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Several crystal (Cry) proteins are known to occur as DNA-protein complexes. However, the role of the DNA associated with the activated toxin in the mechanism of action of the Cry toxin has long been ignored. Here, we focused on the DNA-activated Cry toxin complex. Both forms of the Cry8Ca2 and Cry8Ea1 toxins, i.e., with or without bound DNA, were separately obtained. Size-exclusion chromatography analysis indicated that the Cry8Ca2 toxin-DNA complex has a tight or compact structure. The Cry8Ca2 toxin-DNA complex is more likely to move toward the air/water interface and is more hydrophobic than the toxin without DNA. Competitive binding assays indicated that the Cry8Ca2 and Cry8Ea1 toxins without DNA specifically bind to the midgut of Anomala corpulenta and Holotrichia parallela larvae, respectively. In contrast, the association of DNA with each toxin might result in the nonspecific recognition of the Cry toxin and its target receptor in the insect midgut. The association of the DNA fragment with the Cry8 toxin was shown to protect the Cry protein from digestion by proteases. Based on our results, we propose an additional step in the mechanism of action of the Cry8 toxin and elucidate the function of the associated DNA as well as the importance of the removal of this DNA for the insecticidal activity of the toxin.

Background:Chronic rhinosinusitis is commonly treated by functional endoscopic sinus surgery involving excision of the uncinate process and opening of the osteomeatal complex.Methods:Computational fluid dynamics were used to compare nasal airflow after two different surgical interventions which involved opening the paranasal sinuses, excising the ethmoid sinus, and excising or preserving the uncinate process, in a cadaveric head model. Cross-sectional computed tomography images were obtained before and after the interventions. Imaging data were used to prepare computer simulations, which were used to assess the airflow characteristics of the nasal cavities and paranasal sinuses during inspiration and expiration, before and after intervention.Results:Significantly larger nasal cavity airflow velocity changes were apparent following the uncinate process excising procedure. Nasal cavity airflow distribution remained relatively unchanged following the uncinate process preserving procedure. There was a significantly greater increase in airflow volume following the uncinate process excising procedure, compared with the uncinate process preserving procedure.Conclusion:Preservation of the uncinate process may significantly reduce the alteration of nasal cavity airflow dynamics occurring after functional endoscopic sinus surgery for chronic rhinosinusitis.

Background This study aimed to investigate airflow velocity, trace, distribution, and air pressure, as well as the airflow exchange between the nasal cavity and paranasal sinus in a normal subject using computational fluid dynamics. Methods Fluent software is used to simulate nasal cavity and paranasal sinus structure after CT scanning of a normal adult subject. Airflow velocity, pressure, distribution, and trace lines were calculated by Navier-Stokes equation and numerically visualized. Results Airflow in the common and middle meatus accounted for >50 and 30% of total nasal cavity flow. Flow velocity was maximal in the common meatus, followed by the middle meatus. Flow velocity and flux in each paranasal sinus was extremely low. The flow trace in the inferior and lower part of the common meatus was predominately straight inform. Flow was parabolic in the middle and superior meatus and the middle and upper parts of the common meatus. Air pressure was high at the front end of the inferior and middle turbinate and the uncinate process. There was little pressure difference/flow exchange between inner and outer aspects of the paranasal sinus. Conclusion The major airflow forms are straight (lower common and inferior meatus) and parabolic (middle and upper common meatus and middle superior). Flow force is strongest at the front end of the inferior and middle turbinate and uncinate process. There is very little exchange between the paranasal sinus and the nasal cavity during stable airflow.

In this paper, the effects of free-air CO2 enrichment (FACE) and its interaction with nitrogen supply on the nitrogen content, uptake, allocation, and use efficiency of winter wheat variety Ningmai 9 at its different growth stages were studied in 2001-2003. The results showed that under FACE treatment, the nitrogen content in wheat plant sampled at different growth stages all decreased significantly, with an average decrement of 4.4% to 13.4% compared with the control. The nitrogen accumulation under FACE increased significantly (9.2% -32.3%), and the increasing rate was larger at middle growth stage than at early and late growth stages. Nitrogen fraction was higher in stem, but lower in leaf. As for spike, the accumulation of nitrogen depended on the growth stage. FACE resulted in a significant increase (5.5% -10.3%) of nitrogen use efficiency for biomass production at all growth stages, of nitrogen harvest index (16.3%) at maturing stage, and of nitrogen use efficiency (9.3%) for grain yield. Nitrogen application increased the nitrogen content of wheat plant and its N uptake at all growth stages, decreased the nitrogen use efficiency, but had less effect on the nitrogen allocation in different organs.

A free-air CO2 enrichment (FACE) experiment was conducted in 2001-2003 to study the effects of predicted higher CO2 levels on the dry matter (DM) production and allocation in winter wheat variety Ningmai 9. The results showed that under FACE, the DM production had an increase of 10. 8% , 31. 6% , 40. 5% and 27. 2% during the growth periods from sowing to wintering ( Period 1 ) , wintering to jointing ( Period 2) , jointing to booting ( Period 3) , and booting to heading (Period 4) , respectively, but a decrease of 5. 5% in the period from heading to grain maturity (Period 5). As a result, the final total biomass at maturity was increased by 13. 6%. FACE had no significant effect on leaf area index (LAI) and net assimilation rate (NAR) in Period 1, but made the LAI in Period 2 increased obviously, and the NAR decreased dramatically in Period 3. Under FACE, the proportion of leaf to total above-ground DM decreased, while that of stem (including sheath) to total above-ground DM showed an opposite trend in the whole growth period. The percentage and total amount of soluble sugar and starch in the stem at grain-filling stage were also increased obviously under FACE.