Electronic Journal of Biotechnology最新文献

Background

Camels are known for their survival under harsh and nutrient-deficient climates. Camel rumen ecosystem presents a unique opportunity to study the ruminal microbes helping the camel in this task. The genus Aspergillus is the extensively studied filamentous fungus due to its ability to secret industrially important enzymes. The present study was aimed to isolate and characterize microbes with lignocellulolytic capacity from camel rumen.

Results

The fungal isolate Aspergillus sydowii C6d, isolated from camel rumen, was sequenced and analysed for its CAZyme content responsible for lignocellulose degradation. The C6d isolate was evaluated for its capacity to produce cellulase, pectinase, xylanase, and amylase with their respective assays and further evaluated for their optimum pH. The genome sequencing and assembly resulted in 32.27 Mb of genome size with a GC % of 50.59. The CAZyme analysis revealed that the C6d produced 543 polysaccharide-degrading CAZymes amongst which, 148 CAZymes were potentially involved in lignocellulose degradation. The genomic comparison of the C6d with 30 commonly used lignocellulolytic fungi (white rot, brown rot, and soft rot fungus) showed the enrichment of cellulolytic and pectinolytic CAZymes in C6d genome as compared to others. The saccharification of lignocellulosic substrate wheat straw resulted in the release of 50.85% of reducing sugars.

Conclusions

The study provides important insights into the CAZymes responsible for lignocellulolytic ability in the novel fungus Aspergillus sydowii C6d isolated from camel rumen and presents a valuable source of CAZymes to be further evaluated for potential biotechnological applications.

How to cite: Tulsani NJ, Jakhesara SJ, Hinsu AT, et al. Genome analysis and CAZy repertoire of a novel fungus Aspergillus sydowii C6d with lignocellulolytic ability isolated from camel rumen. Electron J Biotechnol 2022;59. https://doi.org/10.1016/j.ejbt.2022.06.004.

Background

Diverse plants respond differently to similar saline conditions. The aim of the current study was to determine the variation in the foliar contents of phenolic compounds, carotenoids, and proline, and the variation of the activities of catalase (CAT) and superoxide dismutase (SOD) of the edible and medicinal Physalis ixocarpa throughout three different times of exposure (24, 42, and 57 d) to three salinity levels (0, 90, and 120 mM NaCl). The specific effects of salt concentration and time of exposure were also assessed.

Results

Proline increase was the only clearly salt-related response, evidencing its significant protective role in salinized P. ixocarpa under either short, medium, or chronic exposure. One phenolic acid, which increased up to 26.26 times its concentration (compared to control, under high salinity at the longest treatment) out of the eight compounds forming the phenolic profile of the species, and CAT and SOD, under 90 and 120 mM NaCl, respectively, and short and medium exposure, also made important contributions. Salt concentration mainly affected total phenolics, tannins, phenolic acids (PA), proline, and SOD, whereas exposure time mainly affected flavonoids, carotenoids, and CAT.

Conclusions

The participation of the different protection mechanisms of P. ixocarpa against salinity is dynamic and complementary, and it is differentially modulated by the salt concentration and the time of exposure. Proline is the main mechanism for the species. The accurate chronic registration of the responses is needed to determine its adaptation potential to salt stress. The results have agronomic and food quality implications.

How to cite: Hernández-Pacheco CE, Almaraz-Abarca N, Marlon Rojas-López M, et al. Salinity generates varying chemical and biochemical responses in Physalis ixocarpa (Solanaceae) during different times of exposure. Electron J Biotechnol 2022;59. https://doi.org/10.1016/j.ejbt.2022.06.002

Background

Protected agriculture (PA) is an alternative allowing the control of environmental variables to produce healthy vegetables. Biofertilizers and biofungicides can reduce the chemical load of pesticides. There is abundant literature documenting individual aspects, such as control of environmental variables, irrigation, biological control, and cost assessments. However, there are no reports documenting integral approaches in which variables are considered altogether in a successful case study of mid-tech technology, suitable in middle-income countries like México. We tested if mid-tech greenhouses using biocontrol and biofertilization can increase profits, using tomato as a model system. This work provides considerations about middle-income countries’ agriculture and the need for a multidisciplinary approach to offer cost-effective, sustainable alternatives to producers.

