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Full-Text Articles in Cell Biology

Mir-14 Regulates Autophagy During Developmental Cell Death By Targeting Ip3-Kinase 2, Charles Nelson, Victor Ambros, Eric Baehrecke Oct 2015

Mir-14 Regulates Autophagy During Developmental Cell Death By Targeting Ip3-Kinase 2, Charles Nelson, Victor Ambros, Eric Baehrecke

Victor R. Ambros

Macroautophagy (autophagy) is a lysosome-dependent degradation process that has been implicated in age-associated diseases. Autophagy is involved in both cell survival and cell death, but little is known about the mechanisms that distinguish its use during these distinct cell fates. Here, we identify the microRNA miR-14 as being both necessary and sufficient for autophagy during developmentally regulated cell death in Drosophila. Loss of miR-14 prevented induction of autophagy during salivary gland cell death, but had no effect on starvation-induced autophagy in the fat body. Moreover, misexpression of miR-14 was sufficient to prematurely induce autophagy in salivary glands, but not in ...


Three-Dimensional Confocal Microscopy Indentation Method For Hydrogel Elasticity Measurement, Donghee Lee, Md Mahmudur Rahman, You Zhou, Sangjin Ryu Aug 2015

Three-Dimensional Confocal Microscopy Indentation Method For Hydrogel Elasticity Measurement, Donghee Lee, Md Mahmudur Rahman, You Zhou, Sangjin Ryu

Md Mahmudur Rahman

No abstract provided.


Differential Muscle Hypertrophy Is Associated With Satellite Cell Numbers And Akt Pathway Activation Following Activin Type Iib Receptor Inhibition In Mtm1 P.R69c Mice, Michael Lawlor, Marissa Viola, Hui Meng, Rachel Edelstein, Fujun Liu, Ke Yan, Elizabeth Luna, Alexandra Lerch-Gaggl, Raymond Hoffmann, Christopher Pierson, Anna Buj-Bello, Jennifer Lachey, Scott Pearsall, Lin Yang, Cecilia Hillard, Alan Beggs Oct 2014

Differential Muscle Hypertrophy Is Associated With Satellite Cell Numbers And Akt Pathway Activation Following Activin Type Iib Receptor Inhibition In Mtm1 P.R69c Mice, Michael Lawlor, Marissa Viola, Hui Meng, Rachel Edelstein, Fujun Liu, Ke Yan, Elizabeth Luna, Alexandra Lerch-Gaggl, Raymond Hoffmann, Christopher Pierson, Anna Buj-Bello, Jennifer Lachey, Scott Pearsall, Lin Yang, Cecilia Hillard, Alan Beggs

Elizabeth J. Luna

X-linked myotubular myopathy is a congenital myopathy caused by deficiency of myotubularin. Patients often present with severe perinatal weakness, requiring mechanical ventilation to prevent death from respiratory failure. We recently reported that an activin receptor type IIB inhibitor produced hypertrophy of type 2b myofibers and modest increases of strength and life span in the severely myopathic Mtm1δ4 mouse model of X-linked myotubular myopathy. We have now performed a similar study in the less severely symptomatic Mtm1 p.R69C mouse in hopes of finding greater treatment efficacy. Activin receptor type IIB inhibitor treatment of Mtm1 p.R69C animals produced behavioral and ...


Chronic Induction Of Breast Cell Carcinogenesis By Multiple Environmental And Dietary Carcinogens, Lenora Pluchino, Hwa-Chain Robert Wang Apr 2014

Chronic Induction Of Breast Cell Carcinogenesis By Multiple Environmental And Dietary Carcinogens, Lenora Pluchino, Hwa-Chain Robert Wang

Lenora A. Pluchino, Ph.D.

Breast cancer, the most common type of cancer among North American and European women, is mostly sporadic and attributable to long-term exposure to small quantities of multiple carcinogens. To understand how multiple carcinogens act together to induce breast cell carcinogenesis, we investigated the activity of the tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), the environmental carcinogen benzo[a]pyrene (B[a]P), and the dietary carcinogen 2-amino-1-methyl-6- phenylimidazo[4,5-b]pyridine (PhIP). Non-cancerous human breast epithelial MCF10A cells were exposed to NNK, B[a]P, and PhIP sequentially or in combination and then analyzed for the acquisition of cancerous ...


