Academic literature on the topic 'Silent bgl operon'

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Journal articles on the topic "Silent bgl operon"

1

Madan, Ranjna, Roberto Kolter, and S. Mahadevan. "Mutations That Activate the Silent bgl Operon of Escherichia coli Confer a Growth Advantage in Stationary Phase." Journal of Bacteriology 187, no. 23 (December 1, 2005): 7912–17. http://dx.doi.org/10.1128/jb.187.23.7912-7917.2005.

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ABSTRACT Wild-type strains of Escherichia coli are unable to utilize aromatic β-glucosides such as arbutin and salicin because the major genetic system that encodes the functions for their catabolism, the bgl operon, is silent and uninducible. We show that strains that carry an activated bgl operon exhibit a growth advantage over the wild type in stationary phase in the presence of the rpoS819 allele that causes attenuated rpoS regulon expression. Our results indicate a possible evolutionary advantage in retaining the silent bgl operon by wild-type bacteria.
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Giel, Maryann, Martine Desnoyer, and Jane Lopilato. "A Mutation in a New Gene, bglJ Activates the bgl Operon in Escherichia coli K-12." Genetics 143, no. 2 (June 1, 1996): 627–35. http://dx.doi.org/10.1093/genetics/143.2.627.

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Abstract A new mutation, bglJ4, has been characterized that results in the expression of the silent bgl operon. The bgl operon encodes proteins necessary for the transport and utilization of the aromatic β-glucosides arbutin and salicin. A variety of mutations activate the operon and result in a Bgl+ phenotype. Activating mutations are located upstream of the bgl promoter and in genes located elsewhere on the chromosome. Mutations outside of the bgl operon occur in the genes encoding DNA gyrase and in the gene encoding the nucleoid associated protein H-NS. The mutation described here, bglJ4, has been mapped to a new locus at min 99 on the Escherichia coli K-12 genetic map. The putative protein encoded by the bgygene has homolgy to a family of transcriptional activators. Evidence is presented that increased expression of the bglJ product is needed for activation of the bgl operon.
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Ueguchi, Chiharu, Tomoko Ohta, Chiharu Seto, Tomomi Suzuki, and Takeshi Mizuno. "The leuO Gene Product Has a Latent Ability To Relieve bgl Silencing inEscherichia coli." Journal of Bacteriology 180, no. 1 (January 1, 1998): 190–93. http://dx.doi.org/10.1128/jb.180.1.190-193.1998.

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ABSTRACT The Escherichia coli bgl operon is of interest, since its expression is silent (phenotypically Bgl−), at least under standard laboratory conditions. Here we attempted to identify atrans-acting factor(s) that is presumably relevant to the regulation of bgl by a random insertion mutagenesis with mini-Tn10. These collected mutations, conferring the phenotype of Bgl+, were localized in three loci on the genetic map, two of which appeared to be hns andbglJ, which were previously implicated as the factors affecting the Bgl phenotype. The other locus at 1 to 2 min on the genetic map appeared to be a new one. In this case, the insertion mutation was found to be just in front of the leuO gene encoding a putative LysR-like DNA-binding protein. Genetic analyses revealed that overproduction of LeuO in the wild-type cells causes the phenotype of Bgl+. A leuO deletion mutant was also characterized in terms of expression of bgl. From these results, the possible function of LeuO in bglexpression will be discussed from an evolutionary and/or ecological point of view.
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Moorthy, Sudha, and S. Mahadevan. "Differential Spectrum of Mutations That Activate the Escherichia coli bgl Operon in an rpoS Genetic Background." Journal of Bacteriology 184, no. 14 (July 15, 2002): 4033–38. http://dx.doi.org/10.1128/jb.184.14.4033-4038.2002.

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ABSTRACT The bgl promoter is silent in wild-type Escherichia coli under standard laboratory conditions, and as a result, cells exhibit a β-glucoside-negative (Bgl−) phenotype. Silencing is brought about by negative elements that flank the promoter and include DNA structural elements and sequences that interact with the nucleoid-associated protein H-NS. Mutations that confer a Bgl+ phenotype arise spontaneously at a detectable frequency. Transposition of DNA insertion elements within the regulatory locus, bglR, constitutes the major class of activating mutations identified in laboratory cultures. The rpoS-encoded σS, the stationary-phase sigma factor, is involved in both physiological as well as genetic changes that occur in the cell under stationary-state conditions. In an attempt to see if the rpoS status of the cell influences the nature of the mutations that activate the bgl promoter, we analyzed spontaneously arising Bgl+ mutants in rpoS+ and rpoS genetic backgrounds. We show that the spectrum of activating mutations in rpoS cells is different from that in rpoS+ cells. Unlike rpoS+ cells, where insertions in bglR are the predominant activating mutations, mutations in hns make up the majority in rpoS cells. The physiological significance of these differences is discussed in the context of survival of natural populations of E. coli.
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Ohta, Tomoko, Chiharu Ueguchi, and Takeshi Mizuno. "rpoS Function Is Essential forbgl Silencing Caused by C-Terminally Truncated H-NS inEscherichia coli." Journal of Bacteriology 181, no. 20 (October 15, 1999): 6278–83. http://dx.doi.org/10.1128/jb.181.20.6278-6283.1999.

