Regulation of cellular adhesion molecule expression in murine oocytes, peri-implant ation and post-implantation embryos

Expression of the adhesion molecules, ICAM-1, VCAM-1, NCAM, CD44, CD49d (VLA-4, a chain), and CDlla (LFA-1, a chain) on mouse oocytes, and pre- and peri-implantation stage embryos was examined by quantitative indirect immunofluorescence microscopy. ICAM-1 was most strongly expressed at the oocyte stage, gradually declining almost to undetectable levels by the expanded blastocyst stage. NCAM, also expressed maximally on the oocyte, declined to undetectable levels beyond the morula stage. On the other hand, CD44 declined from highest expression at the oocyte stage to show a second maximum at the compacted 8-cell/morula. This molecule exhibited high expression around contact areas between trophecto-derm and zona pellucida during blastocyst hatching. CD49d was highly expressed in the oocyte, remained significantly expressed throughout and after blastocyst hatching was expressed on the polar trophecto-derm. Like CD44, CD49d declined to undetectable levels at the blastocyst outgrowth stage. Expression of both     

The state of play of farmland birds: population trends and conservation status of lowland farmland birds in the United Kingdom

Many bird species of lowland farmland have declined substantially in the United Kingdom over the past 30 years. Declines among farmland specialists are steeper than for generalists and were most rapid for these specialists in the 1970s and 1980s. These changes have been linked to increased agricultural intensification and are reflected in Red or Amber conservation concern status for many common farmland species, as well as for rarer ones. We review long- and short-term population trends and the conservation status of lowland farmland birds in the UK using the latest available information from bird surveys, and examine patterns among species. Analyses of demographic parameters suggest broadly that the key factor driving population changes of seed-eating and migrant birds is overwinter survival, whereas for many non-passerine species population growth appears to be limited by productivity. Population trends for a suite of lowland farmland species were first combined in the UK Government's headline wild bird indicator published in 1998. This 'Skylark index' as it is sometimes known was intended to reflect the health of the wider countryside and struck a chord with the public and decision-makers. We look at the behaviour of the composite indicator and explore the population dynamics of the increasing and declining species separately. Simple models of population growth in these groups are then used to explore plausible scenarios for delivering the Government's Public Service Agreement target to reverse the long-term decline in the number of farmland birds by 2020.     

Archaeophytes in Britain

The concept of 'archaeophytes' (alien taxa which became established in a study area before AD  1500) is widely used in floristic analyses in central and northern Europe, but few authors have applied it to the British flora. Six criteria for the recognition of archaeophytes are outlined, drawing upon evidence of fossil and recent history, current habitat and European and extra-European distribution. These are used to identify 157 probable archaeophytes in Britain. Only five of these are known from fossil records from the Neolithic; most are first recorded in archaeological contexts in the Late Bronze Age, Iron Age, Roman or Medieval periods. As a group, archaeophytes (unlike neophytes) have declined in Britain in the 20th century. Comparison of the accepted status of these species in the Czech Republic, Germany, Poland and Finland demonstrates that over 50% are treated as archaeophytes in central Europe, but in Finland many are absent or only present as casual introductions. Species regarded as archaeophytes in these countries but as natives in Britain are also reviewed. The indirect nature of the evidence used to identify archaeophytes means that it is usually impossible to be certain about the history of a species; in particular, archaeophytes which have successfully invaded semi-natural habitats are likely to be overlooked as natives. The suggestion that a species is an archaeophyte is best regarded as a hypothesis to be tested by further studies. There is considerable scope for archaeological investigations aimed at addressing these botanical problems.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 257−294.     

The first British record and a new species of the superfamily Terrestricytheroidea (Crustacea, Ostracoda): morphology, ontogeny, lifestyle and phylogeny

Terrestricythere elisabethae sp. nov. is described from a semiterrestrial coastal habitat at two sites in Hampshire, southern England. It is the first record of a living population of the genus outside the Far East (north-west Pacific). Based on extensive collections and from observations of cultures, its morphology is described (including a formal definition of the unique 'visordont' hinge), as well as its ontogeny and lifestyle (encompassing habitat, life cycle, mode of life and locomotion). A further new species from Somerset, south-west England is also recorded on the basis of a single specimen but left in open nomenclature. The affinities of the Terrestricytheroidea are discussed in the context of a tentative phylogeny of podocopan Ostracoda. Both carapace and appendage characters are such as to warrant maintaining it as a separate superfamily, which is more closely related to the Cytheroidea and Darwinuloidea than to the Cypridoidea.  © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society , 2004, 142 , 253–288.     

