Current Research in Biotechnology最新文献

Hexavalent chromium or Cr(VI) is highly toxic for humans as it causes high oxidative reactions inside cells, leading to diseases like chronic ulcers and damage to the kidneys, mucous membranes, throat, skin, and respiratory tract. Due to rapid urbanization, Cr(VI) comes into our food chain through unmonitored and uncontrolled application in agriculture fields, refineries, mills, the tanning industry, automobiles, road works, etc. Presently, the standard Cr(VI) detection is done using conventional processes, which, though accurate, has severe drawbacks in on-the-spot rapid detection in the field. Here, we have represented a handheld potentiostat towards trace-level Cr(VI) detection in aquatic environments. A Cr(VI) specific DNA aptamer immobilized screen printed electrode (SPE) has been used as the main biosensor. The device operates on an electronic peak current dumping event through mass deposition in the presence of an aptamer coupled with Cr(VI) onto the working electrode. The working range of the developed prototype is in the range of 0–1000 ppb Cr(VI), where the maximum linearity has been observed in the range of 0–500 ppb with a limit of Detection (LOD) as low as 10 ppb. The device has exhibited an excellent correlation with commercially available electrochemical workstations with a coefficient of 0.972. Moreover, the applicability of the developed device has been validated for 7 different types of water samples. To our knowledge, this is the first-ever reported simplistic resource-limited on-spot aptasensing device for Cr(VI) detection in an aquatic environment.

Chemically, microplastics (MPs) are synthetic materials composed of plastic monomers and additives and vary in size from 0.1-5,000 μm. Due to their chemical stability and the widespread use of plastics for various purposes, MPs pollution of the environment has increased dramatically, leading to the contamination of daily consumer products as well. Although previous studies have reported the environmental impacts of MPs, only a few studies have highlighted the occurrence of MPs in food products and their possible effects on human health. Recent investigations have identified MP particles in drinking water and other beverages, seafood, plant products, salt, sugar, and honey, raising an alarm over the safety and quality of these food items. Ingestion, inhalation, and dermal contact of such food and other consumer goods are the common routes through which MPs may enter the human body and can have several deleterious health impacts including oxidative stress, inflammation, immunotoxicity, increased risk of neoplasia, cellular metabolism impairment, neurotoxicity, gut microbiome dysbiosis, disruption of reproductive system among others. A collective approach employing source control, recycling, biodegradable plastics, strengthening legislation, and bioremediation could be a promising and sustainable solution to control the MPs pollution. The key challenge appears to standarize detection methods along with reducing the MPs contamination from the food products as well as from the environment. Therefore, this review focuses on the occurrence of MPs in several food products, current methods of analysis, potential health impacts, and strategies to mitigate the widespread MPs pollution. It also adds novel findings, knowledge gaps, and recommendations that can guide future research in this field.

Microalgae are widely used in wastewater treatment because they can absorb nitrogen and phosphorus pollutions and reduce CO₂ emissions. However, they are hard to collected due to tiny cell sizes. Flocculation of microalgae by fungi to form the algal-mycelial pellets (AMPs) is one of the efficient collecting methods from wastewater. With the large amount of saline wastewater being discharged, the flocculating effects and mechanisms of AMPs in high saline wastewater are still unknown. Flocculation experiments were performed by Aspergillus niger and Chlorella sp. to study the effects and mechanisms in 0 %-4% salinities. Results showed that the flocculating efficiency (FE) in the 0 %–2% salinities exceeded 95 % at 24 h, whereas the FE reached only 63 % ± 2 % in the 4 % salinity. The flocculating biomass were also decreased with the increasing salinity. Fungi pellets increased in volume and mass at high salinity, resulting in a more compact mycelium structure with less space for microalgae to attach, which was not conducive to flocculation. Furthermore, contents of proteins (PN) and polysaccharides (PS) in the tightly bound EPS (TB-EPS) of AMPs at 4 % salinity decreased by 44 % ± 8 % and 33 % ± 4 % respectively compared to those at 0 % salinity. The decrease in the content of PN and PS led to a weakening of hydrophobicity, a rise in electrostatic repulsion, and an increase in the energy barrier of AMPs, all of which impeded flocculation. This study will provide theoretical bases for the treatment and the recovery of microalgae in high saline wastewater.

