Loss Of Motility Research Articles

Responses to transient receptor potential (TRP) channel agonists inChlamydomonas reinhardtii

ABSTRACTPungent substances, such as capsaicin and gingerol, activate the transient receptor potential (TRP)-V1 channel and affect the feeding behaviors of animals. To gain insight into how living organisms have acquired a sense for pungent substances, we explored the response to TRP agonists in a protist, Chlamydomonas reinhardtii. When capsaicin or gingerol was applied to wild-type cells, they became immotile, with flagella detaching from the cell body. The degree of deflagellation was nearly halved in a mutant defective in the TRP channel ADF1. Deflagellation in the adf1 mutant was inhibited further by Ruthenium Red, indicating ADF1 and another TRP channel are involved in the deflagellation response. The response to capsaicin and gingerol was not inhibited by TRPV1-specific blockers such as 4-(3-Chloro-2-pyridinyl)-N-[4-(1,1-dimethylethyl)phenyl]-1-piperazinecarboxamide (BCTC) and capsazepine. When capsaicin or gingerol was applied to wild-type cells in the presence of Ruthenium Red, a large proportion lost motility while flagella remained attached, suggesting that flagella stop contributing to motility, at least in part, through a TRP-channel-independent pathway. These results indicate that pungent compounds such as capsaicin and gingerol induce loss of flagellar motility and flagellar detachment in C. reinhardtii cells.

Use of Glass-Forming Water–Salt Systems for Preparing Human Sperm to Hypothermic Semen Preservation

A protectant for hypothermic preservation of human sperm based on glass-forming water–salt systems of vital metals (magnesium, zinc, and calcium) was developed for the first time. The method of sperm preservation without preliminary washing of seminal plasma is proposed, which retains the sperm viability and sperm motility parameters comparable to the values of native sperm. The proposed protectant and method of preparing human sperm for hypothermic storage at the first stage help to slow down the metabolism as evidenced by the complete loss of sperm motility and maintenance of the nearly 100% viability of the studied sperm. Once the protectant was removed, sperm motility is restored up to 90–100% compared to the indices of native sperm.

Comparative Evaluation of Different Methods for Assessing Stallion Sperm Membrane Integrity

Comparative evaluation of three different methods for assessing stallion sperm-membrane integrity, including the eosin staining technique, the fluorochrome staining (SYBR-14 + PI) method, and the hypo-osmotic test, has been made in order to reveal the most efficient method of measurement for this item. The stallion sperm showed high coefficients of correlation between sperm motility and intact membrane proportion with all the methods of measurement. The best coincidence result was attained with the eosin staining technique, assessed by a correlation coefficient of 0.91. This technique has the advantages of simplicity, accessibility, and efficiency. Accurate assessment requires performing a method of subtracting a number of unstained damaged sperm cells, which are nonfunctional, from a total number of unstained spermatozoa. The proportion of motile sperm does not coincide with the proportion of sperm intact membranes during the stallion-semen storage process according to all the methods of measurement. A significant sperm count remains with intact cell membranes at the loss of total motility at the end of a storage process. This indicates that the sperm cells become immotile because of layout of the energetic material in flagellar mitochondria, which is not associated with membrane integrity. Therefore, it is recommended to assess the stallion sperm membranes with the use of fresh or thawed sperm. It is suggested to use assessment of membrane integrity in clarifying the sperm motility, particularly, in especially doubtful cases.

