorylation and regulating IRE1α-mediated endoplasmic reticulum (ER) stress by IRE1α-IκBα-p65 signaling. Finally, intra-articular injection of SA-loaded lactic-co-glycolic acid (PLGA) ameliorated OA progression by inhibiting IRE1α-mediated ER stress in the OA model. In conclusion, SA alleviates OA by directly binding to the ER stress regulator IRE1α and inhibits IRE1α-mediated ER stress via IRE1α-IκBα-p65 signaling. Topical use of the small molecular drug SA shows potential to modify OA progression.

Complete Genome Sequence Data of a Novel Streptomyces sp. Strain A2-16, a Potential Biological Control Agent for Potato Late Blight.

Streptomyces sp. strain A2-16 was recently isolated from potato root zone soil, and it could inhibit the hyphal growth of Phytophthora infestans. The A2-16 genome consisted of one chromosome of 9,765,518 bp and one plasmid of 30,948 bp with GC contents of 70.88% and 68.39%, respectively. A total of 8,518 predicted coding genes, 3 ncRNA,73 tRNA,18 rRNA genes, and 28 secondary metabolite biosynthesis gene clusters were identified. The products of the gene clusters included bioactive polyketides, terpenes, and siderophores, which might contribute to host plants against disease. The average nucleotide identity (ANI) value (82.88-91.41%) among the genome of A2-16 and other Streptomyces species suggested it might not belong to any previously sequenced species in the Streptomyces genus.

Nucleocapsid mutations R203K/G204R increase the infectivity, fitness, and virulence of SARS-CoV-2.

Previous work found that the co-occurring mutations R203K/G204R on the SARS-CoV-2 nucleocapsid (N) protein are increasing in frequency among emerging variants of concern or interest. Through a combination of in silico analyses, this study demonstrates that R203K/G204R are adaptive, while large-scale phylogenetic analyses indicate that R203K/G204R associate with the emergence of the high-transmissibility SARS-CoV-2 lineage B.1.1.7. Competition experiments suggest that the 203K/204R variants possess a replication advantage over the preceding R203/G204 variants, possibly related to ribonucleocapsid (RNP) assembly. Moreover, the 203K/204R virus shows increased infectivity in human lung cells and hamsters. Accordingly, we observe a positive association between increased COVID-19 severity and sample frequency of 203K/204R. Our work suggests that the 203K/204R mutations contribute to the increased transmission and virulence of select SARS-CoV-2 variants. In addition to mutations in the spike protein, mutations in the nucleocapsid protein are important for viral spreading during the pandemic.