Current Microbiology最新文献

Chimeric antigen receptor (CAR)-based immunotherapies face significant translational challenges in solid tumor applications, particularly regarding manufacturing scalability, tumor targeting specificity, and antigen heterogeneity. This systematic review evaluates microbial systems as innovative platforms to address these limitations through synthetic biology-driven approaches, with a focus on bridging preclinical advances to clinical implementation. Analysis of 389 peer-reviewed studies (2015-2025) reveals that engineered probiotic strains (e.g., Escherichia coli Nissle 1917) achieve selective tumor colonization while functioning as programmable factories for:1. Synthetic antigen production and single-chain variable fragment (scFv) expression,2. Costimulatory domain delivery enabling antigen-agnostic CAR-T activation,3. Tumor microenvironment modulation via immunostimulatory chemokines. Microbial platforms demonstrate superior manufacturing economics (70-90% cost reduction vs. conventional methods) and enhance CAR-T functionality through epigenetic reprogramming by microbial metabolites (e.g., short-chain fatty acids). CRISPR/Cas-engineered genetic circuits further enable precise spatiotemporal control of therapeutic payloads.Microbial systems represent transformative platforms for scalable, programmable CAR immunotherapy with significant potential for solid tumor targeting. Key barriers to clinical translation include biocontainment challenges, incomplete mechanistic understanding of tumor homing specificity, and safety validation requirements. Strategic integration of synthetic biology with microbial chassis offers a viable pathway toward accessible next-generation cancer therapies.

Talaromyces marneffei (TM), an opportunistic pathogenic fungus, binds to CD86, which acts as a co-stimulatory molecule for CTLA4. CD86 activates CTLA4, which transmits inhibitory signals, yet its role in TM immune responses remains unclear. In this study, we investigated how the binding of TM to CD86 modulates the CD86-CTLA4 regulatory pathway. To establish the co-culture system of THP-1/THP-1-CD86-EGFP, TM, and Jurkat, Jurkat cells were first transfected with lentivirus to generate the target cell lines. The interactions among TM, CD86, and CTLA4 within this system were then investigated using confocal fluorescence microscopy. To evaluate changes in the expression levels of target factors, RT-qPCR and Western blotting were performed. Potential downregulated pathways were further identified through RNA sequencing (RNA-Seq) analysis. Additionally, the functional role of CTLA4 in the co-culture system was assessed by bactericidal assays. In the co-culture system, THP-1 macrophages engulfed TM, which bound to CD86 and formed immature phagosomes that subsequently escaped. Escaped TM interacted with Jurkat cells via CD86, activating CTLA4. Transcriptional levels of CD86 and CTLA4 initially increased and then decreased in the TM(+) vs. TM(-) comparison. After 24 h, OE showed significant differences in CD86 and CTLA4 (transcriptional and translational levels) vs. CON and NC, along with differences in IFN-γ, IL-5, and IL-13. At 48 h, CD86 and CTLA4 expression varied with THP-1/CD86-EGFP presence. RNA-seq showed TM proliferation and differentiation downregulated PI3K-Akt and T cell receptor pathways. The fungal killing assay indicated that CTLA4 may facilitate TM in evading immune-mediated damage. TM regulates the CD86-CTLA4 immune regulatory pathway by binding to the CD86 protein, thereby evading the immune killing of macrophages.

Polyhydroxyalkanoates (PHAs) are synthesized by microorganisms as cytoplasmic biopolymers in response to nutritional starvation. These biopolymers have diverse applications because of their non-toxic and biodegradable nature and can be an effective alternative to conventional petrochemical polymers as they offer similar qualities. For this purpose, PHA-producing bacterium LO1 was isolated from lubricating oil contaminated soil and identified as Bacillus subtilis (MK071733). Furthermore, LO1 was found to be the most prominent PHA accumulating strain on groundnut oil as carbon source under optimized growth conditions. The optimum growth conditions for PHA synthesis was pH 7, temperature 35 °C, incubation period 72 h, inoculum size 4%, (v/v), groundnut oil 2%, (v/v), and ammonium sulfate 1.5%, (w/v) in mineral salt medium (MSM). Under these optimized conditions, 5.52 g/L of PHA cell dry weight (CDW) was obtained from 9.8 g/L of bacterial dry cell weight (DCW) through two-stage shake flask cultivation. Further, extracted PHA was characterized via Fourier transform infrared spectroscopy (FT-IR) and Gas chromatography-mass spectrometry (GC-MS). These techniques confirmed the presence of mcl-PHA copolymers in the extracted polymer.

