Life Sciences Commons^™

Cloning And Conservation Of Biological Diversity: Paradox, Panacea, Or Pandora's Box?, Shaily Menon, Kamaljit Bawa, Leah Gorman

Shaily Menon

The success of a Scottish team in cloning a mammal from an adult tissue cell has generated considerable speculation in the popular press about potential applications to conservation biology. Possibilities that have been mentioned include cloning endangered species and creating gene banks for the germplasm of rare species. Sensational or inaccurate reports might encourage the mistaken notion that cloning technology is more advanced or reliable than it actually is. More important, such reports might foster the myth that there is no longer an urgency to conserve endangered species or their habitats as long as we have frozen germplasm and cloning …

Wounding-Induced Cell Wall Ph Shifts In Coleoptile Segments Of Various Poaceae, Winfried Peters

Winfried S. Peters

Genes That Guide Growth Cones Along The C. Elegans Ventral Nerve Cord, Bruce Wightman, Renee Baran, Gian Garriga

Renee Baran

During nervous system development, growth cone pioneering and fasciculation contribute to nerve bundle structure. Pioneer growth cones initially navigate along neuroglia to establish an axon scaffold that guides later extending growth cones. In C. elegans, the growth cone of the PVPR neuron pioneers the left ventral nerve cord bundle, providing a path for the embryonic extensions of the PVQL and AVKR growth cones. Later during larval development, the HSNL growth cone follows cues in the left ventral nerve cord bundle provided by the PVPR and PVQL axons. Here we show that mutations in the genes enu-1, fax-1, unc-3, unc-30, unc-42 …

Iaa Breakdown And Its Effect On Auxin-Induced Cell Wall Acidification In Maize Coleoptile Segments, Winfried Peters, Christa Lommel, Hubert Felle

Winfried S. Peters

Thermodynamics Of Oligoarginines Binding To Rna And Dna., David Mascotti, Timothy Lohman

David P. Mascotti

These results suggest that hydrogen bonding of arginine to the phosphate backbone of the nucleic acids contributes to the increased stability of these complexes.

The Determination Of Relative Elemental Growth Rate Profiles From Segmental Growth Rates (A Methodological Evaluation), Winfried Peters, Nirit Bernstein

Winfried S. Peters

The Cold Shock Domain Protein Lin-28 Controls Developmental Timing In C. Elegans And Is Regulated By The Lin-4 Rna, Eric Moss, Rosalind Lee, Victor Ambros

Victor R. Ambros

Mutations in the heterochronic gene lin-28 of C. elegans cause precocious development where diverse events specific to the second larval stage are skipped. lin-28 encodes a cytoplasmic protein with a cold shock domain and retroviral-type (CCHC) zinc finger motifs, consistent with a role for LIN-28 in posttranscriptional regulation. The 3'UTR of lin-28 contains a conserved element that is complementary to the 22 nt regulatory RNA product of lin-4 and that resembles seven such elements in the 3'UTR of the heterochronic gene lin-14. Both lin-4 activity and the lin-4-complementary element (LCE) are necessary for stage-specific regulation of lin-28. Deleting the LCE …

The Role Of Molecular Recognition In Activation And Regulation In The Growth Hormone-Prolactin Family Of Hormones And Receptors, Anthony Kossiakoff, Celia Schiffer, Abraham De Vos

Celia A. Schiffer

In: Rick L. Ornstein, Biomacromolecules--from 3-D to applications: Thirty-fourth Hanford Symposium on Health and the Environment, October 23-26, 1995, Pasco, Washington, U.S.A. Battelle Press, 1997, p. 123-131. ISBN 1574770195, 9781574770193.

Population Thinking And Tree Thinking In Systematics, Robert O’Hara

Robert J. O’Hara

Two new modes of thinking have spread through systematics in the twentieth century. Both have deep historical roots, but they have been widely accepted only during this century. Population thinking overtook the field in the early part of the century, culminating in the full development of population systematics in the 1930s and 1940s, and the subsequent growth of the entire field of population biology. Population thinking rejects the idea that each species has a natural type (as the earlier essentialist view had assumed), and instead sees every species as a varying population of interbreeding individuals. Tree thinking has spread through …

Effectiveness Of The Protected Area Network In Biodiversity Conservation: A Case-Study Of Meghalaya State, M. Latif Khan, Shaily Menon, Kamaljit Bawa

