Robert D. Smith

The Role of Metal Transport and Tolerance in Nickel Hyperaccumulation by Thlaspi goesingense Halacsy.

Metal hyperaccumulators are plants that are capable of extracting metals from the soil and accumulating them to extraordinary concentrations in aboveground tissues (greater than 0.1% dry biomass Ni or Co or greater than 1% dry biomass Zn or Mn). Approximately 400 hyperaccumulator species have been identified, according to the analysis of field-collected specimens. Metal hyperaccumulators are interesting model organisms to study for the development of a phytoremediation technology, the use of plants to remove pollutant metals from soils. However, little is known about the molecular, biochemical, and physiological processes that result in the hyperaccumulator phenotype. We investigated the role of Ni tolerance and transport in Ni hyperaccumulation by Thlaspi goesingense, using plant biomass production, evapotranspiration, and protoplast viability assays, and by following short- and long-term uptake of Ni into roots and shoots. As long as both species (T. goesingense and Thlaspi arvense) were unaffected by Ni toxicity, the rates of Ni translocation from roots to shoots were the same in both the hyper- and nonaccumulator species. Our data suggest that Ni tolerance is sufficient to explain the Ni hyperaccumulator phenotype observed in hydroponically cultured T. goesingense when compared with the Ni-sensitive nonhyperaccumulator T. arvense.

Thermal acclimation and whole-plant carbon balance in Zostera marina L. (eelgrass)

Thermal acclimation in eelgrass Zostera marina L. was investigated in laboratory experiments after growing plants at 10 and 20°C for 21 days under a 12:12 L:D regime. Metabolic rates showed significant shifts in short-term response to temperature in leaves and roots. Growth rates, tissue carbohydrate concentrations and metabolic rates measured at the two growth temperatures were statistically identical, indicating that thermal acclimation was essentially complete at these temperatures. When measured at pO2 values high enough to achieve capacity rates of respiration, thermal responses of respiration (Q10) were lower than previously reported while the thermal response of photosynthesis (measured at pO2 below air saturation) was similar to previous reports. Daily C budgets constructed from metabolic rate data indicated that Hsat periods required for photosynthesis to balance C demand can vary from 3 to > 12 h, depending on the ratios of net photosynthesis: respiration (Pnet: R) and shoot: root. Since Z. marina. shows evidence of thermal acclimation, seasonal changes in ambient temperature may not significantly affect Hsat requirements and whole-plant C balance. Rapid mortality at high temperatures during summer may result instead from thermal disruption of metabolism while internal C reserves may be important in meeting C demand during winter periods of low light availability, particularly among high-latitude populations.

University-level Computer-assisted Instruction at Stanford: 1975

This article provides an overview of current work on university-level computer-assisted instruction at Stanford University. Brief descriptions are given of the main areas of current interest. The main emphasis is on the courses now being used: Introduction to Logic, Axiomatic Set Theory, Old Church Slavonic, History of the Russian Literary Language, Introduction to Bulgarian, Introduction to BASIC, Introduction to LISP, and various courses in music.

Pro-Inflammatory Enzymes, Cyclooxygenase 1, Cyclooxygenase 2, and 5-Lipooxygenase, Inhibited by Stabilized Rice Bran Extracts

Rice bran, the outer bran and germ of the kernel and a by-product of rice milling, is rich in phytonutrients but has been underutilized because of lipid content instability. New methods for the processing of rice bran have yielded a stabilized form that is increasingly used in foods and dietary supplements. Recent studies have documented a role for stabilized rice bran (SRB) in treating diabetes and arthritis, although little is known of the bioactive compounds that impart these health benefits. Here we characterize the chemical composition of three extracts of SRB and identify the functional bioactives contributing to the inhibitory properties against three key pro-inflammatory enzymes (cyclooxygenase [COX] 1, COX2, and 5-lipoxygenase [5-LOX]) that control the inflammatory cascade involved in impaired joint health, pain, and arthritis. One extract (SRB-AI) demonstrated significant COX1 and COX2 inhibitory activities with 50% inhibitory concentration (IC(50)) values for COX1 and COX2 of 305 and 29 microg/mL, respectively, but no 5-LOX inhibition. The second extract (SRB-AII) inhibited COX1, COX2, and 5-LOX with IC(50) values of 310, 19, and 396 microg/mL, respectively. The third extract (SRB-AIII), a blend of SRB-AI and SRB-AIII, inhibited COX1, COX2, and 5-LOX with respective IC(50) values of 48, 11, and 197 microg/mL. Analysis of the extracts by direct analysis in real time time of flight-mass spectrometry revealed that SRB-AI, SRB-AII, and SRB-AIII contain over 620, 770, and 810 compounds, respectively. Of these, 17 were identified as key bioactives for COX and/or LOX inhibition. These SRB extracts have applications for functional foods and dietary supplements for control of inflammation and joint health.

