Life Sciences Commons^™

Microbial Biofilms: From Ecology To Molecular Genetics, Mary Ellen Davey, George A. O'Toole

Dartmouth Scholarship

Biofilms are complex communities of microorganisms attached to surfaces or associated with interfaces. Despite the focus of modern microbiology research on pure culture, planktonic (free-swimming) bacteria, it is now widely recognized that most bacteria found in natural, clinical, and industrial settings persist in association with surfaces. Furthermore, these microbial communities are often composed of multiple species that interact with each other and their environment. The determination of biofilm architecture, particularly the spatial arrangement of microcolonies (clusters of cells) relative to one another, has profound implications for the function of these complex communities. Numerous new experimental approaches and methodologies have been …

Influence Of Infected Cell Growth State On Bacteriophage Reactivation Levels, Dana R. Kadavy, Julie J. Shaffer, Susan E. Lott, Thomas A. Wolf, Cathy E. Bolton, William H. Gallimore, Eugene L. Martin, Kenneth W. Nickerson, Tyler A. Kokjohn

Papers in Microbiology

Reactivation of UV-C-inactivated Pseudomonas aeruginosa bacteriophages D3C3, F116, G101, and UNL-1 was quantified in host cells infected during the exponential phase, during the stationary phase, and after starvation (1 day, 1 and 5 weeks) under conditions designed to detect dark repair and photoreactivation. Our experiments revealed that while the photoreactivation capacity of stationary-phase or starved cells remained about the same as that of exponential-phase cells, in some cases their capacity to support dark repair of UV-inactivated bacteriophages increased over 10-fold. This enhanced reactivation capacity was correlated with the ca. 30- fold-greater UV-C resistance of P. aeruginosa host cells that were …

Characterization Of Transcripts Expressed From Human Herpesvirus 6a Strain Gs Immediate-Early Region B U16-U17 Open Reading Frames, Linda Flebbe-Rehwaldt, Charles Wood, Bala Chandran

Nebraska Center for Virology: Faculty Publications

Several gene fragments of human herpesvirus 6 (HHV-6) have been shown to activate the human immunodeficiency virus (HIV) type 1 long terminal repeat (LTR). An open reading frame (ORF) designated B701 (Y. Geng, B. Chandran, S. F. Josephs, and C. Wood, J. Virol. 66:1564–1570, 1992), found within a 22-kb HHV-6A strain GS [HHV-6A(GS)] genomic fragment and a 3.8-kb SalI subfragment, was shown to activate the HIV LTR. B701, also known as HHV-6 U16, is located in the immediate-early B (IE-B) region of the genome. The sequence of the 3.8-kb genomic fragment of HHV-6A(GS) is nearly identical to the published …

Granular Cell Tumor Of The Breast: An Uncommon Lesion That Mimics Carcinoma, S Muzafar, M S. Siddiqui, Naila Kayani, I K. Lodhi, Sheema H. Hasan

Department of Pathology and Laboratory Medicine

No abstract provided.

Histological Pattern Of Ovarian Neoplasma., Zubair Ahmad, Naila Kayani, Sheema H. Hasan, Suhail Muzaffar, Muhammad Shafiq Gill

Department of Pathology and Laboratory Medicine

Abstract

Objective: To see the morphological pattern of benign and malignant ovarian neoplasms. Method: Retrospective study of all consecutive cases of ovarian neoplasms diagnosed at Aga Khan University Hospital between 1st January 1993 and 30th September 1998. Setting: The Section of Histopathology, AKUH, Karachi. Observation: Of 855 ovarian tumours 506 (59.18%) were benign and 349(40.81%) malignant. Surface epithelial - stromal tumours comprised 63.50% of all tumours. Benign cystic teratoma was the commonest benign tumour (35.17% of all benign tumours) and serous cystadenocarcinoma was the commonest malignant tumour (33.33% of all malignant tumours). Mucinous cystadenocarcinomas are more common in our population …

Natural Antibiotic Resistance Of Bacteria Isolated From Larvae Of The Oil Fly, Helaeomyia Petrolei, Dana R. Kadavy, Jacob M. Hornby, Terry Haverkost, Kenneth W. Nickerson

