- Volume 60, Issue 8, 2010

A Gram-negative, motile, oxidase- and catalase-positive and facultatively aerobic bacterium, designated S3-22T, was isolated from marine sediment of the Nella Fjord, Antarctica. Strain S3-22T reduced nitrate to nitrite and grew at pH 6.0–8.0, at 4–25 °C and with 0.5–5 % (w/v) NaCl. It contained Q-8 as the only respiratory quinone and summed feature 3 (C16 : 1 ω7c and/or iso-C15 : 0 2-OH), C16 : 0 and C18 : 1 ω7c as the major cellular fatty acids. The genomic DNA G+C content was 45.6 mol%. Phylogenetic analyses of 16S rRNA gene sequences showed that strain S3-22T was affiliated with the genus Neptunomonas, with 97.1 % sequence similarity to Neptunomonas japonica JAMM 0745T and 94.8 % to Neptunomonas naphthovorans NAG-2N-126T, the type strains of the only two recognized Neptunomonas species. DNA–DNA relatedness between strain S3-22T and N. japonica JCM 14595T was 20.4 %. Strain S3-22T could be distinguished from the type strains of Neptunomonas species by several phenotypic properties. Based on the evidence from our polyphasic study, strain S3-22T represents a novel Neptunomonas species, for which the name Neptunomonas antarctica sp. nov. is proposed. The type strain is S3-22T (=CCTCC AB 209086T =KACC 14056T).

Environmental DNA surveys have revealed a great deal of hidden diversity within the Cercozoa. An investigation into the biodiversity of heterotrophic flagellates in marine benthic habitats of British Columbia, Canada, demonstrated the presence of several undescribed taxa with morphological features that resemble the cercozoan genera Cryothecomonas and Protaspis. Nine novel species of marine interstitial cercozoans are described that are distributed into five genera, four of which are new. Phylogenetic analyses of small subunit rDNA sequences derived from two uncultured isolates of Protaspis obliqua and nine novel cercozoan species (within four novel genera) provided organismal anchors that helped establish the cellular identities of several different environmental sequence clades. These data, however, also showed that the rarity of distinctive morphological features in cryomonads, and other groups of cercozoans, makes the identification and systematics of the group very difficult. Therefore, a DNA barcoding approach was applied as a diagnostic tool for species delimitation that used a 618 bp region at the 5′ end of the SSU rDNA sequence. Nucleotide sequence analysis of this region showed high intergeneric sequence divergences of about 7 % and very low intraspecific sequence divergences of 0–0.5 %; phylogenetic analyses inferred from this barcoding region showed very similar tree topologies to those inferred from the full-length sequence of the gene. Overall, this study indicated that the 618 bp barcoding region of SSU rDNA sequences is a useful molecular signature for understanding the biodiversity and interrelationships of marine benthic cercozoans.

Three species of yeasts are taxonomically described for strains isolated from marine environments. Candida spencermartinsiae sp. nov. (type strain CBS 10894T =NRRL Y-48663T) and Candida taylorii sp. nov. (type strain CBS 8508T =NRRL Y-27213T) are anamorphic ascomycetous yeasts in a phylogenetic cluster of marine yeasts in the Debaryomyces/Lodderomyces clade of the Saccharomycetales. The two species were isolated from multiple locations among coral reefs and mangrove habitats. Pseudozyma abaconensis sp. nov. (type strain CBS 8380T =NRRL Y-17380T) is an anamorphic basidiomycete that is related to the smut fungi of the genus Ustilago in the Ustilaginales. P. abaconensis was collected from waters adjacent to a coral reef.