Phycological Research 

About: Phycological Research is an academic journal published by Wiley-Blackwell. The journal publishes majorly in the area(s): Population & Biology. It has an ISSN identifier of 1322-0829. Over the lifetime, 993 publications have been published receiving 17704 citations.

Amino acid composition, protein content and calculation of nitrogen-to-protein conversion factors for 19 tropical seaweeds

Abstract: SUMMARY The use of nitrogen-to-protein conversion factors (N-Prot factors) is the most practical way of determining protein content. The accuracy of protein determination by this method depends on the establishment of N-Prot factors specific to individual species. Experimental data are needed to allow the use of this methodology with seaweeds. The present study was designed to characterize the amino acid composition and to establish specific N-Prot factors for six green, four brown and nine red marine algae. Mean values for individual amino acids tended to be similar among the three groups, but some differences were found. Green algae tended to show lower percentages of both aspartic acid and glutamic acid than the other two groups of algae. The percentages of both lysine and arginine were higher in red algae, while brown algae tended to show more methionine than green and red algae. The actual protein content of the species, based on the sum of amino acid residues, varied from 10.8% (Chnoospora minima, brown algae) to 23.1% (Aglaothamnion uruguayense, red algae) of the dry weight. Nitrogen-toprotein conversion factors were established for the species studied, based on the ratio of amino acid residues to total nitrogen, with values ranging from 3.75 (Cryptonemia seminervis, red algae) to 5.72 (Padina gymnospora, brown algae). The relative importance of non-protein nitrogen is greater in red algae, and consequently lower N-Prot factors were calculated for these species (average value 4.59). Conversely, protein nitrogen content in both green and brown algae tends to be higher, and average N-Prot factors were 5.13 and 5.38, respectively. An overall average N-Prot factor for all species studied of 4.92 ± 0.59 (n = 57) was established. This study confirms that the use of the traditional factor 6.25 is unsuitable for seaweeds, and the use of the N-Prot factors proposed here is recommended.

The phylogenetic relationship between the Chlamydomonadales and Chlorococcales inferred from 18SrDNA sequence data

Abstract: SUMMARY Nuclear-encoded small subunit ribosomal RNA gene (185rDNA) sequences were determined for Chlamydomonas moewusii Gerloff and five chlorococcalean algae (Chlorococcum hypnosporum Starr; Chlorococcum oleofaciens Trainor et Bold; Chlorococcum sp.; Tetracystis aeria Brown et Bold; Protosiphon botryoides (Kutzingl Klebs). All these algae are characterized by a clockwise CCW) flagellar apparatus. Phylogenetic trees were constructed from sequences from these algae together with 20 green algae. All algae with a CW flagellar apparatus form a monophyletic clade (CW group). Three principal clades can be recognized in the CW group, although no morphological character supports monophyly of any of these three clades. The 185rDNA trees clearly demonstrate the non-monophyly of the Chlamydomonadales and Chlorococcales, suggesting that vegetative morphology does not reflect phylogenetic relationships in the CW group. The paraphyly or polyphyly of the genus Chlamydomonas and Chlorococcum are also revealed. Present analysis suggests that the presence or absence of a zoospore's cell wall and the multinucleate condition have limited taxonomic values at higher taxonomic ranks.

Research note: Identity of the Qingdao algal bloom

Abstract: In early July 2008, news agencies worldwide reported on a vast algal bloom that was threatening the upcoming Olympic sailing events in Qingdao, China. The identity of the culpable alga, however, remained undiscussed. We have identified the alga that caused the bloom by means of morphological and molecular data, including sequence data of the plastid encoded large subunit ribulose 1,5-bisphosphate carboxylase gene (rbcL) and the nuclear encoded rDNA internal transcribed spacer (ITS) region. The bloom-forming alga falls within the morphological limits of the green seaweed Ulva prolifera O.F. Muller ('Enteromorpha prolifera (O.F. Muller) J. Agardh') but our phylogenetic analyses show that it forms a clade with representatives of the Ulva linza-procera-prolifera (LPP) complex. The Chinese rbcL sequences are identical to those of specimens collected from Japan, New Zealand, Finland and Portugal, suggesting that the taxon is widely distributed. rDNA ITS sequences showed a close affinity with Japanese isolates of the species complex. The Qingdao bloom is a typical illustration of a green tide, which occurs increasingly along several coasts worldwide. © 2009 Japanese Society of Phycology.

Molecular phylogenetic analyses of the Japanese Ulva and Enteromorpha (Ulvales, Ulvophyceae), with special reference to the free-floating Ulva

Abstract: SUMMARY In order to elucidate the species composition of freefloating Ulva that cause green tide in several bays in Japan, and to clarify the generic status of Ulva and Enteromorpha (Ulvales, Ulvophyceae), the nuclear encoded internal transcribed spacer (ITS) region including the 5.8S gene and the plastid encoded large subunit of ribulose-1, 5-bisphosphate carboxylase/ oxgenase ( rbc L) gene sequences for 15 species were determined. Both ITS and rbc L analyses indicate that free-floating Ulva samples are divided into four different lineages that correspond to Ulva lactuca Linnaeus, U. pertusa Kjellman, U. armoricana Dion et al . and U. fasciata Delile. These four species are distinguished by cell morphology including the arrangement of cells, the shape and size of cells and the position of chloroplasts. Molecular data also indicated that Ulva and Enteromorpha are not separated as respective monophyletic groups within a large monophyletic clade and congeneric as shown by previous molecular studies using the ITS sequences alone. This strongly suggests that these genera are congeneric and Enteromorpha should be reduced to the synonym of Ulva .