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2003

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Articles 1 - 30 of 62

Full-Text Articles in Microbiology

Antibacterial Activities Of Constituents From Isolona Cauliflora And Cleistochlamys Kirkii, Ac Odebode, Sjm Mdachi, Cc Joseph, Bn Irungu Dec 2003

Antibacterial Activities Of Constituents From Isolona Cauliflora And Cleistochlamys Kirkii, Ac Odebode, Sjm Mdachi, Cc Joseph, Bn Irungu

Tanzania Journal of Science

Antibacterial activities of caulindole D, a mixture of caulindole E and F, pinocembrin and an oxyheptanoid (cleistenolide), obtained from stem barks of Isolona cauliflora and Cleistochlamys kirkii, on Staphylococcus aureus and Pseudomonas phaseolicola were determined. An in vitro assay test by paper disc method showed that the caulindole D, E and F from Isolona cauliflora produced no inhibition zone on both bacteria pathogens at 100-200 ppm while cleistochlamic acid from C. kirkii showed weak to moderate inhibition zone at 100-200 ppm. At concentration above 200 ppm, the bacteria pathogens were inhibited by all the compounds isolated from the plant extracts. …

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Phenotype Of The Triplo-Lethal Locus Of Drosophila Melanogaster And Its Suppression By Hyperoxia, Laura K. Smoyer, Douglas R. Dorer, Kenneth W. Nickerson, Alan C. Christensen Dec 2003

Phenotype Of The Triplo-Lethal Locus Of Drosophila Melanogaster And Its Suppression By Hyperoxia, Laura K. Smoyer, Douglas R. Dorer, Kenneth W. Nickerson, Alan C. Christensen

Papers in Microbiology

The Triplo-lethal locus (Tpl) of Drosophila is both triplo-lethal and haploinsufficient, but the function of the locus is unknown. We have examined Tpl-aneuploid embryos and find that, in both trisomics and monosomics, the midgut shows extensive cell death and the tracheae are abnormal. Shortly thereafter, all tissues die. PCR-based genotyping of individual embryos and larvae show that this phenotype occurs in the trisomics after hatching and in the monosomics before hatching. Weak alleles of the interacting gene Su(Tpl) delay the death of Tpl trisomics, but they still show the same tracheal and midgut phenotypes before dying. Hyperoxia (45% oxygen) …

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The Endocrine Regulation Of Wing Polymorphism In Insects: State Of The Art, Recent Surprises, And Future Directions, Anthony J. Zera Nov 2003

The Endocrine Regulation Of Wing Polymorphism In Insects: State Of The Art, Recent Surprises, And Future Directions, Anthony J. Zera

Anthony Zera Publications

The endocrine mechanisms controlling the development and reproduction of flight-capable (long-winged) and flightless (short-winged or wingless) morphs of wing-polymorphic insects have been intensively investigated. The "classical model," put forward in the early 1960s, postulates that morph-specific differences in development and reproduction are caused by variation in the titers of juvenile hormone (JH) and/or ecdysone. Despite decades of study, the importance of these hormones in regulating wing polymorphism in aphids and planthoppers remains uncertain. This uncertainly is largely a consequence of technical and size constraints which have severely limited the types of endocrine approaches that can be used in these insects. …

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Initial State Of The Drosophila Eye Before Dorsoventral Specification Is Equivalent To Ventral, Amit Singh, Kwang-Wook Choi Nov 2003

Initial State Of The Drosophila Eye Before Dorsoventral Specification Is Equivalent To Ventral, Amit Singh, Kwang-Wook Choi

Biology Faculty Publications

Dorsoventral (DV) patterning is crucial for eye development in invertebrates and higher animals. DV lineage restriction is the primary event in undifferentiated early eye primordia of Drosophila. InDrosophila eye disc, a dorsal-specific GATA family transcription factor pannier (pnr) controls Iroquois-Complex (Iro-C) genes to establish the dorsal eye fate whereas Lobe (L), which is involved in controlling a Notch ligand Serrate (Ser), is specifically required for ventral growth. However, fate of eye disc cells before the onset of dorsal expression of pnr and Iro-C is not known. We show that L/Ser …

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Comprehensive Analysis Of Class I And Class Ii Hla Antigens And Chronic Hepatitis B Virus Infection, Chloe L. Thio, David L. Thomas, Peter Karacki, Xiaojiang Gao, Darlene Marti, Richard A. Kaslow, James J. Goedert, Margaret Hilgartner, Steffanie A. Strathdee, Priya Duggal, Stephen J. O'Brien, Jacquie Astemborski, Mary Carrington Nov 2003

