Morphometrical analyses of Secale (Triticeae, Poaceae)

Some fifteen taxa ranked as species or subspecies have generally been recognized within Secale. However, most of these seem impossible to separate on morphology alone. Based on 14 morphological characters considered of diagnostic value and scored on 44 specimens representing most of the taxa a Principal Components Analysis (PCA) was carried out. Limited correlation was found between the characters and consequently the first three principal axes account for only about 60% of the total variation. The PCA shows only a weak separation of annual and perennial taxa. Further analyses mainly of spikelet characters support merging of most of the previously accepted taxa within each of these two groups. A total of three species with five infraspecific taxa are here proposed within the genus and a key is provided to the taxa.     

Synthesis of small molecular weight RNA components during the early stages of sea urchin embryo development

Sea urchin embryos of Psammechinus miliaris contain three major and two minor small molecular weight RNA components called S₁, S₂, S₃ and S₄, S₅, respectively. The synthesis of S₁ and S₂ is initiated in the time interval from 4 to 8 h after fertilization. Hatching and formation of nucleoli take place about 9 – 9.5 h after fertilization and around this time period the synthesis of S₃ is initiated, simultaneously with a qualitative shift in RNA synthesis from predominantly of the heterodisperse type to a synthesis of ribosomal RNA. Shortly after the appearance of nucleoli the synthesis of S₃ is more than twice as fast as S₂. S₁ and S₂ are methylated to about the same extent; S₃ is unmethylated. 60–70% of S₁ and S₂ and 10% of S₃ are localized in the nuclear fraction. The gel electrophoretic mobility of “5” S RNA changes as a result of heat treatment.     

Festuca auriculata in North America

Festuca auriculata Drob., published by Alexeev from one place in Alaska and besides known from the Arctic part of Asia, is shown to occur in several localities in Alaska and the north–western part of Yukon, Canada.     

Taxonomic studies in Dasypyrum (Poaceae)

Dasypyrum (tribe Triticeae) is revised. Two species are recognized: the annual D. villosum (2n = 14) and the perennial D. breviaristatum (2n = 28). The typification of D. villosum is discussed. The combination D. hordeaceum is demonstrated to be based on a later homonym and for that reason a new combination, D. breviaristatum , is made. A key and a map showing the distribution of the species are presented. Interspecific hybridization and the phylogenetic relationships of the genus are discussed.     

Festuca brachyphylla, F. saximontana and related species in North America

American material of Festuca brachyphylla Schult. & Schult., F. saximontana Rydb. and related species was studied. Based on morphology and anatomy F. brachyphylla was separated into three subspecies, two of which are only found in very restricted areas of the southern part of North America, one in California (ssp. breviculmis Frederiksen ssp. nov.) and one in Colorado and neighbouring states (ssp. coloraden–sis Frederiksen ssp. nov.). F. jenseni Gjaerevoll & Ryvarden was found to be the same as F. brachyphylla i.flavida Polun. and the forma level is chosen. F. brachyphylla var. groenlandica Schol. is raised to F. groenlandica (Schol.) Frederiksen. Within F. saximontana a new combination (f. saximontana Rydb. var. purpusiana Frederiksen & Pavlick) is made. American distribution of the taxa studied is mapped. A key including all the taxa has been prepared.     

Evolution of the Zfx and Zfy genes: rates and interdependence between the genes

A phylogenetic analysis of sex-chromosomal zinc-finger genes (Zfx and Zfy) indicates that the genes have not evolved completely independently since their initial separation. The sequence similarities suggest gene conversion in the last exon between the duplicated Y-chromosomal genes Zfy-1 and Zfy-2 in the mouse. There are also indications of conversion (or recombination) between the X- and Y-chromosomal genes in the crab- eating fox and in the mouse. The method for estimating synonymous and nonsynonymous substitutions is modified by incorporating the substitutions in the twofold-degenerate sites in a novel way. The estimates of synonymous substitutions support the generation-time hypothesis in that the obtained rates are higher in mice (by a factor of 4.7) than in humans and higher in the Y-chromosomal genes (by a factor of 1.9) than in the X-chromosomal genes.      

An international network to monitor the structure,composition and dynamics of Amazonian forests (RAINFOR)

Abstract. The Amazon basin is likely to be increasingly affected by environmental changes: higher temperatures, changes in precipitation, CO₂ fertilization and habitat fragmentation. To examine the important ecological and biogeochemical consequences of these changes, we are developing an international network, RAINFOR, which aims to monitor forest biomass and dynamics across Amazonia in a co‐ordinated fashion in order to understand their relationship to soil and climate. The network will focus on sample plots established by independent researchers, some providing data extending back several decades. We will also conduct rapid transect studies of poorly monitored regions. Field expeditions analysed local soil and plant properties in the first phase (2001–2002). Initial results suggest that the network has the potential to reveal much information on the continental‐scale relations between forest and environment. The network will also serve as a forum for discussion between researchers, with the aim of standardising sampling techniques and methodologies that will enable Amazonian forests to be monitored in a coherent manner in the coming decades.     

