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Full-Text Articles in Biotechnology

Effect Of Sugars On Artemisinin Production In Artemisia Annua L.: Transcription And Metabolite Measurements, Patrick Arsenault, Daniel Vail, Kristin Wobbe, Pamela Weathers Dec 2015

Effect Of Sugars On Artemisinin Production In Artemisia Annua L.: Transcription And Metabolite Measurements, Patrick Arsenault, Daniel Vail, Kristin Wobbe, Pamela Weathers

Kristin K. Wobbe

The biosynthesis of the valuable sesquiterpene anti-malarial, artemisinin, is known to respond to exogenous sugar concentrations. Here young Artemisia annua L. seedlings (strain YU) were used to measure the transcripts of six key genes in artemisinin biosynthesis in response to growth on sucrose, glucose, or fructose. The measured genes are: from the cytosolic arm of terpene biosynthesis, 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGR), farnesyl disphosphate (FPS); from the plastid arm of terpene biosynthesis, 1-deoxyxylulose-5-phosphate synthase (DXS), 1-deoxyxylulouse 5-phosphate reductoisomerase (DXR); from the dedicated artemisinin pathway amorpha-4,11-diene synthase (ADS), and the P450, CYP71AV1 (CYP). Changes in intracellular concentrations of artemisinin (AN) and its precursors, …


Dorsoventral Boundary For Organizing Growth And Planar Polarity In The Drosophila Eye, Amit Singh, Janghoo Lim, Kwang-Wook Choi Jul 2015

Dorsoventral Boundary For Organizing Growth And Planar Polarity In The Drosophila Eye, Amit Singh, Janghoo Lim, Kwang-Wook Choi

Amit Singh

A fundamental feature of developing tissues and organs is generation of planar polarity of cells in an epithelium with respect to the body axis.

The Drosophila compound eye shows two-tier dorsoventral (DV) planar polarity. At the individual ommatidium level, the eight photoreceptors in each unit eye form a dorsoventrally asymmetric cluster. At the level of eye field, hundreds of ommatidia in the upper and lower halves of an eye are uniformly polarized dorsally or ventrally, respectively. This results in DV mirror symmetries about the equator. The uniform orientations of photoreceptor clusters over long distance in the eye field provide an …


Prevalence And Effects Of Mycotoxins On Poultry Health And Performance, And Recent Development In Mycotoxin Counteracting Strategies, G. R. Murugesan, D Ledoux, K Naehrer, F Berthiller, T Applegate, B Grenier, T Phillips, G Schatzmayr Dec 2014

Prevalence And Effects Of Mycotoxins On Poultry Health And Performance, And Recent Development In Mycotoxin Counteracting Strategies, G. R. Murugesan, D Ledoux, K Naehrer, F Berthiller, T Applegate, B Grenier, T Phillips, G Schatzmayr

G. R. Murugesan

Extensive research over the last couple of decades has made it obvious that mycotoxins are commonly prevalent in majority of feed ingredients. A worldwide mycotoxin survey in 2013 revealed 81 % of around 3,000 grain and feed samples analyzed had at least one mycotoxin which was higher than the ten-year average (from 2004 to 2013) of 76% in a total of 25,944 samples. The considerable increase in the number of positive samples in 2013 may be due to the improvements in detection methods and their sensitivity. The recently developed liquid chromatography coupled to (tandem) mass spectrometry allows the inclusion of …


Individual Characteristics And Their Effect On Predicting Mu Rhythm Modulation, Adriane Randolph, Melody Jackson, Saurav Karmakar Aug 2014

Individual Characteristics And Their Effect On Predicting Mu Rhythm Modulation, Adriane Randolph, Melody Jackson, Saurav Karmakar

Adriane B. Randolph

Brain-computer interfaces (BCIs) offer users with severe motor disabilities a nonmuscular input channel for communication and control but require that users achieve a level of literacy and be able to harness their appropriate electrophysiological responses for effective use of the interface. There is currently no formalized process for determining a user's aptitude for control of various BCIs without testing on an actual system. This study presents how basic information captured about users may be used to predict modulation of mu rhythms, electrical variations in the motor cortex region of the brain that may be used for control of a BCI. …


