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The present study compared the stress response of two microalgal strains – Arthronema africanum (Cyanoprokaryota) and Coelastrella sp. BGV (Chlorophyta), after heavy metals’ treatment. Changes of algal growth, pigment and protein content were analyzed after adding Cu, Cd and Pb (50 µM and 100 µM) to the nutrition medium. It was found that Cd and Pb significantly inhibited growth and protein biosynthesis of microalgae, but the effect of Cu remained less pronounced. In both strains, a decrease of chlorophyll content was observed, while carotenoid content markedly increased, especially in Coelastrella sp. BGV biomass. The addition of 100 µM Cd and 100 µM Pb to the medium caused a strong enhancement of malondialdehyde in both microalgal strains, which corresponded to the significant increase of superoxide dismutase and catalase activity. The antioxidant enzymes appeared to be differently altered by heavy metals’ exposure. The activity of SOD in the Arthronema africanum cells was most strongly affected by Cd, in contrast to Coelastrella sp. BGV that was highly increased by 100 µM Pb. The application of 100 µM Cd and 100 µM Pb increased in a similar manner catalase activity in both microalgae. The strains that were studied showed a high absorption capacity for metal ions, especially for Pb, which was absorbed largely than Cd and Cu. For that reason, we assumed that both microalga and, in particular, Coelastrella sp. BGV, could be successfully used for treatment of contaminated water bodies.

The occurrence of three species belonging to the small coenobia forming green algae Desmodesmus and Didymocystis is reported from the northernmost part of Lake Tanganyika, East Africa. During a monitoring between September 2011 and October 2013 the highest number of cells of Desmodesmus bicellularis and Didymocystis comasii were observed in August and September, at the end of the dry season. On the other hand, the third taxon, Didymocystis cf. inermis, was only sporadically observed between September 2011 and March 2012. According to existing databases, it should be the first records from Africa of these three species. However, D. bicellularis (as Didymocystis bicellularis) was already reported in 2003 in phytoplankton samples of the pelagic zone from more southern located places in Lake Tanganyika.

This paper describes a new species from the Class Chlorophyceae, Mychonastes frigidus sp. nov., isolated from a cold-water mountain stream in the north of Russia (Subpolar Ural). The taxon is described using morphological and molecular methods. Mychonastes frigidus sp. nov. belongs to the group of species of the genus Mychonastes with spherical single cells. Comparison of ITS2 rDNA sequences and its secondary structures combined with the compensatory base changes approach confirms the separation between Mychonastes frigidus sp. nov and other species of the genus. Mychonastes frigidus sp. nov. represents a cryptic species that can only be reliably identified using molecular data.

The Pandanduri Dam has a function as a support for agricultural irrigation water and also supports community activities so that it will affect the quality of its waters. The quality of the water needs to be analyzed because it can affect the aquatic ecosystem. This study aims to determine the level of water pollution in the Pandanduri Dam based on the phytoplankton community from the Chlorophyta Division. This type of research is descriptive exploratory. Sampling was carried out at 5 stations that were haphazardly selected with ecological representativeness consideration. Phytoplankton data were analyzed using the abundance formula, Shannon-Wiener diversity index, PIELOU uniformity index, and Simpson dominance index. The phytoplankton from the Chlorophyta Division found in the Pandanduri Dam were 14 species that are Pediastrum duplex var. Gracillimum, Gonium sp. 1, Gonium sp. 2, Coelastrum reticulatum, Scenedesmus acuminatus, Cosmarium sp., Chlamydomonas nasuta, Chlamydomonas sp., Selenastrum capricornutum, Monoraphidium dybowskii, Monoraphidium contortum, Monoraphidium irregular, Westella botryoides, and Kirchneriella lunaris consisting of 4 orders (Sphaeropleales, Chlorococcales, Chlamydomonadales and Desmidiales) and 10 genera (Pediastrum, Coelastrum, Scenedesmus, Gonium, Cosmarium, Chlamydomonas, Selenastrum, Monoraphidium, Westella, and Kirchneriella). The species diversity index of 2.21 is classified as moderate diversity, the species uniformity index is 0.83 which indicates even species growth, and the species dominance index indicates that no species dominates with a value of 0.12. The level of water pollution in the Pandanduri Dam was found in the moderate pollution category (oligotrophic).

