Biology subjects

Stopka, P.

Publications and source records attributed to Stopka, P..

4 recordsLinked to original sources

bioRxiv2023

The longer the better: longer acrosomes contain more proteins involved in sperm-egg interactions

Speciation and sperm competition have been shown to be the major driving forces for sperm morphology variation, swimming velocity and metabolism. We used light microscopy to measure sperm traits and nLC-MS/MS to detect proteomic variation in three species of rodents - promiscuous Apodemus flavicollis, less promiscuous Microtus arvalis, and the least promiscuous Mus musculus musculus. We show that the length of sperm apical hook containing the acrosome is the most variable trait and that this variation is reflected by proteomes on interspecific and intraspecific levels. Thus, we provide potential markers of selection such as Ldhc (in Mus and Apodemus) for long acrosomes which is a gene coding L-lactate dehydrogenase that is involved in sperm motility and Spaca1, which is important in sperm-oocyte fusion), and e.g. Mup17 for short acrosomes - a gene coding a Major urinary protein that likely chelates lipophilic compounds after spermiogenesis. In short, longer acrosomes are characteristic of proteins involved in fertilisation and gluconeogenesis, while shorter acrosomes contain more cytoskeletal proteins important for spermiogenesis. For the first time, we demonstrate that there is an innate and evolvable variability in sperm morphology and corresponding proteomes within species that can be driven by sperm competition to species-specific reproductive optima. Summary statementWe show that interspecific and intraspecific variation in sperm morphology traits are detectable on proteomic level thus providing markers of selection due to sperm competition.

cell biology↗

bioRxiv2023

The rules of sex and strain: deciphering the chemical language of inbred and wild mouse conspecific scents

In most mammals, conspecific chemosensory communication relies on semiochemical release within complex bodily secretions and subsequent stimulus detection by the vomeronasal organ (VNO). Urine, a rich source of ethologically relevant chemosignals, conveys detailed information about sex, social hierarchy, health and reproductive state, which becomes accessible to a conspecific via vomeronasal sampling. So far, however, numerous aspects of social chemosignaling along the vomeronasal pathway remain unclear. Moreover, since virtually all research on vomeronasal physiology is based on secretions derived from inbred laboratory mice, it remains uncertain whether such stimuli provide a true representation of potentially more relevant cues found in the wild. Here, we combine a robust low-noise VNO activity assay with comparative molecular profiling of sex- and strain-specific mouse urine samples from two inbred laboratory strains as well as from wild mice. With comprehensive molecular portraits of these secretions, VNO activity analysis now enables us to (i) assess whether and, if so, how much sex- / strain-selective "raw" chemical information in urine is accessible via vomeronasal sampling; (ii) identify which chemicals exhibit sufficient discriminatory power to signal an animals sex, strain, or both; (iii) determine the extent to which wild mouse secretions are unique; and (iv) analyze whether vomeronasal response profiles differ between strains. We report both sex- and, in particular, strain-selective VNO representations of chemical information. Within the urinary secretome, both volatile compounds and proteins exhibit sufficient discriminative power to provide sex- and strain-specific molecular fingerprints. While total protein amount is substantially enriched in male urine, females secrete a larger variety at overall comparatively low concentrations. Surprisingly, the molecular spectrum of wild mouse urine does not dramatically exceed that of inbred strains. Finally, vomeronasal response profiles differ between C57BL/6 and BALB/c animals, with particularly disparate representations of female semiochemicals.

neuroscience↗

bioRxiv2022

Perioral secretions enable complex social signaling in African mole-rats (genus Fukomys)

Subterranean common mole-rats of the genus Fukomys (family Bathyergidae) live in large cooperatively-breeding families. Odor cues have been hypothesized to importantly mediate social behaviors in the underground ecotope, but only little is known about the role of olfactory signaling in burrowing mammals. Here we characterize the so far neglected perioral glands of Fukomys and other African mole-rats as an important source of olfactory social information. Histology demonstrates these structures to be derived sebaceous glands that are developed regardless of sex and reproductive status. However, gland activity is higher in Fukomys males, leading to sexually dimorphic patterns of stain and clotting of the facial pelage. Behavioral assays revealed that conspecifics prefer male but not female perioral swabs over scent samples from the back fur and that male sebum causes similar attraction as anogenital scent, a known source of social information in Fukomys. Finally, we assessed volatile compounds in the perioral sebum of the giant mole-rat (Fukomys mechowii) via GCxGC-MS-based metabolomic profiling. Volatiles displayed pronounced sex-specific signatures but also allowed to differentiate between intrasexual reproductive status groups. These different lines of evidence suggest that mole-rat perioral glands provide complex odor signals that play a crucial role in social communication.

zoology↗

bioRxiv2020

Phenotypic and clonal stability of antigen-inexperienced memory-like T cells across the genetic background, hygienic status, and aging

Antigen-inexperienced memory-like T (AIMT) cells are functionally unique T cells representing one of the two largest subsets of murine CD8+ T cells. However, differences between laboratory inbred strains, insufficient data from germ-free mice, a complete lack of data from feral mice, and unclear relationship between AIMT cells formation during aging represent major barriers for better understanding of their biology. We performed a thorough characterization of AIMT cells from mice of different genetic background, age, and hygienic status by flow cytometry and multi-omics approaches including analyses of gene expression, TCR repertoire, and microbial colonization. Our data showed that AIMT cells are steadily present in mice independently of their genetic background and hygienic status. Despite differences in their gene expression profiles, young and aged AIMT cells originate from identical clones. We identified that CD122 discriminates two major subsets of AIMT cells in a strain-independent manner. Whereas thymic CD122LOW AIMT cells (innate memory) prevail only in young animals with high thymic IL-4 production, peripheral CD122HIGH AIMT cells (virtual memory) dominate in aged mice. Co-housing with feral mice changed the bacterial colonization of laboratory strains, but had only minimal effects on the CD8+ T-cell compartment including AIMT cells.

immunology↗