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Full-Text Articles in Biomedical Engineering and Bioengineering

Analyzing Drug Release Kinetics From Water-Soluble Polymers, Sean M. Kelly, Arun K. Upadhyay, Akash Mitra, Balaji Narasimhan Feb 2019

Analyzing Drug Release Kinetics From Water-Soluble Polymers, Sean M. Kelly, Arun K. Upadhyay, Akash Mitra, Balaji Narasimhan

Chemical and Biological Engineering Publications

The ability to develop predictive mathematical models of therapeutic release from pharmaceutical formulations has enormous potential to enhance our understanding of such systems and improve the controlled release of the payload. The current work describes the development and testing of a one-dimensional model of drug transport from amorphous, swelling/dissolving polymers. Model parameters such as the diffusivities of water and drug, the initial loading of the drug, the polymer dissolution rate, drug-polymer interactions, and the tablet thickness were varied, demonstrating the ability to tune the release to be controlled by either drug diffusion or polymer chain disentanglement. In addition, predictions ...


Development Of Gelatin And Graphene-Based Nerve Regeneration Conduits Using 3d Printing Strategies For Electrical Transdifferentiation Of Mesenchymal Stem Cells, Metin Uz, Maxsam Donta, Meryem Mededovic, Donald S. Sakaguchi, Surya Mallapragada Feb 2019

Development Of Gelatin And Graphene-Based Nerve Regeneration Conduits Using 3d Printing Strategies For Electrical Transdifferentiation Of Mesenchymal Stem Cells, Metin Uz, Maxsam Donta, Meryem Mededovic, Donald S. Sakaguchi, Surya Mallapragada

Chemical and Biological Engineering Publications

In this study, gelatin and graphene-based nerve regeneration conduits/scaffolds possessing tailored 3D microstructures and mechanical properties were fabricated using 3D printing. The effect of 3D conduit microstructure and mechanical properties along with the applied electrical stimuli on mesenchymal stem cell (MSCs) behavior and transdifferentiation into Schwann cell (SC)-like phenotypes were investigated. The results indicated that the gelatin conduits/scaffolds had favorable 3D microstructural and mechanical properties for MSC attachment and growth. Immunocytochemistry results demonstrated that the application of electrical stimuli through the conductive graphene within the gelatin-based 3D microstructure had a profound effect on the differentiation of MSCs ...


Transfer Of Assembled Collagen Fibrils To Flexible Substrates For Mechanically Tunable Contact Guidance Cues, Juan Wang, Joseph Koelbl, Anuraag Boddupalli, Zhiqi Yao, Kaitlin M. Bratlie, Ian C. Schneider Oct 2018

Transfer Of Assembled Collagen Fibrils To Flexible Substrates For Mechanically Tunable Contact Guidance Cues, Juan Wang, Joseph Koelbl, Anuraag Boddupalli, Zhiqi Yao, Kaitlin M. Bratlie, Ian C. Schneider

Chemical and Biological Engineering Publications

Contact guidance or bidirectional migration along aligned fibers modulates many physiological and pathological processes such as wound healing and cancer invasion. Aligned 2D collagen fibrils epitaxially grown on mica substrates replicate many features of contact guidance seen in aligned 3D collagen fiber networks. However, these 2D collagen self-assembled substrates are difficult to image through, do not have known or tunable mechanical properties and cells degrade and mechanically detach collagen fibrils from the surface, leading to an inability to assess contact guidance over long times. Here, we describe the transfer of aligned collagen fibrils from mica substrates to three different functionalized ...


