Quantitative proteome analyses of meristematic and nonmeristematic tissues from Medicago truncatula primary and lateral roots and meristem tissues from plants treated with acetohydroxyacid synthase-inhibiting herbicides were made. The accumulation of 81 protein spots changed in meristematic and nonmeristematic tissues and 51 protein spots showed significant changes in accumulation in herbicide-treated meristems. Identified proteins indicate two trends, (i) increased accumulation of cell division and redox-mediating proteins in meristems compared to nonmeristematic tissues and (ii) increased accumulation of pathogenesis-related and decreased accumulation of metabolic proteins in herbicide-treated roots.

A non‐colony‐forming axenic strain of Phaeocystis globosa (Harlot) Lagerheim was shown to produce a water‐soluble β‐d‐glucan. This glucan consisted of about 20 glucose units, mainly (l→3)‐linked, with branching at position 6. Therefore, it can be classified as a chrysolaminaran. Glucan production occurred mainly during the stationary growth phase and resulted in concentrations as high as 76 pg glucose per cell. When cultures were deprived of light the glucans were consumed, which supports their possible role as compounds used for temporary storage of energy.

Seeds of genetically modified (GM) peas (Pisum sativum L.) expressing the gene for alpha-amylase inhibitor-1 (alphaAI1) from the common bean (Phaseolus vulgaris L. cv. Tendergreen) exhibit resistance to the pea weevil (Bruchus pisorum). A proteomic analysis was carried out to compare seeds from GM pea lines expressing the bean alphaAI1 protein and the corresponding alphaAI1-free segregating lines and non-GM parental line to identify unintended alterations to the proteome of GM peas due to the introduction of the gene for alphaAI1. Proteomic analysis showed that in addition to the presence of alphaAI1, 33 other proteins were differentially accumulated in the alphaAI1-expressing GM lines compared with their non-GM parental line and these were grouped into five expression classes. Among these 33 proteins, only three were found to be associated with the expression of alphaAI1 in the GM pea lines. The accumulation of the remaining 30 proteins appears to be associated with Agrobacterium-mediated transformation events. Sixteen proteins were identified after MALDI-TOF-TOF analysis. About 56% of the identified proteins with altered accumulation in the GM pea were storage proteins including legumin, vicilin or convicilin, phaseolin, cupin and valosin-containing protein. Two proteins were uniquely expressed in the alphaAI1-expressing GM lines and one new protein was present in both the alphaAI1-expressing GM lines and their alphaAI1-free segregating lines, suggesting that both transgenesis and transformation events led to demonstrable changes in the proteomes of the GM lines tested.

Characteristics of the toroidal relaxed state of reversed field pinches and comparison with experimental results Phys.

The distribution of free and ester-linked indole-3-acetic acid (IAA) in the vascular stele and cortex-epidermis of the Zea mays mesocotyl was measured by gas chromatography-selected ion monitoring-mass spectrometry and by radioimmunoassay with good agreement between the two assay methods. On a per plant basis, 72% of the free IAA was found in the stele and 28% was in the cortex, whereas 80% of the ester IAA was in the cortex with 20% localized in the stele. On a fresh weight basis, the concentration of free IAA was 15 to 28 times higher in the stele than in the cortex, whereas the concentration of ester IAA was similar in the two tissues. The concentration of free IAA in the apical portion of the cortex was 3 times higher than in the basal portion, and this distribution correlated with the relative growth rates of the apical and basal portions of the mesocotyl. No changes in the longitudinal distribution of ester IAA were found in either the cortex or stele.The growth of etiolated shoots of higher plants results primarily from cell enlargement. Inasmuch as IAA is believed to regulate cell enlargement in etiolated shoots, it is important to determine how the distribution of IAA correlates with growth. Early studies with tissue segments of A vena have shown that growing zones in the apex contain more auxin than slower growing zones toward the base (12, cJf 13). However, recent studies with young Zea mays roots have shown that most of the IAA is localized in the vascular stele, whereas the surrounding cortex-epidermis contains very low levels (3, 4). If such radial gradients prove to be a common feature of plants, then the early studies of longitudinal auxin distribution using tissue segments must be reexamined.In this paper, we show using GC-SIM-MS4 (6) and a RIA (10) validated by GC-SIM-MS (9) ' To whom reprint requests should be directed. 4 Abbreviations: GC-SIM-MS, gas chromatography-selected ion monitoring-mass spectrometry; RIA, radioimmunoassay; d4-1AA, 4,5,6,7-tetradeutero-indole-3-acetic-acid; PBS, phosphate-buffered saline.precursor of IAA (1) Growth Studies. The relative growth rates in different regions of the mesocotyl were estimated by the ink-marking method. The mesocotyl was marked with India ink at 2-mm intervals, plants were grown for 8 h, and the distance between marks was then measured using a dissecting microscope with an ocular micrometer. Owing to variation in initial plant size, the initial length of each mesocotyl was arbitrarily set equal to 100 units beginning at the coleoptile and ending at the seed (Fig. 1). The position of each segment delimited by ink spots was calculated based on its location at the beginning of the experiment. The data reported in Figure 1 represents 25 plants pooled from three separate experiments.Tissue Extraction. The vascular stele and cortical portions of the mesocotyl were separated and immersed in acetone at -78°C. In experiments using GC-SIM-MS, the vascular stele was separated from the cortex after cutting off the coleoptile at a point I to 2 mm b...