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Proteases encoded by SARS-CoV-2 constitute a promising target for new therapies against COVID-19. SARS-CoV-2 main protease (M pro , 3CL pro ) and papain-like protease (PL pro ) are responsible for viral polyprotein cleavage-a process crucial for viral survival and replication. Recently it was shown that 2-phenylbenzisoselenazol-3(2H)-one (ebselen), an organoselenium anti-inflammatory small-molecule drug, is a potent, covalent inhibitor of both the proteases and its potency was evaluated in enzymatic and antiviral assays. In this study, we screened a collection of 34 ebselen and ebselen diselenide derivatives for SARS-CoV-2 PL pro and M pro inhibitors. Our studies revealed that ebselen derivatives are potent inhibitors of both the proteases. We identified three PL pro and four M pro inhibitors superior to ebselen. Independently, ebselen was shown to inhibit the N7-methyltransferase activity of SARS-CoV-2 nsp14 protein involved in viral RNA cap modification. Hence, selected compounds were also evaluated as nsp14 inhibitors. In the second part of our work, we employed 11 ebselen analogues-bis(2-carbamoylaryl)phenyl diselenides-in biological assays to evaluate their anti-SARS-CoV-2 activity in Vero E6 cells. We present their antiviral and cytoprotective activity and also low cytotoxicity. Our work shows that ebselen, its derivatives, and diselenide analogues constitute a promising platform for development of new antivirals targeting the SARS-CoV-2 virus., (© 2023. The Author(s).)

Proteases (proteolytic enzymes) are proteins that catalyze one of the most important biochemical reactions, namely the hydrolysis of the peptide bond in peptide and protein substrates. Therefore these molecular biocatalysts participate in virtually all living processes. The proper balance between intact and processed protease substrates enables to maintenance of homeostasis from a single-cell level to the whole living system. However, when the proteolytic activity is altered, this delicate balance is disturbed, which might lead to the development of a plethora of diseases. Given this, monitoring proteolytic activity is indispensable to understanding how proteases operate in disease lesions and how their altered catalytic activity might be harnessed for a better diagnosis and treatment. In this manuscript, we provide a critical review of the recent development of protease chemical probes which are small molecules that detect proteolytic activity by interacting with protease active site, individual proteases as well as complex proteolytic networks., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Mikolaj Zmudzinski reports financial support was provided by Foundation for Polish Science. Marcin Poreba reports financial support was provided by Foundation for Polish Science. Marcin Drag reports financial support was provided by Foundation for Polish Science., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The main protease of SARS-CoV-2 (M pro ) is the most promising drug target against coronaviruses due to its essential role in virus replication. With newly emerging variants there is a concern that mutations in M pro may alter the structural and functional properties of protease and subsequently the potency of existing and potential antivirals. We explored the effect of 31 mutations belonging to 5 variants of concern (VOCs) on catalytic parameters and substrate specificity, which revealed changes in substrate binding and the rate of cleavage of a viral peptide. Crystal structures of 11 M pro mutants provided structural insight into their altered functionality. Additionally, we show M pro mutations influence proteolysis of an immunomodulatory host protein Galectin-8 (Gal-8) and a subsequent significant decrease in cytokine secretion, providing evidence for alterations in the escape of host-antiviral mechanisms. Accordingly, mutations associated with the Gamma VOC and highly virulent Delta VOC resulted in a significant increase in Gal-8 cleavage. Importantly, IC50s of nirmatrelvir (Pfizer) and our irreversible inhibitor AVI-8053 demonstrated no changes in potency for both drugs for all mutants, suggesting M pro will remain a high-priority antiviral drug candidate as SARS-CoV-2 evolves., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Several chemical approaches have been applied to develop Ub-based substrates and probes selective toward one or a narrow subset of deubiquitinases (DUBs). Since DUBs are highly specific toward ubiquitin and exhibit low activity toward shorter peptides, it is challenging to design truly selective chemical tools to investigate one DUB in biological samples. Incorporating amino acids other than canonical LRG at the P4-P2 positions in the Ub improves DUB activity and selectivity toward Ub derivatives. Here, we describe the protocol for identifying selective peptide sequences using a hybrid combinatorial substrate library (HyCoSuL) approach that can be introduced in the C-terminal motif of Ub. Furthermore, we describe the synthesis protocol of Ub-based probes and substrates containing unnatural amino acids and the application of Ub-based probes to detect DUBs in cell lysates., (© 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused both a health and economic crisis around the world. Its papain-like protease (PLpro) is one of the protein targets utilized in designing new drugs that would aid vaccines in the fight against the virus. Although there are already several potential candidates for a good inhibitor of this protein, the degree of variability of the protein itself is not taken into account. As an RNA virus, SARS-CoV-2 can mutate to a high degree, but PLpro variability has not been studied to date. Based on sequence data available in databases, we analyzed the mutational potential of this protein. We focused on the effect of observed mutations on inhibitors' binding mode and their efficacy as well as protein's activity. Our analysis identifies five mutations that should be monitored and included in the drug design process: P247S, E263D-Y264H and T265A-Y268C., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2022 Perlinska et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Essential oils and aromatic extracts (oleoresins, absolutes, concretes, resinoids) are often used as food flavorings and constituents of fragrance compositions. The flavor and fragrance industry observed significant growth in the sales of some natural materials during the COVID-19 outbreak. Some companies worldwide are making false claims regarding the effectiveness of their essential oils or blends (or indirectly point toward this conclusion) against coronaviruses, even though the available data on the activity of plant materials against highly pathogenic human coronaviruses are very scarce. Our exploratory study aimed to develop pioneering knowledge and provide the first experimental results on the inhibitory properties of hundreds of flavor and fragrance materials against SARS-CoV-2 main and papain-like proteases and the antiviral potential of the most active protease inhibitors. As essential oils are volatile products, they could provide an interesting therapeutic strategy for subsidiary inhalation in the long term., (© 2022. The Author(s).)

