Light and electron microscopical observations on the heterotrophic protist Thaumatomastix salina comb. nov. (syn. Chrysosphaerella salina) and its allies

The marine flagellates presently known as the chrysophytes Chrysosphaerella salina and C. tripus Takahashi & Hara have been refound and studied with light microscopy and whole mounts for electron microscopy. Based on material from Australia and Denmark (the latter from the type locality), C. salina is shown to be a colourless protist related to Reckertia sagittifera Conrad. It is characterized by a combination of flagellar features previously thought to be restricted to Reckertia , i.e. a short anterior flagellum which is scale-clad, and a longer, usually posterior but naked flagellum. The scales on the body are shown to be silicified. The new light microscopical studies have also shown considerable resemblance between C. salina, C. tripus and the genus Thaumatomastix Lauterborn. C. salina and C. tripus are therefore transferred to this genus together with Reckertia and the 2 marine species described since 1980 as belonging to Chrysosphaerella, C. triangulata Balonov and C. patelliformis Takahashi & Hara. Thaumatomastix bipartita sp.nov. is illustrated and described.
Chrysosphaerella appears to be a genus of photosynthetic, colony-forming chrysophytes restricted to freshwater habitats. Thaumatomastix is a genus of heterotrophic protists, usually solitary, which occurs in both marine and freshwater environments. The two genera show little, if any, phylogenetic relationship to each other.     

Presence of the dinoflagellates Ceratium dens, C. fusus and C. furca (Gonyaulacales: Ceratiaceae) in Golfo de Nicoya, Costa Rica

Harmful Algae Blooms (HAB) are a frequent phenomenon in the Gulf of Nicoya, Costa Rica, as in other parts of the world. The morphology and physiology of these microalgae are important because HAB species have adaptive characteristics. The production of high concentrations of paralytic toxins by Ceratium dinoflagellates has only been documented at the experimental level. However, this genus has been associated with the mortality of aquatic organisms, including oyster and shrimp larva, and fish, and with decreased water quality. Recently, fishermen reported massive mortality of encaged fish near Tortuga Island (Gulf of Nicoya). Samples were taken from an algal bloom that had produced an orange coloration and had a strong foul-smelling odor. Ultrastructural details were examined with scanning electron microscopy. The dinoflagellates Ceratium dens, C. furca and C. fusus were found in samples taken at the surface. The cell count revealed four million cells of this genus per liter. The morphological variability of these species is high; therefore electron microscopy is an useful tool in the ultrastructural study of these organisms. This is the first time that three Ceratium species are reported concurrently producing harmful blooms in Costa Rica.     

Isolation and morphological characterization of a mycelial mutant of Candida albicans.

In this paper we describe the isolation of a novel strain of Candida albicans which is a mycelium at ambient temperatures. Mutagenesis of C. albicans ATCC 10261 with N-methyl-N-nitro-N-nitrosoguanidine followed by plating on solid media at 28 degrees C yielded colony morphology variants which were characterized by a raised, rough-surfaced colony of irregular outline in marked contrast to the flat, shiny circular colonies of the parental 10261 strain. One mutant colony, hOG301, was studied in detail. Strain hOG301 was stable and exhibited mycelial morphology over a wide temperature range (5 to 40 degrees C) in several media. The hyphae comprising hOG301 mycelium were examined by light microscopy, scanning electron microscopy, and transmission electron microscopy and showed morphological features described in the literature as being typical of both true hyphae and pseudohyphae. In contrast to 10261, hOG301 was not pathogenic after intraperitoneal injection in mice. This is the first report of a mycelial C. albicans that is stable at ambient temperatures.     

Pollen morphology of the genus Cornukaempferia (Zingiberaceae) in Thailand

Cornukaempferia is a recently described genus of Zingiberaceae which only occurs in Thailand as a rare genus with limited geographical distribution. Only three species have been described so far, including a recently described new species, C. larsenii. These three species are morphologically very similar and additional data on other biological aspects are useful for the elucidation of their relationship. Pollen morphology of all three species of genus Cornukaempferia has been studied by light microscopy and scanning electron microscopy. The pollen grains are monad, spherical, inaperturate. The exine sculpture is echinate with psilate between the spines for C. aurantiflora and C. longipetiolata, or echinate with regulate between the spines for C. larsenii. This obser-vation helps support the taxonomic status of C. larsenii.     

