New morphological evidence supports congruent phylogenies and Gondwana vicariance for palaeognathous birds

There has been little agreement on the phylogeny of palaeognathous birds, with major differences amongst and between results from morphological and molecular data. Two recently published phylogenies using nuclear and mitochondrial DNA have substantial agreement in overall topology, with the ostrich as sister group of all other extant palaeognaths and a kiwi‐emu‐cassowary clade. Here I report a morphological phylogeny based mainly on new characters from the tongue apparatus and cranial osteology, with a theoretical ancestor as outgroup. A new interpretation of the evolution of the avian palate is included. This phylogeny is very similar to these recent molecular results; this is the first report of such congruence, and offers a credible basis for understanding the evolution of this clade. This phylogeny is fully consistent with a Gondwana vicariance model of evolution. Dates attributed from known geological events place the first extant radiation (ostrich) in the mid‐Cretaceous, and offer a means of calibration of future molecular clock investigations. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 959–983.     

Uptake of CO2 by aquatic vegetation

Abstract Photosynthesis by aquatic plants based on the supply of CO₂ from air-equilibrated solutions may be limited by the low diffusion coefficient of CO₂ in water. For plants in which the transport of CO₂ from the bulk medium is by diffusion, and the initial carboxylation uses RUBISCO, CO₂ supply can be increased by growth in habitats with fast water flow over the surface (reducing unstirred layer thickness), or with heterotrophically-augmented CO₂ levels, including the direct use of sediment CO₂. Many aquatic plants using RUBISCO as their initial carboxylase counter the limitations on CO₂ supply via the operation of biophysical CO₂ concentrating mechanisms which are based on active transport of HCO^?₃, CO₂ or H⁺ at the plasmalemma, and use bulk-phase HCO^?₃ or CO₂ as the C source. A final group of aquatic plants use biochemical CO₂ concentrating mechanisms based on auxiliary carboxylation by PEPc: C₄-like and Crassulacean Acid Metabolism–like processes are involved. These various mechanisms for increasing CO₂ supply to RUBISCO also help to offset the low specific reaction rate of aquatic plant RUBISCOs at low [CO₂] and low [CO₂]: [CO₂]. In addition to overcoming restrictions on CO₂ supply, the various methods of increasing inorganic C availability may also be important in alleviating shortages of nitrogen or photons.     

The articulation of annelids

The aim of this paper is to assess the monophyly of the Annelida. Also, recent cladistic analyses of metazoan taxa, using a variety of data, have shown incongruities with regards to annelids and associated taxa that should be resolved. The Platyhelminthes is selected as the taxon to root our minimal length trees and polarise our characters in a parsimony analysis; ingroup taxa being Mollusca, Nemertea, Sipuncula, Echiura, Pogonophora, Vestimentifera, Euarthropoda, Onycho-phora, and the groups most commonly regarded as true ‘annelids’, the Clitellata and Polychaeta. We use 13 characters and a total of 33 states. This results in 18 minimal length trees of 23 steps. The consensus tree has the topology (Platyhelminthes (Nemertea (Sipuncula Mollusca (Echiura (Polychaeta (Vestimcntifera Pogonophora) Clitellata (Euarthropoda Onychophora)))))). The name Articulata is applied to the Clitellata, Euarthropoda, Onychophora, Pogonophora, Polychaeta, and Vestimentifera. The Vestimentifera is the sister group to, or more likely a clade within, the frenulate pogonophores, and the name Pogonophora is retained for this group. In half of the 18 minimal length trees, the traditionally formulated Annelida, i.e. Polychaeta and Clitellata, is paraphyletic if the Pogonophora are excluded. In the remaining minimal length trees, a monophyletic Annelida cannot be formulated. The name Annelida should not be used unless relationships within the Articulata are resolved to show it is a monophyletic taxon. The taxon name Articulata, originally formulated to include the Annelida and Arthropoda by Cuvier, is defined as the clade stemming from the first ancestor to show repetition of homologous body structures derived by teloblastic growth with a pygidial growth zone (segmentation) and longitudinal muscles broken into bands. The Articulata is considered, on current evidence, to consist of four monophyletic groups; the Arthropoda, Clitellata, Polychaeta, and Pogonophora, though the latter group may be a clade of polychaetes. If this is shown, the Pogonophora should revert to the original family name Lamellisabellidae Uschakov, 1933. An indented classification reflective of the cladistic pattern is provided. Other recent hypotheses about metazoan systematics arc analysed.     