More than a year has passed since the world began to fight the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) responsible for the Coronavirus disease 2019 (COVID-19) pandemic, and still it spreads around the world, mutating at the same time. One of the sources of compounds with potential antiviral activity is Traditional Chinese Medicinal (TCM) plants used in China in the supportive treatment of COVID-19. Reynoutria japonica is important part of the Shu Feng Jie Du Granule/Capsule-TCM herbal formula, recommended by China Food and Drug Administration (CFDA) for treatment of patients with H1N1- and H5N9-induced acute lung injury and is also used in China to treat COVID-19, mainly combined with other remedies. In our study, 25 compounds from rhizomes of R. japonica and Reynoutria sachalinensis (related species), were docked into the binding site of SARS-CoV-2 main protease. Next, 11 of them (vanicoside A, vanicoside B, resveratrol, piceid, emodin, epicatechin, epicatechin gallate, epigallocatechin gallate, procyanidin B2, procyanidin C1, procyanidin B2 3,3'-di- O -gallate) as well as extracts and fractions from rhizomes of R. japonica and R. sachalinensis were tested in vitro using a fluorescent peptide substrate. Among the tested phytochemicals the best results were achieved for vanicoside A and vanicoside B with moderate inhibition of SARS-CoV-2 Mpro, IC 50 = 23.10 µM and 43.59 µM, respectively. The butanol fractions of plants showed the strongest inhibition of SARS-CoV-2 Mpro (IC 50 = 4.031 µg/mL for R. sachalinensis and IC 50 = 7.877 µg/mL for R. japonica ). As the main constituents of butanol fractions, besides the phenylpropanoid disaccharide esters (e.g., vanicosides), are highly polymerized procyanidins, we suppose that they could be responsible for their strong inhibitory properties. As inhibition of SARS-CoV-2 main protease could prevent the replication of the virus our research provides data that may explain the beneficial effects of R. japonica on COVID-19 and identify the most active compounds worthy of more extensive research.

In December 2019, the first cases of infection with a novel coronavirus, SARS-CoV-2, were diagnosed. Currently, there is no effective antiviral treatment for COVID-19. To address this emerging problem, we focused on the SARS-CoV-2 main protease that constitutes one of the most attractive antiviral drug targets. We have synthesized a combinatorial library of fluorogenic substrates with glutamine in the P1 position. We used it to determine the substrate preferences of the SARS-CoV and SARS-CoV-2 main proteases. On the basis of these findings, we designed and synthesized a potent SARS-CoV-2 inhibitor (Ac-Abu-DTyr-Leu-Gln-VS, half-maximal effective concentration of 3.7 µM) and two activity-based probes, for one of which we determined the crystal structure of its complex with the SARS-CoV-2 M pro . We visualized active SARS-CoV-2 M pro in nasopharyngeal epithelial cells of patients suffering from COVID-19 infection. The results of our work provide a structural framework for the design of inhibitors as antiviral agents and/or diagnostic tests.

