Toward systematic metabolic engineering based on the analysis of metabolic regulation by the integration of different levels of information

2009 ◽  
Vol 46 (3) ◽  
pp. 235-251 ◽  
Author(s):  
Kazuyuki Shimizu
Keyword(s):  
Metabolic Engineering ◽  
Metabolic Regulation ◽  
Different Levels

scholarly journals Metabolic Regulation Analysis of Ajmalicine Biosynthesis Pathway in Catharanthus roseus (L.) G. Don Suspension Culture Using Nanosensor

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 589
Author(s):  
Ghazala Ambrin ◽  
Hayssam M. Ali ◽  
Altaf Ahmad
Keyword(s):  
Metabolic Engineering ◽  
Cell Lines ◽  
Metabolic Regulation ◽  
Antihypertensive Drugs ◽  
Antioxidant Activities ◽  
Regulatory Gene ◽  
Indole Alkaloid ◽  
Resonance Energy ◽  
Flux Analysis ◽  
Suspension Cells

Ajmalicine is one of the most popular antihypertensive drugs obtained from the root barks of Cathranthus roseus (L.) G. Don and Rauvolfia serpentine (L.) Benth. ex Kurz. It has also potential antimicrobial, cytotoxic, central depressant and antioxidant activities. As the demand for the alkaloid is significantly high, metabolic engineering approaches are being tried to increase its production in both homologous and heterologous systems. The metabolic engineering approach requires knowledge of the metabolic regulation of the alkaloid. For understanding the metabolic regulation, fluxomic analysis is important as it helps in understanding the flux of the alkaloid through the complicated metabolic pathway. The present study was conducted to analyse the flux analysis of the ajmalicine biosynthesis, using a genetically encoded Fluorescent Resonance Energy Transfer FRET-based nanosensor for ajmalicine (FLIP-Ajn). Here, we have silenced six important genes of terpenoid indole alkaloid (TIA), namely G10H, 10HGO, TDC, SLS, STR and SDG, through RNA-mediated gene silencing in different batches of C. roseus suspension cells, generating six silenced cell lines. Monitoring of the ajmalicine level was carried out using FLIP-Ajn in these silenced cell lines, with high spatial and temporal resolution. The study offers the rapid, high throughput real-time measurement of ajmalicine flux in response to the silenced TIA genes, thereby identifying the regulatory gene controlling the alkaloid flux in C. roseus suspension cells. We have reported that the STR gene encoding strictosidine synthase of the TIA pathway could be the regulatory gene of the ajmalicine biosynthesis.

scholarly journals Short-, medium- and long-term metabolic responses of adult ewes submitted to nutritional and β-adrenergic challenges

2019 ◽  
Author(s):  
Eliel González-García ◽  
Moutaz Alhamada ◽  
Nathalie Debus ◽  
Jean-Baptiste Menassol ◽  
Anne Tesnière ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Metabolic Regulation ◽  
Body Condition Score ◽  
Lipolytic Activity ◽  
Tissue Mass ◽  
Adipose Tissue Mass ◽  
Condition Score ◽  
Similar Body ◽  
Different Levels

AbstractBackgroundIn order to maintain homeostasis, ruminants submitted to alternating shortage and refeeding situations manifest switches in metabolic pathways induced by undernutrition and body reserves (BR) replenishment cycles. The objective of this experiment was to study adaptive regulatory mechanisms present during subsequent feeding transition periods and the inherent lipolytic activity of the adipose tissue in individuals with contrasted BR. Three diets containing different levels of energy were offered to 36 mature, dry, non-pregnant Mérinos d’Arles ewes in an experiment lasting 122 days. Ewes were selected with similar body weight (BW), body condition score (BCS) and were allocated into three equivalent treatments according to the plane of nutrition: normally fed (Control); underfed (Under) or overfed (Over). The BW, BCS and individual energy metabolism were monitored. At the end of the experiment, lipolytic activity of adipose tissue was studied through a ß-adrenergic challenge to the same ewes, with body conditions according to the offered diet (Normal, Leans and Fat, respectively).ResultsAnabolic or catabolic responses to energy dietary manipulation were accompanied by synchronised metabolic regulation, leading to contrasting metabolic and BR profiles. Average BW and BCS were higher and lower in Over and Under ewes, respectively. The higher and lower BR variations were observed for Under and Over ewes. Higher plasma non-esterified fatty acids (NEFA) concentrations were accompanied by lower insulin, leptin and glucose. Differences in leptin were consistent with the dietary energy load (Over > Control > Under). After refeeding, a rebound in BW and BCS was observed for the three groups whereas NEFA was drastically reduced in Under ewes. No differences among treatments were detected in NEFA profiles at the end of the study but lipolytic activity responses to the ß - adrenergic challenge were different and coherent with the adipose tissue mass (Fat > Normal > Lean) and, importantly, was also different between ewes from the same group or BR status, thus evidencing diversity among individual adaptive capacities.ConclusionsThe ability of ewes to quickly overcome undernutrition situations by efficiently using their BR was confirmed. There is potential for a simplified ß-adrenergic challenge protocol helping to identify differences in adaptive capacity among individuals.

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Immunoenzymatic demonstration of the simultaneous presence of transferrin, hemopexin and albumin in a same hepatocyte and their ultrastructural localization

1978 ◽  
Vol 36 (2) ◽  
pp. 88-89
Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau
Keyword(s):  
Plasma Proteins ◽  
Rat Hepatocytes ◽  
Ultrastructural Localization ◽  
Carrier Proteins ◽  
Normal Cells ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Monospecific Antisera ◽  
Different Levels

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.

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