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Articles 301 - 330 of 340

Full-Text Articles in Biology

Replicability And Recurrence In The Experimental Evolution Of A Group I Ribozyme, Martin M. Hanczyc, Robert L. Dorit Jul 2000

Replicability And Recurrence In The Experimental Evolution Of A Group I Ribozyme, Martin M. Hanczyc, Robert L. Dorit

Biological Sciences: Faculty Publications

In order to explore the variety of possible responses available to a ribozyme population evolving a novel phenotype, five Tetrahymena thermophila group I intron ribozyme pools were evolved in parallel for cleavage of a DNA oligonucleotide. These ribozyme populations were propagated under identical conditions and characterized when they reached apparent phenotypic plateaus; the populations that reached the highest plateau showed a near 100-fold improvement in DNA cleavage activity. A detailed characterization of the evolved response in these populations reveals at least two distinct phenotypic trajectories emerging as a result of the imposed selection. Not only do these distinct solutions exhibit …

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Molecular Evolution Of Odorant-Binding Protein Genes Os-E And Os-F In Drosophila, Daria S. Hekmat-Scafe, Robert L. Dorit, John R. Carlson May 2000

Molecular Evolution Of Odorant-Binding Protein Genes Os-E And Os-F In Drosophila, Daria S. Hekmat-Scafe, Robert L. Dorit, John R. Carlson

Biological Sciences: Faculty Publications

The Drosophila olfactory genes OS-E and OS-F are members of a family of genes that encode insect odorant-binding proteins (OBPs). OBPs are believed to transport hydrophobic odorants through the aqueous fluid within olfactory sensilla to the underlying receptor proteins. The recent discovery of a large family of olfactory receptor genes in Drosophila raises new questions about the function, diversity, regulation, and evolution of the OBP family. We have investigated the OS-E and OS-F genes in a variety of Drosophila species. These studies highlight potential regions of functional significance in the OS-E and OS-F proteins, which may include a region required …

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Identification Of Potential Vaccine And Drug Target Candidates By Expressed Sequence Tag Analysis And Immunoscreening Of Onchocerca Volvulus Larval Cdna Libraries, Michelle Lizotte-Waniewski, Wilson Tawe, David B. Guiliano, Wenhong Lu, Jing Liu, Steven A. Williams, Sara Lustigman Mar 2000

Identification Of Potential Vaccine And Drug Target Candidates By Expressed Sequence Tag Analysis And Immunoscreening Of Onchocerca Volvulus Larval Cdna Libraries, Michelle Lizotte-Waniewski, Wilson Tawe, David B. Guiliano, Wenhong Lu, Jing Liu, Steven A. Williams, Sara Lustigman

Biological Sciences: Faculty Publications

The search for appropriate vaccine candidates and drug targets against onchocerciasis has so far been confronted with several limitations due to the unavailability of biological material, appropriate molecular resources, and knowledge of the parasite biology. To identify targets for vaccine or chemotherapy development we have undertaken two approaches. First, cDNA expression libraries were constructed from life cycle stages that are critical for establishment of Onchocerca volvulus infection, the third-stage larvae (L3) and the molting L3. A gene discovery effort was then initiated by random expressed sequence tag analysis of 5,506 cDNA clones. Cluster analyses showed that many of the transcripts …

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Detection Of Dna Of Nocturnally Periodic Brugia Malayi In Night And Day Blood Samples By A Polymerase Chain Reaction-Elisa-Based Method Using An Internal Control Dna, Peter U. Fischer, Tanianwati Supali, Heri Wibowo, Insa Bonow, Steven A. Williams Jan 2000

Detection Of Dna Of Nocturnally Periodic Brugia Malayi In Night And Day Blood Samples By A Polymerase Chain Reaction-Elisa-Based Method Using An Internal Control Dna, Peter U. Fischer, Tanianwati Supali, Heri Wibowo, Insa Bonow, Steven A. Williams

Biological Sciences: Faculty Publications

An internal control was used in a polymerase chain reaction (PCR)–ELISA–based technique to detect the Hha I repeat of the filarial parasite Brugia malayi. A single microfilaria added to 200 �l of blood was reliably detected. The assay was evaluated on field samples from persons living in an area endemic for Anopheles-transmitted, nocturnally periodic B. malayi in central Sulawesi, Indonesia. Examination of night blood of 138 individuals for the presence of microfilariae by filtration revealed 44 microfilaria carriers. All microfilaria carriers were also positive in the PCR-ELISA and, in addition, 14 more samples were proven to contain parasite DNA. The …