Morphological discretion of basidiospores of the puffball mushroom Calostoma by electron and atomic force microscopy

Comparative morphology among species of the genus Calostoma, including C. cinnabarina, C. ravenelii, and C. japonicum, was investigated by scanning electron microscopy and atomic force microscopy. Spore morphology of cinnabarina and C. ravenelii showed no dramatic differences by light microcopy and scanning electron microscopy. To differentiate these species, atomic force microscopy was employed. Quantitative analysis of the surface roughness basidiospores revealed subtle differences in height fluctuation at the nanometer scale between the species of Calostoma. Basidiospores of C. cinnabarina had a relatively rougher surface than those of C. ravenelii at 2.0 x 2.0 micro m2 scan areas.     

NMR and CD studies on an oligonucleotide containing N4-methylcytosine.

The hexamer d(CGm4CGCG) exists predominantly as a right handed B form helix at 20 degrees C in 150 mM NaCl, as shown by 2D NOE spectra. Under these conditions a minor species is also observed which corresponds to the single strand in slow exchange on a proton NMR time scale with the double strand. This exchange is unusually slow and separate resonances for the two species are seen up to 65 degrees C. At 50 degrees C the lifetime of the single strand species is 0.85 s. Under high salt conditions the hexamer is partly converted into the Z form, but the complete transition is only observed at 5M NaCl at -6 degrees C.     

Temperature-regulated formation of mycelial mat-like biofilms by Legionella pneumophila

Fifty strains representing 38 species of the genus Legionella were examined for biofilm formation on glass, polystyrene, and polypropylene surfaces in static cultures at 25 degrees C, 37 degrees C, and 42 degrees C. Strains of Legionella pneumophila, the most common causative agent of Legionnaires' disease, were found to have the highest ability to form biofilms among the test strains. The quantity, rate of formation, and adherence stability of L. pneumophila biofilms showed considerable dependence on both temperature and surface material. Glass and polystyrene surfaces gave between two- to sevenfold-higher yields of biofilms at 37 degrees C or 42 degrees C than at 25 degrees C; conversely, polypropylene surface had between 2 to 16 times higher yields at 25 degrees C than at 37 degrees C or 42 degrees C. On glass surfaces, the biofilms were formed faster but attached less stably at 37 degrees C or 42 degrees C than at 25 degrees C. Both scanning electron microscopy and confocal laser scanning microscopy revealed that biofilms formed at 37 degrees C or 42 degrees C were mycelial mat like and were composed of filamentous cells, while at 25 degrees C, cells were rod shaped. Planktonic cells outside of biofilms or in shaken liquid cultures were rod shaped. Notably, the filamentous cells were found to be multinucleate and lacking septa, but a recA null mutant of L. pneumophila was unaffected in its temperature-regulated filamentation within biofilms. Our data also showed that filamentous cells were able to rapidly give rise to a large number of short rods in a fresh liquid culture at 37 degrees C. The possibility of this biofilm to represent a novel strategy by L. pneumophila to compete for proliferation among the environmental microbiota is discussed.     

14种剑蕨属植物的孢子形态特征及其系统分类学意义

利用扫描电子显微镜对水龙骨科(Polypodiaceae)剑蕨属(Loxogramme)14种植物的孢子形态和表面纹饰进行了观察。结果显示:剑蕨属的孢子具有单裂缝和三裂缝两种类型,个别物种具有中间过渡类型。剑蕨属的孢子纹饰为蠕虫状或浅波纹状。经比较发现,具三裂缝孢子的物种通常植株较小,而具单裂缝的种类则通常植株较大。从进化的角度来看,三裂缝孢子为原始类型,单裂缝孢子为进化类型,因而从孢子形态特征的角度支持剑蕨属为水龙骨科基部类群。     

Morphological studies on the nutlet of Turkish Cyclotrichium Manden. & Scheng. (Lamiaceae)

Morphological characters of the nutlets of Cyclotrichium Manden. & Scheng. in Turkey were examined using scanning electron microscopy (SEM). The genus Cyclotrichium is represented by six species in Turkey, of which two are endemic for Turkey. Nutlet morphology of the species was studied using stereoscopic microscopy and SEM, and the features were described and illustrated. Nutlet morphology of the examined specimens exhibits some variation in size, shape and sculpture. Nutlets range from 1.1 to 2.0 mm in length and 0.5 to 1.0 mm in width and are elliptic, oblong to ovoid and trigonous in shape. Nutlet sculpture can be divided into two main types: distinctly or weakly reticulate pattern in C. niveum, C. origanifolium, C. longiflorum and rounded cell arrangement in the remaining species. Micromorphological characters could be useful in solving taxonomic problems of Cyclotrichium.     

