Open Access. Powered by Scholars. Published by Universities.®

Biochemistry, Biophysics, and Structural Biology Commons™

Open Access. Powered by Scholars. Published by Universities.®

Biochemistry

Bacteria

Institution
Publication Year
Publication
Publication Type

Articles 1 - 30 of 34

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Growth, Yield, And Photosynthetic Dry Matter Remobilization Response Of Barley To Plant Growth Promoting Rhizobacteria (Pgpr) And Nitrogen, Abazar Abbasi, Shahram Mehri, Hossein Solimanzadeh, Saeid Alipour Dec 2023

Growth, Yield, And Photosynthetic Dry Matter Remobilization Response Of Barley To Plant Growth Promoting Rhizobacteria (Pgpr) And Nitrogen, Abazar Abbasi, Shahram Mehri, Hossein Solimanzadeh, Saeid Alipour

The Philippine Agricultural Scientist

A two-year factorial experiment based on a randomized complete block design with three replicates was carried out on barley cultivar LB-IRAN at the research farm of the Islamic Azad University, Ardabil, Iran, during the cropping years of 2019–2021, in order to survey the impact of plant growth-promoting rhizobacteria (PGPR) and nitrogen fertilizer on growth, yield, and remobilization of photosynthetic dry matter in barley. The first factor included five nitrogen levels: 0 (control), 25, 50, 75, 100 kg/ha net nitrogen; the second factor contained grain inoculations with four bacteria: no inoculation (control), Azotobacter chroococcum race 5, Azospirillum lipoferum race of, and …

Go to article

The Role Of Cerium(Iii) In Bacterial Growth And The Microbial Transformation Of Aromatic Hydrocarbons, Shruti Sathish Apr 2023

The Role Of Cerium(Iii) In Bacterial Growth And The Microbial Transformation Of Aromatic Hydrocarbons, Shruti Sathish

Honors Theses

Biofilms are communities of surface-attached bacterial cells encased in an exopolymeric matrix. In this state, they are more resistant to antimicrobial treatment and can have adverse effects in medical, agricultural, and industrial settings. Whereas, as biocatalysts, biofilms from nonpathogenic bacteria enhance their performance and stability in catalysis. Unfortunately, there are several challenges when using bacteria in organic transformations due to their complex cellular chemistry. Trivalent lanthanide metals were discovered to serve regulatory roles in some bacterial catalytic processes, including those of Pseudomonas putida KT2440 (P. putida), a non-infectious Gram-negative bacterium. The main goal of our research is to use cerium(III) …

Go to article

Characterization Of The Clostridioides Difficile Glycosyl Hydrolase Ccsz, Brian Lowrance Jan 2023

Characterization Of The Clostridioides Difficile Glycosyl Hydrolase Ccsz, Brian Lowrance

Theses and Dissertations (Comprehensive)

Bacteria inhabit many of the harshest environments on Earth; persisting and thriving in conditions thought to be unsuitable for life. One common strategy to withstand these environments is the formation of a biofilm. Biofilm composition varies greatly, depending on the underlying community that produces it. Cellulose, a polymer consistently prevalent in biofilms, has been identified as a virulence factor in many pathogens and is suspected to be involved in pathogenesis by Clostridioides difficile. C. difficile is the #1 cause of hospital acquired diarrhea, which can range from mild to life-threatening infections. Biofilm formation is hypothesized to be involved in …

Go to article

Biodegradation Of Rubber Particles In Soil: Using Acclimated Bacteria Isolated From Kansas Soil To Degrade Cryogrinds In Slurry, Shane Graham Jan 2022

Biodegradation Of Rubber Particles In Soil: Using Acclimated Bacteria Isolated From Kansas Soil To Degrade Cryogrinds In Slurry, Shane Graham

Williams Honors College, Honors Research Projects

This study investigated the viability of bioremediating rubber cryogrind using enriched indigenous bacteria. To begin the experiment, soils from three highway roadside locations in Kansas, KS 96 and West, KS 400 and 143rd, and 199th, were collected and transported to the lab to be studied. An initial soil characterization was run on the soil samples using distilled (DI) water mixture and 0.01 M CaCl2 to assess conductivity. The soils were tested to gather a baseline of the relationship between pH and conductivity and the impact of its distance from the roadside. Bacteria were isolated from …