Lanceola sphaerica Vinogradov, 1970 Lanceola clausi var. sphaerica Vinogradov 1957: 196, fig. 6. Lanceola sphaerica Vinogradov, 1970: 383, 386���388, figs 1���2.��� Vinogradov et al. 1982 / 1996: 73���75 /84���86, fig. 20.���Zeidler 2009: 44���45, fig. 13.��� Zeidler 2019: 514. Material examined. Southern Ocean: immature female (USNM 1090248), Amundsen Sea, Cruise 11, station 930 [70��08���S 109��48���W], 1,391 m, 19 January 1964 (figured here). SE Pacific: immature female (USNM 1089971), off Chilean coast near Valdivia, Cruise 6, station 326 [38��19���S 74��34���W], 1,691���2,072 m, 25 November 1962. Type material. Lanceola sphaerica was first described as a variety of L. clausi from two damaged specimens, a mature female (8 mm) and a male (9 mm), both caught in the Kurile-Kamchatka region of the North-West Pacific. The female from Vityaz station 2076 [43��39���N 149��24���E], 4,200 ���7,800 m, 9 May 1953 and the male from Vityaz station 2208 [49��23���N 158��45���E], 0���6,500 m, 22 June 1953 (Vinogradov 1957). Later, Vinogradov (1970) established it as a full species with the availability of a well-preserved male (5.5 mm) from the same general area; Vityaz station 5626 [45��11���N 152��28���E], 3,000 ���4,000 m, 23���24 August 1966. All three specimens are in the Zoological Museum of the Moscow State University (Mb���1051, 1052, 1053). Description of immature female 4.5 mm (Fig. 3). Pereonites 1���4 inflated, almost spherical. Head without rostrum. Eyes very small, reniform, without crystalline cones. A1 slightly longer than head and first pereonite combined. A2 as long as A1 with two long setae terminally. G1; basis relatively slender, slightly shorter than remaining articles combined; carpus length 0.5 x basis, distal margin width about 1.3 x proximal margin of propodus; propodus conical-shaped, length about 2 x proximal width; dactylus length almost 0.5 x propodus. G2 much longer and slenderer than G1; basis length about 0.7 x remaining articles combined, about 2 x carpus length; propodus gradually tapering to narrow distal margin, length about 1.4 x carpus; dactylus inserted terminally to propodus, length about 0.4 x propodus. P3 and P4 similar in length and morphology; basis length slightly more than 2 x merus; merus with distinct antero-distal bulge, maximum width about 0.8 x length; carpus length 1.6 x merus for P3, 1.8 x merus for P4; propodus length 1.3 x carpus for P3, 1.1 x carpus for P4; dactylus length slightly more than 0.3 x propodus. P5���7 all with relatively long, slender articles and fully retractile, hooded dactyls but propodus not club-like distally. P5 slightly shorter than P4; basis length almost 2 x merus; carpus length 1.3 x merus, 0.8 x propodus; dactylus in relatively broad hollow. P6 length almost 1.3 x P5, slightly longer than first four pereonites combined; basis length about 2 x merus; merus with very slight postero-distal bulge; carpus length 1.5 x merus; propodus length about 1.4 x merus; dactylus strongly curved, pressed against anterior margin of propodus. P7 length 0.7 x P6; basis length 2.5 x merus; merus with slight postero-distal bulge; carpus length 1.2 x merus, about 0.6 x propodus. Urosome with relatively slender peduncles and rami. Rami of all uropoda more or less sub-equal in length, with slightly serrated margins. Peduncles and rami of U1 & U2 similar in length. Peduncle length of U3 slightly less than rami. Telson acute, apex rounded; length about 1.5 x width at base, reaching to about the middle of peduncle of U3. Remarks. Lanceola sphaerica is distinguished from all its congeners by a combination of several characters; i) the inflated pereon (especially in females); ii) the relatively long dactyls of P3���7 (especially P 3���4 in mature males); iii) the structure of P5 becoming sub-chelate in males; and iv) the relatively short telson. It is clearly most similar to the highly variable species, L. clausi, in the general habitus and the relative lengths of the pereopods but is readily distinguished by the slightly more inflated pereon and the relatively longer dactyls of P3���7. The female specimen described here is similar to L. clausi pirloti Shoemaker, 1945 in that the antennae are of similar length and the merus of P3���4 has a distinct antero-distal bulge, but differs from it in that the basis of the gnathopoda is slender; P6 is relatively longer and the uropoda are slenderer. In the long dactyls of P3 and P4, it resembles L. longidactyla Vinogradov, 1964 but in that species the dactyls are relatively much longer and P5 is not modified. It also resembles L. chelifera Vinogradov, 1970, especially in the modification of P5 but in that species the dactylus of P5 is not retractile or hooded and the structure of P3 and P4 is completely different. As noted by Vinogradov (1970), females of L. sphaerica differ from males in the following characters: i) P3 and P4 are more weakly armed and the dactyls are relatively shorter; ii) the articles of P5 are more linear, with less armature and the propodus is not robust and the dactylus is not as strong, not becoming sub-chelate. The specimen described here agrees with these characters and there are only very minor differences in the relative lengths of articles that can be determined from the limited information provided for the female by Vinogradov (1957, 1970). The sexual dimorphism exhibited in the morphology of P5 seems to become more prominent in mature males. Like L. clausi, L. sphaerica seems to occur in the colder waters of both Hemispheres. Distribution. Known only from the Kurile-Kamchatka region of the Pacific Ocean, the Amundsen Sea, Antarctica and the South-East Pacific, as detailed above. The latter is a new distribution record for L. sphaerica. Vinogradov (1970) records it as ���one of the most deeply-living hyperiids, being restricted to the abyssopelagic zone (including the trench waters) and does not rise above 3,000 m into the bathypelagic���, based on the specimens from the Kurile-Kamchatka region. It is recorded here from 1,391 m and 1,691 ���2,072 m., Published as part of Zeidler, Wolfgang, 2021, Redescription of two rare, deep-sea species of hyperiidean amphipod, Lanceola loveni antarctica Vinogradov, 1962 and L. sphaerica Vinogradov, 1970 (Crustacea: Amphipoda: Hyperiidea: Lanceolidae), pp. 106-114 in Zootaxa 5067 (1) on pages 111-113, DOI: 10.11646/zootaxa.5067.1.6, http://zenodo.org/record/5656569, {"references":["Vinogradov, M. E. (1970) New data on the amphipods Hyperiidea Physosomata of the northwest part of the Pacific. Trudy Instituta Okeanologii Akademiya Nauk SSSR, 86, 382 - 400. [in Russian; English translation: In: Bogorov, V. G. (Ed.), Fauna of the Kurile-Kamchatka Trench and its Environmen. Israel Program for Scientific Translations, Jerusalem, pp. 398 - 418 (1972)]","Vinogradov, M. E. (1957) Hyperiids (Amphipoda) of the Northwest Pacific Ocean. 1. Tribe Hyperiidea Physosomata. Trudy Instituta Okeanologii Akademiya Nauk SSSR, 20, 186 - 227. [in Russian; English translation: Marine Biology. Vol. 20. American Institute of Biological Sciences, Washington D. C., pp. 149 - 184 (1959)]","Vinogradov, M. E., Volkov, A. F. & Semenova, T. N. (1982) Amfipody-Giperiidy (Amphipoda: Hyperiidea) Mirovogo Okeanea. Akademiya Nauk SSSR, Opredeliteli po Faune SSSR, No. 132. Leningrad, 492 pp. [in Russian]","Vinogradov, M. E., Volkov, A. F. & Semenova, T. N. (1996) Hyperiid Amphipods (Amphipoda, Hyperiidea) of the World Oceans. Smithsonian Institution Libraries, D. Siegel-Causey, Scientific Editor, Washington D. C. and Oxonian Press Pvy. Ltd., New Delhi, 632 pp. [English translation from 1982 Russian original]","Zeidler, W. (2019) New and additional records of hyperiidean amphipods of the Infraorder Physosomata (Crustacea: Amphipoda: Hyperiidea) from the Antarctic Zone of the Southern Ocean. Zootaxa, 4576 (3), 510 - 520. https: // doi. org / 10.11646 / zootaxa. 4576.3.5","Shoemaker, C. R. (1945) The Amphipoda of the Bermuda Oceanographic Expeditions, 1929 - 1931. Zoologica, New York, 30 (4), 185 - 266. https: // doi. org / 10.5962 / p. 210854","Vinogradov, M. E. (1964) Hyperiidea Physosomata from the northern part of the Indian Ocean. Trudy Instituta Okeanologii Akademiya Nauk SSSR, 65, 107 - 151. [in Russian]"]}

We sampled the first mitogenomes from a novel lineage of the Chlorophyceae that is sister to Sphaeropleales. Although the Jenufa perforata (27,180 bp) and Jenufa minuta (41,488 bp) mitogeno...

