Initial Protein Concentration Research Articles

Application of the galactomannan gel from Cassia grandis seeds for biomedical purposes: Study of the incorporation of collagenases and their release profile

The galactomannan-based gel from Cassia grandis seeds was used to incorporate Penicillium sp. UCP 1286 and commercial collagenases. Experiments were carried out according to a 23-full factorial design to identify the most significant parameters for the incorporation process. The pH of the incorporation solution (pHi), stirring time (t), and initial protein concentration in the crude extract (PCi) were selected as the three independent variables, and the efficiency of collagenase incorporation (E) and collagenolytic activity (CA) after 360 min as the responses. pHi and PCi showed positive statistically significant effects on E, while CA was positively influenced by pHi and t, but negatively by PCi. The fungi collagenase was released from the gel following a pseudo-Fickian behavior. Additionally, no <76 % of collagenase was efficiently incorporated into the gel retaining a high CA (32.5–69.8 U/mL). The obtained results for the commercial collagenase (E = 93.88 %, CA = 65.8 U/mL, and n = 0.10) demonstrated a pseudo-Fickian behavior similar to the fungi-collagenase. The results confirm the biotechnological potential of the gel as an efficient matrix for the incorporation of catalytic compounds; additionally, the incorporation of collagenases was achieved by retaining the proteases CA and releasing them in a controlled manner.

Ammonia emissions related to black soldier fly larvae during growth on different diets

Abstract Black soldier fly (Hermetia illucens) is considered a farmed animal. The larvae live in a moist substrate, which leads to a complex interaction with the microbial community. As such the combined metabolism of the insects and that of the microbial community can ultimately lead to all sorts of emissions such as ammonia and greenhouse gases. For ammonia emissions and associated depositions, it is known that this can lead to eutrophication of local ecosystems and the formation of particulate matter which can affect human health. This issue is known for intensive livestock farming where in some Western European countries this has led to specific regulations, for example limited number of livestock per farm, to control ammonia emissions. The production of black soldier fly larvae is a novel activity that could similarly lead to ammonia emissions. This study introduces a new method to quantify ammonia emissions in an industrial setting using an accumulation chamber and validates the findings with a nitrogen mass balance. Additionally, different feed substrates (Gainesville diet, chicken feed, artificial supermarket waste and brewers spent grains) were assessed with varying crude protein concentrations, hypothetically one of the driving factors affecting emissions. Results indicate significant ammonia emissions, the total emissions during larval growth ranged from 2.6 up to 83.6 g N/kg larvae (dry matter basis) and depend strongly on the diet. The rates at which these emissions are produced are negligible during the first three days. In the following days all diets emitted ammonia at a varying rate. The highest observed hourly emission rate for test substrates could be as low as 6.8 mg N/kg initial substrate (dry matter basis) and as high as 306 mg/kg. Different properties of the feed, such as the initial crude protein concentration, but also how the pH changes throughout larval growth, will affect emissions.

Activated carbon from sugarcane bagasse as support for lipase immobilization by physical adsorption technique

Lipases are recognized as the most important group of catalysts in biotechnology. However, utilization of free enzymes is often hampered by the need for more operational stability, high cost, and non-reusability. Most of these obstacles can be solved by lipase immobilization. This work's objective was to evaluate the performance of the activated carbon obtained from sugarcane straw (SAC) as a support for lipase immobilization. Two lipases were immobilized by physical adsorption on SAC: Aspergillus niger 11T53A14 lipase and CalB (lipase B from Candida antarctica, Novozymes). Results revealed that the lipase had been anchored on the activated carbon with the lipase binding efficiency of 89 % (A. niger lipase) and 100 % (CalB) at the optimum experimental conditions (initial protein concentration 0.1 mg mL-1, 0.15 g of SAC, 25 °C, and 120 min). Langmuir isotherm fitted the adsorption equilibrium data of the lipases on SAC. SAC presents a high surface area and protein adsorption capacity. These results show that activated carbon synthesized from the sugarcane straw is a promising support for enzyme immobilization.

