Clusters Of Vesicles Research Articles

α-Synuclein and biological membranes: the danger of loving too much.

The aberrant aggregation of α-Synuclein (αS), a disordered protein primarily localised at the neuronal synapses, is associated with a number of neurodegenerative disorders including Parkinson's disease (PD). The biological properties of αS are strictly connected with its ability to bind synaptic membranes under both physiological and pathological conditions. Here we overview the recent studies on the structural and biological properties of the membrane interaction by αS. The characterisation of this state is particularly challenging as the membrane binding of αS is weak, transient and features a considerable degree of conformational disorder. Advancements in this area have been achieved through combinations of nuclear magnetic resonance (NMR), super-resolution microscopy, cryo-EM and cellular biophysics. Current data clarified the central role of the equilibrium between ordered and disordered states of αS at the membrane surface, which regulates the membrane affinity, the aggregation into amyloid fibrils and the promotion of vesicle clustering. Recent results on toxic oligomeric species of αS also revealed common features in the membrane interaction of functional and aberrant forms of this protein. These findings therefore evidence the challenging nature of identifying suitable therapeutics to target the aberrant aggregation of αS in PD while leaving its normal physiological form unperturbed.

Rapid and reversible optogenetic silencing of synaptic transmission by clustering of synaptic vesicles

Acutely silencing specific neurons informs about their functional roles in circuits and behavior. Existing optogenetic silencers include ion pumps, channels, metabotropic receptors, and tools that damage the neurotransmitter release machinery. While the former hyperpolarize the cell, alter ionic gradients or cellular biochemistry, the latter allow only slow recovery, requiring de novo synthesis. Thus, tools combining fast activation and reversibility are needed. Here, we use light-evoked homo-oligomerization of cryptochrome CRY2 to silence synaptic transmission, by clustering synaptic vesicles (SVs). We benchmark this tool, optoSynC, in Caenorhabditis elegans, zebrafish, and murine hippocampal neurons. optoSynC clusters SVs, observable by electron microscopy. Locomotion silencing occurs with tauon ~7.2 s and recovers with tauoff ~6.5 min after light-off. optoSynC can inhibit exocytosis for several hours, at very low light intensities, does not affect ion currents, biochemistry or synaptic proteins, and may further allow manipulating different SV pools and the transfer of SVs between them.

Paraviral cutaneous manifestations associated to SARS-CoV-2 Omicron variant

Background The spreading of the SARS-CoV-2 Omicron variant is probably due to its increased transmissibility and ability to escape from neutralising antibodies. Cutaneous manifestations have been reported after infection with the Omicron strain, consisting mainly of generalised urticarial eruption and prickly heat rash, also known as miliaria, that can persist for several days. Here the impact of Omicron SARS-CoV-2 on skin was investigated. Methods The case series of 10 patients with SARS-CoV-2 Omicron variant-related cutaneous manifestations were described; moreover, skin derived cells were challenged in vitro with SARS-CoV-2 Omicron variant. Results The main clinical cutaneous features observed were urticarial lesions lasting more than 24 h, mainly involving the trunk and sometimes extending to the extremities, and miliaria presenting with clusters of small sweat-filled vesicles, sometimes surrounded by slight erythema. HaCaT keratinocytes, BJ fibroblast cell lines and outer root sheath (ORS) keratinocytes were not susceptible to SARS-CoV-2 Omicron variant infection; they also did not present any evident cytopathic effect or modification of cells viability. Conclusion Our findings suggests that, despite the high number of nucleotide mutations in the spike protein of SARS-CoV-2 Omicron variant, responsible to the higher transmissibility of this virus, and the increased reports of cutaneous manifestation in COVID-19 affected patients, the virus is not able to directly infect and damage the keratinocytes and fibroblasts, thus suggesting an indirect virus-induced activation of the immune system as the major pathogenetic driver.

