Biology subjects

Zych, M.

Publications and source records attributed to Zych, M..

6 recordsLinked to original sources

bioRxiv2026

Exotic catenulid flatworms (Platyhelminthes, Catenulida) and where to find them in a temperate climate - a field study in a botanic garden

Catenulids are free-living flatworms, common in eutrophic freshwaters such as ponds, ditches, or peatbogs, with most of the diversity described from tropical regions to date. Although the majority of the species have been described from warmer climates, most molecular studies have been done on specimens from temperate zones in Europe. We addressed this gap by sampling for exotic species in localities available in a temperate climate. In this study, we investigated catenulid diversity in the greenhouses at the University of Warsaw Botanic Garden and recorded two species known only from tropical areas (Stenostomum paraguayense and Suomina evelinae) and one exotic species recorded previously from a greenhouse in Poland (Stenostomum corderoi). Additionally, in the latter species, we provide evidence for environmentally induced coloration of sensory pits, which has not been reported thus far. We placed the collected species on a phylogeny using barcoding of 18S, 28S, and COI genes and retrieved paraphyly of the family Catenulidae, with S. evelinae forming a sister group to the genus Paracatenula, and hence we propose a revision of its systematic position. In total, we recorded six species, including three with a wide cosmopolitan distribution (C. turgida, S. grande and S. tuberculosum), and provided sequences for five of them, three of which had no previous molecular records (S. paraguayense, S. evelinae and S. corderoi). Thus, we confirm that greenhouses represent an important source of exotic species for taxonomic work on microscopic invertebrates.

zoology↗

bioRxiv2024

Decidual natural killer cells promote extravillous trophoblast developmental pathways: evidence from trophoblast organoid co-cultures

The placenta an essential extraembryonic organ that supports the fetus throughout gestation. The interactions between the placenta and the maternal immune system during the first trimester have not been wholly characterized despite their close physical association and hemi-allogeneic relationship. The most abundant type of immune cell in the uterus in the first trimester is the decidual natural killer cell (dNK). Despite their name, dNKs play supportive roles during pregnancy by remodelling uterine spiral arteries. We present evidence suggesting that the matrix metalloproteinases (MMPs) that dNKs secrete to promote this remodelling also drive placental development. This study used a novel co-culture system of dNKs and trophoblast organoids, which are mini-organs representing two to three different cell types of the human placenta. We found that co-cultures for one week led to significant (p=0.020) increases in the organoid area. We also observed significant decreases in trophoblast stemness markers and upregulation of gene sets associated with extravillous trophoblast (EVT) development through bulk RNA sequencing and immunohistochemical examinations. These changes were accompanied by significant (p<0.001) increases in collagen subunit gene expression in the organoids, with simultaneous significant decreases (p<0.001) in the proportion of organoid area occupied by collagen as determined through Massons Trichrome. Cultures containing dNKs also contained significantly higher MMP1, 3, 9, and 10 levels in their culture media, each of which can break down collagen. These findings demonstrate that dNKs promote changes concordant with trophoblast differentiation towards EVTs and villous branching morphogenesis.

developmental biology↗

bioRxiv2020

Highly contiguous assemblies of 101 drosophilid genomes

Over 100 years of studies in Drosophila melanogaster and related species in the genus Drosophila have facilitated key discoveries in genetics, genomics, and evolution. While high-quality genome assemblies exist for several species in this group, they only encompass a small fraction of the genus. Recent advances in long read sequencing allow high quality genome assemblies for tens or even hundreds of species to be generated. Here, we utilize Oxford Nanopore sequencing to build an open community resource of high-quality assemblies for 101 lines of 95 drosophilid species encompassing 14 species groups and 35 sub-groups with an average contig N50 of 10.5 Mb and greater than 97% BUSCO completeness in 97/101 assemblies. These assemblies, along with detailed wet lab protocol and assembly pipelines, are released as a public resource and will serve as a starting point for addressing broad questions of genetics, ecology, and evolution within this key group.

evolutionary biology↗

bioRxiv2019

Characterization of the adaptation to visuomotor rotations in the muscle synergies space

