The Characteristics of Retroviruses

The Characteristics of Retroviruses Retroviruses have various characteristics that make them unique as gene delivery vehicles. Their life cycle includes an integrated state in the DNA of the host chromosome. Retroviruses are the only animal viruses that integrate into the host cells genome during the normal growth cycle. They use an integrase that acts in a site-specific manner to join the ends of the viral cDNA to target sequences in host cell DNA. The linear ds cDNA made in the cytoplasm is transported to the nucleus where it is also found as circles and as integrated DNA. Two forms of circular DNA are generally found: one having a single Long Terminal Repeat (LTR) and one having two LTRs. It is now thought that the original integrated proviruses were linear molecules with two LTRs. The retroviral promoter can direct high-level, efficient expression of genes encoded within the viral capsid of its genome using chromatin. The retroviral genomes can accommodate changes to its configuration. Retroviruses offer gene therapy researchers aid for delivering genes to target cells at high efficiency that allows for long-term, stable expression of introduced genetic elements The retroviral life cycle begins in the nucleus of an infected cell. At the beginning of the life cycle the retroviral genome is a DNA element integrated into and covalently attached to the DNA of the host cell. Full-length genomic mRNA is made starting at the beginning of the repeat at the 5 LTR (Long Terminal Repeat). The free particle can infect new cells by binding to a cell surface receptor. The specificity of the virus-cell interaction is determined most commonly by the envelope proteins of the retrovirus. Infection leads to injection of the virus nucleoprotein core (consisting of many gag-derived proteins, full-length genomic RNA, and the reverse transcriptase protein). Once inside the cell, the nucleoprotein complex accesses intracellular DNA nucleotide triphosphate pools, where the reverse transcriptase protein initiates and creation of a double-stranded DNA copy of the genome of the virus is prepared for integration into the host cell chromosome. When reverse transcription is completed, the viral enzyme integrase looks for an appropriate storage place for the DNA, which the integrase clips the host DNA to and binds the double-stranded DNA into the host DNA. The virus is the able to initiate a new round of replication again. 3 major proteins encoded in a retroviral genome Gag is a polyprotein and is an acronym for Group Antigens (ag). Pol is the reverse transcriptase. Env is the envelope protein. The group antigens form the viral core structure and are the major proteins which comprise the nucleoprotein core particles. Reverse transcriptase is the essential enzyme that carries out the reverse transcription process that take the RNA genome to a double-stranded DNA preintegrate form. General transcription and proteins are encoded from spliced mRNA of retroviruses. Transcription proceeds through the genome and mRNA is polyadenylated and processed using signals in transcribed regions from the 3 LTR at the end of the transcribed R (repeat). The full-length message can be spliced to lead to production of envelope proteins (or other proteins depending upon retroviral class). Unspliced full-length mRNA can give rise to gag-pol proteins. Gag and Pol are made as either Gag protein or a Gag-Pol precursor. Translated proteins assemble a retroviral particle at the cell surface. Full-length genomic unspliced mRNA is bound by gag-derived proteins and incorporated into the budding particle. Virion structures In retroviruses particle shapes can be divided into distinct categories: A-type particles are immature intracellular forms derived from endogenous retrovirus-like elements and the immature form of MMTV. B-type particles correspond to the extracellular form of MMTV and are characterised by prominent surface protein spikes and a dense asentric nucleocapsid. C-type particles form at the surface of the cell at the site of budding. Lentiviruses bud like C type particles but have a distinctive blunted cone shaped core. D-type particles are the MMPV related viruses of sub-human primates, and differ from B-type particles by a lack of surface spikes. The gag (group specific antigen) gene encodes the viral matrix, capsid and nucleoproteins The protease encodes a product that cleaves the gag polyprotein precursor. It can be encoded as part of Gag or a Gag-Pro-Pol polyprotein The major read-through product is derived from the pol gene which encodes the reverse transcriptase and an integrase which is involved in provirus integration. The envelope gene encodes the surface glycoprotein (SU) transmembrane (TM) polyprotein. Viral entry Retroviruses enter by at least two different manners, dependent upon the retroviral subclass. The viral envelope is critical in each case for recognising appropriate surface receptors to initiate viral fusion to the host target cells. The RNA genome in the free retrovirus is arranged as a diploid genome with identical sequences. The mRNA associates with a tRNA primer (pro, trp, or lys) that is bound by complementary base pairing to 18 base pairs to the U5 region. The integrated form (proviral) of all retroviruses contain transcription regulatory sequences primarily in Long Terminal Repeats (LTR). LTR sequences are derived from sequences unique to the 5 end of viral RNA (U5), from sequences unique to the 3 end of viral RNA (U3), and from sequences repeated at both ends of the viral RNA. The integrated provirus is larger than the viral genome but its complexity is the same because of duplication of U3 and U5 during synthesis. Replication of retroviruses is sensitive to the transcription inhibitors Actinomycin D, alpha-amanitin nucleoside and analogues like 5-bromodioxyuridine and cytosine arabinoside. 5 bromodioxyuridine and cytosine arabinoside are thought to inhibit DNA replication.

