Facultative and obligate diapause phenotypes in populations of the European spruce bark beetle Ips typographus

The bark beetle Ips typographus is the most destructive insect pest in Norway spruce-dominated forests. Its potential to establish multiple generations per year (multivoltinism) is one major trait that makes this beetle a severe pest. Ips typographus enters diapause to adjust its life cycle to seasonally changing environments. Diapause is characterized by developmental and reproductive arrest; it prolongs generation time and thus affects voltinism. In I. typographus a facultative, photoperiod-regulated diapause in the adult stage has been described. In addition, the presence of an obligate, photoperiod-independent, diapause has been hypothesized. The diapause phenotype has important implications for I. typographus voltinism, as populations with obligate diapausing individuals would be univoltine. To test for the presence of different I. typographus diapause phenotypes, we exposed Central and Northern European individuals to a set of photoperiodic treatments. We used two ovarian traits (egg number and vitellarium size) that are associated with gonad development, to infer reproductive arrest and thus diapause. We found a distinct effect of photoperiod on ovarian development, with variable responses in Central and Northern European beetles. We observed obligate diapausing (independent of photoperiod) individuals in Northern Europe, and both facultative (photoperiod-regulated) as well as obligate diapausing individuals in Central Europe. Our results show within-species variation for diapause induction, an adaptation to match life cycles with seasonally fluctuating environmental conditions. As the diapause phenotype affects the potential number of generations per season, our data are the basis for assessing the risk of outbreaks of this destructive bark beetle.

     

Social-ethical issues concerning the control strategy of animal diseases in the European Union: A survey

In 2004 a survey was conducted in the member states of the European Union designed to gain greater insight into the views on control strategies for foot and mouth disease, classical swine fever, and avian influenza with respect to the epidemiological, economic and social-ethical consequences of each of these animal diseases. This article presents the results of the social-ethical survey. A selection of stakeholders from each member state was asked to prioritize issues for the prevention and control of these diseases. A majority of stakeholders chose preventive measures as the preferred issue. An analysis was done to determine whether there were differences in views expressed by stakeholders from member states with a history of recent epidemics and ones without such a history, and whether there were regional differences. There were no differences between member states with or without a history of recent epidemics. There were indeed regional differences between the priority orders from Northern and Southern Europe on the one hand, and from Eastern Europe on the other. Nina E. Cohen is a biologist and is a researcher at the Wageningen University. She is specialized in societal and ethical issues in human–animal relationships. Her current research is focused on the social-ethical issues concerning the prevention and control of foot and mouth disease, classical swine fever and avian influenza. Marcel A.P.M. van Asseldonk has studied animal science. Currently he works at the Institute for Risk Management in Agriculture (IRMA) of the Wageningen University. He is specialized in the design and pricing of insurance policies and animal health funds for the main livestock epidemics. Elsbeth N. Stassen is a veterinarian and professor of Animals and Society at the Wageningen University. Elsbeth Stassen is specialized in animal health, animal welfare and human–animal relationships. She was a member of a governmental welfare committee during the avian influenza epidemic in the Netherlands in 2003.     

Reversible changes in cell morphology due to cytoskeletal rearrangements measured in real-time by QCM-D

The mechanical properties and responses of cells to external stimuli (including drugs) are closely connected to important phenomena such as cell spreading, motility, activity, and potentially even differentiation. Here, reversible changes in the viscoelastic properties of surface-attached fibroblasts were induced by the cytoskeleton-perturbing agent cytochalasin D, and studied in real-time by the quartz crystal microbalance with dissipation (QCM-D) technique. QCM-D is a surface sensitive technique that measures changes in (dynamically coupled) mass and viscoelastic properties close to the sensor surface, within a distance into the cell that is usually only a fraction of its size. In this work, QCM-D was combined with light microscopy to study in situ cell attachment and spreading. Overtone-dependent changes of the QCM-D responses (frequency and dissipation shifts) were first recorded, as fibroblast cells attached to protein-coated sensors in a window equipped flow module. Then, as the cell layer had stabilised, morphological changes were induced in the cells by injecting cytochalasin D. This caused changes in the QCM-D signals that were reversible in the sense that they disappeared upon removal of cytochalasin D. These results are compared to other cell QCM-D studies. Our results stress the combination of QCM-D and light microscopy to help interpret QCM-D results obtained in cell assays and thus suggests a direction to develop the QCM-D technique as an even more useful tool for real-time cell studies.     

Low water activity induces the production of bioactive metabolites in halophilic and halotolerant fungi

The aim of the present study was to investigate indigenous fungal communities isolated from extreme environments (hypersaline waters of solar salterns and subglacial ice), for the production of metabolic compounds with selected biological activities: hemolysis, antibacterial, and acetylcholinesterase inhibition. In their natural habitats, the selected fungi are exposed to environmental extremes, and therefore the production of bioactive metabolites was tested under both standard growth conditions for mesophilic microorganisms, and at high NaCl and sugar concentrations and low growth temperatures. The results indicate that selected halotolerant and halophilic species synthesize specific bioactive metabolites under conditions that represent stress for non-adapted species. Furthermore, adaptation at the level of the chemical nature of the solute lowering the water activity of the medium was observed. Increased salt concentrations resulted in higher hemolytic activity, particularly within species dominating the salterns. The appearance of antibacterial potential under stress conditions was seen in the similar pattern of fungal species as for hemolysis. The active extracts exclusively affected the growth of the Gram-positive bacterium tested, Bacillus subtilis. None of the extracts tested showed inhibition of acetylcholinesterase activity.     

