Responses of isolated balsam-fir stem segments to exogenous ACC, IAA, and IBA.

In this investigation, the effects of exogenous indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), and 1-aminocyclopropane-1-carboxylic acid (ACC) on anatomical development within cultured segments of (L.) Mill. were compared, using debudded and defoliated leaders produced in the preceding year as bioassay material.

The Class II KNOX gene KNAT7 negatively regulates secondary wall formation in Arabidopsis and is functionally conserved in Populus.

• The formation of secondary cell walls in cell types such as tracheary elements and fibers is a defining characteristic of vascular plants. The Arabidopsis transcription factor KNAT7 is a component of a transcription network that regulates secondary cell wall biosynthesis, but its function has remained unclear. • We conducted anatomical, biochemical and molecular phenotypic analyses of Arabidopsis knat7 loss-of-function alleles, KNAT7 over-expression lines and knat7 lines expressing poplar KNAT7.

Carbon content variation in boles of mature sugar maple and giant sequoia.

At present, a carbon (C) content of 50% (w/w) in dry wood is widely accepted as a generic value; however, few wood C measurements have been reported. We used elemental analysis to investigate C content per unit of dry matter and observed that it varied both radially and vertically in boles of two old-growth tree species: sugar maple (Acer saccharum Marsh.) and giant sequoia (Sequoiadendron giganteum (Lindl.

Ultrastructure of vascular cambial cell cytokinesis in pine seedlings preserved by cryofixation and substitution.

Trees depend on the secondary vascular cambium to produce cells for new xylem and phloem. The fusiform cells of this lateral meristem are long and narrow, presenting special challenges for arranging the mitotic spindle and phragmoplast. Fusiform cambial cells of Pinus ponderosa and Pinus contorta were studied by cryofixation and cryosubstitution which preserved ultrastructure and phases of cytokinesis with a resolution not previously attained.

Coniferyl alcohol metabolism in conifers -- II. Coniferyl alcohol and dihydroconiferyl alcohol biosynthesis.

Coniferaldehyde and NADPH when incubated with microsomes isolated from developing xylem of Pinus strobus yielded coniferyl alcohol and dihydroconiferyl alcohol in vitro. D-(+)-Pinitol was also found to be a microsomal constituent. Endogenous E-coniferyl alcohol content, quantified in dormant buds, cambium, bark and needles of Pinus resinosa and P.

Coniferyl alcohol metabolism in conifers -- I. Glucosidic turnover of cinnamyl aldehydes by UDPG: coniferyl alcohol glucosyltransferase from pine cambium.

UDPG: coniferyl alcohol glucosyltransferase (CAGT; EC 2.4.1.

Proteolytic activity in relation to seasonal cambial growth and xylogenesis in Pinus banksiana.

Proteolytic activity in the cambial zone and developing xylem of Pinus banksiana Lamb. was investigated over an annual cycle of growth and dormancy. Highest proteolytic activity was associated with the most active period of primary-wall radial expansion of cambial derivatives, in early spring, before protoplasmic autolysis was initiated in developing earlywood.

Metabolism and excretion of zafirlukast in dogs, rats, and mice.

The in vivo metabolism and excretion of zafirlukast [Accolate; 4, 5-cyclopentoxycarbonylamino-3-[(2-methoxy-4,2- methylphenylsulfonylaminocarbonyl)phenylmethyl]-1-methylindole], a selective peptide leukotriene receptor agonist, were investigated in mice, rats, and dogs. Leukotrienes are a class of compounds that have been identified as being responsible for the contraction of human airway and lung vascular smooth muscle. A chemical agent that is effective in blocking the induced constricting actions of leukotrienes could be used to treat inflammatory processes in the pulmonary system.

Purification of an acidic coniferin-hydrolysing beta-glucosidase from developing xylem of Pinus banksiana.

Two cytosolic, acidic (pI 3.8) glycoproteins (M(r) 110,000 and 90,000) from lignifying xylem of Pinus banksiana were electrophoretically isolated and confirmed by combined gas chromatography-mass spectrometry to be capable of hydrolysing E-coniferin to trans-coniferyl alcohol. These isoenzymes yielded identical N-terminal sequences having negligible homology with documented glucosidases, suggesting that they constitute a novel form of beta-glucosidase.

Electrophoretic analysis of coniferyl alcohol oxidase and related laccases.

Gradient gel electrophoretic methods enabled a distinction to be made between coniferyl alcohol oxidase (CAO) of lignifying cell walls and a pI approximately 9 pine "laccase" recently implicated in lignification (Science 1993 260, 672). Following treatment of a partially purified protein mixture from developing xylem of Pinus strobus with 2-[N-morpholine]ethanesulfonic acid (MES) buffer, isoelectric focusing and sodium dodecyl sulphate-polyacrylamide gel electrophoresis indicated that CAO had been selectively precipitated by MES and thereby purified to electrophoretic homogeneity. Purified CAO was determined to be a cell-wall-bound glycoprotein (38% glycan), M(r) 107,500, pI 7.