Excess iodine impairs spermatogenesis by inducing oxidative stress and perturbing the blood testis barrier

Approximately 2 billion people worldwide are susceptible to iodine deficiency. Iodine deficiency has largely been tackled by iodine fortification in salt; however indiscriminate use of iodine raises the risk of iodine toxicity. In this study, we aimed to investigate the molecular mechanisms underlying adverse effect of excess iodine on spermatogenesis. Sprague Dawley (SD) rats were orally administered with 0.7 mg potassium iodide (KI)/100 g Bw and 3.5 mg potassium iodide (KI)/100 g Bw for a period of 60 days. This resulted in significant loss of sperm count and motility. Molecular investigations provided evidence for the generation of oxidative stress with high SOD levels, reduced Nrf2, HO-1 and increased NF-kB and Follistatin. Further investigations showed increased apoptosis evidenced by reduced expression of anti-apoptotic (BCL-2, Survivin), increased expression of pro-apoptotic (Bid, Bax) markers, and increased expression of p53 and other modulators/effectors of apoptosis (cytochrome c, cleaved PARP, caspase3 and caspase9). Analysis of the blood testis barrier proteins showed reduced expression of tight junction (JAM-A, Tricellulin), ectoplasmic specialization (Integrin- β1), adherens junction (N-Cadherin, E-cadherin, β-catenin) proteins, and reduced expression of other junction protein coding genes (Claudin1, Claudin 5, Occludin, ZO-1, Testin, Fibronectin, CAR-F). Focal adhesion kinase (FAK) and key regulators of spermatogenesis (c-Kit receptor, androgen receptor) were also parallelly decreased. Further investigation showed reduced expression of germ cell proliferation and differentiation markers (PCNA, Cyclin D1, c-Kit, Cdk-4). These findings collectively explain the loss of spermatogenesis under excess iodine conditions. In conclusion, excess iodine causes loss of spermatogenesis by inducing oxidative stress and disrupting the blood testis barrier and cytoskeleton.

Schisandra chinensis water extract protects ethanol-induced neurotoxicity in Caenorhabditis elegans.

The protective effect of Schisandra chinensis water extract (SWE) on ethanol-induced neurotoxicity in Caenorhabditis elegans and the underlying mechanism were investigated. Young worms were exposed to ethanol or a mixture of ethanol and SWE for 24hr. Locomotion ability, tissue ethanol concentration, free radical content, antioxidant enzyme activity, lifespan, and expression of key dopaminergic nervous system-related genes were evaluated. Ethanol affected the motion ability of worms and shortened their lifespan. Ethanol intake increased the tissue ethanol concentration, resulting in redox imbalance, and dopamine release and accumulation. SWE alleviated motility loss of C. elegans and extended their lifespan. It reduced the tissue ethanol concentration and free radical content, likely because it alleviated oxidative stress. Finally, SWE inhibited continuous dopamine excitement. These results suggest that SWE plays a protective role in dopaminergic neurons. It can be used to treat ethanol-induced neurotoxicity, and to investigate its potential mechanism. PRACTICAL APPLICATIONS: Schisandra chinensis is a traditional functional food that has protective effects on the liver and brain. Although S. chinensis is found in some anti-alcohol products, the effects of S. chinensis on neurological and behavioral disorders caused by alcohol are rarely reported. The manuscript explored the protective effect of SWE on ethanol-induced nerve injury in Caenorhabditis elegans, and we preliminarily discussed the underlying mechanism. The results suggested that SWE can alleviate ethanol-induced neurotoxicity. Meanwhile, the results provide a theoretical basis for better use of S. chinensis to develop products to antagonize the side effects of alcohol. In addition, the method of using C. elegans model to evaluate the protective effect of S. chinensis on ethanol-induced nerve injury can provide practical reference for the screening and utilization of other plant functional components.

An ECF41 family σ factor controls motility and biogenesis of lateral flagella in Azospirillum brasilense Sp245.