Transgenic cotton resistant to herbicide bialaphos

Resistance to bialaphos, a non-selective herbicide, was intro duced into cotton through genetic engineering. A gene encoding phosphinothric in acetyltransferase (bar) from Streptomyces hygroscopicus was inserted into elite varieties of cotton through particle bombardment. Based on the marker gene, -glucuronidase (gus) expression, a total of 18 Pima (Gossypium barbadense), 45 DP50 (G. hirsutum L.), 20 Coker 312 (G. hirsutum) and 2 El Dorado (G. hirsutum) transgenic plants were recovered. Integration of the bar gene into cotton genomic DNA was confirmed by Southern blot analysis and gene expression was confirmed by northern blot and enzyme assays. Herbicide (Basta®) tolerance up to 15 000 ppm was demonstrated in greenhouse trials. The newly introduced herbicide tolerance trait is inherited in a Mendelian fashion in the progenies of germline transformants. This study demonstrates the potential for particle bombardment to introduce commerically important genes directly into elite varieties of cotton. This mode of gene transfer can expedite the introduction of transgenic cotton products into world markets     

Variability of DNA Content in Individual Cells of <Emphasis Type="Italic">Bacillus</Emphasis>

THE average content of DNA in Bacillus spores is unaffected by the growth medium and is constant for each species¹. Within the Bacillus group, however, the average amount of DNA per spore varies from species to species¹. A cell of B. cereus contains on average twice as much DNA as the spore and during sporulation this DNA is divided equally between the spore and the sporangium². Estimates^3–5 of genome size vary from 1.3 × 10⁹ to 10 × 10⁹ daltons and the number of genomes per cell from 2 to 4^4–8. Some of these variations may be associated with differences within the cells rather than differences of methodolqgy; spores within a population vary not only in size and shape, but also in their content of stainable chromatin⁹. Moreover, in ‘Renografm’ density gradients¹⁰, spores band within a range of densities. If spores are taken from a narrow part of this range, regrown and rebanded, the original pattern of dispersal occurs, suggesting that spores in the same population normally show variation in density as well as in size (A. I. Aronson, personal communication).     

The Electrical Resistance and Capacitance of the Membranes of Nitella translucens

The resistance and capacitance of the membranes of Nitella translucenshave been measured by direct current and alternating currentmethods. Current of the order of 10^-7 amp. was injected intothe cell by means of a conventional Ag, AgCl_-3N KCl glass microelectrodeinserted into the vacuole of the cell. The change of potentialacross the membrane was recorded by two other internal microelectrodeswhich had been inserted into the cell at known distances fromthe current-injecting electrode. In the direct-current experimentsthe input current was in the form of a square pulse, while sinusoidalcurrents of frequency 25 cycles per second were used in thealternating current experiments. The cell was treated as a shortlength of coaxial cable and from the measurements the followingparameters could be obtained: the space constant (), the membraneresistance (R_m) and the membrane capacitance (C_m). The valuesof R_m ranged from 6.7 to 36 K ohm cm.² (mean of 21.4 K ohm cm.²)and those of ranged from 1.5 to 5.7 cm. (mean of 2.6 cm.).The capacitance value was about I µF cm.^-2 These results are discussed within the framework of our knowledgeof these parameters for other cells, particularly plant cells.The measured electrical resistance is shown to be at least tentimes less than the value estimated from the passive fluxesof the principal ions K, Na, and Cl. It is suggested that thisdiscrepancy, which is usually attributed to non-independentmovement of these ions, could be partially explained on electro-osmoticgrounds. The value of the capacitance is very close to thatwhich is usually obtained for other cell membranes. One exceptionallylow value for Nitella has been quoted in the literature. Thereason for the gross error in this particular measurement isgiven.     

A revision of Nereimyra (Psamathini,Hesionidae, Aciculata,Annelida)

Nereimyra Blainville, 1828 (Psamathini, Hesionidae, Aciculata, Annelida) is revised based on examination of all available types and newly collected specimens. We assessed the phylogeny of Nereimyra in an analysis based on cytochrome oxidase c subunit I (COI), 16S rDNA, 18S rDNA, and 28S rDNA. The genus is delineated to include the three species Nereimyra aphroditoides (Fabricius, 1780), Nereimyra punctata (O.F. Müller, 1776), and Nereimyra woodsholea (Hartman, 1965), which are redescribed. Nereimyra punctata has a characteristic pigmentation, but otherwise there are no clear morphological characters for separating the species. Based on the molecular data we obtained strong support both for the monophyly of Nereimyra and for each of the three included species. Nereimyra punctata and N. woodsholea are sister species, and the Kimura two‐parameter (K2P)‐corrected COI distances between the three species are 16–23%. Syllidia Quatrefages, 1866, is sister group to Nereimyra. Previous uncertainties regarding the type species of the genus are settled to Nereis rosea Fabricius, 1780, junior synonym of N. aphroditoides. A neotype is designated for N. aphroditoides. The distribution of Nereimyra is at present restricted to the Arctic and the boreal parts of the North Atlantic, possibly extending to the Gulf of Mexico on the United States east coast. Records outside this area require verification. Castalia multipapillata Théel, 1879, and Nereimyra alvinae Blake, 1985, are of uncertain affinity and are treated as nomina dubia. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 36–51.