Microbiology Commons^™

Solid Cystic Papillary Epithelial Neoplasm Of Pancreas: A Series Of Three Cases With Review Of Literature, Z Ahmed, N Yaqoob, S Muzaffar, N Kayani, R Minhas

Department of Pathology and Laboratory Medicine

No abstract provided.

Enhanced Production Of Farnesol By Candida Albicans Treated With Four Azoles, Jacob M. Hornby, Kenneth Nickerson

Papers in Microbiology

The dimorphic fungus Candida albicans excretes farnesol, which is produced enzymatically from the sterol biosynthetic intermediate farnesyl pyrophosphate. Inhibition of C. albicans by four azole antifungals, fluconazole, ketoconazole, miconazole, and clotrimazole, caused elevated farnesol production (10- to 45-fold). Furthermore, farnesol production occurs in both laboratory strains and clinical isolates (J. M. Hornby et al., Appl. Environ. Microbiol. 67:2982-2992, 2001) of C. albicans.

Mechanisms Of Oxidative Stress Resistance In Porphyromonas Gingivalis W83, Neal Antonio Johnson

Loma Linda University Electronic Theses, Dissertations & Projects

Porphyromonas gingivalisis one of the most important bacterial etiological agents involved in adult periodontitis. It possesses several virulence factors which aid in its persistence in the periodontal pocket leading to the development of some systemic illnesses. As an anaerobe, P. gingivalismust employ mechanisms to avoid oxidative stress generated by reactive oxygen species during phagocytosis, or the occasional exposure to air. Presently, only three proteins with antioxidant enzymatic function have been identified as playing a role in oxidative stress resistance in P. gingivalis. In this study, attention was focused on the alkyl hydroperoxidase subunit C (ahpC)and bacterioferritin comigratory …

Distribution Of Kaposi Sarcoma–Associated Herpesvirus/Human Herpesvirus 8 In Maternal Saliva And Breast Milk In Zambia: Implications For Transmission, Brad P. Brayfield, Chipepo Kankasa, John T. West, Jubra Muyanga, Ganapati Bhat, Winslow Klaskala, Charles D. Mitchell, Charles Wood

Nebraska Center for Virology: Faculty Publications

Background. The seroprevalence of Kaposi sarcoma–associated herpesvirus (KSHV)/human herpesvirus 8 (HHV-8) in sub-Saharan Africa suggests that multiple routes of transmission exist. In the present study,we examined 2 possible routes of mother-to-child transmission, through breast milk and saliva, during the first 6 months after delivery. Methods. The prevalence of HHV-8 DNA in the breast-milk cells (n=75), milk supernatant (n=56), colostrum (n=2), and saliva cells (n=65) of HHV-8–seropositive mothers who recently gave birth was examined. Polymerase chain reaction analysis was performed for the detection of HHV-8 in cross-sectional samples isolated at 2, 4, and 6 months after delivery.

Results. None of the …

Cd4 T Cell Responses To Influenza Infection, Deborah M. Brown, Eulogia Roman, Susan L. Swain

Nebraska Center for Virology: Faculty Publications

Immune responses to viral infections involve a complex orchestration between innate signals and adaptive responses of specific T and B cells. Anti-viral CD4 cells can direct CD8 responses by secreting a Type 1 panel of cytokines including IFN-γ, IL-2 and TNF- α and can drive B cell production of IgG2a to neutralize infective viral particles. This review will focus specifically on the role of CD4 cells in the immune response to influenza, an acute, localized respiratory viral infection. We suggest that CD4 cells act as direct effectors in protection against influenza, may contribute to immunopathology and generate functionally distinct memory …

Evaluation Of Frequency Of Isolation And Trends In Antibiotic Resistance Among Campylobacter Isolates Over 11 Year Period, N G. Ibrahim, Afia Zafar, Rumina Hasan

