scholarly journals Coproduction of 5-Aminovalerate and δ-Valerolactam for the Synthesis of Nylon 5 From L-Lysine in Escherichia coli

2021 ◽  
Vol 9 ◽  
Author(s):  
Jie Cheng ◽  
Wenying Tu ◽  
Zhou Luo ◽  
Li Liang ◽  
Xinghua Gou ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ph Value ◽  
Building Blocks ◽  
Equilibrium Mixture ◽  
Scomber Japonicus ◽  
Molar Yield ◽  
Simultaneous Synthesis ◽  
Biological Methods ◽  
The Cost

The compounds 5-aminovalerate and δ-valerolactam are important building blocks that can be used to synthesize bioplastics. The production of 5-aminovalerate and δ-valerolactam in microorganisms provides an ideal source that reduces the cost. To achieve efficient biobased coproduction of 5-aminovalerate and δ-valerolactam in Escherichia coli, a single biotransformation step from L-lysine was constructed. First, an equilibrium mixture was formed by L-lysine α-oxidase RaiP from Scomber japonicus. In addition, by adjusting the pH and H2O2 concentration, the titers of 5-aminovalerate and δ-valerolactam reached 10.24 and 1.82 g/L from 40 g/L L-lysine HCl at pH 5.0 and 10 mM H2O2, respectively. With the optimized pH value, the δ-valerolactam titer was improved to 6.88 g/L at pH 9.0 with a molar yield of 0.35 mol/mol lysine. The ratio of 5AVA and δ-valerolactam was obviously affected by pH value. The ratio of 5AVA and δ-valerolactam could be obtained in the range of 5.63:1–0.58:1 at pH 5.0–9.0 from the equilibrium mixture. As a result, the simultaneous synthesis of 5-aminovalerate and δ-valerolactam from L-lysine in Escherichia coli is highly promising. To our knowledge, this result constitutes the highest δ-valerolactam titer reported by biological methods. In summary, a commercially implied bioprocess developed for the coproduction of 5-aminovalerate and δ-valerolactam using engineered Escherichia coli.

scholarly journals Karakteristik Minuman Probiotik Sari Ubi Kayu dari Kultur Bakteri Lactobacillus acidophilus dan Streptococcus thermophilus

2020 ◽  
pp. 87-94
Author(s):  
Nunung Yulia ◽  
Adi Wibowo ◽  
Eva Dania Kosasih
Keyword(s):  
Escherichia Coli ◽  
Lactobacillus Acidophilus ◽  
Functional Foods ◽  
Ph Value ◽  
Raw Materials ◽  
Streptococcus Thermophilus ◽  
Physiological Effect ◽  
Raw Material ◽  
Experiment Method ◽  
The Cost

Functional foods are food that consumed, as usual, has a physiological effect and can reduce the effect of chronic disease. One of them is probiotic beverages. Probiotic beverages that have been widely known overtime was produced by a dairy house. This product could have been expensive due to the cost of raw materials. The alternative raw material such as the use of extracted cassava juice may reduce the price of the final product. The aims of this research were to study the effects of culture comparison between characteristics of the probiotic beverage from cassava juice, and get the best culture comparison that produces the best probiotic characteristics of the lactic beverage fermentation from cassava juice. This research applied qualitative experiment method in Lactobacillus acidophilus and Streptococcus thermophiles as an inoculum evaluated. Serial in culture ratio respectively 20:50; 30:50; 40:50; and 50:50. The observed research were pH value, viscosity, total lactic acid bacteria (LAB) and activities test against bacteria Escherichia coli. The result showed that the best culture comparison qualified as probiotics criteria was 50:50. It was having pH value 4,1; viscosity 0,706 g/mL; total LAB 2,1x106 cfu/mL and activity bacteria Escherichia coli was 5,3 mm.

scholarly journals Alleviation of C⋅C Mismatches in DNA by the Escherichia coli Fpg Protein

2021 ◽  
Vol 12 ◽  
Author(s):  
Almaz Nigatu Tesfahun ◽  
Marina Alexeeva ◽  
Miglė Tomkuvienė ◽  
Aysha Arshad ◽  
Prashanna Guragain ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Excision Repair ◽  
Dna Lesions ◽  
Base Pairs ◽  
E Coli ◽  
Thymine Glycol ◽  
Base Excision ◽  
The Cost ◽  
Primary Substrate

