139-454: Sarah Jane Smith is a fictional character played by Elisabeth Sladen in the long-running BBC Television science fiction series Doctor Who and two of its spin-offs . Sarah Jane is a dogged investigative journalist who first encounters alien time traveller the Doctor while trying to break a story on a top secret research facility, and subsequently becomes his travelling companion on
278-520: A Rational Planet , also by Miles, suggest that Sarah Jane married someone named Paul Morley sometime between 1996 and 1998 and took his name. In the short story "Lily" by Jackie Marshall, in Big Finish's Short Trips: A Christmas Treasury , the Fifth Doctor pays a visit to an older Sarah Jane, who has a daughter, Lauren, and an autistic granddaughter, Lily; Lauren's father is named Will. In
417-505: A biography of Sarah Jane from her childhood to the early 1990s. She grew up with her aunt Lavinia after her parents died in a car crash. She went to Caterham School For Girls and the University of Nottingham. She was engaged to Andrew Lofts, an aspiring television journalist; it didn't last. She ended up working with UNIT; her exact duties were never described. In the spring of 1981, she left UNIT after being hospitalized from an accident in
556-517: A cosmic being who makes alterations to the timeline to cause chaos and destruction; he becomes a recurring adversary for Sarah Jane. Sarah Jane finds a new enemy in the Slitheen , a family of criminal aliens originally seen in Doctor Who , and an ally in alien research scientist Professor Rivers ( Floella Benjamin ). Time travel scenes also depict 13-year-old Sarah Jane (Jessica Ashworth), for whom
695-554: A disadvantage in that it does not differentiate infectious and non-infectious viruses and "tests of cure" have to be delayed for up to 21 days to allow for residual viral nucleic acid to clear from the site of the infection. In laboratories many of the diagnostic test for detecting viruses are nucleic acid amplification methods such as PCR. Some tests detect the viruses or their components as these include electron microscopy and enzyme-immunoassays . The so-called "home" or "self"-testing gadgets are usually lateral flow tests , which detect
834-676: A family in the mid-1980s. Sladen returned to the public eye in the 2000s with more Doctor Who related appearances, which culminated in taking a regular lead role in The Sarah Jane Adventures . In 2010, the show earned the Royal Television Society Award for Best Children's Drama. She also made regular guest appearances on the main television series and provided voice-over commentaries and interviews for its releases to DVD. She died of cancer on 19 April 2011. Elisabeth Clara (or Claira) Heath-Sladen
973-441: A greater weight on certain virus properties to maintain family uniformity. A unified taxonomy (a universal system for classifying viruses) has been established. Only a small part of the total diversity of viruses has been studied. As of 2021, 6 realms, 10 kingdoms, 17 phyla, 2 subphyla, 39 classes, 65 orders, 8 suborders, 233 families, 168 subfamilies , 2,606 genera, 84 subgenera , and 10,434 species of viruses have been defined by
1112-541: A leading lady. She also got the occasional part on Radio Leeds and Granada Television , eventually appearing as barmaid Anita Reynolds in 1970 in six episodes of the long-running soap opera Coronation Street . In 1969, she and her husband appeared in the play How the Other Half Loves ; when in the autumn of 1970 the play moved to London , the couple also moved there. Her first television role in London
1251-522: A light microscope, sequencing is one of the main tools in virology to identify and study the virus. Traditional Sanger sequencing and next-generation sequencing (NGS) are used to sequence viruses in basic and clinical research, as well as for the diagnosis of emerging viral infections, molecular epidemiology of viral pathogens, and drug-resistance testing. There are more than 2.3 million unique viral sequences in GenBank. NGS has surpassed traditional Sanger as
1390-661: A new K9 model, K9 Mark IV, and takes her advice by inviting Rose's boyfriend Mickey Smith ( Noel Clarke ) aboard the TARDIS as his second companion. The success of "School Reunion" led to the development of The Sarah Jane Adventures , starring Sladen as Sarah Jane, produced by BBC Wales for CBBC . In The Sarah Jane Adventures , Sarah Jane investigates alien activity covertly from her manor house in Bannerman Road in Ealing , driving an emerald green Nissan Figaro and with
1529-731: A new enemy in the body-stealing alien Androvax (Mark Goldthorp) as well as a lukewarm ally in the form of the interplanetary police force, the Judoon (from Doctor Who ). In the second two-parter , Sarah Jane is able to recover K9 full-time (reflecting a real-world deal struck with the creators of the children's series K-9 ). In a crossover with the parent show, Sarah Jane reveals her intention to marry her secret fiancé, barrister Peter Dalton, in The Wedding of Sarah Jane Smith . However, Dalton's involvement in Sarah Jane's life proves to be
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#17327913220421668-448: A novel pathogen by Martinus Beijerinck (1898) is now acknowledged as being the official beginning of the field of virology as a discipline distinct from bacteriology . He realized the source was neither a bacterial nor a fungal infection , but something completely different. Beijerinck used the word "virus" to describe the mysterious agent in his ' contagium vivum fluidum ' ('contagious living fluid'). Rosalind Franklin proposed
1807-474: A personal level by Mrs Wormwood's claim to be Luke's mother as his creator. Sladen has relatively scarce screen-time in "Sarah Jane-lite" serial The Mark of the Berserker due to back-to-back filming. Though K9 makes no appearances in series two, he appears to assist Sarah Jane against Ambassador Ranius ( Ronnie Corbett ) in a mini-episode for Comic Relief (2009). In series three (2009), Sarah Jane makes
1946-562: A plot by the Rani ( Kate O'Mara ). Though Sladen would not make any more official Doctor Who television appearances until 2006, in the interval the actress reprised her role as Sarah Jane twice on BBC radio with Jon Pertwee, and in a series of Big Finish audio dramas, and in the unofficial direct-to-video spin-off film Downtime (1995) alongside the Brigadier, Second Doctor companion Victoria Waterfield ( Deborah Watling ) and Leeson in
2085-662: A positive reception from BBC executives, the pilot was not picked up for a series due to "logistics and changes in BBC management". Sladen's next appearance in the role was in the 20th anniversary special " The Five Doctors " (1983). She reprised the role in the 1993 Children in Need special Dimensions in Time , and in the 1995 independently produced video Downtime alongside former co-star Nicholas Courtney as Brigadier Lethbridge-Stewart and Deborah Watling as Victoria Waterfield. This
2224-543: A quarry. Afterwards she developed a romantic relationship with Harry Sullivan ; they parted amicably and were still very fond of each other, and were still close friends, even to the time of the article. She wrote science fiction novels World War Skaro and The Monster at the End of Space which made it onto the Times and New York Times bestseller lists. Though there are as yet no original Sarah Jane Adventures novels, many of
2363-545: A rare on-screen role. Following Russell T Davies ' 2005 Doctor Who revival , Sladen returned to the show in the Series 2 episode " School Reunion " (2006). "School Reunion" revisits Sarah Jane, still working alongside K9 since "The Five Doctors", when she encounters the Tenth Doctor ( David Tennant ) while they both investigate mysterious goings on at a school run by Headmaster Finch ( Anthony Head ). Exposition in
