Treatment of Arabidopsis (Arabidopsis thaliana) with a necrosis- and ethylene-inducing peptide (Nep1) from Fusarium oxysporum inhibited both root and cotyledon growth and triggered cell death, thereby generating necrotic spots. Nep1-like proteins are produced by divergent microbes, many of which are plant pathogens. Nep1 in the plant was localized to the cell wall and cytosol based on immunolocalization results. The ratio of chlorophyll a fluorescence (F685 nm/F730 nm) significantly decreased after 75-min treatment with Nep1 in comparison to the control. This suggested that a short-term compensation of photosynthesis occurred in response to localized damage to cells. The concentrations of most water-soluble metabolites analyzed were reduced in Arabidopsis seedlings after 6 h of Nep1 treatment, indicating that the integrity of cellular membranes had failed. Microarray results showed that short-term treatment with Nep1 altered expression of numerous genes encoding proteins putatively localized to organelles, especially the chloroplast and mitochondria. Short-term treatment with Nep1 induced multiple classes of genes involved in reactive oxygen species production, signal transduction, ethylene biosynthesis, membrane modification, apoptosis, and stress. Quantitative PCR was used to confirm the induction of genes localized in the chloroplast, mitochondria, and plasma membrane, and genes responsive to calcium/calmodulin complexes, ethylene, jasmonate, ethylene biosynthesis, WRKY, and cell death. The majority of Nep1-induced genes has been associated with general stress responses but has not been critically linked to resistance to plant disease. These results are consistent with Nep1 facilitating cell death as a component of diseases caused by necrotrophic plant pathogens.
This study aimed to enhance the production of D-mannose and bioethanol from spent coffee grounds (SCGs) through pretreatment, enzymatic hydrolysis, and selective fermentation. Combined pretreatment with alkali, bleaching, and NaOH−hydrogen peroxide (NH) significantly increased glucose and mannose yield 5.44 and 3.49 times, respectively. After enzymatic hydrolysis using cellulase and mannanase, the pretreated SCGs produced high glucose and mannose yields of 15.3 and 10.6 mg/mL, respectively. Additionally, the mutant Pichia stipitis MH05 strain selectively consumed glucose during fermentation, resulting in a significant amount of mannose (79.9%) remaining after 48 h. In conclusion, SCGs demonstrate potential usefulness in D-mannose and bioethanol production, and combining enzymatic hydrolysis with selective fermentation offers an effective approach for achieving environmental sustainability and economic benefits.
Corynebacterium glutamicum is a useful microbe to produce succinic acid, a bio-based platform chemical, under anaerobic condition. The knock-out mutant of lactate dehydrogenase 1 gene (ΔldhA-6) and co-expression of succinic acid transporter (Psod:sucE- ΔldhA) were generated by using CRISPR-Cpf1 genome editing system. HAPC (hydrogen peroxide and acetic acid) pretreatment is a highly efficient method for enzymatic hydrolysis of softwood and the hydrolysate was used for production of succinic acid. In the 15% hydrolysate (Pinus densiflora), the best condition for ΔldhA mutant to produce succinic acid from the hydrolysate was confirmed to ferment 4% hydrolysate, resulted in 14.82 g L-1 succinic acid production for 6 h, which reached to 2.47 g L-1 h-1 productivity. No production of acetic acid and lactic acid was detected during the fermentation. The co-expression transformant, [Psod:sucE- ΔldhA], produced 17.70 g L-1 succinic acid in 6 h, presenting a productivity of 2.95 g L-1 h-1 on the 4% hydrolysate. In the fed-batch system, 39.67 g L-1 succinic acid was produced for 48 h. The yield of succinic acid from reducing sugars in the hydrolysate is approximately 56.71%, while the yield of succinic acid from glucose alone as the main substrate is approximately 84.4%. These results indicated that the production of succinic acid from softwood has potential applications in alternative biochemical processes, and minimizing the loss of sugars during enzymatic hydrolysis and fermentation can lead to more economic benefits in succinic acid production from lignocellulosic biomass.
Corynebacterium glutamicum is a useful microbe to produce succinic acid, a bio-based platform chemical, under anaerobic condition. The knock-out mutant of lactate dehydrogenase 1 gene, Δldh1-6, was generated by using CRISPR-Cpf1 genome editing system. HAPC (hydrogen peroxide and acetic acid) pretreatment is a softwood-favorable. In the 1-5% hydrolysate, the best condition to produce succinic acid from the hydrolysate was confirmed to ferment 4% hydrolysate, resulted in 14.82 g L-1 succinic acid production for 6 h, which reached to 2.47 g L-1 h-1 productivity. No production of acetic acid and lactic acid was detected during the fermentation. However, 2.0 g L-1 lactic acid and 0.41 g L-1 acetic acid were formed in the fermentation of 5% hydrolysate while 9.64 g L-1 succinic acid was produced. These results show that the single gene knock-out, Δldh1-6 mutant, is sufficiently available for succinic acid production from hydrolysate of pine wood.
Journal Article Immunolocalization of a Recombinant Cellulase in Transgenic Tobacco Plants Get access H J Bae, H J Bae Laval University, Ste-foy, Quebec, Canada G1K 7P4 Search for other works by this author on: Oxford Academic Google Scholar H Chamberland, H Chamberland Laval University, Ste-foy, Quebec, Canada G1K 7P4 Search for other works by this author on: Oxford Academic Google Scholar S Laberge, S Laberge Centre de Recherches et de Agriculture et Agroalimentaire Canada G1V 2J3 Search for other works by this author on: Oxford Academic Google Scholar Y S Kim Y S Kim Chonnam National University, Kwangju, Korea 500-757 Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 8, Issue S02, 1 August 2002, Pages 1084–1085, https://doi.org/10.1017/S1431927602106982 Published: 01 August 2002
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