Kinetics of pleuridial growth in Antithamnion plumula (Rhodophyceae)

The filamentous and branched thallus of Antithamnion plumula is constitued of two different kinds of branches with apical growth: the cladomial axes with a continuous or indefinite growth, and the pleuridia with a limited growth. The size of the pleuridia depends on their position with respect to the lateral cladomial axes.The growth kinetics of 35 pleuridia were analysed using Nelder's generalized logistics. Each sigmoidal curve, which was divided into four growth stages from the instantaneous acceleration variations, was thus characterized by ten kinetic parameters: lengths at the time of the changes in growth stage, durations of the growth stages and maximum growth rate.The data showed that all curves displayed a marked left dissymmetry which reflected the brevity of the accelerated growth stage (1/5 of total growth duration). The maximum acceleration stage occurs between the individualization of the pleuridial initial cell and the first mitosis. Previously known experimental data were related to this quantitative result so as to put forward a biological meaning. New research pathways were suggested.The kinetic parameters investigated were used for a classification of pleuridia. The smallest ones displayed the slowest growth: they needed twice more time to reach their maximum size than the largest pleuridia whose growth was the fastest. This association of traits was related to the occurrence of acropetal fluxes along the main axis of the thallus.     

Simulation of the Thallus Development of Antithamnion Plumula (Ellis) Le Jolis, (Rhodophyceae, Ceramiales)

The development of the typical cladomothallus of the red algae Antithaminion plumula (Ellis) Le Jolis [= Pterothamnion plumula (Ellis) Nägcli], (Rhodophyceae, Ceramiales) is simulated with the help of a formal language called L-systems. Two types of uniseriate filaments are distinguished: axial filaments of cladomes with indefinite growth and branching and pleuridia with definite growth and branching. The rythmical acropetal formation of secondary axes with basitonic arrangement contrasts with the intercalary basitonic formation of pleuridia, resulting in an acrotonic arrangement within an axial segment. Five types of cells and two types of cell divisions intervene in the system. In addition, for the graphical representations, some morphological particularities of A. plumula are taken into account: the curvature of axial filaments, the extension of growth zones, variable cell generation times, and segment length variability along an axis. The incidence of these variables on the generated thallus form is emphasized, pointing to the singularities of A. plumula.     

Cage culture ofKappaphycus alvarezii var.tambalang (Gigartinales,Rhodophyceae)

Kappaphycus alvarezii var.tambalang was cultured in a 3 × 3 m bamboo raft installed inside a 4 × 4 m floating net cage ofLates calcarifer (sea bass) broodstock at SEAFDEC Sub-station Igang, Guimaras, Philippines, from December 1989 to May 1990. Growth and production ofK. alvarezii var.tambalang was influenced by the culture months. The highest growth rate and production were recorded in January and May, respectively, while the lowest growth rate and production were observed in March. Average growth rate (wet weight) ranged from 3.72 to 7.17% day^-1, while production ranged from 575.5 to 2377 g m^-1 line^-1. A total production of approximately 123 t (fresh) or 37 t (dried) ha^-1 in the 5-month harvest season was produced from this culture system. Cultivation ofK. alvarezii var.tambalang in cages is possible, which indicates that seaweeds can be grown with carnivorous finfish, a practice which is still untapped.     

Antithamnion makroklonion sp. nov. (Rhodophyta, Ceramiales) from the Gulf of Aqaba (Red Sea)

Antithamnion makroklonion sp. nov. is described from Elat, Gulf of Aqaba (Gulf of Elat) in the Red Sea, where vegetative, spermatangial, and tetrasporangial specimens were found growing in the upper sublittoral zone. The new alga belongs to a group of Antithamnion species characterized by distichous-alternate ramification of branches, sessile tetrasporangia, and decussately arranged laterals along the bearing axis. It shows a unique combination of distinctive features, including the proximal development of gland cells on elongate branchlets that overtop the parent branch. In addition to the characteristic position, and in contrast to congeners, gland cells of A. makroklonion often have a large and prominent cytoplasmic band and one or two vacuoles. Morphological features of A. makroklonion and eight related species are tabulated and the characteristics of the new species are discussed.     

Mallomonas corymbosa var. interrupta nov. var. (Synurophyceae) from Argentina

A new variety of Mallomonas corymbosa is described from a pond in Nahuel-Huapi National Park (Argentina): M. corymbosa var. interrupt nov. var. Fine structure of scales and bristles has been studied by scanning and transmission electron microscopy.     