Toll-like receptor-mediated anti-inflammatory action of glaucine and oxoglaucine

Two isochinoline alkaloids, glaucine and oxoglaucine were investigated for their suggested anti-inflammatory influence concerning nitric oxide and cytokine production. Mouse peritoneal macrophages were stimulated with different Toll-like receptor (TLR) ligands such as LPS for TLR4, zymosan for TLR2 and CpG for TLR9. The alkaloids inhibited TNF-α and IL-6 production induced by these ligands. In regard to IL-12 suppressive effect was registered in the case of CpG stimulation. Glaucine succeeded to enhance LPS and zymosan-induced IL-10 production. The reduction of pro-inflammatory cytokines and increase of anti-inflammatory IL-10 are indicative for their use in different acute and chronic inflammatory diseases.     

Dentate gyrus NMDA receptors mediate rapid pattern separation in the hippocampal network

Forming distinct representations of multiple contexts, places, and episodes is a crucial function of the hippocampus. The dentate gyrus subregion has been suggested to fulfill this role. We have tested this hypothesis by generating and analyzing a mouse strain that lacks the gene encoding the essential subunit of the N-methyl-d-aspartate (NMDA) receptor NR1, specifically in dentate gyrus granule cells. The mutant mice performed normally in contextual fear conditioning, but were impaired in the ability to distinguish two similar contexts. A significant reduction in the context-specific modulation of firing rate was observed in the CA3 pyramidal cells when the mutant mice were transferred from one context to another. These results provide evidence that NMDA receptors in the granule cells of the dentate gyrus play a crucial role in the process of pattern separation.     

Mass spectrometry of intact V-type ATPases reveals bound lipids and the effects of nucleotide binding

The ability of electrospray to propel large viruses into a mass spectrometer is established and is rationalized by analogy to the atmospheric transmission of the common cold. Much less clear is the fate of membrane-embedded molecular machines in the gas phase. Here we show that rotary adenosine triphosphatases (ATPases)/synthases from Thermus thermophilus and Enterococcus hirae can be maintained intact with membrane and soluble subunit interactions preserved in vacuum. Mass spectra reveal subunit stoichiometries and the identity of tightly bound lipids within the membrane rotors. Moreover, subcomplexes formed in solution and gas phases reveal the regulatory effects of nucleotide binding on both ATP hydrolysis and proton translocation. Consequently, we can link specific lipid and nucleotide binding with distinct regulatory roles.     

Atmospheric carbon injection linked to end-Triassic mass extinction

The end-Triassic mass extinction (~201.4 million years ago), marked by terrestrial ecosystem turnover and up to ~50% loss in marine biodiversity, has been attributed to intensified volcanic activity during the break-up of Pangaea. Here, we present compound-specific carbon-isotope data of long-chain n-alkanes derived from waxes of land plants, showing a ~8.5 per mil negative excursion, coincident with the extinction interval. These data indicate strong carbon-13 depletion of the end-Triassic atmosphere, within only 10,000 to 20,000 years. The magnitude and rate of this carbon-cycle disruption can be explained by the injection of at least ~12 × 10(3) gigatons of isotopically depleted carbon as methane into the atmosphere. Concurrent vegetation changes reflect strong warming and an enhanced hydrological cycle. Hence, end-Triassic events are robustly linked to methane-derived massive carbon release and associated climate change.     

Regulation of Innate Immune Function in Bovine Oviduct Epithelial Cells in Culture: The Homeostatic Role of Epithelial Cells in Balancing Th1/Th2 Response

This study aimed to investigate the role of epithelial cells in regulating innate immunity in bovine oviduct epithelial cell (BOEC) culture. We studied the effect of Escherichia coli lipopolysaccharide (LPS) and its interaction with ovarian steroids, estradiol (E2) and progesterone (P4), and luteinizing hormone (LH) at concentrations observed during the preovulatory period on immune responses in BOEC culture. Immunohistochemistry of oviduct tissue showed intensive expression of Toll-like receptor-4 (TLR-4) and TLR-2 in epithelial cells. A dose of 10 ng/ml LPS stimulated TLR-4, cyclooxygenase-2 (COX-2), nuclear factor kappa B inhibitor A (NFKBIA), interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) expression, indicating an early pro-inflammatory response. A dose of 100 ng/ml LPS did not induce expression of these genes but stimulated TLR-2, IL-10,IL-4 and microsomal prostaglandin E synthase-1 (mPGES-1) expression and PGE2 secretion, indicating an anti-inflammatory response. Ovarian steroids and LH completely block LPS (10 ng/ml)-induced TLR-4, IL-1β and TNF-α expression as well as LPS (100 ng/ml)-induced TLR-2 expression. Taken together, this study suggests the existence of an early signaling system to respond to infection in the BOEC. In addition, ovarian steroids and LH may play a critical role in inducing homeostasis and in controlling hyperactive pro-inflammatory responses detrimental to epithelial cells, sperm and the embryo.