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Application Of A Polymerase Chain Reaction-Elisa To Detect Wuchereria Bancrofti In Pools Of Wild-Caught Anopheles Punctualatus In A Filariasis Control Area In Papua New Guinea, Moses J. Bockarie, Peter U. Fischer, Steven A. Williams, Peter A. Zimmerman, Lysaght Griffin, Michael P. Alpers, James W. Kazura Jan 2000

Application Of A Polymerase Chain Reaction-Elisa To Detect Wuchereria Bancrofti In Pools Of Wild-Caught Anopheles Punctualatus In A Filariasis Control Area In Papua New Guinea, Moses J. Bockarie, Peter U. Fischer, Steven A. Williams, Peter A. Zimmerman, Lysaght Griffin, Michael P. Alpers, James W. Kazura

Biological Sciences: Faculty Publications

Chemotherapy-based eradication programs are aimed at stopping transmission of Wuchereria bancroftiby its obligatory mosquito vector. This study compares one year post-treatment W. bancrofti infection rates of Anopheles punctulatus, the main vector of lymphatic filariasis in Papua New Guinea, using traditional dissection techniques and a polymerase chain reaction (PCR)-based ELISA of a parasite-specific Ssp I repeat. A total of 633 mosquitoes in 35 batches were dissected. Six batches contained W. bancrofti-infected mosquitoes, giving a minimum infection rate of 0.9%. This value was not different than the actual infection rate, which was 9 (1.4%) of 633 mosquitoes (P� 0.48). The DNA was …

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Chemiluminescent Detection Of Sequential Dna Hybridizations To High- Density, Filter-Arrayed Cdna Libraries: A Subtraction Method For Novel Gene Discovery, D. Guiliano, M. Ganatra, J. Ware, J. Parrot, J. Daub, L. Moran, H. Brennecke, J. M. Foster, T. Supali, M. Blaxter, A. L. Scott, Steven A. Williams, B. E. Slatko Jan 1999

Chemiluminescent Detection Of Sequential Dna Hybridizations To High- Density, Filter-Arrayed Cdna Libraries: A Subtraction Method For Novel Gene Discovery, D. Guiliano, M. Ganatra, J. Ware, J. Parrot, J. Daub, L. Moran, H. Brennecke, J. M. Foster, T. Supali, M. Blaxter, A. L. Scott, Steven A. Williams, B. E. Slatko

Biological Sciences: Faculty Publications

A chemiluminescent approach for sequential DNA hybridizations to high- density filter arrays of cDNAs, using a biotin-based random priming method followed by a streptavidin/alkaline phosphatase/CDP-Star(TM) detection protocol, is presented. The method has been applied to the Brugia malayi genome project, wherein cDNA libraries, cosmid and bacterial artificial chromosome (BAC) libraries have been gridded at high density onto nylon filters for subsequent analysis by hybridization. Individual probes and pools of rRNA probes, ribosomal protein probes and expressed sequence tag probes show correct specificity and high signal-to-noise ratios even after ten rounds of hybridization, detection, stripping of the probes from the membranes …

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Parasitic Helminth Genomics, M. Blaxter, M. Aslett, D. Guiliano, J. Daub, Steven A. Williams, Kunthala Jayaraman, Reda Ramzy, Alan Scott, Tania Supali, Barton Slatko Jan 1999

Parasitic Helminth Genomics, M. Blaxter, M. Aslett, D. Guiliano, J. Daub, Steven A. Williams, Kunthala Jayaraman, Reda Ramzy, Alan Scott, Tania Supali, Barton Slatko

Biological Sciences: Faculty Publications

The initiation of genome projects on helminths of medical importance promises to yield new drug targets and vaccine candidates in unprecedented numbers. In order to exploit this emerging data it is essential that the user community is aware of the scope and quality of data available, and that the genome projects provide analyses of the raw data to highlight potential genes of interest. Core bioinformatics support for the parasite genome projects has promoted these approaches. In the Brugia genome project, a combination of expressed sequence tag sequencing from multiple cDNA libraries representing the complete filarial nematode lifecycle, and comparative analysis …

