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Reasonable fertilization management can increase nutrient content and enzyme activity in rhizosphere soil, and even increase soil microbial richness. However, different fertilizers could raise distinct influences on the soil properties, including soil environmental factors (physicochemical properties and enzymatic activities) and microbial community. Here, the effects of two soil amendments (microbial fertilizer and woody peat) on environmental factors and microbial community structure in tobacco rhizosphere soil were evaluated, with the correlations between microbes and environmental factors explored. As the results, microbial fertilizer could effectively alleviate soil acidification, increase available potassium and organic matter contents in soil, and was also beneficial to increase nitrate reductase activity in rhizosphere soil. Fertilizers cause changes in the abundance of certain microbes in the soil. Besides, it was shown that the candidate phyla Gal15, Acidobacterota, Latescibacterota, Mortierellommycota, Basidiomycota, and Rozellomycota in tobacco rhizosphere soil had significant correlation with soil environmental factors. Through the functional analysis of these populations, it can be deduced that the changes in the abundance of certain microorganisms may be an important reason for the differences in environmental factors. All these indicated that the differences of environmental factors in different treatments are closely related to the abundance of some special soil microorganisms. Studying the life activities of these microbes would provide good guidance for exploring the interaction among crops, soil, and microorganisms and improving crop yields.
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Fertilizantes , Solo , Solo/química , Fertilizantes/análise , Nicotiana , Rizosfera , Microbiologia do SoloRESUMO
ß-Elemene is the major component of a traditional Chinese medicine (Rhizoma Curcumae) for cancer treatment, and plant extraction is the major methods currently. Biosynthesis of ß-elemene is a promising and attractive route due to its advantages, including environmentally friendly processes, renewable resources, and sustainable development. In this research, biosynthesis of germacrene A, direct precursor of ß-elemene, in Escherichia coli was successfully performed and 11.99 mg/L germacrene A was obtained. Thereafter, a cobiosynthesis system for germacrene A and lycopene, another kind of isoprenoid, was constructed. Furthermore, the cultivation conditions were optimized. The germacrene A production was increased to the highest level reported to date, 364.26 mg/L, threefold increase to the strain with only germacrene A production. The cobiosynthesis system was suggested to promote the metabolic flux for germacrene A production. This research enabled germacrene A production in E. coli, and it highlights the promoting mechanism of the cobiosynthesis system for two chemicals which are both belonging to isoprenoids. KEY POINTS : ⢠Co-production of germacrene A and lycopene in E. coli. ⢠Promoting mechanism of cobiosynthesis of two isoprenoid compounds in E. coli. ⢠Shake-flask production of germacrene A reached to the highest 364.26 mg/L in E. coli.
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Escherichia coli , Medicina Tradicional Chinesa , Licopeno , Escherichia coli/genéticaRESUMO
A soluble form of EphA7 (sEphA7) has been found to antagonize the role of full-length EphA7 (EphA7-FL) to stabilize the membrane level of the tight junction protein Claudin6 (CLDN6) during Xenopus pronephros development. However, the mechanism underlying this antagonistic effect remains unclear. In this study, we identified Nicalin, a Nicastrin-like protein, as a novel sEphA7-interacting protein using immunoprecipitation (IP)/mass spectrometry (MS). In HEK293 cells, Nicalin interacted with sEphA7 and they predominantly co-localized in the endoplasmic reticulum (ER). Interestingly, Nicalin diminished the protein level of sEphA7 in the membranous fraction but increased that in the insoluble cytoplasmic fraction with a reduced molecular weight, suggesting that Nicalin restricts the entry of sEphA7 into the ER for further modification. sEphA7 probably acted as a chaperone and enhanced the membrane level of EphA7-FL and the formation of EphA7 complex, however, this effect was reversed by Nicalin. Our work suggested that Nicalin limits sEphA7 secretion, thereby preventing the formation of EphA7 complex. These results demonstrated the potential role of Nicalin in regulating EphA7 expression and revealed a potential mechanism underlying the antagonistic effect between sEphA7 and EphA7-FL.
