Understanding Of Cell Metabolism Research Articles

Determination of the amount of oxygen required for each function in the bacterial cell during phenol biodegradation in wastewater: a unique concept

The goal of this study is to provide more in-depth study into the biodegradation of phenol and to determine the amount of oxygen required for each function in the bacterial cell which is fundamental in understanding of cell metabolism and biology. The total amount of oxygen consumed by bacteria is determined using manometric technique. In the biodegradation of phenol (less than 150 mg/L) the oxygen consumed up to the plateau (the stage associated with the termination of carbon) is found to be composed of three portions, one is used to directly oxidize portion of the substrate to produce energy to allow normal cell functions to sustain life which is estimated to be 50% of the plateau BOD (biochemical oxygen demand), the second portion is to oxidize energy storage intermediate (most probably carbon mono oxide, CO, is oxidized to CO2) to release energy which is then used to power reproduction which is estimated to be 41.75% of the plateau BOD, third portion is incorporated into the produced new cells which is estimated to be 8.25% of the plateau BOD. The correlation coefficient between the initial phenol concentration and the ultimate BOD values is found to be r = 0.9999. This value of correlation coefficient, r, may indicate that microbes are, in a way, estimating the amount of food available and they grow and reproduce accordingly. This article provides a better understanding of cell metabolism and biology. This understanding of cell metabolism may offer better understanding of human cells. The results of this research paves the way for a similar research on human cells where abnormal oxygen uptake may assist in early prediction of cells dysfunction and diseases and may help in early taking the necessary precautions to avoid illness.

Succinic acid modified chitosan hydrogel mediates in-situ bioenergetic remodeling of neural cells for neuronal differentiation and spinal cord injury repair

A primary challenge in spinal cord injury repair is the presence of an energy deficit, exacerbated by the injury itself, thereby intensifying the dilemma of insufficient energy. Hence, we posit a hypothesis suggesting that the adoption of a direct energy-supply material strategy has the potential to enhance in situ cellular energy levels, facilitating the acceleration of neuronal differentiation and axonal elongation. We successfully designed a degradable bioenergetic hydrogel by introducing succinic acid (SA), a key intermediate in tricarboxylic acid (TCA) cycle, into chitosan (CS) as an energy-active unit, which was released in a sustained degradation-mediated fashion once implanted. The degraded energy-active units, after being internalized, increased bioenergetic levels via oxidative phosphorylation (OXPHOS) by facilitating TCA flux, thereby contributing to a at least 1.5-fold increase in the expression levels of neuronal differentiation-related markers in vitro, as well as the enhanced spinal cord injury repair and functional recovery in vivo. Further mechanism analysis demonstrated that the upregulation of the bioenergetic basis had the potential to induce neuronal differentiation through the AMP-activated protein kinase-mammalian target of rapamycin (AMPK-mTOR) axis. Additionally, the adenosine triphosphate (ATP) itself acted as a signaling molecule via the P2X7 receptor, leading to the upregulation of intracellular calcium ion-MAPK signal cascades, ultimately promoting neuronal differentiation. Overall, these findings have the potential to significantly alter our understanding of cell metabolism and energy homeostasis, transforming them from passive observers to critical factors in guiding nerve regeneration, and may have implications for future design of bioenergetic-active materials.

Recent Advances in Single-Cell Metabolomics Based on Mass Spectrometry

Recent Advances in Single-Cell Metabolomics Based on Mass Spectrometry

The Atypical Cadherin FAT1 Limits Mitochondrial Respiration and Proliferation of Vascular Smooth Muscle Cells.

Smooth muscle cells contribute to cardiovascular disease, the leading cause of death worldwide. The capacity of these cells to undergo phenotypic switching in mature arteries of the systemic circulation underlies their pathogenic role in atherosclerosis and restenosis, among other vascular diseases. Growth factors and cytokines, extracellular matrix components, regulation of gene expression, neuronal influences, and mechanical forces contribute to smooth muscle cell phenotypic switching. Comparatively little is known about cell metabolism in this process. Studies of cancer and endothelial cell biology have highlighted the importance of cellular metabolic processes for phenotypic transitions that accompany tumor growth and angiogenesis. However, the understanding of cell metabolism during smooth muscle cell phenotypic modulation is incipient. Studies of the atypical cadherin FAT1, which is strongly upregulated in smooth muscle cells in response to arterial injury, suggest that it has important and distinctive functions in this context, mediating control of both smooth muscle cell mitochondrial metabolism and cell proliferation. Here we review the progress made in understanding how FAT1 affects the smooth muscle cell phenotype, highlighting the significance of FAT1 as a processed protein and unexpected regulator of mitochondrial respiration. These mechanisms suggest how a transmembrane protein may relay signals from the extracellular milieu to mitochondria to control metabolic activity during smooth muscle cell phenotypic switching.