Shaily Menon

The North-Eastern region of India is significant for biodiversity conservation because of its floristic richness and high levels of endemism. Deforestation levels are high in the region due to anthropogenic pressures. We accessed various literature sources to create a database for Meghalaya state containing information on plant species, habit, altitudinal distribution, endemism, and endangered status. Information on the existing protected area network (type, extent, and altitudinal representation) was added to the database. The database was used to assess the effectiveness of the existing protected area network in conserving the floristic biodiversity of the state. Of a total of 3331 plant …

Time-Averaging Crystallographic Refinement, Celia Schiffer

Celia A. Schiffer

In: Wilfred F. van Gunsteren and Paul K. Weiner, Computer Simulation of Biomolecular Systems: Theoretical and Experimental Applications (Volume 3 of Computer Simulation of Biomolecular Systems), Springer, 1997, p. 265-269. ISBN 9072199251, 9789072199256.

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Heterochronic Genes, Victor Ambros

Victor R. Ambros

This chapter focuses on our current understanding of the C. elegans heterochronic gene pathway as determined by genetic characterization of the regulatory interactions among the genes (Ambros and Horvitz 1987; Ambros 1989; Liu and Ambros 1989) and recent progress on the cloning, sequencing, and molecular analysis of genes involved in this pathway (Ruvkun et al. 1989; Arasu et al. 1991; Papp et al. 1991; Wightman et al. 1991; Lee et al. 1993; Rougvie and Ambros 1995; E. Moss et al., in prep). Primary emphasis is placed on the developmental decisions controlled by the heterochronic genes, the regulatory interactions among genes …

Root-Soil Contact For The Desert Succulent Agave Deserti Engelm. In Wet And Drying Soil, Gretchen North, P. Nobel

Gretchen North

To investigate the extent and size of root-soil air gaps that develop during soil drying, resin casts of roots of the desert succulent Agave deserti Engelm. were made in situ for container-grown plants and in the field. Plants that were droughted in containers for 7 and 14 d had 24 and 34% root shrinkage, respectively, leading to root-soil air gaps that would reduce the hydraulic conductivity at the root-soil interface by a factor of about 5. When containers were vibrated during drought, root-soil air gaps were greatly diminished, and the predicted conductivity at the interface was similar to that of …

Biodiversity Monitoring: The Missing Ingredient, Kamaljit Bawa, Shaily Menon

Shaily Menon

With mounting losses in biological diversity, inventorying and monitoring of biodiversity to assess the magnitude and rate of losses are emerging as dominant themes in conservation biology. Inventorying has been defined as the surveying, sorting, cataloging, quantifying and mapping of entities ranging from genes to landscapes1 and monitoring has been defined as the surveillance of the compliance with or deviation from a predetermined standard2. Renner and Ricklefs3 argued that rushed inventories will compromise scientific rigor and have little influence on decision making. More recently, Stork et al.4 argued that losses in biological diversity are so severe that inventorying and monitoring …

The Pax-5 Gene Is Alternatively Spliced During B-Cell Development, Patty Zwollo, Hector Arrieta, Kaleo Ede, Karen Molinder, Stephen Desiderio, Roberta Pollock

Roberta Pollock

The transcription factor Pax-5 is expressed during the early stages of B-cell differentiation and influences the expression of several B-cell-specific genes. In addition to the existing isoform (Pax-5, which we have named Pax-5a), we have isolated three new isoforms, Pax-5b, Pax-5d, and Pax-5e, from murine spleen and B-lymphoid cell lines using library screenings and polymerase chain reaction amplification. Isoforms Pax-5b and Pax-5e have spliced out their second exon, resulting in proteins with only a partial DNA-binding domain. Isoforms Pax-5d and Pax-5e have deleted the 3′-region, which encodes the transactivating domain, and replaced it with a novel sequence. The existence of …

Genetic Analysis Of Chlorophyll Biosynthesis, David W. Bollivar, Jon Y. Suzuki, Carl E. Bauer

David Bollivar

During this decade, there have been major advancements in the understanding of genetic loci involved in synthesis of the family of Mg-tetrapyrroles known as chlorophylls and bacteriochlorophylls. Molecular genetic analysis of Mg-tetrapyrrole biosynthesis was initiated by the performance of detailed sequence and mutational analysis of the photosynthesis gene cluster from Rhodobacter capsulatus. These studies provided the first detailed understanding of genes involved in bacteriochlorophyll a biosynthesis. In the short time since these studies were initiated, most of the chlorophyll biosynthesis genes have been identified by virtue of their ability to complement bacteriochlorophyll a biosynthesis mutants as well as by sequence …