Growth and Sink to Source Transition in Developing Leaves of Sugarbeet

The growth and sink to source transition (cessation of assimilateimport) in light-grown leaves were compared to those of dark-grownleaves. Darkening chambers were placed over sugarbeet (Betavulgaris L.) plants so that new leaves emerged and grew in thedark. New leaves emerged at 1.8 day intervals, regardless ofthe light conditions. The dark-grown leaves were reversiblyretarded in overall growth; they were unable to photosynthesize,but attained photosyn-thetic, vein loading and export capacityafter exposure to sufficient amount and duration of light. Despitethe inability to fix carbon, dark-grown leaves showed dry weightgain. The increase in the dry weight, however, was localizedin the petiole and major veins and not in the laminar tissue.Despite metabolic differences in the two leaf types, sink tosource transition occurred in about a week in both light- anddark-grown leaves; and assimilate importing stopped at about8 days after emergence. While sink to source transition (asdetermined by assimilate import) per se did not appear to belight-regulated, the ability to accumulate sucrose in the veinsfor export out.of leaves was light dependent. This was basedon the observation that post-transitional dark-grown leaveswhich had ceased importing could not export exogenously appliedsucrose unless they were exposed to light for several days.The data indicated that transition is developmentally regulatedand not coupled to photosynthetic capacity. ¹Contribution No. D-15192-1-89 from the New Jersey AgriculturalExperiment Station. This work was funded in part by the BeetSugar Development Foundation and Rutgers Universi ty ResearchCouncil and was submitted as partial fulfillment for M.S. degreeby Lynne H. Pitcher. (Received August 22, 1990; Accepted January 9, 1991)     

Differential Expression of Immune Response Genes in Steller Sea Lions (Eumetopias jubatus): An Indicator of Ecosystem Health?

Characterization of the polygenic and polymorphic features of the Steller sea lion major histocompatibility complex (MHC) provides an ideal window for evaluating immunologic vigor of the population and identifying emergence of new genotypes that reflect ecosystem pressures. MHC genotyping can be used to measure the potential immunologic vigor of a population. However, since ecosystem-induced changes to MHC genotype can be slow to emerge, measurement of differential expression of these genes can potentially provide real-time evidence of immunologic perturbations. MHC DRB genes were cloned and sequenced using peripheral blood mononuclear leukocytes derived from 10 Steller sea lions from Southeast Alaska, Prince William Sound, and the Aleutian Islands. Nine unique DRB gene sequences were represented in each of 10 animals. MHC DRB gene expression was measured in a subset of six sea lions. Although DRB in genomic DNA was identical in all individuals, relative levels of expressed DRB mRNA was highly variable. Selective suppression of MHC DRB genes could be indicative of geographically disparate environmental pressures, thereby serving as an immediate and sensitive indicator of population and ecosystem health.     

"The Divine Impatience": Ritual, Narrative, and Symbolization in the Practice of Martyrdom in Palestine

Violence is obscured by habits of thought, which predispose us to reject that which falls outside of our notion of "normal' human behavior. By dismissing as incomprehensible, or "pathologic" embodied practices that do not correspond to a "rationally ordered' everyday life, some anthropologists concerned with issues of violence forsake a fundamental responsibility to foster an understanding of phenomena that affronts, offends, or questions our own cultural norms and assumptions. Situations of violence, whether due to contextual or individual instability, by definition defy pregiven notions of "rationality" and "normal behavior." This article is about Palestinian martyrs, youths killed in confrontations with the Israeli military. It seeks to identify the cultural and psychological processes that make Palestinian martyrdom possible within the specific context of Israeli military occupation. It elaborates the ritual, narrative, and symbolic dimensions of a practice that exists within a Palestinian discourse of sacrifice and of national liberation. [Palestinian, martyrdom, embodiment, psychoanalysis, violence]