Comparative characterization of glutamine synthetase isoforms from Canavalia lineata in biochemical and immunological aspects

Choi, Yang Ae; Kwon, Young Jun

doi:10.1016/s0168-9452(98)00059-4

Cited by 4 publications

(1 citation statement)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It catalyses the reaction of NH 4 + with glutamate to glutamine with the aid of ATP (Choi & Kwon 1998). GDH-NADH also operates in the assimilation of NH 4 + thereby complementing the enzymes of the GS-GOGAT cycle in the synthesis of glutamate, especially under conditions of stress (Srivastava & Singh 1987).…”

Section: Introductionmentioning

confidence: 99%

Effects of different ammoniacal nitrogen sources on N-metabolism of the atmospheric bromeliad Tillandsia pohliana Mez

Tamaki

Mercier

2001

Rev. bras. Bot.

View full text Add to dashboard Cite

-(Effects of different ammoniacal nitrogen sources on N-metabolism of the atmospheric bromeliad Tillandsia pohliana Mez). Increasing levels of atmospheric ammonia from anthropogenic sources have become a serious problem for natural vegetation. Short-term effects of different ammoniacal sources on the N metabolism of Tillandsia pohliana, an atmospheric bromeliad, were investigated. One-year-old, aseptically grown plants were transferred to a modified Knudson medium lacking N for three weeks. Plants were subsequently transferred to Knudson media supplemented with 0.5, 1.0, or 1.5 mM of N in the forms of NH 3 or NH 4 + as the sole N source. The activities of glutamine synthetase (GS) and glutamate dehydrogenase (GDH-NADH) were determined after 40 h. The GS activity was stimulated significantly by increasing the levels of the gaseous form. The GDH-NADH activity increased significantly under increasing N concentrations with NH 3 , while no significant differences were observed with NH 4 + as a N source. These results may reflect a faster NH 3 absorption by T. pohliana compared to NH 4 + uptake. The increased activity of GDH-NADH in NH 3 treatment may play a role in protecting the cells from the toxic effects of increased endogenous level of free ammonium. A raise in the concentration of N, especially in the form of NH 3 , greatly increased the content of free amino acids and soluble proteins. A possible utilisation of T. pohliana to evaluate the changes of atmospheric gaseous ammonia is proposed.RESUMO -(Efeitos de diferentes fontes amoniacais sobre o metabolismo de nitrogênio da bromélia atmosférica Tillandsia pohliana Mez). As fontes antropogênicas de amônia atmosférica têm se tornado um problema sério para a vegetação natural. No presente trabalho foram analisados os efeitos da aplicação de diferentes fontes amoniacais sobre o metabolismo do nitrogênio de Tillandsia pohliana, uma bromélia atmosférica. As sementes foram germinadas in vitro e as plantas cresceram em meio de cultura de Knudson por um ano. Após esse período, elas foram transferidas para o meio de Knudson sem as fontes nitrogenadas originais. Três semanas depois, as plantas foram colocadas nesse mesmo meio de cultura, porém, suplementado com 0,5, 1,0 ou 1,5 mM de N nas formas de NH 3 ou NH 4 + como fontes únicas de nitrogênio. O tempo de exposição a essas fontes foi de 40 h. As atividades enzimáticas da glutamina sintetase (GS) e da glutamato desidrogenase (GDH-NADH) foram analisadas. Os teores endógenos de amônio, de aminoácidos livres e de proteínas solúveis, presentes nos eixos caulinares dessa bromélia, também, foram determinados. As atividades da GS e da GDH-NADH foram estimuladas, significativamente, com o aumento do nitrogênio na forma gasosa. Esses resultados podem refletir a rápida absorção de NH 3 pela planta. Entretanto, a atividade aminante da GDH não apresentou diferença significativa em resposta ao aumento do N na forma de NH 4 + . Provavelmente, o incremento na atividade da GDH-NADH, no tratamento com NH 3 , está relacionado com...

show abstract

Section: Introductionmentioning

confidence: 99%

Effects of different ammoniacal nitrogen sources on N-metabolism of the atmospheric bromeliad Tillandsia pohliana Mez

Tamaki

Mercier

2001

Rev. bras. Bot.

View full text Add to dashboard Cite

show abstract

Molecular cloning and characterization of glutamine synthetase, a tegumental protein from Schistosoma japonicum

et al. 2012

View full text Add to dashboard Cite

Glutamine synthetase catalyzes the synthesis of glutamine, providing nitrogen for the production of purines, pyrimidines, amino acids, and other compounds required in many pivotal cellular events. Herein, a full-length cDNA encoding Schistosoma japonicum glutamine synthetase (SjGS) was isolated from 21-day schistosomes. The entire open reading frame of SjGS contains a 1,095-bp coding region corresponding to 364 amino acids with a calculated molecular weight of 40.7 kDa. NCBIP blast shows that the putative amino acid of SjGS contains a classic β-grasp domain and a catalytic domain of glutamine synthetase. The relative mRNA expression of SjGS was evaluated in 7-, 13-, 21-, 28-, 35-, and 42-day worms of S. japonicum in the final host and higher expression at day 21, and 42 worms were observed. This protein was also detected in worm extracts using Western blot. Immunofluorescence studies indicated that the SjGS protein was mainly distributed on tegument and parenchyma in 28-day adult worms. The recombinant glutamine synthetase with a molecular weight of 45 kDa was expressed in Escherichia coli and purified in its active form. The enzyme activity of the recombinant protein was 3.30 ± 0.67 U.μg-1. The enzyme activity was highly stable over a wide range of pH (6-9) and temperature (25-40 °C) under physiological conditions. The transcription of SjGS was upregulated in praziquantel-treated worms at 2-, 4-, and 24-h posttreatment compared with the untreated control. As a first step towards the clarification of the role of glutamine synthetase in schistosome species, we have cloned and characterized cDNAs encoding SjGS in S. japonicum, and the data presented suggest that SjGS is an important molecule in the development of the schistosome.

show abstract

The plastidic glutamine synthetase activity is directly modulated by means of redox change at two unique cysteine residues

1999

View full text Add to dashboard Cite

Comparative characterization of glutamine synthetase isoforms from Canavalia lineata in biochemical and immunological aspects

Cited by 4 publications

References 34 publications

Effects of different ammoniacal nitrogen sources on N-metabolism of the atmospheric bromeliad Tillandsia pohliana Mez

Effects of different ammoniacal nitrogen sources on N-metabolism of the atmospheric bromeliad Tillandsia pohliana Mez

Molecular cloning and characterization of glutamine synthetase, a tegumental protein from Schistosoma japonicum

The plastidic glutamine synthetase activity is directly modulated by means of redox change at two unique cysteine residues

Contact Info

Product

Resources

About