Viral papain-like cysteine protease (PLpro, NSP3) is essential for SARS-CoV-2 replication and represents a promising target for the development of antiviral drugs. Here, we used a combinatorial substrate library and performed comprehensive activity profiling of SARS-CoV-2 PLpro. On the scaffold of the best hits from positional scanning, we designed optimal fluorogenic substrates and irreversible inhibitors with a high degree of selectivity for SARS PLpro. We determined crystal structures of two of these inhibitors in complex with SARS-CoV-2 PLpro that reveals their inhibitory mechanisms and provides a molecular basis for the observed substrate specificity profiles. Last, we demonstrate that SARS-CoV-2 PLpro harbors deISGylating activity similar to SARSCoV-1 PLpro but its ability to hydrolyze K48-linked Ub chains is diminished, which our sequence and structure analysis provides a basis for. Together, this work has revealed the molecular rules governing PLpro substrate specificity and provides a framework for development of inhibitors with potential therapeutic value or drug repurposing., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

Introduction: Obesity and type 2 diabetes mellitus (T2DM) are growing global health concerns associated with significant morbidity, mortality and healthcare expenditures. Due to histories of colonisation and contemporary marginalisation, Canada's Indigenous populations are disproportionately burdened by obesity, T2DM and many other chronic illnesses. Culturally appropriate research on experiences and outcomes of Indigenous patients undergoing bariatric surgery in Canada is scarce. This qualitative study protocol will use a decolonising approach guided by an Indigenous Elder to explore the perspectives and experiences of urban Indigenous Manitobans with respect to T2DM, obesity and bariatric surgery. This knowledge will guide the development and implementation of culturally sensitive bariatric care., Methods and Analysis: Sequential sharing circles (SSCs) and semistructured conversational interviews that have been purposefully designed to be culturally relevant with the guidance of an Indigenous Elder and advisory group (IAG) will be carried out in Winnipeg, Manitoba, Canada. Indigenous adults who are obese (body mass index >35 kg/m 2 ), have T2DM and live in an urban centre will be recruited. Three groups will be investigated: (1) those who have had bariatric surgery; (2) those on the wait list for bariatric surgery and (3) those not associated with a bariatric surgery programme. Each group of 10-12 participants will be guided through a semistructured script led by an Indigenous Elder. Elder-facilitated conversational interviews will also be completed following the SSCs. All content will be audio recorded and transcribed. Thematic analysis will be used to identify emerging patterns using a constructive grounded theory approach., Ethics and Dissemination: This study has received ethical approval from the University of Manitoba Health Research Ethics Board. Findings will inform the development and implementation of culturally sensitive programmes at Manitoba's Centre for Metabolic and Bariatric Surgery. Results will be disseminated in peer-reviewed scientific journals, at obesity and Indigenous health conferences, and knowledge sharing ceremonies., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Deubiquitinating enzymes (DUBs) are responsible for removing ubiquitin (Ub) from its protein conjugates. DUBs have been implicated as attractive therapeutic targets in the treatment of viral diseases, neurodegenerative disorders and cancer. The lack of selective chemical tools for the exploration of these enzymes significantly impairs the determination of their roles in both normal and pathological states. Commercially available fluorogenic substrates are based on the C-terminal Ub motif or contain Ub coupled to a fluorophore (Z-LRGG-AMC, Ub-AMC); therefore, these substrates suffer from lack of selectivity. By using a hybrid combinatorial substrate library (HyCoSuL) and a defined P2 library containing a wide variety of nonproteinogenic amino acids, we established a full substrate specificity profile for two DUBs-MERS PLpro and human UCH-L3. Based on these results, we designed and synthesized Ub-based substrates and activity-based probes (ABPs) containing selected unnatural amino acids located in the C-terminal Ub motif. Biochemical analysis and cell lysate experiments confirmed the activity and selectivity of engineered Ub-based substrates and probes. Using this approach, we propose that for any protease that recognizes Ub and Ub-like substrates, a highly active and selective unnatural substrate or probe can be engineered., (This journal is © The Royal Society of Chemistry 2020.)