In situ Fourier transform infrared-attenuated total reflection spectroscopy and modeling investigation of protein adsorption: Case of expanded bovine serum albumin on titanium dioxide anatase.

The purpose of this experimental and modeling research is to study the pH effect and to determine the surface coverage plus the adsorption constant (Ka) of bovine serum albumin (BSA) protein adsorbed on TiO2 anatase surface, respectively. In situ Fourier transform infrared-attenuated total reflection spectroscopy in a flow-through cell was used to study the BSA adsorption on porous TiO2 anatase films. The experiments were performed in water solution, under different pH values, at a concentration of 10-6 mol/l. Theoretically, we extended the two-state model, based on a system of coupled differential equations, by adding a desorption parameter Kd2, for unfolded state. The model was solved taking into account the adsorption (Ka), desorption (Kd1,2), transformation (Kf) coefficients, and the initial solution protein concentration (C0). The findings clearly illustrated that the solution pH drastically changed the behavior of BSA adsorption, whereas the mathematical analytical solutions allowed us to determine the native state (θ1), the unfolded state (θ2), and the full one (θ) surface coverages. Finally, a good application of the approximated model on the experimental work, expanded BSA adsorbed on TiO2 anatase at pH = 1.7, indicated a value of Ka = (408.36 ± 0.996) × 102 mol-1 l min-1.

Neuro-Behçet’s disease with atypical subcortical nodular lesions: A case report and treatment approach

ABSTRACT Neuro-Behçet’s disease (NB) is a rare complication of Behçet’s disease (BD) characterised by central nervous system involvement. While NB typically presents with brainstem lesions, we report an unusual case of NB in a 27-year-old male with multiple subcortical nodular brain lesions but without brainstem, thalamic, or basal ganglia involvement, making this presentation exceptionally rare. The patient had a prior diagnosis of BD and was HLA-B51 positive. He presented with a sudden loss of consciousness, which was attributed to a seizure. Imaging studies showed low-density areas in the white matter of the bilateral temporal lobes and the right frontoparietal lobe on brain CT. Cerebrospinal fluid examination indicated elevated initial pressure and protein concentration, along with increased interleukin-6. Despite presenting with nodular brain lesions, distinguishing between NB and infectious diseases such as tuberculosis (TB) was challenging, and required brain biopsy revealing vasculitis. However, even with this biopsy result, TB could not be ruled out, so TB was treated at the same time. Treatment with anti-TB drugs and standard steroid therapy initially failed to improve the patient’s condition. However, increasing the steroid dosage considering the increased steroid degradation by rifampicin, including pulse therapy with 2 g of methylprednisolone, followed by 18 mg of betamethasone, led to remission of the nodular brain lesions and resolution of the nasopharyngeal ulcer. This case highlights the diagnostic challenge of differentiating between NB and TB based on imaging alone and the potential efficacy of high-dose steroid therapy in cases of steroid-resistant NB with subcortical nodular brain lesions.

Modelling and optimization of bovine serum albumin adsorption on calcium bentonite using box-behnken experimental design method

The purpose of this study is to investigate and optimize the process parameters for bovine serum albumin (BSA) adsorption onto calcium bentonite (CaB) using the Box-Behnken experimental design method. Calcium bentonite was characterized using FT-IR, SEM, XRD, zeta potential measurements, and Boehm titration methods. The BSA adsorption capacity of calcium bentonite was modelled with respect to pH (2.8, 4.8, and 6.8), temperature (25 °C, 32.5 °C, and 40 °C), and initial protein concentration (0.1–1.2 mg ml−1) using the Box-Behnken experimental design method. The Design Expert 13.0 software was used to optimize the process conditions and obtain three-dimensional response surface graphs. A regression model, which gives the relationship between the process parameters and BSA adsorption capacity, was obtained using Design Expert software. The developed model showed that the most effective parameter on adsorption was the initial protein concentration followed by pH and temperature. The maximum adsorption capacity was obtained about 171 mg/g under optimal conditions (pH 4.8, 40 °C, and 1 mg ml−1 of initial BSA concentration). BSA adsorption onto CaB fit the pseudo-second order kinetic model. This study showed that process parameters for BSA adsorption can be effectively investigated and optimized using the Box-Behnken experimental design method with a fewer number of experiments.