ECF41 is a large family of bacterial extra-cytoplasmic function (ECF) σ factors. Their role in bacterial physiology or behavior, however, is not known. One of the 10 ECF σ factors encoded in the genome of Azospirillum brasilense Sp245, RpoE10, exhibits characteristic features of the typical ECF41-type σ factors. Inactivation of rpoE10 in A. brasilense Sp245 led to an increase in motility that could be complemented by the expression of rpoE10 By comparing the number of lateral flagella, transcriptome and proteome of A. brasilense Sp245 with its rpoE10::km mutant, we show here that this ECF41-type σ factor is involved in the negative regulation of swimming motility and biogenesis of lateral flagella of A. brasilense Sp245. The genome of A. brasilense Sp245 also encodes two OmpR-type regulators (LafR1 and LafR2), and three flagellins including Laf1, the major flagellin of lateral flagella. Elevated levels of laf1 transcripts and Laf1 protein in the rpoE10::km mutant indicated that RpoE10 negatively regulates the expression of Laf1. The elevated level of LafR1 in the rpoE10::km mutant indicated that LafR1 is also negatively regulated by RpoE10. The loss of motility and Laf1 in the lafR1::km mutant, complemented by lafR1 expression, showed that LafR1 is a positive regulator of Laf1 and motility in A. brasilense In addition, upregulation of laf1::lacZ and lafR1::lacZ fusions by RpoE10, and downregulation of the laf1::lacZ fusion by LafR1 suggests that RpoE10 negatively regulates swimming motility and the expression of LafR1 and Laf1. However, LafR1 positively regulates the swimming motility and Laf1 expression.Importance: Among extra-cytoplasmic function (ECF) σ factors, ECF41-type σ factors are unique due to the presence of a large C-terminal extension in place of a cognate anti- σ factor, which regulates their activity. Despite wide distribution and abundance in bacterial genomes, their physiological or behavioural roles are not known. We show here an indirect negative role of an ECF41-type of σ factor in the expression of lateral flagellar genes and motility in A.brasilense This study suggests that the motility of A. brasilense might be controlled by a regulatory cascade involving RpoE10, an unknown repressor, LafR1 and lateral flagellar genes including Laf1.

Seminal Plasma Proteome as an Indicator of Sperm Dysfunction and Low Sperm Motility in Chickens

Molecular mechanisms underlying sperm motility have not been fully explained, particularly in chickens. The objective was to identify seminal plasma proteins associated with chicken sperm motility by comparing the seminal plasma proteomic profile of roosters with low sperm motility (LSM, n = 4) and high sperm motility (HSM, n = 4). Using a label-free MS-based method, a total of 522 seminal plasma proteins were identified, including 386 (∼74%) previously reported and 136 novel ones. A total of 70 differentially abundant proteins were defined, including 48 more-abundant, 15 less-abundant, and seven proteins unique to the LSM group (specific proteins). Key secretory proteins like less-abundant adhesion G-protein coupled receptor G2 (ADGRG2) and more-abundant serine peptidase inhibitor Kazal-type 2 (SPINK2) in the LSM suggested that the corresponding secretory tissues played a crucial role in maintaining sperm motility. Majority (80%) of the more-abundant and five specific proteins were annotated to the cytoplasmic domain which might be a result of higher plasma membrane damage and acrosome dysfunction in LSM. Additionally, more-abundant mitochondrial proteins were detected in LSM seminal plasma associated with lower spermatozoa mitochondrial membrane potential (ΔΨm) and ATP concentrations. Further studies showed that the spermatozoa might be suffering from oxidative stress, as the amount of spermatozoa reactive oxygen species (ROS) were largely enhanced, seminal malondialdehyde (MDA) concentrations were increased, and the seminal plasma total antioxidant capacity (T-AOC) were decreased. Our study provides an additional catalogue of chicken seminal plasma proteome and supports the idea that seminal plasma could be as an indicator of spermatozoa physiology. More-abundant of acrosome, mitochondria and sperm cytoskeleton proteins in the seminal plasma could be a marker of sperm dysfunction and loss of motility. The degeneration of spermatozoa caused by the reduced seminal T-AOC and enhanced oxidative stress might be potential determinants of low sperm motility. These results could extend our understanding of sperm motility and sperm physiology regulation.

