Biotechnology and applied biochemistry最新文献

In the present study, the impact of synthesized graphene oxide-coated zinc sulfide nanoparticles (graphene oxide [GO]-zinc sulfide [ZnS] nanoparticles [NPs]) (100, 300, and 450 µg mL^-1) as a novel elicitor was evaluated on different biochemical traits in callus culture of Thymus daenensis Celak under salinity stress (150 mM NaCl) and non-saline (0 mM NaCl) conditions. Elicitation with GO-ZnS NP showed an increasing effect on H₂O₂, enzymatic, and nonenzymatic antioxidant activity under saline and non-saline conditions. The concentration of 100 µg mL^-1 GO-ZnS NPs produced the highest total phenolics content (TPC) (4.67-fold), phenylalanine ammonia-lyase activity (PAL) (9.85-fold), ascorbate peroxidase (APX) (3.07-fold), catalase (CAT) (1.68-fold), and antioxidant activity (Ferric Reducing Antioxidant Power [FRAP] assay) (7.42-fold), compared to the control treatment (non-salinity and non-GO-ZnS NPs). The total flavonoids (TFD) (2.26-fold) and thymol (17.33-fold) contents showed the highest increase under 300 µg mL^-1 GO-ZnS NPs and salinity stress. Parallel with the significant increase in H₂O₂ activity (4.86 µmol g^-1 FW), the antioxidant activity (2,2-diphenyl-1-picrylhydrazyl [DPPH] assay) increased the most (91.42%) under the combined effects of 450 µg mL^-1 GO-ZnS NPs and salinity stress. The results suggest that 100 µg GO-ZnS NPs mL^-1 might be used as a new elicitor to increase the biosynthesis of total phenolics, thymol, and activity of PAL, APX, and CAT in T. daenensis through callus culture under salinity stress.

Food safety is increasingly challenged by Staphylococcus aureus, which causes mastitis and persists in raw milk, exacerbating public health risks. Among 128 samples of raw cow milk from Barak Valley, Northeast India, 30.46% tested positive for S. aureus according to the International Organization for Standardization (ISO)-recommended methods. The spa gene, indicating pathogenic potential, was detected in 51% of the isolates. 16S rRNA gene sequencing confirmed 93%-100% identity with known S. aureus strains, and novel strains were registered in GenBank. In addition to the appearance of 16 vancomycin-resistant strains, 97% were resistant to ampicillin and nalidixic acid, 74.3% exhibited multidrug resistance (MDR), with an MDR index of ≥0.2, and 61.5% were methicillin-resistant (mecA/mecC-positive), all of which are biofilm producers. The qualitative nature of the Congo red agar method likely contributed to the high biofilm development that was observed in 53.8% of the isolates. In contrast, the tissue culture plate (TCP) method identified 33.3% of the strains as strong biofilm producers, which was significantly correlated with the presence of icaAD genes (45%), suggesting that TCP offers a more accurate assessment. The co-occurrence of mecA + mecC (33.3%) and icaA + icaD (18%) indicates advanced resistance and genetic adaptation. Alternative antimicrobials-ZnONPs and honey-demonstrated promising antibacterial effects with average inhibition zones of 18.3 ± 0.58 and 22.3 ± 0.38 mm, respectively, and minimum inhibitory concentrations (MICs) ranging from 15 to 30 mg/mL. A total of 17.9% of the isolates were resistant to honey. All strains of lactic acid bacteria were effective against 97% of the isolates, with Lactobacillus plantarum demonstrating the strongest antimicrobial action (average of 14.1 ± 0.02 mm), indicating potential use in combating biofilm-associated, drug-resistant Staphylococcus aureus.

Honeybees (Apis mellifera L.) are social insects that have importance in both pollination and human health with their hive products. Due to their natural life cycle, worker bees die after a few weeks and are thrown out of the hive. However, dead bees with their bioactive compounds, such as carbohydrates and proteins, could be a precursor for green synthesis of silver nanoparticles. Green nanoparticles obtained through green synthesis are used in a wide range of fields, from the environment to medicine, with their unique properties. In this study, the potential for the use of dead bees in the green synthesis of silver nanoparticles was determined. For this purpose, naturally dead bees that were thrown out of the hive within one day were collected, dried, grounded, extracted, and used in green synthesis of silver nanoparticles. The obtained nanoparticles (MS-AgNPs) were characterized, and it was observed that the MS-AgNPs gave maximum absorbance at 465 nm and their sizes varied between 79 and 91 nm. It was clear that they had good antioxidant and antimicrobial activity. It could be concluded that dead bees could be an excellent biological reducing and capping agent for green synthesis of silver nanoparticles.

