scholarly journals ATG5 is instrumental in the transition from autophagy to apoptosis during the degeneration of tick salivary glands

2021 ◽  
Vol 15 (1) ◽  
pp. e0009074
Author(s):  
Yanan Wang ◽  
Houshuang Zhang ◽  
Li Luo ◽  
Yongzhi Zhou ◽  
Jie Cao ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Calcium Concentration ◽  
High Concentration ◽  
Normal Feeding ◽  
Feeding Process ◽  
High Concentrations ◽  
Caspase Gene ◽  
Tick Salivary Glands

Female tick salivary glands undergo rapid degeneration several days post engorgement. This degeneration may be caused by the increased concentration of ecdysone in the hemolymph during the fast feeding period and both autophagy and apoptosis occur. In this work, we first proved autophagy-related gene (ATG) and caspase gene expression peaks during degeneration of the tick salivary glands. We explored the regulatory role of Rhipicephalus haemaphysaloides autophagy-related 5 (RhATG5) in the degeneration of tick salivary glands. During the fast feeding phase, RhATG5 was cleaved and both calcium concentration and the transcription of Rhcalpains increased in the salivary glands. Recombinant RhATG5 was cleaved by μ-calpain only in the presence of calcium; the mutant RhATG5191-199Δ was not cleaved. Treatment with 20-hydroxyecdysone (20E) led to programmed cell death in the salivary glands of unfed ticks in vitro, RhATG8-phosphatidylethanolamine (PE) was upregulated in ticks treated with low concentration of 20E. Conversely, RhATG8-PE decreased and Rhcaspase-7 increased in ticks treated with a high concentration of 20E and transformed autophagy to apoptosis. High concentrations of 20E led to the cleavage of RhATG5. Calcium concentration and expression of Rhcalpains were also upregulated in the tick salivary glands. RNA interference (RNAi) of RhATG5 in vitro inhibited both autophagy and apoptosis of the tick salivary glands. RNAi of RhATG5 in vivo significantly inhibited the normal feeding process. These results demonstrated that high concentrations of 20E led to the cleavage of RhATG5 by increasing the concentration of calcium and stimulated the transition from autophagy to apoptosis.

scholarly journals ATG5 is instrumental in the transition from autophagy to apoptosis during the degeneration of tick salivary glands

2020 ◽  
Author(s):  
Yanan Wang ◽  
Houshuang Zhang ◽  
Li Luo ◽  
Yongzhi Zhou ◽  
Jie Cao ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Calcium Concentration ◽  
High Concentration ◽  
Normal Feeding ◽  
Feeding Process ◽  
High Concentrations ◽  
Caspase Gene ◽  
Tick Salivary Glands

AbstractFemale tick salivary glands undergo rapid degeneration several days post engorgement. This degeneration may be caused by the increased concentration of ecdysone in the hemolymph during the fast feeding period and both autophagy and apoptosis occur. In this work, we first proved ATG and Caspase gene expression peaks during degeneration of the tick salivary glands. We explored the regulatory role of Rhipicephalus haemaphysaloides autophagy related 5 (RhATG5) in the degeneration of tick salivary glands. During the fast feeding phase, RhATG5 was cleaved and both calcium concentration and the transcription of RhCalpains increased in the salivary glands. Recombinant RhATG5 was cleaved by μ-Calpain only in the presence of calcium; the mutant RhATG5191-199Δ was not cleaved. Treatment with 20-hydroxyecdysone (20E) led to programmed cell death in the salivary glands of unfed ticks in vitro, RhATG8-phosphatidylethanolamine (PE) was upregulated in ticks treated with low concentration of 20E. Conversely, RhATG8-PE decreased and RhCaspase-7 increased in ticks treated with a high concentration of 20E and transformed autophagy to apoptosis. High concentrations of 20E led to the cleavage of RhATG5. Calcium concentration and expression of RhCalpains were also upregulated in the tick salivary glands. RNA interference (RNAi) of RhATG5 in vitro inhibited both autophagy and apoptosis of the tick salivary glands. RNAi of RhATG5 in vivo significantly inhibited the normal feeding process. These results demonstrated that high concentrations of 20E led to the cleavage of RhATG5 by increasing the concentration of calcium and stimulated the transition from autophagy to apoptosis.

scholarly journals The Swallowing Characteristics of Thickeners, Jellies and Yoghurt Observed Using an In Vitro Model

