Motivation and placebos: do different mechanisms occur in different contexts?

This paper challenges the common assumption that the mechanisms underlying short-term placebo paradigms (where there is no motivation for health improvement) and long-term placebo paradigms (where patients value improvement in their health) are the same. Three types of motivational theory are reviewed: (i) classical placebo motivation theory that the placebo response results from the desire for therapeutic improvement; (ii) goal activation model that expectancy-driven placebo responses are enhanced when the placebo response satisfies an activated goal; and (iii) motivational concordance model that the placebo response is the consequence of concordance between the placebo ritual and significant intrinsic motives. It is suggested that current data are consistent with the following theory: response expectancy, conditioning and goal activation are responsible for short-term placebo effects but long-term therapeutic change is achieved through the effects of goal satisfaction and affect on the inflammatory response system and hypothalamic-pituitary-adrenal axis. Empirical predictions of this new theory are outlined, including ways in which placebo effects can be combined with other psychologically mediated effects on short-term and long-term psychological and physiological state.     

Are different proteins synthesized in distinct domains in a neuron?

Are different messenger RNA species translated in distinct, limited domains within a cell? For the particular case of the giant R2 neuron from Aplysia californica an answer to this question is possible for the more abundantly synthesized proteins. After brief labeling with 35S-methionine, the R2 neuron soma was frozen and divided into two or three parts. The newly synthesized proteins were analyzed following two-dimensional polyacrylamide gel electrophoresis. No evidence for limited domains of synthesis for 26 abundantly synthesized polypeptides in the R2 neuron was found.     

Isoprenoid biosynthesis in bacteria: Two different pathways?

Abstract The biosynthesis of isopentenylpyrophosphate, a central intermediate of isoprenoid formation, was investigated in six different bacterial organisms. Cell-free extracts of Myxococcus fulvus, Staphylococcus carnosus, Lactobacillus plantarum and Halobacterium cutirubrum converted [¹⁴C]acetyl-CoA or [¹⁴C]hydroxymethylglutaryl-CoA to [¹⁴C]mevalonic acid. Furthermore, [¹⁴C]mevalonic acid, [¹⁴C]mevalonate-5-phosphate and [¹⁴C]mevalonate-5-pyrophosphate were metabolized to [¹⁴C]isopentenylpyrophosphate in bacteria. In contrast, no intermediates of this reaction sequence could be detected using cell-free extracts of Zymomonas mobilis and Escherichia coli . These results indicate that at least two different pathways for the biosynthesis of isopentenylpyrophosphate are present in bacteria.     

Palaeoecology: different dinosaur ecologies in deep time?

Do dinosaurs from the Moroccan Kem Kem formation provide evidence for an?ecosystem dramatically different from anything seen today? More likely the common palaeontological problem of time-averaging has had a part to play.     

Is tree diversity different in the Southern Hemisphere?

Questions: Is tree diversity higher in the southern hemisphere? Are latitudinal asymmetries in diversity sensitive to sampling effects? Location: 198 forested locales worldwide. Methods: I re‐analysed the Gentry database, which I augmented with an additional survey from New Zealand. Data were used to test whether latitudinal declines in tree diversity differ between the northern and southern hemispheres. Data were also used to test whether hemispheric asymmetries in diversity are sensitive to sampling effects, or geographic variation in tree densities. Results: Area‐based measurements of species diversity are higher in the southern hemisphere. However, southern forests house denser plant populations. After controlling for geographic variation in tree densities, diversity patterns reverse, indicating tree diversity is higher in the northern hemisphere. Conclusions: Latitudinal changes in tree diversity differ between hemispheres. However, the nature of hemispherical asymmetries in species diversity hinges on how diversity is defined, illustrating how different definitions of diversity can yield strikingly different solutions to common ecological problems.     

Could different environmental conditions select for different flight characteristics in sexual and asexual parasitoid Venturia canescens?

