Biomedical Engineering and Bioengineering Commons^™

Adjuvant Pluronic F68 Is Compatible With A Plant Root-Colonizing Probiotic, Pseudomonas Chlororaphis O6, Amanda R. Streeter, Anthony Cartwright, Mohammad Zargaran, Anagha Wankhade, Anne J. Anderson, David W. Britt

Biological Engineering Faculty Publications

Plant probiotic bacteria are being increasingly used to maximize both the productivity and quality of field crops. Pseudomonas chlororaphis O6 (PcO6) is a plant root colonizer with probiotic activities. This bacterium produces an array of metabolites, including a group of phenazines that are functional in plant protection. The paper reports responses of PcO6 to a nonionic triblock copolymer surfactant, Pluronic F68. This Pluronic exhibits membrane "healing" activity and improves cryopreservation recovery in eukaryotic cells. The product is FDA-approved and is applied as an adjuvant in formulations used in agriculture, medicine, and biotechnology. Growth of PcO6 on …

Microbial Glycosylation Of Antitubercular Agent Chlorflavonin, Jie Ren, Jixun Zhan

Biological Engineering Faculty Publications

Flavonoids have shown health-benefiting properties, such as antioxidative and anti-inflammatory activities, and are commonly used as nutraceuticals and pharmaceuticals. Although flavonoids are predominantly identified from plants, several filamentous fungal species have also been reported to produce bioactive flavonoids, including chlorflavonin from Aspergillus candidus, a novel halogenated flavonoid with potent antifungal and antitubercular (anti-TB) activities. Unfortunately, the low water-solubility of this molecule may hinder its bioavailability. Glycosylation is an effective method to enhance the polarity of natural products and alter their physicochemical properties. This work focuses on the development of novel water-soluble chlorflavonin derivatives to combat the threat of drug-resistant …

Environmentally Friendly New Catalyst Using Waste Alkaline Solution From Aluminum Production For The Synthesis Of Biodiesel In Aqueous Medium, Sandro L. Barbosa, David Lee Nelson, Lucas Paconio, Moises Pedro, Wallans Torres Pio Dos Santos, Alexandre P. Wentx, Fernando L. P. Pessoa, Foster A. Agblevor, Daniel A. Bortoleto, Maria B. De Freitas-Marques, Lucas D. Zanatta

Biological Engineering Faculty Publications

Red mud (RM) is composed of a waste alkaline solution (pH = 13.3) obtained from the production of alumina. It contains high concentrations of hematite (Fe₂O₃), goethite (FeOOH), gibbsite [Al(OH)₃], a boehmite (AlOOH), anatase (Tetragonal–TiO₂), rutile (Ditetragonal dipyramidal–TiO₂), hydrogarnets [Ca₃Al₂(SiO₄)_3-x(OH)_4x], quartz (SiO₂), and perovskite (CaTiO₃). It was shown to be an excellent catalytic mixture for biodiesel production. To demonstrate the value of RM, an environmentally friendly process of transesterification in aqueous medium using waste cooking oil …

Engineered Production Of Bioactive Polyphenolic O-Glycosides, Jie Ren, Caleb Don Barton, Jixun Zhan

Biological Engineering Faculty Publications

Polyphenolic compounds (such as quercetin and resveratrol) possess potential medicinal values due to their various bioactivities, but poor water solubility hinders their health benefits to humankind. Glycosylation is a well-known post-modification method to biosynthesize natural product glycosides with improved hydrophilicity. Glycosylation has profound effects on decreasing toxicity, increasing bioavailability and stability, together with changing bioactivity of polyphenolic compounds. Therefore, polyphenolic glycosides can be used as food additives, therapeutics, and nutraceuticals. Engineered biosynthesis provides an environmentally friendly and cost-effective approach to generate polyphenolic glycosides through the use of various glycosyltransferases (GTs) and sugar biosynthetic enzymes. GTs transfer the sugar moieties from …