2502-411: A rather helpless hysteric to being a feisty, opinionated, strong equal to The Doctor. And, at the time, you know that was quite an extraordinary thing to do. That was not the role the companion, or women, were meant to be playing. They were meant to be playing the victim, they were meant to be decoration. I think what Lis Sladen did with that character is quite extraordinary. We forget how revolutionary she
2641-510: A scheme of The Trickster. The Doctor gatecrashes the wedding to foil The Trickster's plot to make Sarah Jane give up on alien hunting, and explains to Sarah Jane that The Trickster is a powerful member of the extra-dimensional so-called Pantheon of Discord. The serial clarifies that Sarah Jane owes her independent wealth to her Aunt Lavina's will. In 'Sarah-lite' two-parter Mona Lisa's Revenge , Sarah Jane and Luke have their first argument as he progresses into his teenage years ; they argue about
2780-463: A second 12-episode series in late 2008, which carried that same format for the show's third and fourth series up until November 2010. A fifth series originally comprising 12 episodes was commissioned for a late 2011 broadcast, with 6 of the episodes being filmed alongside the show's fourth series, but due to Sladen's unexpected death in April 2011, the latter half never reached production, officially ending
2919-429: A second batch of auditions and saw Elisabeth Sladen after a recommendation from fellow BBC producer Bill Slater, who had twice cast the actress recently in separate episodes of Z-Cars . Sladen performed her audition alongside actor Stephen Thorne and after impressing Letts, he arranged for her to meet Pertwee before any decisions were made. Pertwee stood behind Sladen and gave a 'thumbs-up' to Letts who then offered her
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#17327913220423058-424: A series of adventures spanning the breadth of space and time. After travelling with The Doctor in four seasons of the show they suddenly part ways, and after this she continues to investigate strange goings-on back on Earth . Over time, Sarah Jane establishes herself as a committed defender of Earth from alien invasions and other threats, occasionally reuniting with The Doctor in the course of her own adventures, all
3197-516: A series of science fiction novels. These featured an extraterrestrial called The Doctor and his companion Nicola Jones, who frequently encountered WIN (World Investigative Network), commanded by General Lutwidge-Douglas. Titles included Day of the Dinosaurs , Sutekh the Destroyer and The North Sea Monster . Another in-universe article was written by Kevin W. Parker, Roving Reporter, which was
3336-528: A silent farewell to Luke and to Sarah Jane. In the fourth season (2010) of The Sarah Jane Adventures , Sarah Jane sees Luke off to university in the first two-parter of the series, but continues her adventures alongside Rani and Clyde. The trio encounter the Eleventh Doctor ( Matt Smith ), as well as Sarah Jane's immediate predecessor as The Doctor's companion, Jo Grant ( Katy Manning ), in Death of
3475-551: A similar filter. In the early 20th century, the English bacteriologist Frederick Twort discovered a group of viruses that infect bacteria, now called bacteriophages (or commonly 'phages'), and the French-Canadian microbiologist Félix d'Herelle described viruses that, when added to bacteria on an agar plate , would produce areas of dead bacteria. He accurately diluted a suspension of these viruses and discovered that
3614-456: A solution passed through it. In 1892, the Russian biologist Dmitri Ivanovsky used this filter to study what is now known as the tobacco mosaic virus : crushed leaf extracts from infected tobacco plants remained infectious even after filtration to remove bacteria. Ivanovsky suggested the infection might be caused by a toxin produced by bacteria, but he did not pursue the idea. At the time it
3753-401: A statistical probability such as the volume of the test sample needed to ensure 50% of the hosts cells, plants or animals are infected. This is called the median infectious dose or ID 50 . Infective bacteriophages can be counted by seeding them onto "lawns" of bacteria in culture dishes. When at low concentrations, the viruses form holes in the lawn that can be counted. The number of viruses
3892-460: A top speed of around 100,000 rpm, are and this difference is used in a method called differential centrifugation . In this method the larger and heavier contaminants are removed from a virus mixture by low speed centrifugation. The viruses, which are small and light and are left in suspension, are then concentrated by high speed centrifugation. Following differential centrifugation, virus suspensions often remain contaminated with debris that has
4031-581: A two-year stint as a presenter for the children's programme Stepping Stones , a lead role with Miller playing her husband in ITV drama Send in the Girls , a BBC Play for Today , a role as a stand-up comic's spouse in Take My Wife , and a small part in the film Silver Dream Racer as a bank secretary in 1980, only her second film appearance. In 1981, former Doctor Who producer Barry Letts cast her as
4170-675: Is virus classification . It is artificial in that it is not based on evolutionary phylogenetics but it is based shared or distinguishing properties of viruses. It seeks to describe the diversity of viruses by naming and grouping them on the basis of similarities. In 1962, André Lwoff , Robert Horne , and Paul Tournier were the first to develop a means of virus classification, based on the Linnaean hierarchical system. This system based classification on phylum , class , order , family , genus , and species . Viruses were grouped according to their shared properties (not those of their hosts) and
4309-516: Is a broad subject covering biology, health, animal welfare, agriculture and ecology. Louis Pasteur was unable to find a causative agent for rabies and speculated about a pathogen too small to be detected by microscopes. In 1884, the French microbiologist Charles Chamberland invented the Chamberland filter (or Pasteur-Chamberland filter) with pores small enough to remove all bacteria from
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4448-436: Is a subfield of microbiology that focuses on their detection, structure, classification and evolution, their methods of infection and exploitation of host cells for reproduction, their interaction with host organism physiology and immunity, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy. The identification of the causative agent of tobacco mosaic disease (TMV) as
4587-472: Is also dependent on the size of area that the user is counting. A larger area will require more time but can provide a more accurate representation of the sample. Results of the FFA are expressed as focus forming units per milliliter, or FFU/ When an assay for measuring the infective virus particle is done (Plaque assay, Focus assay), viral titre often refers to the concentration of infectious viral particles, which
4726-670: Is confirmed that Sarah Jane has passed away. In the episode, the newly bi-generated Fifteenth Doctor reminisces with the Fourteenth Doctor about all the loss that they have suffered up to that point in their lives. Amongst the names and events mentioned, the Fifteenth Doctor mentions that Sarah Jane is gone and both Doctors express their love for her. In the Tales of the TARDIS spin-off episode "The Pyramid of Mars",
4865-634: Is different from the total viral particles. Viral load assays usually count the number of viral genomes present rather than the number of particles and use methods similar to PCR . Viral load tests are an important in the control of infections by HIV. This versatile method can be used for plant viruses. Molecular virology is the study of viruses at the level of nucleic acids and proteins. The methods invented by molecular biologists have all proven useful in virology. Their small sizes and relatively simple structures make viruses an ideal candidate for study by these techniques. For further study, viruses grown in