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Claudinas/metabolismo , Glicoproteínas de Membrana/metabolismo , Proteínas de Membrana/metabolismo , Receptor EphA7/metabolismo , Animais , Biotinilação , Membrana Celular/metabolismo , Citoplasma/metabolismo , Retículo Endoplasmático/metabolismo , Células HEK293 , Humanos , Transdução de Sinais , Xenopus , Proteínas de Xenopus/metabolismoRESUMO
Isoprenoids, as the largest group of chemicals in the domains of life, constitute more than 50,000 members. These compounds consist of different numbers of isoprene units (C5H8), by which they are typically classified into hemiterpenoids (C5), monoterpenoids (C10), sesquiterpenoids (C15), diterpenoids (C20), triterpenoids (C30), and tetraterpenoids (C40). In recent years, isoprenoids have been employed as food additives, in the pharmaceutical industry, as advanced biofuels, and so on. To realize the sufficient and efficient production of valuable isoprenoids on an industrial scale, fermentation using engineered microorganisms is a promising strategy compared to traditional plant extraction and chemical synthesis. Due to the advantages of mature genetic manipulation, robustness and applicability to industrial bioprocesses, Saccharomyces cerevisiae has become an attractive microbial host for biochemical production, including that of various isoprenoids. In this review, we summarized the advances in the biosynthesis of isoprenoids in engineered S. cerevisiae over several decades, including synthetic pathway engineering, microbial host engineering, and central carbon pathway engineering. Furthermore, the challenges and corresponding strategies towards improving isoprenoid production in engineered S. cerevisiae were also summarized. Finally, suggestions and directions for isoprenoid production in engineered S. cerevisiae in the future are discussed.
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Sesquiterpenos , Terpenos , Biocombustíveis , Engenharia Metabólica , Saccharomyces cerevisiae/genéticaRESUMO
Receptor tyrosine kinase EphA7 is specifically expressed in otic region in Xenopus early development. However, its role in otocyst development remains unknown. Knockdown of EphA7 by a specific morpholino oligonucleotide (MO) reduced the size of the otocyst and triggered otic epithelial cell extrusion. Interestingly, EphA7 depletion attenuated the membrane level of the tight junction protein Claudin6 (CLDN6). Utilizing the Cldn6 MO, we further confirmed that CLDN6 attenuation also led to otic epithelial cell extrusion. Our work suggested that EphA7 modulates the otic epithelial homeostasis through stabilizing the CLDN6 membrane level.
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Claudinas/genética , Regulação da Expressão Gênica no Desenvolvimento , Receptor EphA7/genética , Proteínas de Xenopus/genética , Xenopus laevis/embriologia , Animais , Técnicas de Silenciamento de Genes , Homeostase , Xenopus laevis/genéticaRESUMO
The purple nonsulfur phototrophic bacterium Rhodopseudomonas palustris strain CGA009 uses the three-carbon dicarboxylic acid malonate as the sole carbon source under phototrophic conditions. However, this bacterium grows extremely slowly on this compound and does not have operons for the two pathways for malonate degradation that have been detected in other bacteria. Many bacteria grow on a spectrum of carbon sources, some of which are classified as poor growth substrates because they support low growth rates. This trait is rarely addressed in the literature, but slow growth is potentially useful in biotechnological applications where it is imperative for bacteria to divert cellular resources to value-added products rather than to growth. This prompted us to explore the genetic and physiological basis for the slow growth of R. palustris with malonate as a carbon source. There are two unlinked genes annotated as encoding a malonyl coenzyme A (malonyl-CoA) synthetase (MatB) and a malonyl-CoA decarboxylase (MatA) in the genome of R. palustris, which we verified as having the predicted functions. Additionally, two tripartite ATP-independent periplasmic transporters (TRAP systems) encoded by rpa2047 to rpa2049 and rpa2541 to rpa2543 were needed for optimal growth on malonate. Most of these genes were expressed constitutively during growth on several carbon sources, including malonate. Our data indicate that R. palustris uses a piecemeal approach to growing on malonate. The data also raise the possibility that this bacterium will evolve to use malonate efficiently if confronted with an appropriate selection pressure.IMPORTANCE There is interest in understanding how bacteria metabolize malonate because this three-carbon dicarboxylic acid can serve as a building block in bioengineering applications to generate useful compounds that have an odd number of carbons. We found that the phototrophic bacterium Rhodopseudomonas palustris grows extremely slowly on malonate. We identified two enzymes and two TRAP transporters involved in the uptake and metabolism of malonate, but some of these elements are apparently not very efficient. R. palustris cells growing with malonate have the potential to be excellent biocatalysts, because cells would be able to divert cellular resources to the production of value-added compounds instead of using them to support rapid growth. In addition, our results suggest that R. palustris is a candidate for directed evolution studies to improve growth on malonate and to observe the kinds of genetic adaptations that occur to make a metabolic pathway operate more efficiently.
