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1999

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Articles 31 - 48 of 48

Full-Text Articles in Microbiology

Pyoveridine Production By Pseudomonas Aeruginosa Exposed To Metals Or An Oxidative Stress Agent, Kim-Hien Thi Dao, Katherine E. Hamer, Christine L. Clark, Lawrence G. Harshman May 1999

Pyoveridine Production By Pseudomonas Aeruginosa Exposed To Metals Or An Oxidative Stress Agent, Kim-Hien Thi Dao, Katherine E. Hamer, Christine L. Clark, Lawrence G. Harshman

School of Biological Sciences: Faculty Publications

Siderophores are low molecular mass compounds used by many microorganisms to scavenge dissolved iron, which is typically rare in environments. Pseudomonas aeruginosa (PAO1) was exposed to metals and methyl viologen in low-iron medium in order to monitor the abundance of a specific siderophore (pyoverdine) and monitor growth over time. In this study it was discovered that cadmium can stimulate pyoverdine abundance. Cadmium may interact with and sequester the Fur regulatory protein, which represses siderophore synthesis under conditions of iron sufficiency. Mercury did not stimulate pyoverdine production at concentrations that strongly inhibited bacterial growth, suggesting that pyoverdine production is not governed …

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The Mycobactericidal Efficacy Of Orthophthalaldehyde And The Comparative Resistances Of Mycobacterium Bovis, Mycobacterium Terrae, And Mycobacterium Chelonae, Richard A. Robison, Adam W. Gregory, G. Bruce Schaalje, Jonathan D. Smart May 1999

The Mycobactericidal Efficacy Of Orthophthalaldehyde And The Comparative Resistances Of Mycobacterium Bovis, Mycobacterium Terrae, And Mycobacterium Chelonae, Richard A. Robison, Adam W. Gregory, G. Bruce Schaalje, Jonathan D. Smart

Faculty Publications

Objectives: To assess the mycobactericidal efficacy of an agent relatively new to disinfection, ortho-phthalaldehyde (OPA) and to compare the resistances of three Mycobacterium species. Mycobacterium bovis (strain BCG) was compared with Mycobacterium chelonae and Mycobacterium terrae to investigate the feasibility of using either of the latter two species in tuberculocidal testing. M chelonae (a rapid grower) and M terrae (an intermediate grower) both grow faster and are less virulent than M bovis (a slow grower).

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Development Of The Suprarostral Plate Of Pipoid Frogs, Rafael O. De Sá, Charles C. Swart Apr 1999

Development Of The Suprarostral Plate Of Pipoid Frogs, Rafael O. De Sá, Charles C. Swart

Biology Faculty Publications

The rostral region of nonpipoid tadpoles has two sets of cartilages, the cornua trabeculae and the suprarostral cartilages, whereas the rostral region in pipoid larvae is occupied by a single and continuous cartilage, the suprarostral plate. The homology of this region in pipoid and nonpipoids tadpoles has been controversial. We examined the early formation and development of the suprarostral plate using serially cross-sectioned specimens of Rhinophrynus, Xenopus, and Hymenochirus. We conclude that the cartilaginous structures present in the rostral area of pipoid and nonpipoid larvae are homologous. Furthermore, we found two different developmental patterns among pipoid larvae. The chondrocranium …

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Interferon Regulatory Factor 2 Represses The Epstein-Barr Virus BamHi Q Latency Promoter In Type Iii Latency, Luwen Zhang, Joseph S. Pagano Apr 1999

Interferon Regulatory Factor 2 Represses The Epstein-Barr Virus BamHi Q Latency Promoter In Type Iii Latency, Luwen Zhang, Joseph S. Pagano

Nebraska Center for Virology: Faculty Publications

Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA-1) is the essential protein for maintenance of the EBV episome and establishment of latency. The BamHI Q promoter (Qp) is used for the transcription of EBNA-1 mRNA in type I and type II latency, which are EBV infection states exemplified by Burkitt’s lymphoma and nasopharyngeal carcinoma. However, Qp is inactive in type III latency, and other promoters (the BamHI C promoter and/or the BamHI W promoter) are used for EBNA-1. The involvement of interferon regulatory factors (IRFs) in the regulation of Qp is suggested by the presence of an essential interferon-stimulated response element …

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Microbiology Of The Oil Fly, Helaeomyia Petrolei, Dana R. Kadavy, Bradley A. Plantz, Christopher A. Shaw, Jill Myatt, Tyler A. Kokjohn, Kenneth Nickerson Apr 1999

