Electronic Journal of Biotechnology最新文献

Background

Juglone is a naphthoquinone currently obtained by chemical synthesis with biological activities including antitumor activity. Additionally, juglone is present in the green husk of walnut, which suggests evaluating the effect of GH extracts on carcinogenic cell lines.

Results

Walnut green husk ethanolic extract was obtained as 169.1 mg juglone/100 g Green Husk and antioxidant activity (ORAC) of 44,920 μmol Trolox Equivalent/100 g DW Green Husk. At 1 μM juglone in HL-60 cell culture, green husk extract showed an antiproliferative effect, but pure juglone did not; under these conditions, normal fibroblast cells were not affected. A dose-dependent effect on mitochondrial membrane potential loss was observed. Apoptosis of HL-60 was detected at 10 μM juglone. Despite high ORAC values, neither purified juglone nor the extract showed protective effects on HL-60 cells under oxidative conditions.

Conclusions

Green husk extract generates an antiproliferative effect in HL-60 cells, which is related to an induction of the early stages of apoptosis and a loss of mitochondrial membrane potential. The normal cells were not affected when juglone is present at concentrations of 1 μM, while at higher concentrations, there is loss of viability of both cancerous and healthy cells.

How to cite: Soto-Maldonado C, Vergara-Castro M, Jara-Quezada J, et al. Interactive 360° video to: Polyphenolic extracts of walnut (Juglans regia) green husk containing juglone inhibit the growth of HL-60 cells and induce apoptosis. Electron J Biotechnol 2022;57. https://doi.org/10.1016/j.ejbt.2022.04.002.

Background

Foods including probiotics are considered “functional foods.” As an alternative to dairy products, we investigated the behavior of Lactobacillus casei when exposed to low-pH fruit juice. Juices of fruits such as pineapple, raspberry, and orange were assessed. Free and microencapsulated forms of L. casei were compared, and the viability of the probiotic was evaluated under storage at 4°C for 28 d. Microbiological analyses were carried out to ensure a safe and healthy product for consumers who look for foods with probiotics from sources other than dairy.

Results

Low pH affected L. casei survival during storage depending on the type of fruit juice. In the case of pineapple juice, some microcapsules were broken, but microcapsules recovered at the end of the storage period had 100% viability (2.3 × 10⁷ CFU/g spheres). In the case of orange juice, more than 91% viability (5.5 × 10⁶ CFU/g spheres) was found. In raspberry juice, viability decreased rapidly, disappearing at the end of the storage period, which was caused by the absorption of high concentrations of anthocyanin inside microcapsules more than low pH.

Conclusions

Low pH affected the survival of L. casei under refrigeration; even when they were microencapsulated, acidic conditions impacted their viability. Although pH affects viability, its value is very sensitive and will depend on the type of fruit juice and its composition. Some fruit juices contain compounds used as substrates for Lactobacillus and other compounds with antimicrobial effects.

How to cite: Olivares A, Soto C, Caballero E, et al. Interactive 360° video to “Survival of microencapsulated Lactobacillus casei (prepared by vibration technology) in fruit juice during cold storage”. Electron J Biotechnol 2022;57. https://doi.org/10.1016/j.ejbt.2022.04.003.

Background

With a smaller environmental footprint and longer operation times, Microbial Fuel Cells (MFCs) are now preferred over other renewable technologies for powering small electronic devices in the field. Although with excellent performance in the laboratory, most of MFCs fail for not considering the real field conditions. The purpose of this study is the development of a compact, portable, and self-sustaining format of energy production based on MFC technologies. For this, three MFC configurations, soil MFC, plant MFC and a hybrid-MFC, where a plant and a soil MFC are combined, are assembled in portable power devices and compared.

Results

Plant MFCs provided lower performances (maximum power of 0.6 ± 0.4 µW·cm⁻²) resulting from a fast and sharp decrease in the anode potential by the flowing of oxygen from the aerenchyma of the plant roots. The performance of soil MFCs was much better (maximum power of 2.0 ± 0.02 µW·cm⁻²), but not sustained over time (20 days) by the depletion of organic matter. The combination of a soil MFC and a plant in separate compartments of a single container results in a hybrid-MFC with a good performance (maximum power of 2.7 µW·cm⁻²) which sustained over time for more than 1 month.

