Are the landscape‐level drivers of water column and surface sediment diatoms different?

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Genotype × region and genotype × production level interactions in Holstein cows

The identification of the presence of genotype by environment interaction effects on important traits in Holstein cattle allows for the use of international genetic evaluations and a more efficient design of regional genetic evaluation programmes. The aim of this study was to determine the genotype × environment interaction effects in Chilean Holstein dairy cattle through the analysis of records corresponding to calvings between 1998 and 2015. Herds were classified in the central and southern regions of Chile based on herd location as well as by high and low levels of production environments based on the fat plus protein yield averages per herd within each region. The central region has a Mediterranean climate and a confined production system while the southern region has a humid temperate climate and a production system based on grazing with supplementation. Traits studied were milk yield (MY), fat yield (FY), protein yield (PY), fat content (FC) and protein content (PC) by lactation, age at first calving (AFC) and calving interval (CI). Several four-trait mixed animal models were applied to environmental category data as different traits, which included herd-year-calving season (herd-year-birth season for AFC) and lactation number as fixed effects, and animal additive genetic, sire-herd, permanent environment and residual effects as random effects. Genetic correlations (r_g) for MY, FY, FC, PC and CI were found to decrease as differences between environmental categories increased. The r_g between the most extreme environmental categories considered in this study for AFC (0.26) was the only one found statistically lower than 0.60. Genetic correlation values statistically lower than 0.80 (P < 0.05) were observed for AFC, CI, MY, FY and PY between some environmental categories. If separate genetic evaluations are adopted as practical criteria when the value of r_g is lower than 0.60, the consequence of improving a multi-trait economic breeding objective in this population is likely to be small unless extreme environmental categories are considered. However, a moderate decrease in selection response and re-ranking of selection candidates is expected for AFC, CI and yield traits when selection is performed in different environmental conditions. Genotype × environment interaction effects involving production systems in a Mediterranean climate and confinement vs. Temperate Oceanic climate and grazing with supplementation, and between two fat plus protein yield level categories within each environment, were at most moderate for the studied traits.     

The energy-yielding reactions of Peptococcus prévotii,their behaviour on starvation and the role and regulation of threonine dehydratase

The principal energy-yielding reactions of the strict anaerobe Peptococcus prévotii comprised the fermentation of l-serine and l-threonine via the enzymes threonine dehydratase, thioclastic enzyme, phosphotransacetylase and acetate kinase.Threonine dehydratase was purified 700-fold and shown to require pyridoxal 5-phosphate as co-enzyme, and a reducing agent for optimum activity. The ratio of threonine and serine dehydratase activities was unaltered during purification. The optimum pH was 8.5 to 9.5 and isoleucine did not inhibit.Lineweaver-Burk plots were linear at l-threonine concentrations above 1.35 mM and the K _m for threonine was 2.5 mM and for serine 29 mM. Below this concentration co-operativity occurred which was not nullified by individual adenine nucleotides: Hill plots were biphasic.However, the enzyme was controlled by the adenylate energy charge in a novel manner; only at very low threonine concentrations (<1 mM) was control manifest, when a high energy charge inhibited and a low energy charge stimulated activity.During starvation for 33 hrs in phosphate buffer, pH 6.8, viability fell to zero but, of the enzymes of the energy-generating sequence, only the total units and specific activity of threonine dehydratase decreased (by 35%), which was insufficient to explain the loss of ability to generate ATP.     

Do ploidy level and nuclear genome size and latitude of origin modify the expression of <Emphasis Type="Italic">Phragmites australis</Emphasis> traits and interactions with herbivores?