Kinetic characterization of digestive proteinases extracted from the processing waste of South Atlantic fish

In Argentina, the fishing industry is highly developed, producing large quantities of waste products from fish processing which contain digestive enzymes with potential biotechnological uses. Among these enzymes are proteinases that hydrolyze proteins and can convert them into functional ingredients. To use these value-added compounds in industrial processes, kinetic characterization of these proteinases under specific conditions, such as contact time, pH, and temperature, must first be carried out. The objective of the present work was to perform a kinetic characterization of crude extracts of alkaline proteinases from intestine-ceca of Merluccius hubbsi, Percophis brasiliensis, Urophycis brasiliensis, and Cynoscion guatucupa. Results showed that the reached maximum values of A440 depended on both the species analyzed and the initial concentration of azocasein. The maximum concentration of hydrolysis products obtained at long times was proportional to the initial concentration of the target protein. P. brasiliensis was the most suitable tested species to obtain high hydrolysis rates at high azocasein concentrations, and exhibited the highest proteinase activities, so it can be considered a candidate species for future biotechnological applications.

Size-Dependent Protein Adsorption on a Nanoparticle.

This study presents the mechanism of adsorption of a model protein within an electrical double layer (EDL) of a charged silica NP in an aqueous salt medium. In contrast to previous works, the charge regulation model analyzes the surface chemistry and electrostatic charge within the EDL by considering polarization, morphology, topography, and protonation/deprotonation. This model is coupled with the three protein adsorption models, such as Classical Langmuir (CLM), Extended Langmuir (ELM), and Two-State (TSM). By this means, surface curvature, conformational changes, and size- and pH-dependent characteristics of protein adsorption are allowed to be observed together in the present numerical model. For a parametric investigation, ionic concentration and pH of the solution, surface charge density, initial protein concentration, electrostatic charge of the protein, and the diameter of the NP are varied systematically. The validation studies with the experimental data agree well with the literature. The size-dependent protein adsorption is simulated and revealed with the current numerical model. Space charge density, chemistry, and morphology of NP's surface profoundly influence adsorption characteristics.

Biodiesel Production Using Palm Oil with a MOF-Lipase B Biocatalyst from Candida Antarctica: A Kinetic and Thermodynamic Study

This research presents the results of the immobilization of Candida Antarctica Lipase B (CALB) on MOF-199 and ZIF-8 and its use in the production of biodiesel through the transesterification reaction using African Palm Oil (APO). The results show that the highest adsorption capacity, the 26.9 mg·g−1 Lipase, was achieved using ZIF-8 at 45 °C and an initial protein concentration of 1.20 mg·mL−1. The results obtained for the adsorption equilibrium studies allow us to infer that CALB was physically adsorbed on ZIF-8 while chemically adsorbed with MOF-199. It was determined that the adsorption between Lipase and the MOFs under study better fit the Sips isotherm model. The results of the kinetic studies show that adsorption kinetics follow the Elovich model for the two synthesized biocatalysts. This research shows that under the experimental conditions in which the studies were carried out, the adsorption processes are a function of the intraparticle and film diffusion models. According to the results, the prepared biocatalysts showed a high efficiency in the transesterification reaction to produce biodiesel, with methanol as a co-solvent medium. In this work, the catalytic studies for the imidazolate, ZIF-8, presented more catalytic activity when used with CALB. This system presented 95% biodiesel conversion, while the biocatalyst formed by MOF-199 and CALB generated a catalytic conversion percentage of 90%. Although both percentages are high, it should be noted that CALB-MOF-199 presented better reusability, which is due to chemical interactions.