Descriptions of three Pristina species (Naididae,Clitellata) from Amazonian forest soils,including P. marcusi sp. nov.

Hydrobiologia - Three species of the oligochaete genus Pristina (Naididae, Clitellata), one of them new to science, are described from soil and litter samples originating from terra firme sites of...     

A review of the Gymnostomum calcareum Nees & Hornsch. complex (Bryopsida: Pottiaceae) in southern Europe and the Macaronesian Islands,including G. calcareum var. atlanticum var. nov.

Abstract

New taxonomic observations, based on rhizoidal and protonemal gemmae of material from southern Europe and the Macaronesian Islands, are given in this work for sibling taxa of the Gymnostomum calcareum Nees & Hornsch. complex. Gymnostomum calcareum var. atlanticum Sérgio from the Iberian Peninsula, Madeira and Azores is described as a new variety, and its diagnostic characters are described and illustrated. This moss has a bistratose margin in the upper parts of the perichaetial and vegetative leaves, and the perichaetial leaves are markedly acute. It is closely related to Gymnostomum lanceolatum Cano, Ros & J. Guerra, here reduced to a variety of G. calcareum. The occurrence of fusiform or claviform protonemal gemmae provides a diagnostic feature for the different taxa.     

Life history and taxonomy ofCricosphaera roscoffensis var.haptonemofera,var. nov. (class prymnesiophyceae) from the pacific

A new coccolithophoridCricosphaera roscoffensis var.haptonemofera is described by means of electron microscopy and with the aid of laboratory culture. The living specimens, which were in the motile phase, were collected in Okinawa, a subtropical region in Japan, and a unialgal culture was established in the laboratory. The life history was observed, starting from the motile cells. The life history consists of two phases: the motile phase and the benthic filamentous phase. The former is unicellular and presumably a diploid sporophyte, whereas the latter is similar to an alga previously known as “Apistonema submarinum” described by Dangeard (1934), and probably a haploid gametophyte. The motile cells bear two acronematic flagella and one short haptonema. The scales attached on the surface of the motile cells are of two kinds: one is an organic thin scale, and the other is a cricolith, a kind of coccolith, the latter being structurally almost identical with that ofCricosphaera roscoffensis studied by Gayral and Fresnel (1976). Because this species has neither haptonema nor a benthic filamentous phase, we propose, at present, to treat this alga as a new taxon at the rank of infraspecies, naming itCricosphaera roscoffensis var.haptonemofera Inouye et Chihara.     

Pinus contorta var. yukonensis var. nov. (Pinaceae) from south–central Yukon,Canada

Pinus contorta Douglas ex Loudon var. yukonensis W. L Strong (Yukon pine), a new variety, is described from south–central Yukon, Canada. It is a stout tree with long lower branches, often with paired lower and forked upper stems, and weakly platy to smooth gray bark on the lower stem, when < 70 years old; with bark on the lower stem becoming furrowed and platy on older trees. This contrasts with the narrow columnar habit, simple stem, and scaly bark associated with the more common inland var. latifolia. In several respects, var. yukonensis is more similar to var. contorta (a coastal variant), although occupying a different ecological regime and spatially disjunct (i.e., a high latitude and high elevation variant). Variety yukonensis may represent the taxon alluded to in previous leaf oil terpene and genetic studies, and a possible Beringian survivor.     

Morphology and SSU rRNA gene sequences of three Frontonia species,including a description of F. subtropica spec. nov. (Ciliophora,Peniculida)

The morphology and infraciliature of three Frontonia species, F. subtropica spec. nov., F. canadensis Roque and Puytorac, 1972, and F. magna Fan et al., 2011, isolated from coastal waters in southern China sea, were investigated using living observation and silver impregnation methods. Frontonia subtropica spec. nov. is recognized by the combination of the following characters: body elliptical in outline with right margin depressed in anterior third, about 180–230 μm × 60–80 μm in vivo; 104–114 somatic kineties; peniculi 1–3 each with four kineties; five vestibular and five postoral kineties; one centrally located elongate-elliptical macronucleus; single contractile vacuole located left-dorsally in posterior third of body. We also provide improved diagnoses for F. canadensis and F. magna based on current and previous reports. The small subunit (SSU) rRNA gene was sequenced for all three species. Comparisons with sequences of morphologically similar congeners clearly support the validity each species.     

