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61.
Cell wall inhibition in a stable streptococcal L-form 总被引:6,自引:0,他引:6
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65.
Allergenic pollen season variations in the past two decades under changing climate in the United States 总被引:1,自引:0,他引:1
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Yong Zhang Leonard Bielory Zhongyuan Mi Ting Cai Alan Robock Panos Georgopoulos 《Global Change Biology》2015,21(4):1581-1589
Many diseases are linked with climate trends and variations. In particular, climate change is expected to alter the spatiotemporal dynamics of allergenic airborne pollen and potentially increase occurrence of allergic airway disease. Understanding the spatiotemporal patterns of changes in pollen season timing and levels is thus important in assessing climate impacts on aerobiology and allergy caused by allergenic airborne pollen. Here, we describe the spatiotemporal patterns of changes in the seasonal timing and levels of allergenic airborne pollen for multiple taxa in different climate regions at a continental scale. The allergenic pollen seasons of representative trees, weeds and grass during the past decade (2001–2010) across the contiguous United States have been observed to start 3.0 [95% Confidence Interval (CI), 1.1–4.9] days earlier on average than in the 1990s (1994–2000). The average peak value and annual total of daily counted airborne pollen have increased by 42.4% (95% CI, 21.9–62.9%) and 46.0% (95% CI, 21.5–70.5%), respectively. Changes of pollen season timing and airborne levels depend on latitude, and are associated with changes of growing degree days, frost free days, and precipitation. These changes are likely due to recent climate change and particularly the enhanced warming and precipitation at higher latitudes in the contiguous United States. 相似文献
66.
Much of our knowledge of the initiation of DNA replication comes from studies in the Gram-negative model organism Escherichia coli. However, the location and structure of the origin of replication within the E. coli genome and the identification and study of the proteins which constitute the E. coli initiation complex suggest that it might not be as universal as once thought. The archetypal low-G+C-content Gram-positive Firmicutes initiate DNA replication via a unique primosomal machinery, quite distinct from that seen in E. coli, and an examination of oriC in the Firmicutes species Bacillus subtilis indicates that it might provide a better model for the ancestral bacterial origin of replication. Therefore, the study of replication initiation in organisms other than E. coli, such as B. subtilis, will greatly advance our knowledge and understanding of these processes as a whole. In this minireview, we highlight the structure-function relationships of the Firmicutes primosomal proteins, discuss the significance of their oriC architecture, and present a model for replication initiation at oriC. 相似文献
67.
Chen L Necela BM Su W Yanagisawa M Anastasiadis PZ Fields AP Thompson EA 《The Journal of biological chemistry》2006,281(34):24575-24587
Peroxisome proliferator-activated receptor gamma (PPARgamma) causes epithelial to mesenchymal transformation (EMT) in intestinal epithelial cells, as evidenced by reorganization of the actin cytoskeleton, acquisition of a polarized, mesenchymal cellular morphology, increased cellular motility, and colony scattering. This response is due to activation of Cdc42, resulting in p21-activated kinase-dependent phosphorylation and activation of MEK1 Ser(298) and activation of ERK1/2. Dominant negative MEK1, MEK2, and ERK2 block PPARgamma-induced EMT, whereas constitutively active MEK1 and MEK2 induce a mesenchymal phenotype similar to that evoked by PPARgamma. PPARgamma also stimulates ERK1/2 phosphorylation in the intestinal epithelium in vivo. PPARgamma induces the p110alpha subunit of phosphoinositide 3-kinase (PI3K), and inhibition of PI3K blocks PPARgamma-dependent phosphorylation of MEK1 Ser(298), activation of ERK1/2, and EMT. We conclude that PPARgamma regulates the motility of intestinal epithelial cells through a mitogen-activated protein kinase cascade that involves PI3K, Cdc42, p21-activated kinase, MEK1, and ERK1/2. Regulation of cellular motility through Rho family GTPases has not been previously reported for nuclear receptors, and elucidation of the mechanism that accounts for the role of PPARgamma in regulating motility of intestinal epithelial cells provides fundamental new insight into the function of this receptor during renewal of the intestinal epithelium. 相似文献
68.
Carneiro MJ Zhang W Ioannou C Scott DJ Allen S Roberts CJ Soultanas P 《Molecular microbiology》2006,60(4):917-924
The Bacillus subtilis DnaD protein is an essential protein that has been implicated in the primosomal step of DNA replication, and recently in global DNA remodelling. Here we show that DnaD consists of two domains with distinct activities; an N-terminal domain (Nd) with oligomerization activity, and a C-terminal domain (Cd) with DNA-binding activity and a second DNA-induced oligomerization activity. Although Cd can bind to DNA and form large nucleoprotein complexes, it does not exhibit global DNA-remodelling activity. The presence of separate Nd does not restore this activity. Our data suggest that the global DNA-remodelling activity of DnaD is the sum of three separate oligomerization and DNA-binding activities residing on two distinct but linked domains. 相似文献
69.
Egg parasitoids are known to use a wide range of chemicals, emitted by plants, host eggs or adults, for host selection. The effect of the sex pheromone components of the lepidopteran olive pests Prays oleae (Lepidoptera: Yponomeutidae) and Palpita unionalis (Lepidoptera: Pyralidae) was studied under laboratory conditions, on the foraging behaviour of the egg parasitoid Trichogramma oleae (Hymenoptera: Trichogrammatidae). The response of T. oleae wasps to ( Z )-7-tetradecenal and ( E )-11-hexadecenal, major sex pheromone components of P. oleae and P. unionalis respectively, depended on the dose of the pheromone used in a Y-tube olfactometer bioassay. ( E )-11-hexadecenal elicited maximum attraction (70%) at a dose of 1 μg, while a dose of 100 μg ( Z )-7-tetradecenal attracted 80% of the tested wasps. ( E )-11-hexadecenyl acetate, the second sex pheromone component of P. unionalis , and the binary blend of ( E )-11-hexadecenyl acetate: ( E )-11-hexadecenal (7:3) were not attractive at these doses. The results of this research are discussed in view that they may be considered as alternatives in the biological control of these pests. 相似文献
70.
A novel interaction between kinesin and p120 modulates p120 localization and function 总被引:10,自引:0,他引:10
Yanagisawa M Kaverina IN Wang A Fujita Y Reynolds AB Anastasiadis PZ 《The Journal of biological chemistry》2004,279(10):9512-9521