Evaporation dynamics of a sessile milk droplet placed on a hydrophobic surface

A colloidal droplet is an integral part of spray-drying based applications such as food, pharmaceuticals, drug delivery, etc. The complex physico-chemical dynamics determine the final structures obtained in the process. Therefore, a complete understanding of the different forces involved and the evaluation of the governing parameters is crucial to control the final morphologies as desired. The evaporation-induced dynamics are studied in milk droplets placed on hydrophobic substrates under natural drying condition. Experiments were performed systematically by varying the initial concentration of protein (BSA) in the droplets. The results were analyzed using energy-based models. Capillary forces and inter-particle interaction are found to have dominating effects upon the particle deposition in the evaporating droplets. Furthermore, inclusion of protein beyond a threshold initial concentration leads to buckling instability which produces cavitated structures. Maintenance of hydrophobicity for a sufficient amount of time is an important criterion to initiate the buckling instability. Our study provides physical insights into the dynamics involved in desiccating droplets, including the buckling dynamics. These insights have far-reaching implications in spray-based industries.

A biochemical necroptosis model explains cell-type-specific responses to cell death cues

Necroptosis is a form of regulated cell death associated with degenerative disorders, autoimmune and inflammatory diseases, and cancer. To better understand the biochemical mechanisms regulating necroptosis, we constructed a detailed computational model of tumor necrosis factor-induced necroptosis based on known molecular interactions from the literature. Intracellular protein levels, used as model inputs, were quantified using label-free mass spectrometry, and the model was calibrated using Bayesian parameter inference to experimental protein time course data from a well-established necroptosis-executing cell line. The calibrated model reproduced the dynamics of phosphorylated mixed lineage kinase domain-like protein, an established necroptosis reporter. A subsequent dynamical systems analysis identified four distinct modes of necroptosis signal execution, distinguished by rate constant values and the roles of the RIP1 deubiquitinating enzymes A20 and CYLD. In one case, A20 and CYLD both contribute to RIP1 deubiquitination, in another RIP1 deubiquitination is driven exclusively by CYLD, and in two modes either A20 or CYLD acts as the driver with the other enzyme, counterintuitively, inhibiting necroptosis. We also performed sensitivity analyses of initial protein concentrations and rate constants to identify potential targets for modulating necroptosis sensitivity within each mode. We conclude by associating numerous contrasting and, in some cases, counterintuitive experimental results reported in the literature with one or more of the model-predicted modes of necroptosis execution. In all, we demonstrate that a consensus pathway model of tumor necrosis factor-induced necroptosis can provide insights into unresolved controversies regarding the molecular mechanisms driving necroptosis execution in numerous cell types under different experimental conditions.

Ultrafiltration of Black Soldier Fly (Hermetia illucens) and Mealworm (Tenebrio molitor) Protein Concentrates to Enhance Emulsifying and Foaming Properties.

Mealworm, TM (Tenebrio molitor), and black soldier fly, BSF (Hermetia illucens) are of special interest for food and feed applications due to their environmental benefits such as low water and land requirements, low greenhouse gas emissions, and high feed-conversion efficiency. This study assesses the use of ultrafiltration (UF) to fractionate protein concentrates from TM and BSF (TMPC, BSFPC) in order to enhance emulsifying and foaming properties. A 30 kDa regenerated cellulose acetate membrane enabled the separation of concentrate and permeate fractions for both insect proteins from two different initial feed concentrations (10 and 7.5 g/L). Permeate flux and protein transmission behave differently depending on the insect type and the initial concentration; while for TMPC permeate flux increases with a decrease in the initial protein concentration, it is not affected for BSFPC. The existing membrane cleaning protocols are suitable for recovering water flux after UF of insect proteins, enabling membrane re-use. Emulsifying activity is maintained for all the TMPC fractions, but it is significantly lower for the permeate fractions of BSFPC. Foaming properties are maintained for all the UF fractions of BSFPC and the ones from 7.5 g/L TMPC. Acidic solubilization leads to a fraction with enhanced emulsifying capacity and one with higher foaming capacity than the original for BSFPC. This study opens the door to membrane technology for insect protein fractionation, which has not been studied so far and has already provided useful solutions for other animal and plant proteins.