Identification Of A Novel Glucuronyltransferase From Streptomyces Chromofuscus Atcc 49982 For Patural Product Glucuronidation, Jie Ren, Caleb Don Barton, Kathryn Eternity Sorenson, Jixun Zhan

Biological Engineering Faculty Publications

Glycosylation is an effective way to increase the polarity of natural products. UDP-glucuronyltransferases (UGTs) are commonly observed and extensively studied in phase II drug metabolism. However, UGTs in microorganisms are not well studied, which hampered the utilization of this type of enzyme in microbial glucuronidation of natural products. Screening of five actinomycete strains showed that Streptomyces chromofuscus ATCC 49982 can convert diverse plant polyphenols into more polar products, which were characterized as various glucuronides based on their spectral data. Analysis of the genome of this strain revealed a putative glucuronidation gene cluster that contains a UGT gene (gcaC) …

Assessing Leachable Cytotoxicity Of 3d-Printed Polymers And Facile Detoxification Methods, Venkatakrishnan Rengarajan, Angela Clyde, Jefferson Pontsler, Jonathan Valiente, Adreann Peel, Yu Huang

Biological Engineering Faculty Publications

Additive manufacturing of polymers is gaining momentum in health care industries by providing rapid 3D printing of customizable designs. Yet, little is explored about the cytotoxicity of leachable toxins that the 3D printing process introduced into the final product. We studied three printable materials, which have various mechanical properties and are widely used in stereolithography 3D printing. We evaluated the cytotoxicity of these materials through exposing two fibroblast cell lines (human and mouse derived) to the 3D-printed parts, using overlay indirect contact assays. All the 3D-printed parts were measured toxic to the cells in a leachable manner, with flexible materials …

A Highly Versatile Fungal Glucosyltransferase For Specific Production Of Quercetin-7-O-Β-D-Glucoside And Quercetin-3-O-Β-D-Glucoside In Different Hosts, Jie Ren, Wenzhu Tang, Caleb Don Barton, Owen M. Price, Mark Wayne Mortensen, Alexandra Phillips, Banner Wald, Simon Elgin Hulme, Logan Powell Stanley, Joan Hevel, Jixun Zhan

Biological Engineering Faculty Publications

Glycosylation is an effective way to improve the water solubility of natural products. In this work, a novel glycosyltransferase gene (BbGT) was discovered from Beauveria bassiana ATCC 7159 and heterologously expressed in Escherichia coli. The purified enzyme was functionally characterized through in vitro enzymatic reactions as a UDP-glucosyltransferase, converting quercetin to five monoglucosylated and one diglucosylated products. The optimal pH and temperature for BbGT are 35 ℃ and 8.0, respectively. The activity of BbGT was stimulated by Ca2+, Mg2+, and Mn2+, but inhibited by Zn2+. BbGT enzyme is flexible and can glycosylate a variety of substrates such as curcumin, …

Discovery Of A Novel Analogue Of Fr901533 And The Corresponding Biosynthetic Gene Cluster From Streptosporangium Roseum No. 79089, Fuchao Xu, Yonghong Liang, Jie Ren, Siyuan Wang, Jixun Zhan

Biological Engineering Faculty Publications

FR901533 (1, also known as WS79089B), WS79089A (2), and WS79089C (3) are polycyclic aromatic natural products with promising inhibitory activity to endothelin-converting enzymes. In this work, we isolated five tridecaketide products from Streptosporangium roseum No. 79089, including 1-3, benaphthamycin (4) and a novel FR901533 analogue (5). The structure of 5 was characterized based on spectroscopic data. Compared to the major product 2, the new compound 5 has an additional hydroxyl group at C-12 and an extra methyl group at the 13-OH. The configuration of C-19 of these compounds …

Existing Empirical Kinetic Models In Biochemical Methane Potential (Bmp) Testing, Their Selection And Numerical Solution, Yehor Pererva, Charles D. Miller, Ronald C. Sims

