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Genetic polymorphisms were investigated to develop a simple and rapid method to differentiate between the two closely related species, Porphyra tenera and Porphyra yezoensis. Polymerase chain reaction (PCR) using the specific primer pair of the ARP4 gene gave length polymorphic single fragments of genomic DNAs from five strains of P. tenera (Japan T-8, JTW; Korea KTY1, KTY2, KTY3) and seven strains of P. yezoensis (Japan TU-1, TU-2, TUH-25, JHU, JA-1; Korea KGJ, KPH). All strains of P. yezoensis had introns 60 bp longer than that of P. tenera. Multiple cleaved amplified polymorphic sequence (CAPS) markers were also developed to differentiate P. tenera and P. yezoensis. This is the first report of length polymorphisms that can be used to differentiate between the two species using only PCR amplification with agarose gel electrophoresis. It is expected that the length polymorphism and plentiful CAPS profiles obtained in this study will be useful in the assessment of genetic diversity within P. tenera and P. yezoensis as well as in breeding science that requires the collection of various strains of the two species. [ABSTRACT FROM AUTHOR]

The cell-cycle progression of Enteromorpha compressa (L.) Nees (= Ulva compressa L.) was diurnally regulated by gating the G1/S transition. When the gate was open, the cells were able to divide if they had attained a sufficient size. However, the cells were not able to divide while the gate was closed, even if the cells had attained sufficient size. The diurnal rhythm of cell division immediately disappeared when the thalli were transferred to continuous light or darkness. When the thalli were transferred to a shifted photoperiod, the rhythm of cell division immediately and accurately synchronized with the shifted photoperiod. These data support a gating-system model regulated by light:dark (L:D) cycles rather than an endogenous circadian clock. A dark phase of 6 h or longer was essential for gate closing, and a light phase of 14 h was required to renew cell division after a dark phase of >6 h. [ABSTRACT FROM AUTHOR]

Asexual reproduction via archeospores in Porphyra yezoensis Ueda gametophytes is a very valuable character to nori farming; however, there is little information available on the molecular basis of the developmental process. To identify genes involved in the Porphyra asexual sporulation, we compared the gene expression profiles derived from four developmental stages of the life cycle (three from gametophytes; one from sporophytes) using cDNA macroarray, which includes 4,896 nonredundant expressed sequence tag (EST) groups. Candidate genes were screened by two different macroarray data analyses combined with reverse transcription-PCR (RT-PCR) analysis or Northern analysis. RT-PCR analysis revealed that nine genes (one: similarity to 5′–3′ exoribonuclease; the other eight: no sequence similarity to known proteins) were expressed with a gametophyte (G)–specific manner, and two genes (named ASPO2608, ASPO1527) were expressed only in gametophytes that formed archeospores. The deduced amino acid sequences for the latter two genes are predicted to contain signal peptides for secretion at their N-termini. Northern analysis revealed that expression levels of Calvin cycle genes in the gametophytic stage that formed archeospores (G-A stage) were higher than those of the gametophyte blade with no archeospores (G-NA stage). In the macroarray analysis based on the rank data of G-preferentially expressed genes, which were detected in the previous P. yezoensis EST analysis, one gene encoding the cyclase associated protein (CAP) exhibited a change upwardly in the G-A stage >1,000 ranks to the G-NA stage. We propose that ASPO2608 and CAP may function in a signaling pathway of asexual sporulation. [ABSTRACT FROM AUTHOR]

We investigated genetic diversity in 10 strains of Porphyra yezoensis and related species, collected from Japan and Korea, in order to identify an appropriate crossing partner for use in various genetic analyses. Firstly, the phylogenetic relationships among the 10 strains were examined using SSU rDNA sequences. All five Japanese strains (TU-1, TU-2, TUH-25, JHS and JHU) and two of the Korean strains (KGJ and KPH) were identified as P. yezoensis while the other three Korean strains (KTY1, KTY2 and KTY3) were identified as P. tenera. Using cleaved amplified polymorphic sequence analysis, genetic polymorphisms lying in five regions of four genes (ß-tubulin, TOP2, EF-1α and V-ATPase) were examined. Twenty out of 34 restriction endonucleases revealed genetic polymorphisms between the seven strains of P. yezoensis and the three strains of P. tenera in all five regions tested. Furthermore, when they were employed to digest the fragments of TOP2 and V-ATPase, 14 enzymes discriminated the two Korean strains of P. yezoensis (KGJ and KPH) from the five Japanese strains of this species. The level of polymorphism was much higher in the amplified fragment of V-ATPase (including four introns) than in that of TOP2 without an intron. The gene regions with detected polymorphisms would be useful molecular markers for confirmation of cross-fertilization in sporophytic thalli and for construction of a linkage map. A suitable combination of the strains in the cross experiment is discussed. [ABSTRACT FROM AUTHOR]

We report the nucleotide sequence of a gene encoding the c (‘16 kDa’) subunit of the vacuolar-type H+-ATPase (V-ATPase) from a marine red alga, Porphyra yezoensis. A cDNA clone was isolated from a leafy gametophyte cDNA library and analyzed for the sequence. The genomic DNA sequence was directly determined by nested PCR. The structural gene contained four introns within a coding sequence of 483 base pairs which encodes a polypeptide of 161-amino acids with four hydrophobic transmembrane-spanning regions. Comparison of the deduced amino acid sequences showed higher similarity to the land plant Oryza sativa (69.1%) than to the Ulvophyceae Acetabularia acetabulum (64.1%). The mRNA was detected bothin the leafy gametophytes and filamentous sporophytes. [ABSTRACT FROM PUBLISHER]

We developed a method for extraction of DNA front he red alga Porphyra yezoeitsis Ueda. The method consists of three preparation steps that include CsCl-gradient ultracentrifugution. cetyl trimethyl ammonium bromide treatmetn, and a final RNase step. The amount of DNA extracted from 1.5 g of starting material averaged 17.7 μg. the resulting DNA had a high molecular weight, was 25166 k in length, was digested with five common restriction enzymes, and showed no nuclease activity. It was of sufficient quality for construction of genomis libraries. [ABSTRACT FROM AUTHOR]

The cell-cycle progression of Enteromorpha compressa (L.) Nees (=Ulva compressa L.) was diurnally regulated by gating the G1 /S transition. When the gate was open, the cells were able to divide if they had attained a sufficient size. However, the cells were not able to divide while the gate was closed, even if the cells had attained sufficient size. The diurnal rhythm of cell division immediately disappeared when the thalli were transferred to continuous light or darkness. When the thalli were transferred to a shifted photoperiod, the rhythm of cell division immediately and accurately synchronized with the shifted photoperiod. These data support a gating-system model regulated by light:dark (L:D) cycles rather than an endogenous circadian clock. A dark phase of 6 h or longer was essential for gate closing, and a light phase of 14 h was required to renew cell division after a dark phase of >6 h., (© 2008 Phycological Society of America.)