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Malonatos/metabolismo , Redes e Vias Metabólicas , Rodopseudomonas/genética , Biodegradação Ambiental , Transporte Biológico , Regulação Bacteriana da Expressão Gênica , Rodopseudomonas/crescimento & desenvolvimento , Rodopseudomonas/metabolismoRESUMO
Lycopene, a potent antioxidant, has been widely used in the fields of pharmaceuticals, nutraceuticals, and cosmetics. However, the production of lycopene extracted from natural sources is far from meeting the demand. Consequently, synthetic biology and metabolic engineering have been employed to develop microbial cell factories for lycopene production. Due to the advantages of rapid growth, complete genetic background, and a reliable genetic operation technique, Escherichia coli has become the preferred host cell for microbial biochemicals production. In this review, the recent advances in biological lycopene production using engineered E. coli strains are summarized: First, modification of the endogenous MEP pathway and introduction of the heterogeneous MVA pathway for lycopene production are outlined. Second, the common challenges and strategies for lycopene biosynthesis are also presented, such as the optimization of other metabolic pathways, modulation of regulatory networks, and optimization of auxiliary carbon sources and the fermentation process. Finally, the future prospects for the improvement of lycopene biosynthesis are also discussed.
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Escherichia coli , Licopeno/metabolismo , Engenharia Metabólica , Redes e Vias Metabólicas , Escherichia coli/genética , Escherichia coli/metabolismo , Ácido Mevalônico/metabolismoRESUMO
Bread wheat (Triticum aestivum, AABBDD) is one of the most widely cultivated and consumed food crops in the world. However, the complex polyploid nature of its genome makes genetic and functional analyses extremely challenging. The A genome, as a basic genome of bread wheat and other polyploid wheats, for example, T. turgidum (AABB), T. timopheevii (AAGG) and T. zhukovskyi (AAGGA(m)A(m)), is central to wheat evolution, domestication and genetic improvement. The progenitor species of the A genome is the diploid wild einkorn wheat T. urartu, which resembles cultivated wheat more extensively than do Aegilops speltoides (the ancestor of the B genome) and Ae. tauschii (the donor of the D genome), especially in the morphology and development of spike and seed. Here we present the generation, assembly and analysis of a whole-genome shotgun draft sequence of the T. urartu genome. We identified protein-coding gene models, performed genome structure analyses and assessed its utility for analysing agronomically important genes and for developing molecular markers. Our T. urartu genome assembly provides a diploid reference for analysis of polyploid wheat genomes and is a valuable resource for the genetic improvement of wheat.