We studied the relationship between genome size and ploidy level variation and plant traits for the reed grass Phragmites australis. Using a common garden approach on a global collection of populations in Aarhus, Denmark, we investigated the influence of monoploid genome size and ploidy level on the expression of P. australis growth, nutrition and herbivore-defense traits and whether monoploid genome size and ploidy level play different roles in plant trait expression. We found that both monoploid genome size and latitude of origin contributed to variation in traits that we studied for P. australis, with latitude of origin being generally a better predictor of trait values and that ploidy level and its interaction with monoploid genome size and latitude of origin also contributed to trait variation. We also found that for four traits, tetraploids and octoploids had different relationships with the monoploid genome size. While for tetraploids stem height and leaf water content showed a positive relationship with monoploid genome size, octoploids had a negative relationship with monoploid genome size for stem height and no relationship for leaf water content. As genome size within octoploids increased, the number of aphids colonizing leaves decreased, whereas for tetraploids there was a quadratic, though non-significant, relationship. Generally we found that tetraploids were taller, chemically better defended, had a greater number of stems, higher leaf water content, and supported more aphids than octoploids. Our results suggest trade-offs among plant traits mediated by genome size and ploidy with respect to fitness and defense. We also found that the latitude of plant origin is a significant determinant of trait expression suggesting local adaptation. Global climate change may favor some genome size and ploidy variants that can tolerate stressful environments due to greater phenotypic plasticity and to fitness traits that vary with cytotype which may lead to changes in population genome sizes and/or ploidy structure, particularly at species’ range limits.     

The relationships between EEG θ and β oscillations and the level of creativity

The interrelations between the level of creativity and both the baseline power and event-related desynchronization/synchronization (ED/ES) of θ and β rhythms during a figural creative task (Torrance’s “Incomplete Figures” test) were studied under the conditions of different motivations. A higher motivation was caused by instruction “to create most unique images” as opposed to the instruction “to create images.” The subjects, right-handed students (14 males and 14 females), were divided into two groups with high and low originality scores (OSs). The baseline power and the ED/ES of the θ₂ and β rhythms of the subjects were found to depend on the level of creativity and person’s sex only in response to the instruction “to create images.” Male subjects with higher OSs differed from those with lower OSs in a stronger ED of the θ₂ rhythm in temporal-parietal-occipital brain regions, whereas these differences were absent in female subjects. Task performance was accompanied by ED of β₁ rhythm in men with higher OSs, whereas in women with higher OSs, ES was recorded in the same band. Only in women with high OSs did analysis of β_{1, 2} reference power show a higher β₁ power in the caudal hemispheric regions as compared to the frontal ones. High-OS subjects of different genders also differed in the lateral patterns of activity in the electrode loci Fp_1/2 (β₁) and Fp_1/2, F_7/8 (β₂). Our results suggest that a high level of creativity in men and women is related to sex-dependent specific patterns of frontal-occipital and lateral activities of θ and β rhythm oscillators in the brain cortex.     

Serine hydroxymethyltransferase and threonine aldolase: are they identical?

Serine hydroxymethyltransferase, a pyridoxal phosphate-dependent enzyme, catalyses the interconversion of serine and glycine, both of which are major sources of one-carbon units necessary for the synthesis of purine, thymidylate, methionine, and so on. Threonine aldolase catalyzes the pyridoxal phosphate-dependent, reversible reaction between threonine and acetaldehyde plus glycine. No extensive studies have been carried out on threonine aldolase in animal tissues, and it has long been believed that serine hydroxymethyltransferase and threonine aldolase are the same, i.e. one entity. This is based on the finding that rabbit liver serine hydroxymethyltransferase possesses some threonine aldolase activity. Recently, however, many kinds of threonine aldolase and corresponding genes were isolated from micro-organisms, and these enzymes were shown to be distinct from serine hydroxymethyltransferase. The experiments with isolated hepatocytes and cell-free extracts from various animals revealed that threonine is degraded mainly through the pathway initiated by threonine 3-dehydrogenase, and there is little or no contribution by threonine aldolase. Thus, although serine hydroxymethyltransferase from some mammalian livers exhibits a low threonine aldolase activity, the two enzymes are distinct from each other and mammals lack the "genuine" threonine aldolase.     

IRE1α disruption causes histological abnormality of exocrine tissues, increase of blood glucose level, and decrease of serum immunoglobulin level

Accumulation of unfolded proteins in the endoplasmic reticulum (ER) causes ER stress. As a cellular adaptive response to ER stress, unfolded protein response (UPR) activates molecules for the quality control of ER proteins. One enzyme that plays an important role in UPR is Inositol Requiring Enzyme-1 (IRE1), which is highly conserved from yeast to humans. In particular, mammalian IRE1α activates X-box-binding protein 1 (XBP1) by unconventional splicing of XBP1 mRNA during ER stress. From analysis of knockout mice, both IRE1α and XBP1 have been shown to be essential for development and that XBP1 is necessary for the secretory machinery of exocrine glands, plasma cell differentiation, and hepatic lipogenesis. However, the essentiality of IRE1α in specific organs and tissues remains incompletely understood. Here, we analyzed the phenotype of IRE1α conditional knockout mice and found that IRE1α-deficient mice exhibit mild hypoinsulinemia, hyperglycemia, and a low-weight trend. Moreover, IRE1α disruption causes histological abnormality of the pancreatic acinar and salivary serous tissues and decrease of serum level of immunoglobulin produced in the plasma cells, but not dysfunction of liver. Comparison of this report with previous reports regarding XBP1 conditional knockout mice might provide some clues for the discovery of the novel functions of IRE1α and XBP1.     

