Surface ultrastructure of the uredinial stage ofCerotelium fici and its infection process on mulberry

Surface morphology of uredinia and urediniospores ofCerotelium fici (Cast.) Arth., and its infection process in mulberry (Morus alba L.) have been described using the scanning electron microscope. The uredinia ofC. fici are paraphysate and bear pedicellate urediniospores. The surface morphology of urediniospore is similar to most of the rust fungi which have pedicellate urediniospores. The infection process ofC. fici on mulberry leaves differs from other rust fungi in not forming appressoria over the stomates. Further, the germ tube of the urediniospore crosses over the stomata, and sometimes forms an appressorium close to the stoma rather than forming over it. Thus, the present study indicates that the formation of appressoria byC. fici on mulberry leaves is not site specific but an independent, specialized and inherent mechanism required byC. fici to penetrate the mulberry leaf cuticle and epidermis.     

Comparative ultrastructure of aecial and telial infections of the autoecious rust fungus Puccinia tuyutensis

This study demonstrates morphological differences between aecial and telial stages of the autoecious rust Puccinia tuyutensis. The aeciospores possess verrucose ornamentation while the teliospores have smooth surfaces. The aecial and telial haustoria of this rust produced in the mesophyll of Cressa cretica differ morphologically in the following respects:(1) the haustorial mother cell of telial haustorium is more differentiated than that of aecial haustorium and its wall at the penetration site is composed of 4 layers; (2) the aecial haustorium is filamentous in appearance and slightly constricted at the point of entry into the host cell, while the telial haustorium is clavate and possesses a narrow neck with a densely staining neckband and swollen body; (3) the neck of the telial haustorium is always associated with numerous vesicles while that of the aecial haustorium is not. Vascular tissue of host leaves is heavily invaded by aecial haustoria but not by telial haustoria.     

Taxonomy ofPuccinia species causing rust diseases on sugarcane

A taxonomic revision ofPuccinia species causing rust diseases on sugarcane was conducted to clarify their morphological characteristics. Specimens including previously reported species,Puccinia melanocephala, P. kuehnii andPuccinia sp.sensu Muta, 1987, were collected in Japan and the Philippines and borrowed from various herbaria worldwide. Morphological characteristics of these specimens were examined under light and scanning electron microscopes. Comparative morphological studies of the specimens showed that rust fungi infecting sugarcane could be classified into two species,Puccinia melanocephala andP. kuehnii. Puccinia sp.sensu Muta was morphologically identical withP. kuehnii. Results of this study corroborate previous phylogenetic analysis results of D1/D2 regions of LSU rDNA gene. Contribution No. 157, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba     

Mating type of isolates derived from the spermogonial state ofPuccinia coronata var.coronata

Hyphal confrontation between two haploid cultures originating from single basidiospores was used to determine the mating type ofPuccinia coronata var.coronata. Pairs of 15 single-basidiospore cultures were placed approximately 1 mm apart on the medium in all possible combinations. Hyphae of the pairs of colonies came into contact with each other in all combinations approximately two weeks after confrontations. When the nuclear number of hyphal cells in a contact zone was investigated one month after confrontation, monokaryotic hyphae were observed in selfing combination. On the other hand, dikaryotic hyphae were observed in 90.5% of crossing combinations between different cultures. Two isolates are considered compatible if dikaryotic hyphae are present in the contact zone but incompatible if they are absent. The mating type of the fungus was found to be characterized by multiple-allelomorphic tetrapolar incompatibility controlled by the “A” and “B” incompatible factors. Contribution No. 116, Laboratories of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba     

Development ofPuccinia striiformis West. on nutrient agar

Uredospores of a barley isolate ofPuccinia striiformis West. were germinated on glucose peptone agar and the development of colonies was observed with a microscope. A small number (0.1–1%) of germ tubes did not abort during the first 20 h of incubation and either differentiated an infection structure or continued slowly to elongate for several days. In 4 out of 9 experiments some of these sporelings produced colonies that reached maximum size (0.15–0.20 mm) after 3 weeks at 15° C.     