Movie Yasmin Essay

‘Yasmin is remarkable as a film for its cinematic economy: not a scene, shot or speech is wasted. ’ Explore some elements of the film in relation to this statement. The movie Yasmin, released in 2004 and written by the highly acclaimed writer of The Full Monty, Simon Beaufoy, is an impressive drama about what it means to be an Asian-looking Muslim in Britain of the 21st Century. The story is about the young and vivid Yasmin, a woman who tries to â€Å"succeed, by the skin of her teeth,†[1] in the two worlds she grew up in.On the one hand there is her life at home with her believing father and rebellious little brother, for whom she has to mark â€Å"time as a dutiful Muslim wife until her arranged marriage can be terminated. â€Å"[2] On the other hand there is her life outside this domesticity, where she is â€Å"like a fugitive, maintaining a double life as she changes into Western clothes, wins employee of month award at work and goes to the pub with colleag ues. â€Å"[3] One of the main topics of the movie is the difficult tension between being a religious and respectful woman and integrating into the Western society.Another important theme in the movie is the impact that the terror attacks in September 2001 had on the British Asian community in Britain. Yasmin’s story therefore deals with a wide range of themes such as discrimination, guilt, and the progress of searching for one’s own identity. It is especially â€Å"remarkable as a film for its cinematic economy (since) not a scene, shot or speech is wasted. † There are no fill-ups in this movie, everything has a meaning. This essay will explore some carefully chosen scenes of the movie concerning its sometimes hidden or masked intention and meaning.It will therefore especially concentrate on the beginning scene, which is regarded as being â€Å"the strongest part of the film†[4]. A closer look at the opening of the film is worth it since every well comp osed novel or film is creating a deliberate relationship between the beginning and the rest of the movie. It will be examined in the following, that additionally in the case of Yasmin the directors develop a consistency, a pattern of the main themes of the film, in the beginning.Everything is already there in the very first three and a half minutes; things shown in the opening reappear later in the movie; conflicts the film deals with can already be assumed in moves, placements, and pictures. It will be proven that, if taken into account every detail, every shot of the scene, the viewer will already be able to see the whole film in miniature in the beginning. The essay will therefore also have a closer look on what is shown in the opening scene and will then search for coherences and connections throughout the rest of the movie.It will hereby not go through the scene chronologically but will pick up separate shots of it and put them together in categories; although it will start wit h the first shot to which the viewer is introduced in the movie. When Khalid, Yasmin? s father, lopes over a typical grey English street followed by Nazir, Yasmin? s brother, a few steps behind him, Nazir? s bearing strikes the viewer immediately: the way he creeps a few steps behind his father with the hands in his pockets expresses discouragement, maybe even irritation.He seems to be unhappy with the situation, possibly because it? s too early in the morning, since gentle beams of sunrise just touch the wall behind them; possibly because he dislikes the purpose of their walk. His father, however, hastens to raise this purpose: in his hurry he turns around to see where his son has got to. It becomes clear that it is the father who controls the situation— that he is the leader whom the son has to follow. So apart from the obvious, the authority person walking in front might tell the viewer something about the relation between father and son.One could even go further and sugge st it might also tell something about their attitude towards life, about their religion, about the way the head of the family is treated in the Islam faith. The scene therefore implicates the parental respect of which is set value in this family. How important this topic is to Yasmin? s father Khalid becomes more and more clear during the course of the movie: he repeatedly calls for respect towards the parental authority over his children. When Yasmin is complaining about her husband and gives him humiliating names, Khalid reprehends her immediately and stresses his will with a slight