Pollen transmits the male genetic material in sexual reproduction of all higher plants. This same pollen is also well suited as a research tool for studying many patterns of plant and animal metabolism. In addition, an increased knowledge of pollen may help plant breeders accelerate efforts to improve the world's food and fiber supply. This volume focuses upon pollen biology and chemistry; it attempts to inte grate these facts with management practices involved in pollen applications. People have long been involved with pollen. Pollen applications are recorded in the rites of ancient civilizations (see Frontispiece). From the earliest times many benefits have been attributed to the inclusion of pollen in man's diet; also, since the mid-19th century air-borne pollen has been recognized as detrimental to many people's health. Disciplines concerned with man's cultural history and the earth's changing ecology find pollen a particularly useful and accessible tool. Identifiable parts of pollen have survived over 100 million years. But most books dealing with pollen are generally concerned with the identification of the plant source, an aspect of the science of palynology; other books emphasize the natural vectors transmit ting pollen, the pollination mechanisms. Very few works include the biochem istry or biology of pollen. Yet extensive studies by physicians, as well as plant breeders and apiculturists, have contributed a sizeable body of research relating to pollen.
Cellular division is crucial to proper development and homeostasis in all multicellular organisms, and therefore must be tightly regulated at multiple steps, and by multiple factors capable of integrating mitogenic signals. The majority of human cancers bypass these checkpoints, unavoidably resulting in hyper-proliferation and death. The `decision' to divide is largely controlled by gate-keeper to the G1/S phase transition, retinoblastoma/pRb. The diversity of human cancers to which retinoblastoma is genetically or functionally inactivated speaks to its wide importance in cell cycle regulation. pRb was originally characterized as a transcriptional repressor, acting through the E2F family of transcription factors to regulate the transcription of genes essential to progression through S phase. A quarter century on, retinoblastoma has been found to interact with hundreds of proteins, implicating pRb in diverse aspects of development, the maintenance of chromatin structure, and genome stability. In order to gain insight into the non-cell cycle roles of lin-35 /Rb in C. elegans development, we performed multiple genome-wide RNAi screens for suppressors of lin-35 synthetic phenotypes. Upon completion of these screens, and subsequent biochemical assays, we have clarified new roles for LIN-35/pRb in nutrient utilization, pharyngeal development, and the maintenance of somatic cell fates. The overlapping nature of these screens allowed us to identify a new class of genes specifically antagonistic to LIN-35/pRb in diverse developmental contexts. Based on this work, we hypothesize that several of the antagonistic MPLS genes represent possible cancer therapeutic targets, if inactivated in a tissue-specific manner. We also describe redundant roles for LIN-35/pRb and essential gene PHA-1 in the development of the C. elegans foregut. Our analysis of a pharyngeal regulatory complex SUP-35/SUP-36/SUP-37 and its upstream regulators has served to partially unraveled the network of genes essential to foregut development. Furthermore, expression analysis, yeast two-hybrid screening, and a genome-wide RNAi screen have placed all three SUPs together, acting at the same temporal and spatial stage to antagonize pharynx development. Taken together, my work has clarified novel roles for lin-35/Rb in nutrient utilization and foregut development in C. elegans , as well as contributed to a growing understanding of retinoblastoma as a crucial factor in the maintenance of somatic cell fates. Furthermore, this work contributes to a shift taking place in the understanding of pRb's role in transcriptional regulation, from a direct repressor of individual gene transcription, to a global regulator of chromatin structure.
The House of Commons volumes, part of the History of Parliament series, are a major academic project describing the House's members, constituencies and activities covering the period 1386-1832. Consists of biographies of every person who sat as a member of the House during the period concerned; descriptions of each election during the period in each constituency; and an introductory survey, pulling together and analysing the information given in the biographies and constituency histories.
Thank you for visiting our website. Would you like to provide feedback on how we could improve your experience?
This site does not use any third party cookies with one exception — it uses cookies from Google to deliver its services and to analyze traffic.Learn More.