scholarly journals The Binding Characterization of Cry Insecticidal Proteins to the Brush Border Membrane Vesicles of Helicoverpa armigera, Spodoptera exigua, Spodoptera litura and Agrotis ipsilon

2013 ◽  
Vol 12 (9) ◽  
pp. 1598-1605 ◽  
Author(s):  
Qiong LU ◽  
Guang-chun CAO ◽  
Li-li ZHANG ◽  
Ge-mei LIANG ◽  
Xi-wu GAO ◽  
...  
Keyword(s):  
Brush Border ◽  
Spodoptera Litura ◽  
Spodoptera Exigua ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Agrotis Ipsilon ◽  
Insecticidal Proteins ◽  
Helicoverpa Armígera

scholarly journals Characterization of an ATP-driven H+ pump in human placental brush-border membrane vesicles

1992 ◽  
Vol 287 (2) ◽  
pp. 423-430 ◽  
Author(s):  
B J Simon ◽  
P Kulanthaivel ◽  
G Burckhardt ◽  
S Ramamoorthy ◽  
F H Leibach ◽  
...  
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Bafilomycin A1 ◽  
Ph Indicator ◽  
Native Form ◽  
Anion Diffusion ◽  
Partial Activity

The presence of an ATP-driven H+ pump as measured by H+ uptake upon addition of ATP was not demonstrable in human placental brush-border membrane vesicles when used in their native form, owing to their right-side-out orientation. However, the presence of the H+ pump in these membranes became evident when the membrane vesicles were transiently exposed to 1% cholate, with subsequent removal of the detergent to re-form the vesicles. Apparently, cholate pretreatment reoriented the H+ pump from an inward-facing configuration to outward-facing. Consequently, H+ uptake in response to externally added ATP was easily demonstrable in these cholate-pretreated vesicles by using the delta pH indicator Acridine Orange. In addition, bafilomycin A1-sensitive ATPase activity was measurable in cholate-pretreated vesicles, but not in native intact vesicles, indicating reorientation of the H+ pump. The reoriented H+ pump was electrogenic because H+ uptake was stimulated by an inside-negative anion-diffusion potential or when the vesicles were voltage-clamped. ATP supported H+ uptake with an apparent Km of 260 microM. ITP and GTP supported the pump activity partially, whereas CTP and UTP did not. Mg2+ and Mn2+ were the most preferred bivalent cations. Co2+ and Zn2+ showed partial activity, whereas Ca2+ and Ba2+ showed little or no activity. The pump was inhibited by nanomolar concentrations of bafilomycin A1 and micromolar concentrations of N-ethylmaleimide, p-chloromercuribenzenesulphonate, NN-dicyclohexylcarbodi-imide and 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole, but was relatively insensitive to oligomycin, vanadate and NaN3. The inhibition by N-ethylmaleimide was protectable by ATP. It is concluded that human placental brush-border membranes possess an ATP-driven H+ pump and that, on the basis of its characteristics, it belongs to the class of vacuolar (V-type) H+ pumps.

scholarly journals Toxicity, Binding, and Permeability Analyses of FourBacillus thuringiensis Cry1 δ-Endotoxins Using Brush Border Membrane Vesicles of Spodoptera exigua and Spodoptera frugiperda

1999 ◽  
Vol 65 (2) ◽  
pp. 457-464 ◽  
Author(s):  
Ke Luo ◽  
David Banks ◽  
Michael J. Adang
Keyword(s):  
Binding Site ◽  
Spodoptera Frugiperda ◽  
Brush Border ◽  
Spodoptera Exigua ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Binding Assays ◽  
Competition Binding