Drug-resistant tuberculosis (DR-TB), resulting from newly emerging strains of Mycobacterium tuberculosis (Mtb), and the World Health Organisation (WHO) included it as a top-priority antimicrobial-resistant pathogen. Whole genome sequence analysis (WGS) of clinical Mtb isolates could correlate to their drug resistance phenotype and may also reflect their metabolome. In this report, clinical Mtb isolates (S1, S4, S5, S6, S7, S10) harvested from the sputum of tuberculosis patients were characterized using drug sensitive test (DST), electron microscope, WGS and untargeted Gas chromatography and mass spectrometry (GC-MS) based metabolomics analysis. The majority of these Mtb isolates showed similar size (length: 1.0-3.2 μm; width: 0.32-0.52 μm) to the H37Rv Mtb strain, whereas significant variations were observed in their growth kinetics, WGS and metabolome profiles. In-silico drug resistance prediction, from the WGS data (single-nucleotide polymorphisms (SNP) pattern) of these Mtb isolates, showed resistance to tuberculosis drugs and matched with DST results. Differences in the genes involved in stress response, pathogenicity, and drug efflux pumps were observed between isolates, but genes of the central carbon metabolic pathways and amino acid metabolism were conserved. GC-MS-based metabolite profiling of these clinical isolates identified 291 metabolites involved in various metabolic pathways, and a subset of these metabolites (glutamic acid, aspartic acid and serine) contributed to the drug resistance patterns. These clinical Mtb isolates could be useful as an alternate reagent for understanding host-pathogen interaction. The pipeline used for WGS analysis could be used to predict the drug resistance pattern of new Mtb isolates.

Fusarium head blight (FHB), primarily caused by Fusarium graminearum, leads to severe contamination of wheat grains with the mycotoxin deoxynivalenol (DON), posing a significant threat to grain safety and quality. While chemical control remains common, its efficacy is increasingly challenged by fungicide resistance and potential stimulation of DON production. Biological control represents a promising alternative, yet the identification of effective antagonistic agents and elucidation of their mechanisms are still needed. This study evaluated the biocontrol potential of the endophytic bacterium Bacillus velezensis strain 6W1 against FHB and DON contamination. The crude antagonistic extract exhibited a clear dose-dependent inhibitory effect on the mycelial growth of F. graminearum. The EC₅₀ value was determined to be 210.79 µg/mL, and complete growth inhibition (100%) was achieved when the extract concentration reached 800 µg/mL. Likewise, DON biosynthesis was significantly suppressed in a concentration-dependent manner, with DON levels reduced to 0 at 800 µg/mL of the crude extract.Furthermore, macrolactin A was identified as the core antagonistic compound responsible for the observed antifungal activity. A field trial confirmed that strain 6W1 application significantly reduced FHB severity and DON accumulation in wheat grains. These findings demonstrate the potential of B. velezensis 6W1 as an effective biocontrol agent against FHB and provide a theoretical basis for its application in managing DON contamination.

Endophytic fungi represent promising sources of bioactive compounds with therapeutic potential. The biological effects of ethyl acetate extracts from two endophytic fungi (Aspergillus fumigatus and Pleosporales) isolated from Terminalia phanerophlebia root and bark tissues were examined in this study. Antimicrobial efficacy was evaluated using disc diffusion, minimum inhibitory concentration (MIC), and bactericidal/fungicidal assays against human pathogens. Both extracts demonstrated significant activity against multidrug-resistant Staphylococcus aureus (MRSA), with A. fumigatus showing superior potency (MIC: 15.6 µg/mL) and Pleosporales, 62.5 µg/mL. Antioxidant properties were assessed via 2,2-diphenyl-1-picrylhydrazy (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assays, revealing dose-dependent activity with IC₅₀ values of 167.39 and 132.33 µg/mL for A. fumigatus, and 209.69 and 174.20 µg/mL for Pleosporales, respectively. Preliminary cytotoxic effects were measured using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a tetrazole) assay on breast cancer (MCF-7), hepatocellular carcinoma (HepG2), and normal kidney (HEK 293) cells. Both extracts exhibited selective cytotoxicity against cancer cells with minimal effects on normal cells. Apoptotic induction was confirmed through ethidium bromide/acridine orange staining. Chemical profiling via gas chromatography-mass spectroscopy (GC-MS) and Fourier transform infrared (FT-IR) spectroscopy identified bioactive compounds, including pyrrolo[1,2-a]pyrazine derivatives, phenolic compounds, and ascorbic acid esters. These findings highlight the therapeutic potential of endophytic fungi from T. phanerophlebia as a source of antimicrobial, antioxidant, and potential anticancer agents. However, further investigations are needed to establish these findings in clinical studies.