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2022 ◽  
Author(s):  
Michaela Fenckova ◽  
Villo Muha ◽  
Daniel Mariyappa ◽  
Marica Catinozzi ◽  
Ignacy Czajewski ◽  
...  

O-GlcNAcylation is a reversible co-/post-translational modification involved in a multitude of cellular processes. The addition and removal of O-GlcNAc modification is controlled by two conserved enzymes, O-GlcNAc transferase (OGT) and O-GlcNAc hydrolase (OGA). Mutations in OGT have recently been discovered to cause a novel Congenital Disorder of Glycosylation (OGT-CDG) that is characterized by intellectual disability. The mechanisms by which OGT-CDG mutations affect cognition remain unclear. We manipulated O-GlcNAc transferase and O-GlcNAc hydrolase activity in Drosophila and demonstrate an important role of O-GlcNAcylation in habituation learning and synaptic development at the larval neuromuscular junction. Introduction of patient-specific missense mutations into Drosophila O-GlcNAc transferase using CRISPR/Cas9 gene editing, leads to deficits in locomotor function and habituation learning. The habituation deficit can be corrected by blocking O-GlcNAc hydrolysis, indicating that OGT-CDG mutations affect cognitive function via reduced protein O-GlcNAcylation. This study establishes a critical role for O-GlcNAc cycling and disrupted O-GlcNAc transferase activity in cognitive dysfunction. These findings suggest that blocking O-GlcNAc hydrolysis is a potential treatment strategy for OGT-CDG.


2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Jack D. A. Sharpen ◽  
Brendan Dolan ◽  
Elisabeth E. L. Nyström ◽  
George M. H. Birchenough ◽  
Liisa Arike ◽  
...  

AbstractThe colonic mucus layer is organized as a two-layered system providing a physical barrier against pathogens and simultaneously harboring the commensal flora. The factors contributing to the organization of this gel network are not well understood. In this study, the impact of transglutaminase activity on this architecture was analyzed. Here, we show that transglutaminase TGM3 is the major transglutaminase-isoform expressed and synthesized in the colon. Furthermore, intrinsic extracellular transglutaminase activity in the secreted mucus was demonstrated in vitro and ex vivo. Absence of this acyl-transferase activity resulted in faster degradation of the major mucus component the MUC2 mucin and changed the biochemical properties of mucus. Finally, TGM3-deficient mice showed an early increased susceptibility to Dextran Sodium Sulfate-induced colitis. Here, we report that natural isopeptide cross-linking by TGM3 is important for mucus homeostasis and protection of the colon from inflammation, reducing the risk of colitis.


2022 ◽  
Author(s):  
Freylan Mena ◽  
Seiling Vargas ◽  
Meyer Guevara-Mora ◽  
J. Mauro Vargas-Hernández ◽  
Clemens Ruepert

Abstract The estuarine ecosystem of Laguna Madre de Dios (LMD), in the Caribbean coast of Costa Rica, is exposed to contamination with pesticide residues coming from the upstream agricultural areas. Biomarkers can provide a better indication of the fitness of biota in real mixture exposure scenarios than traditional lethal dose toxicity measurements. Here, we measured biomarkers of biotransformation, oxidative stress and neurotoxicity on Astyanax aeneus, an abundant fish species in LMD. Glutathione S-transferase activity (GST), catalase activity (CAT), lipid peroxidation (LPO), and cholinesterase activity (ChE) were measured in fish collected during seven sampling campaigns, carried out between 2016 and 2018. Pesticide residues were analysed in surface water samples collected every time fish were sampled. Residues of 25 pesticides, including fungicides, insecticides and herbicides, were detected. The biomarkers measured in A. aeneus varied along the sampling moments, however, biotransformation and oxidative stress signals showed coupled responses throughout the assessment. Furthermore, significant correlations were established between three biomarkers (GST, LPO and CAT) and individual pesticides, as well as between GST and LPO with groups of pesticides with shared biocide action. Among pesticides, insecticide residues had a major influence on the responses observed in fish. This work shows that the frequent exposure to environmentally relevant concentrations of pesticides can be related to physiological responses in fish that affect their health. This early warning information should be considered to improve the protection of estuarine ecosystems in the tropics.


Author(s):  
Ranjit S. Ambad ◽  
Suryakant Nagtilak ◽  
Gangaram Bhadarge ◽  
Meghali Kaple

Introduction: Excessive alcohol consumption is a global healthcare problem with enormous social, economic, and clinical consequences, accounting for 3.3 million deaths in 2012. Glutathione (GSH) is tri-peptide thiol with chemical name γ glutamyl-cysteinyl-glycine the properties of glutathione are conferred to it by highly reactive thiol present in one of its constituent amino acids- cysteine, hence they referred as GSH. Xenobiotics form thioether (-S) linkage with GSH. The reaction is catalysed by enzyme known as glutathione S Transferases (GSTs). The cytoplasmic GSTs are important in the xenobiotic metabolism and are present in higher concentration in liver. Materials and Methods: The present study was conducted in the Dept. of Biochemistry in collaboration with Dept. of General Medicine at Datta Meghe Medical College, Nagpur. In present study includes 40 diagnosed alcoholic liver disease patients and 40 non-alcoholic healthy subjects as control group who are permanent nt of study area. Results: The level of GST was raised in chronic alcoholic patients i.e. study group (43.25±15.94) as compare to control group (1.57±0.55). At the other hand the level of total thiol were decreased in study group (3.12±0.55) as compare to control group. Conclusions: The strong negative association between glutathione-s-transferase (GST) and total thiol (T-SH) levels suggested that as the concentration of total thiol (T-SH) decreased, glutathione-s-transferase activity increased (GST). This may be attributed to an increase in alcohol-induced oxidative stress and increased T-SH utilization from thiols.


