scholarly journals Engineering a feedback inhibition-insensitive plant dihydrodipicolinate synthase to increase lysine content in Camelina sativa seeds

2021 ◽  
Author(s):  
Alex Huang ◽  
Cathy Coutu ◽  
Myrtle Harrington ◽  
Kevin Rozwadowski ◽  
Dwayne D. Hegedus
Keyword(s):  
Animal Feed ◽  
Specific Activity ◽  
Higher Plants ◽  
Feedback Inhibition ◽  
Camelina Sativa ◽  
Site Directed Mutagenesis ◽  
Oilseed Crop ◽  
Lysine Content ◽  
Dihydrodipicolinate Synthase ◽  
The Impact

AbstractCamelina sativa (camelina) is emerging as an alternative oilseed crop due to its short growing cycle, low input requirements, adaptability to less favorable growing environments and a seed oil profile suitable for biofuel and industrial applications. Camelina meal and oil are also registered for use in animal and fish feeds; however, like meals derived from most cereals and oilseeds, it is deficient in certain essential amino acids, such as lysine. In higher plants, the reaction catalyzed by dihydrodipicolinate synthase (DHDPS) is the first committed step in the biosynthesis of lysine and is subject to regulation by lysine through feedback inhibition. Here, we report enhancement of lysine content in C. sativa seed via expression of a feedback inhibition-insensitive form of DHDPS from Corynebacterium glutamicums (CgDHDPS). Two genes encoding C. sativa DHDPS were identified and the endogenous enzyme is partially insensitive to lysine inhibition. Site-directed mutagenesis was used to examine the impact of alterations, alone and in combination, present in lysine-desensitized DHDPS isoforms from Arabidopsis thaliana DHDPS (W53R), Nicotiana tabacum (N80I) and Zea mays (E84K) on C. sativa DHDPS lysine sensitivity. When introduced alone, each of the alterations decreased sensitivity to lysine; however, enzyme specific activity was also affected. There was evidence of molecular or structural interplay between residues within the C. sativa DHDPS allosteric site as coupling of the W53R mutation with the N80V mutation decreased lysine sensitivity of the latter, but not to the level with the W53R mutation alone. Furthermore, the activity and lysine sensitivity of the triple mutant (W53R/N80V/E84T) was similar to the W53R mutation alone or the C. glutamicum DHDPS. The most active and most lysine-insensitive C. sativa DHDPS variant (W53R) was not inhibited by free lysine up to 1 mM, comparable to the C. glutamicums enzyme. Seed lysine content increased 13.6 -22.6% in CgDHDPS transgenic lines and 7.6–13.2% in the mCsDHDPS lines. The high lysine-accumulating lines from this work may be used to produce superior quality animal feed with improved essential amino acid profile.

scholarly journals Changes in Glucosinolates, Sinapine and Flavonols during Seed Development of Camelina sativa (L.) Crantz

2018 ◽  
pp. 1-5
Author(s):  
Roberto Russo ◽  
Remo Reggiani
Keyword(s):  
Seed Development ◽  
Animal Feed ◽  
Sinapic Acid ◽  
Camelina Sativa ◽  
The Other ◽  
Seed Maturation ◽  
Oilseed Crop ◽  
Seed Composition ◽  
Other Substances ◽  
Camelina Seed

Camelina sativa (L.) Crantz is an oilseed crop whose oil is used as biofuel and the meal as animal feed. While the seed composition is widely documented, little is known about variations in the concentration of some compounds during seed development of camelina. The aim of this study was to characterize changes in the content of glucosinolates, sinapine, sinapic acid and flavonols (quercetin and koempferol) at different stages of seed maturation. Glucosinolates are accumulated in camelina seed in the first 4 weeks after pollination, while the other substances were transiently accumulated during development and may play a role in seed development.

scholarly journals Engineering of Phytase for Improved Activity at Low pH

2002 ◽  
Vol 68 (4) ◽  
pp. 1907-1913 ◽  
Author(s):  
Andrea Tomschy ◽  
Roland Brugger ◽  
Martin Lehmann ◽  
Allan Svendsen ◽  
Kurt Vogel ◽  
...  
Keyword(s):  
Animal Feed ◽  
Specific Activity ◽  
Three Dimensional ◽  
Industrial Applications ◽  
Low Ph ◽  
Site Directed Mutagenesis ◽  
Single Mutation ◽  
Sequence Alignments ◽  
Ph Optimum ◽  
Double Mutation