Inhibition of fungal spore adhesion by zosteric Acid as the basis for a novel, nontoxic crop protection technology.

ABSTRACT To explore the potential for nontoxic crop protection technologies based on the inhibition of fungal spore adhesion, we have tested the effect of synthetic zosteric acid (p-(sulfo-oxy) cinnamic acid), a naturally occurring phenolic acid in eelgrass (Zostera marina L.) plants, on spore adhesion and infection in two pathosystems: rice blast caused by Magnaporthe grisea and bean anthracnose caused by Colletotrichum lindemuthianum. We have shown that zosteric acid inhibits spore adhesion to model and host leaf surfaces and that any attached spores fail to develop appressoria, and consequently do not infect leaf cells. Low concentrations of zosteric acid that are effective in inhibiting adhesion are not toxic to either fungus or to the host. The inhibition of spore adhesion in the rice blast pathogen is fully reversible. On plants, zosteric acid reduced (rice) or delayed (bean) lesion development. These results suggest that there is potential for novel and environmentally benign crop protection technologies based on manipulating adhesion.

Molecular cloning and chromosomal mapping of type one serine/threonine protein phosphatases in Arabidopsis thaliana

Type one serine/threonine protein phosphatases (PP1s) have been implicated in various processes of plant growth and development. In all plant species studied, PP1s are encoded by multigene families. Previous studies in our laboratory identified five Arabidopsis thaliana PP1 genes (TOPP1, TOPP2, TOPP3, TOPP4 and TOPP5). In the present study, we report the isolation of three additional PP1 genes (TOPP6, TOPP7 and TOPP8). Southern blot analyses indicate that these three newly isolated genes are single-copy genes in A. thaliana genome. All the three genes are expressed in roots, rosettes and flowers, although their expression levels appear to be lower than those of the five previously identified TOPP genes. Six of the eight TOPP genes were mapped to different positions on four of five A. thaliana chromosomes. Sequence comparison revealed that TOPP genes belong to different subgroups of plant PP1 genes, suggesting that they may encode proteins with distinct functions.

BITS based imaging process

Many universities use Symantec Ghost to image PCs in their campus computer labs. However, issues related to network traffic, multicasting, and file size create numerous difficulties when transferring image files.Tim Leamy at University of California, Davis (UC Davis) created a system using Microsofts Background Intelligent Transfer Service (BITS) to transfer Ghost images to PC. Allan Chen and Rob Smith have adapted the system to work at Stanford.The system uses BITS to transfer Symantec Ghost .gho and .ghs files to a FreeDOS partition on the client PC. The machine then rebuilds itself at the next reboot locally, making for extremely fast imaging times.BITS, which utilizes standard HTTP protocols, runs in the background using available network bandwidth. This leaves the workstation available for use by students. Because the file transfer is via HTTP, it works over all types of networking and is very robust. The image files themselves are stored on a standard web server. Actual downtime of the client is generally less than 10 minutes.Stanford University has adapted the UC Davis solution in a number of ways. The majority of the work has been in dealing with larger (14GB) image sizes and integrating the scripts and utilities into the Stanford environment. Scripting functionality has remained the same, though many of the actual scripts have been modified.This presentation will examine the original impetus and implementation at UC Davis, and Stanfords experiences in modifying that process to fit our needs.