Low aqueous solubility of 11-cis-retinal limits the rate of pigment formation and dark adaptation in salamander rods

We report experiments designed to test the hypothesis that the aqueous solubility of 11-cis-retinoids plays a significant role in the rate of visual pigment regeneration. Therefore, we have compared the aqueous solubility and the partition coefficients in photoreceptor membranes of native 11-cis-retinal and an analogue retinoid, 11-cis 4-OH retinal, which has a significantly higher solubility in aqueous medium. We have then correlated these parameters with the rates of pigment regeneration and sensitivity recovery that are observed when bleached intact salamander rod photoreceptors are treated with physiological solutions containing these retinoids. We report the following results: (a) 11-cis 4-OH retinal is more soluble in aqueous buffer than 11-cis-retinal. (b) Both 11-cis-retinal and 11-cis 4-OH retinal have extremely high partition coefficients in photoreceptor membranes, though the partition coefficient of 11-cis-retinal is roughly 50-fold greater than that of 11-cis 4-OH retinal. (c) Intact bleached isolated rods treated with solutions containing equimolar amounts of 11-cis-retinal or 11-cis 4-OH retinal form functional visual pigments that promote full recovery of dark current, sensitivity, and response kinetics. However, rods treated with 11-cis 4-OH retinal regenerated on average fivefold faster than rods treated with 11-cis-retinal. (d) Pigment regeneration from recombinant and wild-type opsin in solution is slower when treated with 11-cis 4-OH retinal than with 11-cis-retinal. Based on these observations, we propose a model in which aqueous solubility of cis-retinoids within the photoreceptor cytosol can place a limit on the rate of visual pigment regeneration in vertebrate photoreceptors. We conclude that the cytosolic gap between the plasma membrane and the disk membranes presents a bottleneck for retinoid flux that results in slowed pigment regeneration and dark adaptation in rod photoreceptors.     

Responding to environmental change: plastic responses vary little in a synchronous breeder

The impact of environmental change on animal populations is strongly influenced by the ability of individuals to plastically adjust key life-history events. There is therefore considerable interest in establishing the degree of plasticity in traits and how selection acts on plasticity in natural populations. Breeding time is a key life-history trait that affects fitness and recent studies have found that females vary significantly in their breeding time-environment relationships, with selection often favouring individuals exhibiting stronger plastic responses. In contrast, here, we show that although breeding time in the common guillemot, Uria aalge, is highly plastic at the population level in response to a large-scale environmental cue (the North Atlantic Oscillation, NAO), there is very little between-individual variation-most individuals respond to this climate cue very similarly. We demonstrate strong stabilizing selection against individuals who deviate from the average population-level response to NAO. This species differs significantly from those previously studied in being a colonial breeder, in which reproductive synchrony has a substantial impact on fitness; we suggest that counter selection imposed by a need for synchrony could limit individuals in their response and potential for directional selection to act. This demonstrates the importance of considering the relative costs and benefits of highly plastic responses in assessing the likely response of a population to the environmental change.     

Immune activation in advanced cancer patients treated with recombinant IL-21: multianalyte profiling of serum proteins

Purpose  Recombinant interleukin-21 (rIL-21) is an immune stimulating cytokine recently tested in two Phase 1 trials for immune responsive cancers. A secondary objective of these trials was to characterize pharmacodynamic responses to rIL-21 in patients. Here, we report the effects of systemic rIL-21 on serum markers of immune stimulation. Experimental design  Recombinant IL-21 was administered by intravenous bolus injection at dose levels from 1 to 100 μg/kg using two distinct treatment regimens: thrice weekly (‘3/w’) for 6 weeks; or once daily for five consecutive days followed by nine dose-free days (‘5 + 9’). In the absence of dose limiting toxicity, additional cycles of dosing were initiated immediately following the nine dose-free days. An array of 70 different proteins was profiled in subject serum samples from several time points during the course of the study. Hierarchical clustering analysis was performed on a normalized subset of these data. Results  Systemic administration of rIL-21 affected the serum levels of several cytokines, chemokines, acute-phase proteins and cell adhesion proteins. The magnitude and duration of response were dose dependent for a subset of these biomarkers. The 5 + 9 dosing regimen generally produced cyclic changes that were of greater magnitude, as compared to a more chronic stimulation with the 3/w dosing regimen. Despite these differences, rIL-21 effects on many analytes were similar between regimens when averaged over the time of treatment. Based on similar temporal, between-subject and dose response changes, groups of analytes were identified that exhibited distinct components of the rIL-21-mediated immune activation. Biomarkers indicative of lymphocyte activation (increased IL-16, decreased RANTES), acute phase response (increased CRP, ferritin), myeloid activation (increased MDC, MIP-1 alpha), and leukocyte chemotaxis/trafficking (increased sCAMs, MCP-1) were strongly modulated in subjects treated with rIL-21. Conclusions  Administration of rIL-21 resulted in activation of multiple cell types and immune response pathways. The changes observed in serum proteins were consistent with coincident processes of lymphoid and myeloid cell activation and trafficking, and acute phase response. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.