Characteristics of photosynthesis in maize leaves (С<Subscript>4</Subscript> plants) upon changes in the level of illuminance and nitrate nutrition

We studied assimilation of ¹⁴СО₂ and distribution of ¹⁴С among the products of 3-min-long photosynthesis of maize (Zea mays L.) leaves. The day before the experiment, half of the plants were fertilized with Ca(NO₃)₂ (1 g/L of water) at a rate of 6 L/m². Five days before the experiment, some plants were shaded for adaptation (illuminance was reduced by 50%). On the day of the experiment (before the application of ¹⁴СО₂), several shaded plants were exposed to direct sunlight for 3 min, and some plants grown at full light (light plants) were shaded for 3 min (illuminance of 50%). Unfertilized plants adapted for 5 days to shading showed photosynthesis of 75.9% of control level (full light). If light plants were transferred to shading for 3 min, their photosynthesis decreased to 42.1%. In plants shaded for 5 days and then transferred to full light, photosynthesis in 3 min was 96.3% of control level. At full light, fertilization with nitrate boosted photosynthesis to 132.6% as compared with control material, but photosynthesis decreased to 43.5 and 65.4% of control level in plants shaded for 5 days and those shaded for 3 min, respectively. At the same time, the plants shaded for 5 days and then exposed for 3 min to full light restored photosynthesis to almost control level (95.5%). Analysis of ¹⁴С distribution among the products of 3-min-long photosynthesis showed that, the same as in C₃ plants, a decrease in illuminance (especially a sudden one) in maize reduced the ratio between labeled sucrose and hexoses and elevates incorporation of ¹⁴С into malate, which indicated that its consumption in bundle sheath cells was suppressed. A decrease in the ratio between labeled sucrose and hexoses became more pronounced under the influence of nitrates with this effect also occurring in transport products of photosynthesis (20 cm below ¹⁴С-providing leaf area). In plants fertilized with nitrates, radioactivity of sucrose (% of radioactivity of soluble compounds) decreased in all the types of illumination. When illuminance was suddenly reduced for 3 min, incorporation of ¹⁴С into sucrose was 21.5 against 51.2% in light plants, and radioactivity of aspartate and malate sharply rose to 13.7 and 26.1% (against 2.1 and 8.9% in control material). Incorporation of ¹⁴С into compounds of glycolate pathway was low (less than 2.5%), but it was somewhat greater in nitrate plants. We concluded that the same mechanism of interaction between stomatal apparatus of leaf epidermis, invertase of mesophyll apoplast, and photosynthetic metabolism of carbon with electron flux via electron transport chain in chloroplasts of bundle sheath cells, which governs the rate of photosynthesis and assimilate export from the leaf but is triggered by the extent of consumption in the bundle sheath cells of C₄ acids produced in the mesophyll operates in C₄ plants (the same as in C₃ plants).     

Influence of chronic exposure to low doses of γ-radiation and <Superscript>90</Superscript>Sr on the level of DNA breaks and cell sensitivity to hydrogen peroxide in the mouse spleen

Using comet assay, a statistically significant increase (p < 0.05) in the level of DNA breaks in spleen cells was revealed in male CBA/lac mice exposed to γ-radiation (1.7 mGy/day) or ⁹⁰Sr (150–250 Bq/day) for 210 days. The level of DNA breaks also increased under combined exposure to both γ-radiation and ⁹⁰Sr (p < 0.05), but to a lesser degree than under exposure to each of these factors alone. Upon additional in vitro treatment of spleen cells with hydrogen peroxide, the relative increase in the level of DNA breaks was smaller in cells of irradiated mice than in the control. The ratio of the level of DNA breaks after hydrogen peroxide treatment to that before this treatment in control mice was 4.2 ± 0.9, compared to 1.4 ± 0.6 in γ-irradiated mice, 1.9 ± 0.8 in ⁹⁰Sr-irradiated mice, and 2.3 ± 0.8 in mice exposed to both γ- and ⁹⁰Sr-irradiation.     

