scholarly journals Biosynthesis and metabolic engineering of 1-hydroxyphenazine in Pseudomonas chlororaphis H18

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Yupeng Wan ◽  
Hongchen Liu ◽  
Mo Xian ◽  
Wei Huang
Keyword(s):  
Growth Rate ◽  
Metabolic Engineering ◽  
Rational Design ◽  
Plant Pathogens ◽  
Antibacterial Activities ◽  
Pseudomonas Chlororaphis ◽  
Powerful Method ◽  
Microbial Metabolite ◽  
Precursor Pool ◽  
Growth Promoting

Abstract Background 1-Hydroxyphenazine (1-OH-PHZ) is a phenazine microbial metabolite with broad-spectrum antibacterial activities against a lot of plant pathogens. However, its use is hampered by the low yield all along. Metabolic engineering of microorganisms is an increasingly powerful method for the production of valuable organisms at high levels. Pseudomonas chlororaphis is recognized as a safe and effective plant rhizosphere growth-promoting bacterium, and faster growth rate using glycerol or glucose as a renewable carbon source. Therefore, Pseudomonas chlororaphis is particularly suitable as the chassis cell for the modification and engineering of phenazines. Results In this study, enzyme PhzS (monooxygenase) was heterologously expressed in a phenazine-1-carboxylic acid (PCA) generating strain Pseudomonas chlororaphis H18, and 1-hydroxyphenazine was isolated, characterized in the genetically modified strain. Next, the yield of 1-hydroxyphenazine was systematically engineered by the strategies including (1) semi-rational design remodeling of crucial protein PhzS, (2) blocking intermediate PCA consumption branch pathway, (3) enhancing the precursor pool, (4) engineering regulatory genes, etc. Finally, the titer of 1-hydroxyphenazine reached 3.6 g/L in 5 L fermenter in 54 h. Conclusions The 1-OH-PHZ production of Pseudomonas chlororaphis H18 was greatly improved through systematically engineering strategies, which is the highest, reported to date. This work provides a promising platform for 1-hydroxyphenazine engineering and production. Graphical Abstract

Isolation, identification and in silico study of native cellulase producing bacteria

2019 ◽  
Vol 17 ◽  
Author(s):  
Farzane Kargar ◽  
Mojtaba Mortazavi ◽  
Mahmood Maleki ◽  
Masoud Torkzadeh Mahani ◽  
Younes Ghasemi ◽  
...  
Keyword(s):  
Growth Rate ◽  
Bacillus Cereus ◽  
16S Rdna ◽  
Enzyme Production ◽  
Rational Design ◽  
Cellulase Production ◽  
Bacillus Species ◽  
Bacillus Sp ◽  
Chain Polymer ◽  
Bacillus Toyonensis

Aims: The purpose of this study was to screen the bacteria producing cellulase enzymes and their bioinformatics studies. Background: Cellulose is a long-chain polymer of glucose that hydrolyzes by cellulases to glucose molecules. In order to design the new biotechnological applications, some strategies have been used as increasing the efficiency of enzyme production, generating cost-effective enzymes, producing stable enzymes and identification of new strains. Objective: On the other hand, some bacteria special features have made them suitable candidates for the identification of the new source of enzymes. In this regard, some native strains of bacteria were screened. Method: These bacteria were grown on a culture containing the liquid M9 media containing CMC to ensure the synthesis of cellulase. The formation of a clear area in the culture medium indicated decomposition of cellulose. In the following, the DNA of these bacteria were extracted and their 16S rDNA genes were amplified. Result: The results show that nine samples were able to synthesize cellulase. In following, these strains were identified using 16S rDNA. The results show that these screened bacteria belonged to the Bacillus sp., Alcaligenes sp., Alcaligenes sp., and Enterobacter sp.conclusionThe enzyme activity analysis shows that the Bacillus toyonensis, Bacillus sp. strain XA15-411 Bacillus cereus have produced the maximum yield of cellulases. However, these amounts of enzyme production in these samples are not proportional to their growth rate. As the bacterial growth chart within 4 consecutive days shows that the Alcaligenes sp. Bacillus cereus, Bacillus toyonensis, Bacillus sp. strain XA15-411 have a maximum growth rate. The study of the phylogenetic tree also shows that Bacillus species are more abundant in the production of cellulase enzyme. These bioinformatics analyses show that the Bacillus species have different evolutionary relationships and evolved in different evolutionary time. Other: However, for maximum cellulase production by this bacteria, some information as optimum temperature, optimum pH, carbon and nitrogen sources are needed for the ideal formulation of media composition. The cellulase production is closely controlled in microorganisms and the cellulase yields appear to depend on a variety of factors. However, the further studies are needed for cloning, purification and application of these new microbial cellulases in the different commercial fields as in food, detergent, and pharmaceutical, paper, textile industries and also various chemical industries. However, these novel enzymes can be further engineered through rational design or using random mutagenesis techniques.

scholarly journals Diversity, biocontrol, and growth promotion potential of culturable endophytic fungi isolated from root, shoot, and leaf of wild Phoebe bournei (Hemsl.) Yang across the seasons

2021 ◽  
Author(s):  
Cun Yu ◽  
Ying Yao
Keyword(s):  
Plant Growth ◽  
Endophytic Fungi ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Leaf Spot Disease ◽  
Plant Growth Promoting Activities ◽  
Potential Applicability ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Phoebe Bournei

