NaCl-Induced Changes of Ion Fluxes in Roots of Transgenic Bacillus thuringiensis (Bt) Cotton (Gossypium hirsutum L.)

Bacillus thuringiensis （Bt） cotton is grown worldwide, including in saline soils, but the effect of salinity on ion fluxes of Bt cotton remains unknown. Responses of two transgenic Bt cotton genotypes （SGK321 and 29317） and their corresponding receptors, Shiyuan 321 （SY321） and Jihe 321 （J321）, to 150 mmol L-1 NaCl stress were studied in a growth chamber. The root dry weight of SGK321 and 29317 under NaCl treatment was decreased by 30 and 31%, respectively. However, their corresponding receptor cultivars SY321 and J321 were less affected （19 and 24%, respectively）. The root length and surface area of the Bt cultivars were significantly decreased relative to their receptors under salt stress. NaCl treatment significantly increased CrylAc mRNA transcript levels in SGK321 and 29317 but did not affect Bt protein content in leaves or roots of either cultivar at 1 and 7 d after NaCl treatment. Fluxes of Na^＋, K^＋, and H^＋ in roots were investigated using the scanning ion-selective electrode technique. Both mean K^＋ efflux rate and transient K^＋ efflux of the Bt cultivars increased four-fold compared to their corresponding receptors when exposed to salinity stress. There were no significant differences in Na^＋ efflux between Bt and non-Bt cottons. Furthermore, the Na^＋ contents in roots and leaves of all genotypes dramatically increased under salt stress, whereas K^＋ contents decreased. Our results suggested that Bt cotton cultivars are more sensitive to salt stress than their receptor genotypes.

MXene:An efficient hemoperfusion sorbent for the removal of uremic toxins

MXene,a family of two-dimensional(2D)transition metal carbides and nitrides have attracted extensive interests for many biochemical applications,including tumour elimination,biosensors,and magnetic resonance imaging(MRI).In this article,we firstly discovered that Ti3C2Tx MXene exhibited a highly efficient adsorption capability as hemoperfusion absorbent towards middle-molecular mass and protein bound uremic toxins in the end stage of renal disease(ESRD)treatment.Molecular scale investigations reveal that the high efficiency of MXene for the removal of uremic toxins could be attributed to synergistic effects of physical/chemical adsorption,electrostatic interaction surface of 2D MXene,and transformation of protein secondary structure.2D MXene materials could be used as a new hemoperfusion sorbent with ultrahigh efficiency for removing uremic toxins during the treatment of kidney disease.

Adsorption and Desorption of Cry1Ab Proteins on Differently Textured Paddy Soils

In recent years, selected cry genes from Bacillus thuringiensis（Bt） encoding the production of Cry proteins（Bt toxins） have been engineered into crop plants（Bt-crops）. Through the cultivation of Bt crops and the application of Bt pesticides, Cry proteins could be introduced into arable soils. The interaction between the proteins and soils was analyzed in this study to investigate the affinity of Cry proteins in paddy soil ecosystems. Four Paddy soils were selected to represent different soil textures. Cry proteins were spiked in soils, and the amount of protein adsorbed was measured over 24 h. Desorption of Cry1Ab proteins from paddy soils was performed by washing with sterile Milli-Q water（H_2O_（MQ））, and subsequently extracted with an extraction buffer. The paddy soils had a strong affinity for Cry1Ab proteins. Most of the Cry1Ab proteins added（＆gt; 98%） were rapidly adsorbed on the paddy soils tested. More Cry1Ab proteins were adsorbed on non-sterile soils than on sterile soils. Less than 2% of the adsorbed Cry1Ab proteins were desorbed using H2 OMQ, while a considerable proportion of the adsorbed proteins could be desorbed with the buffer, ranging from 20% to 40%.The amount of proteins desorbed increased with the increases in the initial amount of Cry1Ab proteins added to the paddy soils. The concentration of Cry1Ab proteins desorbed from the paddy soils was higher for sterile soils than non-sterile ones. Our results indicate that Bt toxins released via the cultivation of Bt crops, the application of Bt pesticides can be adsorbed on paddy soils, and soil texture could impose an impact on the adsorption capability.