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Genoma de Planta/genética , Triticum/genética , Sequência de Bases , Brachypodium/genética , Produtos Agrícolas/classificação , Produtos Agrícolas/genética , Diploide , Marcadores Genéticos/genética , Dados de Sequência Molecular , Oryza/genética , Filogenia , Sorghum/genética , Sintenia/genética , Triticum/classificação , Zea mays/genéticaRESUMO
The sulfur oxidization (Sox) system is the central sulfur oxidization pathway of phototrophic and chemotrophic sulfur-oxidizing bacteria. Regulation and function of the Sox system in the chemotrophic Paracoccus pantotrophus has been elucidated; however, to date, no information is available on the regulation of this system in the chemolithotrophic Acidithiobacillus caldus, which is widely utilized in bioleaching. We described the novel tspSR-sox-like clusters in A. caldus and other chemolithotrophic sulfur-oxidizing bacteria containing Sox systems. The highly homologous σ54-dependent two-component signaling system (TspS/R), upstream of the sox operons in these novel clusters, was identified by phylogenetic analyses. A typical σ54-dependent promoter, P1, was identified upstream of soxX-I in the sox-I cluster of A. caldus MTH-04. The transcriptional start site (G) and the -12/-24 regions (GC/GG) of P1 were determined by rapid amplification of cDNA ends (5'RACE), and the upstream activator sequences (UASs; TGTCCCAAATGGGACA) were confirmed by electrophoretic mobility shift assays (EMSAs) in vitro and by UAS-probe-plasmids assays in vivo. Sequence analysis of promoter regions in tspSR-sox-like clusters revealed that there were similar σ54-dependent promoters upstream of the soxX genes. Based on our results, we proposed a TspSR-mediated signal transduction and transcriptional regulation pathway for the Sox system in A. caldus. The regulation of σ54-dependent two-component systems (TCSs) for Sox pathways were explained for the first time in A. caldus, A. thiooxidans, T. tepidarius, and T. denitrificans, indicating the significance of modulating the sulfur oxidization in these chemolithotrophic sulfur oxidizers.
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Acidithiobacillus/genética , Regulação Bacteriana da Expressão Gênica , RNA Polimerase Sigma 54/genética , Sequências Reguladoras de Ácido Nucleico/genética , Enxofre/metabolismo , Acidithiobacillus/metabolismo , Sequência de Bases , Ensaio de Desvio de Mobilidade Eletroforética , Oxirredução , Regiões Promotoras Genéticas/genética , Análise de Sequência de DNA , Transdução de Sinais/genética , Ativação Transcricional/genéticaRESUMO
Akkermansia muciniphila is a gram-negative bacterium that colonizes the human gut, making up 3-5% of the human microbiome. A. muciniphila is a promising next-generation probiotic with clinical application prospects. Emerging studies have reported various beneficial effects of A. muciniphila including anti-cancer, delaying aging, reducing inflammation, improving immune function, regulating nervous system function, whereas knowledge on its roles and mechanism in infectious disease is currently unclear. In this review, we summarized the basic characteristics, genome and phenotype diversity, the influence of A. muciniphila and its derived components on infectious diseases, such as sepsis, virus infection, enteric infection, periodontitis and foodborne pathogen induced infections. We also provided updates on mechanisms how A. muciniphila protects intestinal barrier integrity and modulate host immune response. In summary, we believe that A. muciniphila is a promising therapeutic probiotic that may be applied for the treatment of a variety of infectious diseases.
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Klebsiella pneumoniae is a Gram-negative bacterium within the Enterobacteriaceae family that can cause multiple systemic infections, such as respiratory, blood, liver abscesses and urinary systems. Antibiotic resistance is a global health threat and K. pneumoniae warrants special attention due to its resistance to most modern day antibiotics. Biofilm formation is a critical obstruction that enhances the antibiotic resistance of K. pneumoniae. However, knowledge on the molecular mechanisms of biofilm formation and its relation with antibiotic resistance in K. pneumoniae is limited. Understanding the molecular mechanisms of biofilm formation and its correlation with antibiotic resistance is crucial for providing insight for the design of new drugs to control and treat biofilm-related infections. In this review, we summarize recent advances in genes contributing to the biofilm formation of K. pneumoniae, new progress on the relationship between biofilm formation and antibiotic resistance, and new therapeutic strategies targeting biofilms. Finally, we discuss future research directions that target biofilm formation and antibiotic resistance of this priority pathogen.