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Search For Exchange-Antisymmetric Two-Photon States, D. De Mille, D. Budker, N. Derr, E. Deveney Jan 1999

Search For Exchange-Antisymmetric Two-Photon States, D. De Mille, D. Budker, N. Derr, E. Deveney

Biological Sciences: Faculty Publications

Atomic two-photon J = 0 ↔ J′ = 1 transitions are forbidden for photons of the same energy. This selection rule is related to the fact that photons obey Bose-Einstein statistics. We have searched for small violations of this selection rule by studying transitions in atomic Ba. We set a limit on the probability v that photons are in exchange-antisymmetric states: v < 1.2 × 10-7.

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Ecological Effects Of Major Storms On Coastal Watersheds And Coastal Waters: Hurricane Bob On Cape Cod, I. Valiela, P. Peckol, C. D'Avanzo, J. Kremer, D. Hersh, K. Foreman, K. Lajtha, B. Seely, W. R. Geyer, T. Isaji, R. Crawford Dec 1998

Ecological Effects Of Major Storms On Coastal Watersheds And Coastal Waters: Hurricane Bob On Cape Cod, I. Valiela, P. Peckol, C. D'Avanzo, J. Kremer, D. Hersh, K. Foreman, K. Lajtha, B. Seely, W. R. Geyer, T. Isaji, R. Crawford

Biological Sciences: Faculty Publications

Hurricane Bob, a category 3 storm, made landfall on Cape Cod in August 1991, and its effects on watersheds and adjoining estuaries were detected in the ongoing studies being caried out as part of the Waquoit Bay Land Margin Ecosystems Research project. On land, Bob had only minor overall effects on forests; localized wind bursts did snap and break trees in small and widely scattered forest parcels. Wind stripped up to half the leaves of deciduous trees and many herbaceous plants on the watershed, and most remaining leaves were damaged by salt, so that by the end of Aug, Cape …

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Thermoregulation Of Escherichia Coil Pap Transcription: H-Ns Is A Temperature-Dependent Dna Methylation Blocking Factor, Christine A. White-Ziegler, Melinda L. Angus Hill, Bruce A. Braaten, Marjan W. Van Der Woude, David A. Low Jul 1998

Thermoregulation Of Escherichia Coil Pap Transcription: H-Ns Is A Temperature-Dependent Dna Methylation Blocking Factor, Christine A. White-Ziegler, Melinda L. Angus Hill, Bruce A. Braaten, Marjan W. Van Der Woude, David A. Low

Biological Sciences: Faculty Publications

The expression of Pap pili that facilitate the attach- ment of Escherichia coli to uroepithelial cells is shut off outside the host at temperatures below 268C. Ribo- nuclease protection analysis showed that this thermo- regulatory response was rapid as evidenced by the absence of papBA transcripts, coding for Pap pilin, after only one generation of growth at 238C. The his- tone-like nucleoid structuring protein H-NS and DNA sequences within papB were required for thermoregu- lation, but the PapB and PapI regulatory proteins were not. In vivo analysis of pap DNA methylation patterns indicated that H-NS or a factor regulated by …

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The Immunodominant Brugia Malayi Paramyosin As A Marker Of Current Infection With Wuchereria Bancrofti Adult Worms, Sandra Langy, Catherine Plichart, Patrick Luquiaud, Steven A. Williams, Luc Nicolas Jun 1998

The Immunodominant Brugia Malayi Paramyosin As A Marker Of Current Infection With Wuchereria Bancrofti Adult Worms, Sandra Langy, Catherine Plichart, Patrick Luquiaud, Steven A. Williams, Luc Nicolas

Biological Sciences: Faculty Publications

The full-length cDNA sequence encoding Brugia malayi L3 paramyosin has been isolated by immunoscreening a cDNA library with a mouse antiserum raised against Wuchereria bancrofti L3 infective larvae. A recombinant truncated form of paramyosin was expressed as a glutathione S-transferase fusion protein and used to evaluate humoral responses of adults from a W. bancrofti-endemic area in French Polynesia according to their parasitological status. Immunoglobulin G4 (IgG4) preferentially bound to paramyosin in W. bancrofti-parasitized individuals, in contrast to unparasitized individuals, who harbored neither microfilaria nor Og4C3 adult worm circulating antigen. Reduction of the anti-paramyosin IgG4 titer following combined chemotherapy with diethylcarbamazine …