Go to article

Discovering Virally Encoded Proteins That Block Type Iv Crispr Immune Systems, Andrew Williams Dec 2021

Discovering Virally Encoded Proteins That Block Type Iv Crispr Immune Systems, Andrew Williams

Fall Student Research Symposium 2021

Bacteria and the viruses that infect them have been at war from the beginnings of life until today. Due to selective pressure from viral infection, bacteria have evolved various biological defense systems, including CRISPR-Cas systems that use a genetic memory of previous viral encounters to protect against future invasions. However, recently it has been shown that viruses have evolved counter-strategies to evade CRISPR systems. Virally encoded proteins called anti-CRISPRs use a variety of mechanisms to block the activity of CRISPR immune systems in order to infect bacterial cells. The Jackson lab at USU recently showed that a Type IV-A CRISPR-Cas …

Go to article

The Flavoprotein Rcla Is A Hypothiocyanous Acid Reductase, Irina Chapman Dec 2021

The Flavoprotein Rcla Is A Hypothiocyanous Acid Reductase, Irina Chapman

Masters Theses

Reactive chlorine species (RCS) - hypochlorous acid (HOCl), hypothiocyanous acid (HOSCN), and chloramines - are powerful antimicrobial oxidants generated by the innate immune system. Bacteria developed defense mechanisms against RCS, which are highly toxic for invading pathogens. One such defense system involves RclA, an enzyme from the flavin disulfide reductase family, which is massively upregulated upon exposure of Escherichia coli to RCS. Recent research suggests that RclA functions as a Cu(II) reductase to provide resistance against RCS. However, the exact mechanism used by RclA was subject to debate. In this study, we demonstrate that RclA is unlikely to function as …

Go to article

Determination Of The Structure, Function, And Mechanism Of Type Iv Crispr-Cas Prokaryotic Defense Systems, Hannah Nicole Taylor Aug 2021

Determination Of The Structure, Function, And Mechanism Of Type Iv Crispr-Cas Prokaryotic Defense Systems, Hannah Nicole Taylor

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bacteria are under constant threat of invasion by bacteriophage (viruses which infect bacteria). To prevent bacteriophage from entering and overtaking the bacteria, bacteria utilize defense systems to identify and destroy foreign elements. One method of defense is called CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats – CRISPR-Associated). Many different bacteria and most archaea use CRISPR-Cas systems. There are many diverse types of CRISPR-Cas systems, each of which provides defense in a slightly different way. One such CRISPR-Cas type is called type IV. The type IV CRISPR-Cas system is poorly understood and there are very few studies published on type IV …

Go to article

Probing Interactions Between Canonical Nox Domains, Akua Acheampong May 2021

Probing Interactions Between Canonical Nox Domains, Akua Acheampong

Master of Science in Integrative Biology Theses

NAPDH oxidase enzymes (NOXes) reduce molecular oxygen to superoxide and other ROS. NOXes contain a catalytic core comprising a heme-containing transmembrane (TM) domain and a cytoplasmic dehydrogenase (DH) domain that binds the substrate NADPH and the cofactor. Previously, NOXes were only characterized in eukaryotes, but have recently been identified in prokaryotes, namely bacteria. Due to their constitutive activity and solubility in detergent, bacterial NOXes, such as Streptococcus Pneumoniae NOX, have emerged as a model for studying NOXes. Past research studies in NOXes have identified conserved, putative interacting regions at the interface of the TM and DH domains: the TM B-loop, …

Go to article

Metabolic Feedback Inhibition Influences Metabolite Secretion By The Human Gut Symbiont Bacteroides Thetaiotaomicron, Jennie L. Catlett, Jonathan Catazaro, Mikaela Cashman, Sean Carr, Robert Powers, Myra B. Cohen, Nicole R. Buan Jan 2020