Microtissue Size And Cell-Cell Communication Modulate Cell Migration In Arrayed 3d Collagen Gels, Jacob A. M. Nuhn, Shenmin Gong, Xiangchen Che, Long Que, Ian C. Schneider Sep 2018

Microtissue Size And Cell-Cell Communication Modulate Cell Migration In Arrayed 3d Collagen Gels, Jacob A. M. Nuhn, Shenmin Gong, Xiangchen Che, Long Que, Ian C. Schneider

Chemical and Biological Engineering Publications

Cells communicate through the extracellular matrix (ECM) in many physiological and pathological processes. This is particularly important during cell migration, where cell communication can alter both the speed and the direction of migration. However, most cell culture systems operate with large volumes relative to cell numbers, creating low cell densities and diluting factors that mediate cell communication. Furthermore, they lack the ability to isolate single cells or small groups of cells. Droplet forming devices allow for an ability to embed single or small groups of cells into small volume segregated 3D environments, increasing the cell density to physiological levels. In ...


Direct Expression Of Active Human Tissue Inhibitors Of Metalloproteinases By Periplasmic Secretion In Escherichia Coli, Ki Baek Lee, Dong Hyun Nam, Jacob A. M. Nuhn, Juan Wang, Ian C. Schneider, Xin Ge Apr 2017

Direct Expression Of Active Human Tissue Inhibitors Of Metalloproteinases By Periplasmic Secretion In Escherichia Coli, Ki Baek Lee, Dong Hyun Nam, Jacob A. M. Nuhn, Juan Wang, Ian C. Schneider, Xin Ge

Chemical and Biological Engineering Publications

Background

As regulators of multifunctional metalloproteinases including MMP, ADAM and ADAMTS families, tissue inhibitors of metalloproteinases (TIMPs) play a pivotal role in extracellular matrix remodeling, which is involved in a wide variety of physiological processes. Since abnormal metalloproteinase activities are related to numerous diseases such as arthritis, cancer, atherosclerosis, and neurological disorders, TIMPs and their engineered mutants hold therapeutic potential and thus have been extensively studied. Traditional productions of functional TIMPs and their N-terminal inhibitory domains (N-TIMPs) rely on costly and time-consuming insect and mammalian cell systems, or tedious and inefficient refolding from denatured inclusion bodies. The later process is ...


Epitaxially Grown Collagen Fibrils Reveal Diversity In Contact Guidance Behavior Among Cancer Cells, Juan Wang, Joseph W. Petefish, Andrew C. Hillier, Ian C. Schneider Jan 2015

Epitaxially Grown Collagen Fibrils Reveal Diversity In Contact Guidance Behavior Among Cancer Cells, Juan Wang, Joseph W. Petefish, Andrew C. Hillier, Ian C. Schneider

Chemical and Biological Engineering Publications

Invasion of cancer cells into the surrounding tissue is an important step during cancer progression and is driven by cell migration. Cell migration can be random, but often it is directed by various cues such as aligned fibers composed of extracellular matrix (ECM), a process called contact guidance. During contact guidance, aligned fibers bias migration along the long axis of the fibers. These aligned fibers of ECM are commonly composed of type I collagen, an abundant structural protein around tumors. In this paper, we epitaxially grew several different patterns of organized type I collagen on mica and compared the morphology ...


Cellular Contractility And Extracellular Matrix Stiffness Regulate Matrix Metalloproteinase Activity In Pancreatic Cancer Cells, Amanda Haage, Ian C. Schneider Aug 2014

Cellular Contractility And Extracellular Matrix Stiffness Regulate Matrix Metalloproteinase Activity In Pancreatic Cancer Cells, Amanda Haage, Ian C. Schneider

Chemical and Biological Engineering Publications

The pathogenesis of cancer is often driven by local invasion and metastasis. Recently, mechanical properties of the tumor microenvironment have been identified as potent regulators of invasion and metastasis, while matrix metalloproteinases (MMPs) are classically known as significant enhancers of cancer cell migration and invasion. Here we have been able to sensitively measure MMP activity changes in response to specific extracellular matrix (ECM) environments and cell contractility states. A pancreatic cancer cell line, Panc-1 cells, up-regulate MMP activities between 3- and 10- fold with increased cell contractility. Conversely, they down-regulate MMP activities when contractility is blocked to levels seen with ...