Dysphagia ◽  
2019 ◽  
Vol 35 (4) ◽  
pp. 685-695 ◽  
Author(s):  
Simmi Patel ◽  
William J. McAuley ◽  
Michael T. Cook ◽  
Yi Sun ◽  
Shaheen Hamdy ◽  
...  
Keyword(s):  
Transit Time ◽  
Mechanical Model ◽  
Xanthan Gum ◽  
In Vitro Model ◽  
High Concentration ◽  
High Concentrations ◽  
Vitro Model ◽  
Thickening Agents

Abstract Drinks and foods may be thickened to improve swallowing safety for dysphagia patients, but the resultant consistencies are not always palatable. Characterising alternative appetising foods is an important task. The study aims to characterise the in vitro swallowing behaviour of specifically formulated thickened dysphagia fluids containing xanthan gum and/or starch with standard jellies and yoghurt using a validated mechanical model, the “Cambridge Throat”. Observing from the side, the model throat can follow an experimental oral transit time (in vitro-OTT) and a bolus length (BL) at the juncture of the pharynx and larynx, to assess the velocity and cohesion of bolus flow. Our results showed that higher thickener concentration produced longer in vitro-OTT and shorter BL. At high concentration (spoon-thick), fluids thickened with starch-based thickener showed significantly longer in vitro-OTT than when xanthan gum-based thickener was used (84.5 s ± 34.5 s and 5.5 s ± 1.6 s, respectively, p < 0.05). In contrast, at low concentration (nectar-like), fluids containing xanthan gum-based thickener demonstrated shorter BL than those of starch-based thickener (6.4 mm ± 0.5 mm and 8.2 mm ± 0.8 mm, respectively, p < 0.05). The jellies and yoghurt had comparable in vitro-OTT and BL to thickeners at high concentrations (honey-like and spoon-thick), indicating similar swallowing characteristics. The in vitro results showed correlation with published in vivo data though the limitations of applying the in vitro swallowing test for dysphagia studies were noted. These findings contribute useful information for designing new thickening agents and selecting alternative and palatable safe-to-swallow foods.

Immunological investigations of oligoethylene glycols functionalized with desaminotyrosine and desaminotyrosyltyrosine

2013 ◽  
Vol 1569 ◽  
pp. 9-14 ◽  
Author(s):  
Konstanze K. Julich-Gruner ◽  
Toralf Roch ◽  
Nan Ma ◽  
Axel T. Neffe ◽  
Andreas Lendlein
Keyword(s):  
Human Blood ◽  
High Concentration ◽  
Inflammatory Conditions ◽  
Tnf Α ◽  
High Concentrations ◽  
Pharmaceutical Agents ◽  
Immunological Evaluation ◽  
Necrosis Factor

ABSTRACTBiomaterials require thorough in vitro testing before being applied in vivo. Unwanted contaminations of biomaterials but also their intrinsic properties can cause uncontrolled immune response leading to severe consequences for the patient. Therefore, immunological evaluation of materials for biomedical applications is mandatory before entering clinical application. In order to introduce physical netpoints, the aromatic compounds desaminotyrosine (DAT) and desaminotyrosyl-tyrosine (DATT) were successfully used to functionalize linear and star-shaped oligoethylene glycol (lOEG and sOEG) as previously described. The materials showed properties of surfactants and have potential to be used for solubilization of lipophilic drugs in water. Furthermore, the materials are susceptible for H2O2 degradation as determined by MALDI-ToF MS analyses. This is important for potential in vivo applications, as macrophages can release reactive oxygen species (ROS) under inflammatory conditions. As it is known that surfactant solutions of high concentration can lead to cell lysis, the effects of OEG-DAT(T) solutions on murine RAW macrophages were investigated. Even at highest OEG-DAT(T) concentration of 1000 µg·mL-1 the viability of the RAW cells was not significantly impaired. Additionally, the polymers were incubated with whole human blood and the production of inflammatory cytokines such as the tumor necrosis factor (TNF)-α and interleukin (IL)-6 was determined. Only at high concentrations, the OEG-DAT(T) solution induced low levels of TNF-α and IL-6, indicating that a mild inflammatory reaction could be expected when such high OEG-DAT(T) concentrations are applied in vivo. Similarly, the OEG-DAT(T) solution did not induce ROS in monocytes and neutrophils after incubation with whole human blood. Conclusively, the data presented here demonstrate that OEG-DAT(T) do not lead to a substantial activation of the innate immune mechanisms and could therefore be investigated for solubilizing pharmaceutical agents.