Repellency and mortality effects of sunscreens on the shrimp Palaemon varians: Toxicity dependent on exposure method

Contamination by sunscreens has become a serious environmental problem due to the increasing use of these products in coastal regions. Their complex chemical composition supposes an input of different chemical compounds capable of producing toxic effects and repelling organisms. The aim of the current study was to experimentally check the repellency of three commercial sunscreens [A (lotion), B (gel) and C (milk spray)] by assessing the escape (displacement towards areas with lower sunscreen levels) of the estuarine shrimp Palaemon varians exposed (4 h) to a gradient (0-300 mg/L) of the sunscreens in a heterogeneous non-forced exposure scenario. Additionally, mortality and immobility (72 h) were checked in a traditional forced exposure scenario. Considering that the toxicity of sunscreens is a little controversial regarding their chemical availability in the medium, two different methods of sunscreen solubilisation were tested: complete homogenization and direct immersion. Very low mortality was observed in the highest concentration of sunscreens A and C applied by direct immersion; however, for sunscreen B, the main effect was the loss of motility when homogenization was applied. Repellency was evidenced for two sunscreens (A and B) applied by direct immersion. The homogenization in the medium seemed to lower the degree of repellency of the sunscreens, probably linked to the higher viscosity in the medium, preventing the motility of shrimps. By integrating both short-term responses (avoidance and mortality/immobility), the PID (population immediate decline) calculated showed that avoidance might be the main factor responsible for the reduction of the population at the local scale.

SCO-Spondin Defects and Neuroinflammation Are Conserved Mechanisms Driving Spinal Deformity across Genetic Models of Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) affects 3% to 4% of children between the ages of 11 and 18 [1, 2]. This disorder, characterized by abnormal three-dimensional spinal curvatures that typically develop during periods of rapid growth, occurs in the absence of congenital vertebral malformations or neuromuscular defects [1]. Genetic heterogeneity [3] and a historical lack of appropriate animal models [4] have confounded basic understanding of AIS biology; thus, treatment options remain limited [5, 6]. Recently, genetic studies using zebrafish have linked idiopathic-like scoliosis to irregularities in motile cilia-mediated cerebrospinal fluid flow [7-9]. However, because loss of cilia motility in human primary ciliary dyskinesia patients is not fully associated with scoliosis [10, 11], other pathogenic mechanisms remain to be determined. Here, we demonstrate that zebrafish scospondin (sspo) mutants develop late-onset idiopathic-like spinal curvatures in the absence of obvious cilia motility defects. Sspo is a large secreted glycoprotein functionally associated with the subcommissural organ and Reissner's fiber [12]-ancient and enigmatic organs of the brain ventricular system reported to govern cerebrospinal fluid homeostasis [13, 14], neurogenesis [12, 15-18], and embryonic morphogenesis [19]. We demonstrate that irregular deposition of Sspo within brain ventricles is associated with idiopathic-like scoliosis across diverse genetic models. Furthermore, Sspo defects are sufficient to induce oxidative stress and neuroinflammatory responses implicated in AIS pathogenesis [9]. Through screening for chemical suppressors of sspo mutant phenotypes, we also identify potent agents capable of blocking severe juvenile spine deformity. Our work thus defines a new preclinical model of AIS and provides tools to realize novel therapeutic strategies.

Wampa is a dynein subunit required for axonemal assembly and male fertility in Drosophila

In cilia and flagella, dyneins form complexes which give rise to the inner and outer axonemal arms. Defects in the dynein arms are the leading cause of primary ciliary dyskinesia (PCD), which is characterized by chronic respiratory infections, situs inversus, and sterility. While the pathological features associated with PCD are increasingly well characterized, many of the causative genetic lesions remain elusive. Using Drosophila, here we analyze genetic requirements for wampa (wam), a previously uncharacterized component of the outer dynein arm. While homozygous mutant animals are viable and display no morphological defects, loss of wam results in complete male sterility. Ultrastructural analysis further reveals that wam mutant spermatids lack the axonemal outer dynein arms, which leads to a complete loss of flagellar motility. In addition to a role in outer dynein arm formation, we also uncover other novel microtubule-associated requirements for wam during spermatogenesis, including the regulation of mitochondrial localization and the shaping of the nuclear head. Due to the conserved nature of dyneins, this study advances our understanding of the pathology of PCD and the functional role of dyneins in axoneme formation and other aspects of spermatogenesis.

