scholarly journals Overexpression of D-Xylose Reductase (xyl1) Gene and Antisense Inhibition of D-Xylulokinase (xyiH) Gene Increase Xylitol Production inTrichoderma reesei

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yuanyuan Hong ◽  
Mehdi Dashtban ◽  
Greg Kepka ◽  
Sanfeng Chen ◽  
Wensheng Qin
Keyword(s):  
Genetic Engineering ◽  
Copy Number ◽  
Xylose Reductase ◽  
Mrna Level ◽  
Antisense Inhibition ◽  
Xylitol Production ◽  
High Homology ◽  
Wild Type ◽  
Reductase Gene ◽  
Antisense Construct

T. reeseiis an efficient cellulase producer and biomass degrader. To improve xylitol production inTrichoderma reeseistrains by genetic engineering, two approaches were used in this study. First, the presumptive D-xylulokinase gene inT. reesei(xyiH), which has high homology to known fungi D-xylulokinase genes, was silenced by transformation ofT. reeseiQM9414 strain with an antisense construct to create strain S6-2-2. The expression of thexyiHgene in the transformed strain S6-2-2 decreased at the mRNA level, and D-xylulokinase activity decreased after 48 h of incubation. This led to an increase in xylitol production from undetectable levels in wild-typeT. reeseiQM9414 to 8.6 mM in S6-2-2. TheT. reeseiΔxdh is a xylose dehydrogenase knockout strain with increased xylitol production compared to the wild-typeT. reeseiQM9414 (22.8 mM versus undetectable). The copy number of the xylose reductase gene (xyl1) inT. reeseiΔxdh strain was increased by genetic engineering to create a new strain Δ9-5-1. The Δ9-5-1 strain showed a higherxyl1 expression and a higher yield of xylose reductase, and xylitol production was increased from 22.8 mM to 24.8 mM. Two novel strains S6-2-2 and Δ9-5-1 are capable of producing higher yields of xylitol.T. reeseihas great potential in the industrial production of xylitol.

scholarly journals Assessing the Potential of Newly Isolated Pichia Fermentans for Xylitol Production Using Non-Detoxified Xylose Rich Pre-Hydrolysate Derived from Sugarcane Bagasse

2020 ◽  
Author(s):  
Ashish A Prabhu ◽  
Ekkarin Bosakornranut ◽  
Yassin Amraoui ◽  
Deepti Agarwal ◽  
Frederic Coulon ◽  
...  
Keyword(s):  
Sugarcane Bagasse ◽  
Type Strain ◽  
Shake Flask ◽  
Wild Type Strain ◽  
Xylose Reductase ◽  
Value Added ◽  
Xylitol Production ◽  
Wild Type ◽  
Conversion Yield ◽  
Cell Factories

Abstract Background: Integrated management of hemicellulosic fraction and its economical transformation to value-added products is the key driver towards sustainable second-generation biorefineries. In this aspect microbial cell factories are harnessed for sustainable production of biochemicals by valorising C5 and C6 sugars generated from agro-industrial waste. However, most of the strains can effectively consume C6 sugars but lacks pentose metabolism pathway. The effective utilization of both pentose and hexose sugars is key for economical biorefinery. Results: In the current study, the ability of a newly isolated xylose assimilating Pichia fermentans was explored for xylitol production. The wild type strain robustly grew on xylose and produced xylitol with >40% conversion yield. Mutagenesis with ethyl methanesulphonate (EMS) yielded seven mutants. The mutant obtained after 15 min exposure, exhibited best xylose bioconversion efficiency. This mutant under shake flask conditions produced maximum xylitol titre and yield of 34.0 g/L and 0.68 g/g, respectively. oweverHoHHHoHowever, under same conditions, the control wild type strain accumulated 27.0 g/L xylitol with a conversion yield of 0.45 g/g. Improved performance of the mutant was attributed to 34.6% activity enhancement in xylose reductase with simultaneous reduction of xylitol dehydrogenase activity by 22.9%. Later, the culture medium was optimized using statistical design and validated at shake flask and bioreactor level. Bioreactor studies affirmed the competence of mutant in xylitol accumulation. The xylitol titre and yield obtained with pure xylose were 98.9 g/L and 0.67 g/g, respectively while xylitol produced using non-detoxified xylose rich pre-hydrolysate from sugarcane bagasse was 79.0 g/L with an overall yield of 0.54 g/g. Conclusion: This study established the potential of P. fermentans in successfully valorising the hemicellulosic fraction for sustainable xylitol production.