5004-406: Is formed. The FFA is particularly useful for quantifying classes of viruses that do not lyse the cell membranes, as these viruses would not be amenable to the plaque assay. Like the plaque assay, host cell monolayers are infected with various dilutions of the virus sample and allowed to incubate for a relatively brief incubation period (e.g., 24–72 hours) under a semisolid overlay medium that restricts
5143-568: Is no longer content to live alone; she discloses she never married after parting from the Fourth Doctor , to whom no one could ever compare. Sometime between "School Reunion" and "Invasion of the Bane", K9 has left Sarah Jane to close off a black hole , occasionally passing close enough to contact her; due to the concurrent development of the K-9 television series , to which creator Bob Baker owns
5282-435: Is particularly useful when studying the genetics of viruses that have segmented genomes (fragmented into two or more nucleic acid molecules) such as influenza viruses and rotaviruses . The genes that encode properties such as serotype can be identified in this way. Often confused with reassortment, recombination is also the mixing of genes but the mechanism differs in that stretches of DNA or RNA molecules, as opposed to
5421-411: Is relatively inert but easily self-forms a gradient when centrifuged at high speed in an ultracentrifuge. Buoyant density centrifugation can also be used to purify the components of viruses such as their nucleic acids or proteins. The separation of molecules based on their electric charge is called electrophoresis . Viruses and all their components can be separated and purified using this method. This
5560-407: Is slowly dying from radiation poisoning , he makes timely visits to his close friends and companions; The Doctor saves Luke's life from an oncoming car on Bannerman Road (an inside joke by Russell T Davies commenting on actors' failure to look for cars before crossing the street because traffic is always stopped for them, something that he believes is especially important in a children’s show) and bids
5699-451: Is the first time that BBC Audiobooks have commissioned new content for exclusive release on audio. Further pairs of audio stories were released every year until 2010, again all read by Sladen. In 2011, two audio stories were read by Daniel Anthony and Anjii Mohindra. Sladen's daughter Sadie Miller took over the role of Sarah Jane Smith for Big Finish audio dramas in 2021, first in Return of
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5838-500: Is then expressed as plaque forming units . For the bacteriophages that reproduce in bacteria that cannot be grown in cultures, viral load assays are used. The focus forming assay (FFA) is a variation of the plaque assay, but instead of relying on cell lysis in order to detect plaque formation, the FFA employs immunostaining techniques using fluorescently labeled antibodies specific for a viral antigen to detect infected host cells and infectious virus particles before an actual plaque
5977-429: Is usually done in a supporting medium such as agarose and polyacrylamide gels . The separated molecules are revealed using stains such as coomasie blue , for proteins, or ethidium bromide for nucleic acids. In some instances the viral components are rendered radioactive before electrophoresis and are revealed using photographic film in a process known as autoradiography . As most viruses are too small to be seen by
6116-571: Is very sensitive and specific, but can be easily compromised by contamination. Most of the tests used in veterinary virology and medical virology are based on PCR or similar methods such as transcription mediated amplification . When a novel virus emerges, such as the covid coronavirus, a specific test can be devised quickly so long as the viral genome has been sequenced and unique regions of the viral DNA or RNA identified. The invention of microfluidic tests as allowed for most of these tests to be automated, Despite its specificity and sensitivity, PCR has
6255-509: The 2006 series , along with David Tennant as the Tenth Doctor . Sladen worked a lot of the characterisation herself—in the lead-up to the broadcast of "School Reunion" she was quoted in the Daily Mirror as saying: "Sarah Jane used to be a bit of a cardboard cut-out. Each week it used to be, 'Yes Doctor, no Doctor', and you had to flesh your character out in your mind—because if you didn't, no one else would." She also spoke favourably of
6394-516: The Fourth . She returned to the character of Sarah Jane Smith on several later occasions. In 1981, new Doctor Who producer John Nathan-Turner asked her to return to the series to ease the transition between Tom Baker and new Doctor Peter Davison . She declined but accepted his second offer of a pilot for a spin-off series called K-9 and Company , co-starring K-9 , the robot dog from Doctor Who . Although it won viewing figures of 8.4 million and
6533-665: The Liverpool Playhouse repertory company as an assistant stage manager. Her first stage appearance at the Playhouse was as a maid in Twelfth Night . A few months later, she played a corpse in The Physicists . However, she was scolded for giggling on stage due to her future husband Brian Miller whispering the words "Respiration nil, Aston Villa two" in her ear while he was playing a doctor. Sladen
6672-643: The Past Doctor Adventures novel Bullet Time by David A. McIntee , all taking place after she stops travelling with The Doctor. She appears in Ian Marter's Harry Sullivan's War published by Target Books; Marter played companion Harry Sullivan in seven television serials. Different accounts of Sarah Jane's life have been given in the Doctor Who literature. Interference and the Virgin New Adventures novel Christmas on
6811-433: The film clips of people who had died in the past year , Sladen was the final person to be shown. Singer-songwriter Talis Kimberley wrote a tribute song, "Goodnight, Sarah-Jane". Tom Baker paid tribute to Sladen on his official website saying "sweet memories of happy days with Lis Sladen, the lovely, witty, kind and so talented Lis Sladen". Virology Virology is the scientific study of biological viruses . It
6950-748: The 1993 documentary, Thirty Years in the TARDIS , wearing a replica of the Andy Pandy overalls Sladen wore in The Hand of Fear . Sladen was diagnosed with pancreatic cancer in February 2011 and died on 19 April 2011; she had previously fought the disease in 1999. She was 65. Her death was widely reported in the UK—on the BBC Ten O'Clock News; as one of the rolling headlines of the BBC News channel for
7089-484: The 30th-anniversary story Dimensions in Time (1993), then co-starred in two BBC radio serials with the Third Doctor ( The Paradise of Death and The Ghosts of N-Space ), and starred in a series of spin-off audio dramas entitled Sarah Jane Smith for independent production company Big Finish. After the television revival of Doctor Who in 2005, she appears in several episodes with the Tenth Doctor , and as
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#17327913220427228-646: The Cybermen in March, a reworking of Gerry Davis' 1974 original script which was eventually filmed as Revenge of the Cybermen , with Tom Baker as the fourth Doctor; and then in The Third Doctor Adventures in May, with Tim Treloar as the third Doctor. The canonicity of Sarah Jane's appearances in the audio dramas is, like all Doctor Who spin-off media, unclear, and they may not even take place in
7367-458: The Doctor ; aliens known as the Shansheeth fake The Doctor's death as part of a plot to gain access to the TARDIS using Jo and Sarah Jane's memories. The Empty Planet is this series' 'Sarah-lite' serial; with the rest of the population, Sarah Jane mysteriously vanishes, leaving Rani and Clyde to investigate without her. In Lost in Time , Sarah Jane is sent back in time on a mission from