In the parasitoid Venturia canescens Gravenhorst (Hymenoptera: Ichneumonidae), asexual and sexual wasps coexist in the field in the Mediterranean basin, but only the asexual strain is present indoors. The sexual strain dominates outdoors despite the demographic costs associated with the production of males and mate location. The present study tests whether females of the sexual and asexual strains of V. canescens differ in flight characteristics in line with the differences of their preferred habitats and enquires whether these differences might contribute to the persistence of sexually reproducing individuals in the vicinity of asexual counterparts. The results show that sexual female wasps are smaller than their asexual counterparts. The size of wasps has a strong influence on flight parameters, with larger animals generally being better fliers. In wasps of approximately the same size, sexual wasps fly faster than their asexual counterparts under experimental laboratory conditions, in terms of both the average speed over the observation period as well as the longest single flight. Sexual wasps also perform fewer flights to cover the same distance. Sexual wasps have higher wing loading than asexual ones of the same size, which could have contributed to the observed differences in speed between individuals of both reproductive modes. There are no significant differences between the two reproductive modes in the parameters related to the distance traversed or the time spent in flight. This study shows clear differences in the flight behaviour of sexual and asexual V. canescens. Together with previous results, this finding suggests differential adaptations to their preferred habitats. These differences might ease the competition between modes of reproduction through niche and habitat differentiation and might help to explain their coexistence on a geographical scale.     

Poly-β-hydroxybutyrate accumulation in bacterial consortia from different environments

The aim of the present study was to examine soil samples from various vegetation zones in terms of physicochemical properties, microbial communities, and isolation and identification (by polymerase chain reaction and transmission electron microscopy) of bacteria producing poly-β-hydroxybutyrates (PHBs). Soil samples were analysed originating from zones with heterogeneous environmental conditions from the Romanian Carpathian Mountains (mountain zone with alpine meadow, karstic zone with limestone meadow, hill zone with xerophilous meadow, and flood plain zone with hygrophilic meadow). Different bacterial groups involved in the nitrogen cycle (aerobic mesophilic heterotrophs, ammonifiers, denitrifiers, nitrifiers, and free nitrogen-fixing bacteria from Azotobacter genus) were analysed. Soil biological quality was assessed by the bacterial indicator of soil quality, which varied between 4.3 and 4.7. A colony polymerase chain reaction technique was used for screening PHB producers. With different primers, specific bands were obtained in all the soil samples. Some wild types of Azotobacter species were isolated from the 4 studied sites. Biodegradable polymers of PHB were assessed by negative staining in transmission electron microscopy. The maximum PHB granules density was obtained in the strains isolated from the xerophilous meadow (10-18 granules/cell), which was the most stressful environment from all the studied sites, as the physicochemical and microbiological tests proved.     

Disturbance and stress: different meanings in ecological dynamics?

There is an increasing frequency of papers addressing disturbance and stress in ecology without clear delimitation of their meaning. Some authors use the terms disturbance and stress exclusively as impacts, while others use them for the entire process, including both causes and effects. In some studies, the disturbance is considered as a result of a temporary impact, which is positive for the ecosystem, while stress is a negative, debilitating impact. By developing and testing simple theoretical models, the authors propose to differentiate disturbance and stress by frequency. If the frequency of the event enables the variable to reach a dynamic equilibrium which might be exhibited without this event, then the event (plus its responses) is a disturbance for the system. If frequency prevents the variable’s return to similar pre-event dynamics and drives or shifts it to a new trajectory, then we are facing stress. The authors propose that changes triggered by the given stimuli can be evaluated on an absolute scale, therefore, direction of change of the variable must not be used to choose one term or the other, i.e. to choose between stress and disturbance.     

Fcγ receptors exhibit different phagocytosis potential in human neutrophils

In neutrophils, two receptors for IgG antibodies, namely FcγRIIA and FcγRIIIB are constitutively expressed, and a third one, FcγRI, can be upregulated by interferon-γ. Whether FcγRIIIB is capable of triggering phagocytosis by itself is still controversial. The main role of FcγRI has not been clearly established in these cells. To address this problem, neutrophils were treated with interferon-γ, and then phagocytosis mediated by each type of Fcγ receptor was evaluated by flow cytometry. FcγRIIA was the most efficient receptor for phagocytosis. FcγRIIIB could mediate phagocytosis but much less efficiently than FcγRIIA. Both FcγRIIA- and FcγRIIIB-mediated phagocytosis were blocked by inhibitors of Src family kinases, Syk, PI 3-K, and ERK. In contrast, interferon-γ-induced FcγRI was not able to mediate phagocytosis. Also, FcγRI did not activate ERK in the nucleus, but was however able to stimulate an efficient calcium rise. These data show that different neutrophil Fcγ receptors possess different phagocytosis capabilities: FcγRIIA and FcγRIIIB, but not FcγRI, promote phagocytosis.     