Conclusions

Therefore, the hybrid self-containing MFCs appears as an ideal alternative for the long-term power supply of low-power field electronic devices, from meteorological sensors or LED lights.

How to cite: Uria-Molto N, Costa RD, Nunziata C, et al. Self-contained and integral microbial fuel cells as portable and sustainable energy sources for low-power field devices. Electron J Biotechnol 2022;57. https://doi.org/10.1016/j.ejbt.2022.04.004

Background

In view of the increasing human life and the aging of the population, the search for safe anti-aging drugs has become a hot topic. Agaricus blazei Murrill is a rare edible fungus, with a variety of biological activities. The purpose of this study was to clarify the anti-aging effect and mechanism of ABM-A on the aging induced by D-Galactose in mice.

Results

The result showed that ABM-A contained 87.2% of glucose, 3.3% of galactose, 3.8% mannose and 5.7% gluconic acid. The behavior of mice in the treatment group was significantly improved after administration of ABM-A. And the activity of SOD and CAT and the level of T-AOC were increased (p < 0.05), the content of MDA and ROS was decreased (p < 0.05) in the serum of mice in ABM-A group. The results of mechanism research showed that nine genes were screened out by functional annotation and enrichment analysis for the verification by RT-qPCR, and the results of RT-qPCR were consistent with those of RNA-seq. Western Blot results showed that ABM-A upregulated the expression of Hmox1, Myd88, p-c-Jun, Apc, Bmil, Cox7a2l and Ndufv1, down-regulated the expression of Nfe2l2, Keap1, Apoe, Mapk1and Atp1a3, and decreased the phosphorylation of p38 and Jnk, suggesting that it may play an anti-aging effect by regulating Nrf2/ARE and MAPKs superfamily signal pathways.

Conclusions

ABM-A can reduce oxidation reaction and play an anti-aging role through Keap1-Nrf2/ARE and MAPKs signaling pathway.

How to cite: Guo, X, Ye Y, Liu X, et al. Effects of Agaricus blazei acidic polysaccharide on the aging of mice through keap1-Nrf2/ARE and MAPKs signal pathway. Electron J Biotechnol 2022;57. https://doi.org/10.1016/j.ejbt.2022.03.004

Background

Polyhydroxybutyrate (PHB) and polyhydroxybutyrate-co-hydroxyvalerate (PHBV) are the most common polyhydroxyalkanoates (PHAs). They are important candidates for biodegradable plastics that accumulate in the cytoplasm in the form of intracellular granules under unbalanced growth conditions. The present study focused on the production and optimization of PHAs from Paraburkholderia sp. PFN29 for the first time under submerged fermentation.

Results

Two hundred bacterial isolates were collected from soil samples in Thailand, six of which were found to accumulate PHB using the Nile red staining method. Six isolates were identified by 16S rDNA gene sequencing and were shown to be closely related to the genera Azotobacter, Sphingobium and Paraburkholderia. The best strain, Paraburkholderia sp. PFN29, showed the highest PHB concentration (5 ± 0.17 g/L). Optimization of PHB accumulation was achieved in modified medium containing 3% (w/v) glucose, and 0.1% (w/v) (NH₄)₂Fe(SO₄) with incubation at pH 7.0 and 35°C for 96 h with shaking at 200 rpm. In preliminary PHBV synthesis, PFN29 was utilized to synthesize PHBV from glucose and organic acids (levulinic acid and propionic acid). ¹H nuclear magnetic resonance (¹H NMR) spectroscopy and gas chromatography-mass spectrometry (GC/MS) analyses confirmed the extracted PHAs compared to standard PHB and PHBV.

Conclusions

PFN29 can be used for feasible PHB production with a PHB content of up to 97.3% of 5.14 ± 0.17 g/L CDW. The PHBV concentration can be further improved by optimizing the production parameters as cosubstrates. The present study provides useful data on PHA production by Paraburkholderia, which may be used as a candidate species for commercial PHA production.

