The ability of Schistosoma mansoni to escape oxidative damage from immune system-generated reactive oxygen intermediates has been extensively documented. The limiting step in the parasite's detoxification process appears to be at the level of hydrogen peroxide neutralization. In the present study, the possible role of a novel class of antioxidant enzymes, thioredoxin peroxidase (TPx), in hydrogen peroxide neutralization by schistosomes was investigated. An expressed sequence tag was characterized from the Schistosoma Genome Initiative with high similarity to TPx from other organisms. The gene encodes a polypeptide containing 2 conserved active-site cysteines and flanking amino acids, and 60-70% identity with previously characterized TPx proteins. Recombinant schistosome TPx was enzymatically active and found to have thioredoxin-dependent hydrogen peroxide reducing activity of 4500 nmol hydrogen peroxide/min/mg protein. Native TPx activity was determined to be 48.1 nmol hydrogen peroxide/min/mg protein in adult worm homogenates compared with 46.9 for glutathione peroxidase. TPx activity was precipitated from adult worm homogenates with antibodies prepared against the recombinant protein. Western blotting with antibodies made against recombinant protein showed that TPx was expressed in both male and female adult worms. This is the first demonstration of a TPx activity in schistosomes and our results suggest that TPx plays a significant role in schistosome-host interactions.
Pod powierzchnią świata, poza historią -ku kontrhistorii odpadów i ziemi jałowej The article is a collage of texts concerning the phenomena of waste in context underworld, underground and underhistory. Starting from environmentalism, cultural studies, sociology and psychoanalysis, the author moves towards a wide array of contemporary art practices. 'Garbage', 'trash', 'refuse', 'waste' and 'rubbish' are presented as complex and ambivalent metaphorical terms employed to organize and legitimize the parts of life normally desired to be overlooked. Waste: the excessive remainder of production and consumption, detritus of that which is deemed 'use-less' in 'progress'; the informe material that has been reappropriated and recycled in countless artworks since the collages of Cubism, Dada and Surrealism's détournements of objets trouvés. The author goes deeper: in order to present a global consciousness, he introduces a spectrum of artists and art works concerned with waste's constitutive presence in and implications for contemporary landscapes, both literal and cultural. His description includes land artists, environmental artists, activists and conceptualists, such as Alan Sonfist, Agnes Denes, Agnès Varda, Edward Burtynsky, Maurizio Cattelan, and Mierle Laderman Ukeles. Gdzieś / tu (1): sieć widmoGdzieś tam, tak daleko / tak blisko sieć widmo dryfuje pod powierzchnią oceanu. Widziana z dystansu wydaje się unoszącą się w toni wyspą albo małą, tnącą powierzchnię wody rafą. Jednak z bliska, kiedy ________________________ 1 Niniejszy kolaż tekstów napisany został z inspiracji rosnącego zainteresowania odpadami nie tylko w dyskusjach związanych z ochroną środowiska, ale również w nauce o kulturze, archeologii, socjologii, psychologii i psychoanalizie, a także częstego ich użycia przez współczesnych artystów. Doprowadziła mnie do niego także długoletnia obserwacja wpływu zglobalizowanych korporacji i zorganizowanego świata przestępczego na obieg materii. Jej cyrkulacja prowadzi do tworzenia nowych zjawisk przyrodniczych, jakimi są rozległe, pełne odpadów, toksyczne krajobrazy. Wreszcie bezpośrednią inspiracją do napisania tego tekstu były rozmowy z kolegami i studentami, a także dyskusje, które toczyliśmy m.in. na konferencji Landscape and Environment ("Krajobraz i środowisko"), odbywającej się w czerwcu 2009 na Uniwersytecie Aberystwyth w Walii (koordynatorzy -prof. Mike Pearson i dr Heike Roms). Powiązane tematycznie teksty, które uznać można za część tego samego projektu, publikowałem w Wielkiej Brytanii m.in. na łamach "Performance Research" 2010, r. 15 Cienie historiiŚmieci, odpadki, odrzuty czy nieczystości to słowa o złożonych sensach, ambiwalentne i metaforyczne. Wieloznaczność tych i podobnych im określeń pozwala na używanie ich w celu organizowania i sankcjonowania sposobu, w jaki traktowane są te spośród elementów rzeczywistości, które planowo mają zostać przeoczone 2 . Jako zbyteczne produkty wytwarzania i konsumpcji są odrzucane na wszystkich etapach planowego porządkowania. Jeśli produkuje się zbyt wiele i p...