ABSTRACT For industrial applications in animal feed, a phytase of interest must be optimally active in the pH range prevalent in the digestive tract. Therefore, the present investigation describes approaches to rationally engineer the pH activity profiles of Aspergillus fumigatus and consensus phytases. Decreasing the negative surface charge of the A. fumigatus Q27L phytase mutant by glycinamidylation of the surface carboxy groups (of Asp and Glu residues) lowered the pH optimum by ca. 0.5 unit but also resulted in 70 to 75% inactivation of the enzyme. Alternatively, detailed inspection of amino acid sequence alignments and of experimentally determined or homology modeled three-dimensional structures led to the identification of active-site amino acids that were considered to correlate with the activity maxima at low pH of A. niger NRRL 3135 phytase, A. niger pH 2.5 acid phosphatase, and Peniophora lycii phytase. Site-directed mutagenesis confirmed that, in A. fumigatus wild-type phytase, replacement of Gly-277 and Tyr-282 with the corresponding residues of A. niger phytase (Lys and His, respectively) gives rise to a second pH optimum at 2.8 to 3.4. In addition, the K68A single mutation (in both A. fumigatus and consensus phytase backbones), as well as the S140Y D141G double mutation (in A. fumigatus phytase backbones), decreased the pH optima with phytic acid as substrate by 0.5 to 1.0 unit, with either no change or even a slight increase in maximum specific activity. These findings significantly extend our tools for rationally designing an optimal phytase for a given purpose.

Markets for Purchased Farm Inputs

2005 ◽  
pp. 60-71
Author(s):  
E. Serova ◽  
O. Shick
Keyword(s):  
Agricultural Policy ◽  
Financial Constraints ◽  
Information Sources ◽  
Animal Feed ◽  
Government Policies ◽  
Market Institutions ◽  
Policy Makers ◽  
Government Organizations ◽  
The Impact ◽  
Farm Inputs

Russian policy makers argue that agriculture suffers from decapitalization due to financial constraints faced by producers. This view is the basis for the national agricultural policy, which emphasizes reimbursement of input costs and substitutes government and quasi-government organizations for missing market institutions. The article evaluates the availability of purchased farm inputs, the efficiency of their use, the main problems in the emergence of market institutions, and the impact of government policies. The analysis focuses on five groups of purchased inputs: farm machinery, fertilizers, fuel, seeds, and animal feed. The information sources include official statistics and data from two original surveys.

ACOUSTIC PANEL CHICKEN FEATHER WASTE ENVIRONMENTALLY FRIENDLY

2020 ◽  
Author(s):  
Ansarullah ◽  
Ramli Rahim ◽  
Baharuddin Hamzah ◽  
Asniawaty Kusno ◽  
Muhammad Tayeb
Keyword(s):  
Animal Feed ◽  
Environmentally Friendly ◽  
Selling Price ◽  
Chicken Feather ◽  
Chicken Feathers ◽  
The Road ◽  
Feather Waste ◽  
Chicken Feather Waste ◽  
Almost All ◽  
The Impact

Chicken feathers are the result of waste from slaughterhouses and billions ofkilograms of waste produced by various kinds of poultry processing. This hal is a veryserious problem for the environment because it causes the impact of pollution. Hasmany utilization of chicken feather waste such as making komocen, accessories,upholstery materials, making brackets to the manufacture of animal feed but from theresults of this activity cannot reduce the production of chicken feathers that hiscontinuously increase every year. This is due to the fact that the selling price of chickenmeat has been reached by consumers with middle to upper economic levels. This caneasily be a chicken menu in almost all restaurants and restaurants to the food stalls onthe side of the road. An alternative way of utilizing chicken feathers is to makecomposite materials in the form of panels. Recent studies have shown that the pvacmaterial can be utilized as a mixing and adhesive material with mashed or groundfeathered composites to form a panel that can later be used as an acoustic material.The test results show that the absorption of chicken feathers and pvac glue into panelscan absorb sound well with an absorption coefficient of 0.59, light. This result is veryeconomical so it is worth to be recommended as an acoustic material. Apart from theresults of research methods carried out is one of the environmentally friendly activitiesin particular the handling of waste problems

scholarly journals A Theoretical Analysis of Relations between Pressure Changes along Xylem Vessels and Propagation of Variation Potential in Higher Plants