7506-577: The Fifteenth Doctor tells his companion Ruby Sunday ( Millie Gibson ) about Sarah Jane and that they were best friends and told her that she travelled with him during his first encounter with Sutekh. It is later revealed that the conversation took place during the events of " Empire of Death ". Sarah Jane appears in several Doctor Who novels and short stories, notably in the Eighth Doctor Adventures novels Interference: Book One and Interference: Book Two by Lawrence Miles ; and
7645-550: The Future , and appeared in 15 episodes of the BBC schools programme Numbertime , which was repeated annually for around ten years. This was her last television acting appearance until the 2006 Doctor Who episode " School Reunion ". In 2008 and 2009, Sladen appeared in a pantomime production of Peter Pan at the Theatre Royal Windsor , playing Mrs. Darling and a beautiful mermaid . Sladen's last fan event
7784-681: The Game of Rassilon in The Death Zone devised by Time Lord founder Rassilon (Richard Mathews). Here, Sarah is reunited with the Third Doctor, and also meets the First , Second and Fifth . "The Five Doctors" shows that Sarah Jane still owns and is working with K9. The character made an appearance in the 1993 Children in Need special (a crossover with long-running British soap EastEnders ), Dimensions in Time , wherein various Doctors and companions are teleported to Albert Square as part of
7923-616: The Past Doctor Adventure Bullet Time , Sarah Jane is apparently killed—although the story is ambiguous about whether she actually dies—in 1997 when she sacrifices herself so that she cannot be used as a hostage to stop the Seventh Doctor from taking action to aid an escaping alien ship, contradicting her other spin-off appearances. However, the novel takes place during a story arc where enemies of The Doctor were attempting to eliminate his companions from
8062-452: The Season 14 serial The Hand of Fear (1976) after The Doctor receives a summons to his home planet, Gallifrey . Sladen has described Sarah as "a bit of a cardboard cut-out. Each week it used to be, 'Yes Doctor, no Doctor'..." Following her tenure as a companion, Sladen reprised the role of Sarah Jane in a pilot episode for an Earth-based spin-off series, K-9 and Company , in 1981. In
8201-609: The Timeline (revealed in the later novel Sometime Never... ), and Sarah Jane's death may have been reversed when those enemies are defeated. In any case, other stories have shown her alive after 1997. Sarah Jane was mentioned in the prologue of the Virgin Publishing novelisation of The Power of the Daleks by John Peel. It revealed that Sarah Jane was working as UNIT 's official chronicler and that in "1996" she covered
8340-764: The aftermath of the Cybermen 's failed attempt to drain Earth of its energy and the technology left behind in their wake ( The Tenth Planet , which was actually set in 1986). Stories written as in-universe articles in Doctor Who Magazine Winter Special 1991 (subtitled "UNIT Exposed"), made statements about Sarah Jane's life after leaving the Fourth Doctor. She wrote a history of UNIT, Fighting for Humankind ("heavily vetted and evidently subjected to considerable censorship"), as well as
8479-416: The antibodies they react with. The use of the antibodies which were once exclusively derived from the serum (blood fluid) of animals is called serology . Once an antibody–reaction has taken place in a test, other methods are needed to confirm this. Older methods included complement fixation tests , hemagglutination inhibition and virus neutralisation . Newer methods use enzyme immunoassays (EIA). In
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#17327913220428618-459: The central character of her own series The Sarah Jane Adventures from 2007 to 2011, which included appearances by both the Tenth and Eleventh Doctors . In April 2020, former Doctor Who showrunner Russell T Davies released an epilogue to Sarah Jane's story on the anniversary of Sladen's death, detailing various characters attending Sarah's funeral. Doctor Who producer Barry Letts offered
8757-489: The centrifugation. In some cases, preformed gradients are used where solutions of steadily decreasing density are carefully overlaid on each other. Like an object in the Dead Sea , despite the centrifugal force the virus particles cannot sink into solutions that are more dense than they are and they form discrete layers of, often visible, concentrated viruses in the tube. Caesium chloride is often used for these solutions as it
8896-597: The character was given her own television series, The Sarah Jane Adventures , detailed above. There are loose allusions to the audio series in the television series, including Sarah Jane's ownership of a Volkswagen. Sarah Jane appears in two audio stories based on The Sarah Jane Adventures , released in November 2007 on CD : The Glittering Storm by Stephen Cole and The Thirteenth Stone by Justin Richards , with both stories read by series star Elisabeth Sladen . This
9035-593: The characterisation in the new series. Sladen won best guest appearance in the annual Cult TV Awards. Following her successful appearance in the series, Sladen later starred in The Sarah Jane Adventures , a Doctor Who spin-off focusing on Sarah Jane, produced by BBC Wales for CBBC and created by Russell T Davies . A 60-minute special aired on New Year's Day 2007, with a 10-episode series commencing broadcast in September 2007, followed by
9174-601: The cleanliness of Luke's room. In series finale The Gift , though she is reluctant to use weapons or cause harm, when Luke falls deathly ill for the first time ever due to the machinations of the Blathereen-Slitheen, Sarah Jane takes up arms to confront them. In the episode's conclusion, regretfully she is forced to kill them using Mr Smith. Sarah Jane next appears in the Tenth Doctor two-part Doctor Who finale, " The End of Time ", in 2010. When The Doctor
9313-477: The day; featuring prominently on many commercial television news reports (including Granada which serves her native Liverpool); on the front page of the Daily Mirror and the Liverpool Echo ; and in the obituary features of almost every UK newspaper. The first episode of the sixth series of Doctor Who , " The Impossible Astronaut ", aired on the following Saturday, and opened with a screen dedicating
9452-646: The death of her best friend Andrea Yates ( Jane Asher ) gave Sarah Jane her resolve to fight against loss of life. Sarah Jane then reappears in Doctor Who in the two-part fourth series finale episodes " The Stolen Earth " and " Journey's End " (2008), which crosses over from Torchwood and The Sarah Jane Adventures . When Daleks invade Earth, Sarah Jane is summoned along with UNIT officer Martha Jones ( Freema Agyeman ) and Torchwood leader Captain Jack Harkness ( John Barrowman ) by former PM Harriet Jones ( Penelope Wilton ) to help The Doctor save
9591-405: The determination of the structure of viruses. Viruses are obligate intracellular parasites and because they only reproduce inside the living cells of a host these cells are needed to grow them in the laboratory. For viruses that infect animals (usually called "animal viruses") cells grown in laboratory cell cultures are used. In the past, fertile hens' eggs were used and the viruses were grown on
9730-543: The detrimental effect they have on the host cell. These cytopathic effects are often characteristic of the type of virus. For instance, herpes simplex viruses produce a characteristic "ballooning" of the cells, typically human fibroblasts . Some viruses, such as mumps virus cause red blood cells from chickens to firmly attach to the infected cells. This is called "haemadsorption" or "hemadsorption". Some viruses produce localised "lesions" in cell layers called plaques , which are useful in quantitation assays and in identifying