Results

This technology yielded up to 254 tons/ha·year of tomato, achieving reductions of 44–60% in water consumption, 25% in chemical nitrogen-fertilization, and 28% in the cost unit of production, increasing the profits by ∼45% in relation to Mexican conventional greenhouses management.

Conclusions

This case study has shown that it is possible to significantly increase profits in mid-tech greenhouse tomato production by increasing productivity and crop quality and decreasing the use of water and agrochemicals through greenhouse automatization, crop management, and beneficial bacteria applied to crops. This manuscript includes a video, supplementary to the main contributions of the project. Please visit this URL: https://youtu.be/uRBGgJqfkLE.

How to cite: Serrano-Carreón L, Aranda-Ocampo S, Balderas-Ruíz KA, et al. A case study of a profitable mid-tech greenhouse for the sustainable production of tomato, using a biofertilizer and a biofungicide. Electron J Biotechnol 2022;59. https://doi.org/10.1016/j.ejbt.2022.06.003.

Background

Bacterial cells often harbor multiple plasmids, but the interaction between these plasmids is poorly understood. Pseudomonas putida ND6, one of the typical naphthalene-degrading bacteria, contains two annotated plasmids, pND6-1 and pND6-2. The conjugative plasmid pND6-2 can be used as a helper to mobilize the naphthalene-degrading plasmid pND6-1. The role of pND6-1 in functions other than naphthalene degradation has never been explored. Therefore, it is of great significance to study the possible effect of pND6-1 on the transfer rate or maintenance of pND6-2.

Results

To investigate the interaction between pND6-1 and pND6-2, we successfully cured plasmid pND6-1 using the incompatibility method, generated the pND6-1-null strain ND6dp1, and first classified it into the IncP-7 group by curing experimental evidence. Subsequently, the pND6-1-cured mutant showed an insignificant increase in cell growth compared with the wild ND6, indicating that a lower cost was imposed on the host by pND6-1. The influences of pND6-1 on the stability and conjugation of plasmid pND6-2 were subsequently explored. The results showed that the presence of pND6-1 enhanced the stability of pND6-2 in natural host ND6 and heterologous host P. putida KT2440. In addition, the presence of pND6-1 in wild-type hosts promoted intra-specific and inter-specific conjugative transfer efficiency of pND6-2 by 3.9–6.3-fold with P. putida, P. resinovans, and P. fluorescens as the recipients, respectively.

Conclusions

Collectively, these results suggest that the plasmid pND6-1 improves the pND6-2 plasmid's stability and transfer rate in the ND6 strain with the selected recipient strains.

How to cite: Wang S, Liu M, Wang D, et al. Plasmid pND6-1 enhances the stability and conjugative transfer of co-resident companion plasmid pND6-2 in the naphthalene-degradative Pseudomonas putida strain ND6. Electron J Biotechnol 2022;59. https://doi.org/10.1016/j.ejbt.2022.08.002.

Background

Endosomally produced by eukaryotic cells, exosomes are microvesicles involved in cell-to-cell communication. Exosomes have shown a wide range of therapeutic potential as a drug or vaccine delivery system, and they are useful as biomarkers in several disease processes. Another biological function described is pathogen dissemination through host-derived molecules released during infection, thus modulating the immune response in the host.

Results

This work characterizes the exosomal fraction recovered from serum of Piscirickttesia salmonis-challenged Salmo salar specimens and from the corresponding non-challenged controls. Exosomes presented a spherical morphology and particle size distribution within 50–125 nm, showing similar parameters in both groups. The mass spectrometry analysis of exosomes isolated at 14 and 21 d post-challenge showed the presence of peptides corresponding to the three proteins of Hsp70/DnaK chaperone system (DnaK, DnaJ, and GrpE). BLAST search of these peptides showed the specificity to P. salmonis. Data are available via ProteomeXchange with identifier PXD023594.

Conclusions

The chaperones were found with >95% identity in the core genome when aligned to 73 genomes of P. salmonis. The proteins also showed a high degree of similarity with other microorganisms, where this system has proven to be vital for their survival under stress conditions.