Specific Cell-Surface Glycans on Phagocytes Mediate Binding of Pseudomonas aeruginosa

Abstract Pseudomonas aeruginosa is a Gram-negative bacterium that, as an opportunistic pathogen, substantially contributes to high morbidity and mortality rates in susceptible individuals such as those with cystic fibrosis or neutropenia. Previous studies identified that the downregulation or loss of bacterial flagellar motility, typically observed within chronic infections, enables bacteria to evade interactions with phagocytic cells that would result in phagocytic uptake. Our recent work demonstrated that exogenous addition of a negatively charged lipid, PIP3, induces binding and phagocytosis of non-motile strains of P. aeruginosa. Based on this work, we hypothesized that the engagement of P. aeruginosa by host innate cells, and subsequent phagocytosis, is mediated by motility-dependent interactions with cell-surface polyanions. We now report that endogenous polyanionic N-linked glycans and heparan sulfate mediate bacterial binding of P. aeruginosa by human monocytic cells. These specific cell-surface interactions result in P. aeruginosa phagocytosis, bacterial type 3 secretion system (T3SS)-mediated cellular intoxication and the IL-1β inflammatory response of the host innate immune cells. Concomitantly, inhibition of host cell N-glycan synthesis reduces T3SS-mediated cytotoxicity and the IL-1β response induced by the bacteria. Importantly, the bacterial interactions with the glycans were motility-dependent and could be recapitulated with purified, immobilized glycans. Therefore, this work describes novel interactions of P. aeruginosa with specific phagocyte cell-surface glycans that modulate relevant host innate immune responses to the bacteria, including phagocytosis, inflammation and cytotoxicity.

Distinct Contributions of CD18 Integrins for Binding and Phagocytic Internalization of Pseudomonas aeruginosa

Phagocytosis is the key mechanism for host control of Pseudomonas aeruginosa, a motile Gram-negative, opportunistic bacterial pathogen which frequently undergoes adaptation and selection for traits that are advantageous for survival. One such clinically relevant adaptation is the loss of bacterial motility, observed within chronic infections, that is associated with increased antibiotic tolerance and phagocytic resistance. Previous studies using phagocytes from a leukocyte adhesion deficiency type 1 (LAD-I) patient identified CD18 as a putative cell surface receptor for uptake of live P. aeruginosa However, how bacterial motility alters direct engagement with CD18-containing integrins remains unknown. Here we demonstrate, with the use of motile and isogenic nonmotile deletion mutants of two independent strains of P. aeruginosa and with CRISPR-generated CD18-deficient cell lines in human monocytes and murine neutrophils, that CD18 expression facilitates the uptake of both motile and nonmotile P. aeruginosa However, unexpectedly, mechanistic studies revealed that CD18 expression was dispensable for the initial attachment of the bacteria to the host cells, which was validated with ectopic expression of complement receptor 3 (CR3) by CHO cells. Our data support that surface N-linked glycan chains (N-glycans) likely facilitate the initial interaction of bacteria with monocytes and cooperate with CD18 integrins in trans to promote internalization of bacteria. Moreover, talin-1 and kindlin-3 proteins promote uptake, but not binding, of P. aeruginosa by murine neutrophils, which supports a role for CD18 integrin signaling in this process. These findings provide novel insights into the cellular determinants for phagocytic recognition and uptake of P. aeruginosa.

Knockout of serine-rich single-pass membrane protein 1 (Ssmem1) causes globozoospermia and sterility in male mice†.

