Diphaladine A，扁枝石松中一个新的石松生物碱

从扁枝石松（Diphasiastrum complanatum）的95％乙醇提取物中分离得到1个新的石松生物碱,经波谱技术鉴定其结构,命名为diphaladine A（1）。同时还分离得到其它9个已知石松生物碱类化合物,其中obsctmmaine A（2）,L20,lycoposerramine—K,des—N—methyl—β—obscurine,des-N—methyl-α—obscurine,lycoflexion,和phlegmariurine B等7个化合物均为首次从该植物中分离得到。     

Ultrastructural studies of mutant spermatozoids in ferns. I. The mature nonmotile spermatozoid of mutation 230X in Ceratopteris thalictroides(L.)Brongn

Electron microscopy reveals that nonmotility in the spermatozoids of mutant 230X of the fern Ceratopteris thalictroides results from highly aberrant flagella. With respect to its mitochondrial complement, amyloplasts, condensed chromatin within the nucleus and the multilayered structure (MLS), the mutation is almost indistinguishable from the wild-type spermatozoids. In contrast to flagellar mutations in other organisms (man, mouse, Drosophila, Chlamydomonas), which principally affect the microtubules of the axoneme, the basal body cartwheel is lacking in 230X. In its absence, compound microtubules with shared walls are still present, but in highly disorganized arrays. Since the amount of polymerized tubulin in the spermatozoids of 230X is approximately the same as in the wild type, the mutation does not seem to affect microtubule synthesis or assembly. Centriolar cartwheels appear to be essential templates for the alignment of triplet and doublet tubules in regular radial arrays. The MLS in 230X is almost normal, whereas the flagella are aberrant, indicating that there are two distinct functional classes of microtubules in archegoniate spermatozoids. In contrast to the helix of 3½ gyres found in the wild type, nuclear morphology in 230X exhibits profound distortions ranging from deep channels and holes to supernumerary attenuated arms. Parts of nuclei associated with the MLS are almost normal, but malformations are in variably associated with the presence of microtubules of the aberrant flagella that are in close proximity t o the nuclear surface. The shapes of the teratologies are directly related to the number and configuration of the adjacent perinuclear tubules. From these findings, it is argued that microtubules have a crucial role in nuclear shaping in archegoniates; and that the precise form of the nucleus is closely related to the geometry and development of the MLS. On the other hand, it is difficult to envisage how microtubules growing in the chaotic arrays found in 230X could themselves generate shaping forces, More likely, the actual force-generating system, situated in or near the nuclear envelope, has become misaligned and severely restricted by the perinuclear arrays of flagellar tubules, which function as cytoskeletal elements additional to those of the normal MLS. Archegoniate plants are particularly advantageous for the detection of basal body mutants, since centrioles are absent from the mitotic apparatus. Cytological and hybridization studies of 230X affirm the nuclear basis of the mutation, and provide no support for the possible genetic autonomy of centrioles.     

Ultrastructure and phylogeny of the spermatozoid ofChara vulgaris (Charophyceae)

At maturity, spermatozoids of the green algaChara vulgaris are biflagellated, contain little cytoplasm, and coil for approximately 2 1/2 gyres within the mother cell wall. The anterior of the cell contains an ovoid headpiece anchoring two slightly staggered basal bodies that are positioned above and directly in front of approximately 30 linearly arranged mitochondria. An elongated stellate pattern occupies the transition zone between the BBs and axonemes. Flagella emerge from the cell just in front of the nucleus and encircle the full length of the spermatozoid. The spline comprises a maximum of 38 microtubules surrounding the anterior mitochondria and gradually decreases posteriorly to a minimum of 11. The dense nucleus is narrow, cylindrical, and occupies the central revolution of the cell. Six starch-laden plastids and associated mitochondria are linearly arranged at the cell posterior. Phylogenetic analyses of charalean taxa and archegoniates based on spermatogenesis strongly support the orderCharales, withNitella as the sister group toChara. Diagnostic features ofChara spermatozoids include absence of a lamellar strip and axonemes embedded in the cell for almost the entire length of the anterior mitochondria. Potential relationships amongCharales, Coleochaetales and archegoniates are evaluated in regards to the probable course of evolution of streamlined biflagellated gametes.     