slap.He even repudiates Yasmin when she dares to apply for a divorce against his will. So the viewer already gets in this very first scene, in the very first seconds, an initial impression of what domestic life in this family is about: about respect and family ties. The two move on and finally arrive at the mosque, which is gated by a metallic blind. After abandoning their shoes, Nazir and Khalid enter the interior of the mosque; and in doing so they pace over a formidable carpet in a remarkable red. It s admirable how strikingly this little scene influences the movie? s atmosphere: after the grey and dusty outside of the mosque with its bleak stone-walls and metallic blinds covering the entrance, the viewer now gets an impression of the inside; the colourful, bright, shining red carpet. The jump is a quiet astonishing little moment: the greyness outside opposes the bright shining colour of the huge carpet these seemingly little people are crossing (amplified by the way the scene is shot: with bird? eye view). Inside the mosque the viewer gets a sense of richness, a glimpse on the whole tradition, an idea about the Islam faith. The scene is not just remarkable because of its visual orchestration, but also in introducing the viewer to this huge and rich religion and the way it sees the world. Later in the beginning scene there is a shot that shows the grey and grim wall of a Yorks hire stone house in the front, again contrasted by the beautiful outlines of the colourful mosque in the background.The two absolutely different styles of architecture standing next to each other implicate a huge imagery: the mosque as a symbol for the tradition and a stonewall which symbolizes the here and now, indicates how the life of the Muslim people in Great Britain stands side by side with the traditional life of the British natives. This deliberate expression of a coexistence of the two traditions is an expression of crossing cultures at its best in this movie, and at this point of the movie it also stands for a successful integration of the Muslim tradition into the British society.This impression is furthermore stressed during the course of the beginning scene: the mosque is using modern techniques; it is using the loudspeaker, the microphone, so a lot of quite modern technology. Satellites are shown. Here the movie is not only supposing the ageing culture of Islam against the modern British culture of science and technology but goes further: it brings it together. There is an interchange going on here through what the viewer can hear (the singing of Nazir) and what he can see (the loudspeakers and satellites).By bringing these aspects together at the same time the fusion becomes immediately clear to the viewer. In another shot of the beginning scene the viewer observes the vivid life of the Muslim community that is taking place in the streets of the town. Even though one quickly might suggest that this shot might be just a fill-up it, in fact, goes further: the viewer here gets an impression of what the life in this Muslim community is like. The reason for that is that later in the film, after the 11th of September 2001, the same streets are depicted deserted, isolated, dead.Whereas the beginning scene expresses the successful integration of the Muslim tradition into the British society, the contrasting scene in the middle of the movie now stands fo r the failure of this coexistence, for the loss of community. The remarkable contrast of this two scenes is to â€Å"illuminate Muslims' increasing disenchantment with Western society†[5] after the terror attacks. So it now comes clear that nothing in the movie is there without reason: showing a typical East-Asian community in a British town is not a fill-in but is a part of the whole effort of later showing a community being disrupted. Nothing in the movie is wasted.One of the most impressing returning scenes of the movie is Nazir singing in front of the microphone. Also this theme is introduced in the beginning scene: after watching the film the first time, the peaceful scene in the beginning immediately reminds the viewer to the very last scene in the movie, when Khalid, the father is putting in a tape into the recorder as an ersatz for the son. This final scene has a huge impact on the viewer since one here really realizes that Nazir has gone off and will not come back. I t is therefore a really tragic little moment: it is emotional even though there is no actor playing the emotion.What is on the first glance less striking