Mitogenome evolution in the Chlorophyceae is characterized by the acquisition of a reduced-derived pattern by the Chlamydomonadales + Sphaeropleales clade. Because no mitogenomes are available for the sister clade Oedogoniales + Chaetophorales + Chaetopeltidales, it remains unclear whether the common ancestor of chlorophycean green algae harbored a reduced-derived or ancestral-type mitogenome. The 70,191 and 46,765-bp mitogenomes reported here for Bulbochaete rectangularis var. hiloensis (Oedogoniales) and Stigeoclonium helveticum (Chaetophorales), respectively, shed light on this question. Both contain the same set of 41 conserved genes, a repertoire lacking numerous protein-coding genes but featuring all 27 tRNA genes typically found in ancestral-type mitogenomes.

In 2013, UNESCO classified the ‘University of Coimbra – Alta and Sofia’ (Portugal) as World Heritage site. Some of the limestone monuments that compose the site, such as the Old Cathedral of Coimbra, show clear visual effects of biological colonization by cyanobacteria and microalgae. The aim of this study was to thoroughly characterize the structural diversity of the photoautotrophic community at this site, combining isolation and molecular identification with next-generation sequencing techniques. Culture-dependent approaches resulted on the identification of green microalgae belonging to Prasiolales, Chlorellales, Watanabea, Chlamydomonadales and Sphaeropleales clades, and cyanobacteria belonging to Nostocales and Synechococcales clades. Culture-independent methods using Illumina Platform resulted in the identification of 610 Operational Taxonomic Units (OTUs), revealing the presence of populations within phyla Chlorophyta, Cyanobacteria, Rhodophyta and Stramenopiles/Bacillariophyta. In addition, principal component analysis (PCA) and a network analysis were generated and successfully related the different populations to specific biodeterioration scenarios observed at this monument. The use of culture-dependent and -independent techniques together with PCA and network analysis allowed us to understand the distribution patterns of the photoautotrophic community among the different biofilms observed at this monument, as well as their ecological specifications. This study highlights that both cultivation and metagenomics methodologies should be employed synergistically in similar biodeterioration studies.

Reports of programmed cell death (PCD) across the taxonomic spectrum of photosynthetic unicellular organisms raise questions concerning its ecological and evolutionary roles. However, prior to ecological studies or evolutionary interpretations, it is essential to document phenotypic changes associated with PCD at the single-cell level, since death-related responses vary between taxa and within a single taxon depending on environmental stimuli. Here, we report responses to rapidly changing light, temperature and fluctuations in macronutrients in the model selenastracean green microalga Ankistrodesmus densus (Chlorophyta, Chlorophyceae, Sphaeropleales). We used stringent, but environmentally appropriate, conditions of prolonged darkness, nitrogen starvation (4 days), heat (1 h at 44°C) and cold shock (3 h at 2 ± 2°C). PCD phenotypes were examined by ultrastructural changes, phosphatidylserine (PS) externalization and DNA degradation. Flow cytometric Annexin V FITC analyses revealed that darkness and nitrogen-deprived cultures had significantly higher proportions of cells with PS externalization compared with controls (p < 0.05). Heat and cold treatments did not affect PS externalization (p = 0.44 and p = 0.99, respectively). Transmission electron microscopy (TEM) of light-deprived cells demonstrated, among other ultrastructural changes, marked cytoplasmic vacuolization suggesting a subtype of PCD known as vacuolar cell death. Nitrogen-starved cells had less vacuolization but presented more typical ultrastructural markers of PCD such as chromatin condensation and marginalization. In contrast, the more severe heat and cold shock treatments resulted in necrotic-like features. These findings suggest that prolonged darkness and nitrogen starvation induce PCD in a small (8.4 3.5 and 7.42 2.6%, respectively) but significant (p < 0.05) fraction of the A. densus population. Documenting these different death-related phenotypes depending on different environmental inducers is essential for interpreting ecological studies. Furthermore, our data support the hypothesis that autophagic/vacuolar cell death (VCD), which is central to organism homeostasis in plants (Streptophyta), occurs in Chlorophyta. VCD probably arose long before the evolution of multicellularity in plants. HIGHLIGHTSDarkness and nitrogen deprivation induce different programmed cell death markers in Ankistrodesmus densus;Plant vacuolar-like cell death occurs in Chlorophyta;There is crossover between the vacuolar and apoptosis-like death morphotypes. Darkness and nitrogen deprivation induce different programmed cell death markers in Ankistrodesmus densus; Plant vacuolar-like cell death occurs in Chlorophyta; There is crossover between the vacuolar and apoptosis-like death morphotypes.

Diverse algae possess the ability to recover from extreme desiccation without forming specialized resting structures. Green algal genera such as Tetradesmus (Sphaeropleales, Chlorophyceae) contain temperate terrestrial, desert, and aquatic species, providing an opportunity to compare physiological traits associated with the transition to land in closely related taxa. We subjected six species from distinct habitats to three dehydration treatments varying in relative humidity (RH 5%, 65%, 80%) followed by short- and long-term rehydration. We tested the capacity of the algae to recover from dehydration using the effective quantum yield of photosystem II as a proxy for physiological activity. The degree of recovery was dependent both on the habitat of origin and the dehydration scenario, with terrestrial, but not aquatic, species recovering from dehydration. Distinct strains of each species responded similarly to dehydration and rehydration, with the exception of one aquatic strain that recovered from the mildest dehydration treatment. Cell ultrastructure was uniformly maintained in both aquatic and desert species during dehydration and rehydration, but staining with an amphiphilic styryl dye indicated damage to the plasma membrane from osmotically induced water loss in the aquatic species. These analyses demonstrate that terrestrial Tetradesmus possess a vegetative desiccation tolerance phenotype, making these species ideal for comparative omics studies.

