Free energy analysis on the coding region of the individual genes of Saccharomyces cerevisiae.

Two methods, power spectrum density analysis (PSD) and synchronization signal approximation, were investigated to determine if underlying periodic, free energy signals could be detected for the individual genes in this paper. These signals could be revealed assuming Watson-Crick type hybridization between the eight, 3'-terminal nucleotides of the 18S rRNA and pre- and mature-mRNA sequences in Saccharomyces cerevisiae in a manner similar to that used to analyze coding region sequences in prokaryotic genes. Using PSD, a periodic signal could only be detected in 35 of 106 genes tested; using the synchronization signal approximation, 91 of 106 genes showed linearly increasing magnitude and phase, characteristics consistent with the presence of an underlying periodic signal with an assumed frequency of one-third. The majority of introns did not show magnitude and phase behavior consistent with an underlying non-periodic signal. The periodicity property for the free energy on the protein-coding regions can contribute to finding the approximate boundaries of the exons (protein coding regions) and the introns, which provides a foundation for future studies in identifying the exact positions of the splice sites, especially for the higher eukaryotic genes.

Early-flowering Scots pines through tissue culture for accelerating tree breeding.

Scots pine plantlets were produced via tissue culture using cotyledons excised from germinated embryos as explants. The optimum tissue culture conditions were: 1/2GDbasal medium gelled with agar-Gelrite during shoot formation and with agar during rooting, inclusion of 5.0µM benzylaminopurine (BAP) and 0.05 µM naphthaleneacetic acid (NAA) for 2 weeks for shoot induction, and repeated 2.7 µM NAA pulses of 1 week for rooting. Micropropagation success was genotype-dependent. Average multiplication rates varied among experiments from 3 to 15 shoots per embryo. The maximum shoot production from a single embryo was 35. Rooting was the most difficult phase in the propagation process. Most of the plantlets had a plagiotrophic and highly branched growth habit when growing in the greenhouse. Some individuals produced megasporangiate strobili at the age of 3 years and microsporangiate strobili with viable pollen at the age of 4 years. Early-flowering clones and the ability to conserve seedlings from which cotyledons have been cultured give new possibilities for accelerated tree breeding.

Genetic information and ecosystem health: arguments for the application of chaos theory to identify boundary conditions for ecosystem management.

To meet the demands for goods and services of an exponentially growing human population, global ecosystems will come under increasing human management. The hallmark of successful ecosystem management will be long-term ecosystem stability. Ecosystems and the genetic information and processes which underlie interactions of organisms with the environment in populations and communities exhibit behaviors which have nonlinear characteristics. Nonlinear mathematical formulations describing deterministic chaos have been used successfully to model such systems in physics, chemistry, economics, physiology, and epidemiology. This approach can be extended to ecotoxicology and can be used to investigate how changes in genetic information determine the behavior of populations and communities. This article seeks to provide the arguments for such an approach and to give initial direction to the search for the boundary conditions within which lies ecosystem stability. The identification of a theoretical framework for ecotoxicology and the parameters which drive the underlying model is a critical component in the formulation of a prioritized research agenda and appropriate ecosystem management policy and regulation.

Transient expression from microprojectile-mediated DNA transfer in pinus taeda.

Transfer of plasmid DNA to Pinus taeda L. (loblolly pine) cotyledon cells by microprojectile bombardment has been demonstrated using beta-glucuronidase (GUS). GUS histochemical staining indicated active enzyme in localized centers (blue spots) 24 hours after bombardment. GUS expression declined during subsequent culture, but remained detectable in meristematic tissue 62 days post-bombardment, however, transgenic shoots were not recovered. Localized GUS expression events resulted predominantly from single-cell events containing one microprojectile. The staining pattern was complex, with indigo found both in the central target cell and in adjacent cells. Cellular damage sustained by GUS-positive cells ranged from undetectable to sufficiently extensive to cause cell death. Microprojectile bombardment provides a useful method to assay transient gene expression in loblolly pine and has potential for the production of transgenic plants in pine.

Agrobacterium-mediated DNA transfer in sugar pine.

DNA transfer using Agrobacterium tumefaciens has been demonstrated in sugar pine, Pinus lambertiana Dougl. Shoots derived from cytokinin-treated cotyledons formed galls after inoculation with A. tumefaciens strains containing the plasmid pTiBo542. A selectable marker, neomycin phosphotransferase II, conferring resistance to kanamycin, was transferred into sugar pine using a binary armed vector system. Callus proliferated from the galls grew without hormones and in some cases, kanamycin-resistant callus could be cultured. Southern blots provided evidence of physical transfer of T-DNA and the nptII gene. Expression of the nptII gene under control of the nos promoter was demonstrated by neomycin phosphotransferase assays. Several aspects of DNA transfer were similar to those previously observed in angiosperms transformed by A. tumefaciens. This is the first evidence for DNA transfer by Agrobacterium in this species and the first physical evidence for transfer in any pine. These results bring us closer to genetic engineering in this commercially important genus of forest trees.

Extended Host Range of Agrobacterium tumefaciens in the Genus Pinus.

Two-to 4-month-old seedlings of nine pine species (Pinus eldarica Medw., Pinus elliottii Engelm., Pinus jeffreyi Grev. & Balf., Pinus lambertiana Dougl., Pinus ponderosa Laws., Pinus radiata D. Don, Pinus sylvestris L., Pinus taeda L., Pinus virginiana Mill), Douglas fir (Pseudotsuaa menziesii (Mirb.) Franco) and incense cedar (Libocedrus decurrens Torr.) were inoculated with five strains of Agrobacterium tumefaciens. Transformation occurred in all conifer species tested as determined by gall formation and opine production. The frequency of gall formation varied by host species, by bacterial strain, and was related to the age of the stem when inoculated. Galls were visible 8 to 12 weeks after inoculation and were small (often less than 2.5 millimeters in diameter). Fewer than half (230 of 502) of the galls originally formed on the trees were present after 1 year, and 26 of these grew to diameters greater than 2 centimeters. The majority of these larger galls (18 of 26) were found in P. radiata. Bacterial strain-specific opines were found in 67 of the 81 gall tissues sampled.