Statins in cardiometabolic disease: what makes pitavastatin different?

The term cardiometabolic disease encompasses a range of lifestyle-related conditions, including Metabolic syndrome (MetS) and type 2 diabetes (T2D), that are characterized by different combinations of cardiovascular (CV) risk factors, including dyslipidemia, abdominal obesity, hypertension, hyperglycemia/insulin resistance, and vascular inflammation. These risk factors individually and interdependently increase the risk of CV and cerebrovascular events, and represent one of the biggest health challenges worldwide today. CV diseases account for almost 50% of all deaths in Europe and around 30% of all deaths worldwide. Furthermore, the risk of CV death is increased twofold to fourfold in people with T2D. Whilst the clinical management of CV disease has improved in Western Europe, the pandemic of obesity and T2D reduces the impact of these gains. This, together with the growing, aging population, means the number of CV deaths is predicted to increase from 17.1 million worldwide in 2004 to 23.6 million in 2030. The recommended treatment for MetS is lifestyle change followed by treatment for the individual risk factors. Numerous studies have shown that lowering low-density lipoprotein-cholesterol (LDL-C) levels using statins can significantly reduce CV risk in people with and without T2D or MetS. However, the risk of major vascular events in those attaining the maximum levels of LDL-C-reduction is only reduced by around one-third, which leaves substantial residual risk. Recent studies suggest that low high-density lipoprotein-cholesterol (HDL-C) (<1 .0 mmol/l; 40 mg/dl) and high triglyceride levels (≥1.7 mmol/l; 150 mg/dl) are independent risk factors for CV disease and that the relationship between HDL-C and CV risk persists even when on-treatment LDL-C levels are low (<1.7 mmol/l; 70 mg/dl). European guidelines highlight the importance of reducing residual risk by targeting these risk factors in addition to LDL-C. This is particularly important in patients with T2D and MetS because obesity and high levels of glycated hemoglobin are directly related to low levels of HDL-C and high triglyceride. Although most statins have a similar low-density lipoprotein-lowering efficacy, differences in chemical structure and pharmacokinetic profile can lead to variations in pleiotropic effects (for example, high-density lipoprotein-elevating efficacy), adverse event profiles, and drug-drug interactions. The choice of statin should therefore depend on the needs of the individual patient. The following reviews will discuss the potential benefits of pitavastatin versus other statins in the treatment of patients with dyslipidemia and MetS or T2D, focusing on its effects on HDL-C quantity and quality, its potential impact on atherosclerosis and CV risk, and its metabolic characteristics that reduce the risk of drug interactions. Recent controversies surrounding the potentially diabetogenic effects of statins will also be discussed.     

Soil–vegetation relationships in cerrados under different fire frequencies

Fire is an important ecological factor that structures savannas, such as the cerrado, by selecting plant species and altering soil nutrient content. In Emas National Park, central Brazil, we compared soils under three different fire regimes and their relationship to the cerrado species they support. We collected 25 soil and vegetation samples at each site. We found differences in soil characteristics (p?<?0.05), with fertility and fire frequency positively related: in the annually burned site we found higher values of organic matter, nitrogen, and clay, whereas in the protected site we detected lower values of pH and higher values of aluminum. We also observed differences in plant community structure, with distinct floristic compositions in each site. Floristic composition was more related to sand proportion (intra-set correlation?=?0.834). Different fire frequencies increase environmental heterogeneity and beta diversity in the Brazilian cerrado.     

Coexistence in a guild of filter feeding caddis larvae: do different instars act as different species?

