New observations on a rare endobiotic green alga, Stomatochroon lagerheimii, from a tropical area in China

Stomatochroon lagerheimii is a rare endobiotic green alga that lives in the stomatal chambers of the leaves from tropical vascular plants. The only report, to date, on this species was from Sumatra, Indonesia, by Palm in 1934. For this study, specimens were collected from a tropical rain forest inYunan, south west China, and each section of the thallus was measured using these Chinese specimens since the dimensions for each part were not given in Palm's original description. Using LM and SEM, this study has discovered further important characteristics about S. lagerheimii. Notably, that the external part of S. lagerheimii can be deep orange - red as well as deep purple, the sporangia wall is reticulate and the setae are the first structures to arise from the basal cell of a germling. The host plants, originally from Indonesia and China, are from the genus, Clerodendrum (Verbenaceae), which suggests that this alga is an endobiotic parasitic species that exhibits host specificity.Stomatochroon lagerheimii is a rare endobiotic green alga that lives in the stomatal chambers of the leaves from tropical vascular plants. The only report, to date, on this species was from Sumatra, Indonesia, by Palm in 1934. For this study, specimens were collected from a tropical rain forest inYunan, south west China, and each section of the thallus was measured using these Chinese specimens since the dimensions for each part were not given in Palm's original description. Using LM and SEM, this study has discovered further important characteristics about S. lagerheimii. Notably, that the external part of S. lagerheimii can be deep orange - red as well as deep purple, the sporangia wall is reticulate and the setae are the first structures to arise from the basal cell of a germling. The host plants, originally from Indonesia and China, are from the genus, Clerodendrum (Verbenaceae), which suggests that this alga is an endobiotic parasitic species that exhibits host specificity

Polulichloris henanensis gen. et sp nov (Trebouxiophyceae, Chlorophyta), a novel subaerial coccoid green alga

Coccoid green algae are abundant in subaerial habitats, but they are largely unexplored because of their morphological uniformity. Several new genus-level lineages have recently been described on the basis of molecular data. In this study, a coccoid green alga was isolated from surface soil in Zhoukou, Henan Province, China, and the cultured cells were described using light and electron microscopy. The ellipsoidal cell had smooth cell wall and parietal chloroplast with a pyrenoid surrounded by a starch envelope. Reproduction occurred by formation of 2-16 autospores. Molecular phylogenetic analyses based on the nuclear 18S rDNA gene and the chloroplast ribulose-bisphosphate carboxylase gene (rbcL) indicated that this coccoid green alga represents a new lineage of the Watanabea clade (Trebouxiophyceae, Chlorophyta). Here, we describe this organism as a new genus and species, Polulichloris henanensis, gen. et sp. nov

Improved Methodology for Identification of Cryptomonads: Combining Light Microscopy and PCR Amplification

Cryptomonads are unicellular, biflagellate algae. Generally, cryptomonad cells cannot be preserved well because of their fragile nature, and an improved methodology should be developed to identify cryptomonads from natural habitats. In this study, we tried using several cytological fixatives, including glutaraldehyde, formaldehyde, and their combinations to preserve field samples collected from various waters, and the currently used fixative, Lugol's solution was tested for comparison. Results showed that among the fixatives tested, glutaraldehyde preserved the samples best, and the optimal concentration of glutaraldehyde was 2%. The cell morphology was well preserved by glutaraldehyde. Cells kept their original color, volume, and shape, and important taxonomic features such as furrow/gullet complex, ejectosomes, as well as flagella could be observed clearly, whereas these organelles frequently disappeared in Lugol's solution preserved samples. The osmotic adjustments and buffers tested could not preserve cell density significantly higher. Statistical calculation showed the cell density in the samples preserved by 2% glutaraldehyde remained stable after 43 days of the fixation procedure. In addition, DNA was extracted from glutaraldehyde preserved samples by grinding with liquid nitrogen and the 18S rDNA sequence was amplified by PCR. The sequence was virtually identical to the reference sequence, and phylogenetic analyses showed very close relationship between it and sequences from the same organism. To sum up, the present study demonstrated that 2% unbuffered glutaraldehyde, without osmotic adjustments, can preserve cryptomonads cells for identification, in terms of both light microscopy and phylogenetic analyses based on DNA sequences.Cryptomonads are unicellular, biflagellate algae. Generally, cryptomonad cells cannot be preserved well because of their fragile nature, and an improved methodology should be developed to identify cryptomonads from natural habitats. In this study, we tried using several cytological fixatives, including glutaraldehyde, formaldehyde, and their combinations to preserve field samples collected from various waters, and the currently used fixative, Lugol's solution was tested for comparison. Results showed that among the fixatives tested, glutaraldehyde preserved the samples best, and the optimal concentration of glutaraldehyde was 2%. The cell morphology was well preserved by glutaraldehyde. Cells kept their original color, volume, and shape, and important taxonomic features such as furrow/gullet complex, ejectosomes, as well as flagella could be observed clearly, whereas these organelles frequently disappeared in Lugol's solution preserved samples. The osmotic adjustments and buffers tested could not preserve cell density significantly higher. Statistical calculation showed the cell density in the samples preserved by 2% glutaraldehyde remained stable after 43 days of the fixation procedure. In addition, DNA was extracted from glutaraldehyde preserved samples by grinding with liquid nitrogen and the 18S rDNA sequence was amplified by PCR. The sequence was virtually identical to the reference sequence, and phylogenetic analyses showed very close relationship between it and sequences from the same organism. To sum up, the present study demonstrated that 2% unbuffered glutaraldehyde, without osmotic adjustments, can preserve cryptomonads cells for identification, in terms of both light microscopy and phylogenetic analyses based on DNA sequences