Department of Pathology and Laboratory Medicine

Objective:
To analyze frequency of isolation and trends in antibiotic resistance among Campylobacter isolates over 11 year period in Microbiology Laboratory, Aga Khan University from the year 1992-2002.
Methods:
Total 52,777 stool specimens were processed during the study period. Enteric pathogens isolated from 8,483 stool samples were further analyzed for frequency of isolation and antimicrobial resistance. Statistical Analysis was done by using descriptive statistics of SPSS version 10. Values were expressed as percentages, mean and rates.
Results:
Campylobacter species were third in frequency of isolation with an isolation rate of 24.8%. C. jejuni was the predominant pathogen followed by C.coli. …

Mucormycosis Complicating Interstitial Nephritis--Two Cases And Brief Literature Review, A Malik, A Soofi, A Ahmad, N Kayani

Department of Pathology and Laboratory Medicine

No abstract provided.

Multiple Signal Transducers And Activators Of Transcription Are Induced By Ebv Lmp-1, Luwen Zhang, Ke Hong, Jun Zhang, Joseph S. Pagano

Nebraska Center for Virology: Faculty Publications

Epstein-Barr virus (EBV) latent membrane protein 1 (LMP-1) is required for EBV immortalization of primary B cells in vitro. Signal transducers and activators of transcription (STATs) play a pivotal role in the initiation and maintenance of certain cancers. STAT proteins, especially STAT-1, -3, and -5, are persistently tyrosine phosphorylated or activated in many cancers. We show here that EBV-infected type III latency cells, in which the EBV oncoprotein, LMP-1 is expressed, express high levels of four STATs (STAT-1, -2, -3, and -5A) and that LMP-1 is responsible for the induction of three (STAT-1, -2, and -3). In addition, the C-terminal …

Pcr And 16s Rdna Sequencing For Identifying And Comparing Gram-Negative Bacteria, Molly Truax

Honors Capstones

Capstone submitted as a graduation requirement for the BSU Honors Program.

Caenorhabditis Elegans: A Look At Koch's Postulates And Host-Pathogen Interactions, Nicole Helmrichs

Honors Capstones

Capstone submitted as a graduation requirement for the BSU Honors Program.

Methods For Detection Of Salmonella Spp., Parichaya Attaphongse

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Worldwide concern about food safety and associated health costs is increasing, and Salmonella contamination of foods is one of the most important causes of foodborne disease outbreaks. Although conventional detection methods for Salmonella offer high sensitivity and low cost, they require many different steps and are very time consuming. Ideally, methods to detect Salmonella in foods should be rapid, provide high specificity and sensitivity, be cost-effective, and low labor-intensive. Many rapid tests have been developed to address these goals, including DNA-based tests such as nucleic acid hybridization and PCR, immunoassay-based tests such as ELISA, ELF A and immunomagnetic method, and …

Rapid Detection Of Salmonella Without Enrichment, Emily J. Harrington

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Salmonella is one of the leading foodborne pathogens causing illness today. Because of this, Salmonella rapid detection methods are under immense study for use in food. The traditional method, using the Food and Drug Administration- approved Bacterial Analytical Manual procedure, takes 4-6 days for Salmonella detection in food. Other rapid methods still take at least 16 h for detection due to their enrichment steps.

The hypothesis of this study was that the use of immobilized antibodies coupled with polymerase chain reaction (PCR) can be used for the rapid capture and detection of Salmonella spp. in food without the need for …

Mammary Echinococcosis: Two Cases And Literature Review, N Yaqoob, N Kayani, M S. Shamim

Department of Pathology and Laboratory Medicine

No abstract provided.

Isolation And Characterization Of A Generalized Transducing Phage For Pseudomonas Aeruginosa Strains Pao1 And Pa14, Jonathan M. Budzik, William A. Rosche, Arne Rietsch, George A. O'Toole

Dartmouth Scholarship

A temperate, type IV pilus-dependent, double-stranded DNA bacteriophage named DMS3 was isolated from a clinical strain of Pseudomonas aeruginosa. A clear-plaque variant of this bacteriophage was isolated. DMS3 is capable of mediating generalized transduction within and between P. aeruginosa strains PA14 and PAO1, thus providing a useful tool for the genetic analysis of P. aeruginosa.