Lowering Synaptogyrin‐3 Expression Rescues Tau‐Induced Memory Deficits and Synaptic Loss in the Presence of Microglial Activation

AbstractBackgroundTau is implicated in multiple neurodegenerative disorders, including Alzheimer’s disease. Synaptic loss and neuroinflammation are characteristic feautures of tauopathies, but it is unclear if these pathological events are causally linked and whether they are relevant for cognitive decline. Mutations and/or hyperphosphorylation of Tau leads its accumulation at synapses, where Tau binds to synaptic vesicle‐associated protein Synaptogyrin‐3 resulting in clustering of vesicles and impaired synaptic function. Given that Synaptogyrin‐3 is uniquely present at pre‐synaptic terminals, this allows us to decipher the contribution of pre‐synaptic Tau to overall Tau‐induced pathology.MethodWe generated a synaptogyrin‐3 knockout mouse line using CRISPR‐Cas9 technology. Synaptogyrin‐3−/− and +/− mice are viable and fertile and do not show overt phenotypes. We bred synaptogyrin‐3+/− mice with human Tau P301S‐expressing mice (PS19 line) and aged the offspring. We used several techniques, including electrophysiology, behavioral tests, immunohistochemistry and electron microscopy, to determine the effects of lowering Synaptogyrin‐3 expression in a tauopathy mouse model.ResultWe found that heterozygous knockout of Synaptogyrin‐3 in Tau P301S mice was sufficient to rescue synaptic plasticity and working memory defects. Moreover, lowering Synaptogyrin‐3 expression prevented synaptic degeneration and loss of synaptic markers in Tau P301S mice. Interestingly, proliferation and activation of astrocytes and microglia are observed in Tau P301S; synaptogyrin‐3+/− mice to the same extent as in their Tau P301S littermates.ConclusionOur results indicate that Tau induces synaptic loss and neuroinflammation independently, and that neuroinflammation is not sufficient to cause synaptic loss. In addition, pre‐synaptic defects caused by Tau are enough to drive defects in working memory.

Protein kinase R dependent phosphorylation of α-synuclein regulates its membrane binding and aggregation.

Aggregated α-synuclein (α-syn) accumulates in the neuronal Lewy body (LB) inclusions in Parkinson's disease (PD) and LB dementia. Yet, under nonpathological conditions, monomeric α-syn is hypothesized to exist in an equilibrium between disordered cytosolic- and partially α-helical lipid-bound states: a feature presumably important in synaptic vesicle release machinery. The exact underlying role of α-syn in these processes, and the mechanisms regulating membrane-binding of α-syn remains poorly understood. Herein we demonstrate that Protein kinase R (PKR) can phosphorylate α-syn at several Ser/Thr residues located in the membrane-binding region that is essential for α-syn's vesicle-interactions. α-Syn phosphorylated by PKR or α-syn isolated from PKR overexpressing cells, exhibit decreased binding to lipid membranes. Phosphorylation of Thr64 and Thr72 appears as the major contributor to this effect, as the phosphomimetic Thr64Glu/Thr72Glu-α-syn mutant displays reduced overall attachment to brain vesicles due to a decrease in vesicle-affinity of the last two thirds of α-syn's membrane binding region. This allows enhancement of the "double-anchor" vesicle-binding mechanism that tethers two vesicles and thus promote the clustering of presynaptic vesicles in vitro. Furthermore, phosphomimetic Thr64Glu/Thr72Glu-α-syn inhibits α-syn oligomerization and completely abolishes nucleation, elongation, and seeding of α-syn fibrillation in vitro and in cells, and prevents trans-synaptic spreading of aggregated α-syn pathology in organotypic hippocampal slice cultures. Overall, our findings demonstrate that normal and abnormal functions of α-syn, like membrane-binding, synaptic vesicle clustering and aggregation can be regulated by phosphorylation, e.g., via PKR. Mechanisms that could potentially be modulated for the benefit of patients suffering from α-syn aggregate-related diseases.