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 372
Author(s):  
Ekaterina Sukhova ◽  
Elena Akinchits ◽  
Sergey V. Gudkov ◽  
Roman Y. Pishchalnikov ◽  
Vladimir Vodeneev ◽  
...  
Keyword(s):  
Higher Plants ◽  
Initial Point ◽  
Electrical Signal ◽  
Terminal Point ◽  
Hydraulic Pressure ◽  
Long Distance ◽  
Variation Potential ◽  
Damaged Zone ◽  
Pressure Dynamics ◽  
The Impact

Variation potential (VP) is an important long-distance electrical signal in higher plants that is induced by local damages, influences numerous physiological processes, and participates in plant adaptation to stressors. The transmission of increased hydraulic pressure through xylem vessels is the probable mechanism of VP propagation in plants; however, the rates of the pressure transmission and VP propagation can strongly vary. We analyzed this problem on the basis of a simple mathematical model of the pressure distribution along a xylem vessel, which was approximated by a tube with a pressure gradient. It is assumed that the VP is initiated if the integral over pressure is more than a threshold one, taking into account that the pressure is transiently increased in the initial point of the tube and is kept constant in the terminal point. It was shown that this simple model can well describe the parameters of VP propagation in higher plants, including the increase in time before VP initiation and the decrease in the rate of VP propagation with an increase in the distance from the zone of damage. Considering three types of the pressure dynamics, our model predicts that the velocity of VP propagation can be stimulated by an increase in the length of a plant shoot and also depends on pressure dynamics in the damaged zone. Our results theoretically support the hypothesis about the impact of pressure variations in xylem vessels on VP propagation.

scholarly journals Genome-edited Camelina sativa with a unique fatty acid content and its potential impact on ecosystems

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Katharina Kawall
Keyword(s):  
Fatty Acid ◽  
Genome Editing ◽  
Defense Mechanisms ◽  
Fatty Acid Biosynthesis ◽  
Fatty Acid Content ◽  
Camelina Sativa ◽  
Nutritional Composition ◽  
Oilseed Crop ◽  
Biotic And Abiotic Stress ◽  
Multiple Copies

Abstract‘Genome editing’ is intended to accelerate modern plant breeding enabling a much faster and more efficient development of crops with improved traits such as increased yield, altered nutritional composition, as well as resistance to factors of biotic and abiotic stress. These traits are often generated by site-directed nuclease-1 (SDN-1) applications that induce small, targeted changes in the plant genomes. These intended alterations can be combined in a way to generate plants with genomes that are altered on a larger scale than it is possible with conventional breeding techniques. The power and the potential of genome editing comes from its highly effective mode of action being able to generate different allelic combinations of genes, creating, at its most efficient, homozygous gene knockouts. Additionally, multiple copies of functional genes can be targeted all at once. This is especially relevant in polyploid plants such as Camelina sativa which contain complex genomes with multiple chromosome sets. Intended alterations induced by genome editing have potential to unintentionally alter the composition of a plant and/or interfere with its metabolism, e.g., with the biosynthesis of secondary metabolites such as phytohormones or other biomolecules. This could affect diverse defense mechanisms and inter-/intra-specific communication of plants having a direct impact on associated ecosystems. This review focuses on the intended alterations in crops mediated by SDN-1 applications, the generation of novel genotypes and the ecological effects emerging from these intended alterations. Genome editing applications in C. sativa are used to exemplify these issues in a crop with a complex genome. C. sativa is mainly altered in its fatty acid biosynthesis and used as an oilseed crop to produce biofuels.

scholarly journals Theoretical Studies of the Interaction between Screw Surface and Material in the Mixer

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 962
Author(s):  
Andrzej Marczuk ◽  
Vasily Sysuev ◽  
Alexey Aleshkin ◽  
Petr Savinykh ◽  
Nikolay Turubanov ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
High Efficiency ◽  
Animal Feed ◽  
Structural Features ◽  
Power Demand ◽  
Friction Coefficients ◽  
Length Unit ◽  
Mixing Chamber ◽  
Size Of Particles ◽  
The Impact