Diverse algae possess vegetative desiccation tolerance, the ability to recover from extreme desiccation without forming specialized resting structures. Green algal genera such as Tetradesmus (Sphaeropleales, Chlorophyceae) contain both terrestrial and aquatic species, providing an opportunity to compare physiological traits associated with the transition to land in closely related taxa. We subjected six species from aquatic and terrestrial habitats to three desiccation treatments varying in final relative humidity followed by short- and mid-term rehydration. We tested the capacity of the algae to recover from desiccation using the effective quantum yield of photosystem II as a proxy for physiological activity. The degree of recovery was dependent both on the habitat of origin and the desiccation scenario, with terrestrial, but not aquatic species, recovering from desiccation. Distinct strains of each species responded similarly to desiccation and rehydration, with the exception of one aquatic strain that recovered from the mildest desiccation. Cell ultrastructure was uniformly maintained in both aquatic and desert species during dehydration and rehydration, but staining with an amphiphilic styryl dye indicated desiccation-induced damage to the plasma membrane in the aquatic species. These analyses demonstrate that terrestrial Tetradesmus possess the vegetative desiccation tolerance phenotype, making these species ideal for comparative omics studies.

Coelastrum proboscideum Bohlin, 1896 (Sphaeropleales, Scenedesmaceae, Chlorophyta) is a coenobial species with cosmopolitan distribution in diverse freshwater habitats. Coelastrum spp. are widely tested for biotechnological applications such as carotenoid and lipid production, and in bioremediation of wastewater. Here, we report the draft genome of C. proboscideum var. dilatatum strain SAG 217-2. The final assembly comprised 125,935,854 bp with over 8357 scaffolds. The whole-genome data is publicly available in the Nucleotide Sequence Archive (CNSA) of China National GeneBank (CNGB) (https://db.cngb.org/cnsa/) under the accession number CNA0014153.

This study identified the genus Coelastrella Chodat, 1922 which was isolated from a sediment sample taken from the Tigris river in Baghdad Governorate, Iraq. The alga was isolated and cultured in modified Chu 10 media and the morphological features of the isolated algae were observed in light microscopy (LM); it showed some characteristic features of this genus, such as its ellipsoidal or lemon- shaped cells, a visible pyrenoid and the chloroplast parietal. To ensure correct identification of the isolated alga, a molecular analysis using 18S rRNA gene and DNA sequencing revealed a match with C. terrestris (Reisigl) Hedewald & N. Hanagata 2002. This species is a new record in Iraq, and has been registered in NCBI under the accession number MH179121.

The family Radiococcaceae sensu lato, defined as colonial autospore-producing mucilaginous coccoid green algae, is widespread in terrestrial and freshwater habitats. Three species of Radiococcaceae sensu lato, including two Radiococcus species and one Planktosphaeria species, were described from China by light and electron microscopy. A new species of Planktosphaeria, Planktosphaeria hubeiensis sp. nov. was erected based on morphological comparisons and genetic analyses. Our phylogenetic analyses indicated that Radiococcaceae sensu lato is polyphyletic, and separated into three lineages. The Radiococcus species did not cluster into a monophyletic group in phylogenetic analyses; therefore the taxonomy of the genus Radiococcus should be revised in the future.

Conventional identification of three coccoid green algae isolates was attempted to characterize the studied algae morphologically under compound microscope, which demonstrated confusional phenomenal convergence; all were classified microscopically as the green alga Chlorella vulgaris Beijerinck, 1890. Phylogenetic studies were conducted to settle the argument about the phenotype by studying the genotype. Genotype the promising field in advance classification by using 18S rRNA and compared to GenBank database using to search the related sequences. The determined sequences showed high a similarity to the strains registered in GenBank. Phylogenetic tree of ITS within 18S RNA were analyzed: the phylogram separated into two clusters, the first cluster included C1-ITS-Iraq and C2-ITS-Iraq and put with Coelastrella Chodat, 1922 which was well supported in bootstrap tests (86-100%), while the second cluster included C3-ITS-Iraq and put with C. sorokiniana Shihira and Krauss, 1965, which have bootstrap value 100% with the mentioned species. however, in this study, the green alga Colestrella was identified as new record genus in Iraqi freshwater belonged to the order Sphaeropleales.

PREMISE OF THE STUDY Phylogenomic analyses across the green algae are resolving relationships at the class, order, and family levels and highlighting dynamic patterns of evolution in organellar genomes. Here we present a within-family phylogenomic study to resolve genera and species relationships in the family Hydrodictyaceae (Chlorophyceae), for which poor resolution in previous phylogenetic studies, along with divergent morphological traits, have precluded taxonomic revisions. METHODS Complete plastome sequences and mitochondrial protein-coding gene sequences were acquired from representatives of the Hydrodictyaceae using next-generation sequencing methods. Plastomes were characterized, and gene order and content were compared with plastomes spanning the Sphaeropleales. Single-gene and concatenated-gene phylogenetic analyses of plastid and mitochondrial genes were performed. KEY RESULTS The Hydrodictyaceae contain the largest sphaeroplealean plastomes thus far fully sequenced. Conservation of plastome gene order within Hydrodictyaceae is striking compared with more dynamic patterns revealed across Sphaeropleales. Phylogenetic analyses resolve Hydrodictyon sister to a monophyletic Pediastrum, though the morphologically distinct P. angulosum and P. duplex continue to be polyphyletic. Analyses of plastid data supported the neochloridacean genus Chlorotetraedron as sister to Hydrodictyaceae, while conflicting signal was found in the mitochondrial data. CONCLUSIONS A phylogenomic approach resolved within-family relationships not obtainable with previous phylogenetic analyses. Denser taxon sampling across Sphaeropleales is necessary to capture patterns in plastome evolution, and further taxa and studies are needed to fully resolve the sister lineage to Hydrodictyaceae and polyphyly of Pediastrum angulosum and P. duplex.

The revision of the serie Desmodesmus, based on light microscopy, TEM, SEM and ITS2r DNA, allowed us to distinguish among the taxa Desmodesmus communis var. communis, var. polisicus, D. curvatocornis, D. rectangularis comb. nov., D. pseudocommunis n. sp. var. texanus n. var. and f. verrucosus n. f., D. protuberans, D. protuberans var. communoides var. nov., D. pseudoprotuberans n. sp., D. schmidtii n. sp. Keys were given for light microscopy, electron microscopy and ITS2r DNA.

