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External Morphology Of The Chorion Of The Annual Fishes Cynolebias (Cyprinodontiformes: Rivulidae), Marcelo Loureiro, Rafael O. De Sá

Biology Faculty Publications

Members of the family Rivulidae (killifishes) inhabit temporary bodies of freshwater in South and Central America (one species is also found in North America). The most remarkable characteristic of the family Rivulidae is that species have an annual life cycle with a drought-resistant egg during the dry season. Parenti's (1981) analysis of the order Cyprinodontiformes considered a single genus, Cynolebias, whereas Cos- ta's (1990) phylogenetic analysis of the family Rivulidae separates Cynolebias from Cynopoecilus. One of Costa's synapomorphies to separate Cynopoecilus is the unique structure of their egg's chorion, which is shared with Leptolebias and Campellolebias.

Discord Between The Phylogenies Inferred From Molecular Versus Functional Data: Uneven Rates Of Functional Evolution Or Low Levels Of Gene Flow?, Michael F. Palopoli, Andrew W. Davis, Chung I. Wu

Biology Faculty Publications

According to measures of molecular divergence, the three species of the Drosophila simulans clade are closely related to and essentially equidistant from each other. We introgressed 10% of the D. sechellia X chromosome into a pure D. simulans genetic background and found that males carrying this introgressed region were consistently fertile; in contrast, males carrying the same segment from D. mauritiana are sterile and suffer from incompatibilities at a minimum of four loci. Together with other recent results, these data suggest that D. simulans and D. sechellia are much more closely related to each other than either is to D. …

Hydrophobic Core But Not Amino-Terminal Charged Residues Are Required For Translocation Of An Integral Thylakoid Membrane Protein In Vivo, Benoit Baillet, Bruce D. Kohorn

Biology Faculty Publications

The integral membrane protein cytochrome f contains an amino-terminal signal sequence that is required for translocation into the thylakoid membrane. The signal sequence contains a hydrophobic core neighbored by an amino-terminal charged residue. Mutations that introduce charged amino acids into the hydrophobic core are inhibitory to cytochrome f translocation, and thus render cells non-photosynthetic. We have isolated both nuclear and chloroplast suppressors of these mutations by selecting for restoration of photosynthetic growth of Chlamydomonas. Here we describe the characterization of two chloroplast, second site suppressor mutations. Both suppressors remove the positively charged amino acid that borders the amino terminus of …

Rapid Evolution Of A Coadapted Gene Complex: Evidence From The Segregation Distorter (Sd) System Of Meiotic Drive In Drosophila Melanogaster, Michael F. Palopoli, Chung I. Wu

Biology Faculty Publications

Segregation Distorter (SD) is a system of meiotic drive found in natural populations of Drosophila melanogaster. Males heterozygous for an SD second chromosome and a normal homologue (SD+) produce predominantly SD- bearing sperm. The coadapted gene complex responsible for this transmission advantage spans the second chromosome centromere, consisting of three major and several minor interacting loci. To investigate the evolutionary history of this system, we surveyed levels of polymorphism and divergence at six genes that together encompass this pericentromeric region and span seven map units. Interestingly, there was no discernible divergence between SD and SD1 chromosomes for any of these …

A Cell Wall-Associated, Receptor-Like Protein Kinase, Zheng Hui He, Masaaki Fujiki, Bruce D. Kohorn

Biology Faculty Publications

Physical connections between higher plant cell walls and the plasma membrane have been identified visually, but the molecules involved in the contact are unknown. We describe here an Arabidopsis thaliana protein kinase, designated Wak1 for wall-associated kinase, whose predicted extracytoplasmic domain contains several epidermal growth factor repeats and identity with a viral movement protein. Wak1 fractionates with insoluble material when plant tissue is ground in a variety of buffers and detergents, suggesting a tight association with the plant extracellular matrix. Immunocytochemistry confirms that Wak1 is associated with the cell wall. Enzymatic digestion of the cell wall allows the release of …

Taking Root, W. John Hayden

Biology Faculty Publications

The brief description of mangrove reproduction in John N. Cole's "Off Key, Out of Reach" [A Sense of Place, July-August] contains an error.

