Interactions among oscillatory pathways in NF-kappa B signaling

Background  

Sustained stimulation with tumour necrosis factor alpha (TNF-alpha) induces substantial oscillations—observed at both the single cell and population levels—in the nuclear factor kappa B (NF-kappa B) system. Although the mechanism has not yet been elucidated fully, a core system has been identified consisting of a negative feedback loop involving NF-kappa B (RelA:p50 hetero-dimer) and its inhibitor I-kappa B-alpha. Many authors have suggested that this core oscillator should couple to other oscillatory pathways.     

Cotton boll age influences feeding preference by brown stink bug (Heteroptera: Pentatomidae)

Cotton plants were infested with brown stink bug, Euschistus servus (Say), to define cotton boll age classes (based on heat unit accumulation beyond anthesis) that are most frequently injured during each of the initial 5 wk of flowering. Bolls from each week were grouped into discrete age classes and evaluated for the presence of stink bug injury. Brown stink bug injured significantly more bolls of age class B (approximately 165-336 heat units), age class C (approximately 330-504 heat units), and age class D (approximately 495-672 heat units) during the initial 3 wk in both years and in week 5 in 2002 compared with other boll ages. Generally, the frequency of injured bolls was lowest in age class A (< or = 168 heat units) during these periods. The preference by brown stink bug for boll age classes B, C, and D within a week was similar when ages were combined across all 5 wk. Based on these data, bolls that have accumulated 165.2 through 672 heat units beyond anthesis (approximately 7-27-d-old) are more frequently injured by brown stink bug when a range of boll ages are available. The boll ages in our studies corresponded to a boll diameter of 1.161-3.586 cm with a mid-range of 2.375 cm. A general protocol for initiating treatments against stink bugs is to sample bolls for evidence of injury as an indicator of presence of infestations in cotton. Sampling bolls within a defined range, which is most likely to be injured, should improve the precision of this method in detecting economic stink bug infestations in cotton.     

Comparative susceptibility of European corn borer, southwestern corn borer, and sugarcane borer (Lepidoptera: Crambidae) to Cry1Ab protein in a commercial Bacillus thuringiensis corn hybrid

One field strain each of the European corn borer, Ostrinia nubilalis (Hübner); southwestern corn borer, Diatraea grandiosella Dyar; and sugarcane borer, Diatraea saccharalis (F.); were collected from cornfields in northeastern Louisiana. Susceptibilities of the field strain and a corresponding laboratory strain of the three borer species to Cry1Ab protein in DK69-70 Bacillus thuringiensis (Bt) corn hybrid were determined by exposing neonates to intact leaf tissues from whorl stage plants or by feeding neonates or third instars on a meridic diet treated with different concentrations of Cry1lAb protein extracted from Bt corn leaves. Mortality and growth of larvae were evaluated after 2 and 4 d posttreatment in the bioassays by using intact leaf tissues or after 7 d in the bioassays by using diet incorporating Cry1Ab protein. D. saccharalis was the least susceptible species to Cry1Ab protein among the three species, followed by D. grandiosella, whereas O. nubilalis was most susceptible. The 2-d mortality of D. saccharalis neonates on intact Bt leaf tissues was lower than that of O. nubilalis and D. grandiosella. All neonates of O. nubilalis were killed on the diet treated with Cry1Ab protein at 0.5 and 1 mg/kg. The mortality of D. grandiosella was > 75% at 1 mg/kg, but it was < 6% for D. saccharalis at 1 mg/kg. The LC50 values of D. saccharalis were 3- and 11-fold higher than those of D. grandiosella and O. nubilalis, respectively. The LC90 values of D. saccharalis were 8- and 32-fold higher than those of D. grandiosella and O. nubilalis, respectively. Larval growth of the three species on Cry1Ab-treated diet was inhibited, but the inhibition was greater for O. nubilalis and D. grandiosella than for D. saccharalis. The lower susceptibility of D. saccharalis to Cry1Ab protein suggests that it is necessary to verify if a high-dose Bt corn for O. nubilalis and D. grandiosella is also a high dose for D. saccharalis.     

