THE PRIMARY ROOT EPIDERMIS OF PANICUM VIRGATUM L. I. ONTOGENY AND FINE STRUCTURE OF THE EPIDERMAL CYTOPLASMIC INCLUSIONS

The ontogeny of large, globular, epidermal cytoplasmic inclusions (ECI) in P. virgatum roots was studied at the ultrastructural level. These ECI were seen to originate in meristematic cells as small electron translucent vesicles. Subsequently, the ECI, which appeared to be temporary storage sites, were seen to enlarge and increase in density by accumulating masses of a granular matrix as well as some small vesicular inclusions. In the zone of elongation, as the epidermal cells matured, the ECI within each cell gradually fused and the contents were lost. The pattern of the ontogeny of the ECI in the growing epidermal cells was consistent with the presence of cells of different physiologies in the zone of cell elongation of these roots.     

Transient state isoelectric focusing: effects of zone load and carrier ampholyte concentration on the kinetics of defocusing and refocusing in sucrose density gradients

The kinetics of focusing, defocusing, and refocusing of l-histidyl-l-tyrosine in a sucrose density gradient have been studied utilizing a special apparatus for repetitive scanning of the isoelectric focusing column, employing uv absorption optics and a digital data acquisition system. Starting from a uniform or triangular concentration profile, the band is “focused” and a nearly linear pH gradient is formed during initial focusing. The electrical field is then abolished and free diffusion occurs. The electrical field is then reapplied (“refocusing”) and the band is allowed to sharpen, presumably reapproaching a steady state. The band width was measured quantitatively as the second moment about the mean (square of the standard deviation, σ²). In theory, measurements of σ² versus time permit the estimation of the apparent diffusion coefficient (D) and the isoelectric focusing parameter (pE). If the electrical field strength E and the pH gradient, $\text{d(}\text{pH}\text{)}\text{dx}$, were also measured, then one could calculate the slope of the pH mobility curve of the protein $\text{dM}\text{d(}\text{pH}\text{)}$ evaluated at the isoelectric point. D can be measured during the defocusing stage, and $\text{pE,}\text{D}\text{pE}\text{,}\text{or}\text{D}$ can be measured during focusing or refocusing. Several limitations and difficulties in the verification of this theory have been encountered: First, the apparent diffusion coefficient depends on zone load in approximately a linear fashion. Accordingly, it is necessary to measure D at several zone loads, and then extrapolate to zero load by linear regression techniques. Second, the ampholyte concentration has a marked effect on both D and pE. Here we have no a priori reason to extrapolate to zero ampholyte concentration. Also, at present we have no satisfactory method for measurement of E. These preliminary studies should be helpful in indicating further directions for experimental refinement and for generalization of theory.     

Women of Principle: Female Networking in Contemporary Mormon Polygyny

Women of Principle: Female Networking in Contemporary Mormon Polygyny. Janet Bennion. New York: Oxford University Press. 1998. 178 pp.     

Why Doesn't the Creed Read "Always Be Critical"? An Examination of a Liberal Curriculum

Using ethnographic data collected in a second grade classroom over the course of a school year, this paper describes the ways in which one school's discourse of liberalism is deleteriously deployed. We view the school's discipline creed as emblematic of the school's liberal curriculum, and interrogate the effects on four African American boys in the classroom when the school enacts this creed. Despite the agency that these boys obviously had, they were unable to control the ways in which they were placed at a structural disadvantage and manipulated by a system far more powerful than they were. The results were that these four boys suffered. Not only did the intended liberal curriculum fail to be translated fully into the enacted curriculum, the liberal underpinnings of this curriculum precluded teachers and students from taking any critical stance.