Background Terrestrial, freshwater and marine green algae constitute the large and morphologically diverse phylum of Chlorophyta, which gave rise to the core chlorophytes. Chlorophyta are abundant and diverse in freshwater environments where sometimes they form nuisance blooms under eutrophication conditions. The phylogenetic relationships among core chlorophyte clades (Chlorodendrophyceae, Ulvophyceae, Trebouxiophyceae and Chlorophyceae), are of particular interest as it is a species-rich phylum with ecological importance worldwide, but are still poorly understood. In the Mediterranean ecoregion, data on molecular characterization of eukaryotic microalgae strains are limited and current knowledge is based on ecological studies of natural populations. In the present study we report the isolation and characterization of 11 green microalgae strains from Greece contributing more information for the taxonomy of Chlorophyta. The study combined morphological and molecular data. Results Phylogenetic analysis based on 18S rRNA, internal transcribed spacer (ITS) region and the large subunit of the ribulose-bisphosphate carboxylase (rbcL) gene revealed eight taxa. Eleven green algae strains were classified in four orders (Sphaeropleales, Chlorellales, Chlamydomonadales and Chaetophorales) and were represented by four genera; one strain was not assigned to any genus. Most strains (six) were classified to the genus Desmodesmus, two strains to genus Chlorella, one to genus Spongiosarcinopsis and one filamentous strain to genus Uronema. One strain is placed in a separate independent branch within the Chlamydomonadales and deserves further research. Conclusions Our study reports, for the first time, the presence of Uronema in an aquatic environment up to 40 °C and reveals new diversity within the Chlamydomonadales. The results from the ITS region and the rbcL gene corroborated those obtained from 18S rRNA without providing further information or resolving the phylogenetic relationships within certain genera, due to the limited number of ITS and rbcL sequences available. The comparison of molecular and morphological data showed that they were congruent. Cosmopolitan genera with high worldwide distribution inhabit Greek freshwaters.

Hariotina reticulata P. A. Dangeard 1889 (Sphaeropleales, Chlorophyta) is a common member of the summer phytoplankton of meso- to highly eutrophic water bodies with a worldwide distribution. Here, we report the draft whole-genome shotgun sequencing of H. reticulata strain SAG 8.81. The final assembly comprises 107,596,510bp with over 15,219 scaffolds (>100bp). This whole-genome project is publicly available in the CNSA (https://db.cngb.org/cnsa/) of CNGBdb under the accession number CNP0000705.

Mitochondria of diverse eukaryotes have evolved various departures from the standard genetic code, but the breadth of possible modifications and their phylogenetic distribution are known only incompletely. Furthermore, it is possible that some codon reassignments in previously sequenced mitogenomes have been missed, resulting in inaccurate protein sequences in databases. Here we show, considering the distribution of codons at conserved amino acid positions in mitogenome-encoded proteins, that mitochondria of the green algal order Sphaeropleales exhibit a diversity of codon reassignments, including previously missed ones and some that are unprecedented in any translation system examined so far, necessitating redefinition of existing translation tables and creating at least seven new ones. We resolve a previous controversy concerning the meaning the UAG codon in Hydrodictyaceae, which beyond any doubt encodes alanine. We further demonstrate that AGG, sometimes together with AGA, encodes alanine instead of arginine in diverse sphaeroplealeans. Further newly detected changes include Arg-to-Met reassignment of the AGG codon and Arg-to-Leu reassignment of the CGG codon in particular species. Analysis of tRNAs specified by sphaeroplealean mitogenomes provides direct support for and molecular underpinning of the proposed reassignments. Furthermore, we point to unique mutations in the mitochondrial release factor mtRF1a that correlate with changes in the use of termination codons in Sphaeropleales, including the two independent stop-to-sense UAG reassignments, the reintroduction of UGA in some Scenedesmaceae, and the sense-to-stop reassignment of UCA widespread in the group. Codon disappearance seems to be the main drive of the dynamic evolution of the mitochondrial genetic code in Sphaeropleales.

Mitochondria of diverse eukaryotes have evolved various departures from the standard genetic code, but the breadth of possible modifications and their phylogenetic distribution are known only incompletely. Furthermore, it is possible that some codon reassignments in previously sequenced mitogenomes have been missed, resulting in inaccurate protein sequences in databases. Here we show, considering the distribution of codons at conserved amino acid positions in mitogenome-encoded proteins, that mitochondria of the green algal order Sphaeropleales exhibit a diversity of codon reassignments, including previously missed ones and some that are unprecedented in any translation system examined so far, necessitating redefinition of existing translation tables and creating at least seven new ones. We resolve a previous controversy concerning the meaning the UAG codon in Hydrodictyaceae, which beyond any doubt encodes alanine. We further demonstrate that AGG, sometimes together with AGA, encodes alanine instead of arginine in diverse sphaeroplealeans. Further newly detected changes include Arg-to-Met reassignment of the AGG codon and Arg-to-Leu reassignment of the CGG codon in particular species. Analysis of tRNAs specified by sphaeroplealean mitogenomes provides direct support for and molecular underpinning of the proposed reassignments. Furthermore, we point to unique mutations in the mitochondrial release factor mtRF1a that correlate with changes in the use of termination codons in Sphaeropleales, including the two independent stop-to-sense UAG reassignments, the reintroduction of UGA in some Scenedesmaceae, and the sense-to-stop reassignment of UCA widespread in the group. Codon disappearance seems to be the main drive of the dynamic evolution of the mitochondrial genetic code in Sphaeropleales.

