CNS stem cells: Where's the biology (a.k.a. beef)?

Central nervous system (CNS) stem cells have become the subject of many laboratories' efforts, presentations, and publications. Yet, in the stem cell world, CNS cells are viewed with skepticism. This is likely due to a dearth of biology (in vivo function) to accompany a flurry of phenomenological and restorative neurology studies. In this article, we compare and contrast the biological knowledge of adult forebrain epidermal growth factor-responsive neural stem cells that has emerged from our laboratories with that of hematopoietic stem cells, using two recent papers in the latter field as specific examples. A comparison of stem cell location, lineage, and repopulation suggests that our understanding of CNS stem cell biology is immature. We conclude that a greater focus on in vivo biology will enhance our knowledge and understanding of CNS stem cells. © 1998 John Wiley & Sons, Inc. J Neurobiol 36: 307–314, 1998     

Olpidiopsis antithamnionis n. sp. (Oomycetes,Olpidiopsidaceae), a parasite of Antithamnion floccosum (O. F. Müll.) Kleen from Newfoundland

Summary Olpidiopsis antithamnionis n. sp. (Oomycetes, Olpidiopsidaceae) parasitic on Antithamnion floccosum (O. F. Müll.) Kleen (Rhodophyta, Ceramiaceae) is described from three sites in Newfoundland, Canada, and from culture.Axial cells of the main and determinate branches of the host are the primary sites of fungal attack, although tetrasporangia and rhizoidal cells are also susceptible. Successful re-infection of A. floccosum was achieved in the laboratory although A. boreale and the trailliella-phase of Bonnemaisonia hamifera, both occurring with A. floccosum in the field, were immune. Regeneration of the host cells was observed, a phenomenon not previously reported in the fungal parasitism of other filamentous benthic marine algae.Studies in Biology from Memorial University of Newfoundland No. 256.     

Neotropical monogenea. 13. Rhinonastes pseuodocapsaloideum n. gen., n. sp. (Dactylogyridae, Ancyrocephalinae), a nasal parasite of curimat?, Prochilodus nigricans Agassiz (Cypriniformes, Prochilodontidae), in Brazil

Rhinonastes pseudocapsaloideum n. sp. (Dactylogyridae, Ancyrocephalinae) is described from the nasal cavity of Prochilodus nigricans Agassiz (Cypriniformes, Prochilodontidae) in Brazil. Rhinonastes n. gen. is proposed for species possessing a dextroventral genital pore, a bilobed testis, a ventral C-shaped ovary lying between the 2 testicular lobes, and a disc-shaped haptor armed with a ventral anchor-bar complex and 14 hooks.     