Association of HL-A antigens andβ 2-microglobulin at the cellular and molecular level

Surfaces of cultured human lymphoid cells RPMI 1788, RPMI 4098, RPMI 8866, Raji, and WI-L2 were found to contain bothβ ₂-microglobulin (β ₂-μ) and HL-A determinants when tested by direct complement-dependent cytotoxicity andquantitative absorption with different cytotoxic antiβ ₂-μ antisera and specific HL-A alloantisera. The same antigenic specificities were found in 3M KCl extracts of these cultured cells with a sensitiveβ ₂-μ radioimmunoassay and an HL-A antigen blocking assay. Daudi cells provided a contrast, since noβ ₂-μ or HL-A determinants were found on their surfaces or in 3 M KCl extracts prepared from them. Results from specific antibody blocking tests suggest a close association betweenβ ₂-μ and HL-A determinants on plasma membranes of cultured human lymphoid cells. A solid state immunoadsorbent containing antiβ ₂-μ antibodies effectively removed all detectable HL-A antigenic activity from some 3M KCl extracts of cultured human lymphoid cells as well as from some sera. Adsorption of HL-A antigens to these immunoadsorbents was specific since it was blocked only by prior addition ofβ ₂-μ. Once on the antiβ ₂-μ immunoadsorbents, HL-A antigens still reacted specifically with HL-A alloantibodies in quantitative absorption experiments. HL-A antigens andβ ₂-μ could be eluted from antiβ ₂-μ immunoadsorbents with a variety of chaotropic reagents and detergents, but thus far potassium bromide and sodium dodecyl sulfate (SDS) appear to be the most effective. SDS-PAGE of these eluates indicated that HL-A antigens were considerably purified by adsorption to antiβ ₂-μ immunoadsorbents and that two major molecular size fragments were distinguishable, i.e., ∼33,000 for HL-A and ∼ 12,000 forβ ₂-μ.     

Effects of ligands of α<Superscript>2</Superscript>-adrenoceptors on mRNA level of apoptotic proteins in developing rat brain

The effects of antagonist of α²-adrenoceptors yohimbine and their agonist clonidine on Bax and Bcl-X _L mRNA levels in neonatal rat brain were studied. Yohimbine decreased Bax mRNA level in the cerebellum, increased the ratio between Bcl-X _L and Bax mRNA levels in the cerebellum, cortex, and hippocampus, and increased Bcl-X _L mRNA level in the cortex and hippocampus of 6-day-old-rat pups 24 h after injection. Administration of clonidine 20 min after yohimbine administration abolished its effect on Bcl-X_L mRNA level in the hippocampus. The data obtained indicate that the blockade of α²-adrenoceptors induces antiapoptotic changes in the developing rat brain, some of which can be abolished after coadministration with the agonist of these receptors.     

Does multi‐level environmental filtering determine the functional and phylogenetic composition of wild bee species assemblages?

A central goal in ecology is to develop theories that explain the diversity and distribution of species. The evolutionary history of species and their functional traits may provide mechanistic links between community assembly and the environment. Such links may be hierarchically structured such that the strength of environmental filtering decreases in a step‐wise manner from regional conditions through landscape heterogeneity to local habitat conditions. We sampled the wild bee species assemblages in power‐line strips transecting forests in south‐eastern Norway. We used altitude, landscape diversity surrounding sites and plant species composition, together with total plant cover as proxies for regional, landscape and local environmental filters, respectively. The species richness and abundance of wild bees decreased with altitude. The reduction in species richness and abundance was accompanied by a phylogenetic clustering of wild bee individuals. Furthermore, regional filters followed by local filters best explained the structure of the functional species composition. Sites at high altitudes and sites with Ericaceae‐dominated plant communities tended to have larger bees and a higher proportion of social and spring‐emerging bees. When Bombus species were excluded from the analysis, the proportion of pollen specialists increased with the dominance of Ericaceae. Furthermore, we also found that the taxonomic, phylogenetic and functional compositional turnover between sites was higher in the northern region than in the southern part of the study region. Altogether, these results suggest that regional filters drive the species richness and abundance in trait‐groups whereas local filters have more descrete sorting effects. We conclude that the model of multi‐level environmental filters provides a good conceptual model for community ecology. We suggest that future studies should focus on the relationship between the biogeographical history of species and their current distribution, and on the assumption that closely related species do indeed compete more intensely than distantly related species.     