The Number Of Lines A Cell Contacts And Cell Contractility Drive The Efficiency Of Contact Guidance, Nicholas R. Romsey, Yue Hou, Laura L. Rodriguez, Ian C. Schneider Mar 2014

The Number Of Lines A Cell Contacts And Cell Contractility Drive The Efficiency Of Contact Guidance, Nicholas R. Romsey, Yue Hou, Laura L. Rodriguez, Ian C. Schneider

Chemical and Biological Engineering Publications

Cell migration is an important biological function that impacts many physiological and pathological processes. Often migration is directed along various densities of aligned fibers of collagen, a process called contact guidance. However, cells adhere to other components in the extracellular matrix, possibly affecting migrational behavior. Additionally, changes in intracellular contractility are well known to affect random migration, but its effect on contact guidance is less known. This study examines differences in directed migration in response to variations in the spacing of collagen, non-specific background adhesion strength and myosin II-mediated contractility. Collagen was microcontact printed onto glass substrates and timelapse live-cell ...


A Systems Approach To Designing Next Generation Vaccines: Combining α-Galactose Modified Antigens With Nanoparticle Platforms, Yashdeep Phanse, Brenda Rocio Carrillo-Conde, Amanda Ellen Ramer-Tait, Scott Broderick, Chang Sun Kong, Krishna Rajan, Ramon Flick, Robert B. Mandell, Balaji Narasimhan, Michael J. Wannemuehler Jan 2014

A Systems Approach To Designing Next Generation Vaccines: Combining α-Galactose Modified Antigens With Nanoparticle Platforms, Yashdeep Phanse, Brenda Rocio Carrillo-Conde, Amanda Ellen Ramer-Tait, Scott Broderick, Chang Sun Kong, Krishna Rajan, Ramon Flick, Robert B. Mandell, Balaji Narasimhan, Michael J. Wannemuehler

Chemical and Biological Engineering Publications

Innovative vaccine platforms are needed to develop effective countermeasures against emerging and re-emerging diseases. These platforms should direct antigen internalization by antigen presenting cells and promote immunogenic responses. This work describes an innovative systems approach combining two novel platforms, αGalactose (αGal)-modification of antigens and amphiphilic polyanhydride nanoparticles as vaccine delivery vehicles, to rationally design vaccine formulations. Regimens comprising soluble αGal-modified antigen and nanoparticle-encapsulated unmodified antigen induced a high titer, high avidity antibody response with broader epitope recognition of antigenic peptides than other regimen. Proliferation of antigen-specific CD4 + T cells was also enhanced compared to a traditional ...


Collagen Attachment To The Substrate Controls Cell Clustering Through Migration, Yue Hou, Laura L. Rodriguez, Juan Wang, Ian C. Schneider Jan 2014

Collagen Attachment To The Substrate Controls Cell Clustering Through Migration, Yue Hou, Laura L. Rodriguez, Juan Wang, Ian C. Schneider

Chemical and Biological Engineering Publications

Cell clustering and scattering play important roles in cancer progression and tissue engineering. While the extracellular matrix (ECM) is known to control cell clustering, much of the quantitative work has focused on the analysis of clustering between cells with strong cell-cell junctions. Much less is known about how the ECM regulates cells with weak cell-cell contact. Clustering characteristics were quantified in rat adenocarcinoma cells, which form clusters on physically adsorbed collagen substrates, but not on covalently attached collagen substrates. Covalently attaching collagen inhibited desorption of collagen from the surface. While changes in proliferation rate could not explain differences seen in ...


Understanding Biocatalyst Inhibition By Carboxylic Acids, Laura R. Jarboe, Liam Royce, Ping Liu Sep 2013

Understanding Biocatalyst Inhibition By Carboxylic Acids, Laura R. Jarboe, Liam Royce, Ping Liu

Chemical and Biological Engineering Publications

Carboxylic acids are an attractive biorenewable chemical in terms of their flexibility and usage as precursors for a variety of industrial chemicals. It has been demonstrated that such carboxylic acids can be fermentatively produced using engineered microbes, such as Escherichia coli andSaccharomyces cerevisiae. However, like many other attractive biorenewable fuels and chemicals, carboxylic acids become inhibitory to these microbes at concentrations below the desired yield and titer. In fact, their potency as microbial inhibitors is highlighted by the fact that many of these carboxylic acids are routinely used as food preservatives. This review highlights the current knowledge regarding the ...


