BMC Biotechnology最新文献

Novel antifungal compounds effective against phytopathogenic fungiwere identified by evaluating an n-butanol extract obtained from the fermentation broth of Streptomyces diastatochromogenes strain No.1628. The extract exhibited had strong antifungal activity against Botrytis cinerea, Fusarium oxysporum, and Rhizoctonia solani, markedly reducing the spore germination rates of F. oxysporum and B. cinerea to 25.65% and 28.23%, respectively, at a concentration of 35 mg/L. In vivo efficacy assays further demonstated that the extract achieved disease control efficiencies of 53.42% and 55.68% against Rhizoctonia rot following irrigation at 10 mg/L for 14 and 21 days, respectively. Subsequent chemical investigation led to the isolation of five antifungal compounds from the n-butanol extract: the novel tetraene macrolide, which was structurally elucidated through spectroscopic analysis as (7E,12Z,13E,15E,17E,19E)-21- ((4-amino-3,5-dihydroxy-6-methyltetrahydro-2 H-pyran-2-yl)oxy -)-12-ethylidene-1,5,6,25-tetrahydroxy-11-methyl-9-oxo-10,27-dioxabi-cyclo[21.3.1] -heptacosa-7,13,15,17,19-pentaene-24-carboxylic acid (compound 1), and four other already known antifungal agents, namely tetrin B (2), tetramycin A (3), toyocamycin (4) and anisomycin (5). Compound 1 exhibited potent inhibitory activity against the hyphal growth of R. solani, F. oxysporum, and B. cinerea, with IC₅₀ values of 0.20, 1.28, and 1.53 µg/mL, respectively. These fundings underscore S. diastatochromogenes as a promising microbial source for the discovery of natural antifungal agents.

Background: Tuberculosis (TB) and lung cancer (LC) are among the leading causes of death worldwide and present serious challenges in diagnosis and treatment. Therefore, developing new strategies for their treatment is crucial. MicroRNAs (miRNAs) are biological molecules that play a critical role in regulating essential processes, such as apoptosis and autophagy, in TB and LC by targeting specific genes. Recently, carbon nanotubes functionalized with Polyethyleneimine (CNT-PEI) to deliver miRNAs to target cells have been investigated to enhance therapeutic effects.

Methods: In this study, miR-146a was transfected into LC (A549), macrophages infected with TB (THP1), and healthy lung cells (MRC5) using CNT-PEI. Then, the expression of miR-146a and its target gene, TNF receptor-associated factor-6 (TRAF6), and other genes involved in apoptosis and autophagy pathways including BCL-2, IL-6, tumor necrosis factor-alpha (TNFα), were measured using Real-Time PCR. Finally, the effect of overexpression of miR-146a on these genes was investigated in all three cell lines.

Result: The results showed successful transfection of miR-146a using the CNT-PEI nano delivery system in LC and TB cell models. Then, increased expression of miR-146 increased apoptosis and autophagy by targeting the TRAF6 gene and affecting other genes such as BCL-2, IL-6, and TNFα through the NF-kB signaling pathway.

Conclusion: The findings suggest an important role for miR-146a in TB and LC, which regulates inflammatory responses and treats these diseases. However, further studies are needed on using CNT-PEI in vivo, as well as the balance between local anti-inflammatory and non-inflammatory factors.

Background: The repair of bone defects remains a significant clinical challenge. Although magnesium (Mg)-based biomimetic scaffolds are widely utilized for bone defect repair, the release of Mg²⁺ ions often leads to an alkaline microenvironment, thereby adversely affecting bone regeneration. Regenerative medicine strategies that leverage the recruitment of endogenous bone marrow mesenchymal stem cells (BMSCs) offer a novel approach to treating bone defects.

Methods: In this study, we employed poly(L-lactic acid) (PLLA) and polyethylene glycol (PEG) as shell materials and nanomagnesium oxide (nMgO) combined with gelatin (G) as core materials to fabricate coaxial fibre membranes with a "core‒shell" structure via coaxial electrospinning technology. Additionally, we grafted the BMSC-affinitive peptide E7 (EPLQLKM) onto the fibres to achieve specific recruitment of endogenous BMSCs.

