Physics, Theoretical Knowledge and Weinberg's Grand Reductionism

The two main points of this contribution are the following: (1) Applied mathematical theories might complement physical theories in an essential way; some applied mathematical theories allow us to understand phenomena we are unable to explain by resorting to physical theories alone, (2) In the case of social sciences it might be necessary to account for examined phenomena by resorting to the idea of goal-oriented activity (the causal approach typical for natural science might be unsatisfactory). Weinberg's idea of grand reductionism ignores the two above mentioned facts and hence overestimates the foundational role of physics and its methodology.     

Annotated checklist and distribution of Culicoides biting midges of Ukraine (Diptera: Ceratopogonidae)

Despite the great socio-economic impact of Culicoides-borne diseases, there is little work on the reassessment of the faunistic and distributional data on this important group of vectors in the territory of Ukraine. Along with the literature review, materials were collected and slide-mounted using the conventional techniques for this study. The revised and commented list of 55 valid species names of the genus Culicoides recorded from Ukraine and their distribution is presented. New collection localities are given for Culicoides griseidorsum Kieffer, Culicoides atripennis Shevchenko and Culicoides newsteadi s.l. Culicoides triangulatus Shevchenko and Culicoides ukrainensis Shevchenko described from Ukraine are recognized as nomina dubia, whereas Culicoides tentorius Austen and Culicoides furcillatus Callot, Kremer and Paradis were excluded from the list. The current state of knowledge on Ukrainian Culicoides fauna should be characterized as rather understudied. Collectively, this suggests that further research efforts are needed, especially in view of the fact that the species recognized as vectors of the economically important diseases of animals are among the most abundant representatives of the genus. Moreover, the article highlights taxonomic problems within certain taxa and provides an outline of its further research perspectives.     

Bacteriophages targeting intestinal epithelial cells: a potential novel form of immunotherapy

In addition to their established role as a physical barrier to invading pathogens and other harmful agents, intestinal epithelial cells (IEC) are actively involved in local immune reactions. In the past years, evidence has accumulated suggesting the role of IEC in the immunopathology of intestinal inflammatory disorders (IBD). Recent advances in research on bacteriophages strongly suggest that—in addition to their established antibacterial activity—they have immunomodulating properties that are potentially useful in the clinic. We suggest that these immunomodulating phage activities targeting IEC may open novel treatment perspectives in disorders of the alimentary tract, particularly IBD.     

"Białkowski Panel" - Introduction and Acknowledgements

The two main points of this contribution are the following: (1) Applied mathematical theories might complement physical theories in an essential way; some applied mathematical theories allow us to understand phenomena we are unable to explain by resorting to physical theories alone, (2) In the case of social sciences it might be necessary to account for examined phenomena by resorting to the idea of goal-oriented activity (the causal approach typical for natural science might be unsatisfactory). Weinberg's idea of grand reductionism ignores the two above mentioned facts and hence overestimates the foundational role of physics and its methodology. This revised version was published online in July 2006 with corrections to the Cover Date.     

Epistatic buffering of fitness loss in yeast double deletion strains

Interactions between deleterious mutations have been insufficiently studied, despite the fact that their strength and direction are critical for understanding the evolution of genetic recombination and the buildup of mutational load in populations. We compiled a list of 758 yeast gene deletions causing growth defects (from the Munich Information Center for Protein Sequences database and ref. 7). Using BY4741 and BY4742 single-deletion strains, we carried out 639 random crosses and assayed growth curves of the resulting progeny. We show that the maximum growth rate averaged over strains lacking deletions and those with double deletions is higher than that of strains with single deletions, indicating a positive epistatic effect. This tendency is shared by genes belonging to a variety of functional classes. Based on our data and former theoretical work, we suggest that epistasis is likely to diminish the negative effects of mutations when the ability to produce biomass at high rates contributes significantly to fitness.     

Neuropsin cleaves EphB2 in the amygdala to control anxiety

A minority of individuals experiencing traumatic events develop anxiety disorders. The reason for the lack of correspondence between the prevalence of exposure to psychological trauma and the development of anxiety is unknown. Extracellular proteolysis contributes to fear-associated responses by facilitating neuronal plasticity at the neuron-matrix interface. Here we show in mice that the serine protease neuropsin is critical for stress-related plasticity in the amygdala by regulating the dynamics of the EphB2-NMDA-receptor interaction, the expression of Fkbp5 and anxiety-like behaviour. Stress results in neuropsin-dependent cleavage of EphB2 in the amygdala causing dissociation of EphB2 from the NR1 subunit of the NMDA receptor and promoting membrane turnover of EphB2 receptors. Dynamic EphB2-NR1 interaction enhances NMDA receptor current, induces Fkbp5 gene expression and enhances behavioural signatures of anxiety. On stress, neuropsin-deficient mice do not show EphB2 cleavage and its dissociation from NR1 resulting in a static EphB2-NR1 interaction, attenuated induction of the Fkbp5 gene and low anxiety. The behavioural response to stress can be restored by intra-amygdala injection of neuropsin into neuropsin-deficient mice and disrupted by the injection of either anti-EphB2 antibodies or silencing the Fkbp5 gene in the amygdala of wild-type mice. Our findings establish a novel neuronal pathway linking stress-induced proteolysis of EphB2 in the amygdala to anxiety.