Biological Engineering Faculty Publications

Biochemical Methane Potential (BMP) tests are a crucial part of feasibility studies to estimate energy recovery opportunities from organic wastes and wastewater. Despite the large number of publications dedicated to BMP testing and numerous attempts to standardize procedures, there is no “one size fits all” mathematical model to describe biomethane formation kinetic precisely. Importantly, the kinetics models are utilized for treatability estimation and modeling processes for the purpose of scale-up. A numerical computation approach is a widely used method to determine model coefficients, as a replacement for the previously used linearization approach. However, it requires more information for each model …

Isolation And Selective Glycosylation Of Antisalmonellal Anthraquinones From The Stem Bark Of Morinda Lucida Benth. (Rubiaceae), Napoleon A. Mfonku, James A. Mbah, Norbert Kodjio, Donatien Gatsing, Jixun Zhan

Biological Engineering Faculty Publications

In this work we report the isolation, identification and antibacterial activity of two anthraquinones, 2-hydroxy-1-methoxyanthraquinone (1) and 2,5-dihydroxy-1-methoxy-6-methoxymethylanthraquinone (2), from the stem bark of Morinda lucida. These two natural products were selectively converted into two new glycosylated derivatives, 2-hydroxy-1-methoxyanthraquinone-4′-O-methyl-2-O-β-d-glucopyranoside (3) and 2,5-dihydroxy-1-methoxy-6-methoxymethylanthraquinone-4′-O-methyl-2-O-β-d-glucopyranoside (4) by the filamentous fungus Beauveria bassiana ATCC 7159. Structure elucidation was accomplished based on the 1D and 2D NMR, IR and mass spectra. The glycosylated compounds 3 and 4 showed higher in vitro antibacterial activity against Salmonella enterica subsp. enterica sérovars Typhimurim (MIC of 8 μg/mL each) than the corresponding aglycons 1 and 2 (MIC of …

Acute Mechanical Stress In Primary Porcine Rpe Cells Induces Angiogenic Factor Expression And In Vitro Angiogenesis, Farhad Farjood, Amir Ahmadpour, Sassan Ostvar, Elizabeth Vargis

Biological Engineering Faculty Publications

Background

Choroidal neovascularization (CNV) is a major cause of blindness in patients with age-related macular degeneration. CNV is characterized by new blood vessel growth and subretinal fluid accumulation, which results in mechanical pressure on retinal pigment epithelial (RPE) cells. The overexpression of RPE-derived angiogenic factors plays an important role in inducing CNV. In this work, we investigated the effect of mechanical stress on the expression of angiogenic factors in porcine RPE cells and determined the impact of conditioned medium on in-vitro angiogenesis.

Results

The goal of this study was to determine whether low levels of acute mechanical stress during early …

Initial Development Of Corn Seedlings After Seed Priming With Nanoscale Synthetic Zinc Oxide, Michel Esper Neto, David W. Britt, Lorena Moreira Lara, Anthony Cartwright, Rayssa Fernanda De Santos, Tadeu Takeyoshi Inoue, Marcelo Augusto Batista

Biological Engineering Faculty Publications

Nanofertilizers are increasingly explored for sustainable micronutrient delivery in agriculture. Pre-treating seeds with nanofertilizers prior to planting (i.e., seed priming) reduces concerns about nanoparticle (NP) fertilizer non-target dispersion; however, priming formulations and concentrations must be carefully selected to avoid germination inhibition and toxicity. Here we investigate changes in corn seed germination and seedling development after seed priming with ZnO NPs, ZnO bulk and ZnCl₂. To evaluate the effects sterile seeds were immersed in priming solutions of 0, 20, 40, 80, 160 mg L⁻¹ Zn for the three Zn sources. Following an 8 h priming the seeds were …

Reformulated Red Mud: A Robust Catalyst For In Situ Catalytic Pyrolysis Of Biomass, Foster Agblevor, Huamin Wang, S. Beis, K. Christian, A. Slade, O. Hietsoi, D. M. Santosa