Results: Morphological and structural analyses confirmed the successful formation of the "core‒shell" structure of the fibre membranes. Grafting E7 peptides enhanced the hydrophilicity and mechanical properties of the fibre membranes and maintained pH stability in vitro. In vitro experiments demonstrated that the functionalized fibre membranes significantly promoted BMSC proliferation, migration, and osteogenic differentiation. When implanted into a rat cranial defect model, we observed the formation of new bone tissue and the repair of the bone defect.

Conclusions: E7 peptide-functionalized coaxial fibre membranes effectively facilitated bone defect repair by promoting the recruitment and osteogenic differentiation of BMSCs, demonstrating substantial potential for tissue engineering applications.

Virus-like particles (VLPs) offer potentially high-immunogenicity/low-cost vaccine platforms. SARS-CoV-2 VLPs production is achieved via transient transfection of genes encoding viral structural proteins, but is costly and difficult to scale up. To address this problem, stable VLPs-producing cell lines are desirable. In this study, we achieved efficient VLPs production by HEK293T cells after transient transfection of four plasmids containing the S, M, N, and E genes with optimized codons. Moreover, spike-specific IgG antibodies were elicited in mice, though no significant neutralizing activity was detected at the tested time points. Transmission electron microscopy (TEM) revealed that the VLPs diameters were approximately 120 nm. However, overexpression of E or M proteins was toxic to the cells. Stable cell lines were established by constructing two plasmids, in which E and M expression was controlled by an inducible Tet-on promoter and they were placed adjacent to S and N, respectively. A HEK293T cell line for stable expression of SARS-CoV-2 VLPs was established by co-selection with two antibiotics, puromycin and blasticidin. Specific IgG antibodies against the S protein were detected in mice immunized with VLPs formulated with the alum adjuvant. Our findings provide an effective approach for large-scale production of SARS-CoV-2 VLPs as vaccine candidates.

Background: Biomaterials have been extensively utilized in the field of tissue regeneration and repair. The objective of this study was to develop and assess the efficacy of ECM-G@bFGF in the repair of sciatic nerve injuries.

Methods: The extracellular matrix (ECM) of the sciatic nerve was extracted using an acellularization technique. Functionalized ECM-G@bFGF was prepared by cross-linking a mixture of basic fibroblast growth factor (bFGF) and genipin(G) into the ECM scaffold. The physicochemical characteristics, biocompatibility, and sustained-release properties of ECM-G@bFGF were systematically evaluated. Additionally, in vivo experiments were conducted to assess the efficacy of ECM-G@bFGF in promoting peripheral nerve regeneration and repair.

Results: The results demonstrated that the thread-like spatial structure of the sciatic nerve was preserved within the extracellular matrix (ECM) after decellularization. The mixture of basic fibroblast growth factor (bFGF) and Genipin was evenly distributed throughout the ECM. The ECM-G@bFGF exhibited excellent swelling properties, favorable biocompatibility, and no significant cytotoxicity. Through the cross-linking effect of Genipin, the degradation rate of the ECM was effectively reduced, and the release duration of bFGF was significantly prolonged. In vivo experimental results further indicated that ECM-G@bFGF could promote faster regeneration of nerve axons, mitigate gastrocnemius denervation-induced atrophy, restore sciatic nerve conduction function, and enhance the recovery of hind limb functionality.

Conclusion: The experimental results regarding the slow release of growth factors from ECM-G@bFGF demonstrated that ECM derived from different tissues could facilitate the release of growth factors from various sources via Genipin cross-linking.