Evaluation of the Biochemical and Functional Characteristic of Stinging catfish, Heteropneustes fossilis Muscle Tissue with Emphasize on Myofibrillar Protein and Collagen

Objectives: To evaluate the physico-chemical and functional characteristics of the stinging catfish muscle tissue during the storage time of 18 hours following the death of the fish. Methods: In the present study, stinging catfish were collected from the paddy fields and streams near Tiruvalla Kerala. Fish were slaughtered immediately and analyzed for changes in pH value, cook loss, expressible water content, water holding capacity, sensory demerit score values, and textural profile and were compared with progress of rigor mortis. Study also evaluated the changes in protein fractions present in the muscle tissue and correlated them with autolytic enzyme activities. Findings: In stinging catfish, the rigor mortis occurred within four hours of storage (78.37 %) at ambient temperature. The post rigor stage was attained after the 6th hour and the K value reached above 60% within the 8th hour which indicates the unacceptable range for consumption. The present study also proved that the stinging catfish is an inosine producer. The initial concentration of sarcoplasmic protein in fish muscle (13.71%) decreased to 7.62% at the end of 18 hours of storage. The muscle tissue myofibrillar protein also showed a decrease from an initial concentration of 44.87% to a final concentration of 18.02%. Protein denaturation was evident with an increase from 39.65% to 73.20% at the end of the storage period. Collagen concentration was found to be reduced (31.85% reduction) after the 18th hour of storage. Pepsin soluble collagen was less susceptible to the activity of collagenase enzyme in the pre-rigor stage, confirming its role in post-rigor muscle softening when compared to acid soluble and insoluble collagen. Novelty: The present work authenticated that post-rigor softening of stinging catfish muscle is typically due to the degradation of pepsin soluble collagen and not reported elsewhere. Additionally, myofibrillar proteins have more influence on total hardness and stiffness than collagen, while cohesiveness is a better function of collagen than myofibrillar protein. These findings make it useful to perceive the process thatinduces softening in catfish and to create effective strategies to prevent it. Keywords: Collagen; Myofibrillar Protein; Adenosine Nucleotides; Autolytic Enzymes; Textural Profile

Factors Regulating Fluid Restitution and Plasma Volume Reduction over the Course of Hemodialysis.

Over the course of hemodialysis, fluid and protein are restituted from the tissue compartment to the circulation compartment through the endothelia. Our previous model analysis on fluid and protein transport during hemodialysis is expanded to account for changes occurring in the tissue. The measured initial and end plasma protein concentration (PPC, Cp and Cp') for six hemodialysis studies are analyzed by this expanded model. The computation results indicate that the total driving pressure to restitute fluid from the tissue to the circulation ranges from 5.4 to 20.3 mmHg. The analysis identifies that the increase in plasma colloidal osmotic pressure (COP) contributes 78 ± 6% of the total driving pressure, the decrease in microvascular blood pressure 32 ± 4%, the increase in the COP of interstitial fluid -6 ± 3%, and the decrease in interstitial fluid pressure -5 ± 2%. Let this ratio (Cp' - Cp)/Cp' be termed the PPC increment. The six HDs can be divided into three groups which are to have these PPC increments 25.7%, 14.5 ± 2.6(SD)% and 8.3%. It is calculated that their correspondent filtration coefficients are 0.43, 1.29 ± 0.28 and 5.93 mL/min/mmHg and the relative reductions in plasma volume (RRPV) -22.1%, -13.1 ± 6% and -9.4%. The large variations in PPC increments and RRPV show the filtration coefficient is a key factor to regulate the hemodialysis process.