How to cite

Sriyapai T, Chuarung T, Kimbara K, et al. Production and optimization of polyhydroxyalkanoates (PHAs) from Paraburkholderia sp. PFN 29 under submerged fermentation. Electron J Biotechnol 2022;56. https://doi.org/10.1016/j.ejbt.2021.12.003

Background

In the process of recombinant protein biosynthesis affinity tags are efficient tools to achieve the expected purity and yield during the purification steps. Nonetheless these tags might alter enzyme specificity and activity, therefore in functional assays it is recommended to use authentic or native proteins. Several ubiquitin fusion systems have been developed for E. coli-based recombinant protein expression that provide high levels of expression, with simple purification, and allow the production of various proteins with authentic N-terminus for subsequent applications.

Results

In the present research, we describe an ubiquitin fused bacterial biosynthetic system (pUbiq) for the production of the native Second mitochondria-derived activator of caspases (SMAC) recombinant protein. Using this system, the recombinant protein is expressed with an ubiquitin-decahistidine fusion partner, then purified from the cell-forming proteins by affinity chromatography. The fusion partner is then removed by proteolytic digestion, resulting the native structure of the recombinant protein without unnecessary amino acid residues. Following proteolysis, another affinity chromatography method is used to separate the native protein from the fusion partner and the proteolytic enzyme. The folding of the protein of interest was verified by a pull-down assay.

Conclusions

Based on our results, the presented pUbiq system was successfully applied in the production of native SMAC recombinant protein, where the affinity tag required for purification was completely removed. Our study suggests that the ubiquitin-fusion technology will be useful for enhancing expression and purification of native and authentic proteins for structural and functional studies as well as for therapeutic uses.

How to cite: Salamona P, Orbána CK, Molnár-Nagy K, et al. Exon based amplified polymorphism (EBAP): A novel and universal molecular marker for plants. Electron J Biotechnol 2022;56. https://doi.org/10.1016/j.ejbt.2022.01.002.

Background

In solvent-producing Clostridium species, several physiological conditions and morphological forms can be observed during batch ABE fermentation. Currently, the contribution made by each condition or form to the production of acids and solvents is not clear. Flow cytometry and fluorescence microscopy have been used to analyze the presence of different morphological and physiological conditions for Clostridium species; however, there are few studies to quantify their contribution to fermentation kinetics.

Results

Morphological changes of the batch cultures of Clostridium beijerinckii NCIMB-8052 were followed by flow cytometry and epifluorescence microscopy. Three cell types were identified, and the percentage of each one was estimated along the culture, showing that they are present throughout the culture and its population distribution was in agreement with the kinetics of growth and acids and solvents production. Yields for the global population and for each subpopulation were estimated. The values of the yield for butanol and acetone based on the fraction of solventogenic cells were 2.5 times the values of the parameters obtained for the whole biomass, while those for acetic and butyric acids based on the acidogenic cell type was 1.5 times.

Conclusions

Quantitative analysis of the subpopulations by flow cytometry allows the calculation of the yields related to specific cell types, isolating the contribution of each subpopulation to the production of acids and solvents.

How to cite: Paredes I, Quintero J, Guerrero K, et al. Kinetics of ABE fermentation considering the different phenotypes present in a batch culture of Clostridium beijerinckii NCIMB-8052. Electron J Biotechnol 2022;56. https://doi.org/10.1016/j.ejbt.2021.12.002

Background

Infusions of Maiten (Maytenus boaria) leaves are used in folk medicine as an antipyretic and for skin allergic rash treatment. Antioxidant, antipyretic and anti-inflammatory properties of medicinal plants have been attributed to phenolic compounds presence. This work, the first in this type, reports the presence of total phenolic compounds (TPC), total flavonoids (TFC), and the antioxidant activity by DPPH, FRAP and ORAC methods of extracts of maiten leaves, including an infusion; also, antimicrobial activity on Gram + and Gram − bacteria were determined. In addition, the presence of Quercetin and catalase were determined, and the FTIR spectrum was done.

Results

The best values of TPC and TFC were 20.55 g_GAE/kg_leaves, and 23.69 g_QE/kg_leaves, respectively, in an ethanolic extract. Best antioxidant activities were obtained in a methanolic extract for DPPH, aqueous extract for FRAP. No significant differences were observed in ORAC activity determination of aqueous, ethanolic, and methanolic extracts and a maiten infusion, with an average value of 22.41 mmol_TE/kg_leaves. In the case of antimicrobial activity, extract of maiten leaves can inhibit the growth of bacteria as Escherichia coli and Listeria monocytogenes, among others.

