Recent H3N2 Influenza Virus Clinical Isolates Rapidly Acquire Hemagglutinin or Neuraminidase Mutations When Propagated for Antigenic Analyses

Prior to serological testing, influenza viruses are typically propagated in eggs or cell culture. Recent human H3N2 strains bind to cells with low avidity. Here, we isolated nine primary H3N2 viral isolates from respiratory secretions of children. Upon propagation in vitro, five of these isolates acquired hemagglutinin or neuraminidase mutations that increased virus binding to cell surfaces. These mutations can potentially confound serological assays commonly used to identify antigenically novel influenza viruses.     

Revision of Eurudagnostus Lermontova (Agnostida, ?Trilobita)

The validity of Eurudagnostus Lermontova, 1951 was confirmed by reexamination of the collection from the Boshe-Kul’ core. The diagnoses of genera of Agnostidae were reviewed, and Eurudagnostus falls well within the concept of the family Agnostidae. The diagnostic features of Eurudagnostus include a delicate border furrows, the transglabellar furrow bent posteriad or straight, short pygidial axis, incomplete transaxial F1, absent or very poorly developed median preglabellar furrow, and absent lanceolate field on the posteroaxis. Following revision the genus comprises 12 valid species, including some species and varieties previously assigned to other genera. ?Eurudagnostus brevispinus Lermontova, 1951 is synonymized with E. chiushuensis (Kobayashi, 1931). Two species, E. chiushuensis and ?E. intermedius (Palmer, 1968) appeared to have inter-continental distribution in the Cambrian-Ordovician beds, and E. mutabilis (Ergaliev, 1980) is also more widely distributed than previously recognized.     

Posttranslational Regulation of Human DNA Polymerase ι

Human DNA polymerases (pols) η and ι are Y-family DNA polymerase paralogs that facilitate translesion synthesis past damaged DNA. Both polη and polι can be monoubiquitinated in vivo. Polη has been shown to be ubiquitinated at one primary site. When this site is unavailable, three nearby lysines may become ubiquitinated. In contrast, mass spectrometry analysis of monoubiquitinated polι revealed that it is ubiquitinated at over 27 unique sites. Many of these sites are localized in different functional domains of the protein, including the catalytic polymerase domain, the proliferating cell nuclear antigen-interacting region, the Rev1-interacting region, and its ubiquitin binding motifs UBM1 and UBM2. Polι monoubiquitination remains unchanged after cells are exposed to DNA-damaging agents such as UV light (generating UV photoproducts), ethyl methanesulfonate (generating alkylation damage), mitomycin C (generating interstrand cross-links), or potassium bromate (generating direct oxidative DNA damage). However, when exposed to naphthoquinones, such as menadione and plumbagin, which cause indirect oxidative damage through mitochondrial dysfunction, polι becomes transiently polyubiquitinated via Lys¹¹- and Lys⁴⁸-linked chains of ubiquitin and subsequently targeted for degradation. Polyubiquitination does not occur as a direct result of the perturbation of the redox cycle as no polyubiquitination was observed after treatment with rotenone or antimycin A, which both inhibit mitochondrial electron transport. Interestingly, polyubiquitination was observed after the inhibition of the lysine acetyltransferase KATB3/p300. We hypothesize that the formation of polyubiquitination chains attached to polι occurs via the interplay between lysine acetylation and ubiquitination of ubiquitin itself at Lys¹¹ and Lys⁴⁸ rather than oxidative damage per se.