Development And Characterization Of Eukaryotic Biomimetic Liposomes, Bradley Jay Taylor

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study developed and characterized phospholipid vesicles, or liposomes, that mimic cell surfaces. Microemulsified liposomes contained biotinylated phosphatidylethanolamine, allowing them to be immobilized to avidin-coated glass. Laminin (LN), glycosphingolipids (GMl and GM3), and Escherichia coli's mechanosensitive channel of large conductance (EcoMscL) were embedded into liposome membranes. It was determined whether these embedded molecules exhibited their physiological roles of adhesion, cell recognition, and mechanosensation, respectively. Confocal laser scanning microscopy (CLSM) was employed to examine the interaction of fluorescently probed proteins, toxins, and bacteria with the immobilized microemulsified liposomes. Capture of individual and simultaneous multiple species of bacteria by GMl, GM3, …

Hormone Mediated Transport Of Calcium And Phosphate In Polarized Epithelial Cells, Tremaine M. Sterling

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of 1,25(OH)₂D₃, PTH and 25(OH)D₃ on phosphate or calcium uptake were studied in cultured, adherent chick enterocytes over a period of 10 min after hormone addition. Time course studies of cells treated with 130 pM 1,25(OH)₂D₃ showed an increase in ³²P uptake as early as 3 min. Similar studies with 65 pM bPTH(l1-34) resulted in an increase in ⁴⁵Ca uptake only if the cells had been cultured in serum. (OH)D₃, which is not firmly established as an active metabolite of vitamin D, was shown to increase …

Methanogenic Archaea And Human Periodontal Disease, Paul W. Lepp, Mary M. Brinig, Cleber C. Ouverney, Katherine Palm, Gary C. Armitage, David A. Relman

Faculty Publications, Biological Sciences

Archaea have been isolated from the human colon, vagina, and oral cavity, but have not been established as causes of human disease. In this study, we reveal a relationship between the severity of periodontal disease and the relative abundance of archaeal small subunit ribosomal RNA genes (SSU rDNA) in the subgingival crevice by using quantitative PCR. Furthermore, the relative abundance of archaeal small subunit rDNA decreased at treated sites in association with clinical improvement. Archaea were harbored by 36% of periodontitis patients and were restricted to subgingival sites with periodontal disease. The presence of archaeal cells at these sites was …

Physiology Of The Thermophilic Acetogen Moorella Thermoacetica, Harold L. Drake, Steven L. Daniel

Faculty Research & Creative Activity

Moorella thermoacetica (originally isolated as Clostridium thermoaceticum) has served as the primary acetogenic bacterium for the resolution of the acetyl coenzyme A (acetyl-CoA) orWood–Ljungdahl pathway, a metabolic pathway that (i) autotrophically assimilates CO2 and (ii) is centrally important to the turnover of carbon in many habitats. The purpose of this article is to highlight the diverse physiological features of this model acetogen and to examine some of the consequences of its metabolic capabilities.

Physiology Of The Thermophilic Acetogen Moorella Thermoacetica, Harold Drake, Steven Daniel

Faculty Research & Creative Activity

Moorella thermoacetica (originally isolated as Clostridium thermoaceticum) has served as the primary acetogenic bacterium for the resolution of the acetyl coenzyme A (acetyl-CoA) orWood–Ljungdahl pathway, a metabolic pathway that (i) autotrophically assimilates CO2 and (ii) is centrally important to the turnover of carbon in many habitats. The purpose of this article is to highlight the diverse physiological features of this model acetogen and to examine some of the consequences of its metabolic capabilities.

Fabrication, Characterization, And Chemical Sensing Of Silicon Dioxide Microcantilevers, Yanjun Tang

Doctoral Dissertations

The objective of this work is to design and fabricate an advanced silicon dioxide microcantilever sensor and to investigate chemical and biological sensing by microtechnology.

Microcantilever sensor technology has many advantages including fast response time, lower cost of fabrication, the possibility of sensor arrays with small overall dimensions, the ability to explore microenvironments, and improved portability for field applications. For all of these advantages, microcantilever chemical and biological sensors have drawn more and more attention.

