Frontiers in bioscience (Elite edition)最新文献

A rise in population and societal changes have increased pressure on resources required to meet the growing demand for food and changing dietary preferences. The increasing demand for animal protein is concerning and raises questions regarding sustainability due to its environmental impact. Subsequently, scientists seek alternative proteins, such as microbial proteins (MPs), as an environmentally friendly choice. The production of MPs promotes benefits, including reducing deforestation and CO₂ emissions. Several microorganism types, such as bacteria, yeast, fungi, and algae, use a variety of substrates for MP production, from agricultural residues to lignocellulosic biomass. These complex substrates, including lignocellulosic biomass, are converted to fermentable sugar through either chemical, physical, or biological methods. Indeed, fermentation can occur through submerged cultures or other methods. However, this depends on the substrate and microorganisms being utilized. MPs have properties that make them versatile and useful ingredients in various applications. Using residues and lignocellulosic biomass as raw materials for producing MPs offers sustainability, cost-effectiveness, and waste reduction advantages. These properties are consistent with the principles established by green chemistry, which aims to conserve resources effectively and operate sustainably in all areas. This review highlights the importance of studying manufacturing aspects and the characteristics associated with MPs, which can be implemented to solve problems and encourage novel methods in the global food/feed industry.

Background: Actinobacteria are major producers of antibacterial and antifungal metabolites and are growing their search for substances of biotechnological interest, especially for use in agriculture, among other applications. The Amazon is potentially rich in actinobacteria; however, almost no research studies exist. Thus, we present a study of the occurrence and antifungal potential of actinobacteria from the rhizosphere of Inga edulis, a native South American plant and one that is economically useful in the whole of the Amazon.

Methods: Among the 64 actinobacteria strains isolated from the rhizosphere of three Inga edulis plants, 20 strains were selected and submitted to dual-culture assays against five important phytopathogenic fungi and morphological and 16S rRNA gene analyses. Two strains, LaBMicrA B270 and B280, were also studied for production curves of metabolic extracts and antifungal activities, including their minimum inhibitory concentration (MIC) against phytopathogenic fungi.

Results: Among the 20 strains, 90% were identified as Streptomyces and 10% as Kitasatospora. All the strains showed antagonisms against two or more of five phytopathogens: Corynespora cassiicola, Colletotrichum guaranicola, Colletotrichum sp., Pestalotiopsis sp., and Sclerotium coffeicola. Streptomyces spp. strains LaBMicrA B270 and B280 were active against phytopathogens of the guarana plant (Paullinia cupana). Furthermore, AcOEt/2-propanol 9:1 extract from the 10-day strain LaBMicrA B280 cultured medium presented activity against all the phytopathogens tested, with a minimum inhibitory concentration of 125 μg/mL.

Conclusions: The results revealed various actinomycetes in three rhizospheres of I. edulis in the Amazon and the high potential of metabolic extracts from some of these bacterial strains against phytopathogenic fungi that destroy numerous crops.

Background: Escherichia coli (E. coli) is the most prominent bacterial pathogen that causes urinary tract infections (UTIs), and the rate of resistance to most used antibiotics is alarmingly increasing.

Methods: This study assessed the hostel gutters of two Nigerian universities, the University of Nigeria, Nsukka (UNN) and Kogi State University, Anyigba (KSU), for E. coli and its antimicrobial resistance genes (ARGs). Oxoid Chromogenic UTI agar was used to isolate uropathogenic E. coli (UPEC), identified using standard biochemical tests. The virulence and resistance genes of the isolates were further characterized using molecular techniques.

Results: A total of 906 UPEC were isolated in this study, of which 63 isolates were selected for antimicrobial susceptibility tests. The UPEC isolates showed 100% resistance to amoxicillin/clavulanic acid, vancomycin, and penicillin G, while a complete sensitivity of the isolates to meropenem and ciprofloxacin was observed. The index of isolates showing multidrug resistance ranged from 0.33 to 0.73. The level of multiple drug resistance (MDR) exhibited by the UPEC isolates from effluent was significantly higher compared to those from influent (p < 0.05). The ARGs detected were blaOXA-1 8 (38.1%), blaCTX-M3 8 (38.1%), and ant(2)-la 20 (95.2%). Virulence genes encodings beta-glucuronidase (uidA) and hemolysin A (hlyA) were detected in 95.2% of UPEC isolates.

Conclusion: The current study showed that UPEC is widely distributed in the environment of two Nigerian universities. The index range of MDR and the circulation of ARGs and virulence genes in the environment suggest a potential health concern, thus warranting further investigation.

