Some aspects of spiralian development

Nielsen, C. 2010. Some aspects of spiralian development. —Acta Zoologica (Stockholm) 91 : 20–28 Spiralian development is not only a characteristic early cleavage pattern, with shifting orientations of the cleavage planes, but also highly conserved cell lineages, where the origin of several organs can be traced back to identifiable cells in the lineage. These patterns are well documented in annelids, molluscs, nemertines, and platyhelminths and are considered ancestral of a bilaterian clade including these phyla. Spiral cleavage has not been documented in ecdysozoans, and no trace of the spiral development pattern is seen in phoronids and brachiopods. Origin of the spatial organization in spiralian embryos is puzzling, but much of the information appears to be encoded in the developing oocyte. Fertilization and “pseudofertilization” apparently provides the information defining the secondary, anterior‐posterior body axis in many species. The central nervous system consists of three components: an apical organ, derived from the apical blastomeres 1a¹¹¹‐1d¹¹¹, which degenerates before or at metamorphosis; the cerebral ganglia derived from other blastomeres of the first micromere quartet and retained in the adult as a preoral part of the brain; and the originally circumblastoporal nerve cord, which has become differentiated into a perioral part of the brain, the paired or secondarily fused ventral nerve cords, and a small perianal nerve ring.     

Effects of alternative styles of risk information on EMF risk perception

Risk scenarios characterized by exposures to new technologies with unknown health effects, together with limited appreciation of benefits pose a challenge to risk communication. The present report illustrates this situation through a study of the perceived risk from mobile phones and mobile masts in residential areas. Good information should objectively convey the current state of knowledge. The research question is then how to inform lay people so that they trust and understand the information. We used an Internet‐based survey with 1687 Danish participants randomized to three types of information about radiation from mobile phones and masts. The objective was to study whether different types of information were rated as equally useful, informative, comprehensible, and trustworthy. Moreover, an important issue was whether information would influence risk perception and intended behavior. The conclusion is that lay people rate information about risks associated with a new and largely unknown technology more useful and trustworthy when provided with brief statements about how to handle the risk, rather than more lengthy technical information about why the technology may or may not entail health hazards. Further, the results demonstrate that information may increase concern among a large proportion of the population, and that discrepancies exist between expressed concern and intended behavior. Bioelectromagnetics 31:504–512, 2010. © 2010 Wiley‐Liss, Inc.     

Endocytosis of apolipoprotein A-V by members of the low density lipoprotein receptor and the VPS10p domain receptor families

Apolipoprotein A-V (apoA-V) is present in low amounts in plasma and has been found to modulate triacylglycerol levels in humans and in animal models. ApoA-V displays affinity for members of the low density lipoprotein receptor (LDL-R) gene family, known as the classical lipoprotein receptors, including LRP1 and SorLA/LR11. In addition to LDL-A binding repeats, the mosaic receptor SorLA/LR11 also possesses a Vps10p domain. Here we show that apoA-V also binds to sortilin, a receptor from the Vsp10p domain gene family that lacks LDL-A repeats. Binding of apoA-V to sortilin was competed by neurotensin, a ligand that binds specifically to the Vps10p domain. To investigate the biological fate of receptor-bound apoA-V, binding experiments were conducted with cultured human embryonic kidney cells transfected with either SorLA/LR11 or sortilin. Compared with nontransfected cells, apoA-V binding to SorLA/LR11- and sortilin-expressing cells was markedly enhanced. Internalization experiments, live imaging studies, and fluorescence resonance energy transfer analyses demonstrated that labeled apoA-V was rapidly internalized, co-localized with receptors in early endosomes, and followed the receptors through endosomes to the trans-Golgi network. The observed decrease of fluorescence signal intensity as a function of time during live imaging experiments suggested ligand uncoupling in endosomes with subsequent delivery to lysosomes for degradation. This interpretation was supported by experiments with (125)I-labeled apoA-V, demonstrating clear differences in degradation between transfected and nontransfected cells. We conclude that apoA-V binds to receptors possessing LDL-A repeats and Vsp10p domains and that apoA-V is internalized into cells via these receptors. This could be a mechanism by which apoA-V modulates lipoprotein metabolism in vivo.     