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Immunochemical And Immunocytochemical Identification Of A Myosin Heavy Chain Polypeptide In Nicotiana Pollen Tubes, X. J. Tang, P. K. Hepler, Stylianos P. Scordilis Apr 1998

Immunochemical And Immunocytochemical Identification Of A Myosin Heavy Chain Polypeptide In Nicotiana Pollen Tubes, X. J. Tang, P. K. Hepler, Stylianos P. Scordilis

Biological Sciences: Faculty Publications

A myosin heavy chain polypeptide has been identified and localized in Nicotiana pollen tubes using monoclonal anti-myosin antibodies. The epitopes of these antibodies were found to reside on the myosin heavy chain head and rod portion and were, therefore, designated anti-S-1 (myosin S-1) and anti-LMM (light meromyosin). On Western blots of the total soluble pollen tube proteins, both anti-S-1 and anti-LMM label a polypeptide of approximately 175,000 Mr. Immunofluorescence microscopy shows that both antibodies yield numerous fluorescent spots throughout the whole length of the tube, often with an enrichment in the tube tip. These fluorescent spots are thought to represent …

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Experimental Evolution Of Complexity: In Vitro Emergence Of Intermolecular Ribozyme Interactions, Martin M. Hanczyc, Robert L. Dorit Mar 1998

Experimental Evolution Of Complexity: In Vitro Emergence Of Intermolecular Ribozyme Interactions, Martin M. Hanczyc, Robert L. Dorit

Biological Sciences: Faculty Publications

In the course of evolving variants of the Tetrahymena thermophila Group I ribozyme for improved DNA cleavage in vitro, we witnessed the unexpected emergence of a derived molecular species, capable of acting as a partner for the ribozyme, but no longer autocatalytic. This new RNA species exhibits a deletion in the catalytic core and participates in a productive intermolecular interaction with an active ribozyme, thus insuring its survival in the population. These novel RNA molecules have evolved a precise catalytic interaction with the Group I ribozyme and depend for their survival on the continued presence of active catalysts. This interaction …

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Detection Of The Filarial Parasite Mansonella Streptocerca In Skin Biopsies By A Nested Polymerase Chain Reaction-Based Assay, Peter U. Fischer, Dietrich W. Büttner, Jotham Bamuhiiga, Steven A. Williams Jan 1998

Detection Of The Filarial Parasite Mansonella Streptocerca In Skin Biopsies By A Nested Polymerase Chain Reaction-Based Assay, Peter U. Fischer, Dietrich W. Büttner, Jotham Bamuhiiga, Steven A. Williams

Biological Sciences: Faculty Publications

To differentiate the skin-dwelling filariae Mansonella streptocerca and Onchocerca volvulus, a nested polymerase chain reaction (PCR) assay was developed from small amounts of parasite material present in skin biopsies. One nonspecific and one specific pair of primers were used to amplify the 5S rDNA spacer region of M. streptocerca. Biopsies with different microfilaria densities obtained from 104 Ugandans living in an area endemic forM. streptocerca were tested using both the nested PCR assay and standard parasitologic assessment of microfilariae. All 82 samples from microfilaria carriers were positive when tested using the nested PCR assay. In addition, M. streptocerca DNA could …

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Effect Of Transatlantic Transport On Reproduction Of Agouti And Nonagouti Deer Mice, Peromyscus Maniculatus, Virginia Hayssen Jan 1998

Effect Of Transatlantic Transport On Reproduction Of Agouti And Nonagouti Deer Mice, Peromyscus Maniculatus, Virginia Hayssen

Biological Sciences: Faculty Publications

In conjunction with establishing colonies of deer mice in the UK, effects of transportation on reproduction in agouti (A) and nonagouti (a) deer mice were assessed. Adults were shipped via ground courier and air freight from Northampton, Massachusetts, USA to Sutton Bonington, Leicestershire, England in February and June. Deer mice were paired upon arrival in Sutton Bonington, whereas matched controls were paired in the original colonies at shipping. To assess reproduction, the following variables were monitored for 110 days for all 96 pairs: number of pairs producing litters, time from pairing to birth, interlitter interval, litter size at birth, and …