Metabolic Feedback Inhibition Influences Metabolite Secretion By The Human Gut Symbiont Bacteroides Thetaiotaomicron, Jennie L. Catlett, Jonathan Catazaro, Mikaela Cashman, Sean Carr, Robert Powers, Myra B. Cohen, Nicole R. Buan

Department of Biochemistry: Faculty Publications

Microbial metabolism and trophic interactions between microbes give rise to complex multispecies communities in microbe-host systems. Bacteroides thetaiotaomicron (B. theta) is a human gut symbiont thought to play an important role in maintaining host health. Untargeted nuclear magnetic resonance metabolomics revealed B. theta secretes specific organic acids and amino acids in defined minimal medium. Physiological concentrations of acetate and formate found in the human intestinal tract were shown to cause dose-dependent changes in secretion of metabolites known to play roles in host nutrition and pathogenesis. While secretion fluxes varied, biomass yield was unchanged, suggesting feedback inhibition does not affect metabolic …

Go to article

Functional Similarity Of Prd-Containing Virulence Regulators In Bacillus Anthracis, Malik Raynor May 2018

Functional Similarity Of Prd-Containing Virulence Regulators In Bacillus Anthracis, Malik Raynor

Dissertations & Theses (Open Access)

Bacillus anthracis produces three regulators, AtxA, AcpA, and AcpB, that control virulence gene expression and are members of an emerging class of regulators termed “PCVRs” (Phosphoenolpyruvate-dependent phosphotransferase regulation Domain-Containing Virulence Regulators). AtxA controls expression of the toxin genes; lef, cya, and pag, and is the master virulence regulator and archetype PCVR. AcpA and AcpB are less well studied. AcpA and AcpB independently positively control transcription of the capsule biosynthetic operon capBCADE, and culture conditions that enhance AtxA activity result in capBCADE transcription in strains lacking acpA and acpB. RNA-Seq was used to assess the regulons of the …

Go to article

Assay Of The Reverse Osmosis Purified Water In The Life Science Building At Bowling Green State University, Ohio, Nicholas Mendenhall, Scott O. Rogers, Neocles B. Leontis Apr 2018

Assay Of The Reverse Osmosis Purified Water In The Life Science Building At Bowling Green State University, Ohio, Nicholas Mendenhall, Scott O. Rogers, Neocles B. Leontis

Honors Projects

Contaminated water sources can cause problems for scientific research and result in costly delays and failures of experiments. At Bowling Green State University, the reverse osmosis supply circulating in the Life Sciences Building has been measurably contaminated for nearly three years, corresponding to a change in servicing of the system. While servicing has been accelerated, the contamination in the system remains. The focus of this research was to identify the species of bacteria and fungi growing inside of the water system so that it might alert those servicing the system, and to begin to eliminate the contamination. Reverse osmosis water …

Go to article

Pore Forming Protein Assembly And The Use In Nanopore Sensing: A Study On E. Coli Proteins Clya And Ompg, Monifa Fahie Nov 2017

Pore Forming Protein Assembly And The Use In Nanopore Sensing: A Study On E. Coli Proteins Clya And Ompg, Monifa Fahie

Doctoral Dissertations

Pore forming proteins are typically the proteins that form channels in membranes. They have several roles ranging from molecule transport to triggering the death of a cell. This work focuses on two E. coli pore forming proteins that have vastly differing roles in nature. Outer membrane protein G (OmpG) is an innocuous β-barrel porin while Cytolysin A (ClyA) is an α-helical pore forming toxin. For OmpG we probed its potential to be a nanopore sensor for protein detection and quantification. A small high affinity ligand, biotin, was covalently attached to loop 6 of OmpG and used to capture biotin-binding proteins. …

Go to article

Defining Electron Bifurcation In The Electron-Transferring Flavoprotein Family, Amaya M. Garcia Costas, Saroj Poudel, Anne-Frances Miller, Gerrit J. Schut, Rhesa N. Ledbetter, Kathryn R. Fixen, Lance C. Seefeldt, Michael W. W. Adams, Caroline S. Harwood, Eric S. Boyd, John W. Peters Nov 2017