Polyhydroxyalkanoates (PHAs) are biodegradable plastics with great environmental and application value, yet high production costs, mainly from carbon sources, hinder their large-scale use. In sludge dewatering by electrochemical treatment followed by press filtration, leachate with rich organic matter is produced and considered a cheap carbon source. This study converted the leachate to volatile fatty acids (VFAs) under anaerobic fermentation at 35°C and pH 5.5. The PHA was produced from a PHA-producing mixed culture acclimated from wastewater sludge. The VFAs were fed to the mixed culture. The highest PHA content was 42% (g/g VSS). The PHA contains 55% of polyhydroxybutyrate (PHB) and 45% of polyhydroxyvalerate (PHV). When the VFAs were generated from the leachate of the sludge treated with the electrochemical process, the PHA content dropped to 17%. With the treatment of the VFAs or leachate, the PHA content was increased. The highest PHA content was up to 35% (g/g VSS). In addition, co-fermentation of VFAs and acetic acid for PHA production has also shown improvement in PHA accumulation. The study provides an alternative method for PHA production and managing the leachate produced from the electrochemical process for sludge dewatering.

This study investigates the physiological and biochemical responses of a newly isolated microalgal strain, Dictyosphaerium sp. AM-2024a, identified through 18S rDNA sequencing, under varying environmental conditions and microplastic (MP) interactions. Optimal growth of strain AM-2024a was achieved at pH 9, with a 3.55% increase in biomass compared to the control. Sodium bicarbonate supplementation at 50 mM significantly enhanced productivity, with biomass increasing by 45.17%, chlorophyll a by 393.56%, and carbohydrates by 146.42%. This is the first report exploring the interaction of this strain with MPs, specifically low-density polyethylene (LDPE), selected for its environmental prevalence and relevance to aquatic pollution. Exposure to LDPE MPs resulted in a concentration-dependent reduction in biomass (up to 13.95% at 50 mg/L), whereas further analysis indicated the strain's ability to utilize LDPE as part of its metabolic processes. Gas chromatography-mass spectrometry (GC-MS) analysis of fatty acid methyl esters (FAMEs) revealed a favorable lipid profile, dominated by C16 and C18 fatty acids, yielding 84.75% FAMEs, underscoring the strain's potential for sustainable biodiesel production. This study highlights Dictyosphaerium sp. AM-2024a as a novel and robust candidate for biofuel applications and pollutant mitigation, providing a foundation for future research into its ecological and industrial applications.

Haloarchaea are extremophilic microorganisms belonging to the Archaea domain that require high salt concentrations to live, thus inhabiting ecosystems like salty ponds, salty marshes, or extremely salty lagoons. They are more abundant and widely distributed worldwide than initially expected. Most of them are grouped into two families: Halobacteriaceae and Haloferacaceae. The extreme conditions under which haloarchaea survive contribute to their metabolic and molecular adaptations that make them good candidates for the design of bioremediation strategies or the use of the cells as cellular factories to produce highly marketable molecules: enzymes, bioplastics, antibiotics, and natural pigments. Within the molecular adaptations of these microorganisms, the production of rare C₅₀ carotenoids like the one called "bacterioruberin" is attracting attention worldwide, due to their biological activities, including antioxidant, antitumoral, immunomodulatory, antilipidemic, and antiglycemic effects. The production of this natural carotenoid contributes to meeting the high demand that the global carotenoid market is experiencing, to replace the use of chemically synthesized pigments with natural colorants/antioxidants. In this work, new advances in the production of these natural carotenoids are described, placing special emphasis on the challenges of their production on a large scale, as well as on their promising applications in cosmetics, pharmaceuticals and food.

