Glycolysis and the regulation of glucose transport in Lactococcus lactis spp. lactis in batch and fed-batch culture.
Glycolysis and the regulation of glucose transport in Lactococcus lactis spp. lactis in batch and fed-batch culture.
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糖酵解和乳酸乳酸菌属葡萄糖转运的调节。乳酸乳酸和批处理培养物。
DOI：
10.1186/1475-2859-6-16
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发表时间：
2007-05-24
影响因子：
6.4
通讯作者：
Filiousis, George
中科院分区：
文献类型：
--
作者：
Papagianni, Maria;Avramidis, Nicholaos;Filiousis, George
尽管许多报道涉及乳酸乳球菌中的糖酵解，但关于葡萄糖摄取本身的调节的信息不多。本工作的目的是研究葡萄糖水平对其比摄取速率的影响。pH控制下L.乳酸菌属乳酸菌在葡萄糖（55mM）上的分批培养表明，产物形成是非常纯乳酸的，并且在微需氧条件（5%溶解氧）下获得了葡萄糖上乳酸盐的最高产率。因此，微需氧条件应用于进行的实验中，以研究葡萄糖摄取的调节。的工具glucostat补料分批培养，其中加入葡萄糖在整个运行与葡萄糖浓度范围从13.75至555 mM的葡萄糖浓度适合保持一个稳定的浓度。glucostat实验表明，葡萄糖的浓度影响其特定的摄取速率，因此糖酵解通量，以及发酵模式。在55 mM葡萄糖下获得关键糖酵解酶PFK、PYK和LDH的最高比活性，这是观察到的最高糖酵解通量的区域。在277 mM葡萄糖抑制剂中，糖酵解通量减少55%对应于PFK活性几乎相同的减少，表明这种酶通过葡萄糖效应对通量有一定的控制影响。细胞内代谢物池的测定表明，不能将FBP视为产物形成的直接调节剂，因为在低（13.75 mM）和高（138 mM）葡萄糖水平下获得了几乎相同的浓度，其中葡萄糖摄取速率和糖酵解通量以及发酵模式均不相似（分别为混合酸与纯乳酸）。相反，Glucostat数据显示，在检查条件下，通过糖酵解途径的通量控制在很大程度上存在于途径外的过程中，如ATP消耗反应和葡萄糖转运。提出了一种由细胞能量状态控制的调节机制，L。乳酸可以通过关键酶的变构特性来处理糖酵解通量，其中PFK对控制具有显著影响。
Despite the fact that many reports deal with glycolysis in Lactococcus lactis, there is not much information on the regulation of uptake of glucose itself. The aim of the present work was to investigate the effect of the glucose level on its specific uptake rate. Studies on aeration levels in pH controlled L. lactis spp. lactis batch cultures on glucose (55 mM) showed that product formation is extremely homolactic and the highest yield of lactate on glucose is obtained under microaerobic conditions (5% dissolved oxygen). Microaerobic conditions were therefore applied in experiments carried out to investigate the regulation of the uptake of glucose. The tool of glucostat fed-batch culture was employed, in which glucose was added at a rate suitable to maintain a stable concentration throughout the runs with glucose concentration ranging from 13.75 to 555 mM. The glucostat experiments showed that the concentration of glucose influences its specific uptake rate and consequently the glycolytic flux, as well as the fermentation pattern. The highest specific activities of the key glycolytic enzymes PFK, PYK and the LDH were obtained at 55 mM glucose, the area of the highest observed glycolytic flux. Reduction of the glycolytic flux by 55% in the 277 mM glucostat corresponded to an almost identical reduction in PFK activity, indicating a certain controlling influence of this enzyme on the flux, through the glucose effect. Determination of intracellular metabolites' pools showed that FBP cannot be regarded as a direct regulator of product formation, since almost identical concentrations were obtained at both low (13.75 mM) and high (138 mM) glucose levels, at which neither the glucose uptake rates and the glycolytic flux, nor the fermentation patterns were similar (mixed acids vs homolactic, respectively). Glucostat data showed instead that the control of the flux through the glycolytic pathway under the examined conditions, resides to a large extent in processes outside the pathway, like the ATP consuming reactions and glucose transport. A regulation mechanism is proposed governed by the energy state of the cell by which L. lactis can handle the glycolytic flux through the allosteric properties of key enzymes, with PFK having a significant influence on the control.
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影响因子：
3.2
作者：
Arnau, J;Jorgensen, F;Israelsen, H
通讯作者：
Israelsen, H
影响因子：
64.8
作者：
EVANS, PR;HUDSON, PJ
通讯作者：
HUDSON, PJ
影响因子：
4.4
作者：
FORDYCE, AM;CROW, VL;THOMAS, TD
通讯作者：
THOMAS, TD
DOI：
10.1099/00221287-139-8-1861
发表时间：
1993-08-01
期刊：
JOURNAL OF GENERAL MICROBIOLOGY
影响因子：
--
作者：
LEBLOAS, P;GUILBERT, N;LINDLEY, ND
通讯作者：
LINDLEY, ND
影响因子：
3.2
作者：
LLANOS, RM;HARRIS, CJ;DAVIDSON, BE
通讯作者：
DAVIDSON, BE