Comprehensive Analysis Of Class I And Class Ii Hla Antigens And Chronic Hepatitis B Virus Infection, Chloe L. Thio, David L. Thomas, Peter Karacki, Xiaojiang Gao, Darlene Marti, Richard A. Kaslow, James J. Goedert, Margaret Hilgartner, Steffanie A. Strathdee, Priya Duggal, Stephen J. O'Brien, Jacquie Astemborski, Mary Carrington

Biology Faculty Articles

Following an acute hepatitis B virus (HBV) infection, clearance or persistence is determined in part by the vigor and breadth of the host immune response. Since the human leukocyte antigen system (HLA) is an integral component of the immune response, we hypothesized that the highly polymorphic HLA genes are key determinants of viral clearance. HLA class I and II genes were molecularly typed in 194 Caucasian individuals with viral persistence and 342 matched controls who had cleared the virus. A single class I allele, A*0301 (odds ratio [OR], 0.47; 95% confidence interval [CI], 0.30 to 0.72; P = 0.0005) was …

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Subpopulations Of Equine Infectious Anemia Virus Rev Coexist In Vivo And Differ In Phenotype, Prasith Baccam, Robert J. Thompson, Yuxing Li, Wendy O. Sparks, Michael Belshan, Karin S. Dorman, Yvonne Wannemuehler, J. Lindsay Oaks, James L. Cornette, Susan Carpenter Nov 2003

Subpopulations Of Equine Infectious Anemia Virus Rev Coexist In Vivo And Differ In Phenotype, Prasith Baccam, Robert J. Thompson, Yuxing Li, Wendy O. Sparks, Michael Belshan, Karin S. Dorman, Yvonne Wannemuehler, J. Lindsay Oaks, James L. Cornette, Susan Carpenter

Nebraska Center for Virology: Faculty Publications

Lentiviruses exist in vivo as a population of related, nonidentical genotypes, commonly referred to as quasispecies. The quasispecies structure is characteristic of complex adaptive systems and contributes to the high rate of evolution in lentiviruses that confounds efforts to develop effective vaccines and antiviral therapies. Here, we describe analyses of genetic data from longitudinal studies of genetic variation in a lentivirus regulatory protein, Rev, over the course of disease in ponies experimentally infected with equine infectious anemia virus. As observed with other lentivirus data, the Rev variants exhibited a quasispecies character. Phylogenetic and partition analyses suggested that the Rev quasispecies …

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Comparison Of Double Disc And Combined Disc Method For The Detection Of Extended Spectrum Beta Lactamases In Enterobacteriaceae, K Jabeen, A Zafar, Rumina Hasan Nov 2003

Comparison Of Double Disc And Combined Disc Method For The Detection Of Extended Spectrum Beta Lactamases In Enterobacteriaceae, K Jabeen, A Zafar, Rumina Hasan

Department of Pathology and Laboratory Medicine

Objective:
/="/">To compare double disc approximation and combined disc method for their ability to detect extended spectrum b lactamase (ESBL) production in enterobacteriaceae and determine the percentage of isolates which are falsely reported as sensitive in absence of ESBL detection, in a clinical microbiology laboratory of a tertiary care hospital between September-October 2002.
/="/">Methods:
/="/">Selected isolates were identified according to standard biochemical tests. Disc susceptibility tests were performed according to NCCLS. ESBL detection by combined disc [cefotaxime (30 ug) versus cefotaxime plus clavulanate (30+10 ug)] was compared with detection using double discs [amoxy-clavulanic acid (20+10 ug) and …

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Single-Cell Enumeration Of An Uncultivated Tm7 Subgroup In The, Cleber C. Ouverney, Gary C. Armitage, David A. Relman Oct 2003

Single-Cell Enumeration Of An Uncultivated Tm7 Subgroup In The, Cleber C. Ouverney, Gary C. Armitage, David A. Relman

Faculty Publications, Biological Sciences

Specific oligonucleotide hybridization conditions were established for single-cell enumeration of uncultivated TM7 and IO25 bacteria by using clones expressing heterologous 16S rRNA. In situ analysis of human subgingival crevice specimens revealed that a greater proportion of samples from sites of chronic periodontitis than from healthy sites contained TM7 subgroup IO25. In addition, IO25 bacterial cells from periodontitis site samples were more abundant and fourfold longer than IO25 cells from healthy site samples.