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Nodule Organogenesis And Symbiotic Mutants Of The Model Legume Lotus Japonicus, Krzysztof Szczyglowski, Robert S. Shaw, Judith Wopereis, Sue Copeland, Dirk Hamburger, Beth Kasiborski, Frank B. Dazzo, Frans J. De Bruijn Jan 1998

Nodule Organogenesis And Symbiotic Mutants Of The Model Legume Lotus Japonicus, Krzysztof Szczyglowski, Robert S. Shaw, Judith Wopereis, Sue Copeland, Dirk Hamburger, Beth Kasiborski, Frank B. Dazzo, Frans J. De Bruijn

Biological Sciences: Faculty Publications

A detailed microscopical analysis of the morphological features that distinguish different developmental stages of nodule organogenesis in wild-type Lotus japonicus ecotype Gifu B-129-S9 plants was performed, to provide the necessary framework for the evaluation of altered phenotypes of L. japonicus symbiotic mutants. Subsequently, chemical ethyl methanesulfonate (EMS) mutagenesis of L. japonicus was carried out. The analysis of approximately 3,000 M1 plants and their progeny yielded 20 stable L. japonicus symbiotic variants, consisting of at least 14 different symbiosis- associated loci or complementation groups. Moreover, a mutation affecting L. japonicus root development was identified that also conferred a hypernodulation response when …

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Interactive Effects Of Inducible Defense And Resource Availability On Phlorotannins In The North Atlantic Brown Alga Fucus Vesiculosus, P. Peckol, J. M. Krane, J. L. Yates Jul 1996

Interactive Effects Of Inducible Defense And Resource Availability On Phlorotannins In The North Atlantic Brown Alga Fucus Vesiculosus, P. Peckol, J. M. Krane, J. L. Yates

Biological Sciences: Faculty Publications

Research seeking to explain the ecological role of polyphenolics (phlorotannins) in plants and brown algae has largely focused on 2 alternative concepts, the carbon/nutrient (C/N) balance and the inducible defense models. We tested the hierarchy of effects of both models on phlorotannin production in the brown alga Fucus vesiculosus (Fucales) by simultaneously manipulating the N environment and simulating herbivory for 2 oceanic (high and low intertidal) and estuarine populations. We measured phlorotannin levels in algae under control, grazed, N-enriched, and grazed + N-enriched treatments with time (0 to 14 d) throughout the year to determine onset and duration of the …

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Allometry Of Litter Mass In Bats: Maternal Size, Wing Morphology, And Phylogeny, Virginia Hayssen, T. H. Kunz Jan 1996

Allometry Of Litter Mass In Bats: Maternal Size, Wing Morphology, And Phylogeny, Virginia Hayssen, T. H. Kunz

Biological Sciences: Faculty Publications

We examine how litter mass in bats varies with respect to wing loading, an important aerodynamic aspect of flight. From geometric proportions, litter mass should scale to wing loading by an exponent of three. Conversely, analysis of aerodynamic consequences of carrying extra mass suggests that an exponent significantly less than three would be selectively advantageous. Our results show that Megachiroptera and Microchiroptera differ in the relationship between litter mass and wing loading. Litter mass in megachiropterans scales as expected by geometric proportions, whereas litter mass in microchiropterans, as a group, and for individual families, scales as expected if aerodynamic consequences …

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A Pcr Assay For The Detection Of Wuchereria Bancrofti In Blood, Min Zhong, James Mccarthy, Lou Ann Bierwert, Michelle Lizotte-Waniewski, Suzanne Chanteau, Thomas Nutman, Eric A. Ottesen, Steven A. Williams Jan 1996

A Pcr Assay For The Detection Of Wuchereria Bancrofti In Blood, Min Zhong, James Mccarthy, Lou Ann Bierwert, Michelle Lizotte-Waniewski, Suzanne Chanteau, Thomas Nutman, Eric A. Ottesen, Steven A. Williams

