Production of lactate from carbon fixation by cyanobacteria: development and prospect / 生物工程学报

Lactate is an important industrial chemical and widely used in various industries. In recent years, with the increasing demand for polylactic acid (PLA), the demand for lactate raw materials is also increasing. The contradiction between the high cost and the market demand caused by the heterotrophic production of lactate attracts researchers to seek other favorable solutions. The production of lactate from photosynthetic carbon fixation by cyanobacteria is a potential new raw material supply strategy. Based on the photosynthetic autotrophic cell factory, it can directly produce high optical purity lactate from carbon dioxide on a single platform driven by solar energy. The raw materials are cheap and easy to obtain, the process is simple and controllable, the products are clear and easy to separate, and the double effects of energy saving and emission reduction and production of high value-added products are achieved at the same time, which has important research and application value. This paper reviews the development history of cyanobacteria carbon sequestration to produce lactate, summarizes its research progress and encounters technical difficulties from the aspects of metabolic basis, metabolic engineering strategy, metabolic kinetics analysis and technical application, and prospects the future of this technology.

Kinetics for the Inhibition of Serum Acetylthiocholin Esterase Activity by Some Prepared Phenobarbital Derivatives.

This work addresses the kinetic analysis on the interaction of some prepared Phenobarbital derivatives (A, B, C and D) with human serum acetylcholinesterase. It was found that these compound (A, B and D) does have inhibitory effects at different concentrations (10-4, 10-6, 10-8, 10-10M), and were observed to have elevated inhibition with increasing concentrations(10-10 to 10- 4M) of concentrations for both compounds A and B, elevated inhibition with decrease concentration from 10-4 to 10-10M for D. The effects of each A, B and D were reversible in nature. All of the results for C compound were neglected. Michaelis- Menten constant and maximum velocity for hydrolysis of acetylthiocholine iodide by AChE was determined in control and treated systems. Line weaver- Burk plot and their secondary replots indicated that the nature of inhibition was (competitive at concentration 10-4, non competitive at 10-10 for A), (non competitive at 10-4, competitive at 10-10 for B), (non competitive at 10-4, and uncompetitive at 10-10 for D) respectively. The value of ki was also estimated. The action mechanism of these types of compounds acting as inhibitors to the AChE is suggested.

Aptamer-Based Microcantilever Sensor for O-ethyl S-[2-(diisopropylamino) ethyl] methylphosphonothiolate, Sarin Detection and Kinetic Analysis / 分析化学

A new method for O-ethyl S-[2-( diisopropylamino) ethyl] methylphosphonothiolate ( VX) , sarin detection and its kinetic analysis based on piezoresistive microcantilever aptasensor was developed, where VX, sarin aptamers were immobilized on the microcantilever surface by biotin-avidin binding system. A linear relationship between the response voltage and the concentration of VX in the range of 2-60μg/L was obtained. The linear regression equation was △Ue=0. 886C-1. 039 (n=5, R=0. 984, p<0. 001) and the detection limit was 2μg/L ( S/N≥3 ) . A linear relationship between the response voltage and the concentration of sarin in the range of 10-60 μg/L was obtained, the linear regression equation was △Ue=0. 716C-2. 304 ( n=5, R=0 . 996 , p<0 . 001 ) and the detection limit was 10 μg/L ( S/N≥3 ) . The sensor showed no response for O-butyl methylphosphonochloridate, a structural analog of VX and sarin, which indicated high specificity and good anti-interference ability. On this basis, a reaction kinetic model based on receptor-ligand binding and the relationship with output voltage change was established. Response voltage (△Ue ) and response time( t0 ) were obtained from the fitting equation on different concentrations of VX, sarin fitted well with the measured values.

Thermal behavior and decomposition kinetics of rifampicin polymorphs under isothermal and non-isothermal conditions

The thermal behavior of two polymorphic forms of rifampicin was studied by DSC and TG/DTG. The thermoanalytical results clearly showed the differences between the two crystalline forms. Polymorph I was the most thermally stable form, the DSC curve showed no fusion for this species and the thermal decomposition process occurred around 245 ºC. The DSC curve of polymorph II showed two consecutive events, an endothermic event (Tpeak = 193.9 ºC) and one exothermic event (Tpeak = 209.4 ºC), due to a melting process followed by recrystallization, which was attributed to the conversion of form II to form I. Isothermal and non-isothermal thermogravimetric methods were used to determine the kinetic parameters of the thermal decomposition process. For non-isothermal experiments, the activation energy (Ea) was derived from the plot of Log β vs 1/T, yielding values for polymorph form I and II of 154 and 123 kJ mol-1, respectively. In the isothermal experiments, the Ea was obtained from the plot of lnt vs 1/T at a constant conversion level. The mean values found for form I and form II were 137 and 144 kJ mol-1, respectively.

