Nonidentity of Lyt phenotypes and the radiosensitivity of early and late producers of macrophage migration inhibitory factor in reaction to H-2 complex antigens

MIF production induced at different times after intravenous immunization of mice with irradiated allogeneic splenic cells showed different sensitivity to the treatment with anti-Lyt-antibodies and to gamma-irradiation. The "early" MIF producers induced several hours after alloimmunization were sensitive to irradiation at a dose of 500 rad and to the treatment with anti-Lyt-1- and anti-Lyt-2-antibodies and complement, while the "late" MIF producers which appeared 21 days after alloimmunization were resistant to irradiation at doses of 500 and 1500 rad and to the treatment with anti-Lyt-2-antibodies but sensitive to anti-Lyt-1-antibodies. It is supposed that the "early" MIF producers of the Lyt-1+2+ phenotype are immature precursors of T cells which, in contradistinction to the "late" MIF producers of the Lyt-1+2+ phenotype, are activated and produce MIF without proliferation after a twofold contact with antigen.     

Extensive phenotypic diversification coexists with little genetic divergence and a lack of population structure in the White Wagtail subspecies complex (Motacilla alba)

Geographically clustered phenotypes often demonstrate consistent patterns in molecular markers, particularly mitochondrial DNA (mtDNA) traditionally used in phylogeographic studies. However, distinct evolutionary trajectories among traits and markers can lead to their discordance. First, geographic structure in phenotypic traits and nuclear molecular markers can be co‐aligned but inconsistent with mtDNA (mito‐nuclear discordance). Alternatively, phenotypic variation can have little to do with patterns in neither mtDNA nor nuclear markers. Disentangling between these distinct patterns can provide insight into the role of selection, demography and gene flow in population divergence. Here, we examined a previously reported case of strong inconsistency between geographic structure in mtDNA and plumage traits in a widespread polytypic bird species, the White Wagtail (Motacilla alba). We tested whether this pattern is due to mito‐nuclear discordance or discrepancy between morphological evolution and both nuclear and mtDNA markers. We analysed population differentiation and structure across six out of nine commonly recognized subspecies using 17 microsatellite loci and a combination of microsatellites and plumage indices in a comprehensively sampled region of a contact between two subspecies. We did not find support for the mito‐nuclear discordance hypothesis: nuclear markers indicated a subtle signal of genetic clustering only partially consistent with plumage groups, similar to previous findings that relied on mtDNA. We discuss evolutionary factors that could have shaped the intricate patterns of phenotypic diversification in the White wagtail and the role that repeated selection on plumage ‘hotspots’ and hybridization may have played.     

Exploring Cryptic Diversity and Distribution Patterns in the Mallomonas kalinae/rasilis Species Complex with a Description of a New Taxon—Mallomonas furtiva sp. nov.

A complex of closely related Mallomonas taxa belonging to the section Papillosae, M. kalinae ?ezá?ová and M. rasilis Dürrschmidt, has been studied in detail by molecular and morphometric methods. Our investigations uncovered the existence of a new species found in water bodies in Vietnam, which we describe here as Mallomonas furtiva sp. nov. This taxon is morphologically very similar to M. kalinae , from which it differs by minute, but statistically significant morphological differences on the structure of silica scales. Indeed, the principal component analysis of morphological traits measured on silica scales significantly separates all three species in the complex. Mallomonas kalinae and M . furtiva differ by number of papillae on the shield and the dome, as well as by the scale sizes. Likewise, Mallomonas rasilis and M. furtiva are primarily differentiated by the absence of submarginal anterior ribs on silica scales of the former species. Phylogenetic analyses showed that Mallomonas furtiva is closely related to M . kalinae , with which it formed a highly supported lineage. Distribution patterns of all three studied taxa are further discussed.     

Dendroclimatological potential of three juniper species from the Turkestan range,northwestern Pamir-Alay Mountains,Uzbekistan

Key message

Intensity and magnitude of the growth-climate relationship depends on juniper species and sites. Juniperus seravschanica at low elevations shows highest potential for April–September drought reconstruction in the Turkestan range (Pamir-Alay), Uzbekistan.