So far, all other microcantilevers were designed and fabricated for AFM applications. We developed a novel SiO2 microcantilever especially for chemical and biological sensor applications. …

Drosophila As An Emerging Model To Study Metastasis, Madhuri Kango-Singh, Georg Halder

Biology Faculty Publications

Metastasis is the primary cause of human cancer-related deaths. Two recent studies describe a system for testing how multiple genetic events synergize to promote neoplastic growth and metastasis in Drosophila, paving the way for systematic approaches to understanding metastasis using the powerful tools of Drosophila genetics.

A Dominant-Negative Fur Mutation In Bradyrhizobium Japonicum, Heather P. Benson, Kristin Levier, Mary Lou Guerinot

Dartmouth Scholarship

In many bacteria, the ferric uptake regulator (Fur) protein plays a central role in the regulation of iron uptake genes. Because iron figures prominently in the agriculturally important symbiosis between soybean and its nitrogen-fixing endosymbiont Bradyrhizobium japonicum, we wanted to assess the role of Fur in the interaction. We identified a fur mutant by selecting for manganese resistance. Manganese interacts with the Fur protein and represses iron uptake genes. In the presence of high levels of manganese, bacteria with a wild-type copy of the furgene repress iron uptake systems and starve for iron, whereas fur mutants fail to …

Inoculum Size Effect In Dimorphic Fungi: Extracellular Control Of Yeast-Mycelium Dimorphism In Ceratocystis Ulmi, Jacob M. Hornby, Sarah M. Jacobitz-Kizzier, Donna J. Mcneel, Ellen C. Jensen, David S. Treves, Kenneth W. Nickerson

Papers in Microbiology

We studied the inoculum size effect in Ceratocystis ulmi, the dimorphic fungus that causes Dutch elm disease. In a defined glucose-proline-salts medium, cells develop as budding yeasts when inoculated at >106 spores per ml and as mycelia when inoculated at type, age of the spores, temperature, pH, oxygen availability, trace metals, sulfur source, phosphorous source, or the concentration of glucose or proline. Similarly, it was not influenced by added adenosine, reducing agents, methyl donors, amino sugars, fatty acids, or carbon dioxide. Instead, growing cells excreted an unknown quorum-sensing factor that caused a morphological shift from mycelia to budding yeasts. …

Detection Of Bacteria To Dental Tissue By Low-Light Imaging, G-Hong Robert Hsu

Loma Linda University Electronic Theses, Dissertations & Projects

Bacteria have been shown to play an important role in the development of pulp and periradicular disease. The source of the infective bacteria is most often the oral cavity. Previous studies have detected bacteria in teeth that are structurally intact that seemingly have no communication intraorally. Anachoresis has been proposed as a mechanism for localizing circulating bacteria to such teeth. In several previous bacteriologic anachoresis studies, bacteria have been found to localize in inflamed dental tissues. The criticism most commonly associated with these investigations has been the potential contribution of contaminant bacteria resulting in false positive findings.

Low-light image analysis …

The Biological Burden Of Antibiotic Resistance In Staphylococcus Aureus, Natasha Samantha Dean

Loma Linda University Electronic Theses, Dissertations & Projects

Antibiotic resistance is a major problem. Resistance is often mediated by genes on bacterial plasmids and dissemination of resistance is commonly achieved by plasmid transfer. The mechanisms of resistance that are presently understood suggest that resistance is energetically costly. If this is generally true, resistance would reduce the fitness of cells in the absence of antibiotics. We examined the hypothesis that resistance reduces the fitness of microorganism and requires continuous selection to be maintained. To test this hypothesis, we measured the effects of plasmid-borne resistance genes on cell growth by comparing the growth rates of Staphylococcus aureus with and without …

Oxalate Metabolism By The Acetogenic Bacterium Moorella Thermoacetica, Steven L. Daniel, Christine Pilsl, Harold L. Drake

