scholarly journals Identification of a Novel Arsenite Oxidase Gene, arxA, in the Haloalkaliphilic, Arsenite-Oxidizing Bacterium Alkalilimnicola ehrlichii Strain MLHE-1

2010 ◽  
Vol 192 (14) ◽  
pp. 3755-3762 ◽  
Author(s):  
Kamrun Zargar ◽  
Shelley Hoeft ◽  
Ronald Oremland ◽  
Chad W. Saltikov

ABSTRACT Although arsenic is highly toxic to most organisms, certain prokaryotes are known to grow on and respire toxic metalloids of arsenic (i.e., arsenate and arsenite). Two enzymes are known to be required for this arsenic-based metabolism: (i) the arsenate respiratory reductase (ArrA) and (ii) arsenite oxidase (AoxB). Both catalytic enzymes contain molybdopterin cofactors and form distinct phylogenetic clades (ArrA and AoxB) within the dimethyl sulfoxide (DMSO) reductase family of enzymes. Here we report on the genetic identification of a “new” type of arsenite oxidase that fills a phylogenetic gap between the ArrA and AoxB clades of arsenic metabolic enzymes. This “new” arsenite oxidase is referred to as ArxA and was identified in the genome sequence of the Mono Lake isolate Alkalilimnicola ehrlichii MLHE-1, a chemolithoautotroph that can couple arsenite oxidation to nitrate reduction. A genetic system was developed for MLHE-1 and used to show that arxA (gene locus ID mlg_0216) was required for chemoautotrophic arsenite oxidation. Transcription analysis also showed that mlg_0216 was only expressed under anaerobic conditions in the presence of arsenite. The mlg_0216 gene is referred to as arxA because of its greater homology to arrA relative to aoxB and previous reports that implicated Mlg_0216 (ArxA) of MLHE-1 in reversible arsenite oxidation and arsenate reduction in vitro. Our results and past observations support the position that ArxA is a distinct clade within the DMSO reductase family of proteins. These results raise further questions about the evolutionary relationships between arsenite oxidases (AoxB) and arsenate respiratory reductases (ArrA).

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1102
Author(s):  
Galina N. Raldugina ◽  
Sergey V. Evsukov ◽  
Liliya R. Bogoutdinova ◽  
Alexander A. Gulevich ◽  
Ekaterina N. Baranova

In this study the transgenic lines (TLs) of tobacco (Nicotianatabacum L.), which overexpress the heterologous gene encoding the bacterial enzyme choline oxidase were evaluated. The goal of our work is to study the effect of choline oxidase gene expression on the sensitivity of plant tissues to the action of NaCl. The regenerative capacity, rhizogenesis, the amount of photosynthetic pigments and osmotically active compounds (proline and glycine betaine) were assessed by in vitro cell culture methods using biochemical and morphological parameters. Transgenic lines with confirmed expression were characterized by high regeneration capacity from callus in the presence of 200 mmol NaCl, partial retention of viability at 400 mmol NaCl. These data correlated with the implicit response of regenerants and whole plants to the harmful effects of salinity. They turned out to be less sensitive to the presence of 200 mmol NaCl in the cultivation medium, in contrast to the WT plants.


1986 ◽  
Vol 6 (5) ◽  
pp. 1552-1561
Author(s):  
R Esteban ◽  
R B Wickner

Killer strains of Saccharomyces cerevisiae bear at least two different double-stranded RNAs (dsRNAs) encapsidated in 39-nm viruslike particles (VLPs) of which the major coat protein is coded by the larger RNA (L-A dsRNA). The smaller dsRNA (M1 or M2) encodes an extracellular protein toxin (K1 or K2 toxin). Based on their densities on CsCl gradients, L-A- and M1-containing particles can be separated. Using this method, we detected a new type of M1 dsRNA-containing VLP (M1-H VLP, for heavy) that has a higher density than those previously reported (M1-L VLP, for light). M1-H and M1-L VLPs are present together in the same strains and in all those we tested. M1-H, M1-L, and L-A VLPs all have the same types of proteins in the same approximate proportions, but whereas L-A VLPs and M1-L VLPs have one dsRNA molecule per particle, M1-H VLPs contain two M1 dsRNA molecules per particle. Their RNA polymerase produces mainly plus single strands that are all extruded in the case of M1-H particles but are partially retained inside the M1-L particles to be used later for dsRNA synthesis. We show that M1-H VLPs are formed in vitro from the M1-L VLPs. We also show that the peak of M1 dsRNA synthesis is in fractions lighter than M1-L VLPs, presumably those carrying only a single plus M1 strand. We suggest that VLPs carrying two M1 dsRNAs (each 1.8 kilobases) can exist because the particle is designed to carry one L-A dsRNA (4.5 kilobases).