Gender differences in parameters of lipid metabolism and of level of antioxidants in groups of juveniles—the Even and the Europeans

There was performed a comparative evaluation of the mean values of lipid metabolism parameters in youths and girls of the indigenous population (the Even), of the coming population of the north of Irkutsk province, and of the province center (the Europeoids). Gender differences in HDLP have been revealed in adolescents of the coming population, in the glutathione status and the content of liposoluble vitamins in the Even and coming adolescents and in retinol concentration in the province center adolescents. Adaptive changes in the ROS system were found in the Even girls (the higher α-tocopherol and GSH concentrations and the GSH/GSSG ratio as well as a decrease of GSSG relative to the Even youths and the coming population girls, an increase of α-tocopherol relatively to the coming population Europeoids) and youth of the coming population (the higher GSH content and the GSH/GSSG parameter relatively to the Even youths).     

Export of β-1,3-glucanase from mutant rice cells rechallenged and stressed with lysine plus threonine

Mutant rice cells (Oryza sativa L.) grown in liquid suspension cultures exported greater quantities of protein and -glucanases than controls. These mutants were isolated from anther calli resistant to 1 mM lysine plus threonine (LT), regenerated and reestablished as cell suspension cultures from seeds. Cellular protein levels are genetically conditioned, and the levels of extracellular proteins and enzyme activities are inversely related to that of the cellular portions. The rechallenge of cells with 1 mM LT inhibited the expression of both -1,3-glucanases and -1,4-glucosidases but had no significant effect upon the levels of chitinase activity. Mutant cells were more sensitive than controls to stress caused by exogenous LT. In general, under exogenous LT stress the mutant/control ratio for extracellular glucanases increased as the assay conditions were changed from a basic to an acidic pH. The specific activity of glucanases was highest in media and lowest in cells. Both the mutant and control cells exported -glucanases into the suspension medium, but the level of activity in media was greater in that in which the mutant was suspended. The export was probably modulated by the internal protein levels which were highest in mutant cells without LT. Seedlings from mutants with enhanced lysine also had enhanced acidic -glucanase activity.     

Fetal haemoglobin level—effect of gender,age and haemoglobin disorders

Fetal haemoglobin (HbF) level shows significant variations in health and disease states. In this study we investigated Hb F level in 75 cord bloods, 1266 healthy individuals, 1582 Hb S heterozygotes, 464 sickle cell anaemia, 93 Hb S/2-thalassemia and 65 -thalassemia major patients. The age range of the study groups varied from newborn to over 60 years of age. Hb F level was measured by an alkali denaturation procedure and by radial immunodiffusion. The ratio of the level of G-globin chains to the level of A-globin chains (G/A) was determined in the patients group by high performance liquid chromatography. The Hb F level was significantly higher in the sickle cell anaemia and -thalassemia major patients compared to the Hb S heterozygotes and the normal individuals. Within each group Hb F level was higher in the female population compared to the age-matched male groups. This difference was statistically significant (P<0.05) in the sickle cell disease patients and -thalassemia major patients but not in the normal individuals. After the age of 30 years, the difference in the value of Hb F in the male and female population become more apparent (P<0.05) in the sickle cell disease and -thalassaemia major patients. No statistically significant sex differences were found in the G/Aratio in the patient groups, and the range of G/Aratio in the patients groups were similar to those in the control group.The results showed that age, sex and genetic disorders of haemoglobin are factors that affect Hb F level and indicate the possible involvement of an X-linked factor in control of Hb F production.     

Chromosome number and DNA ploidy level reports of vascular plants — 4

Section Botany

Chromosome number and DNA ploidy level reports of vascular plants — 4     

Dependence of nitrogen- and phosphorus-regulation of β-lactam antibiotic production byStreptomyces clavuligerus on aeration level

Interference with -lactam production inStreptomyces clavuligerus by ammonium and phosphate ions, normally observed with optimum levels of aeration, was eliminated by restriction of the air supply. Under such a restriction, ammonium slightly stimulated and phosphate markedly stimulated -lactam antibiotic production. These are rare examples of regulation reversal by an environmental modification.