Vascular architecture in shoots of early divergent vascular plants, Lycopodium clavatum and Lycopodium annotinum

Lycopodium represents a phylogenetically distinct clade of basal vascular plants with anatomical characters that have no parallel in other lineages. Thus, knowledge of lycopod structure and development may reveal important information about the common ancestors of all vascular plants. Here we report the unique architecture of the conducting system in Lycopodium annotinum and Lycopodium clavatum. Based on multiple series of anatomical sections, we reconstructed spatial relationships between microphylls and the stelar system. Analysis revealed that protoxylem ribs (PXR) were vertical, regardless of type of phyllotaxis, and their numbers were variable. Microphyll traces (MTr) were randomly distributed between ribs, resulting in the absence of defined sympodia and varied lengths of MTr. Dichotomous branching contributed to additional features, for example occurrence of mesarch protoxylem, affecting stele structure and PXR numbers. Our data showed limited interrelationships between lycopod vasculature and microphyll phyllotaxis. This may suggest that both systems developed independently, then evolved together to form the integrated supply system. Thus vasculature in extant lycophytes may be less functionally efficient than in seed plants, where consistent leaf-trace lengths guarantee predictable energy utilization during ontogeny. Differences may result from the phylogenetically different origin of microphylls, and the level of vascular complexity.     

Ultrastructure of the spermatozoid in Halimeda tuna (chlorophyceae)

The mature Halimeda tuna spermatozoid was studied under the electron microscope. It is pear-shaped and biflagellate. The nucleus is an uncondensed structure except for a few opaque (chromatin) aggregations and shows a rounded profile. The endoplasmic reticulum is a rather well-developed system of rough cisternae engaged in synthesis and storage of proteins. Free ribosomes are numerous. A large mitochondrial apparatus shaped like a horseshoe lies in the anterior gamete region. Only one single plastid is found, and it exhibits a deeply indented outline, a partially structured matrix, osmiophilic globules, and three to four starch grains. The axoneme pattern is 9 + 2. B tubules show septate lumina. A peculiar structure provided with a three-layered shell covering materials of varying electrondensity lies on the upper surface of both basal bodies. The flagellar root system exhibits a cruciate pattern and sets having an inconstant number of microtubules – ie, three, four, or five.     

Isolation and characterization of microsatellite loci of Lycopodium fordii Bak. (Lycopodiaceae, Pteridophyta)

Lycopodium fordii Bak. (Lycopodiaceae, Pteridophyta) is a gardening plant with a native, fragmentary distribution in Taiwan. In this study, we described the development of eleven microsatellite loci in L. fordii for genetic studies. These new markers were tested in 16 individuals of three populations. The number of alleles ranged from 1 to 5 and the expected heterozygosity from 0.41746 to 0.72222. Four of the nine polymorphic loci were significantly deviated from Hardy-Weinberg expectations due to the heterozygote deficiency. The microsatellite markers have also been proved as informative genetic markers for other 15 Lycopodium species.     

Observations on phyllotaxis, stelar morphology, the shoot apex and gemmae of Lycopodium lucidulum Michaux (Lycopodiaceae)

Phyllotaxis in Lycopodium lucidulum consists of low alternating spirals, with the adult shoots corresponding to a system of 5 + 5 contact parastichies in which there are ten orthostichies. Each major stelar lobe is a sympodium of the leaf traces of two orthostichies and each lobe has two mesarch xylem poles, Differentiation of both the procambium and xylem of the leaf traces is bidirectional, that is differentiation first commences in the leaf base and then is acropetal into the leaf and basipetal into the stem. Furthermore, the procambium of the axis does not extend above that of the youngest leaf primordium and the axial procambium is in part a composite of that of the leaf traces. Thus, it is concluded that the stele in this taxon is not a strictly cauline structure. The shoot apex consists of four zones—a zone of surface initials, a zone of subsurface initials, a peripheral zone and a rib meristem. This zonation pattern is essentially the same as that of the seed plants. From their inception, gemma primordia also exhibit shoot apical zonation and are entirely different from leaves in their subsequent growth pattern and vascularization. Although the gemmae occupy leaf sites in the phyllotactic sequence, they are interpreted as arrested stem dichotomies on the basis of their development and vascular system.     

Ultrastructure of the spermatozoid of Centrorhynchus milvus Ward 1956 (Paleacanthocephala, Polymorphidae)]

The Centrorhynchus milvus spermatozoon is a filiform cell. The free part of the flagellum measure 2 mu and is situated in front of the gamete. The centriole is no more visible but an axial tubule formation is found at the anterior extremity of the flagellum. This Polymorphidae spermatozoon shows a reversed anatomy like the one we described for the first time with an acanthocephala wich belongs to the Rhadinorhynchidae family.     