Characterization Of A Recently Purified Thermophilic Dnase From A Novel Thermophilic Fungus, Kyle Landry, Robert Levin Jul 2014

Characterization Of A Recently Purified Thermophilic Dnase From A Novel Thermophilic Fungus, Kyle Landry, Robert Levin

Kyle S Landry

A newly isolated thermophilic fungus was found to produce a partially inducible extracellular DNase. This manuscript focuses on the characterization of this novel thermophilic DNase in terms of optimal enzyme conditions, molecular weight, and certain kinetic properties. The DNase was found to be inactivated by the presence of EDTA demonstrating its dependence on metal cofactors for activity. Maximum activity occurred at pH 6.0 with no activity at pH 2.0 or 10.0. The optimal temperature for the purified DNase was 65 °C. The thermophilic DNase was found to be an exonuclease with an estimated molecular weight of 56 kDa.


A Magnetic Compass Aids Monarch Butterfly Migration, Robert Gegear, Patrick Guerra, Steven Reppert Jun 2014

A Magnetic Compass Aids Monarch Butterfly Migration, Robert Gegear, Patrick Guerra, Steven Reppert

Robert J. Gegear

Convincing evidence that migrant monarch butterflies (Danaus plexippus) use a magnetic compass to aid their fall migration has been lacking from the spectacular navigational capabilities of this species. Here we use flight simulator studies to show that migrants indeed possess an inclination magnetic compass to help direct their flight equatorward in the fall. The use of this inclination compass is light-dependent utilizing ultraviolet-A/blue light between 380 and 420 nm. Notably, the significance of light <420 nm for inclination compass function was not considered in previous monarch studies. The antennae are important for the inclination compass because they appear to contain light-sensitive magnetosensors. For migratory monarchs, the inclination compass may serve as an important orientation mechanism when directional daylight cues are unavailable and may also augment time-compensated sun compass orientation for appropriate directionality throughout the migration.


Hits-Clip And Integrative Modeling Define The Rbfox Splicing-Regulatory Network Linked To Brain Development And Autism, Natalie Farny, Sebastien Weyn-Vanhentenryck, Aldo Mele, Qinghong Yan, Shuying Sun, Zuo Zhang, Chenghai Xue, Margaret Herre, Pamela Silver, Michael Zhang, Adrian Krainer, Robert Darnell, Chaolin Zhang Mar 2014

Hits-Clip And Integrative Modeling Define The Rbfox Splicing-Regulatory Network Linked To Brain Development And Autism, Natalie Farny, Sebastien Weyn-Vanhentenryck, Aldo Mele, Qinghong Yan, Shuying Sun, Zuo Zhang, Chenghai Xue, Margaret Herre, Pamela Silver, Michael Zhang, Adrian Krainer, Robert Darnell, Chaolin Zhang

Natalie G. Farny

The RNA binding proteins Rbfox1/2/3 regulate alternative splicing in the nervous system, and disruption of Rbfox1 has been implicated in autism. However, comprehensive identification of functional Rbfox targets has been challenging. Here, we perform HITS-CLIP for all three Rbfox family members in order to globally map, at a single-nucleotide resolution, their in vivo RNA interaction sites in the mouse brain. We find that the two guanines in the Rbfox binding motif UGCAUG are critical for protein-RNA interactions and crosslinking. Using integrative modeling, these interaction sites, combined with additional datasets, define 1,059 direct Rbfox target alternative splicing events. Over half of …


Development Of A Novel Affinity Membrane Purification System For Deoxyribonuclease, Kyle Landry, Robert Levin Jan 2014

Development Of A Novel Affinity Membrane Purification System For Deoxyribonuclease, Kyle Landry, Robert Levin

Kyle S Landry

A membrane based affinity purification system was developed for the purification of the DNA specific nuclease, DNase I. Single stranded DNA was bound to unmodified polyvinylidene fluoride (PVDF) membranes which were used to purify DNase I from a solution of bovine serum albumin. Using coated membranes, a 6-fold increase in specific activity was achieved with 80 % enzyme recovery. This method provides a simple yet effective way to purify DNase I and can be very useful for the purification of other DNA specific enzymes.