Mutagenicity Of Acridines In A Reversion Assay Based On Tetracycline Resistance In Plasmid Pbr322 In Escherichia Coli, George R. Hoffman, Suzanne M. Deschênes, Teresa Manyin, Robert P. P. Fuchs

Biology Faculty Publications

The mutagenicity of a series of acridine compounds was studied in an assay based on the reversion of mutations in the tetracycline-resistance gene (tet) of plasmid pBR322 in Escherichia coli. Mutations that restore the tetracycline-resistant phenotype were detected in tetracycline-sensitive strains carrying mutant plasmids. Mutations that revert by +2, +1, −1, and −2 frameshift mutations and by base-pair substitutions were used to analyze the mutagenicity of two simple acridines, two acridine mustards, and a nitroacridine. The simple acridines (9-aminoacridine and quinacrine) effectively induced −1 frameshifts and weakly induced +1 frameshifts. The acridine mustards (quinacrine mustard and ICR-191) …

Human Protein Sam68 Relocalization And Interaction With Poliovirus Rna Polymerase In Infected Cells, A. E. Mcbride, A. Schlegel, K. Kirkegaard

Biology Faculty Publications

A HeLa cDNA expression library was screened for human polypeptides that interacted with the poliovirus RNA-dependent RNA polymerase, 3D, using the two-hybrid system in the yeast Saccharomyces cerevisiae. Sam68 (Src- associated in mitosis, 68 kDa) emerged as the human cDNA that, when fused to a transcriptional activation domain, gave the strongest 3D interaction signal with a LexA-3D hybrid protein. 3D polymerase and Sam68 coimmunoprecipitated from infected human cell lysates with antibodies that recognized either protein. Upon poliovirus infection. Sam68 relocalized from the nucleus to the cytoplasm, where poliovirus replication occurs. Sam68 was isolated from infected cell lysates with an antibody …

Interactions Involving The Human Rna Polymerase Ii Transcription/Nucleotide Excision Repair Complex Tfiih, The Nucleotide Excision Repair Protein Xpg, And Cockayne Syndrome Group B (Csb) Protein, Narayan Iyer, Michael S. Reagan, Kou-Juey Wu, Bertram Canagarajah, Errol C. Friedberg

Biology Faculty Publications

The human basal transcription factor TFIIH plays a central role in two distinct processes. TFIIH is an obligatory component of the RNA polymerase II (RNAP II) transcription initiation complex. Additionally, it is believed to be the core structure around which some if not all the components of the nucleotide excision repair (NER) machinery assemble to constitute a nucleotide excision repairosome. At least two of the subunits of TFIIH (XPB and XPD proteins) are implicated in the disease xeroderma pigmentosum (XP). We have exploited the availability of the cloned XPB, XPD, p62, p44, and p34 genes (all …

Behavioral Basis Of Second Intermediate Host Specificity Among Four Species Of Haematoloechus (Digenea: Haematoloechidae), Scott D. Snyder, John J. Janovy Jr.

Biology Faculty Publications

Cercarial behavior patterns were examined in four species of frog lung flukes (Haematoloechus spp.). Cercariae of Haematoloechus complexus, Haematoloechus medioplexus, Haematoloechus longiplexus, and Haematoloechus varioplexus were exposed to three species of experimental arthropods and an inanimate control. The number of cercariae attached to an experimental host at 5 min postexposure was recorded. Haematoloechus longiplexus and H. complexus cercariae attached to experimental hosts at higher rates than cercariae of H. medioplexus and H. varioplexus. Cercariae of H. longiplexus attached to experimental hosts in approximately the same numbers as H. complexus, but H. longiplexus penetrated only damselfly naiads, …

Topographically Specific Effects Of Elf-1 On Retinal Axon Guidance In Vitro And Retinal Axon Mapping In Vivo, Masaru Nakamoto

Biology Faculty Publications

Topographic maps, which maintain the spatial order of neurons in the order of their axonal connections, are found throughout the nervous system. In the visual retinotectal projection, ELF-1, a ligand in the tectum, and its receptors in the retina show complementary gradients in expression and binding, indicating they may be positional labels for map development. Here we show that ELF-1 acts as a repellent axon guidance factor in vitro. In vivo, when the tectal ELF-1 pattern is modified by retroviral overexpression, retinal axons avoid ectopic ELF-1 patches and map to abnormally anterior positions. All these effects were seen on axons …

Mutations In Trans-Acting Factors Affecting Mrna Decapping In Saccharomyces Cereviciae, Lianna K. Etchberger, C. A. Stevens, A. Stevens, R. Parker