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ABSTRACT From evolutionary and physiological viewpoints, theEscherichia coli bgl operon is intriguing because its expression is silent (Bgl− phenotype), at least under several laboratory conditions. H-NS, a nucleoid protein, is known as a DNA-binding protein involved in bgl silencing. However, we previously found that bgl expression is still silent in a certain subset of hns mutations, each of which results in a defect in its DNA-binding ability. Based on this fact, we proposed a model in which a postulated DNA-binding protein(s) has an adapter function by interacting with both the cis-acting element of the bgl promoter and the mutated H-NS. To identify such a presumed adapter molecule, we attempted to isolate mutants exhibiting the Bgl+ phenotype in the background of hns60, encoding the mutant H-NS protein lacking the DNA-binding domain by random insertion mutagenesis with the mini-Tn10camtransposon. These isolated mutations were mapped to five loci on the chromosome. Among these loci, three appeared to be leuO,hns, and bglJ, which were previously characterized, while the other two were novel. Genetic analysis revealed that the two insertions are within the rpoS gene and in front of the lrhA gene, respectively. The former encodes the stationary-phase-specific sigma factor, ςS, and the latter encodes a LysR-like DNA-binding protein. It was found that ςS is defective in both types of mutant cells. These results showed that the rpoS function is involved in the mechanism underlying bgl silencing, at least in thehns60 background used in this study. We also examined whether the H-NS homolog StpA has such an adapter function, as was previously proposed. Our results did not support the idea that StpA has an adapter function in the genetic background used.
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6

Bonner, Frances. "The Hard Question of Squishy Machines." M/C Journal 2, no. 6 (September 1, 1999). http://dx.doi.org/10.5204/mcj.1785.

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Among the sub-genres of science fiction, one of the most traditional and most machine-laden is space opera. The name is dismissive and was coined in parallel with the now little recognised 'horse opera' (for westerns) in the wake of the success of the term 'soap opera' (for romantic serials). Space operas were adventure sagas across the galaxies with space ships carrying intrepid crews on voyages of discovery, into glorious battles and terrifying encounters with aliens. The 'opera' part presumably refers to their seriality and overstated melodrama. At various times during the last fifty years space opera has seemed as doomed as the horse type, but sufficient examples were published to keep the sub-genre puttering along until new authors could invigorate it. This has now happened and I want in this brief note to see the change, through looking at one current writer's series to see what has been done, how it has been received and how observing the role of a particular novum (Darko Suvin's term for the imaginative invention that characterises sf) -- a machine in this case, of course -- illuminates what has happened. Because this begins with a consideration of sf history, I want to start with one of the key distinctions that has long operated in both popular and academic analysis of science fiction (though admittedly it has more currency now in the popular); that between hard and soft sf. Unsurprisingly, given how loaded those terms are, it is a gendered distinction. Hard sf is the boys' playground; technologically driven, its allegiances are to physics and engineering. From nano-widgets to space ships as big as planets, it loves machines. The boysiness of hard sf was sedimented in popular sf through the generic hegemony achieved by Hugo Gernsback in his US pulp magazine empire starting with Astounding in 1926. Space opera was the quintessential type of hard sf in the early years, though it came to be challenged if not displaced by colonisation narratives that concentrated on engineering. Soft sf, of necessity the girly stuff, has the squishy bits -- biology certainly, but also the social sciences. Both New Wave and feminist sf, the innovative sub-genres of sf in the 60s and 70s, used soft rather than hard tropes in their subsequently incorporated revisions of the genre. In the 80s, cyberpunk presented itself as the hard stuff, but this was pretty disingenuous (all that voodoo, those drugs, the excursions into various social sciences), not to mention, as Samuel Delany among others has pointed out, the way this could only be managed by denying its feminist foremothers. These days, the traces of space opera's pulp-laden past are there to be read in the way that the more serious American writers like Kim Stanley Robinson prefer sober space colonisation narratives while the truly innovative work (as well as the quality writing) is done outside the US, by a Scot -- Iain M. Banks. In addition to Banks's wondrous novels of the Culture, the revivified field includes more traditional series like Lois McMaster Bujold's Vorkosigan saga, David Weber's Honor Harrington sequence and Colin Greenland's tracing of the career of Tabitha Jute. It would not be possible to examine how Banks has remapped the field in a note such as this, but dealing with some of the more traditional examples can provide an interesting case study in the hardness of the sub-genre, as well as pointing to wider movements in the sf world. It is the latter that is evident in the way in which the male writers produce female lead and the female the male (by and large, Bujold does occasional female leads). Not that Weber makes any attempt to make Honor credible as a female, she's laughably improbable and only needs to be placed near Greenland's Tabitha Jute for the disparity to become evident. (I'm using this comparison not just for its power but also because it stops the suggestion that male writers can't produce decent female action heroes.) For the more detailled part of this I want to concentrate on Bujold's series in part to mull over why it might be that her books are dismissed as too soft and 'girly' to be good space opera. There is something of a problem in that I find the whole hard:soft distinction more than a bit juvenile and value it primarily for its power in understanding sf history. The moves to broaden the field beyond what it was so artificially limited to in early to mid-twentieth century America seem to me to be a move to a more integrated adulthood rather than the imposition of a line of squishy feminine referents to be denied or repelled. I don't see 'softness' as a negative quality (nor 'hardness' for that matter), but I am interested in why and how a space opera series with space ships, space weaponry, gadgets galore and large quantities of prime quality derring-do should be deemed soft. Bujold has written a long series of space operas set in an Earth-colonised far-future that centre on the deformed figure of Lord Miles Vorkosigan. A few other fictions are set in the same universe and link in various ways to the core texts. Not all are set on spaceships though the majority require their presence as significant features of the plot while others rely on such standards of space narrative as space stations, terra-forming and the hardware of space warfare. To dismiss Bujold's world as one where the hardness of space opera technology is subsumed in girliness, it is necessary to overlook not just great passages of certain texts, but to dismiss whole novels. The Vor Game for instance follows a long sequence at an arctic weather station which culminates in the necessary destruction of outdated toxic weaponry with an escapade