Expression and Subcellular Localization of Endocannabinoid System in Primary Interstitial Glandular Cells In Situ of Mice Ovary

Endocannabinoid synthesizing 2-AG and cannabinoid receptors have been reported in some organ of reproductive system and in oocyte of ovary, but little is known about the expression and subcellular localization of CB1 and DAGL-α in interstitial gland tissue of mouse ovary. The aim of this study was to explain the differential distribution of endocannabinoid system in interstitial glandular cell of mouse ovary. The CB1 and DAGL-α-immunoreactivities were detected within cells, which are consisted of smaller mitochondria with non-tubular cristae and fewer lipid droplets within the interstitial glands. Their immunoreactivities were localized in association with small vesicle clustering dispersed throughout the cytoplasm. The identity of the immunoreactive cells within interstitial glands were showed a possibility of co-existence of CB1 and DAGL-α in steroidogenic cells and autocrine or paracrine exertion of eCB signaling as well as involvement of eCB signaling in regulation of cell differentiation were discussed.
 HIGHLIGHTS
 
 2-arachidonoyl glycerol (2-AG, endocannabinoid)-synthesizing enzyme (DAGL-α) and its receptor CB1 localize to primary interstitial glandular cells of mice
 The first time of study for DAGL isozymes a co-localize with CB1 in interstitial glandular cells by Immuno-DAB-electron-microscopy. The new knowledge represents DAGL isozymes a and CB1 locate in the intracellular vesicles. This suggests that 2-AG by DAGL-α and CB1 receptor had co-existence its function through paracrine/autocrine released, as already known in oocyte, neurons and some other cells
 The distribution of DAGL isozymes a and CB1 in the interstitial gland tissues suggests that eCBs signaling molecules may be plays unique functions in steroidogenesis
 
 GRAPHICAL ABSTRACT

Condensation of the fusion focus by the intrinsically disordered region of the formin Fus1 is essential for cell-cell fusion

Secretory vesicle clusters transported on actin filaments by myosin V motors for local secretion underlie various cellular processes, such as neurotransmitter release at neuronal synapses,1 hyphal steering in filamentous fungi,2,3 and local cell wall digestion preceding the fusion of yeast gametes.4 During fission yeast Schizosaccharomyces pombe gamete fusion, the actin fusion focus assembled by the formin Fus1 concentrates secretory vesicles carrying cell wall digestive enzymes.5,6,7 The position and coalescence of the vesicle focus are controlled by local signaling and actin-binding proteins to prevent inappropriate cell wall digestion that would cause lysis,6,8,9,10 but the mechanisms of focusing have been elusive. Here, we show that the regulatory N terminus of Fus1 contains an intrinsically disordered region (IDR) that mediates Fus1 condensation invivo and forms dense assemblies that exclude ribosomes. Fus1 lacking its IDR fails to concentrate in a tight focus and causes cell lysis during attempted cell fusion. Remarkably, the replacement of Fus1 IDR with a heterologous low-complexity region that forms molecular condensates fully restores Fus1 focusing and function. By contrast, the replacement of Fus1 IDR with a domain that forms more stable oligomers restores focusing but poorly supports cell fusion, suggesting that condensation is tuned to yield a selectively permeable structure. We propose that condensation of actin structures by an IDR may be a general mechanism for actin network organization and the selective local concentration of secretory vesicles.

Herpes Zoster Ophthalmicus and Encephalitis Following Botulinum Toxin Type A Injection for Blepharospasm: A Case Report