but not less important is that the image of the son singing comes back three times during the course of the movie; in the beginning, in the middle, and in the end. It runs through the film like a red thread: in the beginning it is, as said, introducing not only to the family? s religion but also to the family background itself. In the scene in the middle of the movie Nazir, before he starts, coughs as if he smoked too much. Since the viewer knows that he started â€Å"indulg(ing) in petty drug dealing and consorting with local girls†[6], it seems as if he became corrupted by what he is doing with his life.His coughing therefore is again not without meaning but stands for Nazir? s life becoming more difficult to handle. The returning scene is a marker in the film and each time it means something different: in the beginning it is quite straight forward, in the middle it appears as a comment for what happened to Nazir and his life, and in the end it is tragic since he is gone and will never come back. So as a major thread throughout the movie the scene with the singing Nazir displays the different states the movie and its protagonists are currently in. A similar red thread s the theme of dressing and clothes that recurs throughout the film and, again, the theme is already introduced in the opening. By watching Yasmin changing her clothes hidden by one of the typical grey stone-walls one gets an impression of this girl transforming herself into another person. Yasmin makes an enormous effort of putting herself into the trousers, since they are really too tight. She tries hard to fit herself in, she even has to jump up and down. The connection is easy to make: this movie is about someone who tries to fit in with two different worlds, tries to force herself in.So here the choice of incredibly tight trousers simply indicate what Yasmin really wants: she wants to make herself fit. If something returns deliberately, a number of times, during the film it becomes a symbolic act: when Yasmin for example dresses up to revolt against her father later in the movie, it symbolizes Yasmin? s wish to break out, to be able to be herself. In the end of the film she switches to traditional Muslim clothes, since she is at this point of the movie staying in the side of the traditional. Here the clothes express how a religious thought became fixed and hardened. Dressing here becomes a signifier for her state of mind.Since it returns later in the movie several times it always tells the viewer something when it comes to clothes. So by following how the dressing in this movie changes throughout the plot one gets a neat impression of how the state of Yasmin’s mind changes with it. The clothes are never chosen without reason in Yasmin, there is an intention in every piece the actors wear. Even though i t is just a little detail it strikes the viewer and is therefore very well-thought. So after Yasmin changed her clothes she turns over to her car and plays around with it: she locks and unlocks it with her remote control several times.This car is, as Yasmin later in the movie declares, not a ? t. p. car`, a ? typical paki-car`, but a sporty, feminine little cabriolet in an outstanding red. With this car, she wants to separate herself from those typical Pakistani people, and, even further, wants to declare her independence: â€Å"it gives her a life away from her husband and her home†[7]. By buying this car she is able to show herself and everybody else that she is different, what makes it an act of almost deliberate despair. But on the other hand, by playing around with the car, she expresses her excitement.She does it simply because she can. This gives the viewer a sense of how she is playing with things she owns, how she creates the parts of the world around her she can con trol in the way she likes it. The motif also returns later in the movie, after 9/11: Yasmin gets in the car and there is a news report on the radio about the terror-attacks. Yasmin? s reaction is as playfully as in the beginning of the movie: she just puts a CD in, and listens to the music. She does simply not want to think about, does not want to care. The viewer gets an impression of the ambiguity of Yasmin? life, of how difficult it must be to live in two different worlds, to create her life successfully around the different expectations the people she deals with have of her. The last shot of the opening scene in the movie depicts this challenge in a deliberate way: it shows the long, small, winding road Yasmin