Papers in Microbiology

Helaeomyia petrolei (oil fly) larvae inhabit the asphalt seeps of Rancho La Brea in Los Angeles, Calif. The culturable microbial gut contents of larvae collected from the viscous oil were recently examined, and the majority (9 of 14) of the strains were identified as Providencia spp. Subsequently, 12 of the bacterial strains isolated were tested for their resistance or sensitivity to 23 commonly used antibiotics. All nine strains classified as Providencia rettgeri exhibited dramatic resistance to tetracycline, vancomycin, bacitracin, erythromycin, novobiocin, polymyxin, colistin, and nitrofurantoin. Eight of nine Providencia strains showed resistance to spectinomycin, six of nine showed resistance to …

Mortality Of Escherichia Coli O157:H7 In Two Soils With Different Physical And Chemical Properties, D. N. Mubiru, Mark S. Coyne, John H. Grove

Plant and Soil Sciences Faculty Publications

Wild and domesticated animals can harbor a pathogenic Escherichia coli strain designated as O157:H7. Potential health problems could occur if strain O157:H7 is a more robust survivor in defecated waste than commonly used indicator bacteria. A laboratory study was conducted to assess E. coli O157:H7 survival relative to a nonpathogenie E. coli strain in two soils with different physical and chemical characteristics. Bacteria in the inoculated soils were enumerated on a weekly basis for 8 wk using a most probable number (MPN) technique. First-order decay models were used to describe bacteria mortality in the soils. Decay series were described slightly …

Marine Planktonic Archaea Take Up Amino Acids, Cleber C. Ouverney, Jed A. Fuhrman

Faculty Publications, Biological Sciences

Archaea are traditionally thought of as “extremophiles,” but recent studies have shown that marine planktonic Archaea make up a surprisingly large percentage of ocean midwater microbial communities, up to 60% of the total prokaryotes. However, the basic physiology and contribution of Archaea to community microbial activity remain unknown. We have studied Archaea from 200-m depths of the northwest Mediterranean Sea and the Pacific Ocean near California, measuring the archaeal activity under simulated natural conditions (8 to 17°C, dark and anaerobic) by means of a method called substrate tracking autoradiography fluorescence in situ hybridization (STARFISH) that simultaneously detects specific cell types …

Porcine Reproductive And Respiratory Syndrome Virus: Description Of Persistence In Individual Pigs Upon Experimental Infection, R. Allende, W. W. Laegreid, G. F. Kutish, J. A. Galeota, R. W. Wills, Fernando A. Osorio

Nebraska Center for Virology: Faculty Publications

We studied the persistence of porcine reproductive and respiratory syndrome virus (PRRSV) in individual experimentally infected pigs, during a period of up to 150 days postinfection (dpi). The results of this study suggest that the persistence of PRRSV involves continuous viral replication but that it is not a true steady-state persistent infection. The virus eventually clears the body and seems to do it in most of the animals by 150 dpi or shortly thereafter. High genetic stability was seen for several regions of the persistent PRRSV’s genome, although some consistent mutations in the genes of envelope glycoproteins and M protein …

Changing Pattern Of Antimicrobial Susceptibility Of Organisms Causing Community Acquired Urinary Tract Infections, B J. Farooqi, F Shareeq, Q K. Rizvi, H S. Qureshi, M K. Ashfaq

Department of Pathology and Laboratory Medicine

Objective:
To assess common organisms causing Urinary Treat Infection (UTI) in this community and to see antimicrobial susceptibility pattern of these isolates.
Design:
Prospective study on urine samples.
Setting: Tertiary care hospital in Karachi.Methods: Over a period of 8 years (1990-97) 9,892 urine samples grew significant bacteriuria for various organisms. All Gram negative rods and entercocci was identified by using API 20E and API 32 strips respectively. Staphylococci were identified by catalase, coagulase and D'Nase tests. Antimicrobial sensitivity testing of all isolates was performed on Diagnostic Sensitivity Test plates by Kerby Bauer method. The discs used were ampicillin, trimethoprim-sulfamethoxazole, cefotaxime, …

Changes In Bacterioplankton Metabolic Capabilities Along A Salinity Gradient In The York River Estuary, Virginia, Usa, G. E. Schultz, H. W. Ducklow

