Microbial Biotechnology最新文献

Streptomyces genus produces a large number of antibiotics, which are always synthesized by specific biosynthetic gene clusters (BGCs). To resist autotoxicity, transporters encoded by genes located within BGC occasionally pump antibiotic along with transporter encoded by gene located outside BGC. Daunorubicin is an anthracycline antibiotic biosynthesized by Streptomyces species, playing a crucial role in the treatment of leukaemia. In existing studies, only one two-component ATP-binding cassette (ABC) transporter, encoded by drrA1-drrB1 (abbreviated as drrAB1) and located within the daunorubicin BGC, has been proven to extrude daunorubicin. In this work, two other two-component ABC transporters, encoded by drrAB2 and drrAB3 and located outside the cluster, were found to play the complementary role in daunorubicin efflux in S. coeruleorubidus. Disruption of three drrABs resulted in a 94% decrease in daunorubicin production. Furthermore, drrAB2 is regulated by the TetR family regulator DrrR1, responding to the intracellular accumulation of daunorubicin and suggesting its role in stress response and self-resistance. Although the homologues of DrrAB1 are only found in three anthracycline BGCs, the homologues of DrrAB2 and DrrAB3 are spread in many Streptomyces strains which do not contain any known anthracycline BGC. This indicates that DrrAB2 and DrrAB3 may recognize and extrude a broader range of substrates besides daunorubicin, thus playing a more extensive role in cellular detoxification.

In Komagataella phaffii (Pichia pastoris), formate is a recognized alternative inducer to methanol for expression systems based on the AOX1 promoter (pAOX1). By disrupting the formate dehydrogenase encoding FDH1 gene, we converted such a system into a self-induced one, as adding any inducer in the culture medium is no longer requested for pAOX1 induction. In cells, formate is generated from serine through the THF-C1 metabolism, and it cannot be converted into carbon dioxide in a FdhKO strain. Under non-repressive culture conditions, such as on sorbitol, the intracellular formate generated from the THF-C1 metabolism is sufficient to induce pAOX1 and initiate protein synthesis. This was evidenced for two model proteins, namely intracellular eGFP and secreted CalB lipase from C. antarctica. Similar protein productivities were obtained for a FdhKO strain on sorbitol and a non-disrupted strain on sorbitol-methanol. Considering a K. Phaffii FdhKO strain as a workhorse for recombinant protein synthesis paves the way for the further development of methanol-free processes in K. phaffii.

Polycystic ovary syndrome (PCOS) is one of the most widespread endocrinopathy affecting women of reproductive age with detrimental effects on life quality and health. Among several mechanisms involved in its aetiopathogenesis, recent studies have also postulated the involvement of the vaginal and intestinal microbiota in the development of this disorder. In this study, an accurate insight into the microbial changes associated with PCOS was performed through a pooled-analysis highlighting that this syndrome is characterized by intestinal and vaginal dysbiosis with a reduction of beneficial microorganisms and a higher proportion of potential pathogens. Based on this observation, we evaluated the ability of a milk-derived protein exerting positive outcomes in the management of PCOS, that is, α-lactalbumin (α-LA), to recover PCOS-related dysbiosis. In vitro experiments revealed that this protein improved the growth performances of members of two health-promoting bacterial genera, that is, Bifidobacterium and Lactobacillus, depleted in both intestinal and vaginal microbiota of PCOS-affected women. In addition, α-LA modulated the taxonomic composition and growth performances of the microbial players of the complex intestinal and vaginal microbiota. Finally, an in vivo pilot study further corroborated these observations. The oral administration of α-LA for 30 days to women with PCOS revealed that this protein may have a role in favouring the growth of health-promoting bacteria yet limiting the proliferation of potential pathogens. Overall, our results could pave the way to the use of α-LA as a valid compound with ‘prebiotic effects’ to limit/restore the PCOS-related intestinal and vaginal dysbiosis.

The emergence of new techniques in both microbial biotechnology and artificial intelligence (AI) is opening up a completely new field for monitoring and sometimes even controlling the evolution of pathogens. However, the now famous generative AI extracts and reorganizes prior knowledge from large datasets, making it poorly suited to making predictions in an unreliable future. In contrast, an unfamiliar perspective can help us identify key issues related to the emergence of new technologies, such as those arising from synthetic biology, whilst revisiting old views of AI or including generative AI as a generator of abduction as a resource. This could enable us to identify dangerous situations that are bound to emerge in the not-too-distant future, and prepare ourselves to anticipate when and where they will occur. Here, we emphasize the fact that amongst the many causes of pathogen outbreaks, often driven by the explosion of the human population, laboratory accidents are a major cause of epidemics. This review, limited to animal pathogens, concludes with a discussion of potential epidemic origins based on unusual organisms or associations of organisms that have rarely been highlighted or studied.

