Viral neuraminidase is a type of neuraminidase found on the surface of influenza viruses that enables the virus to be released from the host cell. Neuraminidases are enzymes that cleave sialic acid groups from glycoproteins and are required for influenza virus replication. Viral neuraminidases are the members of the Glycoside hydrolase family 34 CAZY GH_34 which comprises enzymes with only one known activity. Neuraminidases cleave the terminal sialic acid residues from carbohydrate chains in glycoproteins. Sialic acid is a negatively charged sugar associated with the protein and lipid portions of lipoproteins. In Influenza virus, neuraminidases prevent self-aggregation by removing the carbohydrate from the viral envelope thus facilitating the mobility of the virus to and from the site of infection. Antiviral agents that inhibit influenza viral neuraminidase activity are of major importance in the control of influenza; when influenza virus replicates, it attaches to the interior cell surface using hemagglutinin, a molecule found on the surface of the virus that binds to sialic acid groups.
Sialic acids are found on various glycoproteins at the host cell surface, the virus exploits these groups to bind the host cell. In order for the virus to be released from the cell, neuraminidase must enzymatically cleave the sialic acid groups from host glycoproteins. Since the cleavage of the sialic groups is an integral part of influenza replication, blocking the function of neuraminidase with neuraminidase inhibitors is an effective way to treat influenza. A single hemagglutinin-neuraminidase protein can combine neuraminidase and hemagglutinin functions, such as in mumps virus and human parainfluenza virus; the enzyme helps viruses to be released after budding from the plasma membrane of a host cell. Influenza virus membranes contain two glycoproteins: neuraminidase. While the hemagglutinin on the surface of the virion is needed for infection, its presence inhibits release of the particle after budding. Viral neuraminidase cleaves terminal neuraminic acid residues from glycan structures on the surface of the infected cell.
This promotes the release of progeny viruses and the spread of the virus from the host cell to uninfected surrounding cells. Neuraminidase cleaves sialic acid residues from viral proteins, preventing aggregation of viruses. Neuraminidase has been targeted in structure-based enzyme inhibitor design programmes that have resulted in the production of two drugs and oseltamivir. Administration of neuraminidase inhibitors is a treatment that limits the severity and spread of viral infections. Neuraminidase inhibitors are useful for combating influenza infection: zanamivir, administered by inhalation. On February 27, 2005, a 14-year-old Vietnamese girl was documented to be carrying an H5N1 influenza virus strain, resistant to the drug oseltamivir; the drug is used to treat patients. However, the Vietnamese girl who had received a prophylactic dose was found to be non-responsive to the medication. In growing fears of a global avian flu pandemic, scientists began to look for a cause of resistance to the Tamiflu medication.
The cause was determined to be a histidine-to-tyrosine substitution at position 274 in its neuraminidase protein. As strains of influenza are continuously mutating, it is essential that scientists and efficiently determine the correct neuraminidase subtype, responsible for the drug resistance in order to develop medications that will combat specific strains of influenza. A new class of neuraminidase inhibitors that covalently attach to the enzyme have shown activity against drug-resistant virus in vitro. In ideal circumstances, influenza virus neuraminidase should act on the same type of receptor the virus hemagglutinin binds to, a phenomenon that does not always happen, it is not quite clear how the virus manages to function when there is no close match between the specificities of NA and HA. Neuraminidase enzymes can have endo- or exo-glycosidase activity, are classified as EC 126.96.36.199 and EC 188.8.131.52. In general, mammalian sialic acid residues are at terminal positions in complex glycans, so viral neuraminidases - which are exo-glycosidase enzymes - use these terminal residues as their substrates.
H5N1 genetic structure Antigenic shift Influenza research Hemagglutinin Influenza Research Database Database of influenza sequences. Proteopedia Influenza Neuraminidase and Relenza Avian Influenza Neuraminidase and Relenza
The Chantry Chapel of St Mary the Virgin, Wakefield, is a chantry chapel in Wakefield, West Yorkshire, is designated a Grade I Listed building by English Heritage. It is located south of the city centre on the medieval bridge over the River Calder, it is the only survivor of four chantries in Wakefield and the oldest and most ornate of the surviving bridge chapels in England. Others are at St Ives, Rotherham and Bradford-on-Avon; the chapel has had three west fronts, the original medieval façade having been removed to Kettlethorpe Hall in 1832. The medieval bridge is a scheduled ancient monument. Wakefield had four chantry chapels, they were built outside the medieval town on the roads leading to Leeds, Dewsbury and Doncaster. The Chantry of St John the Baptist was on Northgate, the road to Leeds, where Wakefield Grammar School stands today; the Chapel of St Mary Magdalene was on Westgate where it crossed the Ings Beck on the road to Dewsbury. St Swithun's Chantry Chapel, on the York road, was near Clarke Hall.
In the 14th century the Chantry Chapel of St Mary the Virgin was built on the medieval bridge across the River Calder on the road to Doncaster and the south. Wakefield's medieval nine-arched bridge is 320 feet long, was built in stone between 1342 and 1356, it replaced an earlier wooden structure on the site of an ancient ford. The chapel on the bridge was licensed in 1356; the Battle of Wakefield was fought about a mile south of the bridge in 1460 and the Earl of Rutland was killed near the bridge while attempting to escape. The chapel was used for worship until the Reformation and Abolition of Chantries Acts when all Wakefield's four chantry chapels were closed; the bridge chapel survived. After closure it was used as a warehouse, library and cheese shop and survived bridge widening in 1758 and 1797; the bridge and its chapel were painted by artists including J. M. W. Turner whose watercolour dates from 1793; the chapel was transferred to the Church of England in 1842 and the Yorkshire Architectural Society, influenced by the Oxford Movement, persuaded to undertake its restoration.