Microbiology Of The Oil Fly, Helaeomyia Petrolei, Dana R. Kadavy, Bradley A. Plantz, Christopher A. Shaw, Jill Myatt, Tyler A. Kokjohn, Kenneth Nickerson

Papers in Microbiology

Helaeomyia petrolei larvae isolated from the asphalt seeps of Rancho La Brea in Los Angeles, Calif., were examined for microbial gut contents. Standard counts on Luria-Bertani, MacConkey, and blood agar plates indicated ca. 2 x 105 heterotrophic bacteria per larva. The culturable bacteria represented 15 to 20% of the total population as determined by acridine orange staining. The gut itself contained large amounts of the oil, had no observable ceca, and maintained a slightly acidic pH of 6.3 to 6.5. Despite the ingestion of large amounts of potentially toxic asphalt by the larvae, their guts sustained the growth of …

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Clinico-Morphological Pattern Of Intracranial Tumors In Children, Sajid H. Shah, Irshad N. Soomro, Akbar S. Hussainy, S H. Hassan Mar 1999

Clinico-Morphological Pattern Of Intracranial Tumors In Children, Sajid H. Shah, Irshad N. Soomro, Akbar S. Hussainy, S H. Hassan

Department of Pathology and Laboratory Medicine

Objective:
The objective of present study was to observe the histopathological pattern of intracranial tumors in children (< 15 yrs) and to correlate the site of lesion along with the histological diagnosis.
Setting:
The study included consecutive cases of intracranial tumors diagnosed in children (< 15 yrs.) in the section of histopathology at the Aga Khan University Hospital, Karachi during the period of three years.
Methods:
The initial histological evaluation of these lesions was performed on H and E stained section of paraffin embedded tissue. Special stains and immunohistochemical analysis was done whenever indicated.
Results:
During the study period, fifty-four cases of intracranial tumors were diagnosed in children. The age ranged from 1-1/2 years to 4 years with male to female ratio of 1.1:1. Astrocytoma comprised 39% of all intracranial tumors of childhood. Medulloblastoma …

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Nonspecific Interactions Alter Lipopolysaccharide Patterns And Protein Mobility On Sodium Dodecyl Sulfate Polyacrylamide Gels, Aidong Yuan, R L. Pardy, Catherine P. Chia Mar 1999

Nonspecific Interactions Alter Lipopolysaccharide Patterns And Protein Mobility On Sodium Dodecyl Sulfate Polyacrylamide Gels, Aidong Yuan, R L. Pardy, Catherine P. Chia

Papers in Microbiology

In testing whether bacterial lipopolysaccharide (LPS) was a natural substrate for an esterase from the soil amebae Dictyostelium discoideum, we observed altered banding patterns of the LPS and changed protein mobility on sodium dodecyl sulfate (SDS) polyacrylamide gels after incubation of LPS with the enzyme. The initial interpretation of these results was that the enzyme had removed ester-linked acyl chains from the LPS, leading to a change in its migration on gels. However, esterase inactivated by treatment with either dithiothreitol (DTT), heat, or SDS generated the same mobility shifts. Bovine serum albumin (BSA) also induced the same change in …

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Genetic And Transcriptional Analyses Of The Vibrio Cholerae Mannose-Sensitive Hemagglutinin Type 4 Pilus Gene Locus, Jane W. Marsh, Ronald K. Taylor Feb 1999

Genetic And Transcriptional Analyses Of The Vibrio Cholerae Mannose-Sensitive Hemagglutinin Type 4 Pilus Gene Locus, Jane W. Marsh, Ronald K. Taylor

Dartmouth Scholarship

The mannose-sensitive hemagglutinin (MSHA) of the Vibrio cholerae O1 El Tor biotype is a member of the family of type 4 pili. Type 4 pili are found on the surface of a variety of gram-negative bacteria and have demonstrated importance as host colonization factors, bacteriophage receptors, and mediators of DNA transfer. The gene locus required for the assembly and secretion of the MSHA pilus has been localized to a 16.7-kb region of the V. cholerae chromosome. Sixteen genes required for hemagglutination, including five that encode prepilin or prepilin-like proteins, have been identified. Examination of MSHA-specific cDNAs has localized two promoters …

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Osteological Analysis Of The Killifish Genus Cynolebias (Cyprinodontiformes: Rivulidae), Marcelo Loureiro, Rafael O. De Sá Jan 1999

Osteological Analysis Of The Killifish Genus Cynolebias (Cyprinodontiformes: Rivulidae), Marcelo Loureiro, Rafael O. De Sá