Globozoospermia (sperm with an abnormally round head shape) and asthenozoospermia (defective sperm motility) are known causes of male infertility in human patients. Despite many studies, the molecular details of the globozoospermia etiology are still poorly understood. Serine-rich single-pass membrane protein 1 (Ssmem1) is a conserved testis-specific gene in mammals. In this study, we generated Ssmem1 knockout (KO) mice using the CRISPR/Cas9 system, demonstrated that Ssmem1 is essential for male fertility in mice, and found that SSMEM1 protein is expressed during spermatogenesis but not in mature sperm. The sterility of the Ssmem1 KO (null) mice is associated with globozoospermia and loss of sperm motility. To decipher the mechanism causing the phenotype, we analyzed testes with transmission electron microscopy and discovered that Ssmem1-disrupted spermatids have abnormal localization of Golgi at steps eight and nine of spermatid development. Immunofluorescence analysis with anti-Golgin-97 to label the trans-Golgi network, also showed delayed movement of the Golgi to the spermatid posterior region, which causes failure of sperm head shaping, disorganization of the cell organelles, and entrapped tails in the cytoplasmic droplet. In summary, SSMEM1 is crucial for intracellular Golgi movement to ensure proper spatiotemporal formation of the sperm head that is required for fertilization. These studies and the pathway in which SSMEM1 functions have implications for human male infertility and identifying potential targets for nonhormonal contraception.

Molecular dynamics of the membrane interaction and localisation of prodigiosin

The tripyrrolic antibiotic prodigiosin causes diverse reactions on its targets like energy spilling, membrane leakage, loss of motility and phototoxicity. It has bacteriostatic, bactericidal, anti-fungal, anti-cancer and immunosuppressive properties. Most of the functions suggest the role of prodigiosin in membrane disruption but the exact mechanism remains unknown. A molecular dynamics study was performed to understand the interactions of prodigiosin with the membrane. It was seen that prodigiosin from the solvent enters the membrane immediately either individually or as small clusters. Prodigiosin clusters with more than eight molecules do not appear to enter the membrane. Upon entry, the molecules orient themselves along the membrane-water interface with the pyrrole rings interacting with lipid head groups and with water. This orientation is stabilised by hydrogen bonding and hydrophobic interactions. The presence of prodigiosin molecules in the membrane changes the local lipid architecture and reduces the solvent accessibility of the membrane. The membrane fluidity, thickness or area per lipid head are largely unaffected. This suggests that prodigiosin could cause most damage in the vicinity of a membrane protein and thus could also explain the reason for varied effects on the targets.

Hypoxia Inducible Factor-1α in Osteochondral Tissue Engineering.

Damage to osteochondral (OC) tissues can lead to pain, loss of motility, and progress to osteoarthritis. Tissue engineering approaches offer the possibility of replacing damaged tissues and restoring joint function; however, replicating the spatial and functional heterogeneity of native OC tissue remains a pressing challenge. Chondrocytes in healthy cartilage exist in relatively low-oxygen conditions, while osteoblasts in the underlying bone experience higher oxygen pressures. Such oxygen gradients also exist in the limb bud, where they influence OC tissue development. The cellular response to these spatial variations in oxygen pressure, which is mediated by the hypoxia inducible factor (HIF) pathway, plays a central role in regulating osteo- and chondrogenesis by directing progenitor cell differentiation and promoting and maintaining appropriate extracellular matrix production. Understanding the role of the HIF pathway in OC tissue development may enable new approaches to engineer OC tissue. In this review, we discuss strategies to spatially and temporarily regulate the HIF pathway in progenitor cells to create functional OC tissue for regenerative therapies.Impact statementStrategies to engineer osteochondral (OC) tissue are limited by the complex and varying microenvironmental conditions in native bone and cartilage. Indeed, native cartilage experiences low-oxygen conditions, while the underlying bone is relatively normoxic. The cellular response to these low-oxygen conditions, which is mediated through the hypoxia inducible factor (HIF) pathway, is known to promote and maintain the chondrocyte phenotype. By using tissue engineering scaffolds to spatially and temporally harness the HIF pathway, it may be possible to improve OC tissue engineering strategies for the regeneration of damaged cartilage and its underlying subchondral bone.