Although Serratia marcescens is known for its natural ability to produce the red pigment prodigiosin, it has been little explored as a biocatalyst in bioelectrochemical systems (BES). Here, we have employed an environmental S. marcescens isolate S734 as biocatalyst in a microbial fuel cell (MFC) anode to oxidize glycerol and to produce energy; we have evaluated how the anode behaves in three conditions: (i) as an abiotic electrode (FC-A); (ii) as a biotic electrode after S. marcescens biofilm growth (MFC-B); and (iii) as an abiotic electrode added with the supernatant containing prodigiosin (FC-P). Scanning electron microscopy and electrochemical measurements indicated that prodigiosin formed a conductive film over FC-P, which increased charge transfer by 424 times compared to FC-A. The maximum power density during the FC-P operation was 10.0 mW/m⁻². Nevertheless, only in the presence of S. marcescens (MFC-B) was glycerol oxidized and electricity generated. Cyclic voltammetry indicated that the prodigiosin was the electrochemical active substance in the supernatant, and that its process was irreversible and controlled by adsorption. Electrochemical impedance spectroscopy confirmed that the prodigiosin-containing supernatant decreased the load resistance from 8396.3 Ω in FC-A to 58.10 Ω in FC-P. Genomic analysis showed that the prodigiosin biosynthesis gene cluster in strain S734 belonged to the Serratia 274 type, which contains pigA to pigN genes flanked by cueR and copA homologues. In conclusion, the supernatant produced by S. marcescens strain S734, containing prodigiosin could be explored as a green conductor in BES without further purification steps.

Synthetic biology greatly accelerated the building process of potential microbial cell factories for the production of industrially relevant compounds, e.g., chitooligosaccharides (COS) which have an enormous application potential in multiple industries, i.e., pharma, cosmetics and agrifood. COS are produced by the heterologous expression of the chitin oligosaccharide synthase, NodC, in Escherichia coli, mainly yielding mixtures of chitintetraose (A4) and/or chitinpentaose (A5). We rationalised here product formation limitations based on molecular modelling of the structures of several NodC enzymes. We used this information to protein engineer NodC, rendering longer COS. Hence, an in vivo platform of defined COS-producing strains with different degrees of polymerisation was developed and experimentally characterised. Significantly, several strains were producing long COS, such as chitinhexaose (A6) and −heptaose (A7), not identified in any other natural producer. Additionally, other engineered strains efficiently produce almost 100% specific A4 or A5 product. Altogether, our results indicate that electrostatics-driven dynamics effects are to be considered in the molecular ruler hypothesis. Charge density at the transmembrane helices of NodC affects the opening of the integral binding pocket and in this way the length of the produced chitin oligomers can be modulated. As a result, the internal ruler mechanism elaborated and validated in this manuscript can serve as a guideline to perform site-directed mutagenesis at positions in related NodC and chitin synthase enzymes for both industrial applications as for identification of therapeutic targets.

The production of biopeptides from food waste through microbial fermentation faces challenges arising from the diverse proteolytic abilities of microorganisms and substrate variability, impacting both the quality and yield of generated biopeptides. To address these challenges, preliminary in-silico bioinformatics analyses play a crucial role in evaluating suitable substrates and proteases for the fermentation process. However, existing tools lack comprehensive predictive capabilities for relevant proteases, substrate performance assessment, and final biopeptide family characterization. To overcome these limitations, we developed FEEDS (Food wastE biopEptiDe claSsifier), a novel biopeptide prediction and classification tool. FEEDS predicts biopeptide families based on microbial genome protease profiles and substrate composition during proteolysis. The tool also employs a machine learning approach for functional biopeptide classification. Results from testing on 1000 microbial genomes demonstrate the effectiveness of biopeptide classification, particularly in categorizing peptides derived from substrates like Hordeum vulgare and Vitis vinifera seed storage proteins. In addition to biopeptide classification, our study delves into the distinctive protease profiles of bacteria and yeast genomes. Bacterial genomes exhibited 60 to 100 proteases across 40–55 families. Contrastingly, yeast genomes displayed a more evenly distributed pattern with 150 to 160 protease-encoding genes across 60 to 67 families, surpassing bacterial counts. Remarkably, a substantial portion of yeast proteases (∼66 %) was secreted. Moreover, our integration of a machine learning methodology within the FEEDS pipeline proved highly effective, achieving over 80 % accuracy in predicting the function of peptides derived from seed storage proteins. Notably, longer peptide sequences exceeding 20 amino acids consistently displayed a higher probability of correct assignment compared to shorter counterparts.