Comparative morphology and molecular phylogeny of Apicoporus n. Gen.: a new genus of marine benthic dinoflagellates formerly classified within Amphidinium

The composition of the dinoflagellate genus Amphidinium is currently polyphyletic and includes several species in need of re-evaluation using modern morphological and phylogenetic methods. We investigated a broad range of uncultured morphotypes extracted from marine sediments in the Eastern Pacific Ocean that were similar in morphology to Amphidinium glabrum Hoppenrath and Okolodkov. To determine the number of distinct species associated with this phenotypic diversity, we collected LM, SEM, TEM and small subunit ribosomal DNA sequence information from different morphotypes, including the previously described A. glabrum. Both comparative morphological and molecular phylogenetic data supported the establishment of a new genus, Apicoporus n. gen., including at least two species, A. glaber n. comb., and A. parvidiaboli n. sp. Apicoporus is characterized by having amphiesmal pores and an apical pore covered by a hook-like protrusion; neither of these characters has been observed in other athecate dinoflagellates. The posterior end of Apicoporus parvidiaboli possessed varying degrees of "horn formation", ranging from slight to prominent. By contrast, the posterior end of Apicoporus glaber was distinctively rounded and lacked evidence of horn formation. Although these species were previously interpreted to be obligate heterotrophs, TEM and epifluorescence microscopy demonstrated that some cells of both species had unusually small but otherwise typical dinoflagellate plastids. The number and density of plastids in any particular cell varied significantly in the genus, but the plastids were almost always concentrated at the posterior end of the cells or around the nucleus. The presence of cryptic photosynthetic plastids in these benthic species suggests that photosynthesis might be much more widespread in dinoflagellates than is currently assumed.     

国产省藤属植物的花粉形态学

对国产棕榈科省藤属(Calamius L.)15种植物的花粉进行了光学和扫描电镜观察,其中12种为首次报道。省藤属的花粉均为两沟型花粉,外壁覆盖层多为网状纹饰(大喙省藤C．macrorrhynchus)或具穿孔(华南省藤C.rhabdocladus)。首次发现省藤属花粉的外壁纹饰存在穿孔和外壁疣状突起的类型(阔叶鸡藤C.pulchellus)以及皱波状突起的类型(长鞭省藤C.flagellum)。花粉的大小、形状、外壁纹饰、外壁是否有突起,外壁厚度和网状纹饰网眼的大小,对于省藤属的种级分类有较大的意义。     

Pollenmorphologie Von Borago Officinalis L.

The pollen morphology of the 16 recognized species of the genus Asphodelus L. (Asphodelaceae) has been investigated by light and scanning electron microscopy. Four pollen types can be distinguished on the basis of variation in size of the polar, equatorial longitudinal and transverse axes, as well as in exine structure and sculpturing, which correlate with the subdivision of the genus into sections. Correlations between pollen size and some biological characters are made. Phylogenetic implications are suggested, and trends of pollen evolution in the genus are indicated.     

Systematics of the Genus Eubothrium Nybelin (Cestoda, Pseudophyllidea), with Partial Re-description of the Species

Material from as many species of the cestode genus Eubothrium as could be obtained (six out of nine existing species), from a range of hosts and from both marine and freshwater habitats, were examined both by light and scanning electron microscopy. The scolex shape as seen with SEM turned out to be a very valuable specific character. Particular attention was also paid to the possibility that intra-specific races, distinguishable on biological criteria, might in addition exhibit characteristic morphological differences.     