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Tomographic Reconstruction Of Treponemal Cytoplasmic Filaments Reveals Novel Bridging And Anchoring Components, Jacques Izard, Bruce F. Mcewen, Rita M. Barnard, Thomas Portuese, William A. Samsonoff, Ronald J. Limberger Oct 2003

Tomographic Reconstruction Of Treponemal Cytoplasmic Filaments Reveals Novel Bridging And Anchoring Components, Jacques Izard, Bruce F. Mcewen, Rita M. Barnard, Thomas Portuese, William A. Samsonoff, Ronald J. Limberger

Department of Food Science and Technology: Faculty Publications

An understanding of the involvement of bacterial cytoplasmic filaments in cell division requires the elucidation of the structural organization of those filamentous structures. Treponemal cytoplasmic filaments are composed of one protein, CfpA, and have been demonstrated to be involved in cell division. In this study, we used electron tomography to show that the filaments are part of a complex with a novel molecular organization that includes at least two distinct features decorating the filaments. One set of components appears to anchor the filaments to the cytoplasmic membrane. The other set of components appears to bridge the cytoplasmic filaments on the …

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Genome Of Bovine Herpesvirus 5, Gustavo A. Delhon, M. P. Moraes, Z. Lu, C. L. Afonso, E. F. Flores, R. Weiblen, G. F. Kutish, D. L. Rock Oct 2003

Genome Of Bovine Herpesvirus 5, Gustavo A. Delhon, M. P. Moraes, Z. Lu, C. L. Afonso, E. F. Flores, R. Weiblen, G. F. Kutish, D. L. Rock

Nebraska Center for Virology: Faculty Publications

Here we present the complete genomic sequence of bovine herpesvirus 5 (BHV-5), an alphaherpesvirus responsible for fatal meningoencephalitis in cattle. The 138,390-bp genome encodes 70 putative proteins and resembles the α2 subgroup of herpesviruses in genomic organization and gene content. BHV-5 is very similar to BHV-1, the etiological agent of infectious bovine rhinotracheitis, as reflected by the high level of amino acid identity in their protein repertoires (average, 82%). The highest similarity to BHV-1 products (≥95% amino acid identity) is found in proteins involved in viral DNA replication and processing (UL5, UL15, UL29, and UL39) and in virion proteins (UL14, …

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Morph-Dependent Fatty Acid Oxidation In A Wing-Polymorphic Cricket: Implications For The Trade-Off Between Dispersal And Reproduction, Anthony J. Zera, Zhangwu Zhao Oct 2003

Morph-Dependent Fatty Acid Oxidation In A Wing-Polymorphic Cricket: Implications For The Trade-Off Between Dispersal And Reproduction, Anthony J. Zera, Zhangwu Zhao

Anthony Zera Publications

Although a considerable amount of information is available on the ecology and physiology of wing polymorphism, much less is known about the biochemical–genetic basis of morph specialization for dispersal versus reproduction. Previous studies have shown that the dispersing morph of the wing-polymorphic cricket, Gryllus firmus, prioritizes the accumulation of triglyceride flight fuel over ovarian growth, while the opposite occurs in the flightless morph during the first week of adulthood. In this study, we compared the in vivo rate of lipid oxidation between genetic stocks of flight-capable versus flightless morphs to determine the role of lipid catabolism in morph specialization …

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Characterization Of Spy1600 A Putative Hyaluronidase Gene In Group A Streptococci, Karin M. Berling Oct 2003

Characterization Of Spy1600 A Putative Hyaluronidase Gene In Group A Streptococci, Karin M. Berling

Biological Sciences Theses & Dissertations

Group A Streptococci (GAS), also known as Streptococcus pyogenes, can cause a variety of human diseases ranging from asymptomatic to life threatening. Exactly how a single type of organism is able to inflict such a multitude of diseases remains to be fully understood. One possibility includes the large number of secreted virulence factors expressed by the organism. The recent sequencing of three streptococcal genomes has indicated the existence of several previously unknown genes, some of which may encode possible virulence factors. Among these is Spy1600, which based on its sequence similarities has been proposed to encode a hyaluronidase, a …

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Renal Carcinoid Tumour, Z Ahmad, N Yaqoob, S Muzaffar, A S. Hussainy, S H. Hasan Oct 2003

Renal Carcinoid Tumour, Z Ahmad, N Yaqoob, S Muzaffar, A S. Hussainy, S H. Hasan

Department of Pathology and Laboratory Medicine

No abstract provided.

