The Reste of Translation: Derrida and the Remains

University of Technology Sydney. Faculty of Arts and Social Sciences.When Derrida describes the act of translation as both possible and impossible, he articulates a theme that runs throughout much of his work and deconstruction in general. On the one hand, Derrida is arguing that there is a certain impossibility at the heart of the event or act of translation; a perfect or complete translation would rend the sign, the writing itself, irrelevant and the text would disappear into the perfect comprehension of the meaning. Yet, importantly, Derrida does not deny that translation is also possible, that language can and does communicate something. The tension between the two helps us to understand how language works, to see the potential signifieds in the sign and to attempt to transport, to convey them across into the new language. Yet it stops short the inherent violence in the act of translation: the attempt to capture that which is foreign or different, to welcome it in as guest and seek to homogenise the text and minimise difference and otherness. The impossibility of translation is not an isolated part of the broader work of Derrida’s oeuvre or deconstruction more generally. The movement of deconstruction as it solicits, shakes, and undermines the foundational understanding of the sign is that which also leads Derrida to conclude on the impossibility of translation. Derrida’s numerous engagements with the concept of translation and the numerous works by other philosophers and academics reveal the importance of translation to Derrida’s work and how his quasi-transcendentals impact and influence translation studies to this day. Where this thesis departs from the field and makes an original contribution is through its examination of Derrida’s use of , in particular how Derrida explores it throughout works such as . If translation is, at its heart, an attempt to use totalising force on the foreign, then the cinder is what remains after the violence, after the holocaust [all is burned]. Yet, translation is ultimately a route of passage where the foreign comes as a guest, making translation a site of hospitality. The dual bind of the possibility and impossibility of translation presents itself as a decision in the Derridean sense of an undecidable. Unable to capture the sign and allow it to retain its foreigness, I argue that ‘the remains’ is what escapes the ethical decision between the text as singular guest and the target language of the host as the universal

Resolving the contributions of the membrane-bound and periplasmic nitrate reductase systems to nitric oxide and nitrous oxide production in Salmonella enterica serovar Typhimurium

The production of cytotoxic nitric oxide (NO) and conversion into the neuropharmacological agent and potent greenhouse gas nitrous oxide (N2O) is linked with anoxic nitrate catabolism by Salmonella enterica serovar Typhimurium. Salmonella can synthesize two types of nitrate reductase: a membrane-bound form (Nar) and a periplasmic form (Nap). Nitrate catabolism was studied under nitrate-rich and nitrate-limited conditions in chemostat cultures following transition from oxic to anoxic conditions. Intracellular NO production was reported qualitatively by assessing transcription of the NO-regulated genes encoding flavohaemoglobin (Hmp), flavorubredoxin (NorV) and hybrid cluster protein (Hcp). A more quantitative analysis of the extent of NO formation was gained by measuring production of N2O, the end-product of anoxic NO-detoxification. Under nitrate-rich conditions, the nar, nap, hmp, norV and hcp genes were all induced following transition from the oxic to anoxic state, and 20% of nitrate consumed in steady-state was released as N2O when nitrite had accumulated to millimolar levels. The kinetics of nitrate consumption, nitrite accumulation and N2O production were similar to those of wild-type in nitrate-sufficient cultures of a nap mutant. In contrast, in a narG mutant, the steady-state rate of N2O production was ~30-fold lower than that of the wild-type. Under nitrate-limited conditions, nap, but not nar, was up-regulated following transition from oxic to anoxic metabolism and very little N2O production was observed. Thus a combination of nitrate-sufficiency, nitrite accumulation and an active Nar-type nitrate reductase leads to NO and thence N2O production, and this can account for up to 20% of the nitrate catabolized

NsrR: a key regulator circumventing Salmonella enterica serovar Typhimurium oxidative and nitrosative stress in vitro and in IFN-γ-stimulated J774.2 macrophages