O comportamento térmico de duas formas polimórficas da rifampicina foi estudado por DSC e TG/DTG. Os resultados termoanalíticos mostraram claramente as diferenças entre as duas formas cristalinas. O polimorfo I é a forma mais estável termicamente, a curva DSC não mostrou a fusão dessa espécie e o processo de decomposição térmica ocorreu próximo a 245 ºC. A curva DSC do Polimorfo II apresentou dois eventos consecutivos, um endotérmico (Tpico = 193,9 ºC) e outro exotérmico (Tpico = 209,4 ºC), devido à fusão seguida de recristalização, a qual foi atribuída à conversão da forma II à forma I. Métodos termogravimétricos isotérmicos e não-isotérmicos foram empregados para determinar os parâmetros cinéticos do processo de decomposição térmica. Para experimentos não-isotérmicos, a energia de ativação (Ea) foi obtida a partir do gráfico de Log β vs 1/T, e os valores 154 e 123 kJ mol-1 foram encontrados, respectivamente, para os polimorfos I e II. Para os experimentos isotérmicos, a Ea foi obtida a partir do gráfico de lnt vs. 1/T a um nível de conversão constante. O valor médio encontrado foi 137 e 144 kJ mol-1, respectivamente, para a forma I e forma II.

Kinetic analysis of in vitro production of wild-type Spodoptera frugiperda nucleopolyhedrovirus

In this study, the kinetic behavior of Sf9 and Sf21 cells used in the production of a baculovirus biopesticide to control the pest of corn Spodoptera frugiperda was analyzed. Kinetic variables such as maximum specific growth rate, cell productivity, mean rate of infection, as well as the mean rate of occlusion body production were determined during the infection of these cell-lines with the extracellular virus of the S. frugiperda nucleopolyhedrovirus (SfMNPV). The Sf9 cell-line resulted in better viral production results (5.0 x 10(8) OB/mL) than the Sf21 cell-line (2.5 x 10(8) OB/mL).

Neste trabalho, analisou-se o comportamento cinético das células Sf9 e Sf21 utilizadas na produção de biopesticida para o controle de Spodoptera frugiperda. Variáveis cinéticas, como velocidade específica máxima de crescimento, produtividade em células, velocidade média de infecção e a velocidade média de produção de OB foram determinadas durante a infecção destas linhagens com o vírus extracelular do nucleopoliedrovirus de S. frugiperda. A linhagem Sf9 resultou em melhores resultados de produção do baculovírus (5 x 10(8) OB/mL), quando comparada à linhagem Sf21 (2,5 x 10(8) OB/mL) e outras linhagens da literatura.

Effects of Heavy Metals in Transport of GABA in Cat Brain Synaptosome

The administration of Aluminium had shown the result of neurofibrillary degeneration in encephalopathy of Alzhheimer's desease and cadmium chloride caused the damage of cells of the cerebral cortex. The neurological signs of chronic manganese intoxication were related to Wilson's disease and Parkinsonism. Subsequently the heavy metals were found to be a neurotoxic agent. The author had studied the effect of Al3+, Cd2+ and Mn2+ on transport of synaptosomal GABA and on synaprosomal Na-K-ATPase activity in cat brain. The results were as follows : 1) Synaptosomal GABA uptake was increased within 10 minutes of the incubation and after that time the uptake was not increased and the increase was entirely inhibited by adding cold 5 mM GABA. 2) Al3+, Cd2+ and Mn2+ inhibited the rates of uptake of synaptosomal GABA in a dose-dependent fashion, particularly in Al3+. It was found that the uptake was not made by irreversible damage of synaptosomal uptake. 3) The effect of Al3+ on synaptosomal GABA uptake had shown the inhibition by mixed type fashion of kinetic analysis. 4) Al3+, Cd2+ and Mn2+ inhibited the rates of uptake of synaptosomal Na-K-ATPase activity in a dose-dependent fashion. The concentrations Al3+, Cd2+ and Mn2+ that would give 50% inhibition(IC50) of synaptosomal Na-K-ATPase activity were 1.1x10(-4), 5.6x10(-3) and 6.3x10(-3) M, respectively. 5) Al3+ had shown the inhibition of synaptosomal GABA uptake and Na-K-ATPase activity. In contrast the rate of 88% inhibition of Na-K-ATPase activity had got the rate of 5% inhibition of GABA uptake. The results suggest that the transport(uptake) os synaptosomal GABA is occured by Na+ and also the heavy metal may inhibit the uptake with another mechanism. And then the heavy metal might have the toxic effect of the inhibition of neurotransmitter transport in nerve cells.

Kinetic Analysis of Serum Creatinine / 昆明医科大学学报

In this paper, we report Kinetic method was used to assess the concentration of human serum creatinine with MONARH 661 auto-centrifugal Analyzer. This method required small sample volumes and it was, rapid, convenient and reliable enough to be useful for routine de- termination. The standard curve of serum creatinine concentration was below 1768.0?mol/L. The recovery rate was 96.9-102%, within-run coefficient of variation was 2.86% and between-run was 4.22%. The major advanta ge of the method is that it can effectively avoid the negative interference from glucose, protein and bilirubin, etc. The reagent compares favorably with I Lco. reagent(X), Y = 0.99X-0.45,r=0.9995.

Kinetic analysis on production of IL-1, IL-6 and TNF? by human monocytes / 中国免疫学杂志

Kinetics of production of IL-1, IL-6 and TNFa induced by endotoxin from human monocytes as well as their relationships were studied using cytokine bioassays and immu nocytochemical staining methods. The results showed that accu mulation of IL-1 ?, IL-6 and TNFa molecules in cytoplasma and their release into supernatants had different kinetic patterns from each others, reflecting the difference in gene activation, transcription, translation and release of these three cytokines. In addition, only part of monocytes synthesize IL-1 ?, IL-6 and TNF?, suggesting the presence of different cytokineproducing monocyte subsets.