Biology Faculty Publications

Relationships among the species of the annual fish Cynolebias are unclear. An analysis of the variation and utility of osteological characters for phylogenetic analysis was done using cleared and double-stained specimens representing 21 species of Cynolebias. This analysis showed that some of the characters previously used to diagnose this genus and some of the species are polymorphic. Osteologically, Cynolebias can be diagnosed by the following synapomorphies: (1) triangular-shaped parietal, (2) vomer positioned ventral to the parasphenoid, (3) long ventral process of the dentary, (4) teeth on fourth ceratobranchial, and (5) teeth on first epibranchial. In addition, characters that help …

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Relationship Between Udp-Glucose 4-Epimerase Activity And Oligoglucose Glycoforms In Two Strains Of Neisseria Meningitidis, F K. Lee, B W. Gibson, William Melaugh, A Zaleski, M A. Apicella Jan 1999

Relationship Between Udp-Glucose 4-Epimerase Activity And Oligoglucose Glycoforms In Two Strains Of Neisseria Meningitidis, F K. Lee, B W. Gibson, William Melaugh, A Zaleski, M A. Apicella

Chemistry Faculty Publications

Sodium dodecyl sulfate-polyacrylamide gel analysis of lipooligosaccharide (LOS) from Neisseria meningitidis has demonstrated considerable microheterogeneity in the variable region of LOS due to the presence of novel glycoforms. As a step toward understanding the basis for the expression of these novel glycoforms, we have examined the LOS structures and UDP-glucose 4-epimerase (epimerase) activity levels in two strains (NMB and MA-1) and their respective galE mutants. Strain NMB was found to have low epimerase activity and to contain multiple glycoforms, some of which appear to contain only glucose sugars. The galE mutant had only the oligoglucose glycoforms. Strain MA-1 had higher …

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Microbial Colonization Of The Cloacae Of Nestling Tree Swallows, Tamara K. Mills, Michael P. Lombardo, Patrick A. Thorpe Jan 1999

Microbial Colonization Of The Cloacae Of Nestling Tree Swallows, Tamara K. Mills, Michael P. Lombardo, Patrick A. Thorpe

Peer Reviewed Publications

Microbes have the potential to be important selective forces in many aspects of avian biology. Microbes can affect fitness as a result of either their pathogenic or beneficial effects on host health. Little is known about the chronology of microbial colonization of nestlings or the effects of microbes on fledgling condition. We set out to (1) characterize the time course of microbial colonization of the cloacae of nestling Tree Swallows (Tachycineta bicolor), (2) examine the relationship between cloacal microbes and fledgling condition, and (3) determine if nest mates had similar assemblages of cloacal microbes. We repeatedly measured nestlings …

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Humboldt Journal Of Microbiology: Volume 2, Number 1- May 1999, Press Humboldt Jan 1999

Humboldt Journal Of Microbiology: Volume 2, Number 1- May 1999, Press Humboldt

Humboldt Journal of Microbiology

No abstract provided.

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Nucleotide Sequence Of The Streptococcin A-Ff22 Lantibiotic Regulon: Model For Production Of The Lantibiotic Sa-Ff22 By Strains Of Streptococcus Pyogenes, Robert E. Mclaughlin, Joseph J. Ferretti, Wayne L. Hynes Jan 1999

Nucleotide Sequence Of The Streptococcin A-Ff22 Lantibiotic Regulon: Model For Production Of The Lantibiotic Sa-Ff22 By Strains Of Streptococcus Pyogenes, Robert E. Mclaughlin, Joseph J. Ferretti, Wayne L. Hynes

Biological Sciences Faculty Publications

Streptococcin A-FF22 (SA-FF22) is a type AII linear lantibiotic produced by Streptococcus pyogenes strain FF22. Sequence analysis of an approximate 10 kb region of DNA showed it to contain nine open reading frames arranged in three operons responsible for regulation, biosynthesis and immunity of SA-FF22. This region is organized similarly to the Lactococcus lactis lacticin 481 region, however, unlike lacticin 481, a two-component regulatory system is essential for SA-FF22 production. located immediately downstream of the scn region is a putative transposase gene, the presence of which supports earlier data that indicated a mobile nature to this region. (©) 1999 Published …

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Characterization Of The Jembrana Disease Virus Tat Gene And The Cis- And Trans-Regulatory Elements In Its Long Terminal Repeats, Hexin Chen, Graham Wilcox, Gde Kertayadnya, Charles Wood Jan 1999

Characterization Of The Jembrana Disease Virus Tat Gene And The Cis- And Trans-Regulatory Elements In Its Long Terminal Repeats, Hexin Chen, Graham Wilcox, Gde Kertayadnya, Charles Wood

