Andrzej Massalski

NEW STREPTOPHYTE GREEN ALGAE FROM TERRESTRIAL HABITATS AND AN ASSESSMENT OF THE GENUS INTERFILUM (KLEBSORMIDIOPHYCEAE, STREPTOPHYTA)(1).

Sarcinoid aeroterrestrial green algae were isolated from three arid locations in Ukraine and the Czech Republic. Although gross morphology suggested an affinity with Desmococcus (for taxonomic authorities, see Table S1 in the supplementary material), the cellular morphological characteristics were reminiscent of those of Geminella terricola. However, the presence of a complex of ultrastructural features indicated that these isolates were members of the streptophyte lineage in the green plants. 18S rDNA sequence phylogenies provided evidence of a close relationship with Klebsormidium in the Streptophyta, while the position of Desmococcus was within the Trebouxiophyceae. In the internal transcribed spacer (ITS) rDNA phylogeny, the sarcinoid isolates were closely related with strains of G. terricola and Interfilum paradoxum. Strains of that clade were morphologically united by a specific type of cell division that involves the association of persistent, cap‐shaped remains of the mother cell wall with daughter cells. Consequently, these strains were assigned to a redefined genus Interfilum, and a new species, I. massjukiae, was described to accommodate one of the sarcinoid isolates. As the position of the genus Geminella was in the Trebouxiophyceae, the streptophyte G. terricola was transferred to Interfilum, as I. terricola comb. nov., but the ITS rDNA analyses proved inconclusive to resolve its affinities with other species of Interfilum due to intragenomic polymorphisms. The species of Interfilum had a closer relationship with K. flaccidum than with other species of Klebsormidium. The latter genus may not be monophyletic in its present circumscription.

Testing for endemism, genotypic diversity and species concepts in Antarctic terrestrial microalgae of the Tribonemataceae (Stramenopiles, Xanthophyceae)

The genetic diversity of all available culture strains of the Tribonemataceae (Stramenopiles, Xanthophyceae) from Antarctica was assessed using the chloroplast-encoded psbA /rbcL spacer region sequences, a highly variable molecular marker, to test for endemism when compared with their closest temperate relatives. There was no species endemic for Antarctica, and no phylogenetic clade corresponded to a limited geographical region. However, species of the Tribonemataceae may have Antarctic populations that are distinct from those of other regions because the Antarctic strain spacer sequences were not identical to sequences from temperate regions. Spacer sequences from five new Antarctic isolates were identical to one or more previously available Antarctic strains, indicating that the Tribonemataceae diversity in Antarctic may be rather limited. Direct comparisons of the spacer sequences and phylogenetic analyses of the more conserved rbcL gene revealed that current morphospecies were inadequate to describe the actual biodiversity of the group. For example, the genus Xanthonema, as currently circumscribed, was paraphyletic. Fortunately, the presence of distinctive sequence regions within the psbA/rbcL spacer, together with differences in the rbcL phylogeny, provided significant autoapomorphic criteria to re-define the Tribonemataceae species.

Morphology and ultrastructure of Interfilum and Klebsormidium (Klebsormidiales, Streptophyta) with special reference to cell division and thallus formation

Representatives of the closely related genera, Interfilum and Klebsormidium, are characterized by unicells, dyads or packets in Interfilum and contrasting uniseriate filaments in Klebsormidium. According to the literature, these distinct thallus forms originate by different types of cell division, sporulation (cytogony) versus vegetative cell division (cytotomy), but investigations of their morphology and ultrastructure show a high degree of similarity. Cell walls of both genera are characterized by triangular spaces between cell walls of neighbouring cells and the parental wall or central space among the walls of a cell packet, exfoliations and projections of the parental wall and cap-like and H-like fragments of the cell wall. In both genera, each cell has its individual cell wall and it also has part of the common parental wall or its remnants. Therefore, vegetative cells of Interfilum and Klebsormidium probably divide by the same type of cell division (sporulation-like). Various strains representing different species of the two genera are characterized by differences in cell wall ultrastructure, particularly the level of preservation, rupture or gelatinization of the parental wall surrounding the daughter cells. The differing morphologies of representatives of various lineages result from features of the parental wall during cell separation and detachment. Cell division in three planes (usual in Interfilum and a rare event in Klebsormidium) takes place in spherical or short cylindrical cells, with the chloroplast positioned perpendicularly or obliquely to the filament (dyad) axis. The morphological differences are mainly a consequence of differing fates of the parental wall after cell division and detachment. The development of different morphologies within the two genera mostly depends on characters such as the shape of cells, texture of cell walls, mechanical interactions between cells and the influence of environmental conditions.

