Type I DNA restriction/modification systems are oligomeric enzymes capable of switching between a methyltransferase function on hemimethylated host DNA and an endonuclease function on unmethylated foreign DNA. They have long been believed to not turnover as endonucleases with the enzyme becoming inactive after cleavage. Cleavage is preceded and followed by extensive ATP hydrolysis and DNA translocation. A role for dissociation of subunits to allow their reuse has been proposed for the EcoR124I enzyme. The EcoKI enzyme is a stable assembly in the absence of DNA, so recycling was thought impossible. Here, we demonstrate that EcoKI becomes unstable on long unmethylated DNA; reuse of the methyltransferase subunits is possible so that restriction proceeds until the restriction subunits have been depleted. We observed that RecBCD exonuclease halts restriction and does not assist recycling. We examined the DNA structure required to initiate ATP hydrolysis by EcoKI and find that a 21-bp duplex with single-stranded extensions of 12 bases on either side of the target sequence is sufficient to support hydrolysis. Lastly, we discuss whether turnover is an evolutionary requirement for restriction, show that the ATP hydrolysis is not deleterious to the host cell and discuss how foreign DNA occasionally becomes fully methylated by these systems.
In Jean-Paul Sartre's Being and Nothingness (2003: 10), he posits that all consciousness is intentional. For Sartre, consciousness is never a thing unto itself, but is always consciousness of something. He proposes 'consciousness (of)' as a means of articulating the experience of consciousness: the bracketing of the 'of' fulfilling a grammatical function only, with consciousness only ever being that which it is directed towards. To taste strawberries is not to have a consciousness that encounters the perception of the strawberry, but a 'consciousness=strawberry', with a playful deferral back and forth between the two, which mutually constitute one another.In the same way, we might consider the embodied consciousness of the tongue. To attempt to taste your own tongue is a self-reflexive act, where the apparatus of tasting turns back upon itself, unable to recognize itself in its act of self-perception. In this small act of rolling the tongue back upon itself, the nothingness or abyss at the centre of Being is exposed, brought into the open, its absence given a presence in experience. To taste is always intentional; it is always directed towards something. And it is from this premise of the inability to taste one's own tongue that this article proceeds.Using numerous performances that have made food a central component of the work, this article will explore how food, eating and taste can be used in performance to explore the relationship to, and constitution of, the Other. For Sartre, the relationship between Self and Other is a relationship of mutual constitution, developing from Heidegger's understanding of the continuum of Being-in-the-world (1962: 78). What Sartre adds to this discourse is to move beyond the relationship between the subject (Being, Dasein) and the objectal world to the relationship between subjects. And it is this Other that constitutes the consciousness of the Self; 'consciousness (of)' is always directed towards an Other. This article explores how food, as an intermediary, allows for the mutual exploration and constitution of the Self and the Other. The article is split into three sections: experiencing the Other through the food object, experiencing the Other in the food object and experiencing the Other as the food object.
In Michel Serres’ The Five Senses: A Philosophy of Mingled Bodies, he establishes an opposition between two mouths: the anaesthetising, speaking mouth of discourse and analysis and the aesthetic, tasting mouth of sensation. This article uses Serres’ model of the two mouths to think about the performance of knowledge and philosophy in a sensory performance event and the potential of intoxication to unveil or reveal through a process of ‘making strange’. The article begins with an outline and reading of Serres, considering his writing on the two mouths and their indicative models of knowledge, before moving to think about philosophies of confluence or confusion; the pouring or flowing together of different forms of knowing. This is coupled with outlining two modes of intoxication (losing oneself into the status quo and a process of estrangement) to think about the politics of aesthetic sensory experience in the age of commodification of live(d) experience. The second half of the article turns to a dining-performance event by Kaye Winwood entitled After Dark (2016). The event is used as a basis for more personal reflections, considering the ways intoxication makes strange and enters into performance as a revelatory experience. The article proposes a number of interconnected arguments: that sensory experience and embodiment offer a mode of knowledge; that intoxication as ‘making strange’ has potential as a philosophical gesture; and that in that estrangement, there is potential to resist the coopting of live(d) or sensory experience in an economy of commodification.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.