has to take day by day to drive to work and back. This road is the connection of the two worlds she lives in; it is a connecting thread between not only two different locations but two different worlds. Yasmin is having this journey – this transformation, this strug gle – every day.By driving over this street she is migrating from one world to another and she has to transform herself before she is accomplished with the migration, since she changes her identity day by day. Furthermore the road is connecting the two different worlds as well as dividing them. That becomes clear through the visual impact of this shot: the road is crossing the whole screen and Yasmin and her little car have to follow its way through the landscape; it deliberately makes the viewer ask: how long will it take her? And how long will she stand this?The struggle of â€Å"balancing two separate worlds in quest to please (a) conservative family, without sacrificing the obvious advantages of the Western environment†[8] is depicted as lovely and rich in detail in the movie Yasmin. It is â€Å"the beautifully realised opening, entirely without dialogue for a good few minutes, (that) is the strongest part of the film†[9] as it, as shown, already gives the w hole of the movie, its main conflicts, themes and topics in miniature. Although this is a primarily visual scene, dialogue, if used in the movie, is very effectively— â€Å"Not a scene, shot or speech is wasted. But the dialogue is used economically and not in the opening: it is a visual opening; in general, Yasmin is a visual movie. Every scene, every act, every piece of clothing has a meaning. As the director of the movie, Kenny Glenaan himself, says: â€Å"obviously the beauty is what you can do within the frame and some people are amazing at doing that. â€Å"[10] Bibliography Dilks, Richard, Yasmin, in Close-Up Film, 2003, http://www. close-upfilm. com/reviews/y/yasmin. htm Docherty, Alan, Yasmin – Kenny Glenaan, in Culture Wars, 2001, http://www. culturewars. org. uk/2004-02/yasmin. tm Glenaan, Kenny, in a BBC Interview, last updated in September 2004, http://www. bbc. co. uk/films/festivals/edinburgh/yasmin. shtml Jennigs, Tom, Tom Jennings’ essay on c inema representations of European Asians & Muslims, 2005, http://libcom. org/library/ae-fond-kiss-dir-ken-loach-yasmin-dir-kenny-glenaan-head-dir-fatih-akin-film-review The Hindu Magazine, Being Asian, Muslim and British, Online edition of India's National Newspaper, 2003, http://www. hindu. com/mag/2004/11/14/stories/2004111400270200. htm ——————————— [ 1 ].Docherty, Alan, Yasmin – Kenny Glenaan, in Culture Wars, 2011, http://www. culturewars. org. uk/2004-02/yasmin. htm [ 2 ]. Docherty, Alan, Yasmin – Kenny Glenaan, in Culture Wars, 2011, http://www. culturewars. org. uk/2004-02/yasmin. htm [ 3 ]. Docherty, Alan, Yasmin – Kenny Glenaan, in Culture Wars, 2011, http://www. culturewars. org. uk/2004-02/yasmin. htm [ 4 ]. Dilks, Richard, Yasmin, in Close-Up Film, 2003, http://www. close-upfilm. com/reviews/y/yasmin. htm [ 5 ]. Docherty, Alan, Yasmin – Kenny Glenaan, in Culture Wars, 2011, http://www. culturewars. org. uk/2004-02/yasmin. tm [ 6 ]. Jennigs, Tom, Tom Jennings’ essay on cinema representations of European Asians & Muslims, 2005, http://libcom. org/library/ae-fond-kiss-dir-ken-loach-yasmin-dir-kenny-glenaan-head-dir-fatih-akin-film-review [ 7 ]. Dilks, Richard, Yasmin, in Close-Up Film, 2003, http://www. close-upfilm. com/reviews/y/yasmin. htm [ 8 ]. The Hindu Magazine, Being Asian, Muslim and British, Online edition of India's National Newspaper, 2003, http://www. hindu. com/mag/2004/11/14/stories/2004111400270200. htm [ 9 ]. Dilks, Richard, Yasmin, in Close-Up Film, 2003,

Jonathan Livingstone Seagull Essay

After reading on Jonathan Livingstone seagull, write down reflective value and believe about the meaning and purpose of life. Jonathan Livingston Seagull is about a very independent bird, who dared to question what was being taught and told to him by the elders. He didn’t just want to spend his days searching for food and hanging out doing what was expected of him. He was different, and dared to dream. He spent his days learning to fly faster and better than any other gull in the flock. He learned from all of his searching and trying that he could do anything, if he wanted it badly enough and just went for it, even to the point of becoming an outcast. At one point in time, in so learning and perfecting his craft, he crash landed and died, going onto a higher lever of his