Since infections associated with microbial communities threaten human health, research is increasingly focusing on the development of biofilms and strategies to combat them. Bacterial communities may include bacteria of one or several species. Therefore, examining all the microbes and identifying individual community bacteria responsible for the infectious process is important. Rapid and accurate detection of bacterial pathogens is paramount in healthcare, food safety, and environmental monitoring. Here, we analyze biofilm composition and describe the main groups of pathogens whose presence in a microbial community leads to infection (Staphylococcus aureus, Enterococcus spp., Cutibacterium spp., bacteria of the HACEK, etc.). Particular attention is paid to bacterial communities that can lead to the development of device-associated infections, damage, and disruption of the normal functioning of medical devices, such as cardiovascular implants, biliary stents, neurological, orthopedic, urological and penile implants, etc. Special consideration is given to tissue-located bacterial biofilms in the oral cavity, lungs and lower respiratory tract, upper respiratory tract, middle ear, cardiovascular system, skeletal system, wound surface, and urogenital system. We also describe methods used to analyze the bacterial composition in biofilms, such as microbiologically testing, staining, microcolony formation, cellular and extracellular biofilm components, and other methods. Finally, we present ways to reduce the incidence of biofilm-caused infections.

Background: Flavonoids are among the most important compounds found in plants, since laboratory studies have shown them to be a daily requirement in human diets due to their various health benefits. Therefore, this study focused on extracting, purifying, and measuring the antioxidant activity of the flavonoid quercetin, which is widely found in plants and possesses a variety of biological activities, from different plant sources.

Methods: The extraction of quercetin was performed using several methods (chemical, physical, and enzymatic) and several extraction solutions (water, ethanol, and chloroform) from several plants (spinach, dill, Onion Skin, Pistacia eurycarpa, sumac, digalkhasab chemri, and leelwi chemri). The alcoholic extract extracted by chemical method was purified and the content of total flavonoids based on quercetin in all plant extracts was determined using adsorption chromatography on a silica gel column (100-200 mesh), followed by thin layer chromatography (TLC). TLC and high performance liquid chromatography (HPLC) were used to assess the purity of quercetin. The ability of quercetin to capture free radicals using 2,2-diphenyl-1-picrylhydrazyl (DPPH) was compared to that of butylated hydroxytoluene (BHT). Statistical analyses were performed using completely randomized designs (CRD) for factorial experiments, and the least significant difference (LSD) test was used to calculate the significant differences between the averages of the coefficients at the 0.05 probability level.

Results: The alcoholic Pistacia extract extracted by chemical method yielded the highest concentration of quercetin (84.037 mg/g). Furthermore, it was found that quercetin purified from Pistacia possessed strong antioxidant activity, and its antioxidant activity increased with increased concentration.

Conclusions: Pistacia eurycarpa showed the highest quercetin content among the assessed plants. Moreover, solvents played a major role in extracting plant components due to the high polarity of flavonoids. Quercetin purified using a silica gel column demonstrated antioxidant activity.

Background: Amalgamation of metal-tolerant plant growth promoting rhizobacteria (PGPR) with biochar is a promising direction for the development of chemical-free biofertilizers that can mitigate environmental risks, enhance crop productivity and their biological value. The main objective of the work includes the evaluation of the influence of prepared bacterial biofertilizer (BF) on biometric growth parameters as well as physiological and biochemical characteristics of rapeseed (Brassica napus L.) at copper action.

Methods: The prepared BF was based on novel metal tolerant strain of PGPR Buttiauxella sp. EA20 isolated from the rhizosphere of orchid Epipactis atrorubens and birch wood biochar (BC). The pot-scale experiments included six treatments: peat-containing control substrate (CS); CS + 200Cu (200 mg Cu/kg of soil); CS + 5% BC (v/v); CS + 5% BC + 200Cu; CS + 5% BF (v/v); CS + 5% BF + 200Cu.

Results: Single Cu treatment caused the decrease in rapeseed leaf area, shoot and root length, fresh and dry biomass, as well as an increase in water saturation deficit, possibly due to damage of cell membranes by lipid peroxidation. Addition of BF or BC alone mitigated these harmful effects of copper. Application of BF, regardless of Cu addition, increased the rapeseed leaf area (1.6 times on average), plant fresh and dry biomass (2.5 times on average), and photosynthetic pigment content (1.8 times on average). In addition, BF treatment along with Cu enhanced the antioxidant activity of B. napus due to the accumulation of non-enzymatic antioxidants such as carotenoids, free proline and soluble phenolic compounds, including flavonoids. Moreover, plant enrichment with copper and essential macronutrients such as nitrogen, phosphorus and potassium was observed.

Conclusions: The study concludes that application of complex biofertilizer based on metal tolerant PGPR strain Buttiauxella sp. EA20 and birch wood biochar mitigated the harmful effects of copper, enhanced the rapeseed growth and increased its biological value. Future perspective includes evaluation of the potential for using the resulting biofertilizer to improve the growth and biofortification of other crop species.

Background: This study aimed to produce, characterize, and apply a biosurfactant as a bioremediation tool for oil-contaminated coastal environments.

Methods: The biosurfactant was produced in a medium containing 5.0% corn steep liquor and 1.5% residual frying oil by Candida tropicalis (URM 1150) for 144 hours with 200 rpm agitation. The growth curve and production of the biosurfactant were evaluated. The emulsifying properties and stability of the biosurfactant were tested against pH, temperature, and NaCl variations. Toxicity assays were carried out on seeds, the microcrustacean Artemia salina, and the bivalve Anomalocardia brasiliana. Static and kinetic assays were performed, alongside stone washing to assess the removal capacity.