Defining Electron Bifurcation In The Electron-Transferring Flavoprotein Family, Amaya M. Garcia Costas, Saroj Poudel, Anne-Frances Miller, Gerrit J. Schut, Rhesa N. Ledbetter, Kathryn R. Fixen, Lance C. Seefeldt, Michael W. W. Adams, Caroline S. Harwood, Eric S. Boyd, John W. Peters

Chemistry Faculty Publications

Electron bifurcation is the coupling of exergonic and endergonic redox reactions to simultaneously generate (or utilize) low- and high-potential electrons. It is the third recognized form of energy conservation in biology and was recently described for select electron-transferring flavoproteins (Etfs). Etfs are flavin-containing heterodimers best known for donating electrons derived from fatty acid and amino acid oxidation to an electron transfer respiratory chain via Etf-quinone oxidoreductase. Canonical examples contain a flavin adenine dinucleotide (FAD) that is involved in electron transfer, as well as a non-redox-active AMP. However, Etfs demonstrated to bifurcate electrons contain a second FAD in place of the …

Go to article

Enhancement Of Reactive Oxygen Species Production And Chlamydial Infection By The Mitochondrial Nod-Like Family Member Nlrx1, Ali A. Abdul-Sater, Najwene Saïd-Sadier, Verissa M. Lam, Bhavni Singh, Matthew A. Pettengill, Fraser Soares, Ivan Tattoli, Simone Lipinski, Stephen E. Girardin, Philip Rosenstiel, David M. Ojcius Apr 2017

Enhancement Of Reactive Oxygen Species Production And Chlamydial Infection By The Mitochondrial Nod-Like Family Member Nlrx1, Ali A. Abdul-Sater, Najwene Saïd-Sadier, Verissa M. Lam, Bhavni Singh, Matthew A. Pettengill, Fraser Soares, Ivan Tattoli, Simone Lipinski, Stephen E. Girardin, Philip Rosenstiel, David M. Ojcius

David M. Ojcius

Chlamydia trachomatis infections cause severe and irreversible damage that can lead to infertility and blindness in both males and females. Following infection of epithelial cells, Chlamydia induces production of reactive oxygen species (ROS). Unconventionally, Chlamydiae use ROS to their advantage by activating caspase-1, which contributes to chlamydial growth. NLRX1, a member of the Nod-like receptor family that translocates to the mitochondria, can augment ROS production from the mitochondria following Shigella flexneri infections. However, in general, ROS can also be produced by membrane-bound NADPH oxidases. Given the importance of ROS-induced caspase-1 activation in growth of the chlamydial vacuole, we investigated the …

Go to article

Mutagenic And Spectroscopic Investigation Of Ph Dependent Cooa Dna Binding, Brian R. Weaver Apr 2017

Mutagenic And Spectroscopic Investigation Of Ph Dependent Cooa Dna Binding, Brian R. Weaver

Chemistry Honors Papers

The carbon monoxide (CO) sensing heme protein, CooA, is a transcription factor which exists in several bacteria that utilize CO as an energy source. CooA positively regulates the expression of coo genes in the presence of CO such that the corresponding proteins may metabolize CO. The present studies have yielded the unexpected result that Fe(III) CooA binds DNA tightly at pH < 7, deviating from all previously reported work which indicate that CooA DNA binding is initiated only when the exogenous CO effector reacts with the Fe(II) CooA heme. This observation suggests that the disruption of one or more salt bridges upon effector binding may be a critical feature of the normal CooA activation mechanism. To test this possibility, several protein variants that eliminated a selected salt bridge for the CooA homolog from Rhodospirillum rubrum were prepared via site-directed mutagenesis. Samples of these variant proteins, which were overexpressed in Escherichia coli, were then characterized by spectroscopic methods and functional assays to investigate the impact these mutations had on CooA heme coordination …

Go to article

Novel Approaches To Mitigating Bacterial Biofilm Formation And Intercellular Communication, Stephen Kasper Jan 2017