Lanceola loveni grossipes Shoemaker (Fig. 1C, D) Lanceola loveni grossipes Shoemaker, 1945: 209, fig. 16 g, h. Vinogradov 1957: 191; 1960a: 206. Vinogradov et al. 1982: 63–64, fig. 12. Type material. Shoemaker (1945) described this variety from eight specimens collected near Bermuda, at depths between 600 and 1000 fathoms. He states that “the length of the type female is 29 mm ”. The USNM has three female specimens, the type (109450) and two paratypes (109451 & 2). The whereabouts of the other five specimens is unknown. Material examined. Types. Holotype female (USNM 109450) and two paratype females (USNM 109451 & 2) from the North Atlantic, near Bermuda [32º12’N 52º36’W]; William Beebe Oceanographic Expedition, col. 7 Sept. 1931, 22 Jun. 1929 & 30 Jun. 1930 respectively: in spirit. Other material examined. Female 25 mm, semi-mature (SAMA C6252), N. E. Pacific, off Alexander Archipelago, British Columbia [53º59’N 138º46.12’W]; ex M. Galbraith, 250– 150m, 26 Sept. 2001. Diagnosis. Like typical form except for the following. Length of sexually mature females 27–30 mm. Pereopod 6 is relatively longer with propodus expanded distally into rounded club-shape, housing retractile dactylus. Pereopod 7 is slightly shorter than half-length P6. Remarks. Described as a mere variety of L. loveni by Shoemaker (1945) it was elevated to sub-specific rank by Vinogradov et al. (1982) and according to them the features characteristic of L. loveni grossipes are only exhibited by sexually mature females. Distribution. This subspecies has been recorded from the North Atlantic, near Bermuda [32º12’N 52º36’W] by Shoemaker (1945); the North–west Pacific, S.E. of Japan [30º52’N 153º16’E & 30º53’N 153º09’E] by Vinogradov (1957 & 1960a) and N.E. of Marshall Is [16º08’N 173º10’E] by Vinogradov (1960a). The SAMA specimen (Fig. 1) is the first record from the North-east Pacific., Published as part of Zeidler, Wolfgang, 2009, A review of the hyperiidean amphipod superfamily Lanceoloidea Bowman & Gruner, 1973 (Crustacea: Amphipoda: Hyperiidea), pp. 1-117 in Zootaxa 2000 on page 16, {"references":["Shoemaker, C. R. (1945) The Amphipoda of the Bermuda Oceanographic Expeditions, 1929 - 1931. Zoologica, New York, 30, 185 - 266.","Vinogradov, M. E. (1957) Hyperiids (Amphipoda) of the Northwest Pacific Ocean. 1. Tribe Hyperiidea Physosomata. Trudy Instituta Okeanologii Akademiya Nauk SSSR 20: 186 - 227. [In Russian]. English translation by American Institute of Biological Sciences, Washington D. C., 1959, Marine Biology, 149 - 184.","Vinogradov, M. E. (1960 a) Hyperiidea Physosomata of the Tropical Pacific Ocean. Trudy Instituta Okeanologii Akademiya Nauk SSSR 41, 198 - 247. [In Russian].","Vinogradov, M. E., Volkov, A. F. & Semenova, T. N. (1982) Amfipody-Giperiidy (Amphipoda: Hyperiidea) Mirovogo Okeanea. Akademiya Nauk SSSR, Opredeliteli po Faune SSSR No. 132. Leningrad, 492 pp. [In Russian]. English translation, 1996, Smithsonian Institution Libraries, Washington D. C., D. Siegel-Causey, Scientific Editor."]}

Genetic code deviations involving stop codons have been previously reported in mitochondrial genomes of several green plants (Viridiplantae), most notably chlorophyte algae (Chlorophyta). However, as changes in codon recognition from one amino acid to another are more difficult to infer, such changes might have gone unnoticed in particular lineages with high evolutionary rates that are otherwise prone to codon reassignments. To gain further insight into the evolution of the mitochondrial genetic code in green plants, we have conducted an in-depth study across mtDNAs from 51 green plants (32 chlorophytes and 19 streptophytes). Besides confirming known stop-to-sense reassignments, our study documents the first cases of sense-to-sense codon reassignments in Chlorophyta mtDNAs. In several Sphaeropleales, we report the decoding of AGG codons (normally arginine) as alanine, by tRNA(CCU) of various origins that carry the recognition signature for alanine tRNA synthetase. In Chromochloris, we identify tRNA variants decoding AGG as methionine and the synonymous codon CGG as leucine. Finally, we find strong evidence supporting the decoding of AUA codons (normally isoleucine) as methionine in Pycnococcus. Our results rely on a recently developed conceptual framework (CoreTracker) that predicts codon reassignments based on the disparity between DNA sequence (codons) and the derived protein sequence. These predictions are then validated by an evaluation of tRNA phylogeny, to identify the evolution of new tRNAs via gene duplication and loss, and structural modifications that lead to the assignment of new tRNA identities and a change in the genetic code.

Desmodesmus costato-granulatus (Skuja) Hegewald 2000 (Sphaeropleales, Chlorophyta) is a small, spineless green alga that is abundant in the freshwater phytoplankton of oligo- to eutrophic waters worldwide. It has a high lipid content and is considered for sustainable production of diverse compounds, including biofuels. Here, we report the draft whole-genome shotgun sequencing of D. costato-granulatus strain SAG 18.81. The final assembly comprises 48,879,637 bp with over 4,141 scaffolds. This whole-genome project is publicly available in the CNSA ( https://db.cngb.org/cnsa/ ) of CNGBdb under the accession number CNP0000701.

This study examined wall ultrastructure variability in the microscopic green alga Pediastrum s.l. Its value as a diagnostic character is discussed. Field and cultured material of 21 taxa were compared using light and scanning electron microscopy. Nine ultrastructural elements occurring on the surface of Pediastrum are documented with LM and SEM micrographs. The highest number of taxa showed reticulate ornamentation composed of a trigonal mesh and granules situated on its corners. The paper considers the use of wall ultrastructure to reconcile traditional and modern taxonomical systems with regard to Pediastrum varieties, and addresses the phylogenetic relationships between strains representing different varieties.

The chloroplast genomes of green algae are highly variable in their architecture. In this article we summarize gene content across newly obtained and published chloroplast genomes in Chlorophyceae, including new data from nine of species in Sphaeropleales (Chlorophyceae, Chlorophyta). We present genome architecture information, including genome synteny analysis across two groups of species. Also, we provide a phylogenetic tree obtained from analysis of gene order data for species in Chlorophyceae with fully sequenced chloroplast genomes. Further analyses and interpretation of the data can be found in “Chloroplast phylogenomic data from the green algal order Sphaeropleales (Chlorophyceae, Chlorophyta) reveal complex patterns of sequence evolution” (Fučíková et al., In review) [1].

Chloroplast sequence data are widely used to infer phylogenies of plants and algae. With the increasing availability of complete chloroplast genome sequences, the opportunity arises to resolve ancient divergences that were heretofore problematic. On the flip side, properly analyzing large multi-gene data sets can be a major challenge, as these data may be riddled with systematic biases and conflicting signals. Our study contributes new data from nine complete and four fragmentary chloroplast genome sequences across the green algal order Sphaeropleales. Our phylogenetic analyses of a 56-gene data set show that analyzing these data on a nucleotide level yields a well-supported phylogeny - yet one that is quite different from a corresponding amino acid analysis. We offer some possible explanations for this conflict through a range of analyses of modified data sets. In addition, we characterize the newly sequenced genomes in terms of their structure and content, thereby further contributing to the knowledge of chloroplast genome evolution.