The society, keen to restore medieval ecclesiastical remains, adopted designs by George Gilbert Scott. Restoration costing £2,500, was carried out, resulting in the complete reconstruction of the chapel above pavement level; the new west front differed from its medieval predecessor. Scott is perceived as having made two errors, the first was being persuaded to replace the old west front; the second was having the new façade carved from Caen stone, which crumbled in the polluted urban atmosphere and was replaced in 1939 in gritstone by ecclesiastical architect Sir Charles Nicholson. The original richly carved medieval façade was moved to Kettlethorpe Hall, where it became the frontage to a folly boathouse; the chapel opened for Anglican worship in 1848 and was used as the parish church of the newly formed ecclesiastical district of St Mary until a church was built in 1854. The bridge chapel became services were held irregularly. St Mary's merged with St Andrew's, Eastmoor in the 1960s and the impoverished parish struggled with the chapel's upkeep.
In the 1980s it seemed the chapel would be declared redundant by the Church of England. In January 2000 a parish boundary change brought the chantry into the care of Wakefield Cathedral; the chapel which projects to the east side of the bridge is built into on a small island in the river and its base is a structural element of the bridge. It is rectangular in plan and was built of ashlar sandstone from a quarry at Goodybower; the chapel measures 50 feet by 25 feet. It measures 36 feet to the top of the battlements at the eastern end; the chapel is at street level and has a lower chamber, the sacristy, accessed by a spiral staircase at the east end. The chapel's west front has three narrow doorways, its façade is divided into five elaborately carved panels. The panels represented the Annunciation, the Nativity, the Resurrection, the Ascension and the Coronation of the Virgin but the fifth panel was replaced by the Descent of the Holy Ghost when it was restored. There are three bays with square headed windows with "flamboyant" tracery.
The chapel has octagonal corner pinnacles and at the north eastern corner there is a small embattled octagonal turret with a small bell tower which contained two bells. In the north east corner a newel staircase leads to the roof. A staircase descends to a small crypt in the basement of the building. Four of the seven traceried windows have stained glass, the east window, two south windows and one north window; the "Friends of Wakefield Chantry Chapel" was formed in 1991 by members of the Wakefield Historical Society, Wakefield Civic Society and members of St Andrew's Church to raise funds to repair the chapel roof and re-point the stonework. A programme of conservation work has since been carried out with the approval of English Heritage; the work included re-wiring and the installation of heating. Renewal to the external stonework cost £30,000 in a project by William Anelay Ltd. Six new carved stone heads were made for the south side of the building. At the suggestion of architect David Greenwood, the Bishop of Wakefield, the Lady St Oswald of Nostell Priory, the Rt Hon Walter Harrison and Canon Bryan Ellis allowed their features to be sculpted by stonemason John Schofield.
The fifth head is that of a founder of the Friends, Ray Perraudin, the sixth one of Anelay's workmen. The friends have conserved the internal stone heads. Grade I listed churches in W
Louise Welsh is an English-born author of short stories and psychological thrillers, resident in Glasgow, Scotland. She has written three plays, an opera, edited volumes of prose and poetry, contributed to journals and anthologies. Welsh studied history at Glasgow University and after graduating established and worked at a second-hand bookshop for several years before publishing her first novel. Welsh's debut novel The Cutting Room was nominated for several literary awards including the 2003 Orange Prize for Fiction, it won the Crime Writers' Association Creasey Dagger for the best first crime novel. Welsh's second major work, the novella Tamburlaine Must Die, fictionally recounts the last few days in the life of 16th-century English dramatist and poet Christopher Marlowe, author of Tamburlaine the Great, her third novel, The Bullet Trick, is set in Berlin and Glasgow and narrated from the perspective of magician and conjurer William Wilson. Her fourth novel, Naming the Bones, was published by Canongate Books in March 2010.
Her fifth novel, The Girl on the Stairs is a psychological thriller set in Berlin and published in August 2012 by Hodder & Stoughton. Her sixth novel, A Lovely Way to Burn, came out with Hodder & Stoughton in 2014, in 2015 a sequel, Death is a Welcome Guest was published. In 2009, she donated the short story "The Night Highway" to Oxfam's Ox-Tales project, four collections of UK stories written by 38 authors, her story was published in the'Air' collection. From December 2010 to April 2012, she was the Writer in Residence for the University of Glasgow and Glasgow School of Art. In 2011, Welsh participated in the International Writing Program Fall Residency at the University of Iowa in Iowa City, IA, she contributed, with Zoë Strachan, a short story entitled "Anyone Who Had a Heart" to Glasgow Women's Library's 21 Revolutions Project. 21 Revolutions commissioned 21 writers and 21 artists to create works to celebrate the 21st Birthday of Glasgow Women's Library. She is Honorary President of the Ullapool Book Festival.
Welsh lives in Glasgow with the writer Zoë Strachan, her partner since 1998. REVIEW: A Lovely Way to Burn REVIEW: No Dominion REVIEW: No Dominion