FasL is more frequently expressed in liver metastases of colorectal cancer than in matched primary carcinomas

Colorectal carcinoma cells have recently been shown to express Fas ligand (FasL). This ligand could allow the tumour cells to evade activated tumour-infiltrating lymphocytes (TILs) by inducing their apoptosis and would thus promote tumour survival and possibly metastasis formation. To test this hypothesis in vivo we analysed the expression of FasL mRNA and protein in paired tissue samples of normal colonic mucosa (N), primary colorectal carcinomas (T) and their metastases (M) from a total of 21 patients by four different methods. Additionally, the presence and activation status of infiltrating lymphocytes, which might contribute to the total amount of FasL in the tissue, was determined by semiquantitative reverse transcription–polymerase chain reaction (RT–PCR) in the same samples. The frequency of FasL detection was 30–40% in T and was 60–100% in M, depending on the sensitivity of the method. Simultaneously, the amount of CD25 mRNA, used as a measure of the number of activated TILs, was in 90% of patients lower in M than in T. The increased frequency of FasL detection in liver metastases was therefore not due to the presence of activated TILs. We conclude that metastasizing subpopulations of colorectal tumour cells express FasL more frequently than the primary carcinomas and may be able to eliminate activated TILs in vivo via Fas/FasL-induced apoptosis or other hitherto unknown mechanisms. © 1999 Cancer Research Campaig

A reassessment of the Hypoglossum group (Delesseriaceae, Rhodophyta), with a critique of its genera

A reassessment of the Hypoglossum group (Delesseriaceae, Rhodophyta), with a critique of its genera. Eight genera are assigned to the Hypoglossum Kützing, Phitymophora J. Agardh, Pseudobranchioglossum Bodard, and Zellera Martens. The circumscription of the group is emended to include forms with network-forming ( Zellera ) an dspirally twisted ( Duckerella ) thalli. The definition of the group is lalso modified to include members (e.g. some species of Hypoglossum ) in which tetrasporangia are produced by primary cells as in the Caloglossa group. Exogenous branching, a distinguishing feature of the closely related Caloglossa group, never occurs in the Hypoglossum group.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47938/1/10152_2006_Article_BF02365624.pd

Porphyra birdiae sp. nov. (Bangiales, Rhodophyta): a new species from the northwest Atlantic

Recent studies combining biochemical, molecular, and traditional morphological and ecological traits have shown that some currently recognized species of the red algal genus Porphyra are actually form species or complexes comprising several morphologically similar but genetically distinct taxa. Conflicting reports of chromosome numbers and differences in DNA sequences for Porphyra purpurea (Roth) C. Agardh have raised suspicion that more than one taxon has been confused under this name in the Northwest Atlantic. We have identified one of these cryptic taxa and describe it here as a new species, Porphyra birdiae. Like P. purpurea, it has an ovate to broadly elongate, foliose blade with reproductive areas segregated by a distinct line into male and female sectors. While reproductive specimens have historically been confused with P. purpurea, non-reproductive specimens of P. birdiae have been incorrectly identified as P. umbilicalis Kutzing. Although P. birdiae is morphologically similar to both of these species, sequences of SSU (nuclear small subunit rRNA gene) and rbcL (plastid ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit gene) indicate that it is not closely related to either one. Based on rbcL sequences, P. birdiae is closely related to P. aestivalis Lindstrom et Fredericq, a proposed new species from Alaska

Identification of north-western Atlantic Porphyra (Bangiaceae, Bangiales) based on sequence variation in nuclear SSU and plastid rbcL genes

Six species of Porphyra have commonly been recognized in the north-western Atlantic from Long Island Sound to the Canadian Maritimes: P. amplissima, P. leucosticra, P. linearis, P. miniata, P. purpurea, and P. umbilicalis. Distinguishing them with certainty has been problematic. A DNA-based system of molecular identification was developed using partial sequences of the nuclear small subunit ribosomal RNA gene (SSU) or the plastid ribulose-1,5-bisphosphate carboxylase–oxygenase large subunit gene (rbcL). Multiple samples of each taxon were surveyed for intraspecific variation. Intraspecific SSU divergences for Porphyra ‘leucosticta’, P. ‘miniata’, P. ‘umbilicalis’, and P. ‘purpurea’ ranged from 0% to 1%. There was more variation for P. ‘amplissima’ (0–2.1%) and P. ‘linearis’ (0–3.5%); however, each taxon was monophyletic. No intraspecific differences were observed for these taxa in rbcL (one to eight samples per taxon). These sequences were compared with P. yezoensis U51, introduced to Maine, and with P. ‘dioica’, a north-east Atlantic Porphyra easily confused with P. ‘purpurea’. To discriminate between P. ‘purpurea’, P. ‘umbilicalis’, and P. ‘leucosticta’, SSU variation was used to design primers for the Allele-Specific Polymerase Chain Reaction™. With molecular tools, we could classify over 80% of the monostromatic specimens surveyed, but the residue of unidentifiable specimens may indicate the existence of further monostromatic species in the north-west Atlantic. Porphyra ‘purpurea’ was found to occur further south than previously recorded. A morphologically cryptic Porphyra was discovered at Herring Cove, Nova Scotia, Canada.† Phylogenetic analyses using SSU or rbcL sequences showed ‘soft incongruence’ between gene trees, i.e. the topologies of the phylograms were similar but not identical, with only weak to moderate bootstrap support for the nodes that differed. Both trees strongly supported a clade including P. ‘purpurea’, P. ‘umbilicalis’, P. ‘linearis’, and P. ‘dioica’. Porphyra sp. Herring Cove was allied with the remaining Porphyra taxa in the SSU tree. The rbcL phylogeny was less well resolved, consisting of a polytomy of a P. ‘purpurea’–P. ‘umbilicalis’–P. ‘linearis’–P. ‘dioica’ clade, Porphyra sp. Herring Cove, a clade comprising P. ‘amplissima’ and P. ‘miniata’, and a P. ‘suborbiculata’–P. ‘leucosticta’–P. yezoensis clade