Purification Of An Inducible Dnase From A Thermophilic Fungus, Kyle Landry, Andrea Vu, Robert Levin Dec 2013

Purification Of An Inducible Dnase From A Thermophilic Fungus, Kyle Landry, Andrea Vu, Robert Levin

Kyle S Landry

The ability to induce an extracellular DNase from a novel thermophilic fungus was studied and the DNAse purified using both traditional and innovative purification techniques. The isolate produced sterile hyphae under all attempted growing conditions, with an average diameter of 2 μm and was found to have an optimal temperature of 45 °C and a maximum of 65 °C. Sequencing of the internal transcribed region resulted in a 91% match with Chaetomium sp., suggesting a new species, but further clarification on this point is needed. The optimal temperature for DNase production was found to be 55 °C and was induced by the …


Purification And Characterization Of Iso-Ribonucleases From A Novel Thermophilic Fungus, Kyle Landry, Robert Levin Dec 2013

Purification And Characterization Of Iso-Ribonucleases From A Novel Thermophilic Fungus, Kyle Landry, Robert Levin

Kyle S Landry

A thermophilic fungus previously isolated from composted horse manure was found to produce extracellular iso-RNases that were purified 127.6-fold using a combination of size exclusion chromatography and a novel affinity membrane purification system. The extent of purification was determined electrophoretically using 4%–15% gradient polyacrylamide gels. RNase activity was dependent on the presence of a metal co-factor with significantly more activity with Zn2+ or Mn2+ than Mg2+. The RNases exhibited maximum activity at both pH 3.0 and pH 7.0 with no activity at pH 2.0 or 10.0. The optimal temperature for the iso-RNase was 70 °C. The …


High-Throughput Imaging Of Neuronal Activity In Caenorhabditis Elegans, Dirk Albrecht, Johannes Larsch, Donovan Ventimiglia, Cornelia Bargmann Oct 2013

High-Throughput Imaging Of Neuronal Activity In Caenorhabditis Elegans, Dirk Albrecht, Johannes Larsch, Donovan Ventimiglia, Cornelia Bargmann

Dirk R. Albrecht

Neuronal responses to sensory inputs can vary based on genotype, development, experience, or stochastic factors. Existing neuronal recording techniques examine a single animal at a time, limiting understanding of the variability and range of potential responses. To scale up neuronal recordings, we here describe a system for simultaneous wide-field imaging of neuronal calcium activity from at least 20 Caenorhabditis elegans animals under precise microfluidic chemical stimulation. This increased experimental throughput was used to perform a systematic characterization of chemosensory neuron responses to multiple odors, odor concentrations, and temporal patterns, as well as responses to pharmacological manipulation. The system allowed recordings …


Acute Toxicity Of Copper Sulfate And Potassium Dichromate On Stygobiont Proasellus: General Aspects Of Groundwater Ecotoxicology And Future Perspectives, Ana Reboleira, Nelson Abrantes, Pedro Oromí, Fernando Gonçalves Mar 2013

Acute Toxicity Of Copper Sulfate And Potassium Dichromate On Stygobiont Proasellus: General Aspects Of Groundwater Ecotoxicology And Future Perspectives, Ana Reboleira, Nelson Abrantes, Pedro Oromí, Fernando Gonçalves

Ana Sofia P.S. Reboleira

Karst systems harbor large groundwater resources for human consumption and represent an important habitat for rare and unprotected specialized animals, the so-called stygofauna. Due to the highly adapted features towards underground life, together with the geographic isolation provided by the subterranean aquifers, groundwater-dwelling animals may lose the ability to face sudden changes on their ecosystems, and therefore the risk of extinction is remarkably high. A little is known about their sensitiveness, especially linked to contamination pressure in urbanized karst areas. Understanding the impact of contaminants on stygofauna is important for setting groundwater environmental quality and management of karst systems. We …


Nietzsche’S Post-Human Imperative: On The “All-Too-Human” Dream Of Transhumanism, Babette Babich Nov 2012

Nietzsche’S Post-Human Imperative: On The “All-Too-Human” Dream Of Transhumanism, Babette Babich

Babette Babich

No abstract provided.