Water loss from silicone tubing and effect on protein concentration during drug product manufacturing

Silicone tubing is used in various unit operations during drug product (DP) manufacturing. Hold of protein formulations in silicone tubing over time may have an impact on product quality, particularly protein concentration. This study evaluated the change in protein concentration of a test monoclonal antibody (mAb) formulation over various hold times in silicone tubing as a function of tubing internal diameter (ID) and wall thickness. It was hypothesized that the rate of water diffusion through the semi-permeable membrane is a function of the tubing ID and wall thickness. The weight and protein concentration of various formulation-filled tubings over time was measured. The weight of water lost varied linearly with the change in protein concentration. It was observed to be independent of mAb type, formulation composition, and initial protein concentration for a given tubing ID and wall thickness. The effect of formulation water activity on the water loss rate was investigated. A mechanistic diffusion-based model was developed that predicts the change in tubing weight and therefore protein concentration over various hold times for a given formulation and tubing. Overall, this study suggests that water loss from silicone tubing affects protein concentration and should be monitored during DP process development and manufacturing.

In vitro measurement of concentration of unlabeled protein within a hyaluronic acid matrix.

There are currently more than 560 therapeutic monoclonal antibodies (mAbs) at various stages of research and clinical testing, including candidates for administration by subcutaneous (SC) injection. Preclinical studies based on in vitro measurements of high molecular weight proteins within simulated SC matrices are assisting laboratory studies of interactions of injectable biotherapeutic proteins within the SC environment in relation to bioavailability. We report a new method for directly measuring diffusion of unlabeled, high molecular weight proteins injected into an in vitro matrix that simulates the negatively charged environment of the SC. The matrix consists of 10 mg/ml HA in a repurposed cell culture chamber. The measurement consists of pipetting triplicate 20 μl protein samples into the matrix, placing the chamber in a laboratory scanner, activating tryptophan residues in the protein at 280 nm, and imaging the resulting protein fluorescence at 384 nm over a 0.5-4 h time period thus tracking protein movement. This facile approach enables mapping of protein concentration as a function of time and distance within the matrix, and determination of diffusion coefficients, D, within ±10%. Bovine IgG and BSA gave D = 2.3 ± 0.2*10-7 and 4.6 ± 0.2*10-7 cm2 /s at 24°C, respectively, for initial protein concentrations of 21 mg/mL.

Morphological integrity of insulin amyloid-like aggregates depends on preparation methods and post-production treatments

Protein aggregates are often varying extensively in their morphological characteristics, which may lead to various biological outcomes, such as increased immunogenicity risk. However, isolation of aggregates with a specific morphology within an ensemble is often challenging. To gain vital knowledge on the effects of aggregate characteristics, samples containing a single morphology must be produced by direct control of the aggregation process. Moreover, the formed aggregates need to be in an aqueous solution suitable for biological assays, while keeping their morphology intact. Here we evaluated the dependence of morphology and integrity of amyloid-like fibrils and spherulites on preparation conditions and post-treatment methods. Samples containing either amyloid-like fibrils or spherulites produced from human insulin in acetic acid solutions are dependent on the presence of salt (NaCl). Moreover, mechanical shaking (600 rpm) inhibits spherulite formation, while only affecting the length of the formed fibrils compared to quiescent conditions. Besides shaking, the initial protein concentration in the formulation was found to control fibril length. Surprisingly, exchanging the solution used for aggregate formation to a physiologically relevant buffer, had a striking effect on the morphological integrity of the fibril and spherulite samples. Especially the secondary structure of one of our spherulite samples presented dramatic changes of the aggregated β-sheet content after exchanging the solution, emphasizing the importance of the aggregate stability. These results and considerations have profound implications on the data interpretation and should be implemented in the workflow for both fundamental characterization of aggregates as well as assays for evaluation of their corresponding biological effects.