Results: The produced biosurfactant had a surface tension reduction capacity of 70 to 25 mN/m, yielding 7.1 g/L, and a critical micellar concentration (CMC) of 0.4%. During the initial 4-hour cultivation period, the growth curve showed an exponential phase, marked by a constant increase in production. In the final growth stage, biosurfactant production reached its maximum value of 7.1 g/L. After 120 h of cultivation, the maximum biomass output of 9.93 g/L was reached. The biosurfactant was applied in static and kinetic tests with seawater and sand contaminated with oil. The biosurfactant remained stable in the face of the tested variations. The biosurfactant is anionic in nature and showed no toxicity to the microcrustacean Artemia salina, vegetable seeds, or the bivalve Anomalocardia brasiliana, which exhibited 100% survival rates. The biomolecule removed 97% of the contaminated oil on the stone. The biosurfactant proved efficient and biocompatible for the bioremediation of oil derivatives, showing significant removal rates of hydrophobic compounds.

Conclusion: These results indicate that the biosurfactant has great potential for application as a remediation agent to clean up oil spills in coastal environments.

Background: Regenerative endodontics requires an innovative delivery system to release antibiotics/growth factors in a sequential trend. This study focuses on developing/characterizing a thermoresponsive core-shell hydrogel designed for targeted drug delivery in endodontics.

Methods: The core-shell chitosan-alginate microparticles were prepared by electrospraying to deliver bone morphogenic protein-2 for 14 days and transforming growth factor-beta 1 (TGF-β1) for 7-14 days. Methylcellulose (MC) and gelatin were utilized to create the core-shell hydrogel to load a modified triple antibiotic combination (penicillin G/metronidazole/ciprofloxacin (PMC)) and growth factor-loaded microparticles in the shell and the core compartments, respectively. Morphological assessment, core-shell structural analysis, FTIR analysis, rheological analysis, swelling, and degradation rate studies were conducted for characterization. The viability of dental pulp stem cells (DPSCs) upon antibiotic exposure, antibacterial activity, and release studies of PMC and growth factors were investigated. Cellular studies (cell viability, alkaline phosphatase (ALP) activity, osteo/odontoblast gene expression (using Reverse transcription-polymerase chain reaction (RT-PCR)) and in vivo studies (inflammatory response and differentiation potential of the developed hydrogel by subcutaneous implantation in rats via histological examination) were assessed.

Results: The hydrogel showed a porous microstructure with interconnected pores. Core-shell structure analysis confirmed the successful extrusion of the MC hydrogel to the surface. FTIR analysis revealed interactions between MC and gelatin. Rheological analysis indicated time-dependent gel formation, supporting thermosensitivity at 37 °C. Swelling occurred rapidly, and degradation reached 62.42% on day 45. Further, antibiotics exhibited no cytotoxicity on DPSCs. Sequential release of antibiotics and growth factors was observed for up to 5 and 14 d, respectively. The hydrogel showed antibacterial activity. DPSCs exhibited increased proliferation, ALP activity, and odontoblast gene expression. In vivo studies showed that the biocompatible drug-loaded hydrogel exhibited more mineralization than the control.

Conclusions: The developed core-shell hydrogel containing PMC and growth factor-loaded core-shell microparticles provided a versatile and biocompatible platform for sequential drug delivery in regenerative endodontics. The system demonstrates promising characteristics for dentin regeneration, making it a potential candidate for clinical applications.

Background: Contamination with crude oil and hydrocarbons has become a global threat. Such threats have urged us to invent solutions to deal with this dilemma. However, chemical treatment comes with limited benefits. The use of bioremediation proved to be the optimal approach to face this problem since it is cost-effective, time-conserving and may improve the quality of soil and increase its fertility.

Methods: Soil samples were collected from three sites with the highest degree of pollution in Iraq: Al-Latifia, Al-Begei, and Basra. These were the source of novel Streptomyces isolates that could degrade contaminants and be used as a source of nutrients. The isolation principle was the degradation of petroleum in these soils as a carbon source.

Results: The most efficient isolate was obtained from Basra soil, characterized by the highest degree of contamination. The bacterium grows on minimal medium with crude oil, diesel fuel, aromatic, and non-aromatic hydrocarbons as the only source of carbon and showed the ability to reduce a hydrocarbon mixture containing 23 analytes with C8-C40 and C13-C30 representing total crude hydrocarbons effectively and with a high mineralization capability reaching 84%. This isolate was found to produce biosurfactants and reduce surface tension significantly.

Conclusions: Using chemical treatment of crude oil contaminants, burying the contaminated areas, or sometimes flooding them with water to eliminate these contaminants may not be an effective solution. Thus, using nonpathogenic microorganisms, especially those indigenous to the soil, maybe the most effective solution to achieve this goal.