Novel Approaches To Mitigating Bacterial Biofilm Formation And Intercellular Communication, Stephen Kasper

Legacy Theses & Dissertations (2009 - 2024)

Long thought of as solitary single-cell organisms, it is now widely accepted that bacteria can act and cooperate as social organisms. Phenomena such as biofilm formation and quorum sensing (QS) are two intimately intertwined cooperative behaviors that significantly contribute to the pathogenesis of many bacteria. Biofilms are surface associated communities of bacteria encased in a secreted extracellular matrix, which provides several advantages over an individualized lifestyle, such as increased protection from antimicrobial agents as well as enhanced opportunity for the exchange of genetic material. Bacterial QS is a system of population-based communication through the production, sensing, and response to chemical …

Go to article

The Effect Of Pure Infrared Light On The Growth Of Rhodospirrilum Rubrum, Jordan Lee Wilkes May 2016

The Effect Of Pure Infrared Light On The Growth Of Rhodospirrilum Rubrum, Jordan Lee Wilkes

Undergraduate Honors Capstone Projects

Scientists who study aquatic ecosystems quickly notice a diversity of pathways that different microbes and organisms can use to metabolize nutrients found in common ponds or pools. Competition for vital resources, such as light and inorganic minerals, allow only certain organisms to grow in certain niches within these ecosystems. Rhodospirillum rubrum is a gram negative, photosynthetic bacteria that competes for light within aquatic ecosystems in order to survive. R. rubrum is believed to specifically absorb light for photosynthesis at wavelengths in the range of infrared light. It was found that R. rubrum indeed can grow in "dark", anaerobic environments by …

Go to article

Image-Charge Detection €“ Novel Instrumentation And Applications, Brandon Lee Barney Oct 2015

Image-Charge Detection €“ Novel Instrumentation And Applications, Brandon Lee Barney

Theses and Dissertations

Image-charge detection is an analytical technique in which a highly-charged particle is detected by the magnitude of the image current that it generates in a detecting electrode. This current is represented as a voltage between the charged particle and the sensing electrode. It is a single particle detection method, ideal for the analysis of large, variable mass particles such as biological cells. Some of the physical properties of Bacillus subtilis spores were explored using different applications of image-charge detection. B. subtilis is a gram-negative spore-forming bacteria that has been shown to exhibit extremophile behavior. The particular extremophile behavior that was …

Go to article

Purification And Characterization Of Bcsc; An Integral Component Of Bacterial Cellulose Export, Emily D. Wilson Ms Jan 2015

Purification And Characterization Of Bcsc; An Integral Component Of Bacterial Cellulose Export, Emily D. Wilson Ms

Theses and Dissertations (Comprehensive)

Biofilms are a growing concern in the medical field due to their increased resistance to antibiotics. When found in a biofilm, bacteria can have antibiotic resistance 10-1000 times that of their planktonic counterparts. Therefore, it is important to study the formation of biofilms. Cellulose biofilms are formed by Enterobacteriaceae, such as many Escherichia coli and Salmonella spp. strains. Biofilms provide these species with benefits including antimicrobial protection, development of bacterial communities, promotion of DNA exchange, uptake of nutrients, and, in the case of cellulose biofilms, immune system evasion. Cellulose biofilms are controlled by the Bacterial cellulose synthesis (Bcs) complex located …

Go to article

Antimicrobial And Antiinsectan Phenolic Metabolites Of Dalea Searlsiae, Gil Belofsky, Mario Aronica, Eric Foss, Jane Diamond, Felipe Santana, Jacob Darley, Patrick F. Dowd, Christina M. Coleman, Daneel Ferreira Apr 2014

Antimicrobial And Antiinsectan Phenolic Metabolites Of Dalea Searlsiae, Gil Belofsky, Mario Aronica, Eric Foss, Jane Diamond, Felipe Santana, Jacob Darley, Patrick F. Dowd, Christina M. Coleman, Daneel Ferreira