Functional activity of mitochondria associated with cytoskeleton stability in the HEK293

Mitochondria are dynamic cellular organelles that provide the biological energy to the cell. The dynamic property of the mitochondria is associated with the cytoskeleton network in the cell. However, relationship is no clear identified between cytoskeleton instability and the functional activity of mitochondria in cell. This study is designed to assess the dynamic properties of the mitochondria, and specifically to observe whether they are associated with the cytoskeleton stability for the mitochondria’s functional activityWe prepared the cytoskeleton stability regulation model with the HEK293 cell line by vinorelbine which microtubule distributor and the cytoskeleton stabilizer as a taxol. We determined the optimal concentration of vinorelbine and taxol though cytotoxicity assay with the HEK293 cell line. Then, we analyzed the functional activity of the mitochondria depending on the microtubule instability. First, we undertook an observation of cell morphology under distributor or stabilizer. We analyzed the metabolic activity of the cell with the CCK and ATP productive assay. And we performed confocal live imaging for observation of mitochondria morphology in the cytoskeleton instable cells. We performed the reverse transcription polymer chain reaction for analysis of the mRNA expression in the cytoskeleton’s instable cells with Tau protein, Glut1 and GAPDH as the normalization marker.The vinorelbine treated cell shows dramatically changes with cell morphology compared with control. And the vinorelbine treated cell significantly increases the fission ratios of the mitochondria compared with the original form based on the confocal images. Microtubule instable cells significantly decreased the ATP’s productive ratios and the functional activity of the mitochondria. However, the cytoskeleton stabilizer as a taxol(0.01uM) combined with vinorelbine treated cells, shows recovery effect to cell morphology recovery effect like the control cells that were only treated with vinorebine. And taxol that was combined with vinorelbine treated cells significantly increased bioenergy product ratios and its functional activity compared with the vinorelbine.In conclusion, the dynamic mitochondrial motility might influence the microtubule stability in cells. Because, vinorelbine‐treated cells displayed destabilized microtubules, loss of motility and fission formation of mitochondria. And loss motility of the mitochondria shows poor ATP productive ratios, resulting in a phenotype like that observed in the cells. This data suggests that functional activity of the mitochondria is associated with the microtubule stability in the cells. And microtubule stabilizer has a possibility to recovery functional activity in the microtubule instable cell like aging process. This finding can be applying to understand the mechanism of aging.Support or Funding InformationThis research was supported by the University Innovation Support Project (UISP) through the National Research Foundation (NRF) funded by MEST(Project No. 20190104)CCK analysis(A) and cell morphology(B) of NaB and Taxol treated cellsFigure 1ATP productive ratios(A) and fission form of mitochondria(B) of cellsFigure 2

Flagellar motility mediates early-stage biofilm formation in oligotrophic aquatic environment.

Flagellar motility enables resource acquisition and noxious substance evasion, underpinning imperative ecological processes in aquatic environments. Yet the underlying mechanism that links flagellar motility with surface attachment and thereby biofilm formation, especially in conditions of limited resource availability, remains elusive. Here, we present experimental and modeling evidence to unveil bacterial motility and biofilm formation under nutrient-limited stresses with Pseudomonas aeruginosa (WT) and its nonflagellated isogenic mutant (ΔfliC) as model bacteria. Results revealed that boosted flagellar motility of WT strain promoted biofilm initialization to a peak value of 0.99×107cells/cm2 at 1/50 dilution after 20min incubation. We hypothesized that bacteria can invoke instant motility acceleration for survival confronting nutrient-limited stress, accompanied by optimized chemotactic foraging through sensing ambient chemical gradients. Accordingly, accelerated cell motility in oligotrophic environment created increased cell-cell and cell-surface interactions and thereof facilitated biofilm initialization. It was confirmed by the consistence of modeling predictions and experimental results of cell velocity and surface attachment. With the development of biofilm, promotion effect of flagellar motility responding to nutrient deprivation-stress faded out. Instead, loss of motility profiting increased growth rates and extracellular protein excretion, associated with an enhancement of biofilm development for the mutant in oligotrophic aquatic environment. For both strains, nutrient limitation evidently reduced planktonic cell propagation as expected. Our results offer new insights into the mechanical understanding of biofilm formation shaped by environmental stresses and associating biological responses.