Aecidium dispori is the aecial anamorph ofPuccinia albispora, sp. nov. (Uredinales)

Aecidium dispori forms spermogonium and aecium onDisporum sessile andD. smilacinum, which are distributed in East Asia. TheAecidium species is found to be an aecial anamorph of aPuccinia fungus, with its uredinial-telial stage being formed onCarex conica, C. dolichostachya subsp.multifolia, C. pisiformis subsp.alterniflora andC. rugata. Urediniospores of this fungus are large, colorless, thick-walled with 4–5 equatorial germ pores. The morphological characteristics of urediniospores and the spermogonial-aecial host do not fit to any set of circumscribing characters of previously described species. We consider the fungus to be a new species and propose a new name,Puccinia albispora, for the fungus.     

Observations on the ultrastructure of the copulatory organ of Archilopsis unipunctata (Fabricius, 1826) (Proseriata,Monocelididae)

The copulatory organ in adult specimens of Archilopsis unipunctata has been studied by transmission electron microscopy.This copulatory organ is of the conjuncta-duplex type with eversible cirrus. The seminal vesicle, lined with a nucleate epithelium, is surrounded by spirally arranged muscles. The fibres are enclosed in a sheath that is continuous with the septum of the bulbus and the basement lamina of the male canal epithelium. Distally to the seminal vesicle the bulbus is filled with the secretory cell-necks of the prostate glands. The male canal shows three different parts: seminal duct, ejaculatory duct and eversible cirrus. At the transition of seminal duct and ejaculatory duct two prostate ducts open into the lumen. The structure of the epithelium lining the different parts of the canal is described. The transition into the cirrus may be recognized by an abrupt change in the thickness, the electron density and the stratification in the basement lamina and by the disappearance of the epithelium absent indeed in the cirrus. The material found inside the cirrus-lumen is different according to the zone considered. The origin of this material and of the cirrus teeth is discussed.Abbreviations ab- apoptotic body - ba- bacteria - bb- basal bodies of cilia - bl- basement lamina - bw- body wall - c- cilia - cb- cell body - cgp- common genital porus - ci- cirrus - cip- cirrus plug - cl- lumen of cirrus - cm- circular muscles - cr- cytoplasmatic remnants - cs- cytoplasmatic sheets - ejd- ejaculatory duct - ep_ej- epithelium of ejaculatory duct - d- desmosomes - f- flagella of spermatozoa - fd- female duct - fp- female porus - gc- golgi complex - gl- glycogen particles - hd- hemidesmosomes - lm- longitudinal muscles - ly- lysosome-like body - m- muscles - m_b- muscles of the bulbus - m_c- muscles of the cirrus - m_c- muscles of the seminal vesicle - mi- mitochondria - ml- microvilli - ms- mesenchyme - n_sd- nuclei of the seminal duct - pd- prostate duct - pg- prostate glands - ri- ribosomes - s- septum - sb- secretory vesicle - sd- seminal duct - sp- spines - sv- seminal vesicle - v- vagina - vd- vas deferens     

Observations on the ultrastructure ofFrankia sp. in root nodules ofDatisca cannabina L.

Summary The fine structures of the microsymbiont inside the root nodules ofDatisca cannabina have been studied by light, by transmission- and by scanning-electron microscopy. The endophyte is prokaryotic and actinomycetal in nature. The hyphae are septate and branched, diameter 0.3–0.5 m. The tips of hyphae are swollen to form electron-dense, clubshaped to filamentous vesicles, ranging in diameter: 0.4–1.4 m. The endophyte penetrates through walls of the cortial cells. The infected zone is kidney shaped and confined to one side of the acentric stele. The orientation of infection is reversed from other actinorhizae exceptCoriaria. The hyphae are near the host cell wall and vesicles are directed towards the central vacuole. Vesicles are aseptate and no collapsing of the vesicle cell wall (void area) has been observed. Vesicle clusters structures are globular with an opening at one side of the cluster. The host cell is multinucleate or contains a lobed nucleus. Groups of mitochondria are located in between the hyphae, suggesting a strong association between the host and the endophyte for energy supply and amino acid production. The consequences of the inability to separate the mitochondria from the vesicle clusters in nodule homogenates in physiological studies have been discussed.Isolated vesicles clusters showed dehydrogenase activity, indicated by the presence of formazan crystals, after incubation with NADH and NBT. Strongest reducing activity was found within the vesicles. The possible role of filamentous vesicles in nitrogen fixation has been discussed.     