Biological Engineering Faculty Publications

Biomass feedstocks contain inorganic compounds generally classified as ash. The ash consists of compounds of potassium, calcium, magnesium, silicon, phosphorus. and other elements. These elements have been reported to influence both the pyrolysis reactions as well as the destabilization of the pyrolysis oils during storage. The inorganic elements have also been reported to deposit on catalyst surfaces during in situ catalytic pyrolysis leading to the eventual deactivation of acidic catalysts such as zeolites. The deposition of inorganic elements and their effects on formulated red mud (FRM) catalyst during in situ catalytic pyrolysis of pinyon juniper wood was investigated. The inorganic …

A Multi-Scale Approach To Study Biochemical And Biophysical Aspects Of Resveratrol On Diesel Exhaust Particle-Human Primary Lung Cell Interaction, Wei Zhang, Qifei Li, Mingjie Tang, Han Zhang, Xiaoping Sun, Sige Zou, Judy L. Jensen, Theodore G. Liou, Anhong Zhou

Biological Engineering Faculty Publications

Diesel exhaust particles (DEPs) are major air pollutants that lead to numerous human disorders, especially pulmonary diseases, partly through the induction of oxidative stress. Resveratrol is a polyphenol that ameliorates the production of reactive oxygen species (ROS) and delays aging-related processes. Herein we studied the cytoprotective effect of resveratrol on DEP-exposed human lung cells in a factorial experimental design. This work investigates biophysical features including cellular compositions and biomechanical properties, which were measured at the single-cell level using confocal Raman microspectroscopy (RM) and atomic force microscopy (AFM), respectively. Principal component analysis (PCA), hierarchical cluster analysis (HCA) and partial least square …

Monitoring Silane Sol-Gel Kinetics With In-Situ Optical Turbidity Scanning And Dynamic Light Scattering, Abul Bashar Mohammad Giasuddin, David W. Britt

Biological Engineering Faculty Publications

Organosilanes (e.g., R’-SiOR₃) provide hydrophobic functionality in thin-film coatings, porous gels, and particles. Compared with tetraalkoxysilanes (SiOR₄), organosilanes exhibit distinct reaction kinetics and assembly mechanisms arising from steric and electronic properties of the R’ group on the silicon atom. Here, the hydrolysis and condensation pathways of n-propyltrimethoxy silane (nPM) and a tri-fluorinated analog of nPM, 3,3,3-trifluoropropyl trimethoxy silane (3F), were investigated under aqueous conditions at pH 1.7, 2.0, 3.0, and 4.0. Prior to hydrolysis, 3F and nPM are insoluble in water and form a lens at the bottom (3F) or top (nPM) of the solutions. This …

Application Of Micro-Scale 3d Printing In Pharmaceutics, Andrew Kjar, Yu Huang

Biological Engineering Faculty Publications

3D printing, as one of the most rapidly-evolving fabrication technologies, has released a cascade of innovation in the last two decades. In the pharmaceutical field, the integration of 3D printing technology has offered unique advantages, especially at the micro-scale. When printed at a micro-scale, materials and devices can provide nuanced solutions to controlled release, minimally invasive delivery, high-precision targeting, biomimetic models for drug discovery and development, and future opportunities for personalized medicine. This review aims to cover the recent advances in this area. First, the 3D printing techniques are introduced with respect to the technical parameters and features that are …

Discovery And Engineering Of An Endophytic Pseudomonas Strain From Taxus Chinensis For Efficient Production Of Zeaxanthin Diglucoside, Ozkan Fidan, Jixun Zhan

Biological Engineering Faculty Publications

Background

Endophytic microorganisms are a rich source of bioactive natural products. They are considered as promising biofertilizers and biocontrol agents due to their growth-promoting interactions with the host plants and their bioactive secondary metabolites that can help manage plant pathogens. Identification of new endophytes may lead to the discovery of novel molecules or provide new strains for production of valuable compounds.

