Ultrastructure and molecular phylogeny of thaumatomonads (Cercozoa) with emphasis on Thaumatomastix salina from Oslofjorden, Norway

A culture of Thaumatomastix was isolated from a sediment sample collected in Oslofjorden and established as a monospecific strain (UIO286). Based on this culture, light and transmission electron microscopy and phylogenetic analyses were carried out. Thaumatomastix species are confined within the order Thaumatomonadida of the class Imbricatea and phylum Cercozoa. They are heterotrophic and their cell bodies are covered with silica scales. Observations of thin sections as well as whole mounts indicate that the morphology and ultrastructure of UIO286 is identical to T. salina, which was initially described from salt pools in Denmark. Detailed examination revealed some new features such as the presence of pseudopodia and silica deposition vesicles producing spine scales. The phylogeny presented here includes ribosomal DNA sequences from both imbricatean cultures and environmental samples. The 18S rDNA phylogenetic tree suggests that (i) Thaumatomastix is paraphyletic within the Thaumatomonadida clade, (ii) there is no close affinity between T. salina and other cultured and sequenced strains, but it is closely related to a sequence obtained from environmental DNA; we propose the present strain to serve as a reference culture of Thaumatomastix species and T. salina. Further, we discuss the distribution, habitats, and evolution of scale formation among euglyphids and thaumatomonads.     

Haligena salina: a new marine pyrenomycete

EARRANT, C. A. & JONES, E. B. G., 1986. Haligena salina: a new marine pyrenomycete. Haligena salina sp. Nova (Ascomycotina, Sphaeriales, Halosphaeriaceae) collected on wood from San Juan Island, Washington State, U.S.A., and on reeds from Pisa, Italy is described. The species is compared with Haligena elaterophoraj. Kohlmeyer and species in the genus Remispora Linder.     

Observations on Chrysophyceae from a Norwegian mountain lake

Chrysosphaerella coronasircumspina Wujek & Kristiansen and Spiniferomonas bilacunosa Takahashi have been shown by electron microscopy to be regular members of the phytoplankton society in an oligotrophic Norwegian mountain lake. This is the first published record of these species in Norway.     

Enhygromyxa salina gen. nov., sp. nov., a slightly halophilic myxobacterium isolated from the coastal areas of Japan

Six isolates of novel marine myxobacteria, designated strains SHK-1T, SMK-1-1, SMK-1-3, SMK-10, SKK-2, and SMP-6, were obtained from various coastal samples (mud, sands and algae) collected around Japan. All of the isolates had Gram-negative rod-shaped cells, motile by gliding and grew aerobically. They showed bacteriolytic action, fruiting body formation, and NaCl requirement for growth with an optimum concentration of 1.0-2.0% (w/v). In addition, divalent cationic components of seawater, such as Mg2+ or Ca2+, were also needed for growth. The major respiratory quinone was MK-7. The G+C content of genomic DNA ranged from 65.6 to 67.4 mol% (by HPLC). The isolates shared almost identical 16S rDNA sequences, and clustered with a recently described marine myxobacterium, Plesiocystis pacifica, as their closest relative on a phylogenetic tree (95.9-96.0% similarity). Physiological and chemotaxonomic differences between the new strains and strains of the genus Plesiocystis justify the proposal of a new genus. Therefore, we propose to classify the six isolates into a new taxon of marine myxobacteria with the name, Enhygromyxa salina gen. nov., sp. nov. The type strain is SHK-1(T) (JCM 11769(T) = DSM 15217(T) = AJ 110011(T)).     

Ultrastructure and taxonomy of Paraphysomonas (Chrysophyceae) and related genera 2

This is the second of two accounts reporting on the occurrence and systematics of freshwater species of the colourless chrysophycean genus Paraphysomonas in the Cambridge area, using electron microscopy of whole mounts of both cells and scales and sections of scales. Twenty species are included here, eleven of which are new: P. cancellala, P. canistrum, P. homolepis, P. ignivoma, P. limbata, P. morchella, P. runcinifera, P. stelligera, P. stephanolepis, P. subquadrangularis and P. undulata. Five new subspecies are also established: P. circumvallata ssp. mediogranulata, P. poteriophora ssp. manubriata, P. punctata ssp. atrema , ssp. microlepis and ssp. simplicior. P. diademifera (Takahashi) comb. nov. [= Lepidochromonas diademifera (Takahashi) Kristiansen] has been included in Paraphysomonas since it has been found to be colourless and not pigmented as originally described and also to possess scales of a similar structure to those in other species of Paraphysomonas. One previously described species, P. inconspicua Takahashi, is here considered as a synonym of P. butcheri Pennick & Clarke. P. vacuolata Thomsen is removed from Paraphysomonas since it has been found to possess a chloroplast and will be included in a new genus in the third paper of this series. The 37 presently known species of Paraphysomonas have been arranged in 11 different groups according to similarities in scale structure. Consideration of the possible evolution of scale structure in Paraphysomonas and the possible interrelationships within the genus led to the conclusion that all species should be included in a single genus.     