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Infecções por Klebsiella , Klebsiella pneumoniae , Humanos , Klebsiella pneumoniae/genética , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/microbiologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Resistência Microbiana a Medicamentos , Biofilmes , Testes de Sensibilidade MicrobianaRESUMO
Rhodopseudomonas palustris CGA009 is a Gram-negative, purple non-sulfur, metabolically diverse bacterium with wide-ranging habitats. The extraordinary ability of R. palustris to decompose a variety of raw materials and convert them into high-value products makes it an attractive host for biotechnology and industrial applications. However, being a freshwater bacterium R. palustris has limited application in highly-saline environments. Therefore, it is of great significance to obtain the salt-tolerant strain of R. palustris and understand its tolerance mechanism. In this study, R. palustris CGA009 was successfully evolved into eight salt-tolerant strains using an adaptive laboratory evolution technique. RPAS-11 (R. palustris anti-salt strain 11) was selected as the best salt-tolerant strain and was used in further studies to explore the salt-tolerance mechanism. The expression of most genes associated with the carotenoid synthesis in RPAS-11 increased significantly under high concentration of salt stress, suggesting that carotenoid synthesis is one of the reasons for the salt tolerance of RPAS-11. Gene overexpression and knockout experiments were performed to get clear about the role of carotenoids in salt stress tolerance. RPAS-11-IDI, the mutant with overexpression of IDI (Isopentenyl diphosphate isomerase) exhibited enhanced salt tolerance, whereas the knockout mutant CGA009-∆crtI showed a decline in salt tolerance. In addition, the results indicated that rhodopin, a carotenoid compound, was the key pigment responsible for the salt tolerance in R. palustris. Furthermore, the production of lycopene, a widely-used carotenoid, was also increased. Taken together, our research helps to deepen the understanding of the salt tolerance mechanism of R. palustris and also widens the application of R. palustris in highly-saline environments.
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BACKGROUND: Sesquiterpenes are designated as a large class of plant-derived natural active compounds, which have wide applications in industries of energy, food, cosmetics, medicine and agriculture. Neither plant extraction nor chemical synthesis can meet the massive market demands and sustainable development goals. Biosynthesis in microbial cell factories represents an eco-friendly and high-efficient way. Among several microorganisms, Saccharomyces cerevisiae exhibited the potential as a chassis for bioproduction of various sesquiterpenes due to its native mevalonate pathway. However, its inefficient nature limits biosynthesis of diverse sesquiterpenes at industrial grade. RESULTS: Herein, we exploited an artificial synthetic malonic acid-acetoacetyl-CoA (MAAC) metabolic pathway to switch central carbon metabolic flux for stable and efficient biosynthesis of sesquiterpene-based high-density biofuel precursor in S. cerevisiae. Through investigations at transcription and metabolism levels, we revealed that strains with rewired central metabolism can devote more sugars to ß-caryophyllene production. By optimizing the MVA pathway, the yield of ß-caryophyllene from YQ-4 was 25.8 mg/L, which was 3 times higher than that of the initial strain YQ-1. Strain YQ-7 was obtained by introducing malonic acid metabolic pathway. Combing the optimized flask fermentation process, the target production boosted by about 13-fold, to 328 mg/L compared to that in the strain YQ-4 without malonic acid metabolic pathway. CONCLUSION: This designed MAAC pathway for sesquiterpene-based high-density biofuel precursor synthesis can provide an impressive cornerstone for achieving a sustainable production of renewable fuels.
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Klebsiella pneumoniae is an opportunistic pathogen belonging to the Enterobacteriaceae family, which is the leading cause of nosocomial infections. The emergence of hypervirulent and multi-drug resistant K. pneumoniae is a serious health threat. In the process of infection, K. pneumoniae needs to adapt to different environmental conditions, and the two-component regulatory system (TCS) composed of a sensor histidine kinase and response regulator is an important bacterial regulatory system in response to external stimuli. Understanding how K. pneumoniae perceives and responds to complex environmental stimuli provides insights into TCS regulation mechanisms and new targets for drug design. In this review, we analyzed the TCS composition and summarized the regulation mechanisms of TCSs, focusing on the regulation of genes involved in virulence, antibiotic resistance, and stress response. Collectively, these studies demonstrated that several TCSs play important roles in the regulation of virulence, antibiotic resistance and stress responses of K. pneumoniae. A single two-component regulatory system can participate in the regulation of several stress responses, and one stress response process may include several TCSs, forming a complex regulatory network. However, the function and regulation mechanism of some TCSs require further study. Hence, future research endeavors are required to enhance the understanding of TCS regulatory mechanisms and networks in K. pneumoniae, which is essential for the design of novel drugs targeting TCSs.
