Sacculatane diterpenoids from axenic cultures of the liverwort Fossombronia wondraczekii

Five new sacculatane diterpenoids, 17,18-epoxy-7-sacculaten-12,11-olide, 7,17-sacculatadien-11,12-olide, 11beta,12-epoxy-7,17-sacculatadien-11alpha-ol, 1beta-acetoxy-11beta,12-epoxy-7,17-sacculatadien-11alpha-ol and 1beta,15xi-diacetoxy-11,12-epoxy-8(12),9(11),17-sacculatatriene along with sacculatal and sacculatanolide have been isolated from axenic cultures of the liverwort Fossombronia wondraczekii and their structures assigned on the basis of their spectroscopical properties.     

Biosynthesis of a hopane triterpene and three diterpenes in the liverwort Fossombronia alaskana.

The biosynthesis of the triterpene 22-(30)-hopene-29-acid and the diterpenes 7,17-sacculatadiene-11,12-dial (sacculatal), trans-phytol and a new neoverrucosane-type diterpenoid (5-oxo-neoverrucos-(13)-ene) was studied by incorporation of [1-13C]-labelled glucose into axenic cultures of the artic liverwort Fossombronia alaskana. Quantitative 13C NMR spectroscopic analysis of the resulting labelling patterns showed that the isoprene units of the triterpene are derived from the mevalonic acid pathway, whereas the isoprene units of the diterpenes are built up via the methylerythritol phosphate pathway.     

Biosynthesis of a neo-epi-verrucosane diterpene in the liverwort Fossombronia alaskana. A retrobiosynthetic NMR study

The biosynthesis of the diterpene 8alpha-acetoxy-13alpha-hydroxy-5-oxo-13-epi- neoverrucosane in the arctic liverwort Fossombronia alaskana was studied by incorporation experiments using [1-(13)C]- and [U-(13)C(6)]glucose as precursors. The (13)C-labeling patterns of acetyl-CoA, pyruvate, and phosphoenolpyruvate in intermediary metabolism were reconstructed from the (13)C NMR data of biosynthetic amino acids (leucine, alanine, phenylalanine) and were used to predict hypothetical labeling patterns for isopentenyl pyrophosphate formed via the mevalonate pathway and the deoxyxylulose pathway. The labeling patterns observed for the neoverrucosane diterpene were consistent with the intermediate formation of geranyllinaloyl pyrophosphate assembled from dimethylallyl pyrophosphate and three molecules of isopentenyl pyrophosphate generated predominantly or entirely via 1-deoxyxylulose 5-phosphate. The experimental data can be integrated into a detailed biosynthetic scheme involving a 1,5-hydride shift. The postulated involvement of the 1,5-hydride shift was confirmed by an incorporation experiment with [6,6-(2)H(2)]glucose.     

Spore morphology and wall ultrastructure of Trachypteris species (Pteridaceae)

Trachypteris is a small genus consisting of four species native to America and Madagascar: Trachypteris induta, T.?pinnata, T.?gilliana, and T.?drakeana. The spores of the genus were studied using light microscopy and scanning and transmission electron microscopy. They are trilete, triangular to globose, with equatorial diameter of 29?C58???m and polar diameter of 26?C53???m. The exospore is 0.5?C1.1???m thick, plane, and two-layered. The perispore is 0.3?C6.8???m thick and two-layered. Depending on the species, two different ornamentations were observed: cristated with partially fused cristae, and ridged with partially fused ridges, forming an incomplete reticulum. Globules immersed in the perispore were occasionally observed. The systematic value of the Trachypteris spores is discussed, and their morphology and ultrastructure are compared with those of other related cheilanthoid ferns. The palynological characteristics presented here may be useful for phylogenetic studies within the Pteridaceae, and particularly within the cheilanthoid ferns.     