Over the past decade, the flavohaemoglobin Hmp has emerged as the most significant nitric oxide (NO)-detoxifying protein in many diverse micro-organisms, particularly pathogenic bacteria. Its expression in enterobacteria is dramatically increased on exposure to NO and other agents of nitrosative stress as a result of transcriptional regulation of hmp gene expression, mediated by (at least) four regulators. One such regulator, NsrR, has recently been shown to be responsible for repression of hmp transcription in the absence of NO in Escherichia coli and Salmonella, but the roles of other members of this regulon in Salmonella, particularly in surviving nitrosative stresses in vitro and in vivo, have not been elucidated. This paper demonstrates that an nsrR mutant of Salmonella enterica Serovar Typhimurium expresses high levels of Hmp both aerobically and anaerobically, exceeding those that can be elicited in vitro by supplementing media with S-nitrosoglutathione (GSNO). Elevated transcription of ytfE, ygbA, hcp and hcp is also observed, but no evidence was obtained for tehAB upregulation. The hyper-resistance to GSNO of an nsrR mutant is attributable solely to Hmp, since an nsrR hmp double mutant has a wild-type phenotype. However, overexpression of NsrR-regulated genes other than hmp confers some resistance of respiratory oxygen consumption to NO. The ability to enhance, by mutating NsrR, Hmp levels without recourse to exposure to nitrosative stress was used to test the hypothesis that control of Hmp levels is required to avoid oxidative stress, Hmp being a potent generator of superoxide. Within IFN-γ-stimulated J774.2 macrophages, in which high levels of nitrite accumulated (indicative of NO production) an hmp mutant was severely compromised in survival. Surprisingly, under these conditions, an nsrR mutant (as well as an nsrR hmp double mutant) was also disadvantaged relative to the wild-type bacteria, attributable to the combined oxidative effect of the macrophage oxidative burst and Hmp-generated superoxide. This explanation is supported by the sensitivity in vitro of an nsrR mutant to superoxide and peroxide. Fur has recently been confirmed as a weak repressor of hmp transcription, and a fur mutant was also compromised for survival within macrophages even in the absence of elevated NO levels in non-stimulated macrophages. The results indicate the critical role of Hmp in protection of Salmonella from nitrosative stress within and outside macrophages, but also the key role of transcriptional regulation in tuning Hmp levels to prevent exacerbation of the oxidative stress encountered in macrophages

Nitrous oxide production in soil isolates of nitrate-ammonifying bacteria

Here we provide the first demonstration of the potential for N2O production by soil-isolated nitrate-ammonifying bacteria under different C and N availabilities, building on characterizations informed from model strains. The potential for soil-isolated Bacillus sp. and Citrobacter sp. to reduce NO3-, and produce NH4+, NO2- and N2O was examined in batch and continuous (chemostat) cultures under different C-to-NO3- ratios, NO3--limiting (5 mM) and NO3--sufficient (22 mM) conditions. C-to-NO3- ratio had a major influence on the products of nitrate ammonification, with NO2-, rather than NH4+, being the major product at low C-to-NO3- ratios in batch cultures. N2O production was maximum and accompanied by high NO2- production under C-limitation/NO3-sufficiency conditions in chemostat cultures. In media with lower C-to-NO3-N ratios (5- and 10-to-1) up to 2.7% or 5.0% of NO3- was reduced to N2O by Bacillus sp. and Citrobacter sp., respectively, but these reduction efficiencies were only 0.1% or 0.7% at higher C-to-NO3- ratios (25- and 50-to-1). As the highest N2O production did not occur under the same C-to-NO3- conditions as highest NH4+ production we suggest that a re-evaluation may be necessary of the environmental conditions under which nitrate ammonification contributes to N2O emission from soil

The production and detoxification of a potent cytotoxin, nitric oxide, by pathogenic enteric bacteria

The nitrogen cycle is based on several redox reactions that are mainly accomplished by prokaryotic organisms, some archaea and a few eukaryotes, which use these reactions for assimilatory, dissimilatory or respiratory purposes. One group is the Enterobacteriaceae family of Gammaproteobacteria, which have their natural habitats in soil, marine environments or the intestines of humans and other warm-blooded animals. Some of the genera are pathogenic and usually associated with intestinal infections. Our body possesses several physical and chemical defence mechanisms to prevent pathogenic enteric bacteria from invading the gastrointestinal tract. One response of the innate immune system is to activate macrophages, which produce the potent cytotoxin nitric oxide (NO). However, some pathogens have evolved the ability to detoxify NO to less toxic compounds, such as the neuropharmacological agent and greenhouse gas nitrous oxide (N2O), which enables them to overcome the host's attack. The same mechanisms may be used by bacteria producing NO endogenously as a by-product of anaerobic nitrate respiration. In the present review, we provide a brief introduction into the NO detoxification mechanisms of two members of the Enterobacteriaceae family: Escherichia coli and Salmonella enterica serovar Typhimurium. These are discussed as comparative non-pathogenic and pathogenic model systems in order to investigate the importance of detoxifying NO and producing N2O for the pathogenicity of enteric bacteria