In this research, biogenic selenium nanoparticles were produced by the fungi Yarrowia lipolytica, and the biological activity of its nanoparticles was studied for the first time. The electron microscopy analyses showed the production of nanoparticles were intracellular and the resulting particles were extracted and characterized by XRD, zeta potential, FESEM, EDX, FTIR spectroscopy and DLS. These analyses showed amorphous spherical nanoparticles with an average size of 110 nm and a Zeta potential of −34.51 ± 2.41 mV. Signatures of lipids and proteins were present in the capping layer of biogenic selenium nanoparticles based on FTIR spectra. The antimicrobial properties of test strains showed that Serratia marcescens, Klebsiella pneumonia, Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis were inhibited at concentrations between 160 and 640 μg/mL, while the growth of Candida albicans was hindered by 80 μg/mL of biogenic selenium nanoparticles. At concentrations between 0.5 and 1.5 mg/mL of biogenic selenium nanoparticles inhibited up to 50% of biofilm formation of Klebsiella pneumonia, Acinetobacter baumannii, Staphylococcus aureus and Pseudomonas aeruginosa. Additionally, the concentration of 20–640 μg/mL of these bioSeNPs showed antioxidant activity. Evaluating the cytotoxicity of these nanoparticles on the HUVEC and HepG2 cell lines did not show any significant toxicity within MIC concentrations of SeNPs. This defines that Y. lipolytica synthesized SeNPs have strong potential to be exploited as antimicrobial agents against pathogens of WHO concern.

Phthalic acid esters (PAEs) are synthetic diesters derived from o-phthalic acid, commonly used as plasticizers. These compounds pose significant environmental and health risks due to their ability to leach into the environment and act as endocrine disruptors, carcinogens, and mutagens. Consequently, PAEs are now considered major emerging contaminants and priority pollutants. Microbial degradation, primarily by bacteria and fungi, offers a promising method for PAEs bioremediation. This article highlights the current state of microbial PAEs degradation, focusing on the major bottlenecks and associated challenges. These include the identification of novel and more efficient PAE hydrolases to address the complexity of PAE mixtures in the environment, understanding PAEs uptake mechanisms, characterizing novel o-phthalate degradation pathways, and studying the regulatory network that controls the expression of PAE degradation genes. Future research directions include mitigating the impact of PAEs on health and ecosystems, developing biosensors for monitoring and measuring bioavailable PAEs concentrations, and valorizing these residues into other products of industrial interest, among others.

The efficiency of global crop production is under threat from microbial pathogens which is likely to be worsened by climate change. Major contributors to plant disease are Pseudomonas syringae (P. syringae) pathovars which affect a variety of important crops. This opinion piece focuses on P. syringae pathovars actinidiae and syringae, which affect kiwifruit and stone fruits, respectively. We discuss some of the current control strategies for these pathogens and highlight recent research developments in combined biocontrol agents such as bacteriophages and combinations of bacteriophages with known anti-microbials such as antibiotics and bacteriocins.

DDT (dichlorodiphenyltrichloroethane) is a commonly used insecticide that is recalcitrant and highly stable in the environment. Currently, DDT residue contamination, especially in agricultural soil, is still a concern in many countries, threatening human health and the environment. Among the approaches to resolve such an issue, novel biodegradation-based methods are now preferred to physicochemical methods, due to the sustainability and the effectiveness of the former. In this study, we explored the possibility of building mixed microbial cultures that can offer improved DDT-degrading efficiencies and be more environmentally transilient, based on genome annotation using the KEGG database and prediction of interactions between single strains using the obtained metabolic maps. We then proposed 10 potential DDT-degrading mixed cultures of different strain combinations and evaluated their DDT degradation performances in liquid, semi-solid and solid media. The results demonstrated the superiority of the mixtures over the single strains in terms of degrading DDT, particularly in a semi-solid medium, with up to 40–50% more efficiency. Not only did the mixed cultures degrade DDT more efficiently, but they also adapted to broader spectra of environmental conditions. The three best DDT-degrading and transilient mixtures were selected, and it turned out that their component strains seemed to have more metabolic interactions than those in the other mixtures. Thus, our study demonstrates the effectiveness of exploiting genome-mining techniques and the use of constructed mixed cultures in improving biodegradation.

Wastewater treatment plants are one of the major pathways for microplastics to enter the environment. In general, microplastics are contaminants of global concern that pose risks to ecosystems and human health. Here, we present a proof-of-concept for reduction of microplastic pollution emitted from wastewater treatment plants: delivery of recombinant DNA to bacteria in wastewater to enable degradation of polyethylene terephthalate (PET). Using a broad-host-range conjugative plasmid, we enabled various bacterial species from a municipal wastewater sample to express FAST-PETase, which was released into the extracellular environment. We found that FAST-PETase purified from some transconjugant isolates could degrade about 40% of a 0.25 mm thick commercial PET film within 4 days at 50°C. We then demonstrated partial degradation of a post-consumer PET product over 5–7 days by exposure to conditioned media from isolates. These results have broad implications for addressing the global plastic pollution problem by enabling environmental bacteria to degrade PET.

DNA damage occurs when cells encounter exogenous and endogenous stresses such as long periods of desiccation, ionizing radiation and genotoxic chemicals. Efforts have been made to detect DNA damage in vivo and in vitro to characterize or quantify the damage level. It is well accepted that single-stranded DNA (ssDNA) is one of the important byproducts of DNA damage to trigger the downstream regulation. A recent study has revealed that PprI efficiently recognizes ssDNA and cleaves DdrO at a specific site on the cleavage site region (CSR) loop in the presence of ssDNA, which enables the radiation resistance of Deinococcus. Leveraging this property, we developed a quantitative DNA damage detection method in vitro based on fluorescence resonance energy transfer (FRET). DdrO protein was fused with eYFP and eCFP on the N-terminal and C-terminal respectively, between which the FRET efficiency serves as an indicator of cleavage efficiency as well as the concentration of ssDNA. The standard curve between the concentration of ssDNA and the FRET efficiency was constructed, and application examples were tested, validating the effectiveness of this method.