2021 ◽  
Vol 8 ◽  
Author(s):  
Mingming Han ◽  
Tianheng Gao ◽  
Yuxin Liu ◽  
Zakaria Zuraini ◽  
Chenxi Zhu ◽  
...  

Berberine hydrochloride is an isoquinoline alkaloid, which has antitumoral, antibacterial, and antiviral activities in vivo and in vitro. Charybdis japonica is one of the main economic species of crab in Southeast Asia. We studied the molecular mechanism of oxidative stress in berberine hydrochloride-treated C. japonica infected with Aeromonas hydrophila. C. japonica were infected with A. hydrophila after being submerged in different concentrations (0, 100, 200, and 300 mg/L) of berberine hydrochloride for 48 h. The full-length cDNA of Prx6 and the ORFs of Prx5 and PXL2A were cloned. Prx6 and PXL2A each have one conserved domain, Cys44, and Cys81. The Prx5 conserved domain contains three important Cys loci, Cys75, Cys100, and Cys76. Prx6 was different from Prx5 and PXL2A in the Peroxiredoxin family. The transcription levels of PXL2A infected with A. hydrophila were all higher than the control. The transcription levels of C. japonica were further increased by adding berberine hydrochloride and were increased the highest at a concentration of 300 mg/L. The activities of glutathione peroxidase, superoxide dismutase, and catalase in the hepatopancreas of berberine hydrochloride-treated C. japonica infected with A. hydrophila were significantly increased compared with those only infected with A. hydrophila and the control group. The glutathione transferase activity in the hepatopancreas was significantly increased in berberine hydrochloride-treated C. japonica. The results of this study provide a new understanding of the potential role of berberine hydrochloride on the oxidative stress mechanisms of C. japonica.


2021 ◽  
Vol 8 (4) ◽  
pp. 12-22
Author(s):  
I. A. Goroshinskaya ◽  
E. I. Surikova ◽  
E. M. Frantsiyants ◽  
L. A. Nemashkalova ◽  
P. S. Kachesova ◽  
...  

Purpose of the study. Exploring the erythrocyte glutathione system functioning in patients with gastric cancer in a comparative aspect, depending on tumor histotype and disease prevalence.Patients and methods. The study included 89 patients with gastric cancer, divided into 6 groups depending on the histotype of the tumor. Separately, the results of the study were analyzed in patients with T4 status according to TNM and in patients at stage 4. The content of reduced glutathione and the activity of glutathione-dependent enzymes in the erythrocytes of the patients' blood were studied by conventional spectrophotometric methods. Statistical processing of the results was carried out using the Statistika 6.0 software package according to the Student's t-test and the nonparametric Wilcoxon-Mann-Whitney test for two independent samples.Results. An increase in the content of glutathione was revealed in patients with gastric cancer compared with the group without oncopathology. The maximum increase was observed in patients with low-grade adenocarcinoma - by 42.5 %, while in signet ring cell carcinoma (SRCC) there was only a tendency to increase by 17.8 %. Glutathione reductase activity was decreased in adenocarcinoma by 23.4-26.2 % and did not change in SRCC. The activity of the antioxidant enzymes glutathione peroxidase and glutathione transferase was increased in all groups, and especially in SRCC - by 76 % and 23-29 %, respectively. In patients with the T4 status and at stage IV of the process, a lower activity of the studied glutathione-dependent enzymes was revealed in comparison with all other groups of patients.Conclusions. The data obtained indicate a greater functional potential of the glutathione system in SRCC. A significant increase in glutathione transferase activity at a sufficiently high level of reduced glutathione can contribute to the development of treatment resistance in SRCC patients.


PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260172
Author(s):  
Shawky M. Aboelhadid ◽  
Waleed M. Arafa ◽  
Abdel-Azeem S. Abdel-Baki ◽  
Atalay Sokmen ◽  
Saleh Al-Quraishy ◽  
...  