All Faculty Scholarship for the College of the Sciences

Continued interest in the chemistry of Dalea spp. led to investigation of Dalea searlsiae, a plant native to areas of the western United States. Methanol extractions of D. searlsiae roots and subsequent chromatographic fractionation afforded the new prenylated and geranylated flavanones malheurans A–D (1–4) and known flavanones (5 and 6). Known rotenoids (7 and 8) and isoflavones (9 and 10) were isolated from aerial portions. Structure determination of pure compounds was accomplished primarily by extensive 1D- and 2D-NMR spectroscopy. The absolute configurations of compounds 1–5, 7 …

Go to article

Microfluidic Electrical Sorting Of Particles Based On Shape In A Spiral Microchannel, John Dubose, Xinyu Lu, Saurin Patel, Shizhi Qian, Sang Woo Joo Jan 2014

Microfluidic Electrical Sorting Of Particles Based On Shape In A Spiral Microchannel, John Dubose, Xinyu Lu, Saurin Patel, Shizhi Qian, Sang Woo Joo

Mechanical & Aerospace Engineering Faculty Publications

Shape is an intrinsic marker of cell cycle, an important factor for identifying a bioparticle, and also a useful indicator of cell state for disease diagnostics. Therefore, shape can be a specific marker in label-free particle and cell separation for various chemical and biological applications. We demonstrate in this work a continuous-flow electrical sorting of spherical and peanut-shaped particles of similar volumes in an asymmetric double-spiral microchannel. It exploits curvature-induced dielectrophoresis to focus particles to a tight stream in the first spiral without any sheath flow and subsequently displace them to shape-dependent flow paths in the second spiral without any …

Go to article

An Ethnobotanical Approach To Finding Antimicrobial Compounds In Wooly Blue Curls (Trichostema Lanatum) Using A Kirby-Bauer Disc Diffusion Assay, Matthew C. Fleming, P. Matthew Joyner Jul 2013

An Ethnobotanical Approach To Finding Antimicrobial Compounds In Wooly Blue Curls (Trichostema Lanatum) Using A Kirby-Bauer Disc Diffusion Assay, Matthew C. Fleming, P. Matthew Joyner

Featured Research

Plants can be an important source of creativity and production of new drugs. In this study, extracts of wooly blue curls (Trichostema lanatum) were made using DMSO and tested for antimicrobial activity on a panel of bacteria commonly found in separate ecological niches. Wooly blue curls (WBC) was chosen due to its being recorded as a strong disinfectant by the Chumash people. It was found that WBC does exhibit antimicrobial activity against gram positive bacteria and not against gram negative bacteria. However, gram negative bacteria with reduced drug efflux function became susceptible to the WBC extract.

Go to article

Host Pathogen Interactions: Is Arabidopsis Thaliana Remembered By Its Nemesis Pseudomonas Syringae?, Daniel Z. Kreiser May 2012

Host Pathogen Interactions: Is Arabidopsis Thaliana Remembered By Its Nemesis Pseudomonas Syringae?, Daniel Z. Kreiser

Lawrence University Honors Projects

Plants contain innate immune systems that deter pathogen infection. Pattern recognition receptors bind microbe-associated molecular patterns (MAMPs), triggering immunity. MAMPs are proteins exclusive to pathogens that are typically indispensable for their survival. For this reason, MAMPs cannot be mutated or removed without causing pathogen death. However, this does not necessitate constitutive expression of MAMPs. In this study, the MAMP response of Arabidopsis thaliana was utilized to determine differential detection of MAMPs expressed by Pseudomonas syringe pv. tomato DC3000 when pretreated with A. thaliana. Results demonstrated that more MAMPs are detected when P. syringae had previously encountered A. thaliana, …

Go to article

Enhancement Of Reactive Oxygen Species Production And Chlamydial Infection By The Mitochondrial Nod-Like Family Member Nlrx1, Ali A. Abdul-Sater, Najwene Saïd-Sadier, Verissa M. Lam, Bhavni Singh, Matthew A. Pettengill, Fraser Soares, Ivan Tattoli, Simone Lipinski, Stephen E. Girardin, Philip Rosenstiel, David M. Ojcius Dec 2010