Taxonomy and molecular systematics of three oligotrich (s.l.) ciliates including descriptions of two new species,Strombidium guangdongense sp. nov. and Strombidinopsis sinicum sp. nov. (Protozoa,Ciliophora)

In this study we investigated the morphology of three oligotrich (s.l.) ciliates, Strombidium guangdongense sp. nov., Cyrtostrombidium paralongisomum Tsai et al., 2015 and Strombidinopsis sinicum sp. nov. Strombidium guangdongense sp. nov. is characterized by its elongate obconical to obovoidal body shape and widely spaced dikinetids in the girdle and ventral kineties. Another new species, Strombidinopsis sinicum sp. nov. is diagnosed by its small size and semi-globular body shape without mineral envelopes. Some additional morphological data of the recently described species Cyrtostrombidium paralongisomum Tsai et al., 2015, such as the endoral membrane, are supplied based on our population. We also analysed the molecular phylogeny of each species based on small subunit rRNA (SSU rRNA) gene sequence data. The monophyly of Cyrtostrombidium is supported by our phylogenetic analyses, but the monophyly of Strombidinopsis and of the family Strombidinopsidae are both rejected by AU tests. In addition, Strombidium species have a tail branch separately from one another in phylogenetic trees, whereas strombidiids with a pigment spot group together, suggesting the latter character is a synapomorphy for this group of strombidiids.

http://zoobank.org/urn:lsid:zoobank.org:act:35FE2AFD-A582-4885-BD01-48901E4C76C4

http://zoobank.org/urn:lsid:zoobank.org:act:E9D4A497-DAD6-4AA0-A044-A5A1D2C1A057     

Blidingia minima var. stolonifera var. nov. (Ulvales, Chlorophyta) from British Columbia: systematics, life history and morphogenesis

Blidingia minima var. stolonifera var. nov. is described from Vancouver, British Columbia. In previous literature this variety may have been confused with B. chadefaudii and B. minima var. minima. The new variety is part of the B. minima species complex in which spores germinate by evacuating the original spore and forming a germ tube. B. minima var. stolonifera is characterized by the development of marginal filaments on the basal disc that have one to five colourless cells and terminate in a cell from which a new disc grows. Colourless cells are devoid of chloroplasts and nuclei, and contain only small remnants of cytoplasm. The runner system is considered a mechanism of vegetative growth and propagation that enables a disc to cover a large amount of substratum before producing erect, unbranched thalli. In field and in culture, B. minima var. stolonifera typically reproduces by means of quadriflagellate zoospores; however, three plants from Vancouver formed biflagellate spores. These germinated poorly and developed into highly irregular, branched thalli.     

A comparative study of bark lectins from three elderberry (Sambucus) species

Three elderberry lectins isolated from the bark of three different species of the genus Sambucus which are native to Europe (S. nigra), North America (S. canadensis), and Japan (S. sieboldiana) were studied comparatively with regard to their carbohydrate binding properties and some structural features. All three lectins contained two identical carbohydrate binding sites per molecule and showed a very high specificity for the Neu5Ac(alpha 2-6)-Gal/GalNAc sequence. However, relative affinities for various oligosaccharides were significantly different among them, suggesting differences in the detailed structure of the carbohydrate binding sites of these lectins. The three lectins were immunologically related, but not identical, and all were composed of hydrophobic and hydrophilic subunit regions, although the molecular sizes of these subunits were slightly different among the three lectins. N-terminal sequence analysis of the subunits of these lectins suggested that they have a very similar structure in this region but also indicated the occurrence of N-terminal processing such as the deletion of several amino acid residues at the N-termini for both hydrophobic and hydrophilic subunits of all three lectins. Tryptic peptide mapping of the three lectins showed a similar pattern for all of them but also showed the presence of some unique peptides for each lectin.     

Morphology and phylogenetics of Stomatisora,including Stomatisora psychotriicola sp. nov.

The morphology of the type specimen of Stomatisora geophilicola, the only species of the genus Stomatisora (Pucciniales) recognised till now, was restudied. Thin-walled probasidia (teliospores) develop exclusively in substomatal chambers, and mature metabasidia emerge through the stomata and develop suprastomatally. Uredinia are erumpent through the upper epidermis. A new species, S. psychotriicola, parasitizing Psychotria capensis (Rubiaceae) from South Africa, is described and illustrated. Only telia have been found which also develop in stomatal cavities, and, as in the type species, have partly repetitive probasidia and suprastomatal metabasidia that easily detach from fragile stalks. The similarities of telial morphology, as well as the same host family, indicate a close relationship and a generic separation from other rust genera. Molecular data support this interpretation and a possible relationship within a phakopsoroid clade.     