Abstract

We present a detailed dendroclimatological study of three juniper species, Juniperus seravschanica Kom., Juniperus semiglobosa Regel and Juniperus turkistanica Kom., sampled at six sites of different elevation (2100–2700 m a.s.l.), exposition (west and south) and steepness (10°–30°) in the Zaamin National Park, Turkestan range, Pamir-Alay mountain system in eastern Uzbekistan. Simple correlation statistics and redundancy analyses were applied to detect species- and site-specific climate responses during the twentieth century, which were additionally investigated in the high-frequency domain by identifying extreme growth years. Our results show that tree-ring formation of J. seravschanica at our low-elevation site is strongly limited by April to September drought conditions, while J. semiglobosa inherits a weak and variable climate response with respect to elevation. J. turkistanica growth at high altitudes is positively associated with warm spring and summer temperatures. Species-specific growth extremes are triggered by incoming air masses from the Atlantic and Arctic, highlighting the connection of synoptic climate regimes across Eurasia. From a dendroclimatic perspective, J. seravschanica exhibits a high potential for reconstructing past drought and pluvials, but under sustained temperature rise also J. semiglobosa will likely increase its sensitivity to drought. Moreover, J. turkistanica at its distribution limit at the tree line is a suitable proxy of summer temperature. Our findings clearly demonstrate that a careful selection of the site, overall topography and elevation as well as the different juniper species are important for successfully reconstructing past climate in Uzbekistan.

     

An explanation for the narrow carbohydrate substrate specificity of adenine phosphoribosyltransferase from Thermus thermophilus from the model of the enzyme,substrate, and magnesium cation cofactor complex

Communicated by Ramaswamy H. Sarma     

Effect of stem cell inhibition factor and macrophage inhibition factor on mouse spleen cell exocolonization and migration]

The migration activity of the spleen cells from intact mice is inhibited by the stem cell inhibitory factor (SCIF) released by lymphocytes treated with antilymphocytic globulin. The degree of the migration inhibition is proportional to the activity of SCIF in the colony-formation inhibition. The macrophage-migration inhibitory factor (MIF), obtained in the H-2 system exhibited a stimulating effect on the colony formation in mice when used in vitro for the treatment of bone marrow transplants. This activity of MIF corresponds to its migration-inhibitory effect on the spleen cells. Incubation of the bone marrow cells with MIF for 30 minutes is more effective than the 2-hour treatment. The observed effects are interpreted as an indication of non-identity of SCIF and MIF.     

Insight into the Structure of the “Unstructured” Tau Protein

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Comparative molecular phylogeny and evolution of sex chromosome DNA sequences in the family Canidae (Mammalia: Carnivora)

To investigate the molecular phylogeny and evolution of the family Canidae, nucleotide sequences of the zinc-finger-protein gene on the Y chromosome (ZFY, 924-1146 bp) and its homologous gene on the X chromosome (ZFX, 834-839 bp) for twelve canid species were determined. The phylogenetic relationships among species reconstructed by the paternal ZFY sequences closely agreed with those by mtDNA and autosomal DNA trees in previous reports, and strongly supported the phylogenetic affinity between the wolf-like canids clade and the South American canids clade. However, the branching order of some species differed between phylogenies of ZFY and ZFX genes: Cuon alpinus and Canis mesomelas were included in the wolf-like canid clades in the ZFY tree, whereas both species were clustered in a group of Chrysocyon brachyurus and Speothos venaticus in the ZFX tree. The topology difference between ZFY and ZFX trees may have resulted from the two-times higher substitution rate of the former than the latter, which was clarified in the present study. In addition, two types of transposable element sequence (SINE-I and SINE-II) were found to occur in the ZFY final intron of the twelve canid species examined. Because the SINE-I sequences were shared by all the species, they may have been inserted into the ZFY of the common ancestor before species radiation in Canidae. By contract, SINE-II found in only Canis aureus could have been inserted into ZFY independently after the speciation. The molecular diversity of SINE sequences of Canidae reflects evolutionary history of the species radiation.     

Fe(II) phthalocyanine catalyzed oxidation of dGMP by molecular oxygen

We show that iron(II)-phthalocyanines are able to catalyze guanosine oxidation by molecular oxygen in the presence of reducing agents such as ascorbic acid and 2-mercaptoethanol. The products of 5′-monophosphate-2′-deoxyguanosine (dGMP) oxidation were directly analyzed using the HPLC-ESI/MS method. The main oxidation products were 5′-phospho-2′-deoxy-8-oxo-7,8-dihydroguanine and the 1,N2-glyoxal adduct of the 5′-monophosphate-2′-deoxyguanosine.