This research seeks to identify and verify the prognostic signature of immune-related RNA of papillary thyroid carcinoma (PTC). The Cancer Genome Atlas (TCGA) database provided the PTC samples and clinical data. Using the limma program, differentially expressed mRNAs and lncRNAs (DElncRNAs) were found. A risk score (RS) model was created by using univariate and multivariate Cox regression analyses to find lncRNAs associated with overall survival prognosis. The association between the lncRNA prognostic signature and the invasion of several immune cell subtypes was investigated using the Tumor Immune Estimation Resource (TIMER). To verify the expression of the prognostic signature, RT-PCR was utilized. From TCGA, 491 PTC tumor samples were acquired, comprising 18497 mRNAs and 2525 lncRNAs. There were 138 DElncRNAs and 494 differentially expressed mRNAs. Six DElncRNAs with independent prognoses were then selected from a total of 138 DElncRNAs. According to the TIMER database, the 6-DElncRNA PTC prognostic signature was correlated with the invasion of several immune cell subtypes. The expression patterns of four DElncRNAs matched the database results, according to RT-PCR analysis. Six lncRNAs were found to constitute a predictive characteristic for PTC in this study, and these signatures were connected to the infiltration of different immune cell subtypes. These findings provide a potential basis for the development of diagnostic biomarkers and immunotherapeutic stratification in PTC.

Hydrogen sulfide (H₂S) has emerged as a crucial signaling molecule with profound physiological and pathological roles, sparking interest in its biotechnological production through microbial engineering. The potential applications of microbially produced H₂S in medicine, agriculture, and industry have driven significant research advancements. This review comprehensively examines the latest developments in engineering microbes for H₂S production. Key topics include genetic and metabolic engineering strategies that enhance H₂S biosynthesis, innovative production methods, and practical applications of microbial H₂S. Additionally, we address the technical and biological challenges faced in optimizing H₂S production, such as maintaining microbial viability and ensuring controlled release. The review also explores future directions in the field, emphasizing the need for sustainable and efficient production systems, the potential for scalable industrial applications, and the integration of H₂S-producing microbes in therapeutic and agricultural settings. Overall, this review provides a detailed overview of the current state and future prospects of H₂S production, highlighting its significance in various biotechnological applications.

The glory lily (Gloriosa superba L.) is a medicinally important and endangered plant found in the Western Ghats of Maharashtra, India. It harbors a diverse community of endophytic fungi with immense biotechnological potential. To explore the potential medicinal properties of the endophytes, this study sought to isolate, identify, and assess the bioactivity of endophytic fungi from various plant tissues of G. superba, such as roots, stems, leaves, and flowers. Twenty-one endophytic fungal cultures were isolated and identified with molecular and morphological analyses. Bioactivity assays demonstrated their antimicrobial, antioxidant, and enzyme-inhibitory properties, supported by the production of secondary metabolites, such as alkaloids, phenolics, and others. These findings highlight the potential of G. superba-associated fungal endophytes as a sustainable source of pharmacologically active compounds, reducing the reliance on harvesting the endangered host plant from its wild habitats. While exploring its endophytes for various applications, conservation strategies, including tissue culture propagation and habitat preservation, should be employed to protect wild G. superba populations. This integrated approach would support biodiversity conservation and sustainable utilization of fungal endophytes isolated from this endangered plant species.

The enzymatic hydrolysis of soybean proteins was investigated using four enzymes (alcalase, flavourzyme, neutrase, and papain) in combination with different concentrations of natural deep eutectic solvents (NADESs) and ionic liquids (ILs). The goal was to assess the influence of these alternative green solvents on enzymatic efficiency. First, the hydrolysis kinetics were studied over a period of 240 min, in which the results showed an optimum time of 150 min, allowing high rates of soluble peptides without system saturation. The protein hydrolysis rate (PHR) was used as an indicator of enzymatic efficiency to evaluate the effect of NADESs based on cholinium chloride (ChCl) with hydrogen bond donors (urea, glycerol, lactic acid [Lac], and acetic acid [Ac]) and ILs formed with cholinium-cation and lactate or acetate anions. The results showed that the alcalase presented the highest hydrolysis values in the presence of ChCl:urea, ChCl:glycerol, and [Ch][Lac], in which a strong hydrolytic activity was observed at concentrations of 50% of the solvent. In contrast, solvents with acidic HBDs (ChCl:lactic acid and ChCl:acetic acid) and [Ch][Ac] showed strong inhibitory effects on enzymatic activity. Molecular docking revealed that while acetate directly interacted with Ser221 of alcalase, the nucleophilic residue in the catalytic triad, lactate formed more distributed and less disruptive interactions. Urea showed strong affinity with peripheral residues, preserving enzymatic structure and functionality. These results demonstrate that combining experimental data and molecular docking analysis constitutes a strategic approach for the rational design of green solvents, optimizing their application as cosolvents in biocatalytic reactions.