DNA polymerase III mis-insertion may, where not corrected by its 3′→ 5′ exonuclease or the mismatch repair (MMR) function, result in all possible non-cognate base pairs in DNA generating base substitutions. The most thermodynamically unstable base pair, the cytosine (C)⋅C mismatch, destabilizes adjacent base pairs, is resistant to correction by MMR in Escherichia coli, and its repair mechanism remains elusive. We present here in vitro evidence that C⋅C mismatch can be processed by base excision repair initiated by the E. coli formamidopyrimidine-DNA glycosylase (Fpg) protein. The kcat for C⋅C is, however, 2.5 to 10 times lower than for its primary substrate 8-oxoguanine (oxo8G)⋅C, but approaches those for 5,6-dihydrothymine (dHT)⋅C and thymine glycol (Tg)⋅C. The KM values are all in the same range, which indicates efficient recognition of C⋅C mismatches in DNA. Fpg activity was also exhibited for the thymine (T)⋅T mismatch and for N4- and/or 5-methylated C opposite C or T, Fpg activity being enabled on a broad spectrum of DNA lesions and mismatches by the flexibility of the active site loop. We hypothesize that Fpg plays a role in resolving C⋅C in particular, but also other pyrimidine⋅pyrimidine mismatches, which increases survival at the cost of some mutagenesis.

scholarly journals Design of Multiple Mailboxes

2020 ◽  
Vol 318 ◽  
pp. 01041
Author(s):  
Athena Baronos ◽  
Odysseas Manoliadis ◽  
Aristeidis Pavlidis
Keyword(s):  
3D Visualization ◽  
Building Blocks ◽  
Design Stage ◽  
Extensive Literature ◽  
3D Design ◽  
3D Cad ◽  
Domestic Use ◽  
The Right ◽  
The Cost ◽  
Apartment Complexes

In today’s world the design of multiple mailboxes comes to cover the evolution of logistics in delivering mail where the postman is not required to visit every user. In this research the 3D visualization is used for the design of multiple mailboxes for domestic use. It concerns the design of mailboxes in ergonomic building blocks and apartment complexes in 3D design so that they can be easily manufactured. Between the advantages of this design will be rapid production of ready-made products production of prototypes that enables testing at the design stage and reduces the time and the cost of production. The design when done with 3D CAD can be manufactured with modern machine tooling methods. In this paper after an extensive Literature Review the postal multiple mailboxes is used as a case study in the use of 3D CAD for 3D printing. A methodology is proposed that enables the examination of prototypes at the design stage according to specifications and allows the manufacturing department of a company to prepare the right tools and begin installing production lines. Conclusively this method gives the advantage of designing the product and supporting the production of scaffolds that can be functionally and ergonomically tested before finalizing the production.

scholarly journals Molecular typing of Escherichia coli O157[ratio ]H7 (H−) isolates from cattle in Japan

1999 ◽  
Vol 122 (2) ◽  
pp. 337-341 ◽  
Author(s):  
M. AKIBA ◽  
T. MASUDA ◽  
T. SAMESHIMA ◽  
K. KATSUDA ◽  
M. NAKAZAWA
Keyword(s):  
Escherichia Coli ◽  
Molecular Typing ◽  
Gel Electrophoresis ◽  
Pulsed Field Gel Electrophoresis ◽  
Escherichia Coli O157 ◽  
Outbreak Strain ◽  
Pulsed Field ◽  
E Coli ◽  
Biological Methods ◽  
Pfge Profiles

A total of 77 Escherichia coli O157[ratio ]H7 (H−) isolates from cattle in Japan were investigated by molecular biological methods. Most of these isolates (43 isolates) possessed the stx2 gene, but not stx1. Fifteen bacteriophage types and 50 pulsed-field gel electrophoresis (PFGE) profiles were observed. One isolate was indistinguishable from the human outbreak strain by these methods. This indicates that cattle must be considered as a possible source of human E. coli O157[ratio ]H7 infection in Japan.

scholarly journals Silver Cation Coordination Study to AsW9 Ligand – A Trilacunar Arsenotungstate Compound

2017 ◽  
Vol 63 (2) ◽  
pp. 70-72
Author(s):  
Lavinia Berta ◽  
Andrei Gâz ◽  
Francisc Boda ◽  
Augustin Curticapean
Keyword(s):  
Graphical Method ◽  
Ph Value ◽  
Building Blocks ◽  
Silver Cation ◽  
Molar Ratio ◽  
Equivalence Point ◽  
Tetrahedral Geometry ◽  
Sandwich Type ◽  
Preliminary Study ◽  
Cation Coordination