scholarly journals Xylitol production is increased by expression of codon-optimized Neurospora crassa xylose reductase gene in Candida tropicalis

2011 ◽  
Vol 35 (1-2) ◽  
pp. 191-198 ◽  
Author(s):  
Woo Young Jeon ◽  
Byoung Hoon Yoon ◽  
Byoung Sam Ko ◽  
Woo Yong Shim ◽  
Jung Hoe Kim
Keyword(s):  
Neurospora Crassa ◽  
Candida Tropicalis ◽  
Xylose Reductase ◽  
Xylitol Production ◽  
Reductase Gene

Stable expression of xylose reductase gene enhances xylitol production in recombinant Saccharomyces cerevisiae

2002 ◽  
Vol 30 (6) ◽  
pp. 809-816 ◽  
Author(s):  
Yun-Seung Chung ◽  
Myoung-Dong Kim ◽  
Woo-Jong Lee ◽  
Yeon-Woo Ryu ◽  
Ji-Hyeon Kim ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Xylose Reductase ◽  
Stable Expression ◽  
Xylitol Production ◽  
Recombinant Saccharomyces Cerevisiae ◽  
Reductase Gene

scholarly journals A 44-kb deleted-type copy number variation is associated with decreasing complement component activity and calf mortality in Japanese Black cattle

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Shinji Sasaki ◽  
Youko Miki ◽  
Takayuki Ibi ◽  
Hiroyuki Wakaguri ◽  
Yuichi Yoshida ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Copy Number Variation ◽  
Copy Number ◽  
Risk Allele ◽  
Wild Type ◽  
Japanese Black Cattle ◽  
Complement Activity ◽  
Categorical Trait ◽  
Number Variation ◽  
Calf Mortality

Abstract Background Calf mortality generally occurs in calves prior to weaning, which is a serious problem in cattle breeding. Several causative variants of monogenic Mendelian disorders in calf mortality have been identified, whereas genetic factors affecting the susceptibility of calves to death are not well known. To identify variants associated with calf mortality in Japanese Black cattle, we evaluated calf mortality as a categorical trait with a threshold model and performed a genome-wide copy number variation (CNV) association study on calf mortality. Results We identified a 44-kb deleted-type CNV ranging from 103,317,687 to 103,361,802 bp on chromosome 5, which was associated with the mortality of 1–180-day-old calves. The CNV harbored C1RL, a pseudogene, and an IncRNA localized in the C1R and C1S gene cluster, which is a component of the classical complement activation pathway for immune complexes for infectious pathogens. The average complement activity in CNVR_221 homozygotes at postnatal day 7 was significantly lower than that of wild-type animals and heterozygotes. The frequency of the risk allele in dead calves suffering from diarrhea and pneumonia and in healthy cows was 0.35 and 0.28, respectively (odds ratio = 2.2, P = 0.016), suggesting that CNVR_221 was associated with the mortality of Japanese Black calves suffering from an infectious disease. Conclusions This study identified a deleted-type CNV associated with the mortality of 1–180-day-old calves. The complement activity in CNVR_221 homozygotes was significantly lower than that in heterozygotes and wild type animals. The frequency of the risk allele was higher in dead calves suffering from an infectious disease than in healthy cows. These results suggest that the existence of CNVR_221 in calves could be attributed to a reduction in complement activity, which in turn leads to susceptibility to infections. Thus, the risk allele could serve as a useful marker to reduce the mortality of infected Japanese Black calves.

