Ісак Мазепа: перші кроки у великій політиці

Досліджується становлення світоглядних позицій та формування політичних поглядів І. Мазепи.Исследуется становление мировоззренческих позиций и формирование политических взглядов И. Мазепы.Formation world outlook positions and formation of political views of I. Mazepa is investigated

Construction and characterization of a bispecific diabody for retargeting T cells to human carcinomas

We describe the construction of a recombinant bispecific antibody fragment in the diabody format with specificity for both the well-established human pancarcinoma associated target antigen EGP2 (epithelial glycoprotein 2, also known as the CO 17-1A antigen or KSA) and the CD3 epsilon chain of human TCR/CD3 complex. The murine anti-ECP2 (MOC31) single chain variable fragment (scFv) and the humanized anti-CD3 (Ucht1v9) scFv were cast into a diabody format (designated Dia5v9) using a short 5 amino acid Gly-Ser linker between immunoglobulin heavy-chain and light-chain variable domains. Purification of the poly-histidine tagged Dia5v9 was achieved from extracts of protease deficient Escerichia coli by IMAC chromatography. The Dia5v9 diabody showed strong binding to both EGP2 and CD3 in transfected cells. The in vitro efficacy of Dia5v9 in mediating tumor cell lysis by interleukin-2 activated human T cells appeared to be similar to that of the hybrid-hybridoma-derived BsF(ab')(2) Bis1 (anti-EGP2/anti-CD3) in a standard 4-hr Cr-51-release assay. This small and partially humanized recombinant bispecific antibody fragment may be valuable for T-cell-based immuno-therapeutical treatment protocols, retargeting activated peripheral blood T lymphocytes to lyse various human carcinomas in vivo. (C) 1998 Wiley-Liss, Inc.</p

Endocytosis of EGFR requires its kinase activity and N-terminal transmembrane dimerization motif

EGFR signaling is attenuated by endocytosis and degradation of receptor-ligand complexes in lysosomes. Endocytosis of EGFR is known to be regulated by multiple post-translational modifications. The observation that prevention of these modifications does not block endocytosis completely, suggests the involvement of other mechanism(s). Recently, receptor clustering has been suggested to induce internalization of multiple types of membrane receptors. However, the mechanism of clustering-induced internalization remains unknown. We have used biparatopic antibody fragments from llama (VHHs) to induce EGFR clustering without stimulating tyrosine kinase activity. Using this approach, we have found an essential role for the N-terminal GG4-like dimerization motif in the transmembrane domain (TMD) for clustering-induced internalization. Moreover, conventional EGF-induced receptor internalization depends exclusively on this TMD dimerization and kinase activity. Mutations in this dimerization motif eventually lead to reduced EGFR degradation and sustained signaling. We propose a novel role for the TMD dimerization motif in the negative-feedback control of EGFR. The widely conserved nature of GG4-like dimerization motifs in transmembrane proteins suggests a general role for these motifs in clustering-induced internalization

Rapid Visualization of Human Tumor Xenografts through Optical Imaging with a Near-infrared Fluorescent Anti-Epidermal Growth Factor Receptor Nanobody

Given that overexpression of the epidermal growth factor receptor (EGFR) is found in many types of human epithelial cancers, noninvasive molecular imaging of this receptor is of great interest. A number of studies have employed monoclonal antibodies as probes; however, their characteristic long half-life in the bloodstream has encouraged the development of smaller probes. In this study, an anti-EGFR nanobody-based probe was developed and tested in comparison with cetuximab for application in optical molecular imaging. To this aim, the anti-EGFR nanobody 7D12 and cetuximab were conjugated to the near-infrared fluorophore IRDye800CW. 7D12-IR allowed the visualization of tumors as early as 30 minutes postinjection, whereas with cetuximab-IR, no signal above background was observed at the tumor site. Quantification of the IR-conjugated proteins in the tumors revealed ≈ 17% of injected dose per gram 2 hours after injection of 7D12-IR, which was significantly higher than the tumor uptake obtained 24 hours after injection of cetuximab-IR. This difference is associated with the superior penetration and distribution of 7D12-IR within the tumor. These results demonstrate that this anti-EGFR nanobody conjugated to the NIR fluorophore has excellent properties for rapid preclinical optical imaging, which holds promise for its future use as a complementary diagnostic tool in humans

Subalpine forest development following a blowdown in the Mount Zirkel Wilderness, Colorado

We documented the occurrence of a 1934 blowdown in a subalpine forest in northwestern Colorado, USA. Prior to the blowdown, the stand was dominated by old-growth Picea engelmannii - Abies lasiocarpa forests. Although blowdowns are believed to trigger outbreaks of Dendroctonus rufipennis (spruce beetle), we found no detectable increase in beetle caused mortality. Forest recovery was by both release of the previously suppressed regeneration and by new seedling establishment. Both recovery pathways were dominated by Abies. The blowdown thus caused a shift in species dominance from Picea to Abies; 65 yr after the blowdown, the fallen logs and tip up mounds continue to provide favourable habitat for seedling establishment of both species. The present study shows that the legacy of blowdowns can influence forest dynamics for decades following the disturbance event

Flora vascular da Reserva Biológica da Represa do Grama, Minas Gerais, e sua relação florística com outras florestas do sudeste brasileiro

Este trabalho apresenta o levantamento florístico das plantas vasculares da Reserva Biológica da Represa do Grama, um remanescente de floresta estacional semidecidual do Domínio Atlântico, situado no município de Descoberto, Minas Gerais. Foram realizadas coletas quinzenais de material fértil entre agosto de 1999 e dezembro de 2004. Além do levantamento, fez-se a comparação da composição florística através de análises multivariadas de agrupamento com outras nove áreas (3 de floresta estacional e 6 de ombrófila), cujos levantamentos florísticos de angiospermas tiveram abordagem semelhante. Cada análise foi processada para o conjunto total das espécies e para oito hábitos: árvores (incluindo arvoretas), arbustos, trepadeiras (lenhosas e herbáceas), ervas terrícolas, ervas saxícolas, epífitas, hemiepífitas e parasitas. Na ReBio do Grama foram registradas 644 espécies de angiospermas, distribuídas em 370 gêneros e 100 famílias. Licófitas e samambaias estão representadas por 64 espécies, distribuídas em 37 gêneros e 16 famílias. Seis espécies de angiospermas foram descritas como novas para a ciência. Fabaceae (55 spp.) foi a família com maior riqueza específica, seguida de Rubiaceae (50 spp.), Melastomataceae (28 spp.), Bignoniaceae e Orchidaceae (27 spp. cada) e Myrtaceae (25 spp.). As análises multivariadas sugeriram que os gradientes longitudinais, latitudinais e altitudinais interferem de formas distintas sobre os padrões de riqueza dos diferentes hábitos. O número reduzido de espécies compartilhadas entre as áreas, associado com alta riqueza regionalizada de alguns hábitos demonstra a importância da conservação de fragmentos nas diferentes regiões geográficas da Floresta Atlântica como estratégia para maximizar a conservação da diversidade existente neste domínio fitogeográfico