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Renal Teratoma: A Rare Entity, N Yaqoob, Z Ahmed, N Jafri, S Muzaffar, S H. Hasan Oct 2003

Renal Teratoma: A Rare Entity, N Yaqoob, Z Ahmed, N Jafri, S Muzaffar, S H. Hasan

Department of Pathology and Laboratory Medicine

No abstract provided.

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Cultivation Of Tropheryma Whipplei From Cerebrospinal Fluid, Matthias Maiwald, Axel Von Herbay, David N. Fredricks, Cleber C. Ouverney, Jon C. Kosek, David A. Relman Sep 2003

Cultivation Of Tropheryma Whipplei From Cerebrospinal Fluid, Matthias Maiwald, Axel Von Herbay, David N. Fredricks, Cleber C. Ouverney, Jon C. Kosek, David A. Relman

Faculty Publications, Biological Sciences

Whipple disease (WD) is a systemic disorder caused by the bacterium Tropheryma whipplei. Since the recognition of a bacterial etiology in 1961, many attempts have been made to cultivate this bacterium in vitro. It was eventually isolated, in 2000, from an infected heart valve, in coculture with human fibroblasts. Here we report the isolation of 2 new strains of T. whipplei from cerebrospinal fluid (CSF) of 2 patients with intestinal WD but no neurological signs or symptoms. One culture-positive specimen was obtained before treatment; the other was obtained 12 months after discontinuation of therapy, at a time of intestinal remission. …

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Bovine Herpes Virus Gd Protein Produced In Plants Using A Recombinant Tobacco Mosaic Virus (Tmv) Vector Possesses Authentic Antigenicity, D. M. Pérez Filgueira, P.I. Zamorano, M. G. Dominguez, O. Taboga, M. P. Del Medico Zajac, M. Puntel, S. A. Romera, Thomas Jack Morris, M. V. Borca, A. M. Sadir Sep 2003

Bovine Herpes Virus Gd Protein Produced In Plants Using A Recombinant Tobacco Mosaic Virus (Tmv) Vector Possesses Authentic Antigenicity, D. M. Pérez Filgueira, P.I. Zamorano, M. G. Dominguez, O. Taboga, M. P. Del Medico Zajac, M. Puntel, S. A. Romera, Thomas Jack Morris, M. V. Borca, A. M. Sadir

Papers in Virology

A tobacco mosaic virus (TMV)-based vector was utilized for expression of a cytosolic form of the bovine herpesvirus type 1 (BHV-1) protein glycoprotein D (gDc). Nicotiana benthamiana plants were harvested 7 days after inoculation with RNA transcripts derived from the TMV-gDc recombinant virus. Recombinant gDc protein of expected electrophoretic mobility accumulated in inoculated leaves to a concentration of about 20 μg/g of fresh leaf tissue. Oil-based vaccines were formulated with crude foliar extracts to immunize mice parentally. After a single injection, animals developed a sustained and specific response to both the isolated gD and native virus particles. Cattle vaccinated with …

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Spectrum Of Cutaneous Appendage Tumors At Aga Khan University Hospital, N Yaqoob, Z Ahmad, S Muzaffar, M S. Gill, I N. Soomro, S H. Hasan Sep 2003

Spectrum Of Cutaneous Appendage Tumors At Aga Khan University Hospital, N Yaqoob, Z Ahmad, S Muzaffar, M S. Gill, I N. Soomro, S H. Hasan

Department of Pathology and Laboratory Medicine

Objective: To determine the frequency of various types of cutaneous appendage tumors in our practice.
Method: This is a partly retrospective and partly prospective study conducted at the Department of Pathology, Histopathology Section, The Aga Khan University Hospital, Karachi between 1st January 1997 and 31st December 2001.
Results: One hundred sixty six skin appendage tumors were diagnosed during the study period. 87.3% were benign, while 12.6% were malignant. Male female ratio was almost equal. Mean age was 41.72 years. 37.34% showed eccrine differentiation, 14.45% showed apocrine differentiation and 41.56% showed pilosebaceous differentiation, 6.62% exhibited mixed differentiation. The 5 commonest tumors …