Substrate Binding By The Catalytic Domain And Carbohydrate Binding Module Of Ruminococcus Flavefaciens Fd-1 Xyloglucanase/ Endoglucanase, Christopher D. Warner, Gulden Camci-Unal, Nicola L.B. Pohl, Clark Ford, Peter J. Reilly Jan 2013

Substrate Binding By The Catalytic Domain And Carbohydrate Binding Module Of Ruminococcus Flavefaciens Fd-1 Xyloglucanase/ Endoglucanase, Christopher D. Warner, Gulden Camci-Unal, Nicola L.B. Pohl, Clark Ford, Peter J. Reilly

Chemical and Biological Engineering Publications

Binding and thermodynamic properties of a carbohydrate binding module (CBM) and a glycoside hydrolase family 44 xyloglucanase/endoglucanase catalytic domain (CD) fromRuminococcus flavefaciens, both when separate and when linked to each other, have been quantified when binding various β-1,4-linked glucans and xylans. The three constructs bind cellotetraose, cellopentaose, and cellohexaose with association constants that increase with chain length. The CBM does not bind xylotetraose, xylopentaose, or xylohexaose. The CD appears to bind carboxymethylcellulose (CMC) and xylan only weakly, while the CBM and the CD/CBM bind them much more strongly than they bind the cellooligosaccharides. CMC is bound ...


The Orca2 Transcription Factor Plays A Key Role In Regulation Of The Terpenoid Indole Alkaloid Pathway, Chun Yao Li, Alex L. Leopold, Guy W. Sander, Jacqueline V. Shanks, Le Zhao, Susan I. Gibson Jan 2013

The Orca2 Transcription Factor Plays A Key Role In Regulation Of The Terpenoid Indole Alkaloid Pathway, Chun Yao Li, Alex L. Leopold, Guy W. Sander, Jacqueline V. Shanks, Le Zhao, Susan I. Gibson

Chemical and Biological Engineering Publications

Background: The terpenoid indole alkaloid (TIA) pathway leads to the production of pharmaceutically important drugs, such as the anticancer compounds vinblastine and vincristine. Unfortunately, these drugs are produced in trace amounts, causing them to be very costly. To increase production of these drugs, an improved understanding of the TIA regulatory pathway is needed. Towards this end, transgenic Catharanthus roseus hairy roots that overexpress the ORCA2 TIA transcriptional activator were generated and characterized.Results: Transcriptional profiling experiments revealed that overexpression of ORCA2 results in altered expression of key genes from the indole and terpenoid pathways, which produce precursors for the TIA ...


Genome Sequence Of The Psychrophilic Deep-Sea Bacterium Moritella Marina Mp-1 (Atcc 15381), Kumar Babu Kautharapu, Laura R. Jarboe Nov 2012

Genome Sequence Of The Psychrophilic Deep-Sea Bacterium Moritella Marina Mp-1 (Atcc 15381), Kumar Babu Kautharapu, Laura R. Jarboe

Chemical and Biological Engineering Publications

Moritella marina MP-1 is a bacterial species known for its production of docosahexaenoic acid. We present the draft genome sequence of the type strainMoritella marina MP-1 (ATCC 15381), having 4,636,778 bp with a G+C content of 40.5% and consisting of 83 contigs.