Abstract Objective: The main objective of this research is to find the coordination ratio between AsW9 and Ag+, as a preliminary study for synthesizing a new silver-arsenotungstate complex. Material and method: The ligand:cation molar ratio in complexes was determined by conductometric and potentiometric titrations of AsW9 with silver salts: CH3COOAg, AgNO3. Results: The ratio was obtained from the inflexion points of the curves when molar ratio was plotted versus conductivity, or from the equivalence point when silver added volume was plotted versus pH value. Each graphic shows one point of inflexion corresponding to 1:1.54 ratio of AsW9:Ag+. In the same manner, the equivalent volumes determined by graphical method gave the ratio 1:1.53. The spectral results confirmed that a AsW9:Ag+ complex was formed since the ligand absorption maxima values have been changed from 190 nm to 197 nm in the case of using AgNO3 and 196 nm for CH3COOAg corresponding to the W=Od bond, and from 246.5 nm to 274 nm (AgNO3) and 270 nm (CH3COO-Ag+) for the W-Ob,c-W bond. Conclusions: Silver cation exhibit a preference for AsW9 in a ratio of 3 to 2. This ratio can be associated to a sandwich type arrangement, with two trilacunary Keggin building blocks incorporating 3 metal cations in a tetrahedral geometry.

scholarly journals Factors that May Influence the Effectiveness of 4 Specialized Nutritious Foods in the Prevention of Stunting and Wasting in Children Aged 6–23 Months in Burkina Faso

2020 ◽  
Vol 4 (2) ◽  
Author(s):  
Breanne K Langlois ◽  
Ilana R Cliffer ◽  
Laetitia Nikiema ◽  
Devika J Suri ◽  
Franck Garanet ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Burkina Faso ◽  
Storage Conditions ◽  
Random Assignment ◽  
Focus Group Discussions ◽  
Group Discussions ◽  
Supplementary Food ◽  
Household Water ◽  
The Cost ◽  
Depth Interviews

ABSTRACT Background A trial in Burkina Faso compared the cost-effectiveness of 4 specialized nutritious foods (SNFs) used to prevent stunting and wasting in children aged 6–23 mo. Objectives This article explores differences in SNF use that may have influenced effectiveness, specifically in relation to consumption by the recipient child and by any other person (i.e., sharing), other diversion from the recipient child, preparation, storage, and hygiene. Methods Subsamples from a geographically clustered, longitudinal trial with random assignment to Corn Soy Blend Plus with oil (CSB+ w/oil), Corn Soy Whey Blend with oil (CSWB w/oil), Super Cereal Plus (SC+), or ready-to-use supplementary food (RUSF) were selected for in-depth interviews, in-home observations, and focus group discussions. Results Sharing was common in all arms, with the highest reported in SC+ (73%) and highest observed in CSWB w/oil (36%). Some reported giving the ration away (highest in SC+ at 17%) or using it for other purposes (highest in CSWB w/oil at 17%). The recipient child was observed consuming the ration in 49% of households on average (38–60% by arm in CSB+ w/oil and RUSF, respectively). Qualitative reports of bitterness and spoilage emerged in the CSWB w/oil arm. Most observed households (excluding RUSF) did not prepare porridge daily as instructed (35–46% by arm). Household water samples showed either high-risk or unsafe contamination with Escherichia coli (72–78% by arm). Low percentages were observed handwashing (both child and server) before consuming the porridge. Conclusions The SNFs were not prepared or served as intended and diversion from the recipient was common. Storage conditions may have resulted in spoilage of the ration containing whey before reaching recipients. This article provides context about factors that may have influenced the effectiveness of these SNFs. Programming and household use of SNFs are as important as their nutrient composition. This trial was registered at clinicaltrials.gov as NCT02071563.

scholarly journals Chemical synthesis of the pentasaccharide repeating unit of the O-specific polysaccharide from Escherichia coli O132 in the form of its 2-aminoethyl glycoside

2019 ◽  
Vol 15 ◽  
pp. 2563-2568
Author(s):  
Debasish Pal ◽  
Balaram Mukhopadhyay
Keyword(s):  
Escherichia Coli ◽  
Chemical Synthesis ◽  
Building Blocks ◽  
Protecting Group ◽  
E Coli ◽  
Specific Polysaccharide

The total chemical synthesis of the pentasaccharide repeating unit of the O-polysaccharide from E. coli O132 is accomplished in the form of its 2-aminoethyl glycoside. The 2-aminoethyl glycoside is particularly important as it allows further glycoconjugate formation utilizing the terminal amine without affecting the stereochemistry of the reducing end. The target was achieved through a [3 + 2] strategy where the required monosaccharide building blocks are prepared from commercially available sugars through rational protecting group manipulation. The NIS-mediated activation of thioglycosides was used extensively for the glycosylation reactions throughout.