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The Virulence Activator Apha Links Quorum Sensing To Pathogenesis And Physiology In Vibrio Cholerae By Repressing The Expression Of A Penicillin Amidase Gene On The Small Chromosome, Gabriela Kovacikova, Wei Lin, Karen Skorupski Aug 2003

The Virulence Activator Apha Links Quorum Sensing To Pathogenesis And Physiology In Vibrio Cholerae By Repressing The Expression Of A Penicillin Amidase Gene On The Small Chromosome, Gabriela Kovacikova, Wei Lin, Karen Skorupski

Dartmouth Scholarship

Activation of the tcpPH promoter on the Vibrio pathogenicity island by AphA and AphB initiates the Vibrio cholerae virulence cascade and is regulated by quorum sensing through the repressive action of HapR on aphA expression. To further understand how the chromosomally encoded AphA protein activates tcpPH expression, site-directed mutagenesis was used to identify the base pairs critical for AphA binding and transcriptional activation. This analysis revealed a region of partial dyad symmetry, TATGCA-N6-TNCNNA, that is important for both of these activities. Searching the V. cholerae genome for this binding site permitted the identification of a second one upstream of a …

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Quorum Sensing In Candida Albicans: Probing Farnesol’S Mode Of Action With 40 Natural And Synthetic Farnesol Analogs, Roman Shchepin, Jacob M. Hornby, Erin Burger, Timothy Niessen, Patrick H. Dussault, Kenneth Nickerson Aug 2003

Quorum Sensing In Candida Albicans: Probing Farnesol’S Mode Of Action With 40 Natural And Synthetic Farnesol Analogs, Roman Shchepin, Jacob M. Hornby, Erin Burger, Timothy Niessen, Patrick H. Dussault, Kenneth Nickerson

Kenneth Nickerson Papers

The dimorphic fungus Candida albicans produces extracellular farnesol (3,7, 11-trimethyl-2,6,10-dodecatriene- 1-ol) which acts as a quorum-sensing molecule (QSM) to suppress filamentation. Of four possible geometric isomers of farnesol, only the E,E isomer possesses QSM activity. We tested 40 natural and synthetic analogs of farnesol for their activity in an N-acetylglucosamine-induced differentiation assay for germ tube formation (GTF). Modified structural features include the head group, chain length, presence or absence of the three double bonds, substitution of a backbone carbon by S, O, N, and Se heteroatoms, presence or absence of a 3-methyl branch, and the bulkiness of the hydrophobic …

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Isolation And Characterization Of Thermophilic, Calcium-Precipitating Bacteria Form Calcite Deposits At Yucca Mountain, Terry Ann Else, Curtis R. Pantle, Penny S. Amy, Mark P. Buttner, Amy J. Smiecinski Jul 2003

Isolation And Characterization Of Thermophilic, Calcium-Precipitating Bacteria Form Calcite Deposits At Yucca Mountain, Terry Ann Else, Curtis R. Pantle, Penny S. Amy, Mark P. Buttner, Amy J. Smiecinski

Publications (YM)

Calcite deposits, composed of a mixture of calcium carbonate and silicon dioxide, were found in fractures and small cavities within the welded tuff of Yucca Mountain. This research investigation involves determining the presence of thermophilic, calciumprecipitating bacteria within these deposits. The possible existence of thermophilic bacteria may help to resolve the issue of whether these calcite deposits formed from precipitation of dissolved calcium carbonate in rain water transported from the overlying soil environment or as a result of upwelling of geothermally-heated waters transported from below the mountain. Evidence for microbially-influenced calcite precipitation in these deposits is indicated by the presence …

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Decoupling Between Bacteria And The Surf-Zone Diatom Asterionellopsis Glacialis At Cassino Beach, Brazil, Paulo C. Abreu, Leonardo R. Rorig, Virginia Garcia, Clarisse Odebrecht, Bopaiah Biddanda Jul 2003

Decoupling Between Bacteria And The Surf-Zone Diatom Asterionellopsis Glacialis At Cassino Beach, Brazil, Paulo C. Abreu, Leonardo R. Rorig, Virginia Garcia, Clarisse Odebrecht, Bopaiah Biddanda