Biological Sciences: Faculty Publications

To identify Wuchereria bancrofti DNA sequences that could be used as the basis for a simple and rapid parasite detection assay, a genomic library of W. bancrofti was constructed and screened for highly repeated DNA. The repeat found with the highest copy number was 195 basepairs (bps) long, 77% AT, and 300 copies per haploid genome. This sequence was designated the Ssp I repeat because it has a unique recognition site for that restriction endonuclease in all or most of the repeat copies. The Ssp I repeat DNA family is dispersed, genus-specific, and exists in all of the different geographic …

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Identification And Localization Of Three Classes Of Myosins In Pollen Tubes Of Lilium Longiflorum And Nicotiana Alata, D. D. Miller, Stylianos P. Scordilis, P. K. Hepler Jul 1995

Identification And Localization Of Three Classes Of Myosins In Pollen Tubes Of Lilium Longiflorum And Nicotiana Alata, D. D. Miller, Stylianos P. Scordilis, P. K. Hepler

Biological Sciences: Faculty Publications

The presence and localization of actin and myosin have been examined in pollen tubes of Lilium longiflorum and Nicotiana alata. Immunoblot analysis of pollen tube extracts with antibodies to actin, myosins IA and IB, myosin II, and myosin V reveals the presence of these contractile proteins. Immunofluorescence microscopy using various methods to preserve the pollen tubes; chemical fixation, rapid freeze fixation and freeze substitution (RF-FS) followed by rehydration or by embeddment in a methacrylate mixture, was performed to optimize preservation. Immunocytochemistry reaffirmed that actin is localized longitudinally in the active streaming lanes and near the cortical surface of the …

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Molecular Phylogenetic Studies Of The Genus Brugia, Hong Xie, O. Bain, Steven A. Williams Jan 1994

Molecular Phylogenetic Studies Of The Genus Brugia, Hong Xie, O. Bain, Steven A. Williams

Biological Sciences: Faculty Publications

This paper is the first molecular phylogenetic study on Brugia para- sites (family Onchocercidae) which includes 6 of the 10 species of this genus : B. beaveri Ash et Little, 1 9 6 4 ; B. buckleyiDissanaike et Paramananthan, 1961 ; B. malayi (Brug,1927) Buckley, 1960 ; B. pohangi, (Buckley et Edeson, 1956) Buckley, 1960; B. patei (Buckley, Nelson etHeisch,1958) Buckley, 1960 and B. limori Partono et al., 1 9 7 7 . Hha I repeat sequences are 322 nucleotides long, highly repeated, tandemly arranged and unique to the nuclear genomes of the genus Brugia. Hha I repeat sequence data …

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Molecular Phylogenetic Studies On Filarial Parasites Based On 5s Ribosomal Spacer Sequences, Hong Xie, O. Bain, Steven A. Williams Jan 1994

Molecular Phylogenetic Studies On Filarial Parasites Based On 5s Ribosomal Spacer Sequences, Hong Xie, O. Bain, Steven A. Williams

Biological Sciences: Faculty Publications

This paper is the first large-scale molecular phylogenetic study on filarial parasites (family Onchocercidae) which includes 16 spe­ cies of 6 genera : Brugia beaveri Ash et Little, 1964 ; B. buckleyiDissanaike et Paramananthan, 1961 ; B. malayi (Brug, 1927) Buckley, 1960; B. pahangi (Buckley et Edeson, 1956) Buckley, 1960; B. patei (Buckley, Nelson et Heisch, 1958) Buckley, 1960; B. timori Partono etal, 1977; Wuchereria bancrofti(Cobbold, 1877) Seurat, 1921; W. kalimantani Palmieri , Purnomo, Dennis and Marwoto, 1980; Mansonella perstans(Manson, 1891 ) Eberhard et Orihel, 1 9 8 4 ; Loa loa, Stiles, 1905; Onchocerca volvulus (Leuckart, 1983) Railliet et …

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Thermoregulation Of The Pap Operon: Evidence For The Involvement Of Rimj, The N-Terminal Acetylase Of Ribosomal Protein S5, C. A. White-Ziegler, D. A. Low Jan 1992

Thermoregulation Of The Pap Operon: Evidence For The Involvement Of Rimj, The N-Terminal Acetylase Of Ribosomal Protein S5, C. A. White-Ziegler, D. A. Low