VIMS Articles

Changes in metabolic capabilities of bacterial communities along the estuarine salinity gradient may affect the extent of organic matter processing and bacterial growth and accumulation during transit through the system; As part of a larger study of estuarine microbial processes, we attempted to quantify differences in bacterial community structure using Biolog plates. Biolog GN plates (Biolog, Inc., Hayward, CA, USA) were used to determine differences in bacterioplankton community metabolic potential. Biolog GN microplates are 96-well microtiter plates in which each well contains an individual carbon source as well the redox dye tetrazolium violet. As bacteria grow and oxidize each substrate, …

A Receptor-Like Glycoprotein From Dictyostelium Discoideum: Functions In Phagocytosis And Cell Adhesion?, P. Christopher Larosa, Melissa B. Meirer, Catherine P. Chia

Papers in Microbiology

The molecular mechanisms for the initial recognition and subsequent internalization of food and unicellular pathogens by phagocytes are incompletely understood We have hypothesized that a surface-exposed, glycosylated I30 kDa protein, gp130, that 1s concentrated on the plasma membrane and found In phagosomes, has a role In phagocytosis by D. discoideum amoebae. GpI30 appears to have a cytoskeletal association and has extracellular domains susceptible to proteolytic digestion. It is tightly bound to the plasma membrane probably via a carboxyterminal hydrophobic anchor predicted from the cDNA. Gp130 may be the same as a similarly sized protein, gp126, that was implicated as a …

A Role For Calcineurin In Dictyostelium Discoideum Phagocytosis, Aidong Yuan, Catherine P. Chia

Papers in Microbiology

The Ca2+/calmodul1n-dependent protein phosphatase calcinewin is involved in the development of the cellular slime mold Dictyostelium discoideum. Because of its interactions with Ca2+, which appear to influence D. discoideum phagocytosis (Yuan and Chia, 1999, Mol. Biol. Cell 10, 220a), we undertook studies to test whether calcineurin also plays a role in Dictyostelium phagocytosis. The immunosuppressants cyclosporin A and FK506, through the formation of cyclosporin A-cyclophilin A and FK506- FK506-binding protein complexes, respectively, inhibited calcineurin activity. These two calcineurin inhibitors suppressed phagocytosis of fluorescently labeled yeast in a dose-dependent manner. Although it inhib~ted phagocytosis, cyclosporin A had an insignificant effect …

Integrity Of The Actin Cytoskeleton Required For Both Phagocytosis And Macropinocytosis In Dictyostelium Discoideum, Aidong Yuan, Catherine P. Chia

Papers in Microbiology

Filamentous (F-) actin is enriched in cellular extensions, such as phagocytic cups and macropioocytic crowns, of Dlctyostelium discoideum amebae. Previous studies of actin-disrupting agents that implicated the involvement of the actin cytoskeleton in Dictyostelium phagocytosis and pinocytosis, however, have yielded conflicting results. We show that the integrity of the actin cytoskeleton is required for both phagocytosis and macropinocytosis in D. discoideum with latrunculin A (IatA), which binds to monomeric actin, and cytochalasin A (cytA), which caps the plus end of actin filaments. Using rhodamine-phalloidin to visualize F-actin, cells treated for 30 min. with 1 to 4 pM of latA displayed …

Genetic Diversity Of Beta-Thalassemia Mutations In Pakistani Population, B Khateeb, T Moatter, A M. Shaghil, S Haroon, G N. Kakepoto

Department of Pathology and Laboratory Medicine

Background:
beta-thalassemia is one of the most common inherited single gene disorder in Pakistan. It is characterized by reduced or absent beta-globin gene expression resulting in abnormal maturation and survival of red blood cells. Due to high prevalence of this disease in the local population, it has become important for the health care providers to encourage people to utilize laboratory facilities for carrier and prenatal genetic testing.
Objective:
To study the frequency of beta-thalassemia mutations in Pakistani population.
Setting:
A tertiary care teaching hospital.
Methods:
Blood samples of 72 couples and chorionic villus (CV) biopsy specimen collected at the Aga …

Nutrient Absorption And Utilization By Wing And Flight Muscle Morphs Of The Cricket Gryllus Firmus: Implications For The Trade-Off Between Flight Capability And Early Reproduction, Anthony J. Zera, Tammy Brink