Peer-reviewed scientific publications

The surf-zone diatom Asterionellopsis glacialis (Castracane) Round attains extremely high abundances (up to 109 cells l–1) and chl a concentrations (up to 1.5 mg chl a l–1), forming darkbrown patches in Cassino Beach, southern Brazil. Several lines of evidence from this study indicate a decoupling between A. glacialis and heterotrophic bacteria. For instance, despite the high abundance of diatoms, associated high levels of chl a and rates of dissolved organic carbon (DOC) production by A. glacialis, bacterial abundance at Cassino Beach was extremely low (0.03 to 0.7 × 106 cells ml–1) compared to the nearby estuarine waters, adjacent coastal waters …

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Crystal Structure Of The Sars Protein From Staphylococcus Aureus, Ronggui Li, Adhar C. Manna, Shaodong Dai, Ambrose L. Cheung, Gongyi Zhang Jul 2003

Crystal Structure Of The Sars Protein From Staphylococcus Aureus, Ronggui Li, Adhar C. Manna, Shaodong Dai, Ambrose L. Cheung, Gongyi Zhang

Dartmouth Scholarship

The expression of virulence determinants in Staphylococcus aureus is controlled by global regulatory loci (e.g., sarA and agr). One of these determinants, protein A (spa), is activated by sarS, which encodes a 250-residue DNA-binding protein. Genetic analysis indicated that the agr locus likely mediates spa repression by suppressing the transcription of sarS. Contrary to SarA and SarR, which require homodimer formation for proper function, SarS is unusual within the SarA protein family in that it contains two homologous halves, with each half sharing sequence similarity to SarA and SarR. Here we report the 2.2 Å …

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To The Editor: Reply To Sarmati, Brad P. Brayfield, John T. West, Charles D. Mitchell, Charles Wood Jul 2003

To The Editor: Reply To Sarmati, Brad P. Brayfield, John T. West, Charles D. Mitchell, Charles Wood

Nebraska Center for Virology: Faculty Publications

The letter by Sarmati et al. [1] presents data indicating that they were unable to find a significant correlation between human herpesvirus (HHV)–8 seropositivity and a history of spontaneous abortion in a group of 245 human immunodeficiency virus (HIV) type 1–seronegative women but that they did observe a correlation between high HHV-8 antibody titers (≥1:1280) and spontaneous abortion. Although it is possible that an increased risk of spontaneous abortion may be associated with active infection with HHV-8, at this point there is not enough evidence to support such an association. Given that several human herpes viruses are well-known agents of …

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Farnesol Biosynthesis In Candida Albicans: Cellular Response To Sterol Inhibition By Zaragozic Acid B, Jacob M. Hornby, Bessie W. Kebaara, Kenneth W. Nickerson Jul 2003

Farnesol Biosynthesis In Candida Albicans: Cellular Response To Sterol Inhibition By Zaragozic Acid B, Jacob M. Hornby, Bessie W. Kebaara, Kenneth W. Nickerson

Papers in Microbiology

The dimorphic fungus Candida albicans produces farnesol as a quorum-sensing molecule that regulates cellular morphology. The biosynthetic origin of farnesol has been resolved by treating these cells with zaragozic acid B, a potent inhibitor of squalene synthase in the sterol biosynthetic pathway. Treatment with zaragozic acid B leads to an eightfold increase in the amount of farnesol produced by C. albicans. Furthermore, C. albicans cell extracts contain enzymatic activity to convert [3H]farnesyl pyrophosphate to [3H]farnesol. Many common antifungal antibiotics (e.g., zaragozic acids, azoles, and allylamines) target steps in sterol biosynthesis. We suggest that the fungicidal …

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Identification Of The Nuclear Localization Signal Of Human Immunodeficiency Virus Type 2 Vpx, Michael Belshan, Lee Ratner Jun 2003

Identification Of The Nuclear Localization Signal Of Human Immunodeficiency Virus Type 2 Vpx, Michael Belshan, Lee Ratner

Nebraska Center for Virology: Faculty Publications

The Vpx protein of human immunodeficiency virus type 2 (HIV-2) is a viral accessory protein related to, but distinct from, the Vpr protein of HIV-1. Vpx is packaged into virions and, as a component of the viral preintegration complex (PIC), Vpx is required for efficient virus replication in nondividing cells. Therefore, the localization of Vpx in cells is dynamic and dependent upon discrete domains of the protein. Expressed in the absence of other viral proteins, Vpx localizes to the nucleus of cells. However, if expressed with the Gag protein of HIV-2, Vpx localizes to the plasma membrane of cells. To …