Rapid freezing of the mouse blastocyst: effects of cryoprotectants and of time and temperature of exposure to cryoprotectant before direct plunging into liquid nitrogen

1991 ◽  
Vol 3 (2) ◽  
pp. 175 ◽  
Author(s):  
R Li ◽  
A Trounson
Keyword(s):  
Liquid Nitrogen ◽  
Room Temperature ◽  
Rapid Freezing ◽  
High Concentration ◽  
Freezing And Thawing ◽  
Initial Exposure ◽  
Survival And Development ◽  
High Concentrations

This study investigates the effects of time and temperature of exposure to a high concentration (4.5 M) of dimethyl sulfoxide (DMSO), glycerol, 1,2-propanediol (PROH), or a mixture of DMSO and glycerol (DG) in a solution containing 0.25 M sucrose, on the survival and development of rapidly frozen mouse blastocysts. Embryos had significantly (P less than 0.01) higher rates of survival and development when exposed to cryoprotectant at 0 degree C compared with room temperature. The time of exposure to cryoprotectant at either 0 degree C or room temperature before being plunged into liquid nitrogen significantly (P less than 0.01) affected the survival and development of frozen-thawed embryos. Survival and development of blastocysts in vitro and in vivo was significantly (P less than 0.05) higher when exposed at 0 degree C for 10 min to DG, DMSO and glycerol than to PROH. It is concluded that, unlike early-cleavage stage embryos, blastocysts need to be equilibrated at a low temperature (0 degree C) with high concentrations of cryoprotectant before rapid freezing. Exposure of blastocysts to 4.5 M cryoprotectant and 0.25 M sucrose at room temperature either was toxic or else markedly reduced their viability after freezing and thawing, depending on the duration of the initial exposure.

scholarly journals High-Dose Benzodiazepines Positively Modulate GABAA Receptors via a Flumazenil-Insensitive Mechanism

2021 ◽  
Vol 23 (1) ◽  
pp. 42
Author(s):  
Na Wang ◽  
Jingjing Lian ◽  
Yanqing Cao ◽  
Alai Muheyati ◽  
Shanshan Yuan ◽  
...  
Keyword(s):  
Gabaa Receptors ◽  
High Dose ◽  
High Concentration ◽  
Concentration Effects ◽  
In Vivo Evaluation ◽  
Chemical Structures ◽  
Loss Of Righting Reflex ◽  
High Concentrations

Benzodiazepines (BZDs) produce versatile pharmacological actions through positive modulation of GABAA receptors (GABAARs). A previous study has demonstrated that high concentrations of diazepam potentiate GABA currents on the α1β2γ2 and α1β2 GABAARs in a flumazenil-insensitive manner. In this study, the high-concentration effects of BZDs and their sensitivity to flumazenil were determined on synaptic (α1β2γ2, α2β2γ2, α5β2γ2) and extra-synaptic (α4β2δ) GABAARs using the voltage-clamp electrophysiology technique. The in vivo evaluation of flumazenil-insensitive BZD effects was conducted in mice via the loss of righting reflex (LORR) test. Diazepam induced biphasic potentiation on the α1β2γ2, α2β2γ2 and α5β2γ2 GABAARs, but did not affect the α4β2δ receptor. In contrast to the nanomolar component of potentiation, the second potentiation elicited by micromolar diazepam was insensitive to flumazenil. Midazolam, clonazepam, and lorazepam at 200 µM exhibited similar flumazenil-insensitive effects on the α1β2γ2, α2β2γ2 and α5β2γ2 receptors, whereas the potentiation induced by 200 µM zolpidem or triazolam was abolished by flumazenil. Both the GABAAR antagonist pentylenetetrazol and Fa173, a proposed transmembrane site antagonist, abolished the potentiation induced by 200 µM diazepam. Consistent with the in vitro results, flumazenil antagonized the zolpidem-induced LORR, but not that induced by diazepam or midazolam. Pentylenetetrazol and Fa173 antagonized the diazepam-induced LORR. These findings support the existence of non-classical BZD binding sites on certain GABAAR subtypes and indicate that the flumazenil-insensitive effects depend on the chemical structures of BZD ligands.