Nebraska Center for Virology: Faculty Publications

Jembrana disease virus (JDV) is a newly identified bovine lentivirus that is closely related to the bovine immunodeficiency virus (BIV). JDV contains a tat gene, encoded by two exons, which has potent transactivation activity. Cotransfection of the JDV tat expression plasmid with the JDV promoter chloramphenicol acetyltransferase (CAT) construct pJDV-U3R resulted in a substantial increase in the level of CAT mRNA transcribed from the JDV long terminal repeat (LTR) and a dramatic increase in the CAT protein level. Deletion analysis of the LTR sequences showed that sequences spanning nucleotides 268 to 153, including the TATA box and the predicted first …

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Chlorella Virus Pbcv-1 Encodes A Functional Homospermidine Synthase, Annette Kaiser, Michael Vollmert, Dorothea Tholl, Michael V. Graves, James Gurnon, Weimei Xing, Amber D. Lisec, Kenneth Nickerson, James L. Van Etten Jan 1999

Chlorella Virus Pbcv-1 Encodes A Functional Homospermidine Synthase, Annette Kaiser, Michael Vollmert, Dorothea Tholl, Michael V. Graves, James Gurnon, Weimei Xing, Amber D. Lisec, Kenneth Nickerson, James L. Van Etten

Kenneth Nickerson Papers

Sequence analysis of the 330-kb genome of chlorella virus Paramecium bursaria chlorella virus 1 (PBCV-1) revealed an open reading frame, A237R, that encodes a protein with 34% amino acid identity to homospermidine synthase from Rhodopseudomonas viridis. Expression of the a237r gene product in Escherichia coli established that the recombinant enzyme catalyzes the NAD+-dependent formation of homospermidine from two molecules of putrescine. The a237r gene is expressed late in PBCV-1 infection. Both uninfected and PBCV-1-infected chlorella, as well as PBCV-1 virions, contain homospermidine, along with the more common polyamines putrescine, spermidine, and cadaverine. The total number of polyamine …

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Carmoviruses (Tombusviridae), Feng Qu, Thomas Jack Morris Jan 1999

Carmoviruses (Tombusviridae), Feng Qu, Thomas Jack Morris

School of Biological Sciences: Faculty Publications

Carmovirus is one of two officially recognized genera of Tombusviridae. Members of Tombusviridae all have icosahedral virions of about 30 nm in diameter with T = 3 symmetry that consists of 180 coat protein (CP) subunits of about 38- 43 kDa and a single-stranded (ss) RNA genome ranging in size from 4.0 to 4.7 kb. Carmoviruses share recognizable sequence similarity in both the polymerase and structural genes with members of the other genus, Tombusvirus. Sequence comparisons and phylogenetic analysis of these genes support the view that the genera are distinct but closely related. In addition, the genome organization of the …

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Construction Of An Escherichia Coli Lac Repressor-Based System To Study Human Cytomegalovirus Gene Expression, Laura Fernanda Cageao-Luchetti Jan 1999

Construction Of An Escherichia Coli Lac Repressor-Based System To Study Human Cytomegalovirus Gene Expression, Laura Fernanda Cageao-Luchetti

Theses and Dissertations in Biomedical Sciences

An Escherichia coli lac repressor-based system was developed to study the roles of human cytomegalovirus (HCMV) genes during viral replication. To this end, a recombinant HCMV expressing the lac repressor was generated (RVlac), and an HCMV-specific promoter was targeted for conditional expression by inserting the lac operator sequence. The promoter of a nonessential gene was chosen in order to be able to assess parameters of repression and derepression of the operator-containing promoter in the endogenous locus, without having virus growth dependent on the specific inducer isopropylthiogalactoside (IPTG). The feasibility of this approach to conditionally express an HCMV promoter …

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Determination Of The Microbiological Load Of The Principal Meat Products Sold In The Markets Of Riobamba, Miguel Angel Castillo Palacios Jan 1999

Determination Of The Microbiological Load Of The Principal Meat Products Sold In The Markets Of Riobamba, Miguel Angel Castillo Palacios

Theses and Dissertations

This investigation was done with the objective to determine the microbiological load of the main meat products such as: beef, chicken meat, sausage, and viena sausage which are sold in the Riobamba city markets. This investigation was carried out in the Microbiological Laboratory Livestock Science faculty of the Polytechnical Superior school. Specific chemical products were used to determine mesofilas (37 degrees C), xicrofilas (5 degrees C), and termofilas bacteria which did not develop at 45 degrees C, however exicrofilas and mesofilas bacteria were found in every market and meat product in this study. The meat product hygiene is the same …

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