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Organismal Biological Physiology Commons

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2012

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Articles 1 - 8 of 8

Full-Text Articles in Organismal Biological Physiology

The Mycoplasma Genitalium Mg_454 Gene Product Resists Killing By Organic Hydroperoxides, Sankaralingam Saikolappan, Smitha Sasindran, Hongwei Yu, Joel Basema, Subramanian Dhandayuthapani Aug 2012

The Mycoplasma Genitalium Mg_454 Gene Product Resists Killing By Organic Hydroperoxides, Sankaralingam Saikolappan, Smitha Sasindran, Hongwei Yu, Joel Basema, Subramanian Dhandayuthapani

Hongwei Yu

Mycoplasma genitalium is the smallest self-replicating organism and a successful human pathogen associated with a range of genitourinary maladies. As a consequence of its restricted genome size, genes that are highly conserved in other bacteria are absent in M. genitalium. Significantly, genes that encode antioxidants like superoxide dismutase and catalase-peroxidase are lacking. Nevertheless, comparative genomics has revealed that MG_454 of M. genitalium encodes a protein with putative function as an organic hydroperoxide reductase (Ohr). In this study, we found that an M. genitalium transposon mutant that lacks expression of MG_454 was sensitive to killing by t-butyl hydroperoxide and cumene hydroperoxide. …


Lipotoxin F Of Pseudomonas Aeruginosa Is An Algu-Dependent And Alginate-Independent Outer Membrane Protein Involved In Resistance To Oxidative Stress And Adhesion To A549 Human Lung Epithelia, F. Damron, Jennifer Napper, M. Teter, Hongwei Yu Aug 2012

Lipotoxin F Of Pseudomonas Aeruginosa Is An Algu-Dependent And Alginate-Independent Outer Membrane Protein Involved In Resistance To Oxidative Stress And Adhesion To A549 Human Lung Epithelia, F. Damron, Jennifer Napper, M. Teter, Hongwei Yu

Hongwei Yu

Chronic lung infection with P. aeruginosa and excessive neutrophil-associated inflammation are major causes of morbidity and mortality in patients with cystic fibrosis (CF). Overproduction of an exopolysaccharide known as alginate leads to the formation of mucoid biofilms that are resistant to antibiotics and host defences. Alginate overproduction or mucoidy is controlled by a stress-related ECF sigma factor AlgU/T. Mutation in the anti-sigma factor MucA is a known mechanism for conversion to mucoidy. Recently, we showed that inactivation of a kinase (KinB) in nonmucoid strain PAO1 results in overproduction of alginate. Here, we report the initial characterization of lipotoxin F (LptF, …


Characterization Of Chemosensing In The Alphaproteobacterium Azospirillum Brasilense , Matthew Hamilton Russell Aug 2012

Characterization Of Chemosensing In The Alphaproteobacterium Azospirillum Brasilense , Matthew Hamilton Russell

Doctoral Dissertations

Motile bacteria must navigate their environment in constant search of nutrients to sustain life. Thus they have evolved precise and adaptable sensory systems to achieve this goal, making the navigation system of the model bacterium Escherichia coli the best characterized signal transduction pathway in Biology. However, many bacteria have evolved more sophisticated arsenals for sensing and responding to their environment including chemoreceptors to identify novel attractants in the microenvironment. The diazotrophic alphaproteobacterium Azospirillum brasilense inhabits the soil and colonizes the roots of cereals like rice, corn, and wheat. Like most proteobacterial, A. brasilense encodes multiple chemotaxis-like pathways, 4, of which …


Cell Bioenergetics In Leghorn Male Hepatoma Cells And Immortalized Chicken Liver Cells In Response To 4-Hydroxynonenal Induced Oxidative Stress, Alissa Laura Piekarski Aug 2012

Cell Bioenergetics In Leghorn Male Hepatoma Cells And Immortalized Chicken Liver Cells In Response To 4-Hydroxynonenal Induced Oxidative Stress, Alissa Laura Piekarski

Graduate Theses and Dissertations

Bioenergetic mechanisms responsible for ATP production are essential in carrying out maintenance and cell-specific functions. In this study, hepatocytes (liver cells) were used to test both endogenous and exogenous stress on cellular respiration. The secondary lipid peroxide, 4-hydroxynonenal (HNE), was used because it alters bioenergetics by increasing mitochondrial proton leak that attenuates mitochondrial radical production and, therefore, endogenous oxidative stress. The major objective of this study was to demonstrate effects of HNE-induced oxidative stress on avian hepatocyte bioenergetics. Various chemical which help enable the determination of oxygen (O2) consumption linked to ATP synthesis (oligomycin), maximal O2 consumption (FCCP), and proton …