across great reaches of space in a whole range of ships displaying, selling and eventually using all manner of wonderful weaponry climaxing in a battle for control of a wormhole nexus. The only woman of any narrative prominence is a evil mercenary leader ("face of an angel, mind of a rabid mongoose"). One would think that it all sounds rather a sitter as a hard piece of space opera fare written for a readership of boys of all ages. My description though so far fails to convey where it is that Bujold has updated the sub-genre. It could be that the problem lies in the same place as the updating -- in the nuancing of the character of the hero Miles Vorkosigan and the continuing delineation of the interweaving of his double life as mercenary Admiral and loyal Imperial lieutenant. Traditionally the space opera hero comes into the world if not fully formed, then at least ready for a coming-of-age tale. Bujold shows us the formation of the hero, ensuring that he remains located within his extended family. It could be that complaints come from those who would prefer their heroes not to have mothers. But then again it could be about the humour. Bujold doesn't see earnestness as desirable and writes a fantastical adventure romp. It seems to me that this is one core difference between her and fellow Baen writer David Weber. There is no predicting what a descriptive passage about technology will lead to in Bujold; it could be a novel way to win hand to hand combat or a comic sequence making a moral point about abuse of power. For Weber, a sequence of space ships and weaponry is sufficient in itself, being an opportunity to talk of model numbers and ballistic capabilities with all the narrative brio of Tom Clancy (i.e. none), but at least Clancy is usually talking about something that has an existence in the real world. When both the machine and the science it operates by are more than speculative, labouring the trainspotters'-guide-to-hyperspace-technology talk can only delight anoraks. Machines are ends in themselves for Weber, means to a narrative or characterological point in Bujold. As well as why the machine is mentioned, there is also the question of what kind of machines are favoured. Maybe over the whole sequence, Bujold pays more attention to biologically-based technologies; when she focusses on engineering it is more often as a means to a biological end (usually terraforming), though in Falling Free, the least closely linked of the novels, the biology which enables the creation of the 'quads' -- freefall workers with four arms rather than arms and legs -- is in the service of engineering advantage. The passion in her work, and despite the humour and invention, there is considerable ideologically driven passion, is reserved for her biologically based beliefs -- that physical difference should be no barrier to achievement. As is common in sf, race is incidental and not part of the argument (it is rare for any but black writers of sf to see race as a meaningful issue for the future), but sex and ability are primary. Thus Miles, whose bones were damaged while a foetus and who is short and hunched, Bel Thorne, the hermaphrodite, Taura, the genetically engineered 'perfect soldier' eight foot tall with claws and fangs, Mark, Miles's clone brother and many others who appear less frequently carry the story of difference that must not be allowed to make a difference. Where gender is concerned, the popular spread of feminism means that forceful statements of position are read as political, not as some more woolly bit of being 'nice to the afflicted'. Bujold's feminism may be old-fashioned liberal rather than radical or post-modern, but it doesn't operate by parachuting women in to narratively significant positions of power. You buy the book and you get the argument and with Cordelia, Miles's mother, inscribed as the figure of rationality, the bases are loaded. The machine around which the discourse of liberation is organised, Bujold's novum and the machine which is the focus of complaint, is the uterine replicator -- an artificial womb. In the Bujold universe this is the ultimate good machine. It was a replicator that enabled Miles to survive after teratogenic damage in utero; his first love and his mother both issued from them; and it seems like the key test of a man is his willingness or otherwise to have his wife reproduce in vitro. I suppose I can see why this offends those wedded to old-fashioned hard space opera. Traditionally, the machines that tell the men from the girls/boys/lesser beings are the ships and their weaponry, but here the machines that count replicate the uterus (ultimate squishiness) and so, far from delivering death, deliver babies. Furthermore, their entry into the narrative is almost always the cue for a disquisition on the inequities of the patriarchal society within which Bujold sets almost all her action. InMirror Dance Miles's clone brother Mark finally meets the senior Vorkosigans. He is taken to a court ball by his 'mother' who explains the dynamics of the evening in terms of the political agenda of the old men and the genetic one of the old women. The men imagine theirs is the only one but that's just an ego-serving self-delusion. ... The old men in government councils spend their lives arguing against or scheming to fund this or that piece of off-planet military hardware. Meanwhile the uterine replicator is creeping in past their guard. (296) In the most recent book,Komarr, the main female character is an abused wife with a young son and the fact that her husband required her to bear the child herself is presented as just one of the many abuses he subjects her to. When you read the various passages which discuss the uterine replicators across the books, it can be surprising to discover the insistence with which barbarity and male oppression are figured in the refusal to countenance the machine and good men are revealed by their regarding it as a valuable device. It seems almost to verge on the excessive (but then this is not how such ephemeral texts as popular space opera are read, and if one put together a collection of the passages of 'best bits of weapons admiration' that would look a bit strange too). One could, if so minded, easily dismiss the Vorkosigan adventures as a bit girly on the basis of their enjoyment of interpersonal relations, character development, or romance. If, though, one were willing to admit that only certain pieces of hardware had generically usable hardness, it might rather be possible to observe that the carping at the centrality of the wrong kind of machine identifies much more accurately what is really worrying about the whole popularity of the series -- that this machine is a Trojan Horse for the incorporation through hard technology of 'hard' feminist politics. References Bujold, Lois McMaster. Komarr. Earthlight, 1998. ---. Mirror Dance Riverdale: Baen, 1994. ---. The Vor Game. Riverdale: Baen, 1990. Delany, Samuel R. Silent Interviews: On Language, Race, Sex, Science Fiction and Some Comics. Hanover: Wesleyan UP, 1994. Suvin, Darko. Metamorphoses of Science Fiction. New Haven: Yale UP, 1979. Citation reference for this article MLA style: Frances Bonner. "The Hard Question of Squishy Machines." M/C: A Journal of Media and Culture 2.6 (1999). [your date of access] <http://www.uq.edu.au/mc/9909/bujold.php>. Chicago style: Frances Bonner, "The Hard Question of Squishy Machines," M/C: A Journal of Media and Culture 2, no. 6 (1999), <http://www.uq.edu.au/mc/9909/bujold.php> ([your date of access]). APA style: Frances Bonner. (1999) The hard question of squishy machines. M/C: A Journal of Media and Culture 2(6). <http://www.uq.edu.au/mc/9909/bujold.php> ([your date of access]).