Biological Sciences: Faculty Publications

Our previous work showed that pap pilin gene transcription is subject to a thermoregulatory control mechanism under which pap pilin is not transcribed at a low temperature (23°C) (L. B. Blyn, B. A. Braaten, C. A. White-Ziegler, D. H. Rolfson, and D. A. Low, EMBO J. 8:613-620, 1989). In order to isolate genes involved in this temperature regulation of gene expression, chromosomal mini-TnlO (mTnlO) mutations that allowed transcription of the pap pilin gene at 23°C were identified, and the locus was designated tcp, for "thermoregulatory control of pap" (C. A. White-Ziegler, L. B. Blyn, B. A. Braaten, and D. A. …

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A Proline-Rich Structural Protein Of The Surface Sheath Of Larval Brugia Filarial Nematode Parasites, Murray E. Selkirk, Maria Yazdanbakhsh, Danie Freedman, Mark L. Blaxter, Edith Cookson, Rosalind E. Jenkins, Steven A. Williams Jun 1991

A Proline-Rich Structural Protein Of The Surface Sheath Of Larval Brugia Filarial Nematode Parasites, Murray E. Selkirk, Maria Yazdanbakhsh, Danie Freedman, Mark L. Blaxter, Edith Cookson, Rosalind E. Jenkins, Steven A. Williams

Biological Sciences: Faculty Publications

Both cDNA and genomic DNA sequences have been isolated which encode a proline-rich precursor protein of the sheath from microfilariae, the first stage larvae of the filarial nematode parasites Brugia pahangi andBrugia malayi. This 22-kDa protein is soluble only under reducing conditions and is extensively cross- linked by both disulfide and nonreducible bonds. Immunogold electron microscopy shows that the protein is localized exclusively in the sheath, a vestigial remnant of the eggshell, which is retained by and encloses the mature microfilaria. Analysis by Western blotting confirms that the protein is expressed only in microfilariae and adult female worms, although transcripts …

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Identification Of An Escherichia Coli Genetic Locus Involved In Thermoregulation Of The Pap Operon, C. A. White-Ziegler, L. B. Blyn, B. A. Braaten, D. A. Low Jan 1990

Identification Of An Escherichia Coli Genetic Locus Involved In Thermoregulation Of The Pap Operon, C. A. White-Ziegler, L. B. Blyn, B. A. Braaten, D. A. Low

Biological Sciences: Faculty Publications

We previously showed, using a single-copy papBAp-lac fusion (previously designated papBA-lac), that pyelonephritis-associated pili (pap) pilin gene transcription is subject to both phase variation and thermoreg- ulatory control mechanisms (L. B. Blyn, B. A. Braaten, C. A. White-Ziegler, D. H. Rolfson, and D. A. Low, EMBO J. 8:613-620, 1989). At 37°C, Escherichia coli strains carrying the papBAp-lac fusion displayed both Lac' and Lac- colony phenotypes. In contrast, at 23°C, colonies displayed a uniform Lac- phenotype, suggesting that pilin was not transcribed at this temperature. In this study, a strain carrying the papBAp-lac fusion was subjected to mini-TnlO (mTnlO) mutagenesis to …

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Direct Genomic Sequencing Of Bacterial Dna: The Pyruvate Kinase I Gene Of Escherichia Coli, Osamu Ohara, Robert L. Dorit, Walter Gilbert Sep 1989

Direct Genomic Sequencing Of Bacterial Dna: The Pyruvate Kinase I Gene Of Escherichia Coli, Osamu Ohara, Robert L. Dorit, Walter Gilbert

Biological Sciences: Faculty Publications

The genomic sequencing procedure is applied to the direct sequencing of uncharacterized regions of bacterial DNA by a "multiplex walking" approach. Samples of bulk Escherichia coli DNA are cut with various restriction enzymes, subjected to chemical sequencing degradations, run in a sequencing gel, and transferred to nylon membranes. When a labeled oligomer is hybridized to a membrane, a sequence ladder appears wherever the probe lies near a restriction cut. New probes, based on sequence that lies beyond other restriction sites, are then synthesized, and the membranes are reprobed to reveal new sequence. Repeated cycles of oligomer probe synthesis and subsequent …