The ultrastructure of anthocyanoplasts in red-cabbage

A study of the ultrastructure of anthocyanoplasts from the seedling hypocotyl and leaves from the heart of red-cabbage plants has been made. Evidence is presented that the anthocyanoplast does not represent a hydrophobic droplet but is bounded by a single tripartite membrane approximately 10 nm in thickness. The results provide further support for the view that the anthocyanoplast is an intracellular compartment containing at least the later enzymes of anthocyanin biosynthesis, which are thereby separated from the hostile acidic environment of the vacuolar sap.     

阔鳞瘤蕨(水龙骨科)卵细胞发育超微结构观察

水龙骨科是蕨类植物中最进化的类群,该文采用超微技术对水龙骨科的阔鳞瘤蕨(Phymatosorus hainanensis)卵发育过程进行观察,以完善薄囊蕨植物卵发生的资料,为揭示蕨类植物的有性生殖及演化机制奠定基础。结果表明:(1)幼卵、颈沟细胞、腹沟细胞通过胞间连丝紧密连接。(2)发育过程中,卵与腹沟细胞之间细胞壁显著加厚,将卵细胞与腹沟细胞隔离。(3)在壁的下方产生分离腔,内含大量不定形物质,但卵细胞与腹沟细胞在中间处始终相连。(4)分离腔中的不定形物质沉积在卵细胞质膜外形成了一层加厚的卵膜,而在连接区(孔区)处不形成卵膜,该位置最终形成了受精孔。(5)卵细胞核变得高度不规则,近成熟时卵核产生了大量的核外突。     

Variability in size and ultrastructure of the statospore of Mallomonas caudata

Using light and scanning electron microscopy the statospore of Mallomonas caudata was described from phytoplankton collected from 9 lakes situated in Southern Sweden. The cysts differed in size to the same degree irrespective of the lake. However, the ultrastructure of the cysts varied both within the population of a lake and between lakes. The implications of this variability for paleoecological studies are briefly discussed.     

The ultrastructure of cerebral blood capillaries in the raffish,Chimaera monstrosa

Summary Sharks and skates (Chondrichthyes: Elasmobranchii) have a glial blood-brain barrier, while all other vertebrates examined so far have an endothelial barrier. For comparative reasons it is desirable to examine the blood-brain barrier in species from the other subclass of cartilaginous fish, the holocephalans. The ultrastructure of cerebral capillaries in the chimaera (Chondrichthyes: Holocephali) is described in the present study. The endothelial cells are remarkably thick. Fenestrae and transendothelial channels were not observed. The endothelial cells are joined by elaborate tight junctions. The perivascular glial processes are separated by wide spaces (15–60nm) without obliterating junctional complexes. These findings indicate that the chimaera has an endothelial blood-brain barrier.     

The ultrastructure of the spermatozoon of Lernaeocera branchialis (Copepoda : Pennellidae)

Spermatozoa are produced by males of the fish-parasitic copepod, Lernaeocera branchialis, on the flounder (Platichthys flesus) host and packaged into spermatophores. Mature spermatozoa from spermatophores have been investigated with light microscopy and t.e.m. and s.e.m. techniques. Each is a filiform cell up to 30 µm long and 1 µm in diameter, being symmetrically tapered at each end to produce a javelin-shaped configuration. Surface s.e.m. appearances suggest that the cell is helically twisted. The spermatozoon possesses no flagellum, no nuclear envelope, no mitochondria and no orthodox acrosome. For most of its length the cell has a four-lobed appearance in transverse section and contains little more than a cylindrical sleeve of pseudomembranous material with which is associated finely filamentous or granular material which is assumed to be nuclear chromatin. The spermatozoon is immobile in seawater.The ultrastructure of L. branchialis spermatozoa has been compared with that of eight other copepod species.     