Results

In this study, we isolated an endophytic bacterium from the leaves of Taxus chinensis, which was identified as Pseudomonas sp. 102515 based on the 16S rRNA gene sequence and physiological characteristics. Analysis of its secondary metabolites revealed …

Microwave Assisted Sol-Gel Synthesis Of Silica-Spider Silk Composites, Abul Bashar Mohammad Giasuddin, David W. Britt

Biological Engineering Faculty Publications

This study introduces a simple and environmentally friendly method to synthesize silica-protein nanocomposite materials using microwave energy to solubilize hydrophobic protein in an aqueous solution of pre-hydrolyzed organo- or fluoro-silane. Sol-gel functionality can be enhanced through biomacromolecule incorporation to tune mechanical properties, surface energy, and biocompatibility. Here, synthetic spider silk protein and organo- and fluoro-silane precursors were dissolved and mixed in weakly acidic aqueous solution using microwave technology. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) images revealed the formation of spherical nanoparticles with sizes ranging from 100 to 500 nm depending, in part, on silane fluoro- or organo-side …

Improved Production Of Antifungal Angucycline Sch47554 By Manipulating Three Regulatory Genes In Streptomyces Sp. Scc-2136, Ozkan Fidan, Riming Yan, Du Zhu, Jixun Zhan

Biological Engineering Faculty Publications

Sch47554 and Sch47555 are two angucyclines with antifungal activities against various yeasts and dermatophytes from Streptomyces sp. SCC‐2136. The schgene cluster contains several putative regulatory genes. Both schA4 and schA21were predicted as the TetR family transcriptional regulators, whereas schA16shared significant similarity to the AraC family transcriptional regulators. Although Sch47554 is the major product of Streptomyces sp. SCC‐2136, its titer is only 6.72 mg/L. This work aimed to increase the production of this promising antifungal compound by investigating and manipulating the regulatory genes in the Sch47554 biosynthetic pathway. Disruption of schA4and schA16 led to a significant increase …

Use Of Surface-Enhanced Raman Scattering (Sers) Probes To Detect Fatty Acid Receptor Activity In A Microfluidic Device, Han Zhang, Wei Zhang, Lifu Xiao, Yan Liu, Timothy A. Gilbertson, Anhong Zhou

Biological Engineering Faculty Publications

In this study, 4-mercaptobenzoic acid (MBA)-Au nanorods conjugated with a GPR120 antibody were developed as a highly sensitive surface-enhanced Raman spectroscopy (SERS) probe, and were applied to detect the interaction of fatty acids (FA) and their cognate receptor, GPR120, on the surface of human embryonic kidney cells (HEK293-GPRR120) cultured in a polydimethylsiloxane (PDMS) microfluidic device. Importantly, the two dominant characteristic SERS peaks of the Raman reporter molecule MBA, 1078 cm⁻¹ and 1581 cm⁻¹, do not overlap with the main Raman peaks from the PDMS substrate when the appropriate spectral scanning range is selected, which effectively avoided the …

Develop A 3d Neurological Disease Model Of Human Cortical Glutamatergic Neurons Using Micropillar-Based Scaffolds, Cheng Chen, Xin Dong, Kai-Heng Fang, Fang Yuan, Yao Hu, Min Xu, Yu Huang, Xixiang Zhang, Danjun Fang, Yan Liu

Biological Engineering Faculty Publications

Establishing an effective three-dimensional (3D) in vitro culture system to better model human neurological diseases is desirable, since the human brain is a 3D structure. Here, we demonstrated the development of a polydimethylsiloxane (PDMS) pillar-based 3D scaffold that mimicked the 3D microenvironment of the brain. We utilized this scaffold for the growth of human cortical glutamatergic neurons that were differentiated from human pluripotent stem cells. In comparison with the 2D culture, we demonstrated that the developed 3D culture promoted the maturation of human cortical glutamatergic neurons by showing significantly more MAP2 and less Ki67 expression. Based on this 3D culture …

Identification Of New Glutamate Decarboxylases From Streptomyces For Efficient Production Of Γ-Aminobutyric Acid In Engineered Escherichia Coli, Haina Yuan, Hongbo Wang, Ozkan Fidan, Yong Qin, Gongnian Xiao, Jixun Zhan