Summary Guild structure and coexistence of filter feeding caddis larvae was studied in three lake-outlet streams in northern Finland. Natural stones were used as sampling units, and for each stone measurements of six microhabitat variables were taken. Species and species instar relationships in the multivariate microhabitat space were analyzed by a method based on Principal Components Analysis. Seven species of filtering caddis larvae were found at the study sites, but detailed analysis was restricted to the four most abundant ones (Polycentropus flavomaculatus, Hydropsyche angustipennis, H. pellucidula, H. saxonica). P. flavomaculatus was the microhabitat generalist of the guild, whereas all the hydropsychids were narrowly specialized in at least one larval instar. In all species, different instars utilized the microhabitat somewhat differentially. Moss content and Froude number were significantly different between instar microhabitats in all comparisons. Ontogenetic niche changes not only separated species instars from each other, but also profoundly changed the biotic as well as abiotic environment of the species at different phases of larval development. This may have important effects on the dynamics of interacting species and, consequently, on the guild structure. While some of the more classical models of coexistence may also be relevant for understanding coexistence in this guild of sessile stream insects, ontogenetic niche changes clearly need to be taken into consideration in future studies of guild structure and species interactions of filter feeding caddisfly larvae.     

Independent duplications of α-amylase in different strains of Aspergillus oryzae

Aspergillus oryzae is a filamentous fungus that has arisen through the ancient domestication of Aspergillus flavus for making traditional oriental foods and beverages. In the many centuries A. oryzae has been used for fermenting the starch in rice to simple sugars, it has undergone selection for increased secretion of starch-degrading enzymes. In particular, all A. oryzae strains investigated thus far have two or more copies of a gene encoding α-amylase, whereas A. flavus has only one. Here we investigate the duplications leading to these copies in three A. oryzae strains. We find evidence of at least three separate duplications of α-amylase, an example of parallel evolution in a micro-organism under artificial selection. At least two of these duplications appear to be associated with activity of transposable elements of the Tc1/mariner class. Both involve a 9.1 kb element that terminates in inverted repeats, encodes a putative transposase and another putative protein of unknown function, and contains an unusual arrangement of four short internal imperfect repeats. Although "unusual Mariners" of this size have previously been identified in A. oryzae, Aspergillus fumigatus and Aspergillus nidulans, this is the first evidence we know of that at least some of them are active in modern times and that their activity can contribute to beneficial genetic changes.     

Genetic expression of β-mannosidase activity in different tissues of mice

Beta-Mannosidase activity of liver, kidney, and spleen of two inbred strains of mice and their crosses has been assayed with the synthetic aubstrate p-nitrophenyl-beta-d-mannoside. Activity is low in C57BL/Kl mice and high in DBA/2/Kl mice. Hybrid animals have intermediate levels of beta-mannosidase activity. Segregation of enzyme activities occurs in the F-2 and backcross generations, and there are good correlations between acitities in the three tissuses of F-2 and backcross animals. Some evidence points to a single gene difference in crosses between C57BL and DBA with respect to this mannosidase variation. Curves for enzyme activities at different substrate concentrations and pHs obtained with preparations from DBA and C57BL mice show some differences. These are interpreted as a possible strain variation in a structural gene for this enzyme.     

Rice caryopsis development Ⅰ: Dynamic changes in different cell layers

Rice caryopsis as one of the most important food sources for humans has a complex structure that is composed of maternal tissues including the pericarp and testa and filial tissues including the endosperm and embryo. Although rice caryopsis studies have been conducted previously, a systematic characterization throughout the entire developmental process is still lacking. In this study, detailed morphological examinations of caryopses were made during the entire 30-day developmental process. We observed some rapid changes in cell differentiation events and cataloged how cellular degeneration processes occurred in maternal tissues. The differentiations of tube cells and cross cells were achieved by 9 days after pollination(DAP). In the testa, the outer integument was degenerated by 3 DAP, while the outer layer of the inner integument degenerated by 7 DAP. In the nucellus, all tissues with the exception of the nucellar projection and the nucellar epidermis degenerated in the first 5 DAP. By 21 DAP, all maternal tissues, including vascular bundles, the nucellar projection and the nucellar epidermal cells were degenerated. In summary, this study provides a complete atlas of the dynamic changes in cell differentiation and degeneration for individual maternal cell layers of rice caryopsis.     