awareness, to learn more lessons from his guide, Fletcher. He continues through the story, becoming more and more proficient in his endeavours and in turn becomes a teacher/guide to others, becoming a kind and loving soul along the way. Jonathan Livingston Seagull is a bird who wants nothing more than to fly. Raised in a group of gulls that saw flying as only a means to an end, Jonathan challenged their way of life by believing that flying could be about more than transportation or getting food†¦ it could be about joy and happiness and freedom. When told he was irresponsible for trying exceed his expectations Jonathan replied: â€Å"Who is more responsible than a gull who finds and follows a meaning, a higher purpose for life? For a thousand years we have scrabbled after fish heads — and now we have a reason to live — to learn, to discover, to be free! † An outcast from his flock, Jonathan took his exile with a grain of salt, finding joy in his love for flight and his constant desperate desire to grow and to learn. He pushes himself to the breaking point and is never satisfied enough with his knowledge and never tires of the quest to obtain more. Bach gives us a character that stands alone with his ideas and beliefs and is rewarded for his patience and courage. The second half of the book shows Jonathan learning so much that he transcends his earthly form into a higher plane of being. Here, Jonathan is met with other gulls who like him, strive for excellence and do not see flying as a means to an end, but simply love to fly for the sake of loving it. This part begins to reflect a bit of the Buddhist mindset about heaven and a universal knowledge which can seem a bit confusing at first. Jonathan finally returns to his flock on Earth to try for better or worse to show that there is more to life than what they are striving for. This is a fable about the importance of making the most of our lives, even if our goals run contrary to the norms of our flock, tribe or neighbourhood. Through the metaphor of flight,Jonathan’s story shows us that, if we follow our dreams, we too can soar. Amazing inspiring story of seagulls. It tells us nothing is impossible in this world. You just have to have the desire to achieve it.

Analysis Of Mark Edmundson s New York Times Piece,...

Case Study #1: Bennington College Mark Edmundson’s New York Times piece, Bennington Means Business, provides an alumnus’ narration of the overhaul of Bennington College in 1994. The piece also provides an ideal model of an organization in change, which elucidates the undercurrents of educational leadership theory that commonly materialize in more nuanced and less pronounced ways. First, attention will be paid to the symbolism of Bennington College, particularly as chronicled by Edmundson. Then, the natural selection view of organizations will be discussed in relation to Bennington’s decline. The intercession of Liz Coleman highlights themes of the political frame, organizational structure, and leadership styles to be analyzed further and†¦show more content†¦The challenge to an institution or leader operating in the symbolic frame, though, is to create meaning, and this is where Bennington College has struggled. Edmundson (1994) admits that â€Å"it is mainly†¦for trying to sustain [its ideals] that the college has come to grief.† Even Liz Coleman, the president of Bennington College (with whom Edmundson often seems to disagree), acknowledges the importance of symbolism to her institution. â€Å"‘Bennington,’ Coleman said, ‘has got to do something that no one else is doing,’† or, in other words, Bennington needs an image, it needs direction, and it needs symbolism (Edmundson, 1994). Although different individuals have different ideas about what that â€Å"something† ought to be, there seems to be consensus around the idea symbols lend value, foster an image, and bolster organizational mission. In short, symbols matter to institutions. Symbols, however, do not always suffice to keep organizations afloat. In 1993, Bennington College’s Board of Trustees began an organizational remodeling referred to as the Symposium Process. The energetic, artistic, and creative student body that had symbolized the Bennington culture for so long was in decline. According to Liz Coleman, Bennington â€Å"‘became mediocre over time,’† especially as other colleges and universities adopted the symbols that had previously brought Bennington such success (Edmundson, 1994). Edmundson (1994) makes clear, however, that it is not just