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971.
A simple rapid technic is described for demonstrating mast cells in mouse skin. The procedure requires about 60 minutes from time of specimen removal until permanent mounting. The steps comprise: (1) stretch-mounting of skin on a cardboard frame; (2) fixing and dehydrating in absolute ethanol for 15 minutes; (3) xylene washing for 10 minutes; (4) absolute ethanol washing for 10-15 minutes; (5) 3-4 minutes in a 0.1% aqueous solution of methylene blue; (6) dehydrating and differentiating in absolute ethanol; (7) clearing in xylene; (8) trimming and mounting. Cell counts may be made immediately, as well as high dry and oil immersion study of cytological detail of mast cells. 相似文献
972.
973.
Nowak Agnieszka Pacek Gabriela Mrozik Agnieszka 《Reviews in Environmental Science and Biotechnology》2020,19(2):337-354
Reviews in Environmental Science and Bio/Technology - Iodinated X-ray contrast media (ICM) such as diatrizoate, iohexol, iomeprol, iopamidol, and iopromide are commonly used in medical imaging for... 相似文献
974.
975.
Jessica M. Cable Kiona Ogle Richard W. Lucas Travis E. Huxman Michael E. Loik Stanley D. Smith David T. Tissue Brent E. Ewers Elise Pendall Jeffrey M. Welker Therese N. Charlet Meagan Cleary Alden Griffith Robert S. Nowak Matthew Rogers Heidi Steltzer Patrick F. Sullivan Natasja C. van Gestel 《Biogeochemistry》2011,103(1-3):71-90
The temperature response of soil respiration in deserts is not well quantified. We evaluated the response of respiration to temperatures spanning 67°C from seven deserts across North America and Greenland. Deserts have similar respiration rates in dry soil at 20°C, and as expected, respiration rates are greater under wet conditions, rivaling rates observed for more mesic systems. However, deserts differ in their respiration rates under wet soil at 20°C and in the strength of the effect of current and antecedent soil moisture on the sensitivity and magnitude of respiration. Respiration increases with temperature below 30°C but declines for temperatures exceeding 35°C. Hot deserts have lower temperature sensitivity than cold deserts, and insensitive or negative temperature sensitivities were predicted under certain moisture conditions that differed among deserts. These results have implications for large-scale modeling efforts because we highlight the unique behavior of desert soil respiration relative to other systems. These behaviors include variable temperature responses and the importance of antecedent moisture conditions for soil respiration. 相似文献
976.
Jan Sauer Sami Domisch Carsten Nowak Peter Haase 《Biodiversity and Conservation》2011,20(13):3133-3146
Global climate change (GCC) is expected to lead to massive loss of global biodiversity in the alpine regions of mountain ranges.
Studies on the potential effects of GCC on low mountain areas remain sparse, however, despite the high conservation value
of these areas as biodiversity refugia. We chose a species distribution modeling approach to assess potential GCC impacts
on the future distributions of montane freshwater invertebrates under two different greenhouse gas scenarios and three averaged
general circulation models. For this, ensemble models consisting of six algorithms [generalized linear model (GLM), generalized
boosted model (GBM), generalized additive model (GAM), classification tree analysis (CTA), artificial neural networks (ANN),
and multivariate adaptive regression splines (MARS)] were applied to project areas of 23 cold-stenothermic aquatic insects
from montane regions of Central Europe. We found an average loss of 70–80% of the potential distribution for the study species
until 2080, depending on the underlying Intergovernmental Panel on Climate Change scenario. Species distribution ranges below
1000 m above sea level were found to decrease by up to ~96% according to the severest greenhouse gas emission scenario. While
the Alps remain the single main refugium under the A2a greenhouse gas emission scenario, the more moderate climate scenario
B2a shows fragmented potential persistence of montane insects in some low mountain ranges. The results show that montane freshwater
assemblages in low mountain ranges are particularly threatened by ongoing GCC. As vertical dispersal is limited by elevational
restriction, low mountain ranges may act as summit traps under GCC. We thus propose that GCC will lead to the extinction of
several species and unique genetic lineages of postglacial relict species, resulting in a significant decline in Central European
fauna. 相似文献
977.
