Texas A&M University

About: Texas A&M University is a education organization based out in College Station, Texas, United States. It is known for research contribution in the topics: Population & Finite element method. The organization has 72169 authors who have published 164372 publications receiving 5764236 citations.

Asexual Sporulation in Aspergillus nidulans

Abstract: The formation of mitotically derived spores, called conidia, is a common reproductive mode in filamentous fungi, particularly among the large fungal class Ascomycetes. Asexual sporulation strategies are nearly as varied as fungal species; however, the formation of conidiophores, specialized multicellular reproductive structures, by the filamentous fungus Aspergillus nidulans has emerged as the leading model for understanding the mechanisms that control fungal sporulation. Initiation of A. nidulans conidipohore formation can occur either as a programmed event in the life cycle in response to intrinsic signals or to environmental stresses such as nutrient deprivation. In either case, a development-specific set of transcription factors is activated and these control the expression of each other as well as genes required for conidiophore morphogenesis. Recent progress has identified many of the earliest-acting genes needed for initiating conidiophore development and shown that there are at least two antagonistic signaling pathways that control this process. One pathway is modulated by a heterotrimeric G protein that when activated stimulates growth and represses both asexual and sexual sporulation as well as production of the toxic secondary metabolite, sterigmatocystin. The second pathway apparently requires an extracellular signal to induce sporulation-specific events and to direct the inactivation of the first pathway, removing developmental repression. A working model is presented in which the regulatory interactions between these two pathways during the fungal life cycle determine whether cells grow or develop.

Designing sorghum as a dedicated bioenergy feedstock

Abstract: The increasing cost of energy and finite oil and gas reserves has created a need to develop alternative fuels from renewable sources Currently, the development of a renewable transportation fuel is ethanol based Ethanol production is now sugar/starch based, but use of these carbohydrates is limited; they are also required as a food and feed source The need to generate a large and sustainable supply of biomass to make biofuels generation from lignocellulose profitable will require the development of crops grown specifically for bioenergy production There will be several different species used as dedicated bioenergy crops, and for several reasons; it is expected that sorghum (Sorghum bicolor L Moench) will be one of these species Sorghum is a highly productive, drought-tolerant species with a history of improvement and production of lignocellulose, sugar and starch Given this history and the existing genetic improvement infrastructure available for the species, it is logical to expect that sorghum hybrids for dedicated bioenergy production can be developed in the near-term future and will be grown and used for bioenergy production © 2007 Society of Chemical Industry and John Wiley & Sons, Ltd

The Dynamics of Political Control of the Bureaucracy.

Abstract: A new paradigm of political-bureaucratic relations emerged through the 1980s holding that U.S. democratic institutions continuously shape nonelective public bureaucracies. Several empirical studies support the paradigm with evidence suggestive of political manipulation but none reveals the scope or specific mechanisms of political control. We explore the dynamics of political control of the bureaucracy explicitly to determine the scope and mechanisms. We examine output time series from seven different public bureaucracies for responsiveness to political tools applied in the late Carter and early Reagan administrations. We find responsiveness in all seven cases. The evidence also shows that political appointments—a shared power of the president and Congress—is the most important instrument of political control; changing budgets, legislation, congressional signals, and administrative reorganizations are less important. These findings confirm intuitive assertions by institutional scholars and suggest a method of “policy monitoring” that could enhance future democratic control of the bureaucracy.