Biological Engineering Faculty Publications

Background

Gamma (γ)-Aminobutyric acid (GABA) as a bioactive compound is used extensively in functional foods, pharmaceuticals and agro-industry. It can be biosynthesized via decarboxylation of monosodium glutamate (MSG) or L-glutamic acid (L-Glu) by glutamate decarboxylase (GAD; EC4.1.1.15). GADs have been identified from a variety of microbial sources, such as Escherichia coli and lactic acid bacteria. However, no GADs from Streptomyces have been characterized. The present study is aimed to identify new GADs from Streptomyces strains and establish an efficient bioproduction platform for GABA in E. coli using these enzymes.

Results

By sequencing and analyzing the genomes of three Streptomycesstrains, …

Muscle Atrophy Marker Expression Differs Between Rotary Cell Culture System And Animal Studies, Charles P. Harding, Elizabeth Vargis

Biological Engineering Faculty Publications

Muscular atrophy, defined as the loss of muscle tissue, is a serious issue for immobilized patients on Earth and for humans during spaceflight, where microgravity prevents normal muscle loading. In vitro modeling is an important step in understanding atrophy mechanisms and testing countermeasures before animal trials. The most ideal environment for modeling must be empirically determined to best mimic known responses in vivo. To simulate microgravity conditions, murine C2C12 myoblasts were cultured in a rotary cell culture system (RCCS). Alginate encapsulation was compared against polystyrene microcarrier beads as a substrate for culturing these adherent muscle cells. Changes after culture …

Identification And Heterologous Reconstitution Of A 5-Alk(En)Ylresorcinol Synthase From Endophytic Fungus Shiraia Sp. Slf14, Huiwen Yan, Lei Sun, Jinge Huang, Yixing Qiu, Fuchao Xu, Riming Yan, Du Zhu, Wei Wang, Jixun Zhan

Biological Engineering Faculty Publications

A new type III polyketide synthase gene (Ssars) was discovered from the genome of Shiraia sp. Slf14, an endophytic fungal strain from Huperzia serrata. The intron-free gene was cloned from the cDNA and ligated to two expression vectors pET28a and YEpADH2p-URA3 for expression in Escherichia coli BL21(DE3) and Saccharomyces cerevisiae BJ5464, respectively. SsARS was efficiently expressed in E. coli BL21(DE3), leading to the synthesis of a series of polyketide products. Six major products were isolated from the engineered E. coli and characterized as 1,3-dihydroxyphenyl-5-undecane, 1,3-dihydroxyphenyl-5-cis-6'-tridecene,1,3-dihydroxyphenyl-5-tridecane, 1,3-dihydroxyphenyl-5-cis-8'-pentadecene, 1,3-dihydroxyphenyl-5-pentadecane and 1,3-dihydroxyphenyl-5-cis-10'-heptadecene, respectively, …

Novel Devices For Studying Acute And Chronic Mechanical Stress In Retinal Pigment Epithelial Cells, Farhad Farjood, Elizabeth Vargis

Biological Engineering Faculty Publications

Choroidal neovascularization (CNV) is a major cause of blindness in patients with age-related macular degeneration (AMD). Overexpression of vascular endothelial growth factor (VEGF), a potent angiogenic protein, by retinal pigment epithelial (RPE) cells is a key stimulator of CNV. Mechanical stress occurs during different stages of AMD and is a possible inducer of VEGF expression in RPE cells. However, robust and realistic approaches to studying acute and chronic mechanical stress under various AMD stages do not exist.The majority of previous work has studied cyclic stretching of RPE cells grown on flexible substrates, but an ideal model must be able to …

Hydrodeoxygenation Of Aqueous Phase Catalytic Pyrolysis Oil To Liquid Hydrocarbons Using Multi-Functional Nickel Catalyst, Hossein Jahromi, Foster A. Agblevor

