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Articles 7531 - 7560 of 8416

Full-Text Articles in Microbiology

Association Of Epstein Barr Virus (Ebv) With Nasopharyngeal Carcinoma (Npc), S H. Shah, I N. Soomro, S Haroon, T Moatter Jun 2000

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 …

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Breast Diseases In Males--A Morphological Review Of 150 Cases, M S. Gill, N Kayani, M N. Khan, S H. Hasan Jun 2000

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 …

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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 May 2000

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 …

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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 May 2000

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 …

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Molecular Evolution Of Insecticidal Spore-Forming Bacteria, John Pool Apr 2000

Molecular Evolution Of Insecticidal Spore-Forming Bacteria, John Pool

Honors Theses

Molecular methods are increasingly being used to determine the phylogeny of microorganisms. This research was intended to determine phylogenetic relationships for bacteria of the species Bacillus thuringiensis and other members of the Bacillus cereus group. Each strain was analyzed by its sasp-B gene sequence to determine its species classification and relation to other strains studied. Results of this study indicated that according to the sasp-B gene tree, the species Bacillus thuringiensis is a paraphyletic with respect to both Bacillus cereus and Bacillus anthracis. Some unexpected results and implications for species designations are also discussed.

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Juvenile Hormone Titer And Morph-Specific Reproduction In The Wing-Polymorphic Cricket, Gryllus Firmus, Gretchen Cisper, Anthony J. Zera, David W. Borst Apr 2000

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 …

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Molecular Taxonomy Of The Lichen Genus Heterodermia, Linda Hirschberger Apr 2000

Molecular Taxonomy Of The Lichen Genus Heterodermia, Linda Hirschberger

Seton Hall University Dissertations and Theses (ETDs)

Heterodermia is lichen consisting of a fungus and algae. Morphology and chemistry cannot provide definitive evidence for the identity of Heterodermia because various species have very similar morphologies that cannot always be distinguished. Other species only differ by the presence or absence of secondary chemicals detected. by specific chemical tests, which makes distinguishing between two species difficult. The objective of this project is to use Restriction Fragment Length Polymorphisms (RFLPs) to determine how closely related each Heterodermia species is to one another. RFLPs will also be used to determine how closely related a species is to its equal in another …

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Kinetic Characterization Of Tetracycline Binding And Release By Demineralized Bone - Dfdba, Orner Kabil Apr 2000

Kinetic Characterization Of Tetracycline Binding And Release By Demineralized Bone - Dfdba, Orner Kabil

Biological Sciences Theses & Dissertations

The microbial etiology of periodontal diseases has led to widespread research in the development of methods and local delivery systems to increase the efficacy of antibiotic therapy. Several drug delivery systems employing biodegradable and nonbiodegradable carriers have been shown to release antibiotics directly into periodontal pockets. The purpose of this study was to determine the binding and release kinetics of tetracycline by demineralized bone. Further aspects of the study include in vitro evaluation of DFDBA (demineralized freeze-dried bone allografts) as a tetracycline carrier system for periodontal therapy. Experiments were performed which employed different tetracycline concentrations with constant amounts of bone …

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Morphological Pattern Of Testicular Tumors, M S. Gill, S H. Shah, I N. Soomro, Naila Kayani, Sheema H. Hasan Apr 2000

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 …

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Differential Activation Of The Tcpph Promoter By Aphb Determines Biotype Specificity Of Virulence Gene Expression In Vibrio Cholerae, Gabriela Kovacikova, Karen Skorupski Mar 2000

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 …

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Intracellular Traits Of Chimeric Trnalys3-Ribozymes And Their Inhibition Of Hiv, Zongli Chang Mar 2000

Intracellular Traits Of Chimeric Trnalys3-Ribozymes And Their Inhibition Of Hiv, Zongli Chang

Loma Linda University Electronic Theses, Dissertations & Projects

Host tRNALYs3is the primer recruited by HIV-1 for initiating reverse transcription. When ribozymes targeted upstream of the primer binding site of the HIV-1 genome are tethered to the 3' end of the tRNALYs3, it is expected that the tRNA will carry the ribozymes into the virions. We made constructs that express chimeric tRNALYs3- ribozymes from internal tRNA promoters. These chimeras were also adjoined downstream of a U6 promoter, resulting in a hybrid U6/tRNA expression cassette with extragenic U6 and intragenic tRNA promoters. Juxtaposition of the tRNA and U6 promoters significantly enhanced expression levels compared to the tRNA promoter alone. A …