Optimization Of Enzyme Parameters For Fermentative Production Of Biorenewable Fuels And Chemicals, Laura R. Jarboe, Ping Liu, Kumar Babu Kautharapu, Lonnie O. Ingram Oct 2012

Optimization Of Enzyme Parameters For Fermentative Production Of Biorenewable Fuels And Chemicals, Laura R. Jarboe, Ping Liu, Kumar Babu Kautharapu, Lonnie O. Ingram

Chemical and Biological Engineering Publications

Microbial biocatalysts such as Escherichia coli and Saccharomyces cerevisiae have been extensively subjected to Metabolic Engineering for the fermentative production of biorenewable fuels and chemicals. This often entails the introduction of new enzymes, deletion of unwanted enzymes and efforts to fine-tune enzyme abundance in order to attain the desired strain performance. Enzyme performance can be quantitatively described in terms of the Michaelis-Menten type parameters Km, turnover number kcat and Ki, which roughly describe the affinity of an enzyme for its substrate, the speed of a reaction and the enzyme sensitivity to inhibition by regulatory molecules. Here we describe examples of ...


Mixed-Surface, Lipid-Tethered Quantum Dots For Targeting Cells And Tissues, Yanjie Zhang, Amanda Haage, Elizabeth M. Whitley, Ian C. Schneider, Aaron R. Clapp Jun 2012

Mixed-Surface, Lipid-Tethered Quantum Dots For Targeting Cells And Tissues, Yanjie Zhang, Amanda Haage, Elizabeth M. Whitley, Ian C. Schneider, Aaron R. Clapp

Chemical and Biological Engineering Publications

Quantum dots (QDs), with their variable luminescent properties, are rapidly transcending traditional labeling techniques in biological imaging and hold vast potential for biosensing applications. An obstacle in any biosensor development is targeted specificity. Here we report a facile procedure for creating QDs targeted to the cell membrane with the goal of cell-surface protease biosensing. This procedure generates water-soluble QDs with variable coverage of lipid functional groups. The resulting hydrophobicity is quantitatively controlled by the molar ratio of lipids per QD. Appropriate tuning of the hydrophobicity ensures solubility in common aqueous cell culture media and while providing affinity to the lipid ...


Reconstructing Genome-Wide Regulatory Network Of E. Coli Using Transcriptome Data And Predicted Transcription Factor Activities, Yao Fu, Laura R. Jarboe, Julie A. Dickerson Jun 2011

Reconstructing Genome-Wide Regulatory Network Of E. Coli Using Transcriptome Data And Predicted Transcription Factor Activities, Yao Fu, Laura R. Jarboe, Julie A. Dickerson

Chemical and Biological Engineering Publications

Background: Gene regulatory networks play essential roles in living organisms to control growth, keep internal metabolism running and respond to external environmental changes. Understanding the connections and the activity levels of regulators is important for the research of gene regulatory networks. While relevance score based algorithms that reconstruct gene regulatory networks from transcriptome data can infer genome-wide gene regulatory networks, they are unfortunately prone to false positive results. Transcription factor activities (TFAs) quantitatively reflect the ability of the transcription factor to regulate target genes. However, classic relevance score based gene regulatory network reconstruction algorithms use models do not include the ...


Kinetic Characterization Of A Glycoside Hydrolase Family 44 Xyloglucanase/Endoglucanase From Ruminococcus Flavefaciens Fd-1, Christopher D. Warner, Rica M. Go, Carolina García-Salinas, Clark Ford, Peter J. Reilly Jan 2011

Kinetic Characterization Of A Glycoside Hydrolase Family 44 Xyloglucanase/Endoglucanase From Ruminococcus Flavefaciens Fd-1, Christopher D. Warner, Rica M. Go, Carolina García-Salinas, Clark Ford, Peter J. Reilly

Chemical and Biological Engineering Publications

Two forms of Ruminococcus flavefaciens FD-1 endoglucanase B, a member of glycoside hydrolase family 44, one with only a catalytic domain and the other with a catalytic domain and a carbohydrate binding domain (CBM), were produced. Both forms hydrolyzed cellotetraose, cellopentaose, cellohexaose, carboxymethylcellulose (CMC), birchwood and larchwood xylan, xyloglucan, lichenan, and Avicel but not cellobiose, cellotriose, mannan, or pullulan. Addition of the CBM increased catalytic efficiencies on both CMC and birchwood xylan but not on xyloglucan, and it decreased rates of cellopentaose and cellohexaose hydrolysis. Catalytic efficiencies were much higher on xyloglucan than on other polysaccharides. Hydrolysis rates increased with ...