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Infecção Hospitalar , Klebsiella pneumoniae , Humanos , Virulência/genética , Klebsiella pneumoniae/genética , Resistência Microbiana a Medicamentos , Fatores de Virulência/genética , Infecção Hospitalar/microbiologia , Antibacterianos/farmacologia , Proteínas de Bactérias/genéticaRESUMO
During agricultural production, plowing affects the existing traits of the planted soil, including environmental factors (physicochemical properties and soil enzymatic activity) and microbial community, but whether deep tillage and conventional tillage cause differences in soil microecology are unknown. In this study, the 16S rRNA high-throughput sequencing technology was combined with soil environmental factor detection to analyze the differences in microbial diversity of smokey soils at different depths. As a result, the composition and structure of microbial community varied in different soil depth after plowing. Two dominant phyla, Actinobacteria and Acidobacteria, have varied a lot between the deep-plowing treatment HS3 (the sample in 10-20 cm depth after deep-plowing treatment) sample and the conventional tillage HC3 (treatment the sample in 10-20 cm depth after conventional tillage) sample. The abundance of Actinobacteria has increased significantly, while the abundance of Acidobacteria has decreased significantly. Moreover, deep tillage increased the activity of sucrase (S-SC) and nitrate reductase (NR) in samples with soil depth below 20 cm. In summary, deep tillage disturbed spatial microbial diversity and environmental factors significantly. This would provide new guidance for improving farmland management strategies, optimizing the activation methods of soil layers, further improving crop planting soil, and increasing crop yield.
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Infections of Ralstonia solanacearum result in huge agricultural and economic losses. As known, the proposal of effective biological measures for the control of soil disease depends on the complex interactions between pathogens, soil microbiota and soil properties, which remains to be studied. Previous studies have shown that the phosphorus availability increased pathobiome abundance and infection of rhizosphere microbial networks by Ralstonia. Similarly, as a nutrient necessary for plant growth, nitrogen has also been suggested to be strongly associated with Ralstonia infection. To further reveal the relationship between soil nitrogen content, soil nitrogen metabolism and Ralstonia pathogens, we investigated the effects of R. solanacearum infection on the whole tobacco niche and its soil nitrogen metabolism. The results demonstrated that Ralstonia infection resulted in a reduction of the ammonium nitrogen in soil and the total nitrogen in plant. The microbes in rhizosphere and the plant's endophytes were also significantly disturbed by the infection. Rhodanobacter which is involved in nitrogen metabolism significantly decreased. Moreover, the load of microbial nitrogen metabolism genes in the rhizosphere soil significantly varied after the infection, resulting in a stronger denitrification process in the diseased soil. These results suggest that the application management strategies of nitrogen fertilizing and a balanced regulation of the rhizosphere and the endophytic microbes could be promising strategies in the biological control of soil-borne secondary disasters.
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Steroid hormones play an essential role in regulating physiological and reproductive development throughout the lifetime of an individual. One of the difficulties in determining endogenous substances is the lack of a blank matrix. Especially when the level of analytes is lower than the level in the so-called blank matrix. In the present study, an optimized HPLC-MS/MS method was developed and validated to quantify androstenedione (ASD), testosterone (Ts), dehydroepiandrosterone (DHEA), 5α-dihydrotestosterone (DHT), and progesterone (P) in serum samples from healthy people using PBS (pH = 7.4) as the blank surrogate matrix. Simultaneously, the method investigated the characteristics of NaCl, bull serum albumin, pure water as surrogate matrices for the analysis of steroid hormones. The data showed that the matrix effects of ASD, Ts, DHEA, DHT, and P in the same groups were not significantly different between PBS and twice charcoal-stripped serum (CS2S) as a blank surrogate matrix. Furthermore, the LLOQ using PBS as the blank matrix was up to 0.005 ng/mL for ASD, Ts, and P and 0.05 ng/mL for DHEA and DHT. The reference ranges of concentration (CPBS) of 5 steroid hormones were provided. Compared to the concentration with CS2S (CCSS) as the blank surrogate matrix, the relative biases (RBs) of Ts, DHT, P, and DHEA were finally stabilized at approximately -0.7%, -15%, -1.2%, and 9.2%, respectively. The results suggest that, in the cases of special required, the developed HPLC-MS/MS method can be used to determine the absolute concentration of 5 hormones in biological samples with PBS as the blank surrogate matrix.