ABSTRACT The binding and pore formation properties of four Bacillus thuringiensis Cry1 toxins were analyzed by using brush border membrane vesicles from Spodoptera exigua andSpodoptera frugiperda, and the results were compared to the results of toxicity bioassays. Cry1Fa was highly toxic and Cry1Ac was nontoxic to S. exigua and S. frugiperda larvae, while Cry1Ca was highly toxic to S. exigua and weakly toxic to S. frugiperda. In contrast, Cry1Bb was active against S. frugiperda but only marginally active against S. exigua. Bioassays performed with iodinated Cry1Bb, Cry1Fa, and Cry1Ca showed that the effects of iodination on toxin activity were different. The toxicities of I-labeled Cry1Bb and Cry1Fa against Spodoptera species were significantly less than the toxicities of the unlabeled toxins, while Cry1Ca retained its insecticidal activity when it was labeled with 125I. Binding assays showed that iodination prevented Cry1Fa from binding to Spodoptera brush border membrane vesicles. 125I-labeled Cry1Ac, Cry1Bb, and Cry1Ca bound with high-affinities to brush border membrane vesicles fromS. exigua and S. frugiperda. Competition binding experiments performed with heterologous toxins revealed two major binding sites. Cry1Ac and Cry1Fa have a common binding site, and Cry1Bb, Cry1C, and Cry1Fa have a second common binding site. No obvious relationship between dissociation of bound toxins from brush border membrane vesicles and toxicity was detected. Cry1 toxins were also tested for the ability to alter the permeability of membrane vesicles, as measured by a light scattering assay. Cry1 proteins toxic to Spodoptera larvae permeabilized brush border membrane vesicles, but the extent of permeabilization did not necessarily correlate with in vivo toxicity.

Interaction of Allium sativum leaf agglutinin with midgut brush border membrane vesicles proteins and its stability in Helicoverpa armigera

PROTEOMICS ◽  
2010 ◽  
Vol 10 (24) ◽  
pp. 4431-4440 ◽  
Author(s):  
Santosh Kumar Upadhyay ◽  
Manisha Mishra ◽  
Harpal Singh ◽  
Amol Ranjan ◽  
Krishnappa Chandrashekar ◽  
...  
Keyword(s):  
Helicoverpa Armigera ◽  
Brush Border ◽  
Allium Sativum ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Helicoverpa Armígera

scholarly journals Characterization of a sodium-dependent concentrative nucleobase-transport system in guinea-pig kidney cortex brush-border membrane vesicles

1994 ◽  
Vol 303 (3) ◽  
pp. 901-905 ◽  
Author(s):  
D A Griffith ◽  
S M Jarvis
Keyword(s):  
Guinea Pig ◽  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Brush Border Membrane Vesicles ◽  
Hill Coefficient ◽  
Kidney Cortex ◽  
Pig Kidney ◽  
Na Ions

The characteristics of hypoxanthine transport were examined in purified brush-border membrane vesicles isolated from guinea-pig kidney. Hypoxanthine uptake in the vesicles was specifically stimulated by both Na+ and an inside-negative potential, resulting in a transient accumulation of intravesicular hypoxanthine. Na(+)-dependent hypoxanthine influx was saturable (apparent Km 4.4 +/- 2.1 microM, Vmax. 128 +/- 29 pmol/min per mg of protein at 100 mM NaCl and 22 degrees C). Guanine, thymine, 5-fluorouracil and uracil inhibited hypoxanthine uptake (Ki values 1-30 microM), but adenine and the nucleosides inosine and thymidine were without effect. Guanine competitively inhibited Na(+)-dependent hypoxanthine influx, suggesting that it was a substrate for the active nucleobase transporter in guinea-pig renal membrane vesicles. A sigmoidal dependence between hypoxanthine influx and Na+ concentration was obtained (KNa 13 +/- 2 mM; Hill coefficient, h, 2.13 +/- 0.14), suggesting that at least two Na+ ions are transported per hypoxanthine molecule. This system differs from the Na(+)-nucleobase carrier in cultured LLC-PK1 renal cells, which has a stoichiometric coupling ratio of 1:1. These results represent the first demonstration of an active electrogenic nucleobase carrier in renal apical membrane vesicles.

Sign in / Sign up

Export Citation Format

Share Document