The adaptation to visuomotor rotations is one of the most studied paradigms of motor learning. Previous literature has presented evidence of a dependency between the process of adaptation to visuomotor rotations and the constrains dictated by the workspace of the biological actuators, the muscles, and their co-activation strategies, modeled using muscle synergies analysis. To better understand this relationship, we asked a sample of healthy individuals (N =7) to perform two experiments aiming at characterizing the adaptation to visuomotor rotations in terms of rotations of the activation space of the muscle synergies during isometric reaching tasks. In both experiments, subjects were asked to adapt to visual rotations altering the position mapping between the force exerted on a fixed manipulandum and the movement of a cursor on a screen. In the first experiment subjects adapted to three different visuomotor rotation angles (30{degrees}, 40{degrees} and 50{degrees} clockwise) applied to the whole experimental workspace. In the second experiment subjects adapted to a single visuomotor rotation angle (45{degrees} clockwise) applied to eight different sub-spaces of the whole workspace, while also performing movements in the rest of the unperturbed workspace. The results from the first experiment confirmed the observation that visuomotor rotations induce rotations in the synergies activation workspace that are proportional to the visuomotor rotation angle. The results from the second experiment showed that rotations affecting limited sub-spaces of the whole workspace are adapted for by rotating only the synergies involved in the movement, with an angle proportional to the distance between the preferred angle of the synergy and the sub-space covered by the rotation. Moreover, we show that the activation of a synergy is only rotated when the sub-space covered by the visual perturbation is applied at the boundaries of workspace of the synergy. We found these results to be consistent across subjects, synergies and sub-spaces. Moreover, we found a correlation between synergies and muscle rotations further confirming that the adaptation process can be well described, at the neuromuscular level, using the muscle synergies model. These results provide information on how visuomotor rotations can be used to induce a desired neuromuscular response.

bioengineering↗

bioRxiv2018

Effect of temporal and spatial asymmetries to the neuromuscular control of the lower limbs during stationary cycling

Motor adaptations are useful for studying the way in which the lower limbs are controlled by the brain. However, motor adaptation paradigms for the lower limbs are typically based on locomotion tasks, where the necessity of maintaining postural stability is the main driver of adaptation and could possibly mask other underlying processes. In this study we investigated whether small temporal or spatial asymmetries can trigger motor adaptations during stationary cycling, where stability is not directly compromised. Fourteen healthy individuals participated in two experiments: in one of the experiments the angle between the crank arms of the pedals was altered by 10{degrees} to induce a temporal asymmetry; in the other the length of the right pedal was shortened by 2.4 cm to induce a spatial asymmetry. We recorded the acceleration of the crank arms and the EMG signals of 16 muscles (8 per leg). The analysis of the accelerometer data was used to investigate the presence of motor adaptations. Muscle synergy analysis was performed on each side to quantify changes in neuromuscular control. We found that feedforward motor adaptations are present in response to temporal asymmetries and are obtained by progressively shifting the activation patterns of two synergies on the right leg. Spatial asymmetries appear to trigger a feedback-driven response that does not present an aftereffect and is not consistent with a motor adaptation. This response is characterized by a step-like decrease in activity in the right gastrocnemius when the asymmetry is present and likely reflects the altered task demands.\n\nNew and NoteworthyThe processes driving lower limb motor adaptations are not fully clear, and previous research appears to indicate that adaptations are mainly driven by stability. Here we show that lower limb adaptations can be obtained also in the absence of an explicit balance threat. We also show that adaptations are present also when kinematic error cannot be compensated for, suggesting the presence of intrinsic error measures regulating the timing of activation of the two legs.

neuroscience↗

bioRxiv2018

Consistent visuomotor adaptations and generalizations can be achieved through different rotations of robust motor modules

Humans have a remarkable ability to modify their motor commands in response to alterations in the environment. These motor commands are thought to be adaptively tuned by combining different motor primitives, a characteristic that allows for adaptations to be generalized also to relevant untrained scenarios. A complementary theory of motor primitives has shown that natural movements can be described by the combination of relatively invariant sets of muscle synergies. Synergistic structures have been shown to be maintained and tuned during motor adaptations. Here we studied the influence of synergistic organization of movement at the muscular level on the way in which adaptations to a 45{degrees} clockwise visuomotor rotation are achieved and generalized. We confirm that adaptation is achieved by tuning a set of robust muscle synergies and we show that the same biomechanical adaptation can be achieved by differentially tuning the same synergies. We demonstrate that this differential tuning ...

neuroscience↗