Identification of nitrogen mineralization enzymes, l-amino acid oxidases, from the ectomycorrhizal fungi Hebeloma spp. and Laccaria bicolor

Nuutinen, Jaro T.; Timonen, Sari

doi:10.1016/j.mycres.2008.06.023

Cited by 45 publications

(42 citation statements)

References 62 publications

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“…H. cylindrosporum strains h7 (Gay et al, 1993) and CBS 558.96 (Centraalbureau voor Schimmelcultures, Utrecht, Netherlands) were grown for 18-35 days on cellophane-covered modified Hagem's medium. Soluble cellular enzymes were extracted by first grinding the freshly collected hyphae in mortar and then disintegrating with ultrasound (Nuutinen & Timonen, 2008).…”

Section: Methodsmentioning

confidence: 99%

“…SDS-PAGE gels were stained for Lao activity (H 2 O 2 production) with the peroxidase-o-dianisidine method, with L-phenylalanine or Lleucine as the substrates (Nuutinen & Timonen, 2008). The amino acids were omitted from negative control staining.…”

Section: Methodsmentioning

confidence: 99%

“…and Laccaria bicolor (Nuutinen & Timonen, 2008). The activities were localized intracellularly and they were especially high in nitrogen-rich growth conditions.…”

Section: Introductionmentioning

confidence: 98%

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l-Amino acid oxidase of the fungus Hebeloma cylindrosporum displays substrate preference towards glutamate

et al. 2012

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Catabolism of amino acids is a central process in cellular nitrogen turnover, but only a few of the mechanisms involved have been described from basidiomycete fungi. This study identified one such mechanism, the L-amino acid oxidase (Lao1) enzyme of Hebeloma cylindrosporum, by 2D gel separation and MS. We determined genomic DNA sequences of lao1 and part of its upstream gene, a putative pyruvate decarboxylase (pdc2), and cloned the cDNA of lao1. The two genes were also identified and annotated from the genome of Laccaria bicolor. The lao1 and pdc2 gene structures were conserved between the two fungi. The intergenic region of L. bicolor possessed putative duplications not detected in H. cylindrosporum. Lao1 sequences possessed dinucleotide-binding motifs typical for flavoproteins. Lao1 was less than 23 % identical to Lao sequences described previously. Recombinant Lao1 of H. cylindrosporum was expressed in Escherichia coli, purified and refolded with SDS to gain catalytic activity. The enzyme possessed broad substrate specificity: 37 L-amino acids or derivatives served as effective substrates. The highest activities were recorded with L-glutamate, but positively charged and aromatic amino acids were also accepted. Michaelis constants for six amino acids varied from 0.5 to 6.7 mM. We have thus characterized a novel type of Lao-enzyme and its gene from the basidiomycete fungus H. cylindrosporum.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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l-Amino acid oxidase of the fungus Hebeloma cylindrosporum displays substrate preference towards glutamate

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“…LAAO широко представлены в природе: они обнаружены у многих видов змей [17][18][19][20][21], насекомых [22], некоторых видов бактерий [23][24][25][26][27][28][29], грибов [30][31][32][33], водорослей [34,35], моллюсков и рыб [36][37][38][39][40][41]. У млекопитающих LAAO выделены из печени, почек, мозга [42,43], секрета молочных желёз (у мышей) [44], и из полиморфноядерных лейкоцитов [45].…”

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L-amino acid oxidases: properties and molecular mechanisms of action

