Journal of microbiology and biotechnology最新文献

Leuconostoc mesenteroides H40 (H40), originally isolated from kimchi, has been shown to exhibit probiotic characteristics and a neuroprotective effect in SH-SY5Y cells. In this study, we investigated the modulatory effects of heat-killed H40 (H-H40) in a scopolamine-induced (1 mg/kg/day) mouse model of cognitive impairment. H-H40 at either 1 × 10⁸ or 1 × 10⁹ CFU/day alleviated scopolamine-induced cognitive impairment in the novel object recognition and Y-maze tests. Neuroinflammatory cytokines, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, inducible NO synthase (iNOS), and cyclooxygenase (COX)-2 were all found to be decreased by H-H40 treatment. Moreover, changes in neurotransmitter levels and synaptic plasticity were further confirmed through measurement of acetylcholinesterase, acetylcholine, choline acetyltransferase, and brain-derived neurotrophic factor (BDNF) levels. H-H40 increased β-secretase levels, but decreased amyloid-β levels. In addition, the antioxidant effects of catalase and GPx were demonstrated. Overall, our results showed that H-H40 exerts positive cognitive effects by anti-inflammatory and antioxidant activities in a mouse model of scopolamine-induced cognitive impairment. H-H40 could be used as a prophylactic functional food for improving cognition.

Zizania latifolia and its bioactive compound tricin have been recognized for their anti-inflammatory, anti-allergic, and anti-aging properties. However, the impact of Z. latifolia extract (ZLE) and tricin on astrocyte dysfunction, particularly related to disruptions in the amyloid β (Aβ) clearance pathway, has not been extensively studied. This research aims to explore the regulatory effects of ZLE and tricin on astroglial dysfunction, utilizing astrocytic differentiated C6 cells (passages 75~85) subjected to Aβ and high-dose insulin, as well as scopolamine-induced mice. Results revealed that ZLE (500 μg/ml) and tricin (1 μg/ml) significantly upregulated the expression of astrocyte proteins GFAP and AQP4, brain-derived neurotrophic factor (BDNF), low-density lipoprotein receptor-related protein 1 (LRP1), and matrix metalloproteinases (MMPs) in C6 cells treated with Aβ and high-dose insulin. Furthermore, oral administration of ZLE (100 and 300 mg/kg) and tricin (0.3 mg/kg) in mice led to an increase in acetylcholine (ACh) levels and upregulation of insulin-degrading enzyme (IDE), LRP1, and MMPs, while reducing the levels of acetylcholinesterase (AChE), Aβ and ApoE4. These findings suggest that ZLE and tricin may ameliorate Aβ and high-dose insulin-induced astrocyte dysfunction in C6 cells and scopolamine-treated mice, potentially through the AQP4/LRP1 pathway.

Clostridium acetobutylicum, a strict gram-positive anaerobe, plays a pivotal role in biotechnological applications, particularly in the biosynthesis of 1,3-propanediol, a critical biofuel component and monomer for bioplastic production. This study introduces C. acetobutylicum DG1, a metabolically engineered strain designed to enhance the 1,3-propanediol pathway. Despite its development, comprehensive metabolic comparisons between the parent and modified strains remain unexplored. Our research addresses this gap by employing gas chromatography coupled with time-of-flight mass spectrometry to delineate the global metabolite landscapes of both strains. Through multivariate statistical analysis such as principal component analysis and hierarchical clustering analysis, we discovered pronounced disparities in their metabolite profiles across the acidogenic and solventogenic phases. Detailed metabolomics investigations underscored significant divergences in amino acid metabolism, fatty acid metabolism, and the tricarboxylic acid cycle. These findings shed light on the metabolic alterations induced by genetic engineering in C. acetobutylicum, offering novel insights into microbial metabolism that could guide future biotechnological innovations.

We present a highly efficient human HEK293-based cell-free protein synthesis (CFPS) system capable of producing up to 300 μg/ml reporter protein. One of the limitations of the CFPS systems with respect to protein yield has been the decline of the protein-synthesizing activity of the system upon prolonged incubation. Though factors contributing to this decline in activity have been investigated in yeast, little is known about the factors in mammalian systems. We find that a rapid depletion of the components of the energy-regeneration system is a major factor behind the decreasing protein-synthesis activity in the HEK293-derived system. In addition, we demonstrate that a functional CFPS system can be prepared from other mammalian cell lines as evidenced by our use of a human neuroblastoma SH-SY5Y-derived CFPS system. We also find that exogenous creatine kinase (CK) is dispensable for the functionality of the energy-regeneration system in HEK293 due to the presence of a sufficiently high endogenous CK activity in an HEK293 cell-free extract.