Guanosine Diphosphatase Is Required For Protein And Sphingolipid Glycosylation In The Golgi Lumen Of Saccharomyces Cerevisiae, Claudia Abeijon, Ken Yanagisawa, Elisabet Mandon, Alex Hausler, Kelley Moremen, Carlos Hirschberg, Phillips Robbins Feb 2012

Guanosine Diphosphatase Is Required For Protein And Sphingolipid Glycosylation In The Golgi Lumen Of Saccharomyces Cerevisiae, Claudia Abeijon, Ken Yanagisawa, Elisabet Mandon, Alex Hausler, Kelley Moremen, Carlos Hirschberg, Phillips Robbins

Elisabet Mandon

Current models for nucleotide sugar use in the Golgi apparatus predict a critical role for the lumenal nucleoside diphosphatase. After transfer of sugars to endogenous macromolecular acceptors, the enzyme converts nucleoside diphosphates to nucleoside monophosphates which in turn exit the Golgi lumen in a coupled antiporter reaction, allowing entry of additional nucleotide sugar from the cytosol. To test this model, we cloned the gene for the S. cerevisiae guanosine diphosphatase and constructed a null mutation. This mutation should reduce the concentrations of GDP-mannose and GMP and increase the concentration of GDP in the Golgi lumen. The alterations should in turn ...


Modulation Of Cyanobacterial Photosystem I Deposition Properties On Alkanethiolate Au Substrate By Various Experimental Conditions, Dibyendu Mukherjee, Michael Vaughn, Bamin Khomami, Barry Bruce Oct 2011

Modulation Of Cyanobacterial Photosystem I Deposition Properties On Alkanethiolate Au Substrate By Various Experimental Conditions, Dibyendu Mukherjee, Michael Vaughn, Bamin Khomami, Barry Bruce

Barry D. Bruce

We present results from atomic force microscopy (AFM) images indicating various experimental conditions, which alter the morphological characteristics of self-assembled cyanobacterial PS I on hydroxyl-terminated self-assembled alkanethiolate monolayers (SAM/Au) substrates. AFM topographical images of SAM/Au substrates incubated in solutions containing different PS I concentrations solubilized with Triton X-100 as the detergent reveal large columnar aggregates (∼100 nm and hence, much taller than a single PS I trimer) at high PS I concentrations. Depositions from dilute PS I suspensions reveal fewer aggregates and relatively uniform surface topography (∼10 nm). Confocal fluorescence microscopy analysis of fluorescently tagged PS I deposited ...


Optimization Of Photosynthetic Hydrogen Yield From Platinized Photosystem I Complexes Using Response Surface Methodology, Ifeyinwa Iwuchukwu, Ernest Iwuchukwu, Rosemary Le, Caitlin Paquet, Rapinder Sawhney, Barry Bruce, Paul Frymier Aug 2011

Optimization Of Photosynthetic Hydrogen Yield From Platinized Photosystem I Complexes Using Response Surface Methodology, Ifeyinwa Iwuchukwu, Ernest Iwuchukwu, Rosemary Le, Caitlin Paquet, Rapinder Sawhney, Barry Bruce, Paul Frymier

Barry D. Bruce

Light-dependent hydrogen production by platinized Photosystem I isolated from the cyanobacterium Thermosynechococcus elongatus BP-1 was optimized using response surface methodology (RSM). The process parameters studied included temperature, light intensity and wavelength, and platinum salt concentration. Application of RSM generated a model that agrees well with the data for H2 yield (R2 = 0.99 and p < 0.001). Significant effects on the total H2 yield were seen when the platinum salt concentration and temperature were varied during platinization. However, light intensity during platinization had a minimal effect on the total H2 yield within the region studied. The values of the parameters used during the platinization that optimized the production of H2 were light intensity of 240 μE m−2 s−1, platinum salt concentration of 636 μM and temperature of 31 °C. A subsequent validation experiment at the predicted conditions for optimal process yield gave the maximum H2 yield measured in the study, which was 8.02 μmol H2 per mg chlorophyll.


Antimicrobial Efficacy Of Eugenol Microemulsions In Milk Against Listeria Monocytogenes And Escherichia Coli O157:H7, S. Gaysinsky, T.M. Taylor, P.M. Davidson, Barry Bruce, J. Weiss Dec 2007

Antimicrobial Efficacy Of Eugenol Microemulsions In Milk Against Listeria Monocytogenes And Escherichia Coli O157:H7, S. Gaysinsky, T.M. Taylor, P.M. Davidson, Barry Bruce, J. Weiss

Barry D. Bruce

The antimicrobial activity of eugenol microemulsions (eugenol encapsulated in surfactant micelles) in ultrahigh-temperature pasteurized milk containing different percentages of milk fat (0, 2, and 4%) was investigated. Antimicrobial microemulsions were prepared from a 5% (wt) aqueous surfactant solution (Surfynol 485W) with 0.5% (wt) eugenol. Two strains each of Listeria monocytogenes and Escherichia coli O157:H7 previously shown to be the least and most resistant to the microemulsion in microbiological media were used to inoculate sterile milk (104 CFU/ml). Samples were withdrawn and plated at 0, 1, 3, 6, 12, and 24 h for enumeration. Microemulsions completely prevented growth ...