Cytochemical localization and ultrastructure of Aspergillus flavus in cottonseed

Cottonseeds having fluorescent fibers were harvested from fields in Arizona and examined utilizing light microscopy and transmission electron microscopy. The occurrence of fluorescent fibers indicated that seeds had been infected by Aspergillus flavus during development. Presence of A. flavus was verified by plating portions of seeds with fluorescent fibers. Hyphae, conidial heads, and conidia were identified readily in differentially-stained cotyledon tissue processed for light microscopy. Utilization of transmission electron microscopy permitted observations on lignified seed coats and cotyledons of mature cottonseeds. Hyphae were located throughout the cotyledon and in the nonlignified layers of the seed coat. The identification of hyphae in cross sections of vessel elements within the seed coat provided ultrastructural evidence supporting the hypothesis that A. flavus may enter seeds via the vascular tissue. Controls for the microscopy studies included observations on cottonseeds with no visual signs of infection and on laboratory-grown cultures of A. flavus. These observations demonstrated that the hyphae localized within fluorescent seeds had features characteristic of A. flavus and that fungal-like structures do not occur within uninfected seeds.     

Cortical ultrastructure of freeze-substituted protonemata of the mossFunaria hygrometrica

Summary The ultrastructural organization of the cortical cytoplasm has been examined in caulonemata, branches and buds of the mossFunaria hygrometrica, which were prepared by rapid freeze-fixation and freeze-substitution (FS). The same structural components occur in the cortex of all three cell types: microtubules (MTs), endoplasmic reticulum (ER), coated and uncoated vesicles, coated pits, and dictyosomes. However, the configuration and density of the cortical ER varies between the three. Caulonemata have an open, polygonal network of ER associated with long MTs oriented mostly parallel to the length of the cell. Lamellar ER, covered with polysomes, is interspersed in the network. Branches have a more tightly arranged ER network, at places occurring in a thick layer, and occasional polysome-decorated lamellae. MTs, which extend to the tip of the branch, are oriented mainly parallel to the cell's long axis and are associated with the cortical ER. Buds have the tightest ER network, which is frequently arranged in a thick layer. Tubules in the polygonal ER of buds are densely covered with ribosomes, whereas tubules in the ER network of caulonemata and branches range from nearly smooth to moderately rough. Closely-spaced ER lamellae, with many polysomes, occur in some buds. The MTs of buds extend into the apical dome and are associated with the cortical ER, but are more randomly oriented than in caulonemata or branches. Close appositions between the ER and PM are observed in all three cells, but are more frequent in buds.Abbreviations DiOC₆(3) 3,3-dihexyloxacarbocyanine iodide - ER endoplasmic reticulum - FS freeze-substitution - MT microtubule - MF microfilament - PM plasma membrane     

Ribosomal DNA-ITS sequence polymorphism in the sugarcane rust,Puccinia kuehnii

The two highly divergent ITS types previously observed in isolates ofPuccinia kuehnii were amplified from the same isolates through the use of ITS type-specific primers for PCR and are therefore considered as polymorphisms of ITS regions within the species. Although homology of sequences of one of the ITS types with otherPuccinia species was of expected levels, significantly high homology of sequences of the other type with those ofCronartium members indicates that abnormal genetic events led to the occurrence of these polymorphic regions. These results indicate that ITS gene tree phylogeny may not reflect true species phylogeny in this group of rust fungi. Rather, D1/D2 region tree phylogeny, which was concordant with the differences in morphology with and among related rusts, more correctly reflects phylogenetic relationships of sugarcane and related grass rusts. contribution No. 159, Laboratory of Plant Parasitic Mycology, Institute of Agriculture and Forestry, University of Tsukuba.     

Quantitative estimation of the surface carbohydrates on the infection structures of rust fungi with enzymes and lectins