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Jembrana Disease Virus Tat Can Regulate Human Immunodeficiency Virus (Hiv) Long Terminal Repeat-Directed Gene Expression And Can Substitute For Hiv Tat In Viral Replication, Hexin Chen, Jun He, Steven Fong, Graham Wilcox, Charles Wood Mar 2000

Jembrana Disease Virus Tat Can Regulate Human Immunodeficiency Virus (Hiv) Long Terminal Repeat-Directed Gene Expression And Can Substitute For Hiv Tat In Viral Replication, Hexin Chen, Jun He, Steven Fong, Graham Wilcox, Charles Wood

Nebraska Center for Virology: Faculty Publications

Jembrana disease virus (JDV) is a bovine lentivirus genetically similar to bovine immunodeficiency virus; it causes an acute and sometimes fatal disease in infected animals. This virus carries a very potent Tat that can strongly activate not only its own long terminal repeat (LTR) but also the human immunodeficiency virus (HIV) LTR. In contrast, HIV Tat cannot reciprocally activate the JDV LTR (H. Chen, G. E. Wilcox, G. Kertayadnya, and C. Wood, J. Virol. 73:658–666, 1999). This indicates that in transactivation JDV Tat may utilize a mechanism similar to but not the same as that of the HIV Tat. To …

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Interferon Regulatory Factor 7 Is Induced By Epstein-Barr Virus Latent Membrane Protein 1, Luwen Zhang, Joseph S. Pagono Feb 2000

Interferon Regulatory Factor 7 Is Induced By Epstein-Barr Virus Latent Membrane Protein 1, Luwen Zhang, Joseph S. Pagono

Nebraska Center for Virology: Faculty Publications

Infection by Epstein-Barr virus (EBV) generates several types of latency with different profiles of gene expression but with expression of Epstein-Barr nuclear antigen 1 (EBNA-1) in common. The BamHI Q promoter (Qp) is used for the transcription of EBNA-1 mRNA in type I latency, which is an EBV infection state exemplified by Burkitt’s lymphoma (BL). However, Qp is inactive in type III latency, and other promoters (C/Wp) are used for transcription of EBNA-1, which raises the question of how usage of these promoters is governed. Interferon (IFN) regulatory factor 7 (IRF-7) was identified first as a negative regulator of …

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Cap-Independent Translational Enhancement Of Turnip Crinkle Virus Genomic And Subgenomic Rnas, Feng Qu, Thomas Jack Morris Feb 2000

Cap-Independent Translational Enhancement Of Turnip Crinkle Virus Genomic And Subgenomic Rnas, Feng Qu, Thomas Jack Morris

Nebraska Center for Virology: Faculty Publications

The presence of translational control elements and cap structures has not been carefully investigated for members of the Carmovirus genus, a group of small icosahedral plant viruses with positive-sense RNA genomes. In this study, we examined both the 5’ and 3’ untranslated regions (UTRs) of the turnip crinkle carmovirus (TCV) genomic RNA (4 kb) as well as the 5’ UTR of the coat protein subgenomic RNA (1.45 kb) for their roles in translational regulation. All three UTRs enhanced translation of the firefly luciferase reporter gene to different extents. Optimal translational efficiency was achieved when mRNAs contained both 5’ and 3’ …

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Integronlike Structures In Campylobacter Spp. Of Human And Animal Origin, Brigid Lucey, D. Crowley, P. Moloney, B. Cryan, M. Daly, F. O'Halloran, E. J. Threlfall, S. Fanning Feb 2000

Integronlike Structures In Campylobacter Spp. Of Human And Animal Origin, Brigid Lucey, D. Crowley, P. Moloney, B. Cryan, M. Daly, F. O'Halloran, E. J. Threlfall, S. Fanning

Department of Biological Sciences Publications

Resistance to antimicrobial agents used to treat severe Campylobacter spp. gastroenteritis is increasing worldwide. We assessed the antimicrobial resistance patterns of Campylobacter spp. isolates of human and animal origin. More than half (n = 32) were resistant to sulphonamide, a feature known to be associated with the presence of integrons. Analysis of these integrons will further our understanding of Campylobacter spp. epidemiology.