9869-428: The documented species of animal, plant, and bacterial viruses were discovered during these years. In 1957 equine arterivirus and the cause of bovine virus diarrhoea (a pestivirus ) were discovered. In 1963 the hepatitis B virus was discovered by Baruch Blumberg , and in 1965 Howard Temin described the first retrovirus . Reverse transcriptase , the enzyme that retroviruses use to make DNA copies of their RNA,
10008-405: The environment, are used in phage display techniques for screening proteins DNA sequences. They are a powerful tool in molecular biology. All viruses have genes which are studied using genetics . All the techniques used in molecular biology, such as cloning, creating mutations RNA silencing are used in viral genetics. Reassortment is the switching of genes from different parents and it
10147-627: The episode reveals that, having waited years for The Doctor to return to her, Sarah Jane assumed he had died, though later came to suspect his involvement when witnessing the alien spaceship above London in Doctor Who Christmas special " The Christmas Invasion ". On meeting Sarah Jane, current companion Rose Tyler ( Billie Piper ) reflects on her future after The Doctor. Though K9 Mark III still assists Sarah Jane, he has fallen into disrepair; after K9 Mark III sacrifices himself to save Sarah Jane and The Doctor, The Doctor leaves Sarah Jane
10286-498: The episode to her memory. A special programme - My Sarah Jane: A Tribute to Elisabeth Sladen - was aired on CBBC immediately afterwards. In 2012 the new companion, Jenna Coleman 's character, was named Clara . This was interpreted by some fans as a tribute to Sladen, as her middle name was Clara. The Hand of Fear was also shown on BBC Four as a tribute. At the British Academy of Film and Television Arts , during
10425-667: The female lead in the BBC Classics production of Gulliver in Lilliput . The character of Lady Flimnap was written for Sladen, and she said it was her favourite role. She continued to appear in various television adverts and in another Letts production, Alice in Wonderland (playing the Dormouse). After the birth of her daughter Sadie in 1985, Sladen went into semi-retirement, placing her family first, but found time for
10564-409: The final caption: "And the story goes on... forever." The cast and writers of The Sarah Jane Adventures produced a special 2020 webcast epilogue for the show with a mix of narrated and acted elements entitled "Farewell, Sarah Jane". In the story, Sarah Jane's friends and many past companions of the Doctor return to London to attend her funeral. In the 60th Anniversary special , " The Giggle ", it
10703-515: The first ever BBC Enterprises audio spin-off from Doctor Who : a cassette and LP release of an abridged version of Genesis of the Daleks , narrated by Baker. Sarah Jane (played by Sladen) appeared in two BBC Radio plays starring Jon Pertwee as The Doctor in the 1990s: The Paradise of Death and The Ghosts of N-Space . She also appears, voiced by Sladen, in her own range of Big Finish audio dramas, consisting of nine stories released between 2002 and 2006. This series came to an unexpected end when
10842-469: The first time in the 1930s when electron microscopes were invented. These microscopes use beams of electrons instead of light, which have a much shorter wavelength and can detect objects that cannot be seen using light microscopes. The highest magnification obtainable by electron microscopes is up to 10,000,000 times whereas for light microscopes it is around 1,500 times. Virologists often use negative staining to help visualise viruses. In this procedure,
10981-455: The first virus to be grown without using solid animal tissue or eggs. This work enabled Hilary Koprowski , and then Jonas Salk , to make an effective polio vaccine . The first images of viruses were obtained upon the invention of electron microscopy in 1931 by the German engineers Ernst Ruska and Max Knoll . In 1935, American biochemist and virologist Wendell Meredith Stanley examined
11120-571: The form of Sky Smith (Sinead Michael), a genetically-engineered alien girl with abilities relating to electromagnetism; the Shopkeeper arranged for their encounter, but declines to explain his motives to Sarah Jane. Sarah Jane's final broadcast appearance comes in series five finale The Man Who Never Was . The final story ends with a short montage of archive footage and audio recordings celebrating Sarah Jane's journey from lone investigator to mother of two surrounded by friends. The series ends with
11259-590: The full molecules, are joined during the RNA or DNA replication cycle. Recombination is not as common as reassortment in nature but it is a powerful tool in laboratories for studying the structure and functions of viral genes. Reverse genetics is a powerful research method in virology. In this procedure complementary DNA (cDNA) copies of virus genomes called "infectious clones" are used to produce genetically modified viruses that can be then tested for changes in say, virulence or transmissibility. A major branch of virology
11398-650: The full structure of the tobacco mosaic virus in 1955. One main motivation for the study of viruses is because they cause many infectious diseases of plants and animals. The study of the manner in which viruses cause disease is viral pathogenesis . The degree to which a virus causes disease is its virulence . These fields of study are called plant virology , animal virology and human or medical virology . Virology began when there were no methods for propagating or visualizing viruses or specific laboratory tests for viral infections. The methods for separating viral nucleic acids ( RNA and DNA ) and proteins , which are now
11537-438: The full structure of the virus in 1955. In the same year, Heinz Fraenkel-Conrat and Robley Williams showed that purified tobacco mosaic virus RNA and its protein coat can assemble by themselves to form functional viruses, suggesting that this simple mechanism was probably the means through which viruses were created within their host cells. The second half of the 20th century was the golden age of virus discovery, and most of
11676-563: The help of her sentient supercomputer Mr Smith (voice of comedian Alexander Armstrong ), as well as an alien activity scanner and sonic lipstick device . In the special premiere episode " Invasion of the Bane " (2007), Sarah Jane adopts a son: Bane creation, genetic archetype and boy genius Luke Smith ( Tommy Knight ), and befriends her neighbour Maria Jackson ( Yasmin Paige ) during her investigation of Bane leader Mrs Wormwood ( Samantha Bond ). Sarah Jane remarks that since meeting them she
11815-428: The high vacuum inside the electron microscope and the electron beam itself is destructive. In cryogenic electron microscopy the structure of viruses is preserved by embedding them in an environment of vitreous water . This allows the determination of biomolecular structures at near-atomic resolution, and has attracted wide attention to the approach as an alternative to X-ray crystallography or NMR spectroscopy for
11954-510: The highest dilutions (lowest virus concentrations), rather than killing all the bacteria, formed discrete areas of dead organisms. Counting these areas and multiplying by the dilution factor allowed him to calculate the number of viruses in the original suspension. Phages were heralded as a potential treatment for diseases such as typhoid and cholera , but their promise was forgotten with the development of penicillin . The development of bacterial resistance to antibiotics has renewed interest in
12093-406: The laboratory need purifying to remove contaminants from the host cells. The methods used often have the advantage of concentrating the viruses, which makes it easier to investigate them. Centrifuges are often used to purify viruses. Low speed centrifuges, i.e. those with a top speed of 10,000 revolutions per minute (rpm) are not powerful enough to concentrate viruses, but ultracentrifuges with