How to Turn On an Ancient Metabolic Enzyme? Add Insulin and Deacetylate.

In the ancient metabolic pathway of glycolysis, phosphoglycerate kinase 1 (PGK1) plays a pivotal role. After a couple of preliminary steps that prime the pump, it is PGK1 that creates the first molecule of ATP from the energy stored in glucose, by swinging a molecule of ADP in close to pick a phosphate off an energetic intermediate. While much is known about transcriptional control of PGK1, relatively little is known about how extant PGK1 is regulated. In a new study in PLOS Biology, Shiwen Wang, Yue Xiong, Dan Ye, Kun-Liang Guan, and colleagues elucidate in detail a regulatory pathway that begins with insulin and ends with removal of an acetyl group on PGK1, opening up the enzyme’s active site to bind ADP (Fig 1). Fig 1 Insulin and HDAC3-mediated deacetylation turn on PGK1. Acetylation is perhaps less well known as a regulatory modification than phosphorylation, but it is a ubiquitous method of changing a protein’s structure and function. PGK1 is acetylated in multiple locations, and the authors showed that inhibiting a family of deacetylases led to a decrease in PGK1 activity, indicating the biochemical relevance of the modification. They identified five highly conserved lysine residues on the protein that could serve as a site of acetyl group attachment, and showed that mutating one, K220, reduced activity by over 80%. Modeling suggested, and experiments confirmed, that an acetyl group attached to this site blocked binding of ADP, thus preventing ATP production. Knockdown of a set of acetyltransferase enzymes, which add acetyl groups, revealed one, KAT9, whose loss decreased PGK1 acetylation and whose overexpression increased it. Conversely, overexpression of the deacetylase HDAC3 decreased PGK1 acetylation, and its depletion increased it. Because of its central role in regulating glucose, the authors tested the effect of insulin on PGK1 acetylation. They found that insulin reduced acetylation at K220, an effect that was accompanied by an increase in enzyme activity. Insulin did not change the expression or activity of KAT9. Nor did it change the expression of HDAC3; instead, it enhanced the association of PGK1 and HDAC3 in a dose-dependent manner, indicating the central importance of deacetylation, and therefore activation, of the enzyme as a rapid response to changing energy needs. How was HDAC3 itself regulated? Its ability to deacetylate PGK1 could be inhibited by mutating a critical serine residue, preventing its phosphorylation, and insulin promoted the phosphorylation of that same site. The fraction of HDAC3 bound to PGK1 was highly phosphorylated, while the free enzyme was not, all suggesting that serine phosphorylation was central to regulation of HDAC3. Previous work had identified phosphoinositide-3-kinase (PI3K) as a regulator of HDAC3; here, inhibiting PI3K prevented HDAC3-PGK1 association, leading to a rise in the acetylation level of PGK1. Inhibition of other participants in the pathway, including the central growth controller mTOR, had a similar effect, preventing the upstream insulin signal from triggering the downstream activation of PGK1. Without normal levels of active PGK1, cells could not consume glucose or make ATP at the proper rate, and they displayed multiple signs of metabolic stress. The identification of this important regulatory modification on a metabolically important enzyme is likely to have several important consequences. A full understanding of cell metabolism is still elusive, but modeling improves with every new discovery. The other (non-ATP) product of PGK1 is 3-phosphoglycerate, critical for producing serine, among other cell building blocks, and the authors also showed that PGK1 is involved, in a way not yet clear, in regulating production of NAPDH, a key source of chemical reducing power for anabolic reactions. Since there are several human disorders involving PGK1 deficiency, the discovery of a way to activate the remaining enzyme may have direct clinical implications.

Growth and metabolic characteristics of CCO cells in static and dynamic cultivation systems