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Pugsley, Peter. "At Home in Singaporean Sitcoms." M/C Journal 10, no. 4 (August 1, 2007). http://dx.doi.org/10.5204/mcj.2695.

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The use of the family home as a setting for television sitcoms (situation comedies) has long been recognised for its ability to provide audiences with an identifiable site of ontological security (much discussed by Giddens, Scannell, Saunders and others). From the beginnings of American sitcoms with such programs as Leave it to Beaver, and through the trail of The Brady Bunch, The Cosby Show, Roseanne, The Fresh Prince of Bel Air, and on to Home Improvement, That 70s Show and How I Met Your Mother, the US has led the way with screenwriters and producers capitalising on the value of using the suburban family dwelling as a fixed setting. The most obvious advantage is the use of an easily constructed and inexpensive set, most often on a TV studio soundstage requiring only a few rooms (living room, kitchen and bedroom are usually enough to set the scene), and a studio audience. In Singapore, sitcoms have had similar successes; portraying the lives of ‘ordinary people’ in their home settings. Some programs have achieved phenomenal success, including an unprecedented ten year run for Phua Chu Kang Pte Ltd from 1996-2007, closely followed by Under One Roof (1994-2000 and an encore season in 2002), and Living with Lydia (2001-2005). This article furthers Blunt and Dowling’s exploration of the “critical geography” of home, by providing a focused analysis of home-based sitcoms in the nation-state of Singapore. The use of the home tells us a lot. Roseanne’s cluttered family home represents a lived reality for working-class families throughout the Western world. In Friends, the seemingly wealthy ‘young’ people live in a fashionable apartment building, while Seinfeld’s apartment block is much less salubrious, indicating (in line with the character) the struggle of the humble comedian. Each of these examples tells us something about not just the characters, but quite often about class, race, and contemporary societies. In the Singaporean programs, the home in Under One Roof (hereafter UOR) represents the major form of housing in Singapore, and the program as a whole demonstrates the workability of Singaporean multiculturalism in a large apartment block. Phua Chu Kang Pte Ltd (PCK) demonstrates the entrepreneurial abilities of even under-educated Singaporeans, with its lead character, a building contractor, living in a large freestanding dwelling – generally reserved for the well-heeled of Singaporean society. And in Living with Lydia (LWL) (a program which demonstrates Singapore’s capacity for global integration), Hong Kong émigré Lydia is forced to share a house (less ostentatious than PCK’s) with the family of the hapless Billy B. Ong. There is perhaps no more telling cultural event than the sitcom. In the 1970s, The Brady Bunch told us more about American values and habits than any number of news reports or cop shows. A nation’s identity is uncovered; it bares its soul to us through the daily tribulations of its TV households. In Singapore, home-based sitcoms have been one of the major success stories in local television production with each of these three programs collecting multiple prizes at the region-wide Asian Television Awards. These sitcoms have been able to reflect the ideals and values of the Singaporean nation to audiences both at ‘home’ and abroad. This article explores the worlds of UOR, PCK, and LWL, and the ways in which each of the fictional homes represents key features of the multi-ethnic, multi-cultural Singapore. Through ownership and regulation, Singaporean TV programs operate as a firm link between the state and its citizens. These sitcoms follow regular patterns where the ‘man of the house’ is more buffoon than breadwinner – in a country defined by its neo-Confucian morality, sitcoms allow a temporary subversion of patriarchal structures. In this article I argue that the central theme in Singaporean sitcoms is that while home is a personal space, it is also a valuable site for national identities to be played out. These identities are visible in the physical indicators of the exterior and interior living spaces, and the social indicators representing a benign patriarchy and a dominant English language. Structure One of the key features of sitcoms is the structure: cold open – titles – establishing shot – opening scene. Generally the cold opening (aka “the teaser”) takes place inside the home to quickly (re)establish audience familiarity with the location and the characters. The title sequence then features, in the case of LWL and PCK, the characters outside the house (in LWL this is in cartoon format), and in UOR (see Figure 1) it is the communal space of the barbeque area fronting the multi-story HDB (Housing Development Board) apartment blocks. Figure 1: Under One Roof The establishing shot at the end of each title sequence, and when returning from ad breaks, is an external view of the characters’ respective dwellings. In Seinfeld this establishing shot is the New York apartment block, in Roseanne it is the suburban house, and the Singaporean sitcoms follow the same format (see Figure 2). Figure 2: Phua Chu Kang External Visions of the Home This emphasis on exterior buildings reminds the viewer that Singaporean housing is, in many ways, unique. As a city-state (and a young one at that) its spatial constraints are particularly limiting: there simply isn’t room for suburban housing on quarter acre blocks. It rapidly transformed from an “empty rock” to a scattered Malay settlement of bay and riverside kampongs (villages) recognisable by its stilt houses. Then in the shadow of colonialism and the rise of modernity, the kampongs were replaced in many cases by European-inspired terrace houses. Finally, in the post-colonial era high-rise housing began to swell through the territory, creating what came to be known as the “HDB new town”, with some 90% of the population now said to reside in HDB units, and many others living in private high-rises (Chang 102, 104). Exterior shots used in UOR (see Figure 3) consistently emphasise the distinctive HDB blocks. As with the kampong housing, high-rise apartments continue notions of communal living in that “Living below, above and side by side other people requires tolerance of neighbours and a respect towards the environment of the housing estate for the good of all” (104). The provision of readily accessible public housing was part of the “covenant between the newly enfranchised electorate and the elected government” (Chua 47). Figure 3: Establishing shot from UOR In UOR, we see the constant interruption of the lives of the Tan family by their multi-ethnic neighbours. This occurs to such an extent as to be a part of the normal daily flow of life in Singaporean society. Chang argues that despite the normally interventionist activities of the state, it is the “self-enforcing norms” of behaviour that have worked in maintaining a “peaceable society in high-rise housing” (104). This communitarian attitude even extends to the large gated residence of PCK, home to an almost endless stream of relatives and friends. The gate itself seems to perform no restrictive function. But such a “peaceable society” can also be said to be a result of state planning which extends to the “racial majoritarianism” imposed on HDB units in the form of quotas determining “the actual number of households of each of the three major races [Chinese, Malay and Indian] … to be accommodated in a block of flats” (Chua 55). Issues of race are important in Singapore where “the inscription of media imagery bears the cultural discourse and materiality of the social milieu” (Wong 120) perhaps nowhere more graphically illustrated than in the segregation of TV channels along linguistic / cultural lines. These 3 programs all featured on MediaCorp TV’s predominantly English-language Channel 5 and are, in the words of Roland Barthes, “anchored” by dint of their use of English. Home Will Eat Itself The consumption of home-based sitcoms by audiences in their own living-rooms creates a somewhat self-parodying environment. As John Ellis once noted, it is difficult to escape from the notion that “TV is a profoundly domestic phenomenon” (113) in that it constantly attempts to “include the audiences own conception of themselves into the texture of its programmes” (115). In each of the three Singaporean programs living-rooms are designed to seat characters in front of a centrally located TV set – at most all the audience sees is the back of the TV, and generally only when the TV is incorporated into a storyline, as in the case of PCK in Figure 4 (note the TV set in the foreground). Figure 4: PCK Even in this episode of PCK when the lead characters stumble across a pornographic video starring one of the other lead characters, the viewer only hears the program. Perhaps the most realistic (and acerbic) view of how TV reorganises our lives – both spatially in the physical layout of our homes, and temporally in the way we construct our viewing habits (eating dinner or doing the housework while watching the screen) – is the British “black comedy”, The Royle Family. David Morley (443) notes that “TV and other media have adapted themselves to the circumstances of domestic consumption while the domestic arena itself has been simultaneously redefined to accommodate their requirements”. Morley refers to The Royle Family’s narrative that rests on the idea that “for many people, family life and watching TV have become indistinguishable to the extent that, in this fictional household, it is almost entirely conducted from the sitting positions of the viewers clustered around the set” (436). While TV is a central fixture in most sitcoms, its use is mostly as a peripheral thematic device with characters having their viewing interrupted by the arrival of another character, or by a major (within the realms of the plot) event. There is little to suggest that “television schedules have instigated a significant restructuring of family routines” as shown in Livingstone’s audience-based study of UK viewers (104). In the world of the sitcom, the temporalities of characters’ lives do not need to accurately reflect that of “real life” – or if they do, things quickly descend to the bleakness exemplified by the sedentary Royles. As Scannell notes, “broadcast output, like daily life, is largely uneventful, and both are punctuated (predictably and unpredictably) by eventful occasions” (4). To show sitcom characters in this static, passive environment would be anathema to the “real” viewer, who would quickly lose interest. This is not to suggest that sitcoms are totally benign though as with all genres they are “the outcome of social practices, received procedures that become objectified in the narratives of television, then modified in the interpretive act of viewing” (Taylor 14). In other words, they feature a contextualisation that is readily identifiable to members of an established society. However, within episodes themselves, it as though time stands still – character development is almost non-existent, or extremely slow at best and we see each episode has “flattened past and future into an eternal present in which parents love and respect one another, and their children forever” (Taylor 16). It takes some six seasons before the character of PCK becomes a father, although in previous seasons he acts as a mentor to his nephew, Aloysius. Contained in each episode, in true sitcom style, are particular “narrative lines” in which “one-liners and little comic situations [are] strung on a minimal plot line” containing a minor problem “the solution to which will take 22 minutes and pull us gently through the sequence of events toward a conclusion” (Budd et al. 111). It is important to note that the sitcom genre does not work in every culture, as each locale renders the sitcom with “different cultural meanings” (Nielsen 95). Writing of the failure of the Danish series Three Whores and a Pickpocket (with a premise like that, how could it fail?), Nielsen (112) attributes its failure to the mixing of “kitchen sink realism” with “moments of absurdity” and “psychological drama with expressionistic camera work”, moving it well beyond the strict mode of address required by the genre. In Australia, soap operas Home and Away and Neighbours have been infinitely more popular than our attempts at sitcoms – which had a brief heyday in the 1980s with Hey Dad..!, Kingswood Country and Mother and Son – although Kath and Kim (not studio-based) could almost be counted. Lichter et al. (11) state that “television entertainment can be ‘political’ even when it does not deal with the stuff of daily headlines or partisan controversy. Its latent politics lie in the unavoidable portrayal of individuals, groups, and institutions as a backdrop to any story that occupies the foreground”. They state that US television of the 1960s was dominated by the “idiot sitcom” and that “To appreciate these comedies you had to believe that social conventions were so ironclad they