ADP-Ribose-1"-Monophosphatase: a Conserved Coronavirus Enzyme That Is Dispensable for Viral Replication in Tissue Culture

Replication of the ~30-kb plus-strand RNA genome of coronaviruses and synthesis of an extensive set of subgenome-length RNAs are mediated by the replicase-transcriptase, a membrane-bound protein complex containing several cellular proteins and up to 16 viral nonstructural proteins (nsps) with multiple enzymatic activities, including protease, polymerase, helicase, methyltransferase, and RNase activities. To get further insight into the replicase gene-encoded functions, we characterized the coronavirus X domain, which is part of nsp3 and has been predicted to be an ADP-ribose-1"-monophosphate (Appr-1"-p) processing enzyme. Bacterially expressed forms of human coronavirus 229E (HCoV-229E) and severe acute respiratory syndrome-coronavirus X domains were shown to dephosphorylate Appr-1"-p, a side product of cellular tRNA splicing, to ADP-ribose in a highly specific manner. The enzyme had no detectable activity on several other nucleoside phosphates. Guided by the crystal structure of AF1521, an X domain homolog from Archaeoglobus fulgidus, potential active-site residues of the HCoV-229E X domain were targeted by site-directed mutagenesis. The data suggest that the HCoV-229E replicase polyprotein residues, Asn 1302, Asn 1305, His 1310, Gly 1312, and Gly 1313, are part of the enzyme's active site. Characterization of an Appr-1"-pase-deficient HCoV-229E mutant revealed no significant effects on viral RNA synthesis and virus titer, and no reversion to the wild-type sequence was observed when the mutant virus was passaged in cell culture. The apparent dispensability of the conserved X domain activity in vitro indicates that coronavirus replicase polyproteins have evolved to include nonessential functions. The biological significance of the novel enzymatic activity in vivo remains to be investigated.

The Reception of Byzantium in European Culture since 1500

Studies on the reception of the classical tradition are an indispensable part of classical studies. Understanding the importance of ancient civilization means also studying how it was used subsequently. This kind of approach is still relatively rare in the field of Byzantine Studies. This volume, which is the result of the range of interests in (mostly) non-English-speaking research communities, takes an important step to filling this gap by investigating the place and dimensions of ‘Byzantium after Byzantium’.
This collection of essays uses the idea of ‘reception-theory’ and expands it to show how European societies after Byzantium have responded to both the reality, and the idea of Byzantine Civilisation. The authors discuss various forms of Byzantine influence in the post-Byzantine world from architecture to literature to music to the place of Byzantium in modern political debates (e.g. in Russia). The intentional focus of the present volume is on those aspects of Byzantine reception less well-known to English-reading audiences, which accounts for the inclusion of Bulgarian, Czech, Polish and Russian perspectives. As a result this book shows that although so-called 'Byzantinism' is a pan-European phenomenon, it is made manifest in local/national versions.
The volume brings together specialists from various countries, mainly Byzantinists, whose works focus not only on Byzantine Studies (that is history, literature and culture of the Byzantine Empire), but also on the influence of Byzantine culture on the world after the Fall of Constantinople.

The Cultures of Popular Culture

Special Issue of the 'Proceedings of the Royal Irish Academy Modern Languages Symposium', reflecting a selection of papers from the Belfast Conference (13th-14th December 2013)

Mineralization of 2,4-dichlorophenol by ectomycorrhizal fungi in axenic culture and in symbiosis with pine

Experiments were conducted to determine if two ectomycorrhizal fungi (Paxillus involutus and Suillus variegatus) could degrade 2,4-dichlorophenol both in axenic liquid culture and during symbiosis with a host tree species Pinus sylvestris. Both fungi readily degraded 2,4- dichlorophenol in batch culture with similar rates of mineralization on a biomass basis. Up to 17% of the 2,4-dichlorophenol was mineralized over a 17 day period. Growth of the fungi in symbiosis with P. sylvestris stimulated greater mineralization than when fungi were grown in absence of the host. S. variegatus was more efficient than P. involutus (in the presence of P. sylveslris) at mineralizing 2,4- dichlorophenol. Mineralization in vermiculite culture was greatly reduced compared to liquid culture. Only 3% of the 2,4-dichlorophenol was mineralized after 13 days in vermiculite culture for the most efficient degrading treatment.