Biological Engineering Faculty Publications

Herein we investigated the hydrodeoxygenation (HDO) of aqueous phase pinyon-juniper catalytic pyrolysis oil (APPJCPO) using a new multifunctional red mud-supported nickel (Ni/RM) catalyst. The organic liquid yield after HDO of APPJCPO using 30 wt. % Ni/RM at reaction temperature of 350 °C was 47.8 wt. % with oxygen content of 1.14 wt. %. The organic liquid fraction consisted of aliphatics, aromatics, and alkylated aromatic hydrocarbons as well as small amounts of oxygenates. The RM support catalyzed ketonization of carboxylic acids. The Ni metal catalyzed partial reduction of oxygenates that underwent carbonyl alkylation with aldehydes and ketones on the RM. Catalyst …

An Efficient Process For Co-Production Of Γ-Aminobutyric Acid And Probiotic Bacillus Subtilis Cells, Hongbo Wang, Jinge Huang, Lei Sun, Fuchao Xu, Wei Zhang, Jixun Zhan

Biological Engineering Faculty Publications

This study was to establish an integrated process for the co-production of γ-aminobutyric acid (GABA) and live probiotics. Six probiotic bacteria were screened and Bacillus subtilis ATCC 6051 showed the highest GABA-producing capacity. The optimal temperature and initial pH value for GABA production in B. subtilis were found to be 30 °C and 8.0, respectively. A variety of carbon and nitrogen sources were tested, and potato starch and peptone were the preferred carbon and nitrogen sources for GABA production, respectively. The concentrations of carbon source, nitrogen source and substrate (sodium L-glutamate) were then optimized using the response surface methodology. The …

Method For The Destruction Of Endotoxin In Synthetic Spider Silk Proteins, Richard E. Decker, Thomas I. Harris, Dylan R. Memmott, Christopher J. Peterson, Randolph V. Lewis, Justin A. Jones

Biological Engineering Faculty Publications

Although synthetic spider silk has impressive potential as a biomaterial, endotoxin contamination of the spider silk proteins is a concern, regardless of the production method. The purpose of this research was to establish a standardized method to either remove or destroy the endotoxins present in synthetic spider silk proteins, such that the endotoxin level was consistently equal to or less than 0.25 EU/mL, the FDA limit for similar implant materials. Although dry heat is generally the preferred method for endotoxin destruction, heating the silk proteins to the necessary temperatures led to compromised mechanical properties in the resultant materials. In light …

Whole Cell Cross-Linking To Discover Host-Microbe Protein Cognate Receptor/Ligand Pairs, Bart C. Weimer, Poyin Chen, Prerak T. Desai, Dong Chen, Jigna Shah

Biological Engineering Faculty Publications

Bacterial surface ligands mediate interactions with the host cell during association that determines the specific outcome for the host–microbe association. The association begins with receptors on the host cell binding ligands on the microbial cell to form a partnership that initiates responses in both cells. Methods to determine the specific cognate partnerships are lacking. Determining these molecular interactions between the host and microbial surfaces are difficult, yet crucial in defining biologically important events that are triggered during association of the microbiome, and critical in defining the initiating signal from the host membrane that results in pathology or commensal association. In …

New Insights Into The Glycosylation Steps In The Biosynthesis Of Sch47554 And Sch47555, Ozkan Fidan, Riming Yan, Gabrielle Gladstone, Tong Zhou, Du Zhu, Jixun Zhan

Biological Engineering Faculty Publications

Sch47554 and Sch47555 are antifungal compounds from Streptomyces sp. SCC‐2136. The availability of the biosynthetic gene cluster made it possible to track genes that encode biosynthetic enzymes responsible for the structural features of these two angucyclines. Sugar moieties play important roles in the biological activities of many natural products. An investigation into glycosyltransferases (GTs) might potentially help to diversify pharmaceutically significant drugs through combinatorial biosynthesis. Sequence analysis indicates that SchS7 is a putative C‐GT, whereas SchS9 and SchS10 are proposed to be O‐GTs. In this study, the roles of these three GTs in the biosynthesis of Sch47554 and Sch47555 are …