12232-578: The lives of her parents, Eddie ( Christopher Pizzey ) and Barbara ( Rosanna Lavelle ) in 1951; by doing so she plays into The Trickster's hands, creating a post-apocalyptic alternative universe in the present day. Learning of this however, her parents choose to die, becoming heroes to restore the timeline. In series two finale Enemy of the Bane , Sarah Jane's old friend Brigadier Lethbridge-Stewart (Nicholas Courtney) from UNIT assists her against united adversaries Mrs Wormwood and Sontaran Commander Kaagh ( Anthony O'Donnell ). Sarah Jane feels threatened on
12371-404: The mainstay of virology, did not exist. Now there are many methods for observing the structure and functions of viruses and their component parts. Thousands of different viruses are now known about and virologists often specialize in either the viruses that infect plants, or bacteria and other microorganisms , or animals. Viruses that infect humans are now studied by medical virologists. Virology
12510-471: The membranes surrounding the embryo. This method is still used in the manufacture of some vaccines. For the viruses that infect bacteria, the bacteriophages , the bacteria growing in test tubes can be used directly. For plant viruses, the natural host plants can be used or, particularly when the infection is not obvious, so-called indicator plants, which show signs of infection more clearly. Viruses that have grown in cell cultures can be indirectly detected by
12649-461: The more traditional hierarchy. Starting in 2018, the ICTV began to acknowledge deeper evolutionary relationships between viruses that have been discovered over time and adopted a 15-rank classification system ranging from realm to species. Additionally, some species within the same genus are grouped into a genogroup . The ICTV developed the current classification system and wrote guidelines that put
12788-432: The most common ones are laboratory modified plasmids (small circular molecules of DNA produced by bacteria). The viral nucleic acid, or a part of it, is inserted in the plasmid, which is the copied many times over by bacteria. This recombinant DNA can then be used to produce viral components without the need for native viruses. The viruses that reproduce in bacteria, archaea and fungi are informally called "phages", and
12927-405: The most popular approach for generating viral genomes. Viral genome sequencing as become a central method in viral epidemiology and viral classification . Data from the sequencing of viral genomes can be used to determine evolutionary relationships and this is called phylogenetic analysis . Software, such as PHYLIP , is used to draw phylogenetic trees . This analysis is also used in studying
13066-467: The mysterious Shopkeeper ( Cyril Nri ). Sarah Jane is convinced to retire by an alien plot in the series finale , earning a new nemesis and doppelgänger in Ruby White ( Julie Graham ); she is saved from Ruby when Luke drives down from university to her rescue. Sladen's death ended the show in the middle of its fifth series, which aired in 2011. In its premiere story , Sarah Jane adopts a new child in
13205-745: The occasional television appearance. In 1991, she starred as Alexa opposite Colin Baker in The Stranger audio adventure The Last Mission for BBV Audio. Sladen also appeared in a Bernice Summerfield audio drama, Kate Orman 's Walking to Babylon . Following the audio production of The Paradise of Death in 1993, Sladen restarted her regular public appearances in the United Kingdom. In 1995, she played Dr Pat Hewland in four episodes of Peak Practice . In 1996, she played Sophie in Faith in
13344-403: The ones that infect bacteria – bacteriophages – in particular are useful in virology and biology in general. Bacteriophages were some of the first viruses to be discovered, early in the twentieth century, and because they are relatively easy to grow quickly in laboratories, much of our understanding of viruses originated by studying them. Bacteriophages, long known for their positive effects in
13483-400: The other would signal a thumbs-up. The role of Sarah Jane Smith was originally given to comic actress April Walker , but allegedly during rehearsals for debut story The Time Warrior , doubts over the pairing of Walker and Pertwee surfaced and the part was recast with Sladen. She stayed on Doctor Who for three-and-a-half seasons, alongside Pertwee as the Third Doctor and Tom Baker as
13622-432: The part of Sarah Jane to actress April Walker , who accepted the role and was duly contracted by the BBC. During rehearsals for The Time Warrior , it became clear to Jon Pertwee and Letts that the two leads had little rapport and were physically mis-matched (it has been claimed that Pertwee demanded the part be recast, because Walker was too tall for the role). Letts therefore released Walker from her contract (though she
13761-524: The particles including the defective ones. Infectivity assays measure the amount (concentration) of infective viruses in a sample of known volume. For host cells, plants or cultures of bacterial or animal cells are used. Laboratory animals such as mice have also been used particularly in veterinary virology. These are assays are either quantitative where the results are on a continuous scale or quantal, where an event either occurs or it does not. Quantitative assays give absolute values and quantal assays give
13900-399: The pilot episode, titled "A Girl's Best Friend", Sarah Jane receives the robot dog K9 Mark III ( John Leeson ) as a Christmas present from The Doctor. The pilot did not lead to a series, but the character reappeared in Doctor Who for the 1983 twentieth anniversary story " The Five Doctors ", in which she is transported to Gallifrey by Lord President Borusa ( Philip Latham ) to take part in
14039-505: The presence of Brian Miller, Sadie Miller , Tom Baker and Terrance Dicks . The BBC released an audio CD version of the book, read by fellow Doctor Who alumna Caroline John , on 1 December 2011. The foreword for the book was written by fellow Doctor Who actor David Tennant , who portrayed the Tenth Doctor . Sladen married actor Brian Miller on 8 June 1968 in Liverpool. Their daughter, Sadie Miller , appeared alongside Sladen in
14178-402: The present day, released in 2002 and 2006. Her husband, Brian Miller, appeared in the story Ghost Town . Her daughter Sadie appeared in the audios. Sladen also contributed interviews and DVD commentaries to many of the classic Doctor Who serials she co-starred in. Following the successful revival of Doctor Who in 2005, Sladen guest starred as Sarah Jane in " School Reunion ", an episode of
14317-552: The present day. Subsequently, she accompanies The Doctor ( Jon Pertwee ) on several journeys in the TARDIS, and she also assists the United Nations Intelligence Taskforce led by Brigadier Lethbridge-Stewart ( Nicholas Courtney ) on a number of occasions. After Pertwee's departure, Sladen remains following Season 11 finale Planet of the Spiders (1974), in which The Doctor regenerates for
14456-453: The rights, K9 only appears in two episodes of the first series. In the first series, Sarah Jane learns how to be a mother to Luke, the while strengthening her friendship with teenage neighbour Maria, the person Sarah Jane "trusts the most". Along with Luke and his friend Clyde Langer ( Daniel Anthony ) they defeat and repel various threats to the contemporary Earth. Amongst these threats, series one introduces The Trickster ( Paul Marc Davis ),
14595-546: The role. Sarah Jane first appears in the Third Doctor serial The Time Warrior (1973–74), where she has managed to infiltrate a top secret research facility by posing as her aunt, Lavinia Smith, a famous virologist . Introduced as an ardent feminist , Sarah Jane sneaks aboard the TARDIS and becomes embroiled in a battle against a militaristic alien Sontaran in the Middle Ages who is kidnapping scientists from