could not tolerate variations. The scripts assumed that any minute violation of social conventions would lead to a crisis that could be played for comic results” (15). Series like Happy Days “harked back to earlier days when problems were trivial and personal, isolated from the concerns of a larger world” (17). By the late 1980s, Roseanne and Married…With Children had “spawned an antifamily-sitcom format that used sarcasm, cynicism, and real life problems to create a type of in-your-face comedy heretofore unseen on prime time” (20). This is markedly different from the type of values presented in Singaporean sitcoms – where filial piety and an unrelenting faith in the family unit is sacrosanct. In this way, Singaporean sitcoms mirror the ideals of earlier US sitcoms which idealise the “egalitarian family in which parental wisdom lies in appeals to reason and fairness rather than demands for obedience” (Lichter et al. 406). Dahlgren notes that we are the products of “an ongoing process of the shaping and reshaping of identity, in response to the pluralised sets of social forces, cultural currents and personal contexts encountered by individuals” where we end up with “composite identities” (318). Such composite identities make the presentation (or re-presentation) of race problematic for producers of mainstream television. Wong argues that “Within the context of PAP hegemony, media presentation of racial differences are manufactured by invoking and resorting to traditional values, customs and practices serving as symbols and content” (118). All of this is bound within a classificatory system in which each citizen’s identity card is inscribed as Chinese, Malay, Indian or Other (often referred to as CMIO), and a broader social discourse in which “the Chinese are linked to familial values of filial piety and the practice of extended family, the Malays to Islam and rural agricultural activities, and the Indians to the caste system” (Wong 118). However, these sitcoms avoid directly addressing the issue of race, preferring to accentuate cultural differences instead. In UOR the tables are turned when a none-too-subtle dig at the crude nature of mainland Chinese (with gags about the state of public toilets), is soon turned into a more reverential view of Chinese culture and business acumen. Internal Visions of the Home This reverence for Chinese culture is also enacted visually. The loungeroom settings of these three sitcoms all provide examples of the fashioning of the nation through a “ubiquitous semi-visibility” (Noble 59). Not only are the central characters in each of these sitcoms constructed as ethnically Chinese, but the furnishings provide a visible nod to Chinese design in the lacquered screens, chairs and settees of LWL (see Figure 5.1), in the highly visible pair of black inlaid mother-of-pearl wall hangings of UOR (see Figure 5.2) and in the Chinese statuettes and wall-hangings found in the PCK home. Each of these items appears in the central view of the shows most used setting, the lounge/family room. There is often symmetry involved as well; the balanced pearl hangings of UOR are mirrored in a set of silk prints in LWL and the pair of ceramic Chinese lions in PCK. Figure 5.1: LWL Figure 5.2: UOR Thus, all three sitcoms feature design elements that reflect visible links to Chinese culture and sentiments, firmly locating the sitcoms “in Asia”, and providing a sense of the nation. The sets form an important role in constructing a realist environment, one in which “identification with realist narration involves a temporary merger of at least some of the viewer’s identity with the position offered by the text” (Budd et al. 110). These constant silent reminders of the Chinese-based hegemon – the cultural “majoritarianism” – anchors the sitcoms to a determined concept of the nation-state, and reinforces the “imaginative geographies of home” (Blunt and Dowling 247). The Foolish “Father” Figure in a Patriarchal Society But notions of a dominant Chinese culture are dealt with in a variety of ways in these sitcoms – not the least in a playful attitude toward patriarchal figures. In UOR, the Tan family “patriarch” is played by Moses Lim, in PCK, Gurmit Singh plays Phua and in LWL Samuel Chong plays Billy B. Ong (or, as Lydia mistakenly refers to him Billy Bong). Erica Sharrer makes the claim that class is a factor in presenting the father figure as buffoon, and that US sitcoms feature working class families in which “the father is made to look inept, silly, or incompetent have become more frequent” partly in response to changing societal structures where “women are shouldering increasing amounts of financial responsibility in the home” (27). Certainly in the three series looked at here, PCK (the tradesman) is presented as the most derided character in his role as head of the household. Moses Lim’s avuncular Tan Ah Teck is presented mostly as lovably foolish, even when reciting his long-winded moral tales at the conclusion of each episode, and Billy B. Ong, as a middle-class businessman, is presented more as a victim of circumstance than as a fool. Sharrer ponders whether “sharing the burden of bread-winning may be associated with fathers perceiving they are losing advantages to which they were traditionally entitled” (35). But is this really a case of males losing the upper hand? Hanke argues that men are commonly portrayed as the target of humour in sitcoms, but only when they “are represented as absurdly incongruous” to the point that “this discursive strategy recuperates patriarchal notions” (90). The other side of the coin is that while the “dominant discursive code of patriarchy might be undone” (but isn’t), “the sitcom’s strategy for containing women as ‘wives’ and ‘mothers’ is always contradictory and open to alternative readings” (Hanke 77). In Singapore’s case though, we often return to images of the women in the kitchen, folding the washing or agonising over the work/family dilemma, part of what Blunt and Dowling refer to as the “reproduction of patriarchal and heterosexist relations” often found in representations of “the ideal’ suburban home” (29). Eradicating Singlish One final aspect of these sitcoms is the use of language. PM Lee Hsien Loong once said that he had no interest in “micromanaging” the lives of Singaporeans (2004). Yet his two predecessors (PM Goh and PM Lee Senior) both reflected desires to do so by openly criticising the influence of Phua Chu Kang’s liberal use of colloquial phrases and phrasing. While the use of Singlish (or Singapore Colloquial English / SCE) in these sitcoms is partly a reflection