Hybrid Thermochemical Processing: Fermentation Of Pyrolysis-Derived Bio-Oil, Laura R. Jarboe, Zhiyou Wen, Dong Won Choi, Robert C. Brown Jan 2011

Hybrid Thermochemical Processing: Fermentation Of Pyrolysis-Derived Bio-Oil, Laura R. Jarboe, Zhiyou Wen, Dong Won Choi, Robert C. Brown

Chemical and Biological Engineering Publications

Thermochemical processing of biomass by fast pyrolysis provides a nonenzymatic route for depolymerization of biomass into sugars that can be used for the biological production of fuels and chemicals. Fermentative utilization of this bio-oil faces two formidable challenges. First is the fact that most bio-oil-associated sugars are present in the anhydrous form. Metabolic engineering has enabled utilization of the main anhydrosugar, levoglucosan, in workhorse biocatalysts. The second challenge is the fact that bio-oil is rich in microbial inhibitors. Collection of bio-oil in distinct fractions, detoxification of bio-oil prior to fermentation, and increased robustness of the biocatalyst have all proven effective ...


Utilizing Protein-Lean Coproducts From Corn Containing Recombinant Pharmaceutical Proteins For Ethanol Production, Ilankovan Paraman, Lorena Beatriz Moeller, M. Paul Scott, Kan Wang, Charles E. Glatz, Lawrence A. Johnson Jan 2010

Utilizing Protein-Lean Coproducts From Corn Containing Recombinant Pharmaceutical Proteins For Ethanol Production, Ilankovan Paraman, Lorena Beatriz Moeller, M. Paul Scott, Kan Wang, Charles E. Glatz, Lawrence A. Johnson

Chemical and Biological Engineering Publications

Protein-lean fractions of corn (maize) containing recombinant (r) pharmaceutical proteins were evaluated as a potential feedstock to produce fuel ethanol. The levels of residual r-proteins in the coproduct, distillers dry grains with solubles (DDGS), were determined. Transgenic corn lines containing recombinant green fluorescence protein (r-GFP) and a recombinant subunit vaccine of Escherichia coli enterotoxin (r-LTB), primarily expressed in endosperm, and another two corn lines containing recombinant human collagen (r-CIα1) andr-GFP, primarily expressed in germ, were used as model systems. The kernels were either ground and used for fermentation or dry fractionated to recover germ-rich ...


Myosin Ii Activity Regulates Vinculin Recruitment To Focal Adhesions Through Fak-Mediated Paxillin Phosphorylation, Ana M. Pasapera, Ian C. Schneider, Erin Rericha, David D. Schlaepfer, Clare M. Waterman Jan 2010

Myosin Ii Activity Regulates Vinculin Recruitment To Focal Adhesions Through Fak-Mediated Paxillin Phosphorylation, Ana M. Pasapera, Ian C. Schneider, Erin Rericha, David D. Schlaepfer, Clare M. Waterman

Chemical and Biological Engineering Publications

Focal adhesions (FAs) are mechanosensitive adhesion and signaling complexes that grow and change composition in response to myosin II-mediated cytoskeletal tension in a process known as FA maturation. To understand tension-mediated FA maturation, we sought to identify proteins that are recruited to FAs in a myosin II-dependent manner and to examine the mechanism for their myosin II-sensitive FA association. We find that FA recruitment of both the cytoskeletal adapter protein vinculin and the tyrosine kinase FA kinase (FAK) are myosin II and extracellular matrix (ECM) stiffness dependent. Myosin II activity promotes FAK/Src-mediated phosphorylation of paxillin on tyrosines 31 and ...