Background: Trichobezoars are foreign bodies in the gastrointestinal tract composed of ingested hair. These can develop into large, hard, obstructing objects that are often impossible to remove endoscopically. The size often leads surgeons to remove these via laparotomy or laparoscopic-assisted procedure (midline laparotomy for specimen removal), with few removed completely laparoscopically., Brief Report: We present a case of a 5-year-old female with pica who had symptoms of foul-smelling diarrhea and weight loss and was found to have a massive gastric trichobezoar. The bezoar was removed laparoscopically with pfannensteil incision facilitating specimen extraction. Further, technical aspects of the procedure are discussed., Conclusion: We conclude that there are benefits to using a laparoscopic approach to remove a massive gastric trichobezoar. This includes the use of a Pfannensteil incision rather than a midline laparotomy for specimen removal., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

In December 2019, the first cases of a novel coronavirus infection causing COVID-19 were diagnosed in Wuhan, China. Viral Papain-Like cysteine protease (PLpro, NSP3) is essential for SARS-CoV-2 replication and represents a promising target for the development of antiviral drugs. Here, we used a combinatorial substrate library containing natural and a wide variety of nonproteinogenic amino acids and performed comprehensive activity profiling of SARS-CoV-2-PLpro. On the scaffold of best hits from positional scanning we designed optimal fluorogenic substrates and irreversible inhibitors with a high degree of selectivity for SARS PLpro variants versus other proteases. We determined crystal structures of two of these inhibitors (VIR250 and VIR251) in complex with SARS-CoV-2-PLpro which reveals their inhibitory mechanisms and provides a structural basis for the observed substrate specificity profiles. Lastly, we demonstrate that SARS-CoV-2-PLpro harbors deISGylating activities similar to SARS-CoV-1-PLpro but its ability to hydrolyze K48-linked Ub chains is diminished, which our sequence and structure analysis provides a basis for. Altogether this work has revealed the molecular rules governing PLpro substrate specificity and provides a framework for development of inhibitors with potential therapeutic value or drug repositioning.

A new quill mite species, Neoaulonastus sidorchukae sp. nov. (Acariformes: Syringophilidae), is described from under-tail covert feathers of Leptocoma zeylonica (Linnaeus) (Passeriformes: Nectariniidae) from Sri Lanka. It is the second record of syringophilid mites of the genus Neoaulonastus parasitizing sunbirds.

A new species of quill mite of the family Syringophilidae (Acariformes: Prostigmata), Niglarobia vanelli sp. nov. collected from eight species of the lapwing genus Vanellus (Charadriiformes: Charadriidae), is described: V. vanellus (Linnaeus, 1758) (type host) from Germany, V. gregarius (Pallas, 1771) from Russia, V. senegallus (Linnaeus, 1766), V. albiceps Gould, 1834, V. spinosus (Linnaeus, 1758), V. crassirostris (Hartlaub, 1855), V. lugubris (Lesson, 1826), and V. coronatus (Boddaert, 1783) all from Tanzania. This new species resembles N. cursoriae Skoracki et al., 2006 and differs by having the following features: in females of N. vanelli sp. nov., each medial branch of the peritremes has 3-4 chambers (vs 2 chambers in N. cursoriae); the hysteronotal shield is not fused to the pygidial shield (vs fused); lengths of setae d2 and e2 are 55-65 and 95-120, respectively (vs 115- 140 and 130-160); and setae p' and p" of legs III and IV have 4-6 tines (vs 7 tines).

We investigated the quill mite fauna of the family Syringophilidae (Acariformes: Prostigmata) associated with Sunbirds (Passeriformes: Nectariniidae) in the Sub-Saharan region. Six hundred eleven host individuals belonging to 52 species were examined. Syringophilid parasitization prevalence (44 hosts of 15 species) ranged from 1.4 to 75% in particular host species. In the collected material, we have found seven quill mite species and among them four are new for science: 1) Aulobia afroanthreptes Skoracki & Zmudzinski sp. nov. from Anthreptes neglectus Neumann, 1922 and Anthreptes longuemarei (Lesson, 1831), both from Tanzania; 2) Syringophiloidus nectariniae Skoracki & Zmudzinski sp. nov. from Hedydipna collaris (Vieillot, 1819) from Tanzania; 3) Aulonastus nectariniphilus Skoracki & Zmudzinski sp. nov. from Anthreptes reichenowi Gunning, 1909 from Tanzania and Nectarinia tacazze (Stanley, 1814) from Ethiopia; and 4) Picobia hedydipna Skoracki & Zmudzinski sp. nov. from Hedydipna collaris from Kenya. Representatives of the genera Aulonastus Kethley, 1970 and Syringophiloidus Kethley, 1970 are recorded on Sunbirds for the first time. The following new host species are given: Cinnyris mariquensis Smith, 1836, C. shelleyi Alexander, 1899 and C. regius Reichenov, 1893, all from Tanzania for Aulobia nectariniae Skoracki & Glowska, 2008; A. neglectus and A. longuemarei, both from Tanzania for Neoaulonastus cinnyris Klimovicova et al., 2014; Cyanomitra verreauxii (Smith, 1832) from Tanzania and Cinnyris chalybeus (Linnaeus, 1766) from South Africa for Picobia oritis Skoracki et al., 2009. Additionally, host-parasite relationships are discussed.