The presence of these three proteins in exosomes isolated from challenged fish sera calls for further study into their potential role in bacterium pathogenicity.

How to cite: Muñoz C, Carmona M, Luna O, et al. Serum-isolated exosomes from Piscirickettsia salmonis-infected Salmo salar specimens enclose bacterial DnaK, DnaJ and GrpE chaperones. Electron J Biotechnol 2022;59. https://doi.org/10.1016/j.ejbt.2022.07.003.

Background

The temperature upshift has been widely used as an induction system to produce recombinant proteins (RPs). However, thermoinduction could affect bacterial metabolism, RP production, and RP aggregation. Understanding the structure and functionality of those aggregates, known as inclusion bodies (IBs), is a research area of interest in bioprocesses being scarcely studied under thermoinduction. Here, we describe the effect of the thermoinduction (39°C or 42°C) on the production of the recombinant human granulocyte–macrophage colony-stimulating factor (rHuGM-CSF) using Escherichia coli W3110 under the system λpL/cI857.

Results

Results indicated that at 39°C, the production of biomass was almost doubled as well as the acetate accumulation compared to 42°C. Cultures thermoinduced at 42°C improved 1.5-fold the total protein over biomass yield and 1.25-fold the RP over total protein yield. Furthermore, 42°C accelerated the onset of IB formation, changing its architecture. Additionally, IBs formed at 42°C were less soluble and presented higher disorderly structures compared with IBs formed at 39°C, enriched in α-helix and amyloidal-like structures.

Conclusions

This study highlights the observation that IBs attain different architecture in response to small changes in environmental conditions, such as the induction temperature, being this helpful information to improve thermoinduced bioprocesses.

How to cite: Restrepo-Pineda S, Rosiles-Becerril D, Vargas-Castillo AB, et al. Induction temperature impacts the structure of recombinant HuGM-CSF inclusion bodies in thermoinducible E. coli. Electron J Biotechnol 2022;59. https://doi.org/10.1016/j.ejbt.2022.08.004.

Background

Hair follicle development is important for the fineness of wool. Our previous methylated DNA immunoprecipitation sequencing showed that IGFBP2 and IGFBP4 were differentially methylated at different development stages of the hair follicle of Super Merino sheep. This study selected these two genes as candidates to uncover the influence of their promoter methylation on hair follicle development.

Results

The results showed that the expression levels of IGFBP2 and IGFBP4 in the skin of very fine wool Super Merino sheep were higher than that in the very thick wool group, and the difference for IGFBP4 was significant. The total methylation rate of IGFBP2 promoter was extremely low, and no significant difference was found in the skin tissue of the Super Merino sheep at different fineness groups. However, the total methylation rate of IGFBP4 promoter in the very thick group was significantly higher than that in the very fine group, and the total DNA methylation levels of the IGFBP4 were significantly negatively correlated with mRNA expression. Furthermore, the transcription factor prediction results showed 104 and 91 candidate binding sites for transcription factors in the promoter regions of IGFBP2 and IGFBP4, respectively. Among these, JUN, EP300, SP1, PAX6, ETS1, and MYOD1 may be related to hair follicle development.

Conclusions

The total methylation level of IGFBP4 promoter was negatively correlated with its mRNA expression in Super Merino sheep skin tissues with different degrees of fineness, which could be used as an epigenetic marker for wool breeding in Super Merino sheep.

How to cite: Tian Y, Du J, Yang X, et al. Sheep IGFBP2 and IGFBP4 promoter methylation regulates gene expression and hair follicle development. Electron J Biotechnol 2022;59. https://doi.org/10.1016/j.ejbt.2022.07.001.

Background

Antifreezing activity is a phenomenon of great significance in food industry that affects the quality of frozen foods. As a solution, ice-binding proteins, more specifically antifreeze proteins, have been used to mitigate recrystallization. However, knowledge about the mechanism of ice recrystallization and the influence of antifreeze proteins is scarce.

Results

In this work, model homopeptides of three amino acids (proline, arginine and lysine) were studied by means of differential scanning calorimetry through the determination of their thermal hysteresis activity, to see the influence of several factors on their secondary structure. It was found that model homopeptides formed polyproline II type secondary structure that was more stable at low temperature. In addition, thermal hysteresis activity was higher for peptides of intermediate lengths and for proline homopeptides.