Biology Faculty Publications

The decay of several yeast mRNAs occurs by a mechanism in which deadenylation precedes decapping and subsequent 5'-to-3' exonucleolytic decay. In order to identify gene products required for this process of mRNA turnover, we screened a library of temperature-sensitive strains for mutants with altered mRNA degradation. We identified seven mutations in four genes that inhibited mRNA turnover. Two mutations were alleles of the XRN1 5'-to-3' exoribonuclease known to degrade mRNAs following decapping. One mutation defined a new gene, termed DCP1, which in subsequent work was demonstrated to encode a decapping enzyme or a necessary component of a decapping complex. The …

Fate Of Biological Control Introductions: Monitoring An Australian Fungal Pathogen Of Grasshoppers In North America, Michael J. Bidochka, Scott R. A. Walsh, Mark E. Ramos, Raymond J. St. Leger, Julie Cl Silver, Donald W. Roberts

Biology Faculty Publications

In North America there are two generally recognized pathotypes (pathotypes 1 and 2) of the fungus Entomophaga grylli which show host-preferential infection of grasshopper subfamilies. Pathotype 3, discovered in Austra- lia,hasabroadergrasshopperhostrangeandwasconsidered to be a good biocontrol agent. Between 1989 and 1991 patho- type3wasintroducedattwofieldsitesinNorthDakota.Since resting spores are morphologically indistinguishable among pathotypes, we used pathotype-specific DNA probes to con- firm pathotype identification in E. grylli-infected grasshop- pers collected at the release sites in 1992, 1993, and 1994. In 1992, up to 23% of E. grylli-infected grasshoppers of the subfamilies Melanoplinae, Oedipodinae, and Gomphocerinae were infected by pathotype 3,with no infections >1 km …

A Revision Of Discocarpus (Euphorbiaceae), Sheila M. Hayden, W. John Hayden

Biology Faculty Publications

As revised here, Discocarpus is interpreted to consist of three neotropical species: D. essequeboensis Klotzsch, D. gentryi S. M. Hayden, which is described and named herein as new to science, and D. spruceanus Müll. Arg. One previously accepted name, D. brasiliensis Klotzsch ex Müll. Arg., is reduced to synonymy of D. essequeboensis. Lecto-types are proposed for the two species previously described. One species is newly excluded from Discocarpus, as are three others, following previous literature. Foliar anatomy is described with a focus on epidermal sclereids, which are shown to occur on both epidermides. Evidence presented supports close relationships …

Hyla Multifasciata, Rafael O. De Sá

Biology Faculty Publications

Hyla multifasciata is a medium to large species in the albopunctata species group, adults ranging in size from 42 - 61 mm SVL (mean male SVL = 48 mm, mean female SVL = 53 mm). The head is longer than wide. The snout is rounded in dorsal view, whereas in lateral view it is rounded and protrudes slightly beyond the mandible. The canthus rostralis is rounded and distinct, the loreal region is concave, and the internarial region is convex. The eyes are large, approximately twice the diameter of the tympanum. The tympanum is separated from the eye by a distance …

Leptodactylus Silvanimbus (Amphibia: Anura: Leptodactylidae): Natural History Notes, Advertisement Call, And Relationships, W. Ronald Heyer, Rafael O. De Sá, James R. Mccranie, Larry David Wilson

Biology Faculty Publications

In July 1995, we visited two of the three previously known localities for Leprodactylus silvanimbus in Departamento de Ocotepeque, Honduras. We found a new breeding site for the species, recorded its advertisement call, and collected and observed its adults and larvae. The purpose of this paper is to present the results of these new findings and to comment on the relationships L. silvanimbus.

Características De La Osificación Craneal En Phyllomedusa Boliviana (Anura: Hylidae), Rafael O. De Sá, E. O. Lavilla

Biology Faculty Publications

RESUMEN. Dentro de la familia Hylidae disponemos de información sobre las secuencias de osificación craneal para menos del 4.0% de sus miembros. El presente trabajo describe la secuencia de osificación craneal de Phyllomedusa boliviana. El patrón general de osificación es similar a lo reportado para otras especies de la familia, pero existen algunas diferencias importantes tales como la osificación tardía de los próoticos y la osificación premetamórfica de neopalatino, vómer, cuadrado-yugal, pterigoides y columela. El lento desarrollo ulterior de la osificación resulta en juveniles con cráneos extensamente cartilaginosos.

ABSTRACT. Characteristics of the cranial ossification in Phyllomedusa …