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Androstenodiona/sangue , Cromatografia Líquida de Alta Pressão/métodos , Di-Hidrotestosterona/sangue , Progesterona/sangue , Espectrometria de Massas em Tandem/métodos , Testosterona/sangue , Desidroepiandrosterona , HumanosRESUMO
Farnesene, as an important sesquiterpene isoprenoid polymer of acetyl-CoA, is a renewable feedstock for diesel fuel, polymers, and cosmetics. It has been widely applied in agriculture, medicine, energy, and other fields. In recent years, farnesene biosynthesis is considered a green and economical approach because of its mild reaction conditions, low environmental pollution, and sustainability. Metabolic engineering has been widely applied to construct cell factories for farnesene biosynthesis. In this paper, the research progress, common problems, and strategies of farnesene biosynthesis are reviewed. They are mainly described from the perspectives of the current status of farnesene biosynthesis in different host cells, optimization of the metabolic pathway for farnesene biosynthesis, and key enzymes for farnesene biosynthesis. Furthermore, the challenges and prospects for future farnesene biosynthesis are discussed.
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Engenharia Metabólica , Sesquiterpenos , Acetilcoenzima A/metabolismo , Redes e Vias Metabólicas , TerpenosRESUMO
Plant biomass is a highly abundant renewable resource that can be converted into several types of high-value-added products, including chemicals, biofuels and advanced materials. In the last few decades, an increasing number of biomass species and processing techniques have been developed to enhance the application of plant biomass followed by the industrial application of some of the products, during which varied technologies have been successfully developed. In this review, we summarize the different sources of plant biomass, the evolving technologies for treating it, and the various products derived from plant biomass. Moreover, the challenges inherent in the valorization of plant biomass used in high-value-added products are also discussed. Overall, with the increased use of plant biomass, the development of treatment technologies, and the solution of the challenges raised during plant biomass valorization, the value-added products derived from plant biomass will become greater in number and more valuable.
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The overuse of chemical fertilizers has resulted in the degradation of the physicochemical properties and negative changes in the microbial profiles of agricultural soil. These changes have disequilibrated the balance in agricultural ecology, which has resulted in overloaded land with low fertility and planting obstacles. To protect the agricultural soil from the effects of unsustainable fertilization strategies, experiments of the reduction of nitrogen fertilization at 10, 20, and 30% were implemented. In this study, the bacterial responses to the reduction of nitrogen fertilizer were investigated. The bacterial communities of the fertilizer-reducing treatments (D10F, D20F, and D30F) were different from those of the control group (CK). The alpha diversity was significantly increased in D20F compared to that of the CK. The analysis of beta diversity revealed variation of the bacterial communities between fertilizer-reducing treatments and CK, when the clusters of D10F, D20F, and D30F were separated. Chemical fertilizers played dominant roles in changing the bacterial community of D20F. Meanwhile, pH, soil organic matter, and six enzymes (soil sucrase, catalase, polyphenol oxidase, urease, acid phosphatase, and nitrite reductase) were responsible for the variation of the bacterial communities in fertilizer-reducing treatments. Moreover, four of the top 20 genera (unidentified JG30-KF-AS9, JG30-KF-CM45, Streptomyces, and Elsterales) were considered as key bacteria, which contributed to the variation of bacterial communities between fertilizer-reducing treatments and CK. These findings provide a theoretical basis for a fertilizer-reducing strategy in sustainable agriculture, and potentially contribute to the utilization of agricultural resources through screening plant beneficial bacteria from native low-fertility soil.