scholarly journals Production of bio-xylitol from d-xylose by an engineered Pichia pastoris expressing a recombinant xylose reductase did not require any auxiliary substrate as electron donor

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Tai Man Louie ◽  
Kailin Louie ◽  
Samuel DenHartog ◽  
Sridhar Gopishetty ◽  
Mani Subramanian ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Electron Donor ◽  
Low Cost ◽  
Standard Procedure ◽  
Xylose Reductase ◽  
Animal Nutrition ◽  
Whole Cells ◽  
Reductase Gene ◽  
Biocatalytic Reaction ◽  
Ketone Reductases

Abstract Background Xylitol is a five-carbon sugar alcohol that has numerous beneficial health properties. It has almost the same sweetness as sucrose but has lower energy value compared to the sucrose. Metabolism of xylitol is insulin independent and thus it is an ideal sweetener for diabetics. It is widely used in food products, oral and personal care, and animal nutrition as well. Here we present a two-stage strategy to produce bio-xylitol from d-xylose using a recombinant Pichia pastoris expressing a heterologous xylose reductase gene. The recombinant P. pastoris cells were first generated by a low-cost, standard procedure. The cells were then used as a catalyst to make the bio-xylitol from d-xylose. Results Pichia pastoris expressing XYL1 from P. stipitis and gdh from B. subtilis demonstrated that the biotransformation was very efficient with as high as 80% (w/w) conversion within two hours. The whole cells could be re-used for multiple rounds of catalysis without loss of activity. Also, the cells could directly transform d-xylose in a non-detoxified hemicelluloses hydrolysate to xylitol at 70% (w/w) yield. Conclusions We demonstrated here that the recombinant P. pastoris expressing xylose reductase could transform d-xylose, either in pure form or in crude hemicelluloses hydrolysate, to bio-xylitol very efficiently. This biocatalytic reaction happened without the external addition of any NAD(P)H, NAD(P)+, and auxiliary substrate as an electron donor. Our experimental design & findings reported here are not limited to the conversion of d-xylose to xylitol only but can be used with other many oxidoreductase reactions also, such as ketone reductases/alcohol dehydrogenases and amino acid dehydrogenases, which are widely used for the synthesis of high-value chemicals and pharmaceutical intermediates.

scholarly journals Molecular Basis of In Vivo Resistance to Sulfadoxine-Pyrimethamine in African Adult Patients Infected withPlasmodium falciparum Malaria Parasites

1998 ◽  
Vol 42 (7) ◽  
pp. 1811-1814 ◽  
Author(s):  
Leonardo K. Basco ◽  
Rachida Tahar ◽  
Pascal Ringwald
Keyword(s):  
Dihydrofolate Reductase ◽  
Point Mutations ◽  
Gene Mutations ◽  
Adult Patients ◽  
Wild Type ◽  
Dihydropteroate Synthase ◽  
Reductase Gene ◽  
Parasite Populations

ABSTRACT In vitro sulfadoxine and pyrimethamine resistance has been associated with point mutations in the dihydropteroate synthase and dihydrofolate reductase domains, respectively, but the in vivo relevance of these point mutations has not been well established. To analyze the correlation between genotype and phenotype, 10 Cameroonian adult patients were treated with sulfadoxine-pyrimethamine and followed up for 28 days. After losses to follow-up (n = 1) or elimination of DNA samples due to mixed parasite populations with pyrimethamine-sensitive and pyrimethamine-resistant profiles (n = 3), parasite genomic DNA from day 0 blood samples of six patients were analyzed by DNA sequencing. Three patients who were cured had isolates characterized by a wild-type or mutant dihydrofolate reductase gene (with one or two mutations) and a wild-type dihydropteroate synthase gene. Three other patients who failed to respond to sulfadoxine-pyrimethamine treatment carried isolates with triple dihydrofolate reductase gene mutations and either a wild-type or a mutant dihydropteroate synthase gene. Three dihydrofolate reductase gene codons (51, 59, and 108) may be reliable genetic markers that can accurately predict the clinical outcome of sulfadoxine-pyrimethamine treatment in Africa.

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