Background Chlorophyceae is one of three most species-rich green algal classes and also the only class in core Chlorophyta whose monophyly remains uncontested as gene and taxon sampling improves. However, some key relationships within Chlorophyceae are less clear-cut and warrant further investigation. The present study combined genome-scale chloroplast data and rich sampling in an attempt to resolve the ordinal classification in Chlorophyceae. The traditional division into Sphaeropleales and Volvocales (SV), and a clade containing Oedogoniales, Chaetopeltidales, and Chaetophorales (OCC) was of particular interest with the addition of deeply branching members of these groups, as well as the placement of several incertae sedis taxa. Methods We sequenced 18 chloroplast genomes across Chlorophyceae to compile a data set of 58 protein-coding genes of a total of 68 chlorophycean taxa. We analyzed the concatenated nucleotide and amino acid datasets in the Bayesian and Maximum Likelihood frameworks, supplemented by analyses to examine potential discordant signal among genes. We also examined gene presence and absence data across Chlorophyceae. Results Concatenated analyses yielded at least two well-supported phylogenies: nucleotide data supported the traditional classification with the inclusion of the enigmatic Treubarinia into Sphaeropleales sensu lato. However, amino acid data yielded equally strong support for Sphaeropleaceae as sister to Volvocales, with the rest of the taxa traditionally classified in Sphaeropleales in a separate clade, and Treubarinia as sister to all of the above. Single-gene and other supplementary analyses indicated that the data have low phylogenetic signal at these critical nodes. Major clades were supported by genomic structural features such as gene losses and trans-spliced intron insertions in the plastome. Discussion While the sequence and gene order data support the deep split between the SV and OCC lineages, multiple phylogenetic hypotheses are possible for Sphaeropleales s.l. Given this uncertainty as well as the higher-taxonomic disorder seen in other algal groups, dwelling on well-defined, strongly supported Linnaean orders is not currently practical in Chlorophyceae and a less formal clade system may be more useful in the foreseeable future. For example, we identify two strongly and unequivocally supported clades: Treubarinia and Scenedesminia, as well as other smaller groups that could serve a practical purpose as named clades. This system does not preclude future establishment of new orders, or emendment of the current ordinal classification if new data support such conclusions.

The Sphaeropleales are a dominant group of green algae, which contain species important to freshwater ecosystems and those that have potential applied usages. In particular, Raphidocelis subcapitata is widely used worldwide for bioassays in toxicological risk assessments. However, there are few comparative genome analyses of the Sphaeropleales. To reveal genome evolution in the Sphaeropleales based on well-resolved phylogenetic relationships, nuclear, mitochondrial, and plastid genomes were sequenced in this study. The plastid genome provides insights into the phylogenetic relationships of R. subcapitata, which is located in the most basal lineage of the four species in the family Selenastraceae. The mitochondrial genome shows dynamic evolutionary histories with intron expansion in the Selenastraceae. The 51.2 Mbp nuclear genome of R. subcapitata, encoding 13,383 protein-coding genes, is more compact than the genome of its closely related oil-rich species, Monoraphidium neglectum (Selenastraceae), Tetradesmus obliquus (Scenedesmaceae), and Chromochloris zofingiensis (Chromochloridaceae); however, the four species share most of their genes. The Sphaeropleales possess a large number of genes for glycerolipid metabolism and sugar assimilation, which suggests that this order is capable of both heterotrophic and mixotrophic lifestyles in nature. Comparison of transporter genes suggests that the Sphaeropleales can adapt to different natural environmental conditions, such as salinity and low metal concentrations.

Background Comparative studies of chloroplast genomes (plastomes) across the Chlorophyceae are revealing dynamic patterns of size variation, gene content, and genome rearrangements. Phylogenomic analyses are improving resolution of relationships, and uncovering novel lineages as new plastomes continue to be characterized. To gain further insight into the evolution of the chlorophyte plastome and increase the number of representative plastomes for the Sphaeropleales, this study presents two fully sequenced plastomes from the green algal family Hydrodictyaceae (Sphaeropleales, Chlorophyceae), one from Hydrodictyon reticulatum and the other from Pediastrum duplex. Methods Genomic DNA from Hydrodictyon reticulatum and Pediastrum duplex was subjected to Illumina paired-end sequencing and the complete plastomes were assembled for each. Plastome size and gene content were characterized and compared with other plastomes from the Sphaeropleales. Homology searches using BLASTX were used to characterize introns and open reading frames (orfs) ≥ 300 bp. A phylogenetic analysis of gene order across the Sphaeropleales was performed. Results The plastome of Hydrodictyon reticulatum is 225,641 bp and Pediastrum duplex is 232,554 bp. The plastome structure and gene order of H. reticulatum and P. duplex are more similar to each other than to other members of the Sphaeropleales. Numerous unique open reading frames are found in both plastomes and the plastome of P. duplex contains putative viral protein genes, not found in other Sphaeropleales plastomes. Gene order analyses support the monophyly of the Hydrodictyaceae and their sister relationship to the Neochloridaceae. Discussion The complete plastomes of Hydrodictyon reticulatum and Pediastrum duplex, representing the largest of the Sphaeropleales sequenced thus far, once again highlight the variability in size, architecture, gene order and content across the Chlorophyceae. Novel intron insertion sites and unique orfs indicate recent, independent invasions into each plastome, a hypothesis testable with an expanded plastome investigation within the Hydrodictyaceae.

The phylogeny of the family Selenastraceae was investigated by light microscopy, 18S rDNA, rbcL and ITS-2 analyses. Various morphological features traditionally used for species and genera identification were investigated. All selenastracean strains studied have naked pyrenoids within the chloroplast, except the genus Chlorolobion, which presented starch envelope. The molecular analyses showed that no morphological criterion considered so far is significant for the systematics of the Selenastraceae, but a set of features may be suitable to identify the genera Ankistrodesmus and Chlorolobion. Phylogenetic analyses showed the genera Monoraphidium, Kirchneriella and Selenastrum were not monophyletic and not distinguishable as separate genera. The polyphyly of the genus Selenastrum led to the description of two new genera, Curvastrum gen. nov and Messastrum gen. nov.