Protein adsorption on a nanoparticle with a nanostructured surface.

In the present study, the adsorption of a protein on a nanoparticle with a nanostructured surface, which is created using successively patterned Gaussian pillars (GPs), is simulated by considering the charge regulation within the electrical double layer of a silica nanoparticle (NP). Namely, the mathematical models for the adsorption mechanism, such as classical Langmuir model, extended Langmuir model, and two-state model, are coupled with charge regulation model. By this means, size and pH variables are able to included to the calculations. Moreover, free space, surface curvature, and conformational changes are also taken into account. For systematic investigation, the solution's pH, surface charge density, initial protein concentration, electrostatic charge of the protein, and the diameter of the spherical NP are varied. As a result, the vital properties of a nanoparticle, such as protonation/deprotonation, polarization, topography, and morphology, are considered in the current simulations. The surface charge density and surface chemistry change with NP and GP sizes. The present results reveal that the protein adsorption on an NP with a smooth surface reaches a faster complete surface coverage than an NP with a nanostructured surface. Both states of conformational changes are also affected by the presence of the GP.

Immobilization of urease enzyme on chitosan/polyvinyl alcohol electrospun nanofibers

Electrospun nanofibers have gained much attention for enzyme immobilization due to their high surface-to-volume ratio. In this study, urease was immobilized on chitosan/poly(vinyl alcohol) (PVA) nanofibers by both adsorption and crosslinking methods. In order to obtain nanofibers with more desirable properties, solutions with different ratios of chitosan and PVA were electrospun and crosslinked using glutaraldehyde. Comparing SEM images of the nanofibers, before and after immersing them in phosphate buffer, it was shown that higher chitosan content leads to more stable fibers. So, the solution with the chitosan to PVA ratio of 40:60 was used for enzyme immobilization. Then, the effects of initial protein concentration, temperature, incubation time, and method of immobilization were investigated to reach the highest enzyme activity. Under similar immobilization conditions, covalently immobilized urease showed higher activity, compared to uncrosslinked immobilized enzyme. Besides, it retained 30% of its initial activity after 10 times usage. So, this method was chosen for further investigation. Not only the activity of the immobilized enzyme was much higher than the free enzyme in a wide range of pH and temperature, but also stability of the immobilized enzyme was improved. Immobilized urease was then used to remove thiourea which is a toxic compound. Findings indicated 60% hydrolysis of initial thiourea in 12 h. In conclusion, the findings showed that chitosan/PVA nanofibers are suitable candidates for the immobilization of urease.

Phosphatases are predicted to govern prolactin-mediated JAK-STAT signaling in pancreatic beta cells.

Patients with diabetes are unable to produce a sufficient amount of insulin to properly regulate their blood glucose levels. One potential method of treating diabetes is to increase the number of insulin-secreting beta cells in the pancreas to enhance insulin secretion. It is known that during pregnancy, pancreatic beta cells proliferate in response to the pregnancy hormone, prolactin (PRL). Leveraging this proliferative response to PRL may be a strategy to restore endogenous insulin production for patients with diabetes. To investigate this potential treatment, we previously developed a computational model to represent the PRL-mediated JAK-STAT signaling pathway in pancreatic beta cells. Here, we applied the model to identify the importance of particular signaling proteins in shaping the response of a population of beta cells. We simulated a population of 10 000 heterogeneous cells with varying initial protein concentrations responding to PRL stimulation. We used partial least squares regression to analyze the significance and role of each of the varied protein concentrations in producing the response of the cell. Our regression models predict that the concentrations of the cytosolic and nuclear phosphatases strongly influence the response of the cell. The model also predicts that increasing PRL receptor strengthens negative feedback mediated by the inhibitor suppressor of cytokine signaling. These findings reveal biological targets that can potentially be used to modulate the proliferation of pancreatic beta cells to enhance insulin secretion and beta cell regeneration in the context of diabetes.