A rapid Agrobacferium fumefaciens-mediated transformation system for wheat was developed using freshly isolated immature embryos, precultured immature embryos, and embryogenic calli as explants. l h e explants were inoculated with a disarmed A. tumefaciens strain C58 (ABI) harboring the binary vector pMON18365 containing the p-glucuronidase gene with an intron, and a selectable marker, the neomycin phosphotransferase II gene. Various factors were found to influence the transfer-DNA delivery efficiency, such as explant tissue and surfactants present in the inoculation medium. The inoculated immature embryos or embryogenic calli were selected on G418-containing media. Transgenic plants were regenerated from all three types of explants. The total time required from inoculation to the establishment of plants i n soil was

Full-length cDNA clones corresponding to the transcripts of the two alpha-tubulin genes in Chlamydomonas reinhardi were isolated. DNA sequence analysis of the cDNA clones and cloned gene fragments showed that each gene contains 1,356 base pairs of coding sequence, predicting alpha-tubulin products of 451 amino acids. Of the 27 nucleotide differences between the two genes, only two result in predicted amino acid differences between the two gene products. In the more divergent alpha 2 gene, a leucine replaces an arginine at amino acid 308, and a valine replaces a glycine at amino acid 366. The results predicted that two alpha-tubulin proteins with different net charges are produced as primary gene products. The predicted amino acid sequences are 86 and 70% homologous with alpha-tubulins from rat brain and Schizosaccharomyces pombe, respectively. Each gene had two intervening sequences, located at identical positions. Portions of an intervening sequence highly conserved between the two beta-tubulin genes are also found in the second intervening sequence of each of the alpha genes. These results, together with our earlier report of the beta-tubulin sequences in C. reinhardi, present a picture of the total complement of genetic information for tubulin in this organism.

Education researchers have suggested that the academic challenges faced by many ethnic minority students are linked to perceived cultural discontinuity between students' home-and school-based experiences.However, there has been very little empirical inquiry into the existence and effects of cultural discontinuity for these students. The purpose of this article is to offer a definition and methodology to be used in the quantitative investigation of cultural discontinuity. A description of the cultural values and corresponding behaviors of African American, Asian American, Latino, and Native American students, along with those values and behaviors salient in most public schools, is offered. Next, a method for investigating cultural discontinuity is proposed. Finally, future research directions to further examine cultural discontinuity are offered.

Two genes from Arabidopsis thaliana related to the auxin-inducible Aux28 and Aux22 genes of soybean have been isolated. These genes belong to a small multi-gene family and are similar to the soybean Aux gene family in the sequence of the predicted proteins, intron/exon locations, and auxin-enhanced expression of their transcripts. Application of auxin to 8-day old Arabidopsis plants, 4-day old etiolated seedlings, and suspension culture cells all resulted in enhanced Aux transcript levels. Comparison of the promoter sequences from the soybean and Arabidopsis genes yielded no significant sequence conservation; however, three regions of near sequence identity are present between the two Arabidopsis Aux genes.

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Fruit ripening is a complex developmental process that involves specific changes in gene expression and cellular metabolism. In climateric fruits these events are coordinated by the gaseous hormone ethylene, which is synthesized autocatalytically in the early stages of ripening. Nonclimacteric fruits do not synthesize or respond to ethylene in this manner, yet undergo many of the same physiological and biochemical changes associated with the production of a ripe fruit. To gain insight into the molecular determinants associated with nonclimacteric fruit ripening, we examined mRNA populations in ripening strawberry fruit using polymerase chain reaction (PCR) differential display. Five mRNAs with ripening-enhanced expression were identified using this approach. Three of the mRNAs appear to be fruit-specific, with little or no expression detected in vegetative tissues. Sequence analysis of cDNA clones revealed positive identities for three of the five mRNAs based on homology to known proteins. These results indicate that the differential display technique can be a useful tool to study fruit ripening and other developmental processes in plants at the RNA level.

A full-length cDNA encoding a heat shock protein (hsp) belonging to the 83 to 90 kilodalton hsp family of Arabidopsis thaliana has been isolated and sequenced. Truncated cDNA clones were isolated by nucleic acid hybridization to a truncated soybean HSP83 cDNA probe and a fragment generated from a Drosophila HSP83 gene. A single strand DNA vector/primer based extension procedure was employed to obtain the full-length cDNA. The level of transcripts homologous to this cDNA (AtHS83) is low in 2-weekold Arabidopsis plants but is rapidly enhanced by elevated temperatures. DNA sequence comparison between this cDNA and hsp83-90 sequences from human, yeast and Drosophila reveal amino acid identities of 63 to 69%, typical identities for interspecies comparisons between hsp83 to 90 kilodalton proteins. Genomic DNA blot analysis performed with probes derived from AtHS83 indicate the presence of a HSP83 gene family estimated to be comprised of at least three genes. of regulation, controlling a variety of cellular functions (18). An additional function of hsp83-90 kD proteins during the heat shock response is postulated to be the modulation of eIF-2a phosphorylation and subsequent regulation of translation of cellular mRNAs (27).Genomic and cDNA clones of hsp83 to 90 sequences have been isolated and characterized from a number of species including human (13, 26), mouse (21), Drosophila (4), fungi (5, 9), trypanosomes (8), and maize and cabbage (personal communication cited in reference 24); a procaryotic counterpart, the E. coli htpG gene has also been identified and characterized (1). While the synthesis of hsp induced by elevated temperatures has been studied in a variety of plant species (23, 30), very little characterization of hsp83-90 genes and their transcripts has been reported. In this study, we report the complete sequence of a plant hsp83 cDNA isolated from Arabidopsis thaliana, and examine its expression in response to heat shock.The induction of the hsp3, a group of proteins synthesized in response to elevated temperatures, exists in almost every organism studied to date (28). The role of hsp has been under intense investigation; their role in thermotolerance or protection of cells from a variety of other stresses is the subject of recent reviews (15,18

A convenient cluster sample of 105 undergraduate students at a regional university in the midsouth completed a survey regarding their use of college textbooks, what strategies might increase the likelihood of their reading textbook assignments, and their preference for how class time was used.  Descriptive analysis wa sconducted on the results and chi-square was run on 25 selected comparisons,with a Bonferroni correction of the resulting alphas.  About half the students reported that they do read the assigned textbook readings. Freshmen were significantly more likely to report that outside reading should not be required of students prior to comingto class, and less likely to report having used or known about e-textbooks. Strategies reported to most likely prompt reading the textbook included in-class quizzes over text material, assigning graded study-guides to complete while reading; testing over material found in the textbook but not covered in class; and assigning shorter reading assignments. Preferences for use of class time varied by experience in college, but the majority of students preferred group discussion and application of material to real life rather than just lecture over the textbook content.