Marta Walczak

Canine Olfactory Receptor Gene Polymorphism and Its Relation to Odor Detection Performance by Sniffer Dogs

The outstanding sensitivity of the canine olfactory system has been acknowledged by using sniffer dogs in military and civilian service for detection of a variety of odors. It is hypothesized that the canine olfactory ability is determined by polymorphisms in olfactory receptor (OR) genes. We investigated 5 OR genes for polymorphic sites which might affect the olfactory ability of service dogs in different fields of specific substance detection. All investigated OR DNA sequences proved to have allelic variants, the majority of which lead to protein sequence alteration. Homozygous individuals at 2 gene loci significantly differed in their detection skills from other genotypes. This suggests a role of specific alleles in odor detection and a linkage between single-nucleotide polymorphism and odor recognition efficiency.

Epigenetics of cell fate reprogramming and its implications for neurological disorders modelling

The reprogramming of human induced pluripotent stem cells (hiPSCs) proceeds in a stepwise manner with reprogramming factors binding and epigenetic composition changes during transition to maintain the epigenetic landscape, important for pluripotency. There arises a question as to whether the aberrant epigenetic state after reprogramming leads to epigenetic defects in induced stem cells causing unpredictable long term effects in differentiated cells. In this review, we present a comprehensive view of epigenetic alterations accompanying reprogramming, cell maintenance and differentiation as factors that influence applications of hiPSCs in stem cell based technologies. We conclude that sample heterogeneity masks DNA methylation signatures in subpopulations of cells and thus believe that beside a genetic evaluation, extensive epigenomic screening should become a standard procedure to ensure hiPSCs state before they are used for genome editing and differentiation into neurons of interest. In particular, we suggest that exploitation of the single-cell composition of the epigenome will provide important insights into heterogeneity within hiPSCs subpopulations to fast forward development of reliable hiPSC-based analytical platforms in neurological disorders modelling and before completed hiPSC technology will be implemented in clinical approaches.

Do Trained Dogs Discriminate Individual Body Odors of Women Better than Those of Men

Abstract:  Scent identification lineups using dogs are a potentially valuable forensic tool, but have been dismissed by some critics because of cases where a false identification was shown to have occurred. It is not known, however, why dogs appear to make more false indications to the odors of some persons than of others. In this study, human genders were compared as to the degree their individual odors are distinguishable or “attractive” to dogs. Six dogs were trained to smell an individual’s hand odor sample and then find the matching hand odor sample in a lineup of five odors. Using one‐gender lineups and two‐gender lineups with different gender ratios, it was found that dogs trained for the study identified individual women’s hand odors more accurately than those of men. It is hypothesized that this is either because of differences in chemical compounds making discrimination of women’s odors easier, or because of greater “odor attractiveness” of women’s scents to dogs.

A New Approach to Identification of Biomarkers for Early Cancer Stage Detection

Abstract Gas chromatography and mass spectrometry (GC/MS) was applied for determination of concentrations volatile organic compounds present in human breath samples. The technique allows to rapid determination compounds in human air, at the level of parts per billion. It showed linear correlations ranging from 0.83-234.05 ppb, limit detection in the range of 0.31-0.75 ppb and precision, expressed as RSD, was less then 10.00%. Moreover, trained dogs are able to discriminate breath samples of patients with diagnosed cancer disease. We found positive correlation between dog indications and content of ethyl acetate and 2- pentanone in breath (r=0.85 and r=0.97, respectively)

Differences between an “ideal” detection dog and dogs used by the police

Prompted by these studies and by recent evidence showing that the domestic dog (Canis familiaris) has complex cognitive skills in interacting with humans, we: i) discuss the possibility that this species may have developed the capacity to empathize with humans at a level beyond emotional contagion; ii) briefly refer to the available evidence supporting this hypothesis; and iii) outline some routes for further studies to address, in detail, the exact level of emotional and cognitive processing in dogs’ empathy toward humans. Also we call for attentions on dog-assisted interventions as a particularly promising scenario to conduct experimental studies on this topic. As a collection of functional behavioral convergences with humans, the study of dog social cognition may bring important insights to the current understanding of the emergence of complex human social skills. More specifically, the exploration of dogs’ possible empathic tendencies towards humans may turn out to be very useful for increasing knowledge about the development and maintenance of affective bonds and emotional communication between individuals and social groups.