Globally, the economic losses due to hard ticks infestation and the control of the associated diseases have been calculated at USD $13.9–18.7 billion per year. The economic impact is related to its direct damage to the skins, blood loss, anemia, severe immunological reactions and indirect losses that related to the effects of hemoparasites, cost of treatment for clinical cases and expenses incurred in the control of ticks. The current study evaluated the acaricidal activities of fennel Foeniculum vulgare essential oil and its main components; trans-anethole and fenchone; against R. annulatus. GC–MS analysis revealed that this oil contained 16 components representing 99.9% of the total identified compounds with E-anethole being the predominant component(64.29%), followed by fenchone (9.94%). The fennel oil and trans-anethole showed significant acaricidal activities. The LC50 of the fennel oil was attained at concentrations of 12.96% for adult ticks and 1.75% for tick larvae meanwhile the LC50 of trans-anethole was reached at concentrations of 2.36% for adult tick and 0.56% for tick larvae. On the contrary, fenchone showed no any significant adulticidal activities and its LC50 attained at a concentration of 9.11% for tick larvae. Regarding repellence activities, trans-anethole achieved 100% repellency at the concentration of 10% while fennel showed 86% repellency at the same concentration. Fenchone showed no repellency effect. Treatment of larvae with fennel, trans-anethole, and fenchone LC50 concentrations significantly inhibited the acetylcholinesterase activity. Meanwhile, glutathione s-transferase activity was significantly decreased in fennel treated larvae but no significant effect was found in the larvae of trans-anethole and fenchone groups. These results indicate that the acaricide effect of fennel oil may attributed to its high content of trans-anethole. This was supported by potent adulticidal, larvicidal, and repellency effects of trans-anethole against Rhipeciphalus annulatus tick and therefore it could be included in the list of acaricide of plant origin.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zaoxia Niu ◽  
Lijun Liu ◽  
Yuanyuan Pu ◽  
Li Ma ◽  
Junyan Wu ◽  
...  

AbstractWinter rapeseed (Brassica rapa L.) is a major oilseed crop in Northern China, where its production was severely affected by chilling and freezing stress. However, not much is known about the role of differentially accumulated proteins (DAPs) during the chilling and freezing stress. In this study, isobaric tag for relative and absolute quantification (iTRAQ) technology was performed to identify DAPs under freezing stress. To explore the molecular mechanisms of cold stress tolerance at the cellular and protein levels, the morphological and physiological differences in the shoot apical meristem (SAM) of two winter rapeseed varieties, Longyou 7 (cold-tolerant) and Lenox (cold-sensitive), were explored in field-grown plants. Compared to Lenox, Longyou 7 had a lower SAM height and higher collar diameter. The level of malondialdehyde (MDA) and indole-3-acetic acid (IAA) content was also decreased. Simultaneously, the soluble sugars (SS) content, superoxide dismutase (SOD) activity, peroxidase (POD) activity, soluble protein (SP) content, and collar diameter were increased in Longyou 7 as compared to Lenox. A total of 6330 proteins were identified. Among this, 98, 107, 183 and 111 DAPs were expressed in L7 CK/Le CK, L7 d/Le d, Le d/Le CK and L7 d/L7 CK, respectively. Quantitative real-time PCR (RT-qPCR) analysis of the coding genes for seventeen randomly selected DAPs was performed for validation. These DAPs were identified based on gene ontology enrichment analysis, which revealed that glutathione transferase activity, carbohydrate-binding, glutathione binding, metabolic process, and IAA response were closely associated with the cold stress response. In addition, some cold-induced proteins, such as glutathione S-transferase phi 2(GSTF2), might play an essential role during cold acclimation in the SAM of Brassica rapa. The present study provides valuable information on the involvement of DAPs during cold stress responses in Brassica rapa L, and hence could be used for breeding experiments.


AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Radwa N. Morgan ◽  
Sarra E. Saleh ◽  
Khaled M. Aboshanab ◽  
Hala A. Farrag

AbstractThis work explores the ADP-ribosyltransferase activity of Pseudomonas (P.) aeruginosa exotoxin A using the guanyl hydrazone derivative, nitrobenzylidine aminoguanidine (NBAG) and the impact of gamma radiation on its efficacy. Unlike the conventional detection methods, NBAG was used as the acceptor of ADP ribose moiety instead of wheat germ extract elongation factor 2. Exotoxin A was extracted from P. aeruginosa clinical isolates and screened for toxA gene using standard PCR. NBAG was synthesized using aminoguanidine bicarbonate and 4-nitrobenzaldehyde and its identity has been confirmed by UV, FTIR, Mass and 13C-NMR spectroscopy. The ADP-ribosyl transferase activity of exotoxin A on NBAG in the presence of Nicotinamide adenine dinucleotide (NAD+) was recorded using UV spectroscopy and HPLC. In vitro ADP-ribosyl transferase activity of exotoxin A protein extract was also explored by monitoring its cytotoxicity on Hep-2 cells using sulforhodamine B cytotoxicity assay. Bacterial broths were irradiated at 5, 10, 15, 24 Gy and exotoxin A protein extract activity were assessed post exposure. Exotoxin A extract exerted an ADP-ribosyltransferase ability which was depicted by the appearance of a new ʎmax after the addition of exotoxin A to NBAG/NAD+ mixture, fragmentation of NAD+ and development of new peaks in HPLC chromatograms. Intracellular enzyme activity was confirmed by the prominent cytotoxic effects of exotoxin A extract on cultured cells. In conclusion, the activity of Exotoxin A can be monitored via its ADP-ribosyltransferase activity and low doses of gamma radiation reduced its activity. Therefore, coupling radiotherapy with exotoxin A in cancer therapy should be carefully monitored.


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