of everyday life in Singapore, by taking steps to eradicate it through the Speak Good English movement, the government offers an intrusion into the private home-space of Singaporeans (Ho 17). Authorities fear that increased use of Singlish will damage the nation’s ability to communicate on a global basis, withdrawing to a locally circumscribed “pidgin English” (Rubdy 345). Indeed, the use of Singlish in UOR is deliberately underplayed in order to capitalise on overseas sales of the show (which aired, for example, on Australia’s SBS television) (Srilal). While many others have debated the Singlish issue, my concern is with its use in the home environment as representative of Singaporean lifestyles. As novelist Hwee Hwee Tan (2000) notes: Singlish is crude precisely because it’s rooted in Singapore’s unglamorous past. This is a nation built from the sweat of uncultured immigrants who arrived 100 years ago to bust their asses in the boisterous port. Our language grew out of the hardships of these ancestors. Singlish thus offers users the opportunity to “show solidarity, comradeship and intimacy (despite differences in background)” and against the state’s determined efforts to adopt the language of its colonizer (Ho 19-20). For this reason, PCK’s use of Singlish iterates a “common man” theme in much the same way as Paul Hogan’s “Ocker” image of previous decades was seen as a unifying feature of mainstream Australian values. That the fictional PCK character was eventually “forced” to take “English” lessons (a storyline rapidly written into the program after the direct criticisms from the various Prime Ministers), is a sign that the state has other ideas about the development of Singaporean society, and what is broadcast en masse into Singaporean homes. Conclusion So what do these home-based sitcoms tell us about Singaporean nationalism? Firstly, within the realms of a multiethnic society, mainstream representations reflect the hegemony present in the social and economic structures of Singapore. Chinese culture is dominant (albeit in an English-speaking environment) and Indian, Malay and Other cultures are secondary. Secondly, the home is a place of ontological security, and partial adornment with cultural ornaments signifying Chinese culture are ever-present as a reminder of the Asianness of the sitcom home, ostensibly reflecting the everyday home of the audience. The concept of home extends beyond the plywood-prop walls of the soundstage though. As Noble points out, “homes articulate domestic spaces to national experience” (54) through the banal nationalism exhibited in “the furniture of everyday life” (55). In a Singaporean context, Velayutham (extending the work of Morley) explores the comforting notion of Singapore as “home” to its citizens and concludes that the “experience of home and belonging amongst Singaporeans is largely framed in the materiality and social modernity of everyday life” (4). Through the use of sitcoms, the state is complicit in creating and recreating the family home as a site for national identities, adhering to dominant modes of culture and language. References Blunt, Alison, and Robyn Dowling. Home. London: Routledge, 2006. Budd, Mike, Steve Craig, and Clay Steinman. Consuming Environments: Television and Commercial Culture. New Jersey: Rutgers UP, 1999. Chang, Sishir. “A High-Rise Vernacular in Singapore’s Housing Development Board Housing.” Berkeley Planning Journal 14 (2000): 97-116. Chua, Beng Huat. “Public Housing Residents as Clients of the State.” Housing Studies 15.1 (2000). Dahlgren, Peter. “Media, Citizenship and Civic Culture”. Mass Media and Society. 3rd ed. Eds. James Curran and Michael Gurevitch. London: Arnold, 2000. 310-328. Ellis, John. Visible Fictions: Cinema, Television, Video. London: Routledge & Kegan Paul, 1982. Hanke, Robert. “The ‘Mock-Macho’ Situation Comedy: Hegemonic Masculinity and its Reiteration.” Western Journal of Communication 62.1 (1998). Ho, Debbie G.E. “‘I’m Not West. I’m Not East. So How Leh?’” English Today 87 22.3 (2006). Lee, Hsien Loong. “Our Future of Opportunity and Promise.” National Day Rally 2004 Speech. 29 Apr. 2007 http://www.gov.sg/nd/ND04.htm>. Lichter, S. Robert, Linda S. Lichter, and Stanley Rothman. Prime Time: How TV Portrays American Culture. Washington D.C.: Regnery Publishing, 1994. Livingstone, Sonia. Young People and New Media: Childhood and the Changing Media Environment. London: Sage, 2002 Morley, David. “What’s ‘Home’ Got to Do with It? Contradictory Dynamics in the Domestication of Technology and the Dislocation of Domesticity.” European Journal of Cultural Studies 6 (2003). Noble, Greg. “Comfortable and Relaxed: Furnishing the Home and Nation.” Continuum: Journal of Media and Cultural Studies 16.1 (2002). Rubdy, Rani. “Creative Destruction: Singapore’s Speak Good English Movement.” World Englishes 20.3 (2001). Scannell, Paddy. “For a Phenomenology of Radio and Television.” Journal of Communication 45.3 (1995). Scharrer, Erica. “From Wise to Foolish: The Portrayal of the Sitcom Father, 1950s-1990s.” Journal of Broadcasting and Electronic Media 45.1 (2001). Srilal, Mohan. “Quick Quick: ‘Singlish’ Is Out in Re-education Campaign.” Asia Times Online (28 Aug. 1999). Tan, Hwee Hwee. “A War of Words over ‘Singlish’: Singapore’s Government Wants Its Citizens to Speak Good English, But They Would Rather Be ‘Talking Cock’.” Time International 160.3 (29 July 2002). Taylor, Ella. “From the Nelsons to the Huxtables: Genre and Family Imagery in American Network Television.” Qualitative Sociology 12.1 (1989). Velayutham, Selvaraj. “Affect, Materiality, and the Gift of Social Life in Singapore.” SOJOURN 19.1 (2004). Wong, Kokkeong. Media and Culture in Singapore: A Theory of Controlled Commodification. New Jersey: Hampton Press, 2001. Images Under One Roof: The Special Appearances. Singapore: Television Corporation of Singapore. VCD. 2000. Living with Lydia (Season 1, Volume 1). Singapore: MediaCorp Studios, Blue Max Enterprise. VCD. 2001. Phua Chu Kang Pte Ltd (Season 5, Episode 10). Kuala Lumpur: MediaCorp Studios, Speedy Video Distributors. VCD. 2003. Citation reference for this article MLA Style Pugsley, Peter. "At Home in Singaporean Sitcoms: Under One Roof, Living with Lydia and Phua Chu Kang." M/C Journal 10.4 (2007). echo date('d M. Y'); ?> <http://journal.media-culture.org.au/0708/09-pugsley.php>. APA Style Pugsley, P. (Aug. 2007) "At Home in Singaporean Sitcoms: Under One Roof, Living with Lydia and Phua Chu Kang," M/C Journal, 10(4). Retrieved echo date('d M. Y'); ?> from <http://journal.media-culture.org.au/0708/09-pugsley.php>.