Tertiary Structure And Characterization Of A Glycoside Hydrolase Family 44 Endoglucanase From Clostridium Acetobutylicum, Christopher D. Warner, Julie A. Hoy, Taran C. Shilling, Michael J. Linnen, Nathaniel D. Ginder, Clark Ford, Richard B. Honzatko, Peter J. Reilly Jan 2010

Tertiary Structure And Characterization Of A Glycoside Hydrolase Family 44 Endoglucanase From Clostridium Acetobutylicum, Christopher D. Warner, Julie A. Hoy, Taran C. Shilling, Michael J. Linnen, Nathaniel D. Ginder, Clark Ford, Richard B. Honzatko, Peter J. Reilly

Chemical and Biological Engineering Publications

A gene encoding a glycoside hydrolase family 44 (GH44) protein from Clostridium acetobutylicum ATCC 824 was synthesized and transformed into Escherichia coli.The previously uncharacterized protein was expressed with a C-terminal His tag and purified by nickel-nitrilotriacetic acid affinity chromatography. Crystallization and X-ray diffraction to a 2.2-Å resolution revealed a triose phosphate isomerase (TIM) barrel-like structure with additional Greek key and β-sandwich folds, similar to other GH44 crystal structures. The enzyme hydrolyzes cellotetraose and larger cellooligosaccharides, yielding an unbalanced product distribution, including some glucose. It attacks carboxymethylcellulose and xylan at approximately the same rates. Its activity on carboxymethylcellulose is ...


Mechanisms Of Aqueous Extraction Of Soybean Oil, K. A. Campbell, Charles E. Glatz Nov 2009

Mechanisms Of Aqueous Extraction Of Soybean Oil, K. A. Campbell, Charles E. Glatz

Chemical and Biological Engineering Publications

Aqueous extraction processing (AEP) of soy is a promising green alternative to hexane extraction processing. To improve AEP oil yields, experiments were conducted to probe the mechanisms of oil release. Microscopy of extruded soy before and after extraction with and without protease indicated that unextracted oil is sequestered in an insoluble matrix of denatured protein and is released by proteolytic digestion of this matrix. In flour from flake, unextracted oil is contained as intact oil bodies in undisrupted cells, or as coalesced oil droplets too large to pass out of the disrupted cellular matrix. Our results suggest that emulsification is ...


Epidermal Growth Factor-Induced Contraction Regulates Paxillin Phosphorylation To Temporally Separate Traction Generation From De-Adhesion, Ian C. Schneider, Cristen K. Hays, Clare M. Waterman Jul 2009

Epidermal Growth Factor-Induced Contraction Regulates Paxillin Phosphorylation To Temporally Separate Traction Generation From De-Adhesion, Ian C. Schneider, Cristen K. Hays, Clare M. Waterman

Chemical and Biological Engineering Publications

Directed cell migration is mediated by cycles of protrusion, adhesion, traction generation on the extracellular matrix and retraction. However, how the events after protrusion are timed, and what dictates their temporal order is completely unknown. We used acute epidermal growth factor (EGF) stimulation of epidermal keratinocytes to initiate the cell migration cycle to study the mechanism of the timing of adhesion, traction generation, and de-adhesion. Using microscopic and biochemical assays, we surprisingly found that at ∼2 min after EGF stimulation protrusion, activation of myosin-II, traction generation, adhesion assembly, and paxillin phosphorylation occurred nearly simultaneously, followed by a 10-min delay during ...


Convergence Of Agriculture And Energy: Iii. Considerations In Biodiesel Production, Jon Van Gerpen, Allan Gray, Brent H. Shanks Jan 2008

Convergence Of Agriculture And Energy: Iii. Considerations In Biodiesel Production, Jon Van Gerpen, Allan Gray, Brent H. Shanks

Chemical and Biological Engineering Publications

Concern about rising prices and unstable sources of petroleum fuels is driving the search for U.S. domestically produced, renewable transportation fuels, such as biodiesel. Federal incentives of up to $1.10 per gallon have been supplemented by additional incentives and mandated biodiesel use in many states. The Renewable Fuel Standard in the Energy Independence and Security Act of 2007 requires the domestic use of 1 billion gallons of biomass-based diesel fuel by 2012, most of which likely will be biodiesel.
U.S. biodiesel production is primarily from soybean oil, but recent high prices have forced many producers to use ...


