How the tissues of a developing organism are reproducibly patterned has been a major question in biology. Under adequate conditions, a single fertilized cell can generate a full variety of mature cell types and organize them into a developed organism. In order to accomplish these complex tasks of self-organization, positional and temporal information must be provided to individual cells to ensure that the right developmental events occur at appropriate times. This is at least partially assisted by the specification of spatial and temporal axes formed and maintained during development. One way to define position and time within a developing organism is to form spatial or temporal gradients of signaling molecules, which patterns tissues in a concentration-dependent manner. A critical challenge of such gradient based patterning mechanisms is to maintain the desired gradient profiles of signaling molecules in a heterogeneous and fluctuating cellular environment. In this thesis, I describe how spatial and temporal gradients of signaling molecules can be refined and maintained during development of the model organism Caenorhabditis elegans. Using quantitative measurement techniques and analyses, I find that such tasks can be achieved by the balance between the activities of gradient forming signaling molecules and their antagonistic counterparts.

In 2016 Current Topics in Developmental Biology (CTDB) will celebrate its 50th or “golden anniversary. To commemorate the founding of CTDB by Aron Moscona (1921-2009) and Alberto Monroy (1913-1986) in 1966, a two-volume set of CTDB (volumes 116 and 117), entitled Essays on Development, will be published by Academic Press/Elsevier in early 2016. The volumes are edited by Paul M. Wassarman, series editor of CTDB, and include contributions from dozens of outstanding developmental biologists from around the world. Overall, the essays provide critical reviews and discussion of developmental processes for a variety of model organisms. Many essays relate the history of a particular area of research, others personal experiences in research, and some are quite philosophical. Essays on Development provides a window onto the rich landscape of contemporary research in developmental biology and should be useful to both students and investigators for years to come. Covers the area of developmental processes for a variety of model organisms International board of authors Part of two 50th Anniversary volumes proving a comprehensive set of reviews edited by Serial Editor Paul M. Wassarman

Comprehensive Overview of Advances in OlfactionThe common belief is that human smell perception is much reduced compared with other mammals, so that whatever abilities are uncovered and investigated in animal research would have little significance for humans. However, new evidence from a variety of sources indicates this traditional view is likely

Gradients and Tissue Patterning, Volume 137 in the Current Topics in Developmental Biology series, highlights new advances in the field, with this new volume presenting interesting chapters on a variety of timely topics. Each chapter is written by an international board of authors.

Development is behind what one looks like. It is directed by genes, the units of heredity, which are made up to deoxyribonucleic acid (DNA) in all animals (including man), plants, microorganisms and most of the viruses except in some viruses where ribonucleic acid (RNA) is the genetic material. Developmental Genetics integrates the two disciplines of development and genetics into one. Key Features: Each chapter begins with a brief introduction and historical background. The text explains both classical and recent material. Various phenomena of developmental genetics explained with examples of animals, plant, bacteria and viruses. Text explained with suitable examples, illustrations, tables and figures. List of references and review questions given at the end of each chapter Exhaustive glossary, author index and subject index given at the end of the book. This book is essential reading for postgraduate in developmental genetics, teachers teaching this subject and developmental biologists conducting research in this area. It is also suitable for candidates preparing for ARS/UGC NET examination.

International Review of Cell & Molecular Biology presents current advances and comprehensive reviews in cell biology—both plant and animal. Articles address structure and control of gene expression, nucleocytoplasmic interactions, control of cell development and differentiation, and cell transformation and growth. * Authored by some of the foremost scientists in the field * Provides up-to-date information and directions for future research * Valuable reference material for advanced undergraduates, graduate students and professional scientists

Scientific Frontiers in Developmental Toxicology and Risk Assessment reviews advances made during the last 10-15 years in fields such as developmental biology, molecular biology, and genetics. It describes a novel approach for how these advances might be used in combination with existing methodologies to further the understanding of mechanisms of developmental toxicity, to improve the assessment of chemicals for their ability to cause developmental toxicity, and to improve risk assessment for developmental defects. For example, based on the recent advances, even the smallest, simplest laboratory animals such as the fruit fly, roundworm, and zebrafish might be able to serve as developmental toxicological models for human biological systems. Use of such organisms might allow for rapid and inexpensive testing of large numbers of chemicals for their potential to cause developmental toxicity; presently, there are little or no developmental toxicity data available for the majority of natural and manufactured chemicals in use. This new approach to developmental toxicology and risk assessment will require simultaneous research on several fronts by experts from multiple scientific disciplines, including developmental toxicologists, developmental biologists, geneticists, epidemiologists, and biostatisticians.