Eight Is Enough?: The Ethics Of The California Octuplets Case, Scott Paeth Oct 2012

Eight Is Enough?: The Ethics Of The California Octuplets Case, Scott Paeth

Scott R. Paeth

The recent California octuplets case raises a number of important issues that need to be addressed in the context of the increasingly widespread practice of in vitro fertilization. This paper explores some of those issues as looked at from the perspective of protestant theological ethics and public theology, examining the moral responsibilities of the various participants in the process, both before and after the octuplets’ birth, including the mother, her doctors, the health care bureaucracy, the wider society, and the media. Each of these participants failed in significant respects to consider the ethical implications of the births in this complicated …


Purification And Characterization Of Novel Nucleases From A Thermophilic Fungus, Kyle Landry Sep 2012

Purification And Characterization Of Novel Nucleases From A Thermophilic Fungus, Kyle Landry

Kyle S Landry

A thermophilic fungus was isolated from composted horse manure. The organism was as a Chaetomium sp. by sequencing the highly conserved ITS region of the fungus and comparing to known regions in a genomic database and was referred to as TM-417. TM-417 was found to have an optimal growth temperature of 45 oC and an optimal pH of 7.0. An extracellular DNase and RNase was found to be produced by the isolate and were purified 145.58-fold and 127.6-fold respectively using a combination of size exclusion chromatography and a novel affinity membrane purification system. The extent of purification was determined …


Discordant Timing Between Antennae Disrupts Sun Compass Orientation In Migratory Monarch Butterflies, Robert Gegear, Patrick Guerra, Christine Merlin, Steven Reppert Jul 2012

Discordant Timing Between Antennae Disrupts Sun Compass Orientation In Migratory Monarch Butterflies, Robert Gegear, Patrick Guerra, Christine Merlin, Steven Reppert

Robert J. Gegear

To navigate during their long-distance migration, monarch butterflies (Danaus plexippus) use a time-compensated sun compass. The sun compass timing elements reside in light-entrained circadian clocks in the antennae. Here we show that either antenna is sufficient for proper time compensation. However, migrants with either antenna painted black (to block light entrainment) and the other painted clear (to permit light entrainment) display disoriented group flight. Remarkably, when the black-painted antenna is removed, re-flown migrants with a single, clear-painted antenna exhibit proper orientation behaviour. Molecular correlates of clock function reveal that period and timeless expression is highly rhythmic in brains and clear-painted …


Star Rna-Binding Protein Quaking Suppresses Cancer Via Stabilization Of Specific Mirna, Natalie Farny, An-Jou Chen, Ji-Hye Paik, Hailei Zhang, Sachet Shukla, Richard Mortensen, Jian Hu, Haoqiang Ying, Baoli Hu, Jessica Hurt, Caroline Dong, Yonghong Xiao, Y. Wang, Pamela Silver, Lynda Chin, Shobha Vasudevan, Ronald Depinho Jun 2012

Star Rna-Binding Protein Quaking Suppresses Cancer Via Stabilization Of Specific Mirna, Natalie Farny, An-Jou Chen, Ji-Hye Paik, Hailei Zhang, Sachet Shukla, Richard Mortensen, Jian Hu, Haoqiang Ying, Baoli Hu, Jessica Hurt, Caroline Dong, Yonghong Xiao, Y. Wang, Pamela Silver, Lynda Chin, Shobha Vasudevan, Ronald Depinho