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Cyanonews (Vol. 15, No. 1, July 2000), Jeff Elhai Jan 2000

Cyanonews (Vol. 15, No. 1, July 2000), Jeff Elhai

CyanoNews

CyanoNews was a newsletter that served the cyanobacteriological community from 1985 to 2003, with content provided by readers (sort of a blog before there were blogs). The newsletter reported new findings from the lab, summaries of recent meetings (often provided by graduate students and post-docs entering the field), positions sought or available, life transitions, a compendium of recent cyanobacteria-related articles, and other items of interest to those who study cyanobacteria.

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Activation Of P38 Mitogen-Activated Protein Kinase And C-Jun Nh2-Terminal Kinase By Double-Stranded Rna And Encephalomyocarditis Virus: Involvement Of Rnase L, Protein Kinase R, And Alternative Pathways, Mihail S. Iordanov, Jayashree M. Paranjape, Aimin Zhou, John Wong, Bryan R. G. Williams, Eliane F. Meurs, Robert H. Silverman, Bruce E. Magun Jan 2000

Activation Of P38 Mitogen-Activated Protein Kinase And C-Jun Nh2-Terminal Kinase By Double-Stranded Rna And Encephalomyocarditis Virus: Involvement Of Rnase L, Protein Kinase R, And Alternative Pathways, Mihail S. Iordanov, Jayashree M. Paranjape, Aimin Zhou, John Wong, Bryan R. G. Williams, Eliane F. Meurs, Robert H. Silverman, Bruce E. Magun

CUP Faculty Research

Double-stranded RNA (dsRNA) accumulates in virus-infected mammalian cells and signals the activation of host defense pathways of the interferon system. We describe here a novel form of dsRNA-triggered signaling that leads to the stimulation of the p38 mitogen-activated protein kinase (p38 MAPK) and the c-Jun NH2-terminal kinase (JNK) and of their respective activators MKK3/6 and SEK1/MKK4. The dsRNA-dependent signaling to p38 MAPK was largely intact in cells lacking both RNase L and the dsRNA-activated protein kinase (PKR), i.e., the two best-characterized mediators of dsRNA-triggered antiviral responses. In contrast, activation of both MKK4 and JNK by dsRNA was greatly …

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Identification Of The Transactivation Domain Of The Transcription Factor Sox-2 And An Associated Co-Activator, Tamara K. Nowling, Lance R. Johnson, Matthew S. Wiebe, Angie Rizzino Jan 2000

Identification Of The Transactivation Domain Of The Transcription Factor Sox-2 And An Associated Co-Activator, Tamara K. Nowling, Lance R. Johnson, Matthew S. Wiebe, Angie Rizzino

Nebraska Center for Virology: Faculty Publications

The importance of interactions between Sox and POU transcription factors in the regulation of gene expression is becoming increasingly apparent. Recently, many examples of the involvement of Sox-POU partnerships in transcription have been discovered, including a partnership between Sox-2 and Oct-3. Little is known about the mechanisms by which these factors modulate transcription. To better understand the molecular interactions involved, we mapped the location of the transactivation do-main of Sox-2. This was done in the context of its interaction with Oct-3, as well as its ability to transactivate as a fusion protein linked to the DNA-binding domain of Gal4. Both …

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Quantitative Image Analysis Of Simian Immunodeficiency Virus Replication In Macrophages Coinfected With Mycobacterium Avium Complex, Qingsheng Li, Keith G. Mansfield, Andrew Lackner, Ashley T. Haase Jan 2000

Quantitative Image Analysis Of Simian Immunodeficiency Virus Replication In Macrophages Coinfected With Mycobacterium Avium Complex, Qingsheng Li, Keith G. Mansfield, Andrew Lackner, Ashley T. Haase

Qingsheng Li Publications

Mycobacterium avium is the most frequent cause of disseminated bacterial infection in patients with human immunodeficiency virus type 1 infection and in rhesus macaques with simian immunodeficiency virus (SIV) infection. This animal model of AIDS was used to test the hypothesis that this frequent association is the result of reciprocal enhancement of replication of both microorganisms. The replication of M. avium and SIV was analyzed in lymphatic tissues obtained from rhesus macaques experimentally inoculated with SIVmac who developed or remained free of overt M. avium infection. In situ hybridization, quantitative image analysis, and staining of M. avium and of macrophages …

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Construction Of Escherichia Coli Arginine Repressor Fusion Protein And Analysis Of Its Function In Xer Site-Specific Recombination, Kholis Abdulrachim Jan 2000