Spore morphology and wall ultrastructure of Hymenophyllaceae Link (Pteridophyta) from north-west Argentina

The family Hymenophyllaceae is represented in the study area by six species in two genera, Hymenophyllum J. E. Smith and Trichomanes L. The study was based on herbarium material and spores were studied under light microscope (LM), scanning electron microscope (SEM) and transmission electron microscope (TEM). Both genera have trilete spores, 23 to 45 μm in equatorial diameter, with an ornamentation of echinulae and cones in Hymenophyllum and of verrucae, gemmae and granules in Trichomanes. Mature spores have a sporoderm composed of a perispore, an exospore and a fibrillar endospore; the exospore is 0.5 to 2.5 μm thick, compact and with an irregular margin. In some cases radial channels and other channels associated with the middle and inner parts of the laesurae were evident. A series of cavities filled with an opaque content line the inner margin of the exospore. The perispore is 20 to 400 nm thick and unevenly differentiated along the surface of a same spore. Under TEM, two main differentially contrasted portions could be distinguished: a dark massive portion with structural components could not be distinguished, and a light portion with several plates arranged in piles. The inner surface of the perispore exhibit short scales. Globules are immersed within the perispore at some depth from the perispore surface and others connected to it by structural threads. The spore characters observed including shape, ornamentation, laesurae length and wall structure are useful in distinguishing the two genera studied, but less useful in differentiation at the species level.     

Spore morphology of the genus Dryopteris Adans. (Dryopteridaceae) in Korea

Spore morphology of the Korean members of the genus Dryopteris was examined by scanning electron microscopy. In particular, spores of D. hangchowensis, D. woodsiisora, D. saxifragivaria, and D. subexaltata were examined here for the first time. Three perispore types were recognized on the basis of the shape of macro-ornamentations on perispore: these include rugate, echinate, and spinose. The rugate perispore type appeared to be the most common in the genus, and probably represents plesiomorphic condition in the genus Dryopteris. The echinate perispore type is found in D. expansa, and spinose perispore type in D. formosana. The results of this study demonstrate that the perispore characteristics, particularly the shape of macro-ornamentation and surface texture, have diagnostic value at the species level. Indeed, most of the Dryopteris taxa in Korea could be distinguished by their perispore characters. In addition, spores of sexual diploid individuals of D. saxifraga were much smaller than those of agamosporous triploid individuals, supporting the contention that the size of spores in ferns is generally related to ploidy levels.     

Spore morphology of the north Asian members of Cystopteridaceae

Spores of Cystopteridaceae from northern Asia were examined using scanning electron microscopy. To evaluate the utility of spore morphology in the taxonomy of each genus, we examined spores of 14 species: seven species each of Gymnocarpium and Cystopteris. Among these are 12 species occurring in northern Asia and two species from other regions for comparative studies. The study focused particularly on perispore characters and spore size. Spores of all species examined are monolete, bean-shaped, with a range in spore size of 26–56 × 18–37 μm for Cystopteris and 25–48 × 16–34 μm for Gymnocarpium. The perispore is morphologically diverse within Cystopteris, but less so within Gymnocarpium. The perispore of the Cystopteris spores is characterised by folds and spines that are separate or form complex sculptural elements. Sacci, ridges and flanges, sometimes on the same spore, are characteristic of the perispore of Gymnocarpium. Spores have straight laesura over which the perispore forms a crest. The crest represents a high and flat fold, which is entire, foveolate or reticulate.     

Spore morphology of some Brachytheciaceae Schimp. species (Bryophyta) from Turkey

The spores of Homalothecium sericeum (Hedw.) Schimp., Brachythecium populeum (Hedw.) Schimp., B. velutinum (Hedw.) Schimp. var. salicinum (Schimp.) Mönk., B. velutinum (Hedw.) Schimp. var. validum C. Jens. and Eurhynchium hians (Hedw.) Sande Lac. were studied by light and scanning electron microscopy for the first time. The apertural region consists of a leptoma in all spores. Two spore types, characterized by their surface ornamentation, are established, reflecting the species taxonomic relationships. While the surface ornamentation is of the insuloid type in Eurhynchium hians, it consists of a granuloid type in Homalothecium sericeum , Brachythecium populeum , B. velutinum . var. salicinum, B. velutinum var. validum. The spore wall of the family Brachyteciaceae includes sclerine (the dinstinction between exine and perine may be difficult to define) and intine. The taxonomy of the genera Brachytecium and are discussed on the basis of their spore morphology.     

Spore morphology and some other features of Goniomitrium Hook. & Wils. (Funariaceae)

Abstract

Goniomitrium enerve, G. acuminatum and G. africanum are distinguished mainly on costal features. There are some problems with the Australian species because of intergradation of characters but no name changes have been suggested and a key to species is provided. The spores of the three species, which are monolete and have a large reticulate ornamentation, are distinctive amongst moss spores and appear to be diagnostic for the genus.     

The Localization of Lead in the Lichen Ramalina duriaei (De Not.) Bagl.