Plasma concentration of α-tocopherol in different free-ranging birds of prey

In this study, we investigated the α-tocopherol plasma concentrations in healthy free-ranging nestlings of the white-tailed sea eagle (Haliaeetus albicilla) (n = 32), osprey (Pandion haliaetus) (n = 39), northern goshawk (Accipiter gentilis) (n = 25), common buzzard (Buteo buteo) (n = 31), and honey buzzard (Pernis apivorus) (n = 18) as well as of free-ranging adults of the white-tailed sea eagle (n = 10), osprey (n = 31), and northern goshawk (n = 45). α-Tocopherol plasma concentrations were determined by reverse-phase high-performance liquid chromatography. α-Tocopherol plasma concentrations in nestlings of osprey, white-tailed sea eagle, and northern goshawk did not differ significantly amongst the species, but the common buzzard and honey buzzard nestlings had significantly lower α-tocopherol plasma concentrations than nestlings of the other species (both P < 0.001). Adult male ospreys and white-tailed sea eagles had significantly higher α-tocopherol concentrations compared to adult females (both P < 0.005). Adult ospreys and northern goshawks had significantly higher α-tocopherol plasma concentrations compared to their nestlings (both P < 0.001). In adult female northern goshawks, plasma concentrations of α-tocopherol increased significantly before egg laying (P < 0.001). These results demonstrate α-tocopherol plasma concentrations in birds of prey to be species specific and influenced by age and reproductive status.     

Epigenetics: imprinting in plants and mammals--the same but different?

Plants and animals both exhibit parental imprinting, but do they control it the same way? Recent studies show that in Arabidopsis, as in mammals, imprinted alleles are subject to DNA methylation--but, surprisingly, the default state is silence rather than activity.     

CMS sources in sunflower: different origin but same mechanism?

 The presence of orfH522, orfH708 and orfH873 in the mtDNA, as well as the expression of mitochondrially encoded proteins, were investigated for 28 sources of cytoplasmic male sterility (CMS) and HA89, a fertile line of Helianthus annuus. The whole 5-kb insertion, found in PET1, is also present in all PET1-like CMS sources. However, with regard to the 11-kb inversion ANO1 demonstrated a different organization at the cob locus from the other PET1-like CMS sources. Only orfH873 gave hybridization patterns in all investigated cytoplasms. For the fertile cytoplasm, as well as ANN4, ANN5, ANL1, ANL2, ARG2 and MAX1, hybridizations obtained with orfH708 were highly polymorphic. Hybridization signals with orfH522 were only detectable in the PET1-like CMS sources and MAX1. Comparing the mitochondrially encoded proteins of the CMS sources characteristic patterns could be detected for seven cytoplasms in addition to the PET1-like CMS sources expressing the 16-kDa protein. For ANN1 and ANN3 three CMS-associated proteins of 16.3 kDa, 16.9 kDa and 34.0 kDa could be identified among the in organello translation products. Also ANT1 expressed three additional proteins of 13.4 kDa, 17.8 kDa and 19.7 kDa, respectively. In ARG3 and RIG1 one protein of 17.5 kDa was missing and instead a new protein of 16.9 kDa appeared. In addition, in GIG1 and PET2 a unique protein of 12.4 kDa could be identified. These results indicate that certain types of cytoplasmic male sterility are preferentially present in sunflower. Received: 15 June 1998 / Accepted: 13 July 1998     

Ghrelin and obestatin: different role in fetal lung development?

Ghrelin and obestatin are two proteins that originate from post-translational processing of the preproghrelin peptide. Various authors claim an opposed role of ghrelin and obestatin in several systems. Preproghrelin mRNA is significantly expressed in airway epithelium throughout lung development, predominantly during the earliest stages. The aim of this study was to evaluate the role of ghrelin and obestatin in fetal lung development in vitro. Immunohistochemistry studies were performed at different gestational ages in order to clarify the expression pattern of ghrelin, GHS-R1a, obestatin and GPR39 during fetal lung development. Fetal rat lung explants were harvested at 13.5 days post-conception (dpc) and cultured during 4 days with increasing doses of total ghrelin, acylated ghrelin, desacyl-ghrelin, ghrelin antagonist (D-Lys(3)-GHRP-6) or obestatin. Immunohistochemistry studies demonstrated that ghrelin, GHS-R1a, obestatin and GPR39 proteins were expressed in primitive rat lung epithelium throughout all studied gestational ages. Total and acylated ghrelin supplementation significantly increased the total number of peripheral airway buds, whereas desacyl-ghrelin induced no effect. Moreover, GHS-R1a antagonist significantly decreased lung branching. Finally, obestatin supplementation induced no significant effect in the measured parameters. The present study showed that ghrelin has a positive effect in fetal lung development through its GHS-R1a receptor, whereas obestatin has no effect on lung branching.