Sicilica-scaled chrysophytes from Korea, a preliminary study

Phytoplankton samples obtained from 10 localities in Korea (Democratic People's Republic of Korea, DPRK) have been examined by means of electron microscopy. 27 species of silica-scaled chrysophytes (Chrysophyceae and Synurophyceae) have been identified, belonging to the genera Chrysosphaerella, Spiniferomonas, Paraphysomo-nas, Mallomonas , and Synura. Almost all of these species are new to Korea, only two of them have with certainty been found there before.     

Scale-bearing Chrysophyceae (Mallomonadaceae and Paraphysomonadaceae) from West Greenland

Phytoplankton samples from twenty-one freshwater localities in the area of Nuuk (Godthåb), West Greenland, have been examined by means of electron microscopy in order to investigate the flora of scale bearing Chrysophyceae. Forty-two taxa of the genera Mallomonas, Synura, Chromophysomonas (Spiniferomonas), Chrysosphaerella and Paraphysomonas have been observed, and thirty-eight of these are illustrated by TEM or SEM micrographs. Thirty-four of the observed taxa, among these all members of the genus Chromophysomonas , are for the first time recorded from Greenland. Chromophysomonas involuta sp.nov. is described. The scale morphology of the Greenlandic specimens is compared with earlier findings from other parts of the world, and the most remarkable features of the chrysophycean flora from the investigated area are discussed.     

A phylogenetic study of the genus Haligena (Halosphaeriales, Ascomycota)

The genus Haligena (Halosphaeriales, Ascomycota), with two accepted species, is encountered frequently in marine habitats, especially on wood in temperate regions. Phylogenetic analyses of Haligena elaterophora (type species) and H. salina were undertaken, with partial large subunit ribosomal DNA sequences, to determine their relationships with other closely related genera in the order. The genus was shown to be polyphyletic within the Halosphaeriales with the type species forming a basal clade to the order. Haligena salina constituted a sister clade with weak support of Neptunella longirostris in all analyses. Haligena elaterophora and H. salina differ significantly in the nature of their ascospore appendages: wider, more sticky and strap-like in H. elaterophora and spoon-shaped at the point of attachment; in H. salina they are longer and narrower, finely drawn out filaments. A new genus, Morakotiella, is introduced to accommodate H. salina.     

A unique radiation of marine littorinid snails in the freshwater streams of the Western Ghats of India: the genus Cremnoconchus W.T. Blanford, 1869 (Gastropoda: Littorinidae)

The caenogastropod family Littorinidae is almost exclusively marine, but a unique freshwater genus, Cremnoconchus, is known from India. Its members are restricted to montane streams on the western escarpment of the Western Ghats, at altitudes between 300 and 1400 m. Four species and several varieties were described in the 19th century, but no taxonomic study has been carried out for over 120 years and the last anatomical report was in 1935. Nevertheless, they are of unusual evolutionary interest and also of conservation concern as a genus endemic to the Western Ghats biodiversity hotspot. Based on anatomical study of newly collected material and examination of historical and type specimens, we present a systematic revision of Cremnoconchus, illustrating shells, radulae, and reproductive anatomy. The very large eggs, invaginated penial filament, and calcified operculum are unique among Littorinidae. Three valid, described species (C. syhadrensis, C. conicus, C. canaliculatus) are recognized in the northern Western Ghats in Maharashtra state, where all can occasionally be found sympatrically. We describe an additional six new species from the central Western Ghats in a small area (linear distance 80 km) of Karnataka state, over 500 km south of the previously known range of the genus. Here the species each appear to be restricted to a single drainage system. Because of their highly restricted distribution and fragile habitat, this radiation of nine species is judged to be endangered. © 2013 The Linnean Society of London     

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。     

Silica-scaled Chrysophytes from Portugal

Phytoplankton samples from lakes, reservoirs and ponds in Central Portugal were obtained and the scale-bearing chrysophytes investigated by electron microscopy. This is the first study on the occurrence and distribution of these organisms in Portugal and in the Iberian Peninsula as a whole. It reports the presence of 23 species of the genera Chrysosphaerella, Paraphysomonas, Spiniferomonas, Mallomonas and Synura . Most of the species found are of worldwide distribution but a few rare organisms were present in some samples. To conclude, the perspectives of future research in Portugal are briefly outlined.     