Crystal Structure And Evolution Of A Prokaryotic Glucoamylase, Alexander E. Aleshin, Ping-Hua Feng, Richard B. Honzatko, Peter J. Reilly Mar 2003

Crystal Structure And Evolution Of A Prokaryotic Glucoamylase, Alexander E. Aleshin, Ping-Hua Feng, Richard B. Honzatko, Peter J. Reilly

Chemical and Biological Engineering Publications

The first crystal structures of a two-domain, prokaryotic glucoamylase were determined to high resolution from the clostridial species Thermoanaerobacterium thermosaccharolyticum with and without acarbose. The N-terminal domain has 18 antiparallel strands arranged in β-sheets of a super-β-sandwich. The C-terminal domain is an (α/α)6 barrel, lacking the peripheral subdomain of eukaryotic glucoamylases. Interdomain contacts are common to all prokaryotic Family GH15 proteins. Domains similar to those of prokaryotic glucoamylases in maltose phosphorylases (Family GH65) and glycoaminoglycan lyases (Family PL8) suggest evolution from a common ancestor. Eukaryotic glucoamylases may have evolved from prokaryotic glucoamylases by the substitution of the N-terminal ...


Starch‐Binding Domain Shuffling In Aspergillus Niger Glucoamylase, Catherine A.G. Cornett, Tsuei-Yun Fang, Peter J. Reilly, Clark Ford Jan 2003

Starch‐Binding Domain Shuffling In Aspergillus Niger Glucoamylase, Catherine A.G. Cornett, Tsuei-Yun Fang, Peter J. Reilly, Clark Ford

Chemical and Biological Engineering Publications

Aspergillus niger glucoamylase (GA) consists mainly of two forms, GAI [from the N‐terminus, catalytic domain + linker + starch‐binding domain (SBD)] and GAII (catalytic domain + linker). These domains were shuffled to make RGAI (SBD + linker + catalytic domain), RGAIΔL (SBD + catalytic domain) and RGAII (linker + catalytic domain), with domains defined by function rather than by tertiary structure. In addition, Paenibacillus macerans cyclomaltodextrin glucanotransferase SBD replaced the closely related A.niger GA SBD to give GAE. Soluble starch hydrolysis rates decreased as RGAII ≈ GAII ≈ GAI > RGAIΔL ≈ RGAI ≈ GAE. Insoluble starch hydrolysis rates were GAI > RGAIΔL > RGAI >> GAE ≈ RGAII > GAII, while insoluble starch ...


Replacement And Deletion Mutations In The Catalytic Domain And Belt Region Of Aspergillus Awamori Glucoamylase To Enhance Thermostability, Hsuan-Liang Liu, Yann Doleyres, Pedro M. Coutinho, Clark Ford, Peter J. Reilly Jan 2000

Replacement And Deletion Mutations In The Catalytic Domain And Belt Region Of Aspergillus Awamori Glucoamylase To Enhance Thermostability, Hsuan-Liang Liu, Yann Doleyres, Pedro M. Coutinho, Clark Ford, Peter J. Reilly

Chemical and Biological Engineering Publications

Three single-residue mutations, Asp71→Asn, Gln409→Pro and Gly447→Ser, two long-to-short loop replacement mutations, Gly23-Ala24-Asp25-Gly26-Ala27-Trp28-Val29-Ser30→Asn-Pro-Pro (23–30 replacement) and Asp297-Ser298-Glu299-Ala300-Val301→Ala-Gly-Ala (297–301 replacement) and one deletion mutation removing Glu439, Thr440 and Ser441 (Δ439–441), all based on amino acid sequence alignments, were made to improve Aspergillus awamori glucoamylase thermostability. The first and second single-residue mutations were designed to introduce a potential N-glycosylation site and to restrict backbone bond rotation, respectively, and therefore to decrease entropy during protein unfolding. The third single-residue mutation was made to decrease flexibility and increase O-glycosylation in the already highly O ...