A new quill mite species of the family Syringophilidae (Acariformes: Prostigmata: Cheyletoidea) is described from Phimosus infuscatus (Lichtenstein) (Pelecaniformes: Threskiornithidae) in Argentina. Selenonycha insperata n. sp. differs from other species of the genus Selenonycha Kethley, 1970 by the presence of wing-like cuticular projections of coxal fields III-IV situated in front of trochanters (vs absence). An unexpected finding of this species on a bird of the family Threskiornithidae (Pelecaniformes) is discussed as an example of host shift. Additionally, a key to the species of the genus is provided.

A new species of parasitic mite of the family Syringophilidae (Acariformes: Cheyletoidea), Chenophila marmaronetta sp. nov. is described from the secondary quill feathers of Marmaronetta angustirostris (Menetries) (Anseriformes: Anatidae) from Turkey. This species differs from closely related Ch. platyrhynchos Tymcio et al., 2013 by the presence of 9 chambers in each medial branch of the peritremes (vs 5 chambers in Ch. platyrhynchos), length of the stylophore 220-235 (vs 255-275), and lengths of setae vi, ve, d1 and d2 40-55, 65-70, 90-105 and 170, respectively (vs 65-85, 80-100, 130-170 and 85-150).

Background: Varicose vein disease (VVD) affects approximately one third of adults. Cure Conservatrice et Hémodynamique de l'Insuffisance Veineuse en Ambulatoire (CHIVA) is a minimally invasive, vein sparing technique that is emerging as an alternative to ablative techniques for treating VVD., Methods: This prospective study assessed the rate of recurrence of venous reflux with CHIVA. We evaluated 150 primary procedures with clinical and duplex ultrasound examinations pre and post operatively. Patients were followed at <3 months and >1-year post-op. Recurrence was defined as reflux in the diseased vessel at the saphenofemoral junction on duplex examination., Results: There was no documented recurrence at the early follow up. To date, 58 legs have completed the late follow up and reflux was found in 5 legs resulting in a recurrence rate of 8.6%; 95% CI (2.4%, 19%)., Conclusion: Our results indicate that CHIVA appears to offer a promising alternative for the treatment of VVD., (Copyright © 2017. Published by Elsevier Inc.)

The parasitic quill mites of the family Syringophilidae (Acariformes: Prostigmata) are recorded on ibises and spoonbills (Pelecaniformes: Threskiornithidae) for the first time. Four new species of the genus Stibarokris Kethley, 1970 are described: 1) S. theristicus Skoracki, Zmudzinski & Unsoeld sp. nov. ex Theristicus caudatus (Boddaert, 1783) from Brazil, 2) S. geronticus Skoracki, Zmudzinski & Unsoeld sp. nov. ex Geronticus calvus (Boddaert, 1783) from South Africa, 3) S. brevisetosus Skoracki & Zmudzinski sp. nov. ex Plegadis falcinellus (L., 1766) from Turkey, and 4) S. plataleus Skoracki & Zmudzinski sp. nov. ex Platalea leucorodia L., 1758 from Austria. Additionally, a key to all described species in the genus is presented, and hypothesis of the Gondwanan origin of syringophilids associated with ibises and spoonbills is briefly discussed., (© The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com Version of Record, first published online September 19, 2016 with fixed content and layout in compliance with Art. 8.1.3.2 ICZN.)

Quill mite species Picobia caudati Skoracki and Hebda, 2004 collected from its type host Aegithalos caudatus (L.) is recorded from seven new localities in Europe (France, Germany, Italy, Macedonia) and Asia (China, Russia, Japan).

Four accipitriform bird species of the family Accipitridae are reported as new hosts for quill mites (Acari: Cheyletoidea: Syringophilidae): Megasyringophilus aquilus Skoracki, Lontkowski and Stawarczyk, 2010 was collected from Hieraaetus pennatus Gmelin, 1788 in France and Spain, and Buteo jamaicensis Gmelin, 1788 in Canada; Peristerophila accipitridicus Skoracki, Lontkowski and Stawarczyk, 2010 was collected from Circaetus gallicus Gmelin, 1788 in France, and Buteo lagopus Pontoppidan, 1763 in Germany.