Enhancement Of Reactive Oxygen Species Production And Chlamydial Infection By The Mitochondrial Nod-Like Family Member Nlrx1, Ali A. Abdul-Sater, Najwene Saïd-Sadier, Verissa M. Lam, Bhavni Singh, Matthew A. Pettengill, Fraser Soares, Ivan Tattoli, Simone Lipinski, Stephen E. Girardin, Philip Rosenstiel, David M. Ojcius

All Dugoni School of Dentistry Faculty Articles

Chlamydia trachomatis infections cause severe and irreversible damage that can lead to infertility and blindness in both males and females. Following infection of epithelial cells, Chlamydia induces production of reactive oxygen species (ROS). Unconventionally, Chlamydiae use ROS to their advantage by activating caspase-1, which contributes to chlamydial growth. NLRX1, a member of the Nod-like receptor family that translocates to the mitochondria, can augment ROS production from the mitochondria following Shigella flexneri infections. However, in general, ROS can also be produced by membrane-bound NADPH oxidases. Given the importance of ROS-induced caspase-1 activation in growth of the chlamydial vacuole, we investigated the …

Go to article

Microbial Nad Metabolism: Lessons From Comparative Genomics, Francesca Gazzaniga, Rebecca Stebbins, Sheila Z. Chang, Mark A. Mcpeek, Charles Brenner Sep 2009

Microbial Nad Metabolism: Lessons From Comparative Genomics, Francesca Gazzaniga, Rebecca Stebbins, Sheila Z. Chang, Mark A. Mcpeek, Charles Brenner

Dartmouth Scholarship

NAD is a coenzyme for redox reactions and a substrate of NAD-consuming enzymes, including ADP-ribose transferases, Sir2-related protein lysine deacetylases, and bacterial DNA ligases. Microorganisms that synthesize NAD from as few as one to as many as five of the six identified biosynthetic precursors have been identified. De novo NAD synthesis from aspartate or tryptophan is neither universal nor strictly aerobic. Salvage NAD synthesis from nicotinamide, nicotinic acid, nicotinamide riboside, and nicotinic acid riboside occurs via modules of different genes. Nicotinamide salvage genes nadV and pncA, found in distinct bacteria, appear to have spread throughout the tree of life …

Go to article

Aerobic Biodegradation Of Methyl Tert-Butyl Ether By Aquifer Bacteria From Leaking Underground Storage Tank Sites, S. R. Kane, H. R. Beller, T. C. Legler, C. J. Koester, Holly C. Pinkart, R. U. Halden, A. M. Happel Dec 2001

Aerobic Biodegradation Of Methyl Tert-Butyl Ether By Aquifer Bacteria From Leaking Underground Storage Tank Sites, S. R. Kane, H. R. Beller, T. C. Legler, C. J. Koester, Holly C. Pinkart, R. U. Halden, A. M. Happel

All Faculty Scholarship for the College of the Sciences

The potential for aerobic methyl tert-butyl ether (MTBE) degradation was investigated with microcosms containing aquifer sediment and groundwater from four MTBE-contaminated sites characterized by oxygen-limited in situ conditions. MTBE depletion was observed for sediments from two sites (e.g., 4.5 mg/liter degraded in 15 days after a 4-day lag period), whereas no consumption of MTBE was observed for sediments from the other sites after 75 days. For sediments in which MTBE was consumed, 43 to 54% of added [U-14C]MTBE was mineralized to14CO2. Molecular phylogenetic analyses of these sediments indicated the enrichment of species closely …

Go to article

Nutrient Limitation In A Southwestern Desert Reservoir: Eutrophication Of Las Vegas Bay, Lake Mead, Nevada, Davine M. Lieberman Sep 1995

Nutrient Limitation In A Southwestern Desert Reservoir: Eutrophication Of Las Vegas Bay, Lake Mead, Nevada, Davine M. Lieberman

Publications (WR)