Cancers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 5637
Author(s):  
Maristella Maggi ◽  
Greta Pessino ◽  
Isabella Guardamagna ◽  
Leonardo Lonati ◽  
Cristina Pulimeno ◽  
...  

E. coli L-asparaginase is an amidohydrolase (EC 3.5.1.1) which has been successfully used for the treatment of Acute Lymphoblastic Leukemia for over 50 years. Despite its efficacy, its side effects, and especially its intrinsic immunogenicity, hamper its usage in a significant subset of cases, thus limiting therapeutic options. Innovative solutions to improve on these drawbacks have been attempted, but none of them have been truly successful so far. In this work, we fully replaced the enzyme scaffold, generating an active, miniaturized form of L-asparaginase by protein engineering of a camel single domain antibody, a class of antibodies known to have a limited immunogenicity in humans. We then targeted it onto tumor cells by an antibody scFv fragment directed onto the CD19 B-cell surface receptor expressed on ALL cells. We named this new type of nanobody-based antibody-drug conjugate “Targeted Catalytic Nanobody” (T-CAN). The new molecule retains the catalytic activity and the binding capability of the original modules and successfully targets CD19 expressing cells in vitro. Thanks to its theoretically reduced immunogenic potential compared to the original molecule, the T-CAN can represent a novel approach to tackle current limitations in L-asparaginase usage.


Nanoscale ◽  
2014 ◽  
Vol 6 (5) ◽  
pp. 2855-2860 ◽  
Author(s):  
Haibo Wang ◽  
Wei Lu ◽  
Tianmei Zeng ◽  
Zhigao Yi ◽  
Ling Rao ◽  
...  

A new type of multi-functional NaErF4 nanoprobe with enhanced red upconversion emission was developed and used for in vitro cell, in vivo X-ray and T2-weighted magnetic resonance imaging for the first time.


PLoS ONE ◽  
2018 ◽  
Vol 13 (9) ◽  
pp. e0204325
Author(s):  
Junguo Liu ◽  
Ming Zhao ◽  
Wei Song ◽  
Lingbo Ma ◽  
Xiu Li ◽  
...  

2021 ◽  
Author(s):  
Jun Yang ◽  
Lin Sun ◽  
Shuhan Hui ◽  
Peng Zhang ◽  
Jian Li ◽  
...  

A new type of Ag@SnS2 was established with Ag decorated on SnS2 surface for improved photothermal conversion capability. Ag@SnS2 exhibited a robust in vitro antibacterial effect and in vivo wound disinfection under NIR laser irradiation.


1993 ◽  
Vol 61 ◽  
pp. 78
Author(s):  
Shigeru Taguchi ◽  
Kimihiro Ogino ◽  
Chiaki Shirato ◽  
Isao Aoju ◽  
Kyozo Ishikawa ◽  
...  

2020 ◽  
Vol 117 (51) ◽  
pp. 32370-32379
Author(s):  
Olga A. Patutina ◽  
Svetlana K. Gaponova (Miroshnichenko) ◽  
Aleksandra V. Sen’kova ◽  
Innokenty A. Savin ◽  
Daniil V. Gladkikh ◽  
...  

The design of modified oligonucleotides that combine in one molecule several therapeutically beneficial properties still poses a major challenge. Recently a new type of modified mesyl phosphoramidate (or µ-) oligonucleotide was described that demonstrates high affinity to RNA, exceptional nuclease resistance, efficient recruitment of RNase H, and potent inhibition of key carcinogenesis processes in vitro. Herein, using a xenograft mouse tumor model, it was demonstrated that microRNA miR-21–targeted µ-oligonucleotides administered in complex with folate-containing liposomes dramatically inhibit primary tumor growth via long-term down-regulation of miR-21 in tumors and increase in biosynthesis of miR-21–regulated tumor suppressor proteins. This antitumoral effect is superior to the effect of the corresponding phosphorothioate. Peritumoral administration of µ-oligonucleotide results in its rapid distribution and efficient accumulation in the tumor. Blood biochemistry and morphometric studies of internal organs revealed no pronounced toxicity of µ-oligonucleotides. This new oligonucleotide class provides a powerful tool for antisense technology.


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