Decomposition of cell activities revealing the role of the cell cycle in driving biofunctional heterogeneity.

Heterogeneity of cell phenotypes remains a barrier in progressing cell research and a challenge in conquering cancer-related drug resistance. Cell morphology, the most direct property of cell phenotype, evolves along the progression of the cell cycle; meanwhile, cell motility, the dynamic property of cell phenotype, also alters over the cell cycle. However, a quantifiable research understanding the relationship between the cell cycle and cell migration is missing.

The Effect of Z-Ligustilide on the Mobility of Human Glioblastoma T98G Cells.

Z-ligustilide (LIG), an essential oil extract from Radix Angelica sinensis, has broad pharmaceutical applications in treating cardio-vascular diseases and ischemic brain injury. Recently, LIG has been connected to Glioblastoma multiforme (GBM) because of its structural similarity to 3-n-alkyphthalide (NBP), which is specifically cytotoxic to GBM cells. Hence, we investigated LIG's effect on GBM T98G cells.

Optimizing cellulase usage for improved mixing and rheological properties of acid-pretreated sugarcane bagasse.

Consolidation of bioprocessing steps with lignocellulose is limited by hydrolysate toxicity, the fibrous nature of suspensions, and low activity of cellulase enzymes. Combinations of enzyme dose and treatment conditions improved the flow properties and pumping of acid-pretreated sugarcane bagasse slurries (10% dry weight). Low levels of cellulase enzyme (0.

Influence of alternating oxic/anoxic conditions on growth of denitrifying bacteria.

Denitrifying bacteria that are switched from oxic to anoxic conditions can experience diauxic lag, which is the time required for re-synthesis of nitrate reductase and other denitrifying enzymes. Pseudomonas denitrificans were exposed to alternating oxic/anoxic phases in a continuous flow reactor with either 4-h or 8-h anoxic phase lengths, in comparison to a measured diauxic lag of 9.5h following steady-state oxic conditions.

Effect of periplasmic nitrate reductase on diauxic lag of Paracoccus pantotrophus.

Paracoccus pantotrophus expresses two nitrate reductases-membrane bound nitrate reductase (Nar) and periplasmic nitrate reductase (Nap). In growth experiments with two denitrifying species (Paracoccus pantotrophus and Alcaligenes eutrophus) that have both Nap and Nar and two species (Pseudomonas denitrificans and Pseudomonas fluorescens) with Nar only, it was found that diauxic lag is shorter for bacteria that express Nap. In P.

Determination of diauxic lag in continuous culture.

A procedure was developed to characterize diauxic lag of bacteria switching between electron acceptors in continuous culture. In this procedure, a virtual batch growth curve is developed by integrating the time-dependent net specific growth rates of bacteria observed under continuous flow conditions. The length of diauxic lag and the highest net specific growth rate following lag are conveniently estimated from the virtual batch curve.

Estimation of nitrate reductase enzyme parameters in activated sludge using an extended Kalman filter algorithm.

This paper demonstrates an application of the extended Kalman filter to a wastewater plant using real process data to estimate parameters in a semi-mechanistic model. This technique for parameter identification allows a semi-mechanistic model developed for pure cultures to be applied to a mixed culture population where isolation of enzyme kinetic parameters is not practical. This paper demonstrates an application in which a wastewater treatment facility with three physical unit operations and an unusual operating profile is modeled as 11 reactor units with recirculation streams.

Combining metabolic engineering and metabolic evolution to develop nonrecombinant strains of Escherichia coli C that produce succinate and malate.

Derivatives of Escherichia coli C were engineered to produce primarily succinate or malate in mineral salts media using simple fermentations (anaerobic stirred batch with pH control) without the addition of plasmids or foreign genes. This was done by a combination of gene deletions (genetic engineering) and metabolic evolution with over 2,000 generations of growth-based selection. After deletion of the central anaerobic fermentation genes (ldhA, adhE, ackA), the pathway for malate and succinate production remained as the primary route for the regeneration of NAD+.

Effect of carbon substrate on electron acceptor diauxic lag and anoxic maximum specific growth rate in species with and without periplasmic enzyme.

The effect of oxidation state of carbon substrate on the diauxic lag of facultative anaerobic denitrifying bacteria growing aerobically upon switching to anoxic growth was studied. Also studied was the effect on the anoxic maximum specific growth rate. Two pure bacteria cultures were used, Paracoccus pantotrophus, denitrifying bacteria containing a periplasmic nitrate reductase (Nap), and Pseudomonas denitrificans, denitrifying bacteria lacking the periplasmic nitrate reductase.

A simple model for diauxic growth of denitrifying bacteria.

A simple model has been formulated to simulate diauxic growth of denitrifying bacteria. It is capable of fitting the experimental results of batch growth experiments with Pseudomonas denitrificans under various conditions. It successfully predicts the observed lags when a pure culture of this bacterium switches from oxygen to nitrate as terminal electron acceptor.

Structured model for denitrifier diauxic growth.

We present a model for diauxic growth of denitrifying bacteria in which nitrate reductase synthesis kinetics dominate the overall growth kinetics. The model is based on the assumption of the existence of a nitrate respiration operon, thereby linking the rate of nitrate uptake to the activity of nitrate reductase. We show that this approach can model diauxic growth of Pseudomonas denitrificans by conducting experiments in which nitrate reductase activity was measured during both lag and ensuing exponential growth phases.