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51.
Tomáš Trnka Miloslav Černý Anna Ya. Shmyrina Alexander S. Shashkov Alexander F. Sviridov Oleg S. Chizhov 《Carbohydrate research》1979,76(1):39-44
13C-N.m.r. spectra of all possible 1,6:2,3- and 1,6:3,4-dianhydro-β-D-hexo-pyranoses and their O-acetyl and deoxy derivatives are presented. Relations between chemical shifts of certain carbon atoms and the structure of the dianhydrides are outlined, and their application in structural analysis is discussed. Inversion of configuration of the oxirane ring from the endo to the exo position is associated with typical upfield-shifts for oxirane-ring carbon atoms C-2 or C-4, respectively. Possible inter-relationships between 13C-chemical shifts and steric and polar interactions in the dianhydro derivatives are discussed. 相似文献
52.
M. Proštenik I. Burcar A. Častek Č. Ćosović J. Golem Z. Jandrić K. Kljaić V. Ondrušek 《Chemistry and physics of lipids》1978,22(2):97-103
Total fatty acids derived from 12 species of mushrooms were separated into fatty acid and 2-hydroxy fatty acid fractions (FA and HFA), and analyzed quantitatively. The HFA content varied from 0 to 22% of total fatty acids. The major fatty acids were 16:0, 18:0, 18:1, 18:2, and the major 2-hydroxy fatty acids were h16:0, h18:0, h22:0, h24:0. The predominant HFA in the mushrooms investigated had chain-lengths greater than 20 C-atoms, and were derived from sphingolipids — ceramides and cerebrosides. 相似文献
53.
54.
Thymectomized, lethally irradiated mice reconstituted with syngeneic bone marrow cells are tolerant to xenogeneic Yoshida ascites sarcoma (YAS). The tolerance was abolished by an injection of syngeneic normal spleen, thymus, or lymph node cells given simultaneously with YAS. Allogeneic and semiallogeneic spleen cells were ineffective. The YAS-rejecting mice produced specific anti-tumor antibodies. The serum of these mice transferred to tolerant T-cell-deficient mice protected the latter from inoculated YAS cells. These serum-protected mice were not able to resist the reinoculum of the tumor cells as the mice restored with lymphoid cells did. The latter mice rejected the YAS at the time when donor cells were practically absent in their lymphoid tissue. The low effective ratio of injected syngeneic lymphoid to tumor cells, efficiency of injected thymus cells, and other data led to the conclusion that transferred lymphoid cells did not act directly on tumor cells but through cooperation with host lymphoid cells. The cooperation of donor T- and host B-lymphocytes enabled the activation of the latter, and YAS cells were rejected. 相似文献
55.
The protective effect of pig immune colostrum, serum and immunoglobulins IgG, IgM and IgA against the enterotoxic strain ofEscherichia coli O55, was studied in newborn germfree piglets. This strain produced accumulation of fluid and dilatation of intestine when
injected into the ligated ileal segment of germfree piglets, which is considered to be the typical effect of enterotoxins.
Erosion of the intestinal epithelium and penetration of bacteria into the submucosa were also observed. Immune serum, colostrum
and all the immunoglobulin classes used produced a local protective effect, IgA being most effective. The mechanism of protection
conferred by these immunoglobulins is discussed with respect to the possible pathogenic action of enterotoxicEscherichia coli O55 in the intestinal tract of immunologically virgin germfree piglets. 相似文献
56.
Dr. L. Čelakovský 《Plant Systematics and Evolution》1890,40(8):315-319
Ohne ZusammenfassungDas Referat bezieht sich auf den Zeitraum vom 1. Jänner bis 1. Juni 1890. 相似文献
57.
The effect of a mutation in a gene located near thepro marker and determining the normal colony formation and the cell density inEscherichia coli has been analyzed. Thencf mutation has no effect on the permeability of the cell to actinomycin D. On the other hand, a higher level of ATP and a defect
in the accumulation of the reserve material in the mutant cell were detected. 相似文献
58.
Tomáš Fiala Jaroslav Holuša Jiří Procházka Lukáš Čížek Marek Dzurenko Jiří Foit Juraj Galko Josef Kašák Jan Kulfan Ferenc Lakatos Oto Nakládal Jiří Schlaghamerský Michal Svatoš Jiří Trombik Petr Zábranský Peter Zach Emanuel Kula 《Journal of Applied Entomology》2020,144(6):423-433
Invasive organisms represent great threats to ecosystems and great challenges to forest management. In Europe, the black timber bark beetle (Xylosandrus germanus) is an invasive secondary pest that mostly attacks the logs of felled trees. We showed the invasion history for Europe and using many local surveys, we summarize the current distribution and other available information on X. germanus in the Czech Republic. We report that this species is distributed from the lowlands to the mountains in the Czech Republic; it is widespread in the eastern half of the country, where it is more abundant in the warmer south and southeast areas than in the cooler areas. Most (78%) of the known localities are at elevation below 400 m a.s.l. Although an ice storm greatly increased X. germanus abundance near the border with Austria, its high abundance did not result in damage to standing trees. Presence of X. germanus in the Czech Republic for over 10 years has not led to heavy tree infestation. 相似文献
59.
Matić Ivana Z. Ergün Sercan Đorđić Crnogorac Marija Misir Sema Aliyazicioğlu Yüksel Damjanović Ana Džudžević-Čančar Hurija Stanojković Tatjana Konanç Kalbiye Petrović Nina 《Cytotechnology》2021,73(3):373-389
Cytotechnology - Six extracts were obtained from plant species Hypericum perforatum L., collected at Samsun in Turkey. The aim of this study was to examine the mechanisms of the anticancer activity... 相似文献
60.
Zuzana Chumová Eliška Záveská Petra Hloušková Jan Ponert Philipp-André Schmidt Martin Čertner Terezie Mandáková Pavel Trávníček 《The Plant journal : for cell and molecular biology》2021,107(2):511-524
Although the evolutionary drivers of genome size change are known, the general patterns and mechanisms of plant genome size evolution are yet to be established. Here we aim to assess the relative importance of proliferation of repetitive DNA, chromosomal variation (including polyploidy), and the type of endoreplication for genome size evolution of the Pleurothallidinae, the most species-rich orchid lineage. Phylogenetic relationships between 341 Pleurothallidinae representatives were refined using a target enrichment hybrid capture combined with high-throughput sequencing approach. Genome size and the type of endoreplication were assessed using flow cytometry supplemented with karyological analysis and low-coverage Illumina sequencing for repeatome analysis on a subset of samples. Data were analyzed using phylogeny-based models. Genome size diversity (0.2–5.1 Gbp) was mostly independent of profound chromosome count variation (2n = 12–90) but tightly linked with the overall content of repetitive DNA elements. Species with partial endoreplication (PE) had significantly greater genome sizes, and genomic repeat content was tightly correlated with the size of the non-endoreplicated part of the genome. In PE species, repetitive DNA is preferentially accumulated in the non-endoreplicated parts of their genomes. Our results demonstrate that proliferation of repetitive DNA elements and PE together shape the patterns of genome size diversity in orchids. 相似文献