14734-407: The same sedimentation coefficient and are not removed by the procedure. In these cases a modification of centrifugation, called buoyant density centrifugation , is used. In this method the viruses recovered from differential centrifugation are centrifuged again at very high speed for several hours in dense solutions of sugars or salts that form a density gradient, from low to high, in the tube during
14873-599: The same continuity as one another. For example, the novels' mention of Sarah Jane as having been married is contradicted by the later Sarah Jane Smith audio play Dreamland , and the Sarah Jane Adventures episode "Invasion of the Bane". Sarah Jane Smith was consistently voted the most popular Doctor Who companion until the advent of the new series in 2005. Even in more recent times the character has continued to vie in popularity with Rose Tyler , Donna Noble , and Ace . Sladen felt that part of her popularity
15012-412: The series in "School Reunion", said she was his favourite companion from the classic series. Concerning the impact of the character, he said: "Because she was a comic companion; and I think that she, more than any other before her, redefined the role of the companion. And there are elements of Sarah Jane Smith that you can see in every companion afterward down to Amy . She changed the companion from being
15151-656: The series. The first 6 episodes were broadcast as originally intended in tribute to Sladen in October 2011. The programme won a Royal Television Society 2010 award for Best Children's Drama. Sladen also read original audio stories on CD for The Sarah Jane Adventures , which were released in November 2007: The Glittering Storm and The Thirteenth Stone . This was the first time that BBC Audiobooks had commissioned new content for exclusive release on audio. Further pairs of audio stories were released every year until 2010, all read again by Sladen. Sladen returned to Doctor Who in
15290-526: The show's fourth series in the concluding episodes " The Stolen Earth " and " Journey's End " and was credited in the title sequence of both episodes. Her final appearance in Doctor Who was a scene in the concluding part of " The End of Time ", Tennant's last episode as the Tenth Doctor. Just before her death, Sladen had also been interested in being involved in the Doctor Who Fourth Doctor Big Finish series. While Sladen
15429-402: The species of virus by plaque reduction assays . Viruses growing in cell cultures are used to measure their susceptibility to validated and novel antiviral drugs . Viruses are antigens that induce the production of antibodies and these antibodies can be used in laboratories to study viruses. Related viruses often react with each other's antibodies and some viruses can be named based on
15568-489: The spread of infectious virus, creating localized clusters (foci) of infected cells. Plates are subsequently probed with fluorescently labeled antibodies against a viral antigen, and fluorescence microscopy is used to count and quantify the number of foci. The FFA method typically yields results in less time than plaque or fifty-percent-tissue-culture-infective-dose (TCID 50 ) assays, but it can be more expensive in terms of required reagents and equipment. Assay completion time
15707-570: The spread of viral infections in communities ( epidemiology ). When purified viruses or viral components are needed for diagnostic tests or vaccines, cloning can be used instead of growing the viruses. At the start of the COVID-19 pandemic the availability of the severe acute respiratory syndrome coronavirus 2 RNA sequence enabled tests to be manufactured quickly. There are several proven methods for cloning viruses and their components. Small pieces of DNA called cloning vectors are often used and
15846-514: The television episodes have been novelised. Between seasons 13 and 14 , Sladen appeared as Sarah Jane, with Tom Baker as the Fourth Doctor, in the audio play The Pescatons , released on LP by The Decca Record Company Limited in 1976. She also appeared with Baker in "The Time Machine", episode three of the BBC Radio 4 series Exploration Earth broadcast on 4 October 1976. Also in 1976 she appeared as Sarah Jane alongside Tom Baker's Doctor in
15985-602: The therapeutic use of bacteriophages. By the end of the 19th century, viruses were defined in terms of their infectivity , their ability to pass filters, and their requirement for living hosts. Viruses had been grown only in plants and animals. In 1906 Ross Granville Harrison invented a method for growing tissue in lymph , and in 1913 E. Steinhardt, C. Israeli, and R.A. Lambert used this method to grow vaccinia virus in fragments of guinea pig corneal tissue. In 1928, H. B. Maitland and M. C. Maitland grew vaccinia virus in suspensions of minced hens' kidneys. Their method
16124-546: The third time . In season 12's consecutive 1975 serials The Sontaran Experiment , Genesis of the Daleks and Revenge of the Cybermen , Sarah and male companion Harry Sullivan ( Ian Marter ) face the series' three iconic recurring creatures, the Sontarans, the Daleks and the Cybermen . In Genesis Sarah is present at the creation of the Daleks and meets their creator, Davros ( Michael Wisher ). Sarah Jane departs in
16263-450: The tobacco mosaic virus and found it was mostly made of protein. A short time later, this virus was separated into protein and RNA parts. The tobacco mosaic virus was the first to be crystallised and its structure could, therefore, be elucidated in detail. The first X-ray diffraction pictures of the crystallised virus were obtained by Bernal and Fankuchen in 1941. Based on her X-ray crystallographic pictures, Rosalind Franklin discovered
16402-562: The type of nucleic acid forming their genomes. In 1966, the International Committee on Taxonomy of Viruses (ICTV) was formed. The system proposed by Lwoff, Horne and Tournier was initially not accepted by the ICTV because the small genome size of viruses and their high rate of mutation made it difficult to determine their ancestry beyond order. As such, the Baltimore classification system has come to be used to supplement
16541-759: The universe. On the Dalek ship Davros ( Julian Bleach ) recognises Sarah Jane from their encounter in the classic series' episode Genesis of the Daleks . In The Sarah Jane Adventures second series (2008), Maria moves away to America in The Last Sontaran , and Sarah Jane befriends new neighbour Rani Chandra ( Anjli Mohindra ) in The Day of the Clown ; the same episode features flashbacks to Sarah Jane's (Jessica Mogridge) childhood in her Aunt Lavinia's home. In The Temptation of Sarah Jane Smith , Sarah Jane saves
16680-446: The virus using a tagged monoclonal antibody . These are also used in agriculture, food and environmental sciences. Counting viruses (quantitation) has always had an important role in virology and has become central to the control of some infections of humans where the viral load is measured. There are two basic methods: those that count the fully infective virus particles, which are called infectivity assays, and those that count all
16819-487: The viruses are suspended in a solution of metal salts such as uranium acetate. The atoms of metal are opaque to electrons and the viruses are seen as suspended in a dark background of metal atoms. This technique has been in use since the 1950s. Many viruses were discovered using this technique and negative staining electron microscopy is still a valuable weapon in a virologist's arsenal. Traditional electron microscopy has disadvantages in that viruses are damaged by drying in
16958-467: The while continuing to work as a freelance investigative journalist. Sarah Jane is one of the Doctor's longest-serving companions, co-starring in 18 stories (80 episodes) with the third and fourth incarnations of the Doctor, on the programme from 1973 to 1976 (seasons 11 – 14). She and robotic dog K9 appear in the 1981 television pilot K-9 and Company . She returned in the 20th-anniversary Fifth Doctor story " The Five Doctors " (1983) and