A 68- year – old male was admitted to ER of Referral Imam Khomeini hospital with abrupt commence of fever accompanied with debilitating non-radiating headache, photophobia, ataxia and cluster of confluent vesicles on right side of forehead with swelling of right eyelid. All his symptoms started after receiving Botulinum injection on the same week before admission and he had never had similar manifestations beforehand.
 His medical history was remarkable for hyperlipidemia, hypertension and right side Blepharospasm for which he received Botulinum injection every 6 months. He was on medication for the rest of his medical problems. He was not on any immunosuppressive medication and did not suffer from any disease weakening the immune system. His family history was unremarkable for any similar problems.
 In medical exam, he was ill but not toxic, his vital signs were blood pressure of 135/80 mmHg, heart rate of 76, respiratory rate of 17 and oral temperature of 38.5Ĉ. He had vesicles on his right forehead. Heart sounds were regular without murmur. Lungs were clear. Abdominal examinations were inconspicuous.
 In neurological examinations, he was confused and disoriented to time and place. Cranial nerves were without any pathological findings except for positive Marcus Gunn of affected side and blurring of right optic disk margin. No muscle atrophy was seen. Muscle force showed no weakness. He was ataxic. Sensory examination was normal. Reflexes were checked and were within normal limits and symmetric.
 Computer tomography (CT) scan of head was unremarkable and his MRI scan did not reveal any information compatible with his symptoms.
 Due to the sudden onset of fever with headache and confusion, encephalitis was suspected and empirical therapy with antibiotics was started and LP was performed which indicated pleocytosis in CSF. According to the vesicles on the skin and with suspicion of Varicella encephalitis, PCR was sent for diagnosis of VZV. Subsequently, his condition got dramatically better and symptoms diminished after acyclovir was started.

Axonal α7* nicotinic acetylcholine receptors modulate glutamatergic signaling and synaptic vesicle organization in ventral hippocampal projections.

Modulation of the release of glutamate by activation of presynaptic nicotinic acetylcholine receptors (nAChRs) is one of the most prevalent mechanism of nicotinic facilitation of glutamatergic transmission in cortico-limbic circuits. By imaging gene chimeric co-cultures from mouse, we examined the role of α7* nAChRs mediated cholinergic modulation of glutamate release and synaptic vesicle organization in ventral hippocampal projections. We directly visualized exogenous and endogenous cholinergic facilitation of glutamate release in this specialized preparation of circuits in vitro. Disrupting α7* nAChRs mediated cholinergic signaling genetically or pharmacologically diminished cholinergic facilitation of glutamate release at presynaptic terminals. Alteration of α7* nAChRs mediated cholinergic signaling along glutamatergic axons also decreased functional synaptic vesicle clustering to presynaptic terminals. These findings suggest that presynaptic α7* nAChRs contribute to cholinergic modulation of glutamate release and synaptic vesicle organization.

The Synergistic Effect of Thiamethoxam and Synapsin dsRNA Targets Neurotransmission to Induce Mortality in Aphis gossypii.

Sublethal doses of insecticides have many impacts on pest control and agroecosystems. Insects that survive a sublethal dose of insecticide could adapt their physiological and behavioral functions and resist this environmental stress, which contributes to the challenge of pest management. In this study, the sublethal effects of thiamethoxam on gene expression were measured through RNA sequencing in the melon aphid Aphis gossypii. Genes regulating energy production were downregulated, while genes related to neural function were upregulated. To further address the function of genes related to neurotransmission, RNA interference (RNAi) was implemented by transdermal delivery of dsRNA targeting synapsin (syn), a gene regulating presynaptic vesicle clustering. The gene expression of synapsin was knocked down and the mortality of aphids was increased significantly over the duration of the assay. Co-delivery of syn-dsRNA and thiamethoxam reversed the upregulation of synapsin caused by low-dose thiamethoxam and resulted in lethality to melon aphids, suggesting that the decreased presynaptic function may contribute to this synergistic lethal effect. In addition, the nanocarrier star polycation, which could bind both dsRNA and thiamethoxam, greatly improved the efficacy of lethality. These results increase our knowledge of the gene regulation induced by sublethal exposure to neonicotinoids and indicated that synapsin could be a potential RNAi target for resistance management of the melon aphid.

Ophthalmic manifestation of monkeypox infection

A 39-year-old, White, bisexual male attended our sexual health clinic with proctitis and a cluster of vesicles (2–3 mm) in the anal region, which had presented 3 days previously. He declared having had multiple unprotected sexual encounters and being on pre-exposure prophylaxis for HIV prevention since 2019. Over the previous 3 weeks, he had travelled to France and Germany, before returning to Italy.

Extracellular Vesicles for Immunomodulation in Tissue Regeneration.