Algal bioassay tests were conducted with Selenastrum capricornutum and natural algae on inner Las Vegas Bay, Lake Mead, Nevada, from December 1992 through September 1993, to identify any nutrient limitation in an area of the reservoir that has experienced problems associated with severe nutrient enrichment. Three areas were sampled based on a gradient of water quality conditions that existed in Las Vegas Bay (LVB). Disodium ethylenedinitrilotetraacetate (EDTA) significantly stimulated algal growth compared to non-EDTA treatment. Algal bioassays indicated that phosphorus (P) was the primary limiting nutrient at all stations for most of the test dates. Chl a response with EDTA …

Go to article

Trophic Transfer Of Fatty Acids, Sterols, And A Triterpenoid Alcohol Between Bacteria, A Ciliate, And The Copepod Acartia Tonsa, Melissa C. Ederington, George B. Mcmanus, H. Rodger Harvey Jul 1995

Trophic Transfer Of Fatty Acids, Sterols, And A Triterpenoid Alcohol Between Bacteria, A Ciliate, And The Copepod Acartia Tonsa, Melissa C. Ederington, George B. Mcmanus, H. Rodger Harvey

OES Faculty Publications

The incorporation of lipids into the copepod Acartia tonsa and its eggs was measured when it was fed either a bacterivorous ciliate (Pleuronema sp.) or a diatom (Thalassiosira weissflogii). Egg production was 10-fold higher on the diatom diet, whereas hatch success of eggs was the same for algal and ciliate diets. Adult copepods fed diatoms contained more total fatty acid and sterols than copepods fed the ciliate diet, and individual lipids reflected the dietary source. Eggs from diatom-fed copepods had fewer fatty acids but more sterols than eggs from copepods on a ciliate diet. Ciliate-fed copepods and …

Go to article

The Primary Structure Of A Fungal Chitin Deacetylase Reveals The Function For Two Bacterial Gene Products., Dimitris Kafetzopoulos, George Thireos, John N. Vournakis, Vassilis Bouriotis Sep 1993

The Primary Structure Of A Fungal Chitin Deacetylase Reveals The Function For Two Bacterial Gene Products., Dimitris Kafetzopoulos, George Thireos, John N. Vournakis, Vassilis Bouriotis

Dartmouth Scholarship

Chitin deacetylase (EC 3.5.1.41) hydrolyzes the N-acetamido groups of N-acetyl-D-glucosamine residues in chitin. A cDNA to the Mucor rouxii mRNA encoding chitin deacetylase was isolated, characterized, and sequenced. Protein sequence comparisons revealed significant similarities of the fungal chitin deacetylase to rhizobial nodB proteins and to an uncharacterized protein encoded by a Bacillus stearothermophilus open reading frame. These data suggest the functional homology of these evolutionarily distant proteins. NodB is a chitooligosaccharide deacetylase essential for the biosynthesis of the bacterial nodulation signals, termed Nod factors. The observed similarity of chitin deacetylase to the B. stearothermophilus gene product suggests that this gene …

Go to article

An Electrochemical Method Of Measuring The Oxidation Rate Of Ferrous To Ferric Iron With Oxygen In The Presence Of Thiobacillus Ferrooxidans, David J. Oliver, B. Pesic, P. Wichlacz Jan 1989

An Electrochemical Method Of Measuring The Oxidation Rate Of Ferrous To Ferric Iron With Oxygen In The Presence Of Thiobacillus Ferrooxidans, David J. Oliver, B. Pesic, P. Wichlacz

David J. Oliver

The oxidation of Fe2+ with oxygen in sulfate solutions was studied in the presence of T. ferrooxidans. To measure the chemical activity of bacteria, and the oxidation rate of iron, the redox potentials of solutions were continuously monitored during the experiments. The redox potentials were simultaneously monitored on the platinum and pyrite indicator electrodes. The redox potential versus time curves were further used to calculate the basic kinetic parameters, such as the reaction orders, the activation energy, and the frequency factor. It was found that under atmospheric conditions, and at Fe2+ < 0.001M, T < 25°C, and at pH above 2.2, the oxidation of iron is governed by the following rate expression: [equation image] Below pH = 2.2, the oxidation rate is independent of H+ Concentration.

Go to article

Next Last