Ultrastructure of Euglena anabaena var. minor (Euglenophyceae)

The freshwater green euglenoid Euglena anabaena var. minor has a pellicle with groove‐ridge articulation, a chloroplast with pyrenoids doubly sheathed by two paramylon caps, and a nucleus with permanently condensed chromosomes and nucleolus. The flagellar apparatus basically resembles that of Euglena. The dorsal root (DR) originates at the dorsal basal body of the emergent flagellum, while both the intermediate root (IR) and ventral root (VR) originate at the ventral basal body of the non‐emergent flagellum. The cytoplasmic pocket is associated with the ventral root/ reinforcing microtubular band. However, ultrastructural characterization of E. anabaena var. minor shows the pocket to consist of five to seven microtubules, and flagellar roots with microtubule configuration of 3–4–6 in the DR‐IR‐VR. The dorsal band microtubules pair at the reservoir‐canal transition level. The doublet microtubules are formed into triplets and doublets at the lower canal level and then make pellicular microtubules at the upper canal level.     

Ultrastructure of sperms in Acoela (Acoelomorpha) and its concordance with molecular systematics

Abstract. The sperms of the Acoela, a group of lower worms, are filiform cells with 2 flagella incorporated into the cell body. Their axonemes can variously have 9+2, 9+1, or 9+0 patterns of microtubules; and singlet microtubules in the cell body can be arranged in axial or cortical positions. An analysis of phylogenetic relationships of acoels based on molecular characters (18S rDNA sequence data) showed that these patterns of microtubules, where known, fell into discrete monophyletic groups. To test this hypothesis, we have expanded the database of sperm characters by examining the ultrastructure of a further 10 species representing 4 acoel families. As expected, the Convolutidae fell into 2 unrelated groups: “small‐bodied convolutids”(Convoluta pulchra, Praeconvoluta tigrina, Pseudaphanostoma smithrii) having 9+2 axonemes and cortical microtubules, and “large‐bodied convolutids” (including Wulguru cuspidata) having 9+0 axonemes and axial microtubules. Also, as expected, a member of the Mecynostomidae (Paedomecynostomum bruneum) has 9+1 axonemes and axial microtubules. Members of a family that appears intermediate by molecular characters, the Otocelididae, significantly have a variety of patterns: axonemes with both 9+2 and 9+0 patterns (Notocelis gullmarensis) or just 9+2 (the other species), and either axial (Philocelis brueggemanni), both axial and cortical (N. gullmarensis) microtubules, or microtubules that bend between axial and cortical positions along the length of the sperm (Otocelis sandara). Members of the Dakuidae (Daku woorimensis) also belong to this intermediate group, having 9+2 axonemes and axial microtubules, while in a fifth otocelidid (Stomatricha hochbergi), sperm characters are like those of the “large‐bodied convolutids” (9+0 axonemes and axial microtubules). Characters of sperm morphology generally support the molecular hypothesis of relationships and confirm a suspected polyphyly of the families Convolutidae, Otocelididae, and Actinoposthiidae.     

Ultrastructure and tubulin immunocytochemistry of the copulatory stylet-like structure in Childia species (Acoela)

One of the main characters used in acoel taxonomy is the male copulatory organ. Despite this, ultrastructural studies of this structure are scarce. We studied the ultrastructure of the copulatory organ in eight species of acoels belonging to the taxon Childia. Members of Childia possess a well-developed conical or cylindrical stylet-like structure composed of needles. Immunogold cytochemistry of tubulin was used to determine the composition of the needles. Stylet-like structures of Childia species at the ultrastructural level are basically similar. Stylet needles show intracellular differentiations. As shown both by ultrastructural and immunocytochemical methods, the stylet needles, in all species studied, are composed of long, parallel microtubules, either tightly packed or polymerized. We report unusual polymerization of microtubules, resulting in formation of a honeycomb-like structure in cross section. Variations of ultrastructure among Childia species include numbers and arrangement of stylet needles, shape of needles, needle compactness, microtubule polymerization, direction of stylet growth, and presence/absence of different types of granules. The stylet-like structures are homologous within Childia, but are likely to prove nonhomologous with the other needle-like structures found in acoel copulatory organs. Stylets in Platyhelminthes are not homologous with stylet-like structures in acoels.     

Ultrastructure of Trimastix pyriformis (Klebs) Bernard et al.: similarities of Trimastix species with retortamonad and jakobid flagellates.