Conclusions

The study of homopeptides sheds light on the mechanism of antifreeze activity and will allow the design of new molecules with antifreeze properties to be used in diverse biotechnological fields.

How to cite: Rojas R, Aróstica M, Carvajal-Rondanelli P, et al. Relationship between type II polyproline helix secondary structure and thermal hysteresis activity of short homopeptides. Electron J Biotechnol 2022;59. https://doi.org/10.1016/j.ejbt.2022.08.003.

Background

Cellulose is one of the most abundant natural sources of carbon. In biofuel manufacturing, cellulase is used as an enzyme to hydrolyze cellulose into a fermentable product (glucose). Pseudomonas stutzeri is one of the microorganisms found in cattle rumen. The microbiome of the rumen is heterogeneous and known for its potentiality to efficiently hydrolyze cellulose. Recent studies have identified, cloned, and crystallized one of the cellulase genes present in P. stutzeri, the A1501 cellulase gene (PST_2494 gene).

Results

This study describes the isolation of cellulase-producing bacteria from sheep's rumen. The highest cellulase-producing isolate was identified as P. stutzeri by 16s rDNA sequencing. qRT-PCR was used to measure the cellulase gene expression levels, revealing a higher gene expression of the PST_1459 gene (4 folds) compared to PST_2494 genes. Moreover, cellulase productivity was enhanced by UV irradiation mutagenesis.

Conclusions

Sheep's rumen bacterial isolates were tested for their cellulase productivity, and the highest was identified as P. stutzeri. An investigation of the cellulase genes of P. stutzeri revealed the presence of an unidentified cellulase gene (PST_1459). A qRT-PCR reaction was carried out to validate and measure the expression levels of different cellulase genes, revealing a higher gene expression of the PST_1459 gene than PST_2494 genes. Moreover, UV irradiation mutagenesis was performed to enhance cellulase productivity. The gene expression tested by qRT-PCR confirmed the enhancement of cellulase productivity in some of the mutants obtained.

How to cite: Al Makishah NH, Elfarash AE. Molecular characterization of cellulase genes in Pseudomonas stutzeri. Electron J Biotechnol 2022;59. https://doi.org/10.1016/j.ejbt.2022.07.004.

Background

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder globally, and is often caused by abnormal fatty acid metabolism. Plant-based fatty acid may lower the risk of NAFLD, but evidence shows that plant-based fatty acid can still induce fatty liver. Lignosus rhinoceros is a mushroom that is widely used as folk medicine in Southeast Asia. Studies indicate that L. rhinoceros can act as an antioxidant and immune modulator, might be a potent modulator for NAFLD. In this study, a plant-based high-fat diet (HFD) was used to induce fatty liver in hamsters. Hot water extract of L. rhinoceros was applied during the induction period. The antioxidant capacity of L. rhinoceros was evaluated.

Results

Data reveal that L. rhinoceros extract had promising DPPH scavenging and ferrous ion chelating compacities. The total phenolic and flavonoid contents were 366.23 ± 5.06 mg gallic acid and 28.67 ± 2.5 mg rutin equivalents per gram of raw L. rhinocerus powder, respectively. Lignosus rhinoceros extract lowered body weight, and reduced liver damage which was induced by HFD in hamster, possibly by reducing mononuclear cell infiltration in the liver. Lignosus rhinoceros treatment also lowered the cholesterol content and improved the HDL-c/LDL-c level in hamster serum. Finally, L. rhinoceros reduced the reactive oxygen species content in the liver which was caused by HFD.

Conclusions

This investigation provides evidence that a plant-based HFD may be a risk factor in fatty liver. It also proves that L. rhinoceros promotes liver health, and so can be used in functional food.

How to cite: Tsai W-C, Hoe T-L, Lu S-C, et al. Lignosus rhinocerus attenuates non-alcoholic fatty liver induced by plant-based high-fat diet in hamster. Electron J Biotechnol 2022;58. https://doi.org/10.1016/j.ejbt.2022.05.004.