Cell Size, Mechanical Tension, and GTPase Signaling in the Single Cell.

Cell polarization requires redistribution of specific proteins to the nascent front and back of a eukaryotic cell. Among these proteins are Rac and Rho, members of the small GTPase family that regulate the actin cytoskeleton. Rac promotes actin assembly and protrusion of the front edge, whereas Rho activates myosin-driven contraction at the back. Mathematical models of cell polarization at many levels of detail have appeared. One of the simplest based on "wave-pinning" consists of a pair of reaction-diffusion equations for a single GTPase. Mathematical analysis of wave-pinning so far is largely restricted to static domains in one spatial dimension. Here, we extend the analysis to cells that change in size, showing that both shrinking and growing cells can lose polarity. We further consider the feedback between mechanical tension, GTPase activation, and cell deformation in both static, growing, shrinking, and moving cells. Special cases (spatially uniform cell chemistry, the absence or presence of mechanical feedback) are analyzed, and the full model is explored by simulations in 1D. We find a variety of novel behaviors, including "dilution-induced" oscillations of Rac activity and cell size, as well as gain or loss of polarization and motility in the model cell.

Multiscale Process Modelling in Translational Systems Biology of Leishmania major: A Holistic view

Present work aims to utilize systems biology and molecular modelling approach to understand the inhibition kinetics of Leishmania major GLO I and identifying potential hit followed by their validation through in vitro and animal studies. Simulation of GLO I inhibition has shown to affect reaction fluxes of almost all reactions in the model that led to increased production of various AGEs and free radicals. Further, in vitro testing of C1 and C2, selected through molecular modelling revealed remarkable morphological alterations like size reduction, membrane blebbing and loss in motility of the parasite, however, only C1 showed better antileishmanial activity. Additionally, C1 showed apoptosis mediated leishmanicidal activity (apoptosis-like cell death) along with cell-cycle arrest at sub-G0/G1 phase and exhibited potent anti-leishmanial effect against intracellular amastigotes. Furthermore, decrease in parasite load was also observed in C1 treated BALB/c female mice. Our results indicate that C1 has healing effect in infected mice and effectively reduced the parasitic burden. Hence, we suggest C1 as a lead molecule which on further modification, may be used to develop novel therapeutics against Leishmaniasis.

Mass Spectrometry Reveals New Insights into the Production of Superoxide Anions and 4-Hydroxynonenal Adducted Proteins in Human Sperm.

The free-radical theory of male infertility suggests that reactive oxygen species produced by the spermatozoa themselves are a leading cause of sperm dysfunction, including loss of sperm motility. However, the field is overshadowed on several fronts, primarily because: i) the probes used to measure reactive oxygen species (ROS) are imprecise; and ii) many reports suggesting that oxygen radicals are detrimental to sperm function add an exogenous source of ROS. Herein, a more reliable approach to measure superoxide anion production by human spermatozoa based on MS analysis is used. Furthermore, the formation of the lipid-peroxidation product 4-hydroxynonenal (4-HNE) during in vitro incubation using proteomics is also investigated. The data demonstrate that neither superoxide anion nor other free radicals that cause 4-HNE production are related to the loss of sperm motility during incubation. Interestingly, it appears that many of the 4-HNE adducted proteins, found within spermatozoa, originate from the prostate. A quantitative SWATH analysis demonstrate that these proteins transiently bind to sperm and are then shed during in vitro incubation. These proteomics-based findings propose a revised understanding of oxidative stress within the male reproductive tract.