Interrater reliability of the Cybex EDI-320 and fluid goniometer in normals and patients with low back pain.

We compared the interrater reliability of the Cybex Electronic Digital Inclinometer-320a (EDI) and the fluid goniometer for measuring lumbar spine range of motion (ROM) in flexion, extension, and prone extension in adults not experiencing back pain and low-back pain patients. We also investigated whether prior palpation training improves reliability of lumbar ROM measurements using these tools. A repeated measures factorial design was used with a 6 x 6 Latin square to balance the order of testing.

A familial syndrome of microcephaly, sparse hair, mental retardation, and seizures.

A family is described in which the father and three of his seven children have microcephaly, mild to moderate mental retardation, and sparse hair. The two affected boys have generalised seizures in addition.

Auxin and ethylene regulation of diameter growth in trees.

Recent studies on the phytohormonal regulation of seasonal cell-division activity in the cambium, primary-wall radial expansion of cambial derivatives, differentiation of xylem cells, and growth of the cortex in forest trees of the north temperate zone are reviewed. Indol-3-ylacetic acid (IAA, auxin) has been characterized by combined gas chromatography-mass spectrometry (GC-MS) in the cambial region of Abies balsamea, Pinus densiflora, Pinus sylvestris and Quercus robur. All of the evidence supports the hypothesis that developing leaves and extending shoots are primary sources of IAA.

Oxygen Isotope Exchange between Metabolites and Water during Biochemical Reactions Leading to Cellulose Synthesis.

Cellulose was produced heterotrophically from different carbon substrates by carrot tissue cultures and Acetobacter xylinum (a cellulose-producing bacterium) and by castor bean seeds germinated in the dark, in each case in the presence of water having known concentration of oxygen-18 ((18)O). We used the relationship between the amount of (18)O in the water and in the cellulose that was synthesized to determine the number and (18)O content of the substrate oxygens that exchanged with water during the reactions leading to cellulose synthesis. Our observations support the hypothesis that oxygen isotope ratios of plant cellulose are determined by isotopic exchange occurring during hydration of carbonyl groups of the intermediates of cellulose synthesis.

The role of plant hormones in higher plant cellular differentiation. I. A critique.

Primary growth and morphogenesis in higher plants can be explained mechanistically in terms of primary types of cellular differentiation, namely, phenomena of cell division, primary wall growth, intercellular bonding and polarity. Plant hormones fulfil essential roles in regulating these types of differentiation, and it is well established that plant hormones can initiate primary growth and morphogenesis. Secondary and terminal types of cellular differentiation largely determine the usefulness of plants to man; however, regulators of these types remain poorly characterized.

The role of plant hormones in higher plant cellular differentiation. II. Experiments with the vascular cambium, and sclereid and tracheid differentiation in the pine, Pinus contorta.

In sterile-cultured explants of stems of the pine Pinus contorta Dougl., fusiform cambial cells differentiated entirely into axial parenchyma cells when exogenous indol-3yl-acetic acid (IAA) was omitted. The normal appearance of the cambial zone was maintained when IAA was included in the medium.

Gas Chromatography-Mass Spectroscopy Identification of 1-Aminocyclopropane-1-carboxylic Acid in Compressionwood Vascular Cambium of Pinus contorta Dougl.

Following cation and anion exchange chromatography, 1-aminocyclopropane-1-carboxylic acid (ACC) was converted to the 2,4-dinitrophenyl derivative and then purified by high-performance liquid chromatography (HPLC). After three HPLC steps, endogenous ACC was identified by GCMS in the vascular cambium on the lower side of Pinus contorta Dougl. ssp.

Non-uniform distribution and seasonal variation of endogenous indol-3yl-acetic acid in the cambial region of Pinus contorta Dougl.

Endogenous, free indol-3yl-acetic acid (IAA) levels were measured in the main stem in the 10-year-old cambial zone, in the adjoining differentiating xylem, and in the adjoining mature xylem of 15-20-year-old Pinus contorta Dougl. by single-ion-current monitoring, combined gas chromatography - mass spectrometry, on several dates from early spring to early winter. Microscopy was used to determine the state of cambial activity on each harvest date.

A tracheid-differentiation factor from pine needles.

Exogenous indol-3yl-acetic acid (IAA), alone and together with several cytokinins, was ineffective in promoting the complete differentiation into tracheids of cambial derivatives of Pinus contorta Dougl.; IAA alone promoted cambial cell division and primary-wall growth in cambial derivatives throughout the stem's length. In contrast, a single pair of needles on a stem cutting in light promoted neither cambial cell division nor primary-wall growth in cambial derivatives but did promote complete differentiation of cambial cells into tracheids; tracheids differentiated only near the junction of the foliated short shoot with the stem.