Natalie G. Farny

Multidimensional cancer genome analysis and validation has defined Quaking (QKI), a member of the signal transduction and activation of RNA (STAR) family of RNA-binding proteins, as a novel glioblastoma multiforme (GBM) tumor suppressor. Here, we establish that p53 directly regulates QKI gene expression, and QKI protein associates with and leads to the stabilization of miR-20a; miR-20a, in turn, regulates TGFβR2 and the TGFβ signaling network. This pathway circuitry is substantiated by in silico epistasis analysis of its components in the human GBM TCGA (The Cancer Genome Atlas Project) collection and by their gain- and loss-of-function interactions in in vitro and …


Proteomic Analysis Of 17Β-Estradiol Degradation By Stenotrophomonas Maltophilia, Zhongtian Li May 2012

Proteomic Analysis Of 17Β-Estradiol Degradation By Stenotrophomonas Maltophilia, Zhongtian Li

Z Li

Microbial degradation plays a critical role in determining the environmental fate of steroid hormones, such as 17β-estradiol (E2). The molecular mechanisms governing the microbial transformation of E2 and its primary degradation intermediate, estrone (E1), are largely unknown. The objective of this study was to identify metabolism pathways that might be involved in microbial estrogen degradation. To achieve the objective, Stenotrophomonas maltophilia strain ZL1 was used as a model estrogen degrading bacterium and its protein expression level during E2/E1 degradation was studied using quantitative proteomics. During an E2 degradation experiment, strain ZL1 first converted E2 to E1 stoichiometrically. At 16 h …


Removing 17Β-Estradiol From Drinking Water In A Biologically Active Carbon (Bac) Reactor Modified From A Granular Activated Carbon (Gac) Reactor, Zhongtian Li Mar 2012

Removing 17Β-Estradiol From Drinking Water In A Biologically Active Carbon (Bac) Reactor Modified From A Granular Activated Carbon (Gac) Reactor, Zhongtian Li

Z Li

Estrogenic compounds in drinking water sources pose potential threats to human health. Treatment technologies are needed to effectively remove these compounds for the production of safe drinking water. In this study, GAC adsorption was first tested for its ability to remove a model estrogenic compound, 17β-estradiol (E2). Although GAC showed a relatively high adsorption capacity for E2 in isotherm experiments, it appeared to have a long mass transfer zone in a GAC column reactor, causing an early leakage of E2 in the effluent. With an influent E2 concentration of 20 μg/L, the GAC reactor was able to bring down effluent …


Viability Of Lactic Acid Bacteria And Sensory Evaluation In Cinnamomum Verum And Allium Sativum-Bio-Yogurts Made From Camel And Cow Milk, Ahmad Salihin Hj Baba, Shori A. B. Dec 2011

Viability Of Lactic Acid Bacteria And Sensory Evaluation In Cinnamomum Verum And Allium Sativum-Bio-Yogurts Made From Camel And Cow Milk, Ahmad Salihin Hj Baba, Shori A. B.

Ahmad Salihin Hj Baba

The present study investigate the effect of herbal water extract prepared from Allium sativum and Cinnamomum verum on the viability of lactic acid bacteria (Lactobacillus spp and Streptococcus thermophilus) in cow- and camel-milk yogurts during 21 day refrigerated storage. The organoleptic properties of fresh-yogurts were evaluated. Lactobacillus spp count for fresh cow milk-yogurts (0 day) in both present and absent of C. verum and A. sativum was ranged from 1.4×0 6 to 2.1×10 6 cfu/mL. These values were not significantly changed throughout the 21 days of refrigerated storage. Lactobacillusspp count in fresh plain camel milk- yogurt was 13.2×10 6 cfu/mL …


Human Cryptochrome Exhibits Light-Dependent Magnetosensitivity, Robert Gegear, Lauren Foley, Steven Reppert May 2011

Human Cryptochrome Exhibits Light-Dependent Magnetosensitivity, Robert Gegear, Lauren Foley, Steven Reppert