Lectins of Triticum vulgaris (WGA), Concanavalia ensiformis (ConA), Phaseolus vulgaris (PHA), Lotus tetragonolobus (LTA), Arachis hypogaea (PNA), Ricinus communis (RCA I), Griffonia simplicifolia (GSA II) and the enzymes endo-(13)--D-glucanase, exo-(13)--D-glucanase and laminarinase were tested for binding to the infection structures of Puccinia coronata and Uromyces appendiculatus. The enzymes and lectins were labeled with fluorescein and the fluorescence was measured with a microscope photometer. GSA II and ConA bound to all parts of the two rust fungi to a certain extent. The germ tubes of P. coronata bound at least two times more WGA than did the germ tubes of U. appendiculatus. The appressoria of both rust fungi additionally bound exo-(13)--glucanase, endo-(13)--glucanase and laminarinase. The substomatal vesicle and the infection hypha of both rust fungi mainly bound the glucanases. Furthermore, the substomatal vesicle of U. appendiculatus bound PHA. No obvious binding with LTA, RCA I and PNA was observed. Binding generally could be inhibited by appropriate haptens. Binding to uredospores generally appeared unspecific. The results indicate that the germ tubes have chitin on their outer surfaces, the appressoria chitin and glucans and the substomatal vesicles and infection hyphae mainly glucans. Compared to P. coronata, U. appendiculatus has more terminal linked glucose residues or the glucan has more (13)--linkages. Also, U. appendiculatus has N-acetylgalactosamine or a similar sugar on the surface of the substomatal vesicle.Abbreviations ConA Concanavalia ensiformis agglutinin - FITC fluorescein isothiocyanate - GSA II Griffonia simplicifolic agglutimin II - LTA Lotus tetragonolobus agglutinin - PBS phosphate buffered saline - PNA Peanut agglutinin - RCA I Ricinus communis agglutinin I - PHA Phaseolus vulgaris agglutinin - WGA Wheat germ agglutinin     

华东安蕨卵发生的超微结构观察

核心薄囊蕨是蕨类植物中的进化类群,但对受精作用具有显著影响的卵发生研究仍较少,该文利用超微技术对其中蹄盖蕨科的华东安蕨卵发生过程进行了研究,以进一步完善薄囊蕨植物卵发生的科学资料,为理解蕨类植物的有性生殖及演化机制奠定基础。超微结构观察显示:华东安蕨的幼卵和沟细胞在颈卵器中紧密联接;随后,在卵细胞上方出现了分离腔和临时细胞壁,但在卵细胞中间孔区处卵细胞和腹沟细胞始终联接在一起;分离腔中的无定形物质沉积在卵细胞的质膜外形成了1层加厚的卵膜,而在孔区处没有形成卵膜,该位置最后形成了受精孔。在进一步的卵发生过程中,卵细胞核变得高度不规则,形成了大量的核外突和核褶皱。     

The ultrastructure of micropropagated and greenhouse rose plant stomata

Stomata of leaves from in vitro grown rose plantlets remain opened in the dark. The ultrastructure of their guard cells was studied after a 7 h light and a 7 h dark period, and compared to that of functional stomata from plants which have been acclimatized to greenhouse conditions. Qualitative and quantitative observations concerning the shape of the guard cells, mitochondria, plastids and starch grains, demonstrated the similarity in guard cell ultrastructure. The peculiarity of guard cell ultrastructure of in vitro cultured plants was the inability to close in the dark; vacuolar area was 40% of the whole guard cell area during both light and dark period whereas, in guard cells from greenhouse plants, the vacuolar area was 40% of the whole guard cell area during the light and only 25% during the dark period. These results indicate that stomata from in vitro plants are duly developed and possess an ultrastructure suitable for a typical functioning. The inability to close in the dark results from atypical water relation.     

Surface ultrastructure of the adult stage of Acanthotrema felis (Trematoda: Heterophyidae)

The surface ultrastructure of Acanthotrema felis (Trematoda: Heterophyidae) adults, recovered from a kitten experimentally infected with the metacercariae, was observed using a scanning electron microscope. The worm was leaf-like, ventrally concave and covered with scale-like multi-pointed tegumental spines. The spines on the anterior surface were short but broad, and had 10-12 pointed tips. The cytoplasmic processes protruded around the spines, like pockets for the spines. The ventrogenital opening was crescent, or kidney-shaped, and had protuberances with minute spines on its surrounding tegument. The spines on the posterior surface were long, but narrow, with 6-8 pointed tips. The cytoplasmic processes on this tegument were ridge-like, and elevated along the row of the spines. The surface ultrastructure of A. felis is generally similar to that of other heterophyid flukes, but some features are characteristic, and may be of taxonomic and bio-ecological significance.