The majority of our knowledge about mitochondrial genomes of Viridiplantae comes from land plants, but much less is known about their green algal relatives. In the green algal order Sphaeropleales (Chlorophyta), only one representative mitochondrial genome is currently available-that of Acutodesmus obliquus. Our study adds nine completely sequenced and three partially sequenced mitochondrial genomes spanning the phylogenetic diversity of Sphaeropleales. We show not only a size range of 25-53 kb and variation in intron content (0-11) and gene order but also conservation of 13 core respiratory genes and fragmented ribosomal RNA genes. We also report an unusual case of gene arrangement convergence in Neochloris aquatica, where the two rns fragments were secondarily placed in close proximity. Finally, we report the unprecedented usage of UCG as stop codon in Pseudomuriella schumacherensis. In addition, phylogenetic analyses of the mitochondrial protein-coding genes yield a fully resolved, well-supported phylogeny, showing promise for addressing systematic challenges in green algae.

In the present paper five species of Sorastrum Kutzing including a new species, Sorastrum philiposianum have been described from Bankura and Purulia districts of West Bengal, India. Amongst these species S. indicum Bernard and S. hathoris (Cohn) Schmidle are being reported for the first time from India. Moreover, S. americanum (Bohlin) Schmidle is an addition to West Bengal algae. All the specimens have been collected from desmids habitats of West Bengal having a low pH (5.0-6.5) and those were growing lodged on submerged portions of the aquatic weeds like Ceratophyllum demersum L., Hydrilla verticillata (L.f.) C. Presl and Ipomoea aquatica Forssk. DOI: http://dx.doi.org/10.3329/bjpt.v20i2.17399 Bangladesh J. Plant Taxon. 20(2): 243-249, 2013

Five green algal taxa rarely occurring in the world were found in subalpine lakes of the High Tatra Mountains in Poland. These are Actinastrum gracillimum G.M. Sm. var. elongatum (G.M. Sm.) Fott, Monoraphidium tatrae (Hindák) Hindák, Pediastrum braunii Wartm. in Wartm. et Schenk, Scotiella tuberculata Bourr. var. tuberculata and Thelesphaera olivacea (Beck-Mannag.) Fott. The taxa are described and illustrated with light micrographs and drawings. A review of their distribution in the world is presented.

The Chlorophyceae (sensu Mattox and Stewart) is a morphologically diverse class of the Chlorophyta displaying biflagellate and quadriflagellate motile cells with varying configurations of the flagellar apparatus. Phylogenetic analyses of 18S rDNA data and combined 18S and 26S rDNA data from a broad range of chlorophycean taxa uncovered five major monophyletic groups (Chlamydomonadales, Sphaeropleales, Oedogoniales, Chaetophorales, and Chaetopeltidales) but could not resolve their branching order. To gain insight into the interrelationships of these groups, we analyzed multiple genes encoded by the chloroplast genomes of Chlamydomonas reinhardtii P. A. Dang. and Chlamydomonas moewusii Gerloff (Chlamydomonadales), Scenedesmus obliquus (Turpin) Kutz. (Sphaeropleales), Oedogonium cardiacum Wittr. (Oedogoniales), Stigeoclonium helveticum Vischer (Chaetophorales), and Floydiella terrestris (Groover et Hofstetter) Friedl et O'Kelly (Chaetopeltidales). The C. moewusii, Oedogonium, and Floydiella chloroplast DNAs were partly sequenced using a random strategy. Trees were reconstructed from nucleotide and amino acid data sets derived from 44 protein-coding genes of 11 chlorophytes and nine streptophytes as well as from 57 protein-coding genes of the six chlorophycean taxa. All best trees identified two robustly supported major lineages within the Chlorophyceae: a clade uniting the Chlamydomonadales and Sphaeropleales, and a clade uniting the Oedogoniales, Chaetophorales, and Chaetopeltidales (OCC clade). This dichotomy is independently supported by molecular signatures in chloroplast genes, such as insertions/deletions and the distribution of trans-spliced group II introns. Within the OCC clade, the sister relationship observed for the Chaetophorales and Chaetopeltidales is also strengthened by independent data. Character state reconstruction of basal body orientation allowed us to refine hypotheses regarding the evolution of the flagellar apparatus.

A phylogenetic analysis of 26S and internal transcribed spacer–2 ribosomal DNA (rDNA) data from members of the freshwater green algal family Hydrodictyaceae, including multiple taxa from both culture collections and new isolates, sets the stage to explore morphological variation and patterns of colony-form evolution within the family. These analyses particularly focus on Pediastrum boryanum, P. tetras, P. duplex, Hydrodictyon and Sorastrum. The genera Hydrodictyon and Sorastrum are derived from within Pediastrum in the individual and combined analyses, indicating a pattern of colony-form evolution within the family from two-dimensionality to three-dimensionality. In some cases the gene topologies reveal discrepancies in the morphological characters used to delimit species, varieties and forms within Pediastrum. Some isolates, such as those of H. reticulatum, exhibited little or no genetic variation between different geographic localities. Additional data and taxa are needed to better resolve and ...

The complete mitochondrial genome of the green algae Hariotina sp. F30 was obtained in this study using Illumina sequencing data. It is 51 915 bp in length with 36.23% GC content. The genome contains 13 protein-coding genes, 23 tRNA genes and six rRNA genes, all of which are encoded on the heavy strand. AUG is a universal initiation codon among 13 protein-coding genes. UCA is a universal termination codon for most protein-coding gens except UAA in cox1 and cob genes and UGA in nad6 gene. CUU anticodon for tRNA-Lys was detected for the first time in Sphaeropleales.

The complete 18S rRNA gene sequences of four Sphaeroplea C.A. Agardh strains (Sphaeropleales, Sphaeropleaceae), two Atractomorpha Hoffman strains (Sphaeropleales, Sphaeropleaceae) and two Ankyra Fott strains (Chlorococcales, Characiaceae) were determined and subjected to phylogenetic analyses. The analyses indicated that all these taxa belong to a monophyletic lineage (Sphaeropleaceae) and are related to a group of chlorophycean algae comprising autosporic taxa and taxa that reproduce by zoospores which are characterized by directly opposed basal bodies. The taxonomic assignment of the Sphaeropleaceae as a family within the Sphaeropleales (Chlorophyta, Chlorophyceae) is discussed.