The first cavern described in this paper is situated at Uphill, at the very western extremity of the Mendip Hills. Its present entrance is about midway in a mural face of transition limestone, about a hundred feet high. The fissure leading into it is nearly vertical, and was discovered by some quarry-men casually intersecting it. Some bones and teeth being found there, the author was induced to pursue the exploration of the fissure; in the course of which he discovered bones of the rhinoceros, hyæna, bear, ox, horse, hog, fox, polecat, rat and mouse, and also of birds. The bones of the animals of the larger species were so gnawed and splintered, and evidently of such ancient fracture, that no doubt could exist of the cave having been a hyæna’s den, similar to Kirkdale and Kent’s Hole. All the ancient remains were found in the upper regions of the fissure, and were so firmly imbedded in the detritus, as not to be extracted without difficulty with the pick-axe. Further on he found a wet tenacious loam, abounding with an innumerable quantity of bones, belonging exclusively to birds. After working six days he came to a cavern, ten or twelve feet high, extending about forty feet from north to south, and varying from eight to twenty feet from east to west; the floor of which was covered with bones of sheep: and on digging into the mud and sand of which it consisted, the bones of sheep, birds, cuttle-fish, and foxes, were discovered. Some fine stalactites depended from the roof, and partial spots of stalagmite appeared on the floor. In a fissure that branched from the mouth of the main entrance there were found, among the sand, a piece of black Roman pottery, and two coins, one of Didius Julianus, and the other of Julia Mammæa, together with bones of sheep, cuttle-fish, foxes, and birds. The author considers that there exist evidences of the operation of water at three distinct periods of time:—the first indicated by the bones of the hyæna, and the other gnawed bones firmly imbedded in the diluvial detritus: the second, when sand was deposited by the sea in the second fissure, that washed in through the vertical chimney, and that inundated the whole valley up to Glastonbury: the third irruption of the sea occurring within these fifteen hundred years, and choking up the adit from the level by which the sheep and foxes had entered, floating in the bones of the cuttlefish, and depositing the thin crust of mud which covered the sand. The coins and pottery he supposes to have been introduced through this entrance from the level.
Excavation in Area 1 identified an enclosed settlement of Middle–Late Iron Age and Early Roman date, which included a roundhouse gully and deep storage pits with complex fills. A group of undated four-post structures, situated in the east of Area 1, appeared to represent a specialised area of storage or crop processing of probable Middle Iron Age date. A sequence of re-cutting and reorganisation of ditches and boundaries in the Late Iron Age/Early Roman period was followed, possibly after a considerable hiatus, by a phase of later Roman activity, Late Iron Age reorganisation appeared to be associated with the abandonment of a roundhouse, and a number of structured pit deposits may also relate to this period of change. Seven Late Iron Age cremation burials were associated with a contemporary boundary ditch which crossed Area 1. Two partly-exposed, L-shaped ditches may represent a later Roman phase of enclosed settlement and a slight shift in settlement focus. An isolated inhumation burial within the northern margins of Area 1 was tentatively dated by grave goods to the Early Saxon period.<br/> Area 2 contained a possible trackway and field boundary ditches, of which one was of confirmed Late Iron Age/Early Roman date. A short posthole alignment in Area 2 was undated, and may be an earlier prehistoric feature.
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