Construction Of Escherichia Coli Arginine Repressor Fusion Protein And Analysis Of Its Function In Xer Site-Specific Recombination, Kholis Abdulrachim

Student Works (2000-2009)

In addition to its role in L-arginine biosynthesis in Escherichia coli, arginine repressor (ArgR), the product of the argR gene, also plays an essential role as an obligate accessory protein in Xer site-specific recombination system. A structure-function relationship study of ArgR was performed to understand more about its role in Xcr site-specific recombination. Fusion proteins between ArgRWT (wild-type ArgR) and a biotinylated peptide as well as between ArgRNV (a mutant ArgR) and a biotinylated peptide were constructed. The biotinylated peptide was fused in frame to the amino-tenninus of ArgR WT and ArgRNV, respectively. Xer recombination assays showed that the ArgRWT-biotinylated …

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Review Of Searching For Hawa's Secret, John Stephen Brantley Jan 2000

Review Of Searching For Hawa's Secret, John Stephen Brantley

Faculty & Staff Research & Creative Activity

No abstract provided.

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Review Of Searching For Hawa's Secret, John Brantley Jan 2000

Review Of Searching For Hawa's Secret, John Brantley

Faculty & Staff Research & Creative Activity

No abstract provided.

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Response Of The Tick Dermacentor Variabilis (Acari: Ixodidae) To Hemocoelic Inoculation Of Borrelia Burgdorferi (Spirochetales), Robert Johns, Daniel E. Sonenshine, Wayne L. Hynes Jan 2000

Response Of The Tick Dermacentor Variabilis (Acari: Ixodidae) To Hemocoelic Inoculation Of Borrelia Burgdorferi (Spirochetales), Robert Johns, Daniel E. Sonenshine, Wayne L. Hynes

Biological Sciences Faculty Publications

When Borrelia burgdorferi B31 low passage strain spirochetes were directly injected into the hemocoel of Dermacentor variabilis(Say) females, the bacteria were cleared from the hemocoel within < 24 h. Viable spirochetes were not found in hemolymph, salivary gland, or ovary tissues by subculturing or by IFA. The hemocyte population increased ≈6 times within the first 6 h after inoculation compared with the uninoculated controls. In contrast, the soluble total hemolymph protein content decreased inversely with the increase in hemocytes. Borreliacidal activity was demonstrated with cell-free hemolymph from D. variabilis. In vitro antimicrobial assays using hemolymph from borrelia-challenged and nonchallenged ticks resulted in 72% spirochete reductions compared with only 11.5%, respectively, within 1 h. Additional evidence of induced antimicrobial hemolymph protein activity was demonstrated by SDS-PAGE, which revealed upregulation of a lysozyme-like peptide (≈ 15 kDa) (22% increase) and the induction of a ≈ 5.8 kDa peptide in the B. burgdorferi-challenged ticks. In contrast with the nonvector borne Bacillus subtilis …

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Genetic Diversity Of Salmonella Typhi, Satheesh Nair Jan 2000

Genetic Diversity Of Salmonella Typhi, Satheesh Nair

Student Works (2000-2009)

Typhoid fever is a unique human septemic infection caused by Salmonella typhi. Typhoid fever is still an important public health problem in many developing countries. The continuing presence of the disease in endemic areas and emergence of multidrug- resistant strains in many developing countries as well as the increasing reports from developed countries has renewed the interest to better understand the epidemiology of typhoid fever and some aspects of its pathogenesis. Characterization of S. typhi strains in different epidemiological settings depends largely on the utility of highly precise molecular typing tools. A convenient, versatile and safe method for preparing bacterial …

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Antigenic Epitope Analysis Of The P101 Nucleocapsid Protein Of Human Herpes Virus 6 (Var.B), Katherine Anne Francis Jan 2000

Antigenic Epitope Analysis Of The P101 Nucleocapsid Protein Of Human Herpes Virus 6 (Var.B), Katherine Anne Francis

Student Works (2000-2009)

Human herpes virus 6 (HHV6) is an ubiquitous, lymphoproliferative P-herpesvirus, which infects almost all individuals during infancy and persists lifelong. Two variants of HHV6 (A and B) have been described. The present study is on HHV6B, which causes exanthem subitum, also known as roseola infantum, a common febrile childhood illness. Two methods of detection for anti-HHV6B in body fluids were used, being indirect immunofluorescence assay (IFA) and peptidylated pin-ELISA. For IFA, the target cells were HHV68-infected human cord blood mononuclear cells (HCBMC). Ninety eight infant sera were tested by IFA and all were found to be IgG-HHV6 positive. Seventeen breast …

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Humboldt Journal Of Microbiology: Volume 3, Number 1- May 2000, Press Humboldt Jan 2000

Humboldt Journal Of Microbiology: Volume 3, Number 1- May 2000, Press Humboldt

Humboldt Journal of Microbiology

No abstract provided.