17097-506: The years before PCR was invented immunofluorescence was used to quickly confirm viral infections. It is an infectivity assay that is virus species specific because antibodies are used. The antibodies are tagged with a dye that is luminescencent and when using an optical microscope with a modified light source, infected cells glow in the dark. PCR is a mainstay method for detecting viruses in all species including plants and animals. It works by detecting traces of virus specific RNA or DNA. It
17236-792: Was a primary school contemporary of future politician Edwina Currie , appearing in at least one school production with her. She went on to secondary school and attended Aigburth Vale High School for Girls . Sladen attended the Elliott-Clarke Drama School. In 1965, she made her first film appearance in Ferry Cross the Mersey as an uncredited extra. Sladen then joined the Hillbark Players, for their open-air production of Much Ado About Nothing , playing Hero. After two years at drama school, Sladen began work at
17375-607: Was at the British Film Institute on 12 October 2010, where there was a special showing of The Death of the Doctor , followed by a Q&A session. Her last public appearance was at the EA British Academy Children's Awards on 28 November 2010. Elisabeth Sladen: The Autobiography was released posthumously on 7 November 2011, by Aurum Press Ltd. The book was launched at 'The Doctor Who Experience', Kensington Olympia on 26 November 2011, in
17514-565: Was at the time." Elisabeth Sladen Elisabeth Clara Heath-Sladen (1 February 1946 – 19 April 2011) was an English actress. She became best known as Sarah Jane Smith in the British television series Doctor Who , appearing as a regular cast member from 1973 to 1976, alongside both Jon Pertwee and Tom Baker , and reprising the role many times in subsequent decades, both on Doctor Who and its spin-offs, K-9 and Company (1981) and The Sarah Jane Adventures (2007–2011). Sladen
17653-704: Was born 1 February 1946 in Liverpool , England. Sladen was the only child of Tom Sladen (1900–1994), who fought in the First World War and served in the Home Guard during the Second World War , and Gladys (1902–1978) (née Trainer). She developed an interest in performing at an early age, beginning dance lessons when she was five, and dancing in one production with the Royal Ballet . She
17792-595: Was first described in 1970 by Temin and David Baltimore independently. In 1983 Luc Montagnier 's team at the Pasteur Institute in France, first isolated the retrovirus now called HIV. In 1989 Michael Houghton 's team at Chiron Corporation discovered hepatitis C . There are several approaches to detecting viruses and these include the detection of virus particles (virions) or their antigens or nucleic acids and infectivity assays. Viruses were seen for
17931-525: Was her last on-screen appearance as Sarah Jane Smith before 2006. Sladen played Sarah Jane in several audio plays . Two of them were produced for BBC Radio , The Paradise of Death ( Radio 5 , 1993), and The Ghosts of N-Space ( Radio 2 , 1996), together with Jon Pertwee and Nicholas Courtney . In 1997, Sladen won Hall of Fame Actress in Cult TV Awards. Big Finish Productions produced two series of Sarah Jane Smith audio adventures set in
18070-502: Was in Doctor Who , she attended numerous public events to publicise the programme. Following her departure, she largely stopped attending related events as she felt it could be seen as bad manners to the new cast. After her initial run in Doctor Who ended in 1976, she returned to Liverpool with her husband and performed in a series of plays. This included a two-hander with Miller in Mooney and his Caravans . Subsequent appearances include
18209-454: Was in a two-part story of Z-Cars . These two episodes of Z-Cars have since been wiped and are listed as missing episodes by the BBC 's archive library. She then appeared as a terrorist in an episode of Doomwatch , followed by guest roles in further episodes of Z-Cars , Public Eye , Some Mothers Do 'Ave 'Em and Special Branch . In 1973, Doctor Who actress Katy Manning , who
18348-439: Was interested in ballet and theatre from childhood, and began to appear on stage in the mid-1960s, although she was more often a stage manager at this time. She moved to London in 1970 and won several television roles, with her acting in the police drama Z-Cars leading to her being recommended for the role in Doctor Who . After leaving the series, she had other roles on both television and radio before semi-retiring to bring up
18487-413: Was made of particles, he called it a contagium vivum fluidum (soluble living germ) and reintroduced the word virus . Beijerinck maintained that viruses were liquid in nature, a theory later discredited by Wendell Stanley , who proved they were particulate. In the same year, Friedrich Loeffler and Paul Frosch passed the first animal virus, aphthovirus (the agent of foot-and-mouth disease ), through
18626-554: Was not widely adopted until the 1950s when poliovirus was grown on a large scale for vaccine production. Another breakthrough came in 1931 when the American pathologist Ernest William Goodpasture and Alice Miles Woodruff grew influenza and several other viruses in fertilised chicken eggs. In 1949, John Franklin Enders , Thomas Weller , and Frederick Robbins grew poliovirus in cultured cells from aborted human embryonic tissue,
18765-491: Was playing the Third Doctor 's assistant Jo Grant opposite Jon Pertwee , was leaving the series; Z-Cars producer Ron Craddock gave Sladen an enthusiastic recommendation to Doctor Who producer Barry Letts . Sladen arrived at the audition not knowing it was for the new companion role, and was amazed at Letts's thoroughness. She was introduced to Pertwee, whom she found intimidating at the time. As she chatted with Letts and Pertwee, each time she turned to look at one of them
18904-561: Was still paid in full for season 11). Although committed to not talking about the issue in her release agreement, Walker began to discuss the circumstances surrounding her casting decades later. After giving some written interviews to fanzines, in May 2020 Walker gave an on screen interview to 'Time Space Visualiser' giving much further detail about the circumstances, including revealing later work alongside Pertwee. Walker admitted that although she understood Pertwee's thinking, she told him she would never forgive him for what he had done. Letts began
19043-710: Was such a good assistant stage manager that she did not get many acting roles, a problem that was solved when she accidentally made a mistake on one occasion. An earlier interview indicated that she deliberately made mistakes on several occasions. As a result, she began to get on-stage roles again. She eventually moved into weekly repertory work, travelling to various locations in Britain. Sladen and Miller moved to Manchester , in 1966, spending three years there. They married on 8 June 1968. She appeared in numerous roles, most notably as Desdemona in Othello , her first appearance as
19182-488: Was thought that all infectious agents could be retained by filters and grown on a nutrient medium—this was part of the germ theory of disease . In 1898, the Dutch microbiologist Martinus Beijerinck repeated the experiments and became convinced that the filtered solution contained a new form of infectious agent. He observed that the agent multiplied only in cells that were dividing, but as his experiments did not show that it
19321-502: Was working alongside Pertwee and Baker , who were popular Doctors. Daniel Martin of The Guardian named her the best companion in 2007, writing that her "jolly-hockey-sticks good nature" made her so beloved. The Daily Telegraph 's Gavin Fuller also ranked Sarah Jane number one, praising Sladen's portrayal and saying that she displayed "great determination and bravery". In 2012, Toby Whithouse , who wrote Sarah Jane's return to
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