A long-term study of knowledge, risk, and ethics for students enrolled in an introductory biotechnology course.

Since 1989, an undergraduate course addressing issues concerning biotechnology in agriculture has been taught annually. To determine the extent to which students were engaged in classroom instruction and assimilated knowledge from the course, students were asked to complete an "Attitudes About Biotechnology" questionnaire. Students were queried about their knowledge of biotechnology, perceptions of risks associated with biotechnology, and ethics and attitudes toward the use of biotechnology in agriculture. Responses to the survey questions were evaluated both pre-and postcourse. Data were collected from 13 classes over a 10-yr period. Inspection of the precourse grade point average and the course grades for these students revealed no trends up or down over the period of this study. Similarly, inspection of the data revealed no effect from problem-based learning, student-facilitated group work, or technology on student attainment of knowledge, perception of risk, or ethical views. For each of the five knowledge questions, the average score increased as a result of taking the course. On two of the knowledge questions, the average score increase for females from pre- to postcourse was greater than for males. Based on our measurements using the postcourse questionnaire, the correlation between perceived and actual knowledge was not significantly different from zero. In two of the four risk questions, there was no change in average score as a result of the course; however, student perception of risk associated with genetic engineering of plants increased. Although average scores for student perception of risk due to the perceived impact of genetically engineered products on people or the environment decreased from pre- to postcourse assessment, the average score was higher (P < 0.01) for females than for males. Males were more accepting of genetic manipulation of cells in a laboratory than were females both pre- and postcourse. Although student knowledge of biotechnology was increased and the perceived risk due to biotechnology was altered, there was no evidence that students altered their ethical position on biotechnology as a result of this course.

Acquired thermotolerance and expression of the HSP100/ClpB genes of lima bean.

Acquired thermotolerance (AT) is the ability of cells to survive a normally lethal temperature treatment as a consequence of pretreatment at an elevated but sublethal temperature. In yeast and cyanobacteria, the expression of the HSP100/ClpB protein is required for the AT response. To determine whether the HSP100/ClpB protein is associated with this response in lima bean (Phaseolus lunatus), we have cloned an HSP100/ClpB homolog and assessed expression of the two gene copies under heat stress conditions, which induce AT. Transcription of the cytoplasmically localized HSP100/ClpB protein genes is stringently controlled by heat stress in both of the laboratory and field heat stress conditions. From a heat-induced cDNA library, we identified a clone of a putative chloroplast-targeted (cp) HSP100/ClpB protein gene sequence. The cp HSP100/ClpB protein genes are constitutively expressed, but transcript levels increase post-heat stress in laboratory heat stress experiments. In field conditions the genes for the cp HSP100/ClpB are constitutively expressed. Although we were unable to correlate differences in the timing of AT response with the expression or genetic structure of the HSP100/ClpB genes in heat-tolerant or -sensitive varieties of lima bean, we clearly demonstrate the association of expression of HSP100/ClpB proteins with heat response in this species.

Occurrence and Partial Characterization of a New Mechanically Transmissible Virus in Mashua from the Ecuadorian Highlands.

Mashua (Tropaeolum tuberosum) is a tuber crop indigenous to the Andean highlands and of economic value to its native people as a food and medicinal crop. Field plants often exhibit symptoms typical of virus infection, including interveinal chlorosis, leaf cupping, distortion, and stunting. Using an herbaceous host range, at least 1 mechanically transmissible virus was detected in each of 10 accessions. All virus isolates tested reacted to potyvirus group antiserum in indirect enzyme-linked immunosorbent assays (ELISA). Results of monoclonal antibody testing using antigen coated plate (ACP) ELISA, where virions are disrupted to expose cryptotopes, indicated that isolate Tt 4 has epitopes in common with maize dwarf mosaic potyvirus A (MDMV-A). Polyclonal antiserum produced to purified preparations of the Tt 4 isolate reacted in indirect ELISA to Tt 4, the common strain of potato potyvirus Y (PVY-C), less strongly to tobacco etch potyvirus (TEV) and potato potyvirus A (PVA), but not to 11 other potyviruses, including MDMV-A. Conversely, the Tt 4 isolate reacted strongly in indirect ELISA to antisera to bean common mosaic potyvirus (BCMV) and watermelon mosaic potyvirus 2 (WMV-2), but not antisera to 12 other potyviruses. Our data suggest that isolate Tt 4 is a distinct potyvirus closely related to and sharing external epitopes with PVY-C, TEV, PVA, WMV-2, and BCMV, and buried epitopes with MDMV-A. The virus has been tentatively named Tropaeolum mosaic potyvirus (TropMV). A survey of T. tuberosum in Ecuador revealed that TropMV was widespread, being detected by ACP-ELISA in 34 of 46 accessions at the National Institute for Agricultural Research's Santa Catalina Research Station, Quito, and all eight production fields surveyed.

Identification of Embryoid-Abundant Genes That Are Temporally Expressed during Pollen Embryogenesis in Wheat Anther Cultures.

Uninucleate microspores in anther cultures of bread wheat (Triticum aestivum cv Pavon) are capable of producing haploid pollen embryoids and plants. To gain an understanding of this alternate pathway of pollen development, we constructed a cDNA library to young pollen embryoids, isolated embryoid-specific genes, and analyzed their expression patterns during morphogenesis. Two embryoid-abundant clones, pEMB4 and 94, were expressed very early during culture, suggesting that these genes are associated with development and are not simply expressed as a consequence of differentiation. The accumulation patterns of five cloned mRNAs may indicate the activation of specific genes associated with the major morphological and physiological activities connected with the differentiation of embryoids in vitro. These results suggest that embryoid-abundant gene expression is causally related to this pathway because gene expression is spatially and temporally specific and is not observed when microspores are cultured under noninductive conditions.

Measurement of endogenous ABA levels in chilled somatic embryos of carrot by immunoassay.

Somatic embryos of carrot, Daucus carota L. 'Royal Chantenay', were chilled at 4°C for the last 3 days of development in order to harden torpedo stage embryos to increase embryo survival during desiccation. ABA levels in chilled and non-chilled embryos were measured using a polyclonal radioimmunoassay and a monoclonal enzyme-linked immunosorbent assay (ELISA). The monoclonal ELISA is the preferred technique due to superior sensitivity and specificity. ABA levels, measured by either technique, were similar in chilled and non-chilled embryos. The relative water content was lower in chilled embryos than in non-chilled embryos and chilling altered protein secretion of one cell line.