Occurrence of true branches in Rhizoclonium (Cladophorales, Ulvophyceae) and the reinstatement of Rhizoclonium pachydermum Kjellman

The phylogenetic position of the freshwater green alga Rhizoclonium pachydermum ( Ulvophyceae: Cladophorales) was investigated using nuclear 18S rRNA gene and internal transcribed spacer 2 ( ITS2) sequences. This alga has been referred to as Cladophora pachyderma. Based on its morphology, it was formerly classified in the section Affines in the genus Cladophora. However, this classification was not supported by the current phylogenetic analyses, where Rhizoclonium pachydermum formed a well-supported clade with other Rhizoclonium species. We consider that Rhizoclonium possesses real branches and the most important criteria that characterize the genus are: long unbranched filaments only with rhizoid branches, or only branched at the basal region of the thallus; and cylindrical cells with few or limited numbers of nuclei.The phylogenetic position of the freshwater green alga Rhizoclonium pachydermum ( Ulvophyceae: Cladophorales) was investigated using nuclear 18S rRNA gene and internal transcribed spacer 2 ( ITS2) sequences. This alga has been referred to as Cladophora pachyderma. Based on its morphology, it was formerly classified in the section Affines in the genus Cladophora. However, this classification was not supported by the current phylogenetic analyses, where Rhizoclonium pachydermum formed a well-supported clade with other Rhizoclonium species. We consider that Rhizoclonium possesses real branches and the most important criteria that characterize the genus are: long unbranched filaments only with rhizoid branches, or only branched at the basal region of the thallus; and cylindrical cells with few or limited numbers of nuclei

Ulvella tongshanensis (Ulvellaceae, Chlorophyta), a new freshwater species from China, and an emended morphological circumscription of the genus Ulvella

A new freshwater species of Ulvella, Ulvella tongshanensis H. ZHU et G. LIU, is described from material collected from rocks under small waterfalls in Hubei Province, China. This unusual species differs from other species in the genus by the macroscopic and upright parenchymatous thalli, and by the particular habitat (most Ulvella species occur in marine environments). Phylogenetic analyses of plastid encoded rbcL and tufA, and nuclear 18S rDNA sequences, pointed towards the generic placement of Ulvella tongshanensis and also showed a close relationship with two other freshwater species, Ulvella bullata (Jao) H. ZHU et G. LIU, comb. nov. and Ulvella prasina (Jao) H. ZHU et G. LIU, comb. nov. The latter two were previously placed in the genus Jaoa and are characterized by disc-shaped to vesicular morphology. Our study once again shows that traditionally used morphological characters are poor indicators for phylogenetic relatedness in morphologically simple algae like the Ulvellaceae. Thus, the morphological circumscription of the genus Ulvella is here expanded to include: (1) thalli that are uniseriate in basal and apical parts, and parenchymatous in the middle portion with distinct differentiation of an unbranched dorsal side and a ventral side developing many short branches, and (2) epibiotic or epilithic, disc-shaped to vesicular thalli with a di- or tristromatic structure