Modulation of the tissue composition of regenerative neuroma by dexamethasone and granulocyte colony-stimulating factor

Aim. To evaluate the change of the content of mesenchymal (vimentin-positive) and reparative Schwann (GFAP-positive) cells in the regenerative neuroma of the rat sciatic nerve, taking into account the activity of local homeostasis regulation (CD73 expression) under the influence of dexamethasone (Dex) and granulocyte colony-stimulating factor (GCSF). Materials and methods. Vimentin-, GFAP-, and CD73-positive cells were detected immunohistochemically in the regenerative neuroma of 168 male Wistar rats, and their presence was quantified using statistical methods. Results. The regenerative neuroma of the sciatic nerve is characterized by a stereotypical cellular composition kinetics. Dexamethasone, during the initial stage of neuroma formation (1–7 days), led to a reduction in inflammatory infiltration and accumulation of vimentin+ mesenchymal cells. It significantly accelerated the accumulation of neural GFAP+ reparative Schwann cells and suppressed the expression of CD73. The granulocyte colony-stimulating factor (1–3 days) in the regenerative neuroma resulted in a slight reduction in inflammatory infiltration and an increase in the number of blood vessels penetrating into it. Under these conditions, the speed and quantity of vimentin+ cell accumulation and CD73 expression noticeably increased, as well as the speed of GFAP+ cell accumulation. The deviations in the expression of vimentin, GFAP, and CD73 in the neuroma under the administration of the mentioned substances gradually decreased and, after 8 weeks of the experiment, did not differ significantly from the control. When combined, dexamethasone and granulocyte colony-stimulating factor potentiated each other’s effects and, in addition, led to long-term maintenance of high CD73 expression. At the same time, the most pronounced approximation of the structure of the newly formed part of the nerve to the structure of the intact nerve trunk was observed. Conclusions. The simultaneous action of Dex and GCSF during the initial stages of regenerative neuroma formation, in contrast to their individual actions, not only alters the dynamics of mesenchymal and neural cell accumulation but also modifies the newly formed part of the nerve, bringing its structure closer to the intact state. This phenomenon is accompanied by increased reactivity of neurolemocytes during the axial cylinder germination stage of neuroma regeneration

Prior Mating Experience Modulates the Dispersal of Drosophila in Males More Than in Females

Cues from both an animal’s internal physiological state and its local environment may influence its decision to disperse. However, identifying and quantifying the causative factors underlying the initiation of dispersal is difficult in uncontrolled natural settings. In this study, we automatically monitored the movement of fruit flies and examined the influence of food availability, sex, and reproductive status on their dispersal between laboratory environments. In general, flies with mating experience behave as if they are hungrier than virgin flies, leaving at a greater rate when food is unavailable and staying longer when it is available. Males dispersed at a higher rate and were more active than females when food was unavailable, but tended to stay longer in environments containing food than did females. We found no significant relationship between weight and activity, suggesting the behavioral differences between males and females are caused by an intrinsic factor relating to the sex of a fly and not simply its body size. Finally, we observed a significant difference between the dispersal of the natural isolate used throughout this study and the widely-used laboratory strain, Canton-S, and show that the difference cannot be explained by allelic differences in the foraging gene

A model species for agricultural pest genomics: the genome of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

The Colorado potato beetle is one of the most challenging agricultural pests to manage. It has shown a spectacular ability to adapt to a variety of solanaceaeous plants and variable climates during its global invasion, and, notably, to rapidly evolve insecticide resistance. To examine evidence of rapid evolutionary change, and to understand the genetic basis of herbivory and insecticide resistance, we tested for structural and functional genomic changes relative to other arthropod species using genome sequencing, transcriptomics, and community annotation. Two factors that might facilitate rapid evolutionary change include transposable elements, which comprise at least 17% of the genome and are rapidly evolving compared to other Coleoptera, and high levels of nucleotide diversity in rapidly growing pest populations. Adaptations to plant feeding are evident in gene expansions and differential expression of digestive enzymes in gut tissues, as well as expansions of gustatory receptors for bitter tasting. Surprisingly, the suite of genes involved in insecticide resistance is similar to other beetles. Finally, duplications in the RNAi pathway might explain why Leptinotarsa decemlineata has high sensitivity to dsRNA. The L. decemlineata genome provides opportunities to investigate a broad range of phenotypes and to develop sustainable methods to control this widely successful pest