The cultivation of animal cells is of great importance for effective and reasonable bioprocess production of various therapeutic proteins as well as for fundamental laboratory research. The metabolic patterns of animal cells are altered substantially during the actions of establishment of a typical cell line designed for in vitro techniques. Therefore, characterization and understanding of cell metabolism are needed to improve the processes with cultivated animal cells. The channel catfish ovary cell line (CCO) was derived from the ovaries of a juvenile channel catfish some thirty years ago. Since then, it has been used for channel catfish virus vaccine production and related in vitro laboratory research. However there is still no enough data for basal understanding of their metabolism. We report on growth characteristics of CCO cells cultivated in multiwell plates and Wave bioreactor. Specific growth rate of CCO cells in multiwell plates was 0, 0206 h-1. The concentration of glucose in culture media remained unchanged through whole cultivation period. Glutamine was almost completely depleted and ammonia, its major wasteproduct, reached concentration of 2, 3 mM. Amino acid analysis of culture media showed that highly consumed amino acids, besides glutamine, were arginine, serine, and threonine, suggesting that they were main energy source. Cytodex 1 microcarriers were used in order to investigate medium-scale cultivation parameters of CCO cells in the Wave bioreactor. In this cultivation system oxygen transfer and mixing are accomplished by the wave-induced agitation. Micocarrier confluence was reached with cell density of 1, 8 x 10e6 cells/mL and cell growth rate of 0, 0182 h-1. The results proved the feasibility of employed culture conditions for cultivation of CCO cells.

Comparison ofTrichoplusia ni BTI-Tn-5B1-4 (high five™) andSpodoptera frugiperda Sf-9 insect cell line metabolism in suspension cultures

Nutrient utilization and byproduct accumulation were monitored in Spodoptera frugiperda Sf-9 and Trichoplusia ni BTI-Tn-5B1-4 (High Five) cell lines during growth and following viral infection in suspension cultures in order to develop a better understanding of cell metabolism and to acquire information relevant to large scale fed-batch bioreactors. The utilization of glucose, dissolved oxygen, and amino acids were monitored in Sf-9 cell cultures grown in Sf-900 II serum-free medium (SFM) and in High Five cell cultures grown in both Sf-900 II and Express Five SFM. Using the optimal medium for each cell line, i.e., Sf-900 II SFM for Sf-9 cells and Express Five SFM for High Five cells, the cell growth rate, maximum cell density, specific glucose and glutamine utilization rates, and specific alanine production rate were comparable during cell growth. In addition, the expression level of recombinant human tissue plasminogen activator was comparable in the two cell lines on a per cell basis. It was found, however, that lactate and ammonia accumulated in High Five cell cultures, but not in Sf-9 cell cultures. In addition, High Five cells utilized asparagine more rapidly than glutamine, whereas Sf-9 cells consumed only minimal asparagine, and the oxygen utilization rate was significantly higher in High Five cell cultures. It was also found that the medium had a significant effect on High Five cell metabolism, e.g., the specific glucose utilization rate and the specific lactate and alanine production rates were significantly higher in Sf-900 II SFM than in Express Five SFM. In addition, the maximum cell density and specific asparagine utilization rate were significantly higher in Express Five SFM.

Determination of the respiration quotient in mammalian cell culture in bicarbonate buffered media

The determination of the respiration quotient (RQ = CER/OUR) has not been used so far as a tool for understanding animal cell metabolism. This is due to problems in measuring the carbon dioxide evolution rate (CER) rather than the oxygen uptake rate (OUR). The determination of the CER is complicated by the use of bicarbonate in the medium. Using liquid and gas balances we have derived an equation for continuous culture to quantify the amount of CO(2) that comes from the bicarbonate in the feed. Under cell-free conditions, values predicted by this equation agree within 4% with the experimental results. In continuous culture using hybridoma cells, the CO(2) from the feed, as determined by an IR-gas analyzer, was found to represent a significant amount of the total measured CO(2) in the off-gas (50% in a suboptimal, and 30% in high-growth medium). Furthermore, the problem of CO(2) loss from the medium during medium preparation and storage was solved using both a theoretical and an experimental approach. RQ values in continuous culture were evaluated for two different growth media. Small but significant differences in RQ were measured, which were matched by differences in specific antibody rates and other metabolic quotients. In a medium with Primatone RL, an enzymatic hydrolysate of animal cell tissue that causes a more than twofold increase in cell density, the RQ was found to be 1.05, whereas in medium without Primatone RL (but containing amino acids equivalent in composition and concentration to Primatone RL) the RQ was found to be 0.97. We suggest the RQ to be a useful parameter for estimating the physiological state of cells. Its determination could be a suitable tool for both the on-line control of animal cell cultivations and the understanding of cell metabolism.

Veränderungen in der Ultrastruktur des Chondrozyten unter dem Einfluß eines GAG-Peptid-Komplexes

Using an ultrastructural test system (Annefeld, Fassbender, 1983) based on standardised morphometry and statistical evaluation, the authors have studied the influence of a GAG-peptide-complex (Rumalon) on chondrocyte ultrastructure in healthy and damaged articular cartilage of the rat. Evaluation of the data obtained from extensive cell compounds allows for qualitative and quantitative assessment of early changes in the organelle-system of cartilage cells: understanding of cell metabolism is thus greatly enhanced.