Angiopteris sparsisora Ching,sp. nov.—a putative bigeneric hybrid

Angiopteris sparsisora Ching, sp. nov. Species nova ab omnibus affinibus adhuc cognitis recedit rhizomate repente, dorsiventrali, habitu minore stipite tenui, levi, paleis brunneis lineari-lanceolatis margine irregulariter fimbriatis peltati-fixis, pinnulis basi cuneatis vel late cuneatis, distincte breviterque petiolulatis, soris longitudine variis, inter se separatis a margine magis remotis, paraphysibus rudimentalibus brevibus sparse praesentibus. Tota planta 1—1.2 m alata, rhizomate repente, carnoso, cylindrico, dorsiventrali, 5—6 cm diametro, radicoso, apice frondes 2—3 emittente, stipite 35—70 cm longo, 4—8 mm crasso, levi viridi, supra medium uni-geniculato (in frondibus pinnatis usque subbipinnatis), paleis brunneis lineari-lanceolatis basi rotunda peltati-fixis margine varie fimbriatis sparse vestito; lamina stipite longiore, bipinnata aut subb ipinnata raro superne simpliciter pinnata; pinnis 2—3(—7)-jugis, ,alternis vel suboppositis, oblongis, 45—55 cm longis, 18—23 cm latis, petiolo 4—16 cm longo suffultis, basi tumidis, pinnatis vel interdum simplicibus vel basi pinnatifidis; pinnulis plerumque 8—12-jugis, alternis vel suboppositis, patentibus, 8—18 cm longis, medio 1.5—3cm latis, lanceolatis, acuminatis, basin versus cuneatis vel late cuneatis, breviter petiolatis, pinnula terminali confomi paulo majore, petiolulata, hasi baud in alas decurrente, margine serrulatis; venis utrinquo distinctis, patentibus, simplicibus vel furcatis, prope marginem curvatis; pagina frondis textura in sicco virescente, chartacea, rachi, costis, costulis venisque subtus sparsim minuteque paleaceis. Soris breviter linearibus, 2—4 mm longis, 10—32-sporangiatis, inter se separatis, a margine 2—3 mm, remotis; paraphysibus sparsis brevibusrudimentalibus. Sporis globulosis, suparficie dense tubuculatis. Yunnan austro-orientalis: Xichou Xian, Fadou, S. K. Wu 4203 (typus, PE), 4198, 8, October, 1962; ibidem, Z. R. Wang 566-1, 566-2, 566-3, 566-4, 566-5, 15, January, 1978; ibidem V. M. Chu 8212, 15, January, 1978. in valley under evergreen broadleaved forests, alt. 1500—1550m. In the tropical rain forest in southeastern Yunnan, China, the members of Angiopteris Hoffm. and Archangiopteris Christ et Gies. are often growing side by side in great abundance. In January 1978 the second writer made a botantical trip there and collected in one locality ample herbarium material of an Angiopteris, which is identical with A. sparsisora Ching (ined.), based upon type specimens gathered by Mr. S. K. Wu from the same locality in 1962. To our great surprise, however, this distinct taxon reveals a number of important morphological characteristics intermediate between Angiopteris and Archangiopteris as diagnosed above. The present species resembles Archangiopteris in small build with creeping dorsiventral rhizome, unigeniculate, thin, smooth stipe in pinnate to bipinnatifid fronds, sparingly clad in linear-lanceolate peltately affixed scales with variously fimbriate margin, lamina 1—2 pinnate or subbipinnate, pinnules distinctly and shortly stipitate, base cuneate or broadly cuneate, sori of different length separated from each other by broad spaces, and rather far away (2—3 mm) from the margin, paraphyses few, rudimentary and short, but, on the other hand, it also similar to Angiopteris in usually bipinnate fronds, the petiole of pinnae with swollen base (blackish upon drying), short (2—4 mm long) linear sori consisting of 5—16 pairs of sporangia and globulax spores with densely tubucular sporoderms. All the above characteristics combined clearly indicate the species is in all likelihood a natural hybrid between Angiopteris and Archangiopteris, pending cytological investigation and the reason for presently placing it in Angiopteris rather than in Archangiopteris is because of the fact that in overall impression the newtaxon appears more like the former than the latter.     

Ephemerella readeri Müll. Hal. (Physcomitrella readeri (Müll. Hal.) I.G. Stone & G.A.M. Scott,Funariidae, Bryophyta): a genus and species new to Europe

Abstract

A morphological and molecular analysis of a Physcomitrella, collected from a reservoir margin in the north of England, revealed this to be P. readeri, a species new to Europe. The present study clarifies previous confusion over the taxonomy of P. readeri showing it to be clearly distinct in both sporophytic and gametophytic characters from P. patens and uniform across its world range from England to USA, Japan and Australasia. While phylograms of the ITS1 region from both the Physcomitrella species, Physcomitrium pyriforme (Hedw.) Bruch & Schimp., Enthosthodon attenuatus (Dicks.) Bryhn and Funaria hygrometrica Hedw., place the first two in separate clades, in ITS2 phylograms they occur as sister taxa. This, together with previous genealogical studies on the speciation history of the Physcomitrella–Physcomitrium species complex, and morphology, suggests that generic rank is appropriate for P. readeri. We therefore reinstate the original name Ephemerella readeri Müll. Hal. Recent records at several reservoirs in England indicate that E. readeri may be native to UK, though remarkable congruence in ITS1 with Australian plants also suggests recent arrival as an alternative possibility.