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One-Sided Polymerase Chain Reaction: The Amplification Of Cdna, Osamu Ohara, Robert L. Dorit, Walter Gilbert Aug 1989

One-Sided Polymerase Chain Reaction: The Amplification Of Cdna, Osamu Ohara, Robert L. Dorit, Walter Gilbert

Biological Sciences: Faculty Publications

We report a rapid technique, based on the polymerase chain reaction (PCR), for the direct targeting, enhancement, and sequencing of previously uncharacterized cDNAs. This method is not limited to previously sequenced transcripts, since it requires only two adjacent or partially overlapping specific primers from only one side of the region to be amplified. These primers can be located anywhere within the message. The specific primers are used in conjunction with nonspecific primers targeted either to the poly(A)+ region of the message or to an enzymatically synthesized d( A) tail. Pairwise combinations of specific and general primers allow for the amplification …

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A Field Study Using The Polymerase Chain Reaction (Pcr) To Screen For Brugia Microfilariae In Human And Animal Blood, Janet Glover, Steven A. Williams, Susanne Szabo, David Landry, Larry A. Mcreynolds, Taniawati Supali, Felix Partono Jan 1989

A Field Study Using The Polymerase Chain Reaction (Pcr) To Screen For Brugia Microfilariae In Human And Animal Blood, Janet Glover, Steven A. Williams, Susanne Szabo, David Landry, Larry A. Mcreynolds, Taniawati Supali, Felix Partono

Biological Sciences: Faculty Publications

Blood samples from 43 humans and 14 cats with Brugia microfilariae were analyzed in a field study in Tanjung Pinang, Indonesia. The study used the polymerase chain reaction (PCR) to compare the sensitivity of radioactive and biotinylated species-specific oligonuleotide probes. The cloning char- acterization of the Hha I repeat DNA family found in filarial parasites of the genus Brugia, and the development of species-specific probes for B.malayi and B.pahangi based on these repeats has been described elsewhere (PNAS USA 83: 797-801); Mol.Biochem. Parasitol. 28: 163-170). The use of radioisotopes for labelling DNA probes is both expensive and inconvenient. To replace …

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Phase-Variation Of Pyelonephritis-Associated Pili In Escherichia Coli: Evidence For Transcriptional Regulation, L. B. Blyn, B. A. Braaten, C. A. White-Ziegler, D. H. Rolfson, D. A. Low Jan 1989

Phase-Variation Of Pyelonephritis-Associated Pili In Escherichia Coli: Evidence For Transcriptional Regulation, L. B. Blyn, B. A. Braaten, C. A. White-Ziegler, D. H. Rolfson, D. A. Low

Biological Sciences: Faculty Publications

The regulation of pyelonephritis-associated pill (pap) pflin gene transcription has been examined using two operons (pap-17 and pap-21) isolated from the pyelonephritogenic Escherichia coli strain C1212. DNA sequence analysis and E.coli minicell analysis were used to map two genes (papB and papl) within the pilin regulatory regions of both pap-17 and pap-21, and the protein products of these genes were identified. Pilin transcription, initiated at the papBA promoter, was monitored by constructing single copy operon fusions with lacZYA in E.coli K-12. Inocula- tion of E.coli (pap'-lac) strains onto solid M9 minimal medium containing glycerol and the Lac indicator X-gal (M9-Glycerol) …

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The Control Of Myocardial Contraction With Skeletal Fast Muscle Troponin C., A. Babu, Stylianos P. Scordilis, E. H. Sonnenblick, J. Gulati Apr 1987

The Control Of Myocardial Contraction With Skeletal Fast Muscle Troponin C., A. Babu, Stylianos P. Scordilis, E. H. Sonnenblick, J. Gulati

Biological Sciences: Faculty Publications

The present study describes experiments on the myocardial trabeculae from the right ventricle of Syrian hamsters whose troponin C (TnC) moiety was exchanged with heterologous TnC from fast skeletal muscle of the rabbit. These experiments were designed to help define the role of the various classes of Ca2+-binding sites on TnC in setting the characteristic sensitivities for activations of cardiac and skeletal muscles. Thin trabeculae were skinned and about 75% of their troponin C extracted by chemical treatment. Tension development on activations by Ca2+ and Sr2+ was found to be nearly fully blocked in such TnC extracted preparations. Troponin C …

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