Robert J. Gegear

Humans are not believed to have a magnetic sense, even though many animals use the Earth's magnetic field for orientation and navigation. One model of magnetosensing in animals proposes that geomagnetic fields are perceived by light-sensitive chemical reactions involving the flavoprotein cryptochrome (CRY). Here we show using a transgenic approach that human CRY2, which is heavily expressed in the retina, can function as a magnetosensor in the magnetoreception system of Drosophila and that it does so in a light-dependent manner. The results show that human CRY2 has the molecular capability to function as a light-sensitive magnetosensor and reopen an area …


Development Of A Simple Model Device For In Vitro Gastric Digestion Investigation, Vish Gaikwad Feb 2011

Development Of A Simple Model Device For In Vitro Gastric Digestion Investigation, Vish Gaikwad

Vish Shashank Gaikwad

No abstract provided.


Water Deficit-Induced Changes On Growth Parameters And Radiation Use Efficiency Of Promising Durum Wheat Genotypes, Amru Nasrulhaq Boyce Dec 2010

Water Deficit-Induced Changes On Growth Parameters And Radiation Use Efficiency Of Promising Durum Wheat Genotypes, Amru Nasrulhaq Boyce

Amru Bin Nasrulhaq Boyce

The present study was carried out to study the performance of durum and bread wheat genotypes in relation to accumulation of dry matter, growth parameters, photosynthetically active radiation interception and radiation use efficiency under different irrigation regimes. The experiment was laid out in a split plot based on a complete randomized block design. Irrigation regime was considered as the main plots and included four levels. Sub-plots were assigned to four durum-promising lines and a bread wheat cultivar. It was observed that water limitation significantly decreased the accumulation of dry matter, growth parameter values, photosynthetically active radiation interception and radiation use …


Metazoan Stress Granule Assembly Is Mediated By P-Eif2alpha-Dependent And -Independent Mechanisms, Natalie Farny, Nancy Kedersha, Pamela Silver Sep 2009

Metazoan Stress Granule Assembly Is Mediated By P-Eif2alpha-Dependent And -Independent Mechanisms, Natalie Farny, Nancy Kedersha, Pamela Silver

Natalie G. Farny

Stress granules (SGs) are cytoplasmic bodies wherein translationally silenced mRNAs are recruited for triage in response to environmental stress. We report that Drosophila cells form SGs in response to arsenite and heat shock. Drosophila SGs, like mammalian SGs, are distinct from but adjacent to processing bodies (PBs, sites of mRNA silencing and decay), require polysome disassembly, and are in dynamic equilibrium with polysomes. We further examine the role of the two Drosophila eIF2alpha kinases, PEK and GCN2, in regulating SG formation in response to heat and arsenite stress. While arsenite-induced SGs are dependent upon eIF2alpha phosphorylation, primarily via PEK, heat-induced …


Stranger In A Strange Land: Biotechnology And The Federal Circuit, Lawrence Sung Sep 2009

Stranger In A Strange Land: Biotechnology And The Federal Circuit, Lawrence Sung

Lawrence M. Sung

No abstract provided.


A Conserved Ccch-Type Zinc Finger Protein Regulates Mrna Nuclear Adenylation And Export, Natalie Farny, Jessica Hurt, Robert Obar, Steven Gygi, Pamela Silver, Bo Zhai Apr 2009

A Conserved Ccch-Type Zinc Finger Protein Regulates Mrna Nuclear Adenylation And Export, Natalie Farny, Jessica Hurt, Robert Obar, Steven Gygi, Pamela Silver, Bo Zhai

Natalie G. Farny

Coupling of messenger RNA (mRNA) nuclear export with prior processing steps aids in the fidelity and efficiency of mRNA transport to the cytoplasm. In this study, we show that the processes of export and polyadenylation are coupled via the Drosophila melanogaster CCCH-type zinc finger protein CG6694/dZC3H3 through both physical and functional interactions. We show that depletion of dZC3H3 from S2R+ cells results in transcript hyperadenylation. Using targeted coimmunoprecipitation and liquid chromatography mass spectrometry (MS)/MS techniques, we characterize interactions of known components of the mRNA nuclear export and polyadenylation machineries with dZC3H3. Furthermore, we demonstrate the functional conservation of this factor, …