Forty years ago, it was proposed that during embryonic development and organogenesis, morphogen gradients provide positional information to the individual cells within a tissue leading to specific fate decisions. Recently, much insight has been gained into how such morphogen gradients are formed and maintained; however, which cellular mechanisms govern their interpretation within target tissues remains debated. Here we used in vivo fluorescence correlation spectroscopy and automated image analysis to assess the role of endocytic sorting dynamics on fibroblast growth factor 8 (Fgf8) morphogen gradient interpretation. By interfering with the function of the ubiquitin ligase Cbl, we found an expanded range of Fgf target gene expression and a delay of Fgf8 lysosomal transport. However, the extracellular Fgf8 morphogen gradient remained unchanged, indicating that the observed signalling changes are due to altered gradient interpretation. We propose that regulation of morphogen signalling activity through endocytic sorting allows fast feedback-induced changes in gradient interpretation during the establishment of complex patterns. 相似文献
978.
Self-incompatibility (SI) is widespread in the angiosperms, but identifying the biochemical components of SI mechanisms has proven to be difficult in most lineages. Coffea (coffee; Rubiaceae) is a genus of old-world tropical understory trees in which the vast majority of diploid species utilize a mechanism of gametophytic self-incompatibility (GSI). The S-RNase GSI system was one of the first SI mechanisms to be biochemically characterized, and likely represents the ancestral Eudicot condition as evidenced by its functional characterization in both asterid (Solanaceae, Plantaginaceae) and rosid (Rosaceae) lineages. The S-RNase GSI mechanism employs the activity of class III RNase T2 proteins to terminate the growth of "self" pollen tubes. Here, we investigate the mechanism of Coffea GSI and specifically examine the potential for homology to S-RNase GSI by sequencing class III RNase T2 genes in populations of 14 African and Madagascan Coffea species and the closely related self-compatible species Psilanthus ebracteolatus. Phylogenetic analyses of these sequences aligned to a diverse sample of plant RNase T2 genes show that the Coffea genome contains at least three class III RNase T2 genes. Patterns of tissue-specific gene expression identify one of these RNase T2 genes as the putative Coffea S-RNase gene. We show that populations of SI Coffea are remarkably polymorphic for putative S-RNase alleles, and exhibit a persistent pattern of trans-specific polymorphism characteristic of all S-RNase genes previously isolated from GSI Eudicot lineages. We thus conclude that Coffea GSI is most likely homologous to the classic Eudicot S-RNase system, which was retained since the divergence of the Rubiaceae lineage from an ancient SI Eudicot ancestor, nearly 90 million years ago. 相似文献
979.
Roberta B. Nowak Robert S. Fischer Rebecca K. Zoltoski Jerome R. Kuszak Velia M. Fowler 《The Journal of cell biology》2009,186(6):915-928
Hexagonal packing geometry is a hallmark of close-packed epithelial cells in metazoans. Here, we used fiber cells of the vertebrate eye lens as a model system to determine how the membrane skeleton controls hexagonal packing of post-mitotic cells. The membrane skeleton consists of spectrin tetramers linked to actin filaments (F-actin), which are capped by tropomodulin1 (Tmod1) and stabilized by tropomyosin (TM). In mouse lenses lacking Tmod1, initial fiber cell morphogenesis is normal, but fiber cell hexagonal shapes and packing geometry are not maintained as fiber cells mature. Absence of Tmod1 leads to decreased γTM levels, loss of F-actin from membranes, and disrupted distribution of β2-spectrin along fiber cell membranes. Regular interlocking membrane protrusions on fiber cells are replaced by irregularly spaced and misshapen protrusions. We conclude that Tmod1 and γTM regulation of F-actin stability on fiber cell membranes is critical for the long-range connectivity of the spectrin–actin network, which functions to maintain regular fiber cell hexagonal morphology and packing geometry. 相似文献
980.
Izabela Nowak Maria Magott-Procelewska Agnieszka Kowal Maciej Miazga Marta Wagner Wanda Niepiek?o-Miniewska Ma?gorzata Kamińska Andrzej Wi?niewski Edyta Majorczyk Marian Klinger Wioleta ?uszczek Andrzej Pawlik Rafa? P?oski Ewa Barcz David Senitzer Piotr Ku?nierczyk 《PloS one》2012,7(9)