et al. 2012

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За последние 10-15 лет оксидазы L-аминокислот (LAAO) стали предметом интенсивного изучения в силу их разнообразного действия на различные биологические объекты. В обзоре суммирована информация об источниках, строении, физико-химических и каталитических свойствах LAAO. Приведены данные о бактериостатических, бактерицидных, противогрибковых, противопротозойных, противовирусных, антипролиферативных и противоопухолевых эффектах этих ферментов, а также о неоднозначном о влиянии на агрегацию тромбоцитов. Особое внимание уделено анализу данных литературы, посвященных выяснению молекулярных механизмов действия LAAO.Основой проявляемых LAAO уникальных свойств является, вероятно, снижение под их действием уровня пула аминокислот (в том числе и незаменимых), а также образование пероксида водорода, влияние которого на клетки опосредовано через АФК и развитие ряда биологических механизмов апоптоза и некроза. Наличие углеводных компонентов в молекулах LAAO способствует их связыванию с поверхностью клеток и созданию высоких локальных концентраций пероксида водорода. Широкий спектр биологических эффектов LAAO in vivo разнообразен и опосредован, как правило, их функциональным значением, например, в головном мозге мышей катализируемая LAAO реакция является единственным путём превращения L-лизина, в молоке мышей LAAO выполняет бактерицидную функцию, а в лейкоцитах LAAO принимают участие в реализации их системного противоинфекционного действия. Протекторный эффект можно также отнести и к оксидазам из других многочисленных источников: микроскопических грибов, ядов змей и морских организмов.Ключевые слова: оксидазы L-аминокислот (LААО), L-лизин-альфа-оксидаза, цитотоксичность, противоопухолевые свойства, противовирусные свойства, апоптоз.ВВЕДЕНИЕ. До 90-х годов прошлого столетия научные исследования оксидаз L-аминокислот (LAAO) были, в основном, посвящены их ферментативным и физико-химическим свойствам [1][2][3][4]. В последние десятилетия интерес к LAAO существенно возрос. Разработаны лабораторные методы выделения и очистки LAAO из многочисленных источников разной природы, изучена первичная структура, а также пространственная структура ряда оксидаз [5][6][7][8]. Получено много интересных данных о биологических эффектах оксидаз L-аминокислот [9][10][11][12][13][14][15][16]. 372* -адресат для переписки

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“…The toxicity of the snake venom has been attributed to a class of toxins, the L-amino acid oxidases (svLAAO), although the precise mechanism of action of these enzymes and their role in snake toxicity are not well understood. Previous studies have reported that svLAAO may be related to defense mechanisms against natural agents, as parasites and bacteria (Iijima et al, 2003;Nuutinen & Timonen, 2008;Kitani et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

Bothrops pirajai snake venom L-amino acid oxidase: in vitro effects on infection of Toxoplasma gondii in human foreskin fibroblasts

Izidoro¹,

Alves²,

Rodrigues³

et al. 2011

Rev. bras. farmacogn.

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Abstract:The effect of an L-amino acid oxidase isolated from Bothrops pirajai snake venom (BpirLAAO-I) was investigated on infection of Toxoplasma gondii in human foreskin fibroblasts (HFF). The cytotoxic activity of BpirLAAO-I on HFF cells showed a dose-dependent toxicity with median cytotoxic dose (TD50) of 11.8 µg/mL. BpirLAAO-I induced considerable dose-dependent decrease in the T. gondii infection index under two different conditions, treatment of tachyzoites before infection or treatment of HFF cells after infection. A maximal inhibition of infection (56%) was found for treatment before infection, with a median inhibitory dose (ID50) at 1.83 µg/mL and selectivity index (SI) at 6.45. For treatment after infection, it was observed a maximal inhibition of infection at 65%, ID50 of 1.20 µg/mL and SI of 9.83. The treatment before infection was also effective to reduce intracellular parasitism up to 62%, although presenting higher values of ID50 (3.14 µg/mL) and lower values of SI (3.76). However, treatment after infection was not effective, suggesting that the enzyme seems to have no effect on the parasite intracellular replication for this condition. In conclusion, BpirLAAO-I was more effective to inhibit the infection of neighboring cells and consequently parasite dissemination than primary infection and parasite replication. Thus, the effect of BpirLAAO-I described herein could be taken into account for the development of new synthetic anti-parasite therapeutic agents.

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Identification of nitrogen mineralization enzymes, l-amino acid oxidases, from the ectomycorrhizal fungi Hebeloma spp. and Laccaria bicolor

Cited by 45 publications

References 62 publications

l-Amino acid oxidase of the fungus Hebeloma cylindrosporum displays substrate preference towards glutamate

l-Amino acid oxidase of the fungus Hebeloma cylindrosporum displays substrate preference towards glutamate

L-amino acid oxidases: properties and molecular mechanisms of action

Bothrops pirajai snake venom L-amino acid oxidase: in vitro effects on infection of Toxoplasma gondii in human foreskin fibroblasts

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