Apogamous sporophyte formation in a fernPteris multifida and its characteristics

When spores of the fern,Pteris multifida, were aseptically cultured in the dark, sporophytic plants were apogamously induced. The plants have been subsequently grown in pots until the development of leaves with many sporangia for observations of meiotic characteristics in their sporocytes. The sporophytic plants originated from spores were estimated to be haploid, and the estimation was supported by abnormal meiosis in sporocytes and the absence of mature spores, but some chromosomes (n=58) formed bivalents in the meiotic process.     

Human hand impedance characteristics during maintained posture

Received: 23 June 1993 / Accepted in revised form: 15 September 1994     

Egg cluster size variation in relation to the larval food abundance inLuehdorfia puziloi (Lepidoptera: Papilionidae)

Mean egg cluster size of Luehdorfia puziloi yessoensis varied among habitats. The mean egg cluster size tended to be large when abundance of the larval food leaves expressed as the fresh weight of leaves per unit area at a given habitat was high. Since this variation was observed among closely located study plots (butterflies can easily move between study plots), the egg cluster size variation among habitats is likely to be a result of flexible response by females to varying food abundance for larvae.     

A water channel of the nematode C.elegans and its implications for channel selectivity of MIP proteins

A genome project focusingon the nematode Caenorhabditis elegans has demonstrated thepresence of eight cDNAs belonging to the major intrinsic proteinsuperfamily. We functionally characterized one of these cDNAs namedC01G6.1. Injection of C01G6.1 cRNA increased the osmotic waterpermeability (P_f) of Xenopusoocytes 11-fold and the urea permeability 4.5-fold but failed toincrease the glycerol permeability. It has been speculated that the MIPfamily may be separated into two large subfamilies based on thepresence or absence of two segments of extra amino acid residues (~15amino acids) at the second and third extracellular loops. BecauseC01G6.1 (designated AQP-CE1), AQP3, and glycerol facilitator (GlpF) all have these two segments, we replaced the segments of AQP-CE1 with thoseof AQP3 and GlpF to identify their roles. The functional characteristics of these mutants were principally similar to that ofwild-type AQP-CE1, although the values of P_f andurea permeability were decreased by 39-74% and 28-65%,respectively. These results suggest that the two segments of extraamino acid residues may not contribute to channel selectivity orformation of the route for small solutes.

     

Inhibitory CD161 receptor identified in glioma-infiltrating T cells by single-cell analysis

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