Development and characterization of microsatellite loci in the endangered oyster mussel Epioblasma capsaeformis (Bivalvia: Unionidae)

Primers for 10 polymorphic microsatellite loci were developed and characterized for the endangered oyster mussel Epioblasma capsaeformis from the Clinch River, Tennessee. Microsatellite loci also were tested in four other populations or species. Amplification was successful for most loci in these closely related endangered species or populations; therefore, a high level of flanking sequence similarity was inferred for this group of species and populations. Allelic diversity ranged from nine to 20 alleles/locus, and averaged 13.6/locus. This study demonstrated the feasibility of using polymerase chain reaction (PCR) primers to amplify microsatellite loci across freshwater mussel species to conduct population genetics studies.     

Tracing the tropics across land and sea: Permian to present

The continuity through the past 300 million years of key tropical sediment types, namely coals, evaporites, reefs and carbonates, is examined. Physical controls for their geographical distributions are related to the Hadley cell circulation, and its effects on rainfall and ocean circulation. Climate modelling studies are reviewed in this context, as are biogeographical studies of key fossil groups. Low-latitude peats and coals represent everwet climates related to the Intertropical Convergence Zone near the Equator, as well as coastal diurnal rainfall systems elsewhere in the tropics and subtropics. The incidence of tropical coals and rainforests through time is variable, being least common during the interval of Pangean monsoonal climates. Evaporites represent the descending limbs of the Hadley cells and are centred at 10° to 40° north and south in latitudes that today show an excess of evaporation over precipitation. These deposits coincide with the deserts as well as seasonally rainy climates, and their latitudinal ranges seem to have been relatively constant through time. Reefs also can be related to the Hadley circulation. They thrive within the regions of clear water associated with broad areas of downwelling which are displaced toward the western portions of tropical oceans. These dynamic features are ultimately driven by the subtropical high-pressure cells which are the surface signature of the subsiding branches of the Hadley circulation. Carbonates occupy the same areas, but extend into higher latitudes in regions where terrestrial surface gradients are low and clastic runoff from the land is minimal. We argue that the palaeo-latitudinal record of all these climate-sensitive sediment types is broadly similar to their environments and latitudes of formation today, implying that dynamic effects of atmospheric and oceanic circulation control their distribution, rather than temperature gradients that would expand or contract through time.     

A molecular phylogeny of the peacock-pheasants (Galliformes: Polyplectron spp.) indicates loss and reduction of ornamental traits and display behaviours

The South-east Asian pheasant genus Polyplectron is comprised of six or seven species which are characterized by ocelli (ornamental eye-spots) in all but one species, though the sizes and distribution of ocelli vary among species. All Polyplectron species have lateral displays, but species with ocelli also display frontally to females, with feathers held erect and spread to clearly display the ocelli. The two least ornamented Polyplectron species, one of which completely lacks ocelli, have been considered the primitive members of the genus, implying that ocelli are derived. We examined this hypothesis phylogenetically using complete mitochondrial cytochrome b and control region sequences, as well as sequences from intron G in the nuclear ovomucoid gene, and found that the two least ornamented species are in fact the most recently evolved. Thus, the absence and reduction of ocelli and other ornamental traits in Polyplectronare recent losses. The only variable that may correlate with the reduction in ornamentation is habitat, as the two less-ornamented species inhabit montane regions, while the ornamented species inhabit lowland regions. The implications of these findings are discussed in light of models of sexual selection. The phylogeny is not congruent with current geographical distributions, and there is little evidence that Pleistocene sea level changes promoted speciation in this genus. Maximum likelihood and maximum parsimony analyses of cytochrome b sequences suggest that the closest relatives of Polyplectron are probably the peafowl and the argus pheasants.     

Lack of Influence of the Epidermis on Underlying Cell Development in Leaflets ofPisum sativumvar.argenteum(Fabaceae)

We explored whether epidermal pressure regulates cell and organgrowth in leaflets ofPisum sativumvar.argenteum,a mutant cultivarof the garden pea characterized by reduced adhesion betweenthe epidermis and subjacent mesophyll. Developing leaflets ofleaves arising at three positions on the seedling axis werepeeledin situand grown to maturity in humidity chambers. Themature anatomy and morphology could be accurately assessed becausewound responses normally associated with peeling were preventedby theArgmutation that permitted peeling without damage to themesophyll and by the humidity chambers that protected peeledareas from desiccation. The mesophyll cell size, state of differentiation,and layering pattern as well as the overall morphology of mature,peeled leaflets were indistinguishable from those of mature,intact leaflets grown under the same conditions. The epidermisexerted no detectable regulatory effect on the expansion ofthe leaflets as a whole or on the tissue layers and cells withinthe leaflets.Copyright 1999 Annals of Botany Company. Biomechanics, compression, epidermis, leaf development, mesophyll, pressure, wound response,Pisum sativumvar.argenteum.     

Regeneration of Hydra from Reaggregated Cells

Separated cells of hydra reaggregate and develop into normal animals. The regeneration of serially grafted aggregates derived from different parts of hydra tissue demonstrates that the polarity of morphogenesis in hydra is the result of the cellular composition of the tissue, not cellular orientation.