PRESENCE OF A SECOND FLAGELLUM IN CHRYSOSPHAERELLA MULTISPINA1

The genus Chrysosphaerella, originally described by Lauterborn as having a single flagellum and later emended by Korshikov who observed a second flagellum, was studied using the electron microscope. Electron micrographs confirm Korshikov's observation ivhich in most recent classification schemes has been overlooked,     

Relation between habitat and antennular segmentation in Gammarus and Echinogammarus (Crustacea: Amphipoda)

In 140 species of the amphipod genera Gammarus and Echinogammarus the ratio was calculated between the number of segments of the accessory and main antennular flagellum. Minor inter-and intrapopulational variation of this ratio was found in four species of the genus Gammarus. Seasonal variation was studied in one species of this genus. For both genera a clear correlation was found between antennular composition and the occurrence in marine or freshwater habitats.     

The validity of the genus Spiniferomonas (Chrysophyceae)

Cells of Spiniferomonas bourrellyi Takahashi have been shown to possess a chloroplast. A procedure for examining the same cells by both light and electron microscopy was developed so that the structure of silica scales (which is diagnostic for the species) could be confirmed for cells clearly possessing chloroplasts. A previously published proposal invalidated the genus Spiniferomonas because the type species ( S. bourrellyi ) was found to be colourless and the new genus Chromophysomonas was erected to include all remaining pigmented species of Spiniferomonas . The findings reported here support reinstatement of S. blurrily as the validated type of the genus; Chromophysomonas is considered a redundant synonym.     

Pancreatonema torriensis gen. nov., sp. nov. (Nematoda: Rhabdochonidae) from the pancreatic duct of Raja naevus

A new genus and species of nematode, Pancreatonema torriensis, from the pancreatic duct of Raja naevus caught off Aberdeen and north-west Scotland is described and aspects of its biology are discussed. According to the classification of Skrjabin, Sobolev & Ivashkin (1967) [Spirurata of animals and man and the diseases caused by them (4). Essentials of Nematodology, Vol. 16 (I.P.S.T. Translation No. 5904, Jerusalem, 1971)]it belongs to the family Rhabdochonidae, sub-family Prosungulonematinae, and is closely related to the genus Johnstonmawsonia. The taxonomy of the Prosungulonematinae is confused but it is suggested that Johnstonmawsonia should at present be restricted to those species of the genus described from marine teleosts, and that the species from freshwater teleosts should be included in the genus Prosungulonema.     

Carbon source utilization by the marine Dendryphiella species D. arenaria and D. salina

Carbon utilization by the marine Dendryphiella species, D. arenaria and D. salina, was investigated to detect differences in utilization and traits associated with their adaptation to the marine habitat. Fifty-four strains were isolated world-wide and tested for the utilization of various carbon sources using BIOLOG phenotype MicroArray (PM) and for the production of extracellular enzymes on solid culture media and on API ZYM assay strips. PM analysis showed that the fastest growth occurred on several monosaccharides and amino acids, 2-keto-d-gluconic acid, succinamide and turanose. Some polyols were poor carbon sources. However, the two species differed in their utilization rates of carbon sources, forming three major clusters: two separate clusters for D. arenaria and D. salina and a third cluster in which strains of the two species formed separate subclades that correlated with geographic origin. Several carbon sources were also found useful in differentiating the two speices. Dendryphiella salina did not utilize xylitol and quinic acid, whereas D. arenaria grew well on these substrates. The latter failed to grow on sorbitol and grew slowly on mannitol, both were good substrates for the former. There were also no qualitative differences between the extracellular enzymes produced, although laccase and peroxidase activities were confined only to some strains. The physiological similarities exhibited by the two species support the close relationship between D. arenaria and D. salina.     

Pigment-Based Chemotaxonomy - A Quick Alternative to Determine Algal Assemblages in Large Shallow Eutrophic Lake?

Pigment-based chemotaxonomy and CHEMTAX software have proven to be a valuable phytoplankton monitoring tool in marine environments, but are yet underdeveloped to determine algal assemblages in freshwater ecosystems. The main objectives of this study were (1) to compare the results of direct microscopy and CHEMTAX in describing phytoplankton community composition dynamics in a large, shallow and eutrophic lake; (2) to analyze the efficiency of the pigment-based method to detect changes in phytoplankton seasonal dynamics and during rapid bloom periods; (3) to assess the suitability of specific marker pigments and available marker pigment:chlorophyll a ratios to follow seasonal changes in eutrophic freshwater environment. A 5-year (2009-2013) parallel phytoplankton assessment by direct microscopy and by CHEMTAX was conducted using published marker pigment:chlorophyll a ratios. Despite displaying some differences from microscopy results, the pigment-based method successfully described the overall pattern of phytoplankton community dynamics during seasonal cycle in a eutrophic lake. Good agreement between the methods was achieved for most phytoplankton groups - cyanobacteria, chlorophytes, diatoms and cryptophytes. The agreement was poor in case of chrysophytes and dinoflagellates. Our study shows clearly that published marker pigment:chlorophyll a ratios can be used to describe algal class abundances, but they need to be calibrated for specific freshwater environment. Broader use of this method would enable to expand monitoring networks and increase measurement frequencies of freshwater ecosystems to meet the goals of the Water Framework Directive.