Defining Behavioral And Molecular Differences Between Summer And Migratory Monarch Butterflies, Robert Gegear, Haisun Zhu, Amy Casselman, Sriramana Kanginakudru, Steven Reppert Mar 2009

Defining Behavioral And Molecular Differences Between Summer And Migratory Monarch Butterflies, Robert Gegear, Haisun Zhu, Amy Casselman, Sriramana Kanginakudru, Steven Reppert

Robert J. Gegear

Background: In the fall, Eastern North American monarch butterflies (Danaus plexippus) undergo a magnificent long-range migration. In contrast to spring and summer butterflies, fall migrants are juvenile hormone deficient, which leads to reproductive arrest and increased longevity. Migrants also use a time-compensated sun compass to help them navigate in the south/southwesterly direction en route for Mexico. Central issues in this area are defining the relationship between juvenile hormone status and oriented flight, critical features that differentiate summer monarchs from fall migrants, and identifying molecular correlates of behavioral state. Results: Here we show that increasing juvenile hormone activity to induce summer-like …


Definition Of Global And Transcript-Specific Mrna Export Pathways In Metazoans, Natalie Farny, Jessica Hurt, Pamela Silver Dec 2007

Definition Of Global And Transcript-Specific Mrna Export Pathways In Metazoans, Natalie Farny, Jessica Hurt, Pamela Silver

Natalie G. Farny

Eukaryotic gene expression requires export of messenger RNAs (mRNAs) from their site of transcription in the nucleus to the cytoplasm where they are translated. While mRNA export has been studied in yeast, the complexity of gene structure and cellular function in metazoan cells has likely led to increased diversification of these organisms' export pathways. Here we report the results of a genome-wide RNAi screen in which we identify 72 factors required for polyadenylated [poly-(A(+))] mRNA export from the nucleus in Drosophila cells. Using structural and functional conservation analysis of yeast and Drosophila mRNA export factors, we expose the evolutionary divergence …


Multiphase Electropatterning Of Cells And Biomaterials, Dirk Albrecht, Gregory Underhill, Avital Mendelson§, Sangeeta Bhatia May 2007

Multiphase Electropatterning Of Cells And Biomaterials, Dirk Albrecht, Gregory Underhill, Avital Mendelson§, Sangeeta Bhatia

Dirk R. Albrecht

Tissues formed by cells encapsulated in hydrogels have uses in biotechnology, cell-based assays, and tissue engineering. We have previously presented a 3D micropatterning technique that rapidly localizes live cells within hydrogels using dielectrophoretic (DEP) forces, and have demonstrated the ability to modulate tissue function through the control of microscale cell architecture. A limitation of this method is the requirement that a single biomaterial must simultaneously harbor biological properties that support cell survival and function and material properties that permit efficient dielectrophoretic patterning. Here, we resolve this issue by forming multiphase tissues consisting of microscale tissue sub-units in a ‘local phase’ …


Photo- And Electropatterning Of Hydrogel-Encapsulated Living Cell Arrays, Dirk Albrecht, Valerie Tsang, Robert Sah, Sangeeta Bhatia Nov 2004

Photo- And Electropatterning Of Hydrogel-Encapsulated Living Cell Arrays, Dirk Albrecht, Valerie Tsang, Robert Sah, Sangeeta Bhatia

Dirk R. Albrecht

Living cells have the potential to serve as sensors, naturally integrating the response to stimuli to generate predictions about cell fate (e.g., differentiation, migration, proliferation, apoptosis). Miniaturized arrays of living cells further offer the capability to interrogate many cells in parallel and thereby enable high-throughput and/or combinatorial assays. However, the interface between living cells and synthetic chip platforms is a critical one wherein the cellular phenotype must be preserved to generate useful signals. While some cell types retain tissue-specific features on a flat (2-D) surface, it has become increasingly apparent that a 3-D physical environment will be required for others. …