Endophytic fungi were isolated from Phoebe bournei and their diversity and antimicrobial and plant growth-promoting activities were investigated. Of the 389 isolated endophytic fungi, 88.90% belonged to phylum Ascomycota and 11.10% to phylum Basidiomycota. The isolates were grouped into four taxonomic classes, 11 orders, 30 genera, and 45 species based on internal transcribed spacer sequencing and morphologic analysis. The host showed a strong affinity for the genera Diaporthe and Phyllosticta. The diversity of the fungi was highest in autumn, followed by spring and summer, and was lowest in winter. The fungi exhibited notable tissue specificity in P. bournei, and the species richness and diversity were highest in the root across all seasons. Five isolates showed antimicrobial activity against eight plant pathogens, and reduced the incidence of leaf spot disease in P. bournei. Additionally, 9 biocontrol isolates showed plant growth-promoting activity, with five significantly promoting P. bournei seedling growth. This is the first report on the endophytic fungi of P. bournei and their potential applicability to plant disease control and growth promotion.

scholarly journals Inulin results in increased levels of β-catenin and cyclin D1 as the adenomas increase in size from small to large in the Min/+ mouse

2008 ◽  
Vol 99 (5) ◽  
pp. 963-970 ◽  
Author(s):  
Marjo Misikangas ◽  
Heidi Tanayama ◽  
Johanna Rajakangas ◽  
Jere Lindén ◽  
Anne-Maria Pajari ◽  
...  
Keyword(s):  
Growth Rate ◽  
Cyclin D1 ◽  
Control Diet ◽  
Cell Signalling ◽  
Control Group ◽  
High Fat ◽  
Colon Tumorigenesis ◽  
Growth Promoting ◽  
Dietary Strategies ◽  
Metalloproteinase 9

The mechanism that drives the growth of some colonic adenomas towards malignancy, while permitting others to remain for decades in quiescence, remains unknown. Diets can alter the growth rate of intestinal tumours but it is still unknown whether diets are able to alter the molecular biology of these adenomas in a way that predicts further outcome. To address this issue we fed Min/+ mice with two diets known to lead to different adenoma outcomes: a high-fat control diet (n 15) or a high-fat inulin-enriched (10 % w/w) diet (n 13). To study the effect of diet on cell signalling during adenoma growth, the adenomas of each Min/+ mouse were divided into three size-categories, and the levels of β-catenin, E-cadherin, cyclin D1 and matrix metalloproteinase-9, which are known to be involved in colon tumorigenesis, were determined. The growth-promoting inulin diet resulted in more large adenomas than the control feeding (P = 0·003) and doubled the total area of the adenomas (P = 0·008). The inulin diet increased the expression of nuclear β-catenin (P = 0·004) and its target cyclin D1 (P = 0·017) as the adenomas increased in size from small to large, indicating the presence of an accelerated cancerous process. Neither phenomenon was seen in the control group during adenoma growth. Our results suggest that in addition to the number, size, and growth rate of adenomatous polyps, the signalling pattern of the adenomas should also be considered when evaluating preventive dietary strategies.

scholarly journals Rational design of minimal synthetic promoters for plants

2020 ◽  
Vol 48 (21) ◽  
pp. 11845-11856 ◽  
Author(s):  
Yao-Min Cai ◽  
Kalyani Kallam ◽  
Henry Tidd ◽  
Giovanni Gendarini ◽  
Amanda Salzman ◽  
...  
Keyword(s):  
Rational Design ◽  
Plant Pathogens ◽  
Critical Role ◽  
Experimental System ◽  
Computational Design ◽  
Regulatory Elements ◽  
Regulatory Function ◽  
Synthetic Promoters ◽  
Sequence Elements ◽  
Plant Promoters

Abstract Promoters serve a critical role in establishing baseline transcriptional capacity through the recruitment of proteins, including transcription factors. Previously, a paucity of data for cis-regulatory elements in plants meant that it was challenging to determine which sequence elements in plant promoter sequences contributed to transcriptional function. In this study, we have identified functional elements in the promoters of plant genes and plant pathogens that utilize plant transcriptional machinery for gene expression. We have established a quantitative experimental system to investigate transcriptional function, investigating how identity, density and position contribute to regulatory function. We then identified permissive architectures for minimal synthetic plant promoters enabling the computational design of a suite of synthetic promoters of different strengths. These have been used to regulate the relative expression of output genes in simple genetic devices.

scholarly journals Actinomycetes, promising tools to control plant diseases and to promote plant growth

2005 ◽  
Vol 82 (3) ◽  
pp. 85-102 ◽  
Author(s):  
C.L. Doumbou ◽  
M.K. Hamby Salove ◽  
D.L. Crawford ◽  
C. Beaulieu
Keyword(s):  
Plant Growth ◽  
Plant Pathogens ◽  
Soil Microbial Biomass ◽  
Extracellular Enzymes ◽  
Control Plant ◽  
Plant Diseases ◽  
Soil Microbial ◽  
Plant Growth Promoting ◽  
Promote Plant Growth ◽  
Growth Promoting

Actinomycetes represent a high proportion of the soil microbial biomass and have the capacity to produce a wide variety of antibiotics and of extracellular enzymes. Several strains of actinomycetes have been found to protect plants against plant diseases. This review focuses on the potential of actinomycetes as (a) source of agroactive compounds, (b) plant growth promoting organisms, and (c) biocontrol tools of plant diseases. This review also addresses examples of biological control of fungal and bacterial plant pathogens by actinomycetes species which have already reached the market or are likely to be exploited commercially within the next few years.

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