A large number of people suffer from tissue injury and defect worldwide, which constitutes a critical challenge for regenerative medicine. During the complicated process of tissue repair and regeneration, immune response that involves many kinds of immune cells often concurrently exists and plays a significant role, thus providing a promising target for the development of therapeutic strategies. As a critical player in cell-cell communication, extracellular vesicles (EVs) are a cluster of nano-sized vesicles of different categories, which have been reported to possess favorable immunoregulatory potential, and participate in the process of tissue repair and regeneration. Furthermore, EVs can be engineered with genetic or chemical strategies for optimized performance as therapeutic mediators. Here, we provide an outline on the biology of EVs as well as the role of EVs in immune regulation, focusing on exosomes, microvesicles, and apoptotic vesicles. We further summarize the applications of EV-based therapies for tissue regeneration, with particular emphasis on the modulation of immune system. Also, we have discussed the construction strategies of engineered EVs and the immunomodulatory capability of engineered EVs as well as their therapeutic potential in tissue repair. This review will highlight the outstanding potential of EV-based therapeutic strategies for tissue repair and regeneration. Impact statement Extracellular vesicles (EVs) have been shown to possess potent immunomodulatory abilities and thus hold great therapeutic potential for regenerative medicine via immune modulation. Also, the development of engineering technology has provided a feasible tool for optimizing the performance of natural EVs. We hereby outline the current knowledge regarding the features of EVs and the construction strategies of engineered EVs as well as the immunomodulation effects of natural and engineered EVs. We also highlight the applications of EV-based therapies for tissue regeneration, with particular emphasis on the modulation of immune system.

An anti-picornaviral strategy based on the crystal structure of foot-and-mouth disease virus 2C protein.

The foot-and-mouth disease virus (FMDV) 2C protein shares conserved motifs with enterovirus 2Cs despite low sequence identity. Here, we determine the crystal structure of an FMDV 2C fragment to 1.83Å resolution, which comprises an ATPase domain, a region equivalent to the enterovirus 2C zinc-finger (ZFER), and a C-terminal domain harboring a loop (PBL) that occupies a hydrophobic cleft (Pocket) in an adjacent 2C molecule. Mutations at ZFER, PBL, and Pocket affect FMDV 2C ATPase activity and are lethal to FMDV infectious clones. Because the PBL-Pocket interaction between FMDV 2C molecules is essential for its functions, we design an anti-FMDV peptide derived from PBL (PBL-peptide). PBL-peptide inhibits FMDV 2C ATPase activity, binds FMDV 2C with nanomolar affinity, and disrupts FMDV 2C oligomerization. FMDV 2C targets lipid droplets (LDs) and induces LD clustering in cells, and PBL-peptide disrupts FMDV 2C-induced LD clustering. Finally, we demonstrate that PBL-peptide exhibits anti-FMDV activity in cells.

Plasticity of Membrane Binding by the Central Region of α-Synuclein.

Membrane binding by α-synuclein (αS), an intrinsically disordered protein whose aggregation is associated with Parkinson’s disease, is a key step in determining its biological properties under both physiological and pathological conditions. Upon membrane interaction, αS retains a partial level of structural disorder despite acquiring α-helical content. In the membrane-bound state, the equilibrium between the helical-bound and disordered-detached states of the central region of αS (residues 65–97) has been involved in a double-anchor mechanism that promotes the clustering of synaptic vesicles. Herein, we investigated the underlying molecular bases of this equilibrium using enhanced coarse-grained molecular dynamics simulations. The results enabled clarifying the conformational dependencies of the membrane affinity by this protein region that, in addition to playing a role in physiological membrane binding, has key relevance for the aggregation of αS and the mechanisms of the toxicity of the resulting assemblies.

