Two homologous Nicotiana tabacum genes NtTOM1 and NtTOM3 have been identified. These genes encode polypeptides with amino acid sequence similarity to Arabidopsis thaliana TOM1 and TOM3, which function in parallel to support tobamovirus multiplication. Simultaneous RNA interference against NtTOM1 and NtTOM3 in N. tabacum resulted in nearly complete inhibition of the multiplication of Tomato mosaic virus and other tobamoviruses, but did not affect plant growth or the ability of Cucumber mosaic virus to multiply. As TOM1 and TOM3 homologues are present in a variety of plant species, their inhibition via RNA interference should constitute a useful method for generating tobamovirus-resistant plants.
A total of 111 clinical isolates of Campylobacter jejuni and 10 clinical isolates of Campylobacter coli were characterized by their susceptibility to nine antimicrobial agents and by their plasmid profiles on agarose gel electrophoresis. All of the C. jejuni isolates were susceptible to chloramphenicol, ciprofloxacin, erythromycin, kanamycin, and nalidixic acid, but 55% were tetracycline resistant. In the 10 C. coli isolates, a high prevalence of multiple-antibiotic resistance was noted. Plasmids were found in 82% of the tetracycline-resistant and 15% of the tetracycline-susceptible C. jejuni isolates. Tetracycline resistance in six randomly selected C. jejuni isolates, which contained 50-or 135-kilobase (kb) plasmids, was transferred by conjugation to a Campylobacter fetus subsp. fetus recipient with recovery of a 50-or a 45-kb plasmid from transconjugants. From one multiple-antibiotic-resistant C. coli isolate, resistance to tetracycline, kanamycin, and chloramphenicol was transferred concomitantly with a 58-kb plasmid, pNR9589. Nonconjugative 98-kb plasmids, pNR9131 and pNR9581, from C. coli isolates with resistance to tetracycline, kanamycin, and erythromycin were shown by cloning experiments to code for at least kanamycin resistance. Restriction digests revealed that 50-kb plasmids from tetracycline-resistant C. jejuni isolates were identical, although plasmids from multiple-antibioticresistant C. coli isolates shared partial DNA homology to each other. Cloning of the kanamycin and chloramphenicol resistance genes of pNR9589 into Escherichia coli showed that the two genes are closely linked or clustered. Double-digestion analysis of the fragments encoding the kanamycin resistance of pNR9131, pNR9581, and pNR9589 showed that these three plasmids contain a common fragment related to kanamycin resistance.Campylobacterjejuni is recognized as one of the common causes of acute bacterial enteritis throughout the world (2, 17). More than 200 strains of C. jejuni and a small number of C. coli strains, 60% of which are from children, are isolated every year in Tokyo Metropolitan Toshima General Hospital.Taylor et al. (19, 20) and Tenover et al. (21) demonstrated that tetracycline resistance in C. jejuni is mediated by conjugative R plasmids with a size of 60 kilobases (kb), and more recently, Tenover et al. (22) showed that all tetracycline-resistant C. jejuni harbored R plasmids. Most recently, Taylor (18) mapped the tetracycline resistance plasmid. Studies on plasmid detection in Campylobacter spp.have not yet been carried out in Japan, although clinical and epidemiological studies on Campylobacter spp. have been performed extensively. In the present study, we examined the MICs of nine antimicrobial agents against Campylobacter isolates, the plasmid carriage in these isolates, and the relationship between antimicrobial resistance and plasmid carriage in C. jejuni and C. coli. Moreover, we analyzed three plasmids isolated from multiple-antibiotic-resistant C. coli strains by restriction endonuclease digestion and c...
Crystalline hydrated double carbonates of rare-earth elements and sodium were obtained by adding sodium carbonate solutions to rare-earth chloride solutions. The formula of the precipitates was determined to be LnNa(CO3)2·6H2O (Ln=La, Ce, Nd, Sm, Gd, Dy, and Y). The products have similar X-ray powder diffraction patterns, which were indexed assuming a tetragonal symmetry. The cell parameters of the products were calculated, they decrease linearly with the decrease in the ionic radii of the rare-earth elements.
The factors which influence the crystallization of rare earth carbonates were studied. Crystalline rare earth carbonates were precipitated at various temperatures from aqueous solutions by using sodium carbonate, sodium bicarbonate, trichloroacetic acid, and urea as precipitants. The crystal parameters, compositions, and factors concerning the formations of various carbonates, such as lanthanite-type Ln2(CO3)3·8H2O(Ln=La, Ce), tengeritetype Ln2(CO3)3·nH2O(Ln=Nd, Sm, Gd, Dy, Ho, Er, and Y, n=2–3), monoxocarbonate-type Ln2O(CO3)2·nH2O(Ln=La, Ce, Nd, and Sm, n=1–2) and a hydrated double carbonate of rare earth and sodium (rare earth= La, Ce, Nd, Sm, Gd, Dy, and Y) were determined by chemical analysis and X-ray powder diffractometry.
A plant integral membrane protein TOM1 is involved in the multiplication of Tomato mosaic virus (ToMV). TOM1 interacts with ToMV replication proteins and has been suggested to tether the replication proteins to the membranes where the viral RNA synthesis takes place. We have previously demonstrated that inactivation of TOM1 results in reduced ToMV multiplication. In the present study, we show that overexpression of TOM1 in tobacco also inhibits ToMV propagation. TOM1 overexpression led to a decreased accumulation of the soluble form of the replication proteins and interfered with the ability of the replication protein to suppress RNA silencing. The reduced accumulation of the soluble replication proteins was also observed in a silencing suppressor-defective ToMV mutant. Based on these results, we propose that RNA silencing suppression is executed by the soluble form of the replication proteins and that efficient ToMV multiplication requires balanced accumulation of the soluble and membrane-bound replication proteins.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.