The Effects of Shock Vancomycin Concentrations on the Formation of Heteroresistance in Staphylococcus aureus

2020 ◽  
Vol 65 (9-10) ◽  
pp. 3-7
Author(s):  
V. V. Gostev ◽  
Yu. V. Sopova ◽  
O. S. Kalinogorskaya ◽  
M. E. Velizhanina ◽  
I. V. Lazareva ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
In Vitro Selection ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
High Concentration ◽  
Short Term ◽  
High Concentrations ◽  
Selection Of ◽  
Selection Of Resistance ◽  
Test Cultures

Glycopeptides are the basis of the treatment of infections caused by MRSA (Methicillin-Resistant Staphylococcus aureus). Previously, it was demonstrated that antibiotic tolerant phenotypes are formed during selection of resistance under the influence of high concentrations of antibiotics. The present study uses a similar in vitro selection model with vancomycin. Clinical isolates of MRSA belonging to genetic lines ST8 and ST239, as well as the MSSA (ATCC29213) strain, were included in the experiment. Test isolates were incubated for five hours in a medium with a high concentration of vancomycin (50 μg/ml). Test cultures were grown on the medium without antibiotic for 18 hours after each exposure. A total of ten exposure cycles were performed. Vancomycin was characterized by bacteriostatic action; the proportion of surviving cells after exposure was 70–100%. After selection, there was a slight increase in the MIC to vancomycin (MIC 2 μg/ml), teicoplanin (MIC 1.5–3 μg/ml) and daptomycin (MIC 0.25–2 μg/ml). According to the results of PAP analysis, all strains showed an increase in the area under curve depending on the concentration of vancomycin after selection, while a heteroresistant phenotype (with PAP/AUC 0.9) was detected in three isolates. All isolates showed walK mutations (T188S, D235N, E261V, V380I, and G223D). Exposure to short-term shock concentrations of vancomycin promotes the formation of heteroresistance in both MRSA and MSSA. Formation of VISA phenotypes is possible during therapy with vancomycin.

scholarly journals Enterococcus faecalis exploits the human fibrinolytic system to drive excess collagenolysis: implications in gut healing and identification of druggable targets

2020 ◽  
Vol 318 (1) ◽  
pp. G1-G9 ◽  
Author(s):  
Richard A. Jacobson ◽  
Kiedo Wienholts ◽  
Ashley J. Williamson ◽  
Sara Gaines ◽  
Sanjiv Hyoju ◽  
...  
Keyword(s):  
Enterococcus Faecalis ◽  
Healing Process ◽  
Abdominal Sepsis ◽  
Infectious Complications ◽  
Fibrinolytic System ◽  
Clinical Safety ◽  
High Concentrations ◽  
Clinically Significant

Perforations, anastomotic leak, and subsequent intra-abdominal sepsis are among the most common and feared complications of invasive interventions in the colon and remaining intestinal tract. During physiological healing, tissue protease activity is finely orchestrated to maintain the strength and integrity of the submucosa collagen layer in the wound. We (Shogan, BD et al. Sci Trans Med 7: 286ra68, 2015.) have previously demonstrated in both mice and humans that the commensal microbe Enterococcus faecalis selectively colonizes wounded colonic tissues and disrupts the healing process by amplifying collagenolytic matrix-metalloprotease activity toward excessive degradation. Here, we demonstrate for the first time, to our knowledge, a novel collagenolytic virulence mechanism by which E. faecalis is able to bind and locally activate the human fibrinolytic protease plasminogen (PLG), a protein present in high concentrations in healing colonic tissue. E. faecalis-mediated PLG activation leads to supraphysiological collagen degradation; in this study, we demonstrate this concept both in vitro and in vivo. This pathoadaptive response can be mitigated with the PLG inhibitor tranexamic acid (TXA) in a fashion that prevents clinically significant complications in validated murine models of both E. faecalis- and Pseudomonas aeruginosa-mediated colonic perforation. TXA has a proven clinical safety record and is Food and Drug Administration approved for topical application in invasive procedures, albeit for the prevention of bleeding rather than infection. As such, the novel pharmacological effect described in this study may be translatable to clinical trials for the prevention of infectious complications in colonic healing. NEW & NOTEWORTHY This paper presents a novel mechanism for virulence in a commensal gut microbe that exploits the human fibrinolytic system and its principle protease, plasminogen. This mechanism is targetable by safe and effective nonantibiotic small molecules for the prevention of infectious complications in the healing gut.

scholarly journals Collagen-Based Electrospun Materials for Tissue Engineering: A Systematic Review

2021 ◽  
Vol 8 (3) ◽  
pp. 39
Author(s):  
Britani N. Blackstone ◽  
Summer C. Gallentine ◽  
Heather M. Powell
Keyword(s):  
Systematic Review ◽  
Tissue Engineering ◽  
Collagen Type I ◽  
The Body ◽  
Pool Data ◽  
Type I ◽  
High Concentrations ◽  
Increased Strength