Anthony Zera Publications

Absorption efficiency (AD, approximate digestibility, assimilation efficiency) of various macronutrients and conversion of absorbed nutrients to biomass (ECD) were compared among the two types of flightless morph and the flight-capable morph of the cricket, Gryllus firmus. No biologically significant phenotypic or genetic difference in AD for carbohydrate, protein or lipid was observed among morphs fed either a high-nutrient (100%) or a low-nutrient (25%) diet. Thus, previously-documented differences among adult morphs in carbohydrate and lipid content must be caused by processes other than variation in nutrient absorption by morphs during adulthood. Relative absorption efficiency of total dry mass of food …

Vibrio Cholerae H-Ns Silences Virulence Gene Expression At Multiple Steps In The Toxr Regulatory Cascade, Melinda B. Nye, James D. Pfau, Karen Skorupski, Ronald K. Taylor

Dartmouth Scholarship

H-NS is an abundant nucleoid-associated protein involved in the maintenance of chromosomal architecture in bacteria. H-NS also has a role in silencing the expression of a variety of environmentally regulated genes during growth under nonpermissive conditions. In this study we demonstrate a role for H-NS in the negative modulation of expression of several genes within the ToxR virulence regulon ofVibrio cholerae. Deletion of hns resulted in high, nearly constitutive levels of expression of the genes encoding cholera toxin, toxin-coregulated pilus, and the ToxT virulence gene regulatory protein. For the cholera toxin- and ToxT-encoding genes, elevated expression in an …

Cloning Of The Bovine Immunodeficiency Virus Gag Gene And Development Of A Recombinant-Protein-Based Enzyme-Linked Immunosorbent Assay, Ling Zheng, Michelle Swanson, Jinghua Liao, Charles Wood, Sanjay Kapil, Ron Snider, Thomas A. Loughin, Harish Minocha

Nebraska Center for Virology: Faculty Publications

An enzyme-linked immunosorbent assay (ELISA) was established for the rapid detection of specific bovine immunodeficiency virus (BIV) antibodies in cattle, using recombinant Gag protein as an antigen. The gag coding region from BIV was cloned into an expression vector, pQE32, which expressed high levels of recombinant protein from Escherichia coli. The ELISA was standardized by a checkerboard titration against known BIV-positive and -negative sera from cattle and a monoclonal antibody to the Gag protein. A total of 139 cattle serum samples, from the diagnostic laboratory at Kansas State University, Manhattan, and from the Dairy Station, Louisiana State University, Baton …

Tubulin And Neurofilament Proteins Are Transported Differently In Axons Of Chicken Motoneurons, Aidong Yuan, Roland G. Mills, Catherine P. Chia, John J. Bray

Papers in Microbiology

1. We previously showed that actin is transported in an unassembled form with its associated proteins actin depolymerizing factor, cofilin, and profilin. Here we examine the specific activities of radioactively labeled tubulin and neurofilament proteins in subcellular fractions of the chicken sciatic nerve following injection of L-[35S]methionine into the lumbar spinal cord. 2. At intervals of 12 and 20 days after injection, nerves were cut into 1-cm segments and separated into Triton X-100-soluble and particulate fractions. Analysis of the fractions by high-resolution two-dimensional gel electrophoresis, immunoblotting, fluorography, and computer densitometry showed that tubulin was transported as a unimodal wave at …

Inactivation Of Lmpa, Encoding A Limpii-Related Endosomal Protein, Suppresses The Internalization And Endosomal Trafficking Defects In Profilin-Null Mutants, Lesly A. Temesvari, Linyi Zhang, Brent Fodera, Klaus-Peter Janssen, Michael Schleicher, James A. Caradelli

Publications

Profilin is a key phosphoinositide and actin-binding protein connecting and coordinating changes in signal transduction pathways with alterations in the actin cytoskeleton. Using biochemical assays and microscopic approaches, we demonstrate that profilin-null cells are defective in macropinocytosis, fluid phase efflux, and secretion of lysosomal enzymes but are unexpectedly more efficient in phagocytosis than wild-type cells. Disruption of the lmpA gene encoding a protein (DdLIMP) belonging to the CD36/LIMPII family suppressed, to different degrees, most of the profilin-minus defects, including the increase in F-actin, but did not rescue the secretion defect. Immunofluorescence microscopy indicated that DdLIMP, which is also capable of …

The Occurrence Of The Freshwater Clams, Musculium Partumeium (Say) And Pisidium Casertanum (Poli) (Bivalvia: Sphaeriidae), In The Hawaiian Islands, Albert J. Burky, Carl M. Way, Skippy Hau, M. Eric Benbow

Biology Faculty Publications

Sphaeriid clams were collected from an ancient, continuously cultivated taro pond complex at Ke‘anae Peninsula, Maui. Both species are known for adaptations for temporary pond habitats and could have been initially introduced by the earliest Hawaiian settlers transported with moist taro root stock from other areas of Oceania.