A taxonomic study of the Spirillum lipoferum group, with descriptions of a new genus, Azospirillum gen. nov. and two species, Azospirillum lipoferum (Beijerinck) comb. nov. and Azospirillum brasilense sp. nov.

Sixty-one strains of the root-associated nitrogen fixer Spirillum lipoferum exhibited a similar morphology in peptone--succinate salts medium: vibrioid cells having a diameter of 1.0 micrometer. When grown in broth the cells had a single polar flagellum, but when grown on agar at 30 degrees C lateral flagella of shorter wavelength were also formed. The DNA base composition was 69--71 mol% guanine + cytosine when determined by thermal denaturation. DNA homology experiments indicated the occurrence of two distinct but related homology groups: 46 strains were in group I and 15 strains were in group II. Group II strains were distinguished by their ability to use glucose as a sole carbon source for growth in nitrogen-free medium, by their production of an acidic reaction in a peptone-based glucose medium, by their requirement for biotin, and by their formation of wider, longer, S-shaped or helical cells in semisolid nitrogen-free malate medium. The results indicate that two species exist, and on the basis of their characteristics it is proposed that they be assigned to a new genus, Azospirillum. Strians belonging to group II are named A. lipoferum (Beijerinck) comb. nov., while those belonging to group I are named A. brasilense sp. nov. Strain Sp 59b (ATCC29707) is proposed as the neotype strain for A. lipoferum, and strain Sp 7 (ATCC 29145) is proposed as the type strain for A. brasilense.     

Paraurosomoida indiensis gen. nov., sp. nov., an oxytrichid (Ciliophora,Hypotricha) from Kyongnosla Alpine Sanctuary,including note on non-oxytrichid Dorsomarginalia

Paraurosomoida indiensis gen. nov., sp. nov. was isolated from a soil sample collected from Kyongnosla Alpine Sanctuary in the Eastern Himalayas. The present study reports the morphology, morphogenesis, and molecular phylogeny inferred from 18S rDNA sequence. The study is based on live and protargol-impregnated specimens. Paraurosomoida indiensis is very flexible, measures about 90 × 25 μm in life and possesses citrine cortical granules randomly distributed singly and in small linear groups. Paraurosomoida indiensis has undulating membranes nearly in Oxytricha pattern; only 11 frontal-ventral cirri due to lack of all pretransverse ventral and transverse cirri; one dorsomarginal row and three bipolar dorsal kineties. Divisional morphogenesis resembles oxytrichids involving six parental cirri in primordia formation. Anlagen V and VI for both proter and opisthe are formed from two primary primordia originating from disaggregated cirri V/4 and V/3 respectively. Three dorsal kineties develop from within row anlagen without a kinety 3 fragmentation. Molecular analyses consistently place P. indiensis with soft bodied oxytrichids.     

Culture studies of Acrochaete leptochaete comb. nov. and A. wittrockii comb. nov. (Chaetophoraceae, Chlorophyceae)

A culture study of the plants known as Phaeophila leptochaete (Huber) Nielsen and P. wittrockii (Wille) Nielsen proved that these are distinct species. Both have the Acrochaete type of hairs, and therefore, the new combinations Acrochaete leptochaete and A. wittrockii are introduced. Several isolates of both species were started from plants collected at different places in Europe.
A. leptochaete in culture was mainly characterised by having two or more (up to six) pyrenoids in many of its cells, while in A. wittrockii there invariably was only one. The swarmers formed by A. leptochaete had two or four flagella. Several hairs from one basal swelling were sometimes observed in one of the isolates. Another isolate often formed a hair on the germinated zoospore. The isolates of A. wittrockii had a variable morphology, from unicellular plants to large pseudoparenchymatous cell masses. Different kinds of swarmers were observed; zoospores with three flagella seemed typical, but ones with two or four flagella were also observed. Small, pale biflagellate swarmers were assumed to be gametes. One of the isolates of A. wittrockii differed from the rest as the only swarmer type observed was zoospores with two flagella. Chlorophilum ephemerum is considered identical to A. wittrockii. Observations on hair formation in A. repens suggested that the hair structure represents a separate cell.