Mixing is one of the most commonly used processes in food, animal feed, chemical, cosmetic, etc., industries. It is supposed to provide high-quality homogenous, nutritious mixtures. To provide appropriate mixing of materials while maintaining the process high efficiency and low energy consumption it is crucial to explore and describe the material flow caused by the movement of mixing elements and the contact between particles. The process of mixing is also affected by structural features of the machine components and the mixing chamber, speed of mixing, and properties of the mixed materials, such as the size of particles, moisture, friction coefficients. Thus, modeling of the phenomena that accompany the process of mixing using the above-listed parameters is indispensable for appropriate implementation of the process. The paper provides theoretical power calculations that take into account the material speed change, the impact of the material friction coefficient on the screw steel surface and the impact of the friction coefficient on the material, taking into account the loading height of the mixing chamber and the chamber loading value. Dependencies between the mixer power and the product degree of fineness, rotational speed of screw friction coefficients, the number of windings per length unit, and width of the screw tape have been presented on the basis of a developed model. It has been found that power increases along with an increase in the value of these parameters. Verification of the theoretical model indicated consistence of the predicted power demand with the power demand determined in tests performed on a real object for values of the assumed, effective loading, which was 65–75%.

scholarly journals Enhancing the thermostability and activity of uronate dehydrogenase from Agrobacterium tumefaciens LBA4404 by semi-rational engineering

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Hui-Hui Su ◽  
Fei Peng ◽  
Pei Xu ◽  
Xiao-Ling Wu ◽  
Min-Hua Zong ◽  
...  
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Rational Design ◽  
Glucuronic Acid ◽  
Specific Activity ◽  
Value Added ◽  
Catalytic Efficiency ◽  
Site Directed Mutagenesis ◽  
Glucaric Acid ◽  
Triple Mutant ◽  
Pharmaceutical Industries

Abstract Background Glucaric acid, one of the aldaric acids, has been declared a “top value-added chemical from biomass”, and is especially important in the food and pharmaceutical industries. Biocatalytic production of glucaric acid from glucuronic acid is more environmentally friendly, efficient and economical than chemical synthesis. Uronate dehydrogenases (UDHs) are the key enzymes for the preparation of glucaric acid in this way, but the poor thermostability and low activity of UDH limit its industrial application. Therefore, improving the thermostability and activity of UDH, for example by semi-rational design, is a major research goal. Results In the present work, three UDHs were obtained from different Agrobacterium tumefaciens strains. The three UDHs have an approximate molecular weight of 32 kDa and all contain typically conserved UDH motifs. All three UDHs showed optimal activity within a pH range of 6.0–8.5 and at a temperature of 30 °C, but the UDH from A. tumefaciens (At) LBA4404 had a better catalytic efficiency than the other two UDHs (800 vs 600 and 530 s−1 mM−1). To further boost the catalytic performance of the UDH from AtLBA4404, site-directed mutagenesis based on semi-rational design was carried out. An A39P/H99Y/H234K triple mutant showed a 400-fold improvement in half-life at 59 °C, a 5 °C improvement in $$ {\text{T}}_{ 5 0}^{ 1 0} $$ T 50 10 value and a 2.5-fold improvement in specific activity at 30 °C compared to wild-type UDH. Conclusions In this study, we successfully obtained a triple mutant (A39P/H99Y/H234K) with simultaneously enhanced activity and thermostability, which provides a novel alternative for the industrial production of glucaric acid from glucuronic acid.

scholarly journals Active-site serine mutants of the Streptomyces albus G β-lactamase

1991 ◽  
Vol 277 (3) ◽  
pp. 647-652 ◽  
Author(s):  
F Jacob ◽  
B Joris ◽  
J M Frère
Keyword(s):  
Active Site ◽  
Specific Activity ◽  
Site Directed Mutagenesis ◽  
Beta Lactamase ◽  
Wild Type ◽  
Serine Residue ◽  
Wild Type Enzyme ◽  
Ph Values ◽  
Streptomyces Albus ◽  
Small Production

By using site-directed mutagenesis, the active-site serine residue of the Streptomyces albus G beta-lactamase was substituted by alanine and cysteine. Both mutant enzymes were produced in Streptomyces lividans and purified to homogeneity. The cysteine beta-lactamase exhibited a substrate-specificity profile distinct from that of the wild-type enzyme, and its kcat./Km values at pH 7 were never higher than 0.1% of that of the serine enzyme. Unlike the wild-type enzyme, the activity of the mutant increased at acidic pH values. Surprisingly, the alanine mutant exhibited a weak but specific activity for benzylpenicillin and ampicillin. In addition, a very small production of wild-type enzyme, probably due to mistranslation, was detected, but that activity could be selectively eliminated. Both mutant enzymes were nearly as thermostable as the wild-type.

Sign in / Sign up

Export Citation Format

Share Document