Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

1993

External Link

Articles 1 - 6 of 6

Full-Text Articles in Life Sciences

The C. Elegans Heterochronic Gene Lin-4 Encodes Small Rnas With Antisense Complementarity To Lin-14, Rosalind Lee, Rhonda Feinbaum, Victor Ambros Dec 1993

The C. Elegans Heterochronic Gene Lin-4 Encodes Small Rnas With Antisense Complementarity To Lin-14, Rosalind Lee, Rhonda Feinbaum, Victor Ambros

Victor R. Ambros

lin-4 is essential for the normal temporal control of diverse postembryonic developmental events in C. elegans. lin-4 acts by negatively regulating the level of LIN-14 protein, creating a temporal decrease in LIN-14 protein starting in the first larval stage (L1). We have cloned the C. elegans lin-4 locus by chromosomal walking and transformation rescue. We used the C. elegans clone to isolate the gene from three other Caenorhabditis species; all four Caenorhabditis clones functionally rescue the lin-4 null allele of C. elegans. Comparison of the lin-4 genomic sequence from these four species and site-directed mutagenesis of potential open reading frames …

Go to article

Thermodynamics Of Single-Stranded Rna And Dna Interactions With Oligolysines Containing Tryptophan. Effects Of Base Composition., David Mascotti, Timothy Lohman Oct 1993

Thermodynamics Of Single-Stranded Rna And Dna Interactions With Oligolysines Containing Tryptophan. Effects Of Base Composition., David Mascotti, Timothy Lohman

David P. Mascotti

No abstract provided.

Go to article

Genetic Analyses Of Photopigment Biosynthesis In Eubacteria: A Guiding Light For Algae And Plants, David Bollivar, Carl E. Bauer, Jon Y. Suzuki Jun 1993

Genetic Analyses Of Photopigment Biosynthesis In Eubacteria: A Guiding Light For Algae And Plants, David Bollivar, Carl E. Bauer, Jon Y. Suzuki

David Bollivar

A wide variety of macrocyclic tetrapyrrole compounds are synthesized by cells for use in diverse cellular processes. As shown in Fig. 1, this pathway includes the synthesis of closed tetrapyrrole compounds that contain metals, such as cobalt-containing cobalamin (vitamin B12), nickel-containing methanogenesis coenzyme F430, copper-containing pigment turacin, iron-containing heme and siroheme, and magnesium-containing chlorophylls and bacteriochlorophylls. Also synthesized by this pathway are a variety of open macrocyclic compounds such as the family of bilins that are used as a source of light-harvesting pigments in cyanobacteria, red algae, and cryptophytes as well as the chromophore that is covalently attached to phytochrome …

Go to article

A Bacterial Protease Perturbs The Paracellular Barrier Function Of Transporting Epithelial Monolayers In Culture, Ali Azghani May 1993

A Bacterial Protease Perturbs The Paracellular Barrier Function Of Transporting Epithelial Monolayers In Culture, Ali Azghani

Ali Azghani

Tight junctions between cells and adhesion to the substratum maintain the barrier function of epithelia throughout the body. Damage to the epithelial barrier by microbial products allows penetration of bacteria and promotion of infection. We studied the effects of Pseudomonas elastase (PE) on the barrier function of epithelia by using Madin-Darby canine kidney (MDCK) epithelial cells; these cells form tight junctions (zonula occludens [ZO]) in vitro. PE decreased electrical resistance across the monolayers in a concentration- and time-dependent manner. Immunostaining of selected proteins of the ZO and zonula adherens was used to explore the effects of PE on junctional proteins. …

Go to article

Avian Hatching Asynchrony: Brood Classification Based On Discriminant Function Analysis Of Nestling Masses, Given Harper, Steven A. Juliano, Charles F. Thompson May 1993

Avian Hatching Asynchrony: Brood Classification Based On Discriminant Function Analysis Of Nestling Masses, Given Harper, Steven A. Juliano, Charles F. Thompson

Given Harper

Studies of hatching asynchrony in altricial birds have used several methods to determine if a brood hatches synchronously or asynchronously. The most commonly used methods include making frequent nest visits during the time of hatching and using nestling mass or other measures of size on a given day to estimate nestling age or to describe the extent of the size hierarchy within broods. We made daily nest visits to determine if House Wren (Troglodytes aedon) broods hatched synchronously or asynchronously, and then compared classification of these broods based on discriminant function analysis with that based on mass differences of nestlings. …

Go to article

Effects Of Predator Size And Female Receptivity On Courtship Behavior Of Captive-Bred Male Guppies, Given Harper, Kristin Braun Dec 1992

Effects Of Predator Size And Female Receptivity On Courtship Behavior Of Captive-Bred Male Guppies, Given Harper, Kristin Braun

Given Harper

The effects of predator size and female receptivity on the courtship behavior of captivebred male guppies (Poecilia reticulata) were investigated. Male guppies exhibited riskreckless courtship behavior in that they did not decrease the amount of time spent performing visually conspicuous sigmoid displays and increase the frequency of attempted forced copulations when large predatory fish were present. Female receptivity (i.e., virgin or non-virgin females) also had no effect on male courtship behavior.

Go to article