In an attempt to ascertain whether the lichen Ramalina duriaei could be employed to biomonitor atmospheric lead pollution, specimens of this lichen were exposed to Pb (NO₃)₂ solutions and a buffered solution (tartaric acid/sodium bitartrate, pH 2.8) of sodium rhodizonate (C₆O₆Na₂) was used to locate lead in their thalli. The procedure entailed exposure of the lichen to 0, 5, 50 and 100 ppm Pb for 5 min and 1 h and the subsequent determination of the lead contents from photographs of the thalli. Distribution of lead in different parts of the thallus was assessed after exposure of the lichens to 2 ppm Pb (9 h or three d), 50 ppm (45 min) or 200 ppm (4d). Cross sections of vegetative parts of the thallus and of the apothecia revealed that lead penetrated into the cortical cells of the thallus but not into the algal cells of the phycobiont nor the ascospores or medullary cells. The observed massive penetration of lead into cortical cells supports the notion that Ramalina duriaei is sensitive to atmospheric lead pollution.     

Spore morphology of Serpocaulon A.R.Sm. and related taxa from Brazil (Polypodiaceae)

The epiphytic fern genus Serpocaulon (Polypodiaceae) comprises 42 species nested within the neotropical clade of the family together with genera such as Campyloneurum, Grammitis, Microgramma, Niphidium, Pleopeltis, Pecluma, Polypodium and Terpsichore. Although Serpocaulon is a well-supported genus, its intra-specific relationships are still not completely resolved. The morphological dataset for Serpocaulon and related genera is therefore expanded here with information on spore morphology to provide additional information for phylogenetic consideration. Spores have been collected from herbarium vouchers and acetolysed for light and scanning electron microscopy. All members of the neotropical clade have monolete spores, except for Grammitis and Terpsichore, which have trilete spores. Both verrucate and papillate ornamentation types are recognised. The palynological analysis shows close similarity between spores of Serpocaulon, Campyloneurum, Pleopeltis and Polypodium and supports close phylogenetic relationships between these taxa. Species of the grammitid clade, although nested within the Polypodiaceae, have spore morphology that supports a separate position.     

Hyphal wall peptides and colonial morphology in Neurospora crassa

The peptides of the hyphal wall of 23 colonial strains of Neurospora crassa have been compared, both quantitatively and qualitatively, to those of three wild-type strains. We found that all colonial strains examined have a reduced quantity of peptide, ranging from 6.64% to 3.34% of the dry weight of the wall, compared to the wild-type average of 9.35%. The peptides from the walls of all colonial strains except doily eluted from DEAE-cellulose with the same pattern as those from wild-type walls. The aberrant peptides from doily walls did not bind to DEAE-cellulose, suggesting a reduction in the number of acidic residues in these peptides. Although a causal connection between colonial morphology and reduced peptide is not shown, we consider the quantity of peptide in the hyphal wall to be an important determinant in the control of normal morphology and growth.This work was supported by a grant from the National Institutes of Health, GM-16224.     

Spore Discharge in the Basidiomycetes: I. Periodicity of Spore Discharge by Trametes gibbosa Fr.

Variations in the rates of spore discharge from this fungushave been examined in controlled laboratory conditions, usingapparatus designed to make a continuous record of the numbersof spores discharged by a strip of hymenium measuring approximately4.5 cm. X o.1 cm. These records have been extended by a directmicroscopic study of the numbers of spores falling through asmall area below the hymenium during successive short periods. Analysis of the continuous record has shown that at any onetime the rate of spore discharge is not uniform over the wholehymenium, and that at any one site it ia not constant. The variationin the rate of discharge in any one site is rhythmical, withintervals of the order of 30 to 90 minutes between maxima. Thesmall linear areas of hymenium which have been examined haveshown nearly the same rhythm-overall, but the phase of thisrhythm has differed at different sites in the area.     

Cell wall-associated peroxidase in cultured cells of liverwort,Marchantia polymorpha L. Changes of peroxidase level and its localization in the cell wall

Most of the peroxidase activities from cultured cells of Marchantia polymorpha L. were found in the cell wall. The activities increased markedly after the beginning of stationary growth. Cytochemical examination using an electron microscope indicated that the peroxidase was localized in the layers of the cell wall. The increase of peroxidase released from the cells into the culture medium was closely correlated with the increase of the peroxidase level in the cell wall. The release of peroxidase seemed to be caused by fragmentation of the cell wall stripped from cell.