Adaptation And Selection Of Prion Protein Strain Conformations Following Interspecies Transmission Of Transmissible Mink Encephalopathy, Jason C. Bartz, Richard Bessen, Debbie Mckenzie, Richard F. Marsh, Judd M. Aiken

Nebraska Center for Virology: Faculty Publications

Interspecies transmission of the transmissible spongiform encephalopathies (TSEs), or prion diseases, can result in the adaptation and selection of TSE strains with an expanded host range and increased virulence such as in the case of bovine spongiform encephalopathy and variant Creutzfeldt-Jakob disease. To investigate TSE strain adaptation, we serially passaged a biological clone of transmissible mink encephalopathy (TME) into Syrian golden hamsters and examined the selection of distinct strain phenotypes and conformations of the disease-specific isoform of the prion protein (PrP^Sc). The long-incubation-period drowsy (DY) TME strain was the predominate strain, based on the presence of its strain-specific …

Association Of Epstein Barr Virus (Ebv) With Nasopharyngeal Carcinoma (Npc), S H. Shah, I N. Soomro, S Haroon, T Moatter

Department of Pathology and Laboratory Medicine

Aim:
To observe the frequency of nasopharyngeal carcinoma (NPC) and its association with Epstein Barr Virus (EBV) infection.
Setting:
This study included consecutive cases of nasopharyngeal carcinoma, which were diagnosed in the Department of Pathology at the Aga Khan University Hospital, Karachi in the period of two years (1996-97).
Methods:
These tumors were initially evaluated on H&E stained sections. The tumors showing evidence of keratinization were excluded from the study. The Epstein Barr Virus was detected with the help of Polymerase chain reaction in formalin fixed, paraffin embedded tissue sections.
Results:
During the study period, seventeen cases of nasopharyngeal carcinoma …

Breast Diseases In Males--A Morphological Review Of 150 Cases, M S. Gill, N Kayani, M N. Khan, S H. Hasan

Department of Pathology and Laboratory Medicine

Objective:
This study was carried out to observe the prevalence breast diseases of males in our setup.
Method: All cases of male breast disease diagnosed from 1991-97.
Results: One hundred and fifty (150) cases of male breast diseases were diagnosed. Age of the patients ranged from 4 to 90 years, with mean age 38.75 years (median = 33 years). Gynecomastia was the most common pathological abnormality of the male breast (58.66%). Most of the patients presented in the 3rd decade of life. Amongst the malignant conditions, infiltrating ductal carcinoma was most prevalent (82%). Most of the patients with malignancy presented …

Unusual Polymorphisms In Human Immunodeficiency Virus Type 1 Associated With Nonprogressive Infection, Louis Alexander, Emma Weiskopf, Thomas C. Greenough, Nathan C. Gaddis, Marcy C. Auerbach, Michael H. Malim, Stephen J. O'Brien, Bruce D. Walker, John L. Sullivan, Ronald C. Desrosiers

Biology Faculty Articles

Factors accounting for long-term nonprogression may include infection with an attenuated strain of human immunodeficiency virus type 1 (HIV-1), genetic polymorphisms in the host, and virus-specific immune responses. In this study, we examined eight individuals with nonprogressing or slowly progressing HIV-1 infection, none of whom were homozygous for host-specific polymorphisms (CCR5-Δ32, CCR2-64I, and SDF-1-3^'A) which have been associated with slower disease progression. HIV-1 was recovered from seven of the eight, and recovered virus was used for sequencing the full-length HIV-1 genome; full-length HIV-1 genome sequences from the eighth were determined following amplification of viral …