Trimastix pyriformis (Klebs 1893) Bernard et al. 1999, is a quadriflagellate, free-living, bacterivorous heterotrophic nanoflagellate from anoxic freshwaters that lacks mitochondria. Monoprotist cultures of this species contained naked trophic cells with anterior flagellar insertion and a conspicuous ventral groove. Bacteria were ingested at the posterior end of the ventral groove, but there was no persistent cytopharyngeal complex. The posterior flagellum resided in this groove, and bore two prominent vanes. A Golgi body (dictyosome) was present adjacent to the flagellar insertion. The kinetid consisted of four basal bodies, four microtubular roots, and associated fibers and bands. Duplicated kinetids, each with four basal bodies and microtubular root templates, appeared at the poles of the open mitotic spindle. Trimastix pyriformis is distinguishable from other Trimastix species on the basis of external morphology, kinetid architecture and the distribution of endomembranes. Trimastix species are most similar to jakobid flagellates, especially Malawimonas jakobiformis, and to species of the retortamonad genus Chilomastix. Retortamonads may have evolved from a Trimastix-like ancestor through loss of "canonical" (easily seen with electron microscopy) endomembrane systems and elaboration of cytoskeletal elements associated with the cytostome/cytopharynx complex.     

Ultrastructure of oesophageal appendages ("peptonephridia") in enchytraeids (Annelida: Clitellata)

Abstract. Although the oesophageal appendages in the four enchytraeids Enchytrueus crypticus, Fredericia strinta, Buchholzia appendiculata , and Achaeta sp. are quite different from one another in shape and position, their histology and ultrastructure are basically the same. These are intestinal appendages, the lumina of which distally end blind and proximally open into the oesophagus. Almost all of the few cells in their single-layered epithelium have a microvillous, cilia-free border at the apex, facing towards the lumen, and basally comprise an extremely extensive labyrinth. The presence of the latter, composed of very thin cell processes, and of numerous mitochondria identifies the organs as energy-producing and -consuming, transport-active structures. Their possible function as a food-moistening organ or osmoregulatory organ is discussed, and they are compared with other intestinal appendages in enchytraeids and other oligochaetes.     

Observations on the mature gametophyte of Phylloglossum (Lycopodiaceae)

Mature, gametangia-bearing photosynthetic gametophytes of Phylloglossum can be grown from the nonphotosynthetic, cylindrical, negatively gravitropic immature stages in illuminated axenic culture on a nutrient medium with or without 0.2% glucose. The gametangial-bearing region of these gametophytes, the photosynthetic crown, grows horizontally from the apex of the immature cylindrical stage. At maturity the photosynthetic crown is thickened and bilaterally symmetrical. It is usually narrow and bean-shaped with dorsal and ventral regions. Occasionally, the ventral region becomes thicker and the crown is deltoid in cross section. The dorsal edge or ridge of the crown is the gametangial region with archegonia and antheridia. The gametangia are often hidden because they are interspersed among numerous uni- or bicellular paraphyses. The lateral surfaces below the gametangial region lack outgrowths, and the ventral region is covered with long rhizoids. The apical meristem at the anterior end of the crown is overarched by the developing dorsal tissue of the gametangial ridge. The lower derivatives of the meristem form the ventral region with rhizoids. Phylloglossum gametophytes are unusual because their mode of organic nutrition changes from mycorrhizal to photosynthetic during ontogeny.     

Epiphytism and terrestrialization in tropicalHuperzia (Lycopodiaceae)

A gap in the exospore and the presence of a mesospore is found to be a normal part of development in the ten species ofSelaginella we have studied. The early spore wall consists of an exospore and a mesospore forming successively on the plasma membrane of the megaspore protoplast when it is 10–15 µm in diameter. Enlargement of the exospore and mesospore creates a central space, the lumen of the megaspore, around the megaspore protoplast. After that there is a vast enlargement of the exospore and a relatively small enlargement of the mesospore. The exospore splits close to its contact with the mesospore forming a gap over equatorial and distal regions. The gap becomes greatly expanded and becomes filled with lipids, PAS-positive carbohydrates, proteins and is crossed by wicks. Experiments with solutions of different osmolality on fresh megaspores show that the exospore and mesospore are not osmotic barriers. The mesospore appears not to be resistant to acetolysis at the many stages tested but exospore is resistant. Thus the mesospore size and shape is retained by the inner exospore that enveloped the mesospore. At maturation the mesospore undergoes lysis and absorption. At the beginning of germination stages an endospore forms at the inner part of the exospore. This inner part of the exospore, that adhered to and enveloped the mesospore, becomes pressed near to the bulk of the exospore. Until pregermination stages the megaspore protoplast is small (10–20 µm in diameter).     

Amino acid sequence study of ferredoxin from a club moss,Lycopodium clavatum L

A ferredoxin was purified as the pure state from a club moss (Lycopodium clavatum L.) and sequenced. The ferredoxin was composed of 99 amino acids and had a molecular mass of 10,728, excluding iron and sulfur atoms. The ferredoxin sequence was rather distinct from that fromMarchantia polymorpha, Equisetum andGleichenia japonica. Based on comparison of ferredoxin sequences thus far established, the phylogenetic relationship between lower vascular plants is discussed.