This study presents an eco-friendly approach for synthesizing silver nanoparticles (AgNPs) using olive cake hydrolysate (OCH), produced through microbial fermentation of olive cake waste by Pseudomonas fluorescens. The OCH was analyzed by gas chromatography-mass spectrometry (GC-MS), revealing the biotransformation of olive cake components into bioactive compounds, including 24-norursa-3,12-diene, methyl esters of 9,12-octadecadienoic acid and 9-octadecenoic acid, and α-sitosterol. The biosynthesized olive cake hydrolysate-silver nanoparticles (OCH-AgNPs) were characterized using ultraviolet-visible (UV-Vis) spectroscopy to confirm surface plasmon resonance at 420 nm; Fourier-transform infrared (FTIR) spectroscopy to identify the involvement of hydroxyl and carbonyl functional groups; X-ray diffraction (XRD) analysis to verify the crystalline structure, revealing prominent (111) lattice planes of face-centered cubic (fcc) silver; transmission electron microscopy (TEM) to assess morphology and particle size, showing spherical nanoparticles with an average diameter of 19.6 ± 6.1 nm; dynamic light scattering (DLS) to measure hydrodynamic diameter, yielding a size of 109.8 nm; and zeta potential analysis to determine surface charge, which indicated high colloidal stability with a zeta potential of - 47.0 mV. OCH-AgNPs exhibited superior antimicrobial activity compared to OCH alone, with low MIC values against P. aeruginosa, Candida albicans, Aspergillus brasiliensis, and Staphylococcus aureus MRSA. Larvicidal activity, optimized via Box-Behnken design, showed 98.86% mortality of Culex pipiens at 1.0 µg/mL (LC₅₀ = 0.40 µg/mL), significantly outperforming OCH (LC₅₀ = 57.22 µg/mL). Histopathological and biochemical analyses of treated larvae revealed structural damage, decreased protein and carbohydrate content, and inhibition of acetylcholinesterase. Cytotoxicity assays on human skin fibroblasts confirmed low toxicity (IC₅₀ >200 µg/mL). Molecular docking identified α-sitosterol as a key bioactive component. These findings underscore the potential of OCH-AgNPs as a sustainable and multifunctional biocontrol agent for microbial and vector management.

Stevia is a potential alternative sweetener for individuals with diabetes. Gamma radiation is one technique that can alter a plant's physiological traits or phytochemical makeup without producing any dangerous byproducts or chemical initiators. Therefore, the aim of the current study was to determine the effect of gamma radiation (0, 3, 5, 7, and 10 kGy) on the bioactive compounds of dry stevia leaves. In comparison to non-irradiated samples, it is clear that all gamma radiation doses raised the percentages of carbohydrates, total steviosides, total sugar, reducing sugar, crude protein, and nitrogen, while decreasing the percentages of fat, ash, and fiber. The irradiation of stevia leaves at a dose of 7 kGy resulted in the most significant increase in carbohydrates by 57.7%, total steviosides by 32.8%, total sugars by 38%, reduced sugars by 66.8%, and crude protein by 21.9% when compared to non-irradiated samples. In contrast, the percentages of fat, ash, and fiber decreased by 23.2%, 10.8%, and 11.9%, respectively. According to the HPLC profile chromatogram, stevia leaves exposed to 3, 5, and 7 kGy had higher concentrations of all identified phenolic compounds than non-irradiated leaves; 5 kGy was outperformed by 3 and 7 kGy, while 10 kGy resulted in a decrease in these compounds. While apigenin and ellagic acid only disappeared from leaves exposed to 10 kGy, kaempferol was seen to disappear from all irradiated leaves. Furthermore, cinnamic acid was detected at radiation doses of 5, 7, and 10 kGy (0.50, 0.90, and 0.14 µg.ml^- 1, respectively), whereas it was absent at the non-irradiated and 3 kGy radiation doses. The Fourier Transform Infrared (FTIR) spectra of the irradiated and non-irradiated stevia samples displayed a comparable band profile. In conclusion, gamma irradiation of dried stevia leaves increased the levels of carbohydrates, steviosides, sugars, crude protein, and phenolic compounds, while reducing the levels of fat, ash, and fiber, with no observable differences in the FTIR spectra between the irradiated and non-irradiated samples. The optimal radiation dose was 7 kGy, which resulted in the most significant enhancement in biologically active compounds, along with the emergence of cinnamic acid.