Collagen is a key component of the extracellular matrix (ECM) in organs and tissues throughout the body and is used for many tissue engineering applications. Electrospinning of collagen can produce scaffolds in a wide variety of shapes, fiber diameters and porosities to match that of the native ECM. This systematic review aims to pool data from available manuscripts on electrospun collagen and tissue engineering to provide insight into the connection between source material, solvent, crosslinking method and functional outcomes. D-banding was most often observed in electrospun collagen formed using collagen type I isolated from calfskin, often isolated within the laboratory, with short solution solubilization times. All physical and chemical methods of crosslinking utilized imparted resistance to degradation and increased strength. Cytotoxicity was observed at high concentrations of crosslinking agents and when abbreviated rinsing protocols were utilized. Collagen and collagen-based scaffolds were capable of forming engineered tissues in vitro and in vivo with high similarity to the native structures.

scholarly journals Compensatory mechanisms in resistant Anopheles gambiae AcerKis and KdrKis neurons modulate insecticide-based mosquito control

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Stéphane Perrier ◽  
Eléonore Moreau ◽  
Caroline Deshayes ◽  
Marine El-Adouzi ◽  
Delphine Goven ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Anopheles Gambiae ◽  
Calcium Concentration ◽  
Mosquito Control ◽  
Point Mutations ◽  
Resting Membrane Potential ◽  
Compensatory Mechanisms ◽  
Pyrethroid Insecticides

AbstractIn the malaria vector Anopheles gambiae, two point mutations in the acetylcholinesterase (ace-1R) and the sodium channel (kdrR) genes confer resistance to organophosphate/carbamate and pyrethroid insecticides, respectively. The mechanisms of compensation that recover the functional alterations associated with these mutations and their role in the modulation of insecticide efficacy are unknown. Using multidisciplinary approaches adapted to neurons isolated from resistant Anopheles gambiae AcerKis and KdrKis strains together with larval bioassays, we demonstrate that nAChRs, and the intracellular calcium concentration represent the key components of an adaptation strategy ensuring neuronal functions maintenance. In AcerKis neurons, the increased effect of acetylcholine related to the reduced acetylcholinesterase activity is compensated by expressing higher density of nAChRs permeable to calcium. In KdrKis neurons, changes in the biophysical properties of the L1014F mutant sodium channel, leading to enhance overlap between activation and inactivation relationships, diminish the resting membrane potential and reduce the fraction of calcium channels available involved in acetylcholine release. Together with the lower intracellular basal calcium concentration observed, these factors increase nAChRs sensitivity to maintain the effect of low concentration of acetylcholine. These results explain the opposite effects of the insecticide clothianidin observed in AcerKis and KdrKis neurons in vitro and in vivo.

scholarly journals Replacement of Albumin by Preovulatory Oviductal Fluid in Swim-Up Sperm Preparation Method Modifies Boar Sperm Parameters and Improves In Vitro Penetration of Oocytes

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1202
Author(s):  
Sergio Navarro-Serna ◽  
Evelyne París-Oller ◽  
Ondrej Simonik ◽  
Raquel Romar ◽  
Joaquín Gadea
Keyword(s):  
Calcium Concentration ◽  
Preparation Method ◽  
Culture Media ◽  
Penetration Rate ◽  
Sperm Parameters ◽  
High Concentration ◽  
Sperm Preparation ◽  
Boar Sperm ◽  
Oviductal Fluid

More suitable and efficient methods to protect gametes from external harmful effects during in vitro handling can be achieved by adding preovulatory porcine oviductal fluid (pOF) to in vitro culture media. The objective of this study was to assess the swim-up procedure’s suitability as a sperm selection method using a medium supplemented with 1mg/mL BSA, 1% preovulatory pOF (v/v), 1% v/v pOF plus 1mg/mL BSA, and 5mg/mL BSA. After selection, various sperm parameters were studied, such as sperm recovery rate, sperm morphology, motility (by CASA), vitality, acrosome status and intracellular calcium (by flow cytometry) and ability to penetrate oocytes in vitro. Around 2% of sperm were recovered after swim-up, and the replacement of BSA by pOF showed a beneficial reduction of motility parameters calcium concentration, resulting in an increased penetration rate. The combination of albumin and oviductal fluid in the medium did not improve the sperm parameters results, whereas a high concentration of BSA increased sperm morphological abnormalities, motility, and acrosome damage, with a reduction of calcium concentration and penetration rate. In conclusion, the replacement of albumin by preovulatory oviductal fluid in the swim-up sperm preparation method modifies boar sperm parameters and improves the in vitro penetration of oocytes.

Sign in / Sign up

Export Citation Format

Share Document