Immobilization of anaerobic bacteria on rubberized-coir for psychrophilic digestion of night soil

Low-ambient temperatures, <30 degrees C, are known to cause drastic reduction in the efficiency of anaerobic biodigesters due to low-growth rate of the constituent bacterial consortium. Immobilization of anaerobic bacteria has been attempted in the biodigester operating at 10 degrees C. Various matrices were screened and evaluated for the immobilization of bacteria in digesters. Anaerobic digestion of night soil was carried out with hydraulic retention time in the range of 9-18 days. Among the tested matrices, rubberized-coir was found to be the most useful at 10 degrees C with optimum hydraulic retention time of 15 days. Optimum amount of coir was found as 25 g/L of the working volume of biodigesters. Immobilization of bacteria on the coir was observed by scanning electron microscopy and fluorescent microscopy. The study indicates that rubberized-coir can be utilized to increase biodegradation of night soil at higher organic loading. Another advantage of using this matrix is that it is renewable and easily available in comparison to other synthetic polymeric matrices.     

Pleomorphism of fusobacteria isolated from the cockroach hindgut.

Fusobacteria are commonly isolated from the hindgut of the cockroach Eublaberus posticus . Eleven strains isolated from E. posticus by us were keyed to four species, Fusobacterium necrophorum, F. varium , F. gonidiaformans , and F. prausnitzii , using current taxonomic criteria. With the exception of F. gonidiaformis , all species showed rods with swollen centers and large bodies. The pleomorphism of F. varium was examined by phase microscopy and scanning and transmission electron microscopy. The pleomorphic process begins with a gradual swelling at the center of the rod until a large round body is formed. Some of these round bodies then fragment, giving rise to rod-shaped cells. When 10% yeast extract was added to growth media, pleomorphism was not induced. A dialyzable factor was found to account for this observation. Fermentation of [1-14C]glutamic acid gives rise to butyrate labeled in the carboxyl carbon, indicating that butyrate is formed by the hydroxyglutarate pathway which may be characteristic for the genus Fusobacterium.     

Fertilizing capacity and ultrastructure of fowl and turkey spermatozoa before and after freezing.

The fertilizing capacity, motility and ultrastructure of fowl and turkey spermatozoa were examined at various stages of the freezing process. For both species, fertility and motility were depressed after equilibration with dimethyl-sulphoxide at 5 degrees C. After freezing, motility was maintained at 55% for fowl spermatozoa and 40% for turkey spermatozoa; however, fertility was 55% for the fowl and 0% for the turkey. Qualitatively, the damage to the spermatozoa of both species was nearly identical, as revealed by scanning and transmission electron microscopy. The plasmalemma was the primary site of damage. 'Bent' spermatozoa, coiled tails and swollen mitochondria were also present. Damage to the acrosome was only observed in spermatozoa which had been frozen to -180 degrees or -196 degrees C. These changes were attributed to adverse osmotic conditions. Binding of cationic ferritin to the plasmalemma of spermatozoa from both species remained unaltered.     

A revision of Cycniopsis (Scrophulariaceae)

The genus Cycniopsis is reexamined. Generic and specific delimitation is discussed with respect to morphological characters, including seed structures studied by scanning electron microscopy. A hierarchical key to Cycniopsis and related genera is presented.
Two species are recognised, C. humifusa and C. humilis comb. nov. Several names are reduced to synonymy, and three lectotypes and one neotype are selected. Both species are illustrated, and a distribution map is provided.     

Further studies on Nephroselmis and its allies (Prasinophyceae). I. The question of the genus Bipedinomonas

Based on a series of collections made in New Zealand it is concluded that Nephroselmis longifilis and Bipedinomonas pyriformis are identical species, for which the correct name is Nephroselmis pyriformis (N. Carter) comb. nov. A detailed examination by light and electron microscopy is given, using material from geographically widely separated areas, including Greenland, the North Sea, a shallow Danish Fiord, Thailand and New Zealand. N. pyriformis is a temperature– and halotolerant species, as shown by its known range of occurrence at temperatures from 2.3°C (West Greenland) to ca. 28°C (Thailand) and at salinities between 3 and 36%o. Features of fine structural interest include details of the scaly covering on the flagellar and cell surfaces, the former very similar to those on the flagella of Tetraselmis cordiformis , a quadriflagellate prasinophyte. Within the cell, the pyrenoid shows an unusual fine structure, being penetrated by a number of membrane–lined pockets, in which the membranes are continuous with thylakoids. N. pyriformis is compared with other members of the genus, and a list of the few known species is included.