Evaluation of sexual dimorphism of histochemical activity of phosphatases of the plantar glands of Norway rats (Rattus norvegicus)

The activity of acid phosphatase, alkaline phosphatase and adenosine triphosphatase in the eccrine and sebaceous glands of the skin of the soles of the paws of male and female Norway rats was studied by histochemiсal methods. Using the methods of qualimetric analysis, we presented a digitalized form of the enzyme activity, which made it possible to calculate sexual dimorphism indices, reflecting quantitative differences in the enzymatic activity of the skin glands in males and females of Norway rats. For acid phosphatase activity, the sexual dimorphism index was equal to 0.50 in the eccrine glands and equal to 0.33 in the sebaceous glands. For alkaline phosphatase activity, values of sexual dimorphism indices were equal to –0.25 and 0.33 correspondingly, and for adenosine triphosphatase values of sexual dimorphism indices were equal to –0.33 and 0.50. Digital analogues of the histoenzymatic activity of the skin glands were presented as coordinates in three-dimensional space. Using the methods of analytical geometry, we calculated the values of intersexual distances (1.73 for eccrine glands and 1.73 for sebaceous glands), reflecting the cumulative differences in the activity of three types of phosphatases, which can be considered as an integral indicator of sexual dimorphism. Histochemical activity entropy is significant in the eccrine glands. Male entropy value (0.842 bit) was less than female entropy value (0.915 bit), because total actual activity of the males’ phosphatases was greater (220% of 300%) than total actual activity of the females’ phosphatases (200% of 300%). High entropy level of phosphatase activity was typical for male sebaceous glands (0.998 bit), where the general level of enzymatic activity was significantly reduced (160% of 300%). Because of the highest total actual phosphatase activity of female sebaceous glands (220% of 300%), entropy value was the lowest (0.842 bit). The obtained results show not only sexual dimorphism by histochemical parameters but show different communicational levels of male and female Norway rats, taking into account the important role of the plantar glands as sources of chemical signals determining the character of marking behaviour

Early Pleistocene enamel proteome from Dmanisi resolves Stephanorhinus phylogeny

The sequencing of ancient DNA has enabled the reconstruction of speciation, migration and admixture events for extinct taxa. However, the irreversible post-mortem degradation2 of ancient DNA has so far limited its recovery—outside permafrost areas—to specimens that are not older than approximately 0.5 million years (Myr). By contrast, tandem mass spectrometry has enabled the sequencing of approximately 1.5-Myr-old collagen type I, and suggested the presence of protein residues in fossils of the Cretaceous period—although with limited phylogenetic use. In the absence of molecular evidence, the speciation of several extinct species of the Early and Middle Pleistocene epoch remains contentious. Here we address the phylogenetic relationships of the Eurasian Rhinocerotidae of the Pleistocene epoch, using the proteome of dental enamel from a Stephanorhinus tooth that is approximately 1.77-Myr old, recovered from the archaeological site of Dmanisi (South Caucasus, Georgia). Molecular phylogenetic analyses place this Stephanorhinus as a sister group to the clade formed by the woolly rhinoceros (Coelodonta antiquitatis) and Merck’s rhinoceros (Stephanorhinus kirchbergensis). We show that Coelodonta evolved from an early Stephanorhinus lineage, and that this latter genus includes at least two distinct evolutionary lines. The genus Stephanorhinus is therefore currently paraphyletic, and its systematic revision is needed. We demonstrate that sequencing the proteome of Early Pleistocene dental enamel overcomes the limitations of phylogenetic inference based on ancient collagen or DNA. Our approach also provides additional information about the sex and taxonomic assignment of other specimens from Dmanisi. Our findings reveal that proteomic investigation of ancient dental enamel—which is the hardest tissue in vertebrates, and is highly abundant in the fossil record—can push the reconstruction of molecular evolution further back into the Early Pleistocene epoch, beyond the currently known limits of ancient DNA preservation

Can environment or allergy explain international variation in prevalence of wheeze in childhood?

Asthma prevalence in children varies substantially around the world, but the contribution of known risk factors to this international variation is uncertain. The International Study of Asthma and Allergies in Childhood (ISAAC) Phase Two studied 8–12 year old children in 30 centres worldwide with parent-completed symptom and risk factor questionnaires and aeroallergen skin prick testing. We used multilevel logistic regression modelling to investigate the effect of adjustment for individual and ecological risk factors on the between-centre variation in prevalence of recent wheeze. Adjustment for single individual-level risk factors changed the centre-level variation from a reduction of up to 8.4% (and 8.5% for atopy) to an increase of up to 6.8%. Modelling the 11 most influential environmental factors among all children simultaneously, the centre-level variation changed little overall (2.4% increase). Modelling only factors that decreased the variance, the 6 most influential factors (synthetic and feather quilt, mother’s smoking, heating stoves, dampness and foam pillows) in combination resulted in a 21% reduction in variance. Ecological (centre-level) risk factors generally explained higher proportions of the variation than did individual risk factors. Single environmental factors and aeroallergen sensitisation measured at the individual (child) level did not explain much of the between-centre variation in wheeze prevalence