Various Actinomycete isolates were collected from the microbial germplasm, including Streptomyces rameus KAC3 (PP550146), Streptomyces bangladeshensis KAC4 (PP177363), Streptomyces mutabilis KAC6 (PP177364), Microbacterium arabinogalactanolyticum KAC8 (PP177365), Streptomyces calvus KAC10 (PP177366), Streptomyces werraensis KAC11(PP177366), and Streptomyces gancidicus KAC12 (PP177389). Three consortia formulations were then selected based on their compatibility with plant growth-promoting rhizobacteria (PGPR) properties under laboratory conditions: C₁ consortium (KAC3, KAC10 and KAC11), C₂ (KAC4, KAC8 and KAC10), and C₃ (KAC11 and KAC12). In this study, we explored the use of locally available, cost-effective carrier materials, such as wood ash (NPK ratio: 1.72:0.86:3.6), charcoal (NPK ratio: 0.93:23.68:0.8), eggshell powder, a surfactant agent (SDS + CTAB), and vermi-compost (NPK ratio: 3.5:0.71:0.6). The CFU counts of Actinomycete isolates in the consortia were calculated over six months at different temperatures (28 and 35 ± 2°C) using these low-cost materials. The C₁ consortium showed the highest stability in maintaining viable populations, whereas C₂ and C₃ showed the best performance in the combined-ingredient carrier material. The efficacy of C₁ was monitored using an IoT device and further validated under different temperature conditions for six months. The data showed that temperature variation affected Actinomycete growth, with an optimal viability at 28 ± 2°C. Moreover, increases in temperature led to higher CO₂ levels and decreased moisture and humidity, yet the Actinomycete population remained stable. This highly efficient C₁ consortium formulation is a promising eco-friendly bioinoculant for sustainable agriculture.

The increasing demand for sustainable and eco-friendly energy sources has intensified research into alternative biofuel feedstocks. Microalgae, recognized for their rapid growth and production of high-value products, have emerged as promising candidates for third-generation biofuels. This study evaluates the potential of Protosiphon botryoides KNUA219, a microalga isolated from Dokdo Island, South Korea, as a biodiesel feedstock. Molecular and morphological analyses confirmed its identity, while growth experiments demonstrated its species-specific physiological characteristics, including an optimal pH range of 5-7, limited salinity tolerance, and high biomass productivity. Biochemical analysis revealed significant levels of carbohydrates (30.42 ± 1.65%), proteins (26.18 ± 1.14%), and lipids (14.86 ± 0.33%) in P. botryoides KNUA219, with glucose and galactose as the dominant monosaccharides. Fatty acid methyl ester profiling identified a lipid composition consisting of saturated (20.54%), monounsaturated (19.03%), and polyunsaturated fatty acids (42.65%), with palmitic, oleic, and linolenic acids as key components. Biodiesel quality assessments indicated compliance with critical standards for cetane number and cold filter plugging point, although optimization was required for iodine value and density. Proximate and ultimate analyses revealed favorable energy properties, including a high volatile matter content (88.94 ± 0.33%) and a calorific value of 23.11 ± 0.11 MJ/kg. These findings establish P. botryoides KNUA219 as a promising and sustainable resource for biodiesel production, while highlighting its potential for broader industrial applicability.

Candida auris is a pathogenic fungus associated with high-mortality infections and forms resilient biofilms on various surfaces. In this study, we introduced a novel antifungal strategy against C. auris by integrating an AI-powered protein design tool, ProteinMPNN, with classical molecular dynamics (MD) simulations to design artificial proteins from a miniprotein library. This combined approach accelerated and enhanced the design process, enabling the rapid development of effective miniprotein inhibitors specifically targeting C. auris biofilm formation. The miniproteins developed in this study exhibited potent inhibitory effects on C. auris biofilms, representing a significant advancement in antifungal therapy. Notably, the combined application of these miniproteins enhanced suppression of biofilm formation. These findings highlight not only the strong therapeutic potential of these designed miniproteins but also the power of combining AI-driven protein design with MD simulations to advance biomedical research.

Synthetic biology has garnered significant global interest owing to its diverse applications in bio-based production, biosensing, living therapeutics, and drug delivery. This heightened interest has increased the demand for novel protein synthesis methods and genome-scale assemblies. However, gene assembly from oligomers presents several challenges, including the risk of incorrect assembly between oligomers, self-annealing, and the potential for insertions or deletions resulting from misannealed oligomers. Dsembler (DNA Assembly Designer) is a web-based software application designed to assemble long DNA sequences. It provides a set of oligomers with optimal melting temperatures and GC overlap, which facilitates a commercially available oligomer pool service. By enhancing the accuracy of oligomer design, Dsembler has addressed critical challenges in synthetic biology and supported advancements in genetic engineering and molecular biology.

Live biotherapeutic products, represented by probiotics with disease-mitigating or therapeutic effects, face significant limitations in achieving stable colonization in the gut through oral administration. However, paraprobiotics, which consist of dead or inactivated microbial cells derived from probiotics, can provide comparable health benefits while overcoming the limitations associated with live biotherapeutic products. Therefore, the purpose of this study was to quantitatively compare and analyze the effects of probiotics, which are gaining attention as treatments for inflammatory bowel diseases, and their paraprobiotic counterparts on the alleviation of ulcerative colitis. In in vitro evaluations revealed that the paraprobiotics derived from Lactiplantibacillus plantarum MGEL20154, Latilactobacillus sakei MGEL23040, and Limosilactobacillus reuteri MGEL21001 exhibited equal or significantly enhanced activities in terms of antioxidant properties, anti-inflammatory effects, and barrier integrity enhancement compared to their probiotic counterparts. Furthermore, consistent with in vitro findings, both probiotics and paraprobiotics effectively improved histological scores and reduced myeloperoxidase levels in a DSS-induced ulcerative colitis mouse model. Notably, paraprobiotics derived from L. plantarum MGEL20154 and L. reuteri MGEL21001 demonstrated significantly enhanced efficacy in restoring tight junctions, promoting mucin secretion, and reducing inflammation in colonic lesion tissues compared to their probiotic forms. Our results suggest that these paraprobiotics may serve as more suitable agents for alleviating and treating ulcerative colitis, addressing limitations associated with probiotics, such as low survival rates, instability, antibiotic susceptibility, and the potential induction of excessive inflammatory responses.