All-in-one silicon photonic polarization processor

Nanophotonics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 2257-2267 ◽  
Author(s):  
Hailong Zhou ◽  
Yuhe Zhao ◽  
Yanxian Wei ◽  
Feng Li ◽  
Jianji Dong ◽  
...  
Keyword(s):  
Large Scale ◽  
Optical Network ◽  
Multiple Input Multiple Output ◽  
Building Blocks ◽  
Phase Shifters ◽  
Single Function ◽  
Gradient Descent Algorithm ◽  
Input Multiple Output ◽  
Polarization Functions ◽  
The Cost

AbstractWith the great developments in optical communication technology and large-scale optical integration technology, it is imperative to realize the traditional functions of polarization processing on an integration platform. Most of the existing polarization devices, such as polarization multiplexers/demultiplexers, polarization controllers, polarization analyzers, etc., perform only a single function. Definitely, integrating all these polarization functions on a chip will increase function flexibility and integration density and also cut the cost. In this article, we demonstrate an all-in-one chip-scale polarization processor based on a linear optical network. The polarization functions can be configured by tuning the array of phase shifters on the chip. We demonstrate multiple polarization processing functions, including those of a multiple-input-multiple-output polarization descrambler, polarization controller, and polarization analyzer, which are the basic building blocks of polarization processing. More functions can be realized by using an additional two-dimensional output grating. A numerical gradient descent algorithm is employed to self-configure and self-optimize these functions. Our demonstration suggests great potential for chip-scale, reconfigurable, and fully programmable photonic polarization processors with the artificial intelligence algorithm.

High Technology Options for Sheep Shearing III: Chemical and Biological Defleecing

1987 ◽  
Vol 16 (2) ◽  
pp. 68-76
Author(s):  
P. R. W. Hudson
Keyword(s):  
High Technology ◽  
Cost Price ◽  
Shearing Mechanism ◽  
Biological Methods ◽  
The Cost ◽  
Harvesting Costs

Two earlier articles have considered the cost-price squeeze facing the Australian woolgrower, and the solutions being sought to reduce wool harvesting costs. The first concentrated on the improvements to existing shearing methods, especially the shearing mechanism itself. The second summarised the progress of a programme aiming to automate shearing. This concluding article considers the research which has been undertaken to evaluate chemical and biological methods of wool harvesting.

scholarly journals Resistance/fitness trade-off is a barrier to the evolution of MarR inactivation mutants in Escherichia coli

2020 ◽  
Vol 76 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Lisa Praski Alzrigat ◽  
Douglas L Huseby ◽  
Gerrit Brandis ◽  
Diarmaid Hughes
Keyword(s):  
Escherichia Coli ◽  
Experimental Evolution ◽  
Efflux Pump ◽  
Drug Susceptibility ◽  
Fitness Cost ◽  
Competitive Growth ◽  
Contributing Factors ◽  
Trade Off ◽  
Compensatory Evolution ◽  
The Cost

Abstract Background Mutations that inactivate MarR reduce susceptibility to ciprofloxacin and competitive growth fitness in Escherichia coli. Both phenotypes are caused by overexpression of the MarA regulon, which includes the AcrAB-TolC drug efflux pump. Objectives We asked whether compensatory evolution could reduce the fitness cost of MarR-inactivating mutations without affecting resistance to ciprofloxacin. Methods The cost of overexpressing the AcrAB-TolC efflux pump was measured independently of MarA overexpression. Experimental evolution of MarR-inactive strains was used to select mutants with increased fitness. The acquired mutations were identified and their effects on drug susceptibility were measured. Results Overexpression of the AcrAB-TolC efflux pump was found not to contribute to the fitness cost of MarA regulon overexpression. Fitness-compensatory mutations were selected in marA and lon. The mutations reduced the level of MarA protein thus reducing expression of the MarA regulon. They restored growth fitness but also reduced resistance to ciprofloxacin. Conclusions The fitness cost caused by overexpression of the MarA regulon has multiple contributing factors. Experimental evolution did not identify any single pump-independent cost factor. Instead, efficient fitness compensation occurred only by mechanisms that reduce MarA concentration, which simultaneously reduce the drug resistance phenotype. This resistance/fitness trade-off is a barrier to the successful spread of MarR inactivation mutations in clinical isolates where growth fitness is essential.

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