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Morphological Biosignatures And The Search For Life On Mars, Sherry L. Cady, Jack D. Farmer, John P. Grotzinger, J. William Schopf, Andrew Steele Jun 2003

Morphological Biosignatures And The Search For Life On Mars, Sherry L. Cady, Jack D. Farmer, John P. Grotzinger, J. William Schopf, Andrew Steele

Geology Faculty Publications and Presentations

This report provides a rationale for the advances in instrumentation and understanding needed to assess claims of ancient and extraterrestrial life made on the basis of morphological biosignatures. Morphological biosignatures consist of bona fide microbial fossils as well as microbially influenced sedimentary structures. To be recognized as evidence of life, microbial fossils must contain chemical and structural attributes uniquely indicative of microbial cells or cellular or extracellular processes. When combined with various research strategies, high-resolution instruments can reveal such attributes and elucidate how morphological fossils form and become altered, thereby improving the ability to recognize them in the geological record …

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Life Cycle Of A Torrenticolous Hawaiian Chironomid (Telmatogeton Torrenticola): Stream Flow And Microhabitat Effects, M. Eric Benbow, Albert J. Burky, Carl M. Way Jun 2003

Life Cycle Of A Torrenticolous Hawaiian Chironomid (Telmatogeton Torrenticola): Stream Flow And Microhabitat Effects, M. Eric Benbow, Albert J. Burky, Carl M. Way

Biology Faculty Publications

In this study we documented the instar densities and life cycle of Telmatogeton torrenticola Terry (Chironomidae : Telmatogetoninae) from Kinihapai Stream, Maui, Hawaii. Greatest larval densities of this midge are found on substrates of high velocity, shallow flows of cascades, and splash zones of waterfalls, with lower densities in riffles. In the summer of 1994 we compared the effects of two microhabitats (termed optimal and suboptimal) on inter-instar density and relative abundance. In a second year (1995), we evaluated the effect of long-term reduced stream flow on these variables only in optimal microhabitats. A significant reduction in stream flow from …

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A Novel Method To Detect Bacterial Restriction-Modification (R-M) Systems, Julie Kay Armantrout Kasarjian Jun 2003

A Novel Method To Detect Bacterial Restriction-Modification (R-M) Systems, Julie Kay Armantrout Kasarjian

Loma Linda University Electronic Theses, Dissertations & Projects

Analysis of recently sequenced microbial genomes has revealed many DNA sequences that code for previously unknown restriction endonucleases and their corresponding methyltransferases. These findings show that numerous restriction enzymes abundant in bacteria have yet to be discovered. Traditionally, restriction enzymes have been discovered by the classical restriction and modification (R-M) phenomena of bacteriophages (type I and III enzymes), or by direct enzyme assays (type II enzymes). To avoid the limitations of these traditional approaches, a quantitative R-M test based on plasmid transformation efficiency (Plasmid R-M Test) was established using DNA fragments derived from the E. coli bacteriophage lambda. This test …

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Potential Mechanisms Explaining The Antitumor Effect Of Total-Body Irradiation, Glen Michael Miller Jun 2003

Potential Mechanisms Explaining The Antitumor Effect Of Total-Body Irradiation, Glen Michael Miller

Loma Linda University Electronic Theses, Dissertations & Projects

While numerous reports have documented that radiation exposure increases the risk for malignancy and suppresses immune mechanisms, increasing evidence has suggested that low-dose total-body irradiation (TBI) may alter leukocyte composition and function leading to heightened immune responsiveness and long-term remission of certain cancers. Having observed that moderate-dose TBI produces an antitumor effect in the Lewis lung carcinoma (EEC) model, the major goal of this study was to determine whether changes in tumor growth could be correlated with radiation-induced alterations of immune system parameters. The governing hypothesis was that selective immune augmentation, i.e. upregulation of specific leukocyte subsets, is primarily responsible …

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Powdery Mildew In Wine Grapes In Western Australia, Diana Fisher, Trevor Wicks Dr May 2003

Powdery Mildew In Wine Grapes In Western Australia, Diana Fisher, Trevor Wicks Dr

Bulletins 4000 -

Powdery mildew is caused by the fungal pathogen Uncinula necator. It is the most persistent fungal problem of grapes in WA and one of the most widespread fungal diseases of grapevines in the world. It is characterised by ash-grey to white powdery growth on green tissue of the vine. If uncontrolled it can cause serious crop losses and impair wine quality.

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