Faculty Research & Creative Activity

Whole-cell and cell-extract experiments were performed to study the mechanism of oxalate metabolism in the acetogenic bacterium Moorella thermoacetica. In short-term, whole-cell assays, oxalate consumption was low unless cell suspensions were supplemented with CO2, KNO3, or Na2S2O3. Cell extracts catalyzed the oxalate-dependent reduction of benzyl viologen. Oxalate consumption occurred concomitant to benzyl viologen reduction; when benzyl viologen was omitted, oxalate was not appreciably consumed. Based on benzyl viologen reduction, specific activities of extracts averaged 0.6 μmol oxalate oxidized min−1 mg protein−1. Extracts also catalyzed the formate-dependent reduction of NADP+; however, oxalate-dependent reduction of NADP+ was negligible. Oxalate- or formate-dependent reduction …

Oxalate Metabolism By The Acetogenic Bacterium Moorella Thermoacetica, Steven Daniel, Christine Pilsl, Harold Drake

Faculty Research & Creative Activity

Whole-cell and cell-extract experiments were performed to study the mechanism of oxalate metabolism in the acetogenic bacterium Moorella thermoacetica. In short-term, whole-cell assays, oxalate consumption was low unless cell suspensions were supplemented with CO2, KNO3, or Na2S2O3. Cell extracts catalyzed the oxalate-dependent reduction of benzyl viologen. Oxalate consumption occurred concomitant to benzyl viologen reduction; when benzyl viologen was omitted, oxalate was not appreciably consumed. Based on benzyl viologen reduction, specific activities of extracts averaged 0.6 μmol oxalate oxidized min−1 mg protein−1. Extracts also catalyzed the formate-dependent reduction of NADP+; however, oxalate-dependent reduction of NADP+ was negligible. Oxalate- or formate-dependent reduction …

Ethiopian Soils Harbor Natural Populations Of Rhizobia That Form Symbioses With Common Bean (Phaseolus Vulgaris L.), Serawit Kassa, Desta Beyene, Franklin Ampy, Amha Asseffa, Tadesse Gebremedhin, Peter Van Berkum

Department of Biology Faculty Publications

The diversity and taxonomic relationships of 83 bean-nodulating rhizobia indigenous to Ethiopian soils were characterized by PCR-RFLP of the internally transcribed spacer (ITS) region between the 16S and 23S rRNA genes, 16S rRNA gene sequence analysis, multilocus enzyme electrophoresis (MLEE), and amplified fragment-length polymorphism. The isolates fell into 13 distinct genotypes according to PCR-RFLP analysis of the ITS region. Based on MLEE, the majority of these genotypes (70%) was genetically related to the type strain of Rhizobium leguminosarum. However, from analysis of their 16S rRNA genes, the majority was placed with Rhizobium etli. Transfer and recombination of the 16S rRNA …

Phylogenetic Analyses Of Texas Isolates Indicate An Evolving Subtype Of The Clade B Feline Immunodeficiency Viruses, Eric A. Weaver, Ellen W. Collisson, Margaret Slater, Guan Zhu

Nebraska Center for Virology: Faculty Publications

Rigorous phylogenetic analyses were used to compare the nucleotide sequences of feline immunodeficiency virus strains isolated from Texas and throughout the world. The envelope V3-V4 sequences and capsid gene of the Texas isolates formed a cluster between subtypes B and E. Statistical comparisons with other published sequences confirmed that the Texas group is a unique cluster, possibly a new subtype, arising from subtype B.

Feline immunodeficiency virus (FIV) was initially isolated in 1987 from a cat in California with severe immunodeficiency and has been recognized as a common worldwide feline pathogen (11, 14, 19, 20, 33). FIV-infected cats exhibit a …

Q-Probes Study Of Replicate Specimens At The Clinical Laboratory, The Aga Khan University Hospital, Karachi, L Ali, I Siddiqui

Department of Pathology and Laboratory Medicine

Objective: The aim of this Q-probes study was to evaluate the precision of replicate specimens.Methods: This Q-probes study done at the Clinical Laboratory, The Aga Khan University Hospital Karachi is about routine chemistry analytes because of their importance in critical care patients. The analytes data was collected for six months from April to September 2002. There were total 358 samples, which were given for reanalysis during this period under the constant working conditions. After analysis, results of both the runs on different days, were compared to determine the percent difference between the results. After calculating the percent difference, the results …