Structural And Functional Changes In High-Intensity Ultrasonicated Bovine Serum Albumin, I. Gulseren, D. Guzey, Barry Bruce, J. Weiss Dec 2006

Structural And Functional Changes In High-Intensity Ultrasonicated Bovine Serum Albumin, I. Gulseren, D. Guzey, Barry Bruce, J. Weiss

Barry D. Bruce

Effects of high-intensity ultrasonication on functional and structural properties of aqueous bovine serum albumin (BSA) solutions were investigated. The functional properties of BSA were altered by ultrasonication. Surface activity of BSA increased. Minimal changes were observed in the global structure of BSA but surface charge increased particularly at basic pH values (e.g. pH > 9). While dynamic light scattering measurements indicated that the particle size increased up to 3.4 times after 90 min of sonication, no significant increase in the oligomeric state of BSA using blue native PAGE was observed. The amount of free sulfhydryl groups in BSA after ...


Characterization Of Antimicrobial-Bearing Liposomes By Zeta-Potential, Vesicle Size, And Encapsulation Efficiency, T.M. Taylor, S. Gaysinsky, P.M. Davidson, Barry Bruce, J. Weiss Dec 2006

Characterization Of Antimicrobial-Bearing Liposomes By Zeta-Potential, Vesicle Size, And Encapsulation Efficiency, T.M. Taylor, S. Gaysinsky, P.M. Davidson, Barry Bruce, J. Weiss

Barry D. Bruce

Liposome entrapment may improve activity of protein or polypeptide antimicrobials against a variety of microorganisms. In this study, ability of liposomes to withstand exposure to environmental and chemical stresses typically encountered in foods and food processing operations were tested. Liposomes consisting of distearoylphosphatidylcholine (PC) and distearoylphosphatidylglycerol (PG), with 0, 5, or 10 μg/ml of the antimicrobial peptide nisin entrapped, were exposed to elevated temperatures (25–75 °C) and a range of pH (5.5–11.0). Ability of liposomes to maintain integrity was assessed by measuring the encapsulation efficiency (EE), ζ-potential, and particle size distribution of liposomes. Distearoylphosphatidylcholine, PC ...


In Vitro Comparative Kinetic Analysis Of The Chloroplast Toc Gtpases, E.L. Reddick, M. Vaughn, S.J. Wright, I. Campbell, Barry Bruce Dec 2006

In Vitro Comparative Kinetic Analysis Of The Chloroplast Toc Gtpases, E.L. Reddick, M. Vaughn, S.J. Wright, I. Campbell, Barry Bruce

Barry D. Bruce

A unique aspect of protein transport into plastids is the coordinate involvement of two GTPases in the translocon of the outer chloroplast membrane (Toc). There are two subfamilies in Arabidopsis, the small GTPases (Toc33 and Toc34) and the large acidic GTPases (Toc90, Toc120, Toc132, and Toc159). In chloroplasts, Toc34 and Toc159 are implicated in precursor binding, yet mechanistic details are poorly understood. How the GTPase cycle is modulated by precursor binding is complex and in need of careful dissection. To this end, we have developed novel in vitro assays to quantitate nucleotide binding and hydrolysis of the Toc GTPases. Here ...


A Simple Atomic Force Microscopy Method The Visualization Of Polar And Non-Polar Parts Organic Films, A.A. Yu, P.R. Stoney, J.E. Norvillez, M. Vaughn, E.J. Pascial, Barry Bruce, M. Baldo, F. Stellacci Dec 2005

A Simple Atomic Force Microscopy Method The Visualization Of Polar And Non-Polar Parts Organic Films, A.A. Yu, P.R. Stoney, J.E. Norvillez, M. Vaughn, E.J. Pascial, Barry Bruce, M. Baldo, F. Stellacci

Barry D. Bruce

Here we present a scanning probe microscopy method that allows for the identification of regions of different polarity (i.e. hydrophilicity) in thin organic films. This technique is based on the analysis of the difference between phase images generated at different applied bias voltages in tapping-mode atomic force microscopy. We show that, without any chemical modification of the microscope tip, it is possible to investigate surface properties of complex macromolecular layers, yielding new insight into the functional properties of the photosynthetic electron transport macromolecular complex, Photosystem I.