Freeze-preservation of rice cells: A physiological study of freeze-thawed cells

Rice ( Oryza sativa L.) cells returning to in vitro culture after preservation at superlow temperature in liquid nitrogen are characterized by a number of physiological alterations. These include: reduction in respiration and glucose uptake, loss of intracellular potassium, decrease in the cellular level of key metabolites (ATP, glucose-6-phosphate and pyruvate) and fragility of protoplasts following the action of cell wall-degrading enzymes.
Nevertheless, cell growth resumes after a short lag phase (2–4 days) with an actual 70–100% cell survival, thus indicating that the observed damage is not lethal and can be repaired in a short time.     

Association studies under general disease models

There is great expectation that the levels of association found between genetic markers and disease status will play a role in the location of disease genes. This expectation follows from regarding association as being proportional to linkage disequilibrium and therefore inversely related to recombination value. For disease genes with more than two alleles, the association measure is instead a weighted average of linkage disequilibria, with the weights depending on allele frequencies and genotype susceptibilities at the disease loci. There is no longer a simple relationship, even in expectation, with recombination. We adopt a general framework to examine association mapping methods which helps to clarify the nature of case-control and transmission/disequilibrium-type tests and reveals the relationship between measures of association and coefficients of linkage disequilibrium. In particular, we can show the consequences of additive and nonadditive effects at the trait locus on the behavior of these tests. These concepts have a natural extension to marker haplotypes. The association of two-locus marker haplotypes with disease phenotype depends on a weighted average of three-locus disequilibria (two markers with each disease locus). It is likely that these two-marker analyses will provide additional information in association mapping studies.     

Altered activation state of circulating neutrophils in patients with neovascular age-related macular degeneration

Background

Neutrophil dysfunction plays a key role in the development of diseases characterized by inflammation and angiogenesis. Here, we studied the systemic expression of neutrophil markers reflecting activation, adhesion, and resolution of inflammation in patients with neovascular age-related macular degeneration (AMD).

Results

This was a prospective case-control study of patients with neovascular AMD and age-matched healthy control individuals. Patients were recruited from an outpatient program, and control individuals were recruited amongst patients’ relatives. Current smokers and individuals with either active immune-disease or ongoing cancer were not included, as these factors are known to affect neutrophil function. Fresh-drawn venous blood was processed for flow cytometric analysis of neutrophil markers. We determined percentages of positive cells and compared expression levels using fluorescence intensity measures. We found conditional differences on marker expression between patients with neovascular AMD (n = 29) and controls (n = 28): no differences were found when looking broadly, but several differences emerged when focusing on non-smokers. Here, patients with neovascular AMD had increased expression of the activity marker cluster of differentiation (CD) 66b (P = 0.003; Mann-Whitney U test), decreased expression of adhesion marker CD162 (P = 0.044; Mann-Whitney U test), and lower expression of the resolution of inflammation marker C-X-C chemokine receptor 2 (P = 0.044; Mann-Whitney U test).

Conclusions

We present novel evidence suggesting that the activity of circulating neutrophils, sensitive to smoking, may differ in patients with neovascular AMD.

     

Association of the M blood group system with bovine mastitis

Associations of the 11 bovine blood group systems with mastitis were examined in Red Danish dairy cattle. The mastitis status was followed during three lactational periods. A significant effect of the M blood group system on mastitis incidence was observed in the first and second lactation periods and a lower frequency of mastitis is found among animals lacking the M' factor as compared to those having the M' blood group factor. The significance of these results are discussed in view of the close relation between the M blood group system and the bovine lymphocyte antigens (BoLA), and the expected effect of eliminating the M' gene from the breed is estimated. Among the remaining 10 blood group systems, the T' system was the only system showing an overall effect on mastitis, and only in first and third lactation. However, the T' system was inconsistent with regard to the effect of the T' gene on the various mastitis diagnoses.