Effect of <i>Ginkgo biloba</i> extract on Histomorphometric changes of Hippocampus against Fluoride Toxicity in Wistar Rats

Prolonged ingestion of fluoride leads to the pathogenesis known as fluorosis. Fluoride exposure leads to neuro degenerative changes such as reduction in the neuronal cell size and number. Exposure to fluoride showed neurodegenerative changes like shrunken neurons, increased in folding of the nuclear membrane, mitochondrial alterations, and dilated rough endoplasmic reticulum cisternae and clusters of vesicles near the Golgi bodies. Present study is to explore the histomorphometric changes of the hippocampus of fluoride induced brain and treated with Ginkgo biloba Extract (GBE). Thirty number (30) adult male Wistar rats were randomly separated into 5 Groups (n=6). Group1 (Control) supplemented with water, 2 to 5 Groups were supplemented with 100ppm of sodium fluoride for 30 days, while the Groups 3, 4, and 5 were Ginkgo biloba extract treated at 50mg/ kg, 100mg/kg and 200mg/kg body weight for 15 days, after sodium fluoride treatment, results showed that, 200mg/kg GBE provided effective and complete protection against fluoride toxicity. From the present study concluded that 50, 100 and 200 mg/kg GBE was significantly attenuated the fluoride induced toxicity in a dose depending manner. Present histomorphometrical study showed delayed neuronal death in the CA1 and CA3 regions of hippocampus of fluoride group that was significantly attenuated by GBE (50,100 and 200 mg/kg) in a dose dependant manner.

SHIP164 is a chorein motif lipid transfer protein that controls endosome-Golgi membrane traffic.

Cellular membranes differ in protein and lipid composition as well as in the protein-lipid ratio. Thus, progression of membranous organelles along traffic routes requires mechanisms to control bilayer lipid chemistry and their abundance relative to proteins. The recent structural and functional characterization of VPS13-family proteins has suggested a mechanism through which lipids can be transferred in bulk from one membrane to another at membrane contact sites, and thus independently of vesicular traffic. Here, we show that SHIP164 (UHRF1BP1L) shares structural and lipid transfer properties with these proteins and is localized on a subpopulation of vesicle clusters in the early endocytic pathway whose membrane cargo includes the cation-independent mannose-6-phosphate receptor (MPR). Loss of SHIP164 disrupts retrograde traffic of these organelles to the Golgi complex. Our findings raise the possibility that bulk transfer of lipids to endocytic membranes may play a role in their traffic.

ATG9 Vesicles Are Incorporated Into Nascent Autophagosome Membranes

The autophagosome is a double‐membrane organelle that traps cytoplasmic cargo and traffics it to the lysosome for degradation. How the autophagosome forms is uncertain, but a prevailing model suggests lipids are moved from the ER through the lipid transporter ATG2 to ATG9 vesicles, which then expand to comprise the growing autophagosomal membrane. However, evidence that ATG9 is ever resident within the autophagosome is scant; detection of this putative autophagosome‐resident protein is made challenging both because most ATG9 vesicles in the cell are not involved in the biogenesis at any given time and because the dilution of one or a few vesicle membranes by potentially millions of transported lipids would result in a very low density of ATG9 on the mature autophagosome. Here we develop approaches to address each of these limitations. First, we show that in genetic knockouts of ATG2, ATG9 vesicles accumulate to very high numbers at sites of aborted autophagosome formation. Focused‐ion beam scanning electron microscopy reveals that without ATG2, these putative autophagosome seed vesicles do not expand, but instead accumulate within a large vesicle cluster surrounded by ER. By fluorescence microscopy, we also detect downstream modifiers of the autophagosome membrane at these sites, including the lipid‐anchored form of the LC3 proteins, which suggests that a biochemically competent seed membrane is present. To establish whether ATG9A is found on the same membrane as LC3B, we use styrene maleic acid (SMA) copolymer nanodiscs, to isolate very small intact sections of autophagosome membrane away from all other potential contaminants. Through rigorous combinations of isolation and purification, we reveal that ATG9A and LC3B are co‐resident within the same 10 nm diameter membrane segment and likely engage in a protein‐protein complex. We then apply the same SMA‐based approach to show that even in wildtype autophagosomes, ATG9 and LC3 are co‐resident. Thus, we assert that ATG9 vesicles are the seed membrane for the autophagosome.