PDHα1 gene encodes catalytic subunit PDHE1α of pyruvate dehydrogenase (PDH) complex. Based on previous studies, it is hypothesized that inhibition of PDH activity prevents the entry of glycolytic pyruvate into TCA cycle, while promotes fatty acid oxidation and reduces liver triglyceride (TG) level, thereby alleviating nonalcoholic fatty liver disease (NAFLD). In this study, an in vitro model for NAFLD was established with medical fat emulsion; the most effective siRNA for PDHα1 gene was screened out by qPCR technology; the alterations in metabolism of glucose and lipid, and structure & function of mitochondria in the NAFLD cells were primarily evaluated after transfecting PDHα1 siRNA. As the results showed, after inhibiting the expression of PDHα1 gene, glucose level in culture medium was time-dependently increased, and LDH activity in the cells was moderately elevated after 24 h of transfection and then returned to the normal level after 48 h; intracellular TG level was decreased while LPS activity was increased in a time-dependent manner; no significant change in mitochondrial structure was observed with or without siRNA transfection, and ATP content was obviously reduced after 24 h of transfection, followed by restoration after 48 h. It can be concluded that inhibiting PDHα1 gene in fatty liver cells enhances lipid degradation, and represses the utilization of glucose to an extent, thus reducing TG level without impacting energy generation required for cell survival.

Since millions of cancer-related deaths and diagnoses exist yearly, malignant tumors are a primary worldwide health concern. A promising method for treating cancer is tumor immunotherapy, which focuses on neoantigens. Neoantigens are tumor-specific antigens expressed on cancer cells due to genetic changes, viral infections, or other biological processes. They serve as excellent immune system targets to identify and attack cancerous cells. Neoantigens are more immunogenic than tumor-associated antigens (TAAs) because they lack central tolerance. Successful clinical trials of neoantigen-based vaccines have raised interest in individualized tumor immunotherapy. Furthermore, neoantigens represent a significant advancement in cancer immunotherapy, offering the potential for personalized and effective tumor treatments. The identification, synthesis, and application of neoantigen-based vaccines hold promise for improving patient outcomes and revolutionizing cancer treatment approaches. This review focuses on the significance of neoantigens in cancer immunotherapy, their classification and identification, the synthesis of neoantigen vaccines, clinical trials and the principles underlying their therapeutic efficacy.

Wood-degrading white-rot fungi can efficiently degrade all plant biomass components, but the molecular mechanisms behind the degradation of plant polysaccharides remain poorly understood. For example, the gene sets and expression levels induced by the plant polysaccharide-derived monosaccharides in white-rot fungi do not reflect those induced by crude plant biomass substrates. To explore the molecular response of the white-rot fungus Dichomitus squalens to plant-derived oligo- and polysaccharides, we investigated the transcriptomes from mono- and dikaryotic strains of the fungus on 10 substrates and compared the expression of carbohydrate-active enzyme-encoding genes to that previously reported for different monosaccharides and cellobiose. Our results revealed that in D. squalens, a robust response to cellulose leads to its effective depolymerization, with an orthologue of the ascomycete Trichoderma reesei ACE3 likely acting as a central transcriptional regulator. The conserved response between cellulose and cellobiose further confirms cellobiose as the main cellulase inducer in D. squalens. Surprisingly, despite low abundance of pectin in the natural wood substrate of D. squalens, we identified polygalacturonic acid as a major inducer of a broad-targeted pectinolytic response including pectinase, pectin-related sugar transporter and catabolism genes, and four fungal specific transcription factors. This indicates that D. squalens has not only maintained its ability to degrade minor polysaccharide components in its biotope, but also a regulatory system spanning from extracellular degradation to metabolic conversion. Our study contributes to a deeper understanding of the molecular mechanisms behind white-rot fungal plant polysaccharide degradation and provides leads for functional studies of potential transcriptional regulators in basidiomycetes.