Dynamic reorganization of Eg5 in the mammalian spindle throughout mitosis requires dynein and TPX2

Kinesin-5 is an essential mitotic motor. However, how its spatial-temporal distribution is regulated in mitosis remains poorly understood. We expressed localization and affinity purification-tagged Eg5 from a mouse bacterial artificial chromosome (this construct was called mEg5) and found its distribution to be tightly regulated throughout mitosis. Fluorescence recovery after photobleaching analysis showed rapid Eg5 turnover throughout mitosis, which cannot be accounted for by microtubule turnover. Total internal reflection fluorescence microscopy and high-resolution, single-particle tracking revealed that mEg5 punctae on both astral and midzone microtubules rapidly bind and unbind. mEg5 punctae on midzone microtubules moved transiently both toward and away from spindle poles. In contrast, mEg5 punctae on astral microtubules moved transiently toward microtubule minus ends during early mitosis but switched to plus end-directed motion during anaphase. These observations explain the poleward accumulation of Eg5 in early mitosis and its redistribution in anaphase. Inhibition of dynein blocked mEg5 movement on astral microtubules, whereas depletion of the Eg5-binding protein TPX2 resulted in plus end-directed mEg5 movement. However, motion of Eg5 on midzone microtubules was not altered. Our results reveal differential and precise spatial and temporal regulation of Eg5 in the spindle mediated by dynein and TPX2.     

Public History,Private Memory: Notes from the Ethnography of Colonial Williamsburg,Virginia, USA

Colonial Williamsburg, and U.S. history museums generally, claim to transform public history into collective memory. That is, they convey an objective documented history to the public who, absorbing that history, acquires an appropriate collective or national memory. We argue that the emphasis on consumer (visitor) experience at such museums collapses the distance between the reconstructed past (the museum's history lesson) and the visitor's touristic or familial experience at the site. Visitors indeed remember their visits to Colonial Williamsburg, but their specific memories would seem to have little to contribute to any 'collective memory' of a 'national history.'     

Adsorption of ethylenediaminetetraacetic dianhydride modified oxalate decarboxylase on calcium oxalate

We used ethylenediaminetetraacetic acid dianhydride (EDTAD) to modify oxalate decarboxylase (OXDC) to improve its adsorption on calcium oxalate stones. The modified sites were identified by Ultra performance liquid chromatography-mass spectrometry (UPLC-MS) and the adsorption mechanism of the EDTAD-modified OXDC on calcium oxalate (CaOx) was investigated. We investigated adsorption time, initial enzyme concentration, temperature and solution pH on the adsorption process. Data were analyzed using kinetics, thermodynamics and isotherm adsorption models. UPLC-MS showed that EDTAD was attached to OXDC covalently and suggested that the chemical modification occurred at both the free amino of the side chain and the α-NH₂ of the peptide. The adsorption capacity of the EDTAD-OXDC on calcium oxalate was 53.37% greater than that of OXDC at the initial enzyme concentration of 5 mg/ml, pH = 7.0, at 37° C. The modified enzyme (EDTAD-OXDC) demonstrated improved oxalate degradation activity at pH 4.5?6.0. Kinetic data fitting analysis suggested a pseudo second order kinetic model. Estimates of the thermodynamic parameters including ΔG⁰, ΔH⁰ and ΔS⁰ of the adsorption process showed it to be feasible, spontaneous and endothermic. Isotherm data fitting analysis indicated that the adsorption process is reduced to monolayer adsorption at a low enzyme concentration and to multilayer adsorption at a high enzyme concentration. It may be possible to apply OXDC to degradation of calcium oxalate stones.     

The forgotten prey of an iconic predator: a review of interactions between grey wolves Canis lupus and beavers Castor spp.

相似文献   

Mitochondrial DNA structure and colony expansion dynamics of New Zealand fur seals (Arctocephalus forsteri) around Banks Peninsula

New Zealand fur seals are one of many pinniped species that survived the commercial sealing of the eighteenth and nineteenth centuries in dangerously low numbers. After the enforcement of a series of protection measures in the early twentieth century, New Zealand fur seals began to recover from the brink of extinction. We examined the New Zealand fur seal populations of Banks Peninsula, South Island, New Zealand using the mitochondrial DNA control region. We identified a panmictic population structure around Banks Peninsula. The most abundant haplotype in the area showed a slight significant aggregated structure. The Horseshoe Bay colony showed the least number of shared haplotypes with other colonies, suggesting a different origin of re-colonisation of this specific colony. The effective population size of the New Zealand fur seal population at Banks Peninsula was estimated at approximately 2500 individuals. The exponential population growth rate parameter for the area was 35, which corresponds to an expanding population. In general, samples from adjacent colonies shared 4.4 haplotypes while samples collected from colonies separated by between five and eight bays shared 1.9 haplotypes. The genetic data support the spill-over dynamics of colony expansion already suggested for this species. Approximate Bayesian computations analysis suggests re-colonisation of the area from two main clades identified across New Zealand with a most likely admixture coefficient of 0.41 to form the Banks Peninsula population. Approximate Bayesian computations analysis estimated a founder population size of approximately 372 breeding individuals for the area, which then rapidly increased in size with successive waves of external recruitment. The population of fur seals in the area is probably in the late phase of maturity in the colony expansion dynamic.