Complete Genome Sequence of Streptomyces sp. HP-A2021, a Promising Bacterium for Natural Product Discovery.

Streptomyces are one of the most prolific sources of bioactive and structurally diverse secondary metabolites for natural product drug discovery. Genome sequencing and bioinformatics analysis revealed that the genomes of Streptomyces harbor a wealth of cryptic secondary metabolite biosynthetic gene clusters that could encode novel compounds. In this work, a genome mining approach was employed to investigate the biosynthetic potential of Streptomyces sp. HP-A2021, isolated from rhizosphere soil of Ginkgo biloba L. The complete genome of HP-A2021 was sequenced and contained the 9,607,552 base pair linear chromosome with a GC content of 71.07%. The annotation results revealed the presence of 8534 CDSs, 76 tRNA genes, and 18 rRNA genes in HP-A2021. The highest dDDH and ANI values based on genome sequences between HP-A2021 and the most closely related type strain, Streptomyces coeruleorubidus JCM 4359, were 64.2% and 92.41%, respectively. In total, 33 secondary metabolite biosynthetic gene clusters with an average length of 105,594 bp were identified, including the putative thiotetroamide, alkylresorcinol, coelichelin, and geosmin. The antibacterial activity assay confirmed that the crude extracts of HP-A2021 showed potent antimicrobial activity against human pathogenic bacteria. Our study demonstrated that Streptomyces sp. HP-A2021 will propose a potential use in biotechnological and novel bioactive secondary metabolite biosynthetic applications.

Protective effect of cyclosporine A in the treatment of severe hydronephrosis in a rabbit renal pelvic perfusion model

Background/aim: Cyclosporine A (CsA), a traditional immunosuppressive compound, has been reported to specifically prevent isch-emia reperfusion tissue injury via apoptosis pathway. This study aimed to explore the renoprotective effects of CsA on the kidneys of rabbits undergoing renal pelvic perfusion. Materials and methods: A total of 30 rabbits were randomly assigned into a control group (n = 6) and an experimental group (n = 24). The experimental group underwent a surgical procedure that induced severe hydronephrosis and was then stochastically divided into 4 groups (S1, S1', S2, and S2'), consisting of 6 rabbits each. Groups S1 and S1' were perfused with 20 mmHg of fluid, while groups S2 and S2' were perfused with 60 mmHg of fluid. Administration to groups S1' and S2' was done intravenously, with CsA once a day for 1 week before perfusion. In the control group, after severe hydronephrosis was induced, a sham operation was performed in a second laparoto-my. Acute kidney damage was evaluated using hematoxylin and eosin staining, in addition to analyzing the mitochondrial ultrastructure and mitochondrial membrane potential (MMP). The cytochrome C (CytC) and neutrophil gelatinase-associated lipocalin (NGAL) expression were examined immunohistochemically using Western blotting and reverse transcription-polymerase chain reaction. Results: It was found that the renal histopathological damage was ameliorated, mitochondrial vacuolization was lower, MMP was high-er, and the CytC and NGAL contents were decreased after drug intervention (groups S1' and S2') when compared to the experimental groups (S1 and S2). Furthermore, there was no difference between drug intervention groups S1' and S2'. Conclusion: These results suggest that CsA can attenuate renal damage from severe hydronephrosis induced by renal pelvic perfusion in rabbits. It plays a protective role in the acute kidney injury process, possibly through increased MMP and mitochondrial changes.