Binding Of Equine Infectious Anemia Virus Rev To An Exon Splicing Enhancer Mediates Alternative Splicing And Nuclear Export Of Viral Mrnas, Michael Belshan, Gregory S. Park, Patricia Bilodeau, C. Martin Stoltzfus, Susan Carpenter

Nebraska Center for Virology: Faculty Publications

In addition to facilitating the nuclear export of incompletely spliced viral mRNAs, equine infectious anemia virus (EIAV) Rev regulates alternative splicing of the third exon of the tat/rev mRNA. In the presence of Rev, this exon of the bicistronic RNA is skipped in a fraction of the spliced mRNAs. In this report, the cis-acting requirements for exon 3 usage were correlated with sequences necessary for Rev binding and transport of incompletely spliced RNA. The presence of a purine-rich exon splicing enhancer (ESE) was required for exon 3 recognition, and the addition of Rev inhibited exon 3 splicing. Glutathione-S-transferase (GST)-Rev bound …

Juvenile Hormone Titer And Morph-Specific Reproduction In The Wing-Polymorphic Cricket, Gryllus Firmus, Gretchen Cisper, Anthony J. Zera, David W. Borst

Anthony Zera Publications

Juvenile hormone titers and reproductive characteristics were measured in adult wing and flight-muscle morphs of the wing-polymorphic cricket, Gryllus firmus, during the first week of adulthood. This species has three morphs: one flight capable morph with fully-developed wings and fully-developed flight muscles [LW(F)], one flightless morph with fully-developed wings and histolyzed (non-functional) flight muscles [LW(H)], and another flightless morph with underdeveloped (short) wings and underdeveloped flight muscles (SW). Both flightless morphs [LW(H) and SW] had larger ovaries which contained a greater number of postvitellogenic eggs compared with the flight capable [LW(F)] morph. The juvenile hormone titer was significantly higher …

Morphological Pattern Of Testicular Tumors, M S. Gill, S H. Shah, I N. Soomro, Naila Kayani, Sheema H. Hasan

Department of Pathology and Laboratory Medicine

Objective:
To find out the mode of presentation, age distribution and the prevalence of various histological subtypes of testicular tumors.
Method:
All consecutive cases of testicular tumors diagnosed in the department of pathology, the Aga Khan University Hospital, Karachi, during the period of eight years (1991-98) were included in this study. Relevant clinical details such as age, clinical presentation and side of involvement of the testis were also recorded, where available.
Results:
During the span of eight years (1991-98), 170 cases of testicular tumors were diagnosed at the Aga Khan University Hospital, Karachi. Most of the tumors were diagnosed in …

Differential Activation Of The Tcpph Promoter By Aphb Determines Biotype Specificity Of Virulence Gene Expression In Vibrio Cholerae, Gabriela Kovacikova, Karen Skorupski

Dartmouth Scholarship

Vibrio cholerae strains of the classical biotype express the genes encoding cholera toxin (CT) and toxin- coregulated pilus (TCP) under a variety of environmental conditions in vitro, whereas El Tor biotype strains express these genes only under specialized culture conditions. We show here that a single base-pair difference at positions 2 65 and 2 66 of the classical and El Tor tcpPH promoters, respectively, is responsible for the differential regulation of virulence gene expression in these two disease-causing biotypes. Analysis of tcpP-lacZ fusions in both V. cholerae and Escherichia coli indicated that transcriptional activation of the El Tor tcpPH promoter …

'Candidatus Xenohaliotis Californiensis', A Newly Described Pathogen Of Abalone, Haliotis Spp., Along The West Coast Of North America, Cs Friedman, Kb Andree, Ka Beauchamp, Jd Moore, Tt Robbins, Jeffrey D. Shields, Rp Hendricks

VIMS Articles

Withering syndrome is a fatal disease of wild and cultured abalone. Haliotis spp., that inhabit the west coast of North America. The aetiological agent of withering syndrome has recently been identified as a member of the family Rickettsiaceae in the order Rickettsiales. Using a combination of morphological, serological, life history and genomic (16S rDNA) characterization. we have identified this bacterium as a unique taxon and propose the provisional status of 'Candidatus Xenohaliotis californiensis', The Gram-negative. obligate intracellular pleomorphic bacterium is found within membrane-bound vacuoles in the cytoplasm of abalone gastrointestinal epithelial cells. The bacterium is not cultivable on synthetic media …