Interfacial Properties And Structural Conformation Of Thermosonicated Bovice Serum Albumin, D. Guzey, I. Gulseren, Barry Bruce, J. Weiss Dec 2005

Interfacial Properties And Structural Conformation Of Thermosonicated Bovice Serum Albumin, D. Guzey, I. Gulseren, Barry Bruce, J. Weiss

Barry D. Bruce

Aqueous Bovine Serum Albumin (BSA) solutions were treated with high-intensity ultrasound (20 W cm−2) for 15, 30 and 45 min at temperatures of up to 85 °C. The equilibrium and dynamic surface tension of native and ultrasonicated BSA at the air-solution interface was measured using drop shape analysis. The effect of ultrasound on the secondary structure of BSA was monitored by circular dichroism spectroscopy. Surface pressure of BSA at the air-solvent interface increased as a consequence of sonication treatment at 20 °C. Both the rate of surface pressure increase and the equilibrium surface pressure of sonicated BSA were significantly ...


Ultrasonic Spectroscopy And Differential Scanning Calorimetry Of Liposomal Encapsulated Nisin, M.T. Taylor, P.M. Davidson, Barry Bruce, J. Weiss Dec 2004

Ultrasonic Spectroscopy And Differential Scanning Calorimetry Of Liposomal Encapsulated Nisin, M.T. Taylor, P.M. Davidson, Barry Bruce, J. Weiss

Barry D. Bruce

The thermal stability of phosphatidylcholine (PC) liposomes (colloidal dispersions of bilayer-forming polar lipids in aqueous solvents) in the presence and absence of the antimicrobial polypeptide nisin was evaluated using differential scanning calorimetry (DSC) and low-intensity ultrasonic spectroscopy (US). PC liposome mixtures with varying acyl chain lengths (C16:0 and C18:0) were formed in buffer with or without entrapped nisin. Gel-to-liquid crystalline phase transition temperatures (TM) of liposomes determined from DSC thermograms were in excellent agreement with those determined by ultrasonic velocity and attenuation coefficient measurements recorded at 5 MHz. The dipalmitoylphosphatidylcholine (DPPC) TM measured by DSC was ...


Liposomal Nanocapsules In Food Science And Agriculture, T.M. Taylor, P.M. Davidson, Barry Bruce, J. Weiss Dec 2004

Liposomal Nanocapsules In Food Science And Agriculture, T.M. Taylor, P.M. Davidson, Barry Bruce, J. Weiss

Barry D. Bruce

Liposomes, spherical bilayer vesicles from dispersion of polar lipids in aqueous solvents, have been widely studied for their ability to act as drug delivery vehicles by shielding reactive or sensitive compounds prior to release. Liposome entrapment has been shown to stabilize encapsulated, bioactive materials against a range of environmental and chemical changes, including enzymatic and chemical modification, as well as buffering against extreme pH, temperature, and ionic strength changes. Liposomes have been especially useful to researchers in studies of various physiological processes as models of biological membranes in both eukaryotes and prokaryotes. Industrial applications include encapsulation of pharmaceuticals and therapeutics ...


The Paradox Of Plastid Transit Peptides: Conservation Of Function Despite Divergence In Primary Structure, Barry Bruce Dec 2000

The Paradox Of Plastid Transit Peptides: Conservation Of Function Despite Divergence In Primary Structure, Barry Bruce

Barry D. Bruce

Transit peptides are N-terminal extensions that facilitate the targeting and translocation of cytosolically synthesized precursors into plastids via a post-translational mechanism. With the complete Arabidopsis genome in hand, it is now evident that transit peptides direct more than 3500 different proteins into the plastid during the life of a typical plant. Deciphering a common mechanism for how this multitude of targeting sequences function has been hampered by the realization that at a primary sequence level, transit peptides are highly divergent in length, composition, and organization. This review addresses recent findings on several of the diverse functions that transit peptides must ...


Chloroplast Transit Peptides: Structure, Function, And Evolution, Barry Bruce Dec 1999

Chloroplast Transit Peptides: Structure, Function, And Evolution, Barry Bruce

Barry D. Bruce

It is thought that two to three thousand different proteins are targeted to the chloroplast, and the ‘transit peptides’ that act as chloroplast targeting sequences are probably the largest class of targeting sequences in plants. At a primary structural level, transit peptide sequences are highly divergent in length, composition and organization. An emerging concept suggests that transit peptides contain multiple domains that provide either distinct or overlapping functions. These functions include direct interaction with envelope lipids, chloroplast receptors and the stromal processing peptidase. The genomic organization of transit peptides suggests that these domains might have originated from distinct exons, which ...