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Dissertations / Theses on the topic "Silent bgl operon"

1

Vashishtha, Kartika. "Deciphering the evolutionary significance of maintaining cryptic genetic systems by bacteria." Thesis, 2019. https://etd.iisc.ac.in/handle/2005/5065.

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Abstract:
Cryptic genes are phenotypically silent DNA sequences with the potential to code for a function, but remain inactive during the normal life span of the organism. However they can be activated by a single mutational event such as recombination, deletion, insertions or point mutation, resulting in a discernible phenotype. The bgl operon of E. coli, involved in the uptake and breakdown of plant derived aromatic -glucosides salicin and arbutin, is one of the well studied examples of cryptic genetic systems. The present study was aimed at understanding the causes for the conservation of the silent bgl operon without being lost over evolutionary time. Antimicrobial resistance is one of the most serious problems in the clinical context since microorganisms are equipped with distinct defense mechanisms to meet the challenges posed by the widespread presence of antibiotics in the environment. The non-heritable transient phenomenon of resisting low doses of antibiotics is broadly termed as phenotypic antibiotic resistance. It has been observed earlier that wild type E. coli shows phenotypic antibiotic resistance when exposed to salicylate and related compounds by inducing the expression of the marRAB (multiple antibiotic resistance) operon. Salicylate being structurally similar to the breakdown products of the β-glucosides salicin and arbutin, viz. saligenin and hydroquinone respectively, suggested the possibility that bacteria having the functional form of the bgl operon and are actively metabolizing salicin, can exhibit phenotypic antibiotic resistance. Results presented in Chapter 2 show that E. coli and Klebsiella strains carrying inducible or constitutive form of the bgl operon show marA dependent antibiotic resistance to low doses of antibiotics through enhanced expression of different multidrug efflux pumps. The aglycone product released during salicin metabolism viz. saligenin is responsible for conferring the phenotype. The prolonged state of low level of resistance can give rise to a genetically resistant population of mutants as the frequency of mutants that show heritable resistance increases when Bgl+ bacteria are exposed to salicin and sub-lethal doses of nalidixic acid. Most of the identified mutations were clinically relevant and primarily localized to the QRD (quinolone resistance determining region) locus of the gyrA subunit of DNA gyrase. There was no fitness cost associated with genetic resistance as the mutants showed no growth disadvantage in competition experiments performed between the sensitive parent and the mutants. These findings indicate that presence of the activated form of the bgl operon in the genome facilitates the survival of bacteria in environments in which both aromatic β-glucosides as well as antibiotics are present. In addition to facilitating β-glucosides metabolism, the activated bgl operon has been shown to confer growth advantage in stationary phase by enhancing the metabolic capability of the cell. BglG, the positive regulator of the operon, has been implicated in the regulation of several downstream target genes in stationary phase. BglG is a sequence specific RNA binding protein that binds as a homodimer at a 32 nucleotide long sequence termed as ribonucleic antiterminator (RAT). A genome wide comparative transcriptome analysis of ΔbglG and bglG (WT) strains performed earlier revealed that bglG deletion led to down-regulation of several metabolic pathways including lipopolysaccharide (LPS) biosynthesis. The downregulation of LPS biosynthesis pathway resulted in a permeability defect in the bglG deletion strain. Studies described in Chapter 3 addresses the morphological changes associated with the ΔbglG strain and the mechanistic details of the regulation of the genes involved in LPS synthesis and transport by BglG in stationary phase. The DNA binding transcription factor GadE, involved in the regulation of genes required for pH maintenance, was significantly downregulated in the bglG deletion strain as seen in the transcriptome analysis described above. Earlier studies have also shown that gadE is one of the key positive regulators of genes involved in LPS core biosynthesis. Using electrophoretic mobility shift assays it could be demonstrated that BglG binds gadE mRNA that carries a putative RAT sequence and the binding increases the stability of gadE mRNA by an unknown mechanism. Partial loss in permeability barrier of the strain was also observed upon deletion of gadE. These observations suggest that GadE is one of the downstream targets of BglG and brings about the regulation of the composition of cell wall in stationary phase. One possible reason for the retention of the silent form of the bgl operon in wild isolates is a fitness cost associated with the activated form under nonselective conditions. Work presented in Appendix was an attempt to investigate the possibility of the activated form of the operon conferring a growth disadvantage under nonselective conditions such as exponential growth phase in nutrient rich media. Exponential growth phase competition experiments using strains of different bgl genotypes could not identify any distinct growth disadvantage associated with the Bgl+ strain at least under the conditions tested. In light of these observations the epilogue section highlights how the bgl operon appears to be a dynamic component of the genome and its involvement in multiple survival strategies is expected to provide a strong selective force for its maintenance in the genome
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