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The Molecular Characterisation Of Selected Epidemic Associated Gram Negative Pathogens In Southern Ireland, Mairéad Daly Jan 2000

The Molecular Characterisation Of Selected Epidemic Associated Gram Negative Pathogens In Southern Ireland, Mairéad Daly

Theses

This study was undertaken to evaluate various molecular techniques for the analysis of Gram negative bacterial associated epidemics. The first investigation dealt with bovine mastitis outbreaks, where the causative agent was identified as Pseudomonas aeruginosa. Epidemiological findings, suggested that all herds were infected from teat wipes that were contaminated with this organism. Initial investigations using the polymerase chain reaction (PCR), indicated a possible clonal relationship between all outbreak linked strains, with one exception. This finding was confirmed following pulsed-field gel electrophoresis (PFGE) and ribotype analysis. PCR was again employed to study a rather unusual epidemic, involving Salmonella tel-el-kebir over a …

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Role Of Esterase Gp70 And Its Influence On Growth And Development Of Dictyostelium Discoideum, Aidong Yuan, Catherine P. Chia Jan 2000

Role Of Esterase Gp70 And Its Influence On Growth And Development Of Dictyostelium Discoideum, Aidong Yuan, Catherine P. Chia

Papers in Microbiology

Gp70 is an esterase originally called crystal protein because of its presence in crystalline structures in aggregation-competent Dictyostelium discoideum cells. Although postulated to break down spore coats, the function of gp70 in vivo was incompletely investigated. Our immunolocalization and biochemical studies of vegetative D. discoideum amoebae show that gp70 was recruited to phagosomes and found in lysosomes. Purified gp70 was effective at hydrolyzing naphthyl substrates with acyl chains typical of lipids and lipopolysaccharides, indicating that the gp70 was involved in digesting endocytosed molecules. The activity of purified gp70 was inhibited by reductants that retarded its electrophoretic mobility and verified the …

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Hyaluronidases Of Gram-Positive Bacteria, Wayne L. Hynes, Sheryl Lynne Walton Jan 2000

Hyaluronidases Of Gram-Positive Bacteria, Wayne L. Hynes, Sheryl Lynne Walton

Biological Sciences Faculty Publications

Bacterial hyaluronidases, enzymes capable of breaking down hyaluronate, are produced by a number of pathogenic Gram-positive bacteria that initiate infections at the skin or mucosal surfaces. Since reports of the hyaluronidases first appeared, there have been numerous suggestions as to the role of the enzyme in the disease process. Unlike some of the other more well studied virulence factors, much of the information on the role of hyaluronidase is speculative, with little or no data to substantiate proposed roles. Over the last 5 years, a number of these enzymes from Gram-positive organisms have been cloned, and the nucleotide sequence determined. …

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The Global Carbon Metabolism Regulator Crc Is A Component Of A Signal Transduction Pathway Required For Biofilm Development By Pseudomonas Aeruginosa, George A. O'Toole, Karine A. Gibbs, Paul W. Hager, Paul V. Phibbs, Roberto Kolter Jan 2000

The Global Carbon Metabolism Regulator Crc Is A Component Of A Signal Transduction Pathway Required For Biofilm Development By Pseudomonas Aeruginosa, George A. O'Toole, Karine A. Gibbs, Paul W. Hager, Paul V. Phibbs, Roberto Kolter

Dartmouth Scholarship

The transition from a planktonic (free-swimming) existence to growth attached to a surface in a biofilm occurs in response to environmental factors, including the availability of nutrients. We show that the catabolite repression control (Crc) protein, which plays a role in the regulation of carbon metabolism, is necessary for biofilm formation in Pseudomonas aeruginosa. Using phase-contrast microscopy, we found that a crc mutant only makes a dispersed monolayer of cells on a plastic surface but does not develop the dense monolayer punctuated by microcolonies typical of the wild-type strain. This is a phenotype identical to that observed in mutants …

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