Biodiversity of Limestone Caves: Aggregations of Aerophytic Algae and Cyanobacteria in Relation to Site Factors

ABSTRACT The most numerous limestone caves are in the smallest national park in Poland (the Ojców National Park). A total of 50 algal samples were collected from ten caves, each having different environmental factors such as light intensity, temperature and humidity. The morphological and ecological variability of cyanobacteria and algae were studied using fresh samples, cultures grown on agar plates, and documented with TEM, SEM and LM. Light microscopic observations showed that aerophytic cyanobacteria were the most important component of the cave′s photosynthetic microflora. Among cyanobacteria, the following genera were frequently encountered: Aphanocapsa, Chroococcus, Gloeocapsa, Leptolyngbya, and Synechocystis. Whereas the green algal genera, Apatococcus and Klebsormidium, often occurred with Chlorella, Muriella, Neocystis and the diatoms, Orthoseira and Pinnularia. Most of the algal species appeared to be cosmopolitan, ubiquitous, had simple nutrition requirements and wide ecological tolerance (they reproduced rapidly and were easily adaptable to new conditions). The cave′s microhabitats offered relatively stable microclimatic conditions and they seemed to be responsible for the observed distribution of aerophytic algae and cyanobacteria. The Shannon-Wiener index (H′) ranged between 4.9 and 3.9, and the Kruskal-Wallis test showed that these differences were statistically significant.

Mitosis, cytokinesis and multinuclearity in a Xanthonema (Xanthophyta) isolated from Antarctica

The ultrastructure of a Xanthonema strain featuring multinucleate cells was investigated by transmission electron microscopy. An important specific feature of the organisation of the photosynthetic apparatus in this strain is its association with mitochondrial profiles. The chloroplast girdle is composed of two different U-shaped lamellae, one peripheral and one subcentral. Multinuclearity is observed as often as the uninucleate state. The transition from the uninucleate to the multinucleate stage is connected to disturbances in the normal division pattern of the parietal chloroplast-mitochondria complex during interphase. As a result mitosis is not coordinated with cytokinesis. The return to the uninucleate stage occurs as a result of asynchronous cytokinesis or by aplanospore formation. Mitosis is of the semi-closed type, as in Tribonema. Centrioles replicate in early interphase, after the end of karyokinesis and progeny nuclei separate with the aid of CER invagination. Filament fragmentation takes place between neighbouring cells where two U-shaped segments adjoin, resulting in fragment ends being rounded rather than ‘zweispitzig’. The taxonomic significance of various ultrastructural features for the classification of filamentous Xanthophyta is discussed.

Relationships between diatoms and environmental variables in industrial water biotopes of Trzuskawica S.A. (Poland)

Abstract The heterogeneous nature and widespread anthropogenic impacts on industrial water biotopes in the Trzuskawica S.A., pose challenges to biomonitoring of this habitat. Generally, the concentration of trace elements in the industrial water biotopes reflects the anthropogenic impacts. With X-ray fluorescence method (TXRF) in waters 17 elements:P,S,Cl,K,Ca,Ti,Cr, Mn,Fe,Ni,Cu,Zn,Br,Rb, Sr, Ba, Pb were revealed. High amounts of Ca, from 300 ppm to 198 ppm in May and from 999 ppm to 231 ppm in September 2015, was determined. A total of 36 diatoms were found in two reservoirs and drainage ditch, but only three taxa: Cymatopleura radiosa, Navicula upsaliensis and Nitzschia angustata were present in all 7 sampling sites. These species are known to be tolerant to organic pollution, eutrophication, and also characteristic for limestone waters. The results of CVA showed that dintoms in the water reservoir stocked with fish were distinguished by highest species richness. The relationships between diatoms and environmental variables confirm the positive correlation with the currently functioning industrial plant (despite the increased water temperature and large content of trace elements). Our results suggest that, though heterogeneity in both diatoms and selected elements in industrial waters, diatoms can be useful indicators of habitat conditions.