Sea Slug—Algal Chloroplast Symbiosis: Towards An Integrated Understanding Of Long-Term Chloroplast Functioning In An Animal, Mary E. Rumpho May 2012

Sea Slug—Algal Chloroplast Symbiosis: Towards An Integrated Understanding Of Long-Term Chloroplast Functioning In An Animal, Mary E. Rumpho

University of Maine Office of Research Administration: Grant Reports

Photosynthesis plays a fundamental role in understanding plant growth and productivity. The chloroplast, the organelle of photosynthesis, evolved following the endosymbiotic uptake of a cyanobacterium and massive gene transfer. As a result, the chloroplast is highly dependent upon nuclear genes to provide essential chloroplast proteins. A special form of endosymbiosis, kleptoplasty, has evolved in the marine mollusc Elysia chlorotica. This green, leaf-like animal carries out photosynthesis for its entire ten month life-cycle, as if it were a plant, by using chloroplasts it steals and retains from the alga Vaucheria litorea. It is highly likely that horizontal gene transfer (HGT) has …


Links From Mantle To Microbe At The Lau Integrated Study Site: Insights From A Back-Arc Spreading Center, Margaret K. Tivey, Erin Becker, Roxanne Beinart, Charles R. Fisher, Peter Girguis, Charles H. Langmuir, Peter J. Michael, Anna-Louise Reysenbach Mar 2012

Links From Mantle To Microbe At The Lau Integrated Study Site: Insights From A Back-Arc Spreading Center, Margaret K. Tivey, Erin Becker, Roxanne Beinart, Charles R. Fisher, Peter Girguis, Charles H. Langmuir, Peter J. Michael, Anna-Louise Reysenbach

Biology Faculty Publications and Presentations

The Lau Integrated Study Site (ISS) has provided unique opportunities for study of ridge processes because of its back-arc setting in the southwestern Pacific. Its location allows study of a biogeographical province distinct from those of eastern Pacific and mid-Atlantic ridges, and crustal compositions along the ridge lie outside the range of mid-ocean ridge crustal compositions. The Lau ISS is located above a subduction zone, at an oblique angle. The underlying mantle receives water and other elements derived from the downgoing lithospheric slab, with an increase in slab influence from north to south. Water lowers the mantle melting temperature and …


Thoughts On Quorum Sensing And Fungal Dimorphism, Kenneth W. Nickerson, Audrey L. Atkin, Jessica C. Hargarten, Ruvini U. Pathirana, Sahar Hasim Jan 2012

Thoughts On Quorum Sensing And Fungal Dimorphism, Kenneth W. Nickerson, Audrey L. Atkin, Jessica C. Hargarten, Ruvini U. Pathirana, Sahar Hasim

Papers in Microbiology

Farnesol has been best studied for its role in regulating fungal dimorphism. However, farnesol is also a lipid and in this review we analyze data relevant to farnesol’s function and synthesis from the perspective of farnesol and bacterial endotoxins acting as membrane active compounds. This analysis implicates the possible roles of: (1) endotoxins in the regulation of farnesol production by C. albicans; (2) farnesol in the interactions between C. albicans and the host during disseminated infections; and (3) ubiquinones in the mechanisms for unusually high resistance to farnesol by some C. albicans cell types. Finally we discuss the implications …


Parasites Of Civets (Mammalia, Viverridae) In Sabah, Borneo: A Coprological Survey, Christina P. Colon, Sharon Patton Jan 2012

Parasites Of Civets (Mammalia, Viverridae) In Sabah, Borneo: A Coprological Survey, Christina P. Colon, Sharon Patton

Publications and Research

Parasite data were collected from unlogged and selectively logged lowland rain forests in Borneo. Scat from a female Viverra tangalunga (Malay civet) in the unlogged forest contained eggs of Capillaria spp., Trichuris sp., Mamomoganomus sp., and nematode larvae. Scat attributed to V. tangalunga contained reproductive products (eggs/oocysts/cysts/larvae) of Capillaria sp., Toxocara sp., Ancylostoma sp. (probably A. ceylanicum), Isospora spp., strongylate-type eggs (probably Ancylostoma spp.), Paragoni­ mus sp. and other Trematoda eggs, Monocystis sp. cysts, Gnathostoma sp. (probably G. spinigerum), the lungworm Viverrostrongylus brauni, pinworm-type eggs, Eimeria spp., Sarcocystis-type sporocyst, dermanysid mites and mesostigmatid mites. Parasites from gut samples from two …