Conclusions

M. boaria leaves are an important source of phenolics compounds with antioxidant activity; these properties are observed in extracts and infusions. In addition, the extract of maiten leaves produces the inhibition of pathogens Gram+ and Gram− bacteria, showing the great therapeutic potential of this plant used in folk medicine.

How to cite: Soto-Maldonado C, Fernández-Araya B, Saavedra-Sánchez V. Antioxidant and antimicrobial capacity of Maytenus boaria leaves, recovery by infusion and solvent extraction. Electron J Biotechnol 2022;56. https://doi.org/10.1016/j.ejbt.2022.02.002.

Background

Proliferation of bacteria, such as Staphylococcus aureus and Staphylococcus epidermidis, on orthopedic implants has been a challenge in orthopedic surgery, highlighting the problem of the increasing antibiotic resistance and the necessity to develop new antimicrobial agents. In this sense, antimicrobial peptides are promising candidates, which can be attached to titanium surfaces in order to make them safer. Mytilus mussels are characterized by adhering efficiently to a wide variety of surfaces, especially metallic ones, through adhesive proteins with a high content of dihydroxyphenylalanine, which is a post-translational modification of tyrosine.

Results

This work refers to the synthesis of a coating based on a bifunctional peptide that combines a sequence derived from the mussel foot protein-5 and the antimicrobial peptide pEM-2, derived from Bothrops asper snake venom. The adhesive properties of this bifunctional peptide were evaluated, as well as the adhesive sequence without the pEM-2, using a Quartz Crystal Microbalance. The results showed that the presence of the antimicrobial peptide improved the adhesion; however, a loss of the bactericidal activity was observed. Even so, the adhesive sequence by itself exhibited an important antifouling activity, preventing S. aureus and S. epidermidis adhesion to titanium by 75% and 45%, respectively, although the result against S. epidermidis was not significant.

Conclusions

A 13-residue peptide derived from a natural and biocompatible source, like a Mytilus mussel adhesive protein, could be projected as a protective agent on titanium surfaces against S. aureus and S. epidermidis, being responsible for two thirds of the cases of orthopedic implant infection.

How to cite: Gauna A, Mercado L, Guzmán F. Antimicrobial characterization of a titanium coating derived from mussel-glue and Bothrops asper snake venom for the prevention of implant-associated infections caused by Staphylococcus. Electron J Biotechnol 2022;56. https://doi.org/10.1016/j.ejbt.2022.02.001.

Background

Vibrio natriegens is a Gram-negative bacterium that offers a greater metabolic capacity than Escherichia coli for the production of recombinant proteins. This potential includes a low minimum doubling time of 7 min and a high maximum glucose uptake rate of 3.9 g*g⁻¹*h⁻¹. We therefore tested the ability of V. natriegens to produce the insect metalloprotease inhibitor (IMPI), an antimicrobial peptide, fused to the glucosamine-binding protein A (GbpA) secretion/purification tag, using the Vmax Express system.

Results

The IMPI-GbpA fusion protein was secreted into the medium and could be purified directly from the fermentation supernatant by affinity chromatography, including on-column digestion with thrombin. We also modified the GbpA tag by deleting the second and third domains, which reduced the size of the tag while maintaining its functionality. This modification also increased the IMPI yield.

Conclusions

The use of V. natriegens as an expression platform and GbpA for protein secretion and purification facilitates the inexpensive production of antimicrobial peptides. Our process achieved a higher volumetric yield than earlier attempts to produce recombinant IMPI in E. coli. However, the accumulation of IMPI causes V. natriegens growth arrest before the carbon source is depleted, suggesting it may be possible to achieve even greater productivity by further process optimization.

How to cite: Schwarz S, Gerlach D, Fan R, et al. GbpA as a secretion and affinity purification tag for an antimicrobial peptide produced in Vibrio natriegens. Electron J Biotechnol 2022;56. https://doi.org/10.1016/j.ejbt.2022.01.003.