Atsumi Shimada

βγ-Dehydrocurvularin and Related Compounds as Nematicides of Pratylenchus penetrans from the Fungus Aspergillus sp.

The new nematicidal compound, βγ-dehydrocurvularin (1), together with three known compounds, αβ-dehydrocurvularin (2), 8-β-hydroxy-7-oxocurvularin (3) and 7-oxocurvularin (4), were isolated from the culture filtrate and mycelial mats of Aspergillus sp. The structures of 1-4 were established by spectroscopic methods including 2D NMR. The biological activities of 1-4 were examined by bioassays with root-lesion nematodes, and lettuce and rice seedlings.

Chloroisosulochrin, Chloroisosulochrin Dehydrate, And Pestheic Acid, Plant Growth Regulators, Produced By Pestalotiopsis Theae

New plant growth regulators, named chloroisosulochrin, chloroisosulochrin dehydrate and pestheic acid, have been isolated from the culture filtrate of Pestalotiopsis theae grown on a Raulin-Thom medium. Their structures have been established by spectroscopic and chemical methods. The biological activities of these compounds have been examined using bioassay methods with lettuce and rice seedlings

Penipratynolene, a novel nematicide from penicillium bilaiae Chalabuda.

New acetylenic nematicidal compound, penipratynolene (1), methy (2′R)-4-(2′-hydroxy-3′-butynoxy)benzoate, together with two known compounds, 6-methoxycarbonylpicolinic acid (2) and 2,6-pyridinedicarboxylic acid (3), were isolated from the culture filtrate of Penicillium bilaiae Chalabuda. The structures of 1–3 were established by spectroscopic methods. The absolute configuration of 1 was confirmed by using a modified version of Mosher’s method. Compounds 1–3 showed nematicidal activity of 77%, 52%, and 98%, respectively, by a bioassay at 300 mg/l with the root-lesion nematode Pratylenchus penetrans.

Aspterric Acid and 6-Hydroxymellein, Inhibitors of Pollen Development in Arabidopsis thaliana, Produced by Aspergillus terreus

Aspterric acid (1) and 6-hydroxymellein (2), inhibitors of pollen development in Arabidopsis thaliana, have been isolated fromthe fungus Aspergillus terreus. 1 and 2 inhibited the pollen development at concentrations of 38 and 52 μᴍ, respectively. The microscopic examination of pollen development suggested that the inhibition by the treatment with 1 caused at meiosis and the inhibition by the treatment with 2 caused at microspore stage. 1 and 2 could be useful agents for the molecular investigation of anther and pollen development in higher plants.

Peniamidienone and penidilamine, plant growth regulators produced by the fungus Penicillium sp. no. 13

Peniamidienone and penidilamine were isolated from cultures of the fungus Penicillium sp. No. 13 as new plant growth regulators and their structures were established by NMR spectroscopic studies. Peniamidienone showed weak inhibition of lettuce seedling growth.

4-Hydroxykigelin and 6-Demethylkigelin, Root Growth Promoters, Produced by Aspergillus terreus

Root growth promoters, 4-hydroxykigelin (1) and 6-demethylkigelin (2), together with 6- hydroxymellein (3) were isolated from cultures of the fungus Aspergillus terreus and their structures were identified by spectroscopic analysis. The biological activities of the three dihydroisocoumarins, 1, 2, and 3, have been examined using a bioassay method with lettuce seedlings. Furthermore, interactions between the dihydroisocoumarins and indole-3-acetic acid against the root growth have been examined.

Interaction between aspterric acid and indole-3-acetic acid on reproductive growth in Arabidopsis thaliana.

Application of indole-3-acetic acid (IAA) with a pollen growth inhibitor, aspterric acid (AA), results in the recovery of normal pollen development. In contrast, application of gibberellin (GA3) with AA do not induce normal pollen growth. In addition, application of different concentrations of IAA with AA shortens the period of growth from bolting to first flowering as compared to that treated with AA alone. Furthermore, stem length and number of flower bud treated with IAA and AA were similar to those of control. These results suggest, that IAA may play an important role in reproductive growth of A. thaliana.

Influence of Glyphosate on Flower Morphogenesis and Pigmentation in Petunia hybrida

Glyphosate showed a remarkable effect inducing the change of flower symmetry from the actinomorphic to the zygomorphic type in Petunia hybrida. Glyphosate [N-(phosphonomethyl) glycine] reduced the anthocyanin content and showed a weak inhibitory effect against phenylalanine ammonia-lyase (PAL) activity. ʟ-2-Aminooxy-3-phenylpropionic acid (APA), an inhibitor of PAL activity, reduced the anthocyanin content but had no effect on flower shape. Additional phenylalanine or trans-cinnamic acid, the intermediates of glyphosate inhibition against PAL activity, could not recover the change of flower shape induced by glyphosate. These results suggested that the reduction of PAL activity alone could not account for the two characteristic changes of flower symmetry and pigmentation induced by glyphosate. On the other hand, the results of application of glyphosate-related compounds suggested that the structure of glyphosate contributed to induce the morphological change of Petunia flower. Glyphosate may thus be a very useful agent in the elucidation of unresolved questions of flower morphogenesis and the related metabolism.

Pollen growth regulator, fusanolide A, and a related metabolite from Fusarium sp.

Fusanolides A (1) and B (2) were isolated from cultures of the fungus Fusarium sp. as pollen growth regulators and their structures were established by spectroscopic evidence. 1 completely inhibited pine pollen germination and tea pollen tube growth at a concentration of 300 mg/l, but 2 showed no inhibitory effect on them at the same concentration.

Notizen: Deoxycyclopaldic Acid and Cyclopaldic Acid, Plant Growth Regulators, Produced by Penicillium sp.

Deoxycyclopaldic acid (1) and cyclopaldic acid (2) were isolated from cultures of the fungus Penicillium sp. as plant growth regulators and their structures were established by spectroscopic evidence. Deoxycyclopaldic acid was found in nature for the first time. The biological activities of 1 and 2 have been examined using bioassay methods with lettuce and rice seedlings.