Hemisynapse Formation Between Target Astrocytes and Cortical Neuron Axons in vitro.

One of the most fundamental organizing principles in the mammalian brain is that neurons do not establish synapses with the other major cell type, the astrocytes. However, induced synapse formation between neurons and astrocytes appears conceivable, because astrocytes are well known to express functional ionotropic glutamate receptors. Here, we attempted to trigger synapse formation between co-cultured neurons and astrocytes by overexpressing the strongly synaptogenic adhesion protein LRRTM2 in astrocytes physically contacted by cortical axons. Interestingly, control experiments with immature cortical astrocytes without any overexpression resulted in the induction of synaptic vesicle clustering in contacting axons (hemisynapse formation). This synaptogenic activity correlated with the endogenous expression of the synaptogenic protein Neuroligin1. Hemisynapse formation was further enhanced upon overexpression of LRRTM2 in cortical astrocytes. In contrast, cerebellar astrocytes required overexpression of LRRTM2 for induction of synaptic vesicle clustering in contacting axons. We further addressed, whether hemisynapse formation was accompanied by the appearance of fully functional glutamatergic synapses. We therefore attempted to record AMPA receptor-mediated miniature excitatory postsynaptic currents (mEPSCs) in innervated astrocytes using the whole-cell patch-clamp technique. Despite the endogenous expression of the AMPA receptor subunits GluA2 and to a lesser extent GluA1, we did not reliably observe spontaneous AMPA mEPSCs. In conclusion, overexpression of the synaptogenic protein LRRTM2 induced hemisynapse formation between co-cultured neurons and astrocytes. However, the formation of fully functional synapses appeared to require additional factors critical for nano-alignment of presynaptic vesicles and postsynaptic receptors.

Ultrastructure of spermatozoa of a hairworm Gordionus alpestris (Villot, 1885) (Nematomorpha, Chordodidae)

ABSTRACT Sperm ultrastructure of the hairworm Gordionus alpestris (Nematomorpha, Chordodidae) has been studied. Spermatozoa are elongated aflagellate cells of clavate shape. Their dilated anterior part consists of an acrosomal complex comprising an apical acrosomal vesicle and axial acrosomal tube enveloped by an acrosomal sheath of four membrane-bound compartments. The basal part of the tube contains a cluster of vesicles. The slender posterior part of the spermatozoa includes an axial nucleus without a nuclear envelope surrounded by a halo and multivesicular complex composed of cisternae arranged into three layers. Spermatozoa of G. alpestris are nearly identical in size, proportion and internal structure to those of other gordiid spermatozoa. This uniformity makes spermatozoa useless for taxon descriptions and differentiation of Gordiida. The basic pattern of spermatozoon structure in Gordiida is not fully understood and requires more detailed studies. Controversies include absence or presence of the nuclear envelope and mitochondria, together with interpretation of the halo surrounding nuclei and membranous compartments of the acrosomal and multivesicular complexes. Detailed study of sperm development together with cytochemical analysis of components such as mitochondria, acrosome, perforatorium and halo might be helpful for understanding sperm relationships of Gordiida and Nematoda.

Cold atmospheric plasma inhibits vesicle transport of human osteosarcoma cells visualized by super‐resolution fluorescence microscopy

AbstractVesicle transport plays a key role in cancer invasion and metastasis. As a promising cancer treatment modality, the impact of cold atmospheric plasma (CAP) on vesicle transport has been barely examined. In this study, super‐resolution structured illumination microscopy (SIM) was employed to track the intracellular vesicles of osteosarcoma cells. Results indicated that CAP exposure could disintegrate vesicle clusters and individual vesicles. After 20 s of CAP treatment, the average velocity of intracellular vesicles decreased from 0.140 to 0.037 μm/s, while the 60 s maximum displacement declined from 7.76 to 3.26 μm. Significant inhibition of vesicle transport between osteosarcoma cells and human bronchial epithelium was observed after CAP treatment. These findings may shed some light on understanding CAP–cancer cell interactions.